valve

Abstract

Provided is a valve capable of reducing leakage of a working fluid between a back space and one space.　A gap S10 connecting one space S2 and a back space S3 is formed between a rod 20 and a valve housing 10, and the gap S10 has a bent portion E.

Description

[Technical Field]

[0001] The present invention relates to a valve for controlling a working fluid. [Background technology]

[0002] Valves used to control working fluids in various industrial fields have a valve seat and a valve body that can be attached to and detached from the valve seat, and the pressure and flow rate of the working fluid can be controlled by adjusting the valve opening.

[0003] Typical valve configurations include spool valves, in which a spool (valve element) moves parallel to the opening (valve seat), butterfly valves, in which the valve element has a pivot axis, and lift valves, in which the valve element moves perpendicular to the opening (valve seat). Of these valves, the lift valve is the most suitable for flow rate and pressure control.

[0004] An example of a lift valve is a displacement control valve for a variable displacement compressor used in an air conditioning system for an automobile, etc. A variable displacement compressor includes a rotating shaft driven by an engine, a swash plate connected to the rotating shaft with a variable inclination angle, and compression pistons connected to the swash plate. The inclination angle of the swash plate is changed to vary the stroke of the pistons and control the amount of fluid discharged. The inclination angle of the swash plate can be continuously varied by appropriately controlling the pressure in the control chamber, using a displacement control valve driven to open and close by electromagnetic force, while utilizing the suction pressure Ps in the suction chamber that draws in the fluid, the discharge pressure Pd in ​​the discharge chamber that discharges the fluid pressurized by the piston, and the control pressure Pc in the control chamber that houses the swash plate.

[0005] The capacity control valve of Patent Document 1 comprises a valve housing in which a primary pressure space through which a control fluid of control pressure Pc passes and a secondary pressure space through which a control fluid of suction pressure Ps passes, a valve seat provided between the primary pressure space and the secondary pressure space, and a valve body whose valve contact portion is provided in the primary pressure space and whose rod portion is provided in the back space on the solenoid side and which can be moved toward and away from the valve seat, and the control pressure Pc in the control chamber is adjusted by moving the valve body using electromagnetic force generated by the solenoid.

[0006] The valve housing is also formed with a communication passage that connects the secondary pressure space with the back space. This allows the secondary pressure space and the back space to be at the same pressure through the communication passage, eliminating pressure differences on both axial sides of the valve disc and enabling precise rod control according to the current applied to the solenoid. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] WO 2020 / 110925 (page 10, Figure 3) Summary of the Invention [Problem to be solved by the invention]

[0008] In the displacement control valve of Patent Document 1, the rod portion of the valve disc is inserted into a guide hole provided between the primary pressure space and the back space in the valve housing, and the rod portion is guided by the guide hole to slide stably. However, because there is a minute gap between the outer peripheral surface of the rod portion and the inner peripheral surface of the guide hole, there is a risk that the fluid in the primary pressure space at the control pressure Pc will leak slightly between the outer peripheral surface of the rod portion and the inner peripheral surface of the guide hole into the back space, making it difficult to control the control pressure Pc in the primary pressure space with high accuracy.

[0009] The present invention has been made in view of these problems, and has as its object to provide a valve that can reduce leakage of working fluid between the back space and one of the spaces. [Means for solving the problem]

[0010] In order to solve the above problems, the valve of the present invention comprises: a valve housing having a primary pressure space, a secondary pressure space, and a back space adjacent to one of the primary pressure space and the secondary pressure space; a valve seat disposed between the primary pressure space and the secondary pressure space; a rod that is inserted into a guide hole of the valve housing that is provided between the one space and the back space and that is driven in the axial direction by a drive source; a valve body that is seated on or separated from the valve seat by driving the rod; A valve including a communication means for communicating the back space with the other of the primary pressure space and the secondary pressure space, A gap is formed between the rod and the valve housing, connecting the one space and the back space, and the gap has a bent portion. This causes a pressure loss in the working fluid when the direction of the working fluid flowing through the gap formed between the rod and the valve housing changes at the bent portion, thereby reducing leakage of the working fluid from the back space to one of the spaces or from one space to the back space.

[0011] When the valve is closed, the flow path cross-sectional area of ​​the bent portion may be smallest. According to this, the flow path cross-sectional area of ​​the bent portion changes depending on the valve opening degree, and the flow path cross-sectional area is smallest when the valve is closed, so the pressure loss of the working fluid that occurs in the bent portion when the valve is closed can be increased.

[0012] When the valve is closed, a pair of axially opposing surfaces that constitute the bent portion and are opposed to each other in the axial direction may be spaced apart from each other in the axial direction. With this, when the valve is closed, the pair of axially opposing surfaces of the rod and the valve housing do not come into contact with each other, so that the valve disc can be reliably seated on the valve seat.

[0013] The side surface of the rod and the side surface of the valve housing may be the pair of axially opposing surfaces. According to this, a bent portion is formed at the inlet or outlet of the gap, so that the outflow or inflow of the working fluid into the gap can be effectively inhibited.

[0014] The pair of axially opposing surfaces may be perpendicular to the axial direction. This allows the pressure loss of the working fluid occurring at the bent portion to be increased, and also ensures that the pair of radially opposed surfaces that are continuous with the pair of axially opposed surfaces are long in the axial direction.

[0015] The bent portion may be crank-shaped. With this, the direction of the flow of the working fluid changes on both sides in the radial direction between the pair of axially opposed surfaces, so that the pressure loss of the working fluid can be increased.

