JP2000291540A - Swash plate type variable displacement compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent freezing of an evaporator by closing a pilot valve by breaking current-carrying to a solenoid of a flow rate control valve drive mechanism, closing a flow rate control valve, and stopping reduction of evaporator side pressure of an upstream side from the flow rate control valve in a low pressure side refrigerant passage. SOLUTION: A means for regulating the pressure of a refrigerant intake chamber 7 formed on a rear housing of a compressor, and a crank chamber 5 is provided with a flow rate control valve 31 for opening a spool valve 33 energized in the valve closing direction by a spring 34 with pressure acted in a pressure chamber 35. Then it is provided with a flow rate control valve drive mechanism 32, which is disposed in a passage 40 for communicating a refrigerant delivery chamber 8 and the pressure chamber 35 with each other, and which has a pilot valve 41 whose opening is controlled by the excitation of a solenoid 42 and which is disposed for leading high pressure side refrigerant into the pressure chamber 35. Also the device is provided with a feed back means 46 for regulating an opening of the flow rate control valve 31 by sensing the change by a diaphragm 47, when pressure of an evaporator side disposed upstream from the flow rate control valve 31 is changed more than constant pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swash plate type variable displacement compressor which is interposed in a refrigeration cycle of a vehicle air conditioner or the like and is used for compressing refrigerant gas.

[0002]

2. Description of the Related Art In a swash plate type variable displacement compressor, as disclosed in Japanese Patent Publication No. Hei 6-89941, for example, the opening degree of a pilot valve is controlled by an exciting current of a solenoid to form a refrigerant discharge chamber. Is known in which the high-pressure side refrigerant acts on the back of a piston valve, and the piston valve controls the flow rate of the refrigerant flowing into the refrigerant suction chamber.

[0003]

The conventional swash plate type variable displacement compressor has a basic structure of a so-called clutch type in which an electromagnetic clutch is incorporated in a compressor drive pulley, so that the structure is complicated. Not only that, the weight increases, and the number of parts also increases, which is disadvantageous in terms of cost.

Further, when the compressor is connected to a clutch and the refrigerant inflow into the refrigerant suction chamber of the compressor is to be reduced to zero in order to avoid freezing of the evaporator, a solenoid for operating the pilot valve is required. It is necessary to maximize the exciting current to cause the piston valve to perform a full stroke toward the valve closing side, which increases power consumption.

In view of the above, the present invention enables the operation of the compressor to be turned on and off without providing a clutch, thereby achieving a clutchless operation, and demagnetizing a solenoid that operates a pilot valve for controlling the flow rate of the refrigerant. Accordingly, an object of the present invention is to provide a swash plate type variable displacement compressor capable of reducing the amount of refrigerant flowing into the refrigerant suction chamber of the compressor to zero and preventing the evaporator from freezing.

[0006]

According to the first aspect of the present invention, there is provided a pressure control device for controlling a flow rate of a refrigerant flowing into a refrigerant suction chamber to adjust a pressure between the refrigerant suction chamber and the crank chamber. In the plate-type variable displacement compressor, the pressure adjusting means includes a spool valve, a spring for urging the spool valve in a valve closing direction, and a pressure chamber for accumulating a pressure for operating the spool valve in a valve opening direction. A flow control valve provided in the low-pressure side refrigerant passage upstream of the suction chamber, and a passage provided in communication between the refrigerant discharge chamber and the pressure chamber, which are normally closed by a spring and provided by an excitation current of the solenoid. A flow control valve drive mechanism having a pilot valve whose valve opening is controlled to control the introduction of the high-pressure side refrigerant of the refrigerant discharge chamber into the pressure chamber as an operating pressure, and the flow control valve drive mechanism includes: The par At the time of the predetermined opening state of the lot valve, when the pressure on the evaporator side upstream of the flow control valve of the low-pressure side refrigerant passage introduced through the feedback passage has changed from a certain pressure, this pressure change is sensed by the diaphragm, The pilot valve is actuated in a valve closing direction or a valve opening direction via a plunger to provide a feedback means for adjusting the valve opening of the flow control valve to keep the pressure on the evaporator side constant. When the low-pressure side refrigerant passage is fully closed and shut off, a high-pressure side refrigerant introduction passage which connects the refrigerant discharge chamber and the feedback path is provided.

