JPH07103140A - Compressor - Google Patents

Abstract

PURPOSE:To improve the durability of a compressor in optimizing a sliding material for the compressor using a specific coolant by forming the base material of a piston pin with hardened steel, and simultaneously applying nickel composite platings, having a specific composition, onto the surface. CONSTITUTION:When a shaft 2 pressed in a rotor 3 is rotated by a motor consisting of this rotor 3 and a stator 4, a piston 7 reciprocates in the inner part of a cylinder 6 via a connecting rod 5 consisting of an aluminum alloy and a piston pin 10. In consequence, compressed gas consisting of coolants 1 and bitetrafluoroethane is condensed in the inner part of a space 9 to be formed by the piston 7 and the cylinder 6. In a compressor like this, a base material 10a of the piston pin 10 is made up of hardened steel. In succession, a nickel composite plating layer 10b made up of mixing fine grains 10c of poly tetrafluoroehtylene 10 to 35 volume% in a matrix alloy made of nickel as the main ingredient are installed on a surface of the base material 10a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor used in a refrigerating machine, an air conditioner or the like.

[0002]

2. Description of the Related Art In recent years, refrigerating machines and air conditioners have been used conventionally due to environmental problems such as destruction of the ozone layer.
FC-12), difluorochloromethane (hereinafter referred to as HCFC-22), etc., a refrigerant 1, 1, 1, 2 tetrafluoroethane (hereinafter referred to as HF) containing no chlorine in the molecule.
A change to C-134a) is under consideration. However, the refrigerant that does not contain chlorine in the molecule has poor lubrication performance and needs to improve the characteristics of the sliding material of the compressor.

An example of a conventional compressor will be described below with reference to the drawings. 1 is a compressor. Reference numeral 2 is a shaft, 3 is a rotor, 4 is a stator, and the rotor 3 and the stator 4 form a pair to form a motor. 5 is a connecting rod,
6 is a cylinder, 7 is a piston, and 8 is a piston pin. The shaft 2 press-fitted into the rotor 3 rotates by the motor formed by the rotor 3 and the stator 4. At this time, the connecting rod 5 attached to the eccentric part of the shaft 2
The rotational movement of the shaft 2 is transmitted through the piston pin 8 attached to the other end of the connecting rod 5 and fixed to the piston 7, and the piston 7 reciprocates in the cylinder 6. The refrigerant gas CFC-12 is sucked into the space 9 formed by the piston 7 and the cylinder 6,
Compressed.

Here, in order to reduce the energy loss of reciprocating motion, the connecting rod 5 is made of an aluminum alloy which is a lightweight member, and the contact area between the connecting rod 5 and the piston pin 8 which has a small bearing area and is in a severe sliding condition is durable. In order to improve the property, the piston pin 8 is made of hardened steel.

[0005]

However, the above-mentioned structure is considered on the assumption that the conventional refrigerants CFC-12 and HCFC-22 having high lubricating performance are dissolved in the lubricating oil of the compressor. There is. When the refrigerant HFC-134a, which does not contain chlorine in the molecule and is inferior in lubrication performance, is used, especially at the contact portion between the connecting rod and the piston pin, the aluminum alloy that is the material of the connecting rod is adhered to the surface of the connecting pin, and as a result, the connecting rod is formed. Wear increases and sufficient durability cannot be obtained. Therefore, it is necessary to newly optimize the sliding material for the refrigerant that does not contain chlorine. Therefore, in order to reduce the energy loss of reciprocating motion, the connecting rod 5 is made of aluminum die cast (JI
Since it is formed by S: ADC12), it is necessary to select a material in which aluminum does not easily adhere to the surface of the piston pin 10.

In view of the above problems, the present invention is directed to the refrigerant HFC-1.
The sliding material is optimized with respect to the compressor using 34a to improve the durability of the compressor.

[0007]

In order to solve the above-mentioned problems, a compressor of the present invention uses a refrigerant HFC-13 as a compressed gas.
4a, the connecting rod is made of an aluminum alloy, and a nickel-phosphorus composite plating is formed on the surface of the piston pin, in which a matrix alloy containing nickel as a main component is mixed with polytetrafluoroethylene.