[0016] The effective pressure-receiving area of ​​the rod may be equal to the effective pressure-receiving area of ​​the valve. This cancels out the force due to the fluid pressure in the back space acting on the rod and the force due to the fluid pressure in the other space acting on the valve body, so the valve body can be moved with precision regardless of the fluid pressure in the back space and the other space. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view showing a displacement control valve according to a first embodiment of the present invention. [Figure 2] FIG. 4 is an enlarged cross-sectional view of a main part showing a gap between a guide hole and a rod when the valve is closed. [Figure 3] FIG. 2 is a schematic diagram showing a working fluid flowing through a gap. [Figure 4] FIG. 4 is an enlarged cross-sectional view of a main part showing a state in which the capacity control valve is closed. [Figure 5] FIG. 4 is an enlarged cross-sectional view of a main part showing a state in which the capacity control valve is opened. [Figure 6] FIG. 2 is an enlarged cross-sectional view of a main portion showing a first modified example of the displacement control valve of the first embodiment. [Figure 7] FIG. 4 is a cross-sectional view showing a second modification of the displacement control valve of the first embodiment. [Figure 8] FIG. 6 is an enlarged cross-sectional view of a main portion of a capacity control valve according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A valve according to the present invention will be described below with reference to the following examples. Although the embodiments will be described using a displacement control valve as an example, the present invention is also applicable to other uses. [Example]

[0019] A displacement control valve according to a first embodiment will be described with reference to Figures 1 to 5. In the following description, the left and right sides as viewed from the front of Figure 1 will be referred to as the left and right sides of the displacement control valve. Specifically, the left side of the drawing where the valve housing 10 is located 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 located will be referred to as the right side of the displacement control valve.

[0020] The capacity control valve of the present invention is incorporated into a variable displacement compressor (not shown) used in the air conditioning system of an automobile, etc., and variably controls the pressure of the working fluid (hereinafter simply referred to as "fluid"), which is a refrigerant. This adjusts the discharge rate of the variable displacement compressor, and the air conditioning system is adjusted to achieve a target cooling capacity.

[0021] First, we will explain the variable displacement compressor. 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. This communication passage is provided with a fixed orifice 9 for balancing the pressures in the discharge chamber and the control chamber (see Figure 1).

[0022] The variable displacement compressor includes a rotating shaft driven by an engine (not shown) installed outside the casing, a swash plate tiltably connected to the rotating shaft via a hinge mechanism within a control chamber, and multiple pistons connected to the swash plate and fitted reciprocally within their respective cylinders. The pressure within the control chamber is appropriately controlled by a displacement control valve V1, which is electromagnetically driven to open and close, using the suction pressure Ps in the suction chamber that draws in fluid, the discharge pressure Pd in ​​the discharge chamber that discharges fluid pressurized by the pistons, and the control pressure Pc in the control chamber that houses the swash plate. As a result, the stroke of the pistons changes as the tilt angle of the swash plate changes, thereby changing the discharge volume of the variable displacement compressor.

[0023] 1, in a capacity control valve V1 of this embodiment 1 incorporated in a variable displacement compressor, a valve 50 in the capacity control valve V1 opens and closes in response to current flowing through a coil 86 constituting a solenoid 80 serving as a drive source. By controlling the opening and closing of the valve 50, the flow rate from the control chamber to the suction chamber changes, thereby variably controlling the control pressure Pc in the control chamber. Note that discharge fluid at a discharge pressure Pd in ​​the discharge chamber is constantly supplied to the control chamber via a fixed orifice 9, and closing the valve 50 in the capacity control valve V1 increases the control pressure Pc in the control chamber.

[0024] 1, in the capacity control valve V1 of the first embodiment, the valve 50 is composed of a contact portion 54 serving as a valve element and a valve seat 40a. The contact portion 54 is provided on the valve portion 51 of the movable body 56. The valve seat 40a is provided on a cylindrical valve seat member 40. The valve seat member 40 is press-fitted and fixed into the communication hole portion 10b of the valve housing 10.

[0025] A tapered contact portion 54 is formed on the axial right side of the valve portion 51. The valve 50 opens and closes when the contact portion 54 moves axially toward and away from the valve seat 40a.

[0026] Next, the structure of the displacement control valve V1 will be described. The displacement control valve V1 is mainly composed of a valve housing 10 and a valve seat member 40 made of a metal material, a solenoid 80 as a drive source, and a movable body 56.

[0027] 1 and 2, the movable body 56 is composed of a rod portion 20 as a rod element and a valve portion 51 as a valve element. The rod portion 20 extends in the axial direction. The valve portion 51 is formed at the left end of the rod portion 20 in the axial direction.

[0028] The valve portion 51 includes a large diameter portion 53 and an abutment portion 54. The large diameter portion 53 has a larger diameter than the rod portion 20. The abutment portion 54 has a tapered shape that gradually reduces in diameter from the large diameter portion 53 toward the rod portion 20 on the right side in the axial direction.

[0029] The valve portion 51 is disposed axially to the left of the valve seat member 40. The rod portion 20 is inserted through the valve seat member 40 and extends axially to the right.

[0030] The rod portion 20 is formed with a first small diameter portion 21, a large diameter portion 22, and a second small diameter portion 23 in this order from the left in the axial direction.

[0031] The second small diameter portion 23 has a diameter slightly larger than that of the first small diameter portion 21. The large diameter portion 22 has a diameter larger than that of the second small diameter portion 23. The first small diameter portion 21 and the second small diameter portion 23 may have the same diameter, or the first small diameter portion 21 may have a diameter larger than that of the second small diameter portion 23.

