ROTARY COMPRESSOR

Description

FIELD OF INVENTION

The present invention relates to a rotary compressor.

BACKGROUND OF THE INVENTION

It is known that a rotary compressor includes a cylinder, an eccentric portion of a shaft that turns inside the cylinder, a piston rotatably fitted to the eccentric portion and forming a compression chamber between itself and the cylinder, and a vane dividing the compression chamber into a high pressure space and a low pressure space, as disclosed in Japanese Unexamined Patent Application Publication No. 2012-13015A hereinafter called PTL1.

In PTL1, to prevent the tip of the vane from separating from the piston and to increase the volume of the compression chamber, the vane is provided with a cylindrical portion formed at the end on the cylinder side, the cylinder is provided with a holding portion that rotatably supports the root portion of the vane, and the piston is provided with a vane groove into which the vane is reciprocally inserted.

As such, when the eccentric portion revolves, the vane swings with the root portion as a fulcrum, and the vane reciprocates within the vane groove of the piston.

However, there is a possibility that the vane life is shortened due to the frictional wear since the vane swings while sliding on the holding portion of the cylinder with the root portion as a fulcrum.

Therefore, the development of the compressor, that can increase the volume of the compression chamber as well as that can prevent shortening of vane life, is required.

CITATION LIST

Patent Literature

• • PTL 1: Japanese Unexamined Patent Application Publication No. 2012-13015A

SUMMARY OF THE INVENTION

It is an objective of the present inventions to provide a compressor that can increase the volume of the compression chamber as well as that can prevent shortening of vane life.

In order to achieve the above objective, an embodiment of the present invention provides a rotary compressor comprising: a compression mechanism including: a cylinder; an eccentric portion of a shaft that turns inside the cylinder; a piston rotatably fitted to the eccentric portion and forming a compression chamber between itself and the cylinder; and a vane including a swing rod and a root portion formed into a cylindrical shape at the end of the swing rod, and extending in the axial direction of the shaft, wherein the vane extends across the cylinder and the piston, and divides the compression chamber into a high pressure space and a low pressure space, wherein the cylinder includes a holding portion on its inner surface that rotatably supports the root portion, and the piston is formed with a vane groove into which the swing rod is reciprocally inserted, and wherein the cylinder includes a clearance portion between a recess portion of the holding portion of the inner surface and the root portion of the vane.

Firstly, according to the embodiment of the present invention, the vane includes the swing rod and the root portion that extends in the axial direction of the shaft at an end on a cylinder side, and the vane extends across the cylinder and piston. Moreover, the cylinder is formed with the holding portion that rotatably supports the root portion, and the piston is formed with the vane groove into which the vane is reciprocally inserted.

As such, when the eccentric portion revolves, the vane swings with the root portion as a fulcrum, and the vane reciprocates within the vane groove of the piston.

Since the vane groove is formed in the piston, the thickness of the cylinder of the compression mechanism of the rotary compressor can be reduced. Therefore, even if the rotary compressor has a cylinder of the same size as a conventional rotary compressor, the inner diameter of the cylinder can be increased. As a result, it is possible to increase the volume of the compression chamber.

Secondly, since the clearance portion is formed between the recess portion of the holding portion of the cylinder and the root portion of the vane, the root portion is not in contact with the recess portion of the cylinder. The area where the root portion of the vane and the holding portion of the cylinder slide can be reduced.

As such, even if the vane swings while sliding on the holding portion of the cylinder with the root portion as a fulcrum, the frictional wear of the vane can be reduced.

Therefore, according to the embodiment of the rotary compressor of the present invention, it is possible to increase the volume of the compression chamber as well as to prevent shortening of vane life.