In order to solve the above problems, the compressor of the present invention has a structure in which the compressed gas is the refrigerant HFC-134a and the connecting rod is made of an aluminum alloy, and the surface of the piston pin is subjected to oxynitriding treatment and nitriding treatment. A layer and an iron oxide film formed on it.

[0009]

The present invention has the above-described structure to prevent the adhesive wear of the contact portion between the connecting rod and the piston pin, thereby improving the durability of the compressor.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of the compressor of the present invention. 1
Is a compressor. Reference numeral 2 is a shaft, 3 is a rotor, 4 is a stator, and the rotor 3 and the stator 4 form a pair to form a motor. Further, 5 is a connecting rod, 6 is a cylinder, 7 is a piston, and 10 is a piston pin. The shaft 2 press-fitted into the rotor 3 rotates by the motor formed by the rotor 3 and the stator 4. At this time, the rotational movement of the shaft 2 is transmitted through the piston pin 10 attached to the eccentric portion of the shaft 2 and fixed to the piston 7, and the piston 7 reciprocates in the cylinder 6. Then, in the space 9 formed by the piston 7 and the cylinder 6,
The refrigerant HFC-134a is sucked and compressed. here,
FIG. 2 shows a sectional view of the piston pin 10 of this embodiment. The base material 10a of the piston pin 10 is made of chromium molybdenum steel (J
After processing as IS: SCM415), fine particles 10C of polytetrafluoroethylene having an average particle size of about 1 μm and excellent in lubricity.
Nickel-based alloy plating bath in which
Aging treatment was performed at ℃. The nickel-phosphorus composite plating layer 10b has a phosphorus content of 8 to 10% by weight. The nickel-phosphorus composite plating layer 10b has a hardness of HV 400 to 600, a thickness of about 10 μm, and contains 20 to 25% by volume of polytetrafluoroethylene.

In order to verify the effect of the above constitution in a short time, a wear tester was used to evaluate the amount of wear and the state of the sliding surface. This wear tester is one in which a fixed piece slides on an outer peripheral surface of a rotating piece that rotates at a constant speed with a constant load. In addition,
The material of the connecting rod was used for the fixed piece, and the material of the piston pin was used for the rotating piece. The sliding conditions were set to a speed of 0.5 m / s, a load of 100 N, and a surface pressure of 200 N / cm ² , which were more severe than the sliding conditions of the actual connecting rod and piston pin of the compressor. The test was dry friction without oil supply. It was carried out under the conditions. Further, the refrigerant HFC-134a was used as the atmosphere gas. Here, the refrigerant gas was continuously supplied at atmospheric pressure with the test piece installation part of the friction tester being semi-sealed. The results are shown in (Table 1).

[0013]

[Table 1]

In Comparative Example 1, the conventional refrigerant C is used as the atmosphere gas.
Using FC-12, the fixed piece is aluminum die cast (JIS: JIS) which is the material of the connecting rod used in the conventional compressor.
ADC12) is used, and the rotary piece is made of chromium molybdenum steel (J) which is the material of the piston pin used in the conventional compressor.
This is the case when IS: SCM415) is used. Comparative Example 1
As shown in the result, the sliding condition is speed 0.5m / s, load 5
When it is 0N, the wear of the connecting rod is 1-2.
It is suppressed to μm and reproduces the actual wear amount of the connecting rod in the compressor. Also, the sliding condition is a speed of 0.5 m /
At s and a load of 100 N, it can be seen that transfer of the aluminum alloy was observed on the sliding surface of the rotating piece and significant adhesive wear occurred. This is because the sliding condition is speed 0.5m /
It is considered that, when the load is 100 N and the load is 100 N, sufficient durability cannot be ensured by the lubricating performance of the chlorine adsorption layer of CFC-12.