[0032] The large diameter portion 22 is inserted into a guide hole 10e (described later) provided in the valve housing 10. The specific structure of the large diameter portion 22 will be described in detail later.

[0033] A primary pressure space S1 is formed on the axial left side of the valve housing 10, and the primary pressure space S1 communicates with the control chamber through an inlet port 11 that opens on the axial left side. A secondary pressure space S2 is formed on the axial right side of the primary pressure space S1 in the valve housing 10, and the secondary pressure space S2 communicates with the discharge chamber through an outlet port 12 that penetrates radially.

[0034] The valve housing 10 is formed with a recess 10a that is recessed axially rightward from its left end and is open at its left end. The opening at the left axial end of the recess 10a serves as an inlet port 11. The left axial end of the valve housing 10 is closed by a component that forms a control chamber (not shown). The space surrounded by this component and the recess 10a serves as a primary pressure space S1.

[0035] The valve housing 10 also has a recess 10c formed on the inner diameter side of the right axial end, recessed axially leftward. A guide hole 10e and a communication hole 10b are formed between the recess 10a and the recess 10c, and communicate with each other in the axial direction. The communication hole 10b has a smaller diameter than the recesses 10a and 10c. The guide hole 10e has a smaller diameter than the communication hole 10b. The space surrounded by the communication hole 10b forms the secondary pressure space S2.

[0036] The valve housing 10 also has an annular inner land 10f (see FIG. 2) extending radially inward between the communication hole 10b and the recess 10c. The guide hole 10e is provided in the surface of the inner land 10f and extends axially.

[0037] The valve seat member 40 includes a cylindrical portion 41 and an annular protrusion 42 (see FIGS. 4 and 5). The cylindrical portion 41 extends cylindrically in the axial direction. The annular protrusion 42 protrudes radially outward from the left axial end of the cylindrical portion 41. The inner diameter of the cylindrical portion 41 is larger than the first small diameter portion 21 of the rod portion 20.

[0038] The valve seat member 40 is press-fitted from the left in the axial direction into a communicating hole 10b that penetrates the bottom of the recess 10a, and is thereby hermetically fixed to the valve housing 10. Furthermore, the annular protrusion 42 abuts against the bottom end surface 10d of the recess 10a (see FIGS. 4 and 5), preventing excessive insertion of the valve seat member 40 into the communicating hole 10b and positioning the valve seat member 40 in the axial direction.

[0039] A valve seat 40a is formed on the inner diameter side of the left axial end of the valve seat member 40. The valve seat 40a has a tapered shape that gradually reduces in diameter toward the right axial direction.

[0040] The flange portion 82d of the center post 82 is fitted and fixed from the axial right into the recess 10c of the valve housing 10. Furthermore, the casing 81 is fitted and fixed from the axial right onto the flange portion 82d, thereby integrally connecting the valve housing 10, center post 82, and casing 81.

[0041] A through hole 13 is formed in the valve housing 10 as a communication means extending in the axial direction. The through hole 13 opens to the bottom surfaces of the recesses 10a and 10c at both axial ends, i.e., it communicates with the primary pressure space S1 and the back space S3 within the solenoid 80. The through hole 13 is formed with a constant cross section.

[0042] As shown in FIG. 1, the solenoid 80 is mainly composed of a casing 81, a center post 82, a rod portion 20, a movable core 84, a coil spring 85, a coil 86, and a sleeve 87.

[0043] The casing 81 has a recess 81b and a through-hole 81a. The recess 81b is recessed from the left side to the right side in the axial direction of the casing 81. The through-hole 81a is formed to extend from the bottom of the recess 81b to the right side in the axial direction.

[0044] The center post 82 has a generally cylindrical shape and is made of a rigid body, such as iron or silicon steel, which is a magnetic material. Specifically, the center post 82 includes a cylindrical portion 82b extending in the axial direction and an annular flange portion 82d. The cylindrical portion 82b has an insertion hole 82c. The rod portion 20 is inserted through the insertion hole 82c so as to be able to reciprocate axially. The flange portion 82d extends radially outward from the outer peripheral surface of the left axial end of the cylindrical portion 82b.

[0045] The cylindrical portion 82b is inserted from the axial left into the through-hole 81a of the casing 81. The center post 82 is positioned relative to the valve housing 10 and the casing 81 by having the flange portion 82d sandwiched axially between the bottom of the recess 10c of the valve housing 10 and the bottom of the recess 81b of the casing 81.

[0046] The right end of the rod portion 20 in the axial direction is inserted and fixed into the movable iron core 84 .

[0047] Coil spring 85 is a compression spring, and is disposed between center post 82 and movable iron core 84. The left axial end of coil spring 85 is fitted into recess 82e formed in the right axial end of cylindrical portion 82b of center post 82. In other words, coil spring 85 biases movable iron core 84 axially rightward, which is the direction in which valve 50 closes.

[0048] The coil 86 is an excitation coil wound around the outside of the center post 82 via a bobbin.

[0049] The sleeve 87 has a cylindrical shape with a bottom. Part of the center post 82, the movable iron core 84, the coil spring 85, and part of the rod portion 20 are housed in the sleeve 87.

[0050] The back space S3 within the solenoid 80 is the space mainly within the sleeve 87 on the back side of the valve portion 51, separated from the secondary pressure space S2. More specifically, it includes the space between the recess 10c and the left end of the center post 82, the space within the center post 82, and the spaces on the left and right sides of the movable iron core 84 within the sleeve 87.

