JP2005264798A - Compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the rise of the temperature of an intake refrigerant gas to increase compression efficiency by applying a treatment to a valve plate without installing a new member and changing a structure. <P>SOLUTION: A rear housing 14 having an intake chamber 24 and a discharge chamber 25 is joined to the end face of a cylinder block 11 through a valve/port formed body 13. The valve/port formed body 13 comprises a valve plate 26, an intake valve plate 27, and a discharge valve plate 28. An intake port 29 and a discharge port 30 are formed in the valve plate 26. The valve plate 26 is formed of a cold-rolled steel sheet and to which a carburization is applied. Carburized layers 26a are formed on both surfaces of the valve plate 26. Both carburized layers 26a are formed so that the total thickness thereof is 50% or higher of the thickness of a raw material. The carburization is applied so that iron carbide is not deposited in the carburized layers 26a. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a compressor provided with a steel valve plate.

  In a piston type compressor, a piston is housed in a cylinder bore formed in a cylinder block, and a housing that partitions and forms a suction chamber and a discharge chamber is connected to the cylinder block via a valve plate in which a suction hole and a discharge hole are formed. It is joined to the end face of Then, the rotation of the rotating shaft is converted into the reciprocating motion of the piston through the drive mechanism, and the reciprocating motion of the piston sucks the refrigerant gas in the suction chamber through the suction hole into the compression chamber in the cylinder bore, and discharges the compressed refrigerant gas. It is comprised so that it may discharge to a discharge chamber through a hole.

  The discharge chamber provided in the housing is heated to a high temperature by the compressed refrigerant gas (discharge gas). Therefore, the low-temperature refrigerant gas flowing into the suction chamber from the external refrigerant circuit is heated by the heat transmitted through the wall surface of the housing and the valve plate that partition the discharge chamber and the suction chamber. Then, before the refrigerant gas in the suction chamber is sucked into the compression chamber in the cylinder bore, the refrigerant gas is heated and expands, so that the amount of refrigerant gas substantially sucked into the compression chamber is reduced and the volume efficiency is lowered. There is a problem of doing. In addition, when the intake refrigerant gas is heated, the temperature of the compressed gas compressed in the compression chamber also rises. For this reason, the temperature of the discharged refrigerant gas rises, and heat from the compressor, the seal member of the cooling circuit, etc. There has been a problem that deterioration due to is likely to occur.

  As means for solving this problem, a piston type compressor in which heat insulating means is provided on the partition walls of the suction chamber and the discharge chamber has been proposed (see, for example, Patent Document 1). As shown in FIG. 8, in the compressor disclosed in Patent Document 1, a housing 53 including a suction chamber 51 and a discharge chamber 52 has a suction hole 55 and a discharge hole 56 formed on the end surface of the cylinder block 54. Are joined via a valve plate 57. The suction chamber 51 and the discharge chamber 52 are partitioned by a partition wall 58, and the partition wall 58 is provided with a heat insulating groove 58a as heat insulating means.

Further, in a compressor provided with a cylinder head in which a suction chamber (suction chamber) and a discharge chamber are formed at the end of the cylinder, the cylinder head is manufactured from a material with good heat dissipation, and the suction of the cylinder head is performed. A chamber formed of a heat insulating material has also been proposed (see, for example, Patent Document 2).
JP-A-5-164042 (paragraphs [0006] and [0012] in FIG. 1, FIG. 1) Japanese Utility Model Publication No. 2-331382

  However, in the compressor of Patent Document 1, since the heat insulating groove 58a is provided in the partition wall 58, the structure of the housing 53 is different from the conventional structure, and the existing housing cannot be used. In the compressor of Patent Document 2, the suction chamber is formed of a heat insulating material, so that the structure around the suction chamber needs to be changed correspondingly, and the existing housing or the like cannot be used as it is.

