JPH0454833B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable displacement compressor, and particularly to a rotating cylinder type swash plate type variable displacement compressor suitable for use in vehicle air conditioners and the like.

[Conventional technology]

Compressors used in automotive air conditioners, etc. are driven directly by the engine, so they can be used over a wide range of rotational speeds, and their refrigeration capacity also fluctuates greatly in response to changes in heat load between summer and winter. In order to always perform efficient operation in response to these conditions, it is necessary to make the compressor capacity variable.

By the way, conventionally, for example,
As disclosed in the publication, a drive plate having a cam function is provided on the drive shaft of the compressor, a swash plate equipped with a piston connecting member is provided on one side of the drive plate, and the drive plate is oscillated and rotated. A so-called fixed-cylinder swash plate type variable capacity compressor, in which the swash plate and the piston connecting member are axially swung to move the piston of the compressor and thus operate the compressor, is disclosed in Japanese Patent Publication No. 57-43744. To be,
While fixing the cylinder head (fixed distribution plate) with suction port and discharge port, the cylinder, piston,
A so-called rotary cylinder type in which the piston support member is rotated together with the drive shaft, and this piston support member is supported relative to a swash plate that performs tilting operation (inclination angle control), thereby causing the piston to reciprocate while rotating the cylinder. A swash plate type variable displacement pump is known.

[Problem to be solved by the invention]

Among these, the former type of fixed cylinder swash plate type variable displacement compressor is widely used as an air conditioning compressor, but because the piston reciprocates within the fixed cylinder, the suction port of the cylinder head is As a result, the passage resistance of the suction port becomes relatively large, making it difficult to obtain the high volumetric efficiency of a rotary compressor.

In addition, in order for the drive plate (cam mechanism) that reciprocates the swash plate and the piston to rotate while swinging together with the drive shaft of the compressor, it is preferable to mechanically couple the drive plate and the tilt angle control mechanism. Conventionally, the inclination angles of the swash plate and drive plate have been controlled exclusively by controlling the internal pressure of the compressor using complicated control means.

On the other hand, the latter type of rotating cylinder system can deal with the above problems, but since the piston support member contacts the swash plate through the shoe, the shoe slides directly on the swash plate surface, so this is difficult. This is a cause of friction loss in rotational force, and consideration must be given to always keep the piston top dead center position constant despite changes in piston stroke, even though the piston stroke can be variably adjusted by tilting the swash plate and eventually the piston support member. Because the dead volume could not be kept small, it was unsuitable for use as a gas compressor.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of a rotary cylinder type rotary machine and to realize a rotary cylinder type swash plate type variable capacity compressor with excellent performance.

[Problem to be solved by the invention]

In order to achieve the above object, the present invention basically proposes the following problem-solving means. In order to facilitate understanding of the invention, the gist of the invention will be explained by quoting the reference numerals of the embodiments used in FIG.

That is, the present invention provides a drive shaft 2 rotatably supported within a housing 1 serving as the main body of the compressor.
A cylinder block 17 having a plurality of cylinder bores 18 arranged in the circumferential direction is rotatably attached to the drive shaft 2, and one end of the cylinder block 17 is connected to a suction port 14 fixedly disposed within the housing 1. A swash plate 27 and a piston support plate 21 are arranged in the inner space of the housing, which is covered with airtightness by the cylinder head 13 with a discharge port 15, and faces the side of the cylinder block 17 opposite to the cylinder head 13. When the force of the inclination angle control mechanism 35 is applied to the point of application, the swash plate 27 moves into a cam groove 28 located at one end thereof and a fulcrum pin 29 that engages with the cam groove 28.
(One of the cam grooves 28 and the fulcrum pin 29 is fixed in the swash plate 27 and the other in the housing 1.) The drive shaft 2 is tilted as the center of the swash plate moves in the axial direction. On the other hand, the piston support plate 21 is supported on one surface of the swash plate 27 via a thrust bearing 32 so as to be rotatable relative to the swash plate 27, and has directivity in the direction of tilting of the swash plate 27. The constant velocity ball joint 22 is connected to the drive shaft 2 via a speed ball joint 22 so as to be able to rotate integrally with the drive shaft, and the constant velocity ball joint 22 has a shaft mounting structure that allows movement in the axial direction of the drive shaft 2. The piston support plate 21 and the swash plate 27 constitute a mechanism that tilts with the axial movement of the piston support center, and the piston support plate 21 and the piston 19 housed in the cylinder bore 18 connect the connecting member 40 connected through.

