Valve

Abstract

The invention provides a valve capable of smoothly changing the pressure of back pressure fluid. The present invention is provided with: a housing (60) having a high-pressure space (S2) into which a high-pressure fluid (Pd) flows, a back-pressure space (S3) into which a back-pressure fluid (Pb) flows, and a passage (65a) provided between the high-pressure space (S2) and the back-pressure space (S3); and a valve body (61) for controlling the opening degree of the passage (65a). And a biasing means (62) that biases the valve body (61) in the opening direction, the valve body (61) having: a high-pressure receiving surface (A-B) that receives the pressure of the high-pressure space (S2) as the force in the opening direction; and a back pressure receiving surface (A) that receives the pressure of the back pressure space (S3) as a force in the closing direction.

Description

Technical Field

[0001] This invention relates to a valve, such as a pressure control valve. Background Technology

[0002] Scroll compressors are among the most widely used compressors in various industrial fields. These compressors are not only highly efficient but also low in noise, and are therefore widely used in various applications such as refrigeration cycles.

[0003] The scroll compressor has the following structure: a scroll compression mechanism consisting of a fixed scroll with a scroll-shaped vortex and a movable scroll with a scroll-shaped vortex, and an eccentric mechanism mounted on a rotating shaft to rotate the movable scroll eccentrically. The movable scroll slides relative to the fixed scroll while rotating eccentrically, thereby pressurizing the fluid supplied as refrigerant from the low-pressure chamber on the outer diameter side of the two scrolls, and causing the high-pressure refrigerant to be discharged from the discharge port formed at the center of the fixed scroll.

[0004] In this type of scroll compressor, the refrigerant compressed by the scroll compressor mechanism is discharged into the discharge chamber. When the pressure in the discharge chamber increases, it will forcefully move the movable scroll away from the fixed scroll.

[0005] Patent Document 1 describes a scroll compressor with a connecting passage between a discharge chamber and a back pressure chamber formed on the back side of a movable scroll. A throttling orifice is provided on this connecting passage. A portion of the refrigerant compressed in the discharge chamber is supplied to the back pressure chamber after being depressurized and adjusted through the throttling orifice, pushing the movable scroll towards the fixed scroll and thus preventing the movable scroll from leaving the fixed scroll.

[0006] Furthermore, the scroll compressor has a pressure regulating valve that releases pressure from the back pressure chamber to the low pressure chamber for adjustment. The pressure regulating valve opens when the force pushing the valve body towards the opening direction from the back pressure chamber exceeds the force pushing the valve body towards the closing direction from the low pressure chamber pressure and the spring preload. This allows refrigerant from the back pressure chamber to flow into the low pressure chamber, thereby reducing the pressure in the back pressure chamber. This prevents the movable scroll from being excessively compressed against the fixed scroll due to increased back pressure, thus hindering the smooth operation of the movable scroll.

[0007] Existing technical documents Patent documents Patent Document 1: International Publication No. 2022 / 009769 (pages 8 and 9) Figure 1 ) Summary of the Invention

[0008] The problem that the invention aims to solve However, in the scroll compressor of Patent Literature 1, since a portion of the refrigerant of the discharge chamber is supplied to the back pressure chamber at a constant amount through the orifice, there is a problem that the pressure of the back pressure chamber changes less than the pressure of the discharge chamber, and it takes time for the pressure of the back pressure chamber to reach an appropriate pressure.

[0009] The present application has been achieved in view of the above-described problems, and aims to provide a valve capable of smoothly changing the pressure of a back pressure fluid.

[0010] Solution to the problem To solve the above-described problems, the valve of the present application comprises: a housing having a high pressure space into which a high pressure fluid flows, a back pressure space into which a back pressure fluid flows, and a passage provided between the high pressure space and the back pressure space; and a valve body that controls the opening degree of the passage; and a force applying unit that applies a force to the valve body in an opening direction, the valve body has: a high pressure pressure receiving surface that receives the pressure of the high pressure space as a force in the opening direction; and a back pressure pressure receiving surface that receives the pressure of the back pressure space as a force in a closing direction.

[0011] Accordingly, the opening degree of the passage at the time of start-up is appropriately ensured, and the opening degree of the passage can be changed during operation, so that adjustment of the pressure of the back pressure fluid can be smoothly performed.

[0012] Optionally, the back pressure pressure receiving surface is larger than the high pressure pressure receiving surface.

[0013] Accordingly, the effect of the pressure of the back pressure fluid, which is relatively low with respect to the pressure of the high pressure fluid, can be increased, so that responsiveness is improved.

[0014] Optionally, the housing has a low pressure space into which a low pressure fluid flows, the valve body has a low pressure pressure receiving surface that receives the pressure within the low pressure space as a force in the opening direction.

