Patent Description:
A variable displacement compressor used for an air conditioning system of an automobile, etc. includes a rotating shaft to be driven and rotated by an engine, a swash plate coupled to the rotating shaft in such a manner that a tilt angle is variable, compressing pistons coupled to the swash plate, etc., and by changing the tilt angle of the swash plate, changes a stroke amount of the pistons to control a discharge amount of a fluid. This tilt angle of the swash plate can be continuously changed by appropriately controlling pressure in a control chamber while utilizing suction pressure Ps of a suction chamber that suctions the fluid, discharge pressure Pd of a discharge chamber that discharges the fluid pressurized by the pistons, and control pressure Pc of the control chamber that houses the swash plate, with using a capacity control valve to be driven to open and close by electromagnetic force.

At the time of continuously driving the variable displacement compressor, the capacity control valve performs normal control in which energization is controlled by a control computer, a valve element is moved in the axial direction by electromagnetic force generated in a solenoid, and a DC valve provided between a discharge port through which a discharge fluid of the discharge pressure Pd passes and a control port through which a control fluid of the control pressure Pc passes is opened and closed to adjust the control pressure Pc of the control chamber of the variable displacement compressor.

At the time of normal control of the capacity control valve, the pressure of the control chamber in the variable displacement compressor is appropriately controlled, and by continuously changing the tilt angle of the swash plate with respect to the rotating shaft, the stroke amount of the pistons is changed to control the discharge amount of the fluid to the discharge chamber. Thus, the air conditioning system is adjusted to have a target cooling ability.

In the capacity control valve of Patent Citation <NUM>, by opening and closing the DC valve to control the fluid of the discharge pressure Pd supplied to the control chamber of the variable displacement compressor and bringing a pressure difference between the discharge pressure Pd of the discharge chamber and the control pressure Pc of the control chamber respectively applied in the stroke direction of the pistons close to a target value, the discharge amount of the fluid discharged from the discharge chamber is changed. A valve opening degree of the DC valve is changed in accordance with the electromagnetic force by an electric current applied to the solenoid, and in response to this, the target value of the pressure difference is changed, so that the discharge amount of the fluid discharged from the discharge chamber is changed.

In Patent Citation <NUM>, by Pd-Pc control that makes adjustment in such a manner that the fluid of the discharge pressure Pd is supplied to the control chamber to increase the control pressure Pc, it is possible to promptly perform pressure adjustment. However, in order to perform more precise pressure adjustment, a pressure sensitive body having a bellows is provided in a pressure sensitive chamber of the capacity control valve, and by extending and contracting the pressure sensitive body in the moving direction of the valve element in accordance with the suction pressure Ps, bias force is applied in the valve opening direction of the valve element, and the valve opening degree of the DC valve is adjusted. In such a way, by adjusting the valve opening degree of the DC valve by the pressure sensitive body that senses the suction pressure Ps with respect to fixed electromagnetic force in accordance with the electric current applied to the solenoid, the control pressure Pc is finely adjusted additionally taking the suction pressure Ps in consideration, and precision for controlling the discharge amount of the fluid discharged from the discharge chamber is enhanced.

In Patent Citation <NUM> a displacement control valve for a variable displacement compressor is described which includes a first valve hole forming a part of a supply passage and a second valve hole forming a part of a discharge passage. Displacement of a reciprocating body is transmitted to each of first and second valve bodies so that each valve body opens or closes the corresponding valve hole. When the reciprocating body is within a predetermined displacement range, a double closing state occurs, in which the first valve body closes the first valve hole and the second valve hole closes the second valve hole. When the reciprocating body is out of the displacement range, a single closing state occurs. Therefore, the control valve prevents the first valve hole from opening concurrently with the second valve hole.

In the capacity control valve of Patent Citation <NUM>, in addition to the Pd-Pc control, by using the pressure sensitive body that senses the suction pressure Ps and correcting actions of the valve element, the valve opening degree of the DC valve is adjusted and the precision for controlling the discharge amount of the fluid discharged from the discharge chamber is enhanced. However, the suction pressure Ps is low pressure and exerts a little influence on the actions of the valve element. Thus, there is a problem that it takes time before control pressure of the air conditioning system reaches a target value by adjustment of the valve opening degree.

The present invention is achieved focusing on such a problem, and an object thereof is to provide a capacity control valve in which a valve opening degree can be favorably adjusted.

In order to solve the foregoing problem, a capacity control valve according to claim <NUM> to <NUM> is provided. The capacity control valve including a valve housing provided with a suction port through which a
suction fluid of suction pressure passes, and a control port through which a control fluid of control pressure passes, a valve element configured to be driven by a solenoid, a spring that biases the valve element in a direction opposite to a driving direction by the solenoid, and a CS valve formed by a CS valve seat and the valve element and configured for opening and closing a communication between the control port and the suction port by a movement of the valve element. The control pressure is controlled by opening and closing the CS valve, and the capacity control valve further includes a pressure receiving portion to which force in accordance with discharge pressure is applied in an axial direction of the valve element. According to the aforesaid feature of the present invention, it is possible to correct actions of the valve element by the discharge pressure which is high pressure. Therefore, a valve opening degree of the CS valve is more easily adjusted and it is possible to let the control pressure of an air conditioning system reach a target value in a shorter time.

It may be preferable that the pressure receiving portion is provided in the valve element. According to this preferable configuration, it is possible to apply force in accordance with the discharge pressure to the valve element operated by electromagnetic force of the solenoid. Thus, responsiveness to correction of the actions of the valve element is high.

