JP2001342956A - Method of plating piston for compressor, and piston manufactured therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plating method capable of preventing a leakage of the plating liquid in a following process by restricting the intrusion of the plating liquid inside of a piston hollow part when plating the piston, and to provide a piston manufactured by using this method. SOLUTION: A shoe receiver part 23 of a piston 1 having an opening part 27 communicated with a hollow inside part 26 of a head part 2 in a connection part 22 is formed with a plating layer mainly composed of tin. The piston 1 is supported by a conveyor 31 in the condition that an engagement part 20 is directed downward, and dipped in the plating liquid 30. Since the opening part 27 is directed downward, intrusion of the plating liquid 30 into the hollow inside part 26 is prevented by the air pressure of the hollow inside part 26. Even in the piston 1 having the opening part 27 communicated with the hollow inside part 26, intrusion of the plating liquid 26 into the hollow inside part 26 can be prevented by dipping the piston 1 in the plating liquid 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for plating a piston for a compressor applied to, for example, a vehicle air conditioner and a piston manufactured by using the method.

[0002]

2. Description of the Related Art As a compressor used in an air conditioning system, there is a piston type compressor. Generally, a piston type compressor has a drive shaft rotatably supported by a housing. The swash plate as a cam plate is connected to the drive shaft so as to be integrally rotatable in the housing. The cylinder bore is formed in a cylinder block constituting a part of the housing, and a piston is housed in the cylinder bore. The piston is connected to the swash plate via a shoe. Then, the rotational motion of the swash plate accompanying the rotation of the drive shaft is converted into a reciprocating linear motion of the piston, and an action such as compression of the refrigerant gas is performed.

[0003] Unlike a piston or a swash plate made of an aluminum alloy, a shoe for connecting the piston and the swash plate is made of an iron-based metal from the viewpoint of preventing seizure due to the "togane" phenomenon. Have been.

Therefore, when the discharge capacity is to be increased, increasing the size of the shoe together with the expansion of the compression chamber and the piston immediately leads to an increase in the weight of the entire compressor.
Therefore, when only the piston and the swash plate are enlarged in order to increase the discharge capacity without changing the size of the shoe itself, the load acting on the piston from the swash plate via the shoe increases with the increase in the discharge capacity. growing. Therefore, the frictional force applied between the shoe and the piston becomes considerable, causing poor sliding between the shoe and the piston. The poor sliding reduces the ability to transmit the load between the shoe and the piston, so that a large load acts on the shoe from the swash plate, and the frictional resistance between the shoe and the swash plate significantly increases.

[0005] Further, for the purpose of lubricating each mechanism, the refrigerant gas is led to a crank chamber provided with a swash plate. However, the refrigerant gas currently used is R134a (CF ₃ C) which does not contain chlorine in the molecule due to the problem of depletion of the ozone layer.
Since H ₂ F) is used, and chlorine acting as an extreme pressure agent is not present in the molecule, the lubricating oil remaining on the surface of the swash plate is caused to flow by the purification action of the refrigerant gas. For this reason, the space between the shoe and the swash plate is not lubricated, or the lubricating oil is extremely small.

Therefore, as described above, in order to improve the poor sliding between the shoe and the piston and the lubrication between the shoe and the swash plate or the state where the lubricating oil is extremely small, at least to the shoe receiving portion which is in sliding contact with the shoe. In order to perform plating, it has been proposed to form a plating mainly composed of tin on the entire piston to reduce the above-described sliding resistance and improve seizure resistance, which is disclosed in Japanese Patent Application Laid-Open No. Hei 8-247046. ing.

In recent years, a "hollow piston" has been put to practical use as a technique for reducing the weight of a piston. The hollow piston forms a hollow interior by joining two members, and various shapes have been proposed. Some of the pistons have an opening at the head of the piston for communicating the outside of the piston and the inside of the hollow. For example, there is a piston described in JP-A-11-107912.

The structure of a hollow piston having an opening will be described. The piston includes a head housed in a cylinder bore formed in a housing of the compressor, and an engaging portion connected via a shoe to an outer peripheral portion of a swash plate attached to a drive shaft of the compressor, a connecting portion. Are connected by The connecting portion forms an end surface of the head on the engaging portion side. The head includes a cylindrical portion having a bottomed cylindrical shape in which the suction and discharge valve forming body side of the cylinder bore is a lid side, and a lid portion for closing the hollow interior of the cylindrical portion. The engaging portion has a pair of front and rear concave spherical surfaces, and a shoe receiving portion is formed. An opening for communicating the hollow interior with the outside is provided at the connection portion or at the periphery of the head.

