JPH04143479A - Manufacture of roller piston rotary compressor - Google Patents

Abstract

PURPOSE:To enhance the corrosion resistance of a roller material of compressor at a low cost and improve the durability of the compressor by preparing a work for roller from a seamless, long stretching steel pipe, cutting it into lengths, subjecting to a heat treatment and machining, and thus fabricating a roller. CONSTITUTION:A rotary compressor 1 uses a compressive gas as refrigerant 1, 1, 1. 2 tetrafluoroethane and is composed of a shaft 2, roller piston 6 mounted to the eccentric part of the shaft 2, cylinder 4 accommodating the roller piston 6, and vane 5 which is accommodated in a groove provided in the cylinder 4 and whose foremost is to be in slide contact with the periphery of the-roller piston 6. A seamless, long stretching steel pipe is used as a work 6a, cut into lengths as specified, and subjected to heat treatment and machining incl. grinding, and thus roller piston 6 is fabricated. Thereby the durability of the roller can be enhanced with no more man-hours for processing than according to conventional techniques, and also the durability of the resultant rotary compressor even using R134a having infeior lubricating performance be improved at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Applications Prior Art In recent years, refrigeration equipment and air conditioners have been using difluorodichloromethane, a refrigerant with chlorine in its molecules, which has been used in the past due to environmental problems such as ozone layer depletion. Consideration is being given to changing the refrigerant 1.1.1.2 tetrafluoroethane (hereinafter referred to as R134a) from the refrigerant 1.1.1.2 tetrafluoroethane (hereinafter referred to as R134a), which does not have chlorine in its molecule, from refrigerants such as R12 (hereinafter referred to as R12) and difluorochloromethane (hereinafter referred to as R22). However, the refrigerant that does not have salt N in its molecules has poor lubrication performance, and it is necessary 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.

FIG. 5 shows a sectional view of a conventional compressor. 1 is a compressor. 2 is a shaft, 3 is a roller piston (hereinafter referred to as a roller), 4 is a cylinder, and 5 is a vane. A roller 3 attached to an eccentric portion of a shaft 2 rotated by a motor (not shown) rotates while contacting the inner periphery of the cylinder 4 and the tip of the vane 5, compressing the gas inside the cylinder 4. At this time, the vane 5 reciprocates within the groove of the cylinder 4. Of these sliding parts, the vanes 5 and rollers 3, which have the most severe sliding conditions, are made of high-speed tool steel and cast iron, respectively. Here, the roller 3 was manufactured by using a cast product 3a shown in FIG. 6 as a raw material and subjecting this raw material to heat treatment and machining.

Problems to be Solved by the Invention The combination of vanes made of high-speed tool steel and cast iron rollers as described above does not require the use of conventional refrigerant R12, which has high lubrication performance.
This is based on the assumption that R134a and R22 are dissolved in the lubricating oil of the compressor, and if the refrigerant R134a, which does not contain chlorine in its molecules and has poor lubricating properties, is used, seizures and scratches may occur due to adhesion. occurs, and sufficient characteristics cannot be obtained.

As a result of intensive studies on this point, when refrigerant R134a is used, the sliding surfaces are corroded by hydrofluoric acid, which is a decomposition product of the refrigerant, and seizing and scratching due to adhesion are likely to occur. Therefore, it has been found that if the corrosion resistance of the vane and roller materials, which are subject to particularly severe sliding conditions, is improved, the durability of the sliding parts can be improved even when refrigerant R134a, which has poor lubricity, is used.

However, since the roller has a donut-like hollow shape, if a steel bar material with higher corrosion resistance than a cast product is used as the material for the roller, the machining allowance will be larger than when a cast product is used as the material in the past. The material cost and processing cost are high, making it unsuitable for mass production.Therefore, there has been a desire for a method of manufacturing rollers at low cost, using materials with high corrosion resistance and wear resistance, and with a small machining allowance.

In view of the above problems, the present invention optimizes a method for manufacturing a roller for a compressor using refrigerant R134a, improves the corrosion resistance of the roller material at low cost, and improves the durability of the compressor.

Means for Solving the Problems In order to solve the above problems, in the compressor of the present invention,
The roller material is a long steel pipe shaped like a seamless vibrator.
The roller is manufactured by cutting this into an appropriate length and subjecting it to heat treatment and mechanical processing.

Furthermore, by forming the steel pipe from carbon steel or low alloy steel and lining only the outer peripheral surface with high alloy steel, the corrosion resistance and wear resistance of the roller material can be improved at a lower cost.

Moreover, if an iron boride layer is formed on the outer peripheral surface of the steel pipe and this is used as the material for the roller, the corrosion resistance can be further improved.

