valve

Abstract

Provided is a valve which can be moved in a direction in which a valve body is separated from a valve seat with good precision.　A bellows 60 is extensible in the axial direction, is disposed spanning a valve body 51 and a valve housing 10, and is disposed on the side of the valve body 51 axially opposite a valve seat 10f.

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 pressure control valve that adjusts the pressure of hydrogen gas supplied to a fuel cell, as shown in Patent Document 1. The pressure control valve in Patent Document 1 includes a valve housing having a primary pressure space to which hydrogen gas is supplied from a gas supply source, a secondary pressure space to which pressure-adjusted hydrogen gas is supplied to a nozzle portion of the fuel cell, a valve hole that communicates the primary pressure space and the secondary pressure space, a valve seat provided on the secondary pressure space side of the valve hole, a rod that is movable in the axial direction by a solenoid and has a tip that passes through the primary pressure space and the valve hole and is positioned in the secondary pressure space, and a valve element that is positioned in the secondary pressure space and seats on or releases from the valve seat as the rod moves.

[0005] The primary pressure chamber and the back space where the solenoid is located are hermetically separated by a bellows, one axial end of which is fixed to the rod and the other axial end of which is fixed to the inner surface of the valve housing, preventing hydrogen from the primary pressure chamber from leaking toward the solenoid. The effective pressure-receiving area of ​​this bellows is equal to the opening area of ​​the valve hole. This cancels out the force of fluid pressure in the primary pressure chamber that moves the valve disc away from the valve seat and the force of fluid pressure in the primary pressure chamber that moves the valve disc toward the valve seat. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] WO 2011 / 132438 (page 6, Figure 2) Summary of the Invention [Problem to be solved by the invention]

[0007] In a valve such as that disclosed in Patent Document 1, the force acting on the valve disc is canceled by the fluid pressure in the primary pressure space, so that fluctuations in the pressure of the upstream gas supplied to the primary pressure space can be suppressed from affecting the movement of the valve disc. However, the fluid pressure in the secondary pressure space, which fluctuates depending on the use mode of the valve, always acts in a direction to move the valve disc closer to the valve seat, so when moving the valve disc in a direction away from the valve seat, the stroke distance of the valve disc changes depending on the fluid pressure in the secondary pressure space, and there is a risk that the valve disc cannot be moved in a direction away from the valve seat with precision.

[0008] The present invention has been made in view of these problems, and has as its object to provide a valve that can move the valve body in a direction away from the valve seat with high precision. [Means for solving the problem]

[0009] In order to solve the above problems, the valve of the present invention comprises: a valve housing in which a primary pressure space, a secondary pressure space, and a valve hole communicating these spaces are formed; a valve seat provided in the valve housing closer to the secondary pressure space than the valve hole; a rod disposed within the valve housing so as to be movable in an axial direction by a drive source; a valve body that is disposed in the secondary pressure space and that is seated on or separated from the valve seat by movement of the rod, A valve provided with a pressure-receiving surface that applies a force to the rod in a direction opposite to the secondary pressure space due to the pressure in the primary pressure space, A bellows that is expandable and contractible in the axial direction is disposed across the valve body and the valve housing on the axially opposite side of the valve body from the valve seat. According to this, since the bellows that can expand and contract in the axial direction is positioned on the axially opposite side of the valve seat on the valve body, the pressure-receiving area on which the fluid pressure in the secondary pressure space acts on the valve body can be reduced, and the effect of the force acting on the valve body by the fluid pressure in the secondary pressure space can be reduced, allowing the valve body to be moved in a direction away from the valve seat with precision.

[0010] The bellows may have a sealed internal space. This allows for a high degree of freedom in valve placement, regardless of the ambient environment in which the bellows is installed.

[0011] The interior space may be in a vacuum state. According to this, since the internal space is in a vacuum state, it is possible to reduce the change in the force acting on the valve body from the bellows due to the change in volume of the internal space caused by the expansion and contraction of the bellows.

[0012] The effective pressure-receiving area of ​​the bellows may be equal to the effective area of ​​the valve. According to this, the force acting on the valve element due to the fluid pressure in the secondary pressure space is canceled, so that the valve element can be moved with high precision regardless of the fluid pressure in the secondary pressure space.

[0013] The valve may further include a biasing means for biasing the valve body in one axial direction, the biasing means being arranged in parallel with the bellows. According to this, since the biasing means and the bellows are arranged in parallel at positions close to the axial direction, the expansion and contraction of the bellows in the axial direction can be stabilized by the biasing force of the biasing means.

[0014] The valve housing may have a movable member to which one end of the bellows is sealedly fixed and whose axial position is adjustable. According to this, by moving the movable member, the degree of expansion and contraction of the bellows and the biasing force of the biasing means can be adjusted simultaneously.

[0015] The biasing means may be located within the bellows. According to this, the fluid pressure in the secondary pressure space does not act on the biasing means, so that the biasing force of the biasing means can be appropriately applied to the valve body.

