SHOT PROCESSING DEVICE

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority from Japanese Patent Application No. 2024-225532 filed with the Japan Patent Office on Dec. 20, 2024, the contents of which are herein incorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to a shot processing device.

BACKGROUND

A shot blasting device that processes an outer surface of a cylindrical workpiece is known. For example, Japanese Unexamined Patent Application Publication No. 2023-66123 describes a cylindrical body polishing structure including a rotation mechanism that rotates a cylindrical body around its axis, a polishing device capable of emitting abrasive material toward an outer peripheral surface of the cylindrical body, and a moving mechanism that moves the polishing device along the outer peripheral surface of the cylindrical body in an axial direction of the cylindrical body.

SUMMARY

In the cylindrical body polishing structure described in Japanese Unexamined Patent Application Publication No. 2023-66123, an elastic member is provided at an opening end of a cabinet (hopper) to which the polishing device is attached, and the elastic member is pressed against the outer surface of the cylindrical body. Workpieces to be processed include workpieces of various diameters and tapered workpieces whose diameter decreases toward a tip. For this reason, since the curvature of the outer surface may differ for each workpiece to be processed, a gap may be formed between the elastic member and the outer surface, allowing particulate matter, including projected shot media, to leak to the outside through the gap.

The present disclosure describes a shot processing device capable of suppressing leakage of particulate matter.

A shot processing device according to one aspect of the present disclosure is a device that performs shot processing on an outer surface of a cylindrical workpiece. The shot processing device includes a cabinet, a projector, and a seal structure. The cabinet defines a projection chamber and includes an opening. The opening communicates with the projection chamber and opens toward the outer surface of the workpiece. The projector is provided in the cabinet and projects shot media toward the outer surface of the workpiece via the opening. The seal structure is provided along an opening edge of the opening. The seal structure includes a magnet unit. The magnet unit is provided on a portion of the opening edge, the portion extending in a first direction intersecting a central axis of the workpiece.

According to each aspect and each embodiment of the present disclosure, leakage of particulate matter can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a configuration diagram schematically showing a shot processing system including a shot processing device according to one embodiment.

FIG. 2 is a perspective view showing the shot processing device shown in FIG. 1.

FIG. 3 is a diagram for explaining a circulation path of shot media.

FIG. 4 is a side view showing the moving mechanism and the tilting mechanism of the shot processing device shown in FIG. 2.

FIG. 5 is a front view showing the moving mechanism and the tilting mechanism of the shot processing device shown in FIG. 2.

FIG. 6 is a configuration diagram schematically showing the projection device shown in FIG. 2.

FIG. 7 is a plan view of the projection device shown in FIG. 6.

FIG. 8 is a plan view showing an upper seal structure included in the seal structure shown in FIG. 6.

FIG. 9 is a cross-sectional view taken along line IX-IX of FIG. 8.

FIG. 10 is a side view showing a side seal structure included in the seal structure shown in FIG. 6.

FIG. 11 is a front view of the side seal structure shown in FIG. 10.

FIG. 12 is a cross-sectional view taken along line XII-XII of FIG. 11.

FIG. 13 is a diagram for explaining an operating principle of the side seal structure shown in FIG. 10.

FIG. 14 is a diagram showing a lower seal structure included in the seal structure shown in FIG. 6.

FIG. 15 is a cross-sectional view taken along line XV-XV of FIG. 14.

FIG. 16 is a flowchart showing a shot processing method performed by the control device shown in FIG. 1.

FIG. 17 is a flowchart showing the attitude control of FIG. 16 in detail.

FIG. 18 is a diagram for explaining a processing area of the workpiece shown in FIG. 1.

FIG. 19 is a diagram for explaining an initial position of the projection device shown in FIG. 6.

FIG. 20 is a diagram for explaining a measurement position of the projection device shown in FIG. 6.

FIG. 21 is a diagram for explaining tilting of the projection device shown in FIG. 6.

FIG. 22 is a diagram for explaining a target position of the projection device shown in FIG. 6.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description will be omitted. In each figure, an XYZ coordinate system may be shown. The Y-axis direction is a direction intersecting (for example, orthogonal to) the X-axis direction and the Z-axis direction. The Z-axis direction is a direction intersecting (for example, orthogonal to) the X-axis direction and the Y-axis direction. Unless otherwise specified in the text, the X-axis direction indicates a lateral direction (second direction), the Y-axis direction indicates a front-rear direction, and the Z-axis direction indicates an up-down direction (first direction). A “plan view” is a view from above and refers to an XY plan view. A “side view” is a view from the side and refers to a YZ plan view. A “front view” is a view from the front and refers to an XZ plan view.

A shot processing system including a shot processing device according to one embodiment will be described with reference to FIG. 1. FIG. 1 is a configuration diagram schematically showing a shot processing system including a shot processing device according to one embodiment.

A shot processing system 1 shown in FIG. 1 is a system for performing shot processing on an outer surface Wa of a cylindrical workpiece W. The workpiece W is a long, large-diameter cylindrical body (columnar body). A length of the workpiece W along a central axis (hereinafter, referred to as “axis AX1”) is, for example, 30 m to 40 m. A diameter of the workpiece W is, for example, 5 m to 10 m. The diameter of the workpiece W may be constant over the entire length of the workpiece W, or may decrease from one end to the other end. An example of the workpiece W is a tower for wind power generation. The shot processing system 1 includes a shot processing device 10 and a rotation mechanism 100.

The shot processing device 10 is a device that performs shot processing on the outer surface Wa of the workpiece W. The shot processing device 10 performs shot processing on the outer surface Wa while the workpiece W is being rotated around the axis AX1 of the workpiece W by the rotation mechanism 100. The shot processing device 10 performs shot processing on the outer surface Wa for each processing area obtained by dividing the outer surface Wa along the axis AX1. The detailed configuration of the shot processing device 10 will be described later.

The rotation mechanism 100 is a mechanism that rotates the workpiece W around the axis AX1. The rotation mechanism 100 includes a base 101 and turning rolls 102. The base 101 is placed on a floor surface and supports the turning rolls 102. In the present embodiment, four turning rolls 102 are provided on the base 101. The four turning rolls 102 rotatably support the workpiece W around the axis AX1. The four turning rolls 102 support the workpiece W such that the axis AX1 is substantially parallel to the floor surface. Each turning roll 102 is configured to be rotatable around an axis extending in the same direction as the axis AX1 by a drive motor (not shown). By rotationally driving the four turning rolls 102 in the same direction about their axes, the workpiece W is rotated about the axis AX1.

Next, the configuration of the shot processing device 10 will be described in detail with reference to FIGS. 2 to 5. FIG. 2 is a perspective view showing the shot processing device shown in FIG. 1. FIG. 3 is a diagram for explaining a circulation path of shot media. FIG. 4 is a side view showing the moving mechanism and the tilting mechanism of the shot processing device shown in FIG. 2. FIG. 5 is a front view showing the moving mechanism and the tilting mechanism of the shot processing device shown in FIG. 2. In FIG. 3, portions of the shot processing device 10 having low relevance to the circulation path of the shot media are omitted from illustration. In FIGS. 4 and 5, portions of the shot processing device 10 having low relevance to the moving mechanism and the tilting mechanism are omitted from illustration.

