FIXED STRUCTURE, FIXING METHOD, AND FIXING DEVICE

Description

TECHNICAL FIELD

The present invention relates to a structure in which a plurality of members are fixed, a method of anchoring a plurality of members, and an anchoring device.

BACKGROUND ART

A caulking structure using a rivet or the like has been known as a method of fixing a plurality of members in the related art. The structure fixed by the caulking structure with the rivet is a structure in which the head portions of both ends of the rivet protrude from the surface of the structure. The head portion of the protruding rivet may cause inconvenience in the structure.

For example, in a case where a flat surface portion of a heat sink needs to be in close contact with a flat surface portion of a member to be cooled, in a case where a head portion of a rivet protrudes from the flat surface portion of the heat sink, the head portion cannot be brought into close contact with the flat surface portion of the member to be cooled.

Therefore, a method of forming a plurality of bosses on one surface of a base portion of a heat sink, inserting the bosses into a plurality of boss holes formed in a heat dissipation plate, and caulking the bosses to fix the base portion and the heat dissipation portion without forming a protruding portion on the other surface of the base portion has been proposed (PTL 1).

In addition, in a caulking structure with a rivet, a method has also been proposed in which a recessed portion is formed on a surface of a structural body so that a head portion of the rivet does not protrude from the structural body, and the structural body is caulked with a rivet having a bowl-shaped head that fits into the recessed portion so that the protruding portion is not formed (PTL 2).

CITATION LIST

Patent Literature

• • [PTL 1] JP2018-77995A
  • [PTL 2] JP2009-115314A

SUMMARY OF INVENTION

Technical Problem

In the fixing method proposed in PTL 1, a flat surface without a protruding portion can be held, but it is necessary to manufacture a base portion having a plurality of bosses. There is a problem in that it is not easy to manufacture the base portion having the plurality of bosses and a large cost is required.

In addition, in the fixing method proposed in PTL 2, although a plane without a protruding portion can be held, there is a problem in that a highly accurate plane cannot be held because there is a manufacturing error in a recessed portion or a bowl- shaped head on the surface of the structure and unevenness occurs in a storage portion of the bowl-shaped head. In addition, there is a problem that a large cost is required for manufacturing a rivet having a bowl-shaped head.

Therefore, an object of the present invention is to provide a fixed structure, a fixing method, and a fixing device that can solve the above-described problem, maintain a high-accuracy flat surface, and reduce a manufacturing cost.

Solution to Problem

In order to solve such problems, the present invention comprises the following configurations.

A structure in which a plurality of members including at least a first member are fixed, in which

• • a first through-hole is provided in the first member,
  • a caulked body is inserted into the first through-hole,
  • a first opening portion that is open to one flat surface portion of the first member is formed at one end of the first through-hole,
  • a first recessed portion is provided in the one flat surface portion of the first member to surround the first opening portion,
  • a first head portion at one end of the caulked body is stored in the first recessed portion, and
  • the one flat surface portion of the first member and the first head portion are flush with each other.

In addition, the present invention has the following configurations.

A fixing method of fixing a plurality of members, the fixing method comprising:

• • a step of overlapping the plurality of members such that through-holes provided in the plurality of members coincide with each other;
  • a step of inserting a caulked body into the through-holes of the coinciding plurality of members; and
  • a step of caulking both ends of the caulked body at the same time.

In addition, the present invention has the following configurations.

A fixing device for fixing a plurality of members, the device comprising a punch, a stripper, a die, and a die pin, wherein

• • a caulked body is inserted into a through-hole penetrating the plurality of members,
  • the punch abuts one end of the caulked body,
  • the stripper abuts one flat surface portion of the plurality of members,
  • the die abuts the other flat surface portion of the plurality of members,
  • the die pin abuts the other end of the caulked body, and
  • the punch, the stripper, the die, and/or the die pin are moved such that both ends of the caulked body are simultaneously caulked.

Advantageous Effects of Invention

By housing the head portion of the caulked body in the recessed portion formed on the surface of the structure to be fixed, a flat surface with high accuracy can be maintained, and by using the caulked body that is caulked at both ends at the same time, it is possible to provide a fixed structure, a fixing method, and a fixing device that can reduce the manufacturing cost.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view of a structure 1 of the first embodiment of the present invention, in which (a) shows a view before caulking and (b) shows a view after caulking.

