JP2003262186A - Shoe for cam plate type compressor and forming method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shoe for a cam plate type compressor having excellent sliding characteristic and high dimensional accuracy. <P>SOLUTION: The shoe 76 is provided with a stage difference in a peripheral edge part of a cam plate side engagement surface part 152 thereof. In detail of shape of the shoe, the cam plate side engagement surface part 152 has a counter-cam-plate sliding surface part 154, a peripheral edge surface 156 formed backward with a stage difference from the counter-cam-plate sliding surface 154, and a connection surface 158 for connecting both the surfaces at the stage difference part. Suction of the lubricating oil to a sliding surface of the cam plate, the counter-cam-plate sliding surface 154 and between both the surfaces is secured by existence of the connection surface 158 in the peripheral end of the counter-cam-plate sliding surface 154, and while intrusion of a foreign material between both the surfaces is restricted. In the case of forging, since shape of the peripheral part of the shoe is hard to resist plastic flow of the raw material, forming load can be reduced, and as a result, unevenness of forming dimension due to unevenness of quantity of the raw material can be restricted. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shoe arranged between a swash plate and a piston in a swash plate compressor, and a method for forming the shoe.

[0002]

2. Description of the Related Art A swash plate compressor converts the rotation of a swash plate into a reciprocating motion of a piston to compress a gas, and a swash plate that rotates at a high speed and a piston that reciprocates at a high speed.
A shoe as a sliding member is provided to ensure smooth operation of both. Since the swash plate is rotated at a high speed, the sliding property between the swash plate and the shoe is required to be particularly good. The shoe has a spherical crown shape, that is, the outer surface has a piston-side engagement surface portion that is generally convex and engages with the piston, and a swash plate-side engagement surface portion that is generally flat and engages with the swash plate. Those having a shape that is generally divided into are often used. In this spherical crown shoe, it is desired that the sliding characteristics between the swash plate side sliding contact surface portion and the swash plate engaging with the swash plate side surface are particularly good. Specifically, for example, it is required that the supplied lubricating oil be sufficiently drawn in between the sliding contact surfaces of both the shoe and the swash plate. It is required not to be drawn between the sliding contact surfaces so as not to damage the contact surfaces.

In order to meet the above-mentioned requirements that seem to be antinomy, the applicant of the present invention has filed an unpublished patent application (Japanese Patent Application No. 2001-139539) with an engagement surface portion on the swash plate side and an engagement on the piston side. There is disclosed a spherical crown shoe formed by providing a side surface portion connecting the surface portion and the side surface portion, and forming the side surface portion at an angle of, for example, 45 ° with respect to the surface of the swash plate. The shoe has good sliding properties.

Like the conventional shoe, the shoe disclosed above is formed by forging. The forging of the shoe is performed by first forming a die surface that forms the piston-side engaging surface portion.
Using a mold pair including a mold and a second mold having a swash plate side engaging surface portion and a mold surface for molding a side surface portion, and placing the material piece at the center of the mold pair, This is done by closing the mold pair. The material plastically flows in the cavity of the mold toward the outer peripheral direction, reaches the part that forms the side surface of the mold surface, and plastically flows along that part from that state, firmly on the mold surface. By being pressed, the shoe is shaped.

[0005]

Problems to be Solved by the Invention, Means for Solving the Problems, and Effects The shoes are also required to have good dimensional accuracy. In particular, the dimension in the height direction (the surface distance between the swash plate side engagement surface portion and the piston side engagement surface portion) is high due to the mechanism of the swash plate type compressor, for example, the allowable width for variation in clearance is small. Precision is required. On the other hand, with respect to the material piece used for forming and forging, there is a demand to keep the manufacturing cost as low as possible, and there is a circumstance that variation in the material amount must be allowed to some extent.

Against this background, the present inventor investigated the behavior of the forging material in the forging of the shoe in order to improve the dimensional accuracy of the shoe. In the mold pair, in the outer peripheral portion in the cavity, a portion where the side surface portion and the piston side engagement surface portion are connected is formed, but that portion is a space for absorbing the variation in the material amount. Function as. However, as described above, since the side surface portion has a shape that makes a relatively large angle with respect to the surface of the swash plate, the mold surface that forms the side surface portion becomes a large resistance to the plastic flow of the material, and as a result, For example, it has been found that when the amount of material is larger than the regular amount, the ratio of increase in reaction force from the material to the mold, increase in springback amount, and the like also increases. That is, when the shoe is manufactured by forging with a large resistance, the dimension of the molded shoe also varies greatly due to the variation in the amount of material.

[0007] Therefore, the present invention has been made to solve the problems of obtaining a shoe for a swash plate type compressor having good sliding characteristics and high dimensional accuracy. A shoe for a swash plate type compressor, a molding method thereof, and the like can be obtained. Similar to the claims, each mode is divided into paragraphs, each paragraph is numbered, and the numbers of other paragraphs are referred to as necessary. This is merely for facilitating the understanding of the present invention, and the technical features and combinations thereof described in the present specification should not be construed as being limited to those described in the following respective sections. . Moreover, when a plurality of items are described in one section, it is not always necessary to adopt the plurality of items together. It is also possible to select and use only some items.

In each of the following items, item (1) corresponds to item 1, item (2) and item (3) are combined and item (4) is included. 3, claim (6) corresponds to claim 4, claim (13) corresponds to claim 5, and claim (21) corresponds to claim 6.

(1) In a swash plate type compressor, the outer surface is disposed between the swash plate and the piston, and the outer surface thereof forms a generally convex spherical surface and a piston side engaging surface portion which engages with the piston. A swash plate side engagement surface part that engages with a swash plate, and is a spherical crown-shaped shoe, wherein the swash plate side engagement surface part is
The center portion of the swash plate side engaging surface portion is formed, and a substantially flat anti-swash plate sliding contact surface that slidably contacts the surface of the swash plate and a peripheral portion of the swash plate side engaging surface portion are formed. Having a stepped back from the plate sliding contact surface and having a peripheral surface connected to the piston side engagement surface portion at the outer peripheral edge, and an annular connecting surface connecting the peripheral surface and the swash plate sliding contact surface. Shoe for swash plate type compressor.

The shoes described in this section are roughly:
In a general ball-crown shoe, a step recessed with respect to the central portion is provided at the outer peripheral edge portion of the swash plate side engaging surface portion. The outer peripheral edge portion of the sliding contact surface of the swash plate ensures that the lubricating oil is drawn between the sliding contact surface of the swash plate and the sliding contact surface of the swash plate, while preventing the drawing of large foreign matter between the surfaces. It is desired to play a role of restraining, and the above-mentioned connecting surface existing at the step, which is that portion, is an important existence. Although the specific shape of the connecting surface is not limited, it is possible to have a function of drawing in the lubricating oil and a function of repelling the foreign matter by adopting the configuration described later, for example. In the shoe described in the unpublished application, the side surface portion formed as a tapered surface fulfills its function, but the presence of the side surface portion, in the case of forging the shoe,
This causes a great resistance when the forged material plastically flows. On the other hand, in the shoe described in this section that does not have such a side surface portion, since there is no portion that causes a large resistance in forging, forging can be performed with high dimensional accuracy. That is, the sliding characteristics are secured, and a shoe with higher dimensional accuracy can be obtained. Also, when a shoe with insufficient dimensional accuracy is molded, for example, it takes a lot of time to adjust the dimension by polishing performed after molding,
The cost of manufacturing the shoe is significantly higher. In that respect, the shoe described in this section can be said to be a shoe that can be manufactured at low cost.

To explain the dimensional accuracy in more detail,
When performing forging, the material piece is set in the center of the mold and the material is plastically flowed in the outer peripheral direction. As described above, in the forging with high resistance, it is necessary to increase the molding load, and the reaction force from the material to the mold becomes large. When the force applied to the material and the mold is large, large elastic deformation occurs in both. For example, when a large elastic deformation occurs in the mold, the cavity shape is also deformed, and when a large elastic deformation occurs in the material, the springback amount after molding becomes large. If there is a situation where the amount of material must be allowed to vary to some extent, even if a space for absorbing the variation is provided in the cavity, that variation is caused when performing forging with large resistance. The variation in the molding dimension becomes large. With the shoes described in this section,
In forging, since the material can plastically flow over the step or cover the step, it is possible to perform the forming with a relatively small forming load without causing a large resistance. As a result, a shoe having high dimensional accuracy, particularly dimensional accuracy in the height direction of the shoe, can be obtained. That is, in the shoe described in this section, the outer peripheral edge portion of the shoe surrounded by the peripheral edge surface and the piston-side engaging surface portion can function as a portion that effectively absorbs the variation in the material amount. . In summary, the shoe described in this section achieves both the sliding characteristic and the dimensional accuracy due to the characteristics of the shape. By the way, if the height of the shoe is not accurate, for example, if the distance between the sliding contact surface of the shoe and piston is too large, it becomes easier for foreign matter to enter, and if the distance between the sliding contact surfaces becomes too small. The friction between the two becomes excessive, and the sliding characteristics deteriorate in any case.

