JPH10141219A - Variable displacement compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration in durability from being generated caused by insufficient lubrication even if the operating condition is strict, in a variable displacement compressor. SOLUTION: A passage extending from an evaporator to a suction chamber 13 is opened or closed by a restriction valve 18. First communication passage 28, 31 are communicated with crank chamber 3 and the passage on the upstream side of the restriction valve 18, and a pressure controller adjusts pressure of a pressure chamber 26 by introducing gas in a discharge chamber to the pressure chamber 26 positioned on the lower side of the throttle valve 18. A spring 21 energizes the restriction valve 18 in the direction to resist pressure of the pressure chamber 26. The pressure controller is provided with a second communication passage 23 extending from the discharge chamber 14 to the crank chamber 3, a fixed restriction part 24 arranged on a second communication passage 23, a pressure control valve 25 arranged on the downstream side and the upstream side of the fixed restriction part 24 and for opening or closing the second communication passage 23, and a discharge gas introducing passage 27 for introducing discharge gas from between the fixed restriction part 24 and the pressure control valve 25 into the pressure chamber 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement compressor used for an air conditioner of a vehicle, and more particularly to a pressure control device for a variable displacement compressor.

[0002]

2. Description of the Related Art Generally, in a vehicle air conditioner,
A variable displacement compressor is used. As this type of variable displacement compressor, for example, a variable displacement compressor described in Japanese Patent Application Laid-Open No. 64-56972 (hereinafter referred to as a conventional variable displacement compressor) is known. Have been.

[0003] A conventional variable displacement compressor is a so-called suction throttle type swing plate type variable displacement compressor. A rotor is disposed in a crank chamber formed in a compressor casing, and a main shaft is attached to the rotor. Have been. A swash plate is attached to the rotor via a hinge mechanism. The main shaft passes through the swash plate, and a sleeve is attached to the swash plate to house the main shaft. A space is formed between the outer peripheral surface of the sleeve and the inner wall surface of the swash plate, and the inclination angle of the swash plate with respect to the main shaft can be changed by a hinge mechanism.

An oscillating plate is disposed on the swash plate via a bearing, and a plurality of piston rods are connected to the oscillating plate by ball connection. In the compressor casing,
A plurality of cylinders are formed at predetermined intervals so as to surround the main shaft, and the piston rod is ball-connected to a piston disposed in the cylinder. In the crank chamber, a guide rod is supported on the compressor casing in parallel with the main shaft, and the guide rod is sandwiched by one end of the rocking plate. It is swingable in the main axis direction.

[0005] The rotation of the main shaft transmits the rotation of the rotor to the swash plate, whereby the swinging plate performs a so-called swinging motion and the piston reciprocates to perform a compression operation.
As described above, since the inclination angle of the swash plate with respect to the main shaft can be changed by the hinge mechanism, the piston stroke changes by controlling the inclination angle of the swash plate, thereby changing the compression capacity. it can.

[0006] The conventional variable displacement compressor is provided with a throttle valve for opening and closing a passage from the evaporator to the suction chamber in order to change the compression capacity. A communication passage communicating with the passage is provided. A pressure accumulation chamber is formed at one end of the throttle valve, and gas in the discharge chamber is introduced into the accumulation chamber by a pressure control valve. The throttle valve is urged by a spring in a direction opposing the pressure of the pressure accumulating chamber, and discharge gas in the pressure accumulating chamber flows out of the suction chamber or the upstream side of the throttle valve by the pressure regulator. Then, the pressure of the pressure accumulating chamber acting on the throttle valve is adjusted by the pressure control valve to control the opening and closing of the passage leading to the above-mentioned suction chamber, and a pressure difference is generated between the front and rear of the throttle valve so that the discharge capacity (compression capacity)
Is controlling.

[0007]

In the conventional swinging plate type variable displacement compressor, the lubrication in the crank chamber mainly depends on the oil remaining in the crank chamber. The amount varies depending on the number of revolutions of the compressor, pressure conditions, and the like, and it is difficult to maintain stable lubrication performance in all operating regions.

[0008] For this reason, in the conventional variable displacement compressor, in particular, there is a possibility that the crank chamber oil becomes insufficient under severe operating conditions, and as a result, a durable trouble due to insufficient lubrication may occur.

