KR100312933B1 - Reciprocating Compressor - Google Patents

Abstract

The compressor has cylinder blocks 30 and 31 having cylinder bores 41 and 42. The drive shaft 39 is rotatably supported by the cylinder blocks 30 and 31. The swash plate 40 is rotatably mounted to the drive shaft 39 integrally. The piston 1 is slidably accommodated in the cylinder bores 41 and 42. The shoe 44 is slidably arranged between the piston 1 and the swash plate 40. As the swash plate 40 rotates, the piston 1 reciprocates through the shoe 44. The piston 1 is formed from aluminum or an aluminum alloy as a base material. The piston 1 is provided with the holding recess 2 which slidably holds the shoe 44. The holding | maintenance recessed part 2 is provided with the coating layer 6 which mainly consists of tin.

Description

Reciprocating Compressor

In general, a reciprocating compressor such as shown in FIG. 10 is known as a compressor used for an air conditioner such as an automobile. This compressor is provided with a pair of cylinder blocks 30 and 31 joined to each other. The swash plate chamber 32 is formed between both cylinder blocks 30 and 31. Housing 35 and 36 are joined to the outer end surface of each cylinder block 30 and 31 via valve board 33 and 34, respectively. The suction chamber 36 and the discharge chamber 37 are formed between the valve plates 33 and 34 and the housings 35 and 36.

The drive shaft 39 is rotatably supported by both cylinder blocks 30 and 31. The swash plate 40 as the cam is fixed to the drive shaft 39 in the swash plate chamber 32. A plurality of pairs of cylinder bores 41, 42 are formed in each cylinder block 30, 31 around the drive shaft 39. The double head piston 43 is accommodated in each pair of cylinder bores 41 and 42, respectively. A shoe 44 as a cam follower is disposed between the swash plate 40 and the piston 43. The shoe 44 has a slide surface 45 which slides on the front and rear surfaces of the swash plate 40 and a spherical surface 47 which is slidably joined to the holding recess 46 of the piston 43.

In the compressor, when the swash plate 40 rotates as the drive shaft 39 rotates, the piston 43 reciprocates in the cylinder bores 41 and 42 through the shoe 44 by the action of the swash plate 40. do. At this time, as the piston 43 moves from the top dead center to the bottom dead center, the refrigerant gas is sucked into the cylinder bores 41 and 42 from the suction chamber 37. As the piston 43 moves from the bottom dead center to the top dead center, the refrigerant gas sucked into the cylinder bores 41 and 42 is compressed and discharged into the discharge chamber 38.

In general, in order to increase the discharge capacity of the compressor, it is considered to enlarge the cylinder bores 41 and 42 and to enlarge the piston 43, the swash plate 40 and the shoe 44 accordingly. Normally, the piston 43 and the swash plate 40 are formed of a lightweight aluminum alloy or the like, but sticking is likely to occur between metals of the same type by sliding. For this reason, the shoe 44 arrange | positioned between the piston 43 and the swash plate 40 is formed with the iron metal in order to prevent sticking with the piston 43 and the swash plate 40. As shown in FIG. However, since the iron-based metal has a specific gravity, when the shoe 44 is enlarged, the weight of the entire compressor increases.

In order to increase the discharge capacity temporarily, only the piston 43 and the swash plate 40 are enlarged without changing the size of the shoe 44. However, when the discharge capacity increases, the load acting on the swash plate 40 through the shoe 44 in the piston 43 also increases. For this reason, if only the size of the shoe 44 is the same, the load per unit area acting on the spherical surface 47 and the slide surface 45 of the shoe 44 becomes large. As a result, the slide resistance between the spherical surface 47 of the shoe 44 and the retaining recess 46 of the piston 43 and the slide resistance between the slide surface 45 and the swash plate 40 of the shoe 44 increase. do.

When the slide resistance between the spherical surface 47 of the shoe 44 and the retaining recess 46 of the piston 43 increases, the shoe 44 can move smoothly along the inner surface of the retaining recess 46. There will be no. Since the shoe 44 is moved in the holding recess 46 by the swash plate 40, if the shoe 44 does not move smoothly, the shoe 44 is between the slide surface 45 of the shoe 44 and the swash plate 40. The acting load increases, and the sliding resistance between the slide surface 45 and the swash plate 40 further increases.