[0015] Accordingly, the accuracy of adjustment of the pressure of the back pressure fluid is improved.

[0016] Optionally, a sealing unit is provided between the high pressure space and the low pressure space.

[0017] Accordingly, leakage of the valve interior from the high pressure space to the low pressure space can be prevented, and efficiency reduction can be prevented.

[0018] Optionally, the force applying unit is disposed in the low pressure space.

[0019] According to this, it is possible to provide a force applying unit that does not obstruct the flow of the back pressure fluid in the back pressure space.

[0020] Optionally, a stopper is provided to the valve, which limits the relative movement of the valve body with respect to the housing.

[0021] According to this, it is possible to make the maximum opening degree of the passage substantially constant, and thus adjust the pressure of the back pressure fluid in a short time at the time of start-up.

[0022] Optionally, the valve body is configured to be able to block the passage.

[0023] According to this, it is possible to reliably suppress excessive increase in the pressure of the back pressure fluid.

[0024] Optionally, the passage is conical in shape.

[0025] According to this, even if the valve opening degree is narrow, the flow efficiency is good.

[0026] Optionally, the portion of the valve body that opposes the conical shape of the passage is spherical in shape.

[0027] According to this, since line contact is formed with the passage in the circumferential direction, it is possible to balance the sealing property and the opening / closing responsiveness. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a schematic configuration view of a scroll compressor to which the valve of Embodiment 1 of the present application is applied.

[0029] Figure 2 is a cross-sectional view of the valve of Embodiment 1 of the present application.

[0030] Figure 3 is a cross-sectional view of the valve of Embodiment 2 of the present application. DETAILED DESCRIPTION

[0031] The following describes the form of the valve to which the present application is applied, based on an embodiment.

[0032] Embodiment 1 The valve to which Embodiment 1 is applied will be described with reference to Figure 1 , Figure 2 of the present application is applied to a rotary machine including an eccentric mechanism, such as a scroll compressor C that sucks, compresses, and discharges a refrigerant as a fluid for an air conditioning system of an automobile or the like. In this embodiment, the refrigerant is a gas in a state in which a mist of lubricating oil is mixed.

[0033] First, the scroll compressor C will be described. As shown in Figure 1As shown, the scroll compressor C is mainly composed of a housing 1, a rotating shaft 2, an inner sleeve 3, a scroll compression mechanism 4, a side seal 7, a thrust plate 8, and a drive motor M.

[0034] The housing 1 is composed of a cylindrical sleeve 11 and a lid 12 that blocks an opening of the sleeve 11. An opening of the sleeve 11 on the opposite axial side to the opening blocked by the lid 12 is blocked by the drive motor M.

[0035] Inside the sleeve 11, a low-pressure chamber 20 that receives a low-pressure refrigerant (i.e., a suction fluid Ps as a low-pressure fluid) from an unillustrated refrigerant circuit through a suction port 10, a high-pressure chamber 30 that is an exhaust chamber for exhausting a high-pressure refrigerant (i.e., an exhaust fluid Pd as a high-pressure fluid) compressed by the scroll compression mechanism 4, and a back-pressure chamber 50 that receives a part of the refrigerant compressed by the scroll compression mechanism 4 together with lubricating oil (i.e., a control fluid Pb as a back-pressure fluid) via a back-pressure control valve V1 are formed. In addition, the back-pressure chamber 50 is formed inside a cylindrical inner sleeve 3 housed inside the sleeve 11.

[0036] The lid 12 is formed with an exhaust communication path 13 that communicates the unillustrated refrigerant circuit with the high-pressure chamber 30. In addition, the lid 12 is formed with a part of a back-pressure communication path 14 that communicates the high-pressure chamber 30 with the back-pressure chamber 50, which branches from the exhaust communication path 13. In addition, the exhaust communication path 13 is provided with a lubricating oil separator 6 that separates lubricating oil from the refrigerant.

[0037] The inner sleeve 3 is fixed in a state where axial end portions thereof abut against an end plate 41a of a fixed scroll 41 that constitutes the scroll compression mechanism 4. In addition, a radially-through suction communication path 15 is formed in a side wall of the inner sleeve 3. That is, the low-pressure chamber 20 is formed from the outside of the inner sleeve 3 to the inside thereof via the suction communication path 15. The suction fluid Ps is supplied to the inside of the housing 3 through the suction communication path 15 and is sucked into the scroll compression mechanism 4.

[0038] The scroll compression mechanism 4 is mainly composed of the fixed scroll 41 fixed in a sealed state with respect to the lid 12 and a movable scroll 42 housed inside the inner sleeve 3.

