JPH073233B2 - Variable capacity vane rotary compressor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a variable capacity vane rotary compressor used as a refrigerant compressor of an air conditioner for automobiles, for example.

(Prior Art) Generally, in a vane type rotary compressor, in order to variably control the discharge amount, a suction port that opens into the cam ring is provided on a side plate that seals one end of the cam ring, and the opening position is on the cam surface. By moving along, the compression start position of the vane is changed to control the discharge amount.

As a conventional variable capacity vane type rotary compressor of this type,
For example, it is known that a front plate is provided with an arc-shaped bypass port that opens in substantially the entire area of the working chamber, and a movable plate having an arc-shaped bypass opening is provided between the front plate and the cam ring. In this structure, the discharge amount is variably controlled by rotating the movable plate by a piston-cylinder type actuator provided in the compressor to change the position of the bypass opening.

(Problems to be Solved by the Invention) However, in such a conventional variable displacement vane type rotary compressor, the actuator includes a cylinder and a piston slidably inserted in the cylinder,
The control pressure is introduced into the cylinder, and the piston is operated against the urging force of the spring interposed between the bottom of the cylinder and the piston to rotate the movable plate. Therefore, the reaction force of the spring changes depending on the stroke position of the piston, and it is difficult to make the response and stability of the discharge amount control of the compressor uniform throughout the stroke of the piston. there were. Further, in order to solve the above problems, if the spring constant of the spring is reduced to reduce the change in the spring reaction force, the coil diameter of the spring and the number of coil turns increase, and the shape of the spring increases. There is also a problem that the size of the compressor increases, and the size of the compressor itself increases accordingly.

(Object of the Invention) Therefore, the present invention provides a piston of an actuator with a small diameter portion,
Forming a large diameter portion and a medium diameter portion to define a first cylinder chamber, a second cylinder chamber and a third cylinder chamber in the cylinder,
The suction pressure of the compressor is supplied to the first cylinder chamber, the control pressure is supplied to the second cylinder chamber via the control valve, and the pressure lower than the suction pressure is supplied to the third cylinder chamber. The object is to make the reaction force acting on the piston constant, to make the response and stability of the discharge amount control of the compressor uniform, and also to make the compressor compact.

(Means for Solving the Problems) In order to achieve the above object, the variable capacity vane type rotary compressor according to the present invention has a cam ring having a cam surface formed on the inner periphery thereof, and a plurality of suction ports formed therein. A front plate provided on the front side, a rear plate that seals the rear side opening of the cam ring, a rotor that is located between the front plate and the rear plate, and is rotatably housed in the cam ring, and a cam ring. A plurality of working chambers formed between the rotors, a plurality of vanes that are inserted into and retracted from the rotor and are in sliding contact with the cam surface at the tip end, the cam ring,
A cylindrical housing with a bottom, which houses a front plate, a rear plate, a rotor, and a vane, a head cover that seals an open end of the housing, an intake chamber defined by the head cover and the front plate, and the cam ring. , A plurality of openings which are communicated with the suction chamber via the suction port of the front plate and which are opened to the cam surface so as to be cut off from the communication with the working chamber when the volume of the working chamber divided by the vane is maximized. Intake port and a bypass port that is formed in the front plate and that opens into the working chamber along the cam surface and communicates with the intake chamber, and is rotatably provided between the front plate and the cam ring to adjust the opening degree of the bypass port. A movable plate having a bypass opening for adjusting and an actuator for rotating the movable plate are provided, and the actuator is controlled. In a variable displacement vane type rotary compressor that changes the discharge amount of the compressor by operating in accordance with the control pressure, the actuator is slidably inserted into the cylinder and the cylinder to rotate the movable plate. A piston, a small diameter portion, a large diameter portion having an outer periphery slidingly contacting the cylinder, and a medium diameter portion having an outer periphery slidingly contacting the cylinder are sequentially formed in the axial direction of the piston to form a cylinder, a small diameter portion and a large diameter portion. The suction pressure of the compressor is supplied to the first cylinder chamber defined by the compressor, and the control pressure is supplied from the compressor to the second cylinder chamber defined by the cylinder, the large diameter portion and the medium diameter portion via the control valve. Along with
A pressure lower than the suction pressure is supplied to the third cylinder chamber defined by the cylinder and the medium diameter portion.