It should be noted that the spherical crown shoe is generally hemispherical because it has the above-mentioned shape, in other words, the side that engages with the piston has a substantially spherical surface and the side that engages with the swash plate has a substantially flat surface. It is called Shu. However, the shape is not necessarily strictly spherical or flat, and is often slightly deviated from the spherical or flat surface for the purpose of improving sliding performance. For example, the sliding contact surface against the swash plate may be formed as a medium convex shape (for example, a convex spherical surface having an extremely large radius of curvature) in which the center bulges about 0.5 to 10 μm as compared with the peripheral edge. The spherical crown shoe referred to in the specification also includes a shoe having a shape accompanied by such deformation. The shoe described in this section can be used for both variable displacement type and fixed displacement type swash plate type compressors, but those for variable displacement type compressors are smaller than hemispheres, and are used for fixed displacement type compressors. Objects are usually larger than hemispheres. In a variable displacement compressor, it is necessary that both spherical parts of a pair of shoes arranged on both sides of the swash plate be located on a substantially spherical surface, and therefore, it is smaller than the hemisphere by half the thickness of the swash plate. In addition, in the fixed displacement type compressor, since there is no such limitation as described above, it is slightly larger than the hemisphere for the reason that the area of the sliding contact surface does not decrease even if the flat part of the shoe wears. It is often done. Therefore, in this specification, both types of shoes are generically referred to as spherical crown shoes.

(2) The swash plate compressor shoe according to item (1), wherein the step between the sliding contact surface against the swash plate and the peripheral surface is 0.02 mm or more. (3) The step between the sliding contact surface against the swash plate and the peripheral surface is 0.5.
The shoe for a swash plate compressor according to any one of the items (1) and (2), which has a size of not more than mm.

The "step between the sliding contact surface against the swash plate and the peripheral surface" means
It means the distance between the extended surface of the sliding contact surface against the swash plate and the end of the peripheral surface connected to the connecting surface. When the sliding contact surface against the swash plate is a flat surface and the peripheral edge surface and the sliding contact surface against the swash plate are parallel to each other, the distance between the two surfaces is obtained. When the sliding contact surface against the swash plate has the above-mentioned convex shape, the "extended surface of the sliding contact surface against the swash plate" is in contact with the sliding contact surface against the swash plate at right angles to the shoe center line. Treat as a plane. In other words, in that case, when the shoe is slid on the swash plate in a straight state (the center line of the shoe is at a right angle to the slidable surface of the swash plate), the slidable contact surface of the swash plate and the peripheral surface Corresponds to the distance from the end of the.

The amount of the step between the sliding contact surface and the peripheral surface of the swash plate influences the characteristics of the shoe. For example, if the step is too small, it becomes difficult for the lubricating oil to be drawn between the sliding contact surface of the swash plate and the sliding contact surface of the shoe against the swash plate. Considering this, it is desirable that the step difference is 0.02 mm or more. Further, the smaller the step, the easier it is for even a small foreign matter to be caught between the peripheral surface and the swash plate surface. Further, as the step becomes smaller, the shape of the connecting surface is restricted, and there is a possibility that the connecting surface having an appropriate shape that can exert the lubricating oil drawing function and the foreign matter repelling function cannot be formed. In view of these, it is desirable that the step be 0.05 mm or more. From the standpoint that even larger foreign matter is not caught, it is more preferable that the thickness be 0.1 mm or more,
More preferably, it is 5 mm or more. On the contrary, when the step is large, the resistance to the plastic flow of the material in the forging described above becomes large. In consideration of that point, the size of the step is preferably 0.5 mm or less. In terms of reducing the resistance, 0.3
It is more preferable that the thickness is less than or equal to mm, and further preferable that the length is less than or equal to 0.25 mm.

(4) The swash plate compressor shoe according to any one of the items (1) to (3), wherein the peripheral surface and the sliding contact surface against the swash plate are substantially parallel to each other. (5) The peripheral surface is inclined with respect to the sliding contact surface against the swash plate, and the angle formed by the peripheral surface and the extension surface of the sliding contact surface against the swash plate is 10 ° or less. A shoe for a swash plate compressor according to any one of (1) to (3).

From the viewpoint of reducing the resistance of the plastic flow of the material in the forging, the peripheral surface is substantially parallel to the sliding contact surface against the swash plate as in the aspect described in the item (4). Is desirable. Further, even if it is not parallel, as in the aspect described in (5), when it is gently inclined with respect to the sliding contact surface against the swash plate, the resistance becomes relatively small, It can be one aspect of the shoe of the present invention.

(6) The connecting surface has a tapered portion having a truncated cone peripheral surface shape which widens toward the peripheral surface, and a corner R portion connecting the tapered portion and the sliding contact surface against the swash plate ( The shoe for a swash plate type compressor according to any one of items 1) to 5).

As described above, when sliding between the shoe and the swash plate, the lubricating oil is sufficiently drawn between the sliding contact surface of the shoe and the sliding contact surface of the swash plate, and is a harmful foreign substance. If you don't meet the requirement that
Good sliding characteristics cannot be obtained. Taking the swash plate type compressor that constitutes the air conditioner as an example, the drawing of the lubricating oil and the repulsion of the foreign matter will be described in detail. Lubricating oil is mixed in the refrigerant gas, and the lubricating oil forms an oil film between the two sliding contact surfaces, so that the sliding characteristics between the shoe and the swash plate are maintained well. Therefore, if the lubricating oil is not sufficiently drawn between the two sliding contact surfaces, the sliding characteristics deteriorate. In addition, various foreign matters such as shavings generated by friction in various places during operation, minute burrs generated and remaining in the manufacturing process of each component, and dust introduced from a connected refrigerant pipe may exist. These foreign substances should be well controlled, but it is difficult to eliminate them completely,
There is a possibility that foreign matter may be drawn and intervene between the sliding contact surfaces of both the swash plate and the shoe. When foreign matter is present between both sliding contact surfaces, the foreign matter damages both sliding contact surfaces and deteriorates the sliding characteristics. In order to satisfy both the pull-in characteristic of the lubricating oil and the repellent characteristic of the foreign matter, the shape of the peripheral portion of the sliding contact surface of the shoe which is in sliding contact with the swash plate is important. In the shoe of the present invention, specifically, these requirements can be satisfied by adjusting the shape of the connecting surface existing adjacent to the peripheral edge of the sliding contact surface of the swash plate. The aspect described in this section is one aspect thereof. By adjusting the shapes of the taper portion and the corner R portion, the lubricating oil pull-in characteristic and the foreign matter repelling characteristic can be arbitrarily adjusted, and a shoe having excellent sliding characteristics can be obtained.

Further, in the case where the tapered portion and the sliding contact surface against the swash plate are directly adjacent to each other, that is, when the corners on both sides are so-called pin angles, the swash plate surface is rubbed by the corner.
For example, a lubricating coating containing a solid lubricant may be formed on the sliding contact surface of the swash plate in order to further ensure lubricity, and the lubricating coating has relatively low strength and hardness. In such a case, the corners at the pin angle of the shoe also act to peel off the lubricating coating. Further, in the case of the pin angle, it is considered that the lubricating oil is also repelled, and it becomes difficult to take in sufficient lubricating oil between the respective sliding contact surfaces of the shoe and the swash plate. Furthermore, the shoe is often barrel-polished after molding to smooth the surface, and a shoe having a corner with a pin angle is likely to collide with each other in the barrel-polishing and make a dent. Furthermore, there is also a shoe with a metal plating film formed on the surface, and if such shoe has a corner with a pin angle, barrel plating may wear the metal plating film on the corner and expose the base material. There is also a nature. All of these phenomena are disadvantages due to the corners having pin angles. In the shoe described in this item, the tapered portion and the sliding contact surface on the swash plate side are adjacent to each other with the corner R portion interposed therebetween, in other words, the corner is rounded, and the above-mentioned disadvantages are alleviated. It will be a good quality shoe.

The taper portion is defined as having a surface having a truncated cone peripheral surface shape that widens toward the peripheral surface, but since it is provided in a relatively small step portion, its length (shoe height) The distance in the direction) is short. The connecting surface may be configured to have another corner R part that connects the peripheral surface and the taper part, in addition to the corner R part for manufacturing reasons or the like. In that case, for example, a step may be formed. When it is small or when the two corners R are relatively large, the length of the tapered portion is extremely small. In the ultimate state, its length is almost zero. In the aspect described in this section, the tapered portion includes those in the ultimate state. That is,
In that case, the boundary portion between the two corner R portions is regarded as a tapered portion.