[Effect]

With such a configuration, rotation of the drive shaft 2 causes the cylinder block 17 (cylinder bore 18),
The piston 19, constant velocity ball joint 22, and piston support plate 21 rotate together with the drive shaft 2.

On the other hand, the swash plate 27, which is in a non-rotating state in the radial direction, is tilted (tilting operation) by the power of the tilt angle control mechanism 35 and its tilt angle is controlled.
This tilting is accompanied by movement of the center portion of the swash plate along the axis of the drive shaft 2 due to cooperation between the cam groove 28 and the fulcrum pin 29 that engages with the cam groove 28 . In response to this movement, the piston support plate 21 also tilts on the constant velocity ball joint 22, with the center thereof moving in the axial direction together with the constant velocity ball joint 22.

As a result, the piston support plate 21 rotates at the same speed as the cylinder bore 18 on the swash plate 27 surface with a controlled inclination angle, and the piston 19 performs suction, compression, and discharge operations at a predetermined rotational position.

Even if the inclination angle θ of the swash plate 27 and the piston support plate 21 changes during the piston operation accompanied by this rotation, and the piston stroke changes, the tilting of the swash plate 27 and the piston support plate 21 will not move in the axial direction of their centers. By the movement of the swash plate 27, the cam groove 28 at one end of the swash plate 27, and the cam movement of the fulcrum pin 29, the piston top dead center position is always kept constant (a minute dead volume can be maintained), and as a result, the rotary cylinder type variable displacement compression It can perform the gas compression function as a machine. Furthermore, the piston support plate 21 can be rotated at high speed by reducing friction loss by the thrust bearing 32 on the swash plate 27, so that the performance of the compressor can be improved.

Furthermore, in the case of the rotating cylinder type, the cylinder bore 18 rotates relative to the cylinder head 13, so the rotational displacement of the cylinder bore 18 makes it possible to open and close the suction port without the need for a suction valve. This reduces the passage resistance and increases the volumetric efficiency within the cylinder bore.

Furthermore, since the swash plate 27 itself, which regulates the angle of inclination when the piston support plate 21 rotates, does not rotate in the radial direction, the swash plate and the swash plate tilting mechanism can be mechanically connected easily, and the mechanism can be simplified. obtain.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a longitudinal sectional view showing the maximum piston stroke state of the variable displacement compressor according to this embodiment, Fig. 2 is a sectional view taken along the line X-X of Fig. 1, and Fig. 3 is the minimum piston stroke of this embodiment. It is a partial sectional view showing a state.

In the figure, 1 is a housing of a compressor main body, and a drive shaft 2 is rotatably supported at the center of the housing 1 via two radial bearings 3 and 4. One end of the drive shaft 2 protrudes from the side plate 1a of the housing 1, and the rotational force of the engine is transmitted through the electromagnetic clutch mechanism 5. The electromagnetic clutch mechanism 5 includes a stator 6 installed on the side plate 1a of the housing 1, a rotor 7 that rotates via a V-belt (not shown) as the engine rotates, and an armature attached to the protruding end of the drive shaft 2. 8, the armature 8 is attracted to the rotor 7 by the excitation action of the stator 6, and the armature 8 and the drive shaft 2 are rotated.

