JP2004003468A - Variable displacement compressor having displacement control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable displacement compressor for improving a leading characteristic at the start by rapidly relieving a refrigerant in a crank chamber in an intake chamber. <P>SOLUTION: When the electromagnetic force of a displacement control valve 20 exceeds a predetermined value, a valve part 24b closes communication passages 66 and 68, and communication of a crank chamber with a discharge chamber is blocked. Since a refrigerant in the discharge chamber is not introduced in the crank chamber, a flow of the refrigerant from the crank chamber to the intake chamber via a variable orifice mechanism is generated. Since a large diameter part of a stepped part (a truncated conical part) integrated with an upper side of the valve part is detached from a hole in a partition 25, a space between the stepped part and the hole in the partition is increased. The variable orifice mechanism has the diameter necessary and sufficient for allowing a blow-by gas generated when compressing the refrigerant by a piston to flow in the intake chamber, and the pressure in the crank chamber is rapidly dropped, and equal to the pressure in the intake chamber. Therefore, the displacement of the compressor is maintained at a maximum value. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a variable displacement compressor having a displacement control valve, and is used as an example in an air conditioner for a vehicle.
[0002]
[Prior art]
A description will be given of a displacement control valve of a conventional variable displacement oscillating plate compressor (for example, see Patent Document 1).
[0003]
As shown in FIG. 5, a pressure-responsive valve 104 constituting a variable orifice is installed in the fitting hole 101a of the cylinder block 101. The pressure responsive valve 104 has a casing 105 in which four ports 105a, 105b, 105c, and 105d are drilled, and the casing 105 is fitted into the fitting hole 101a. The first port 105a communicates with the low-pressure chamber 122 via the communication hole 102a of the valve plate 102, the second port 105b communicates with the low-pressure chamber 122 via the first communication passage 111, and the third port 105c communicates with the second communication port. The fourth port 105 d communicates with the high-pressure chamber 123 via the third communication path 113 through the passage 112 and the inside of the crank chamber 121.
[0004]
Inside the casing 105, bellows 106 and 107 having a dual inner / outer structure are installed. One end of each of the bellows 106 and 107 is fixed to an inner surface of one end of the casing 105, and the other end is fixed to a flange-like member 109 protruding from a substantially intermediate portion of the rod-shaped valve body 108 in the axial direction. A coil spring 110 is interposed between a portion of the flange-like member 109 located between the bellows 106 and 107 and an inner surface of one end of the casing 105. The bellows 106 and 107 are urged by a coil spring 110 in the extension direction. The inner bellows 106 communicates with the high-pressure chamber 123 via the fourth port 105d and the third passage 113. The inside of the outer bellows 107 communicates with the low-pressure chamber 122 via the second port 105 b and the first communication passage 111. The inside of the casing 105 communicates with the inside of the crank chamber 121 via the third port 105 c and the second communication passage 112. The inside of the casing 105 communicates with the low-pressure chamber 122 via the first port 105a and the communication hole 102a of the valve plate 102.
[0005]
One end of the rod-shaped valve element 108 extends from the flange-shaped member 109 to the inside of the inner bellows 106, and has a head 108a at the extended end. When the pressure in the crank chamber 121 is low, the end face of the head 108a faces the opening end of the fourth port 105d on one inner face of the casing 105 with a predetermined gap L therebetween. The other end of the rod-shaped valve element 108 is slidably fitted in the first port 105a, and has a tapered head 108b at the other end corresponding to the tapered surface of the first port 105a. When the rod-shaped valve element 108 slides, the opening area between the tapered surface of the tapered head portion 108b and the tapered surface of the first port 105a changes.
[0006]
When the pressure in the crank chamber 121 is low, the bellows 106 and 107 extend by the action of the pressure introduced into the inner bellows 106 from the high-pressure chamber 123 through the third communication passage 113 and the fourth port 105d. Accordingly, the rod-shaped valve element 108 moves to the low-pressure chamber 122 side (to the left in FIG. 5), and the tapered surface of the first port 105a and the tapered head 108b of the rod-shaped valve element 108 are tapered. The area of the opening between the surface and the surface increases (the state of FIG. 5).