An object of the present invention is to provide a variable displacement compressor which does not cause a durable trouble due to insufficient lubrication even under severe operating conditions.

[0010]

According to the present invention, a discharge gas acting on a throttle valve is released to a crank chamber, and the crank chamber is forcibly lubricated by oil contained in a discharge gas flow. According to the invention, a compressor housing having a crank chamber formed therein, and a swash plate disposed in the crank chamber and having a variable inclination angle with respect to a main shaft, wherein the swash plate is rotated according to the rotation of the main shaft. The piston reciprocates, is disposed in a pressure chamber formed in the compressor housing, separates the pressure chamber into a first pressure chamber and a second pressure chamber, and extends from the evaporator to the suction chamber. A throttle valve for opening and closing the passage, a first communication passage communicating the crank chamber and the passage upstream of the throttle valve, and introducing a gas in a discharge chamber into the first pressure chamber. Adjust pressure in pressure chamber 1 A force control device, and a spring for urging the throttle valve in a direction against the pressure of the first pressure chamber, wherein the pressure control device adjusts the pressure of the first pressure chamber to adjust the pressure of the first pressure chamber. The pressure control device includes: a second communication path from the discharge chamber to the crank chamber; and a second communication path from the discharge chamber to the crank chamber. A fixed throttle portion, a pressure control valve installed downstream or upstream of the fixed throttle portion to control the opening and closing of the second communication path, and a portion between the fixed throttle portion and the pressure control valve. And a discharge gas introduction passage for introducing a discharge gas into the first pressure chamber.

In this case, it is preferable that the opening area of the valve section of the pressure control valve is set to be larger than the opening area of the fixed throttle section, and further, the suction chamber and the crank chamber located downstream of the throttle valve are provided. And a third communication passage communicating with the throttle valve, and the third communication passage is preferably provided with a fixed throttle having an opening area smaller than the opening area of the throttle valve.

In the compressor according to the present invention, since the opening area of the valve portion of the pressure control valve provided in the second communication passage is set to be larger than the opening area of the fixed throttle, the pressure of the first pressure chamber is fixed. It is determined by the amount of discharge gas introduced through the throttle portion (pressure control valve) and the amount of relief of the pressure control valve (fixed throttle portion) that releases this discharge gas to the crank chamber.

Therefore, by changing the valve opening of the pressure control valve, the pressure of the first pressure chamber can be changed in the range from the discharge chamber pressure to the crank chamber pressure (throttle valve upstream pressure). The throttle valve can be moved in a range from the full opening to the full closing of the suction passage depending on the force of the pressure in the pressure chamber and the magnitude of the spring force.

As a result, the pressure difference between the crank chamber and the suction chamber can be changed, and an arbitrary discharge capacity can be obtained. That is, when in the capacity control state, the pressure control valve is in the open state at an arbitrary opening degree, and the discharge gas is always introduced into the crank chamber through the fixed throttle portion and the pressure control valve. Each component in the room is forcibly lubricated by the oil contained in the discharge gas stream.

Further, even when the suction passage is fully closed by the throttle valve, the gas in the crank chamber is transferred to the suction chamber via the fixed throttle provided in the third communication passage communicating the crank chamber with the suction chamber. Since the refrigerant gas slightly flows, the refrigerant gas and the oil flow into the crank chamber through the first communication path or the second communication path, and the lubrication in the crank chamber is maintained.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

First, a first example of a variable displacement compressor according to the present invention will be described with reference to FIG.

A through hole is formed in the center of the compressor casing 1 and a main shaft 2 is inserted through the through hole. The main shaft 2 is rotatably supported by the compressor casing 1 by bearings 1a and 1b.

A crankcase 3 is formed in the compressor casing 1, and a rotor 4 is disposed in the crankcase 3, and the main shaft 2 is attached to the rotor 4. A swash plate 5 is attached to the rotor 4 via a hinge mechanism 41, the main shaft 2 penetrates the swash plate 5 as shown in the figure, and the inner wall surface of the swash plate 5 (the contact surface between the swash plate and the main shaft) is The swash plate 5 is slidable with respect to the main shaft 2 in contact with the main shaft 2. The tilt angle of the swash plate 5 with respect to the main shaft 2 is changed by the hinge mechanism 41.