[0016] The bellows may be arranged to be rotatable relative to the valve housing. This makes it possible to suppress twisting of the bellows when the valve is actuated.

[0017] The vacuum state in the present invention is defined by the Japanese Industrial Standards (JIS Z 8126) as "a state of space filled with gas at a pressure lower than normal atmospheric pressure." [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a cross-sectional view showing a pressure 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 state in which the pressure control valve is closed. [Figure 3] FIG. 4 is an enlarged cross-sectional view of a main part showing a state in which the pressure control valve is opened. [Figure 4] FIG. 6 is a cross-sectional view showing a pressure control valve according to a second embodiment of the present invention. [Figure 5] FIG. 10 is an enlarged cross-sectional view of a main part of a pressure control valve according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] 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 pressure control valve as an example, the present invention can also be applied to other uses. [Example]

[0020] A pressure control valve according to a first embodiment will be described with reference to Figures 1 to 3. Hereinafter, 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 pressure 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 pressure 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 pressure control valve.

[0021] The pressure control valve of the present invention adjusts the pressure of hydrogen gas (hereinafter simply referred to as "fluid"), which is a working fluid supplied from a gas supply source, and supplies the adjusted hydrogen gas to the outside.

[0022] As shown in FIG. 1 , the pressure control valve V1 of the first embodiment includes a primary pressure space S1 into which fluid flows from a gas supply source, a secondary pressure space S2 containing fluid to be supplied to the outside, and a valve housing 10 having a valve hole 10d that communicates the primary pressure space S1 and the secondary pressure space S2. The flow rate from the primary pressure space S1 to the secondary pressure space S2 is varied by adjusting the current flowing through a coil 86 constituting a solenoid 80 serving as a driving source to control the opening and closing of a valve 50, thereby variably controlling the control pressure Pc in the secondary pressure space S2. Note that a discharge fluid at a discharge pressure Pd from the gas supply source is constantly supplied to the primary pressure space S1. The control pressure Pc in the secondary pressure space S2 can be reduced by narrowing the valve aperture of the valve 50 in the pressure control valve V1, and increased by widening the valve aperture of the valve 50.

[0023] In the pressure control valve V1 of the first embodiment, the valve 50 is composed of a valve element 51 and a valve seat 10f formed on the left surface of a partition wall portion 10e extending toward the inner diameter side of the valve housing 10, and the valve 50 is opened and closed by the seal member 15 disposed on the right side of the valve element 51 moving toward and away from the valve seat 10f in the axial direction. The valve 50 of the present embodiment is a normally closed valve that is closed in a non-energized state.

[0024] The pressure control valve V1 is used by being attached to a manifold member (not shown) having passages communicating with a gas supply source and the outside. The pressure control valve V1 is mainly composed of a valve housing 10 made of a metal material, a valve disc 51 arranged within the valve housing 10 so as to be able to reciprocate in the axial direction, a rod member 20 arranged on the axial right side of the valve disc 51, a solenoid 80 connected to the valve housing 10 and applying a driving force to the rod member 20 and the valve disc 51, a first bellows 30 arranged in a sealed state between the valve housing 10 and the rod member 20, and a second bellows 60 fixed in a sealed state to the axial left side of the valve disc 51 and serving as a bellows that defines an independent internal space S4.

[0025] As shown in Figures 1 and 2, the valve housing 10 comprises a valve housing main body 10A (hereinafter simply referred to as the main body 10A), and a cover member 13 and a shaft member 16 as movable members whose axial positions can be adjusted relative to the main body 10A.

[0026] A primary pressure space S1 is formed on the axial right side of the main body 10A, which communicates with a gas supply source through a plurality of inlet ports 11 that penetrate radially, and a secondary pressure space S2 is formed on the axial left side of the main body 10A, which communicates with the outside through a plurality of outlet ports 12 that penetrate radially.

[0027] The main body 10A is formed with a recess 10a that is recessed from the left end in the axial direction to the right in the axial direction and has an open left end in the axial direction.

[0028] The left axial end of the main body 10A is closed by the cover member 13 and the shaft member 16, and the space surrounded by the inner circumferential surface constituting the recess 10a, the right end face, the cover member 13, and the shaft member 16 forms the secondary pressure space S2. The cover member 13 is screwed and fixed to the left end of the main body 10A, and its fixed position in the axial direction relative to the main body 10A is adjustable.

[0029] In addition, a through hole 13a is formed in the center of the cover member 13, penetrating in the left-right direction, and the left end shaft portion 16c of the shaft member 16 is inserted into the through hole 13a so as to be rotatable relative to the cover member 13, and the large diameter flange portion 16d of the shaft member 16 abuts against the right end face of the cover member 13.