As shown in FIGS. 2 to 5, the shot processing device 10 includes a supply device 11, a projection device 12, a collection device 13, a classification device 14, a moving mechanism 15, a tilting mechanism 16, and a control device 17 (see FIG. 1).

The supply device 11 is a device that supplies shot media to the projection device 12. The supply device 11 is provided above the projection device 12. The supply device 11 includes a shot media tank 11a and a gate 11b. The shot media tank 11a stores shot media. The gate 11b is provided in a lower portion of the shot media tank 11a and adjusts the amount of shot media from the shot media tank 11a to the projection device 12.

The projection device 12 is a device that projects shot media onto the outer surface Wa of the workpiece W. The projection device 12 projects shot media onto the outer surface Wa while the workpiece W is being rotated around the axis AX1. The projection device 12 projects shot media onto a region of the outer surface Wa that moves upward from bottom to top (i.e., an ascending region of the outer surface Wa). The projection device 12 includes a cabinet 21, a projector 22, a receiving member 23, and a rotary shaft 24. The cabinet 21 is a box-shaped member that defines a projection chamber 21a. The size of the projection chamber 21a is determined in consideration of the distance between the projector 22 and the outer surface Wa, the projection range, and the distribution. The cabinet 21 is configured to be tiltable around an axis AX2 of the rotary shaft 24.

The cabinet 21 includes an opening 21b on a surface facing the outer surface Wa. The opening 21b communicates with the projection chamber 21a and opens toward the outer surface Wa of the workpiece W. The opening 21b has a rectangular shape. The opening 21b need only be of a size sufficient to permit shot processing.

The projector 22 is provided in the cabinet 21 and projects shot media toward the outer surface Wa of the workpiece W via the projection chamber 21a and the opening 21b. A projection method of the projector 22 may be an air type or an impeller type (centrifugal type). Examples of the air type include a gravity type, a suction type, a direct pressure type (pressurized type), and a blower type. In the present embodiment, an impeller type will be used for description. Examples of the shot media include steel shot and steel grit. The type of shot media can be appropriately selected according to the required specifications of the shot processing, the type of the workpiece W, and the like.

The receiving member 23 is a member that receives particulate matter generated by the shot processing. The particulate matter includes the shot media used for the shot processing, cutting powder of the workpiece W generated by the shot processing, and the like. The receiving member 23 is provided so as to surround a lower portion of the cabinet 21. A discharge port 23a for discharging the particulate matter is provided at a bottom portion of the receiving member 23. The receiving member 23 includes a conveying screw 23b provided above the discharge port 23a. The conveying screw 23b collects the particulate matter that has fallen to the bottom portion of the receiving member 23 to the discharge port 23a and discharges it from the discharge port 23a. The detailed configuration of the projection device 12 will be described later.

The collection device 13 is a device that collects the particulate matter generated by the shot processing. The collection device 13 collects the particulate matter discharged from the discharge port 23a and supplies the collected particulate matter to the classification device 14. The collection device 13 includes a screw conveyor 13a and a bucket elevator 13b.

The screw conveyor 13a is provided below the projection device 12 and extends horizontally. The screw conveyor 13a receives the particulate matter generated by the shot processing from the projection device 12 and conveys it toward the bucket elevator 13b. The screw conveyor 13a includes a shaft and blades provided helically on an outer peripheral surface of the shaft. As the shaft rotates, the particulate matter is conveyed by the blades. The bucket elevator 13b conveys the particulate matter conveyed by the screw conveyor 13a to the classification device 14. The bucket elevator 13b circulates a plurality of buckets. Each bucket scoops up the particulate matter, conveys it upward, and supplies it to the classification device 14.

The classification device 14 is a device that selects reusable shot media from the particulate matter supplied from the collection device 13. The classification device 14 is provided above the supply device 11 and supplies the reusable shot media to the supply device 11.

The moving mechanism 15 is a mechanism that moves the projection device 12 in a direction along the axis AX1 (hereinafter, may be referred to as a “lateral direction”) and in a direction intersecting (here, orthogonal to) the lateral direction (hereinafter, may be referred to as a “front-rear direction”). In the present embodiment, the moving mechanism 15 integrally moves the supply device 11, the projection device 12, the collection device 13, the classification device 14, and the tilting mechanism 16. The moving mechanism 15 includes a rail 15a, a carriage 15b, a rail 15c, a carriage 15d, and a cylinder 15e.

The rail 15a is laid on the floor surface and extends substantially parallel to the axis AX1. The carriage 15b travels on the rail 15a. The carriage 15b moves in the lateral direction, for example, by motor drive. A rail 15c extending in the front-rear direction is laid on an upper surface of the carriage 15b. The carriage 15d travels on the rail 15c. The carriage 15d is moved in the front-rear direction by the cylinder 15e installed on the carriage 15b. The configuration of the moving mechanism 15 is not limited to the above-described configuration, and may be any configuration that can integrally move the supply device 11, the projection device 12, the collection device 13, the classification device 14, and the tilting mechanism 16 in the lateral direction and the front-rear direction.

The tilting mechanism 16 is a mechanism that tilts the projection device 12 with the rotary shaft 24 as an axis. In other words, the tilting mechanism 16 tilts the projection device 12 around the axis AX2 of the rotary shaft 24. The tilting mechanism 16 includes a pair of support members 16a and a cylinder 16b. The pair of support members 16a are erected on an upper surface of the carriage 15d and support both ends of the rotary shaft 24 such that the rotary shaft 24 is rotatable around the axis AX2. The cylinder 16b is provided on the carriage 15d so as to be rotatable around an axis extending in the lateral direction. The cylinder 16b includes a piston rod that is advanceable and retractable in the front-rear direction. A tip of the piston rod is connected to a back surface of the projection device 12 below the rotary shaft 24. The cylinder 16b tilts (pivots) the projection device 12 around the axis AX2 by advancing and retracting the piston rod.

The control device 17 is a device (controller) that comprehensively controls the shot processing device 10. The control device 17 is configured as a computer including, for example, a processor such as a central processing unit (CPU), a memory such as a random access memory (RAM) and a read only memory (ROM), and a communication device such as a network card. The control device 17 may be configured as a programmable logic controller (PLC). The control device 17, for example, performs attitude control of the projection device 12 and causes the projection device 12, whose attitude has been controlled, to project the shot media. A shot processing method performed by the control device 17 will be described later.

In the shot processing device 10, shot media is supplied from the shot media tank 11a through the gate 11b to the projector 22, and the shot media is projected by the projector 22 onto the outer surface Wa of the workpiece W via the projection chamber 21a and the opening 21b. As a result, shot processing is performed on the outer surface Wa. The particulate matter generated by the shot processing is collected in the projection chamber 21a and falls from the projection chamber 21a into the receiving member 23 through a gap 21g (see FIG. 6) described later. The particulate matter that has fallen into the receiving member 23 is collected by the conveying screw 23b to the discharge port 23a and discharged from the discharge port 23a. Then, the particulate matter discharged from the discharge port 23a is supplied to the classification device 14 via the screw conveyor 13a and the bucket elevator 13b. Then, in the classification device 14, the particulate matter is separated into reusable shot media and dust, and the reusable shot media is supplied to the shot media tank 11a.

