JPH07293435A - Variable displacement compressor - Google Patents

Abstract

PURPOSE:To reduce axial length and size by fitting an end of a driving member to an opening formed on a center of a socket plate, and connecting the end of the driving member to the socket plate by means of the connecting pin. CONSTITUTION:An opening 16a is formed to a center of a socket plate 16. An end of a driving member 11a in the opening 16a. An end of the driving member 11a is connected to the socket plate 16 by memans of a connecting pin 11b. The driving member 11 fixed to the end of the driving shaft 11 and the socket plate 16 is one-point supported under the state of being hung from the connecting pin 11b. The socket plate 16 is oscillated around the connecting pin 11b by the operation of a control valve for adjusting a piston stroke. Spacing hardly exists between the socket plate 16 and the driving member 11a, thus reducing axial length of a compressor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a variable displacement compressor capable of varying a discharge amount, and more particularly to a compact variable displacement compressor having a reduced axial length.

[0002]

2. Description of the Related Art Recently, a variable capacity compressor used in an air conditioner for a vehicle is discharged by changing the volume of a compression chamber in a cylinder according to the suction pressure of a refrigerant returned to the compressor. The amount of refrigerant is adjusted so that the suction pressure of the compressor becomes constant. When the suction pressure is kept constant, the refrigerant pressure at the outlet of the evaporator (that is, the evaporation pressure of the refrigerant in the evaporator) becomes constant to some extent, so that it is possible to avoid so-called freezing of the evaporator at the time of low load, and the compressor is exposed to heat load. The discharge amount will be in accordance with the above, and it is possible to reduce the on / off state of the compressor by the clutch part that has been done conventionally, and the rapid temperature change of the blown air and the abrupt rotation of the engine due to the on / off state of the compressor. There is no significant torque change, and comfort during driving can be improved.

This variable displacement compressor is shown in FIG.
There is one shown in 6. The one shown in FIG. 5 has a drive shaft 11 which is rotationally driven by an engine via a belt, a pulley 2 and a clutch portion 2a. A drive member 11a is projectingly provided on the drive shaft 11, and a drive swash plate 13 is connected to the drive shaft 11 via a connecting pin 11b. A non-rotating socket plate 16 is slidably attached to the drive swash plate 13 via a thrust bearing 14 and a radial bearing 15. The socket plate 16 is slidably connected to a guide rod 18 in the casing 17 via a shoe or the like. The guide rod 18 prevents rotation and allows reciprocal movement in the axial direction. A plurality of piston rods 22 are attached to the socket plate 16 at equal intervals in the circumferential direction, and the piston 2 is attached to the other end of the piston rod 22.
3 are connected. When the drive swash plate 13 rotates, the socket plate 16 performs a so-called rasping operation, and the piston 23 is reciprocated in the cylinder chamber 26 of the cylinder block 25 via the piston rod 22 to cause the piston 2 to move.
The front side portion of 3 serves as a compression chamber. The rear side portion of the piston 23 communicates with the crank chamber 12.

The cylinder head 30 has a suction port 29.
And a discharge port 33 are provided, and the return refrigerant from the evaporator flows into the suction port 29, and the refrigerant flows from a suction valve (not shown) that closes the suction port 27 opened in the valve plate 20. It is adapted to flow into the compression chamber formed in the cylinder chamber 26 during the suction process of the piston 23 against the closing elastic force.

Further, the variable displacement compressor controls the amount of the refrigerant discharged from the compressor by changing it according to the suction pressure of the returning refrigerant so that the suction pressure of the compressor becomes constant. have. The control of the control valve Cv is well known as described in, for example, Japanese Utility Model Laid-Open No. 5-10,788.

Further, the one shown in FIG. 6 (clutch part omitted) is one in which the spherical portion 16b provided at the end of the socket plate 16 and the piston 23 are connected via the shoe 19, but FIG. Since the structure is substantially the same as that shown in (1), the same members are designated by the same reference numerals and the description thereof will be omitted.

[0007]

However, in these conventional variable displacement compressors, the position of the connecting pin 11b on the side of the drive member 11a protruding from the drive shaft 11 (hereinafter abbreviated as pin position) and the socket plate 16 are different. Since the position where the end of the piston rod 22 abuts (hereinafter abbreviated as piston connecting position) is separated, this separation length L affects the axial length of the compressor, and the variable displacement compressor axial length is increased. There is a problem that the size of the whole becomes large.

In the former case shown in FIG. 5, the lower end of the socket plate 16 is connected to the guide rod 18 so that the socket plate 16 can smoothly slide in the axial direction without rotating. The drive swash plate 13 and the drive member 11a are fitted in the elongated hole 11c in order to smoothly perform the vertical displacement.