BRIEF DESCRIPTION OF DRAWINGS

The principle of the present invention and its advantages will become apparent in the following description taking in consideration with the accompanying drawings in which:

FIG. 1 is a is an explanation view illustrating a schematic configuration of a rotary compressor 100 including a compression mechanism 3 according to an embodiment of the present invention;

FIG. 2 is a cross sectional view taken along line II-II of FIG. 1;

FIG. 3 is an enlarged view of a root portion 39b of a vane 39 of FIG. 2;

FIG. 4 is a perspective view of the vane 39 of FIG. 2,

FIG. 5A is an explanation view of an oil supply passage in the compression mechanism 3; and

FIG. 5B is the explanation view of a clearance portion 34 between the vane 39 and a curved portion 31b of the cylinder 31 of a first compression section 30A of FIG. 5A.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic longitudinal sectional view of a rotary compressor 100 according to an embodiment. Although a twin-cylinder rotary compressor including two cylinders is illustrated in FIG. 1, the rotary compressor of the embodiment is not limited to the twin-cylinder rotary compressor. A single-cylinder rotary compressor or a multiple-cylinder rotary compressor including three or more cylinders may also be used.

A rotary compressor 100 includes, in a sealed container 1, an electric motor 2 and a compression mechanism 3 to be driven by the electric motor 2 through intermediation of a shaft 4. Suction pipes 5 and a discharge pipe 6 are connected to the sealed container 1. The suction pipes 5 are connected to the sealed container 1 from outside so as to pass through the sealed container 1. The discharge pipe 6 is configured to discharge a compressed gas refrigerant.

A bottom portion of the sealed container 1 serves as an oil reservoir la configured to store a lubricating oil. The lubricating oil stored in the oil reservoir la moves upward through an oil feed passage 4b formed in a center portion of the shaft 4 in an axial direction of the shaft 4 due to a differential pressure acting in the oil feed passage 4b, and then the lubricating oil is fed to the compression mechanism 3.

The electric motor 2 includes a rotator 2a mounted to the shaft 4 and a stator 2b configured to rotationally drive the rotator 2a. By starting energization of the stator 2b, the rotator 2a is rotated to transmit rotational power to the compression mechanism 3 through intermediation of the shaft 4.

The compression mechanism 3 includes a first compression section 30A provided in an upper portion, a second compression section 30B provided in a lower portion, a first support member 40 arranged on an upper end surface of the first compression section 30A, and a second support member 50 arranged on a lower end surface of the second compression section 30B. An intermediate partition plate 60 is arranged between the first compression section 30A and the second compression section 30B so as to define the first compression section 30A and the second compression section 30B.

The first support member 40 includes a bearing portion 41 having a hollow cylindrical shape, which is configured to support the shaft 4 so as to be freely rotatable, and an end plate portion 42 having a flat annular shape, which is configured to close an upper opening of a through hole 36 inside of the later-described cylinder 31 of the first compression section 30A. The second support member 50 similarly includes a bearing portion 51 having a hollow cylindrical shape, which is configured to support the shaft 4 so as to be freely rotatable, and an end plate portion 52 having a flat annular shape, which is configured to close a lower opening of the through hole 36 inside the later-described cylinder 31 of the second compression section 30B.

An intermediate partition plate 60 is arranged between the first compression section 30A and the second compression section 30B so as to define the first compression section 30A and the second compression section 30B. In this manner, the compression mechanism 3 is constructed of the second support member 50, the second compression section 30B, the intermediate partition plate 60, the first compression section 30A, and the first support member 40 laminated in the stated order from a lower side to an upper side.

Now, the first compression section 30A and the second compression section 30B are described. The first compression section 30A and the second compression section 30B basically have similar configurations, and thus the first compression section 30A is representatively described below.

The first compression section 30A includes the cylinder 31 having a cylindrical shape, a vane 39 which includes a swing rod 39a and a root portion 39b formed into a cylindrical shape at the end of the swing rod 39a and which extends in the axial direction of the shaft 4, and a piston 32 formed with a vane groove 32a into which the swing rod 39a is reciprocally inserted. The cylinder 31 has the through hole 36 through which the shaft 4 passes. As shown in FIG. 2 and FIG. 3, the cylinder 31 includes a holding portion 31a on its inner surface 31c that rotatably supports the root portion 39b.

Moreover, the holding portion 31a of the cylinder 31 is formed with a recess portion 31b that is formed in a curved shape that curves in the direction from the root portion 39b of the vane 39 toward the holding portion 31a. The shape of the recess portion 31b is not limited to a curved shape that curves in the direction from the root portion 39b of the vane 39 toward the holding portion 31a, as long as it is concave in same the direction, may be a triangular concave shape or a wavy concave shape.