It may be preferable that the pressure receiving portion is provided in a sliding rod which is a separate body separated from and facing the valve element. According to this preferable configuration, by combining the actions of the valve element driven by the solenoid and actions of the sliding rod by application of the force in accordance with the discharge pressure in the axial direction, it is possible to set a region where the actions of the valve element are corrected and a region where the actions are not corrected. Thus, control characteristics by correction are more easily appropriately changed.

It may be preferable that the sliding rod is connectably separated from the valve element. According to this preferable configuration, a region before the sliding rod is brought into contact with the valve element can be set as a buffering region where the force in accordance with the discharge pressure is not applied to the actions of the valve element.

It may be preferable that a biasing member is provided between the sliding rod and the valve element. According to this preferable configuration, the force in accordance with the discharge pressure, the force being applied to the sliding rod is applied to the valve element via the biasing member. Thus, the region before the sliding rod is brought into contact with the valve element can be set as a buffering region where the force in accordance with the discharge pressure is less easily applied to the actions of the valve element.

It may be preferable that a biasing member is provided between the sliding rod and the valve housing. According to this preferable configuration, the region before the sliding rod is brought into contact with the valve element can be set as the buffering region where the force in accordance with the discharge pressure is not applied to the actions of the valve element. By bringing the sliding rod into contact with the valve element, it is possible to apply the force in accordance with the discharge pressure, the force being applied to the sliding rod to the valve element in a state of suppressing by bias force of the biasing member.

It may be preferable that a seal portion that seals a part between the valve element and a guide hole provided in the valve housing is provided on the axially opposite side of the solenoid. According to this preferable configuration, the part is sealed in such a manner that a discharge fluid of the discharge pressure applied to the pressure receiving portion of the valve element does not intrude the valve housing. Thus, the discharge pressure less easily directly influences the control pressure and the suction pressure.

It may be preferable that a seal portion that seals a part between the sliding rod and a guide hole provided in the valve housing is provided on an axially opposite side of the solenoid. According to this preferable configuration, the part is sealed in such a manner that the discharge fluid of the discharge pressure applied to the pressure receiving portion of the sliding rod does not intrude the valve housing. Thus, the discharge pressure less easily directly influences the control pressure and the suction pressure.

It may be preferable that the valve element is biased in a valve opening direction of the CS valve by the spring. According to this preferable configuration, by moving the valve element in the valve opening direction at the time of non-energization, the control pressure and the suction pressure more easily match with each other, and it is possible to instantaneously restore to normal control from the maximum energized state.

Modes for carrying out a capacity control valve according to the present invention will be described below based on embodiments. The following first, second and third embodiments are not according to the invention and are present for illustration purposes only.

A capacity control valve according to a first embodiment will be described with reference to <FIG>. Hereinafter, description will be given with the left and right sides seen from the front side of <FIG> being the left and right sides of the capacity control valve.

A capacity control valve V1 according to the first embodiment of the present invention is assembled into a variable displacement compressor (not shown) used for an air conditioning system of an automobile, etc. By variably controlling pressure of a working fluid (hereinafter, simply referred to as the "fluid") serving as a coolant, a discharge amount of the variable displacement compressor is controlled and the air conditioning system is adjusted to have a target cooling ability.

First, the variable displacement compressor will be described. The variable displacement compressor has a casing including a discharge chamber, a suction chamber, a control chamber, and plural cylinders. A communication passage providing direct communication between the discharge chamber and the control chamber is provided in the variable displacement compressor. A fixed orifice <NUM> for adjusting to balance pressure between the discharge chamber and the control chamber is provided in this communication passage (see <FIG> and <FIG>).

The variable displacement compressor also includes a rotating shaft to be driven and rotated by an engine (not shown) installed outside the casing, a swash plate coupled to the rotating shaft in an eccentric state by a hinge mechanism in the control chamber, and plural pistons coupled to the swash plate and fitted reciprocatably in the respective cylinders. With using the capacity control valve V1 to be driven to open and close by electromagnetic force, a tilt angle of the swash plate is continuously changed by appropriately controlling pressure in the control chamber while utilizing suction pressure Ps of the suction chamber that suctions the fluid, discharge pressure Pd of the discharge chamber that discharges the fluid pressurized by the pistons, and control pressure Pc of the control chamber that houses the swash plate. Thereby, a stroke amount of the pistons is changed to control a discharge amount of the fluid.

As shown in <FIG> and <FIG>, the capacity control valve V1 assembled into the variable displacement compressor adjusts an electric current energized in a coil <NUM> forming a solenoid <NUM> and performs open/close control of a CS valve <NUM> in the capacity control valve V1, so that by controlling the fluid flowing out to the suction chamber from the control chamber, the control pressure Pc in the control chamber is variably controlled. A discharge fluid of the discharge pressure Pd of the discharge chamber is always supplied to the control chamber via the fixed orifice <NUM>, and the control pressure Pc in the control chamber can be increased by closing the CS valve <NUM> in the capacity control valve V1.

In the first embodiment, the CS valve <NUM> is formed by a CS valve element <NUM> serving as a valve element and a CS valve seat 10a formed on an inner peripheral surface of a valve housing <NUM>. By bringing and separating a step portion 51a formed in an axially left end portion of a large diameter portion 51b of the CS valve element <NUM> into contact with and from the CS valve seat 10a, the CS valve <NUM> is opened and closed.

Next, a structure of the capacity control valve V1 will be described. As shown in <FIG> and <FIG>, the capacity control valve V1 is mainly formed by the valve housing <NUM> made of a metal material or a resin material, the CS valve element <NUM> whose axially left end portion is arranged in the valve housing <NUM>, and the solenoid <NUM> connected to the valve housing <NUM>, the solenoid that applies drive force to the CS valve element <NUM>.