(Operation) In the present invention, the piston of the actuator is formed with the small diameter portion, the large diameter portion and the medium diameter portion to define the first cylinder chamber, the second cylinder chamber and the third cylinder chamber in the cylinder.
A suction pressure of the compressor is supplied to the first cylinder chamber, a control pressure is supplied to the second cylinder chamber via a control valve, and a pressure lower than the suction pressure is supplied to the third cylinder chamber. Then, the reaction force acting on the piston becomes constant over the entire stroke of the piston. Therefore, the response and stability of the discharge amount control of the compressor are made uniform, and the compressor is also downsized.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

1 to 3 are views showing an embodiment of the present invention.

In FIGS. 1 and 2, reference numeral 1 is a cylindrical cam ring, and a cam surface 1a having a substantially elliptical cross section is formed on the inner circumference. A front plate 2 is attached to an opening end of the cam ring 1 on the front side (left side in FIG. 1), and a rear side (right side in FIG. 1).
A rear plate 3 is attached to the open end of the cam ring 1 to seal the opening of the cam ring 1. A cylindrical rotor 4 is provided in the cam ring 1 between the float plate 2 and the rear plate 3.
Is rotatably accommodated, and a plurality of vanes 5 are fitted into the rotor 4 so that the vanes 5 can slide in and out so as to come into sliding contact with the cam surface 1a at the tip. The cam ring 1, the front plate 2, the rear plate 3, the rotor 4, and the vane 5 are housed in a cylindrical housing 6 having a bottom, and the housing 6 has an opening at an opening end on the front side (left end in FIG. 1). A head cover 7 for sealing is attached by a bolt (not shown).

Reference numeral 10 denotes a pair of working chambers formed between the cam ring 1 and the rotor 4, and a pair of suction ports 11 opened to the cam surface 1a.
Is in communication with. These suction ports 11 have the maximum volume of the working chamber 10 divided by the vane 5,
It is provided so that communication with the working chamber 10 is cut off.
Further, the intake port 11 includes a plurality of holes 11a opened in the cam surface 1a of the cam ring 1 and a hole 11b communicating with an intake chamber 14 described later through an intake port 16 (see FIG. 2) formed in the front plate 2. Become. A pair of discharge ports 12 formed in the cam ring 1 are opened at the position of the end of the working chamber 10 (the end in the clockwise direction in FIG. 2), and the housing 6 is inserted through a discharge valve provided in the discharge port 12. The discharge chamber 13 and the working chamber 10 therein communicate with each other. Reference numeral 14 denotes a suction chamber defined by the front plate 2 and the head cover 7, into which a refrigerant gas is introduced from an inflow port 15 provided in the head cover 7, and through a suction port 16 and a suction port 11 formed in the cam ring 1. Refrigerant gas is supplied to each of the working chambers 10 (see FIG. 2).

Reference numeral 17 designates a pair of arc-shaped bypass ports formed in the front plate 2, and as shown in FIG. 2, the suction port 11 opens the working chamber 10 along the cam surface 1a, and the opening end 11c.
To the vicinity of the opening position of the discharge port 12 along the working chamber 10 to connect the working chamber 10 and the suction chamber 14. A disk-shaped movable plate 18 is interposed between the front plate 2, the cam ring 1 and the rotor 4, and an outer periphery 18a of the movable plate 18 is provided.
Is in sliding contact with the inner circumference 2a of the front plate 2 on the rotor 4 side, and the movable plate 18 is rotatably supported around the front shaft 4a of the rotor 4. On the outer periphery of the movable plate 18, the movable plate 18
A pair of bypass openings 19 formed by cutting out in a fan shape along the outer periphery of the movable chamber 18 is formed by turning the movable plate 18.
The opening degree of the bypass port 17 that connects the suction chamber 14 and the suction chamber 14 is adjusted. When the movable plate 18 in FIG. 2 is rotated clockwise and the opening degree of the bypass port 17 is increased, the bypass flow rate from the working chamber 10 to the suction chamber 14 is increased and the discharge amount of the compressor is reduced. Conversely, when the movable plate 18 is rotated counterclockwise and the opening degree of the bypass port 17 is reduced, the discharge amount of the compressor increases.

