JP2003129950A - Variable displacement compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively manufacture a detent mechanism of constant velocity type preventing the rotation of an oscillation plate and having a simple structure in an oscillation plate type variable displacement compressor. SOLUTION: Three pins 13 protrude at an interval of 120 degrees uniformly in the radial direction from the surroundings of the oscillation plate 6 driving a piston 8, Their tips are inserted into central holes 141 of steel balls 14, respectively, so that the steel balls 14 can rotate and slide in the directions of pins 13. These steel balls 14 are slidably engaged with three guide grooves 1a provided on an inner face of a housing 1 in parallel with a drive shaft 4 and having a circular cross section, respectively. When a drive plate 5 rotates together with the drive shaft 4, the movement performed by the oscillation plate 6 becomes pure oscillation movement and does not include components of reciprocating rotary movement at all, thereby causing no vibration and noise. Since the detent mechanism has the constant velocity property, but has not a complicated structural part around the drive shaft 4 and the oscillation plate 6, it can be inexpensively manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable capacity compressor mainly used for compressing an arbitrary amount of refrigerant in an air conditioner, and in particular, it includes a rocking plate inclined with respect to a drive shaft. A plurality of pistons are reciprocated by the oscillating plate, and the inclination angle of the oscillating plate can be changed steplessly in order to change the discharge capacity. "Plate type variable capacity compressor".

[0002]

2. Description of the Related Art In a conventional oscillating plate type variable displacement compressor, as an anti-rotation mechanism for preventing rotation of the oscillating plate, for example, as described in Japanese Patent No. A fork-shaped holding portion protruding in a radial direction from one location is slidably engaged with one guide rail mounted on the inner surface of the casing so as to be parallel to the drive shaft. It is commonly used. However, when this type of detent mechanism is used, the motion of the oscillating plate does not become a pure oscillating motion that does not include any rotational direction component, and in addition to the oscillating motion, a reciprocating rotary motion of a minute angle is also possible. A certain rotational vibration occurs. When the drive shaft rotates at a high speed, this rotational vibration may increase the load of sliding parts such as the engaging part of the holding part and the guide rail of the rotation stop mechanism, or increase the vibration of the entire compressor. Undesired problems occur.

This is because the anti-rotation mechanism described above does not have so-called "constant speed", and in the universal joint mechanism that does not have constant speed like the well-known hook joint, the input If the output shaft is tilted with respect to the input shaft even if the rotary motion of constant speed is applied to the shaft, the rotary motion of constant speed does not appear on the output shaft, and the rotary motion of which the rotary speed fluctuates is taken out. For the same reason. This problem is an obstacle to realizing a high degree of quietness and reliability, or a reduction in size and weight, which has been particularly needed in recent years in refrigerant compressors for vehicles and the like.

On the other hand, paying attention to this problem, as described in, for example, Japanese Patent Laid-Open No. 5-133425, as a detent mechanism for connecting a rocking plate and a compressor housing,
The so-called "constant speed universal joint" is used to allow only pure oscillating motion of the oscillating plate and prevent the generation of reciprocating rotational motion components, which results from the non-uniform speed of the detent mechanism as described above. Attempts have been made to eliminate the problem, but in this improvement plan, a constant velocity universal joint mechanism is provided in the central portion of the oscillating plate, whereby the oscillating plate and the compressor housing, which is a detent member, are connected. It is connected. This constant velocity universal joint mechanism is provided on the outer periphery of the drive shaft, is rotatable and axially slidable with respect to the drive shaft, and has a guide groove for a plurality of balls on its outer periphery. Since the support sleeve is included, another problem arises in that the drive shaft has a double structure, the structure of the compressor is complicated, the body size is increased, and the manufacturing cost is increased.

Further, this constant velocity universal joint mechanism is
Considering the case where ₂ is applied to a compressor that uses a refrigerant, the torque applied to the drive shaft generally increases as compared with a compressor that uses CFCs as a refrigerant. The load applied to is also increased. In this case, it is advantageous that the load is smaller as the portion receiving the load of the detent is more outward with respect to the center of the drive shaft. However, the detent mechanism arranged at the center of the oscillating plate is advantageous. Due to the above limitation, it is necessary to dispose it in a space of a limited size inside the oscillating plate, which imposes an unfavorable condition as a mechanism for receiving a high load.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and an object thereof is to solve those problems by a novel means.

[0007]

As a means for solving this problem, the present invention provides an oscillating plate type variable displacement compressor as set forth in claim 1 of the appended claims.