The swash plate 5 is provided with a swing plate 6 via a bearing 51, and a plurality of piston rods 7 are connected to the swing plate 6 by ball connection. A plurality of cylinders 8 are formed in the compressor casing 1 at predetermined intervals (angular intervals) so as to surround the main shaft 2, and each piston rod 7 is connected to a piston 9 disposed in the cylinder 8. Is connected to the ball.

In the crankcase 3, a guide rod 10 is supported on the compressor casing 1 in parallel with the main shaft 2.
The guide bar 10 is sandwiched by one end of the swing plate 6, whereby one end of the swing plate 6 can swing in the main axis direction with respect to the guide bar 10.

A cylinder head 12 is disposed on the right end face of the compressor casing 1 in the figure via a valve plate 11, and a right opening end of the compressor casing 1 is closed (the compressor casing 1 and the cylinder head 12 are closed). Constitutes a compressor housing). A suction chamber 13 and a discharge chamber 14 are formed in the cylinder head 12. The suction chamber 13 is connected to a suction port 13a, and the discharge chamber 14 is connected to a discharge port (not shown). A suction hole 11a and a discharge hole 11b are formed in the valve plate 11, and the suction chamber 1
3 and the discharge chamber 14 are the suction hole 11a and the discharge hole 1 respectively.
It communicates with the cylinder 8 via 1b. At the center of the valve plate 11, a suction valve, a discharge valve (both not shown) and a valve retainer 15 are provided with a bolt 16, a nut 1
7 and fastened together.

As shown, the suction chamber 13 and the suction port 1
A pressure chamber is formed between the pressure chamber 3a and the pressure chamber 3a, and a throttle valve 18 is disposed in the pressure chamber. In the figure, throttle valve 18
The pressure chamber 19 (the second pressure chamber) located above is communicated with the suction port 13 a through the communication passage 20, and the upper end of the pressure chamber 19 is closed by the seal member 22.
One end of a spring 21 is attached to the seal member 22, and the other end is attached to the throttle valve 18. As a result, the throttle valve 18 is urged downward by the spring 21.

A communication passage 23 is formed in the cylinder head 12 for communicating the discharge chamber 14 and the crank chamber 3. The communication passage 23 is connected to the discharge chamber 14 and the crank through a fixed throttle 24 and a pressure control valve 25. It communicates with the room 3. When the pressure control valve 25 is opened, the discharge chamber 14 and the crank chamber 3 communicate with each other.

As shown in the drawing, a communication passage 27 communicating from a passage between the fixed throttle 24 and the pressure control valve 25 to a pressure chamber 26 (first pressure chamber) formed below the throttle valve 18 is formed. The discharge gas is introduced into the pressure chamber 26 through the fixed throttle 24.

As shown, a communication passage 28 is formed in the compressor casing 1 and the cylinder head 12.
The communication passage 28 allows the crank chamber 3 to be connected to the suction port 13.
a is always in communication. Further, a communication passage 29 is formed in the compressor casing 1, whereby the crank chamber 3 is always in communication with the suction chamber 13. Further, a fixed throttle 30 is disposed in the communication path 29.

Next, the structure of the pressure control valve 25 will be described.

The pressure control valve 25 has a valve body 251 for opening and closing the communication passage 23. The bellows 252 has its interior evacuated and a spring disposed therein, and
, The pressure of the suction port 13a is sensed. The transmission rod 253 is driven according to the expansion and contraction of the bellows 252, whereby the valve body 251 performs the opening and closing operation. Bellows 2
An electromagnetic coil 254 is disposed opposite to the electromagnetic coil 52, and a plunger 257 is disposed so as to be surrounded by the electromagnetic coil 254. The plunger 257 is slidable with respect to the electromagnetic coil 254, and a transmission rod 255 is fixed to a tip of the plunger 257. Plunger 25
7 is provided with a spring 256 by means of which the plunger 257, ie the transmission rod 255
Are biased upward in the figure. And the electromagnetic coil 25
The plunger 257 presses the valve body 251 in the valve closing direction according to the electromagnetic force of No. 4 and the urging force of the spring 256.

That is, the pressure control valve 25 is
2 responds to the pressure of the suction port 13a sensed by the
The opening and closing of the solenoid 51 is controlled, and the pressure setting changes according to the amount of current supplied to the electromagnetic coil 254. For example, as shown in FIG. 2, it has a pressure control characteristic in which the set pressure changes according to the current of the electromagnetic coil 254.