[0030] The shaft member 16 has, from the left in the axial direction, a left-end shaft portion 16c, a large-diameter flange portion 16d, a flange portion 16a, and a right-end shaft portion 16b. The large-diameter flange portion 16d and the flange portion 16a are arranged spaced apart in the axial direction, and the portion connecting the large-diameter flange portion 16d and the flange portion 16a is formed with a diameter smaller than the large-diameter flange portion 16d and the flange portion 16a, but larger than the diameter of the left-end shaft portion 16c and the right-end shaft portion 16b.

[0031] Between the shaft member 16 and the valve body 51, a body 61 of a second bellows 60 that is expandable and contractible in the axial direction and a coil spring 14 as a biasing means that biases the valve body 51 axially to the right, which is the closing direction of the valve 50, are arranged in parallel.

[0032] The second bellows 60 is composed of a metal accordion-shaped bellows body 61, an axial member 16 that closes the opening at the left axial end of the body 61, and a valve body 51 that closes the opening at the right axial end of the body 61.

[0033] More specifically, the body 61 is disposed between the flange 16a of the shaft member 16 and a flange 54 (see FIG. 2) that is provided at approximately the center of the axial direction of the valve body 51 and faces the flange 16a in the axial direction, and is fixed by any fixing means such as welding. This hermetically separates the internal space S4 of the second bellows 60 from the secondary pressure space S2.

[0034] The internal space S4 is in a vacuum state, being filled with gas at a pressure lower than atmospheric pressure. The body 61 of the second bellows 60 may be made of a material other than metal.

[0035] Coil spring 14 is a compression spring and is disposed inside second bellows 60, i.e., in internal space S4. More specifically, tip shaft portion 52 of valve body 51 and right end shaft portion 16b of shaft member 16 are inserted into the inside of coil spring 14. This prevents axial wobble of coil spring 14 (see FIG. 2). That is, coil spring 14 and body portion 61 of second bellows 60 overlap in the radial direction.

[0036] The biasing force of the coil spring 14 maintains the large diameter flange portion 16d of the shaft member 16 in contact with the right end surface of the cover member 13. Furthermore, since the internal space S4 is in a vacuum state, it is easy to adjust the biasing force of the coil spring 14 based on the vacuum.

[0037] 1, the main body 10A has a recess 10c formed on the inner diameter side of the right end in the axial direction, recessed axially leftward, and a communication hole 10b that communicates in the axial direction is formed between the recess 10a and the recess 10c. The communication hole 10b has a smaller diameter than the recesses 10a and 10c.

[0038] Specifically, the main body 10A is provided with a partition wall 10e extending radially inward to separate the recess 10a from the communication hole 10b, and a valve hole 10d penetrating left and right is formed in the radial center of the partition wall 10e. This valve hole 10d communicates with the axial left side of the communication hole 10b.

[0039] A first bellows 30 is fixed in the recess 10c in a sealed manner. The space surrounded by the first bellows 30 and the communication hole portion 10b forms a primary pressure space S1.

[0040] The first bellows 30 has a cylindrical body 31 with bellows that can expand and contract in the axial direction, a fixing plate portion 32 that closes the opening at the left axial end of the body 31, and a ring portion 33 that is provided at the right axial end of the body 31 and is press-fitted into the recess 10c.

[0041] The body 31, the fixing plate 32, and the ring 33 are made of metal. The fixing plate 32 and the ring 33 are formed to be thicker than the body 31 and are more rigid than the body 31. The body 31, the fixing plate 32, and the ring 33 may be made of different materials, but it is preferable that the fixing plate 32 and the ring 33 be more rigid than the body 31. The body 31, the fixing plate 32, and the ring 33 may also be made of a material other than metal.

[0042] The left axial surface of the fixed plate portion 32 is a tapered surface 32d that extends so as to reduce in diameter as it extends leftward. The inner diameter side portion of this tapered surface 32d functions as a pressure-receiving surface that faces the pressure-receiving surface on the right axial end surface of the large diameter portion 53 of the valve body 51.

[0043] Furthermore, a protruding shaft portion 32a extending axially to the left is formed in the radial center of the left end of the tapered surface 32d of the fixing plate portion 32, and the left axial end portion of the protruding shaft portion 32a, i.e., the tip portion, is press-fitted and fixed into a recess 53a of the valve body 51 (described later) through the valve hole 10d. This protruding shaft portion 32a and the rod member 20 function as a rod that transmits a moving force to the valve body 51.

[0044] A fitting recess 33a recessed axially to the left is formed on the inner diameter side of the right end of the ring portion 33 in the axial direction, and a cylindrical protrusion 82d of a center post 82 described later is inserted into the fitting recess 33a.

[0045] As shown in FIG. 2, the valve body 51 is formed with a tip shaft portion 52, a flange portion 54, and a large diameter portion 53 in this order from the left end in the axial direction.

[0046] The distal end shaft portion 52 has a smaller diameter than the flange portion 54 and the large diameter portion 53, and the flange portion 54 has a smaller diameter than the large diameter portion 53. The large diameter portion 53 has a larger diameter than the valve hole 10d of the valve housing 10.