In the compressor, refrigerant gas from an external refrigerant circuit is introduced into the suction chamber 37 through the swash plate chamber 32. By introducing the refrigerant gas into the swash plate chamber 32, each mechanism in the swash plate chamber 32 is cooled, and the pulsation generated by the suction of the refrigerant gas into the cylinder bores 41 and 42 is prevented. However, at present, due to the ozone layer destruction problem in the stratosphere, R134a (CF ₃ CH ₂ F) which does not contain chlorine in the molecule is employed as the refrigerant gas. Chlorine has properties as extreme pressure additives. Extreme pressure additives are substances that react with the surface of a metal to form a metal compound film and thereby reduce the frictional resistance. When the refrigerant gas introduced into the swash plate chamber 32 washes away the lubricating oil remaining on the surface of the swash plate 40 or the like by the washing action of the swash plate chamber 32, the piston in contact with the shoe 44 and the shoe 44 ( 43) and the swash plate 40 are not lubricated well. In such a case, if there is no chlorine acting as an extreme pressure additive in the molecules of the refrigerant gas, the slide resistance becomes very large.

It is an object of the present invention to provide a reciprocating compressor which can reduce the slide resistance generated at the connection portion of the cam and the piston.

The present invention relates to a reciprocating compressor for converting rotation of a drive shaft into a reciprocating motion of a piston through a cam, and more particularly, to a structure for reducing a sliding resistance generated at a connection portion of a cam and a piston. will be.

BRIEF DESCRIPTION OF THE DRAWINGS It is an enlarged sectional view of the principal part which shows the swash plate compressor of 1st Embodiment which embodied this invention.

2 is a perspective view showing a piston in the first embodiment;

3 is an enlarged sectional view of an essential part of the piston;

4 is a graph showing a measurement result of the sticking time in the first embodiment.

5 is an enlarged sectional view of an essential part showing a swash plate compressor of a second embodiment of the present invention.

FIG. 6 is a graph showing a measurement result of a sticking time in a second embodiment. FIG.

7 is a sectional view showing a web cam compressor in another embodiment of the present invention.

8 is an enlarged sectional view of an essential part showing a cam follower in another embodiment of the present invention;

9 is an enlarged cross-sectional view of a main part showing a swash plate in another embodiment of the present invention;

10 is a cross-sectional view showing a conventional swash plate compressor.

In order to achieve the above object, the compressor of the present invention is provided with a cylinder block having a cylinder bore. The drive shaft is rotatably supported by the cylinder block. The cam is rotatably mounted to the drive shaft. The piston is slidably received in the cylinder bore. The cam follower is slidably disposed between the piston and the cam. As the cam rotates, the piston reciprocates through the cam follower. The piston is formed based on aluminum or an aluminum alloy. The piston has a holding part for slidably holding the cam follower. The holding part of the piston is provided with a coating layer mainly composed of tin.

Therefore, according to the present invention, the slide resistance between the piston retainer and the cam follower is reduced by the coating layer provided on the piston retainer. For this reason, even when a lack of lubricant arises in a compressor, a cam follower part moves smoothly in the holding part of a piston. Thus, the cam can move the cam follower with a small force. As a result, the load acting between the cam follower and the cam is reduced, and the slide resistance between the cam follower and the cam is reduced.

(1st embodiment)

EMBODIMENT OF THE INVENTION Hereinafter, 1st Embodiment of the swash plate compressor which embodied this invention is described according to FIG. In addition, the mechanical structure of the compressor of this 1st Embodiment is substantially the same as the compressor shown in FIG. 10 demonstrated by background art. Therefore, the same members as those shown in FIG. 10 are denoted by the same reference numerals, and the description thereof is omitted, and only the parts different from those in FIG. 10 will be described.

As shown in FIGS. 1-3, the compressor of this embodiment differs from the compressor shown in FIG. 10, and is provided with the piston 1 in which the coating layer 6 mainly consisting of tin was formed in the whole surface. This piston 1 is provided with a pair of holding recesses 2 which slidably hold the spherical surface 47 of the shoe 44.

The piston 1 is comprised from the main body 5 which uses aluminum or an aluminum alloy as a base material, and the coating layer 6 formed in the whole surface of the main body 5. As the aluminum alloy, for example, an Al-Si alloy or an Al-Si-Cu alloy may be appropriately used. In particular, as the base material of the main body 5, an aluminum alloy containing hard particles is preferable. Representative of such an aluminum alloy is an aluminum-silicon alloy. Aluminum-silicon alloys contain about 10-30% by weight of silicon. If the aluminum-silicon alloy has a silicon content of less than or equal to the process composition, the silicon exists as process silicon (ie, hard particles). In this first embodiment, as shown in FIG. 3, the main body 5 of the piston 1 is formed with an aluminum-high silicon alloy 4 containing 12% by weight of silicon 3 as a base material.

Other materials containing hard particles include Al-Mn intermetallic compounds, Al-Si-Mn intermetallic compounds, Al-Fc-Mn intermetallic compounds, and Al-Cr intermetallic compounds. You may use as a base material.