Reference numeral 20 denotes an actuator provided on the head cover 7. The actuator 20 is a cylinder 21 and a piston slidably fitted in the cylinder 21, as shown in FIG.
Has 22. Then, the piston 22 is formed with a small diameter portion 22a, a large diameter portion 22b and a medium diameter portion 22c sequentially from the upper side in the drawing in the axial direction of the piston 22, and the outer periphery of the large diameter portion 22b and the relay portion.
The outer periphery of 22c is in sliding contact with the cylinder 21. Therefore, in the cylinder 21, the first cylinder chamber 23 is formed by the cylinder 21, the small diameter portion 22a and the large diameter portion 22b, and the second cylinder is formed by the cylinder 21, the large diameter portion 22b and the medium diameter portion 22c in this order from the upper side in the drawing. The chamber 24 also has a cylinder 21, a medium diameter portion 22.
The third cylinder chambers 25 are each defined by c. Since the head of the cylinder 21 is open to the suction chamber 14 of the head cover 7, the suction pressure Ps of the compressor is stored in the first cylinder chamber 23.
Is supplied to the second cylinder chamber 24 through a communication hole 26 formed in the cylinder 21 and a control valve (not shown).
13 to communicate with the second cylinder chamber 24 from the compressor under control pressure.
P _D is supplied. The atmospheric pressure Po is introduced into the third cylinder chamber 25 through a filter 27 that is provided at the bottom of the cylinder 21 and removes dust of the passing gas.

An L-shaped arm member 28 is attached to the small-diameter portion 22a, and a long hole 28a is formed at the tip of the arm member 28. As shown in FIG. 2, the link plate 29 is formed in the long hole 28a. The protrusion 29a provided on the outer periphery is engaged. The link plate 29 is rotatably provided around the axis of the rotor 4 between the front plate 2 and the head cover 7, and is movable via a pin 30 attached to the outer peripheral portion of the link plate 29 so as to face the protrusion 29a. It is connected to the plate 18. The pressure is supplied to each cylinder chamber of the actuator 20 and the differential pressure acting on the piston 22 causes the piston 22 to move in the direction indicated by the arrow U in the figure.
When the piston 22 moves in the direction, the movable plate 18 is rotated via the link plate 29 and the pin 30, and the discharge amount of the compressor decreases. Conversely, when the piston 22 moves in the direction of the arrow L, the discharge amount of the compressor increases.

Here, the pressure receiving area of the upper side surface of the large diameter portion 22b that receives the suction pressure Ps in the first cylinder chamber 23 and presses the piston 22 in the L direction is A _1, and the control pressure P _D in the second cylinder chamber 24 is In response to this, the pressure receiving area A ₂ of the lower surface of the large diameter portion 22b that presses the piston 22 in the U direction is set.
The pressure receiving area of the lower end surface of the intermediate diameter portion 22c that is pressed in the direction is defined as A ₃ . Then, it is configured such that A ₁ > A ₃ .

Reference numerals 31 and 32 are provided on the outer circumferences of the large-diameter portion 22b and the medium-diameter portion 22c, respectively, and slidably contact the cylinder 21 to seal the first cylinder chamber 23, the second cylinder chamber 24, and the third cylinder chamber 25 from each other. It is a sealing member.

Next, the operation will be described.