[0007]
As the pressure in the crank chamber 121 rises from this state, the bellows 106 and 107 are actuated by the pressure introduced from the crank chamber 121 into the casing 105 via the second communication passage 112 and the third port 105c. The state moves to the side opposite to the low pressure side 122 (to the right in FIG. 5) against the pressure introduced into the inner bellows 106. Therefore, the opening area between the tapered surface of the first port 105a and the tapered surface of the tapered head 108b of the rod-shaped valve element 108 is reduced.
[0008]
[Patent Document 1]
Japanese Utility Model Publication No. 63-32933 (page 4, column 8, line 33-page 5, column 10, line 10, FIG. 7)
[0009]
[Problems to be solved by the invention]
Japanese Utility Model Publication No. 63-32933 discloses a compressor having a displacement control valve and a variable orifice. Here, the capacity control is performed by controlling the amount of gas flowing from the discharge chamber to the crank chamber by controlling the communication between the discharge chamber and the crank chamber by the capacity control valve. As shown in FIG. 5, the variable orifice is used to adjust the amount of gas that escapes from the crank chamber to the suction chamber. When the crank chamber pressure increases, the differential pressure between the discharge chamber pressure and the crank chamber pressure increases. Since it becomes smaller, the orifice opening is configured to be smaller.
[0010]
By the way, in the configuration of the conventional example, when the compressor is started from a stopped state, there is a disadvantage that a smooth start-up operation cannot be performed. The reason is as follows.
[0011]
When the compressor is stopped, the crank chamber, the discharge chamber, and the suction chamber are at the same pressure. That is, since there is no difference in pressure between the crank chamber and the discharge chamber, the orifice opening is minimized. In this state, when the start switch is turned on, the rotation of the main shaft of the compressor is started, and at the same time, the electromagnetic solenoid is energized, and the displacement control valve is actuated by the electromagnetic solenoid to operate the valve between the crank chamber and the discharge chamber. Close. In order for the piston to operate at its maximum capacity together with the rotation of the main shaft of the compressor, the piston back pressure needs to be low, and therefore the gas pressure in the crank chamber needs to escape to the outside.
[0012]
However, in the above-mentioned prior art, since the orifice opening is in the minimum state, the amount of gas discharged from the crank chamber is small, so that the back pressure of the piston does not readily decrease. For this reason, at the time of startup, the compressor cannot operate at the maximum capacity, and the discharge capacity can be kept small. In this state, the discharge chamber pressure gradually increases, and the orifice opening gradually opens in accordance with this, eventually reaching the maximum opening degree, gradually reducing the crank chamber pressure sufficiently, and operating at the maximum discharge capacity. Will be.
[0013]
The present invention aims to solve this problem.
[0014]
According to the present invention, since the displacement control valve and the variable orifice opening are linked, not only the above object is achieved, but also in a steady displacement control operation, the suction pressure decreases and the displacement control valve opens. When this occurs, the variable orifice opening also becomes smaller in conjunction with the opening angle, so that the crank chamber pressure rises earlier. Therefore, the response speed of the inclination angle of the swash plate can be improved. That is, capacity control with a high response speed can be realized.
[0015]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems.
[0016]
1. A valve section is provided in a first passage communicating the discharge chamber and the crank chamber to variably control the discharge capacity of the compressor, and the opening degree of the valve section is controlled over the valve closed state and the maximum valve opening degree. A capacity control valve for adjusting the pressure of the crank chamber, and an opening of an orifice provided in a second passage communicating the crank chamber and the suction chamber, between a predetermined minimum orifice opening and a maximum orifice opening. A variable orifice mechanism having a variable orifice mechanism for controlling the amount of gas flowing from the crank chamber to the suction chamber by controlling the orifice to have the maximum orifice opening when the valve portion is in the valve closed state. A capacity control valve for interlocking the capacity control valve and the variable orifice mechanism such that the orifice has the minimum orifice opening when the valve portion is at the maximum valve opening. That the variable capacity compressor.