(7) The swash plate compressor shoe according to item (6), wherein the angle formed by the tapered portion and the extension surface of the sliding contact surface against the swash plate is 35 ° or more. (8) The swash plate compressor shoe according to item (6) or (7), wherein an angle formed by the tapered portion and the extension surface of the sliding contact surface against the swash plate is 90 ° or less.

The angle of the taper portion (the above-mentioned "angle formed between the taper portion and the extension surface of the sliding contact surface against the swash plate. Unless otherwise specified, hereinafter abbreviated as such.") Is relatively small and appropriate. If the angle is large, the lubricating oil drawing-in characteristic becomes good. However, if the angle of the taper portion is too small, the foreign matter repulsion characteristic deteriorates if the angle is too small. That is, the taper portion easily gets on the foreign matter, and if the shoe moves while riding on the foreign matter, the foreign matter will be drawn between the swash plate side sliding contact surface of the shoe and the swash plate sliding contact surface. is there. On the other hand, 90
If the angle of the taper portion is increased up to a limit of °, the taper surface acts so as to push away the foreign matter. That is,
The foreign matter repulsion characteristic becomes better as the angle of the taper portion increases. When a foreign matter enters between the sliding contact surfaces, the foreign matter not only increases the friction of the sliding contact surface but also damages each sliding contact surface. The scratches generated on each of them further damage each other, which causes deterioration of sliding characteristics. Also, if the taper angle is small, the shoe will ride on the foreign material, and the foreign material will be forced between the narrow sliding contact surfaces, resulting in deep scratches on the shoe and swash plate sliding contact surfaces. Becomes Therefore, deep scratches are likely to be formed, and in that sense, the ability to withstand foreign matter, that is, the foreign matter resistance is inferior, and a shoe with a small taper angle has poor sliding characteristics. On the other hand, even when the angle of the taper portion is large, the step is relatively small, and thus resistance to plastic flow of the material is less likely to occur during forging, which is not a factor that deteriorates the dimensional accuracy of the shoe.

In view of the above, the angle of the tapered portion is 3
The angle is preferably 5 ° or more, and more preferably 40 ° or more in order to obtain higher foreign matter repelling characteristics.
Further, the angle of the tapered portion is preferably 90 ° or less, and is set to 75 ° or less in consideration of the lubricating oil drawing characteristics and the smaller the angle of the tapered portion is, the smaller the resistance in forging is. Desirably, the angle is preferably 60 ° or less, more preferably 50 ° or less.

In the ultimate state where the length of the tapered portion is almost 0 as described above, the two corners R described above are used.
The angle of the boundary of the part, that is, the one tangent line contacting the two corners R in the shoe cross section cut by a plane including the diameter and perpendicular to the sliding contact surface of the swash plate and the extension surface of the sliding contact surface of the swash plate. The angle formed is the angle of the tapered portion. When the sliding contact surface against the swash plate has a convex shape, the "extension surface of the sliding contact surface against the swash plate" is, as described above, orthogonal to the shoe center line and is the sliding contact surface against the swash plate. Treat as a contacting plane. That is, when the shoe is slidably brought into slidable contact with the swash plate, the angle formed by the slidable contact surface of the swash plate and the tapered portion corresponds to the angle of the tapered portion.

(9) The radius of curvature of the corner R portion is 0.0
The shoe for a swash plate compressor according to any one of (6) to (8), which has a size of 5 mm or more. (10) The shoe for a swash plate compressor according to any of (6) to (9), wherein the radius of curvature of the corner R portion is 0.5 mm or less.

By providing the corner R portion, the effect of alleviating the above-mentioned demerits, that is, the effect of drawing the lubricating oil between the sliding contact surfaces, suppressing the dents of the shoe during barrel polishing, and suppressing the wear of the metal plating film is substantially achieved. To get
A corner having a radius of curvature of 0.05 m or more is desirable. In addition, those effects are enhanced when the radius of curvature is large to some extent. Therefore, if the effect is emphasized, the radius of curvature of the corner R portion is more preferably 0.1 mm or more, and further preferably 0.15 mm or more. On the other hand, when the radius of curvature of the corner R portion is large, a relatively small foreign substance comes into contact with the corner R portion instead of the tapered portion. In this case, the characteristic of rejecting the foreign matter depends on the angle between the tangent plane to the corner R portion at the contact point with the foreign matter and the extension surface of the swash plate side sliding contact surface. When a corner R portion comes into contact with a foreign matter to remove the foreign matter, the larger the tangent plane angle, the better the foreign matter elimination property. The smaller the radius of curvature of the corner R, the larger the tangent plane angle when a foreign matter of the same size contacts the corner R portion. That is, the smaller the radius of curvature of the corner R portion, the better the foreign matter repulsion characteristic. Therefore, according to that, the corner R
It is desirable that the radius of curvature of is 0.5 mm or less,
0.4mm or less is more desirable, 0.3mm
The following is more desirable.

(11) Base material is made of aluminum alloy
The shoe for a swash plate compressor according to any one of (1) to (10). (12) The shoe for a swash plate compressor according to any one of items (1) to (10), wherein the base material is a high carbon chromium bearing steel.

The material of the base material of the shoe of the present invention is not limited. It can be formed of various metal materials and the like. Since the shoe whose base material is made of an aluminum alloy is lightweight, it is suitable for a swash plate compressor for which weight reduction is particularly desired, for example, a swash plate compressor used for applications such as a vehicle air conditioner. Becomes The type of aluminum-based alloy is not limited. Aluminum-based alloys that are already commonly used in various fields and various known aluminum-based alloys can be used. More specifically, for example, A4032 (JIS H40
Al--Si alloys having a eutectic composition such as (00) or the like can be used. The Al-Si alloy has a small coefficient of thermal expansion and good wear resistance, and when this alloy is used, it becomes a shoe having good sliding characteristics. Also, for example, A2
017, A2024 (JIS H 4000 etc.) A
An l-Cu-Mg-based alloy can be used. Al-
Since the Cu-Mg-based alloy has high strength, use of this alloy provides a shoe having high strength and excellent durability.
The aluminum alloy is preferably coated with a hard metal plating film on the surface, and the hard metal plating film is preferably an electroless nickel plating film such as Ni-P or Ni-B. The electroless nickel plating film can form a uniform hard metal plating film, and the film has a Vickers hardness Hv at the time of deposition.
It has a high hardness of 500 or more and is excellent in wear resistance and corrosion resistance. It should be noted that aluminum alloy shoes are often forged from a cylindrical material piece, and since the cylindrical material piece has a large variation in the amount of material, in that sense, the present invention can be applied to an aluminum alloy shoe. The advantages of applying are great.

The shoe of the present invention may be made of an iron alloy. Iron-based alloys are inexpensive and have relatively high strength and hardness. Therefore, the shoe described in this section is inexpensive and has excellent wear resistance and durability. The type of iron-based alloy is not limited, but because of its extremely high hardness and excellent abrasion resistance and heat resistance, high carbon chromium bearing steel (specifically SUJ2
(JIS G 4805)) is preferably adopted. In the case of a shoe made of high carbon chrome bearing steel, it is desirable to manufacture it by performing heat treatment such as quenching and tempering and nitriding. The shoe made of high carbon chrome bearing steel is
Compared with aluminum alloy shoes, forging requires a large forming load. The shoe of the present invention can easily achieve plastic flow of the material in forging even when there are variations in the material, so that the effect of reducing the cost of the die can be obtained, and the high carbon chromium bearing steel is obtained. The advantage of applying the present invention to a manufactured shoe is great.

To reiterate, the base material of the shoe of the present invention is not limited to the above aluminum alloy and the above iron alloy. The above description does not prevent the use of other metal material such as magnesium, resin, or the like as the base material of the shoe.

(13) The shoe has a first mold having a mold surface for molding the piston side engaging surface portion and a second mold having a mold surface for molding the swash plate side engaging surface portion. Using a pair of dies, a material piece having an outer diameter smaller than the diameter of the sliding contact surface of the swash plate is set in the center of the pair of dies, and the pair of dies is forged by closing the pair of dies. The shoe for a swash plate compressor according to any one of (1) to (12). (14) Forged from the cylindrical material piece
Shoe for a swash plate compressor according to item (13).

As described above, the shoe of the present invention can easily undergo plastic flow of the material during forging due to its shape characteristics. Therefore, the advantages of the forged shoe are fully exhibited. The shape of the material piece is not particularly limited, and it may be forged from a spherical material piece. In that case, similar to the manufacture of the bearing balls, it is possible to manufacture a material piece with a small amount of material variation by undergoing processing steps such as flushing and grinding. Further, it may be forged from a cylindrical material piece. A cylindrical material piece can be prepared at low cost by cutting a rod, but the amount of material varies greatly. Particularly, in the case of shearing cutting or the like, the cost is cheaper, but the variation in the amount of material becomes larger.
Since the shoe of the present invention has good dimensional accuracy after being forged even if there are variations in the amount of material, the advantage of applying the present invention to a shoe that is forged from a cylindrical material piece. Will be big.

