JP2005076514A - Variable displacement compressor and method for controlling displacement - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable displacement compressor capable of changing displacement at high response by reducing influence of friction force acting on a variable displacement mechanism, and a method for controlling the same. <P>SOLUTION: This compressor is constructed to change displacement by changing pressure in a crank case 16 for operating and regulating a variable displacement mechanism 20. When displacement is changed, an air-conditioner ECU applies tilting force exceeding friction force acting on the mechanism on the variable displacement mechanism 20, changes and controls pressure in the crank case 16. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a variable capacity compressor used for, for example, a vehicle air conditioner and a capacity control method thereof.

  Conventionally, as a variable capacity compressor, one having a capacity changing mechanism including a swash plate or the like in a crank chamber of a housing is known. And by increasing or decreasing the opening of the electromagnetic control valve, the pressure in the crank chamber is changed, the inclination angle of the swash plate of the capacity changing mechanism is adjusted, and the reciprocating stroke of the piston linked to this swash plate is changed. The gas discharge capacity is adjusted.

  In the variable capacity compressor having such a configuration, in order to improve the power conversion efficiency, a drive current having a high frequency of about 400 Hz is supplied to the electromagnetic coil of the electromagnetic control valve. Then, by controlling the supplied drive current by pulse width modulation, the position in the opening and closing direction of the valve body is determined by the balance between the magnetic attractive force generated by the electromagnetic coil and the spring force of the valve spring. The valve opening is controlled in accordance with the position of the valve body.

  In the control of the electromagnetic control valve, the amplitude of the coil current flowing through the electromagnetic coil becomes smaller as the frequency of the supply current is higher. The magnetic attractive force generated by the electromagnetic coil is determined by the number of values obtained by multiplying the number of coil turns and the coil current value. If the amplitude of the coil current is small, the amount of magnetic attraction force in response to the pulse width modulation frequency is also small, and the vibration of the valve body is reduced or no longer vibrates. As a result, hysteresis occurs in the operation of the control valve mainly due to the frictional resistance acting on the valve body, making it difficult to control the electromagnetic control valve with high responsiveness.

In order to cope with such problems in the control of the electromagnetic control valve, for example, an electromagnetic control valve as disclosed in Patent Document 1 has been conventionally proposed. That is, in this conventional configuration, the natural frequency Fo of the spring / mass system has a pulse width so that the spring / mass system including the valve body and the valve spring generates a resonance phenomenon under energization control by pulse width modulation of the electromagnetic coil. The modulation frequency Fd is set to be in the range of 0.75 × Fd ≦ Fo ≦ 2.0 × Fd.
JP 2002-267039 A

  In the electromagnetic control valve described in Patent Document 1, the valve body is vibrated by the resonance phenomenon described above under energization control by pulse width modulation of the electromagnetic coil. For this reason, even if the fluctuation width of the coil current is small, the valve body operates while vibrating, so the static frictional force of the frictional resistance is reduced, and the opening degree of the valve body is stably changed with high responsiveness. Become so.

  However, in the variable capacity compressor provided with a movable mechanical capacity changing mechanism including a swash plate or the like in the crank chamber as described above, not only friction resistance is added to the valve body moving portion of the electromagnetic control valve, A large frictional resistance also acts on the operating portion of the capacity changing mechanism. For example, in a variable capacity compressor in which a drive shaft is provided with a swash plate as a capacity changing mechanism, a large frictional resistance acts on a shaft support portion of the swash plate with respect to the drive shaft, a linkage portion of the swash plate with respect to the lug plate, and the like.

  For this reason, even when the opening of the electromagnetic control valve is changed with high responsiveness when changing the discharge capacity, the operation is not adjusted immediately due to frictional resistance in the capacity changing mechanism including the swash plate. There was a delay in changing the discharge capacity. For example, as shown in FIG. 8, in a state where the variable displacement compressor is operated at a predetermined discharge capacity G, the swash plate is stationary at a predetermined inclination angle. In this state, in order to change the discharge capacity, the supply current I to the electromagnetic coil of the electromagnetic control valve (in FIG. 8, the average of the supply current subjected to pulse width modulation is described) corresponds to the capacity change. Only increased or decreased.

  However, in the current increase / decrease control corresponding to the capacity change, the change in the pressure in the crank chamber (the pressure Pc in the crank chamber) is slow, so the upper limit due to the static friction force that the pressure Pc in the crank chamber acts on the swash plate It takes time to exceed PcH or the lower limit PcL. For this reason, the discharge capacity G is not changed in response to the increase / decrease in the supply current I, and a response delay D occurs.

  Therefore, with a conventional variable capacity compressor, the capacity cannot be changed immediately in response to a change in the cooling load, and after the room has become quite hot, the capacity has increased and the cooling capacity has been increased, or the room has cooled considerably. The cooling capacity is reduced, and so-called unpleasant hunting may continue without stopping.