As shown in <FIG> and <FIG>, the solenoid <NUM> is mainly formed by a casing <NUM> having an opening portion 81a which is open on the axially left side, a substantially cylindrical center post <NUM> inserted into the opening portion 81a of the casing <NUM> from the axially left side and fixed on the radially inner side of the casing <NUM>, the CS valve element <NUM> inserted into the center post <NUM> reciprocatably in the axial direction, the center post whose axially left end portion is arranged in the valve housing <NUM>, a movable iron core <NUM> to which an axially right end portion of the large diameter portion 51b of the CS valve element <NUM> is inserted and fixed, a coil spring <NUM> provided between the center post <NUM> and the movable iron core <NUM>, the coil spring serving as a spring that biases the movable iron core <NUM> to the axially right side which is the valve opening direction of the CS valve <NUM>, and the excitation coil <NUM> wound on the outside of the center post <NUM> via a bobbin.

As shown in <FIG> and <FIG>, the CS valve element <NUM> is a stepped and pillar-shaped body formed by integrating the large diameter portion 51b in which the step portion 51a is formed in an axially left end and a small diameter portion 51c provided continuously to the axially left side of the large diameter portion 51b, the small diameter portion having a smaller diameter than the large diameter portion 51b, and also serves as a rod arranged to pass through the coil <NUM> of the solenoid <NUM>. The small diameter portion 51c has a constriction portion 51e having a smaller diameter than an axially left end of the small diameter portion 51c in a part which is continuous to the step portion 51a of the large diameter portion 51b. Thus, a flow passage having a constant section is ensured at the time of opening the CS valve <NUM>.

As shown in <FIG> and <FIG>, in the valve housing <NUM>, a Ps port <NUM> serving as a suction port which communicates with the suction chamber of the variable displacement compressor, and a Pc port <NUM> serving as a control port which communicates with the control chamber of the variable displacement compressor are formed.

Inside the valve housing <NUM>, a first valve chamber <NUM> communicating with the Ps port <NUM>, the first valve chamber in which the axially left end portion of the large diameter portion 51b of the CS valve element <NUM> is arranged reciprocatably in the axial direction is formed on the axially right side, that is, on the solenoid <NUM> side, and a second valve chamber <NUM> communicating with the Pc port <NUM>, the second valve chamber in which the small diameter portion 51c of the CS valve element <NUM> is arranged reciprocatably in the axial direction is formed on the axially left side.

On the inner peripheral surface of the valve housing <NUM>, a valve hole 10b providing communication between the first valve chamber <NUM> and the second valve chamber <NUM>, the valve hole into which the small diameter portion 51c of the CS valve element <NUM> is inserted is formed. On the inner peripheral surface of the valve housing <NUM>, the CS valve seat 10a is formed at an opening end edge of the valve hole 10b on the first valve chamber <NUM> side.

On the inner peripheral surface of the valve housing <NUM>, a guide hole 10c with which an outer peripheral surface of the small diameter portion 51c of the CS valve element <NUM> is slidable in a substantially sealed state is formed on the axially left side of the second valve chamber <NUM>, that is, on the axially opposite side of the solenoid <NUM>. Between an inner peripheral surface of the guide hole 10c and the outer peripheral surface of the small diameter portion 51c of the CS valve element <NUM>, a minute gap is formed by slightly separating in the radial direction. The CS valve element <NUM> is smoothly movable with respect to the valve housing <NUM> in the axial direction.

The small diameter portion 51c of the CS valve element <NUM> projects to the axially left side from the guide hole 10c of the valve housing <NUM>. A pressure receiving surface 51d serving as a pressure receiving portion that receives the discharge pressure Pd of the discharge chamber of the variable displacement compressor is formed in an axially left end of the CS valve element <NUM>, that is, the axially left end of the small diameter portion 51c.

Next, actions of the capacity control valve V1, mainly actions of opening and closing the CS valve <NUM> will be described.

First, a non-energized state of the capacity control valve V1 will be described. As shown in <FIG>, in the capacity control valve V1, in a non-energized state, by pressing the movable iron core <NUM> to the axially right side by bias force of the coil spring <NUM>, the CS valve element <NUM> is moved to the axially right side together, the step portion 51a of the CS valve element <NUM> is separated from the CS valve seat 10a, and the CS valve <NUM> is opened.

At this time, to the CS valve element <NUM>, the bias force Fsp of the coil spring <NUM>, force FPd by the discharge pressure Pd of the discharge fluid to the pressure receiving surface 51d having a pressure receiving area B which is equal to a sectional area of the small diameter portion 51c of the CS valve element <NUM>, and force FPc by the control pressure Pc of the control fluid to the CS valve element <NUM> are applied to the axially right side, and force FPs by the suction pressure Ps of the suction fluid to the CS valve element <NUM> is applied to the axially left side. That is, given that the right side is the positive side, force Frod = Fsp + FPd + FPc - FPs is applied to the CS valve element <NUM>. By making a valve opening portion area A where the step portion 51a of the CS valve element <NUM> and the CS valve seat 10a are brought into contact with and separated from each other and the pressure receiving area B of the CS valve element <NUM> substantially the same as each other, it is possible to cancel an influence of the control pressure Pc applied to the CS valve element <NUM>.

