JP4031141B2 - Swash plate type variable capacity compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a swash plate type variable capacity compressor that is interposed in a refrigeration cycle of a vehicle air conditioner or the like and is used to compress refrigerant gas.
[0002]
[Prior art]
In some swash plate type variable capacity compressors, for example, as disclosed in Japanese Patent Publication No. 6-87741, the opening degree of the pilot valve is controlled by the excitation current of the solenoid, and the high-pressure side refrigerant in the refrigerant discharge chamber is supplied. There has been known one in which the flow rate of the refrigerant flowing into the refrigerant suction chamber is controlled by the piston valve acting on the back portion of the piston valve.
[0003]
[Problems to be solved by the invention]
Since the conventional swash plate type variable capacity compressor is based on a so-called clutch type in which an electromagnetic clutch is incorporated in a compressor driving pulley, the structure becomes complicated and the weight increases. In addition, it is undeniable that the number of parts is increased and disadvantageous in terms of cost.
[0004]
In addition, when the compressor is connected to the clutch and the refrigerant flow rate into the refrigerant suction chamber of the compressor is to be zero in order to avoid freezing of the evaporator, the excitation current of the solenoid that operates the pilot valve is set to 0. It is necessary to make the piston valve full stroke toward the valve closing side at the maximum, resulting in an increase in power consumption.
[0005]
Therefore, the present invention can control the operation of the compressor without a clutch and can be made clutchless and demagnetize the solenoid that operates the pilot valve that controls the flow rate of the refrigerant. A swash plate type variable capacity compressor capable of preventing the evaporator from freezing by setting the refrigerant inflow amount to the refrigerant suction chamber of the compressor to zero is provided.
[0006]
[Means for Solving the Problems]
In the first aspect of the invention, in the swash plate type variable capacity compressor provided with pressure adjusting means for adjusting the pressure between the refrigerant suction chamber and the crank chamber by controlling the flow rate of the refrigerant flowing into the refrigerant suction chamber.
The pressure adjusting means includes a spool valve, a spring that urges the spool valve in the valve closing direction, and a pressure chamber that accumulates pressure that causes the spool valve to act in the valve opening direction, and is on the low pressure side upstream of the refrigerant suction chamber A flow control valve provided in the refrigerant passage;
It is provided in a passage that connects the refrigerant discharge chamber and the pressure chamber, and is normally closed by a spring. The valve opening is controlled by the solenoid excitation current, and the high-pressure side refrigerant in the refrigerant discharge chamber is used as the operating pressure. A flow control valve drive mechanism having a pilot valve for introducing and controlling the pressure chamber,
In the flow control valve drive mechanism, when the pilot valve is in a predetermined opening state, the pressure on the evaporator side upstream of the flow control valve of the low pressure side refrigerant passage introduced through the feedback passage changes from a constant pressure. When this occurs, the pressure change is detected by the diaphragm, the pilot valve is operated in the valve closing direction or the valve opening direction via the plunger, the valve opening of the flow control valve is adjusted, and the pressure on the evaporator side is kept constant. While providing feedback means to hold,
A high-pressure side refrigerant introduction passage is provided that communicates the refrigerant discharge chamber and the feedback passage when the low-pressure side refrigerant passage is fully closed by the spool valve.
[0007]
According to a second aspect of the present invention, the plunger according to the first aspect is formed in a hollow shape, the front end opening of the plunger is closed by the pilot valve when the pilot valve is opened, and the pilot valve is fully closed. It is characterized in that it is set to a length that sometimes opens the tip opening, and the high-pressure side refrigerant introduction passage is constituted by the hollow plunger.
[0008]
According to a third aspect of the invention, the spool valve according to the first and second aspects is characterized in that the pressure receiving areas on both side surfaces of the spool groove are equal.
[0009]
In a fourth aspect of the invention, the flow control valve drive mechanism according to any one of the first to third aspects communicates the crank chamber and the evaporator side upstream of the flow control valve of the low pressure side refrigerant passage. It is characterized by having.
[0010]
According to a fifth aspect of the present invention, the flow control valve drive mechanism according to any one of the first to fourth aspects includes a pressure adjusting passage that communicates the pressure chamber of the flow control valve and the refrigerant suction chamber. Yes.
[0011]
【The invention's effect】
According to the first aspect of the present invention, when the current supplied to the solenoid of the flow control valve drive mechanism is set to 0 and the solenoid is demagnetized, the pilot valve is closed and the operating pressure is supplied to the pressure chamber of the flow control valve. Therefore, the spool valve is closed to reduce the amount of refrigerant flowing into the refrigerant suction chamber to zero, and stop the decrease in the evaporator side pressure upstream of the flow control valve in the low pressure side refrigerant passage, thereby preventing the evaporator from freezing. be able to.