  Further, in the conventional variable capacity compressor, even in the process of changing the discharge capacity, that is, in the process of changing the inclination angle of the swash plate, the dynamic friction acting on the operating portion of the capacity changing mechanism including the swash plate and the like. Due to the force, there was a delay in changing the discharge capacity. That is, as shown in FIG. 9A, when the supply current I to the electromagnetic coil of the electromagnetic control valve is lowered or raised, as shown in FIG. While the pressure Pc and the intake pressure Ps in the crank chamber are lowered or raised, the discharge pressure Pd is raised or lowered. As a result, as shown in FIG. 9C, the discharge capacity G and the output torque Tr of the compressor are lowered or raised.

  Here, the pressure Pc and the discharge capacity G in the crank chamber are compared at times T1 and T2 indicating the same current value Ia when the supply current I is decreasing and when it is increasing. As shown in FIGS. 9B and 9C, at time points T1 and T2, the pressure Pc in the crank chamber becomes Pc1 and Pc2, and the discharge capacity G becomes G1 and G2, respectively. There is a difference, and in particular, there is a large difference S in the discharge capacity G. That is, since the current value Ia is the same at time points T1 and T2, the pressures Pc1 and Pc2 and the discharge capacities G1 and G2 in the crank chamber should be the same. The reason why these are not the same is that the dynamic friction force acts on the capacity changing mechanism in operation, and the pressures Pc1, Pc2 in the crank chamber and the discharge capacities G1, G2 are delayed with respect to the change in the current value Ia. As described above, the dynamic friction force also causes a delay in capacity change corresponding to the cooling load.

  The present invention has been made paying attention to such problems existing in the prior art. Its main object is to provide a variable capacity compressor and a control method capable of changing the discharge capacity with high responsiveness without being affected by the static friction force acting on the capacity changing mechanism.

  Another object of the present invention is to provide a variable capacity compressor and a control method capable of suppressing a response delay caused by a dynamic friction force acting on the capacity changing mechanism during the change of the discharge capacity. There is.

  In order to achieve the above object, an invention according to claim 1 is provided with a control valve having an electromagnetic actuator, and by controlling the drive current for the electromagnetic actuator from the outside to change the valve opening, In a variable capacity compressor that can change the discharge capacity by mechanically operating the capacity change mechanism in the crank chamber and changing the discharge capacity, the pressure in the crank chamber is changed when the discharge capacity is changed. As described above, control means for performing control to superimpose a fluctuation current of a predetermined pattern on the drive current is provided.

  According to a second aspect of the present invention, in the first aspect of the present invention, the control valve includes a sensing mechanism for sensing a cooling load, and the sensing mechanism opens the valve according to the cooling load. To change the degree.

According to a third aspect of the present invention, in the first aspect of the present invention, the control valve changes the valve opening degree only by external control of the drive current.
The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the capacity changing mechanism changes the inclination angle of the swash plate for reciprocating the piston, The capacity is changed.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the fluctuation current of the predetermined pattern is constantly superimposed.
According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the fluctuation current of the predetermined pattern is a pulsating flow having a regular amplitude.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the fluctuation current of the predetermined pattern is changed after the magnitude of the drive current supplied to the control valve is changed. Superposed for a predetermined time.

The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein the control of the drive current for changing the valve opening is performed by pulse width modulation.
The invention according to claim 9 relates to a capacity control method for a variable capacity compressor, comprising a control valve having an electromagnetic actuator, and changing the valve opening by controlling the drive current for the electromagnetic actuator from the outside. Thus, in a variable capacity compressor that changes the pressure in the crank chamber and mechanically operates the capacity changing mechanism in the crank chamber to change the discharge capacity, the drive current is changed when the discharge capacity is changed. The pressure in the crank chamber is changed by superimposing a predetermined pattern of fluctuation current on the cylinder.

According to a tenth aspect of the present invention, in the ninth aspect of the invention, the fluctuation current of a predetermined pattern is always superimposed.
According to an eleventh aspect of the present invention, in the invention according to the tenth aspect, the fluctuation current of the predetermined pattern is a pulsating flow having a regular amplitude.

According to a twelfth aspect of the present invention, in the ninth aspect of the invention, the fluctuation current of the predetermined pattern is superimposed for a predetermined time after the magnitude of the drive current supplied to the control valve is changed.
(Function)
In the first and ninth aspects of the invention, the pressure in the crank chamber is controlled to vary when the discharge capacity is changed. Therefore, the influence of the frictional force acting on the capacity changing mechanism can be suppressed, and therefore, the discharge capacity can be changed with high responsiveness without causing a response delay of the capacity changing mechanism when the discharge capacity is changed. it can.

  In the second aspect of the present invention, since the pressure in the crank chamber fluctuates, the capacity changing mechanism is changed even if the capacity change is slight when the sensing mechanism changes the valve opening to change the capacity. It can be reliably operated with high responsiveness.