[0051] Next, the structures of the large diameter portion 22 of the rod portion 20 and the guide hole 10e of the valve housing 10 will be described with reference to FIGS.

[0052] 2 and 3, large diameter portion 22 is formed with, from the right in the axial direction, a first portion 24, a second portion 25, and a third portion 26. First portion 24 and second portion 25 are disposed within guide hole 10e. Third portion 26 is disposed axially to the left of guide hole 10e, i.e., within secondary pressure space S2.

[0053] The first portion 24 has a smaller diameter than the second portion 25. The second portion 25 has a smaller diameter than the third portion 26. That is, the large diameter portion 22 increases in diameter in a stepped manner from the axial right side to the axial left side.

[0054] The outer peripheral surface 24a of the first portion 24, the outer peripheral surface 25a of the second portion 25, and the outer peripheral surface 26a of the third portion 26 are axial portions that extend parallel to each other in the axial direction. The right end surface 25b of the second portion 25 and the right end surface 26b of the third portion 26 are radial portions that extend radially.

[0055] Specifically, the right end face 25b of the second portion 25 extends radially, perpendicular to the outer peripheral surface 24a of the first portion 24 and the outer peripheral surface 25a of the second portion 25. The right end face 26b of the third portion 26 extends radially, perpendicular to the outer peripheral surface 25a of the second portion 25 and the outer peripheral surface 26a of the third portion 26.

[0056] Between the outer peripheral surface 26a of the third portion 26 and the first small diameter portion 21 of the rod portion 20, a tapered surface portion 27 (see FIG. 2) is formed, the diameter of which decreases toward the left in the axial direction.

[0057] The valve housing 10 is formed with a first portion 14, a second portion 15, and a third portion 16 in this order from the right in the axial direction, and these portions 14, 15, and 16 define a guide hole 10e.

[0058] The inner peripheral surface 14a of the first portion 14 extends from the right surface of the inner land 10f parallel to the outer peripheral surface 24a of the first portion 24 of the large diameter portion 22, and then extends at an incline so as to reduce in diameter toward the left in the axial direction.

[0059] An inner peripheral surface 15a of the second portion 15 extends from the left axial end of the inner peripheral surface 14a in parallel with an outer peripheral surface 24a of the first portion 24 of the large diameter portion 22. A left end face 15b of the second portion 15 extends perpendicular to the outer diameter direction from the left axial end of the inner peripheral surface 15a.

[0060] Specifically, the left end surface 15b extends parallel to the right end surface 25b of the second portion 25. That is, the right end surface 25b and the left end surface 15b form a pair of axially opposed surfaces that face each other in the axial direction. Also, the inner peripheral surface 15a and the outer peripheral surface 24a form a pair of radially opposed surfaces that face each other in the radial direction.

[0061] The inner circumferential surface 16a of the third portion 16 extends from the outer diameter end of the left end face 15b toward the left side in the axial direction in parallel with the outer circumferential surface 25a of the second portion 25 of the large diameter portion 22. The left end face 16b of the third portion 16 extends perpendicular to the outer diameter direction from the left end of the inner circumferential surface 16a. In other words, the left end face 16b is the left end side surface of the inner land 10f.

[0062] The left end surface 16b extends parallel to the right end surface 26b of the third portion 26. That is, the right end surface 26b and the left end surface 16b form a pair of axially opposed surfaces that face each other in the axial direction. The inner peripheral surface 16a and the outer peripheral surface 25a form a pair of radially opposed surfaces that face each other in the radial direction.

[0063] A gap S10 is formed between the first portion 24, the second portion 25, and the third portion 26 of the large diameter portion 22 of the rod portion 20 and the first portion 14, the second portion 15, and the third portion 16 of the valve housing 10, connecting the secondary pressure space S2 and the back space S3.

[0064] In the following, in the gap S10, the area between the outer peripheral surface 24a of the first portion 24 and the inner peripheral surface 14a of the first portion 14 will be referred to as the first gap S11, the area between the outer peripheral surface 24a of the first portion 24 and the inner peripheral surface 15a of the second portion 15 will be referred to as the second gap S12, the area between the right end face 25b of the second portion 25 and the left end face 15b of the second portion 15 will be referred to as the third gap S13, the area between the outer peripheral surface 25a of the second portion 25 and the inner peripheral surface 16a of the third portion 16 will be referred to as the fourth gap S14, and the area between the right end face 26b of the third portion 26 and the left end face 16b of the third portion 16 will be referred to as the fifth gap S15.

[0065] A plurality of substantially L-shaped bent portions E are formed in the gap S10. More specifically, the second gap S12 and the third gap S13 form a bent portion E1. The third gap S13 and the fourth gap S14 form a bent portion E2. The fourth gap S14 and the fifth gap S15 form a bent portion E3.

[0066] The second gap S12, the third gap S13, and the fourth gap S14 in the gap S10, i.e., the bent portion E1 and the bent portion E2, form a crank shape. In other words, the second gap S12 extends from the inner diameter side of the third gap S13 to the right in the axial direction, and the fourth gap S14 extends from the outer diameter side of the third gap S13 to the left in the axial direction.

[0067] Furthermore, the radial distance Δ12 between the outer peripheral surface 24a and the inner peripheral surface 15a in the second gap S12 and the radial distance Δ14 between the outer peripheral surface 25a and the inner peripheral surface 16a in the fourth gap S14 are substantially the same length (Δ12 = Δ14). Note that the radial distance Δ12 of the second gap S12 and the radial distance Δ14 of the fourth gap S14 may be different.