The pair of shoes hold the front and rear surfaces of the outer peripheral portion of the swash plate and are accommodated in the engaging portions, and are spherically received by the corresponding shoe receiving portions.

[0010]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. Hei 8-2
When the plating method described in Japanese Patent No. 47026 is applied to a piston having an opening communicating with the hollow interior, the following problems exist. (1) The piston is cleaned after being taken out of the plating solution. However, in the case of a hollow piston having an opening, the piston is immersed without considering the position of the opening, so that the plating solution does not enter the hollow interior. There was a fear that it could not be completely washed off and remained in the hollow interior. This plating solution leaks during the processing and assembly in a later step and interferes with the operation, causes foreign matter to adhere to the piston, and stains the working member. Therefore, careful cleaning was required. (2) For a piston provided with an opening only at the connecting portion between the head and the engaging portion, when the entire piston is immersed in the plating solution without fixing the inclination angle, the plating solution is opened. It penetrated into the hollow interior through the part. Therefore, plating is applied not only to the engagement portion of the piston but also to the inside of the hollow which is a non-frictional portion.
For this reason, there was a problem that the plating solution was wasted. Of course, in the case where the head has an opening in the periphery, the hollow enters the inside of the hollow through the opening regardless of the inclination angle.

As described above, the piston of the type in which the hollow interior communicates with the outside at the opening is immersed in the plating solution without considering the position of the opening of the piston.
They tended to hinder the subsequent processes, increased costs, and affected the unit cost of the piston.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems existing in the prior art described above, and has as its object to provide a compressor for plating at low cost without any problems in a later step. An object of the present invention is to provide a piston plating method and a piston manufactured using the method.

[0013]

In order to achieve the above object, according to the first aspect of the present invention, a head is slidably received in a cylinder bore formed in a housing of a compressor and has a hollow interior inside. And a coupling portion connected to a cam plate attached to a drive shaft of the compressor and having a shoe receiving portion. The head has an end face on the coupling portion side communicating with the hollow interior. In a method for plating a piston of a compressor having an opening to be formed, at least a shoe receiving portion of the piston has a plating solution in a state in which a head is above an engagement portion and a center axis of the piston is substantially in a vertical direction. The essence was to immerse in the water.

According to the present invention, plating can be applied to at least the shoe receiving portion, which is required to be plated, in a piston having an opening communicating with the hollow interior at the end face on the engaging portion side. Further, since the opening is substantially vertically downward, the plating solution does not enter the hollow interior from the opening, so that there is no inconvenience caused by plating solution leakage in a later step. Further, since no plating is applied to the inside of the hollow, the consumption of the plating solution is reduced.

According to the second aspect of the present invention, the head is slidably received in the cylinder bore formed in the housing of the compressor and has an opening communicating with the hollow interior, and is attached to the drive shaft of the compressor. A plating method for a piston of a compressor having an engaging portion having a shoe receiving portion and being connected to a cam plate, wherein the head of the piston is directed upward,
The gist of the present invention is to immerse only a portion including the shoe receiving portion in the plating solution with the engaging portion facing downward.

According to the present invention, in a piston having an opening in its head communicating with the hollow interior, plating can be applied to at least a shoe receiving portion which requires plating, and plating liquid is introduced from the opening into the hollow interior. Since there is no intrusion, there is no inconvenience caused by leakage of the plating solution in a later step. Since only a part of the piston including the shoe receiving portion is plated, consumption of the plating solution is reduced.

According to a third aspect of the present invention, the gist of the invention is that the piston of the compressor is plated using the piston plating method of the first or second aspect.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention embodied in the process of manufacturing a single-headed piston of a swash plate type compressor applied to a vehicle air conditioner will be described below with reference to FIGS. . In addition, about 2nd Embodiment, FIG. 4 is referred and the same code | symbol is attached | subjected to 1st Embodiment and the description is abbreviate | omitted.