  The present invention has been made in view of the above-described problems, and the object thereof is to provide a process for the valve plate without providing a new member or changing the structure, thereby allowing the intake refrigerant gas to be reduced. An object of the present invention is to provide a compressor capable of suppressing the temperature rise and improving the compression efficiency.

  In order to achieve the above-mentioned object, the invention according to claim 1 is a compressor provided with a steel valve plate, wherein the thickness of the carburized layer is 50% of the thickness of the material with respect to the valve plate. Carburizing treatment is performed so that it becomes the above. For example, when a cold-rolled steel plate is used as the valve plate, the thermal conductivity is as high as 80 W / (mK), but the thickness of the carburized layer is 50% or more of the material thickness with respect to the valve plate. By performing the carburizing process, the thermal conductivity becomes 60 W / (mK) or less. As a result, the heat of the refrigerant gas in the discharge chamber is suppressed from being transmitted to the refrigerant gas in the suction chamber via the valve plate. That is, by subjecting the valve plate to carburization, it is possible to suppress the temperature rise of the intake refrigerant gas and improve the compression efficiency. In addition, the carburizing process increases the hardness of the valve plate, and the required strength can be ensured even if the valve plate is thinner than the valve plate that is not carburized. Moreover, an inexpensive iron material can be used as a material for the valve plate. That is, in the present invention, carburizing treatment, which is a surface treatment technique that has been conventionally used to increase the hardness of a steel sheet, is adopted as a means for reducing the thermal conductivity of a valve plate, which has not been considered so far. Thus, the object can be achieved by using an inexpensive iron material.

  According to a second aspect of the present invention, in the first aspect of the invention, the carburizing treatment is performed in a state where no iron carbide layer is deposited on the carburized layer. In the present invention, as the carburizing process, since no iron carbide layer is deposited in the carburized layer, the thermal expansion coefficient of the valve plate is maintained in substantially the same manner as when the carburizing process is not performed. Therefore, the assembling property when assembling the compressor does not change.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the carburizing process is a vacuum carburizing process. In the present invention, a carburized layer having a necessary thickness (depth) can be formed in a shorter time than when carburizing is performed by other carburizing processes such as solid carburizing, liquid carburizing, and gas carburizing.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the material of the valve plate is a cold-rolled steel sheet. Cold-rolled steel sheets are inexpensive and have good workability, so they are suitable as a material for valve plates and can reduce the manufacturing cost of valve plates.

  The invention according to claim 5 is the invention according to any one of claims 1 to 3, wherein the material of the valve plate is a hot rolled mild steel sheet. In the present invention, the workability is somewhat inferior to that of the cold-rolled steel sheet, but the same effects as those of the invention of claim 4 are achieved.

  The invention according to claim 6 is the invention according to any one of claims 1 to 3, wherein the material of the valve plate is an electromagnetic soft iron plate. In this invention, although the price is somewhat higher than that of the cold-rolled steel sheet, the same effect as that of the invention of claim 4 is achieved.

  According to a seventh aspect of the present invention, in the invention according to any one of the first to sixth aspects, the compressor includes a piston housed in a cylinder bore formed in a cylinder block, and the piston reciprocates. Therefore, the refrigerant compressor is configured to perform suction, compression, and discharge of the refrigerant gas. In this invention, in a piston type compressor, there exists an effect similar to the invention as described in any one of Claims 1-6.

  The invention according to claim 8 is the invention according to claim 7, wherein the valve plate is disposed between a housing forming a suction chamber and a discharge chamber and the cylinder block, and carburized layers are formed on both surfaces thereof. Is formed. In this invention, compared with the case where the carburized layer having the same thickness as the total thickness of the carburized layers formed on both sides of the cylinder block is formed only on one side of the valve plate, the temperature rise of the intake refrigerant gas is suppressed. The

  According to the present invention, by performing processing on the valve plate without providing a new member or changing the structure, it is possible to suppress the temperature rise of the intake refrigerant gas and improve the compression efficiency. .