[0068] The second gap S12 and the fourth gap S14 are minute gaps. The inner circumferential surface 15a of the second portion 15 and the inner circumferential surface 16a of the third portion 16 of the valve housing 10 serve as guide portions that guide the outer circumferential surface 24a of the first portion 24 and the outer circumferential surface 25a of the second portion 25 of the rod portion 20 in sliding relation.

[0069] Next, the opening and closing operation of the displacement control valve V1 will be described.

[0070] 1 and 4, in the non-energized state of the capacity control valve V1, the movable iron core 84 is pressed axially rightward, i.e., in the valve closing direction, by the biasing force of the coil spring 85, so that the abutment portion 54 of the valve portion 51 is seated on the valve seat 40a, and the valve 50 is closed.

[0071] Specifically, the valve seat 40a is tapered to widen toward the left in the axial direction, and the abutment portion 54 of the valve portion 51, which is also tapered to widen toward the left in the axial direction, comes into contact with and seats on the valve seat 40a.

[0072] 3, the right end face 25b of the second portion 25 in the rod portion 20 and the left end face 15b of the second portion 15 in the valve housing 10 are spaced apart in the axial direction by a slight axial distance Δ13. Also, the right end face 26b of the third portion 26 in the rod portion 20 and the left end face 16b of the third portion 16 in the valve housing 10 are spaced apart in the axial direction by a slight axial distance Δ15.

[0073] The axial distance Δ13 and the axial distance Δ15 are approximately the same in length (Δ13=Δ15). In this embodiment, the axial distance Δ13 and the axial distance Δ15 are approximately the same in length, but they may be different.

[0074] Furthermore, when the valve 50 is closed, the axial distances Δ13 and Δ15 are longer than the radial distances Δ12 and Δ14 (Δ13, Δ15>Δ12, Δ14).

[0075] Furthermore, when the valve 50 is closed, the right end face 25b of the rod portion 20 and the left end face 15b of the valve housing 10, and the right end face 26b of the rod portion 20 and the left end face 16b of the valve housing 10 are closest in the axial direction within the movable range of the movable body 56. In other words, when the valve 50 is closed, the flow path cross-sectional areas of the third gap S13 and the fifth gap S15 are smallest.

[0076] Returning to FIG. 4, when the valve 50 is closed, the valve portion 51 receives a force (F) due to the pressure P1 of the working fluid in the primary pressure space S1, where the effective pressure receiving area A of the valve portion 51 and the effective pressure receiving area B of the large diameter portion 22 are positive, and the rightward axial direction is positive. P1 ) = (P1 × (AB)), and the force due to the pressure P2 of the working fluid in the secondary pressure space S2 (F P2 ) = -(P2 × (AB)) and the biasing force of the coil spring 85 (F sp ) is acting on the valve portion 51 (i.e., the right direction is positive, and the force F rod =F P1 -F P2 +F sp is at work).

[0077] At this time, the working fluid in the primary pressure space S1 acts on the axial left end surface of the valve portion 51. The primary pressure space S1 and the back space S3 are connected by the through hole 13 provided in the valve housing 10, so the working fluid in the primary pressure space S1 flows into the back space S3.

[0078] In this way, the working fluid flowing into the primary pressure space S1 and the back space S3 is the working fluid of the same primary pressure P1 supplied from the inlet port 11. In addition, since the effective pressure receiving area A of the valve portion 51 and the effective pressure receiving area B of the large diameter portion 22 are equal (A=B), the force (F) acting on the valve portion 51 due to the pressures P1 and P2 of the working fluid is P1 ),(F P2 ) are both nearly zero.

[0079] That is, the right direction is positive, and the valve portion 51 is substantially subjected to a force F rod =F sp As a result, the valve portion 51 is pressed in the valve closing direction, and the valve 50 is closed.

[0080] Next, the energized state of the displacement control valve V1 will be described. As shown in Fig. 5, in the energized state (i.e., during normal control, or so-called duty control), the displacement control valve V1 generates an electromagnetic force (F sol ) is the force F rod Exceeds (F sol >Frod ), the movable core 84 is pulled toward the center post 82, i.e., to the left in the axial direction, and the movable body 56 fixed to the movable core 84 moves together with it to the left in the axial direction, i.e., in the valve opening direction, causing the abutment portion 54 of the valve portion 51 to move away from the valve seat 40a and opening the valve 50.

[0081] When the valve 50 is open, the right end face 25b of the rod portion 20 and the left end face 15b of the valve housing 10 are separated axially by an axial distance Δ13'. Also, the right end face 26b of the rod portion 20 and the left end face 16b of the valve housing 10 are separated axially by an axial distance Δ15'. The axial distances Δ13' and Δ15' when the valve is open are longer than the axial distances Δ13 and Δ15 when the valve is closed (Δ13, Δ15<Δ13', Δ15'). Also, the axial distances Δ13' and Δ15' are the same distance.

[0082] On the other hand, the radial distance Δ12 of the second gap S12 and the radial distance Δ14 of the fourth gap S14 do not change regardless of the opening degree of the valve 50.

[0083] At this time, an electromagnetic force (F sol ), and a force F rod is acting on the valve portion 51 (i.e., the right direction is positive, and the force F rod -F sol is at work).