(First Embodiment) First, the configuration of a single-head piston type variable displacement swash plate type compressor will be described. As shown in FIG. 1, a cylinder block 3 which forms a part of a housing and has a cylinder bore 2 is arranged at the center,
A front housing 5 is formed at a front end of the cylinder block 3 so as to form a crank chamber 4 therein, and a rear housing 7 is formed at a rear end of the cylinder block 3 via a valve body 6.
Are fixedly connected to each other. The rear housing 7 is provided with a suction chamber 8 and a discharge chamber 9 that communicate with the cylinder bore 2.

The drive shaft 10 is inserted and supported at the center of the cylinder block 3 and the front housing 5. The drive shaft 10 has a swash plate 11 as a cam plate rotatably housed in the crank chamber 4. It is mounted swingably. The swash plate 11 is connected to the piston 1 via a pair of shoes 12 housed in an engagement portion 20 of the piston 1.

The cylinder block 3 is provided with a communication hole 13 for communicating the crank chamber 4 and the suction chamber 8, and a bellows valve element 14 for opening and closing the communication hole 13 in accordance with the suction pressure is provided in the communication hole 13. It is arranged.

In such a compressor, when the swash plate 11 rotates with the rotation of the drive shaft 10, the piston 1 reciprocates in the cylinder bore 2. As a result, the refrigerant gas sucked into the cylinder bore 2 from the suction chamber 8 is compressed and discharged to the discharge chamber 9. The discharge capacity is determined by the bellows valve element 14 opening and closing the communication hole 13 based on the suction pressure.
It is controlled by adjusting the internal pressure.

That is, when the suction pressure is higher than the set pressure of the bellows valve body 14, the communication hole 13 is opened,
The pressure in the crank chamber 4 is reduced, the stroke of the piston 1 and the inclination angle of the swash plate 11 are increased, and the discharge capacity is increased. Conversely, when the suction pressure is lower than the set pressure of the bellows valve element 14, the communication hole 13 is closed and the pressure in the crank chamber 4 increases, and the stroke of the piston 1 and the inclination angle of the swash plate 11 decrease. Thus, the compression capacity becomes smaller.

Next, the configuration of the piston 1 used in the above-described compressor will be described with reference to FIG.

The piston 1 has a head 21 housed in a cylinder bore 2 formed in a cylinder block 3 of the compressor.
And provided integrally with the head 21 via the connecting portion 22,
An engagement portion 20 disposed outside the cylinder bore 2. The head 21 has a cylindrical portion 24 having a bottomed cylindrical shape that opens on the opposite side to the engaging portion 20, a lid portion 25 that is separate from the cylindrical portion 24, and closes the opening of the cylindrical portion 24. Consists of The connecting portion 22 forms an end surface of the cylindrical portion 24 on the engaging portion 20 side. The engaging portion 20 has a substantially U shape, and the engaging portion 2
A concave spherical shoe receiving portion 23 is formed on each of the opposed front and rear surfaces of the shoe 0 to receive the shoe 12 in a slidable manner. A hollow inside 26 is formed inside the cylindrical portion 24, and a long hole-shaped opening 27 communicating the hollow inside 26 and the outside is formed around the shoe receiving portion 23 in the connecting portion 22. .

An annular groove 28 is formed on the outer peripheral surface of the tip of the cylindrical portion 24.
Are formed. The annular groove 28 rakes up the lubricating oil contained in the refrigerant gas attached to the inner peripheral surface of the cylinder bore 2 by the reciprocating motion of the piston 1. Further, a vertical groove 29 is formed on the outer peripheral surface of the cylindrical portion 24 from near the annular groove 28 toward the engagement portion 20. The vertical groove 29 guides the lubricating oil collected by the annular groove 28 to the crank chamber 4. The lubricating oil is supplied to each sliding portion arranged in the crank chamber 4 by the annular groove 28 and the vertical groove 29.

The piston 1 is made of aluminum or an aluminum alloy as a base material. As the aluminum alloy, for example, an Al-Si alloy or an Al-Si-Cu alloy can be used. As the base material, a material containing hard particles in a matrix is preferably used. In the present embodiment, an azil alloy containing 12% by weight of silicon is used as a base material.

Other base materials containing hard particles include Al-Mn intermetallic compounds, Al-Si-Mn intermetallic compounds, Al-Fe-Mn intermetallic compounds, Al-Cr intermetallic compounds, and the like. Conceivable. In addition, as a base treatment performed on the surface of the base material of the piston 1, it is preferable to perform an alumite treatment, a manganese phosphate treatment, a zinc phosphate treatment, and a zinc plating treatment, and then form a plating layer described later. This is because durability can be further improved.