Next, the configuration of the projection device 12 will be described in detail with reference to FIGS. 5 to 7. FIG. 6 is a configuration diagram schematically showing the projection device shown in FIG. 2. FIG. 7 is a plan view of the projection device shown in FIG. 6. In FIG. 7, a seal structure 25, which will be described later, and the like are omitted from illustration.

As shown in FIGS. 5 to 7, the cabinet 21 includes a top plate 211, a pair of side plates 212, a back plate 213, and a pair of inclined plates 214. The pair of side plates 212 face each other in the lateral direction. The back plate 213 faces the opening 21b in the front-rear direction. The back plate 213 is bent into a rearwardly recessed V-shape so as to be bilaterally symmetrical about the center in the lateral direction. A bending angle of the back plate 213 is set so that the projection density becomes uniform in consideration of the projection range and distribution.

The pair of inclined plates 214 are located below the top plate 211 and are inclined such that, as they extend downward, they approach each other in the front-rear direction. The projection chamber 21a is defined by the top plate 211, the pair of side plates 212, the back plate 213, and the pair of inclined plates 214. The opening 21b is defined by a front end portion of the top plate 211, front end portions of the pair of side plates 212, and a front end portion of the front inclined plate 214. A liner (wear-resistant steel plate) is provided on an inner surface of the cabinet 21.

A projection port 21c, an intake port 21d, and a discharge port 21e are provided in the back plate 213. The projector 22 is attached to the projection port 21c, and shot media is projected from the projector 22 into the projection chamber 21a via the projection port 21c. In the present embodiment, two projection ports 21c are provided. One projection port 21c is provided on a right side of the back plate 213, and the other projection port 21c is provided on a left side of the back plate 213. A projection range Rs1 in the lateral direction of the shot media projected from one projector 22 and a projection range Rs2 in the lateral direction of the shot media projected from the other projector 22 overlap each other in a plan view (when viewed from above). In order to avoid interference between the shot media projected from the two projectors 22, the positions (heights) of the two projection ports 21c in the up-down direction may be different from each other.

The intake port 21d is an opening for introducing air from the outside of the projection chamber 21a into the projection chamber 21a. In the present embodiment, the intake port 21d is provided at a central portion in the lateral direction of the back plate 213 of the cabinet 21. The discharge port 21e is an opening for discharging a part of the particulate matter (dust) generated by the shot processing from the inside of the projection chamber 21a. In the present embodiment, two discharge ports 21e are provided at positions that are bilaterally symmetrical.

The cabinet 21 includes a pair of inclined surfaces 21f provided below the opening 21b. The pair of inclined surfaces 21f are inner surfaces of the pair of inclined plates 214 and are inclined so as to approach each other as they go downward. Lower ends of the pair of inclined surfaces 21f are spaced apart from each other, and a gap 21g is formed therebetween. An inclination angle of the inclined surface 21f is set to an angle at which the particulate matter generated by the shot processing is unlikely to stay on the inclined surface 21f in a tilting range of the projection device 12. The particulate matter generated by the shot processing falls from the projection chamber 21a into the receiving member 23 through the gap 21g.

As shown in FIG. 6, the projection device 12 further includes the seal structure 25. The seal structure 25 is a structure for preventing the particulate matter generated by the shot processing from leaking to the outside of the projection chamber 21a. The seal structure 25 is provided along an opening edge of the opening 21b. The seal structure 25 includes an upper seal structure 30 (see FIG. 8), a side seal structure 40 (see FIG. 10), and a lower seal structure 50 (see FIG. 14). The detailed configuration of the seal structure 25 will be described later.

The projection device 12 further includes a distance sensor 26a (first distance sensor), a distance sensor 26b (second distance sensor), a distance sensor 26c (third distance sensor), and a distance sensor 26d (fourth distance sensor). Each of the distance sensors 26a to 26d is attached to the back plate 213 of the cabinet 21 and measures a distance to the outer surface Wa via the opening 21b. The distance sensor 26a and the distance sensor 26b are spaced apart from each other in the up-down direction. The distance sensor 26c and the distance sensor 26d are spaced apart from each other in the up-down direction. The distance sensor 26c is spaced apart from the distance sensor 26a in the lateral direction. The distance sensor 26d is spaced apart from the distance sensor 26b in the lateral direction.

A sensor set (first sensor set) of the distance sensor 26a and the distance sensor 26b is located on a right side in the opening 21b when viewed from a front, and a sensor set (second sensor set) of the distance sensor 26c and the distance sensor 26d is located on a left side in the opening 21b when viewed from the front. A distance from the distance sensor 26a to the opening 21b, a distance from the distance sensor 26b to the opening 21b, a distance from the distance sensor 26c to the opening 21b, and a distance from the distance sensor 26d to the opening 21b are substantially the same. Each of the distance sensors 26a to 26d transmits a measured distance (measured value) to the control device 17. The control device 17 performs attitude control of the projection device 12 based on the measured values from the distance sensors 26a to 26d. Details of the attitude control will be described later.

The projection device 12 further includes a foreign object detection device 27. The foreign object detection device 27 is a device that detects a foreign object present on the outer surface Wa of the workpiece W. The foreign object detection device 27 is attached to the receiving member 23. Specifically, the foreign object detection device 27 is provided upstream of the opening 21b in a rotation direction of the workpiece W.

The foreign object detection device 27 includes, for example, a rod-shaped member protruding toward the outer surface Wa, and a limit switch connected to the rod-shaped member. While the workpiece W is rotating, if a foreign object is present on the outer surface Wa, the foreign object hits a tip of the rod-shaped member. As a result, the rod-shaped member is lifted, thereby switching the limit switch from an OFF state to an ON state. When the limit switch is turned ON, a detection signal indicating that a foreign object has been detected is transmitted to the control device 17.

The control device 17 stops the shot processing when the foreign object is detected. Specifically, the control device 17 stops the rotation mechanism 100 and stops the shot processing device 10. The control device 17 may retract the projection device 12 to an initial position, which will be described later, when the foreign object is detected.

The projection device 12 further includes an inspection device 28. The inspection device 28 is a device that inspects a state of the outer surface Wa of the workpiece W. The inspection device 28 is attached to the top plate 211 of the cabinet 21. Specifically, the inspection device 28 is provided downstream of the opening 21b in the rotation direction of the workpiece W. In the present embodiment, the inspection device 28 includes a surface roughness measuring instrument 28a and a camera 28b. The surface roughness measuring instrument 28a measures a surface roughness of the outer surface Wa and transmits the measured value to the control device 17 as an inspection result. The camera 28b captures an image of the outer surface Wa and transmits the image of the outer surface Wa to the control device 17 as an inspection result.

The control device 17 may change processing conditions of the shot processing based on an inspection result from the inspection device 28. For example, when the control device 17 determines from the image that the projection density is insufficient, the control device 17 increases the projection density by increasing a set value of the projection amount or decreasing a rotation speed of the workpiece W. When the control device 17 determines from the image that the projection density is excessive, the control device 17 decreases the projection density by decreasing the set value of the projection amount or increasing the rotation speed of the workpiece W.