In the invention described in claim 3, since there is no sensing mechanism, the configuration is simple and the same effect as in claim 1 can be obtained.
In the invention described in claim 4, the capacity changing mechanism in the crank chamber includes a swash plate, and the capacity is changed by changing the inclination angle of the swash plate. Therefore, the pressure fluctuation in the crank chamber immediately acts on the swash plate, and the capacity can be changed with high responsiveness.

  In the inventions according to the fifth and tenth aspects, as a configuration for superimposing the fluctuation current on the drive current, a function for generating the fluctuation current at the timing is unnecessary, and the configuration is simplified. In addition, the crank chamber pressure fluctuates even during the capacity change. Therefore, the influence of the dynamic friction force in the capacity changing mechanism can be reduced, and the discharge capacity changing control can be performed with good responsiveness. Furthermore, since the pressure in the crank chamber is constantly changing, the capacity change mechanism can be reliably and highly responsive when the sensing mechanism changes the valve opening to change the capacity even if the capacity change is slight. Can be operated.

  In the inventions according to the sixth and eleventh aspects, the pressure in the crank chamber constantly fluctuates constantly and the fluctuation constantly acts on the swash plate. Therefore, the capacity change is performed by a slight discharge capacity change command. It can be executed with high responsiveness.

  In the inventions according to claims 7 and 12, the magnitude of the drive current supplied to the control valve is changed, and after a predetermined time has elapsed since the change, the pressure fluctuation in the crank chamber is stopped. Unnecessary capacity change can be prevented.

  In the invention according to the eighth aspect, vibration is imparted to the valve body in the control valve, so that hysteresis (response delay) in the operation of the valve body can be reduced, thereby contributing to accurate capacity control.

  As described above, according to the present invention, the influence of the static friction force acting on the capacity changing mechanism can be suppressed, the discharge capacity can be changed with high responsiveness, and comfortable air conditioning can be executed.

(First embodiment)
Below, 1st Embodiment of this invention is described based on FIGS. 1-4.
First, the configuration of the variable capacity compressor will be described. As shown in FIG. 1, the compressor housing 11 includes a cylinder block 12 having a plurality of cylinder bores 12a, a front housing 13 joined and fixed to the front side across the cylinder block 12, and a valve plate. 15 and a rear housing 14 joined and fixed to the rear side through 15.

  Inside the rear housing 14, a suction chamber 14a and a discharge chamber 14b are defined. A suction valve 15a is formed on the valve plate 15 so as to be positioned between each cylinder bore 12a and the suction chamber 14a, and a discharge valve 15b is formed so as to be positioned between each cylinder bore 12a and the discharge chamber 14b. Has been. A crank chamber 16 is formed in the front housing 13 with the rear side closed by the cylinder block 12. A drive shaft 17 is rotatably supported on the front housing 13 and the cylinder block 12 via a pair of radial bearings 18 so as to penetrate the crank chamber 16.

  A lug plate 19 is fixed to the drive shaft 17 in the crank chamber 16 so as to be integrally rotatable. On the rear side of the lug plate 19, a swash plate 21 constituting a capacity changing mechanism 20 is supported on the drive shaft 17 so as to be slidable and tiltable in the axial direction of the drive shaft 17. A hinge mechanism 22 is interposed between the swash plate 21 and the lug plate 19, and the swash plate 21 is operatively connected to the lug plate 19 and the drive shaft 17 so as to be capable of synchronous rotation and tilting via the hinge mechanism 22. Has been.

  A stopper portion 21a protrudes from the front portion of the swash plate 21, and the maximum tilt angle position of the swash plate 21 is regulated by the stopper portion 21a coming into contact with the lug plate 19 as shown by a solid line in FIG. It has become so. A circlip 23 is attached to the drive shaft 17 on the rear side of the swash plate 21, and as shown by a chain line in FIG. Being regulated.

  In each cylinder bore 12 a of the cylinder block 12, a single-headed piston 24 is accommodated so as to be able to reciprocate, and the neck portion of the piston 24 is anchored to the outer periphery of the swash plate 21 via a shoe 25. When the swash plate 21 is rotationally moved along with the rotation of the drive shaft 17, each piston 24 is reciprocated via the shoe 25. Thereby, when each piston 24 is moved from the top dead center position to the bottom dead center side, the refrigerant gas in the suction chamber 14a is sucked into the compression chamber 26 in the cylinder bore 12a via the suction valve 15a. Thereafter, when each piston 24 is moved from the bottom dead center position to the top dead center side, the refrigerant gas in the compression chamber 26 is compressed to a predetermined pressure and discharged to the discharge chamber 14b via the discharge valve 15b. It is like that.