In this first embodiment, the shoe 44 is formed of a SUJ2 material (high carbon chromium bearing steel material) specified in JIS, and the swash plate 40 is formed of an aluminum-silicon alloy.

In the piston 1 used for the compressor of the first embodiment, for example, it is possible to select and use appropriately from among the various coating layers 6 shown in Examples 1 to 9, below. Hereinafter, the piston 1 of Examples (1)-(9) will be described sequentially. In addition, the structure of the main body 5 of the piston 1 of Examples (1)-(9) is the same, and only the structure of the coating layer 6 differs.

(Example ①)

The piston 1 of Example ① has the coating layer 6 which consists of a vacancy plating layer of tin and copper. This coating layer 6 is formed as follows. That is, an aqueous solution containing 6% by weight of potassium stannate and 0.012% by weight of copper gluconate is maintained at 60 to 80 ° C, and the whole body 5 of the piston 1 is immersed in the aqueous solution for about 3 minutes. Electroless plating is performed on the surface of (5). Thereafter, the main body 5 is taken out of an aqueous solution and washed with water. As a result, tin and copper are vacant-plated on the entire surface of the piston 1 including the shoe 44 and the sliding retaining recesses 2 to form the coating layer 6. This coating layer 6 is a composition containing 97 weight% tin and 3 weight% copper, and its thickness is 1.2 micrometers.

(Example ②)

The piston 1 of Example ② has a coating layer 6 made of a vacancy-plated layer of tin and nickel. In other words, by using an aqueous solution containing 6% by weight of potassium stannate and 0.005% by weight of nickel chloride, tin is applied to the entire surface of the piston 1 including the holding recesses 2 in the same manner as in the above example ①. And nickel are plated by vacancy, and the coating layer 6 is formed. This coating layer 6 is a composition containing 98 weight% tin and 2 weight% nickel, and the thickness is 1 micrometer.

(Example ③)

The piston 1 of Example ③ has the coating layer 6 which consists of a vacancy plating layer of tin and zinc. In other words, by using an aqueous solution containing 6% by weight of potassium stannate and 0.005% by weight of zinc sulfate, tin and zinc are deposited on the entire surface of the piston 1 including the holding recesses 2 in the same manner as in Example 1). Vacancies are plated to form the coating layer 6. This coating layer 6 is a composition containing 97 weight% of tin and 3 weight% of zinc, and its thickness is 1 micrometer.

(Example ④)

The piston 1 of Example 4 has the coating layer 6 which consists of a vacancy plating layer of tin and lead. In other words, by using an aqueous solution containing 6% by weight of potassium stannate and 0.007% by weight of lead sulfate, tin and lead are applied to the entire surface of the piston 1 including the holding recesses 2 in the same manner as in Example 1). This vacancies are plated and the coating layer 6 is formed. This coating layer 6 is a composition containing 95 weight% tin and 5 weight% lead, and its thickness is 2 micrometers.

(Example ⑤)

The piston 1 of Example 5 has the coating layer 6 which consists of a vacancy plating layer of tin and indium. That is, by using an aqueous solution containing 6% by weight of potassium stannate and 0.005% by weight of indium sulfate, tin and indium are formed on the entire surface of the piston 1 including the holding recesses 2 in the same manner as in the above example ①. This vacancies are plated and the coating layer 6 is formed. This coating layer 6 is a composition containing 97 weight% tin and 3 weight% indium, and its thickness is 1 micrometer.

(Example ⑥)

The piston 1 of Example 6 has the coating layer 6 which consists of a plating layer of tin alone. That is, by using the aqueous solution containing 6 weight% of potassium stannate, the coating layer 6 which consists of a plating layer of tin alone on the whole surface of the piston 1 containing the holding recessed part 2 similarly to said Example (1). Is formed. The thickness of this coating layer 6 is 1.5 micrometers.

(Example ⑦)

The piston 1 of Example 7 has the coating layer 6 which contains the fluororesin powder as a solid lubricant as a vacancy plating layer of tin and copper. Namely, by using an aqueous solution containing 6% by weight of potassium stannate, 0.003% by weight of copper gluconate, and 1.0% by weight of fluorine resin powder, the piston including the holding concave portion 2 in the same manner as in Example (1) above ( The coating layer 6 which consists of fluororesin powder in the vacancy plating layer of tin and copper is formed in the whole surface of 1). This coating layer 6 is a composition containing 99 weight% tin, 0.9 weight% copper, and 0.1 weight% fluorine resin powder, and the thickness is 1.4 micrometers.

(Example ⑧)

The piston 1 of Example 8 has the coating layer 6 which consists of a tin and copper vacancies plating layer like Example 7 above, but after the coating layer 6 is formed by the chemical plating process similarly to Example ①, The coating layer 6 is subjected to heat treatment at a temperature of 150 ° C. for 1 hour.