Comparative Example 2 uses HFC-13 as the atmosphere gas.
4a and aluminum die cast (JIS: ADC) which is the material of the connecting rod used in the conventional compressor for the fixed piece.
12) is used, and the rotary piece is made of chrome molybdenum steel (JIS: the material of the piston pin used in the conventional compressor).
This is the case when SCM415) is used. As shown in the results of Comparative Example 2, when the sliding conditions were a speed of 0.5 m / s and a load of 50 N, transfer of the aluminum alloy was observed on the sliding surface of the rotating piece.
It can be seen that adhesive wear has occurred. This clearly shows the difference between the refrigerants HFC-134a and CFC-12 which do not contain chlorine in the molecule. However, in the case where the sliding conditions were a speed of 0.5 m / s and a load of 100 N, Comparative Example 2
The result was that the amount of wear of the fixed piece was smaller than that of the fixed piece of Comparative Example 1. It is considered that this is because when the adhesion occurs, the sliding state becomes unstable and the variation in the wear amount of the fixed piece increases.

In Comparative Example 3, for the purpose of forming a dissimilar metal material having excellent wear resistance, the rotary piece was made of chrome molybdenum steel (JIS: SCM415), and after processing 50
Nitriding treatment is performed at 0 to 600 ° C., and titanium nitride is vapor-deposited on the surface by an ion coating method to form a film having a hardness HV1800 to 2300 having a film thickness of 1 to 3 μm. As shown in the results of Comparative Example 3,
Significant adhesive wear has occurred. Therefore, even if the surface of the piston pin is coated with titanium nitride ions, the amount of wear of the fixed piece and the condition of the sliding surface cannot be improved.
Therefore, it is shown that cohesive wear cannot be reduced only by dissimilar metal materials, especially surface hardening. On the other hand, in order to obtain the same specifications as in the present embodiment, the fixed piece is made of aluminum die cast (JIS: ADC1)
2) was used, and the rotating piece was made of chromium molybdenum steel (JIS: SCM415), which is the material of the piston pin, and the surface of which was plated with nickel-phosphorus composite. Even when the refrigerant HFC-134a is used as the atmosphere gas and the sliding conditions are a speed of 0.5 m / s and a load of 100 N, the conventional refrigerant C is used.
Adhesive wear as shown in the results of Comparative Example 1 using FC-12 does not occur. Further, the wear amount can be suppressed to about 1/10 of the wear amount of the fixed piece of Comparative Example 1, and the transfer of the aluminum alloy is not confirmed on the sliding surface of the rotating piece. It is considered that the sliding state at the contact portion of is greatly improved and sufficient durability can be secured. This is because the polytetrafluoroethylene particles dispersed on the surface of the piston pin have self-lubricity,
It is considered that the polytetrafluoroethylene particles spread over the entire contact surface with sliding, so that the friction coefficient becomes small and adhesion wear at the contact surface between the fixed piece and the rotating piece is prevented. Therefore, it is considered that the self-lubricating property enables the normal wear to be maintained even under the HFC-134a having the inferior lubrication performance, and exhibits the excellent durability.

In conclusion, the actual connecting rod 5 of the compressor
Aluminum die cast (JIS: ADC12) is used for the piston pin 10 and chromium molybdenum steel (JIS: SC
It is considered that it is possible to prevent cohesive wear and improve the durability of the compressor by using M415) on the surface of which nickel-phosphorus composite plating is formed.

As described above, in this embodiment, the compressed gas is HFC-134a, and the connecting rod is formed by aluminum die casting (JIS: ADC12).
By forming a nickel phosphorus composite plating layer containing 20 to 25% by volume of polytetrafluoroethylene particles on the base material of IS: SCM415), wear of connecting rod and piston pin can be reduced, and conventional refrigerant CFC-12 or more. It was found that the durability of can be maintained.

According to this embodiment, a nickel phosphorus composite plating layer having 20 to 25% by volume of polytetrafluoroethylene particles dispersed therein was formed on the surface of the rotary piece. Similar effects can be obtained by dispersing 10 to 35% by volume. When the content of polytetrafluoroethylene particles is less than 10% by volume, sufficient self-lubricating property cannot be obtained and wear resistance is deteriorated. On the other hand, when the polytetrafluoroethylene content is more than 35% by volume, the uniformity and surface roughness of the plating layer deteriorate.