Hereinafter, an embodiment in which the present invention is embodied in a piston-type variable capacity compressor used in a refrigeration circuit of a vehicle air conditioner will be described with reference to FIGS.
FIG. 1 is a longitudinal sectional view of the variable capacity compressor (hereinafter simply referred to as a compressor). In FIG. 1, the left side is the front of the compressor and the right side is the rear of the compressor. As shown in FIG. 1, the housing of the compressor 10 includes a cylinder block 11, a front housing 12 joined and fixed to the front end of the cylinder block 11, and a valve / port forming body 13 at the rear end of the cylinder block 11. And a rear housing 14 joined and fixed.

  A crank chamber 15 is defined between the cylinder block 11 and the front housing 12 in the housing. A drive shaft 16 is rotatably supported between the cylinder block 11 and the front housing 12 so as to pass through the crank chamber 15. The drive shaft 16 is operatively connected to an engine (not shown) that is a travel drive source of the vehicle. The drive shaft 16 is supplied with power from the engine and is rotated in the direction of arrow R.

  A lug plate 17 having a substantially disk shape is fixed to the drive shaft 16 in the crank chamber 15 so as to be integrally rotatable. A swash plate 18 as a cam plate is accommodated in the crank chamber 15. The drive shaft 16 is inserted through an insertion hole 18 a formed in the center of the swash plate 18. A hinge mechanism 19 is interposed between the lug plate 17 and the swash plate 18. The swash plate 18 can be rotated synchronously with the lug plate 17 and the drive shaft 16 by the hinge connection with the lug plate 17 via the hinge mechanism 19 and the support of the drive shaft 16 via the insertion hole 18a. The drive shaft 16 can be tilted with respect to the drive shaft 16 while being slid in the axis T direction.

  In the cylinder block 11, a plurality of cylinder bores 20 (only one is shown in FIG. 1) are formed around the axis T of the drive shaft 16 so as to penetrate in the front-rear direction (left-right direction in the drawing) at equal angular intervals. The single-headed piston 21 is accommodated in each cylinder bore 20 so as to be movable in the front-rear direction. The front and rear openings of the cylinder bore 20 are closed by a valve / port forming body 13 and a piston 21, and a compression chamber 22 whose volume changes in accordance with the movement of the piston 21 in the front and rear direction is defined in the cylinder bore 20. .

  The piston 21 is anchored to the outer peripheral portion of the swash plate 18 via a pair of shoes 23. A suction chamber 24 and a discharge chamber 25 are defined between the valve / port forming body 13 and the rear housing 14 in the housing.

  The valve / port forming body 13 includes a valve plate 26, a suction valve plate 27 provided on the cylinder block 11 side of the valve plate 26, and a discharge valve plate 28 provided on the rear housing 14 side of the valve plate 26. Has been. As shown in FIGS. 1 and 3, the valve plate 26 is formed with a suction port 29 on the radially outer side and a discharge port 30 on the radially inner side at a position facing each cylinder bore 20. A suction valve 31 is formed on the suction valve plate 27 at a position corresponding to the suction port 29, and a discharge valve 32 is formed on the discharge valve plate 28 at a position corresponding to the discharge port 30. The opening position of the discharge valve 32 is regulated by a retainer 33 fixed to the valve plate 26.

  In the housing of the compressor 10, an extraction passage 34, an air supply passage 35, and a control valve 36 are provided. The extraction passage 34 connects the crank chamber 15 and the suction chamber 24. The air supply passage 35 connects the discharge chamber 25 and the crank chamber 15. In the middle of the air supply passage 35, a known control valve 36 made of an electromagnetic valve is disposed.