FIG. 2 is a view showing a part of a caulking step of caulking a structure 1 of the first embodiment of the present invention with a press machine 2.

FIG. 3 is a view showing a remainder of a caulking step of caulking the structure 1 of the first embodiment of the present invention with a press machine 2.

FIG. 4 is a graph showing movement of each component of the press machine 2 in a caulking step of the first embodiment of the present invention.

FIG. 5 is a perspective image of a cut structure 1 according to the first embodiment of the present invention.

FIG. 6 is a perspective image of a cut structure 1 according to another example of the embodiment 1 of the present invention.

FIG. 7 is a view of a structure 3 of the second embodiment of the present invention, in which (a) shows a view before caulking and (b) shows a view after caulking.

FIG. 8 is a view showing a part of a caulking step of caulking the structure 3 of the second embodiment of the present invention with a press machine 2′.

FIG. 9 is a view of a structure 4 of Modification Example 2 of the present invention, in which (a) shows a view before caulking and (b) shows a view after caulking.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a structure 1 according to an embodiment of the present invention will be described with reference to the drawings.

In the following description, the same reference numerals in different figures denote the parts having the same functions, and the duplicated description thereof will be omitted as appropriate.

First embodiment

FIG. 1 is a view of a structure 1 of the first embodiment of the present invention, in which (a) shows a view before caulking and (b) shows a view after caulking.

Configuration of Each Member

The structure 1 of the first embodiment is composed of three metal members, that is, a base material 11 (first member), a U-shaped material 12 (second member), and a rod 13 (caulked body).

The structure 1 is a heat sink, and the base material 11 is brought into contact with a surface of a member to be cooled, and heat is released from the base material 11 and the U-shaped material 12 to the air.

The base material 11 is a rectangular plate-like member formed of aluminum, and has a base portion 111 and a columnar protrusion portion 112 (protrusion portion) that is provided to protrude from a center portion of one surface 1111 (other flat surface portion of the first member) of the base portion 111.

A circular through-hole 113 (first through-hole) through which the rod 13 can be inserted is formed in the base material 11 so as to be concentric with the protrusion portion 112. The protrusion portion 112 has one opening portion (second opening portion) of the through-hole 113, and the other opening portion (first opening portion) of the through-hole 113 is provided on the other surface 1112 (one flat surface portion of the first member) of the base portion 111 of the base material 11. A circular recessed portion 114 (first recessed portion) that is concentric with the through-hole 113 and has a diameter larger than the diameter of the through-hole 113 is formed around the other opening portion of the through-hole 113. As will be described later, the recessed portion 114 is formed as a notch for accommodating a head portion 1311 (first head portion) of the lower end portion 131 formed when the rod 13 is caulked, and the radius and the depth are designed so that the head portion 1311 of the lower end portion 131 can be accommodated without excess or deficiency.

The U-shaped material 12 is a member formed of aluminum, and is a rectangular plate material that is bent such that a cross section thereof is U-shaped, and comprises a base portion 121 and bending portions 122 (erecting portions). The bending portions 122 are not limited to a shape that is bent at a right angle, and may have a shape that forms a curved surface.

An annular fitting hole 123 (fitting portion) that can be fitted to the protrusion portion 112 of the base material 11 is formed in the base portion 121 of the U-shaped material 12. In addition, the height of the fitting hole 123 is substantially the same as the height of the protrusion portion 112. The inner diameter of the fitting hole 123 is substantially the same as the outer diameter of the protrusion portion 112 of the base material 11, and the fitting hole 123 can be fitted to the protrusion portion 112 without a gap.

The rod 13 is a column formed of aluminum and is formed to be longer than a length obtained by adding a length of the through-hole 113 and a depth of the recessed portion 114. In addition, the diameter of the rod 13 is substantially the same as the diameter of the through-hole 113 of the base material 11, and the rod 13 can be inserted into the through-hole 113 without a gap.

Structure After Caulking

The fitting hole 123 of the U-shaped material 12 is fitted to the protrusion portion 112 of the base material 11, the rod 13 is inserted into the through-hole 113 of the base material 11, and the rod 13 is pressed and caulked simultaneously from above and below by the press machine 2. The obtained structure 1 is shown in FIG. 1(b).