(Example ⑨)

The piston 1 of Example 9 has the coating layer 6 which consists of a vacancy plating layer of tin, copper, and zinc. Namely, by using an aqueous solution containing 6% by weight of potassium stannate, 0.003% by weight of copper gluconate, and 0.003% by weight of zinc sulfate, the piston including the holding recesses 2 in the same manner as in the above example ① The coating layer 6 which consists of a vacancy plating layer of tin, copper, and zinc is formed in the whole surface of). This coating layer 6 is a composition containing 97 weight% tin, 1.5 weight% copper, and 1.5 weight% zinc, and its thickness is 1.2 micrometers.

The inventors of the present application performed the following tests in order to confirm the anti-sticking performance of the respective compressors provided with the pistons 1 of Examples 1 to 9, respectively. This test measures the time required for the swash plate 40 and the shoe 44 to stick when each compressor assembled in the vehicle air conditioner is operated under severe conditions (smooth oil is not present in the compressor). In this test, each compressor was operated continuously under the condition that the suction pressure was -0.5 kg / cm ² , the discharge pressure was 3 kg / cm ² , and the rotational speed of the drive shaft 39 was 1000 rpm. In this test, one formed of a SUJ2 material specified in JIS was used as the shoe 44 of the compressor, and one formed of an aluminum-silicon alloy was used as the swash plate 40 of the compressor. For this test, a piston formed of only an aluminum-silicon alloy 4 containing 12% by weight of silicon 3, that is, a piston without the coating layer 6 was used as a comparative example, and the compressor in which the piston was assembled was used. The same test was done for.

4 is a graph showing the results of this test. The test result shown in FIG. 4 shows that the compressor employing the piston 1 of Examples 1 to 9 with the coating layer 6 is compared with the compressor employing the shoe 44 even under severe use conditions compared to the compressor employing the piston of the Comparative Example. It is shown that sticking of the swash plate 40 is unlikely to occur. In particular, it was found that the compressor employing the piston 1 of Example ① having the coating layer 6 made of tin and copper vacancy plating layer had the best anti-sticking performance.

As mentioned above, in this 1st Embodiment, the coating layer 6 mainly having tin is formed in the surface of the piston 1. As shown in FIG. Tin is a material with self-lubricating action. For this reason, even if the slide resistance between the holding recessed part 2 of the piston 1 and the spherical surface 47 of the shoe 44 is reduced, and the lack of oil smoothly occurs in a compressor, the shoe 44 Moves smoothly along the inner surface of the holding recess 2. Therefore, the swash plate 40 can move the shoe 44 in the holding recess 2 with a small force. As a result, the load acting between the slide surface 45 and the swash plate 40 of the shoe 44 is reduced, and the slide resistance between the slide surface 45 and the swash plate 40 is reduced. For this reason, when increasing the discharge capacity of a compressor, even if only the piston 1 and the swash plate 40 are enlarged without changing the size of the shoe 44, the problem by the increase of a slide resistance does not arise.

The coating layer 6 is formed in the whole surface of the piston 1. For this reason, the slide resistance between the outer peripheral surface of the piston 1 and the inner peripheral surfaces of the cylinder bores 41 and 42 is reduced, and the piston 1 can move smoothly into the cylinder bores 41 and 42.

By containing at least one metal selected from copper, nickel, zinc, lead and indium into the coating layer 6 mainly composed of tin, the coating layer 6 is densified and a hard metal compound is coated with the coating layer 6. The coating layer 6 is reinforced by being dispersed in the inside. As a result, the reduction of the friction coefficient and the improvement of the wear resistance can be further improved. For example, when copper is contained in the coating layer 6 mainly composed of tin, the coating layer 6 is densified, and hard tin copper compound (Cu ₆ Sn ₅ ) is dispersed in the coating layer 6, and the coating layer is included. (6) is strengthened.

The coating layer 6 is formed by the chemical plating method. According to the chemical plating method, other metals such as tin and copper can be easily vacant and a solid lubricant such as fluororesin powder can be put into the coating layer 6.

(2nd embodiment)

Next, a second embodiment of the swash plate type compressor in which the present invention is embodied will be described based on FIGS. 5 and 6. In addition, the mechanical structure of the compressor of this 2nd Embodiment is substantially the same as the compressor shown in FIG. 10 demonstrated by background art. Therefore, the same members as those shown in FIG. 10 are denoted by the same reference numerals, and the description thereof is omitted, and only the parts different from the compressor of FIG. 10 will be described.

