valve

Abstract

The present invention provides a valve having high controllability.　A valve V1 is equipped with: a valve housing 10 that has an inflow port 40b and an outflow port 11 formed therein; a valve body 51 that is driven by a drive source 80; a spring 85 that biases the valve body 51 in the opposite direction from the direction of driving by the drive source 80; and a poppet valve 50 that is constituted from the valve body 51 and a valve seat 40a formed on the edge of a through-flow passage 40b. The movement of the valve body 51 is used to control the flow rate. A flow passage C1 on the downstream side of the poppet valve 50 is provided with a decrease region where the flow passage cross-sectional area exhibits a progressive decrease toward the downstream side.

Description

[Technical field]

[0001] The present invention relates to a valve for variably controlling a working fluid, and more particularly to a valve for controlling the discharge volume of a variable displacement compressor used in an automotive air conditioning system in accordance with pressure. [Background technology]

[0002] A variable displacement compressor used in air conditioning systems for automobiles and the like includes a rotating shaft driven by an engine, a swash plate connected to the rotating shaft with a variable inclination angle, and a compression piston connected to the swash plate. The variable displacement compressor controls the amount of fluid discharged by changing the stroke amount of the piston by changing the inclination angle of the swash plate. The inclination angle of the swash plate can be continuously changed by appropriately controlling the pressure in the control chamber using the suction pressure Ps of the suction chamber that draws in the fluid, the discharge pressure Pd of the discharge chamber that discharges the fluid pressurized by the piston, and the control pressure Pc of the control chamber that houses the swash plate, using a capacity control valve that is opened and closed by electromagnetic force.

[0003] When the variable displacement compressor is in continuous operation, the displacement control valve is energized and controlled by the control computer. The electromagnetic force generated by the solenoid moves the valve body in the axial direction, and the valve provided between the discharge port through which the discharge fluid at discharge pressure Pd passes and the control port through which the control fluid at control pressure Pc passes is opened and closed to perform normal control to adjust the control pressure Pc in the control chamber of the variable displacement compressor.

[0004] During normal control of the capacity control valve, the pressure in the control chamber in the capacity control compressor is appropriately controlled, and the inclination angle of the swash plate relative to the rotating shaft is continuously changed to change the stroke amount of the piston and control the amount of fluid discharged into the discharge chamber, thereby adjusting the air conditioning system to achieve the target cooling capacity.

[0005] Also, some displacement control valves control the flow rate of fluid flowing from a control port to a suction port by opening and closing a poppet valve provided between the control port and the suction port (see Patent Document 1). Such displacement control valves control the control pressure Pc in a control chamber of a variable displacement compressor by utilizing the pressure difference between the control pressure Pc and a suction pressure Ps that is lower than the control pressure Pc. The control chamber of the variable displacement compressor is connected to the discharge chamber of the variable displacement compressor via an orifice, and the control pressure Pc is adjusted by constantly supplying a high discharge pressure Pd to the control chamber through the orifice. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-075054 A (pages 8 to 10, Figure 2) Summary of the Invention [Problem to be solved by the invention]

[0007] The displacement control valve of Patent Document 1 uses the pressure difference between the control pressure Pc, which is lower than the discharge pressure Pd, and the suction pressure Ps to control the flow rate of the fluid by opening and closing the poppet valve, so that the flow rate of the fluid passing through the poppet valve can be reduced, but even if a preset current is input to the solenoid, the stroke of the valve body varies due to the influence of the discharge pressure Pd, which is constantly supplied through an orifice to adjust the control pressure Pc, and the opening of the valve may deviate from the target value. From the research of the inventors, it was found that the stroke of the valve body can be influenced by passing a refrigerant with a flow velocity close to the speed of sound through the poppet valve, and by utilizing this, the above-mentioned variation can be suppressed.

[0008] The present invention has been made in consideration of such problems, and has an object to provide a valve with high controllability. [Means for solving the problem]

[0009] In order to solve the above problems, the valve of the present invention comprises: a valve housing having an inlet port and an outlet port formed therein; A valve body driven by a drive source; a spring that biases the valve body in a direction opposite to a drive direction of the drive source; A poppet valve including a valve seat formed on an edge of a through-flow passage and the valve body, the poppet valve controlling a flow rate by movement of the valve body, The flow passage downstream of the poppet valve is provided with a decreasing region in which the flow passage cross-sectional area tends to decrease toward the downstream side. According to this, when the fluid passing through the poppet valve is a supersonic flow, the flow velocity of the fluid passing through the reduction region in the flow path downstream of the poppet valve decreases, and the downstream pressure of the poppet valve increases. As a result, a force in the valve closing direction acts on the valve body, the valve closing characteristics are improved, and the poppet valve can be closed with a small current value. Also, when the fluid passing through the poppet valve is a subsonic flow, the flow velocity of the fluid passing through the reduction region in the flow path downstream of the poppet valve increases, and the downstream pressure decreases. As a result, a force in the valve opening direction acts on the valve body, and the effect of the pressure of the upstream fluid on the force due to the back pressure acting on the valve body can be suppressed, and the variation in the stroke of the valve body relative to the current value input to the solenoid can be suppressed. As a result, the opening degree of the poppet valve can be accurately adjusted.

[0010] The decreasing region may have a constant minimum flow passage cross-sectional area regardless of the stroke of the valve body. This allows the pressure of the fluid in the valve chamber after passing through the decreasing region to be always stable.