Referring to FIG. 1, when the illustrated compressor is stopped, the internal pressure is balanced.
As shown in (3), the throttle valve 18 moves downward by the urging force of the spring 21. As a result, the throttle valve 18 blocks the passage to the suction chamber 13.

In this state, when the compressor is started, for example, at a balance pressure of 6 kg / cm ² G, the pressure control valve 25
Is ² kg / cm ² G (in FIG. 2, the current value of the electromagnetic coil is 0.5 A), generally, the minimum capacity has a predetermined discharge capacity other than zero capacity,
The pressure in the suction chamber 13 decreases, and the crank chamber 3 and the suction chamber 1
3 is maintained at a predetermined pressure difference. As a result, the operation is performed with a minimum discharge capacity.

As described above, the crank chamber 3 and the suction chamber 13 communicate with each other via the fixed throttle 30.
Since the crank chamber 3 communicates with the suction port 13a through the communication passage 28, and the chamber above the throttle valve 18 communicates with the suction port 13a through the communication passage 20, the pressure chamber 1
The pressure of 9 gradually decreases.

On the other hand, since the valve body 251 is closed, the discharge pressure acts on the lower chamber (pressure chamber) 26 of the throttle valve 18. Therefore, when the force due to the pressure difference between the pressure chamber 26 and the pressure chamber 19 becomes larger than the urging force of the spring 21, the throttle valve 1
8, the suction port 13a communicates with the suction chamber 13, and the pressure difference between the crank chamber 3 and the suction chamber 13 decreases. As a result, the inclination angle of the swash plate 5, that is, the swinging plate 6, increases, and the discharge capacity reaches a maximum.

The pressure at the suction port 13a is controlled by the pressure control valve 25.
When the set pressure (2 kg / cm ² G) is reached, bellows 2
52 extends, the transmission rod 253 pushes up the valve body 251 to open the valve, and the discharge gas flows to the crank chamber 3. As a result, the pressure in the pressure chamber 26 decreases. As a result, the throttle valve 18 moves downward, narrowing the passage to the suction chamber 13, causing a pressure difference between the suction chamber 13 and the crank chamber 3, and reducing the inclination angle of the swing plate 6. As a result, the discharge capacity decreases. When the pressure in the suction port 13a is going to rise due to the decrease in the discharge capacity, the bellows 252 contracts, and the valve body 2
51 operates in the closing direction, the pressure in the pressure chamber 26 rises, the throttle valve 18 moves upward, and the suction port 13a
The opening area from the inlet to the suction chamber 13 increases. As a result, the pressure difference between the suction chamber 13 and the crank chamber 3 decreases, the tilt angle of the swing plate 6 increases, and the discharge capacity increases.

In this manner, the opening of the valve body 251 and the throttle valve 18 is adjusted so that the pressure of the suction port 13a becomes equal to the set pressure of the pressure control valve 25, and the discharge capacity is controlled. For this reason, in the discharge capacity control state, the discharge gas always flows into the crank chamber 3 via the fixed throttle 24 and the valve body 251, and the components in the crank chamber 3 are forcibly lubricated by the oil contained in the discharge gas flow. Will be done.

By the way, at a low outside air temperature, even if the operation is performed with the minimum capacity, the suction port 1 is set at a pressure lower than the set pressure of the pressure control valve 25.
The pressure of 3a may decrease. In this case, the valve body 25
1 is fully opened, and the pressure in the pressure chamber 26 is
And the throttle valve 18 is operated with the suction passage shut off.

In this state, the gas in the crank chamber 3 is released from the suction chamber 13 through the fixed throttle 30 installed in the communication passage 29.
Therefore, the refrigerant gas and the oil return from the communication passage 28 or the communication passage 23 to the crank chamber, and the lubrication in the crank chamber 3 is maintained.

Next, a second example of the variable displacement compressor according to the present invention will be described with reference to FIG. In FIG.
The same components as those of the variable displacement compressor shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

The variable displacement compressor shown in FIG. 3 is different from the variable displacement compressor shown in FIG.
Control valve 2 for controlling the communication of the communication passage 23 that communicates with the
5 is arranged on the upstream side of the fixed throttle 24. further,
In the illustrated variable displacement compressor, when the pressure in the pressure chamber 26 located below the throttle valve 18 decreases and the throttle valve 18 moves downward, the suction port 13a and the suction chamber 13 communicate with each other. Has become.