[0017]
2. 2. The variable displacement compressor according to claim 1, wherein a valve portion of the displacement control valve and a movable portion of the variable orifice mechanism are integrally formed.
[0018]
3. The valve section of the capacity control valve is disposed in a valve chamber provided in a valve casing, the valve chamber communicates with the crank chamber, and the movable section of the variable orifice mechanism has a hole in a partition provided in the valve casing. The pressure chamber, which is inserted and faces the valve chamber with the partition interposed therebetween, communicates with the suction chamber, and a gap between the movable section and the hole of the partition forms an orifice of the pressure relief passage. 3. The variable displacement compressor having the displacement control valve according to 1 or 2, wherein the flow rate of the refrigerant passing through the orifice changes according to the movement.
[0019]
4. A variable displacement compressor having a displacement control valve according to any one of claims 1, 2 and 3, wherein a rod is extended from the movable portion, and a solenoid portion is provided on the rod to apply an electromagnetic force in a direction to close a valve portion of the displacement control valve. Machine.
[0020]
5. The variable displacement compressor according to claim 4, further comprising a spring that opens a valve portion of the displacement control valve when the solenoid portion is demagnetized.
[0021]
6. The valve portion of the displacement control valve is in contact with a pressure-sensitive member that expands and contracts according to the pressure of the crank chamber or the pressure of the suction chamber via a rod, and the valve of the displacement control valve according to the expansion and contraction of the pressure-sensitive member. 6. A variable displacement compressor having a displacement control valve according to the above 1, 2, 3, 4 or 5 whose part is opened and closed.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
A variable displacement compressor having a displacement control valve according to an embodiment of the present invention will be described with reference to FIGS.
[0023]
FIG. 1 is a sectional view of the compressor. The variable displacement compressor 50 includes a cylinder block 51 having a plurality of cylinder bores 51a provided on a circumference around one axis in the front-rear direction, a front housing 52 provided at one end of the cylinder block 51, and a cylinder block. 51 includes a rear housing 53 provided via a valve plate device 54. A drive shaft 56 is provided so as to traverse the inside of a crank chamber 55 defined by the cylinder block 51 and the front housing 52, and a swash plate 57 is disposed around the center of the drive shaft 56.
[0024]
The swash plate 57 is connected to a rotor 58 fixed to the drive shaft 56 via a connecting portion (cam mechanism) 59.
[0025]
One end of the drive shaft 56 penetrates the inside of the boss 52a protruding outside the front housing 52 and extends to the outside. An electromagnetic clutch 70 is provided around the boss 52a via a bearing 60. I have.
[0026]
The electromagnetic clutch 70 includes a rotor 71 provided around the boss 52a, an electromagnet device 72 housed in the rotor 71, and a clutch plate 73 provided on one outer end surface of the rotor 71. One end of the drive shaft 56 is connected to the clutch plate 73 via a fixing member 74 such as a bolt.
[0027]
A seal member 52b is inserted between the drive shaft 56 and the boss 52a to shut off the inside and the outside of the variable displacement compressor 50. The other end of the drive shaft 56 is located inside the cylinder block 51 and is supported by a support member 78. Reference numerals 75, 76, and 77 are bearings.
[0028]
The piston 62 is disposed in the cylinder bore 51a, and the periphery of the outer peripheral portion of the swash plate 57 is accommodated in the recess 62a at one end inside the piston 62. The piston 62 and the slope 57 are interposed via the shoe 63. They are configured to work together.
[0029]
A suction chamber 65 and a discharge chamber 64 are defined in the rear housing 53, and the suction chamber 65 communicates with the cylinder bore 51a via a suction valve (not shown) provided in the valve plate device 54. And the cylinder bore 51a are connected via a discharge valve provided in the valve plate device 54. The capacity control valve 20 is provided in a recess in the rear wall of the rear housing 53.