As shown in FIG. 5, the compressor of the present embodiment is different from the compressor shown in FIG. 10, and includes a shoe 7 having a coating layer 11 mainly composed of tin on the entire surface. The main body 12 of this shoe 7 is formed of the SUJ2 material prescribed | regulated by JIS. The shoe 7 has a spherical surface 8 slidably engaged with the holding recess 46 of the piston 43 and a slide surface 10 that slides on the surfaces before and after the swash plate 40. The spherical surface 8 of the shoe 7 has a spherical surface portion 9 having a radius larger than that of other portions in the center portion. An oil reservoir for retaining lubricating oil is formed between the spherical surface 9 and the retaining recess 46 of the piston 43. The slide surface 10 of the shoe 7 has a slightly expanded shape, and lubricating oil is formed of an aluminum-silicon alloy of the slide surface 10, the swash plate 40, and the piston 43.

As the shoe 7 used for the compressor of the second embodiment, for example, it is possible to appropriately select and use from among those having the various coating layers 11 shown in Examples 1 to 9 below. Hereinafter, the shoes 7 of Examples 1 to 9 will be described in turn. In addition, the shoes 7 of Examples 1 to 9 are all the same in structure of the main body 12, and the structure of the coating layer 11 is different. It is only.

(Example ①)

The shoe 7 of Example ① has a coating layer 11 made of a tin and copper vacancy plating layer. This coating layer 11 is formed as follows. That is, the main body of the shoe 7 is immersed in an aqueous solution containing 6% by weight potassium stannate and 0.012% by weight copper gluconate. In this state, the main body 12 is connected to the negative electrode, while the positive electrode is formed of a metal rod having a large tendency to ionize. When a predetermined voltage is applied between both electrodes using an aqueous solution as an electrolyte, tin and copper are precipitated by the electrolytic action and adhered to the surface of the main body 12. Thereafter, the main body 12 is taken out of the aqueous solution and washed. As a result, tin and copper are vacant-plated on the whole surface of the shoe 7, and the coating layer 11 is formed. The shoe 7 after the plating treatment is polished in consideration of the clearance between the swash plate 40 and the piston 43 on which the shoe 7 is disposed, and the uniform coating layer 11 is formed. This coating layer 11 is a composition containing 97 weight% tin and 3% copper, and its thickness is 1.2 micrometers.

(Example ②)

The shoe 7 of Example ② has the coating layer 11 which consists of a vacancy plating layer of tin and nickel. That is, by using an aqueous solution containing 6% by weight of potassium stannate and 0.005% by weight of nickel chloride, tin and nickel were vacantly plated on the entire surface of the shoe 7 in the same manner as in Example 1 above, and the coating layer 11 Is formed. This coating layer 11 is a composition containing 98 weight% tin and 2 weight% nickel, and the thickness is formed in 1 micrometer by surface polishing.

(Example ③)

The shoe 7 of Example ③ has the coating layer 11 which consists of a vacancy plating layer of tin and zinc. In other words, by using an aqueous solution containing 6% by weight of potassium stannate and 0.005% by weight of zinc sulfate, tin and zinc were vacantly plated on the entire surface of the shoe 7 in the same manner as in Example 1 above, and the coating layer 11 was Is formed. This coating layer 11 is a composition containing 97 weight% of tin and 3 weight% of zinc, and the thickness is formed in 1 micrometer by surface polishing.

(Example ④)

The shoe 7 of Example 4 has the coating layer 11 which consists of a vacancy plating layer of tin and lead. That is, by using an aqueous solution containing 6% by weight of potassium stannate and 0.007% by weight of lead sulfate, tin and lead are vacantly plated on the entire surface of the shoe 7 in the same manner as in Example 1 above, and the coating layer 11 Is formed. This coating layer 11 is a composition containing 95 weight% tin and 5 weight% lead, and the thickness is formed in 2 micrometers by surface polishing.

(Example ⑤)

The shoe 7 of Example 5 has the coating layer 11 which consists of a vacancy plating layer of tin and indium. In other words, by using an aqueous solution containing 6% by weight of potassium stannate and 0.005% by weight of indium sulfate, tin and indium were vacantly plated on the entire surface of the shoe 7 in the same manner as in Example 1 above, and the coating layer 11 Is formed. This coating layer 11 is a composition containing 97 weight% of tin and 3 weight% of indium, and the thickness is formed in 1 micrometer by surface polishing.

(Example ⑥)

The shoe 7 of Example 6 has the coating layer 11 which consists of a plating layer of tin alone. That is, by using the aqueous solution containing 6 weight% of potassium stannate, the coating layer 11 which consists of plating of tin alone is formed in the whole surface of the shoe 7 similarly to said Example (1). The thickness of this coating layer 11 is formed to 1.5 micrometers by surface polishing.