[0047] The end face on the right side of the axial direction of the large diameter portion 53 is provided with a recess 53a that is recessed axially to the left side in the radial center, and an annular groove portion 53b that opens axially to the right side and is formed to surround the outer diameter side of the recess 53a, and an annular sealing member 15 made of a rubber material is press-fitted into the annular groove portion 53b.

[0048] The seal member 15 is capable of abutting against a valve seat 10f provided on the periphery of the valve hole 10d at the left axial end face of the partition wall portion 10e of the valve housing 10, and when in abutment against the valve seat 10f, reduces the amount of fluid leakage between the valve seat 10f and the valve element 51 to almost zero. Note that the seal member 15 is not limited to being made of rubber, and may be made of synthetic resin, metal, or the like. Furthermore, the valve seat 10f may be made of a separate member from the valve housing 10 which is press-fitted and fixed into the valve hole 10d.

[0049] Returning to FIG. 1 , the solenoid 80 is mainly composed of a casing 81 having an opening 81a that is open to the left in the axial direction, a substantially cylindrical center post 82 that is inserted into the opening 81a of the casing 81 and is located between the inner diameter side of the casing 81 and the inner diameter side of the valve housing 10, a rod member 20 that is inserted through the center post 82 and is movable back and forth in the axial direction, with its left axial end located within the valve housing 10, a movable iron core 84 into which the right axial end of the rod member 20 is inserted and fixed, an excitation coil 86 that is wound around the outside of the center post 82 via a bobbin, and a bottomed cylindrical sleeve 87 that houses part of the center post 82, the movable iron core 84, and part of the rod member 20.

[0050] The center post 82 is formed from a rigid body that is a magnetic material such as iron or silicon steel, and includes a cylindrical portion 82b that extends axially and has an insertion hole 82c through which the rod member 20 is inserted, and a cylindrical protrusion 82d that extends axially leftward from the inner diameter side of the left end face of the cylindrical portion 82b.

[0051] The portion on the right side of the insertion hole 82c in the axial direction is a small-diameter hole portion 82e that is slightly larger in diameter than the rod member 20, and the portion on the left side of the insertion hole 82c in the axial direction is a large-diameter hole portion 82f that is larger in diameter than the small-diameter hole portion 82e. An annular bearing 17 is disposed in this large-diameter hole portion 82f, which guides the movement of the rod member 20 in the axial direction and restricts the inclination of the rod member 20.

[0052] The cylindrical protrusion 82d is inserted into the fitting recess 33a of the first bellows 30 so as to fit therewith.

[0053] Furthermore, the center post 82 is formed with a notch 82g that is cut out to open radially outward from the left end of the cylindrical protrusion 82d to the left end of the cylindrical portion 82b. The bottom of the notch 82g has its left end extending radially outward in an arc shape so as to protrude radially inward in cross section from a position axially left of the bearing 17 and axially right of the left end face of the cylindrical protrusion 82d. In other words, the left end of the notch 82g communicates with the large-diameter hole 82f of the insertion hole 82c.

[0054] When the cylindrical protrusion 82d of the center post 82 is fitted into the fitting recess 33a of the first bellows 30, the notch 82g forms a passage that connects the left axial portion of the back space S3 within the solenoid 80 with the space outside the pressure control valve V1. In other words, the left axial portion of the back space S3 is at atmospheric pressure.

[0055] The left axial portion of the rear space S3 includes the space inside the first bellows 30 and the space in the large diameter hole portion 82f to the left of the bearing 17 in the axial direction.

[0056] The sleeve 87 has a cylindrical member 87a into which part of the center post 82 and part of the movable iron core 84 are inserted, and a cap member 87b that is U-shaped in cross section and opens on the left axial side and is connected to the right axial end of the cylindrical member 87a.

[0057] A port 87c is formed in the cap member 87b so as to penetrate radially, and the port 87c connects the axially right side of the back space S3 in the solenoid 80 with the space outside the pressure control valve V1. In other words, the axially right side of the back space S3 is at atmospheric pressure.

[0058] In addition, the axial direction in the back space S3 right The side region includes the space in the large diameter hole portion 82f to the right of the bearing 17 in the axial direction, the space in the small diameter hole portion 82e of the insertion hole 82c, and the spaces on the left and right of the movable iron core 84 in the sleeve 87.

[0059] A small gap is formed between the inner peripheral surface of the bearing 17 and the outer peripheral surface of the rod member 20, and the axially right and left portions of the back space S3 are connected to each other. In other words, the back space S3 within the solenoid 80 is the space mainly within the sleeve 87 on the back side of the valve body 51, separated from the primary pressure space S1.