  Next, the valve plate 26 will be described. The valve plate 26 is made of steel (in this embodiment, made of a cold rolled steel plate) and is subjected to carburizing treatment. As the cold-rolled steel plate, SPCC, SPCD, and SPCE are used, and SPCD is particularly preferable. As shown in FIG. 2, the carburized layer 26 a is formed on both surfaces of the valve plate 26. For convenience of illustration, the illustration of the carburized layer 26a is omitted in FIG. Both carburized layers 26a are formed such that the total thickness is 50% or more of the thickness of the material. That is, the carburizing process is performed on the valve plate 26 so that the thickness of the carburized layer 26a is 50% or more of the thickness of the material. In this embodiment, the carburization process is performed in a state where no iron carbide layer is deposited in the carburized layer 26a, that is, in a state where carbon atoms enter the crystal structure of steel. The carburizing process is performed by a vacuum carburizing process.

  The thickness of the valve plate 26 is, for example, 2 to 3 mm, and the thickness of the carburized layer 26 a is formed to be 60% (1.2 to 1.8 mm) of the thickness of the material, for example. When the thickness of the carburized layer 26a is larger, the effect of suppressing the rise in the temperature of the intake refrigerant gas is larger, and when the carburized layer 26a is formed over the entire thickness of the material, the effect of suppressing the increase in the temperature of the intake refrigerant gas is increased. Is preferable. However, the thicker the carburized layer 26a is, the longer the time required for the carburizing process is. Therefore, the thickness of the carburized layer 26a is set by combining the two.

The vacuum carburizing treatment can be performed by a known vacuum carburizing method. For example, after the inside of the furnace is evacuated, a carburizing gas such as methane gas (CH ₄ ) or propane gas (C ₃ H ₈ ) having a reduced pressure is introduced. The carburizing process is performed on the valve plate 26 in which the processing of the suction port 29, the discharge port 30, and the like has been completed.

  FIG. 4 shows the relationship between the carburization ratio and the thermal conductivity and the relationship between the carburization ratio and the thermal expansion coefficient when the carburization process is performed in a state where no iron carbide layer is deposited on the carburized layer 26a. In FIG. 4, the rhombus indicates the relationship between the carburization ratio and the thermal conductivity, and the square indicates the relationship between the carburization ratio and the thermal expansion coefficient. The carburization ratio is a percentage of the carburized layer thickness to the material thickness. Carburization ratio = (carburized layer thickness / material thickness) × 100 (%).

  From FIG. 4, it was confirmed that the thermal expansion coefficient was maintained substantially constant (± 2%) even when the carburization ratio changed from 0% (no carburizing treatment) to 100%. It was also confirmed that the thermal conductivity decreased as the carburization ratio increased, and that the carburization ratio was 50% or more and the thermal conductivity was 60 W / (mK) or less.

Next, the effect | action is demonstrated about the compressor comprised as mentioned above.
The swash plate 18 rotates integrally with the rotation of the drive shaft 16, and the rotational motion of the swash plate 18 is converted into the reciprocating motion of each piston 21 through the shoe 23. Is reciprocated. By continuing this drive, the suction of the refrigerant gas from the suction chamber 24 to the compression chamber 22, the compression of the suction refrigerant gas, and the discharge of the compressed refrigerant gas to the discharge chamber 25 are sequentially repeated. The refrigerant (carbon dioxide is used in this embodiment) in the suction chamber 24 moves through the suction port 29 and the suction valve 31 by moving from the top dead center position to the bottom dead center position of each piston 21. Through the compression chamber 22. The refrigerant gas sucked into the compression chamber 22 is compressed to a predetermined pressure by the movement from the bottom dead center position to the top dead center position side of the piston 21, and enters the discharge chamber 25 via the discharge port 30 and the discharge valve 32. And discharged. The refrigerant discharged into the discharge chamber 25 is sent out to an external refrigerant circuit from a discharge hole (not shown).