(21) In the swash plate type compressor, the outer surface is disposed between the swash plate and the piston, and the outer surface thereof forms a generally convex surface and the piston side engaging surface portion which engages with the piston, and forms a generally flat surface. The swash plate-side engaging surface portion that engages with the swash plate is roughly divided, and the swash plate-side engaging surface portion constitutes (a) the central portion of the swash plate-side engaging surface portion. A substantially flat anti-swash plate sliding contact surface that makes sliding contact, and (b) constitutes a peripheral portion of the swash plate side engaging surface portion, retracts with a step from the anti-swash plate sliding contact surface,
A method for molding a spherical crown shoe having a peripheral surface connected to the piston side engagement surface portion at the outer peripheral edge, and (c) an annular connecting surface connecting the peripheral surface and the sliding contact surface to the swash plate. A material piece preparing step of preparing a material piece having an outer diameter smaller than an outer diameter of the sliding contact surface against the swash plate; a first die having a die surface for molding the piston side engaging surface portion; A mold pair including a second mold having a mold surface for molding the plate side engaging surface portion is used, the material piece is set in the center of the mold pair, and the mold pair is closed. And a forging step of forging the spherical crown shoe, the method for forming a shoe for a swash plate compressor. (22) The method for forming a shoe for a swash plate compressor according to item (21), wherein the material piece preparing step is to prepare a cylindrical material piece.

The molding method of the present invention is the method of molding a shoe of the present invention, and comprises a pair of molds which are separated from each other in the vicinity of the boundary between the piston side engagement surface portion and the swash plate side engagement surface portion. By using this, the material piece is crushed in the shoe height direction and the material is plastically flowed in the outer peripheral direction for forging. Due to the above-mentioned geometrical characteristics, the plastic flow is smoothly performed, and a large forming load is not required even when there is a variation in the amount of material, and as a result, the formed shoe has dimensional accuracy, especially dimensional accuracy in the height direction. Will be good. Further, as described above, even if there is a variation in the amount of material, the shoe can be manufactured with high dimensional accuracy according to the present molding method. Therefore, if an inexpensive cylindrical material piece is used, an inexpensive shoe can be obtained. it can. In addition,
It is an embodiment in which the shoe and the mold pair to be molded by the molding method of the present invention are limited by the technical features described in the above items (2) to (20). Good.

(31) A swash plate and a piston are provided, and between the swash plate and the piston, the items (1) to (1) are provided.
A swash plate compressor comprising the shoe according to any one of the items 4). The swash plate type compressor of the present invention is a swash plate type compressor provided with the shoe of the present invention, and has a good sliding characteristic.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, as embodiments of the present invention,
A variable capacity type swash plate compressor used for a vehicle air conditioner and a spherical crown-shaped shoe that is a component of the variable capacity type compressor will be taken as an example and described in detail with reference to the drawings. For convenience of explanation, first, the overall configuration of the swash plate compressor will be described, and then the shape of the shoe and the sliding contact state between the shoe and the swash plate will be described, and then the method for manufacturing the shoe will be further described. To do. Note that the present invention is by no means limited to the following embodiments, and in addition to the following embodiments, including the modes described in the above [Problems to be solved by the invention, problem solving means and effects] For example, it can be implemented in a form in which various changes and improvements are made based on the knowledge of those skilled in the art.

<Overall Structure of Swash Plate Compressor> FIG. 1 shows a swash plate compressor according to the present invention. In FIG. 1, reference numeral 10 denotes a cylinder block, and a plurality of cylinder bores 1 extending in the axial direction are provided on one circumference around the central axis of the cylinder block 10.
2 is formed. A single-headed piston 14 (hereinafter abbreviated as piston 14) is provided in each of the cylinder bores 12 so as to reciprocate. A front housing 16 is attached to one axial end surface of the cylinder block 10 (the left end surface in FIG. 1, which is referred to as the front end surface).
A rear housing 18 is attached to the other end surface (which is the right end surface in FIG. 1 and is referred to as a rear end surface) via a valve plate 20. Front housing 16,
The rear housing 18, the cylinder block 10, and the like constitute a housing of the swash plate compressor. The suction chamber 2 is provided between the rear housing 18 and the valve plate 20.
2, the discharge chamber 24 is formed, and the suction port 2
6, via the supply port 28, is connected to a refrigeration circuit (not shown). The valve plate 20 is provided with a suction hole 32, a suction valve 34, a discharge hole 36, a discharge valve 38, and the like.

A rotary shaft 50 is provided in the housing so as to be rotatable about the central axis of the cylinder block 10. The rotary shaft 50 is rotatably supported at its both ends by the front housing 16 and the cylinder block 10 via bearings.
A support hole 56 is formed at the center of the cylinder block 10, and the support hole 56 is supported through the bearing in the support hole 56. An end of the rotary shaft 50 on the front housing 16 side is connected to a vehicle engine as a drive source (not shown) via a clutch device such as an electromagnetic clutch. Therefore, when the rotating shaft 50 is connected to the vehicle engine by the clutch device during operation of the vehicle engine, the rotating shaft 50 is rotated about its own axis.

A swash plate 60 is attached to the rotary shaft 50 so as to be movable in the axial direction and tiltable. Swash plate 60
Has a through hole 61 passing through the center line, and the rotary shaft 50 passes through the through hole 61. The through hole 61 has a gradually increasing inner dimension in the up-down direction in FIG. 1 on the opening side of both ends, and the cross-sectional shape of these both ends is a long hole. A rotary plate 62 is fixed to the rotary shaft 50 and is received by the front housing 16 via a thrust bearing 64. The swash plate 60 has a hinge mechanism 66,
It is allowed to rotate integrally with the rotary shaft 50 and is allowed to tilt with movement in the axial direction. The hinge mechanism 66 includes a support arm 67 fixedly provided on the rotating plate 62 and a swash plate 6.
0 fixedly provided with a guide hole 68 of the support arm 67.
The guide pin 69 slidably fitted to the swash plate 6
0 through hole 61 and the outer peripheral surface of the rotary shaft 50 are included.

The piston 14 is provided with the engaging portion 70 which is engaged with the outer peripheral portion of the swash plate 60 while straddling the outer peripheral portion thereof, and the head portion 7 which is integrally provided with the engaging portion 70 and which is fitted into the cylinder bore 12.
2 and. The head 72 in the present embodiment is a hollow head to reduce the weight. The head 72, the cylinder bore 12, and the valve plate 20 cooperate to form a compression chamber. Further, the engagement portion 70 is engaged with the outer peripheral portion of the swash plate 60 via a pair of spherical crown shoes 76. The shoe 76 will be described in detail later.

The rotational movement of the swash plate 60 is converted into the reciprocating linear movement of the piston 14 via the shoe 76. In the intake stroke in which the piston 14 moves from top dead center to bottom dead center,
The refrigerant gas in the suction chamber 22 is sucked into the suction hole 32 and the suction valve 34.
And is sucked into the compression chamber in the cylinder bore 12. In the compression stroke in which the piston 14 moves from the bottom dead center to the top dead center, the refrigerant gas in the compression chamber inside the cylinder bore 12 is compressed and discharged into the discharge chamber 24 through the discharge hole 36 and the discharge valve 38. With the compression of the refrigerant gas, the piston 14
An axial compression reaction force acts. The compression reaction force is the piston 1
4, swash plate 60, rotary plate 62 and thrust bearing 6
It is received by the front housing 16 via 4.

An air supply passage 80 is provided penetrating the cylinder block 10. The air supply passage 80 forms a discharge chamber 24 and a swash plate chamber 86 formed between the front housing 16 and the cylinder block 10. Are connected. An electromagnetic control valve 90 is provided in the middle of the air supply passage 80, and current is supplied to a solenoid 92 of the electromagnetic control valve 90 by a control device (not shown) mainly composed of a computer such as a cooling load. Controlled according to information.

A discharge passage 100 is provided inside the rotary shaft 50. The discharge passage 100 has one end opened to the support hole 56 and the other end opened to the swash plate chamber 86. The support hole 56 is communicated with the suction chamber 22 via the discharge port 104.

This swash plate type compressor is a variable displacement type, and the pressure inside the swash plate chamber 86 is controlled by utilizing the pressure difference between the discharge chamber 24 on the high pressure side and the suction chamber 22 on the low pressure side. , The difference between the pressure of the compression chamber in the cylinder bore 12 acting before and after the piston 14 and the pressure of the swash plate chamber 86 is adjusted,
The inclination angle of the swash plate 60 is changed, the stroke of the piston 14 is changed, and the discharge capacity of the compressor is adjusted. Specifically, the pressure in the swash plate chamber 86 is controlled by controlling the excitation and demagnetization of the electromagnetic control valve 90 so that the swash plate chamber 86 is communicated with or cut off from the discharge chamber 24.