[0060] The rod member 20 is inserted through the insertion hole 82c of the center post 82, the right axial end of the rod member 20 is inserted into and fixed to the movable iron core 84, and the left axial end of the rod member 20 is inserted into the body portion 31 of the first bellows 30. The left axial end of the rod member 20 is inserted into and fixed to a recess 32c recessed axially leftward in the right end surface of a shaft portion 32b that extends axially rightward from the right surface of the fixing plate portion 32. The left axial end of the rod member 20 may be fixed to the right surface of the fixing plate portion 32 by adhesive, welding, or the like.

[0061] 2, the effective pressure-receiving area B of the valve element 51 is the same as the opening area of ​​the valve hole 10d. The effective pressure-receiving area A of the first bellows 30 and the effective pressure-receiving area C of the second bellows 60 are both formed to be the same as the effective pressure-receiving area B of the valve element 51 (A = B = C). The pressure of the working fluid acting on the valve element 51 will be described in detail later.

[0062] Next, the opening and closing operation of the pressure control valve V1 will be described.

[0063] First, the de-energized state of the pressure control valve V1 will be described. As shown in Figures 1 and 2, in the de-energized state of the pressure control valve V1, the valve element 51 is pressed axially rightward, i.e., in the valve closing direction, by the biasing force of the coil spring 14, so that the seal member 15 of the valve element 51 is seated on the valve seat 10f, and the valve 50 is closed.

[0064] At this time, the rightward axial direction is taken as positive, and the valve body 51 is subjected to the biasing force (F sp ) and the force (F P1 ) and the force (F P2 ) and the force due to atmospheric pressure P3 in the back space S3 (F P3 ) is acting on the valve body 51 (i.e., the right direction is positive, and the force F rod =F sp +F P1 +F P2 -F P3 The internal space S4 is in a vacuum state, and the force F acting on the valve body 51 due to the pressure in the internal space S4 is P4 is approximately zero, so the explanation is omitted here.

[0065] Furthermore, at this time, the force due to the pressure P1 of the working fluid in the primary pressure space S1 acting in the axial direction of the valve body 51 and the force due to the pressure P2 of the working fluid in the secondary pressure space S2 are almost canceled out, so that the valve body 51 is not affected by the working fluid in the primary pressure space S1 and the secondary pressure space S2.

[0066] Specifically, in the primary pressure space S1, the pressure P1 of the working fluid acts on the effective pressure-receiving area A of the first bellows 30 in the right axial direction, and also acts on the effective pressure-receiving area B of the valve body 51 in the left axial direction. That is, the valve body 51 is subjected to a force (F P1 )=P1×(AB) is acting.

[0067] Since the effective pressure receiving area B of the valve element 51 is equal to the effective pressure receiving area A of the first bellows 30 (A=B), the force (F P1 ) is almost zero.

[0068] On the other hand, the pressure P2 of the working fluid in the secondary pressure space S2 acts in the axial right direction on the area obtained by subtracting the effective pressure-receiving area C of the second bellows 60 from the effective pressure-receiving area B of the valve body 51 at the axial left end face of the valve body 51. That is, the valve body 51 is subjected to a force (F P2 )=P2×(BC) is acting.

[0069] The effective pressure-receiving area B of the valve body 51 is equal to the effective pressure-receiving area C of the second bellows 60 ( C =B), the force (F P2 ) is almost zero.

[0070] That is, the right direction is positive, and the valve body 51 is substantially subjected to a force F rod =F sp -F P3 is acting, and the biasing force of the coil spring 14 (F sp ) is the force due to pressure P3 (F P3 ) is greater than (F sp >F p3 ), the valve 50 is pressed in the valve closing direction and is closed.

[0071] Next, the energized state of the pressure control valve V1 will be described. As shown in Fig. 3, in the energized state (i.e., during normal control, so-called duty control), the pressure control valve V1 generates an electromagnetic force (F sol ) is the force F rod Exceeds (F sol >F rod), the movable iron core 84 is pulled toward the center post 82, i.e., to the left in the axial direction, and the rod member 20 fixed to the movable iron core 84 and the valve body 51 move together to the left in the axial direction, i.e., in the valve opening direction, causing the seal member 15 of the valve body 51 to move away from the valve seat 10f and opening the valve 50.

[0072] Furthermore, when the solenoid 80 is driven, the tip shaft portion 52 of the valve body 51 comes into contact with the right end shaft portion 16b of the shaft member 16, thereby restricting the valve body 51 from further moving away from the valve seat 10f, that is, from lifting off.

[0073] At this time, the valve body 51 is subjected to an electromagnetic force (F sol ), and a force F rod is acting on the valve body 51 (i.e., the right direction is positive, and the force F rod -F sol is at work).

[0074] In this way, the pressure control valve V1 is operated by the electromagnetic force (F sol ) and the biasing force of the coil spring 14 (F sp ) and the force due to pressure P3 (F P3 ) and the difference (F sp -F p3 The pressure P2 of the working fluid in the secondary pressure space S2 can be appropriately controlled by adjusting the valve opening of the valve 50, which is adjusted by balancing the pressure P2 and the pressure P2.