A second embodiment of the present invention will be described below with reference to the drawings. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 3 shows a sectional view of a compressor which is a second embodiment of the present invention. Here, FIG. 4 shows a sectional view of the piston pin 11 of the present embodiment. The piston pin 11 is the base material 11a
After being processed into chromium molybdenum steel (JIS: SCM415), a nitriding layer 11b having a thickness of about 30 μm and an iron oxide film 11c having a thickness of 1 to 2 μm thereon are formed by a salt bath nitriding method at a treatment temperature of 500 to 600 ° C. And an oxynitriding layer is formed. The surface condition is porous.

In order to verify the effect of the above structure in a short time, a wear tester was used to evaluate the amount of wear and the state of the sliding surface. This wear tester is one in which a fixed piece slides on an outer peripheral surface of a rotating piece that rotates at a constant speed with a constant load. In addition,
The material of the connecting rod was used for the fixed piece, and the material of the piston pin was used for the rotating piece. The sliding conditions were set to a speed of 0.5 m / s, a load of 100 N, and a surface pressure of 200 N / cm ² , which were more severe than the actual sliding conditions of the connecting rod and piston pin of the compressor. The test was dry friction without oil supply. It was carried out under the conditions. Further, the refrigerant HFC-134a was used as the atmosphere gas. Here, the refrigerant gas was continuously supplied at atmospheric pressure with the test piece installation part of the friction tester being semi-sealed. The results are shown in (Table 2).

[0023]

[Table 2]

In Comparative Example 1, the conventional refrigerant C is used as the atmosphere gas.
Using FC-12, the fixed piece is aluminum die cast (JIS: JIS) which is the material of the connecting rod used in the conventional compressor.
ADC12) is used, and the rotary piece is made of chromium molybdenum steel (J) which is the material of the piston pin used in the conventional compressor.
This is the case when IS: SCM415) is used. Comparative Example 1
As shown in the result, the sliding condition is speed 0.5m / s, load 5
When it is 0N, the wear of the connecting rod is 1-2.
It is suppressed to μm and reproduces the actual wear amount of the connecting rod in the compressor. Also, the sliding condition is a speed of 0.5 m /
At s and a load of 100 N, it can be seen that transfer of the aluminum alloy was observed on the sliding surface of the rotating piece and significant adhesive wear occurred. This is because the sliding condition is speed 0.5m /
It is considered that, when the load is 100 N and the load is 100 N, sufficient durability cannot be ensured by the lubricating performance of the chlorine adsorption layer of CFC-12.

Comparative Example 2 uses HFC-13 as the atmosphere gas.
4a and aluminum die cast (JIS: ADC) which is the material of the connecting rod used in the conventional compressor for the fixed piece.
12) is used, and the rotary piece is made of chrome molybdenum steel (JIS: the material of the piston pin used in the conventional compressor).
This is the case when SCM415) is used. As shown in the results of Comparative Example 2, when the sliding conditions were a speed of 0.5 m / s and a load of 50 N, transfer of the aluminum alloy was observed on the sliding surface of the rotating piece.
It can be seen that adhesive wear has occurred. This clearly shows the difference between the refrigerants HFC-134a and CFC-12 which do not contain chlorine in the molecule. However, in the case where the sliding conditions were a speed of 0.5 m / s and a load of 100 N, Comparative Example 2
The result was that the amount of wear of the fixed piece was smaller than that of Comparative Example 1. It is considered that this is because when the adhesion occurs, the sliding state becomes unstable and the variation in the wear amount of the fixed piece increases.

In Comparative Example 3, the rotary piece was formed by using chromium molybdenum steel (JIS: SCM415) as a base material, and then forming a nitriding layer by a salt bath nitriding method. As shown in the results of Comparative Example 3, significant adhesive wear occurs. Therefore, even if the nitriding layer is formed on the surface of the piston pin, the amount of wear of the fixed piece and the state of the sliding surface cannot be improved. Therefore, it is shown that adhesion wear cannot be reduced only by the nitriding layer.