Next, an energized state of the capacity control valve V1 will be described. As shown in <FIG>, in the capacity control valve V1, in an energized state, that is, at the time of normal control, at the time of so-called duty control, when electromagnetic force Fsol generated by applying the electric current to the solenoid <NUM> exceeds the force Frod (i.e., Fsol > Frod), by pulling the movable iron core <NUM> to the axially left side, that is, toward the center post <NUM>, and moving the CS valve element <NUM> fixed to the movable iron core <NUM> to the axially left side together, the step portion 51a of the CS valve element <NUM> is seated on the CS valve seat 10a, and the CS valve <NUM> is closed.

At this time, to the CS valve element <NUM>, the electromagnetic force Fsol is applied on the axially left side, and the force Frod is applied on the axially right side. That is, given that the right side is the positive side, force Frod - Fsol, in detail, force Fsp + FPd + FPc - FPs - Fsol is applied to the CS valve element <NUM>.

The discharge pressure Pd applied to the pressure receiving surface 51d of the CS valve element <NUM> is occasionally changed in accordance with the discharge amount of the variable displacement compressor required from the air conditioning system. Therefore, the force FPd applied to the CS valve element <NUM> to the axially right side is changed in accordance with the discharge pressure Pd. In a case where the electric current energized in the solenoid <NUM> is constant, as shown by a solid graph line in <FIG>, an opening area of the CS valve <NUM> is increased in proportion to the discharge pressure Pd. As shown by a dotted graph line in <FIG>, when the discharge pressure Pd is not applied to the pressure receiving surface 51d of the CS valve element <NUM>, and in a case where an electric current I energized in the solenoid <NUM> is constant, the opening area of the CS valve <NUM> is not changed (the same applies to dotted graph lines in <FIG>, <FIG>, and <FIG> to be described later).

According to this, in the capacity control valve V1, Pc-Ps control that opens and closes the CS valve <NUM> to supply the control fluid of the control pressure Pc supplied from the Pc port <NUM> to the suction chamber via the Ps port <NUM> and lower the control pressure Pc of the control chamber is performed, and the discharge pressure Pd which is higher pressure than the control pressure Pc and the suction pressure Ps can be applied to the pressure receiving surface 51d of the CS valve element <NUM> to the axially right side, that is, in the valve opening direction of the CS valve <NUM>, and used for correction of actions of the CS valve element <NUM>. Therefore, a valve opening degree of the CS valve <NUM> is more easily adjusted and it is possible to let the control pressure Pc of the air conditioning system reach a target value in a short time.

By forming the pressure receiving surface 51d to which the discharge pressure Pd is applied in the CS valve element <NUM>, it is possible to apply the force FPd in accordance with the discharge pressure Pd to the CS valve element <NUM> having the step portion 51a where the CS valve <NUM> is opened and closed. Thus, responsiveness to correction of the actions of the CS valve element <NUM> is high. In addition, there is no need for adjusting the actions of the CS valve element <NUM> by using a pressure sensitive body unlike conventional examples, and by using the discharge pressure Pd which is high pressure for correction of the actions of the CS valve element <NUM>, an axial end surface of the CS valve element <NUM> formed by the pillar-shaped body is utilized as the pressure receiving surface 51d, so that the pressure receiving area can be decreased. Thus, it is possible to provide the capacity control valve V1 in which the number of parts is small, and size is reduced.

By using the discharge pressure Pd for correction of the actions of the CS valve element <NUM>, it is possible to adjust the valve opening degree of the CS valve <NUM> following a change in the discharge pressure Pd in accordance with a supply amount of the discharge fluid supplied to the control chamber via the fixed orifice <NUM> which is provided in the variable displacement compressor or a leakage amount of the discharge fluid by a blow-by gas leaked to the control chamber from a gap which is formed between the cylinders and the pistons of the variable displacement compressor. Thus, it is possible to let the control pressure Pc of the air conditioning system reach the target value in a shorter time.

The capacity control valve V1 is formed as a normal open type in which the CS valve element <NUM> is biased in the valve opening direction of the CS valve <NUM> by the coil spring <NUM>. Thus, it is possible to reliably move the CS valve element <NUM> to a valve opening position by a decrease in a value of the electric current applied to the solenoid <NUM>, and to instantaneously restore from the maximum energized state of the maximum duty to a less-energized state, the so-called duty control. By moving the CS valve element <NUM> in the valve opening direction in a non-energized state of the capacity control valve V1, it is possible to make the control pressure Pc and the suction pressure Ps more easily match with each other.

As a modified example of the capacity control valve V1 of the first embodiment, as shown in <FIG>, an O ring <NUM> serving as a seal portion that seals a part between the guide hole 10c and the small diameter portion 51c of the CS valve element <NUM> may be provided on the axially opposite side of the solenoid <NUM>, that is, in an axially left end portion of the valve housing <NUM>. According to this, the discharge fluid of the discharge pressure Pd applied to the pressure receiving surface 51d of the CS valve element <NUM> is prevented from intruding the valve housing <NUM> through the guide hole 10c. Thus, it is possible to enhance a controlling property of the control pressure Pc. By substantially fixing the O ring <NUM> by a fixing member <NUM> provided in an axially left end of the valve housing <NUM>, it is possible to maintain a seal property irrespective of the actions of the CS valve element <NUM>.

Next, a capacity control valve according to a second embodiment of the present invention will be described with reference to <FIG>. Duplicated description for the same configurations as the first embodiment is omitted.

In a capacity control valve V2 of the second embodiment, as shown in <FIG> and <FIG>, a CS valve element <NUM> serving as a valve element is a stepped and pillar-shaped body formed by integrating a large diameter portion 251b in which a step portion 251a is formed in an axially left end and a small ter portion 251c provided continuously to the axially left side of the large diameter portion 251b, the small diameter portion having a smaller diameter than the large diameter portion 251b, and also serves as a rod arranged to pass through a coil <NUM> of a solenoid <NUM>. The small diameter portion 251c has a constriction portion 251e having a smaller diameter than an axially left end of the small diameter portion 251c in a part which is continuous to the step portion 251a of the large diameter portion 251b. Thus, a flow passage having a constant section is ensured at the time of opening a CS valve <NUM>.