[0075] In this embodiment, a configuration has been exemplified in which the biasing force of the first bellows 30 itself and the biasing force of the second bellows 60 itself hardly act on the valve body 51, but the biasing force of the first bellows 30 itself and the biasing force of the second bellows 60 itself may also act.

[0076] As described above, in the pressure control valve V1 of this embodiment, the second bellows 60, which is axially expandable and contractible, is provided across the valve body 51 and the shaft member 16 at a position on the axial opposite side of the valve seat 10f on the valve body 51. Therefore, the second bellows 60 can reduce the effective pressure-receiving area over which the fluid pressure in the secondary pressure space S2 acts on the valve body 51, and can reduce the effect of the force exerted on the valve body 51 by the fluid pressure in the secondary pressure space S2.

[0077] Therefore, the valve element 51 can be moved in a direction away from the valve seat 10f with high precision. Also, because the valve element 51 can be moved in a direction away from the valve seat 10f with a small electromagnetic force, the configuration of the solenoid 80 can be made smaller. This is particularly useful when the opening area of ​​the valve hole 10d is made large to control a large flow rate of the control fluid.

[0078] In addition, the pressure-receiving surface of the valve body 51 (i.e., the axial right end surface of the large diameter portion 53) and the pressure-receiving surface of the first bellows 30 opposite to said pressure-receiving surface can reduce the effect of the force caused by the pressure P1 of the working fluid in the primary pressure space S1 acting on the valve body 51, so that the valve body 51 can be moved in a direction away from the valve seat 10f with precision.

[0079] Furthermore, the second bellows 60 has a sealed internal space S4, and in this state the second bellows 60 is able to expand and contract in the axial direction. This eliminates the need for a flow path for fluid to enter and exit the internal space S4 when the second bellows 60 expands and contracts in the axial direction, thereby simplifying the structure. In other words, there is a high degree of freedom in the placement of the pressure control valve V1, regardless of the ambient environment in which the second bellows 60 is installed.

[0080] Furthermore, because the internal space S4 is in a vacuum state, it is possible to reduce the change in force acting on the valve body 51 due to a change in the volume of the internal space S4 accompanying the expansion and contraction of the second bellows 60. For example, when the second bellows 60 is compressed in the axial direction, it is possible to prevent the fluid pressure in the internal space S4 from increasing, allowing the second bellows 60 to make a large stroke in the compression direction. Furthermore, it is possible to reduce the force acting on the valve body 51 due to the pressure in the internal space S4 to approximately zero.

[0081] Furthermore, the effective pressure-receiving area C of the second bellows 60 is equal to the opening area of ​​the valve hole 10d, i.e., the effective pressure-receiving area B of the valve body 51. This cancels out the force of the fluid pressure in the secondary pressure space S2 acting on the valve body 51, allowing the valve body 51 to move with precision regardless of the fluid pressure in the secondary pressure space S2.

[0082] In addition, the effective pressure-receiving area A of the first bellows 30 is equal to the effective pressure-receiving area B of the valve body 51. This cancels out the force of the fluid pressure in the primary pressure space S1 acting on the valve body 51, allowing the valve body 51 to move with precision regardless of the fluid pressure in the primary pressure space S1.

[0083] In addition, the coil spring 14 that biases the valve body 51 to the right in the axial direction is arranged in parallel with the second bellows 60 so as to overlap radially, and therefore the biasing force of the coil spring 14 can stabilize the axial expansion and contraction of the second bellows 60.

[0084] Furthermore, the valve housing 10 includes a cover member 13 and a shaft member 16 to which one end of the second bellows 60 is hermetically fixed and whose axial position relative to the main body 10A is adjustable. By moving the cover member 13 to change the distance from the valve element 51, the degree of expansion and contraction of the second bellows 60 and the biasing force of the second bellows 60 can be adjusted simultaneously.

[0085] 1 to 3, when changing the distance between cover member 13 and shaft member 16 and valve body 51, the screw-engagement depth of cover member 13 can be changed to any desired depth by rotating only cover member 13 relative to main body 10A while restricting the rotation of shaft member 16. In this way, twisting of second bellows 60 and first bellows 30 can be avoided when changing the distance between cover member 13 and shaft member 16 and valve body 51.

[0086] Furthermore, with the above-described configuration, the second bellows 60 is rotatable relative to the main body 10A of the valve housing 10, so that the second bellows 60 can be prevented from twisting when the valve 50 is operated.

[0087] Furthermore, since the internal space S4 is in a vacuum state, it is easy to adjust the biasing force of the coil spring 14 based on the vacuum.

[0088] Furthermore, since the coil spring 14 is disposed within the second bellows 60, the fluid pressure in the secondary pressure space S2 and the flow of the working fluid do not act on the coil spring 14, and the spring force of the coil spring 14 can be applied appropriately to the valve body 51. [Example]

[0089] Next, a pressure control valve according to a second embodiment will be described with reference to Fig. 4. Note that a description of the same configuration as in the first embodiment will be omitted.