[0011] The decreasing region may have a flow passage cross-sectional area that decreases continuously. This makes it possible to stabilize the flow of fluid passing through the reduction region in the flow passage downstream of the poppet valve and eliminate stagnation.

[0012] The poppet valve may be configured by the valve seat having an inclined cross-sectional shape and the valve body having a curved cross-sectional shape. This allows the flow of fluid passing through the poppet valve to be stabilized in the tangential direction when the valve disc is in the closed or throttle position.

[0013] The inclined shape may be linear. This allows the flow of fluid passing through the poppet valve to be more stable in the tangential direction when the valve body is in the closed or throttle position.

[0014] The inclined surface that constitutes the valve seat may be continuous with the inclined surface that constitutes the reduced area. This makes it easier to increase the flow passage cross-sectional area upstream of the reduction region.

[0015] The inclined surface constituting the valve seat may be formed on a valve seat member separate from the valve housing, and the inclined surface constituting the reduced area may be formed on the valve housing. This makes it easy to set the flow path cross-sectional area and form the reduced area easily. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a cross-sectional view showing a state in which a CS valve is opened in a non-energized state of the capacity control valve according to the first embodiment of the present invention. [Diagram 2] 4 is a cross-sectional view showing a state in which a valve seat member is press-fitted into a valve housing of the displacement control valve of the first embodiment. FIG. [Diagram 3] 4 is an enlarged cross-sectional view showing a reduced region in a flow passage downstream of a CS valve in a capacity control valve of the first embodiment in an energized state (during normal control). FIG. [Figure 4] FIG. 1A is a diagram showing a schematic diagram of the valve closing characteristics in a supersonic flow of the capacity control valve of the first embodiment in which the flow path cross-sectional area tends to decrease, and FIG. 1B is a diagram showing a schematic diagram of the valve closing characteristics of the comparative example in which the flow path cross-sectional area is constant. [Diagram 5]FIG. 1A is a diagram showing a schematic diagram of the valve closing characteristics in a subsonic flow of the capacity control valve of the first embodiment in which the flow path cross-sectional area tends to decrease, and FIG. 1B is a diagram showing a schematic diagram of the valve closing characteristics of a comparative example in which the flow path cross-sectional area is constant. [Figure 6] FIG. 11 is a cross-sectional view showing a state in which a CS valve is opened in a non-energized state of a capacity control valve according to a second embodiment of the present invention. [Figure 7] FIG. 11 is a cross-sectional view showing a state in which a valve seat member is press-fitted into a valve housing of a displacement control valve according to a second embodiment. [Figure 8] FIG. 11 is an enlarged cross-sectional view showing a reduced region in a flow passage downstream of a CS valve in a capacity control valve according to a second embodiment in an energized state (during normal control). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A valve according to the present invention will be described below based on an embodiment. Note that although the embodiment will be described using a capacity control valve as an example, the present invention can also be applied to other uses. EXAMPLES

[0018] A displacement control valve according to a first embodiment will be described with reference to Fig. 1 to Fig. 3. In the following description, the left and right sides as viewed from the front side of Fig. 1 will be referred to as the left and right sides of the displacement control valve. In particular, the left side of the drawing where the valve housing 10 is arranged will be referred to as the left side of the displacement control valve, and the right side of the drawing where the solenoid 80 is arranged will be referred to as the right side of the displacement control valve.

[0019] The capacity control valve of the present invention is incorporated in a variable capacity compressor (not shown) used in the air conditioning system of an automobile or the like, and controls the discharge volume of the variable capacity compressor by variably controlling the pressure of a working fluid (hereinafter simply referred to as "fluid") which is a refrigerant, thereby adjusting the air conditioning system to achieve a target cooling capacity.

[0020] First, the variable displacement compressor will be described. The variable displacement compressor has a casing that includes a discharge chamber, a suction chamber, a control chamber, and multiple cylinders. The variable displacement compressor is provided with a communication passage that directly connects the discharge chamber and the control chamber, and this communication passage is provided with a fixed orifice 9 for balancing the pressures of the discharge chamber and the control chamber (see FIG. 1).

[0021] The variable displacement compressor includes a rotating shaft, a swash plate, and a plurality of pistons. The rotating shaft is driven to rotate by an engine (not shown) installed outside the casing. The swash plate is connected to the rotating shaft in a control chamber so as to be tiltable by a hinge mechanism. The pistons are connected to the swash plate and fitted in their respective cylinders so as to be capable of reciprocating motion. Using a displacement control valve V1 that is driven to open and close by an electromagnetic force, the inclination angle of the swash plate is continuously changed by appropriately controlling the pressure in the control chamber using the suction pressure Ps of the suction chamber that draws in the fluid, the discharge pressure Pd of the discharge chamber that discharges the fluid pressurized by the pistons, and the control pressure Pc of the control chamber that accommodates the swash plate, thereby changing the stroke amount of the pistons and controlling the discharge amount of the fluid.

[0022] 1, the displacement control valve V1 of the first embodiment, which is incorporated in a variable displacement compressor, adjusts the current flowing through a coil 86 constituting a solenoid 80 as a drive source to control the opening and closing of a CS valve 50 as a poppet valve in the displacement control valve V1. This controls the fluid flowing from the control chamber to the suction chamber, thereby variably controlling the control pressure Pc in the control chamber. Note that the discharge fluid at the discharge pressure Pd of the discharge chamber is constantly supplied to the control chamber via a fixed orifice 9, and the control pressure Pc in the control chamber can be increased by closing the CS valve 50 in the displacement control valve V1.