  By adjusting the opening of the control valve 36, the amount of high-pressure discharge gas introduced into the crank chamber 15 via the air supply passage 35 and the amount of gas discharged from the crank chamber 15 via the extraction passage 34 are obtained. The balance is controlled and the internal pressure of the crank chamber 15 is determined. The difference between the internal pressure of the crank chamber 15 and the internal pressure of the compression chamber 22 via the piston 21 is changed according to the change of the internal pressure of the crank chamber 15, and the inclination angle of the swash plate 18 (perpendicular to the axis T of the drive shaft 16). As a result, the stroke of the piston 21, that is, the discharge capacity of the compressor 10 is adjusted.

  For example, when the internal pressure of the crank chamber 15 is reduced, the inclination angle of the swash plate 18 is increased, the stroke of the piston 21 is increased, and the discharge capacity of the compressor 10 is increased. Conversely, when the internal pressure of the crank chamber 15 increases, the inclination angle of the swash plate 18 decreases, the stroke of the piston 21 decreases, and the discharge capacity of the compressor 10 decreases.

  During the operation of the compressor 10, the compressed refrigerant gas becomes high pressure and high temperature and is temporarily stored in the discharge chamber 25. When the valve plate 26 is formed of a cold rolled steel plate that has not been carburized, the heat conductivity of the refrigerant gas in the discharge chamber 25 is approximately 80 W / (mK) because the heat conductivity of the valve plate 26 is approximately 80 W / (mK). It is easy to transmit via the valve plate 26. As a result, the suction refrigerant gas in the suction chamber 24 is heated or heated when the suction refrigerant gas passes through the suction port 29, so that the substantial amount of refrigerant gas sucked into the compression chamber 22 is reduced. , Volumetric efficiency is reduced.

  However, in this embodiment, since the carburizing process is performed on the valve plate 26 so that the thickness of the carburized layer 26a is 50% or more of the thickness of the material, the thermal conductivity is 60 W / (mK). ) It becomes the following. As a result, the heat of the refrigerant gas in the discharge chamber 25 is suppressed from being transmitted to the refrigerant gas in the suction chamber 24 via the valve plate 26. In addition, the intake refrigerant gas is suppressed from being heated when passing through the intake port 29. As a result, the substantial amount of refrigerant gas sucked into the compression chamber 22 is increased, the volumetric efficiency is improved, and the compression efficiency is also improved.

This embodiment has the following effects.
(1) Carburizing treatment is performed on the valve plate 26 of the compressor 10 so that the thickness of the carburized layer 26a is 50% or more of the thickness of the material. Therefore, even if an inexpensive iron material is used as the material of the valve plate 26, the thermal conductivity can be reduced to 60 W / (mK) or less, and the heat of the refrigerant gas in the discharge chamber 25 is sucked through the valve plate 26. Transmission to the refrigerant gas in the chamber 24 can be suppressed, and a rise in temperature of the intake refrigerant gas can be suppressed to improve compression efficiency. Further, the carburizing process increases the hardness of the valve plate 26, and the required strength can be ensured even if the valve plate 26 is thinner than the valve plate that is not carburized.

  (2) The carburizing treatment is performed in a state where no iron carbide layer is deposited on the carburized layer 26a. As a result, the coefficient of thermal expansion of the valve plate 26 is maintained almost the same as when the carburizing process is not performed, and when the compressor 10 is assembled, the valve plate 26 is assembled in the same way as when the valve plate 26 that has not been carburized is used. Attaching work can be performed.

  (3) A vacuum carburizing process is performed as the carburizing process. Therefore, the carburized layer 26a having a required thickness (depth) can be formed in a shorter time than when carburizing is performed by other carburizing processes such as solid carburizing, liquid carburizing, and gas carburizing. Further, the carburizing process in a state where no iron carbide layer is deposited on the carburized layer 26a can be easily performed as compared with other carburizing processes.

  (4) As a material of the valve plate 26, a cold rolled steel plate is used. Cold-rolled steel sheet is suitable for the material of the valve plate 26 because it is cheap and has good workability, and the manufacturing cost of the valve plate 26 can be reduced.