[0090] In the pressure control valve V2 of the second embodiment, a coil spring 140 serving as a biasing means is disposed in the back space S3.

[0091] More specifically, in solenoid 800, center post 820 is disposed on the axial right side inside coil 86, and movable core 840 is disposed on the axial left side inside coil 86. A recess 820a recessed axially to the right is formed in the radial center of the left end of center post 820, and coil spring 140 is disposed in recess 820a.

[0092] Coil spring 140 has a diameter slightly smaller than that of recess 820a, is formed so as to be longer in the axial direction than the axial length of recess 820a in a compressed state, and is disposed between center post 820 and movable core 840. In other words, coil spring 140 is disposed axially separated from second bellows 60 and does not overlap with it in the radial direction.

[0093] With the above-described configuration, when the pressure control valve V2 is in a de-energized state, the valve element 51 moves axially leftward due to the biasing force of the coil spring 140, and the seal member 15 is separated from the valve seat 10f. In other words, the pressure control valve V2 is a normally open valve.

[0094] As in the first embodiment, in this pressure control valve V2, the force due to the pressure of the working fluid in the secondary pressure space S2 acting in the axial direction of the valve body 51 is almost canceled, so when the pressure control valve V2 is changed from an energized state to a de-energized state, the pressure of the working fluid in the secondary pressure space S2 does not affect the movement of the valve body 51 in the valve opening direction.

[0095] Furthermore, since the coil spring 140 is disposed within the rear space S3, the fluid pressure in the primary pressure space S1 and the secondary pressure space S2, which are higher than atmospheric pressure, is prevented from acting on the coil spring 140, and the spring force of the coil spring 140 can be applied appropriately to the valve body 51.

[0096] Furthermore, the diameter of the coil spring 140 is slightly smaller than the diameter of the recess 820a, and there is almost no gap between the inner surface of the center post 820 that forms the recess 820a and the coil spring 140, so the inner surface of the center post 820 prevents the coil spring 140 from tilting. [Example]

[0097] Next, a pressure control valve according to a third embodiment will be described with reference to Fig. 5. Note that the description of the components that are the same as those shown in the first embodiment will be omitted.

[0098] In the pressure control valve V3 of the third embodiment, a coil spring 240 serving as a biasing means is arranged in parallel within the secondary pressure space S2, that is, on the outer diameter side of the body portion 61 of the second bellows 60. This allows the biasing force of the coil spring 240 to stabilize the expansion and contraction of the second bellows 60 in the axial direction.

[0099] Furthermore, since there is no need to install the coil spring 240 inside the second bellows 60, it is easy to install the coil spring 240. More specifically, the inner diameter of the coil spring 240 is formed to be larger than the large-diameter flange portion 16d of the shaft member 16, and the left end portion of the coil spring 240 in the axial direction abuts against the right surface of the cover member 13.

[0100] Therefore, after connecting the valve body 51 and the shaft member 16 with the body 61 of the second bellows 60, the coil spring 240 is inserted axially from the shaft member 16 side and positioned on the outer diameter side of the body 61, and then the left end shaft portion 16c of the shaft member 16 is inserted into the through hole 13a of the cover member 13, thereby unitizing the second bellows 60 (i.e., the body 61, the shaft member 16, the valve body 51), the coil spring 240, and the cover member 13, and the assembly work of the pressure control valve V3 can be performed easily.

[0101] 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.

[0102] For example, in the above-described first to third embodiments, the effective pressure-receiving area of ​​the second bellows is made equal to the effective pressure-receiving area of ​​the valve disc to cancel the force of the fluid pressure in the secondary pressure space acting on the valve disc. However, this is not limiting, and any other configuration may be used as long as the effect of the force of the fluid pressure in the secondary pressure space acting on the valve disc is reduced. For example, the effective pressure-receiving area of ​​the second bellows may be slightly smaller or larger than the effective pressure-receiving area of ​​the valve disc. In this case where the effective pressure-receiving areas of the second bellows and the valve disc are different, it is preferable to make the effective pressure-receiving area of ​​the second bellows smaller than the effective pressure-receiving area of ​​the valve disc to make it easier to maintain the valve disc in contact with the valve seat.

[0103] In addition, in the above-described first to third embodiments, the effective pressure-receiving area of ​​the first bellows is made equal to the effective pressure-receiving area of ​​the valve disc to cancel the force of the fluid pressure in the primary pressure space acting on the valve disc, but this is not limiting, and any other configuration may be used as long as the effect of the force of the fluid pressure in the primary pressure space acting on the valve disc is reduced. For example, the effective pressure-receiving area of ​​the first bellows may be slightly smaller or larger than the effective pressure-receiving area of ​​the valve disc.