The lower end portion 131 of the rod 13 is formed into a head portion 1311 that is caulked and stored in the recessed portion 114 of the base material 11 with substantially no gap.

The head portion 1311 and the other surface 1112 of the base material 11 are flush with each other.

The head portion 1311 and the recessed portion 114 of the base material 11 are in contact with each other in a strongly pressure-bonded state by pressing and caulking the rod 13.

The upper end portion 132 of the rod 13 is caulked and is formed into a substantially truncated conical shape together with the protrusion portion 112 of the base material 11 and the fitting hole 123 of the U-shaped material 12.

This substantially truncated conical portion has a larger diameter than the original through-hole 113, and the rod 13 does not come out of the through-hole 113 together with the head portion 1311 of the rod 13. In addition, the substantially truncated conical shape prevents the fitting hole 123 of the U-shaped material 12 from being disengaged from the protrusion portion 112 of the base material 11.

In addition, the rod 13 that has been pressed and caulked from above and below is deformed into a substantially barrel shape in which the vicinity of the center portion in the length direction (between the substantially truncated conical portion and the head portion 1311) is swollen. Due to the shape of the truncated barrel shape itself and the firm adhesion between the peripheral surface of the rod 13 and the inner peripheral surface of the through-hole 113, the rod 13 does not come out vertically.

FIG. 5 shows a perspective image of the cut and deformed structure after caulking.

The base material 11 is not limited to a rectangular shape, and any shape can be selected depending on the application.

The U-shaped material 12 is not limited to a rectangular shape before being bent in a U-shaped cross section, and any shape can be selected depending on the use application.

In addition, the height of the fitting hole 123 of the U-shaped material 12 does not need to be substantially the same as the height of the protrusion portion 112 of the base material 11, may be lower than the height of the protrusion portion 112, and may be the same as the thickness of the base portion 121 of the U-shaped material 12. In addition, the height of the fitting hole 123 may be slightly higher than the height of the protrusion portion 112.

FIG. 6 shows an example in which the height of the fitting hole 123 is the same as the thickness of the base portion 121.

The base material 11, the U-shaped material 12, and the rod 13 may be formed of a single metal of a metal other than aluminum, for example, copper or iron, an alloy, or the like.

In addition, it is not necessary to form the base material 11, the U-shaped material 12, and the rod 13 from the same metal, and one of the three may be formed from a metal different from the other two, or all three may be formed from different metals.

In addition, another member may be disposed between the base material 11 and the U-shaped material 12.

Caulking Device (Fixing Device)

A configuration of a press machine 2, which is a caulking device for caulking the structure 1, will be described with reference to FIG. 2(a).

The press machine 2 includes a die 21 that comes into contact with the base material 11 from below, a stripper 22 that comes into contact with the U-shaped material 12 from above, a die pin 23 that comes into contact with the rod 13 from below, and a punch 24 that comes into contact with the rod 13 from above.

The die 21 is a thick plate-like member, and has an insertion hole 213 into which the die pin 23 can be inserted in the vicinity of the center.

Four die suspension bolts 211 are attached to the die 21.

The die 21 is configured to be lowered by movable means (not shown) together with the die suspension bolt 211.

A die pin backing 231 is installed on the die suspension bolt 211 so as to be slidable up and down. A coil spring 212 is installed concentrically with the die suspension bolt 211 between the die 21 and the die pin backing 231, and the coil spring 212 biases the die 21 and the die pin backing 231 in a direction in which the die 21 and the die pin backing 231 are spaced apart from each other.

The die pin 23 is a rod-like member and is installed between the insertion hole 213 provided in the die 21 and the die pin backing 231. A die damper 232 is disposed around the die pin 23, and when the die 21 is lowered by a predetermined amount, the die 21 comes into contact with the die damper 232.

The stripper 22 is a thick plate-like member and has an insertion hole 223 into which the punch 24 can be inserted in the vicinity of the center. In addition, the stripper 22 includes a protruding portion 224 that protrudes downward from the body portion of the stripper 22 so as to be able to abut on the base portion 121 while avoiding the bending portion 122 of the U-shaped material 12.

Four stripper suspension bolts 221 are attached to the stripper 22.

The stripper 22 is configured to be lowered by movable means (not shown) together with the stripper suspension bolts 221.