  A bleed passage 27 is formed in the cylinder block 12 and the like so as to communicate the crank chamber 16 and the suction chamber 14a. The bleed passage 27 is formed in an axial passage 27 a formed so as to pass from the outer periphery of the end of the drive shaft 17, a recess 27 b formed in the center of the rear portion of the cylinder block 12, and a rear surface of the cylinder block 12. The pressure release passage 27c is formed with a pressure release hole 27d formed in the valve plate 15. The refrigerant gas is led out from the crank chamber 16 to the suction chamber 14a through the extraction passage 27.

  An air supply passage 28 is formed in the cylinder block 12, the valve plate 15, and the rear housing 14 so that the discharge chamber 14 b and the crank chamber 16 communicate with each other. A capacity control valve 29 is disposed in the rear housing 14 so as to be located in the middle of the air supply passage 28. The amount of high-pressure refrigerant gas introduced from the discharge chamber 14b into the crank chamber 16 through the air supply passage 28 is determined by adjusting the valve opening of the capacity control valve 29. For this reason, the balance between the amount of refrigerant gas introduced into the crank chamber 16 and the amount of refrigerant gas led out from the crank chamber 16 to the suction chamber 14a via the extraction passage 27 is controlled. The pressure is determined. As a result, the difference between the pressure in the crank chamber 16 and the pressure in the compression chamber 26 sandwiching the piston 24 is changed, the inclination angle of the swash plate 21 is changed, and the stroke of the piston 24, that is, the discharge of the compressor. The capacity is adjusted.

Next, the configuration of the capacity control valve 29 will be described.
As shown in FIG. 2, a valve chamber 32, a communication path 33, and a pressure sensing chamber 34 are defined in the valve housing 31. As shown in FIGS. 1 and 2, the valve chamber 32 communicates with the discharge chamber 14 b via the upstream portion of the air supply passage 28, and the communication passage 33 communicates with the crank chamber via the downstream portion of the air supply passage 28. 16 is communicated. The pressure sensitive chamber 34 communicates with the suction chamber 14 a via a pressure sensitive passage 35 formed in the rear housing 14.

  An operating rod 36 is disposed in the valve chamber 32 and the communication passage 33 of the valve housing 31 so as to be movable in the axial direction. The upper end portion of the operation rod 36 establishes a gap between the communication passage 33 and the pressure sensing chamber 34. Shielded. A valve body portion 37 is formed at an intermediate portion of the operating rod 36 so as to be located in the valve chamber 32, and the valve chamber 32, the communication passage 33, and the upper end of the valve body portion 37 can be connected to and separated from each other. A valve seat 38 is provided at the boundary. Then, when the operating rod 36 is moved in its own axial direction, the valve opening degree of the valve body 37 with respect to the valve seat 38 is changed, and the degree of opening of the air supply passage 28 is adjusted. .

  A pressure sensitive member 39 made of a bellows as a sensing mechanism for sensing a cooling load is disposed in the pressure sensitive chamber 34 of the valve housing 31, and an upper end portion of an operating rod 36 is provided at the bottom of the pressure sensitive member 39. Is fixed. A pressure-sensitive member urging spring 40 is disposed in the pressure-sensitive member 39, and the pressure-sensitive member 39 is urged by the spring 40 in the downward extending direction of FIG. Then, during operation of the compressor, the pressure sensitive member 39 according to the intake pressure Ps of the suction chamber 14a acting on the pressure sensitive member 39 in the pressure sensitive chamber 34 via the pressure sensitive passage 35, that is, according to the cooling load. Is expanded or contracted, whereby the position of the actuating rod 36 is changed, and the valve opening degree of the valve body 37 with respect to the valve seat 38 is adjusted autonomously internally.

  An electromagnetic actuator 41 is connected to the lower portion of the valve housing 31. In the center of the casing 42 of the electromagnetic actuator section 41, a bottomed cylindrical housing cylinder 43 is disposed. A cylindrical fixed iron core 44 is fitted into the upper portion of the housing cylinder 43, and the lower end portion of the operating rod 36 is movably inserted into the fixed iron core 44. A movable iron core 45 is movably accommodated in the lower part of the accommodating cylinder 43 so as to be able to contact and separate from the fixed iron core 44. A movable core biasing spring 46 is interposed between the inner bottom portion of the housing cylinder 43 and the movable core 45, and the movable core 45 is biased by the spring 46 in a direction in which the movable core 45 is joined to the lower end surface of the operating rod 36. Yes.