When the surface roughness of the outer surface Wa is low, the control device 17 increases the surface roughness by increasing a particle size of the shot media. The control device 17 may increase the particle size of the shot media by causing the supply device 11 to supply shot media of a larger size and extracting a part of the shot media circulating in the shot processing device 10. Similarly, when the surface roughness of the outer surface Wa is high, the control device 17 decreases the surface roughness by decreasing the particle size of the shot media.

Next, the upper seal structure 30 will be described in detail with reference to FIGS. 8 and 9. FIG. 8 is a plan view showing an upper seal structure included in the seal structure shown in FIG. 6. FIG. 9 is a cross-sectional view taken along line IX-IX of FIG. 8.

As shown in FIGS. 8 and 9, the upper seal structure 30 is provided along an upper edge portion extending in the lateral direction of the opening edge of the opening 21b. The upper edge portion of the opening edge of the opening 21b corresponds to the front end portion of the top plate 211. The upper seal structure 30 includes a plurality of cylinders 31 (drive units), a plurality of guide members 32, a plurality of brackets 33, a plurality of brushes 34 (brush portions), a plurality of elastic bodies 35, and an elastic member 36.

In the present embodiment, the upper seal structure 30 includes three cylinders 31. The three cylinders 31 are installed on an upper surface of the top plate 211 and are arranged in the lateral direction. The upper seal structure 30 includes the same number of guide members 32 as the cylinders 31. One guide member 32 is provided for each cylinder 31 and is disposed on the upper surface of the top plate 211 laterally alongside the corresponding cylinder 31. Each cylinder 31 is arranged so that a piston rod is advanceable and retractable in the front-rear direction. Each guide member 32 is arranged so that a guide rod is advanceable and retractable in the front-rear direction. One bracket 33 is commonly attached to a tip of the piston rod of the cylinder 31 and a tip of the guide rod of the guide member 32 corresponding to the cylinder 31. As a result, the guide rod of the guide member 32 advances and retracts in conjunction with the advance and retract of the piston rod of the corresponding cylinder 31.

One brush 34 and one elastic body 35 are fixed to each bracket 33. In other words, one brush 34 and one elastic body 35 are provided for each bracket 33. Specifically, a base end of the brush 34 is fixed to the bracket 33 so as to be rotatable around an axis extending in a normal direction of the upper surface of the top plate 211 (a direction intersecting the axis AX1 and a direction of advance and retract of the brush 34), and bristles of the brush 34 extend forward from the base end.

The elastic body 35 is provided downstream of the brush 34 in the rotation direction of the workpiece W. A base end of the elastic body 35 is fixed to the bracket 33, and a tip of the elastic body 35 extends forward. The tip of the elastic body 35 protrudes forward beyond a tip of the brush 34. The elastic body 35 is harder than the elastic member 36. The elastic body 35 is, for example, urethane rubber.

One elastic member 36 is commonly fixed to the three brackets 33. The elastic member 36 is a plate material bent into a U-shape that is convex toward the front (the outer surface Wa of the workpiece W). The elastic member 36 is a wear-resistant rubber and has flexibility. Examples of a constituent material of the elastic member 36 include butadiene rubber, styrene-butadiene rubber, urethane rubber, nitrile rubber, and ethylene propylene rubber. The elastic member 36 is provided upstream of the brush 34 in the rotation direction of the workpiece W, extends forward from the three brackets 33, is folded back in a U-shape so as to sandwich the front end portion of the top plate 211 in the up-down direction, and extends rearward. One end of the elastic member 36 is fixed to the three brackets 33, and the other end of the elastic member 36 is fixed to a lower surface of the top plate 211.

The elastic member 36 is provided at the front end portion of the top plate 211. Specifically, the elastic member 36 is provided at the front end portion of the top plate 211 over the entire length of the top plate 211 in the lateral direction. The front end portion of the top plate 211 is sandwiched in the up-down direction by the U-shaped bent elastic member 36. The brush 34 is located on the outer side of the cabinet 21 relative to the elastic member 36. The elastic body 35 is located on the outer side of the cabinet 21 relative to the brush 34.

Each cylinder 31 advances the piston rod until a convex portion of the elastic member 36 comes into contact with the outer surface Wa of the workpiece W, whereby the elastic member 36 is pressed against the outer surface Wa over the entire length of the front end portion of the top plate 211. In other words, each cylinder 31 advances and retracts the elastic member 36 with respect to the outer surface Wa of the workpiece W. The plurality of brushes 34 are advanced and retracted with respect to the outer surface Wa of the workpiece W by the plurality of cylinders 31.

Next, the side seal structure 40 will be described in detail with reference to FIGS. 10 to 13. FIG. 10 is a side view showing a side seal structure included in the seal structure shown in FIG. 6. FIG. 11 is a front view of the side seal structure shown in FIG. 10. FIG. 12 is a cross-sectional view taken along line XII-XII of FIG. 11. FIG. 13 is a diagram for explaining an operating principle of the side seal structure shown in FIG. 10. In FIG. 10, the upper seal structure 30, the lower seal structure 50, and the like are omitted from illustration.

As shown in FIGS. 10 to 12, the side seal structure 40 is provided along a side edge portion extending in the up-down direction of the opening edge of the opening 21b. The side edge portion of the opening edge of the opening 21b corresponds to the front end portion of the side plate 212. The side seal structure 40 includes a cylinder 41 (drive unit), a guide member 42, a bracket 43, a magnet unit 44, a liner 45, a brush 46, and a roller 47 (positioning member).

The cylinder 41 is installed on an outer surface of the side plate 212. The guide member 42 is arranged alongside the cylinder 41 in the up-down direction. The cylinder 41 is arranged so that a piston rod is advanceable and retractable in the front-rear direction. The guide member 42 is arranged so that a guide rod is advanceable and retractable in the front-rear direction. One bracket 43 is commonly attached to a tip of the piston rod of the cylinder 41 and a tip of the guide rod of the guide member 42. As a result, the guide rod of the guide member 42 advances and retracts in conjunction with the advance and retract of the piston rod of the cylinder 41.

The bracket 43 is a plate-shaped member extending in the up-down direction. The bracket 43 includes a central portion 43a, an inner portion 43b, and an outer portion 43c. The central portion 43a is located in front of the front end portion of the side plate 212 and extends in the lateral direction from an inside to an outside of the projection chamber 21a. The inner portion 43b extends rearward from an inner end of the central portion 43a. The outer portion 43c is inclined so as to extend rearward as it goes outward from an outer end of the central portion 43a.

The magnet unit 44, the liner 45, the brush 46, and the roller 47 are fixed to the bracket 43. Specifically, the magnet unit 44 is fixed to the central portion 43a, the liner 45 is fixed to the inner portion 43b, and the brush 46 is fixed to the outer portion 43c. In other words, the liner 45 is located on the inner side of the cabinet 21 relative to the magnet unit 44, and the brush 46 is located on the outer side of the cabinet 21 relative to the magnet unit 44. The brush 46 is provided along the outer portion 43c. Specifically, a base end of the brush 46 is fixed to the outer portion 43c, and the brush 46 extends forward while being inclined in the lateral direction from the outer portion 43c to the front of the magnet unit 44.