According to a second aspect of the present invention, the plunger according to the first aspect is formed hollow, and when the plunger is opened, the front end opening is closed by the pilot valve and the pilot valve is closed. Is set to have a length such that the distal end opening is opened when fully closed, and the high-pressure side refrigerant introduction passage is constituted by the hollow plunger.

[0008] In the invention of claim 3, claims 1 and 2
Is characterized in that the pressure receiving areas on both sides of the spool groove are made equal.

According to the invention of claim 4, claims 1 to 3 are provided.
The flow control valve driving mechanism described in (1) is characterized by including a pressure adjusting passage that communicates the crank chamber with the evaporator side upstream of the flow control valve in the low-pressure side refrigerant passage.

In the invention of claim 5, claims 1 to 4 are provided.
The flow control valve drive mechanism described in (1) is characterized by including a pressure adjusting passage that communicates the pressure chamber of the flow control valve with the refrigerant suction chamber.

[0011]

According to the first aspect of the present invention, when the supply current to the solenoid of the flow control valve drive mechanism is set to 0 and the solenoid is demagnetized, the pilot valve closes and the pressure chamber of the flow control valve is closed. In order to cut off the supply of the operating pressure of the evaporator, the spool valve closes to reduce the amount of the refrigerant flowing into the refrigerant suction chamber to zero, stop the decrease in the evaporator-side pressure upstream of the flow control valve in the low-pressure side refrigerant passage, and stop the evaporator. Freezing prevention can be performed.

Therefore, when the evaporator operates to prevent freezing, the supply of the exciting current to the solenoid may be stopped, so that the power consumption can be reduced and the load on the compressor can be reduced to almost zero by fully closing the spool valve. Therefore, the output of the driving source can be improved.

By stopping the supply of the exciting current to the solenoid and closing the spool valve of the flow control valve in this manner, the pressure in the refrigerant suction chamber drops, and the internal pressure of the cylinder in which the refrigerant is drawn is reduced. The differential pressure from the crank chamber becomes the maximum, the swash plate is inclined by the moment due to the force applied to each piston, and the piston stroke is minimized to make the compression work of the compressor almost zero.
The operation of the compressor can be interrupted / continued by degaussing, and the clutch can be eliminated.

Accordingly, the structure of the compressor can be simplified, the size and weight can be reduced, and the compressor can be advantageously obtained.

Furthermore, when the vehicle is suddenly accelerated or decelerated when the pilot valve is set to the predetermined opening degree by the predetermined excitation current, the pressure on the evaporator upstream of the flow control valve in the low-pressure side refrigerant passage changes. However, since this pressure change is immediately sensed by the diaphragm of the feedback means and the pilot valve is operated in the valve closing direction or the valve opening direction via the plunger, the evaporator side pressure can be maintained at a constant pressure. Fluctuations in the control temperature of the evaporator due to sudden acceleration and deceleration of the vehicle can be avoided.

When the low pressure side refrigerant passage is fully closed and shut off by the spool valve of the flow control valve, the refrigerant discharge chamber and the feedback passage are communicated by the high pressure side refrigerant introduction passage, and the low pressure side refrigerant is passed through the feedback passage. In order to increase the pressure on the evaporator side by introducing the high-pressure side refrigerant to the evaporator side of the refrigerant passage, even if the refrigerant leaks from the spool valve to the refrigerant suction chamber, the evaporator side pressure is reduced and the evaporator is prevented from freezing. Can be performed reliably.

According to the invention described in claim 2, according to claim 1
In addition to the effects of the invention, the high-pressure side refrigerant introduction passage is constituted by the plunger itself for controlling the pilot valve held by the diaphragm of the feedback means, and the opening and closing control of the high-pressure side refrigerant introduction passage is controlled by the pilot valve. Therefore, a dedicated passage configuration and control valve setting are not required, the structure can be simplified, and the cost can be advantageously obtained.