  A coil 47 is wound around the outer periphery of the housing cylinder 43 so as to straddle between the fixed iron core 44 and the movable iron core 45. The coil 47 is supplied with a drive current I from an air conditioner ECU 49 constituting a control means via a valve drive circuit 50 (hereinafter referred to as a supply current). As the supply current I, for example, a high-frequency current or a direct current with a high frequency of about 400 Hz (Hertz) is used. Then, by this pulse width modulation control of the high frequency current or the current value control of the direct current, the magnetic attractive force generated in the coil 47 of the electromagnetic actuator unit 41 is changed according to the current value. As a result, the position of the operating rod 36 is changed by the balance between the suction force and the spring force of the biasing spring 46, and the valve opening degree of the valve body portion 37 with respect to the valve seat 38 is adjusted. As a result, the pressure Pc in the crank chamber 16 is adjusted, the inclination angle of the swash plate 21 of the capacity changing mechanism 20 is changed, and the discharge capacity of the compressor is changed and controlled.

  In this embodiment, as described above, a high frequency current of about 400 Hz is supplied to the coil 47, the duty ratio of the high frequency current is controlled, and the strength of the magnetic force generated in the coil 47 is adjusted. The adjustment of the valve opening described above is executed by the adjustment, and the pressure in the crank chamber 16 is set. In this embodiment, a pulsating flow I1 having a pattern having a predetermined regular amplitude of about 5 to 30 Hz is constantly superimposed on the high-frequency current. Details of these will be described later.

  In the variable capacity compressor configured as described above, when the swash plate 21 of the capacity changing mechanism 20 is in a stationary state with a predetermined inclination angle, the lug plate 19 is a shaft support for the drive shaft 17 of the swash plate 21. A large static friction force acts between the swash plate 21 and its peripheral mechanisms, such as a linkage portion via the hinge mechanism 22 against the swash plate, and a particularly large static friction force acts on the contact portion between the swash plate 21 and the drive shaft 17. Yes. For this reason, in order for the swash plate 21 to tilt from this stationary state, it is necessary to apply a force that overcomes the static friction force to the swash plate 21.

  Here, in this embodiment, as shown in FIGS. 3 (a) and 4 (a), 400 Hz is applied to the coil 47 of the electromagnetic actuator unit 41 during the operation of the compressor including when the discharge capacity is changed. A supply current I having a high frequency is generated by the air conditioner ECU 49 and supplied at a required duty ratio (FIG. 3 (a) and FIG. 4 (a) α region). Accordingly, the supply current I is controlled from the outside of the control valve 29. As shown in FIGS. 3B and 4B, the supply current I has a predetermined frequency between 5 and 30 Hz generated by the air conditioner ECU 49, that is, a predetermined regular amplitude pattern. The pulsating flow I1 which is a fluctuation current is always superimposed. For this reason, the operating rod 36 always reciprocates in small increments with a period of 5 to 30 Hz. Accordingly, the degree of opening of the air supply passage 28 constantly varies periodically, and the pressure Pc in the crank chamber 16 also varies regularly.

  Here, as shown in FIG. 3 (c), when the compressor is operated at a predetermined discharge capacity G and the discharge capacity is lowered, as shown in the region β of FIG. 3 (a). In addition, the duty ratio of the supply current I to the coil 47 is increased. For this reason, the opening degree of the supply passage 28 is changed in the opening direction, and the pressure in the crank chamber 16 is increased. The increasing rate of the duty ratio is such that pressure exceeding the static friction force acting on the shaft support portion of the swash plate 21 with respect to the drive shaft 17 and the linkage portion with respect to the lug plate 19 via the hinge mechanism 22 acts on the swash plate 21. In addition, the pressure in the crank chamber 16 is increased. In this case, as described above, since the pressure Pc in the crank chamber 16 periodically fluctuates, even if the pressure in the crank chamber 16 slightly increases due to a slight increase in the duty ratio, the swash plate 21 Tilts over the static friction force. Therefore, as the duty ratio of the supply current I increases, the pressure Pc in the crank chamber 16 that fluctuates periodically rises immediately exceeding the upper limit PcH due to the static friction force. As a result, the discharge capacity G is decreased and changed according to the change in the supply current I without causing a response delay.

  Further, as shown in FIG. 4C, when the discharge capacity is increased in a state where the compressor is operated at a predetermined discharge capacity G, as shown in a region β in FIG. The duty ratio of the supply current I to the coil 47 is decreased. For this reason, the opening degree of the air supply passage 28 is changed in the closing direction, and the pressure in the crank chamber 16 is lowered. Here, the reduction rate of the duty ratio is such that the pressure exceeding the static friction force acting on the shaft support portion of the swash plate 21 with respect to the drive shaft 17 and the linkage portion with respect to the lug plate 19 via the hinge mechanism 22 acts on the swash plate 21. By the time, the pressure in the crank chamber 16 is reduced. Also in this case, since the pressure Pc in the crank chamber 16 periodically fluctuates, even if the pressure in the crank chamber 16 slightly decreases due to a slight decrease in the duty ratio, the swash plate 21 does not cause the static friction. Tilt to overcome power. Therefore, contrary to the above, due to the decrease in the duty ratio of the supply current I, the pressure Pc in the crank chamber 16 that fluctuates periodically is immediately lowered beyond the lower limit PcL due to the static friction force. As a result, the discharge capacity G is decreased and changed according to the change in the supply current I without causing a response delay.