9 is a low pressure chamber for introducing fluid such as refrigerant gas into the cylinder bore 18 of cylinder assembly C, which will be described later; 10 is a high pressure chamber for discharging fluid compressed by the operation of the piston 19; The chamber 9 and the high pressure chamber 10 are located on the side plate 1b of the housing 1.
A space A defined in the circumferential direction at the inner end of
Consists of B. A low pressure chamber 9 and a high pressure chamber 10 are formed at positions where these spaces A and B face each other, surrounding the cylinder head 13 and the side plate 1b of the housing 1.

11 is a suction hole for introducing fluid, and 12 is a discharge hole for discharging fluid from the high pressure chamber 10.

The cylinder head 13 is fixedly arranged within the housing 1, and has a suction port 14 without a suction valve on the low pressure chamber 9 side, and a discharge valve 16 on the high pressure chamber 10 side.
A discharge port 15 is provided. 16' is a discharge valve holder.

Reference numeral 17 denotes a cylinder block which together with the cylinder head 13 constitutes a cylinder assembly C. The cylinder block 17 is formed separately from the cylinder head 13, and as shown in FIG. It is attached to the drive shaft 2 so that the One end surface of the cylinder block 17 is covered by the cylinder head 13 while maintaining airtightness. That is, one open end of the cylinder bore 18 is closed by the cylinder head 13 except for the position where the suction port 14 is provided, and
A piston 19 is housed inside each cylinder bore 18, and a compression chamber 20 is formed between the piston 19 and the closed end of the cylinder bore 18. The cylinder head 13 and the cylinder block 17 are in close contact with each other, and the cylinder block 17 rotates and slides relative to the cylinder head 13.

On the other hand, a swash plate 27 and a piston support plate 21 are arranged in the housing interior space on the opposite side of the cylinder head 13 of the cylinder block 17 as follows.

The swash plate 27 is loosely fitted to the drive shaft 2,
A cam groove 28 is provided at one end (upper end) of the back surface. A fulcrum pin 29 that engages with this cam groove 28 is fixedly arranged within the housing 1. Further, the side opposite to the side where the cam groove 28 is provided is used as a point of action and is mechanically connected to a tilt angle control mechanism 35, which will be described later. Furthermore, guide pins 3 are provided on both the left and right sides of the swash plate 27.
A guide pin 30 is movably engaged with a guide groove 31 formed on the inner wall of the housing 1. The guide groove 31 is formed so that its length direction is parallel to the drive shaft 2.

The inclination angle control mechanism 35 includes a moving body (screw tube) 36 held at the lower part of the outer peripheral edge of the swash plate 27 via a holding member 36', a screw rod 37 for moving the moving body 36 in the axial direction, and a compressor. It consists of a gear 39 that transmits the rotational force of a servo motor 38 activated by a control signal from a control circuit (not shown) to a screw rod 37, and when the servo motor 38 rotates according to a capacity control signal of the compressor, the screw The moving body 36 moves forward or backward (arrow D,
E direction) and tilt the swash plate 27 to control its inclination angle.

The piston support plate 21 is supported on one surface of the swash plate 27 via a thrust bearing 32 so as to be rotatable relative to the swash plate 27, and is supported via a constant velocity ball joint 22 having directivity in the direction in which the swash plate 27 tilts. It is connected to the outer peripheral surface of the drive shaft 2 so as to be able to rotate integrally with the drive shaft.

The constant velocity ball joint 22 includes a pair element (inner ring) 22a having a spherical outer peripheral surface, and a pair element 22a.
The paired element 22b, which can rotate on the outer periphery, is engaged via a ball 24 fitted into an axial guide groove provided on the paired element 22a side, and the paired element 22a side is connected to the spline 25. By fitting onto the drive shaft 2 through the shaft, the shaft mounting structure is movable in the axial direction.