However, by forming the long hole 11c in this way,
In order to smoothly perform the vertical displacement of the socket plate 16, it is preferable to separate the position of the connecting pin 11b from the piston connecting position.

In the latter case where the socket plate 16 is directly connected to the piston 23, the links 16d and 11d protruding from both the driving member 11a and the socket plate 16 are used.
Are connected by a connecting pin 11b because it is considered that the socket plate 16 can be swung smoothly when the two links are connected by pins.

In any case, since the pin position and the piston connecting position are separated from each other, the separation length L increases the length in the axial direction of the compressor and hinders the request for compactness.

The present invention has been made in view of the above-mentioned drawbacks and problems of the prior art, and an object thereof is to provide a compact variable displacement compressor having a reduced axial length.

[0013]

In order to achieve the above object, a variable capacity compressor according to the present invention is provided with a plurality of cylinder chambers in a casing and pistons slidably provided in these cylinder chambers. And a crank chamber formed so as to communicate with these cylinder chambers, and a drive shaft inserted through the crank chamber, and each piston has a piston head fitted to the front end side and a piston head fitted to the rear end side. A recess is formed, and shoes fitted to both inner surfaces of the fitting recess support the socket plate so as to be tiltable with respect to the drive shaft so as to be swingable, and are pin-connected to a drive member rotated by the drive shaft. In the variable capacity compressor, the inclination state of the socket plate is adjusted by a control valve that adjusts the internal pressure of the crank chamber. The end portion of the drive member is fitted in the opening provided at substantially the center of the racket plate, and the end portion of the drive member and the socket plate are connected and supported by one connecting pin. Characterize.

The socket plate is pin-connected to a support ring which is provided in the opening and through which the drive shaft is inserted, and the inclination angle of the support ring is not perpendicular to the drive shaft on the drive shaft. It is characterized by being held by a spring.

The connecting pin is located on a center line of the socket plate that passes through an intersection of the pin axis connecting the socket plate and the support ring with the axis line of the drive shaft and a supporting position of the socket plate by the shoe. It is characterized in that it is provided to do.

[0016]

According to the first aspect of the present invention, the tip end of the drive member, the base end of which is fixed to the drive shaft, and the top end of the socket plate are suspended by one connecting pin, that is, the socket plate is, so to speak. Since it is supported at one point, when the control valve operates, the socket plate swings around the connecting pin to adjust the stroke of the piston. In this case, there is almost no separation length between the socket plate and the drive member, and the axial length of the compressor can be shortened accordingly.

According to a second aspect of the present invention, when the socket plate is connected to the support ring and the support ring is held by the spring so that the inclination angle is not perpendicular to the drive shaft, the pin position is maintained. If the piston connecting position is not separated from the piston connecting position, the length of this spring may be a short one, which simplifies the construction.

According to a third aspect of the present invention, the position of the connecting pin passes through the axis of the pin connecting the socket plate and the support ring and the intersection of the axis of the drive shaft and the supporting position of the socket plate by the shoe. The piston stroke can be adjusted by locating the socket plate on the center line of the socket plate.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a variable displacement compressor according to an embodiment of the present invention, and FIG. 2 shows a main part of FIG.
2 is an arrow view taken along line -2, FIG. 3 is a skeleton diagram showing a main part of the same embodiment, and FIG. 4 is a skeleton diagram showing a main part of the configuration of the conventional example. Are given the same reference numerals.

The variable capacity compressor of this embodiment shown in FIG. 1 is a cylinder block 25 which is a part of a casing 17 in which a cylinder chamber 26 and a crank chamber 12 are formed.
A cylinder head 30 provided at the end of the casing 17 via a valve seat 20; and a clutch portion 2a attached to the protruding end of the drive shaft 11 provided through the casing 17. Have

The clutch portion 2a selectively transmits the rotation of the engine to the drive shaft 11 via the belt and the pulley 2.

A plurality of cylinder chambers 26 are provided in the Linda block 25 at equal intervals in the circumferential direction, and pistons 23 are installed in each of the cylinder chambers 26. Each of these pistons 23 has a piston head 23a on the front end side and a fitting recess 23b on the rear end side.
The shoes 19 are rotatably fitted on the inner surfaces 23c on both sides of the fitting recess 23b, and the front and back flat surfaces of the socket plate 16 are sandwiched between these shoes 19.