  (5) The compressor 10 has a piston type in which a piston 21 is housed in a cylinder bore 20 formed in the cylinder block 11, and refrigerant gas is sucked and compressed / discharged by the reciprocating motion of the piston 21. It is a compressor. Therefore, the suction chamber 24 and the discharge chamber 25 are closer to each other than other compressors, and the heat in the discharge chamber 25 is easily transmitted to the suction refrigerant gas in the suction chamber 24 via the valve plate 26. However, a rise in the temperature of the intake refrigerant gas can be suppressed by a relatively simple process called carburizing process.

  (6) The valve plate 26 is disposed between the cylinder block 11 and the rear housing 14 forming the suction chamber 24 and the discharge chamber 25, and carburized layers 26a are formed on both surfaces thereof. Therefore, when the thickness of the carburized layer 26a is the same, the temperature rise of the intake refrigerant gas is suppressed as compared with the case where the carburized layer 26a is formed only on one side of the valve plate 26. This is because the suction valve plate 27 exists on the side of the valve plate 26 corresponding to the cylinder bore 20, but there is a region in the valve plate 26 that directly contacts the refrigerant gas in the compression chamber 22 around the suction valve 31. . As a result, since the high-temperature compressed gas compressed to the discharge pressure in the compression stroke comes into contact with the valve plate 26, heat is transmitted from that portion to the periphery of the suction port 29, and heat is transmitted to the suction refrigerant gas. Is done. However, if the carburized layer 26a is formed on both sides of the valve plate 26, heat transfer to the intake refrigerant gas through the above-described path is suppressed.

  (7) Carbon dioxide is used as a refrigerant for the vehicle air conditioner. When carbon dioxide refrigerant is used, for example, the refrigerant capacity per unit volume is large as compared with the case where chlorofluorocarbon refrigerant is used, and the capacity of the cylinder bore 20 is reduced in a compressor having the same capacity. Therefore, when the refrigerant gas in the suction chamber 24 is heated and expands, and the substantial amount of refrigerant gas sucked into the compression chamber 22 decreases, the rate of decrease in volumetric efficiency increases. Therefore, in the compressor 10 that handles the carbon dioxide refrigerant, the effect of improving the volumetric efficiency by suppressing the expansion due to the heating of the intake refrigerant gas is increased. Therefore, it can be said that it is particularly effective when applied to the compressor 10 that compresses the carbon dioxide refrigerant.

The embodiment is not limited to the above, and may be configured as follows, for example.
The valve plate 26 may be carburized so that the thickness of the carburized layer 26a is 50% or more of the thickness of the material. For example, as shown in FIG. 5, the carburized layer 26a is formed only on the rear housing 14 side, or the carburized layer 26a is formed only on the cylinder block 11 side as shown in FIG. Alternatively, a configuration in which the carburized layer 26a is formed over the entire thickness of the valve plate 26 may be employed. In the case where the carburized layer 26a is formed only on one side of the valve plate 26, it is preferable that the carburized layer 26a be formed on the rear housing 14 side. This is because the area facing the discharge gas is larger on the rear housing 14 side.

As shown in FIG. 7, the suction chamber 24 and the discharge chamber 25 may be arranged such that the suction chamber 24 is disposed on the inner side and the discharge chamber 25 is disposed on the outer side.
The carburizing process is not limited to the configuration in which the carburized layer 26a has no precipitation of the iron carbide layer, and the carburized layer 26a may have been subjected to the precipitation of the iron carbide layer.

The carburizing process is not limited to the vacuum carburizing process, and may be performed by other carburizing processes such as solid carburizing, liquid carburizing, and gas carburizing.
○ The carburizing gas in the vacuum carburizing treatment is not limited to saturated chain hydrocarbons such as methane gas and propane gas, but may be unsaturated chain hydrocarbons such as ethylene and acetylene.