Effect The present invention has the above-mentioned structure, and is made of steel material with higher corrosion resistance than cast products, while also using a seamless pipe-shaped material suitable for hollow rollers, so that it can be used as a material for conventional cast products. The roller can be manufactured with approximately the same machining effort as using a roller.

In addition, by lining the outer surface of the steel pipe, which is the raw material for the high-alloy steel upper roller, which has much higher corrosion resistance and wear resistance than cast products, carbon steel, and low-alloy steel, we are able to handle the toughest conditions among rotary compressors. The durability of the roller outer periphery and the sliding part of the vane tip can be further improved, and the material cost can be lowered compared to the case where the entire steel pipe is made of high alloy steel.

In addition, by forming an iron boride layer on the outer circumferential surface of the steel pipe, which has far higher corrosion resistance than metal, and using this as the material for the seven rollers, we have created an iron boride layer that is far more resistant to corrosion than metal. The durability of the sliding parts can be further increased.

By increasing the dimensional accuracy of the inner and outer diameters of the tube through drawing and primary machining in the process prior to forming the iron boride layer, we are able to improve the accuracy of the tube's inner and outer diameters by drawing it out while it is still in the form of a steel tube or through primary machining. It can also be expected to have the effect of reducing the labor involved in machining and handling during the process.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows a sectional view of the compressor of the present invention. 1 is a compressor. 2 is a shaft, 6 is a roller, 4 is a cylinder, and 5 is a vane. A roller 6 attached to an eccentric portion of a shaft 2 rotated by a motor (not shown) is connected to a cylinder 4.
The cylinder 4 rotates while contacting the inner periphery of the cylinder 4 and the tip of the vane 5 to compress the gas inside the cylinder 4. At this time, vane 5 is connected to cylinder 4.
It moves back and forth in the groove. Among these sliding parts, the vane 5, which is subject to the most severe sliding conditions, is made of high-speed tool steel. Here, the roller 6 is made of a chromium-molybdenum copper steel pipe (JIS: 50M435TK) material 6a (hereinafter referred to as material A) shown in FIG. 2 and a chromium-molybdenum copper steel pipe (JIS: 50M435TK) material 6a shown in FIG. (JIS: 5KH51) 7 (hereinafter referred to as material B) and material 6c (hereinafter referred to as material C) in which an iron boride layer is formed on the outer peripheral surface of a carbon copper steel pipe (JIS: STKM16A) shown in Fig. 4. It was manufactured using a total of three types of materials.

The material of the roller 6 and its manufacturing method will be explained in detail below.

Material A shown in Fig. 2 is a seamless steel pipe for machine structures.It is cut into a predetermined length, and after primary processing, heat treatment is performed to adjust the hardness to HRC50, and finishing processing is performed to form the roller of Example 1. Manufactured.

Material B shown in Fig. 3 is a seamless steel pipe for machine structure that is lined with high-speed tool steel on its outer peripheral surface after primary processing.
(approximately 250 μm in thickness) were joined using a powder sintering method, which was cut into a predetermined length, the outer peripheral surface was heat treated to have a hardness of HV800, and then finished to produce the roller of Example 2. did.

Material C shown in Figure 4 is a seamless steel pipe for mechanical structures that is first processed and then an iron boride layer of approximately 100 μm is formed on the outer peripheral surface by the powder poronizing method, and this is cut into a predetermined length. A roller of Example 3 was manufactured by performing a finishing process.

Next, in order to confirm the effects of the rollers using these three types of materials, a corrosion resistance test of the roller alone and a durability test when applied to a rotary compressor were conducted, which will be described below.

In the corrosion resistance test f, in order to evaluate the corrosion resistance of the roller against hydrofluoric acid, which is thought to occur when the refrigerant decomposes, a test piece made in the same manner as the outer circumferential surface of the roller material was tested with 3% fluoride. Soak in hydrogen acid aqueous solution and heat at 40°C.
After standing for a period of time, the corrosion loss (in terms of volume) was measured. In addition, the rotary compressor to which the above roller was applied was tested using compressed gas R134a, polypropylene glycol synthetic refrigeration oil, compressor upper temperature 130°C, suction pressure 1kg/cm2 (gauge pressure), and discharge pressure 20kg.
/cm2 (gauge pressure) for three months, the amount of wear on the outer periphery of the roller was measured to confirm the effect in an actual machine. The results of these corrosion resistance tests and actual machine tests are shown in the table.

table Roller durability test results * Relative value is shown when material B is set to 10.