[0023] In the capacity control valve V1 of the first embodiment, the CS valve 50 is composed of a CS valve body 51 as a valve body and a CS valve seat 40a as a valve seat. The CS valve seat 40a is formed in a cylindrical valve seat member 40 that is press-fitted and fixed in a recess 10a of the valve housing 10. The CS valve 50 opens and closes when an abutment portion 51a formed at the axial left end of the CS valve body 51 moves axially toward and away from the CS valve seat 40a.

[0024] Next, the structure of the displacement control valve V1 will be described. As shown in Fig. 1, the displacement control valve V1 is mainly composed of a valve housing 10, a valve seat member 40, a CS valve body 51, and a solenoid 80. The valve housing 10 and the valve seat member 40 are made of a metal material. The CS valve body 51 is arranged in the valve housing 10 so as to be able to reciprocate axially. The solenoid 80 is connected to the valve housing 10 and applies a driving force to the CS valve body 51.

[0025] As shown in Fig. 1, the CS valve body 51 is made of a metal material or a resin material. The CS valve body 51 is composed of a large diameter portion 51b and a small diameter portion 51c. The large diameter portion 51b is a columnar body with a constant cross section. The small diameter portion 51c extends axially rightward from the inner diameter side of the axial right end of the large diameter portion 51b. The CS valve body 51 also serves as a rod that is disposed to pass through the coil 86 of the solenoid 80.

[0026] An abutment portion 51a having a curved cross-sectional shape that bulges toward the CS valve seat 40a is formed on the left axial end face of the CS valve body 51, i.e., the left axial end face of the large diameter portion 51b. More specifically, the curved shape of the abutment portion 51a is formed by a part of a sphere having a constant radius of curvature. Note that the abutment portion 51a does not have to be formed by a part of a sphere having a constant radius of curvature as long as the curved shape allows the abutment portion 51a to seat on the CS valve seat 40a.

[0027] As shown in FIG. 1, the solenoid 80 is mainly composed of a casing 81, a center post 82, the CS valve body 51, a movable iron core 84, a coil spring 85, and an exciting coil 86. The casing 81 has an opening 81a that opens to the left in the axial direction. The center post 82 is inserted into the opening 81a of the casing 81 from the left in the axial direction and is disposed between the inner diameter side of the casing 81 and the inner diameter side of the valve housing 10, and has a substantially cylindrical shape. The CS valve body 51 is inserted into the center post 82 and is capable of reciprocating in the axial direction, and its left axial end is disposed in the valve housing 10. The right axial end of the CS valve body 51 is inserted into and fixed to the movable iron core 84. The coil spring 85 is disposed between the center post 82 and the movable iron core 84, and biases the movable iron core 84 to the right in the axial direction, which is the valve opening direction of the CS valve 50. The coil 86 is wound around the outside of the center post 82 via a bobbin.

[0028] The center post 82 includes a cylindrical portion 82b and an annular flange portion 82d. The cylindrical portion 82b is formed from a rigid body that is a magnetic material such as iron or silicon steel, and is formed with an insertion hole 82c that extends in the axial direction and through which the CS valve body 51 is inserted. The flange portion 82d extends radially outward from the outer circumferential surface of the left axial end of the cylindrical portion 82b.

[0029] As shown in Fig. 1, a valve housing 10 is formed with a Ps port 11 as an outflow port. The Ps port 11 penetrates radially and communicates with the suction chamber of the variable displacement compressor. A recess 10a is formed on the left side of the valve housing 10 in the axial direction. A cylindrical valve seat member 40 is press-fitted into the recess 10a from the left in the axial direction. A Pc port is formed in the valve housing 10 as an inflow port. The Pc port communicates with the control chamber of the variable displacement compressor via a through hole 40b that penetrates the valve seat member 40 in the axial direction by the valve seat member 40 being press-fitted and fixed into the recess 10a.

[0030] A valve chamber 20 is formed inside the valve housing 10, and a contact portion 51a of a CS valve element 51 is arranged so as to be able to reciprocate axially inside the valve chamber 20. In addition, the Ps port 11 extends radially inward from the outer circumferential surface of the valve housing 10 and communicates with the valve chamber 20.

[0031] Thus, inside the valve housing 10, the through hole 40b of the valve seat member 40, the valve chamber 20, and the Ps port 11 define a flow passage that communicates between the control chamber and the suction chamber of the variable displacement compressor.

[0032] A guide hole 10c is formed in the inner peripheral surface of the valve housing 10. An outer peripheral surface 51d (see FIG. 3) of the large diameter portion 51b of the CS valve element 51 is slidable in the guide hole 10c axially to the right of the valve chamber 20, where the solenoid 80 is attached. A minute gap is formed between the inner peripheral surface of the guide hole 10c and the outer peripheral surface 51d of the large diameter portion 51b of the CS valve element 51 by being slightly separated in the radial direction, so that the CS valve element 51 can move smoothly relative to the valve housing 10 in the axial direction.

[0033] As shown in FIG. 2, the recess 10a of the valve housing 10 is formed so that its inner diameter R1 is larger than the inner diameter R2 of the valve chamber 20 (R1>R2), so that the bottom surface of the recess 10a forms a receiving portion 10b that can abut against the flat surface 40c on the axial right side of the valve seat member 40.