[0012]
Therefore, at the time of the evaporator freezing prevention operation, it is only necessary to stop the supply of the excitation current to the solenoid, so that the power consumption can be reduced and the load of the compressor is made almost zero by the fully closed operation of the spool valve. The output of the drive source can be improved.
[0013]
In addition, by stopping the supply of the excitation current to the solenoid and closing the spool valve of the flow control valve in this way, the pressure in the refrigerant suction chamber drops and the cylinder internal pressure and the crank chamber that sucked the refrigerant In order to minimize the piston stroke and reduce the compression work of the compressor to almost zero by the moment caused by the force applied to each piston, the compression work of the compressor is almost zero. The operation can be interrupted / interrupted and clutchless can be achieved.
[0014]
Therefore, the structure of the compressor can be simplified, a reduction in size and weight can be realized, and a cost advantage can be obtained.
[0015]
Furthermore, when the pilot valve is set to a predetermined opening with a predetermined excitation current, the evaporator side pressure upstream of the flow control valve in the low pressure side refrigerant passage changes when the vehicle is suddenly accelerated or decelerated. The pressure change is immediately detected by the diaphragm of the feedback means, and the pilot valve is actuated in the valve closing direction or the valve opening direction via the plunger so that the evaporator side pressure can be maintained at a constant pressure. It is possible to avoid fluctuations in the evaporator control temperature due to acceleration and deceleration.
[0016]
Further, when the low pressure side refrigerant passage is fully closed 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 passage is connected via the feedback passage. In order to increase the pressure on the evaporator side by introducing the high-pressure side refrigerant to the evaporator side, even if the refrigerant leaks from the spool valve to the refrigerant suction chamber, the evaporator side pressure is not reduced and the evaporator is reliably prevented from freezing. It can be carried out.
[0017]
According to the second aspect of the present invention, in addition to the effect of the first aspect, the high pressure side refrigerant introduction passage is constituted by the pilot valve control plunger itself held by the diaphragm of the feedback means, and the high pressure side Since the opening / closing control of the side refrigerant introduction passage is performed by the pilot valve, a dedicated passage configuration and control valve setting are not required, the structure can be simplified, and the cost can be advantageously obtained.
[0018]
According to the third aspect of the invention, in addition to the effects of the first and second aspects of the invention, the pressure receiving areas on both side surfaces of the spool groove provided in the spool valve of the flow rate control valve are equalized. By simply managing the spring force of the spring that urges the valve in the valve closing direction and the operating pressure acting on the pressure chamber, the spool valve opening / closing stroke accuracy can be achieved, and high-precision flow rate control can be performed. Can do.
[0019]
According to the fourth aspect of the invention, in addition to the effects of the first to third aspects, the crank chamber communicates with the evaporator side upstream of the flow rate control valve of the low-pressure side refrigerant passage by the pressure adjustment passage. Since the pressure is kept constant, the pressure fluctuation due to the blow-by gas in the crank chamber can be eliminated and the accuracy of the variable capacity control can be improved.
[0020]
According to the fifth aspect of the invention, in addition to the effects of the first to fourth aspects of the invention, the pressure chamber of the flow rate control valve communicates with the refrigerant suction chamber through the pressure adjusting passage, so that the pilot valve is closed. In this case, the operating pressure in the pressure chamber can be quickly released to the refrigerant suction chamber and the spool valve can be closed, so that the responsiveness can be improved.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0022]
In FIG. 1, reference numeral 1 denotes a compressor housing, a cylinder block 2 having a plurality of cylinder bores 3, a front housing 4 which is disposed on the front side of the cylinder block 2 and forms a crank chamber 5 between the cylinder block 2, and a cylinder A rear housing 6 is provided on the rear side of the block 2 with a valve plate 9 interposed therebetween to form a refrigerant suction chamber 7 and a refrigerant discharge chamber 8.
[0023]
In the crank chamber 5, a drive plate 11 fixed to the drive shaft 10, a journal 14 slidably connected by a pin 13 to a sleeve 12 slidably fitted to the drive shaft 10, and an outer periphery of the journal 14 And a swash plate 15 that is screwed and fixed thereto.
[0024]
The journal 14 is connected via an arc-shaped long hole 16 of the drive plate 11 and a pin 17, and swinging is restricted by the long hole 16.
[0025]
The piston 18 fitted to each cylinder bore 3 is connected to the swash plate 15 via a pair of shoes 19 sandwiching the swash plate 15.
