JP2008190490A - Swash plate type compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable swash plate type compressor capable of maintaining required sliding performance even during an occurrence of a shortage of lubricating oil supply and positively preventing seizure between a swash plate, a shoe, and a piston. <P>SOLUTION: This swash plate type compressor is equipped with the swash plate slantly disposed with respect to a main shaft of a compressor and rotating with the main shaft, the shoe in sliding contact with the swash plate, and the piston holding the shoe and to which reciprocating motion converted from rotational motion of the main shaft via the shoe is transmitted. A plated layer containing zinc as the main component is provided to one of a piston concave spherical part for holding the shoe and a shoe protruded spherical part engaged with the piston concave spherical part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a swash plate compressor, and more particularly, to a structure of an engaging portion between a shoe slidably contacting a swash plate and a piston holding the shoe.

  A swash plate that is inclined with respect to the main shaft of the compressor and rotates with the main shaft, a shoe (a pair of shoes) slidably in contact with the swash plate, and a rotational movement of the main shaft through the shoe that holds the shoe. A swash plate type compressor having a piston to which a converted reciprocating motion is transmitted is known, and the swash plate type compressor includes a fixed capacity type swash plate type compressor having a constant inclination angle with respect to the main axis of the swash plate, and And a variable displacement swash plate compressor having a variable inclination angle. In this kind of swash plate compressor, usually, a pair of shoes arranged on both sides on the outer peripheral side of the evening is held in a recess formed at the end portion on the non-compression side of the piston, and the recess is formed into a concave spherical surface. There is known a structure in which a held portion of a corresponding shoe is formed into a convex spherical surface.

In general, the engagement portion between the shoe and the piston is required to be lubricated to prevent seizure or the like. In order to maintain good lubrication performance, for example, Patent Document 1 discloses a swash plate type compression that employs a structure in which lubricating oil is easily supplied to the shoe sliding surface by providing a convex portion on the shoe sliding surface on the piston side. An engagement structure between a piston and a shoe of the machine is disclosed. In the case of a compressor used in a refrigeration cycle, the lubricating oil is usually supplied in the form of an oil-containing refrigerant. When the refrigerant flows into the crank chamber in which the swash plate is accommodated, the lubricating oil is also related to the above. It is supplied to the joint.
JP 2000-179454 A

However, the following problems remain in the prior art as described above.
That is, when the refrigerant in the compressor becomes a liquefied state, there may occur a phenomenon in which the lubricating oil adhering to the shoe sliding portion of the piston is washed away by the liquefied refrigerant. When the compressor is operated in this state, there is a possibility that the supply of lubricating oil will be insufficient, and there is a possibility that seizure will occur between any of the swash plate / shoe / piston due to the insufficient supply of lubricating oil.

  Therefore, the object of the present invention is to pay attention to such a problem, particularly when the sliding surface between the piston and the shoe has a so-called self-lubricating property and a shortage of lubricating oil supply occurs. Another object of the present invention is to provide a highly reliable swash plate compressor that can maintain necessary sliding performance and can reliably prevent the occurrence of seizure between swash plates / shoes / pistons.

  In order to solve the above-described problems, a swash plate compressor according to the present invention includes a swash plate that is arranged to be inclined with respect to a main shaft of the compressor, rotates with the main shaft, a shoe that is in sliding contact with the swash plate, and the shoe. In the swash plate type compressor having a piston that holds the shoe and transmits the reciprocating motion converted from the rotational motion of the main shaft through the shoe, the piston concave spherical portion that holds the shoe and the piston concave spherical portion It is characterized in that a plating layer containing zinc as a main component is provided on either one of the convex convex spherical surface portions.

  That is, by providing a plating layer mainly composed of zinc, it becomes possible to provide excellent self-lubricating performance between the piston concave spherical surface portion and the shoe convex spherical surface portion, resulting in a slight shortage of lubricating oil supply. Even in this case, it is possible to maintain the lubrication performance necessary for this part. The shoe and piston are engaged by a convex spherical surface and a concave spherical surface, and the shoe can be freely rotated with respect to the piston side. Therefore, the posture of the shoe with respect to the swash plate has the least resistance, and galling occurs. Since it is automatically maintained in a difficult posture, by providing excellent self-lubricating performance to the above parts, a highly reliable slide that reliably prevents the occurrence of seizure between the swash plate / shoe / piston after all. Dynamic performance will be obtained.