[0034] 1, the valve housing 10 has a recess 10d formed on its axial right side that recesses axially leftward, into which a flange portion 82d of a center post 82 is inserted and fixed from the axial right in a substantially sealed manner. Furthermore, the casing 81 is inserted and fixed from the axial right in a substantially sealed manner, thereby being connected together.

[0035] In this manner, with the valve housing 10, center post 82, and casing 81 connected together, the right axial end face of the valve housing 10 and the right axial side face of flange portion 82d of center post 82 abut against the bottom surface of recess 81b formed on the left axial side of the casing 81. Also, the bottom surface of recess 10d of the valve housing 10 and the left axial end face of the center post 82 are separated in the axial direction to form a gap.

[0036] Further, a through hole 21 is formed in the valve housing 10. The through hole 21 extends in the axial direction between the axial left end face of the valve housing 10 and the bottom of the recess 10d. The through hole 21 is composed of a small diameter hole portion 211 and a large diameter hole portion 212. The axial left end of the small diameter hole portion 211 is connected to the control chamber of the variable displacement compressor. The large diameter hole portion 212 extends continuously from the axial right end of the small diameter hole portion 211 and has a larger diameter than the small diameter hole portion 211. The axial right end of the large diameter hole portion 212 opens into a gap formed between the bottom face of the recess 10d and the axial left end face of the center post 82. The small diameter hole portion 211 of the through hole 21 and the through hole 40b of the valve seat member 40 are supplied with a control fluid of a control pressure Pc from the control chamber of the variable displacement compressor.

[0037] A ball-shaped operating valve element 31 and a return spring 32 are disposed in the large diameter hole portion 212 of the through hole 21. The right axial end of the operating valve element 31 is fixed to the left axial end face of the center post 82 and the left axial end of the operating valve element 31 abuts against the right axial direction of the operating valve element 31. The operating valve element 31 is biased axially leftward by the return spring 32. The operating valve element 31 and the return spring 32 constitute a pressure operated valve 30 that controls communication between a control chamber of the variable displacement compressor and a space S inside the casing 81 in the through hole 21.

[0038] For convenience of explanation, illustration is omitted, but when the control pressure Pc is high, the operating valve element 31 of the pressure operated valve 30 moves axially rightward against the biasing force of the return spring 32 and the pressure of the fluid in the space S inside the casing 81, and opens by being separated from the valve seat 213 having a cross-sectionally inclined shape formed at the connecting portion between the axial right end of the small diameter hole portion 211 of the through hole 21 and the axial left end of the large diameter hole portion 212. As a result, the control chamber of the variable displacement compressor and the space S inside the casing 81 communicate with each other via the through hole 21, and the control fluid of the control pressure Pc is supplied from the control chamber of the variable displacement compressor to the space S inside the casing 81 through the through hole 21, and the difference between the pressure of the fluid in the space S inside the casing 81 and the pressure of the control fluid in the through hole 40b of the valve seat member 40 becomes small, so that the CS valve element 51 can be smoothly operated axially leftward, i.e., in the valve closing direction, and the responsiveness of the variable displacement compressor to control at high output can be improved.

[0039] In the valve housing 10, the minute gap between the inner surface of the guide hole 10c and the outer surface of the large diameter section 51b of the CS valve body 51 functions as a throttle, allowing the fluid in the space S inside the casing 81 to slowly escape to the Ps port 11, and when not in use for an extended period of time, the pressure difference between the fluid pressure in the valve chamber 20 and the fluid pressure in the space S inside the casing 81 is maintained small.

[0040] Here, the valve seat member 40 will be described. As shown in Fig. 2, the valve seat member 40 is made of a metal material harder than the metal material used for the valve housing 10. Furthermore, the valve seat member 40 is made of a material different from that of the CS valve body 51.

[0041] The valve seat member 40 is cylindrical and has a through hole 40b penetrating in the axial direction. At the right end of the valve seat member 40 in the axial direction, from the outer diameter side to the inner diameter side, there is formed an annular flat surface 40c and a CS valve seat 40a having a cross-sectional inclined shape that is connected to the flat surface 40c from the inner diameter side and gradually reduces in diameter toward the left in the axial direction. That is, the CS valve seat 40a is formed on the edge of the through hole 40b as a through flow passage, and is constituted by a tapered surface in which a cross-sectional linear inclined surface extends in the circumferential direction.

[0042] Furthermore, by abutting the flat surface 40c on the axial right side of the valve seat member 40 against the receiving portion 10b formed by the bottom surface of the recess 10a in the axial direction (see FIG. 3), it is possible to regulate the degree of insertion of the valve seat member 40 into the recess 10a and to improve the sealing performance between the valve housing 10 and the valve seat member 40. At this time, the outer diameter end of the tapered surface constituting the CS valve seat 40a is arranged so as to be continuous with the axial left end of the inner circumferential surface 10e of the valve chamber 20 of the valve housing 10.

[0043] As a result, a flow path on the downstream side of the CS valve 50 extending to the opening on the valve chamber 20 side of the Ps port 11 is formed by a flow path C1 formed between the tapered surface constituting the CS valve seat 40a of the valve seat member 40 and the abutting portion 51a of the CS valve body 51, and a flow path C2 formed between the tapered surface constituting the CS valve seat 40a, the outer circumferential surface 51d of the large diameter portion 51b of the CS valve body 51, and between the inner circumferential surface 10e of the valve housing 10 and the outer circumferential surface 51d of the large diameter portion 51b of the CS valve body 51 (see FIG. 3). Note that FIG. 3 shows a state in which the CS valve body 51 has been stroked to a throttling position near the closed position during normal control of the displacement control valve V1.