The magnet unit 44 is provided at the front end portion of the side plate 212 via the cylinder 41 and the bracket 43. The magnet unit 44 includes a plurality of magnets 44a (first magnets) and a plurality of magnets 44b (second magnets). The plurality of magnets 44a are arranged in the up-down direction. The plurality of magnets 44b are arranged in the up-down direction and are provided alongside the plurality of magnets 44a in the lateral direction.

Each magnet 44b is provided so as to straddle two magnets 44a adjacent to each other in the up-down direction among the plurality of magnets 44a. In other words, each magnet 44b is provided at a position overlapping a missing portion 44c between two magnets 44a adjacent to each other in the up-down direction among the plurality of magnets 44a when viewed from the lateral direction. The missing portion 44c is a portion where no magnet 44a is provided in the array of the plurality of magnets 44a.

Each magnet 44a is provided so as to straddle two magnets 44b adjacent to each other in the up-down direction among the plurality of magnets 44b. In other words, each magnet 44a is provided at a position overlapping a missing portion 44d between two magnets 44b adjacent to each other in the up-down direction among the plurality of magnets 44b when viewed from the lateral direction. The missing portion 44d is a portion where no magnet 44b is provided in the array of the plurality of magnets 44b.

A cover for wear prevention may be provided on a surface of each of the magnets 44a and 44b. The cover is made of, for example, a stainless steel plate. The provision of the cover facilitates removal of the shot media that has adhered to the magnet unit 44 during maintenance.

The liner 45 is a wear-resistant steel plate extending in the up-down direction. Examples of a constituent material of the liner 45 include high manganese steel and high chromium steel. The magnet unit 44 and the liner 45 may be curved to conform to the outer surface Wa of the workpiece W.

The roller 47 is a member for positioning the magnet unit 44 with respect to the outer surface Wa of the workpiece W. In the present embodiment, the side seal structure 40 includes two rollers 47. The two rollers 47 are provided so as to be spaced apart from each other in the up-down direction. An upper roller 47 is provided above the magnet unit 44, and a lower roller 47 is provided below the magnet unit 44. Front ends of the two rollers 47 are provided at substantially the same position in the front-rear direction. The front ends of the two rollers 47 are located in front of the magnets 44a and 44b.

The cylinder 41 advances and retracts the magnet unit 44 with respect to the outer surface Wa. When the magnet unit 44 is advanced toward the outer surface Wa by the cylinder 41 and the front ends of the rollers 47 come into contact with the outer surface Wa, the forward movement of the side seal structure 40 is stopped. As a result, a gap 48 (see FIG. 13) is formed between the magnet unit 44 and the outer surface Wa.

As shown in FIG. 13, shot media M in the projection chamber 21a may enter the gap 48. At this time, in the gap 48, the shot media M is attracted to the magnet unit 44, and the shot media M deposits on the surface of the magnet unit 44. A distance Dm between the magnet unit 44 and the outer surface Wa is set to a length over which a magnetic force (attractive force) of the magnet unit 44 acts. As a result, a layer of the shot media M is formed in the gap 48, whereby the gap 48 is occluded by the shot media M. Once the layer of the shot media M is formed, the possibility that the shot media M leaks to the outside of the projection chamber 21a through the gap 48 is reduced.

Next, the lower seal structure 50 will be described in detail with reference to FIGS. 14 and 15. FIG. 14 is a diagram showing a lower seal structure included in the seal structure shown in FIG. 6. FIG. 15 is a cross-sectional view taken along line XV-XV of FIG. 14.

As shown in FIGS. 14 and 15, the lower seal structure 50 is provided along a lower edge portion extending in the lateral direction of the opening edge of the opening 21b. The lower edge portion of the opening edge of the opening 21b corresponds to the front end portion of the front inclined plate 214. The lower seal structure 50 includes a plurality of cylinders 51, a plurality of guide members 52, a plurality of brackets 53, a plurality of brushes 54, and an elastic member 55.

In the present embodiment, the lower seal structure 50 includes three cylinders 51. The three cylinders 51 are installed on an outer surface of the inclined plate 214 and are arranged in the lateral direction. The lower seal structure 50 includes the same number of guide members 52 as the cylinders 51. One guide member 52 is provided for each cylinder 51 and is disposed laterally alongside the corresponding cylinder 51. Each cylinder 51 is arranged so that a piston rod is advanceable and retractable in the front-rear direction. Each guide member 52 is arranged so that a guide rod is advanceable and retractable in the front-rear direction. One bracket 53 is commonly attached to a tip of the piston rod of the cylinder 51 and a tip of the guide rod of the guide member 52 corresponding to the cylinder 51. As a result, the guide rod of the guide member 52 advances and retracts in conjunction with the advance and retract of the piston rod of the corresponding cylinder 51.

One brush 54 is fixed to each bracket 53. In other words, the brush 54 is provided for each bracket 53. Specifically, a base end of the brush 54 is fixed to the bracket 53 so as to be rotatable around an axis extending in a normal direction of the outer surface of the inclined plate 214, and bristles of the brush 54 extend forward from the base end.

One elastic member 55 is provided at the front end portion of the inclined plate 214. The elastic member 55 is provided at the front end portion of the inclined plate 214 over the entire length of the inclined plate 214 in the lateral direction. The elastic member 55 is a plate material that protrudes forward (toward the outer surface Wa of the workpiece W) from the front end portion of the inclined plate 214. The elastic member 55 is a wear-resistant rubber and has flexibility. Examples of a constituent material of the elastic member 55 include butadiene rubber, styrene-butadiene rubber, urethane rubber, nitrile rubber, and ethylene propylene rubber. A base end of the elastic member 55 is fixed to the outer surface of the inclined plate 214, and a tip of the elastic member 55 is a free end. The elastic member 55 is provided downstream of the brush 54 in the rotation direction of the workpiece W. In other words, the brush 54 is located on the outer side of the cabinet 21 relative to the elastic member 55.

A seal structure similar to the lower seal structure 50 is also provided at a front end portion of an inclined plate of the receiving member 23 that covers the front inclined plate 214. A brush is provided at a front end portion of a side plate of the receiving member 23 that covers the side plate 212 (see FIG. 8). A base end of the brush is fixed to an outer surface of the side plate of the receiving member 23. The brush extends so as to be inclined toward the side plate 212 as it advances forward from the base end.

Next, a shot processing method performed by the control device 17 will be described with reference to FIGS. 16 to 22. FIG. 16 is a flowchart showing a shot processing method performed by the control device shown in FIG. 1. FIG. 17 is a flowchart showing the attitude control of FIG. 16 in detail. FIG. 18 is a diagram for explaining a processing area of the workpiece shown in FIG. 1. FIG. 19 is a diagram for explaining an initial position of the projection device shown in FIG. 6. FIG. 20 is a diagram for explaining a measurement position of the projection device shown in FIG. 6. FIG. 21 is a diagram for explaining tilting of the projection device shown in FIG. 6. FIG. 22 is a diagram for explaining a target position of the projection device shown in FIG. 6.

The shot processing method shown in FIG. 16 is started, for example, in response to an operator performing a shot processing start operation after the workpiece W is set in the rotation mechanism 100. As shown in FIG. 18, the outer surface Wa of the workpiece W is divided into a plurality of processing areas (in this example, processing areas R1 to R7) for each range in which the projection device 12 can perform shot processing in the lateral direction.