  In the swash plate compressor according to the present invention, it is preferable that the softening point of the plating layer is lower than the softening points of the surface material on the piston side and the shoe side. This makes it possible to prevent or reduce seizure of metal materials even when the lubricating oil is relatively large and insufficient and the temperature of the sliding portion rises.

  Moreover, the form by which the corrosion prevention film is provided to the surface of the said plating layer is also employable. In the plating layer mainly composed of zinc, so-called white rust may be generated. When white rust is generated, the low softening point characteristic of the plating layer mainly composed of zinc is impaired, and the above metal material There is a risk that the anti-seizure performance between the two may be impaired. However, if a corrosion-preventing coating is provided, it is possible to more reliably prevent the occurrence of such white rust, and the low softening point characteristics of the plating layer mainly composed of zinc are more reliably maintained. The

  Such a corrosion-preventing coating can be formed from, for example, a higher fatty acid, a higher fatty acid ester, a higher alcohol, a heavy metal compound, a surfactant, or a combination thereof.

  Among these, as the heavy metal compound, for example, any of chromate, dichromate, and chromium oxide can be used. Moreover, as said surfactant, any of metal soap, phthalocyanine, and polyoxyalkylene glycol can be used, for example.

  Such a swash plate compressor according to the present invention is suitable for a compressor used for a vehicle air conditioner, which requires particularly high reliability and high durability over a long period of time. Further, in order to solve the above-described problems in the prior art, the present invention is suitable for a compressor that compresses a lubricant-containing refrigerant.

  The present invention can be applied to both a fixed displacement swash plate compressor and a variable displacement swash plate compressor.

  According to the swash plate compressor according to the present invention, it is possible to improve the lubricity of the sliding surface between the piston and the shoe when the lubricating oil supply is insufficient, thereby causing seizure or the like between the swash plate / shoe / piston. Can be reliably prevented, and a highly reliable compressor can be provided.

  In addition, the present invention can be implemented without substantially changing the design of the conventional specifications of parts (for example, shoes and pistons), so that it is not necessary to significantly change the conventional production equipment and maintain excellent productivity. However, it can be implemented easily and inexpensively.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a swash plate / shoe / piston engagement portion in a swash plate compressor according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a disk-like swash plate that is arranged to be inclined with respect to a main shaft (not shown) of the compressor and rotates together with the main shaft. A pair of shoes 2 is arranged, and the pair of shoes 2 is configured so that the flat surface side thereof is in sliding contact with the swash plate 1. These shoes 2 have a shoe convex spherical surface portion 2 a, and the shoe convex spherical surface portion 2 a is engaged with a piston concave spherical surface portion 3 a formed on the piston 3 side, so that the piston 3 is opposed to the swash plate 1. The pair of shoes 2 is held in a predetermined positional relationship. Through the pair of shoes 2, the rotational movement of the swash plate 1 is converted into the reciprocating movement of the piston 3 indicated by an arrow so that the piston 3 can perform a predetermined compression operation. A plating layer 4 mainly composed of zinc is provided on either the piston concave spherical surface portion 3a for holding the shoe 2 or the shoe convex spherical surface portion 2a engaged with the piston concave spherical surface portion 3a. In the aspect, the plating layer 4 is provided on the piston concave spherical surface portion 3a.

  It is preferable that the material of each part of the plating layer 4 is selected such that the softening point thereof is lower than the softening points of the surface material on the piston side and the shoe side. 4, the piston 3 may be made of an aluminum alloy having a higher softening point, and the shoe 2 may be made of steel having a higher softening point. Further, as described above, the surface of the plating layer 4 can be provided with a corrosion-preventing coating, and various types of coating as described above can be used.

  In order to confirm the effect of providing a plating layer mainly composed of zinc as described above, the following test was performed. The test assumes a steel shoe and an aluminum alloy piston, and an aluminum alloy and steel in the absence of lubricating oil, assuming a zinc-based plating layer interposed between them. The seizure property between the two was evaluated.