Furthermore, a clearance portion 34 is formed between the recess portion 31b of the inner surface 31c of the cylinder 31 and the root portion 39b of the vane 39 and is formed so as to extend in the axial direction of the root portion 39b.

The piston 32 is rotatably fitted to an outer periphery of an eccentric portion 4a of the shaft 4 and is configured to rotate eccentrically inside the through hole 36. As shown in FIG. 2, the piston 32 is formed with the vane groove 32a into which the swing rod 39a of the vane 39 is reciprocally inserted.

The vane 39 is configured to extend across the cylinder 31 and the piston 32. The vane 39 includes the swing rod 39a which is a member swingably formed in a plate shape and the root portion 39b formed into a cylindrical shape at the end of the swing rod 39a and which extends in the axial direction of the shaft 4. As such, when the eccentric portion 4a of the shaft 4 revolves, the vane 39 swings with the root portion 39b as a fulcrum, and the vane 39 reciprocates within the vane groove 32a of the piston 32.

Moreover, since the vane groove 32a is formed in the piston 32, the thickness of the cylinder 31 of the compression mechanism 3 of the rotary compressor 100 can be reduced. Therefore, even if the rotary compressor 100 has a cylinder 31 of the same size as a conventional rotary compressor, the inner diameter of the cylinder 31 can be increased.

Therefore, it is possible to increase the volume of a compression chamber 33 which is formed between the inner surface 31c of the through hole 36 formed in the cylinder 31 and an outer peripheral surface of the piston 32. The compression chamber 33 is divided by the vane 39 into a high pressure space and a low pressure space.

As shown in FIG. 3, the root portion 39b of the vane 39 includes a flat portion 39c formed as a flat plane and extending in the axial direction of the root portion 39b facing the clearance portion 34.

In general, a sliding area that slides on the holding portion 31a needs to be polished with high precision. On the other hand, the other area does not require the same precision as the sliding area. As such, since the root portion 39b of the vane 39 includes a flat portion 39c, the processing time of the vane 39 can be shortened.

Moreover, to polish the vane 39, it is necessary to secure the vane 39 to the processing tool in two opposing planes. Since the flat portion 39c can be used as a flat surface for fixing, not only can the polishing accuracy be improved, but the polishing work will be easier.

In the first compression section 30A and the second compression section 30B, the suction and the compression of the gas refrigerant are repeated by the rotation of the shaft 4. Then, the refrigerant gas compressed in each of the first compression section 30A and the second compression section 30B to be discharged into the internal space of the sealed container 1 is discharged out of the sealed container 1 from the discharge pipe 6, thereby circulating the refrigerant in a refrigerant circuit.

As shown in FIG. 5A, an oil supply passage 70 is formed as a gap between the first compression section 30A and the second compression section 30B, i.e. between the two cylinders 31. Moreover, the oil supply passage 70 is connected to the clearance portion 34.

As mentioned above, the internal space of the sealed container 1 is filled with the compressed gas refrigerant containing lubricating oil. As such, lubricating oil is guided to the oil supply passage 70 between the first compression section 30A and the second compression section 30B and then to lubricating oil is guided to the clearance portion 34. An arrow “A” in FIG. 5A indicates the flow of lubricating oil from outside the cylinder 31 to the clearance portion 34.

Therefore, the oil supply passage 70 is formed between the first compression section 30A and the second compression section 30B to guide lubricating oil to the clearance portion 34. Since the oil supply passage 70 is connected to the clearance portion 34, the clearance portion 34 can function as a passage for guiding lubricating oil between the holding portion 31a and the vane 39.

Next, the flow of lubricating oil from the oil reservoir la to the vane 39 is described in detail with reference to FIG. 1 to FIG. 5B.