[0044] In this embodiment 1, the flow path C1 constitutes a decreasing region in which the flow path cross-sectional area A2 between the tapered surface constituting the CS valve seat 40a and the outer diameter end of the abutting portion 51a of the CS valve body 51 is smaller than the flow path cross-sectional area A1 between the inner diameter end of the tapered surface constituting the CS valve seat 40a and the abutting portion 51a of the CS valve body 51 (A1>A2), and the flow path cross-sectional area tends to decrease (dA<0) downstream. Also, the flow path C2 has a constant flow path cross-sectional area A3 because the inner peripheral surface 10e of the valve housing 10 and the outer peripheral surface 51d of the CS valve body 51 are arranged in parallel. During normal control of the capacity control valve V1, in the state shown in FIG. 3 where the CS valve body 51 has been stroked to the throttling position, the flow path cross-sectional area A2 on the downstream side of the flow path C1 and the flow path cross-sectional area A3 of the flow path C2 are the same (A2=A3). However, this is not limited to the above, and the flow path cross-sectional area A3 on the upstream side of the flow path C2 may be smaller than the flow path cross-sectional area A2 on the downstream side of the flow path C1 (A2>A3).

[0045] The decreasing region is formed within the stroke range of the contact portion 51a of the CS valve body 51 in the flow passage downstream of the CS valve 50.

[0046] The cross-sectional area of ​​the flow passage C1 decreases continuously downstream.

[0047] Next, we will explain the change in flow velocity and pressure of the fluid passing through the flow paths C1 and C2 downstream of the CS valve 50. Note that we will explain the control pressure Pc as being controlled within a range in which the above-mentioned pressure-actuated valve 30 is maintained closed. Regarding the effect of area change in an isentropic flow, the relational equation between cross-sectional area and pressure is shown below.

[0048]

number

[0049] p: pressure γ: specific heat ratio M: Mach number A: Area

[0050] Based on this relational expression between the cross-sectional area and the pressure, when the pressure difference between the control pressure Pc in the through hole 40b of the valve seat member 40 and the suction pressure Ps in the Ps port 11, i.e., the Pc-Ps pressure difference, is large and the fluid passing through the CS valve 50 is a supersonic flow (M>1), the fluid passing through the flow path C1, which constitutes a decreasing region in which the flow path cross-sectional area tends to decrease (dA<0) as it goes downstream in the flow path on the downstream side of the CS valve 50, decreases in flow velocity and increases in pressure. In addition, by passing through flow path C2, which is continuous with the downstream of flow path C1 and has a constant flow path cross-sectional area, the fluid flows stably with almost no change in flow velocity and pressure, and flows into the Ps port 11 (see FIG. 3).

[0051] On the other hand, when the Pc-Ps differential pressure is small and the fluid passing through the CS valve 50 is a subsonic flow (M<1), the fluid passing through flow path C1, which constitutes a reduction region in the flow path downstream of the CS valve 50, increases in flow velocity and decreases in pressure. In addition, by passing through flow path C2, which is continuous with the downstream of flow path C1 and has a constant flow path cross-sectional area, the fluid flows stably with almost no change in flow velocity and pressure, and flows into the Ps port 11 (see FIG. 3).

[0052] Furthermore, the downstream pressure of the CS valve 50, i.e., the pressure of the fluid in the valve chamber 20, is easily affected by the discharge pressure Pd that is constantly supplied via a fixed orifice 9 (see Figure 1) to adjust the control pressure Pc in the control chamber of the variable displacement compressor, and therefore the pressure is less likely to drop than in the Ps port 11.

[0053] In the first embodiment, as described above, by passing through the reduction region with a supersonic flow of the fluid, in addition to the effect of the discharge pressure Pd, the downstream pressure of the CS valve 50 can be increased, so that the pressure of the fluid in the space S (see FIG. 1) inside the casing 81, which changes based on the pressure difference with the pressure of the fluid in the valve chamber 20, i.e., the force of the back pressure acting on the CS valve body 51, can be further increased. In addition, by passing through the reduction region with a subsonic flow of the fluid, the downstream pressure of the CS valve 50 can be reduced, so that the effect of the discharge pressure Pd on the pressure of the fluid in the space S inside the casing 81, which changes based on the pressure difference with the pressure of the fluid in the valve chamber 20, i.e., the force of the back pressure acting on the CS valve body 51, can be suppressed.

[0054] As described above, in the capacity control valve V1 of the first embodiment, the flow path downstream of the CS valve 50 is provided with a flow path C1 as a decreasing region in which the flow path cross-sectional area tends to decrease (dA<0) toward the downstream side. When the fluid passing through the CS valve 50 is a supersonic flow (M>1), the flow velocity of the fluid passing through the flow path C1 decreases, the pressure increases, and a force in the valve closing direction acts on the CS valve body 51. In addition, the force of the back pressure acting on the CS valve body 51, which is influenced by the discharge pressure Pd, can be further increased. As shown in FIG. 4(a), the valve closing characteristic of the CS valve 50 is improved, and the CS valve 50 can be closed with a small current value. Note that in the reference diagram of FIG. 4(b) showing the characteristics of a flow path with a constant flow path cross-sectional area (dA=constant), the valve cannot be closed when the discharge pressure Pd is high, in other words, a large current is required to close the valve.