(Example ⑦)

The shoe 7 of Example 7 has the coating layer 11 which contains the fluororesin powder as a solid lubricant in the vacancy plating layer of tin and copper. Namely, by using an aqueous solution containing 6% by weight of potassium stannate, 0.003% by weight of copper gluconate, and 1.0% by weight of molybdenum disulfide powder, tin and copper were formed on the entire surface of the shoe 7 in the same manner as in the above example ①. The coating layer 11 containing the molybdenum disulfide powder is formed in the vacancy plating layer of. This coating layer 11 is a composition containing 99 weight% tin, 0.9 weight% copper, and 0.1 weight% molybdenum disulfide powder, and the thickness is 1.4 micrometers by surface polishing.

(Example ⑧)

The shoe 7 of Example (8) is the same as the example (1) above, and has a coating layer (11) consisting of a tin and copper vacancies plating layer. In the same manner as in Example (1), the coating layer 11 is formed by the electrolytic plating treatment and the coating layer thereof. After the surface polishing of (11) is performed, the coating layer 11 is subjected to heat treatment at a temperature of 150 ° C. for 1 hour.

(Example ⑨)

The shoe 7 of Example 9 has a coating layer 11 made of tin, a vacancy plating layer of copper and zinc. In other words, by using an aqueous solution containing 6% by weight of potassium stannate, 0.003% by weight of copper gluconate and 0.003% by weight of zinc sulfate, tin, copper, and The coating layer 11 which consists of a vacancy plating layer of zinc is formed. This coating layer 11 is a composition containing 97 weight% tin, 1.5 weight% copper, and 1.5 weight% zinc, and the thickness is 1.2 micrometers by surface polishing.

The inventors of the present application performed the following tests in order to confirm the anti-sticking performance of each compressor in which the shoes 7 of Examples 1 to 9 were assembled. This test measures the time required for the swash plate 40 and the shoe 7 to stick when operating each compressor assembled in the vehicle air conditioner under severe conditions (with no oil present in the compressor). In this test, each compressor was operated continuously under the condition that the suction pressure was -0.5 kg / cm ² , the discharge pressure was 3 kg / cm ² , and the rotation speed of the drive shaft 39 was 1000 rpm. In this test, as the swash plate 40 and the piston 43 of the compressor, one formed of an aluminum-silicon alloy was used. In addition, about this test, the shoe formed only by SUJ2 material, ie, the shoe without the coating layer 11, was used as a comparative example, and the same test was also performed about the compressor which assembled this shoe.

6 is a graph showing the results of this test. The test results shown in FIG. 6 show that the compressor employing the shoe 7 of Examples 1 to 9 with the covering layer 11 is compared with the compressor employing the shoe of the comparative example, even under the severe use conditions. It is shown that sticking of the swash plate 40 is difficult to occur. In particular, it turns out that the compressor which employ | adopted the shoe 7 of the example (1) provided with the coating layer 11 which consists of a vacancy plating layer of tin and copper is the most excellent in sticking prevention performance.

As described above, in this second embodiment, the coating layer 11 mainly composed of tin is formed on the surface of the shoe 7. For this reason, the slide resistance between the holding recess 46 of the piston 43 and the spherical surface 8 of the shoe 7 is reduced, and at the same time between the swash plate 40 and the slide surface 10 of the shoe 7. Slide resistance is reduced. Therefore, even when there is a lack of smooth oil in the compressor, good lubricity is maintained at the connection portion between the swash plate 40 and the piston 43, and the slide resistance generated at the connection portion is suppressed.

The shoe 7 moves smoothly along the inner surface of the holding recess 46 of the piston 43 by the action of the coating layer 11 provided on the spherical surface 8. As a result, the load acting between the slide surface 10 and the swash plate 40 of the shoe 7 is reduced, which also reduces the slide resistance between the slide surface 10 and the swash plate 40. Since the coating layer 11 is also provided in the slide surface 10 of the shoe 7, the slide resistance between the slide surface 10 and the swash plate 40 is further reduced. Therefore, in the same manner as in the first embodiment, when the discharge capacity of the compressor is increased, the slide resistance is increased even when the piston 32 and the swash plate 40 are enlarged without changing the size of the shoe 7. The problem does not occur.

Since tin not only has excellent lubrication performance but also has an effect of preventing rust, forming a coating layer 11 mainly composed of tin on the surface of a shoe 7 made of an iron-based metal protects the shoe 7 from rust. You may.

The effect produced by containing other metals, such as copper, in the coating layer 11 mainly consisting of tin is the same as that of the said 1st Embodiment.