With such a mounting structure, the piston support plate 2
The swash plate 1 rotates integrally with the drive shaft 2, and has directivity in the tilting direction of the swash plate 27 due to the sliding action of the ball 24 and the pair element 22b during rotation.
Tilt with 7.

40 is a piston connecting member that connects the piston 19 and the piston support plate 21, and ball portions 41 and 42 provided at both ends of the piston connecting member 40 are connected to the piston 19 and the piston support plate 21 in a spherical pair, respectively. When the piston support plate 21 and cylinder block 17 rotate together with the drive shaft 2, the piston 19 reciprocates within the rotating cylinder bore 18 via the piston connecting member 40.

Since the piston 19 reciprocates in synchronization with the rotation of the cylinder bore 18, strokes such as suction, compression, and discharge are performed at different rotational positions. dead center, i.e.
Stroke motion is performed at 180° intervals. Therefore, the above-mentioned discharge port 15 and suction port 14 are connected to H,
The low pressure chamber 9 is disposed in the cylinder head 13 corresponding to the position L, and further communicates with the suction port 14. As shown in FIG. On the other hand, the high pressure chamber 10 is arranged corresponding to the rotational position of the cylinder bore 18 where the piston 19 performs the discharge stroke.

Reference numeral 43 denotes an O-ring that seals the space in the high pressure chamber 10, and the high pressure gas inside the high pressure chamber 10 acts to press the cylinder head 13 against the sliding surface of the cylinder block 17 and seal it.

Next, the operation of this embodiment will be explained.

When the drive shaft 2 rotates, the cylinder block 17
(cylinder bore 18), piston 19, constant velocity ball joint 22, and piston support plate 21 rotate together with drive shaft 2.

On the other hand, the swash plate 27 is in a non-rotating state in the radial direction of the drive shaft 2, but is tilted by the inclination angle control mechanism 35 when the servo motor 38 is driven based on a signal that controls the discharge capacity of the compressor depending on the situation. The inclination angle θ is controlled.

This tilting is accompanied by movement of the center of the swash plate along the axis of the drive shaft 2 under the guidance of the guide pin 30 and the guide groove 31 due to the cooperation of the cam groove 28 and the fulcrum pin 29 that engages with the cam groove 28 . In response to this movement, the piston support plate 21 also tilts on the constant velocity ball joint 22, with the center thereof moving in the axial direction together with the constant velocity ball joint 22.

As a result, the piston support plate 21 rotates on the swash plate 27 surface at the same speed as the cylinder bore 18 at a controlled inclination angle θ, and the piston 19 performs suction, compression, and discharge operations at a predetermined rotational position.

Even if the inclination angle θ of the swash plate 27 and the piston support plate 21 changes during the piston operation accompanied by this rotation, and the piston stroke changes, the tilting of the swash plate 27 and the piston support plate 21 will not move in the axial direction of their centers. The movement of the cam groove 28 and the movement of the relative engagement point (fulcrum) of the fulcrum pin 29 work together to keep the piston top dead center position constant (keep a minute dead volume), and as a result, the rotating cylinder shape can be changed. It can perform the gas compression function as a capacity compressor.

For example, if the piston support plate 21 is set to the maximum inclination angle via the inclination angle control mechanism 35 and the swash plate 27 as shown in FIG. When 27 is set to the minimum inclination angle (0°), the piston stroke becomes zero, resulting in the minimum discharge capacity (discharge capacity zero), and the tilting of the swash plate 27 and, by extension, the piston support plate 21 can be controlled within this maximum to minimum inclination angle range. in,
Variable capacity control according to heat load becomes possible.

In addition, in such rotary cylinder compression, the cylinder bore 18 rotates relative to the cylinder head 13, so the rotational displacement of the cylinder bore 18 eliminates the need for a suction valve and the suction port 14 is rotated.
The suction port 14 can be opened and closed, and there are no obstacles in the suction port 14, thereby reducing the passage resistance and increasing the volumetric efficiency within the cylinder bore (compression chamber 20).

