JP2005282414A - Control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a problem caused by micro vibrations of a plunger in pulse width modulation (PWM). <P>SOLUTION: A control valve in which movement of its valve element is controlled, comprises: an electromagnetic coil energized and controlled by the pulse width modulation; the plunger moved by an attraction force from the electromagnetic coil; an adjusting spring resisting the attraction force; and a diaphragm of the plunger converting into a force against the adjusting spring. For applying friction to a member which is displaced together with the valve element, grease is sealed in a circumference of the plunger. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control valve mainly used in a variable capacity compressor for refrigerant compression of an automobile air conditioner, and more particularly to a control valve of a pulse width modulation control system.

  A variable capacity compressor employed in an air conditioner for an automobile has a swash plate provided with a variable inclination angle in a crank chamber that oscillates by the rotation of a rotating shaft, and a plurality of pistons rotate by the oscillating motion. The refrigerant is sucked, compressed, and discharged by reciprocating in a direction parallel to the direction. At this time, by changing the pressure in the crank chamber by the control valve, the inclination angle of the swash plate is changed, and the stroke of the piston is changed to make the refrigerant discharge capacity variable.

Such a control valve has two first and second valve bodies that operate in conjunction with a refrigerant passage that connects the discharge chamber and the crank chamber and a refrigerant passage that connects the crank chamber and the suction chamber, respectively. A control valve has been proposed in which the flow rate of refrigerant entering the crank chamber and the flow rate of refrigerant extracted from the crank chamber are controlled in comparison with the amount of movement of the transmission rod (for example, Patent Document 1).
JP-A-5-99136

  In the control valve, the magnetic attractive force generated in the electromagnetic coil is often controlled by pulse width modulation (PWM). In the example in which the valve opening is controlled by this pulse width modulation, Since the power return efficiency is better when the width modulation frequency is higher, the PWM frequency is set to about 400 Hz.

  At a PWM frequency of 400 Hz, the vibration of the plunger (about 0.03 mm) is generated, so that the first valve body of the ball valve resonates and becomes larger than the target opening, especially the control characteristics, There has been a problem with the introduction control for introducing the discharge pressure into the crank chamber.

  Accordingly, an object of the present invention is to stabilize control of a control valve by preventing inconvenience caused by minute vibration of a plunger by PWM frequency control.

  In order to achieve the above object, in the control valve according to the present invention, the magnetic attractive force generated from the electromagnetic coil that is energized and controlled by pulse width modulation to the plunger, and the spring force of the adjusting spring that counteracts this attractive force In a control valve in which the position of the valve body is determined from a balanced relationship with a force that opposes the spring force of the adjustment spring by a diaphragm provided on the anti-electromagnetic coil side of the plunger, a friction is given to a member that is displaced together with the valve body Means are provided (claim 1). Thereby, the slight vibration of the valve body which occurs in the control of the PWM frequency is suppressed, and the opening degree is held at a predetermined amount. The valve body used here has two valve mechanisms, one of which is a spool-type valve body and the other is a ball-type valve body (Claim 2).

  As a means for giving the friction to the member that is displaced together with the valve body, first, grease is sealed around the plunger surrounded by the diaphragm. Second, an inclined spring seat is attached to a push rod to which an adjustment spring that opposes the movement of the plunger is mounted. Third, an O-ring is provided on a push rod to which an adjustment spring that opposes the movement of the plunger is mounted (Claim 5). Fourth, the pressure of the liquid is applied to the side surface of the rod interlocked with the movement of the valve body (Claim 6).

  As a result, in the first example, the plunger is given a friction due to the viscosity of the grease, and in the second example, an inclined spring seat has an offset effect on the adjustment spring mounted on the push rod. In addition, in the third example, the push rod is provided with an o-ring in the third example, so that the friction is given, and in the fourth example, on the side surface of the rod interlocked with the movement of the valve body. Crisis is given because pressure is applied.

  As described above, according to the present invention, the slight vibration generated in the valve body of the control valve using pulse width modulation (PWM) is suppressed, the opening degree of the valve body is maintained at a predetermined amount, and the flow rate control is stabilized. It will be. That is, the friction is given by the viscosity of the oil arranged around the plunger, the tilting spring seat of the adjusting spring gives the adjustment by the adjusting spring contacting the push rod, and the O-ring contacts the push rod. This is because the friction is applied, and the friction is applied by applying pressure to the side surface of the rod interlocked with the movement of the valve body.