Firstly, when power is supplied to the electric motor 2, the shaft 4 is rotated by the electric motor 2. The rotation is forward. By the rotation of the shaft 4, the eccentric portion 4a performs an eccentric rotating motion inside the through hole 36. Along with the eccentric rotating motion of the eccentric portion 4a, the piston 32 performs an eccentric rotating motion inside the through hole 36 located inside cylinder 31. Along with the rotation of the piston 32, low-pressure refrigerant is sucked into compression mechanism 3 and is compressed in the compression chamber 33 to turn into high-pressure refrigerant. After passing through discharge ports (not shown) of the first compression section 30A and the second compression section 30B, the high-pressure refrigerant is discharged into an internal space of the sealed container 1.

Secondly, during an operation of the rotary compressor 100, lubricating oil stored in the oil reservoir la of the sealed container 1 is fed to the compression mechanism 3 through the oil feed passage 4b so as to lubricate the compression mechanism 3.

Moreover, lubricating oil entrains with the compressed gas refrigerant. As such, lubricating oil entrained in the compressed gas refrigerant is guided to the oil supply passage 70 so that the compressed gas refrigerant is guided around the vane 39 in the compression mechanism 3 via the clearance portion 34.

As a result, lubricating oil is supplied to the compression mechanism 3 via the oil feed passage 4b as well as via the oil supply passage 70 and the clearance portion 34.

According to the embodiment, the vane 39 includes the swing rod 39a and the root portion 39b as well as extends across the cylinder 31 and piston 32. Moreover, the cylinder 31 is formed with the holding portion 31 a that rotatably supports the root portion 39b, and the piston 32 is formed with the vane groove 32a into which the vane 39 is reciprocally inserted. As such, when the eccentric portion 4a revolves, the vane 39 swings with the root portion 39b as a fulcrum, and the vane 39 reciprocates within the vane groove 32a of the piston 32.

Moreover, since the vane groove 32a is formed in the piston 32, the thickness of the cylinder of the compression mechanism 3 of the rotary compressor 100 can be reduced. As such, the inner diameter of the cylinder 31 can be increased, even if the rotary compressor 100 has a cylinder 31 of the same size as a conventional rotary compressor. Therefore, it is possible to increase the volume of the compression chamber 33.

Moreover, since the clearance portion 34 is formed between the recess portion 31b of the cylinder 31 and the root portion 39b of the vane 39, the root portion 39b is not in contact with the recess portion 31b of the cylinder 31. The area where the root portion 39b of the vane 39 and the holding portion 31a of the cylinder 31 slide can be reduced. As such, even if the vane 39 swings while sliding on the holding portion 31a of the cylinder 31 with the root portion 39b as a fulcrum, the frictional wear of the vane 39 can be reduced. The clearance portion 34 formed between the recess portion 31b of the cylinder 31 and the root portion 39b of the vane 39, as well as the oil supply passage 70 can be used to supply lubricating oil around the vane 39.

Therefore, according to the embodiment of the rotary compressor 100, it is possible to increase the volume of the compression chamber 33 as well as to prevent shortening of vane life.

Although specific embodiments of the invention have been disclosed and described as well as illustrated in the companying drawings, it is simply for the purpose of better understanding of the principle of the present invention and it is not as a limitation of the scope and spirit of the teaching of the present invention. Adaption and modification to various structures such as design or material of the invention are possible and apparent to a skilled person without departing from the scope of the present invention which is to be determined by the claims.

LIST OF REFERENCES

• • 100: rotary compressor
  • 1: sealed container
  • 1a: oil reservoir
  • 2: electric motor
  • 2a: rotator
  • 2b: stator
  • 3: compression mechanism
  • 4: shaft
  • 4a: eccentric portion
  • 4b: oil feed passage
  • 5: suction pipe
  • 6: discharge pipe
  • 30A: first compression section
  • 30B: second compression section
  • 31: cylinder
  • 31a: holding portion
  • 31b: recess portion
  • 31c: inner surface
  • 32: piston
  • 32a: vane groove
  • 33: compression chamber
  • 34: clearance portion
  • 36: through hole
  • 39: vane
  • 39a: swing rod
  • 39b: root portion
  • 39c: flat portion
  • 40: first support member
  • 41: bearing portion
  • 42: end plate portion
  • 50: second support member
  • 51: bearing portion
  • 52: end plate portion
  • 60: intermediate partition plate
  • 70: oil supply passage
  • A: flow of lubricating oil from outside the cylinder 31 to the clearance portion 34