In the second embodiment, as a valve housing, a first valve housing <NUM> and a second valve housing <NUM> inserted into this first valve housing <NUM> are mainly formed. In the first valve housing <NUM>, a Ps port <NUM> serving as a suction port which communicates with a suction chamber of a variable displacement compressor is formed. In the second valve housing <NUM>, a Pc port <NUM> serving as a control port which communicates with a control chamber of the variable displacement compressor is formed. In the first valve housing <NUM>, a recessed portion 210e in which the radially inner side of an axially left end is recessed to the axially right side is formed, and an axially right end portion of the second valve housing <NUM> is integrally connected and fixed in a substantially sealed state by being inserted from the axially left side.

Inside the first valve housing <NUM>, a first valve chamber <NUM> communicating with the Ps port <NUM>, the first valve chamber in which an axially left end portion of the large diameter portion 251b of the CS valve element <NUM> is arranged reciprocatably in the axial direction is formed. Inside the second valve housing <NUM>, a second valve chamber <NUM> communicating with the Pc port <NUM>, the second valve chamber in which the small diameter portion 251c of the CS valve element <NUM> is arranged reciprocatably in the axial direction is formed.

On an inner peripheral surface of the first valve housing <NUM>, a valve hole 210b providing communication between the first valve chamber <NUM> and the second valve chamber <NUM>, the valve hole into which the small diameter portion 251c of the CS valve element <NUM> is inserted is formed. On the inner peripheral surface of the first valve housing <NUM>, a CS valve seat 210a is formed at an opening end edge of the valve hole 210b on the first valve chamber <NUM> side. Further, on the inner peripheral surface of the first valve housing <NUM>, a guide hole 210f with which an outer peripheral surface of the large diameter portion 251b of the CS valve element <NUM> is slidable in a substantially sealed state is formed on the solenoid <NUM> side of the CS valve seat 210a and the first valve chamber <NUM>. Between an inner peripheral surface of the guide hole 210f and the outer peripheral surface of the large diameter portion 251b of the CS valve element <NUM>, a minute gap is formed by slightly separating in the radial direction. The CS valve element <NUM> is smoothly movable with respect to the first valve housing <NUM> in the axial direction.

On an inner peripheral surface of the second valve housing <NUM>, a guide hole 211a with which an outer peripheral surface of a sliding rod <NUM> which is a separate body being separated from and facing the CS valve element <NUM> in the axial direction is slidable in a substantially sealed state is formed on the axially left side of the second valve chamber <NUM>, that is, on the axially opposite side of the solenoid <NUM>. Between an inner peripheral surface of the guide hole 211a and the outer peripheral surface of the sliding rod <NUM>, a minute gap is formed by slightly separating in the radial direction. The sliding rod <NUM> is smoothly movable with respect to the second valve housing <NUM> in the axial direction. The sliding rod <NUM> is arranged at a position coaxial to the CS valve element <NUM>.

An axially left end portion of the sliding rod <NUM> projects to the axially left side from the guide hole 211a of the second valve housing <NUM>, and a pressure receiving surface 252a serving as a pressure receiving portion that receives discharge pressure Pd of a discharge chamber of the variable displacement compressor is formed in an axially left end. A support cap <NUM> is inserted onto an axially right end portion of the sliding rod <NUM> arranged in the second valve chamber <NUM> from the axially right side.

Between the sliding rod <NUM> and the CS valve element <NUM>, a coil spring <NUM> serving as a biassing member is placed. In detail, the coil spring <NUM> is arranged in the second valve chamber <NUM>, and held in a state where an axially left end of the coil spring <NUM> is abutted with an axially right end surface of a flange portion 254a extending to the radially outer side from an axially left end of the support cap <NUM>, and an axially right end of the coil spring <NUM> is abutted with an axially left end surface of a support plate <NUM> fitted onto the small diameter portion 251c of the CS valve element <NUM>. That is, regarding the sliding rod <NUM> and the CS valve element <NUM>, axial end portions opposing each other are connected separably via the coil spring <NUM>.

The discharge pressure Pd of a discharge fluid applied to the pressure receiving surface 252a having a pressure receiving area B which is equal to a sectional area of the sliding rod <NUM> is occasionally changed in accordance with a discharge amount of the variable displacement compressor required from the air conditioning system. Therefore, force FPd applied to the CS valve element <NUM> to the axially right side is changed in accordance with the discharge pressure Pd. In a case where an electric current I energized in the solenoid <NUM> is constant, as shown by a solid graph line in <FIG>, the force FPd applied to the CS valve element <NUM> to the axially right side from the sliding rod <NUM> via the coil spring <NUM> is changed in accordance with the discharge pressure Pd.