A punch backing 241 is installed on the stripper suspension bolts 221 so as to slidable up and down. Coil springs 222 are installed concentrically with the stripper suspension bolts 221 between the stripper 22 and the punch backing 241, and the coil springs 222 bias the stripper 22 and the punch backing 241 in a direction in which the stripper 22 and the punch backing 241 are spaced apart from each other.

The punch 24 is a rod-like member and is installed between the insertion hole 223 provided in the stripper 22 and the punch backing 241.

The punch 24 is configured to be lowered by movable means (not shown) together with the punch backing 241.

A stripper damper 242 is disposed around the punch 24, and when the punch backing 241 is lowered by a predetermined amount, the punch 24 abuts on the stripper damper 242.

Caulking Step (Fixing Method)

FIGS. 2 and 3 are diagrams showing a caulking step of caulking the base material 11, the U-shaped material 12, and the rod 13, and the steps proceed in the order of FIG. 2(a), FIG. 2(b), FIG. 3(c), FIG. 3(d), and FIG. 3(e).

The caulking step is performed by the press machine 2. In the press machine 2, the rod 13 is caulked by moving the die 21, the stripper 22, and the punch 24.

(Step a) An assembly in which the fitting hole 123 of the U-shaped material 12 is fitted to the protrusion portion 112 of the base material 11 and the U-shaped material 12 is superimposed on the base material 11 is placed on the die 21. Next, the rod 13 is inserted into the through-hole 113 of the base material 11, and the lower end portion 131 of the rod 13 is placed on the die pin 23. Then, the stripper 22 and the punch 24 are moved downward, and the protruding portion 224 of the stripper 22 abuts on the base portion 121 of the U-shaped material 12 as shown in FIG. 2(a).

(Step b) The stripper 22 is stopped, and only the punch 24 continues to move downward, and as shown in FIG. 2(b), the punch 24 abuts on the upper end portion 132 of the rod 13.

(Step c) Further, when the punch 24 moves downward, the upper portion of the rod 13 is slightly deformed by being caulked as shown in FIG. 3(a). The die pin 23 is fixed, but the lower end portion 131 of the rod 13 is relatively pressed by the die pin 23 by the movement of the punch 24, and thus the lower portion of the rod 13 is also slightly deformed by being caulked.

(Step d) As shown in FIG. 3(d), when the punch backing 241 comes into contact with the stripper damper 242, the movement of the stripper 22 is restarted, and the stripper 22 moves downward together with the punch 24. At that time, the die 21 also starts moving downward.

The die pin 23 is fixed, but the die 21 and the stripper 22 are also moved in addition to the movement of the punch 24, so that the lower end portion 131 of the rod 13 is relatively more pressed by the die pin 23. By this pressing, the lower portion of the rod 13 is also deformed by being caulked.

In addition, since the punch 24 is also continuously moved, the upper portion of the rod 13 is further caulked by being further deformed.

(Step e) When the die 21 comes into contact with the die damper 232, the downward movement of the die 21, the stripper 22, and the punch 24 is stopped. At that time, the upper surface of the die 21 is flush with the upper surface of the die pin 23.

When the caulking of the rod 13 is completed, as shown in FIG. 3(e), the protrusion portion 112 of the base material 11, the fitting hole 123 of the U-shaped material 12, and the upper portion of the rod 13 are formed in a substantially truncated conical shape. In addition, the lower portion of the rod 13 is also caulked and stored in the recessed portion 114 of the base material 11 formed as a recess. The head portion 1321 of the lower end portion 131 of the rod 13 that is caulked is flush with the other surface 1112 of the base material 11.

The die 21, the stripper 22, and the punch 24 immediately start moving upward after stopping and return to the original positions.

In one cycle of the above-described steps a to e, one structural body 1 is molded, and by repeating this cycle, the structure 1 can be mass-produced.

FIG. 4 is a graph showing changes in positions of the die 21, the protruding portion 224 of the stripper 22, and the punch 24 in one cycle, and (1), (2), and (3) show the positions of the punch 24, the protruding portion 224 of the stripper 22, and the die 21, respectively. In addition, (a), (b), and (e) in the graph respectively indicate the time t at which the state shown in FIG. 3(a), FIG. 3(b), and FIG. 3(e) is obtained.