[0104] In addition, in the above-described Examples 1 to 3, the primary pressure space and the back space are separated by the first bellows, but the primary pressure space and the back space may be separated by sliding contact between the rod and the valve housing or the solenoid case. In other words, the primary pressure space and the back space may communicate with each other through a small gap between the outer peripheral surface of the rod and the inner peripheral surface of the valve housing or the solenoid case.

[0105] Furthermore, in the above-described Examples 1 to 3, a form was exemplified in which a pressure-receiving surface was provided on the first bellows, which applied a force to the rod in the valve closing direction due to the pressure in the primary pressure space, but a small diameter portion may be provided on the valve body side of the rod and a large diameter portion on the solenoid side of the rod, and the step between the small diameter portion and the large diameter portion may be used as the pressure-receiving surface.

[0106] Furthermore, in the first to third embodiments, the valve body and the rod are configured as separate members, but the present invention is not limited to this, and the valve body and the rod may be integrated.

[0107] In addition, in the above-described Examples 1 to 3, the internal space of the second bellows is sealed, but the internal space of the second bellows may be connected to the external space, as long as the fluid pressure in the external space is lower than the fluid pressure in the secondary pressure space.

[0108] Furthermore, in the above-described Examples 1 to 3, the internal space of the sealed second bellows is in a vacuum state, but the internal space of the second bellows may be filled with a fluid whose pressure is lower than the fluid pressure in the secondary pressure space.

[0109] In addition, in the first to third embodiments, the biasing means is a compression spring, but it may be a pull spring. Also, the biasing means is not limited to a coil spring, but may be a leaf spring or the like.

[0110] Furthermore, in Example 1, a form in which the biasing means is arranged in the internal space, in Example 2, a form in which the biasing means is arranged in the rear space, and in Example 3, a form in which the biasing means is arranged in the secondary pressure space are exemplified, but the biasing means may also be arranged in the primary pressure space.

[0111] Furthermore, in the above-described Examples 1 to 3, the movable member constitutes the valve housing, but it is not necessary for it to constitute the valve housing. Specifically, the movable member and the valve housing do not have to form a secondary pressure space, and it is sufficient that the movable member is movable relative to the valve housing and that its position relative to the valve housing can be fixed.

[0112] Furthermore, in the first to third embodiments, the valve element is in annular surface contact with the valve seat, but it may be in annular line contact, for example.

[0113] In addition, in the above-described Examples 1 to 3, the effective pressure-receiving area B of the valve body is equal to the opening area of ​​the valve hole 10d, but the valve body may be configured to contact at a point with an outer diameter greater than the valve hole, and may be larger than the opening area of ​​the valve hole.

[0114] Furthermore, in the first and second embodiments, a solenoid is used as a drive source for moving the valve element, but a drive source other than a solenoid may be used to move the valve element.

[0115] Furthermore, in the above-described first to third embodiments, examples have been described in which the valve is a pressure control valve, but the valve may also be, for example, an expansion valve disposed between a condenser and an evaporator in an air conditioning system, or a displacement control valve incorporated in a variable displacement compressor in an air conditioning system. [Explanation of symbols]

[0116] 10 Valve housing 10A main body 10d valve hole 10f valve seat 13 Lid member (movable member) 14 Coil spring (biasing means) 16 Shaft member (movable member) 20 Rod member (rod) 30 First Bellows 32a Protruding shaft (rod) 50 valves 51 Valve body 60 Second Bellows 61 Torso 80 Solenoid (drive source) 140,240 coil spring 800 Solenoid (drive source) A~C Effective pressure area P1~P3 pressure S1 Primary pressure space S2 Secondary pressure space S3 back space S4 interior space V1~V3 pressure control valve

Claims

1. a valve housing in which a primary pressure space, a secondary pressure space, and a valve hole communicating these spaces are formed; a valve seat provided in the valve housing closer to the secondary pressure space than the valve hole; a rod disposed within the valve housing so as to be movable in an axial direction by a drive source; a valve body that is disposed in the secondary pressure space and that is seated on or separated from the valve seat by movement of the rod, a valve provided with a pressure-receiving surface that applies a force to the rod in a direction opposite to the secondary pressure space due to the pressure in the primary pressure space, the valve housing includes a main body, a cover member provided axially movable relative to the main body and having a through hole extending therethrough in the axial direction, and a shaft member inserted into the through hole of the cover member so as to be rotatable relative to the main body, A valve in which a bellows that is expandable and contractible in the axial direction is disposed across the valve body and the shaft member on the side of the valve body opposite to the valve seat in the axial direction.

2. 2. The valve of claim 1, wherein the bellows has a sealed interior space.

3. 3. The valve of claim 2, wherein the interior space is under vacuum.

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

5. 5. A valve according to claim 1, further comprising a biasing means for biasing said valve element in one axial direction, said biasing means being arranged in parallel with said bellows.

6. 6. The valve of claim 5, wherein said biasing means is disposed within said bellows.

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