JP2002180959A - Compressor for thermo-compression type refrigerating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compressor for a thermo-compression type refrigerating machine capable of reducing the weight while holding necessary abrasion resistance and mechanical strength. SOLUTION: A cylinder block 11 comprises a first part 41 regulating a region, at least, receiving a high pressure among the inside face of a cylinder bore 16 and a residual second part 42. The first part is made of a material having a higher abrasion resistance and mechanical strength than those of the second part, for example, a steel based material and has a thick wall part 43 thicker than the other part in the high pressure side end. The second part is made of a material lighter than the first material, for example, an aluminum based material. a piston 17 is inserted into the cylinder bore and reciprocated by a drive mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a compressor for a vapor compression refrigerator.

[0002]

2. Description of the Related Art Refrigeration cycles or refrigerators are used in various fields such as air conditioners for vehicles. Usually, R134 is used as the refrigerant in the refrigerator. This type of refrigerant does not need to be compressed to high pressure.

Recently, in order to prevent global warming, it has been proposed to use CO ₂ as a refrigerant for a refrigerator of a vehicle air conditioner. A compressor of a refrigerator using CO ₂ is called a compressor for a vapor compression refrigerator. In this type of refrigerator, CO ₂ is compressed to a high pressure by the steam compression type refrigerator compressor during operation. That is, a high operating pressure is required for a compressor for a vapor compression refrigerator. Therefore, a large compression reaction force is applied to the compressor during operation.

Conventionally, a reciprocating compressor including a cylinder block having a cylinder bore, a piston inserted into the cylinder bore, and a drive mechanism for reciprocating the piston in the cylinder bore has been known. In the reciprocating compressor, the cylinder block is generally made entirely of an aluminum-based material for weight reduction.

[0005]

As described above, a compressor for a vapor compression refrigerator is required to have a high operating pressure. In particular, a very high compression reaction force acts on the high pressure side end corresponding to the top dead center of the piston. For this reason, when the cylinder block is made of an aluminum-based material, problems arise in wear resistance, mechanical strength, and the like. On the other hand, if the entire cylinder block is made of an iron-based material having high wear resistance and mechanical strength, the weight of the product becomes extremely large.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a compressor for a vapor compression refrigerator having necessary abrasion resistance and mechanical strength and capable of being reduced in weight.

[0007]

According to the present invention, there is provided a vapor compression type having a cylinder block having a cylinder bore, a piston inserted into the cylinder bore, and a drive mechanism for reciprocating the piston in the cylinder bore. In the compressor for a refrigerator, the cylinder block includes a first portion that defines at least a region that receives a high pressure on an inner surface of the cylinder bore, and a remaining second portion, and the first portion is the second portion. The second part is lighter than the first part, and is made of a material having higher wear resistance and mechanical strength than the first part and has a thicker part at the high pressure side end than the other part. A compressor for a vapor compression refrigerator, characterized by being made of the above material.

[0008] The first portion may be made of an iron-based material, and the second portion may be made of an aluminum-based material.

[0009] The thick portion may gradually increase as approaching the high pressure side end face.

[0010] The thick portion may have a substantially uniform thickness.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a compressor for a vapor compression refrigerator according to a first embodiment of the present invention will be described.

The compressor for a vapor compression refrigerator shown in FIG. 1 is of a so-called fixed capacity swash plate type compressor, and includes a cylinder block 11 and a front housing 12 in contact with the front end of the cylinder block 11. , A cylinder head 14 disposed at the rear end of the cylinder block 11 via a valve plate 13. Cylinder block 11, front housing 12, valve plate 1
3, and the cylinder head 14 are fastened and fixed in the axial direction by fastening means such as bolts 15.

The cylinder block 11 has a plurality of cylinder bores 16 (only one of which is shown) around a central axis. Each cylinder bore 16 extends in the axial direction, and a piston 17 is inserted therein so as to be slidable in the axial direction.

The valve plate 13 has a suction port 18 and a discharge port 19 corresponding to each cylinder bore 16. A suction port 18 is provided between the valve plate 13 and the cylinder block 11.
Is provided with a suction valve 21 opposed to. A discharge valve 22 facing the discharge port 19 is provided between the valve plate 13 and the cylinder head 14. A retainer 23 facing the discharge valve 22 is fixed to the valve plate 13. The valve plate 13, the suction valve 21, the discharge valve 22, and the retainer 23
It is pre-assembled as a valve plate assembly.

The suction chamber 2 is provided around the cylinder head 14.
4 and a discharge chamber 25 is formed in the center. The suction port 18 communicates with a suction chamber 24. The discharge port 19 communicates with the discharge chamber 25. Although not shown, a suction port and a discharge port are connected to the suction chamber 24 and the discharge chamber 25, respectively.

A main shaft 31 extending on a central axis is supported by the cylinder block 11 and the front housing 12 so as to be rotatable and not to move in the axial direction. Spindle 3
A swash plate 32 inclined at a predetermined angle is fixed to 1. A shoe 3 is provided on both sides in the axial direction of the peripheral portion of the swash plate 32.
The piston 17 is axially engaged via 3 and 34. The shoes 33 and 34 are held by the piston 17 and are slidable with respect to the swash plate 32. Main shaft 31, swash plate 3
2, and the shoes 33 and 34 together form a drive mechanism.