In FIG. 1, when the rotating shaft of the rotor 4 is connected to the engine of the vehicle and driven, and the rotor 4 rotates in the clockwise direction in FIG. 2, the vanes 5 are radiated by centrifugal force and back pressure of the vanes 5. The cam ring 1
It rotates while slidingly contacting the cam surface 1a, the refrigerant gas is sucked into the compressor from the inflow port 15 through the suction port 11, and the refrigerant gas is compressed in the working chamber 10 to become high pressure and high temperature, and the discharge chamber.
It is supplied to the air conditioner (not shown) through 13. At this time, in FIG. 3, since the suction pressure Ps of the compressor is always supplied to the first cylinder chamber 23, the piston 22 is pressed by the force of Ps × A _{1 in} the L direction, and the third cylinder chamber 25 Always atmospheric pressure
Since Po is introduced, the piston 22 is pressed in the U direction by a force of Po × A ₃ . Here, since the suction pressure Ps is, for example, ² to 3 kg / cm ² during normal operation of the compressor, Ps> Po, and since A ₁ > A ₃ , the piston 22 moves in the L direction (Ps × A ₁ )-(Po × A ₃ ) is constantly pressed.

On the other hand, when the control pressure P _D is supplied from the compressor to the second cylinder chamber 24, the piston 22 is pressed in the U direction by the force of P _D × A ₂ . Therefore, when the forces acting on the piston 22 in the U direction and the L direction are balanced and the piston 22 does not move, the following equation is established.

_{P D × A 2 = (Ps} × A 1) - (Po × A 3) ...... Then, when the force acting on the piston 22 becomes the state shown in the following equation, the piston 22 moves in the U direction, and the second
In the figure, the movable plate 18 is rotated in the clockwise direction via the arm member 28, the link plate 29, and the pin 30, and the discharge amount of the compressor is reduced.

P _D × A ₂ ＞ (Ps × A ₁ ) − (Po × A ₃ ) …… When the force acting on the piston 22 reaches the state shown in the following equation, the piston 22 moves in the L direction and the second
In the figure, the rotating plate 18 is rotated counterclockwise through the arm member 28, the link plate 29, and the pin 30 to increase the discharge amount of the compressor.

P _D × A ₂ <(Ps × A ₁ ) − (Po × A ₃ ) …… Here, in an automobile air conditioner, by changing the discharge amount of the compressor in accordance with the load of the air conditioner and maintaining the suction pressure Ps of the compressor at a constant value, the refrigerant in the evaporator of the air conditioner is changed. It is practiced to stabilize the cooling capacity by keeping the evaporation state constant. Also in this embodiment, the actuator 20 can meet the above requirements.
That is, since the discharge amount of the compressor is excessive with respect to the load of the air conditioner, when the suction pressure Ps falls below the target value P _ST , the balance of the force acting on the piston 22 shown in the above equation is lost, and In the state shown, the piston 22 moves in the U direction, and the discharge amount of the compressor decreases. As a result, when the suction pressure Ps rises to the target value P _ST , the piston 22
The forces acting on the are balanced and the piston 22 stops. Further, since the discharge amount of the compressor is too small with respect to the load of the air conditioner, when the suction pressure Ps rises above the target value P _ST , the state shown in the above equation is established and the piston 22 moves in the L direction, The discharge rate of the compressor increases. Therefore, the suction pressure Ps
Is reduced to the target value P _ST , the force acting on the piston 22 is balanced and the piston 22 stops.

Then, since the suction pressure Ps becomes constant and the atmospheric pressure Po is always constant, the force (Ps × A ₁ ) − (Po × A ₃ ) that presses the piston 22 in the L direction, that is, acts on the piston 22. The reaction force can be maintained at a constant value over the entire stroke of the piston 22.

As described above, according to the present embodiment, the piston 22 of the actuator 20 is formed with the small diameter portion 22a, the large diameter portion 22b, and the medium diameter portion 22c, and the first cylinder chamber 23, the second cylinder chamber 24, and the second cylinder chamber 24 are formed in the cylinder 21. The third cylinder chamber 25 is defined, and the first cylinder chamber
Since the suction pressure Ps of the compressor is supplied to 23, the control pressure P _D is supplied to the second cylinder chamber 24, and the atmospheric pressure Po is supplied to the third cylinder chamber 25, the piston 22 is supplied to the piston 22 over the entire stroke of the piston 22. The acting reaction force can be made constant. As a result, the responsiveness and stability of the discharge amount control of the compressor can be made uniform, and the compressor can be downsized. Further, the control pressure can be controlled to a constant pressure, or the control pressure can be positively variably controlled according to the drive feeling.