Next, a method for forming a plating layer on the engaging portion 20 including the shoe receiving portion 23 of the piston 1 will be described. FIG. 3 schematically shows a step of immersing the piston 1 in the plating solution 30. A plating solution 30 containing 6% by weight of potassium stannate and 0.012% by weight of copper gluconate was maintained at 60 to 80 ° C.
The supported piston 1 is immersed so that 0 is directed downward. At this time, the entire piston 1 is immersed so that the axis S is directed substantially in the vertical direction. And even if the opening 27 is formed in the connecting portion 22, the air in the hollow interior 26 cannot escape, so that the plating solution 30 does not enter the hollow interior 26. The engaging portion 20 of the piston 1 is held in the plating solution 30 for about 3 minutes, and after performing electroless plating, is taken out and the plating solution 30 is removed in the cleaning step.

Through these series of steps, tin and copper are eutectoidally plated on the engaging portion 20 including the shoe receiving portion 23 which is in sliding contact with the shoe 12 without infiltrating the plating solution 30 into the hollow interior 26. Is formed. The outer peripheral surface of the cylindrical portion 24 and the lid portion 25 can prevent the formation of a plating layer by forming a coating layer for improving abrasion resistance in the previous process. The thickness of the plating layer is 1.2 μm, and the composition is 3% by weight of copper with respect to 97% by weight of tin.

As described above, the plating layer mainly composed of tin having self-lubricating properties is provided on the shoe receiving portion 2 as a sliding contact portion.
3 is formed on the engaging portion 20 including the first and second engaging portions 3. The sliding resistance is reduced by bringing the shoe receiving portion 23 of the piston 1 into contact with the curved surface of the shoe 12 with the plating layer. That is, when incorporated in the compressor, the shoe 12 driven by the swash plate 11 relatively rotates within the engagement portion 20 of the piston 1 with a small load, so that the sliding resistance between the swash plate 11 and the shoe 12 is reduced. Reduced.

The "substantially vertical direction" is not strictly limited to the vertical direction. That is, the opening 27
The piston 1 at an angle sufficient to prevent the plating solution 30 from entering the hollow interior 26 through the conveyor 3.
You only need to support 1

In the configuration of the plating layer, the coexistence ratio of tin and another metal can be variously selected by experiments depending on the desired performance. For example, when copper is allowed to coexist, the content of copper in the plating layer is preferably from 0.1% by weight to 50% by weight. If the amount of copper is less than 0.1% by weight, the effect of coexistence is poor and the wear resistance is not improved. If the amount is more than 50% by weight, the effect of tin decreases and the frictional resistance between the shoe receiving portion 23 and the shoe 12 is reduced. Undesirably increases. copper,
At least one kind of metal selected from nickel, zinc, lead and indium is particularly preferably 0.8 to 1.2% by weight in the plating layer.

It is also preferable that a solid lubricant such as a fluororesin powder, a molybdenum disulfide powder, a carbon powder, a boron nitride powder and the like coexist in the plating layer. By doing so, the friction resistance can be further reduced.

The thickness of the plating layer is preferably about 1 to 5 μm. If the thickness is smaller than this, the decrease in the coefficient of friction is small, and if the thickness is too large, there may be a problem in strength such as peeling.

The present embodiment having the above configuration has the following effects.

(1) When the piston 1 is immersed in the plating solution 30, the piston 1 is supported on the conveyor 31 with the opening 27 facing downward while the axis S is oriented in the vertical direction. Therefore, the plating solution 30 does not enter the hollow interior 26 due to the air pressure in the hollow interior 26. For this reason, it is not necessary to pay close attention to the immersion depth of the piston, and the subsequent washing step of the plating solution 30 is simplified, and there is no leakage of the plating solution 30 in a later step.

(2) Since plating is not applied to the hollow interior 26, consumption of the plating solution 30 can be reduced.

(3) In the shoe receiving portion 23, the sliding resistance of the piston 1 plated in this embodiment with the shoe 12 can be reduced.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

In the second embodiment, an opening 27 communicating between the hollow interior 26 and the outside is formed on the peripheral surface of the head 21 of the piston 1.