In addition, this invention is not limited to said each embodiment, For example, it is also possible to change the structure of each part and to actualize as follows.

(1) In the first and second embodiments, the present invention is embodied by a double head piston swash plate compressor, but the discharge capacity can be adjusted by changing the inclination angles of the swash plate piston and swash plate, for example. It may be embodied in a variable displacement compressor or a web cam compressor as shown in FIG. In the web cam compressor shown in Fig. 7, the same members as those shown in Fig. 10 are denoted by the same reference numerals and the description thereof is omitted. As shown in FIG. 7, this web cam type compressor is provided with the web cam 48 which has a cam shape cam surface instead of the swash plate 40 of the compressor shown in FIG. The slide surface 45 of the shoe 44 slides on the cam surfaces before and after the web cam 48.

In such a web cam compressor, the piston 43 reciprocates a plurality of times (two times in FIG. 7) between the rotation of the drive shaft 39, and the shoe 44 is placed on the complicated cam of the web cam 48. Needs to move in accordance with the displacement of the cam surface. For this reason, in the web cam compressor, the slide between the shoe 44 and the piston 43, and the slide between the shoe 44 and the web cam 48 become more severe than in the case of the swash plate type compressor. Therefore, reducing the slide resistance generated at the connection portion between the web cam 48 and the piston 43 becomes important in that the web cam compressor performs a stable compression action.

In the compressor of FIG. 7, the piston 43 is changed to the piston 1 described in the first embodiment in order to reduce the slide resistance generated at the connection portion of the web cam 48 and the piston 43, or the shoe What is necessary is just to change 44 to the shoe 7 demonstrated by the said 2nd Embodiment.

(2) In the first and second embodiments, shoes 7 and 44 having mostly hemispherical shapes are employed as cam followers, but a structure using rollers may be used instead of shoes 7 and 44. Alternatively, as shown in FIG. 8, the slipper 13 which slides the cam follower part onto the swash plate 40 and the ball 14 which engages with the recessed part 13a of the slipper 13 may be comprised. The ball 14 is slidably engaged with the holding recess 46 of the piston 43. In FIG. 8, the same members as those of the compressor shown in FIG. 10 are denoted by the same reference numerals and the description thereof is omitted. In the structure of this FIG. 8, the piston 43 is changed to the piston 1 demonstrated in the said 1st Embodiment, or the shoe 7 in the said 2nd Embodiment in at least one of the slipper 13 and the ball 14 is shown. The coating layer 11 may be implemented.

The configuration of the cam follower shown in FIG. 8 may be applied to the web cam compressor of FIG. 7 described above.

(3) In the first embodiment, as shown in FIG. 9, the coating layer 15 mainly composed of tin is also formed on the slide surface of the swash plate 40 with the shoe 44. The composition of the coating layer 15 is preferably the same as that of the coating layer 6 of the piston 1. In this way, the slide resistance between the swash plate 40 and the shoe 44 is further reduced.

Instead of providing the coating layer 15 on the swash plate 40, a coating layer mainly composed of tin may be provided on the slide surface 45 of the shoe 44. In other words, as the shoe 7 in the second embodiment, one provided with the coating layer 11 only on the slide surface 10 may be used, and the shoe 7 may be used as the shoe in the first embodiment.

(4) In the first embodiment, the coating layer 6 is provided only on the holding recesses 2 of the piston 1.

(5) In the second embodiment, the coating layer 11 is provided only on one of the spherical surface 8 and the slide surface 10 of the shoe 7. When installing the coating layer 11 only in the spherical surface 8 of the shoe 7, you may provide the coating layer 15 in the swash plate 40 as demonstrated in said (3). When installing the coating layer 11 only on the slide surface 10 of the shoe 7, you may use the piston 1 in 1st Embodiment, ie, the piston 1 provided with the coating layer 6.

(6) In the first embodiment, prior to forming the coating layer 6 on the main body 5 of the piston 1, the surface of the main body 5 is treated with an alamide treatment, manganese borate treatment, zinc borate treatment or Performing basic treatment such as zinc plating treatment. In this way, the slide resistance to the shoe 44 is further reduced.

(7) To form the in each embodiment, an alumina ceramic on the slide surface 45 of the shoe 7, the main body 12, the slide surface 10 and the shoe 44 of the (Al ₂ O ₃₎ layer. In this way, the slide resistance with respect to the swash plate 40 is further reduced.

(8) In each said embodiment, changing the coexistence ratio of tin and other metal in the coating layers 6 and 11 suitably according to the performance of the target compressor. For example, when tin and copper coexist, it is preferable to change the content rate of copper in 0.1 weight%-50 weight% of range. If the content of copper is less than 0.1% by weight, the coating layers 6 and 11 are not sufficiently densified and strengthened, and the effect obtained by containing copper is insufficient. If the copper content is greater than 50% by weight, the self-lubricating action of tin is not sufficiently exhibited, and the slide resistance increases.