Cylinder block 10 and piston 14
Is made of an aluminum alloy, which is a kind of metal, and the outer peripheral surface of the piston 14 is coated with a fluororesin. By coating with a fluororesin, direct contact with the same kind of metal can be avoided, seizure can be prevented, and the fitting gap with the cylinder bore 12 can be made as small as possible. However, the material of the cylinder block 10 and the piston 14, the material of the coating layer, and the like are not limited to the above materials and the like, and other materials and the like may be used.

The engaging portion 70 of the piston 14 is generally U-shaped, and has a pair of arms 120 and 122 extending parallel to each other in a direction orthogonal to the central axis of the head 72, and the bases of the arms 120 and 122. And a connecting portion 124 for connecting the ends. A concave spherical contact surface 128 is formed on the side surfaces of the arm portions 120 and 122 that face each other so as to hold the shoe 76 and to be in sliding contact with the shoe 76. These two sliding contact surfaces 128 are located on the same spherical surface.

The base material of the swash plate 60 on which the shoes 76 slide is made of ductile cast iron. Although not shown, on the sliding contact surfaces 132 and 134 with which the shoe 76 slides, an aluminum sprayed film which is a metal sprayed film is formed on the surface of the base material, and a lubricating coating is further formed on the surface. This lubricating film is made by dispersing MoS ₂ and graphite in a synthetic resin, and sufficiently reduces the friction on the sliding contact surface to improve the sliding characteristics between the shoe 76 and the swash plate 60. It should be noted that the aluminum sprayed film prevents the base material from directly slidingly contacting and maintains good sliding characteristics even when the lubricant film is removed due to wear, peeling, etc. due to some factor. Function. It should be noted that the swash plate may have other configurations regarding the material of the base material of the swash plate, the type of the lubricating coating, the film thickness or not, and the film thickness of the aluminum sprayed film or the presence or absence thereof.

<Shape of shoe and sliding contact between shoe and swash plate> FIG. 2 is a front sectional view of the shoe 76. The shoe 76 has an outer surface having a piston-side engagement surface portion 150 that is generally convex spherical and engages with the piston 14, and a swash plate-side engagement surface portion 152 that is generally flat and engages the swash plate 60. It has a partitioned shape. Swash plate side engaging surface 1
Reference numeral 52 designates a central portion of the sliding contact surface 132 of the swash plate 60,
Approximately flat anti-swash plate sliding contact surface 154 that slidably contacts 134 (hereinafter abbreviated as "swash plate sliding contact surface 132"), and forms a peripheral portion and recedes with a step from anti-swash plate sliding contact surface 154. However, the peripheral surface 1 is connected to the piston-side engagement surface portion 150 at the outer peripheral edge (meaning that it is separated from the extended surface of the sliding contact surface 154 against the swash plate).
56 and an annular connecting surface 158 connecting the peripheral surface 156 and the sliding contact surface against the swash plate. In the drawing, the step amount between the peripheral surface 156 and the sliding contact surface 154 against the swash plate is exaggerated for easy understanding. Strictly speaking, the swash plate sliding contact surface 154 is a curved surface having a slightly medium height (middle convex), specifically, a convex spherical surface having an extremely large radius of curvature. In the present embodiment, the medium-high amount (distance difference in the height direction between the periphery and the center) is about 5.
It is said to be μm. In addition, the swash plate side engaging surface portion 152 is formed with a recess 160 at the center for storing lubricating oil and improving the sliding characteristics. Therefore,
The anti-swash plate sliding contact surface 154 is an annular surface. On the other hand, a recess 163 for pressing the knock pin at the time of molding is also formed in the center of the sliding surface 162 against the piston. The piston-side engagement surface portion 150 has a convex spherical spherical anti-piston sliding contact surface 162 corresponding to the sliding contact surface 128 of the piston 14, the anti-piston sliding contact surface 162, and the peripheral surface 15 of the swash plate side engagement surface portion 152.
6 and an outer peripheral curved surface 164 that connects the two.

Further explaining with reference to FIG. 1, the pair of shoes 76 is slidably held by the sliding contact surface 128 of the piston 14 on the sliding contact surface 162 of the piston, and the sliding contact surface 154 of the anti-swash plate. In contact with both sliding contact surfaces 132 and 134 which are both side surfaces of the outer peripheral portion of the swash plate 60, the outer peripheral portion of the swash plate 60 is sandwiched from both sides. That is, the shoe 76 slides on the swash plate 60 on the sliding contact surface 154 against the swash plate, and slides on the piston 14 on the sliding contact surface 162 against the piston. The pair of shoes 76 are designed such that the sliding contact surfaces 162 of the pair of pistons are located on substantially the same spherical surface in that state. That is, the shoe 76 has a shape close to a spherical crown having a height smaller than the hemisphere by about half the thickness of the swash plate 60.

The shoe 76 is composed of a base material and a hard metal plating film that covers the entire surface of the base material. The base material is made of an Al-Si alloy corresponding to A4032 containing aluminum as a main component and containing silicon so as to have a composition ratio near the eutectic. Further, the hard metal plating film is an electroless nickel plating film, has high hardness and strength, and prevents wear of the shoe 76 and scratches of the shoe 76. The thickness of the electroless nickel coating is about 50 on average.
μm, and this electroless nickel coating layer is omitted in FIG. The configuration of the material of the base material, the type of the hard metal plating film, the film thickness, etc. is not limited to that of the present embodiment, and, for example, the base material made of SUJ2 may be nitrided. You can also

FIG. 3 is an enlarged view showing a portion centering on the connecting surface 158 when the shoe 76 and the swash plate 60 are in sliding contact with each other. The connecting surface 158 exists at the step between the sliding contact surface 154 against the swash plate and the peripheral surface 156. Connecting surface 15
Reference numeral 8 denotes a slide contact side R portion 182 which is a corner R portion connecting the taper portion 180 and the tapered contact portion 154 with the swash plate slide contact surface 154.
And a peripheral side R part 184 which is another corner R part connecting the taper part 180 and the peripheral surface 156 (the boundary of each part is represented by a small circle for convenience). The step amount D between the swash plate sliding contact surface 154 and the peripheral surface 156 is set to a predetermined value. For example, in the shoe of this embodiment, it is 0.2 mm. Angle of taper portion 180, that is, taper portion 18
The angle α between 0 and the extended surface 186 of the sliding contact surface 154 against the swash plate
(Hereinafter, referred to as taper angle α), the radius of curvature r of the sliding contact side R portion 182 and the radius of curvature r ′ of the peripheral side R portion are also set to predetermined values. In the case of the shoe of this embodiment, the taper angle α is 45 °, and the radius of curvature r and the radius of curvature r ′ are both 0.2 mm.

FIG. 3 shows the swash plate 6 in a state where the shoe 76 is straight (the center line of the shoe is perpendicular to the sliding contact surface of the swash plate).
It shows a state of sliding contact with 0. As described above, since the anti-swash plate sliding contact surface 154 of the shoe 76 is a slightly middle-height curved surface, the anti-swash plate sliding contact surface 154 and the swash plate sliding contact surface 132 are in the sliding contact state. In between, a minutely-spaced gap 190 in which the amount of spacing gradually increases toward the outer peripheral side of the shoe 76.
Exists. For ease of understanding, in FIG.
90 is shown exaggerated. Due to the existence of the gap 190, a favorable lubricating oil film is formed between the sliding contact surfaces, and sliding characteristics are improved. The step amount D and the taper angle α
The extended surface 186 of the sliding contact surface 154 against the swash plate, which is the reference of the above, has a middle convex shape, so that the sliding contact surface 154 against the swash plate is orthogonal to the center line of the shoe 76 as described above. It is assumed to be a flat surface in contact with the plate sliding contact surface, and coincides with the swash plate sliding contact surface 132 in FIG. Also, the sliding contact surface 15 against the swash plate
4 and the peripheral surface 156 can be considered to be parallel. Therefore, the step amount D corresponds to the surface distance between the swash plate sliding contact surface 132 and the peripheral surface 156, and the taper angle α corresponds to the angle formed between the tapered portion 180 and the swash plate sliding contact surface 132. Has become.