  Further, in this type of variable capacity compressor, even in the process of changing the discharge capacity, the change in the discharge capacity is caused by the dynamic friction force acting on the shaft support portion, the linkage portion, etc. of the swash plate 21 described above. There may be a delay. However, in the compressor of this embodiment, since the pulsating flow I1 of 5 to 30 Hz is superimposed on the supply current I to the coil 47 as described above, the pressure Pc in the crank chamber 16 is constantly periodically changed. Fluctuation is controlled. Therefore, the swash plate 21 is smoothly tilted without being affected by the dynamic friction force so that the discharge capacity is changed without causing a response delay. That is, since the swash plate 21 is vibrated 5 to 30 times per second, the swash plate 21 is tilted by this vibration, and the influence of the dynamic friction force can be suppressed.

Therefore, according to this embodiment, the following effects can be obtained.
(1) In this variable capacity compressor, the air-conditioner ECU 49 causes the pressure in the crank chamber 16 to fluctuate constantly and constantly on the swash plate 21 by the pulsating flow I1 contained in the supply current I. Therefore, the influence of the frictional force acting on the capacity changing mechanism can be suppressed. For this reason, the capacity change can be executed with high responsiveness by a slight discharge capacity change command, that is, by changing the duty ratio. Further, in this variable capacity compressor, when the discharge capacity is changed by the air conditioner ECU 49, the pressure Pc in the crank chamber 16 is fluctuated and controlled, and the tilt power that overcomes the static friction force acting on the capacity change mechanism 20 is controlled. Is to be granted. For this reason, the influence of the static friction force with respect to the capacity | capacitance change mechanism 20 is excluded, discharge capacity can be changed with high responsiveness, and comfortable air conditioning is realizable.

  (2) In this control device, the pressure Pc in the crank chamber 16 is constantly changed periodically by the air conditioner ECU 49 during the operation of the compressor including when the discharge capacity is changed. For this reason, in the process of changing the discharge capacity, the influence of the dynamic friction force acting on the capacity changing mechanism 20 can be reduced, and the occurrence of a response delay in the capacity change can be suppressed.

  (3) In this control device, in the capacity control valve 29 provided with the electromagnetic actuator unit 41 for changing the pressure Pc in the crank chamber 16, a pulsating flow I1 of 5 to 30 Hz is superimposed on the supply current to the coil 47. Is done. For this reason, the operation rod 36 of the capacity control valve 29 is reciprocated in small increments. Therefore, the influence of the static frictional force and the dynamic frictional force on the operating rod 36 can be reduced, and the operating rod 36 can be operated in response to the change in the supply current. As a result, the pressure in the crank chamber 16 has a good responsiveness. It becomes possible to adjust.

  (4) The pressure-sensitive member 39 is expanded and contracted by the change in the intake pressure due to the change in the cooling load, and the valve opening degree of the valve body portion 37 is adjusted by the expansion and contraction of the pressure-sensitive member 39 to change the capacity. In this case, when the variation amount of the intake pressure Ps is small and the expansion / contraction amount of the pressure-sensitive member 39 is small, the change amount of the valve opening is small, and the force for varying the pressure in the crank chamber 16 is small. With this variable amount compressor, it is difficult to tilt the swash plate 21 by overcoming the forces of static friction and dynamic friction. On the other hand, in this embodiment, as described above, since the pressure in the crank chamber 16 constantly fluctuates, the static friction force and the dynamic friction force are overcome as in the case of the capacity change by changing the duty ratio, The capacity change is executed accurately.

  (5) Furthermore, since the pulsating flow I1 is constantly superimposed on the supply current I, it is not necessary to provide the air conditioner ECU 49 with a function for generating the pulsating flow I1 at an appropriate timing, and the configuration becomes simple. .

  (6) In addition, since the supply current I by pulse width modulation is applied to the coil 47 of the control valve 29, vibration is applied to the operating rod 36 having the valve body portion 37. For this reason, in the operation of the operating rod 36, response delay due to hysteresis can be avoided, and accurate capacity control can be realized with good responsiveness.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with a focus on differences from the first embodiment.

  As shown in FIG. 5, a valve chamber 62 and a communication path 63 are formed in the valve housing 61. The valve chamber 62 communicates with the discharge chamber 14 b through a passage 65, and the communication passage 63 communicates with the crank chamber 16 through a passage 64. An operation rod 66 is disposed in the valve chamber 62 and the communication passage 63 so as to be movable in the axial direction. A valve body portion 67 is integrally formed at the upper end of the operating rod 66 so as to be located in the valve chamber 62, and a valve seat 68 corresponding to the valve body portion 67 is formed at the boundary between the valve chamber 62 and the communication path 63. Is provided. The spring 69 applies a weak spring force in the direction in which the valve body 67 closes the valve seat 68 to the operating rod 66 via the spring receiver 70.