When the main shaft 31 is driven to rotate, the swash plate 32 also rotates together with the main shaft 31. In accordance with the rotation of the swash plate 32, the piston 17 is driven via the shoes 33 and 34 and reciprocates in the cylinder bore 16. According to the reciprocating motion of the piston 17, CO ₂ is converted into a refrigerant gas in the suction chamber 24.
It is sucked into the cylinder bore 16 through the suction port 18, compressed and discharged to the discharge chamber 25 through the discharge port 19. When the piston 17 moves near the top dead center, the refrigerant gas is compressed in the cylinder bore 16 to a considerably high pressure. That is, the inner surface of the cylinder bore 16 has a region receiving high pressure corresponding to the vicinity of the top dead center of the piston 17.

In consideration of this point, the cylinder block 11
Is divided into a first portion 41 that defines at least a region of the inner surface of the cylinder bore 16 that receives a high pressure, and a remaining second portion 42 formed of a base material. It is made of a material having high mechanical strength, for example, an iron-based material. On the other hand, the second portion 42 is made of a lighter material than the first portion 41, for example, an aluminum-based material.

Further, it is assumed that the first portion 41 has a thick portion 43 at the high pressure side end portion which is thicker than the other portions. The thick portion 43 has a shape that gradually increases toward the outside as it approaches the end face on the high pressure side.

The cylinder block 11 includes a second portion 4
2 is formed by press-fitting the first portion 41 from the end face on the high pressure side. The press-fitting of the first part 41
2 are locked by locking projections or inward flanges 44 formed on the base 2. After press-fitting, additional processing is performed as necessary.

According to the above structure, the cylinder block 1
1 is made of a relatively lightweight aluminum-based material, and the high pressure area on the inner surface of the cylinder bore 16 is made of an iron-based material having high wear resistance and mechanical strength. It is possible to provide a compressor for a vapor compression refrigerator that has abrasion resistance and mechanical strength and can be reduced in weight.

With reference to FIG. 2, a description will be given of a vapor compression refrigerator compressor according to a second embodiment of the present invention. 1 are given the same reference numerals, and description thereof is omitted.

The compressor for a vapor compression refrigerator shown in FIG. 2 is also of a so-called fixed-capacity swash plate type compressor, and the first portion 41 of the cylinder block 11 is made of iron having high wear resistance and high mechanical strength. The second part 42 is made of an aluminum-based material that is lighter than the first part 41.

In the first portion 41, the thick portion 43 has a substantially uniform thickness. Therefore, the first portion 41 has a stepped portion 4 at the boundary between the thin portion 45 and the thick portion 43.
6.

The press-fitting allowance for the thick portion 43 is set relatively large. Therefore, the thick portion 43 is tightly fitted to the second portion 42. On the other hand, the press-fitting margin of the thin portion 44 is set relatively small. Therefore, the thin portion 45 is loosely fitted to the second portion 42. Thus, the first and second
The portions 41 and 42 are prevented from loosening due to the difference in thermal expansion and the strength is thereby reduced. After the first portion 41 is press-fitted into the second portion 42 and locked by the locking projection or the inward flange 44, additional processing is performed as necessary.

The same operation and effect as those of the compressor for the vapor compression type refrigerator shown in FIG. 1 can be obtained by the compressor for the vapor compression type refrigerator shown in FIG.

In the above description, the fixed displacement type swash plate type compressor has been described as an example. However, it is needless to say that the present invention can be similarly applied to a so-called variable displacement type swash plate type compressor and other various reciprocating compressors. No.

[0028]

As described above, according to the present invention,
It is possible to provide a compressor for a vapor compression refrigerator having necessary wear resistance and mechanical strength and capable of being reduced in weight.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a compressor for a vapor compression refrigerator according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a vapor compression refrigerator compressor according to a second embodiment of the present invention.

DESCRIPTION OF SYMBOLS 11 Cylinder block 12 Front housing 13 Valve plate 14 Cylinder head 15 Bolt 16 Cylinder bore 17 Piston 18 Inlet 19 Outlet 21 Inlet valve 22 Discharge valve 23 Retainer 24 Suction chamber 25 Discharge chamber 31 Main shaft 32 Swash plate 33, 34 shoe 41 first portion 42 second portion 43 thick portion 44 locking projection or inward flange 45 thin portion 46 stepped portion

Claims (4)

[Claims] 1. A vapor compression refrigerator compressor comprising: a cylinder block having a cylinder bore; a piston inserted into the cylinder bore; and a drive mechanism for reciprocating the piston in the cylinder bore. A first portion defining at least a region of the inner surface of the cylinder bore that receives a high pressure;
A second portion, wherein the first portion is made of a material having higher wear resistance and mechanical strength than the second portion, and has a thicker wall at the high pressure side end than the other portion. And a second portion made of a lighter material than the first portion. 2. The first part is made of an iron-based material,
The compressor according to claim 1, wherein the second portion is made of an aluminum-based material. 3. The compressor according to claim 1, wherein the thick portion gradually increases as approaching the high-pressure end surface. 4. The compressor according to claim 1, wherein the thick portion has a substantially uniform thickness.