In the oscillating plate type variable displacement compressor of the present invention, as a rotation stopping mechanism for preventing the rotation of the oscillating plate, the oscillating plate is radially arranged with a space of 120 degrees from each other. It is provided integrally with the three extending pins and the housing, is parallel to the drive shaft, and is evenly arranged around it with a mutual positional relationship of 120 degrees.
Since there are provided the three guide grooves which are always engaged with the tips of the three pins, the detent mechanism constitutes a constant velocity universal joint, so that the rocking plate is reciprocally rotated. It only makes a pure rocking motion without any components. Therefore, it is possible to reliably prevent the generation of vibration, noise, and the like from the detent mechanism and the compressor as a whole. Further, since this detent mechanism has a simple structure and does not have a complicated structure in the central portion, it can be downsized including the entire compressor, and there is no risk of an increase in cost.

In the most preferred embodiment of the present invention, the three guide grooves are circular in cross-section and formed so that the steel balls are always engaged with them and pass through the center of the steel balls. Three pins, each of which has a cylindrical tip extending radially from the oscillating plate, are rotatably and slidably inserted into the center hole having a circular cross section. As a result, the tips of the three pins are always engaged with the three guide grooves via the steel balls, so that friction is reduced and sliding is performed smoothly.

In the oscillating plate type variable displacement compressor of the present invention, the three pins have a structure capable of expanding and contracting in the direction of their respective central axes, and they are always extended by means such as a compression spring. It can also be carried out by incorporating a detent mechanism having an extremely simple structure in which the tips of the three pins are always engaged with the three guide grooves by urging.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The accompanying drawings show a preferred embodiment of an oscillating plate type variable displacement compressor of the present invention. In FIG. 1, which shows a vertical cross-sectional structure of the entire compressor in an operating state that provides the maximum discharge capacity, 1 is a front housing which is a part of the outer shell of the compressor, and 2 is a front by a fastening means such as a through bolt (not shown). The middle housing integrated with the housing 1 is shown. Inside the middle housing 2, a plurality of (for example, five) cylinder bores 21 are arranged in the lateral direction (“axial direction” described later) in FIG.
It is formed approximately evenly around the centerline. Reference numeral 3 denotes a rear housing, which is integrated with the middle housing 2 by a fastening means (not shown). A suction chamber 31 is formed as a space in the outer peripheral portion inside the rear housing 3, and a space is provided in the central portion. Is formed as a discharge chamber 32.

Reference numeral 4 is a drive shaft for receiving rotational power from an external power source, and a disc portion 4a is integrally formed so as to be orthogonal to it. Two arms 41 are formed in parallel with each other at a predetermined distance from a part of the outer circumference of the disk portion 4a so as to project in the axial direction. The drive shaft 4 is supported by the integrated front housing 1 and middle housing 2 via radial bearings 402 and 404, and is also supported by a thrust bearing 403 supporting the back surface of the disc portion 4a. The front housing 1 also supports the direction. In addition, a shaft sealing device 401 is provided on the outer side of these bearing portions.
Is provided to prevent fluid from leaking to the outside from around the drive shaft 4.

Reference numeral 5 denotes a drive plate, which is provided with a disk portion 5a having a substantially disc shape, a cylindrical portion 5b formed at the center thereof, and an arm portion 5c protruding from a part of the disk portion 5a. The arm portion 5c is formed with a long hole 51 having a predetermined shape serving as a cam, and the arm pin 42 fixed to the arm 41 on the drive shaft 4 side is slidably engaged with the long hole 51. . Thereby the drive plate 5 can rotate with the drive shaft 4. A swing plate 6 that does not rotate is supported on the drive plate 5 via bearings 501 and 601. Although the bearing 501 is a thrust bearing, a thrust bearing is also used for the other bearing 601. This is because the swing plate 6 can be slightly moved in the radial direction with respect to the drive plate 5. Therefore, a small radial gap c is formed between the cylindrical portion 5b of the drive plate 5 and the central opening of the oscillating plate 6 that receives it. Reference numeral 12 is a lock nut for mounting the bearing 601.

The same number of spherical recesses 6a as the above-mentioned cylinder bores 21 are formed in the peripheral portion of the oscillating plate 6, and a spherical end portion 71 formed at one end of the same number of piston rods 7 engages with this. is doing. Further, the pistons 8 slidably inserted into the respective cylinder bores 21 are also formed with spherical recesses 8a, to which the spherical end portions 72 formed at the other ends of the piston rods 7 engage. is doing.