Particularly, in this embodiment, as shown in FIG.
An opening 16a is provided in the center of the socket plate 16, and an end of the driving member 11a is fitted in the opening 16a. The end of the driving member 11a is connected to the socket plate 16 by a connecting pin 11b. There is. That is, the socket plate 16 is provided by the connecting pin 11b provided at the tip of the drive member 11a whose base end is fixed to the drive shaft 11.
The upper end of the is suspended. Therefore,
Since the end of the socket plate 16 and the tip of the drive member 11a are, so to speak, supported at one point in the fitting recess 23b of the piston 23 by one connecting pin 11b, the socket plate 16 and the drive member 11a are not supported. The above-described separation length L does not exist between them, and the axial length of the compressor can be shortened accordingly.

The position where the connecting pin 11b is provided does not necessarily have to be the upper end of the socket plate 16, and as shown in FIG. 1, the axis of the pin 31a connecting the socket plate 16 and the supporting ring 31 and the drive line. It may be provided so as to be located on the center line of the socket plate 16 that passes through the intersection of the axis of the shaft 11 and the supporting position of the socket plate 16 by the shoe 19.

However, if the connecting pin 11b is provided on the central axis other than the upper end of the socket plate 16, for example, when the connecting pin 11b is at the position shown by the broken line in FIG. The stroke S2 is shorter than the stroke S1 when the connecting pin 11b is provided at the upper end of the socket plate 16 by x. Therefore, the connecting pin 11b is attached to the socket plate 1
When it is provided on the central axis other than the upper end of 6, it is necessary to set the size of the piston, the cylinder or the like in consideration of the reduction of the stroke, but rather this is used to adjust the stroke of the piston. You can also
When the inclination of the socket plate 16 is close to a right angle with respect to the drive shaft 11, the top dead center and the valve plate 20 can be widened.

Further, in this variable displacement compressor,
As is well known, when the pressure in the crank chamber 12 increases,
The socket plate 16 is perpendicular to the drive shaft 11.
However, in this state, the refrigerant is not discharged and the pressure difference before and after the piston 23 disappears, and in this state,
Once again, the compressor cannot perform the compression action, and is, as it were, locked. Therefore, the spring 32 holds the socket plate 16 elastically so that the socket plate 16 is not completely perpendicular to the drive shaft 11.

Here, the socket plate 16 is also connected to a pin 31a of a support ring 31 provided in the opening 16a and configured so that the drive shaft 11 is inserted therethrough. The support ring 31 is a socket. Plate 1
It is held by a spring 32 so that the inclination angle of 6 is not perpendicular to the drive shaft 11. In addition, this spring 32
Is composed of a spring 32a between the support ring 31 and a flange 34 provided on the drive shaft 11, and a spring 32b between the support ring 31 and the drive member 11a. Also in this spring 32, if the above-mentioned separation length L is small, there is an advantage that the spring can be made shorter and the structure can be simplified.

The tip of the drive shaft 11 is fitted in the center hole 36 of the cylinder block 25 and is rotatably supported by a bearing 37, and the rear end of the drive shaft 11 is on the casing 1 side.
Similarly, it is rotatably supported by bearings 38 and the like provided on the casing 7. The projecting end portion of the casing 17 is connected to the clutch portion 2a.

The cylinder head 30 is provided with a suction port 29 and a discharge port 33. The suction port 2
Returning refrigerant from the evaporator flows into 9 and this refrigerant resists the closing resilience of the suction valve that closes the suction port 27 opened in the valve plate 20 and enters the cylinder chamber 26 in the suction process. It is adapted to flow into the compression chamber formed.

In this variable displacement compressor, a control valve Cv is provided in the cylinder head 30, and the pressure in the crank chamber is adjusted according to the suction pressure of the returning refrigerant to change the angle of the socket plate. The amount of refrigerant discharged from the compressor is adjusted to control the suction pressure of the compressor to be constant.

Next, the operation of this embodiment will be described. When the heat load in the cooling cycle is small, the suction pressure Ps
Low return gas refrigerant is guided to the control valve Cv, and by the control of the control valve Cv, a part of the refrigerant having a high discharge pressure Pd compressed by the piston 23 is introduced into the crank chamber 12 to increase the crank chamber pressure Pc. A pressure difference occurs before and after the piston 23. As a result, a moment of force from each piston acts on the socket plate 16, and the socket plate 16 also tilts around the connecting pin 11b at a right angle to the drive shaft so as to make a sufficiently large stroke corresponding to this. In this state, when the drive shaft 11 is rotationally driven by the engine via the belt, the pulley 2 and the clutch portion 2a, the drive member 11a attached to the drive shaft 11 also rotates, and via this the connecting pin 11b. The connected socket plates 16 rotate in a rasping manner.

As a result, the piston 23 moves in the cylinder chamber 2
Although it reciprocates within 6, it does not make a full stroke but compresses with a small stroke, the amount of refrigerant compression is small, and the amount of refrigerant is appropriate according to a low heat load.