According to the third aspect of the invention, in addition to the effects of the first and second aspects, the pressure receiving areas on both side surfaces of the spool groove provided in the spool valve of the flow control valve are equalized. By controlling the spring force of the spring that urges the spool valve in the valve closing direction and the operating pressure that acts on the pressure chamber, the accuracy of the opening and closing stroke of the spool valve can be obtained. Can be done.

According to the invention described in claim 4, according to claim 1,
In addition to the effects of the inventions of (1) to (3), since the crank chamber communicates with the evaporator side upstream of the flow control valve of the low-pressure side refrigerant passage by the pressure adjustment passage and is kept at the same pressure, the blow-by gas in the crank chamber And the accuracy of the variable displacement control can be improved.

According to the invention described in claim 5, according to claim 1,
In addition to the effects of the fourth to fourth aspects, since the pressure chamber of the flow control valve communicates with the refrigerant suction chamber through the pressure adjusting passage, the operating pressure of the pressure chamber is quickly increased when the pilot valve is closed. Since the spool valve can be released to the chamber and closed, the responsiveness can be improved.

[0021]

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

In FIG. 1, reference numeral 1 denotes a compressor housing, a cylinder block 2 having a plurality of cylinder bores 3, and a front housing 4 which is disposed in front of the cylinder block 2 and forms a crank chamber 5 between the cylinder block 2 and the cylinder block 2. And a valve plate 9 on the rear side of the cylinder block 2.
And a rear housing 6 that forms a refrigerant suction chamber 7 and a refrigerant discharge chamber 8.

A drive shaft 10 is provided in the crank chamber 5.
A journal 14 connected to a sleeve 12 slidably fitted on the drive shaft 10 by a pin 13 so as to swing freely, and a swash plate 15 screwed and fixed to the outer periphery of the journal 14. It has.

The journal 14 is connected to the drive plate 11 through an arc-shaped elongated hole 16 and a pin 17, and the swing is regulated by the elongated hole 16.

A piston 18 fitted in each cylinder bore 3
Is connected to the swash plate 15 via a pair of shoes 19 sandwiching the swash plate 15.

A pulley 20 is rotatably mounted on the outer end of the drive shaft 10 via a bearing 21, and a first drive transmission plate 22 screwed and fixed to the inner periphery of the pulley 20. The drive shaft 10 is rotated by the pulley 20 by slidably connecting the second drive transmission plate 23 fixed to the terminal 10 with a certain drive torque or more.

The inclination angle of the swash plate 15 is adjusted by the moment around the pin 17 of the swash plate 15 generated by the pressure difference between the refrigerant suction chamber 7 and the crank chamber 5 adjusted by the pressure adjusting means 30 provided in the rear housing 6. Controlled, this swash plate 1
By changing the angle of 5, the stroke of the piston 18 is changed to change the discharge capacity of the refrigerant.

As shown in FIG. 2, the pressure adjusting means 30
A flow control valve 31 provided in the low-pressure side refrigerant passage 25 near the refrigerant inlet 24 upstream of the refrigerant suction chamber 7 for directly controlling the amount of refrigerant flowing into the refrigerant suction chamber 7;
1 and a flow rate control valve drive mechanism 32 for controlling the drive of the motor.

The flow control valve 31 includes a spool valve 33 disposed orthogonal to the low-pressure side refrigerant passage 25 and a spool valve 33.
And a spool valve 3 for urging the spool valve 3 in the valve closing direction.
And a pressure chamber 35 for accumulating a pressure that causes the valve 3 to act in the valve opening direction.

The both sides 36a and 36b of the spool groove 36 of the spool valve 33 have the same pressure receiving area.

The spring chamber 3 containing the spring 34
The passage 7 communicates with the refrigerant suction chamber 7 downstream of the flow control valve 31 of the low-pressure refrigerant passage 25 through a passage 38.

The flow control valve drive mechanism 32 is provided with the refrigerant discharge chamber 8.
A ball valve 41 provided as a pilot valve that is provided in a passage 40 that communicates with the pressure chamber 35 and that controls the introduction of the high-pressure side refrigerant of the refrigerant discharge chamber 8 into the pressure chamber 35 as an operating pressure. And a solenoid 42 for controlling the valve opening of the valve 41.

The ball valve 41 is normally seated on a valve seat by a spring 43 and closed.