  Hereinafter, embodiments of the present invention and drawings will be described.

  1 to 3, a control valve 1 according to a first embodiment of the present invention is shown. This control valve 1 is used for pressure control in the crank chamber of the variable capacity compressor, and is roughly composed of a mechanical output portion 2 and a valve portion 21. The mechanical output portion 2 extends from the body 3a and accommodates an electromagnetic coil 5 wound around a bobbin 4 inside a cylindrical case 3b.

  A guide pipe 6 made of a non-magnetic material is provided in the through-hole at the center of the bobbin 4, and a suction rod 7 made of a magnetic material is fitted in the guide pipe 6 in the upper part of the drawing. A plunger working chamber 10 in which the plunger 9 that moves up and down is formed.

  The suction rod 7 is formed with a vertical hole 11 in the axial direction, the lower hole 11 has a small-diameter portion and the upper portion has a large-diameter portion, and is closed with a lid 12 provided on the large-diameter portion side. A push rod 14 is slidably disposed in the vertical hole 11, and a lower end thereof is brought into contact with a plunger 9 described below, and an upper end thereof reaches a large diameter portion of the vertical hole 11 and contacts the adjustment spring 16. It is touched. That is, the adjustment spring 16 is interposed between a spring seat 15 attached to the push rod 14 and an adjustment screw 17 screwed into the lid 12. The setting force of the adjustment spring 16 can be changed by rotating the adjustment screw 17.

  The plunger 9 is made of a magnetic material and is disposed in a plunger working chamber 10 defined by a diaphragm 19 provided at the lower end thereof. The upper end of the plunger 9 is brought into contact with the push rod 14 and the lower end thereof is connected through the diaphragm 19 to the following. The valve body 25 is abutted. That is, the position of the plunger 9 is determined by the equilibrium relationship between the adjustment spring 16 of the push rod 14 and the suction force from the suction rod 9 described above, and the spring force of the adjustment spring 16 when the electromagnetic coil 5 is not energized. Thus, the plunger 9 is displaced most downward against the return spring 28 that supports the valve body 25. The plunger working chamber 10 is filled with silicon grease, which is a highly viscous liquid.

  The valve portion 21 is attached to the body 3a of the mechanical output portion 2 with a diaphragm 19 interposed therebetween. A vertical hole 23 is formed in the valve housing 22 in the vertical direction, and the upper side is a large diameter portion. 23a, and the suction pressure of the variable capacity compressor is guided to the large diameter portion 23a through a communication hole 24 formed in the lateral direction.

  Further, a spool type valve element 25 is disposed in the vertical hole 23, and the spool type valve element 25 is slidable with respect to the valve seat 26 and the vertical hole 23, and extends downward. 25b is connected. The spool-type valve body 25 is urged toward the plunger 9 by a return spring 28, and a head portion 25 a abuts against a lower portion of the plunger 9. Due to the displacement of the spool type valve element 25, the pressure in the crank chamber is controlled to be released into the large diameter portion 23a through the communication hole 30 communicating with the crank chamber from the relationship with the valve seat 26. When the electromagnetic coil 5 is not energized, the spool type valve element 25 is fully closed.

  A ball-type valve body 31 is connected to the vertical hole 23 and is provided between a communication hole 33 communicating with the crank chamber and a communication hole 34 communicating with the discharge chamber, and is opened by being pressed by the rod 27. Therefore, when the electromagnetic coil 5 is not energized, it is pressed by the rod 27 pressed by the spring force of the adjustment spring 16 and is separated from the valve seat 36 to be fully opened. ing. Therefore, the discharge pressure can flow into the crank chamber.

  In the above-described configuration, the operation of the control valve 1 will be described. The electromagnetic coil 5 is energized and controlled by pulse width modulation (PWM) of 400 HZ, and the plunger 9 is moved in proportion to the magnetic attractive force generated in the electromagnetic coil 5. A predetermined amount is displaced against the adjustment spring 16.