[0055] Furthermore, when the fluid passing through the CS valve 50 is a subsonic flow (M<1), the flow velocity of the fluid passing through the flow path C1 increases, the pressure decreases, and a force acts on the CS valve body 51 in the valve opening direction. As a result, as shown in FIG. 5(a), the influence of the pressure of the fluid upstream of the CS valve 50 on the downstream pressure of the CS valve 50, which is the discharge pressure Pd in ​​this embodiment, can be suppressed. Note that in the reference diagram of FIG. 5(b) showing the characteristics of a flow path with a constant flow path cross-sectional area (dA=constant), the variation in the drive current is large. In this way, the influence of the discharge pressure Pd on the force due to the back pressure acting on the CS valve body 51 can be suppressed, and the variation in the stroke of the CS valve body 51 relative to the current value input to the solenoid 80 can be suppressed, and the opening of the CS valve 50 can be accurately adjusted.

[0056] In this way, a flow path C1 is provided in the flow path downstream of the CS valve 50, which is a decreasing region in which the flow path cross-sectional area tends to decrease (dA<0) as it progresses downstream, and the controllability of the CS valve 50 can be improved by appropriately controlling the downstream pressure of the CS valve 50 in accordance with the flow velocity of the fluid passing through the CS valve 50.

[0057] In addition, the flow path C1 as a decreasing region has a flow path cross-sectional area that continuously decreases toward the downstream side, thereby stabilizing the flow of the fluid and eliminating stagnation. Also, the flow velocity and pressure of the fluid passing through the flow path C1 can be changed at an accelerated rate.

[0058] In addition, the CS valve 50 is composed of a CS valve seat 40a having an inclined cross-sectional shape and a contact portion 51a of the CS valve body 51 having a curved cross-sectional shape, and a flow path C1 is formed as a reduction region between the tapered surface constituting the CS valve seat 40a and the abutment portion 51a of the CS valve body 51, so that when the CS valve body 51 is in the closed position or throttling position, the flow of fluid passing through the CS valve 50 can be stabilized in the tangential direction (see solid arrow in Figure 3).

[0059] In addition, the CS valve seat 40a is composed of a tapered surface with a linear cross-sectional inclined surface extending circumferentially, and stabilizes the flow of fluid passing through the CS valve 50, more specifically the flow of fluid in flow path C1, in the tangential direction when the CS valve body 51 is in the closed position or throttling position, and can guide the fluid flow along the inclined surface, thereby stabilizing the fluid flow all the way to the flow path C2 that continues downstream.

[0060] In addition, it is preferable that the tapered surface constituting the CS valve seat 40a is located downstream along the normal to the abutment portion 51a of the CS valve body 51. This causes the fluid that has passed through the reduction region to proceed in a straight line, making it difficult to impede the flow velocity of the fluid, which is close to the speed of sound.

[0061] In addition, in flow passage C2, the flow passage cross-sectional area is constant up to the opening of the Ps port 11 on the valve chamber 20 side, and the flow of the fluid can be stabilized with almost no change in the flow velocity and pressure of the passing fluid, so that the pressure of the fluid in the valve chamber 20 is easily stabilized.

[0062] In addition, the flow path C1 can form a reduced area by utilizing the tapered surface constituting the CS valve seat 40a in the CS valve 50 serving as a poppet valve and the abutment portion 51a of the CS valve body 51, thereby simplifying the structure of the displacement control valve V1.

[0063] Furthermore, since the CS valve seat 40a is formed on the valve seat member 40 which is separate from the valve housing 10, the machining precision of the tapered surface for forming the reduced area can be improved.

[0064] In this embodiment 1, the flow path C2 continuing downstream from the flow path C1 has been described as having a constant flow path cross-sectional area due to the inner circumferential surface 10e of the valve housing 10 and the outer circumferential surface 51d of the CS valve body 51 being arranged in parallel. However, the present invention is not limited to this. The shape of the inner circumferential surface 10e of the valve housing 10 or the outer circumferential surface 51d of the CS valve body 51 may be changed so as to continuously form a decreasing region in which the flow path cross-sectional area tends to decrease (dA<0) downstream in the flow path C2. EXAMPLES

[0065] A displacement control valve according to a second embodiment will be described with reference to Fig. 6 to Fig. 8. Note that a description of the same configuration as in the first embodiment will be omitted.

[0066] As shown in FIG. 6, in the displacement control valve V2 of the second embodiment, a valve housing 110 is formed with a Ps port 111 as an outflow port that penetrates radially and communicates with the suction chamber of the variable displacement compressor.

[0067] Furthermore, a recess 110a is formed on the axial left side of the valve housing 110. A cylindrical valve seat member 40 is press-fitted into the recess 110a from the axial left. By press-fitting and fixing a valve seat member 140 into the recess 110a, a Pc port is formed as an inlet port that communicates with the control chamber of the variable displacement compressor via a through-hole 140b that passes through the valve seat member 140 in the axial direction.