[0039] The fixed scroll 41 is made of metal and has a scroll-shaped scroll wrap 41b provided so as to protrude toward the movable scroll 42 from a surface of a circular plate-shaped end plate 41a (i.e., an end face of the end plate 41a that faces the movable scroll 42). In addition, in the fixed scroll 41, a recessed portion 41c recessed in the opposite direction to the lid 12 is formed on the inner diameter side of the back face of the end plate 41a (i.e., an end face of the end plate 41a that abuts against the lid 12), and the high-pressure chamber 30 is divided by the recessed portion 41c and the lid 12.

[0040] The movable scroll 42 is made of metal and has a scroll-like wrap 42b protruding from the surface of a circular plate-like end plate 42a (i.e., the end surface of the end plate 42a facing the fixed scroll 41) toward the fixed scroll 41. Further, the movable scroll 42 has a boss 42c protruding from the center of the back surface of the end plate 42a. In the boss 42c, an eccentric portion 2a formed in the rotary shaft 2 is relatively rotatably fitted. In this embodiment, an eccentric mechanism that eccentrically rotates the rotary shaft 2 is configured by the eccentric portion 2a of the rotary shaft 2 and a balance weight portion 2b protruding from the rotary shaft 2 to the radially outer side.

[0041] When the rotary shaft 2 is rotationally driven by the drive motor M, the eccentric portion 2a is eccentrically rotated, and the movable scroll 42 is relatively slid in conjunction with the eccentric rotation while maintaining the posture with respect to the fixed scroll 41. At this time, the movable scroll 42 is eccentrically rotated with respect to the fixed scroll 41, and in conjunction with this rotation, the contact positions of the wraps 41b, 42b move in the rotation direction in order, and the compression chambers 40 formed between the wraps 41b, 42b gradually decrease in size as they move toward the center. Thus, the suction fluid Ps sucked into the compression chambers 40 from the low-pressure chamber 20 formed on the outer diameter side of the scroll compression mechanism 4 is compressed, and finally, the high-pressure discharge fluid Pd is discharged to the high-pressure chamber 30 through the discharge hole 41d provided at the center of the fixed scroll 41.

[0042] The side seal 7 is made of resin, has a rectangular cross section, and has a ring shape when viewed in the axial direction. The side seal 7 is fixed to the back surface of the end plate 42a of the movable scroll 42. The side seal 7 is formed with a sliding surface 7a that abuts against a sliding surface 8a formed in the thrust plate 8.

[0043] The thrust plate 8 is made of metal, has a circular ring shape, and has the seal ring 43 fixed thereto. The seal ring 43 abuts against the inner peripheral end surface of the inner sleeve 3. Thus, the thrust plate 8 functions as a thrust bearing that receives the axial load of the movable scroll 42 through the side seal 7.

[0044] Further, the side seal 7 and the seal ring 43 divide the low-pressure chamber 20 formed on the outer diameter side of the movable scroll 42 and the back pressure chamber 50 formed on the back side of the movable scroll 42 in the inside of the inner sleeve 3. The back pressure chamber 50 is formed as a closed space by the seal ring 44 fixed to the through hole 3a of the inner sleeve 3, which seals the gap between the through hole 3a and the rotary shaft 2 inserted through the through hole 3a.

[0045] Further, the back pressure communication path 14, which communicates the high-pressure chamber 30 and the back pressure chamber 50, is formed through the cover 12, the fixed scroll 41, and the inner sleeve 3, and the back pressure control valve V1 as a valve is provided in the back pressure communication path 14. In other words, the back pressure control valve V1 is provided inside the housing 1 that is isolated from the outside air.

[0046] The discharge fluid Pd of the partial high-pressure chamber 30 supplied to the back pressure control valve Vl together with the lubricating oil separated at the oil separator 6 is pressure-regulated as a control fluid Pb and supplied to the back pressure chamber 50.

[0047] Further, the inner sleeve 3 is formed with a relief hole 16 that penetrates in the radial direction and communicates the low-pressure chamber 20 with the back pressure chamber 50, and the relief hole 16 is provided with a throttle hole 45.

[0048] Next, the back pressure control valve Vl is explained. Figure 2 The back pressure control valve Vl of the present embodiment is explained below, with the left and right sides as viewed from the front side of the valve body 61 as the left and right sides of the back pressure control valve Vl. Figure 2

[0049] As shown in FIG. 1, the back pressure control valve Vl of the present embodiment 1 is mainly composed of a housing 60, a valve body 61, and a coil spring 62 as a force applying unit for applying a force to the valve body 61 in a direction away from the valve seat, i.e., in an opening direction of the valve. Figure 2 The housing 60 divides a low-pressure space S1 that communicates with the low-pressure chamber 20, a high-pressure space S2 that communicates with the high-pressure chamber 30, and a back pressure space S3 that communicates with the back pressure chamber 50. Further, the housing 60 is formed with a valve hole 65a as a passage that communicates the high-pressure space S2 and the back pressure space S3, and a through hole 64a that communicates the low-pressure space S1 and the high-pressure space S2. Further, the housing 60 need only divide at least a part of the low-pressure space S1, the high-pressure space S2, and the back pressure space S3.