As described above, the lower end portion 131 of the rod 13 is caulked by the die pin 23, and when the caulking is completed, the upper surface of the die 21 is flush with the upper surface of the die pin 23. Therefore, the head portion 1321 of the lower end portion 131 of the rod 13 that is caulked is formed to be flush with the other surface 1112 of the base material 11 with high accuracy.

Due to this high accuracy of coplanarity, the other surface 1112 of the base material 11 can be brought into contact with a surface of another member such as a member to be cooled without a gap. As a result, thermal conduction resistance at the boundary between the two surfaces is reduced, and the heat dissipation efficiency as a heat sink is improved.

In addition, since the lower end portion 131 of the rod 13 is caulked and stored in the recessed portion 114 of the base material 11, the caulked head portion 1311 of the lower end portion 131 is strongly pressure-bonded to the inner surface of the recessed portion 114 of the base material 11.

Due to the strong pressure bonding, the base material 11 and the rod 13 are firmly anchored, and the thermal conduction resistance at the boundary surface between the base material 11 and the rod 13 is reduced, and the heat dissipation efficiency as a heat sink is increased.

In addition, since the structure 1 can be manufactured only by fixing the base material 11 and the U-shaped material 12 using the rod 13 having a cylindrical shape, the manufacturing cost can be reduced.

In the first embodiment, the rod 13 is pressed from above by the punch 24, and at the same time, the lower end portion 131 is pressed by the die pin 23.

The present invention is not limited thereto, and the lower end portion 131 may be pressed by moving the die pin 23 upward while the die 21 and the stripper 22 are fixed, that is, the rod 13 may be pressed from above by the punch 24, and at the same time, the lower end portion 131 may be directly pressed by the die pin 23.

In any method, the rod 13 is pressed and caulked from both the vertical directions at the same time.

With respect to these, the lower end portion 131 and the upper end portion 132 of the rod 13 can be caulked, that is, the rod 13 can be caulked by pressing only in the upward direction by moving only the punch 24. In addition, the rod 13 can be pressed and caulked only from below by moving the die pin 23. In any method, the rod 13 is pressed and caulked from the up-down direction.

In the method of pressing and caulking the rod 13 from both the vertical directions at the same time, the moving distance (stroke) of the die 21, the stripper 22, the die pin 23, the punch 24, and the like can be reduced to half as compared with the method of pressing and caulking from one direction. Accordingly, buckling of the rod 13 that occurs when the rod 13 is caulked can be prevented.

Modification Example 1

Modification Example 1 is a structure in which another member is disposed between the base material 11 and the U-shaped material 12 of the first embodiment (not shown in the drawing).

An intermediate material (fourth member) formed of a material such as copper having a thermal conductivity higher than that of aluminum can be disposed between the base material 11 formed of aluminum and the U-shaped material 12, and the three members can be caulked by the rod 13.

As described above, when a material having a high thermal conductivity is used, the thermal conductivity efficiency of the entire heat sink is improved, and the heat dissipating performance can be improved.

In addition, an intermediate material (fourth member) formed of a metal material such as stainless steel having a higher strength than aluminum can be disposed between the base material 11 and the U-shaped material 12 formed of aluminum, and the three members can be caulked by the rod 13.

As described above, when a material having high strength is used, the strength of the entire heat sink is increased, and a heat sink suitable for a portion where strength is required can be configured.

The intermediate material does not need to be a member having the same shape and the same size as the first base material 31 and/or the U-shaped material 12, and may be a member having a different shape and a different size.

In addition, two or more intermediate materials may be disposed between the base material 11 and the U-shaped material 12.

Second Embodiment

FIG. 7 is a view of a structure 3 of the second embodiment of the present invention, in which (a) is a view before caulking and (b) is a view after caulking.

Configuration of Each Member

The structure 3 of the second embodiment is composed of three metal members, that is, a first base material 31 (first member), a second base material 32 (third member), and a rod 13 (caulked body).

The first base material 31 and the second base material 32 are members having the same shape.

The structure 3 is a heat sink, and the first base material 31 or the second base material 32 is brought into contact with the surface of the member to be cooled to release heat from the first base material 31 and the second base material 32 to the air.