Next, a method for forming a plating layer on the engaging portion 20 including the shoe receiving portion 23 of the piston 1 will be described. FIG. 4 shows that the engagement portion 20 of the piston 1 is
2 schematically shows a step of immersion in the substrate. The piston 1 supported on the conveyor 31 with the engagement portion 20 facing downward is immersed in the plating solution 30. At this time, the engaging portion 2 of the piston 1
0 soaked in the plating solution 30
Relative to the plating solution 30, or the plating solution 30
Is adjusted. In this way, a plating layer mainly composed of tin having self-lubricating properties is formed on at least the shoe receiving portion 23 as a sliding contact portion.

In the present embodiment, the piston 1 may be supported on the conveyor 31 at an angle such that the shoe receiving portion 23, which is an essential plating portion, is immersed to the minimum necessary. As the inclination angle, the inclination of the axis S of the piston 1 with respect to the vertical direction is 60 degrees or less, and preferably 45 degrees or less.

The present embodiment having the above configuration has the following effects in addition to the effects (2) and (3) of the first embodiment described above.

(1) When immersed in the plating solution 30, the piston 1 is supported on the conveyor 31 with the engaging portion 20 facing downward. Therefore, only the engaging portion 20 including the shoe receiving portion 23 can be immersed in the plating solution 30, and the plating solution 30 does not enter the hollow interior 26 from the opening 27.
Therefore, the subsequent washing step of the plating solution 30 is simplified, and there is no leakage of the plating solution 30 in the subsequent steps.

(2) Since the engaging portion 20 is supported on the conveyor 31 with the downward direction, plating can be applied to a minimum necessary portion without troublesome masking. Therefore, consumption of the plating solution 30 can be reduced.

(3) The plated piston 1 in the present embodiment does not have a plating layer formed on the head 21, so that the piston 1 needs to be appropriately and appropriately abraded with the cylinder bore 2 in a later step. Processing can be performed.

The present invention can be carried out in the following manner without departing from the spirit of the present invention.

In the piston 1 having the opening 27 in the periphery of the head 21, the connecting portion 2
2 and a part of the head 21 is immersed in a state where the opening 27 is not immersed in the plating solution 30. Therefore, the consumption of the plating solution 30 can be suppressed, and the labor required for cleaning the hollow interior 26 can be reduced.

[0050]

According to the present invention having the above-described structure, a method for plating a piston for a compressor can be performed at low cost without inconvenience due to leakage of plating solution in a later step and by suppressing consumption of the plating solution. Can be provided. Further, the piston formed thereby can reduce sliding resistance at the sliding portion.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a single-head piston type variable displacement compressor.

FIG. 2 is a partially broken side view of a hollow piston.

FIG. 3 is a schematic view of a step of immersing a hollow piston in a plating solution.

FIG. 4 is a schematic view of a step of immersing a hollow piston in a plating solution according to a second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... piston, 2 ... cylinder bore, 3 ... cylinder block which comprises a part of housing, 5 ... front housing, 7 ... rear housing, 10 ... drive shaft, 11 ... swash plate as a cam plate, 20 ... engagement part, 21 ... head, 23
... Shoe receiving part, 26 ... Hollow inside, 27 ... Opening part, 30 ...
Plating solution, S ... axis.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H003 AA03 AB07 AC03 AD01 CB00 CE04 CF00 3H076 AA06 BB50 CC33 CC34 4K022 AA02 AA31 AA48 BA08 BA10 BA14 BA17 BA21 BA25 BA32 BA34 DA01

Claims (3)

[Claims] 1. A compressor which is slidably received in a cylinder bore formed in a housing of a compressor, and which is connected to a head constituting a hollow interior therein and a cam plate attached to a drive shaft of the compressor. And an engaging part having a shoe receiving part, wherein the head has an opening communicating with the hollow interior at the end face on the engaging part side. A method of plating a piston, wherein at least the shoe receiving portion is immersed in a plating solution in a state in which the portion is above the engagement portion and the center axis of the piston is substantially in a vertical direction. 2. A head, which is slidably received in a cylinder bore formed in a housing of the compressor and has an opening communicating with the hollow interior, and a cam plate attached to a drive shaft of the compressor. A method of plating a piston of a compressor, comprising a coupling and an engaging portion having a shoe receiving portion, comprising: a shoe receiving portion with the head of the piston facing upward and the engaging portion facing downward. A plating method for pistons in which only some parts are immersed in a plating solution. 3. A piston of a compressor plated using the method for plating a piston according to claim 1.