A state in which the shoe 76 slides on the swash plate 60 (the shoe 76 moves relatively in the direction of → in FIG. 3).
In the above, the lubricating oil (not shown) existing on the surface of the swash plate 60 is the connecting surface 158 of the shoe 76 and the swash plate sliding contact surface 13.
The space is guided from the wedge-shaped space 192 having a wedge-shaped cross section to the gap 190. When the foreign matter 194 enters the wedge-shaped space 192, in the shoe 76 of the present embodiment, the taper angle α of the taper portion 180 and the curvature radius r of the sliding contact side R portion 182 are set to appropriate values, and the sliding characteristic is obtained. A relatively large foreign substance that has a large effect on the gap is prevented by the tapered portion 180 from entering the gap 190. That is, if a connecting surface 158 having an appropriate shape as shown in FIG. 3 is formed on the peripheral edge of the sliding contact surface 154 against the swash plate, foreign matter can be repelled while the lubricating oil is drawn between the sliding contact surfaces. It is possible. Therefore, a shoe having a properly shaped connecting surface 158 has good sliding characteristics.

The foreign material 194 shown in FIG. 3 is shown as a sphere having a diameter of about 100 μm. Such a large foreign object 1
Since 94 is in contact with the taper portion 180, the size of the taper angle α is a factor that determines the foreign matter repulsion characteristic. When the foreign matter is small, the foreign matter comes into contact with the sliding contact side R portion 182 instead of the tapered portion 180. Therefore, the radius of curvature r of the sliding contact side R portion 182 also becomes a factor that determines the foreign matter repulsion characteristic. Specifically, when a foreign substance comes into contact with the sliding contact side R portion 182, the contact plane between the sliding contact side R portion 182 and the extension surface 1 at both contact points.
It is determined by the angle formed by 86 (tangent plane angle). When the tangential plane angle is large, the repulsion property of the foreign matter is good, and when the tangential plane angle is small to some extent, the foreign matter is easily drawn between the sliding contact surfaces. If the foreign matter diameter is the same, the smaller the radius of curvature r of the sliding contact side R portion, the better the foreign matter repulsion characteristic. However, on the contrary, the drawing of the lubricating oil between the sliding contact surfaces is
The larger the radius of curvature r is, the better. Also,
As described above, there is a disadvantage due to the radius of curvature r being too small. Taking the above into consideration, the appropriate taper angle α and curvature radius r according to the purpose of the shoe may be determined in consideration of the balance between the foreign matter repelling effect and the lubricating oil drawing effect. is there. Specifically, depending on the target shoe, and in consideration of the ease of plastic flow in forging molding described later, for example, the above-mentioned [problem to be solved by the invention, problem solving means and effect] The values of the taper angle α and the radius of curvature r may be determined based on the description shown in FIG. Regarding the relationship between the particle diameter and the radius of curvature r, an unpublished patent application by the present applicant as described above (Japanese Patent Application No. 2001-139539).
You can refer to it in detail and as an aid to understanding.

In the case of the above embodiment, the step amount D between the peripheral surface 156 and the sliding contact surface 154 against the swash plate is set to 0.2 mm, and the foreign matter of less than 200 μm is included in the sliding contact surface 1 of the swash plate.
There is no biting between 32 and the peripheral surface 156. The step amount D is, for example, according to the assumed size of the foreign material, the shape of the connecting surface 158, etc., and considering the ease of plastic flow in forging forming described later, and the like. Problem, Problem Solving Means and Effects] may be set based on the description given in the section. In the above embodiment, the peripheral surface 156 is formed substantially parallel to the swash plate sliding contact surface 154. Instead of this, as shown in FIG.
It is also possible to incline the peripheral surface 156 with respect to the sliding contact surface 154 against the swash plate. In that case, the peripheral surface 156 and the swash plate sliding contact surface 154 are set as a range in which the resistance of the plastic flow of the material in the forging, which will be described in detail later, does not increase.
It is preferable that the angle β formed by the extension surface 186 of the above is less than 10 °. Further, the peripheral surface 156
The width (difference between the outer edge of the peripheral surface and the inner edge of the peripheral surface) may be determined in consideration of variations in the material amount of the material pieces, ease of plastic flow of the material, and the like. The larger the area of the sliding contact surface 154 against the swash plate is, the more stable the sliding contact state is. Therefore, in consideration of this point, the width of the peripheral surface 156 is equal to the effective sliding contact surface 15 against the swash plate.
It is desirable that the width be such that 4 can be secured. In addition,
The shape of the outer peripheral curved surface 164 that is the outermost edge of the shoe is not particularly limited. In the case of the present embodiment, the outermost edge of the shoe is a portion that absorbs the variation in the amount of material in the forging, as will be described later, and therefore has a slightly different shape for each shoe.

<Method of Manufacturing Shoe> An example of a method of manufacturing the shoe 76 of the above embodiment will be described. According to this manufacturing method, the shoe is manufactured through the steps of the material piece preparation step, the forging step, the heat treatment for heat treatment, the polishing step, the plating step, and the finish polishing step in that order. The forming method of the present invention is configured to include the material piece preparing step and the forging step.

The material is the above-mentioned aluminum alloy, and the material piece formed from the material has a columnar shape as shown in FIG. For details, see Material Piece 2
00 has a cylindrical shape having an outer diameter smaller than the outer diameter of the sliding contact surface 154 against the swash plate of the shoe 76 and a height higher than the height of the shoe 76, and one end surface thereof has a swash plate side engaging surface portion. 1
A recess 202 corresponding to the recess 160 formed in 52 is provided, and a recess 203 corresponding to the recess 163 formed in the piston side engaging surface portion 150 is provided on the other end surface. The material piece 200 is manufactured by forming a recess 202 and a recess 203 on a cylindrical material piece base. The material piece substrate is extruded from a billet made of an aluminum alloy having a predetermined composition obtained by casting, and a round bar having a predetermined diameter is produced by further drawing, and the round bar is subjected to an annealing treatment. The processed round bar is cut into a predetermined length by a sawing machine, shirring or the like, and further barrel-polished to smooth the surface of the cut material.

FIG. 6 shows how the recess 202 and the recess 203 are formed in the material piece 200. The recess 202 and the recess 203 are formed by so-called upset forging. The recess forming mold pair 206 used is a lower mold 21 supported by a base 210 via a spring damper 208.
2 and an upper mold 213 facing the lower mold 212. The lower mold 212 has a concave portion 214 in which the material piece base body 204 is set, and the concave portion 214 has an inner diameter that is slightly larger than the outer diameter of the material piece base body 204 and a depth that is higher than the material piece base body 204. It is formed shallower than that. The lower die 212 is provided with a circular through hole 215 that communicates with the center of the lower portion of the recess 214, and the base 210 is provided with a cylindrical pin 216 having one end fixedly supported. The end is inserted into the circular through hole 215. The bottom of the upper mold 213 is the material piece base 20.
4 has a recess 218 formed so as to hit the upper end of
The recess 218 has an inner diameter somewhat larger than the outer diameter of the material piece base body 204, and a protrusion 219 is provided at the center of the bottom. When the upper die 213 is lowered with the material piece base body 204 set in the concave portion 214 of the lower die 212, the upper die 213 and the lower die 212 are closed, and the lower die 212 with respect to the base 210. By descending, pin 2
One end of 16 projects into the recess 214. As a result, the tip end of the pin 216 and the upper mold protrusion 219 are installed on both end surfaces of the material piece base body 204, and the recesses 202 and the recesses 203 are formed on the respective end surfaces. 200 is completed.

The material piece preparation process is completed as described above. The material piece preparation process is not limited to the above-mentioned form. For example, when a shoe is formed by using a spherical material piece, the material piece is a step of manufacturing a spherical material piece. In this case, the rod-shaped material is cut, pressed, and then combined with various processes such as flushing and grinding. Further, when the material piece having no recess is forged, the formation of the recess is not necessary in the material piece preparing step. Note that the person who performs the forging process does not have to perform the material piece preparing step, and a predetermined material piece may be purchased and procured, and the material piece may be used for forging. In that case, the material piece preparing step is a step of procuring the material piece.

Next, the material piece 200 is subjected to forging forming in the forging step. The state of the forging process is schematically shown in FIG. The upper mold 220 and the lower mold 222 are forged.
Using a pair of molds 224 composed of and, it is performed cold by a forging device. The mold pair 224 includes an upper mold 220 and a lower mold 2.
22 together with the shoe 76, the shoe 76
A cavity having substantially the same shape as is formed. Strictly speaking, a cavity having a shape approximately the same as the shoe base material shape is formed, taking into account the film thickness of the electroless nickel coating to be subsequently applied to the base material surface, and forming a cavity that is as small as the film thickness. . The lower die 222 has a protrusion 226 formed in the center thereof so as to fit almost exactly into the recess 202 of the material piece 200.
And when the material piece 200 is set in the mold,
The material piece 200 is positioned by inserting the protrusion 226 into the formed recess 202. On the other hand, the upper die 220 is provided with a movable knock pin 227, and the tip end portion of the knock pin 227 is fitted into the recess 203 formed in the material piece 200. In this way, if the recess is formed in advance before forging, the material can be set at the proper position in the mold by using the recess, and the plastic flow in forging is isotropic and forged. In addition, the shoe 76 is of high quality with little variation in shape and size. After setting the material piece 200, the upper mold 22
The shoe 76 is forged by lowering 0 and closing the die.