The solenoid 42 is supplied with an exciting current to move the armature 44 upward in FIG. 2 and push the plunger 45 to control the valve opening of the ball valve 41.

The flow control valve drive mechanism 32 detects the pressure on the evaporator side upstream of the flow control valve 31 in the low pressure side refrigerant passage 25, and variably controls the pressure on the evaporator side by the excitation current of the solenoid 42. Is provided with feedback means 46 for keeping the constant.

The feedback means 46 includes an atmospheric pressure chamber 48
Diaphragm 47 which separates the refrigerant pressure chamber 49 from the fuel pressure chamber 49, a feedback path 50 which introduces the pressure on the evaporator side into the refrigerant pressure chamber 49, and which is held by the diaphragm 47 and is coaxially opposed to the plunger 45 of the solenoid 42. And a plunger 51 for controlling the opening of the ball valve 41. When the ball valve 41 is controlled to a predetermined opening, the pressure of the low-pressure side refrigerant passage 25 on the evaporator side becomes lower than a constant pressure. When the pressure changes, the pressure change is sensed by the diaphragm 47, the ball valve 41 is operated in the valve closing direction or the valve opening direction by the plunger 51, and the valve opening of the flow control valve 31 is adjusted to reduce the pressure on the evaporator side. It is kept constant.

The refrigerant pressure chamber 49 communicates with the crank chamber 5 through a pressure adjusting passage 52, and the crank chamber 5 communicates with the low-pressure refrigerant passage 25 on the evaporator side upstream of the flow control valve 31.

A pressure regulating passage 53 communicating with the refrigerant suction chamber 7 is connected downstream of the ball valve 41 of the passage 40 communicating with the pressure chamber 35 of the flow control valve 31. 53, the pressure chamber 31 and the refrigerant suction chamber 7
And communicates.

The flow control valve driving mechanism 32 includes:
When the low pressure side refrigerant passage 25 is fully closed and shut off by the spool valve 33, a high pressure side refrigerant introduction passage 54 that communicates the refrigerant discharge chamber 8 with the feedback passage 50 is provided.

In this embodiment, as shown in FIG. 3, the plunger 51 held by the diaphragm 47 of the feedback means 46 is formed hollow, and the high-pressure side refrigerant introduction passage 54 is constituted by the plunger 51.

A refrigerant pressure chamber 49 is provided at the upper end of the plunger 51.
A communication hole 55 is provided at an appropriate position facing the front end, and the plunger 51 has a tip opening closed by the ball valve 41 when the ball valve 41 is open, and the ball valve 41 is fully closed. When the ball valve 41 is fully closed, the high pressure side refrigerant introduction passage 54 is opened, and the refrigerant discharge chamber 8 and the feedback passage 50 pass through the refrigerant pressure chamber 49. It is made to communicate.

According to the structure of the above embodiment, when the solenoid 42 is excited, the valve opening of the ball valve 41 is controlled according to the exciting current, and the high-pressure side refrigerant in the refrigerant discharge chamber 8 passes through the ball valve 41. And flows into the passage 40 and is introduced into the pressure chamber 35 of the flow control valve 31 as an operating pressure.

In response to the pressure in the pressure chamber 35, the spool valve 33 moves in the direction in which the spool valve 33 opens against the spring force of the spring 34, and expands the flow path of the low-pressure side refrigerant passage 25 to increase the refrigerant suction chamber 7 To control the amount of refrigerant flowing into the cooling chamber, adjust the pressure difference between the refrigerant suction chamber 7 and the crank chamber 5, control the inclination angle of the swash plate 15, and change the stroke of the piston 18 to control the amount of refrigerant discharged. Thus, the temperature of the evaporator (not shown) is controlled.

Here, for the purpose of preventing the evaporator from freezing during the operation of the refrigeration cycle, the amount of the refrigerant flowing into the refrigerant suction chamber 7 is reduced to zero, and the flow control valve 31 in the low-pressure side refrigerant passage 25 is set.
To stop the pressure drop on the evaporator side upstream of
The supply current to the solenoid 42 is set to 0 and the solenoid 4
2 can be demagnetized and the ball valve 41 is closed by the demagnetization of the solenoid 42 to stop the supply of the operating pressure to the pressure chamber 35 of the flow control valve 31. By closing the valve, the low-pressure side refrigerant passage 25 is shut off, the amount of refrigerant flowing into the refrigerant suction chamber 7 is reduced to zero, the inclination angle of the swash plate 15 is controlled, the piston stroke is reduced, and the low-pressure side refrigerant passage 25 is reduced. The lowering of the evaporator side pressure is stopped to prevent the evaporator from freezing.