The first base material 31 is a rectangular plate-like member formed of aluminum, and a circular through-hole 313 (first through-hole) into which the rod 13 can be inserted is formed. The other opening portion (first opening portion) of the through-hole 313 is provided on the other surface 312 (one flat surface portion of the first member) of the first base material 31. A circular recessed portion 314 (first recessed portion) that is concentric with the through-hole 313 and has a diameter larger than the diameter of the through-hole 313 is formed around the other opening portion of the through-hole 313. As will be described later, the recessed portion 314 is formed as a recess for housing the head portion 1311 (first head portion) of the lower end portion formed when the rod 13 is caulked, and the radius and the depth are designed so that the head portion 1311 of the lower end portion can be housed without excess or deficiency.

The second base material 32 is a rectangular plate-like member formed of aluminum, and a circular through-hole 323 (third through-hole) into which the rod 13 can be inserted is formed. The other opening portion (third opening portion) of the through-hole 323 is provided on the other surface 322 (one flat surface portion of the third member) of the second base material 32. A circular recessed portion 324 (third recessed portion) that is concentric with the through-hole 323 and has a diameter larger than the diameter of the through-hole 323 is formed around the other opening portion of the through-hole 323. As will be described later, the recessed portion 324 is formed as a recess portion for housing the head portion 1321 (second head portion) of the upper end portion formed when the rod 13 is caulked, and the radius and the depth are designed so that the head portion 1321 of the upper end portion can be housed without excess or deficiency.

The rod 13 is a cylinder formed of aluminum, and is formed to be longer than a length obtained by adding a length of the through-hole 313 and a depth of the recessed portion 314 and a length obtained by adding a length of the through-hole 323 and a depth of the recessed portion 324. In addition, the diameter of the rod 13 is substantially the same as the diameter of the through-hole 313 of the first base material 31 and the diameter of the through-hole 323 of the second base material 32, and the rod 13 can be inserted into the through-hole 313 and the through-hole 323 without a gap.

Structure After Caulking

The one surface 311 of the first base material 31 and the one surface 321 of the second base material 32 are overlapped with each other such that the through-hole 313 of the first base material 31 and the through-hole 323 of the second base material 32 coincide with each other, and the rod 13 is inserted into the through-hole 313 of the first base material 31 and the through-hole 323 of the second base material 32, and the rod 13 is pressed and caulked from above and below by the press machine 2′. The structure 3 obtained in this way is shown in FIG. 7(b).

The lower end portion 131 of the rod 13 is formed into a head portion 1311 that is caulked and stored in the recessed portion 314 of the first base material 31 with substantially no gap.

Similarly, the upper end portion 132 of the rod 13 is formed into a head portion 1321 that is caulked and stored in the recessed portion 324 of the second base material 32 with substantially no gap.

The head portion 1311 and the other surface 312 of the first base material 31 are flush with each other, and the head portion 1321 and the other surface 322 of the second base material 32 are flush with each other.

The head portion 1311 and the recessed portion 314 of the first base material 31, and the head portion 1321 and the recessed portion 324 of the second base material 32 are in contact with each other in a strongly pressure-bonded state by pressing and caulking the rod 13.

In addition, the rod 13 that has been pressed and caulked from above and below is deformed into a substantially barrel shape in which the vicinity of the center in the length direction is bulged. Due to the shape of the truncated barrel shape itself and the firm adhesion between the peripheral surface of the rod 13 and the inner peripheral surface of the through-hole 313 or 323, the rod 13 does not come off in the vertical direction.

Each of the first base material 31 and the second base material 32 is not limited to a rectangular shape, and any shape can be selected depending on the use application.

The first base material 31 and the second base material 32 do not need to be members having the same shape and the same size, and may be members having different shapes and different sizes.

The first base material 31, the second base material 32, and the rod 13 may be formed of a single metal, an alloy, or the like of a metal other than aluminum, for example, copper or iron.

In addition, it is not necessary to form the first base material 31, the second base material 32, and the rod 13 of the same metal, and one of the three may be formed of a metal different from the other two, or all three may be formed of different metals.

In addition, another member may be disposed between the first base material 31 and the second base material 32.

Caulking Device (Fixing Device)

A configuration of a press machine 2′ that is a caulking device for caulking the structure 1 will be described with reference to FIG. 8.

The press machine 2′ has the same configuration as the press machine 2, and includes a die 21′ that abuts the first base material 31 from below, a stripper 22′ that abuts the second base material 32 from above, a die pin 23′ that abuts the rod 13 from below, and a punch 24′ that abuts the rod 13 from above.