  2, three hemispherical shoes 11 (made of bearing steel) are placed on the fixing jig 13 in the test chamber 12 of the friction wear tester 10 (the contact surface with the disk 14 is the contact surface of the shoe 11). Flat surface side). The disk 14 (aluminum alloy base material) is fixed to the rotary shaft 15 of the friction wear tester 10. After the inside of the test chamber 12 is sealed, the inside of the test chamber 12 is evacuated and the internal air is deaerated. Next, HFC134a (1.1.1.2-tetrafluoroethane) as a refrigerant is introduced into the test chamber 12, and the atmospheric pressure of the HFC134a is set to 0.1 MPa. With the inside of the test chamber 12 sealed, the shoe fixing jig 13 is pressed against the disk 14 through the shoe 11 with a load of 10 kgf. The rotating shaft 15 of the friction wear test machine 10 is rotated at a rotation speed of 200 rpm. A load is applied to the jig 13 on which the shoe 11 is placed at a load increase rate of 2 kgf / min, and the rotational speed and load load at which seizure occurs are recorded. The product of the rotation speed and the load at which seizure occurs is calculated as a seizure pV value (kgf * rpm) (the higher the pV value, the higher the seizure resistance). The occurrence of seizure was detected by the friction torque measuring tool 16 including the load cell connected to the jig 13, and the point at which the measured friction torque started to increase rapidly was detected as the seizure occurrence point. In addition, the disk 14 and the shoe 11 at the start of the test are at room temperature, and the temperature of the test piece under test is in good order. In the test, for three shoes 11, when there is no plating layer, when a plating layer mainly composed of zinc is provided on the shoe 11, a corrosion prevention coating (using higher fatty acid) is further applied to the surface of the plating layer. Each case was done.

  As shown in Table 1 and FIG. 3, the test results were extremely low pV values when there was no plating layer, but the pV value was significantly higher when a plating layer mainly composed of zinc was provided. When the corrosion prevention coating was further applied, the pV value was further increased. In this way, it is confirmed that by providing a plating layer mainly composed of zinc according to the present invention, it is possible to provide excellent self-lubricating performance when lubricating oil is insufficient, thereby greatly improving lubricity. It was done.

  The swash plate compressor according to the present invention can be applied to both a fixed displacement swash plate compressor and a variable displacement swash plate compressor, and is particularly suitable as a compressor for a vehicle air conditioner that compresses a lubricant-containing refrigerant. Is.

It is a schematic sectional drawing of the engaging part of the swash plate / shoe / piston in the swash plate type compressor which concerns on one embodiment of this invention. It is a schematic block diagram of the test apparatus used for the test done in order to confirm the effect by this invention. It is a comparison characteristic figure of pV value which shows a test result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Swash plate 2 Shoe 2a Shoe convex spherical surface part 3 Piston 3a Piston concave spherical surface part 4 Plating layer which has zinc as a main component

Claims (8)

  A swash plate that is inclined with respect to the main shaft of the compressor and rotates with the main shaft, a shoe that is slidably contacted with the swash plate, and a reciprocating motion that holds the shoe and is converted from the rotational motion of the main shaft through the shoe. In a swash plate compressor having a piston to which motion is transmitted, zinc is a main component in one of a piston concave spherical surface portion that holds the shoe and a shoe convex spherical surface portion that engages the piston concave spherical surface portion. A swash plate type compressor provided with a plating layer.   The swash plate type compressor according to claim 1, wherein a softening point of the plating layer is lower than a softening point of a surface material on a piston side and a shoe side.   The swash plate type compressor according to claim 1, wherein a corrosion prevention coating is provided on a surface of the plating layer.   The swash plate compressor according to claim 3, wherein the corrosion-preventing coating is formed of any one of a higher fatty acid, a higher fatty acid ester, a higher alcohol, a heavy metal compound, a surfactant, or a combination thereof.   The swash plate compressor according to claim 4, wherein the heavy metal compound is made of any one of chromate, dichromate, and chromium oxide.   The swash plate compressor according to claim 4, wherein the surfactant is made of any one of metal soap, phthalocyanine, and polyoxyalkylene glycol.   The swash plate type compressor according to any one of claims 1 to 6, which is used for a vehicle air conditioner.   The swash plate type compressor according to any one of claims 1 to 7, wherein the lubricant-containing refrigerant is compressed.

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