On the other hand, in order to obtain the same specifications as in the present embodiment, aluminum die cast (JIS: ADC12), which is the material for the connecting rod, is used for the fixed piece, and chromium molybdenum steel (the material for the piston pin, which is the material for the piston pin, is used for the rotating piece. JIS: SCM
415) whose surface is subjected to oxynitriding treatment, the conventional refrigerant CFC-12 is used when the refrigerant HFC-134a is used as the atmospheric gas and the sliding condition is a speed of 0.5 m / s and a load of 100N. Sliding condition is speed 0.5m / s,
It is considered that the wear amount can be suppressed to 1/10 or less than that when the load is 100 N, and sufficient durability can be secured because no adhesion is confirmed on the sliding surface. It is considered that this is because the sliding characteristics of the iron oxide film layer formed on the surface of the piston pin prevent the adhesion wear at the contact surface between the piston pin and the connecting rod because the friction coefficient becomes small. Therefore, it is considered that the self-lubricating property enables the normal wear to be maintained even under the HFC-134a having the inferior lubrication performance, and exhibits the excellent durability.

In conclusion, the actual compressor connecting rod 5
Aluminum die cast (JIS: ADC12) is used for the piston pin 11 and chromium molybdenum steel (JIS: SC
It is considered that it is possible to prevent cohesive wear and improve the durability of the compressor by using M415) that has been subjected to an oxynitriding treatment on its surface to form an iron oxide film.

As described above, in this embodiment, the compressed gas is HFC-134a, the connecting rod is formed by aluminum die casting (JIS: ADC12), and the piston pin is made of chromium molybdenum steel (J
IS: SCM 415) base material with a salt bath treatment method resulting in a film thickness of 3
By forming a nitriding layer of about 0 μm and an iron oxide film of 1 to 2 μm on it, adhesion wear on the contact surface between the connecting rod and the piston pin can be reduced, and the durability of the conventional refrigerant CFC-12 or higher can be maintained. I knew I could do it.

The surface of the iron oxide film is porous,
If even a small amount of oil is supplied, there is an advantage that the oil penetrates into the iron oxide surface and the oil film is easily formed on the sliding surface.

[0031]

As described above, according to the present invention, by forming a nickel phosphorus composite plating layer containing 20 to 25% by volume of polytetrafluoroethylene particles on the surface of the piston pin, the refrigerant HFC- Even under severe conditions using 134a, the sliding state of the contact portion between the connecting rod and the piston pin can be improved, and as a result, the durability of the compressor can be improved.

As described above, according to the present invention, by forming the nitriding layer on the surface of the piston pin and the iron oxide film on the nitriding layer, the contact portion between the connecting rod and the piston can be contacted even under severe conditions using the refrigerant HFC-134a. It is possible to improve the sliding condition, and as a result, it is possible to improve the durability of the compressor.

[Brief description of drawings]

FIG. 1 is a sectional view of a compressor using a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a piston pin according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a compressor using a second embodiment of the present invention.

FIG. 4 is an enlarged sectional view of a piston pin according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a conventional compressor.

FIG. 6 is an enlarged sectional view of a conventional piston pin.

[Explanation of symbols]

 2 ... Shaft 5 ... Connecting rod 10 ... Piston pin

Claims (2)

[Claims] 1. A shaft for connecting compressed gas to refrigerants 1, 1, 1, 2 tetrafluoroethane and an electric motor, and a connecting rod made of aluminum alloy and having a bearing portion at one end thereof attached to the shaft. A piston pin attached to a bearing portion at the other end of the connecting rod,
In a component of a compressor including a piston fixed to the piston pin and a cylinder that forms a compression chamber integrally with the piston, a base material of the piston pin is a hardened steel, and nickel is a main component. A compressor characterized in that a nickel phosphorus composite plating in which 10 to 35% by volume of polytetrafluoroethylene is mixed with the matrix alloy is coated on the surface thereof. 2. A shaft to be connected to an electric motor, wherein the gas to be compressed is refrigerant 1, 1, 1, 2 tetrafluoroethane, and a connecting rod formed of an aluminum alloy and having a bearing portion at one end thereof attached to the shaft. A piston pin attached to a bearing portion at the other end of the connecting rod,
In a component of a compressor including a piston fixed to the piston pin and a cylinder that forms a compression chamber integrally with the piston, a base material of the piston pin is a quenching steel, and an oxynitriding treatment is performed on a surface thereof. And a nitriding layer and an iron oxide film formed on the nitriding layer.