[0026]
A pulley 20 is rotatably mounted on an outer end portion of the drive shaft 10 via a bearing 21, a first drive transmission plate 22 screwed and fixed to the inner periphery of the pulley 20, and a terminal of the drive shaft 10. The drive shaft 10 is rotated by the pulley 20 by slidably connecting the second drive transmission plate 23 fixed to the drive plate 23 with a certain drive torque or more.
[0027]
The inclination angle of the swash plate 15 is controlled by the moment around the pin 17 of the swash plate 15 generated by the differential pressure between the refrigerant suction chamber 7 and the crank chamber 5 adjusted by the pressure adjusting means 30 disposed in the rear housing 6. By changing the angle of the swash plate 15, the stroke of the piston 18 is changed to change the refrigerant discharge capacity.
[0028]
As shown in FIG. 2, the pressure adjusting means 30 is provided in the low-pressure side refrigerant passage 25 in the vicinity of the refrigerant inlet 24 upstream of the refrigerant suction chamber 7, and directly controls the amount of refrigerant flowing into the refrigerant suction chamber 7. And a flow rate control valve drive mechanism 32 that drives and controls the flow rate control valve 31.
[0029]
The flow control valve 31 stores a spool valve 33 arranged orthogonal to the low-pressure side refrigerant passage 25, a spring 34 that urges the spool valve 33 in the valve closing direction, and a pressure that causes the spool valve 33 to act in the valve opening direction. And a pressure chamber 35.
[0030]
Both side surfaces 36a, 36b of the spool groove 36 of the spool valve 33 have the same pressure receiving area.
[0031]
The spring chamber 37 in which the spring 34 is accommodated communicates with the refrigerant suction chamber 7 side downstream of the flow rate control valve 31 of the low-pressure side refrigerant passage 25 by a passage 38.
[0032]
The flow rate control valve drive mechanism 32 is provided in a passage 40 that connects the refrigerant discharge chamber 8 and the pressure chamber 35, and serves as a pilot valve that controls the introduction of the high-pressure refrigerant in the refrigerant discharge chamber 8 into the pressure chamber 35 as an operating pressure. A ball valve 41 and a solenoid 42 for controlling the valve opening degree of the ball valve 41 according to the exciting current are provided.
[0033]
The ball valve 41 is normally seated on a valve seat by a spring 43 and closed.
[0034]
The solenoid 42 is configured to move the armature 44 upward in FIG. 2 when an excitation current is supplied and to push the plunger 45 to control the valve opening degree of the ball valve 41.
[0035]
The flow rate control valve drive mechanism 32 detects the pressure on the evaporator side upstream of the flow rate control valve 31 in the low pressure side refrigerant passage 25 and makes the pressure on the evaporator side variably controlled by the excitation current of the solenoid 42 constant. Feedback means 46 for holding is provided.
[0036]
The feedback means 46 is held by the diaphragm 47, a diaphragm 47 that separates the atmospheric pressure chamber 48 and the refrigerant pressure chamber 49, a feedback passage 50 that introduces the pressure on the evaporator side into the refrigerant pressure chamber 49, and the solenoid 42. Of the low pressure side refrigerant passage 25 when the ball valve 41 is controlled to a predetermined opening degree. When the pressure on the evaporator side changes from a certain pressure, the change in pressure is detected 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 degree of the flow control valve 31 is increased. By adjusting, the pressure on the evaporator side is kept constant.
[0037]
The refrigerant pressure chamber 49 is communicated with the crank chamber 5 through a pressure adjusting passage 52, and the crank chamber 5 is communicated with the evaporator side upstream of the flow rate control valve 31 in the low-pressure side refrigerant passage 25.
[0038]
In addition, a pressure adjusting passage 53 communicating with the refrigerant suction chamber 7 is communicated with the downstream side of the ball valve 41 of the passage 40 communicating with the pressure chamber 35 of the flow control valve 31, and the pressure adjusting passage 53 allows The pressure chamber 31 and the refrigerant suction chamber 7 are communicated with each other.
[0039]
Further, the flow control valve drive mechanism 32 is provided with a high-pressure side refrigerant introduction passage 54 that allows the refrigerant discharge chamber 8 and the feedback passage 50 to communicate with each other when the low-pressure side refrigerant passage 25 is fully closed by the spool valve 33. .
[0040]
In this embodiment, as shown also in FIG. 3, the plunger 51 held in the diaphragm 47 of the feedback means 46 is formed hollow, and the high-pressure side refrigerant introduction passage 54 is configured by the plunger 51.