[0030]
The configuration up to the above is the same as the conventional technology except for the capacity control valve 20.
[0031]
A displacement control valve according to two embodiments of the present invention used to control the compression displacement of the variable displacement compressor will be described.
[0032]
First, a capacity control valve according to the first embodiment will be described with reference to FIGS.
[0033]
The capacity control valve 20 is disposed in the valve casing 21, the lower chamber 21 a of the valve casing 21, and a bellows 22 that accommodates a coil spring 22 a with a vacuum inside, and adjusts the amount of expansion and contraction of the bellows 22. An adjusting member 23 fixed to a lower part of the valve casing, a first rod part 24a having a lower end abutting on an upper part of the bellows 22 and slidably supported by the valve casing 21, and integrally formed on an upper end of the first rod part 24a. A valve portion 24b for opening and closing communication passages 66 and 68 for communicating the crank chamber 55 and the discharge chamber 64 of the variable displacement compressor 50 in accordance with expansion and contraction of the bellows 22, and a step portion formed above the valve portion 24b ( A partition wall 25 through which the truncated cone portion 24c is inserted and fixed to the valve sequencing 21; a second rod portion 24d integrally formed on the upper end of the step portion 24c and protruding from the partition wall 25; The fixed core 26 fixed to the valve casing 21 through the portion 24d, the plunger 27 fixed to the upper part of the second rod portion 24d, and the fixed core 26 and the plunger 27 are disposed, and the plunger 27 is opened. A coil spring 28 that presses in the valve direction, a cylindrical member 29 made of a nonmagnetic material that houses the fixed iron core 26, the plunger 27, and the coil spring 28, and an electromagnetic coil 30 that is arranged on the outer peripheral portion of the cylindrical member 29. The electromagnetic coil 30 is housed therein and includes a housing 31 that fits in the valve casing 21 and a closing member 32 that closes one end of the electromagnetic coil 30 and forms a part of a magnetic path. The electromagnetic coil 30 and the closing member 32 are integrally formed of a resin member.
[0034]
The valve casing 21 has a valve chamber 21b in which the valve portion 24b is disposed. The pressure of the crank chamber 55 acts on the valve chamber 21b, and the pressure of the suction chamber 65 acts on the bellows 22. Since the pressure chamber 21c opposed to the valve chamber 21b with the partition wall 25 interposed therebetween communicates with the lower chamber 21a via the communication passage 21d, the pressure of the suction chamber 65 acts on the pressure chamber 21c. The step portion 24c and the hole 25a of the partition wall 25 into which the step portion 24c is inserted / extracted constitute a variable orifice mechanism, and the step portion 24c functions as a movable portion of the variable orifice mechanism. The step portion 24c does not contact the hole 25a of the partition wall 25, and the second rod portion 24d does not contact the hole 26a of the fixed iron core 26. The first rod portion 24a is slidably supported by the valve casing 21, and the plunger 27 is slidably supported by the tubular member 29. The discharge pressure acting on the valve portion 24b and the first rod portion 24a acts on substantially the same area in the vertical direction in FIG. 2 and is canceled out. As a result, the discharge pressure hardly increases in the axial direction of the valve portion 24b. Does not work. Therefore, the opening and closing of the valve portion 24b is controlled in accordance with the electromagnetic force of the electromagnetic coil 30 and the pressure of the suction chamber 65 acting on the bellows 22.
[0035]
The operation of the displacement control valve 20 will be described. When a predetermined current is applied to the electromagnetic coil 30, an electromagnetic force is generated on the opposing surface of the plunger 27 and the fixed iron core 26, so that a force (force in the valve closing direction) for attracting the plunger 27 to the fixed iron core 26 is applied. When the electromagnetic force exceeds a predetermined value, the valve portion 24b completely closes the communication passages 66 and 68, so that the communication between the crank chamber 55 and the discharge chamber 64 is cut off. As a result, the refrigerant in the discharge chamber 64 is not introduced into the crank chamber 55, so that a refrigerant flows from the crank chamber 55 to the suction chamber 65 via the variable orifice mechanism. At this time, since the large diameter portion of the step portion 24c comes off the hole 25a of the partition wall 25, the gap between the step portion 24c and the hole 25a of the partition wall 25 becomes large as shown in FIG. Accordingly, since the variable orifice mechanism has a diameter sufficient for flowing the blow-by gas generated when the piston 62 compresses the refrigerant into the suction chamber 65, the pressure of the crank chamber 55 decreases quickly, and the pressure of the suction chamber 65 decreases. It is equivalent to pressure. Therefore, the variable capacity compressor 50 is maintained at the maximum capacity, and the pressure in the suction chamber 65 gradually decreases.