However, the shape of the stripper 22′ of the press machine 2′ is different from the shape of the stripper 22 of the press machine 2.

Since the stripper 22′ is in contact with the second base material 32 from above, the contact surface thereof is formed in a planar shape.

Caulking Step (Fixing Method)

FIG. 8 is a view showing a step corresponding to FIG. 2(a) in a caulking step of caulking the base material 11, the U-shaped material 12, and the rod 13.

The caulking step is performed by the press machine 2′. In the press machine 2′, the rod 13 is caulked by moving the die 21′, the stripper 22′, and the punch 24′. Since the caulking step of the second embodiment is substantially the same as the caulking step of the first embodiment, only the different points will be described.

(Step a) An assembly in which one surface 311 of the first base material 31 and one surface 321 of the second base material 32 are superimposed on each other such that the through-hole 313 of the first base material 31 and the through-hole 323 of the second base material 32 coincide with each other is placed on the die 21′. Next, the rod 13 is inserted into the through-hole 313 of the first base material 31 and the through-hole 323 of the second base material 32, and the lower end portion 131 of the rod 13 is placed on the die pin 23′. Thereafter, the stripper 22′ and the punch 24′ move downward, and the stripper 22′ abuts on the second base material 32 as shown in FIG. 8.

(Steps b to e) The steps b to e are the same as the steps b to e of the first embodiment, but the shape of the structure 3 when the caulking of the rod 13 is completed is different from the shape of the structure 1 of the first embodiment.

The lower end portion 131 and the upper end portion 132 of the rod 13 are caulked and stored in the recessed portion 314 of the first base material 31 and the recessed portion 324 of the second base material 32, which are formed as recesses. The head portion 1311 of the lower end portion 131 of the rod 13 that is caulked and the head portion 1321 of the upper end portion 132 that is caulked are flush with the other surface 312 of the first base material 31 and the other surface 322 of the second base material 32, respectively.

As described above, the lower end portion 131 and the upper end portion 132 of the rod 13 are respectively caulked by the die pin 23′ and the punch 24′, and when the caulking is completed, the upper surface of the die 21′ and the lower surface of the stripper 22′ are respectively flush with the upper surface of the die pin 23′ and the lower surface of the punch 24′. Therefore, the head portion 1311 of the lower end portion 131 of the rod 13 that is caulked and the head portion 1321 of the upper end portion 132 of the rod 13 that is caulked are formed to be flush with each other with high accuracy, and the other surface 312 of the first base material 31 and the other surface 322 of the second base material 32 are formed to be flush with each other with high accuracy.

Due to this high accuracy of coplanarity, the other surface 312 of the first base material 31 and the other surface 322 of the second base material 32 can be brought into contact with the surface of another member such as the member to be cooled without a gap. As a result, thermal conduction resistance at the boundary between these two surfaces is reduced, and heat dissipation efficiency as a heat sink is improved.

In addition, since the lower end portion 131 of the rod 13 is caulked and stored in the recessed portion 314 of the first base material 31, the caulked head portion 1311 of the lower end portion 131 is strongly pressure-bonded to the inner surface of the recessed portion 314 of the first base material 31. Similarly, the caulked head portion 1321 of the upper end portion 132 is strongly pressure-bonded to the inner surface of the recessed portion 324 of the second base material 32.

Due to the strong pressure bonding, the first base material 31 and the second base material 32 are firmly anchored to the rod 13, and the thermal conduction resistance at the boundary surface between the first base material 31 and the second base material 32 and the rod 13 is reduced, and the heat dissipation efficiency as a heat sink is increased.

In addition, since the structure 3 can be manufactured only by fixing the first base material 31 and the second base material 32 using the rod 13 having a cylindrical shape, the manufacturing cost can be reduced.

In the second embodiment, as in the first embodiment, the rod 13 is pressed from above by the punch 24′, and at the same time, the lower end portion 131 is pressed by the die pin 23′.

The present invention is not limited thereto, and the lower end portion 131 may be pressed by moving the die pin 23′ upward while the die 21′ and the stripper 22′ are fixed, that is, the rod 13 may be pressed from above by the punch 24′ and at the same time, the lower end portion 131 may be directly pressed by the die pin 23′.

In any method, the rod 13 is pressed and caulked from both the vertical directions at the same time.