  An accommodation cylinder 73 is disposed at the center of the casing 72 of the electromagnetic actuator portion 71 below the valve housing 61. A fixed iron core 74 is fitted into the lower portion of the housing cylinder 73, and a movable iron core 75 is housed in the housing cylinder 73 so as to be capable of coming into contact with and separating from the stationary iron core 74. The spring 76 applies a relatively strong spring force to the movable iron core 75 in the direction in which the valve body 67 opens the valve seat 68. A supply current I is supplied to the coil 77 from the air conditioner ECU 49 constituting the control means via the valve drive circuit 50. As this supply current I, a direct current is adopted.

  Then, by the current value control of the direct current I, the magnetic attractive force generated in the coil 77 of the electromagnetic actuator unit 71 is changed according to the current value. As a result, the position of the operating rod 66 is changed by the balance between the suction force and the spring force of the spring 76, and the valve opening degree of the valve body 67 with respect to the valve seat 68 is adjusted. As a result, the pressure Pc in the crank chamber 16 is adjusted, the inclination angle of the swash plate 21 of the capacity changing mechanism 20 is changed, and the discharge capacity of the compressor is changed and controlled.

  In the second embodiment, the pulsating flow I1 is not superimposed on the supply current I. Then, as shown in FIGS. 6 and 7, the magnitude of the current value of the supply current I to the coil 47 is temporarily changed in a predetermined pattern only when the discharge capacity is changed under the control of the air conditioner ECU 49. The pressure Pc in the crank chamber 16 is controlled to vary. In other words, the fluctuation current of a predetermined pattern is superimposed on the supply current I for a predetermined time after the magnitude of the supply current I to the control valve 29 is changed.

  That is, as shown in FIG. 6, when the capacity is reduced in the compressor operating state, the supply is performed so that the pressure Pc in the crank chamber 16 immediately rises above the upper limit PcH due to the static friction force. The current I is temporarily made higher than the required value. After the swash plate 21 is tilted, the supply current I is returned to a required value.

  Further, as shown in FIG. 7, when the capacity of the compressor is increased, the supply current I is required so that the pressure Pc in the crank chamber 16 is immediately increased beyond the lower limit PcL due to the static friction force. Temporarily lower than the value. Then, after the swash plate 21 is tilted, the supply current I is returned to a required value in the same manner as described above.

As described above, the discharge capacity is changed without causing a response delay according to the increase change of the supply current I.
Therefore, according to the second embodiment, as in the first embodiment, the pressure Pc in the crank chamber 16 is controlled to fluctuate so that the capacity change mechanism 20 can overcome the static friction force acting on the mechanism. Power is applied, the discharge capacity can be changed with high responsiveness, and comfortable air conditioning can be realized. Furthermore, in the second embodiment, the following effects can be obtained.

  (7) In the second embodiment, since there is no sensing mechanism including the pressure-sensitive member 39, the configuration is simple. Further, since the supply current I is returned to a predetermined value after a certain time from the capacity change and the capacity change is stopped, an unnecessary capacity change can be prevented.

(Example of change)
In addition, this embodiment can also be changed and embodied as follows.
In each of the above embodiments, the capacity control valve 29 is an intake pressure type that can adjust the valve opening degree autonomously based on the intake pressure Ps. Use a discharge pressure type valve whose valve opening can be adjusted autonomously based on the pressure Pd.

  In each of the above-described embodiments, the capacity control valve 29 is configured such that the valve opening degree can be adjusted autonomously inside, but the valve is changed only by electric control from outside. Use an electromagnetic control valve that adjusts the opening.

  In the above embodiment, the capacity control valve 29 is used as a so-called inlet control valve that changes the pressure Pc in the crank chamber 16 by introducing the discharge pressure by adjusting the opening of the air supply passage 28. On the other hand, it should be used as a so-called vent side control valve that adjusts the amount of extraction by adjusting the opening degree of the extraction passage 27 and changes the pressure Pc in the crank chamber 16.

-In the said embodiment, although the thing of the swash plate type provided with the swash plate 21 is used as the capacity | capacitance change mechanism 20, changing this to a wobble type thing.
In the embodiment, a current of about 400 Hz is used as the supply current I. However, the frequency is appropriately changed or a direct current is used.

  A discharge pressure is detected by a sensor (not shown), and the value of the pulsating flow I1 of the first embodiment or the value of the supply current I of the second embodiment is temporarily changed in accordance with the discharge pressure. Configure the plate 21 to tilt.

  In the first embodiment, by changing the duty ratio of the pulsating flow I1, the amplitude of the pulsating flow I1 is changed, whereby the value of the supply current I is temporarily changed to tilt the swash plate 21. Configure as follows.