That is, in the variable displacement compressor shown in FIG.
When the valve body 251 of the pressure control valve 25 is closed, no discharge gas is introduced into the pressure chamber 26, and as a result, the pressure chamber 26
Is equal to the pressure in the crank chamber 3. That is, since the pressure in the pressure chamber 26 is the same as the pressure in the pressure chamber 19,
The throttle valve 18 moves downward by the urging force of the spring 21,
The suction port 13a communicates with the suction chamber 13.

When the valve body 251 of the pressure control valve 25 is open, the discharge gas is introduced into the pressure chamber 26, and the opening area of the valve portion of the pressure control valve 25 is larger than the opening area of the fixed throttle 24. Since the pressure is large, the pressure in the pressure chamber 26 increases up to the pressure in the discharge chamber 14 at the maximum. For this reason, the throttle valve 18 moves upward, and the opening area to the suction chamber 13 is reduced.

Therefore, also in the variable displacement compressor shown in FIG. 3, the discharge displacement is controlled in the same manner as in the variable displacement compressor shown in FIG. 1, and the inside of the crank chamber 3 is forcibly lubricated by the oil contained in the discharge gas flow. Is done.

In the above example, the swinging plate type variable displacement compressor has been described as an example of the variable displacement compressor. However, the present invention is also applicable to other variable displacement compressors, for example, so-called swash plate type variable displacement compressors. The same applies.

Further, in the above-described example, the pressure chamber 19 communicates with the suction port 13a through the communication passage 20, but the pressure chamber 19 and the suction chamber 13 may communicate with each other.

[0045]

As described above, according to the present invention, even in the variable displacement compressor of the suction throttle type, the discharge gas can flow into the crank chamber, and as a result, the crank chamber is forcibly lubricated. Therefore, there is an effect that the lubrication is not insufficient even under severe operating conditions, and the durability of the compressor is improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first example of a variable displacement compressor according to the present invention.

FIG. 2 is a diagram showing pressure control characteristics of a pressure control valve used in the variable displacement compressor shown in FIG.

FIG. 3 is a diagram showing a second example of the variable displacement compressor according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor casing 2 Main shaft 3 Crank chamber 4 Rotor 5 Swash plate 6 Rocking plate 7 Piston rod 8 Cylinder 9 Piston 10 Guide rod 11 Valve plate 12 Cylinder head 13 Suction chamber 14 Discharge chamber 18 Throttle valve 19, 26 Pressure chamber 21 Spring 23, 27, 28, 29 Communication passage 24, 30 Fixed throttle 25 Pressure control valve

Claims (3)

[Claims] 1. A compressor housing having a crank chamber formed therein, and a swash plate disposed in the crank chamber and having a variable inclination angle with respect to a main shaft, wherein the swash plate is rotated according to the rotation of the main shaft. The piston reciprocates, is disposed in a pressure chamber formed in the compressor housing, separates the pressure chamber into a first pressure chamber and a second pressure chamber, and extends from the evaporator to the suction chamber. A throttle valve for opening and closing the passage, a first communication passage communicating the crank chamber and the passage upstream of the throttle valve, and introducing a gas in a discharge chamber into the first pressure chamber. A pressure control device for adjusting the pressure of the first pressure chamber; and a spring for urging the throttle valve in a direction against the pressure of the first pressure chamber, wherein the first pressure chamber is controlled by the pressure control device. And the throttle valve opens and closes the passage. In the variable displacement compressor which controls the discharge displacement, the pressure control device includes a second communication passage extending from the discharge chamber to the crank chamber, and a fixed communication passage disposed in the second communication passage. A throttle unit, a pressure control valve installed downstream or upstream of the fixed throttle unit for opening and closing the second communication path, and the first pressure from between the fixed throttle unit and the pressure control valve. And a discharge gas introduction passage for introducing discharge gas into the chamber. 2. The variable displacement compressor according to claim 1, wherein an opening area of a valve portion of the pressure control valve is set to be larger than an opening area of the fixed throttle portion. Machine. 3. The variable displacement compressor according to claim 1, further comprising a third communication passage communicating between the suction chamber located downstream of the throttle valve and the crank chamber. A variable displacement compressor, wherein the third communication passage is provided with a fixed throttle having an opening area smaller than an opening area of the throttle valve.