As described above, the supply of the exciting current to the solenoid 42 may be stopped during the anti-freezing operation of the evaporator, so that the power consumption can be reduced and the load on the compressor can be reduced by fully closing the spool valve 33. Is substantially zero, so that the output of the drive source can be improved.

As described above, when the supply of the exciting current to the solenoid 42 is stopped and the spool valve 33 of the flow control valve 31 is operated to close, the pressure of the refrigerant suction chamber 7 drops, and the cylinder internal pressure and the crank pressure are reduced. The differential pressure with chamber 5 is at a maximum,
In order to make the swash plate 15 tilt by the moment around the pin 17 and minimize the stroke of the piston 18 to make the compression work of the compressor almost zero, the operation of the compressor is interrupted and continued by energizing and demagnetizing the solenoid 42. It is possible to eliminate the clutch, which conventionally interrupts the transmission of drive to the compressor, and eliminate the need for clutches. For example, in the case of an electromagnetic clutch, heavy magnets and coils are not required. Can be.

Accordingly, the structure of the compressor can be simplified, the size and weight can be reduced, and the wiring for supplying electricity to the clutch can be eliminated, and the cost can be advantageously obtained.

The solenoid 4 of the flow control valve mechanism 32
When a predetermined exciting current is supplied to the ball valve 2 and the ball valve 41 is kept at a predetermined opening degree, when the vehicle is rapidly accelerated or decelerated, the evaporator upstream of the flow control valve 31 in the low-pressure side refrigerant passage 25 due to fluctuations in the rotational speed of the compressor. The side pressure changes, but this pressure change is immediately sensed by the diaphragm 47 of the feedback means 46 and the ball valve 41 is actuated in the valve closing direction or the valve opening direction via the plunger 51 to reduce the evaporator side pressure. Since the pressure can be maintained at a constant value corresponding to the exciting current of the solenoid 42, fluctuations in the control temperature of the evaporator due to sudden acceleration and deceleration of the vehicle can be avoided.

When such an evaporator operates to prevent freezing, that is, when the ball valve 41 is closed and the low-pressure side refrigerant passage 25 is fully closed by the spool valve 33 of the flow control valve 31, as described above. When the ball valve 41 is closed, the high pressure side refrigerant introduction passage 54 of the plunger 51 is opened, the refrigerant discharge chamber 8 communicates with the feedback passage 50, and the low pressure side refrigerant passage 25 passes through the feedback passage 50.
Since the high-pressure side refrigerant is introduced into the evaporator side to increase the pressure on the evaporator side, even if the refrigerant leaks from the spool valve 33 to the refrigerant suction chamber 7, the freezing of the evaporator can be reliably prevented. .

Particularly, in this embodiment, the high-pressure side refrigerant introduction passage 5
4 is constituted by the plunger 51 itself held by the diaphragm 47 of the feedback means 46, and the opening and closing of the plunger 51 is controlled by the ball valve 41, so that a dedicated passage configuration and control valve setting are not required, and the structure is reduced. It can be simplified and cost-effectively obtained.

Here, both side surfaces 36a, 36b of the spool groove 36 provided in the spool valve 33 of the flow control valve 31 described above.
Since the pressure receiving areas are equal, the spring force of the spring 34 for urging the spool valve 33 in the valve closing direction and the pressure chamber 3
5 only by controlling the operating pressure acting on the spool valve 3.
The accuracy of the opening / closing stroke of No. 3 can be obtained, and highly accurate flow rate control can be performed.

Since the pressure in the crank chamber 5 is maintained at a constant level by communicating with the evaporator upstream of the flow control valve 31 in the low-pressure side refrigerant passage 25 through the pressure adjusting passage 52, the blow-by gas in the crank chamber 5 is maintained. And the accuracy of the variable displacement control can be improved.