[0041]
At the upper end of the plunger 51, a communication hole 55 is provided at an appropriate portion facing the refrigerant pressure chamber 49. When the ball valve 41 is opened, the tip opening of the plunger 51 is blocked by the ball valve 41. Further, the length is set such that the tip opening is opened when the ball valve 41 is fully closed, and 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 are opened. 50 through the refrigerant pressure chamber 49.
[0042]
According to the structure of the above embodiment, when the solenoid 42 is excited, the valve opening degree 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 passes through the passage 40. Is introduced into the pressure chamber 35 of the flow control valve 31 as an operating pressure.
[0043]
In response to the pressure in the pressure chamber 35, the spool valve 33 moves in a direction to open against the spring force of the spring 34, and expands the flow path of the low-pressure side refrigerant passage 25 to supply refrigerant to the refrigerant suction chamber 7. By controlling the inflow amount, adjusting the differential pressure between the refrigerant suction chamber 7 and the crank chamber 5 to control the inclination angle of the swash plate 15, and changing the stroke of the piston 18 to control the refrigerant discharge amount. The temperature of the outside evaporator is controlled.
[0044]
Here, for the purpose of preventing the evaporator from freezing during the operation of the refrigeration cycle, the refrigerant flow rate into the refrigerant suction chamber 7 is set to 0, and the pressure drop on the evaporator side upstream of the flow rate control valve 31 in the low-pressure side refrigerant passage 25 In order to stop, the supply current to the solenoid 42 is set to 0 and the solenoid 42 is demagnetized. The demagnetization of the solenoid 42 closes the ball valve 41 and the operating pressure to the pressure chamber 35 of the flow control valve 31 is reduced. Since the supply is stopped, the spool valve 33 is closed by the spring force of the spring 34 to block the low-pressure side refrigerant passage 25, the refrigerant inflow amount to the refrigerant suction chamber 7 is set to 0, and the inclination angle of the swash plate 15 is increased. By controlling, the piston stroke is reduced and the decrease in the evaporator-side pressure of the low-pressure side refrigerant passage 25 is stopped to prevent the evaporator from freezing.
[0045]
In this manner, when the evaporator is prevented from freezing, the supply of the excitation current to the solenoid 42 only has to be stopped, so that power consumption can be reduced and the load on the compressor can be substantially reduced by the fully closed operation of the spool valve 33. Therefore, the output of the drive source can be improved.
[0046]
As described above, when the supply of the excitation current to the solenoid 42 is stopped and the spool valve 33 of the flow control valve 31 is operated to close, the pressure in the refrigerant suction chamber 7 drops, and the cylinder internal pressure and the crank chamber 5 In order to make the compression work of the compressor almost zero by setting the inclination of the swash plate 15 by the moment around the pin 17 and minimizing the stroke of the piston 18, the compression by the excitation and demagnetization of the solenoid 42 is performed. The operation of the machine can be interrupted / interrupted, and the clutch that used to interrupt the transmission of the drive to the compressor can be abolished, making it a so-called clutchless. For example, in the case of an electromagnetic clutch, a heavy magnet, A coil or the like can be eliminated.
[0047]
Therefore, the structure of the compressor can be simplified, the size and weight can be reduced, and the wiring for energizing the clutch can be eliminated, and the cost can be advantageously obtained.
[0048]
Further, when a predetermined excitation current is supplied to the solenoid 42 of the flow control valve mechanism 32 and the ball valve 41 is set to a predetermined opening degree, when the vehicle is suddenly accelerated or decelerated, the low-pressure side refrigerant passage is caused by fluctuations in the rotational speed of the compressor. The pressure on the evaporator side upstream of the 25 flow control valve 31 changes, but this change in pressure is immediately detected by the diaphragm 47 of the feedback means 46 and the ball valve 41 is moved in the valve closing direction or valve opening direction via the plunger 51. When operated, the evaporator side pressure can be maintained at a constant pressure commensurate with the excitation current of the solenoid 42, so that fluctuations in the evaporator control temperature due to sudden acceleration and deceleration of the vehicle can be avoided.
[0049]
In such an antifreezing operation of the evaporator, that is, in a state where 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 valve 41 is closed, the high-pressure side refrigerant introduction passage 54 of the plunger 51 is opened, the refrigerant discharge chamber 8 and the feedback passage 50 communicate with each other, and the high-pressure to the evaporator side of the low-pressure side refrigerant passage 25 passes through the feedback passage 50. Since the side refrigerant is introduced to increase the pressure on the evaporator side, the evaporator can be reliably prevented from freezing even if the refrigerant leaks from the spool valve 33 to the refrigerant suction chamber 7.