In detail, in a state where the discharge pressure Pd is low, as shown in <FIG>, by pressing the sliding rod <NUM> to the axially left side by bias force of the coil spring <NUM>, an axially left end of the flange portion 254a of the support cap <NUM> inserted onto the sliding rod <NUM> is abutted with an inner surface of the second valve chamber <NUM> of the second valve housing <NUM>. When the discharge pressure Pd is increased from this state, the sliding rod <NUM> starts moving to the axially right side against the bias force of the coil spring <NUM>. When the discharge pressure becomes predetermined discharge pressure Pd, an axially right end of the support cap <NUM> moved together with the sliding rod <NUM> is abutted with an axially left end of the CS valve element <NUM>, that is, an axially left end of the small diameter portion 251c (see <FIG>). According to this, in a region from start of moving the axially right end of the support cap <NUM> before the axially right end is abutted with the axially left end of the CS valve element <NUM>, that is, in a buffering region before an inflection point C in <FIG>, the bias force of the coil spring <NUM> becomes resistance of force of moving the sliding rod <NUM> to the axially right side by an increase in the discharge pressure Pd. Thus, force in accordance with the discharge pressure Pd is not easily applied to the CS valve element <NUM>. After the inflection point C in <FIG>, since the state where the axially right end of the support cap <NUM> is abutted with the axially left end of the CS valve element <NUM> is maintained, the compression scale of the coil spring <NUM> is not changed, and the bias force of the coil spring <NUM> becomes constant with respect to an increase in the force in accordance with the discharge pressure Pd. Thus, the force in accordance with the discharge pressure Pd is more easily applied to the CS valve element <NUM>.

By combining actions of the CS valve element <NUM> driven by the solenoid <NUM> and actions of the sliding rod <NUM> by the force in accordance with the discharge pressure Pd, it is possible to correct actions of the CS valve element <NUM>. Thus, control characteristics by correction using the discharge pressure Pd are more easily appropriately changed. By changing a separation distance between the sliding rod <NUM> and the CS valve element <NUM> or a spring constant of the coil spring <NUM>, the control characteristics by correction may be appropriately changed.

By making a valve opening portion area A where the step portion 251a of the CS valve element <NUM> and the CS valve seat 210a are brought into contact with and separated from each other and the pressure receiving area B of the sliding rod <NUM> substantially the same as each other, it is possible to cancel an influence of the control pressure Pc applied to the CS valve element <NUM>. By forming the CS valve element <NUM> and the sliding rod <NUM> separately, it is possible to freely set the valve opening portion area A and the pressure receiving area B.

As a modified example of the capacity control valve V2 of the second embodiment, as shown in <FIG>, an O ring <NUM> serving as a seal portion that seals a part between the guide hole 211a and the sliding rod <NUM> may be provided on the axially opposite side of the solenoid <NUM>, that is, in an axially left end portion of the second valve housing <NUM>. According to this, the discharge fluid of the discharge pressure Pd applied to the pressure receiving surface 252a of the sliding rod <NUM> is prevented from intruding the first valve housing <NUM> and the second valve housing <NUM> through the guide hole 211a. Thus, it is possible to enhance a controlling property of the control pressure Pc. By substantially fixing the O ring <NUM> by a fixing member <NUM> provided in an axially left end of the second valve housing <NUM>, it is possible to maintain a seal property irrespective of the actions of the sliding rod <NUM>.

A capacity control valve according to a third embodiment of the present invention will be described with reference to <FIG>. Duplicated description for the same configurations as the second embodiment is omitted.

In a capacity control valve V3 of the third embodiment, as shown in <FIG> and <FIG>, a CS valve element <NUM> serving as a valve element is a stepped and pillar-shaped body formed by integrating a large diameter portion 351b in which a step portion 351a is formed in an axially left end and a small diameter portion 351c provided continuously to the axially left side of the large diameter portion 351b, the small diameter portion having a smaller diameter than the large diameter portion 351b, and also serves as a rod arranged to pass through a coil <NUM> of a solenoid <NUM>. By forming the small diameter portion 351c in the CS valve element <NUM>, a flow passage having a constant section is ensured at the time of opening a CS valve <NUM>.

Between a sliding rod <NUM> which is a separate body being separated from and facing the CS valve element <NUM> in the axial direction and an axially left end of a first valve housing <NUM>, a coil spring <NUM> serving as a biasing member is placed. In detail, the coil spring <NUM> is arranged in a second valve chamber <NUM> and held in a state where an axially left end of the coil spring <NUM> is abutted with an axially right end surface of a flange portion 254a formed in a support cap <NUM>, and an axially right end of the coil spring <NUM> is abutted with an axially left end surface of the first valve housing <NUM>. That is, regarding the sliding rod <NUM> and the CS valve element <NUM>, axial end portions opposing each other are arranged connectably and separably.

According to this, as shown in <FIG>, in a region from start of moving an axially right end of the support cap <NUM> before the axially right end is abutted with an axially left end of the CS valve element <NUM>, that is, in a buffering region before an inflection point D in <FIG>, force in accordance with discharge pressure Pd is not applied to a valve opening degree of the CS valve <NUM>. After the inflection point D in <FIG>, since the axially right end of the support cap <NUM> is abutted with an axially left end of the small diameter portion 351c, bias force of the coil spring <NUM> becomes resistance of force of moving the sliding rod <NUM> to the axially right side by an increase in the discharge pressure Pd. Thus, the force in accordance with the discharge pressure Pd is not easily applied to the CS valve element <NUM>.

By combining actions of the CS valve element <NUM> driven by the solenoid <NUM> and actions of the sliding rod <NUM> by the force in accordance with the discharge pressure Pd, it is possible to set a region where the actions of the CS valve element <NUM> are corrected and a region where the actions are not corrected. Thus, control characteristics by correction using the discharge pressure Pd are more easily appropriately changed. By changing a separation distance between the sliding rod <NUM> and the CS valve element <NUM> or a spring constant of the coil spring <NUM>, the control characteristics by correction may be appropriately changed.