As shown in FIG. 19, the projection device 12 is moved to an initial position in the front-rear direction with respect to a target area selected from among the processing areas R1 to R7, and an inclination of the projection device 12 is set to an initial inclination. In this example, since shot processing is performed sequentially from the processing area R1 (first processing area) to the processing area R7, the processing area R1 is first selected as the target area. The initial position is a position where the opening 21b is sufficiently separated from the outer surface Wa. The initial inclination can be set, for example, by a rotation angle sensor provided on the rotary shaft 24. The initial inclination is set, for example, to an inclination of the projection device 12 such that a direction of the opening 21b is orthogonal to a normal direction of the floor surface and the axis AX1. In the following description, the initial position and the initial inclination may be collectively referred to as an “initial attitude”.

First, the control device 17 causes the rotation mechanism 100 to start rotating the workpiece W (step S1). Specifically, when the above-described initial setting is completed, the control device 17 transmits a rotation command to the rotation mechanism 100. Then, upon receiving the rotation command from the control device 17, the rotation mechanism 100 rotates the workpiece W by rotating the turning rolls 102. Then, the rotation mechanism 100 transmits a response indicating that rotation has started to the control device 17.

Subsequently, upon receiving the response from the rotation mechanism 100, the control device 17 performs attitude control (step S2). As shown in FIG. 17, in the attitude control, first, the control device 17 moves the projection device 12 to a measurement position (step S21). As shown in FIG. 20, the measurement position is a position for measuring the distance to the outer surface Wa, and is separated from the outer surface Wa by a preset distance (measurement distance). The measurement distance is set within a range in which the projection device 12 does not interfere with any workpiece W having any diameter. The control device 17 controls the moving mechanism 15 to move the projection device 12 from the initial position to the measurement position. During the movement from the initial position to the measurement position, the distance sensors 26a to 26d measure the distance and transmit the measured values to the control device 17.

Subsequently, the control device 17 determines a sensor set to be used for the attitude control (step S22). For example, the control device 17 determines, as the sensor set to be used for the attitude control, the sensor set including the distance sensor that first measured the measurement distance among the distance sensors 26a to 26d. For example, when the workpiece W has a tapered shape, the sensor set disposed on a large-diameter side of the workpiece W is used. Here, it is assumed that the sensor set of the distance sensor 26a and the distance sensor 26b is used for the attitude control.

Subsequently, the control device 17 tilts the projection device 12 (step S23). In step S23, as shown in FIG. 21, the control device 17 controls the tilting mechanism 16 to tilt the projection device 12 such that a difference (absolute value of the difference) between a distance L1 (first distance) measured by the distance sensor 26a and a distance L2 (second distance) measured by the distance sensor 26b becomes smaller than a tilt threshold. The tilt threshold is preset. The tilt threshold is, for example, 5 mm.

Subsequently, the control device 17 moves the projection device 12 to a target position (step S24). As shown in FIG. 22, the target position is a position where the projection device 12 performs projection, and is separated from the outer surface Wa by a preset distance (target distance). The target distance is set to a distance at which leakage of shot is minimized within a range in which the cabinet 21 does not contact the outer surface Wa. The control device 17 controls the moving mechanism 15 to advance the projection device 12 until the distance L1 or the distance L2 becomes the target distance.

Subsequently, the control device 17 determines whether an attitude condition is satisfied (step S25). The attitude condition is a condition that the difference between the distance L1 and the distance L2 is smaller than the tilt threshold, and that the distance L1 and the distance L2 are included within a target range. The target range is a range including the target distance. A lower limit value of the target range is, for example, a value obtained by subtracting a distance threshold from the target distance, and an upper limit value of the target range is, for example, a value obtained by adding the distance threshold to the target distance. The distance threshold is preset. The distance threshold is, for example, 5 mm. For example, in step S24, when the projection device 12 advances from the measurement position toward the target position, the difference between the distance L1 and the distance L2 may increase due to factors such as a change in the position of the outer surface Wa measured by the distance sensors 26a and 26b. In such a case, the attitude condition is not satisfied.

In step S25, when it is determined that the attitude condition is not satisfied (step S25: NO), the control device 17 performs steps S23 to S25 again. On the other hand, in step S25, when it is determined that the attitude condition is satisfied (step S25: YES), the control device 17 ends the attitude control.

As described above, the control device 17 performs the attitude control using the first sensor set of the distance sensor 26a and the distance sensor 26b or the second sensor set of the distance sensor 26c and the distance sensor 26d. When using the first sensor set, the control device 17 performs the attitude control based on the distance L1 and the distance L2. Specifically, the control device 17 controls the moving mechanism 15 and the tilting mechanism 16 to tilt the projection device 12 such that the difference between the distance L1 and the distance L2 becomes smaller than the tilt threshold, and to move the projection device 12 in the front-rear direction such that the distance L1 and the distance L2 fall within the target range.

When using the second sensor set, the control device 17 performs the attitude control based on a distance L3 measured by the distance sensor 26c and a distance L4 measured by the distance sensor 26d. Specifically, the control device 17 controls the moving mechanism 15 and the tilting mechanism 16 to tilt the projection device 12 such that a difference between the distance L3 and the distance L4 becomes smaller than the tilt threshold, and to move the projection device 12 in the front-rear direction such that the distance L3 and the distance L4 fall within the target range.

Subsequently, the control device 17 presses the seal structure 25 against the outer surface Wa (step S3). In step S3, the control device 17 controls each cylinder 31 to advance the piston rod until a tip of the elastic member 36 comes into contact with the outer surface Wa. The control device 17 controls the cylinder 41 to advance the piston rod until the pair of rollers 47 come into contact with the outer surface Wa. Similarly, the control device 17 controls each cylinder 51 to advance the piston rod until a tip of the brush 54 comes into contact with the outer surface Wa. The advance of the piston rod is stopped when a pressure received by the piston rod reaches a set pressure.

In other words, once the attitude of the projection device 12 (cabinet 21) with respect to the outer surface Wa of the workpiece W has been adjusted, each cylinder 31 presses the elastic member 36 against the outer surface Wa. Once the attitude of the projection device 12 (cabinet 21) with respect to the outer surface Wa of the workpiece W has been adjusted, the cylinder 41 moves the magnet unit 44 toward the outer surface Wa. Once the attitude of the projection device 12 (cabinet 21) with respect to the outer surface Wa of the workpiece W has been adjusted, each cylinder 51 presses the brush 54 against the outer surface Wa.

Subsequently, the control device 17 starts projection (step S4). In step S4, the control device 17 controls a drive unit (not shown) of the projector 22 to cause the projector 22 to project the shot media. A projection amount and a projection speed are preset. The projection amount and the projection speed may be set based on workpiece information regarding the workpiece W input by an operator. The workpiece information may be input from a higher-level tool such as computer aided design (CAD). In the second and subsequent processing areas, the control device 17 may change the processing conditions of the shot processing in accordance with the inspection result by the inspection device 28 in the immediately preceding processing area.