Reference numeral 9 denotes a valve port plate made of a thick plate, and at least one suction port 9a and at least one discharge port 9b are opened at positions corresponding to the cylinder bores 21 so as to penetrate therethrough. Each suction port 9a of the valve port plate 9 is closed from the cylinder bore 21 side by a reed valve-shaped suction valve 20 formed in each part of a suction valve plate 19 made of one thin spring steel plate. Each discharge port 9b is closed from the discharge chamber 32 side by a reed valve-shaped discharge valve portion formed in the peripheral portion of the discharge valve plate 10 which is also made of one thin spring steel plate. The discharge valve plate 10 is simultaneously fixed when the valve retainer 11 protecting it is screwed onto the valve port plate 9. Further, when the middle housing 2 and the rear housing 3 are fastened and integrated, the valve port plate 9 and the suction valve plate 19 are sandwiched and fixed between them.

Reference numeral 15 is a sleeve loosely fitted to the drive shaft 4 so that it can freely slide on the drive shaft 4 in the axial direction by its center hole, and its outer shape is spherical. , This spherical outer surface is the drive plate 5 described above.
Slidably engages a cylindrical inner surface formed in the center of the cylindrical portion 5b. As shown in FIG. 5, the cylindrical portion 5b of the drive plate 5 is pivotally attached to the sleeve 15 by two sleeve pins 16 in a direction orthogonal to the drive shaft 4. Therefore, when the sleeve 15 slides on the drive shaft 4 in the axial direction, the drive plate 5 and the oscillating plate 6 can rotate around the sleeve pin 16. The length of each piston rod 7 is constant, and since the arm pin 42 attached to the drive shaft 4 side engages with the long hole 51 of the drive plate 5, the drive shaft 5 moves as the sleeve 15 moves. The tilt angles of the drive plate 5 and the oscillating plate 6 with respect to 4 change, and the strokes of all the pistons 8 change at the same time by the same amount. As a result, the discharge capacity of the compressor changes continuously.

The rocking plate 6 rotates together with the drive shaft 4 and the drive plate 5 while permitting the tilting of the rocking plate 6 with respect to the drive shaft 4 and the rocking motion of the rocking plate 6 by the rotation of the drive plate 5. Must be prevented, the rocking plate 6 is provided with a rotation stopping mechanism, but as described above,
In a conventional oscillating plate type variable displacement compressor, the detent mechanism does not have a uniform speed, which may cause vibration and noise, or when a detent mechanism with a uniform speed is used, However, there is a problem in that the compressor becomes complicated and the cost increases, and the size of the compressor becomes large.

In order to solve this problem, in the illustrated embodiment of the present invention, a detent mechanism having a constant velocity can be constructed simply and without increasing the size of the compressor.
On the inner surface of the front housing chamber 1b formed as a space inside the front housing 1, there are three guide grooves parallel to the drive shaft 4 and evenly spaced around the drive shaft 4 by 120 degrees. 1a is formed and the swing plate 6 is formed.
The three pins 13 are evenly protruded radially from the outer peripheral part of the pin 13 at intervals of 120 degrees, and the outer ends of the respective pins 13 are slidably engaged with the guide grooves 1a. These 3
The pins 13 of the book will be collectively referred to as "tripod (tripod) pins".

In the illustrated embodiment, the guide groove 1a is further advanced so as to smoothly engage and slide the engaging portion between the outer end (tip) of the tripod pin 13 and the guide groove 1a.
5, the steel ball 14 is attached to each tip of the tripod pin 13 so as to be rotatable and slidable in the direction of the central axis of each pin 13. Therefore, at least a portion of the pin 13 near the tip,
A central hole 14 passing through the central axis of the steel ball 14 attached to it
All of the cross-sectional shapes of 1 are circular, and needless to say, the outer shape of the steel ball 14 is spherical.

Next, the operation of the oscillating plate type variable displacement compressor of the illustrated embodiment will be described. When the drive shaft 4 is rotationally driven by an external power source such as an internal combustion engine or a motor mounted on the vehicle, the arm 4 is rotated with respect to the disc portion 4a of the drive shaft 4.
1, the drive plate 5 connected via the arm pin 42, the long hole 51, the arm portion 5c, etc. rotates integrally with the drive shaft 4. However, since the oscillating plate 6 is supported by the drive plate 5 via the bearings 501 and 601, it does not rotate, and the drive plate 5 does not rotate.
However, only when it is tilted with respect to an imaginary plane orthogonal to the drive shaft 4, the rocking motion having a magnitude corresponding to the tilt angle is performed. As a result, the plurality of pistons 8 connected to the swing plate 6 via the piston rods 7 reciprocate in the respective cylinder bores 21.