Since the swash plate 27 itself, which regulates the angle of inclination during rotation of the piston support plate 21, does not rotate in the radial direction, the swash plate and the swash plate tilting mechanism can be mechanically connected easily, and the mechanism can be simplified.

Furthermore, according to this embodiment, the capacity of the compressor can be reduced to zero by controlling the stroke of the piston without disengaging the electromagnetic clutch mechanism 5, so there is no need to frequently turn on and off the electromagnetic clutch mechanism, resulting in improved durability. It is possible to improve the

The inclination angle control mechanism 35 of this embodiment uses a reciprocating mechanism that utilizes the screw action of the threaded cylinder 36, but instead of this, an appropriate reciprocating mechanism such as a fluid actuator or a reciprocating mechanism such as a fluid actuator or the like may be used. The inclination angle of the swash plate may be controlled by pressure control.

〔Effect of the invention〕

As described above, according to the present invention, the problem of not being able to keep the dead volume of the conventional rotary cylinder type rotary machine small and the problem of wear loss during rotation of the piston support plate can be solved, and Utilizing the advantage of the rotating cylinder type (reducing ventilation resistance at the suction port), it is possible to provide a rotating cylinder type swash plate type variable capacity compressor with excellent performance.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, FIG. 2 is a sectional view taken along the line X-X in FIG. 1, and FIG. 3 is a sectional view of essential parts during minimum capacity control of the compressor in the above embodiment. It is. DESCRIPTION OF SYMBOLS 1... Housing, 2... Drive shaft, 5... Electromagnetic clutch, 9... Low pressure chamber, 10... High pressure chamber, 11
... Suction hole, 12 ... Discharge hole, 13 ... Cylinder head, 14 ... Suction port, 15 ... Discharge port, 16 ... Discharge valve, 17 ... Cylinder block, 18 ... Cylinder bore, 19 ... Piston ,
20... Compression chamber, 21... Piston support plate, 22
... Constant velocity ball joint, 25 ... Spline, 27 ... Swash plate, 30 ... Guide pin, 35 ...
...Inclination angle control mechanism, 40...Piston connection member.

Claims (1)

[Scope of Claims] 1. A cylinder block 17 in which a plurality of cylinder bores 18 are arranged in the circumferential direction is attached to a drive shaft 2 rotatably supported within a housing 1 serving as the main body of the compressor. The cylinder block 17 is integrally rotatably mounted, and one end of the cylinder block 17 is covered in an airtight manner by a cylinder head 13 with a suction port 14 and a discharge port 15 fixedly arranged in the housing 1. A swash plate 27 and a piston support plate 21 are disposed in the inner space of the housing facing the surface opposite to the head 13. Of these, the swash plate 27 is configured such that when the force of the tilt angle control mechanism 35 is applied to the point of application, the swash plate 27 A cam groove 28 located on one end side and a fulcrum pin 29 that engages with the cam groove 28
(One of the cam grooves 28 and the fulcrum pin 29 is fixed in the swash plate 27 and the other in the housing 1.) The drive shaft 2 is tilted as the center of the swash plate moves in the axial direction. On the other hand, the piston support plate 21 is supported on one surface of the swash plate 27 via a thrust bearing 32 so as to be rotatable relative to the swash plate 27, and has directivity in the direction of tilting of the swash plate 27. The constant velocity ball joint 22 is connected to the drive shaft 2 via a speed ball joint 22 so as to be able to rotate integrally with the drive shaft, and the constant velocity ball joint 22 has a shaft mounting structure that is movable in the axial direction of the drive shaft 2. The piston support plate 21 and the swash plate 27 constitute a mechanism that tilts with the axial movement of the center of the piston support plate, and the piston support plate 21 and the piston 19 housed in the cylinder bore 18 are connected to a connecting member 40 A rotary cylinder type variable capacity compressor characterized by being connected via a rotary cylinder type variable capacity compressor.