As a modified example of the capacity control valve V3 of the third embodiment, as shown in <FIG>, an O ring <NUM> serving as a seal portion that seals a part between a guide hole 211a provided on the axially opposite side of the solenoid <NUM>, that is, in the second valve housing <NUM> and the sliding rod <NUM> may be provided. According to this, a discharge fluid of the discharge pressure Pd applied to a pressure receiving surface 252a of the sliding rod <NUM> is prevented from intruding the first valve housing <NUM> and the second valve housing <NUM> through the guide hole 211a. Thus, it is possible to enhance a controlling property of control pressure Pc. By substantially fixing the O ring <NUM> by a fixing member <NUM> provided in an axially left end of the second valve housing <NUM>, it is possible to maintain a seal property irrespective of the actions of the sliding rod <NUM>.

A capacity control valve according to a fourth embodiment of the present invention will be described with reference to <FIG>. Duplicated description for the same configurations as the first embodiment is omitted.

In a capacity control valve V4 according to the fourth embodiment of the present invention, as shown in <FIG> and <FIG>, a CS valve element <NUM> serving as a valve element is an integrated pillar-shaped body having a substantially constant section and also serves as a rod arranged to pass through a coil <NUM> of a solenoid <NUM>. A pressure receiving surface 451b serving as a pressure receiving portion that receives discharge pressure Pd of a discharge chamber of a variable displacement compressor is formed in an axially right end of a CS valve element <NUM>.

In a valve housing <NUM>, a Ps port <NUM> serving as a suction port which communicates with a suction chamber of the variable displacement compressor, and a Pc port <NUM> serving as a control port which communicates with a control chamber of the variable displacement compressor, and a Pd port <NUM> communicating with the discharge chamber of the variable displacement compressor are formed.

Inside the valve housing <NUM>, a first valve chamber <NUM> in which an axially left end portion of the CS valve element <NUM> is arranged reciprocatably in the axial direction is formed on the axially left side, the Ps port <NUM> extends in the radially inward direction from an outer peripheral surface of the valve housing <NUM> and communicates with the first valve chamber <NUM>, and the Pc port <NUM> extends to the axially right side from the radially inner side of an axially left end of the valve housing <NUM> and communicates with the first valve chamber <NUM>. Inside the valve housing <NUM>, a second valve chamber <NUM> communicating with the Pd port <NUM> is formed on the axially right side, that is, on the solenoid <NUM> side.

On an inner peripheral surface of the valve housing <NUM>, a guide hole 410b passing through between the first valve chamber <NUM> and the second valve chamber <NUM>, the guide hole with which an outer peripheral surface of the axially left end portion of the CS valve element <NUM> is slidable in a substantially sealed state is formed. On the inner peripheral surface of the valve housing <NUM>, a CS valve seat 410a is formed at an opening end edge of the Pc port <NUM> on the first valve chamber <NUM> side. Between an inner peripheral surface of the guide hole 410b and the outer peripheral surface of the CS valve element <NUM>, a minute gap is formed by slightly separating in the radial direction. The CS valve element <NUM> is smoothly movable with respect to the valve housing <NUM> in the axial direction.

The first valve chamber <NUM> and the second valve chamber <NUM> are sealed in a substantially sealed state by a clearance seal serving as a seal portion which is formed by the inner peripheral surface of the guide hole 410b and the outer peripheral surface of the CS valve element <NUM>. Thus, a discharge fluid of the discharge pressure Pd supplied from the Pd port <NUM> to the second valve chamber <NUM> is prevented from intruding the first valve chamber <NUM>. The discharge fluid of the discharge pressure Pd supplied from the Pd port <NUM> to the second valve chamber <NUM> can run round to the back surface side of the CS valve element <NUM> to which a movable iron core <NUM> is inserted, that is, to a pressure receiving surface 451b formed in the axially right end of the CS valve element <NUM> through a gap between an inner peripheral surface of an insertion hole 82a extending in the axial direction in a center post <NUM> which forms the solenoid <NUM>, and the outer peripheral surface of the CS valve element <NUM> inserted into the insertion hole 82a.

Next, actions of the capacity control valve V4, mainly actions of opening and closing a CS valve <NUM> will be described.

First, a non-energized state of the capacity control valve V4 will be described. As shown in <FIG>, in the capacity control valve V4, in a non-energized state, by pressing the movable iron core <NUM> to the axially right side by bias force of a coil spring <NUM>, the CS valve element <NUM> is moved to the axially right side together, an axially left end 451a of the CS valve element <NUM> is separated from the CS valve seat 410a, and the CS valve <NUM> is opened.

At this time, to the CS valve element <NUM>, the bias force Fsp of the coil spring <NUM> and force FPc by control pressure Pc of a control fluid to the CS valve element <NUM> are applied to the axially right side, and force FPd by the discharge pressure Pd of the discharge fluid to the pressure receiving surface 451b of the CS valve element <NUM> is applied to the axially left side. That is, given that the right side is the positive side, force Frod = Fsp + FPc - FPd is applied to the CS valve element <NUM>.

Next, an energized state of the capacity control valve V4 will be described. As shown in <FIG>, in the capacity control valve V4, in an energized state, that is, at the time of normal control, at the time of so-called duty control, when electromagnetic force Fsol generated by applying an electric current to the solenoid <NUM> exceeds the force Frod (i.e., Fsol > Frod), by pulling the movable iron core <NUM> to the axially left side, that is, toward the center post <NUM>, and moving the CS valve element <NUM> fixed to the movable iron core <NUM> to the axially left side together, the axially left end 451a of the CS valve element <NUM> is seated on the CS valve seat 410a, and the CS valve <NUM> is closed.