[0084] In this way, the displacement control valve V1 is driven by the electromagnetic force (F sol ) and the biasing force of the coil spring 85 (F sp The pressure P1 of the working fluid in the primary pressure space S1 can be appropriately controlled by adjusting the valve opening of the valve 50, which is adjusted by balancing the pressure P1 and the pressure P2.

[0085] Next, the flow of the working fluid within the gap S10 when the valve is closed will be described.

[0086] 3, when the valve 50 is closed, the working fluid flows in the first gap S11 to the left in the axial direction, that is, from the high-pressure back space S3 to the low-pressure secondary pressure space S2, as indicated by the arrow FL1. Note that the thickness and length of the arrows in FIG. 3 are exaggerated for ease of explanation.

[0087] The working fluid flowing through the first gap S11 flows into the second gap S12, which has a smaller flow path cross-sectional area than the first gap S11, as indicated by an arrow FL2. Because the second gap S12 functions as a throttle, a pressure loss occurs in the working fluid flowing through the second gap S12 due to friction between the outer circumferential surface 24a of the first portion 24 and the inner circumferential surface 15a of the second portion 15.

[0088] As shown by arrow FL3, the working fluid flowing through the second gap S12 flows into the third gap S13, which has a larger cross-sectional area than the first gap S11. When the working fluid flowing in the axial direction along the second gap S12 is redirected by approximately 90 degrees toward the third gap S13, which extends in the radial direction, a pressure loss in the working fluid increases. For ease of explanation, an example is shown in which a vortex is generated near the connection between the second gap S12 and the third gap S13. The same applies to the illustration of vortices in the following examples.

[0089] The working fluid flowing through the third gap S13 flows into the fourth gap S14, which has a smaller flow path cross-sectional area than the third gap S13, as indicated by arrow FL4. When the working fluid flowing in the radial direction along the third gap S13 is redirected at approximately 90 degrees toward the fourth gap S14 extending in the axial direction, a pressure loss occurs in the working fluid.

[0090] Furthermore, since the fourth gap S14 functions as a throttle, the working fluid flowing through the fourth gap S14 experiences a pressure loss due to friction between the outer peripheral surface 25a of the second portion 25 and the inner peripheral surface 16a of the third portion 16.

[0091] The working fluid flowing through the fourth gap S14 flows into a fifth gap S15, which has a larger flow path cross-sectional area than the fourth gap S14, as indicated by an arrow FL5. When the working fluid flowing in the axial direction along the fourth gap S14 is redirected by approximately 90 degrees toward the fifth gap S15, which extends in the radial direction, a pressure loss occurs in the working fluid.

[0092] As described above, a gap S10 connecting the secondary pressure space S2 and the back space S3 is formed between the rod portion 20 and the valve housing 10. This gap S10 has a bent portion E, and at least a portion of it is defined by the guide hole 10e. The second gap S12, the third gap S13, and the fourth gap S14 are defined by the inner circumferential surface of the valve housing 10, which constitutes the guide hole 10e, and the outer circumferential surface of the rod portion 20.

[0093] This causes a pressure loss of the working fluid when the direction of the working fluid flowing through the gap S10 from the high-pressure side, the back space S3, toward the secondary pressure space S2 changes at the bend E, thereby reducing leakage of the working fluid from the back space S3 to the secondary pressure space S2.

[0094] Furthermore, multiple bends E1 to E3 are formed in the gap S10, and pressure loss occurs in the working fluid at each of the bends E1 to E3, causing the fluid pressure of the working fluid to gradually decrease as it moves toward the secondary pressure space S2. In the fifth gap S15 of the gap S10, which is closest to the secondary pressure space S2, there is almost no pressure difference between the fluid pressure therein and the fluid pressure in the secondary pressure space S2, making it possible to achieve a state in which there is almost no leakage of the working fluid into the secondary pressure space S2.

[0095] Furthermore, when the valve 50 is closed, the flow path cross-sectional area of ​​each of the bent portions E1 to E3 is smallest. Specifically, the flow path cross-sectional area of ​​the bent portions E1 to E3 changes depending on the valve opening degree, and when the valve 50 is closed, the flow path cross-sectional area of ​​the third gap S13 and the fifth gap S15 is smallest, so it is possible to increase the pressure loss of the working fluid that occurs in the bent portions when the valve is closed.

[0096] Furthermore, when the valve 50 is closed, the right end face 25b of the second portion 25 of the rod portion 20 and the left end face 15b of the second portion 15 of the valve housing 10 are spaced apart in the axial direction. Similarly, the right end face 26b of the third portion 26 of the rod portion 20 and the left end face 16b of the third portion 16 of the valve housing 10 are spaced apart in the axial direction. As a result, when the valve 50 is closed, the right end face 25b does not come into contact with the left end face 15b, and the right end face 26b does not come into contact with the left end face 16b, so that the valve portion 51 can be reliably seated on the valve seat 40a.

[0097] Furthermore, a right end face 25b of the second portion 25 of the rod portion 20 and a left end face 15b of the second portion 15 of the valve housing 10 are formed between the outer peripheral surface of the rod portion 20 and the inner peripheral surface of the valve housing 10 that defines the guide hole 10e. As a result, bent portions E1, E2 are formed on both radial sides of a third gap S13 formed between the right end face 25b and the left end face 15b. In other words, the second gap S12, the third gap S13, and the fourth gap S14 form a crank shape, and the direction of the flow of the working fluid changes at each of the bent portions E1, E2, thereby increasing the pressure loss of the working fluid.