In this embodiment, the third cylinder 25 has an atmospheric pressure Po.
However, the same effect as that of the present embodiment can be obtained by supplying a pressure lower than the suction pressure of the compressor, for example, a constant vacuum pressure supplied by a vacuum source.

(Effect) According to the present invention, the piston of the actuator has a small diameter portion,
A large diameter portion and a medium diameter portion are formed to define a first cylinder chamber, a second cylinder chamber and a third cylinder in the cylinder, and the suction pressure of the compressor in the first cylinder chamber is controlled to the second cylinder chamber. Since a pressure lower than the suction pressure is supplied to the third cylinder chamber, the reaction force acting on the piston can be made constant over the entire stroke of the piston. Therefore, the responsiveness and stability of the discharge amount control of the compressor can be made uniform, and the size of the compressor can be reduced.

[Brief description of drawings]

1 to 3 are views showing an embodiment of a variable capacity vane type rotary compressor according to the present invention. FIG. 1 is a front vertical sectional view thereof, FIG. 2 is a sectional view taken along line II-II thereof, and FIG. The figure is a front vertical sectional view of the actuator. 1 ... Cam ring, 1a ... Cam surface, 2 ... Front plate, 3 ... Rear plate, 4 ... Rotor, 5 ... Vane, 6 ... Housing, 7 ... Head cover, 10 ... Working chamber, 11 ...... Suction port, 14 ... Suction chamber, 16 ... Suction port, 17 ... Bypass port, 18 ... Movable plate, 19 ... Bypass opening, 20 ... Actuator, 21 ... Cylinder, 22 ... Piston , 22a ... small diameter part, 22b ... large diameter part, 22c ... medium diameter part, 23 ... first cylinder chamber, 24 ... second cylinder chamber, 25 ... third cylinder chamber.

Claims (1)

[Claims] 1. A cam ring having a cam surface formed on an inner periphery thereof,
It is located between the front plate, which has a plurality of suction holes and is provided on the front side of the cam ring, the rear plate that seals the rear side opening of the cam ring, and the front plate and the rear plate. A freely accommodated rotor, a plurality of working chambers formed between the cam ring and the rotor, a plurality of vanes that are inserted into and retracted from the rotor and slidably contact the cam surface at the tip, the cam ring, the front plate A bottomed cylindrical housing accommodating a rear plate, a rotor and a vane; a head cover for sealing the open end of the housing; an intake chamber defined by the head cover and a front plate; It communicates with the suction chamber through the suction port of the plate and maximizes the volume of the working chamber divided by the vane. When Tsu, a plurality of intake ports opening to the cam surface so that communication between the working chamber is cut off,
A bypass port formed on the front plate, which opens to the working chamber along the cam surface and communicates with the suction chamber, and a bypass opening which is rotatably provided between the front plate and the cam ring and adjusts the opening of the bypass port. A variable capacity vane rotary compressor that changes the discharge rate of the compressor by operating the actuator in accordance with the control pressure of the control valve, The actuator has a cylinder and a piston that is slidably fitted in the cylinder and rotates the movable plate, and the piston has a small-diameter portion,
A large-diameter portion whose outer circumference is in sliding contact with the cylinder and a medium-diameter portion whose outer circumference is in sliding contact with the cylinder are sequentially formed in the axial direction of the piston, and compressed into a first cylinder chamber defined by the cylinder, the small-diameter portion, and the large-diameter portion. The suction pressure of the machine is supplied, and the control pressure is supplied from the compressor via the control valve to the second cylinder chamber defined by the cylinder, the large diameter portion and the medium diameter portion, and is defined by the cylinder and the medium diameter portion. Done third
A variable capacity vane type rotary compressor characterized in that a pressure lower than a suction pressure is supplied to a cylinder chamber.