[0068] A valve chamber 120 is formed inside the valve housing 110, and the contact portion 51a of the CS valve element 51 is disposed in the valve chamber 120 so as to be able to reciprocate in the axial direction. The Ps port 111 extends radially inward from the outer circumferential surface of the valve housing 110 and communicates with the valve chamber 120. The valve chamber 120 is formed with a tapered surface 110e that is connected to the axial left end of the opening of the Ps port 111 on the valve chamber 120 side and gradually increases in diameter toward the axial left (see FIG. 7).

[0069] As shown in FIG. 7, the recess 110a of the valve housing 110 is formed so that its inner diameter R11 is larger than the inner diameter R12 at the axial left end of the tapered surface 110e that constitutes the valve chamber 120 (R11>R12), so that the bottom surface of the recess 110a forms a receiving portion 110b that can abut against the flat surface 140c on the axial right side of the valve seat member 140.

[0070] As shown in Fig. 7, the valve seat member 140 is cylindrical with a through hole 140b penetrating in the axial direction. At the right end of the valve seat member 140 in the axial direction, from the outer diameter side to the inner diameter side, there is formed an annular flat surface 140c and a CS valve seat 140a as a valve seat having a cross-sectional inclined shape that is connected to the flat surface 140c from the inner diameter side and gradually reduces in diameter toward the left in the axial direction. That is, the CS valve seat 140a is formed on the edge of the through hole 140b as a through flow passage, and is constituted by a tapered surface in which a cross-sectional linear inclined surface extends in the circumferential direction.

[0071] Furthermore, by abutting the flat surface 140c on the axial right side of the valve seat member 140 in axial contact with the receiving portion 110b formed by the bottom surface of the recess 110a (see FIG. 8), it is possible to regulate the degree of insertion of the valve seat member 140 into the recess 110a and to improve the sealing performance between the valve housing 110 and the valve seat member 140. At this time, the outer diameter end of the tapered surface constituting the CS valve seat 40a is arranged to be continuous with the axial left end of the tapered surface 110e in the valve chamber 120 of the valve housing 110.

[0072] As a result, a flow path on the downstream side of the CS valve 50 extending to the opening on the valve chamber 120 side of the Ps port 111 is formed by a flow path C101 formed between the tapered surface constituting the CS valve seat 140a of the valve seat member 140 and the abutting portion 51a of the CS valve body 51, and a flow path C102 formed between the tapered surface constituting the CS valve seat 140a of the valve seat member 140, the outer circumferential surface 51d of the large diameter portion 51b of the CS valve body 51, and the tapered surface 110e of the valve housing 110 and the outer circumferential surface 51d of the large diameter portion 51b of the CS valve body 51 (see FIG. 8). Note that FIG. 8 shows a state in which the CS valve body 51 has been stroked to a throttling position near the closed position during normal control of the displacement control valve V2.

[0073] In the second embodiment, the flow passage C101 has a flow passage cross-sectional area A101 between the inner diameter end of the tapered surface constituting the CS valve seat 140a and the abutment portion 51a of the CS valve body 51, and a flow passage cross-sectional area A102 between the tapered surface constituting the CS valve seat 140a and the outer diameter end of the abutment portion 51a of the CS valve body 51, which is substantially the same (A101=A102), and the flow passage cross-sectional area is substantially constant. Also, the flow passage C102 has a flow passage cross-sectional area A104 on the downstream side smaller than a flow passage cross-sectional area A103 on the upstream side between the tapered surface 110e of the valve housing 110 and the abutment portion 51a of the CS valve body 51 (A103>A104), and constitutes a decreasing region in which the flow passage cross-sectional area tends to decrease (dA<0) toward the downstream side.

[0074] The flow passage cross-sectional area of ​​the flow passage C102 continuously decreases downstream, and in the decreasing region, the flow passage cross-sectional area A104, ie, the minimum flow passage cross-sectional area, is constant regardless of the stroke of the CS valve body 51.

[0075] According to this, in the displacement control valve V2 of the second embodiment, the flow path downstream of the CS valve 50 is provided with a flow path C102 as a decreasing region in which the flow path cross-sectional area tends to decrease (dA>0) toward the downstream side. When the fluid passing through the CS valve 50 is a supersonic flow (M>1), the flow velocity of the fluid passing through the flow path C102 decreases, the pressure increases, and a force in the valve closing direction acts on the CS valve body 51. In addition, the force of the back pressure acting on the CS valve body 51, which is influenced by the discharge pressure Pd, can be further increased. This improves the valve closing characteristic of the CS valve 50, and the CS valve 50 can be closed with a small current value.

[0076] Furthermore, when the fluid passing through the CS valve 50 is a subsonic flow (M<1), the flow velocity of the fluid passing through the flow path C102 increases and the pressure decreases, and a force in the valve opening direction acts on the CS valve element 51. This makes it possible to suppress the effect of the discharge pressure Pd on the downstream pressure of the CS valve 50. In this way, the effect of the discharge pressure Pd on the force due to the back pressure acting on the CS valve element 51 can be suppressed, and the variation in the stroke of the CS valve element 51 relative to the current value input to the solenoid 80 can be suppressed, making it possible to precisely adjust the opening of the CS valve 50.

[0077] In this way, a flow path C102, which is a decreasing region in which the flow path cross-sectional area tends to decrease (dA<0) downstream, is provided in the flow path downstream of the CS valve 50, and the controllability of the CS valve 50 can be improved by appropriately controlling the downstream pressure of the CS valve 50 in accordance with the flow velocity of the fluid passing through the CS valve 50.