[0098] Furthermore, the right end face 26b, which is a side face of the rod portion 20, and the left end face 16b, which is a side face of the valve housing 10, face each other in the axial direction. This forms a bent portion E3 on the outlet side of the gap S10, i.e., on the secondary pressure space S2 side, which effectively prevents the working fluid from flowing out from the gap S10 to the secondary pressure space S2.

[0099] Further, the right end faces 25b, 26b of the rod portion 20 and the left end faces 15b, 16b of the valve housing 10 are perpendicular to the axial direction. That is, the pressure loss of the working fluid can be increased at the bent portions E1 to E3 including the right end faces 25b, 26b and the left end faces 15b, 16b.

[0100] Furthermore, the axial length of the inner peripheral surfaces 15a, 16a continuing to the left end faces 15b, 16b, and the axial length of the outer peripheral surfaces 24a, 25a continuing to the right end faces 25b, 26b, i.e., the axial lengths of the second gap S12 and the fourth gap S14, which are throttle spaces, can be ensured to be long, thereby improving the sealing performance of the gap S10.

[0101] Furthermore, the effective pressure-receiving area B of the large diameter portion 22, i.e., the effective pressure-receiving area B of the rod portion 20, is equal to the effective pressure-receiving area A of the valve portion 51, i.e., the effective pressure-receiving area A of the valve 50. This cancels out the force of the fluid pressure in the back space S3 acting on the rod portion 20 and the force of the fluid pressure in the primary pressure space S1 acting on the valve portion 51. In addition, since the force of the fluid pressure in the secondary pressure space S2 acting on the rod portion 20 and the force of the fluid pressure in the secondary pressure space S2 acting on the valve portion 51 are canceled out, the movable body 56 can be moved with precision regardless of the fluid pressures in the primary pressure space S1, the secondary pressure space S2, and the back space S3.

[0102] The outer circumferential surface of the large diameter portion 22 and the guide hole 10e increase in diameter in a stepped manner toward the left in the axial direction, which simplifies assembly of the displacement control valve V1 because assembly is completed by inserting the movable body 56 into the guide hole 10e from the left in the axial direction.

[0103] In the first embodiment, the opposing surfaces that face each other in the axial direction, that is, the left end surface 15b of the valve housing 10 and the right end surface 25b of the rod portion 20, and the left end surface 16b of the valve housing 10 and the right end surface 26b of the rod portion 20, are illustrated as being perpendicular to the axial direction, but the opposing surfaces may also be inclined in the axial direction.

[0104] Furthermore, in the first embodiment, a configuration in which the primary pressure space, secondary pressure space, and back surface space are formed in that order from left to right in the axial direction has been exemplified, but this is not limiting, and the positions of the primary pressure space and secondary pressure space may be reversed. For reference, Fig. 6 shows a first modified example in which the arrangement of the primary pressure space S1' and secondary pressure space S2' is reversed in the axial direction from that of the first embodiment.

[0105] Furthermore, although the above embodiment has been described as a normally closed valve, the present invention is not limited to this and a normally open valve may also be used. For reference, Fig. 7 shows a second modification in which a coil spring 851 is disposed between the movable iron core 84 and the sleeve 87, so that the abutment portion 54 of the valve portion 51 moves away from the valve seat 40a when not energized, thereby opening the valve 501. [Example]

[0106] Next, a displacement control valve according to a second embodiment will be described with reference to Fig. 8. Note that a description of the same configuration as in the first embodiment will be omitted.

[0107] 8, in the displacement control valve V2 of the second embodiment, an inner land 10g extending in the radially inner direction is formed between the recess 10a and the communication hole 10b in the valve housing 10. A through-hole 10h penetrating in the axial direction is formed in the inner land 10g.

[0108] The guide hole 101e of the valve housing 10 is formed so that its diameter increases stepwise toward the right in the axial direction. Specifically, the inner circumferential surface of the valve housing 10 that defines the guide hole 101e has two surfaces 102 extending in the axial direction and one surface 103 extending radially between the axial surfaces 102.

[0109] The left end of the movable body 561 in the axial direction is a valve portion 511. The valve portion 511 has a larger diameter than the through-hole 10h. The valve portion 511 is disposed axially to the right of the inner land 10g, i.e., in the secondary pressure space S2.

[0110] The movable body 561 is biased axially leftward by a coil spring (not shown). As a result, the left end surface 511a of the valve portion 511 contacts the edge portion 511b, which serves as the valve seat, of the through-hole 10h in the inner land 10g, thereby closing the valve 502. In this manner, in the second embodiment, the left end surface 511a of the valve portion 511 and the edge portion 511b of the through-hole 10h in the inner land 10g constitute the valve 502.

[0111] The outer peripheral surface of the insertion portion 221, which is inserted into the guide hole 101e of the rod portion 201, is formed so that its diameter increases stepwise toward the right in the axial direction. Specifically, the outer peripheral surface of the insertion portion 221 has two surfaces 202 extending in the axial direction and one surface 203 extending radially between the axial surfaces 202. The rod portion 201 also has an opposing surface 204 that axially faces the right surface 10j of the inner land 10f of the valve housing 10.

[0112] The surface 102 of the valve housing 10 and the surface 202 of the insertion portion 221 are radially opposed surfaces that face each other in the radial direction. The surface 103 of the valve housing 10 and the surface 203 of the insertion portion 221, and the right surface 10j of the valve housing 10 and the opposed surface 204 of the rod portion 201 are axially opposed surfaces that face each other in the axial direction.