On the other hand, when the heat load in the cooling cycle is large, the return refrigerant having a high suction pressure Ps is guided to the control valve Cv, and the suction pressure Ps is introduced into the crank chamber 12 by the control of the control valve Cv. As a result, the pressure in the crank chamber 12 drops and the piston 23
The differential pressure before and after is reduced. As a result, the piston 23 is easily displaced, and the socket plate 16
The socket plate 16 is inclined with respect to the drive shaft 11 by the action of a moment with the connecting pin 11b as a fulcrum, and the reciprocating stroke of the piston 23 becomes longer. If compressed in this state, the amount of discharged refrigerant increases, the refrigerant flow rate becomes appropriate according to a high heat load, and the suction pressure Ps of the compressor gradually decreases, and as a result, the suction pressure Ps is kept constant. .

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the claims. For example, in the embodiment described above,
Although the variable displacement compressor having the clutch portion 2a has been described, the present invention does not necessarily have to include the clutch portion 2a and can be applied to a so-called clutchless compressor.

[0035]

As described above, according to the present invention, the end portion of the drive member is fitted in the opening provided at the substantially central portion of the socket plate, and the end portion of the drive member and the socket plate are attached. Since it is configured to be connected and supported by one connecting pin, the pin position and the piston connecting position are not separated from each other, and the axial length of the compressor can be shortened by that much, resulting in a compact compressor. For example,
As will be more apparent when compared with the conventional variable displacement compressor shown in FIG. 4, the separation length between the pin position and the piston connecting position is shortened by 10 to 30%.

Also, the socket plate is connected to a support ring, and the support ring is held by a spring on the drive shaft so that the inclination angle is not perpendicular to the drive shaft, but the pin position and the piston connection position are separated from each other. If this is not done, the length of this spring may be short, and the construction becomes that simple.

Further, the position of the connecting pin is located on the center line of the socket plate that passes through the intersection of the axis of the pin connecting the socket plate and the support ring with the axis of the drive shaft and the position where the shoe supports the socket plate. By doing so, the stroke of the piston can be adjusted.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is a view taken along line 2-2 of FIG.

FIG. 3 is a skeleton diagram showing a main part of the embodiment.

FIG. 4 is a skeleton diagram showing a main part of a conventional compressor.

FIG. 5 is a sectional view showing an example of a conventional compressor.

FIG. 6 is a sectional view showing another example of a conventional compressor.

[Explanation of symbols]

11 ... Drive shaft, 11a ... Drive member,
11b ... connecting pin, 12 ... crank chamber,
16 ... Socket plate, 16a ... Opening, 1
7 ... Casing, 19 ... Shoe, 23 ...
Piston, 23a ... Piston head,
23b ... Fitting concave portion, 23c ... Inner side surface, 2
6 ... Cylinder chamber, 31 ... Support ring, 3
1a ... pin, 32 ... spring, Cv ... control valve.

Claims (3)

[Claims] 1. A plurality of cylinder chambers are provided in a casing (17).
(26), a piston (23) slidably provided in each of these cylinder chambers, a crank chamber (12) formed so as to communicate with these cylinder chambers (26), and this crank chamber (12) Each piston (23) has a piston head (23a) on the front end side and a fitting recess (23b) on the rear end side. Inner side surfaces of recess (23b)
Socket plate with shoe (19) fitted in (23c)
A drive member (1) that supports the (16) so as to be tiltable with respect to the drive shaft (11) and can be rotated by the drive shaft (11).
1a) and a connecting pin (11b), and a variable capacity compressor that adjusts the inclination state of the socket plate (16) by a control valve (Cv) that adjusts the internal pressure of the crank chamber (12). In, the end portion of the drive member (11a) is fitted into the opening (16a) provided at substantially the center of the socket plate (16), and the drive member (1
A variable capacity compressor characterized in that the end of (1a) and the socket plate (16) are connected and supported by one connecting pin (11b). 2. The socket plate (16) is connected to a support ring (31), which is provided in the opening (16a) and through which the drive shaft (11) is inserted, by a pin (31a), and supports the support ring (31). The inclination angle of the ring (31) on the drive shaft (11) is
The variable displacement compressor according to claim 1, wherein the variable displacement compressor is held by a spring (32) so as not to be perpendicular to (1). 3. The connecting pin (11b) is a pin (31) for connecting the socket plate (16) and the support ring (31).
It is provided so as to be located on the center line of the socket plate that passes through the intersection of the axis of (a) and the axis of the drive shaft (11) and the supporting position of the socket plate (16) by the shoe (19). The variable capacity compressor according to claim 2.