As shown in the table, the rollers manufactured from materials A and B%C using seamless steel pipes for machine structures in this example have a lower corrosion weight than the conventional example made from spun products. It can be seen that both the test wear amount was small and the durability was improved. Here, this Example 2, which uses material B whose outer peripheral surface is lined with high-alloy steel, has better corrosion resistance and resistance than this Example 1, which uses material A which is still made of chromium-molybdenum copper, which is a low-alloy steel. It can be seen that it has excellent abrasion resistance. Further, it can be seen that Example 3, which uses material C with an iron boride layer formed on the outer peripheral surface, has the best corrosion resistance, but is slightly inferior in wear resistance compared to Example 2. This is thought to be because the iron boride layer on the outer circumferential surface is Hv2000, which is too hard compared to metal, and as a result, abrasive wear occurred as a result of abrasion of the vane, which was the mating material, and the roller itself was also slightly worn. Therefore, compared to conventional rollers made of cast products, Example 1 of the present invention, which uses material A with a composition equivalent to chromium-molybdenum steel, can improve the corrosion resistance of the roller outer peripheral surface and reduce wear. It was found that by having a hollow, concentric circular sample like a seamless steel pipe, the machining allowance can be kept small and the number of machining steps can be reduced compared to conventional tsuba-zukuri.

In addition, in Example 2, in which the outer peripheral surface is lined with high-speed tool steel, corrosion resistance and wear resistance can be further improved compared to Example 1, and the entire roller material is made of expensive high-speed tool steel. It was found that the material cost can be reduced compared to the conventional method.

In addition, it was found that in Example 3, in which an iron boride layer was further formed on the outer peripheral surface, the corrosion resistance could be further improved compared to Examples 1 and 2. Because it was made of steel, the iron boride layer on the outer periphery of the roller was harder, causing wear on the vane side, resulting in more wear than in Example 2. However, by selecting an appropriate material for the vane, this implementation was possible. It is believed that the excellent corrosion resistance of Example 3 can be utilized to further improve the durability of the vane and roller sliding parts. In addition, since the powder poronizing method causes deformation on the treated surface, the deformation can be minimized by performing the primary processing on the steel pipe sample and applying powder boronizing only on the outer peripheral surface, as was done in Example 3. ,
As a result, it was found that the number of finishing steps was reduced compared to the method of applying treatment to the entire surface of a single roller.

Effects of the Invention As described above, according to this embodiment, the durability of the roller can be improved with fewer processing steps than before by making the roller using seamless steel f, which has higher corrosion resistance than conventional casting products. I can do it. Therefore, the durability of a rotary compressor using R134a, which has poor lubricity, can be improved at low cost.

In addition, by manufacturing rollers using low-alloy seamless steel pipes with a high-alloy steel lining on the outer circumferential surface, the rollers can be made at a lower cost and have better corrosion resistance than when using high-alloy seamless steel pipes. and wear resistance can be further improved. Therefore, R with poor lubricity
The durability of a rotary compressor using 134a can be further improved at low cost.

Further, by manufacturing the roller using a seamless steel pipe with an iron boride layer formed on the outer peripheral surface, corrosion resistance can be improved more than when using a seamless steel pipe as a material. Therefore, the durability of a rotary compressor using R134a, which has poor lubricity, can be further improved at low cost.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a compressor according to an embodiment of the present invention, FIG. 2 is a perspective view of material A of a roller piston of a compressor according to an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a perspective view of material C of a roller piston of a compressor according to an embodiment of the present invention, FIG. 5 is a sectional view of a conventional compressor, and FIG. The figure is a perspective view of a cast product that is a raw material for a roller piston of a conventional compressor. 1...Compressor, 2...Shaft, 4.
・・・・・・Cylinder, 5・・・Vane, 6・Old・
・Roller piston. Name of agent: Patent attorney Akira Okaji, 2 people.
Ice ln Control 2- Shimaki Fut 4- Cylinder 5- Vane 6- Row 0 stone diagram m diagram h

Claims (3)

[Claims] (1) The gas to be compressed is refrigerant 1, 1, 1, 2 tetrafluoroethane, and the components of the compressor include a shaft and a roller piston attached to the eccentric part of the shaft;
A method for manufacturing a roller piston in a rotary compressor, comprising: a cylinder that accommodates the roller piston; and a vane that is accommodated in a groove of the cylinder and whose tip portion slides on the outer periphery of the roller piston, Manufacture of a roller piston for a rotary compressor, characterized in that the roller piston is manufactured by using a pipe-shaped long steel pipe as a material, cutting it into a predetermined length, and then subjecting it to mechanical processing such as heat treatment, grinding, and polishing. Method. (2) A steel pipe is formed of carbon steel or low alloy steel, and its outer peripheral surface is lined with high alloy steel having high corrosion resistance and wear resistance, and this is used as the material of the roller piston. (1) A method for manufacturing a roller piston for a rotary compressor according to the above. (3) The method for manufacturing a roller piston for a rotary compressor according to claim (1), characterized in that an iron boride layer is formed on the outer circumferential surface of a steel pipe, and this is used as a material for the roller piston.