  The material of the valve plate 26 is not limited to a cold-rolled steel plate, but may be a steel material that can be carburized. However, in consideration of the workability as the valve plate 26 and the ease of carburizing treatment, in addition to the cold-rolled steel plate, a hot-rolled mild steel plate and an electromagnetic soft iron plate can be mentioned.

  Not only the variable capacity swash plate compressor, but also a double-headed or fixed capacity swash plate compressor. The swash plate may be applied to a swash plate compressor of a type (wobble type) that does not rotate integrally with the drive shaft but swings as the drive shaft rotates.

  The housing of the compressor 10 is not limited to a configuration in which the cylinder block 11 is sandwiched between the front housing 12 and the rear housing 14. For example, the housing may be constituted by a front housing and a rear housing, a crank chamber may be provided in one of the front housing and the rear housing, and a cylinder having a cylinder bore may be fitted in the other housing.

O It may apply to piston type compressors other than a swash plate type, and may apply not only to a piston type compressor but to a scroll type compressor.
(Circle) not only the compressor which uses a carbon dioxide as a refrigerant | coolant of a vehicle air conditioner but you may apply to the compressor using a CFC-type refrigerant | coolant, for example.

The drive shaft 16 is not limited to a configuration that is rotated by receiving power from the engine, and may be configured to be driven by a motor.
(Circle) not only the compressor used for a vehicle air conditioner but you may apply to the electric compressor used for a home air conditioner, for example.

O You may apply not only to the compressor used for an air conditioner but to the compressor used for refrigeration cycles other than an air conditioner, for example, the refrigerating cycle of a refrigerator or a freezer.
The following technical idea (invention) can be understood from the embodiment.

(1) In the inventions according to claims 1 to 7, a carburized layer is formed over the entire thickness of the valve plate.
(2) In the invention according to any one of claims 1 to 8 and the technical idea (1), carbon dioxide is used as a refrigerant.

  (3) A compressor having a steel valve plate, wherein the valve plate is carburized so that the thickness of the carburized layer is 1 mm or more.

The longitudinal cross-sectional view which shows one Embodiment actualized in the piston type variable displacement compressor. The model enlarged view of the valve and port formation part of FIG. AA sectional view taken on the line AA of FIG. The graph which shows the relationship between a carburizing ratio, thermal conductivity, and a thermal expansion coefficient. The model enlarged view of the valve and port formation part of another embodiment. The model enlarged view of the valve and port formation part of another embodiment. The fragmentary sectional view of another embodiment. The fragmentary sectional view of a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Compressor, 11 ... Cylinder block, 14 ... Rear housing as housing which forms suction chamber and discharge chamber, 20 ... Cylinder bore, 21 ... Piston, 24 ... Suction chamber, 25 ... Discharge chamber, 26 ... Valve plate, 26a ... carburized layer.

Claims (8)

  A compressor including a steel valve plate, wherein the carburizing process is performed on the valve plate so that a thickness of a carburized layer is 50% or more of a thickness of a material. Compressor.   2. The compressor according to claim 1, wherein the carburizing treatment is performed in a state where no iron carbide layer is deposited on the carburized layer.   The compressor according to claim 1 or 2, wherein the carburizing process is a vacuum carburizing process.   The compressor according to any one of claims 1 to 3, wherein a material of the valve plate is a cold-rolled steel plate.   The compressor according to any one of claims 1 to 3, wherein a material of the valve plate is a hot rolled mild steel plate.   The compressor according to any one of claims 1 to 3, wherein a material of the valve plate is an electromagnetic soft iron plate.   The piston compressor is a piston type compressor configured such that a piston is accommodated in a cylinder bore formed in a cylinder block, and refrigerant gas is sucked in, compressed and discharged by reciprocation of the piston. The compressor according to any one of claims 6 to 7.   The compressor according to claim 7, wherein the valve plate is disposed between a housing forming a suction chamber and a discharge chamber and the cylinder block, and a carburized layer is formed on both surfaces thereof.

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