Of the plurality of pistons 8, the working chamber formed on the top surface of the piston 8 in the suction stroke expands to a low pressure, so that the fluid in the suction chamber 31 to be compressed, for example, the air conditioner. The refrigerant flows in by opening the suction valve 20 provided at the suction port 9a of the valve port plate 9. On the contrary, since the working chamber formed on the top surface of the piston 8 in the pumping stroke is contracted, the fluid inside thereof is compressed and becomes high pressure, and the discharge provided in the discharge port 9b of the valve port plate 9 is discharged. The valve portion of the valve plate 10 is pushed open to be discharged into the discharge chamber 32. The discharge capacity in that case is approximately proportional to the stroke length of the piston 8 determined by the tilt angles of the drive plate 5 and the oscillating plate 6.

As described above, when the inclination angles of the drive plate 5 and the oscillating plate 6 are changed, the discharge capacity of the compressor changes. Therefore, in order to control the discharge capacity, all of the compressors in the illustrated embodiment are controlled. The pressure in the front housing chamber 1b, which is the back pressure of the piston 8, is changed by using a pressure control valve or the like (not shown). Normally, an intermediate pressure between the high pressure in the discharge chamber 32 and the low pressure in the suction chamber 31 is introduced from the pressure control valve into the front housing chamber 1b. When the pressure in the front housing chamber 1b, that is, the back pressure of the piston 8, is increased, the balance with the pressure in the working chamber formed on the top surface of each piston 8 is lost, so that a new balance can be obtained. The average position of the plurality of pistons 8 moves toward a position close to the valve port plate 9. As a result, the strokes of all the pistons 8 are reduced all at once, so that the discharge capacity of the compressor is reduced steplessly.

FIG. 2 shows a state in which the stroke of the piston 8 becomes zero and the discharge capacity also becomes zero. In this case, the pressure in the front housing chamber 1b is maximized, and the tilt angles of the drive plate 5 and the swing plate 6 are zero (actually, the arm pin 42 on the drive shaft 4 side is a long hole of the drive plate). By contacting the end of 51, an inclination angle of about several degrees remains.) Therefore, even if the drive plate 5 rotates with the drive shaft 4, the swing plate 6 does not swing at all and stands still. ing. Therefore, all the pistons 8 are at the top dead center position and the cylinder bore 21
There is no reciprocating motion inside.

On the contrary, when the pressure control valve (not shown) is operated to reduce the pressure in the front housing chamber 1b, the back pressure acting on the piston 8 becomes small,
The strokes of all the pistons 8 are increased all at once,
The discharge capacity of the compressor increases infinitely. At this time,
The inclination angle between the drive plate 5 and the oscillating plate 6 increases, and the amplitude of the oscillating motion of the oscillating plate 6 also increases. Figure 1
The pressure in the front housing chamber 1b is minimized, the tilt angle between the drive plate 5 and the rocking plate 6 is maximized, and the stroke of the piston 8 and the discharge capacity of the compressor are maximized. There is.

Since the feature of the present invention resides in the constant speed detent mechanism, FIG. 3 is an enlarged view of only the detent mechanism part in FIG. 1 showing the state of the maximum discharge capacity. Further, FIG. 4 is an enlarged view of only the portion of the rotation stopping mechanism in FIG. 2 showing the state where the discharge capacity is zero.
Note that FIG. 5 is a cross-sectional side view corresponding to the state where the discharge capacity is zero shown in FIG.

As is apparent from these drawings, in the detent mechanism of the illustrated embodiment, even if the rocking plate 6 tries to follow the drive plate 5 and rotate along with the drive plate 5, the tip of the tripod pin 13 is a detent body. Since it engages with the guide groove 1a provided on the inner surface of a certain front housing 1, the rotational movement of the rocking plate 6 is prevented, and only the rocking movement of the rocking plate 6 is allowed. This action is achieved by the three guide grooves 1a provided evenly around the drive shaft 4 and parallel to the drive shaft 4.
Three steel balls 14 that are constantly engaged with each steel ball 1
No. 4 center hole 141 is formed by a rotation-stopping mechanism composed of three evenly arranged pins radially extending from the oscillating plate 6 and slidably engaged, that is, the tripod pin 13. The reciprocating rotary motion of the moving plate 6 is completely blocked and no rotary motion component remains. Therefore, the motion of the oscillating plate 6 becomes a pure oscillating motion, and there is no fear of generating secondary vibration or noise. Further, this detent mechanism does not have a complicated structure near the drive shaft 4 and the swing plate 6, and the tripod pin 13 may be short,
The structure is simple and small, and a compressor including it can be manufactured at low cost.