  When the displacement amount of the plunger 9, that is, the stroke amount of the spool type valve element 25 moves from 0 to the maximum, the rod 25b moves backward, and the ball valve 31 in the fully opened state is gradually throttled, and is completely closed at a substantially intermediate position. (Pd-Pc line in FIG. 3). That is, the supply of the discharge pressure to the crank chamber is changed. After that, when the intermediate position is passed, the spool-type valve body 25 that has been fully closed begins to open and gradually expands, and is controlled as indicated by the Pc-Ps line in FIG. 3, and the outflow of pressure in the crank chamber is changed. .

  Although a slight vibration (about 0.03 mm) of 400 HZ is generated in the plunger 9, friction is given around the plunger 9 by the sealed silicon grease, and the fine vibration is absorbed. Therefore, a slight vibration is not transmitted to the ball-type valve body 31 which is controlled to be opened and closed by the rod 27 connected to the spool-type valve body 25, and the inconvenience of exceeding the target opening as in the prior art is prevented. Can be set to the opening.

  FIG. 4 shows a second embodiment of the present invention. In this example, a fine vibration is not transmitted to the ball-shaped valve body 31 by giving a friction to the push rod 14. In other words, the spring seat 15 of the adjustment spring 16 is given a predetermined inclination (θ) to give an offset effect to the adjustment spring 16, and the adjustment spring 16 is brought into contact with the push rod 14. Also by this, the fine vibration generated in the plunger 9 can be absorbed.

  FIG. 5 shows a third embodiment of the present invention. In this example, a fine vibration is not transmitted to the ball-shaped valve body 31 by applying a friction to the push rod 14 as in the above example. In other words, the O-rings 38a and 38b are provided at one or two places of the push rod 14. Also by this, the fine vibration generated in the plunger 9 can be absorbed.

  FIG. 6 shows a fourth embodiment of the present invention. In this example, a fine vibration is not transmitted to the ball-type valve body 31 by applying a friction to the rod 25b of the spool-type valve body 25. That is, the pressure supply hole 40 is formed in the side surface of the vertical hole 23 so as to hit the rod 25b, and for example, discharge pressure is applied to the side surface of the rod 25b through the pressure supply hole 40. Also by this, the fine vibration generated in the plunger 9 can be absorbed. In the second to fourth embodiments, the same parts as those in the first embodiment are denoted by the same reference numerals and omitted from the description.

It is sectional drawing which shows 1st Example of this invention. It is an enlarged view of the principal part same as the above. It is a characteristic diagram which shows the movement of the valve body of the said 1st Example, and the relationship of an opening degree. It is a principal part enlarged view which shows the 2nd Example of this invention. It is a principal part enlarged view which shows the 3rd Example of this invention. It is a principal part enlarged view which shows the 4th Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control valve 2 Mechanical output part 5 Electromagnetic coil 7 Suction rod 9 Plunger 10 Plunger working chamber 11 Vertical hole 14 Push rod 15 Spring seat 16 Adjustment spring 19 Diaphragm 21 Valve part 23 Vertical hole 24 Communication hole 25 Spool type valve body 25b Rod 30 Communication hole 31 Ball type valve element 38a, 38b O-ring 40 Pressure supply hole

Claims (6)

Magnetic attraction force generated from the electromagnetic coil that is energized and controlled by pulse width modulation to the plunger;
The spring force of the adjusting spring against this suction force;
In the control valve in which the position of the valve body is determined from the equilibrium relationship with the force against the spring force of the adjustment spring by the diaphragm provided on the anti-electromagnetic coil side of the plunger,
A control valve comprising means for giving a friction to a member that is displaced together with the valve body.   2. The control valve according to claim 1, wherein the valve body has two valve functions, one is a spool-type valve body and the other is a ball-type valve body.   2. The control valve according to claim 1, wherein grease is sealed around the plunger surrounded by the diaphragm so as to give a friction to the movement of the diaphragm.   2. A tilted spring seat is attached to a push rod to which an adjustment spring that opposes the movement of the plunger is mounted, and an offset effect is given to the adjustment spring to give a friction to the push rod. The control valve described.   The control valve according to claim 1, wherein an o-ring is provided on a push rod to which an adjustment spring that opposes the movement of the plunger is provided to give a friction to the push rod.   3. The control valve according to claim 1, wherein a liquid pressure is applied to a side surface of the rod interlocked with the movement of the valve body to give a friction to the valve body.

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