With respect to these, the lower end portion 131 and the upper end portion 132 of the rod 13 can be caulked, that is, the rod 13 can be caulked by pressing only in the upward direction by moving only the punch 24′. In addition, the rod 13 can also be pressed and caulked only by moving the die pin 23′. In any method, the rod 13 is pressed and caulked from the up-down direction.

In the method of pressing and caulking the rod 13 from both the vertical directions at the same time, the moving distance (stroke) of the die 21′, the stripper 22′, the die pin 23′, the punch 24′, and the like can be reduced to half as compared with the method of pressing and caulking the rod 13 from one direction. Accordingly, buckling of the rod 13 that occurs when the rod 13 is caulked can be prevented.

Modification Example 2

Modification Example 2 is a structure 4 in which another member is disposed between the first base material 31 and the second base material 32 of the second embodiment.

FIG. 9 is a view of a structure 4 of Modification Example 2, in which (a) shows a view before caulking and (b) shows a view after caulking.

An intermediate material 33 (fourth member) formed of a material such as copper having a thermal conductivity higher than that of aluminum can also be disposed between the first base material 31 and the second base material 32 formed of aluminum, and the three members can be caulked by the rod 13.

As described above, when a material having a high thermal conductivity is used, the thermal conductivity efficiency of the entire heat sink is improved, and the heat dissipating performance can be improved.

In addition, an intermediate material (fourth member) formed of a metal material such as stainless steel having higher strength than aluminum is disposed between the first base material 31 and the second base material 32 formed of aluminum, and the three members can be caulked by the rod 13.

As described above, when a material having high strength is used, the strength of the entire heat sink is increased, and a heat sink suitable for a portion where strength is required can be configured.

The intermediate material 33 does not need to be a member having the same shape and the same size as the first base material 31 and/or the second base material 32, and may be a member having a different shape and a different size.

In addition, two or more intermediate materials may be disposed between the first base material 31 and the second base material 32.

The structure 1 in which the base material 11 as one plate-like member and the U-shaped material 12 are fixed was described as the first embodiment, and the structure 3 in which the first base material 31 and the second base material 32 as two plate-like members are fixed was described as the second embodiment. However, the present invention is not limited to the first embodiment and the second embodiment.

The members to be fixed may have any shapes. In addition, as in Modification Examples 1 and 2, the members to be fixed are not limited to two members, and may be three or more members.

In addition, the structure 1, the structure 3, and the structure 4, the press machine 2 and the press machine 2′, and the method of fixing using these, of the first embodiment and the modification example 1 and the second embodiment and the modification example 2 according to the present invention have been described in detail with reference to the drawings, but the specific configuration is not limited to these embodiments and the modification examples thereof, and the present invention includes a design change or the like without departing from the scope of the present invention.

In addition, the respective embodiments and modification examples described above can be combined with each other by using the technology of each other as long as there is no particular contradiction or problem in the purpose, the configuration, and the like.

REFERENCE SYMBOLS LIST

• • 1: structure
  • 11: base material
  • 111: base portion
  • 1111: one surface of base portion 111
  • 1112: other surface of base portion 111
  • 112: protrusion portion
  • 113: through-hole
  • 114: recessed portion
  • 12: U-shaped material
  • 121: base portion
  • 122: bending portion
  • 123: fitting hole
  • 13: rod
  • 131: lower end portion
  • 1311: head portion in which lower end portion 131 is caulked
  • 132: upper end portion
  • 1321: head portion in which upper end portion 132 is caulked
  • 2,2′: press machine
  • 21, 21′: die
  • 211: die suspension bolt
  • 212: coil spring
  • 213: insertion hole
  • 22, 22′: stripper
  • 221: stripper suspension bolt
  • 222: coil spring
  • 223: insertion hole
  • 224: protruding portion
  • 23, 23′: die pin
  • 231: die pin backing
  • 232: die damper
  • 24, 24′: punch
  • 241: punch backing
  • 242: stripper damper
  • 3: structure
  • 31: first base material
  • 311: one surface of first base material 31
  • 312: other surface of first base material 31
  • 313: through-hole
  • 314: recessed portion
  • 32: second base material
  • 321: one surface of second base material 32
  • 322: other surface of second base material 32
  • 323: through-hole
  • 324: recessed portion
  • 33: intermediate material
  • 4: structure