In the illustrated embodiment, in order to construct a rotation stopping mechanism having a constant velocity for preventing the rotation of the rocking plate 6,
The cross section of the guide groove 1a is circular, while the steel ball 14
Is slidably engaged, and the tip of the tripod pin 13 having a circular cross section is rotatably and slidably inserted into the circular center hole 141 of the steel ball 14. However, the present invention is limited to such an embodiment. The invention is not limited to the above, and various modifications can be made within the technical scope described in the claims.

Another example will be briefly described. For example, each tripod pin can be expanded and contracted in a linear direction.
It has a telescopic structure that is always urged in the extension direction by incorporating a compression spring inside, and at the inner surface of the housing, etc.
Expansion and contraction by providing three linear guide grooves that are evenly arranged in parallel at 20-degree intervals and have a cross-sectional shape that expands slightly in a taper shape. If the tip of the tripod pin is always in contact with the bottom surface of the guide groove and is slid in the linear direction, this mechanism also serves as a detent mechanism having a constant velocity. Play.

Further, in the illustrated embodiment, the pressure in the front housing chamber 1b is changed as a means for changing the discharge angle of the compressor by changing the inclination angles of the drive plate 5 and the oscillating plate 6. However, since the present invention is not characterized by this means,
It goes without saying that other means than the illustrated embodiments which can achieve the same purpose can be adopted.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing a preferred embodiment of an oscillating plate type variable displacement compressor of the present invention.

FIG. 2 is a vertical sectional front view showing another operating state of the embodiment shown in FIG.

FIG. 3 is a vertical sectional front view showing an enlarged main part of FIG.

FIG. 4 is a vertical sectional front view showing an enlarged main part of FIG.

5 is a cross-sectional side view taken along the line AA shown in FIG.

[Explanation of symbols]

1 ... Front housing 1a ... Guide groove 1b ... Front housing room 4 ... Drive shaft 5 ... Drive plate 6 ... rocking plate 7 ... Piston rod 8 ... Piston 13 ... Pin (Tripod pin) 14 ... Steel ball 15 ... Sleeve 21 ... Cylinder bore

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shigeru Kamiya             1-1, Showa-cho, Kariya city, Aichi stock market             Inside the company DENSO (72) Inventor Masafumi Inoue             1-1, Showa-cho, Kariya city, Aichi stock market             Inside the company DENSO (72) Inventor Shigehide Kimura             14 Iwatani Shimohakaku-cho, Nishio-shi, Aichi Stock Association             Company Japan Auto Parts Research Institute F term (reference) 3H076 AA06 BB01 CC20 CC32 CC39                       CC46

Claims (4)

[Claims] 1. A drive shaft which is supported by a housing through a bearing to receive rotational power from a power source, and a drive plate which is connected to the drive shaft and is rotatable and tiltable with respect to the drive shaft. , A rocking plate which has the same inclination angle but is prevented from rotating by being supported by the drive plate through a bearing, and a fluid which is connected to the rocking plate and reciprocates and is inserted into the cylinder bore. A piston for inhaling and compressing the same, three pins radially extending from the peripheral portion of the rocking plate at intervals of 120 degrees to prevent rotation of the rocking plate, and integrally with the housing. Provided parallel to the drive axis and evenly spaced around each other 120
An oscillating plate type variable displacement compressor, characterized in that the oscillating plate type variable displacement compressor is provided with three degrees of positional relationship and is provided with three guide grooves that are constantly engaged with the tips of the three pins. 2. The guide groove according to claim 1, wherein each of the three guide grooves has a circular cross section, and the steel balls are always engaged with the guide grooves and pass through the center of the steel ball. The cross-sectional shape of the center hole is circular, the tips of the three pins are cylindrical, and the tips of the three pins rotate with respect to the center holes of the three steel balls. And the tip of the three pins are always engaged with the three guide grooves by being slidably inserted in the direction of the center hole, respectively. Capacity compressor. 3. The three pins according to claim 1, wherein the three pins are expandable and contractable in the direction of their respective central axes and are always biased in the extension direction, so that the tips of the three pins are always the An oscillating plate type variable displacement compressor, which is engaged with each of three guide grooves. 4. The oscillating plate type variable displacement compressor according to claim 1, wherein the three pins are directly engaged with a member forming the oscillating plate.