[0113] When the valve 502 is closed, the surface 103 of the valve housing 10 and the surface 203 of the insertion part 221 are positioned closest to each other in the movable range of the movable body 561. Also, the right surface 10j of the valve housing 10 and the opposing surface 204 of the rod portion 201 are positioned closest to each other in the movable range of the movable body 561.

[0114] In this way, multiple bends are formed in the gap between the rod portion 201 and the valve housing 10, which causes pressure loss when the working fluid flows through the gap, thereby preventing the working fluid from leaking from the back space S3 to the secondary pressure space S2 when the valve 502 is closed.

[0115] 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.

[0116] For example, in the first and second embodiments, the valve element and the rod element are integrally formed, but the present invention is not limited to this, and the valve element and the rod element may be formed as separate members. Also, the valve element has been exemplified as having a tapered shape, but this can be freely modified.

[0117] In the first embodiment, the coil spring 85 is a compression spring, but it may be, for example, a tension spring. Also, it is not limited to a coil spring, and may be a leaf spring or the like.

[0118] In addition, in the first and second embodiments, the coil spring is disposed in the rear space, but the location of the biasing means may be freely changed. For example, the biasing means may be disposed in the primary pressure space or the secondary pressure space.

[0119] Furthermore, in the first and second embodiments, the effective pressure receiving area of ​​the valve element and the effective pressure receiving area of ​​the rod element are equal to each other, but the effective pressure receiving area of ​​the valve element and the effective pressure receiving area of ​​the rod element may be different.

[0120] Furthermore, in the first and second embodiments, the valve is a displacement control valve, but it may be, for example, an expansion valve disposed between a condenser and an evaporator in an air conditioning system.

[0121] In addition, in the first and second embodiments, the communicating means is a through hole provided in the valve housing, but this is not limited to this, and the communicating means may be a communicating passage that directly communicates the rear space and the control chamber.

[0122] In addition, in the first and second embodiments, the outer circumferential surface of the rod insertion portion and the guide hole have a stepped diameter increasing or decreasing toward the left in the axial direction, but as long as a bent portion is formed in the gap between the rod and the valve housing, the diameter does not have to increase or decrease in a stepped manner. Furthermore, the number of steps of the outer circumferential surface of the rod insertion portion and the guide hole may be freely changed.

[0123] In addition, in the first and second embodiments, the through hole provided in the valve housing itself is used as the guide hole, but the valve housing may be formed from multiple components. For example, the valve housing may be formed from a valve housing main body and a cylindrical body fitted and fixed within the valve housing main body, with the through hole in the cylindrical body serving as the guide hole.

[0124] Furthermore, in the first and second embodiments, a plurality of bent portions are formed in the gap between the rod and the valve housing, but it is sufficient that at least one bent portion is formed in the gap.

[0125] Furthermore, in the first and second embodiments, the flow path cross-sectional area of ​​the bent portion is smallest when the valve is closed, but the flow path cross-sectional area of ​​the bent portion may be smallest when the valve is open. [Explanation of symbols]

[0126] 10 Valve housing 10e Guide hole 11 Inlet port 12 Exit Port 13 Through hole (communication means) 15a Inner peripheral surface (diametrically opposed surface) 15b Left end surface (axially opposing surface) 16a Inner peripheral surface (radially opposing surface) 16b Left end surface (axially opposing surface) 20 Rod part (rod element, rod) 22 Large diameter section 24a Outer surface (radially opposing surface) 25a Outer peripheral surface (radially opposing surface) 25b Right end surface (axially opposing surface) 26b Right end surface (axially opposing surface) 40 Valve seat member 40a Valve seat 50 valves 51 Valve section (valve element, valve body) 54 Contact part 56 Movable body 80 Solenoid (drive source) 201 Rod part (rod element, rod) 221 Insertion site 501,502 Valve 511 Valve section (valve element, valve body) 511a Left end surface 511b End (valve seat) 561 Movable body A, B Effective pressure area E,E1,E2,E3 Bend part S1,S1' Primary pressure space S2,S2' Secondary pressure space S3 back space S10 Gap S11 First gap S12 Second gap S13 Third gap S14 4th gap S15 5th gap V1, V2 capacity control valve

Claims

1. a valve housing having a primary pressure space, a secondary pressure space, and a back space adjacent to one of the primary pressure space and the secondary pressure space; a valve seat disposed between the primary pressure space and the secondary pressure space; a rod that is inserted into a guide hole of the valve housing that is provided between the one space and the back space and that is driven in the axial direction by a drive source; a valve body that is seated on or separated from the valve seat by driving the rod; a communication means for communicating the back space with the other of the primary pressure space and the secondary pressure space, A valve in which a gap separate from the communication means connecting the one space and the back space is formed between the rod and the valve housing, and the gap has a bent portion.

2. 2. The valve according to claim 1, wherein the flow path cross-sectional area of ​​the bent portion is smallest when the valve is closed.

3. The valve according to claim 1 , wherein when the valve is closed, a pair of axially opposing surfaces that constitute the bent portion and that are opposed in the axial direction are spaced apart in the axial direction.

4. 4. The valve according to claim 3, wherein the side surface of the rod and the side surface of the valve housing are the pair of axially opposing surfaces.

5. The valve according to claim 3 , wherein the pair of axially opposing surfaces are perpendicular to the axial direction.

6. 2. The valve of claim 1, wherein the bend is crank-shaped.

7. 7. A valve according to claim 1, wherein the effective pressure-receiving area of ​​said rod is equal to the effective pressure-receiving area of ​​said valve.