[0050]
In particular, in the present embodiment, the high-pressure side refrigerant introduction passage 54 is constituted by the plunger 51 itself held by the diaphragm 47 of the feedback means 46, and its opening / closing control is performed by the ball valve 41. In addition, the control valve setting is not required, the structure can be simplified, and the cost can be advantageously obtained.
[0051]
Here, since both side surfaces 36a and 36b of the spool groove 36 provided in the spool valve 33 of the flow rate control valve 31 have the same pressure receiving area, the spring of the spring 34 that urges the spool valve 33 in the valve closing direction. Only by managing the force and the operating pressure acting on the pressure chamber 35, the accuracy of the opening / closing stroke of the spool valve 33 can be obtained, and the flow rate control with high accuracy can be performed.
[0052]
Further, the crank chamber 5 communicates with the evaporator side upstream of the flow rate control valve 31 of the low pressure side refrigerant passage 25 by the pressure adjusting passage 52 and is kept constant at the same pressure. Thus, the accuracy of variable capacity control can be improved.
[0053]
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, when the ball valve 41 is closed by demagnetization of the solenoid 42 of the flow control valve drive mechanism 32, Since the operating pressure of the pressure chamber 35 can be quickly released to the refrigerant suction chamber 7 side and the spool valve 35 can be closed, responsiveness can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of the present invention.
FIG. 2 is an explanatory cross-sectional view systematically showing pressure adjusting means in the embodiment.
FIG. 3 is an enlarged view showing a configuration of a high-pressure side refrigerant introduction passage.
[Explanation of symbols]
5 Crank chamber 7 Refrigerant suction chamber 8 Refrigerant discharge chamber 25 Low pressure side refrigerant passage 30 Pressure adjusting means 31 Flow rate control valve 32 Flow rate 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 passage 51 Plungers 52, 53 Pressure adjustment passage 54 High-pressure side refrigerant introduction passage

Claims (5)

In the swash plate type variable displacement compressor provided with pressure adjusting means (30) for adjusting the pressure of the refrigerant suction chamber (7) and the crank chamber (5) by controlling the flow rate of the refrigerant flowing into the refrigerant suction chamber (7).
The pressure adjusting means (30) accumulates a spool valve (33), a spring (34) for urging the spool valve (33) in the valve closing direction, and a pressure for operating the spool valve (33) in the valve opening direction. A flow rate control valve (31) provided in the low-pressure side refrigerant passage (25) upstream of the refrigerant suction chamber (7),
It is provided in a passage (40) communicating with the refrigerant discharge chamber (8) and the pressure chamber (35), and is normally closed by a spring (43), and is opened by an excitation current of a solenoid (42). And a flow rate control valve drive mechanism (32) having a pilot valve (41) that controls the introduction of the high-pressure side refrigerant in the refrigerant discharge chamber (8) into the pressure chamber (35) as an operating pressure,
The flow rate control valve drive mechanism (32) includes a flow rate control valve for the low-pressure side refrigerant passage (25) introduced via the feedback passage (50) when the pilot valve (41) is in a predetermined opening state. When the pressure on the upstream evaporator side changes from a certain pressure, this change in pressure is detected by the diaphragm (47), and the pilot valve (41) is moved via the plunger (51) held by the diaphragm (47). The spool valve (33) is provided with feedback means (46) that operates in the valve closing direction or valve opening direction, adjusts the valve opening degree of the flow rate control valve (31), and keeps the pressure on the evaporator side constant. A high-pressure side refrigerant introduction passage (54) that communicates between the refrigerant discharge chamber (8) and the feedback passage (50) when the low-pressure side refrigerant passage (25) is fully closed. Swash plate type variable displacement compressor according to. The plunger (51) is formed hollow, and when the pilot valve (41) is opened, the tip opening is closed by the pilot valve (41), and when the pilot valve (41) is fully closed. 2. The swash plate type variable capacity compressor according to claim 1, wherein the swash plate type variable capacity compressor is set to a length at which the front end opening is opened, and the high-pressure side refrigerant introduction passage (54) is configured by the hollow plunger (51). The swash plate type variable capacity compressor according to claim 1 or 2, wherein the spool valve (33) has equal pressure receiving areas on both sides of the spool groove (36). The flow control valve drive mechanism (32) includes a pressure adjustment passage (52) that communicates the crank chamber (5) with the evaporator side upstream of the flow control valve (31) of the low-pressure side refrigerant passage (25). The swash plate type variable capacity compressor according to any one of claims 1 to 3. The flow rate control valve drive mechanism (32) includes a pressure adjusting passage (53) that communicates the pressure chamber (35) of the flow rate control valve (31) and the refrigerant suction chamber (7). The swash plate type variable capacity compressor in any one of 1-4.

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