[0078] Furthermore, since the flow passage C102 as the reduction region has a constant minimum flow passage cross-sectional area regardless of the stroke of the CS valve body 51, the pressure of the fluid in the valve chamber 120 after passing through the reduction region can always be stabilized.

[0079] Furthermore, the tapered surface 110e of the valve housing 110 that constitutes the flow path C102 is configured as a tapered surface that extends linearly to connect to the axial left end of the opening of the Ps port 111 on the valve chamber 120 side, making it easier to guide the fluid into the Ps port 111 while acceleratingly changing the flow rate and pressure. This makes it possible to stabilize the flow of fluid in the flow path downstream of the CS valve 50 and eliminate stagnation, thereby making it possible to further stabilize the downstream pressure of the CS valve 50, i.e., the pressure of the fluid in the valve chamber 120.

[0080] In addition, since a flow path C101 with a constant flow path cross-sectional area is formed between the tapered surface constituting the CS valve seat 40a of the CS valve 50 and the abutment portion 51a of the CS valve body 51, the flow can be stabilized in the tangential direction (see solid arrow in Figure 8) without substantially changing the flow velocity and pressure of the fluid passing through the CS valve 50 when the CS valve body 51 is in the closed position or throttling position.

[0081] In addition, since the tapered surface that constitutes the CS valve seat 40a is continuous with the tapered surface 110e of the valve housing 110 that constitutes the flow path C102, which is the reduction region, it is easy to make the flow path cross-sectional area large at the continuous portion of the flow paths C101, C102, i.e., the upstream side of the flow path C102, which is the reduction region.

[0082] In addition, the CS valve seat 140a is formed on the valve seat member 140 which is separate from the valve housing 110, and the tapered surface 110e which constitutes the reduction region is formed on the valve housing 110. Therefore, it is easy to set the flow path cross-sectional area in the flow paths C101, C102, and the reduction region can be easily formed.

[0083] In this embodiment 2, a configuration has been described in which the flow path C101 formed upstream of the flow path C102, which is the reduction region, has a constant flow path cross-sectional area, but this is not limited to the above, and the flow path cross-sectional area of ​​the flow path C101 may have a tendency to increase toward the downstream side.

[0084] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0085] For example, in the above embodiment, the valve housing and the valve seat member are described as being made of a metal material, but this is not limiting, and the valve seat member may be made of a resin material or the like as long as it is harder than the hardness of the inside of the flow passage of the valve housing. Also, in this case, it is preferable that the valve seat member is made of a material different from that of the valve body.

[0086] Furthermore, the CS valve body does not need to have a cross-sectional curved shape at the contact portion with the CS valve seat.

[0087] Furthermore, the tapered surface that constitutes the CS valve seat is not limited to being linear, but may be arcuate.

[0088] Furthermore, the decreasing region is not limited to a region in which the flow passage cross-sectional area decreases continuously due to a tapered surface, but may be a region in which the flow passage cross-sectional area decreases in stages due to a stepped surface.

[0089] Further, the displacement control valve in the above embodiment has been described using a CS valve as a poppet valve as an example, but the poppet valve may be a DC valve that opens and closes the flow path between the Pd port as the inlet port and the Pc port as the outlet port. [Explanation of symbols]

[0090] 9 Fixed Orifice 10 Valve housing 10a Recess 10b Receiving part 10c Guide hole 10d Recess 10e Inner surface 11 Ps port (outlet port) 20 Valve chamber 21 Through hole 30 Pressure Operated Valve 40 Valve seat member 40a CS valve seat (valve seat) 40b through hole (through flow passage, inlet port) 40c flat surface 50 CS valve (poppet valve) 51 CS valve body (valve body) 51a Contact part 51d Outer surface 80 Solenoid (drive source) 110 Valve housing 110e Tapered surface 111 Ps port (outlet port) 120 Valve chamber 140 Valve seat material 140a CS valve seat (valve seat) 140b through hole (through flow passage, inlet port) 140c flat surface C1, C102 flow path (reduced area, downstream flow path) C2, C101 flow path (downstream flow path) S space V1, V2 Capacity control valve (valve)

Claims

1. a valve housing having an inlet port and an outlet port formed therein; A valve body driven by a drive source; a spring that biases the valve body in a direction opposite to a drive direction of the drive source; A poppet valve including a valve seat formed on an edge of a through-flow passage and the valve body, the poppet valve controlling a flow rate by movement of the valve body, A flow passage on the downstream side of the poppet valve is provided with a decreasing region in which the flow passage cross-sectional area tends to decrease toward the downstream side, The poppet valve is configured with the valve seat having a cross-sectional inclined shape and the valve body having a contact portion having a cross-sectional curved shape that contacts the valve seat, an outer circumferential surface of the valve body and an inner circumferential surface of the valve housing have a pair of parallel surfaces that are parallel to each other and extend in a drive direction of the valve body, The reduction region includes a first reduction region in which the flow path cross-sectional area decreases downstream, and a second reduction region downstream of the first reduction region in which the minimum flow path cross-sectional area is maintained constant by the pair of parallel surfaces regardless of the stroke of the valve body.

2. 2. The valve of claim 1, wherein the first decreasing region has a flow passage cross-sectional area that decreases continuously.

3. The valve of claim 1 , wherein the cross-sectional tapered shape is linear.

4. 4. The valve according to claim 1, wherein the inclined surface constituting the valve seat is continuous with the inclined surface constituting the first decrease region.

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