At this time, to the CS valve element <NUM>, the electromagnetic force Fsol is applied on the axially left side, and the force Frod is applied on the axially right side. That is, given that the right side is the positive side, force Frod - Fsol, in detail, force Fsp + FPc - FPd - Fsol is applied to the CS valve element <NUM>.

The discharge pressure Pd applied to the pressure receiving surface 451b of the CS valve element <NUM> is occasionally changed in accordance with the discharge amount of the variable displacement compressor required from an air conditioning system. Therefore, the force FPd applied to the CS valve element <NUM> to the axially right side is changed in accordance with the discharge pressure Pd. In a case where the electric current I energized in the solenoid <NUM> is constant, as shown by a solid graph line in <FIG>, an opening area of the CS valve <NUM> is decreased in proportion to the discharge pressure Pd.

According to this, in the capacity control valve V4, Pc-Ps control that opens and closes the CS valve <NUM> to supply the control fluid of the control pressure Pc supplied from the Pc port <NUM> to the suction chamber via the Ps port <NUM> and lower the control pressure Pc of the control chamber is performed, and the discharge pressure Pd supplied from the Pd port <NUM>, the discharge pressure being higher pressure than the control pressure Pc and suction pressure Ps can be applied to the pressure receiving surface 451b of the CS valve element <NUM> to the axially left side, that is, in the valve closing direction of the CS valve <NUM>, and used for correction of actions of the CS valve element <NUM>. Therefore, a valve opening degree of the CS valve <NUM> is more easily adjusted and it is possible to let the control pressure Pc of the air conditioning system reach a target value in a short time.

By forming an annular groove on the inner peripheral surface of the guide hole 410b and the outer peripheral surface of the CS valve element <NUM>, a seal property in the clearance seal may be enhanced by a labyrinth effect of the groove.

The embodiments of the present invention are described above with the drawings. However, specific configurations are not limited to these embodiments but the present invention includes changes and additions within the range not departing from the scope of claims <NUM> to <NUM>.

For example, the above embodiments describe that the CS valve element also serves as the rod arranged to pass through the coil <NUM> of the solenoid <NUM>. However, the present invention is not limited to this but the CS valve element may be formed reciprocatably in the axial direction together with a separate rod.

The above embodiments describe that the capacity control valves V1 to V4 are formed as a normal open type in which the CS valve element is biased in the valve opening direction of the CS valve by the coil spring <NUM>. However, the present invention is not limited to this but the capacity control valves may be formed as a normal close type in which the CS valve element is biased in the valve closing direction of the CS valve by the coil spring <NUM>.

The above embodiments describe the configuration that the Pc port <NUM> is formed on the axially left side of the Ps port <NUM>. However, arrangement may be switched in such a manner that the Pc port <NUM> is formed on the axially right side of the Ps port <NUM>. In this case, a shape or arrangement of the CS valve element and the CS valve seat are appropriately changed.

The above first to third embodiments describe that the CS valve element or the axially left end portion of the sliding rod in which the pressure receiving surface is formed projects to the axially left side from the guide hole. However, the present invention is not limited to this but the CS valve element or the axially left end of the sliding rod, that is, the pressure receiving surface may be always arranged inside the guide hole.

The above first to third embodiments describe the configuration that the O ring serving as the seal portion that seals the part between the guide hole and the CS valve element or the sliding rod is provided as the modified example. However, the present invention is not limited to this but the seal portion may be freely formed as long as the discharge fluid of the discharge pressure Pd applied to the pressure receiving surface can be prevented from intruding the valve housing.

In the above second embodiment, the sliding rod <NUM> and the CS valve element <NUM> may be not abutted but always separated from each other in the axial direction.

In the above third embodiment, the coil spring <NUM> is not limited to be placed between the sliding rod <NUM> and the axially left end of the first valve housing <NUM>. The axially right end of the coil spring <NUM> may be abutted with an inward flange portion formed on the inner peripheral surface of the second valve housing <NUM>, for example.

Claim 1:
A capacity control valve (V4) comprising:
a valve housing (<NUM>) provided with a suction port (<NUM>) through which a suction fluid of suction pressure (Ps) passes, and a control port (<NUM>) through which a control fluid of control pressure (Pc) passes;
a valve element (<NUM>) configured to be driven by a solenoid (<NUM>);
a spring (<NUM>) that biases the valve element (<NUM>) in a direction opposite to a driving direction by the solenoid (<NUM>); and
a CS valve (<NUM>) formed by a CS valve seat (410a) and the valve element (<NUM>) and configured for opening and closing a communication between the control port (<NUM>) and the suction port <NUM>) by a movement of the valve element (<NUM>), wherein
the control pressure (Pc) is controlled by opening and closing the CS valve (<NUM>), and
the capacity control valve (V4) further comprises a pressure receiving portion (451b) to which force in accordance with discharge pressure (Pd) is applied in a valve closing direction of the CS valve (<NUM>), characterized in that
the pressure receiving portion (451b) is positioned on a side of the solenoid (<NUM>) with respect to the CS valve seat (410a) in an axial direction,
a contact portion of the valve element (<NUM>) which is brought into contact with the CS valve seat (410a) is positioned on a side of the solenoid (<NUM>) with respect to the CS valve seat (410a) in the axial direction,
the capacity control valve (V4) further comprises a space formed on a back surface side of the valve element (<NUM>) to which a movable iron core of the solenoid (<NUM>) is inserted, and a gap formed between an inner peripheral surface of an insertion hole (82a) extending in the axial direction in a center post which forms the solenoid (<NUM>) and an outer peripheral surface of the valve element (<NUM>) inserted into the insertion hole (82a), and
the pressure receiving portion (451b) is arranged so as to face the space formed on the back surface side of the valve element (<NUM>).