[0036]
When the suction pressure decreases to a predetermined value, the bellows 22 extends, so that the valve portion 24b opens the communication passages 66 and 68. Therefore, since the refrigerant in the discharge chamber 64 is introduced into the crank chamber 55, the pressure difference between the crank chamber 55 and the suction chamber 65 increases, so that the discharge capacity decreases. As a result, when the pressure in the suction chamber 65 increases, the bellows 22 contracts, and the opening of the valve portion 24b decreases. Therefore, since the pressure in the crank chamber 55 decreases quickly, the pressure difference between the crank chamber 55 and the suction chamber 65 decreases, so that the discharge capacity increases. In this way, when the electromagnetic force generated by the electromagnetic coil 30 on the opposing surface between the fixed iron core 26 and the plunger 27 is constant, the valve portion 24b is connected to the communication passage 66 so that the pressure in the suction chamber 65 becomes a predetermined value. , 68 are adjusted, so that the discharge capacity is controlled.
[0037]
In a region where the valve portion 24b opens the communication passages 66 and 68 in a large degree, that is, in a region where the suction pressure is low, the large-diameter portion of the step portion 24c is inserted into the hole 25a of the partition wall 25. As shown in (2), the gap between the step portion 24c and the hole 25a of the partition 25 becomes small. Therefore, the amount of refrigerant escaping into the suction chamber 65 is reduced. For this reason, the amount of the discharge gas introduced into the crank chamber 55 is maintained at an appropriate amount without being excessive, in cooperation with the opening degree of the valve portion 24b.
[0038]
Also, by preventing the valve portion 24b from contacting the partition 25, the minimum orifice opening is guaranteed, and the gap between the step portion 24c and the hole 25a of the partition 25 provides a variable orifice opening. Furthermore, the coupling system (one member is formed) of the first rod portion 24a, the valve portion 24b, the step portion 24c, the second rod portion 24d, and the plunger 27 includes the valve casing 21 and the cylindrical member 29. Sliding is supported at only two places. Therefore, since the sliding resistance is small, the valve portion 24b moves smoothly. Accordingly, the opening and closing of the communication passages 66 and 68 by the valve portion 24b is high in accordance with the electromagnetic force generated on the opposing surface between the fixed iron core 26 and the plunger 27 by the electromagnetic coil 30 or the change in the pressure of the suction chamber 65. Done with precision.
[0039]
In the present invention, a diaphragm or the like may be used instead of the bellows.
[0040]
In the present invention, the communication passages 66 and 67 communicating the crank chamber 55 and the suction chamber 65 are pressure relief passages, and the communication passages 66 and 68 communicating the crank chamber 65 and the discharge chamber 64 are defined as discharge pressure supply passages. , Respectively.
[0041]
Next, a capacity control valve according to a second embodiment will be described with reference to FIG. Regarding the second embodiment, description of the same points as in the first embodiment will be omitted, and only different points will be described.
[0042]
The capacity control valve 40 of the second embodiment is different from the capacity control valve 20 of the first embodiment in that a communication passage 66 communicating with the crank chamber 55 and a communication passage 67 communicating with the suction chamber 65 are provided. On the contrary, it differs in that it has been changed.
[0043]
【The invention's effect】
As is clear from the above description, the present invention has the following effects.