Subsequently, the control device 17 determines whether a stop condition is satisfied (step S5). The stop condition is a condition for stopping the shot processing for the target area. As the stop condition, for example, the fact that the workpiece W has rotated once around the axis AX1 is used. One rotation of the workpiece W is detected, for example, by the rotation angle sensor provided in the rotation mechanism 100. As the stop condition, the fact that the processing of the target area satisfies the required specifications of the shot processing based on the inspection result by the inspection device 28 may be used.

In step S5, when it is determined that the stop condition is not satisfied (step S5: NO), the control device 17 repeats the determination of step S5 until the stop condition is satisfied. During this time, projection is continued. On the other hand, in step S5, when it is determined that the stop condition is satisfied (step S5: YES), the control device 17 stops the projection (step S6). In step S6, the control device 17 controls the drive unit (not shown) of the projector 22 to stop the projector 22.

Subsequently, the control device 17 releases the pressing of the seal structure 25 (step S7). In step S7, the control device 17 controls each cylinder 31, the cylinder 41, and each cylinder 51 to retract the tip of the piston rod to its original position.

Subsequently, the control device 17 returns the attitude of the projection device 12 to the initial attitude (step S8). In step S8, the control device 17 controls the moving mechanism 15 to return the projection device 12 to the initial position, and controls the tilting mechanism 16 to return the projection device 12 to the initial inclination.

Subsequently, the control device 17 determines whether an end condition is satisfied (step S9). The end condition is a condition for ending the shot processing for the workpiece W. As the end condition, for example, the fact that the shot processing for all the processing areas R1 to R7 has been completed is used.

In step S9, when it is determined that the end condition is not satisfied (step S9: NO), the control device 17 controls the moving mechanism 15 to move the projection device 12 in the lateral direction (step S10), and selects the next processing area as the target area. For example, in response to the completion of the shot processing of the processing area R1, the control device 17 controls the moving mechanism 15 to move the projection device 12 to the processing area R2 (second processing area) adjacent to the processing area R1. Then, the control device 17 performs steps S2 to S9 again. On the other hand, in step S9, when it is determined that the end condition is satisfied (step S9: YES), the shot processing method ends.

In the shot processing device 10 described above, the magnet unit 44 is provided along the side edge portion extending in the up-down direction of the opening edge of the opening 21b of the cabinet 21. According to this configuration, even if a gap 48 is formed between the magnet unit 44 and the outer surface Wa of the workpiece W, the shot media is attracted to the magnet unit 44 in the gap 48, and the shot media deposits on the surface of the magnet unit 44. Accordingly, the gap 48 is occluded by the shot media, thereby reducing the possibility that particulate matter including the shot media leaks to the outside of the projection chamber 21a through the gap 48. As a result, leakage of particulate matter can be suppressed.

The brush 46 is provided on the outer side of the cabinet 21 relative to the magnet unit 44. Since a labyrinth structure is formed by the bristles of the brush 46, even if particulate matter passes through the gap 48, the possibility that the particulate matter leaks to the outside of the projection chamber 21a is reduced by the brush 46. As a result, leakage of particulate matter can be further suppressed. Even if the particulate matter passes through the brush 46, its speed is reduced by the side seal structure 40, so the scattering range of the particulate matter can be narrowed.

The brush 46 is inclined toward a front of the magnet unit 44. For this reason, the shot media occluding the gap 48 is more likely to be retained in the gap 48 by a tip of the brush 46. For example, even if the shot media enters the gap 48 from the projection chamber 21a at high speed, the possibility that the layer of the shot media collapses is reduced. Therefore, the possibility that particulate matter including the shot media leaks to the outside of the projection chamber 21a through the gap 48 is reduced. As a result, leakage of particulate matter can be suppressed.

Between two adjacent magnets 44a, the missing portion 44c where no magnet 44a is provided is formed, and shot media is less likely to deposit in the missing portion 44c. In the shot processing device 10, since the magnet 44b is provided at a position overlapping the missing portion 44c in the lateral direction, the shot media that has passed through the missing portion 44c is attracted to the magnet 44b and deposits on the surface of the magnet 44b in a gap between the magnet 44b and the outer surface Wa. As a result, the gap between the magnet 44b and the outer surface Wa is occluded. Therefore, leakage of particulate matter can be further suppressed.

The position of the magnet unit 44 with respect to the outer surface Wa of the workpiece W is determined by the two rollers 47. According to this configuration, the distance Dm between the magnet unit 44 and the outer surface Wa is set, and the gap 48 is formed. By setting the distance Dm to a distance over which the magnetic force of the magnet unit 44 acts, the gap 48 can be more reliably occluded by the shot media. As a result, leakage of particulate matter can be further suppressed. Even if the shape of the gap 48 changes due to a difference in the shape (diameter) of the workpiece W, the gap 48 can be occluded by the shot media.

In a configuration that prevents leakage of particulate matter by bringing an elastic member into contact with the outer surface Wa, the elastic member wears due to the rotation of the workpiece W. In contrast, in the side seal structure 40, the gap 48 is filled with shot media without the magnet unit 44 contacting the outer surface Wa, so replacement of the magnet unit 44 due to wear is unnecessary.

The magnet unit 44 is moved toward the outer surface Wa after the attitude of the projection device 12 (cabinet 21) with respect to the outer surface Wa of the workpiece W is adjusted. According to this configuration, variation in the distance Dm can be reduced. Therefore, the gap 48 can be more reliably occluded by the shot media. As a result, leakage of particulate matter can be further suppressed.

The shot processing device according to the present disclosure is not limited to the above embodiments.

For example, the moving mechanism 15 may be any mechanism that can relatively move the projection device 12 with respect to the workpiece W in the front-rear direction and the lateral direction. The moving mechanism 15 may move the rotation mechanism 100 (workpiece W) instead of moving the supply device 11, the projection device 12, the collection device 13, the classification device 14, and the tilting mechanism 16.

The length of the opening 21b in the lateral direction may be equal to or greater than the length of the workpiece W along the axis AX1. In this case, the moving mechanism 15 does not have to relatively move the projection device 12 in the lateral direction.

The projection device 12 is not required to include both the first sensor set of the distance sensors 26a and 26b and the second sensor set of the distance sensors 26c and 26d.

The projection device 12 is not required to include the foreign object detection device 27. The projection device 12 is not required to include the inspection device 28.

The workpiece information may include information such as a projection position, an outer diameter of the workpiece W at the projection position, an entire length of the workpiece W, and an incident angle of the shot media projected onto the outer surface Wa. The control device 17 may set the target position such that the incident angle of the shot media projected from the projector 22 onto the outer surface Wa matches the incident angle included in the workpiece information.

The control device 17 may change a supply amount of the shot media based on the measured values of the distance sensors 26a to 26d. For example, the control device 17 increases the supply amount of the shot media when the distances L1 to L4 are long, and decreases the supply amount of the shot media when the distances L1 to L4 are short. As a result, uniformity of the finish can be achieved, and excessive quality or failure to meet quality standards can be avoided.

The control device 17 may adjust the inclination of the projection device 12 by pressing the opening 21b against the outer surface Wa instead of performing tilting control. In this case, the projection device 12 is not required to include the distance sensors 26a to 26d.

If the piston rod can be advanced and retracted, each seal structure is not required to include a guide member.