More specifically, the mold surface of the upper mold 220 is a mold for molding the piston side engaging surface portion 150 of the shoe 76, and the upper mold 220 corresponds to the first mold, The mold surface of the lower mold 222 is a mold for molding the swash plate side engagement surface portion 152 of the shoe 76, and the lower mold 222 corresponds to the second mold. In the closed state, the lower mold 22
2, a portion for forming the sliding contact surface 154 against the swash plate, and the upper mold 220.
The distance from the mold surface determines the height dimension of the shoe 76 (strictly speaking, the height dimension of the base material 152). In addition, this mold pair 224 is designed to close the mold parts by abutting the peripheral parts of the mold surfaces of the upper mold 220 and the lower mold 222 (so-called mold contact). Contributes to the improvement of the height accuracy of the shoe. However, since the abutting of the mold also affects the life of the mold, it is desirable to select and determine the necessity of the mold contact, the mold contact site, etc., also in consideration of the fact.

In the cavity of the mold pair 224, there is an extra space 228 which remains without being filled with the material in the outermost peripheral portion, and the extra space 228 serves as a space for absorbing the variation in the material amount. Become. In other words, the lower mold 22
The part of the second mold surface that forms the peripheral surface 156 is extended toward the periphery, and the part of the upper mold 220 that forms the anti-piston sliding contact surface 162 is extended. The portion surrounded by these extended portions becomes the surplus space 228. Conversely speaking, the material amount is set so that such a surplus space 228 remains. The outer peripheral edge portion of the shoe formed in the excess space 228 has a slight variation in shape due to variation in the amount of material. However, the outer peripheral curved surface 164, which is the surface of that portion, does not make sliding contact with either the piston or the swash plate in the state where it is assembled to the swash plate compressor, and the above variation affects the performance of the swash plate compressor. Does not reach.

When the material piece 200 is set in the mold pair 224 and the closing of the mold pair 224 is started, the material is pressed from the vertical direction and starts to deform so as to expand toward the surroundings. That is, the material generally begins to flow plastically towards the surroundings. As the upper mold 220 descends, the end surface of the material advances toward the surroundings, and when the mold pair 224 is closed, the material is exactly pressed against the mold surfaces of the upper mold 220 and the lower mold 222, and the excess The cavity is filled, leaving only the space 228. This completes the forging of the shoe. When the forged shoe is taken out from the mold pair 224, when the upper die 220 is raised, the knock pin 227 is pushed down so that the shoe 76 is separated without sticking to the upper die 220, and the shoe 76 is taken out. Easy to do.

FIG. 8 shows the plastic flow of the material on the outer periphery of the shoe. In the forging process of the shoe 76 of the present embodiment, the material spreads toward the outer periphery, but the step portion 230 corresponding to the part of the lower die 222 that forms the joining surface 158 has resistance to plastic flow. Can be. But,
In the shoe having the above-described shape, the peripheral surface 156 and the swash plate sliding contact surface 1
Since the amount of step D with respect to 54 is comparatively small, plastic resistance flows over the stepped portion 230 (covers the stepped portion 230) and the resistance thereof can be said to be quite small. Therefore, a large forming load is not required and the amount of springback after forming is small. Further, even when the material piece 200 having a larger amount of material than the regular amount is forged by the mold pair 224, the increase in resistance to plastic flow is small. Therefore, in the shoe of this embodiment, due to its shape characteristic, the variation in the molding dimension due to the variation in the amount of material is small.

For comparison, a shoe provided with the side surface portion connecting the swash plate side engagement surface portion and the piston side engagement surface portion and the forging of the shoe will be described.
FIG. 9 shows a front sectional view of the aforementioned shoe as a comparative example. The outer surface of the shoe 250 of this comparative example is roughly divided into a piston-side engagement surface portion 252, a swash plate-side engagement surface portion 254, and a side surface portion 256 connecting both of them. Side part 25
Reference numeral 6 denotes a taper surface 260 that makes an angle of about 45 ° with respect to the swash plate sliding contact surface 258 of the swash plate side engagement surface portion 254, and the piston surface sliding contact surface 262 of the taper surface 260 and the piston side engagement surface portion 252. And an outer peripheral curved surface 264 that connects Similar to the shoe 76 of the embodiment, the tapered surface 260 and the swash plate sliding contact surface 258 are adjacent to each other with a small corner R interposed therebetween,
The portion forming the outer peripheral curved surface 264 is a portion that absorbs the variation in the material. Also, similarly,
Swash plate side engagement surface portion 254 and piston side engagement surface portion 252
A recess 266 and a recess 268 are formed in each of them.

FIG. 10 schematically shows the forging process for forming the shoe 250 of the comparative example. With regard to molds and the like, parts having the same functions as those shown in FIG. 7 are designated by the same reference numerals. Comparative shoe 250
The forging is also performed by the same method using the same mold pair 224 as in the case of the shoe of the embodiment. Mold pair 224
2 is different in that the lower mold 222 has a mold surface capable of molding the tapered surface 260 of the side surface portion 256. Similarly, in the cavity, a surplus space 228 that remains without being filled with the material is present at the outermost periphery as a space for absorbing the variation in the material amount.

FIG. 11 shows the state of plastic flow of the material on the outer peripheral portion of the shoe 250 of the shoe 250 of the comparative example. Similarly, in the case of forging the shoe 250 of the comparative example, the material spreads toward the outer circumference. What is different from the case of the shoe 76 of the embodiment is that the mold surface 270 forming the side surface portion 256 exists at the destination where the end surface of the material advances. After the plastic flow progresses and the end surface of the material comes into contact with the portion of the die surface 270 (A in the figure), the presence of the die surface 270 provides a large resistance to the plastic flow. Specifically, in order to form the corner R, the force (force in the direction of a in the figure) for pressing the material against the corner portion (B in the figure) of the lower die 222, the die surface while pressing it against the die surface 270. A large forming load must be applied to the material by requiring a force (a force in the direction of b in the drawing) to move the material along the 270 toward the surplus space 228. When the material piece 200 having a larger amount of material than the regular amount is forged by the mold pair 224, a large forming load is particularly required. If a large forming load is required, the material also receives a large force, so that the amount of springback after forming increases, for example. To conclude, in the shoe 250 of the comparative example, a large resistance to plastic flow due to its shape occurs, and as a result, the variation in the amount of material causes the large variation in the molding dimension. In addition, since a large forming load must be applied to the mold, a large load is imposed on the mold.For example, when molding a shoe made of a high-strength material such as high carbon chrome bearing steel, the strength of the mold must be increased. This is a factor that raises the manufacturing cost.

The reaction force from the material received by the mold during forging was actually compared between the shoe of the embodiment and the shoe of the comparative example. The large reaction force means
This means that the forming load must be increased, and that the material receives a large force during forging.
This comparison is based on CAE (computer-aided experimen
t: Computer-assisted experiment). Both of the shoe materials are the above-mentioned aluminum alloys, the regular material amount is 3.00 g, and the state of forming from the material piece of the regular material amount and the state of forming from the material piece of the material amount 0.04 g more than the regular material amount. The two states of and were evaluated respectively. As a result, FIG. 12 shows a change in reaction force with the passage of forming time when each of the shoe 76 of the embodiment and the shoe 250 of the comparative example is forged, and FIG. 13 shows the material in both cases. The change of the maximum reaction force with respect to the change of quantity is shown.

According to FIG. 12, in any shoe, the reaction force gradually increases from the start of molding, and when the plastic flow of the material to the outer peripheral edge of the shoe begins, the increasing gradient of the reaction force increases. It becomes large and becomes the maximum reaction force immediately before the end of molding. When the shoe of the embodiment and the shoe of the comparative example are compared with each other in the case of molding from the material piece of the regular material amount, it can be seen that the shoe of the comparative example has a larger reaction force as described above. The maximum reaction force is about 9 t (ton) in the case of the shoe of the embodiment, whereas it is as large as about 15 t in the shoe of the comparative example. When the amount of the raw material is increased by 0.04 g, the reaction force from the raw material increases regardless of whether the shoe of the embodiment or the shoe of the comparative example is forged. However, in the case of the shoe of the embodiment, the maximum reaction force is about 12t, and the increase amount of the maximum reaction force is about 3t.
t is small. On the other hand, in the case of the shoe of the comparative example, the maximum reaction force is about 26t, and the increase amount of the maximum reaction force is as large as 11t. FIG. 13 in which the results are plotted
Indicates that the shoe of the embodiment has a smaller increase rate of the reaction force even when the amount of material increases. From the above results, it can be easily understood that the shoe of the embodiment requires a smaller molding load than the shoe of the comparative example. Further, it can be confirmed that the shoe of the embodiment is a shoe with small dimensional variation and high dimensional accuracy because the difference in the force received by the material is small even if the material amount varies.