(9) In each of the above embodiments, carbon powder, boron nitride powder, or the like is used instead of the fluororesin powder or the molybdenum disulfide powder as the solid lubricant contained in the coating layers 6 and 11.

(10) In each of the above embodiments, in the case of forming the coating layers 6 and 11, instead of wet plating methods such as electrolytic plating and chemical plating, dry plating such as CVD or vacuum deposition, sputtering, PVD of ion plating, or the like. You can also use When the solid lubricant described in the above (9) is contained in the coating layers 6 and 11, the composite plating method may be used.

(11) In said each embodiment, changing the thickness of the coating layers 6 and 11 suitably in the range of 1-5 micrometers. If the coating layers 6 and 11 are thinner than 1 micrometer, a friction coefficient cannot be made small enough. If the coating layers 6 and 11 are thicker than 5 micrometers, there exists a possibility that the intensity unreasonability, such as peeling of the coating layers 6 and 11, may arise.

Claims (11)

Cylinder blocks 30 and 31 having cylinder bores 41 and 42, drive shafts 39 rotatably supported by the cylinder blocks 30 and 31, and rotatably integrally with the drive shafts 39; A cam (40; 48) mounted, a piston (1) slidably housed in the cylinder bores (41, 42), and a cam type slidably disposed between the piston (1) and the cam (40; 48) In the reciprocating compressor having an eastern portion 44; 13, 14, and the piston 1 reciprocates through the cam followers 44; 13, 14 in accordance with the rotation of the cam 40; 48, The piston 1 is formed of aluminum or an aluminum alloy as a base material, and includes a holding part 2 for slidably holding the cam followers 44; 13, 14, and the holding part 2 includes: A reciprocating compressor provided with a coating layer (6) mainly composed of tin. Cylinder blocks 30 and 31 having cylinder bores 41 and 42, drive shafts 39 rotatably supported by the cylinder blocks 30 and 31, and rotatably integrally with the drive shafts 39. A mounted cam 40; 48; a piston 43 slidably housed in the cylinder bores 41 and 42; and a cam type slidably disposed between the piston 43 and the cam 40; 48. In the reciprocating compressor having an eastern portion (7; 13, 14), the piston 43 reciprocates through the cam followers (7; 13, 14) in accordance with the rotation of the cam (40; 48), The cam followers 7, 13 and 14 are formed of a ferrous metal as a mother material, and slide with the first slide 8 and the cams 40 and 48 slidably held by the piston 43. A reciprocating compressor having a second slide section (10), wherein at least one of the first slide section (8) and the second slide section (10) is provided with a coating layer (11) mainly composed of tin. The reciprocating compressor according to claim 1, wherein the piston (1) has an outer circumferential surface that slides with the inner circumferential surfaces of the cylinder bores (41, 42), and the coating layer (6) is also provided on the outer circumferential surface of the piston (1). . The cam (40; 48) is provided with a slide portion for sliding with the cam followers (44; 13, 14), and the slide portion is provided with a coating layer (15) mainly composed of tin. Reciprocating compressor. 3. The cam 40 (48) according to claim 2, wherein the cam (40; 48) has a slide portion for sliding with the second slide portion (10) of the cam followers (7; 13, 14), the slide portion having a coating layer mainly composed of tin. A reciprocating compressor (15) is provided. The reciprocating compressor according to claim 1, wherein said coating layer (6) contains at least one metal selected from copper, nickel, zinc, lead, and indium. The reciprocating compressor according to claim 2, wherein the coating layer (11) contains at least one metal selected from copper, nickel, zinc, lead, and indium. 2. The cam follower according to claim 1, wherein the cam follower is a shoe (44) having a spherical surface (47), and the holding portion of the piston (1) is a recess (2) for slidably holding the spherical surface (47) of the shoe (44). Reciprocating compressor. 3. The cam follower according to claim 2, wherein the cam follower is a shoe (7) having a substantially hemispherical shape, and the shoe (7) has a spherical surface (8) constituting the first slide part, and the piston (43) is a shoe ( A reciprocating compressor having a concave portion 46 slidably holding the spherical surface 8 of 7). The reciprocating compressor according to claim 1, wherein said coating layer (6) contains one type of solid lubricant selected from fluorine resin powder, molybdenum disulfide powder, carbon powder, and boron nitride powder. The reciprocating compressor according to claim 2, wherein said coating layer (11) contains one type of solid lubricant selected from fluorine resin powder, molybdenum disulfide powder, carbon powder, and boron nitride powder.