The upper seal structure 30 is not required to include the elastic body 35. Even in this case, the possibility that the particulate matter leaks to the outside of the projection chamber 21a is reduced by the brush 34. The upper seal structure 30 is not required to include the brush 34. Even in this case, the possibility that the particulate matter leaks to the outside of the projection chamber 21a is reduced by the elastic member 36.

The plurality of brushes 34 may be integrated to form one brush.

The side seal structure 40 is not required to include the liner 45. The side seal structure 40 is not required to include the brush 46. Even in this case, the possibility that the particulate matter leaks to the outside of the projection chamber 21a is reduced by the magnet unit 44.

For example, a desired gap 48 may be obtained by the attitude control. In this case, the side seal structure 40 is not required to include the cylinder 41, the guide member 42, and the roller 47.

At least one of the upper seal structure 30 and the lower seal structure 50 may have a configuration similar to that of the side seal structure 40. That is, at least one of the upper seal structure 30 and the lower seal structure 50 may include a magnet unit and may be configured to fill a gap between the magnet unit and the outer surface Wa with shot media.

The attitude control is not limited to the attitude control of the above embodiments. For example, the projection device 12 may include four limit switches provided at four corners of the opening 21b instead of or in addition to the distance sensors 26a to 26d, and the control device 17 may perform the attitude control using these limit switches.

Specifically, the control device 17 first controls the moving mechanism 15 to advance the projection device 12 until an upper limit switch is switched from an OFF state to an ON state. Then, the control device 17 controls the tilting mechanism 16 to tilt the projection device 12 until a lower limit switch is switched from an OFF state to an ON state. At this time, the control device 17 measures, with a timer (not shown), a time from when the upper limit switch is switched from the ON state to the OFF state to when the lower limit switch is switched from the OFF state to the ON state.

Then, the control device 17 controls the tilting mechanism 16 to tilt the tilting of the projection device 12 back toward the original direction for a period equal to half of the measured time. As a result, the upper and lower limit switches are turned OFF, so the control device 17 controls the moving mechanism 15 to advance the projection device 12. When both the upper and lower limit switches are switched to the ON state, it is regarded that the opening 21b is along the outer surface Wa, so the control device 17 ends the attitude control. On the other hand, when at least one of the upper and lower limit switches fails to be switched to the ON state, the control device 17 repeats the foregoing sequence until both the upper and lower limit switches are switched to the ON state.

The projection device 12 may include a distance sensor provided at an upper stage of the cabinet 21, a distance sensor provided at a middle stage of the cabinet 21, and a distance sensor provided at a lower stage of the cabinet 21, instead of or in addition to the distance sensors 26a to 26d, and the control device 17 may perform the attitude control using distances measured by these distance sensors. Each distance sensor measures a distance to the outer surface Wa via the opening 21b.

Specifically, the control device 17 calculates a radius of the workpiece W by deriving a curve connecting the distances measured by these distance sensors. Then, the control device 17 controls the tilting mechanism 16 to tilt the projection device 12 to an angle along the calculated radius. Then, the control device 17 controls the moving mechanism 15 to advance the projection device 12 to the target position, and ends the attitude control.

The present disclosure includes the forms described in the following clauses.

Clause 1

A shot processing device that performs shot processing on an outer surface of a cylindrical workpiece, the shot processing device comprising:

• • a cabinet defining a projection chamber, the cabinet including an opening that communicates with the projection chamber and opens toward the outer surface of the workpiece;
  • a projector provided in the cabinet and configured to project shot media toward the outer surface of the workpiece via the opening; and
  • a seal structure provided along an opening edge of the opening,
  • wherein the seal structure comprises a magnet unit provided on a portion of the opening edge, the portion extending in a first direction intersecting a central axis of the workpiece.

Clause 2

The shot processing device according to clause 1,

• • wherein the seal structure further comprises a brush located on an outer side of the cabinet relative to the magnet unit.

Clause 3

The shot processing device according to clause 2,

• • wherein the brush is inclined toward a front of the magnet unit.

Clause 4

The shot processing device according to any one of clauses 1 to 3,

• • wherein the magnet unit comprises:
    • a plurality of first magnets arranged in the first direction; and
    • a second magnet provided alongside the plurality of first magnets in a second direction along the central axis of the workpiece,
  • wherein the second magnet is provided at a position overlapping a missing portion between two adjacent first magnets of the plurality of first magnets when viewed from the second direction.

Clause 5

The shot processing device according to any one of clauses 1 to 4,

• • wherein the seal structure further comprises:
    • a drive unit configured to advance and retract the magnet unit with respect to the outer surface of the workpiece; and
    • a positioning member provided on the magnet unit and configured to determine a position of the magnet unit with respect to the outer surface of the workpiece.

Clause 6

The shot processing device according to clause 5,

• • wherein the drive unit moves the magnet unit toward the outer surface of the workpiece after an attitude of the cabinet with respect to the outer surface of the workpiece is adjusted.

In the shot processing device according to clause 1, the magnet unit is provided on the portion of the opening edge of the opening of the cabinet, the portion extending in the first direction intersecting the central axis of the workpiece. According to this configuration, even if a gap is formed between the magnet unit and the outer surface of the workpiece, the shot media is attracted to the magnet unit in the gap, and the shot media deposits on the surface of the magnet unit. Accordingly, the gap is occluded by the shot media, thereby reducing the possibility that particulate matter including the shot media leaks to the outside of the projection chamber through the gap. As a result, leakage of particulate matter can be suppressed.

In the shot processing device according to clause 2, a labyrinth structure is formed by the bristles of the brush. Therefore, even if particulate matter passes through the gap between the magnet unit and the outer surface of the workpiece, the possibility that the particulate matter leaks to the outside of the projection chamber is reduced by the brush. As a result, leakage of particulate matter can be further suppressed.

In the shot processing device according to clause 3, the brush is inclined toward the front of the magnet unit. For this reason, the shot media occluding the gap between the magnet unit and the outer surface of the workpiece is more likely to be retained in the gap by a tip of the brush. Therefore, the possibility that particulate matter including the shot media leaks to the outside of the projection chamber through the gap is reduced. As a result, leakage of particulate matter can be suppressed.

In the shot processing device according to clause 4, the second magnet is provided at a position overlapping a missing portion between two adjacent first magnets of the plurality of first magnets when viewed from the second direction. According to this configuration, the shot media that has passed through the missing portion is attracted to and deposits on the second magnet in a gap between the second magnet and the outer surface of the workpiece. As a result, the gap between the second magnet and the outer surface of the workpiece is occluded. Therefore, leakage of particulate matter can be further suppressed.

In the shot processing device according to clause 5, a distance between the magnet unit and the outer surface of the workpiece is defined by the positioning member, and a gap is formed. By setting the distance between the magnet unit and the outer surface of the workpiece to a distance over which the magnetic force of the magnet unit acts, the gap can be more reliably occluded by the shot media. As a result, leakage of particulate matter can be further suppressed.

In the shot processing device according to clause 6, the magnet unit is moved toward the outer surface of the workpiece after the attitude of the cabinet with respect to the outer surface of the workpiece is adjusted. According to this configuration, variation in the distance between the magnet unit and the outer surface of the workpiece can be reduced. Therefore, the gap can be more reliably occluded by the shot media. As a result, leakage of particulate matter can be further suppressed.