[0044]
1. At the time of the maximum capacity, the opening of the pressure relief passage can be reliably set to the maximum opening, so that the refrigerant in the crank chamber can be quickly released to the suction chamber. Therefore, the startup characteristics at the time of starting the variable capacity compressor are improved.
[0045]
2. Since the displacement control valve has a built-in variable orifice mechanism, the structure of the variable displacement compressor is simplified.
[0046]
3. Since the sliding resistance accompanying the movement of the valve portion of the displacement control valve is reduced, the displacement of the variable displacement compressor is smoothly controlled.
[Brief description of the drawings]
FIG. 1 is a sectional view of a variable displacement compressor having a displacement control valve according to a first embodiment of the present invention.
FIG. 2 is a sectional view of the displacement control valve.
3A and 3B are cross-sectional views of a variable orifice mechanism in the displacement control valve, wherein FIG. 3A shows a state when the valve is fully closed, and FIG. 3B shows a state when the valve is fully opened.
FIG. 4 is a sectional view of a displacement control valve according to a second embodiment of the present invention.
FIG. 5 is a sectional view of a displacement control valve used in a conventional variable displacement compressor.
[Explanation of symbols]
Reference Signs List 20 Capacity control valve 21 Valve casing 21a Lower chamber 21b Valve chamber 21c Pressure chamber 21d Communication passage 22 Bellows 22a Coil spring 23 Adjusting member 24a First rod portion 24b Valve portion 24c Step portion (frustoconical portion)
24d Second rod portion 25 Partition wall 25a Hole 26 Fixed iron core 26a Hole 27 Plunger 28 Coil spring 29 Cylindrical member 30 Electromagnetic coil 31 Housing 32 Closing member 40 Capacity control valve 50 Variable capacity compressor 55 Crank chamber 62 Piston 64 Discharge chamber 65 Suction Chamber 66 Communication passage 67 Communication passage 68 Communication passage

Claims (6)

A valve section is provided in a first passage communicating the discharge chamber and the crank chamber to variably control the discharge capacity of the compressor, and the opening degree of the valve section is controlled over the valve closed state and the maximum valve opening degree. A capacity control valve for adjusting the pressure of the crank chamber, and an opening of an orifice provided in a second passage communicating the crank chamber and the suction chamber, between a predetermined minimum orifice opening and a maximum orifice opening. A variable orifice mechanism that controls the amount of gas flowing from the crank chamber to the suction chamber by controlling the variable displacement compressor.
The orifice is at the maximum orifice opening when the valve is in the valve closed state, and the orifice is at the minimum orifice opening when the valve is at the maximum valve opening. A variable displacement compressor having a displacement control valve, which is linked with a variable orifice mechanism. The variable displacement compressor having a displacement control valve according to claim 1, wherein a valve portion of the displacement control valve and a movable portion of the variable orifice mechanism are integrally formed. The valve section of the capacity control valve is disposed in a valve chamber provided in a valve casing, the valve chamber communicates with the crank chamber, and the movable section of the variable orifice mechanism has a hole in a partition provided in the valve casing. The pressure chamber facing the valve chamber across the partition wall communicates with the suction chamber, a gap between the movable section and the hole of the partition wall forms an orifice of the pressure relief passage, 3. The variable displacement compressor according to claim 1, wherein a flow rate of the refrigerant passing through the orifice changes according to the movement. The capacity control according to claim 1, 2, or 3, wherein a rod is extended from the movable part, and a solenoid is provided on the rod to apply an electromagnetic force in a direction to close a valve part of the capacity control valve. Variable displacement compressor with valve. The variable displacement compressor according to claim 4, further comprising a spring that opens a valve portion of the displacement control valve when the solenoid portion is demagnetized. The valve portion of the displacement control valve is in contact with a pressure-sensitive member that expands and contracts according to the pressure of the crank chamber or the pressure of the suction chamber via a rod, and the valve of the displacement control valve according to expansion and contraction of the pressure-sensitive member. 6. The variable displacement compressor having a displacement control valve according to claim 1, wherein the portion is opened and closed.

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