Sectional drawing which shows the variable capacity compressor of 1st Embodiment. Sectional drawing which expands and shows the capacity | capacitance control valve of the variable capacity compressor of FIG. (A), (b), and (c) are graphs showing changes over time in the supply current to the capacity control valve, the pressure in the crank chamber, and the discharge capacity when the discharge capacity is decreased and changed. (A), (b), and (c) are graphs showing changes over time in the supply current to the capacity control valve, the pressure in the crank chamber, and the discharge capacity when the discharge capacity is increased and changed. Sectional drawing which expands and shows the capacity | capacitance control valve of 2nd Embodiment. The variable capacity compressor of 2nd Embodiment WHEREIN: The graph which shows the change state of the supply current to a capacity | capacitance control valve, the pressure in a crank chamber, and discharge capacity in time when discharge capacity is decreased and changed. The graph which shows the change state of the supply current to the capacity control valve, the pressure in the crank chamber, and the discharge capacity over time when the discharge capacity is similarly increased and changed. The graph which shows the change state of the supply current to a capacity | capacitance control valve, the pressure in a crank chamber, and a discharge capacity with time in the case of decreasing and changing a discharge capacity in a conventional variable capacity compressor. (A), (b), and (c) show changes in the pressure in the crank chamber, the intake pressure, and the discharge pressure when the supply current to the capacity control valve is changed in the conventional variable displacement compressor, and the discharge The graph which shows the change state of a capacity | capacitance and output torque with time.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Housing, 12 ... Cylinder block, 14 ... Rear housing, 14a ... Suction chamber, 14b ... Discharge chamber, 16 ... Crank chamber, 17 ... Drive shaft, 19 ... Lug plate, 20 ... Capacity changing mechanism, 21 ... Swash plate, DESCRIPTION OF SYMBOLS 22 ... Hinge mechanism, 24 ... Piston, 25 ... Shoe, 26 ... Compression chamber, 28 ... Supply air passage, 29 ... Capacity control valve, 31 ... Valve housing, 36 ... Actuation rod, 37 ... Valve body part, 38 ... Valve seat , 39 ... Pressure-sensitive member, 41 ... Electromagnetic actuator section, 44 ... Fixed iron core, 45 ... Movable iron core, 47 ... Coil, 49 ... Air conditioner ECU constituting control means, I ... Supply current (drive current), I1 ... Pulse flow , Pc: pressure in the crank chamber, G: discharge capacity.

Claims (12)

A control valve having an electromagnetic actuator is provided, and by controlling the drive current to the electromagnetic actuator from the outside and changing the valve opening, the pressure in the crank chamber is changed and the capacity changing mechanism in the crank chamber is mechanically In a variable capacity compressor that can be operated and changed its discharge capacity,
A variable capacity compressor provided with a control means for performing control to superimpose a fluctuation current of a predetermined pattern on the driving current so that the pressure in the crank chamber is fluctuated when the discharge capacity is changed. The variable capacity compressor according to claim 1, wherein the control valve includes a sensing mechanism for sensing a cooling load, and the sensing mechanism changes a valve opening degree according to the cooling load. The variable capacity compressor according to claim 1, wherein the control valve changes the valve opening degree only by external control with respect to the drive current. The variable capacity compressor according to any one of claims 1 to 3, wherein the capacity changing mechanism changes the capacity by changing an inclination angle of a swash plate for reciprocating the piston. The variable capacity compressor according to any one of claims 1 to 4, wherein the fluctuation current of the predetermined pattern is constantly superimposed. The variable capacity compressor according to claim 5, wherein the fluctuation current of the predetermined pattern is a pulsating flow having a regular amplitude. The variable capacity compressor according to any one of claims 1 to 6, wherein the fluctuation current of the predetermined pattern is superimposed for a predetermined time after the magnitude of the drive current supplied to the control valve is changed. The variable capacity compressor according to any one of claims 1 to 7, wherein the control of the drive current for changing the valve opening is performed by pulse width modulation. A control valve having an electromagnetic actuator is provided, and by controlling the drive current to the electromagnetic actuator from the outside and changing the valve opening, the pressure in the crank chamber is changed and the capacity changing mechanism in the crank chamber is mechanically In a variable capacity compressor that can be operated and changed its discharge capacity,
A capacity control method for a variable capacity compressor, wherein when the discharge capacity is changed, a fluctuation current of a predetermined pattern is superimposed on the driving current to vary the pressure in the crank chamber. The variable capacity compressor capacity control method according to claim 9, wherein the fluctuation current of the predetermined pattern is constantly superimposed. The capacity control method for a variable capacity compressor according to claim 10, wherein the fluctuation current of the predetermined pattern is a pulsating flow having a regular amplitude. The variable capacity compressor capacity control method according to claim 9, wherein the fluctuation current of the predetermined pattern is superimposed for a predetermined time after the magnitude of the drive current supplied to the control valve is changed.

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