Further, since the pressure chamber 35 of the flow control valve 31 communicates with the refrigerant suction chamber 7 through the pressure adjustment passage 53, the ball valve 41 is closed when the solenoid 42 of the flow control valve drive mechanism 32 is demagnetized. Then, the operating pressure of the pressure chamber 35 is quickly released to the refrigerant suction chamber 7 side so that the spool valve 3
Since the valve 5 can be operated to close the valve, responsiveness can be improved.

[Brief description of the drawings]

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

FIG. 2 is a sectional explanatory view systematically showing a pressure adjusting unit in the embodiment.

FIG. 3 is an enlarged view showing a configuration of a high-pressure side refrigerant introduction passage.

[Explanation of symbols]

 Reference Signs List 5 Crank chamber 7 Refrigerant suction chamber 8 Refrigerant discharge chamber 25 Low pressure side refrigerant passage 30 Pressure adjusting means 31 Flow control valve 32 Flow control valve drive mechanism 33 Spool valve 34 Spring 35 Pressure chamber 40 Passage 41 Pilot valve 42 Solenoid 43 Spring 46 Feedback means 47 Diaphragm 50 Feedback path 51 Plunger 52,53 Pressure adjustment path 54 High-pressure side refrigerant introduction path

Claims (5)

[Claims] A swash plate type variable pressure control means (30) for controlling a flow rate of a refrigerant flowing into a refrigerant suction chamber (7) to adjust a pressure between the refrigerant suction chamber (7) and a crank chamber (5). In the displacement compressor, the pressure adjusting means (30) is moved in the direction of opening the spool valve (33), a spring (34) for urging the spool valve (33) in the valve closing direction, and the valve opening direction of the spool valve (33). A flow control valve (31) provided in a low-pressure side refrigerant passage (25) upstream of the refrigerant suction chamber (7); and a refrigerant discharge chamber (8). A passage (40) communicating with the pressure chamber (35) is provided, and in a normal state, a spring (4) is provided.
The pilot valve (41) is closed by 3), and the valve opening is controlled by the excitation current of the solenoid (42) to control the introduction of the high-pressure side refrigerant of the refrigerant discharge chamber (8) into the pressure chamber (35) as the operating pressure. Flow control valve drive mechanism having a valve (32)
And the low pressure side refrigerant passage (50) introduced through a feedback passage (50) when the pilot valve (41) is in a predetermined opening state. 2
5) When the pressure on the evaporator side upstream of the flow control valve changes from a fixed pressure, this pressure change is detected by the diaphragm (4).
7), and through the plunger (51) held in the diaphragm (47), the pilot valve (4).
1) is operated in a valve closing direction or a valve opening direction to provide a feedback means (46) for adjusting the valve opening of the flow control valve (31) to maintain the pressure on the evaporator side constant, and the spool valve (33) Low pressure side refrigerant passage (25)
A swash plate type variable displacement compressor characterized in that a high-pressure side refrigerant introduction passage (54) communicating the refrigerant discharge chamber (8) and the feedback passage (50) is provided when fully closed. 2. The plunger (51) is formed hollow, and when the plunger (51) is opened, the front end opening is closed by the pilot valve (41), and the pilot valve (41) is closed. ) Is set to a length such that the tip opening is opened when fully closed, and the high-pressure side refrigerant introduction passage (5) is set.
The swash plate type variable displacement compressor according to claim 1, wherein 4) is constituted by the hollow plunger (51). 3. A swash plate type variable displacement compressor according to claim 1, wherein said spool valve (33) has equal pressure receiving areas on both side surfaces of said spool groove (36). 4. A flow control valve drive mechanism (32) for connecting a pressure control passage (40) that communicates between a crank chamber (5) and an evaporator side upstream of a flow control valve (31) of a low pressure side refrigerant passage (25). 52. The swash plate type variable displacement compressor according to any one of claims 1 to 3, further comprising (52). 5. The flow control valve drive mechanism (32) includes a pressure adjusting passage (53) that communicates a pressure chamber (35) of the flow control valve (31) with the refrigerant suction chamber (7). The swash plate type variable displacement compressor according to any one of claims 1 to 4, wherein