The forging is performed from a cylindrical material piece, but it can be performed from a spherical material piece and various shapes of material pieces. Regardless of the shape of the material piece, the shoe of the present invention has a small forming load required for forming and forging, and the increase rate of the reaction force due to the increase in the amount of the material is small.

In the forging step, the forming from the material piece to the final shape is performed in one step, but several forgings with low workability are sequentially performed to form a forging formed by multiple steps. It can be a process. For example, it is possible to perform forging once to an intermediate shape (a shape in which the outer peripheral edge is not formed), and then perform forging including the outer peripheral edge as described above. In that case, the subsequent forging step becomes the forging step in the forming method of the present invention, and the shoe front body having the intermediate shape corresponds to the material piece. In addition, it is molded to a shape very close to the final shape (the shape of the outer peripheral edge is almost completed), and then, for the purpose of dimension adjustment,
It is also possible to perform finish forging. in this case,
The above-mentioned forging step is the forging step in the forming method of the present invention. When molding is performed in a plurality of steps, the molded product may be subjected to an annealing treatment or the like between any of the steps.

The shoe formed in the forging process was subjected to T6 treatment and T7 treatment (JIS H 0
A heat treatment such as 001) is performed. In addition, in the polishing step, polishing processing for surface smoothing and the like is performed. In this polishing process, there are 2 types of surface polishing and barrel polishing.
Perform two polishing processes. For surface polishing, the sliding contact surface 154 against the swash plate is used.
The surface is polished by using a flat polishing machine to align some shoes and using loose abrasive grains. In addition, in this plane polishing, the sliding contact surface 154 against the swash plate can be formed into a convex shape. Barrel polishing is for polishing the entire surface of the shoe, and is performed by inserting the shoe together with loose abrasive grains into a barrel polishing machine. Either of these two polishing processes may be performed first. Alternatively, a plating process may be performed to apply an electroless nickel plating film, which is a hard metal plating film, on the surface of the shoe. Polishing is performed in the finish polishing step. In this finishing polishing step, barrel polishing is mainly performed, and if necessary, plane polishing is performed. Buffing may be performed. The shoe 76 is completed through the steps described above in an appropriate order. The manufacturing method is not limited to the above-described manufacturing method, and the shoe of the present invention can be manufactured by various methods according to the specifications of the shoe to be manufactured.

The above description of the manufacturing method has been centered on the method of manufacturing a shoe made of an aluminum alloy, but in the case of a shoe made of an iron alloy such as high carbon chrome bearing steel, for example, after the forging step described above, If necessary, tempering heat treatment such as quenching is performed, and a shoe is completed through a polishing process, a nitriding process, a finish polishing process, and the like. In the heat treatment for heat treatment, the shoe may be deformed due to thermal strain or the like. In that case, the forming dimension in the forging step may be set in anticipation of the deformation. The reason why such a manufacturing method can be adopted is that the shoe and the molding method of the present invention have high dimensional accuracy. In other words, being able to form a shoe with high dimensional accuracy leads to the merit that the dimension adjustment after forging and forming can be reduced and the shoe can be manufactured at low cost.

[0075]

[Brief description of drawings]

FIG. 1 is a front sectional view showing a swash plate type compressor provided with a shoe according to an embodiment of the present invention.

FIG. 2 is a front sectional view showing a shoe arranged in the swash plate compressor shown in FIG.

FIG. 3 is an enlarged cross-sectional view showing a portion centered on a connecting surface in a state where the shoe shown in FIG. 2 is in sliding contact with a swash plate.

FIG. 4 is another embodiment of the present invention,
It is sectional drawing which shows the shoe which a peripheral surface inclines with respect to a swash plate sliding contact surface.

FIG. 5 shows a material piece used when the shoe of the above embodiment is formed by forging.

FIG. 6 shows how a recess is formed in a material piece base in a material piece preparing step of a molding method according to an embodiment of the present invention.

FIG. 7 schematically shows a state of a forging step for forming the shoe of the embodiment.

FIG. 8 shows a state of plastic flow of a material on an outer peripheral portion of the shoe during forging of the shoe of the embodiment.

FIG. 9 is a front sectional view showing a shoe of a comparative example.

FIG. 10 schematically shows a state of a forging step of forming a shoe of a comparative example.

FIG. 11 shows a state of plastic flow of a material on an outer peripheral portion of a shoe during forging of a shoe of a comparative example.

FIG. 12 is a graph showing a change in reaction force with respect to a lapse of molding time when each of the shoe of the embodiment and the shoe of the comparative example is forged.

FIG. 13 is a graph showing changes in the maximum reaction force with respect to changes in the amount of material when each of the shoe of the embodiment and the shoe of the comparative example is forged.

[Explanation of symbols]

14: Single-headed piston 60: Swash plate 76: Shoe 12
8: Sliding contact surface 132, 134: Sliding contact surface 150: Piston side engaging surface portion 152: Swash plate side engaging surface portion 154: Anti-swash plate sliding contact surface 156: Peripheral surface 158: Connecting surface 16
2: Sliding surface against piston 164: Curved outer peripheral edge surface 180:
Tapered part 182: R part on sliding contact side 184: R part on peripheral edge side
186: Extension surface 200: Material piece 220: Lower mold
222: upper mold 224: mold pair 228: surplus space

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3H076 AA06 AA07 BB17 BB43 BB50                       CC33                 4E087 AA08 AA10 CA14 CB03 DB03                       DB04 DB15 DB22 DB24 EC12                       EC46 HA00

Claims (6)

[Claims] 1. A swash plate type compressor is provided between a swash plate and a piston, the outer surface of which is a generally convex spherical surface and which engages with the piston. A spherical crown-shaped shoe that is generally divided into a swash plate side engaging surface portion that engages with the plate, wherein the swash plate side engaging surface portion constitutes a central portion of the swash plate side engaging surface portion, and A substantially flat anti-swash plate sliding contact surface that is in sliding contact with the surface of the plate, and a peripheral edge portion of the swash plate side engaging surface portion, and retreats with a step from the anti-swash plate sliding contact surface at the outer peripheral edge A shoe for a swash plate compressor, comprising: a peripheral surface connected to the piston-side engagement surface portion; and an annular connecting surface that connects the peripheral surface and the sliding contact surface against the swash plate. 2. The shoe for a swash plate compressor according to claim 1, wherein a step between the sliding contact surface against the swash plate and the peripheral surface is 0.02 mm or more and 0.5 mm or less. 3. The shoe for a swash plate compressor according to claim 1, wherein the peripheral surface and the sliding contact surface against the swash plate are substantially parallel to each other. 4. The connecting surface has a taper portion having a truncated cone peripheral surface shape that widens toward the peripheral surface, and a corner R portion connecting the taper portion and the swash plate sliding contact surface. The swash plate compressor shoe according to any one of claims 1 to 3. 5. The shoe includes a first mold having a mold surface for molding the piston side engaging surface portion and a second mold having a mold surface for molding the swash plate side engaging surface portion. Using a pair of molds provided, a material piece having an outer diameter smaller than the diameter of the sliding contact surface of the swash plate was set at the center of the pair of molds, and the mold pair was forged by closing the mold pair. The shoe for a swash plate compressor according to any one of claims 1 to 4. 6. In a swash plate compressor, a piston-side engaging surface portion that is disposed between a swash plate and a piston and has an outer surface that is a generally convex spherical surface and that engages with the piston, and a generally planar surface that is inclined. Substantially divided into the swash plate side engaging surface portion that engages with the plate,
The swash plate side engagement surface portion (a) constitutes a central portion of the swash plate side engagement surface portion, and a substantially flat anti-swash plate sliding contact surface that is in sliding contact with the surface of the swash plate, (b) the swash plate A peripheral edge portion of the plate side engaging surface portion, which is retracted with a step from the anti-swash plate sliding contact surface, and a peripheral edge surface which is connected to the piston side engaging surface portion at the outer peripheral edge,
(c) A method of forming a spherical crown shoe having an annular connecting surface that connects the peripheral surface and the sliding contact surface against the swash plate, wherein the outer diameter is smaller than the outer diameter of the sliding contact surface against the swash plate. A material piece preparing step of preparing a material piece having: a first mold having a mold surface for molding the piston side engaging surface portion; and a second mold surface having a mold surface for molding the swash plate side engaging surface portion. A die pair including a die, the material piece is set in the center of the die pair, and the die pair is closed to forge the spherical crown shoe. A method for forming shoes for a swash plate compressor.