[0050] The housing 60 is composed of a first divided body 63, a second divided body 64, and a third divided body 65 in this order from the right side.

[0051] The first divided body 63 has a peripheral wall 63a and a side wall 63b and is formed as a side-walled cylindrical shape that is open toward the axial left side.

[0052] The peripheral wall 63a is formed as a cylindrical shape that extends in the axial direction on the inner side thereof. The peripheral wall 63a is provided with a communication hole 63c that penetrates in the radial direction and communicates with the low-pressure chamber 20. In the present embodiment, the communication hole 63c is two and is uniformly distributed, but the number and arrangement thereof can be appropriately changed.

[0053] The inner diameter of the peripheral wall 63a is substantially the same in the axial direction.

[0054] The side wall 63b is formed as a circular plate shape that closes the right end of the peripheral wall 63a in the axial direction.

[0055] The inner diameter of the peripheral wall 63a is substantially the same in the axial direction.

[0056] ​Further, a cylindrical protrusion 63d is formed on the side wall 63b, the center of the left end face of which protrudes to the left in the axial direction. The coil spring 62 is fitted to the right end in the axial direction in the protrusion 63d. Thus, the right end in the axial direction of the coil spring 62 is positioned in the radial direction. Further, the right end in the axial direction of the coil spring 62 abuts against the side wall 63b.

[0057] The second divided body 64 has, in order from the left in the axial direction, a large-diameter peripheral wall 64b, a medium-diameter peripheral wall 64c, and a small-diameter peripheral wall 64d, and is formed in a cylindrical shape extending in the axial direction. The outer peripheral surfaces of the large-diameter peripheral wall 64b, the medium-diameter peripheral wall 64c, and the small-diameter peripheral wall 64d are substantially flush with each other. Hereinafter, the outer peripheral surface of the second divided body 64 is simply referred to as the outer peripheral surface.

[0058] The outer diameter of the second divided body 64 is substantially constant in the entire axial direction, and is substantially the same as or slightly larger than the inner diameter of the peripheral wall 63a of the first divided body 63.

[0059] The large-diameter peripheral wall 64b is a cylindrical shape extending in the axial direction. The large-diameter peripheral wall 64b is formed with communication holes 64e that penetrate in the radial direction and communicate with the high-pressure space S2. In the present embodiment, the communication holes 64e are two and are uniformly distributed, but the number and arrangement thereof can be appropriately changed.

[0060] The outer diameter end of the communication hole 64e is expanded in diameter, and an annular recess 64f that is open to the outer diameter side is formed, and communicates with the high-pressure chamber 30. The recess 64f is provided with a filter 66 for removing foreign matter such as contaminants contained in the refrigerant.

[0061] The medium-diameter peripheral wall 64c is a cylindrical shape extending to the right in the axial direction from the right end of the large-diameter peripheral wall 64b. The inner diameter of the medium-diameter peripheral wall 64c is smaller than the inner diameter of the large-diameter peripheral wall 64b.

[0062] The small-diameter peripheral wall 64d is a cylindrical shape extending to the right in the axial direction from the right end of the medium-diameter peripheral wall 64c. The inner diameter of the small-diameter peripheral wall 64d is smaller than the inner diameter of the medium-diameter peripheral wall 64c.

[0063] Further, an axial through-hole 64a is formed in the radial center of the small-diameter peripheral wall 64d.

[0064] The right end of the second divided body 64 is press-fitted and fixed inside the peripheral wall 63a of the first divided body 63. The space surrounded by the peripheral wall 63a and the side wall 63b of the first divided body 63 and the small-diameter peripheral wall 64d of the second divided body 64 is a low-pressure space S1 into which the intake fluid Ps flows.

[0065] The third divided body 65 has, in order from the left in the axial direction, a large-diameter peripheral wall 65b and a small-diameter peripheral wall 65c, and is formed in a stepped cylindrical shape.

[0066] The large-diameter peripheral wall 65b is a cylindrical shape extending in the axial direction.

[0067] The small-diameter peripheral wall 65c is a cylindrical shape extending from the right end of the large-diameter peripheral wall 65b to the right in the axial direction. The outer diameter of the small-diameter peripheral wall 65c is smaller than the outer diameter of the large-diameter peripheral wall 65b.

[0068] The outer diameter of the small-diameter peripheral wall 65c is substantially constant in the entire axial direction and is substantially the same as or slightly larger than the inner diameter of the large-diameter peripheral wall 64b of the second divided body 64.

[0069] An axial through-hole 65a that communicates with the high-pressure space S2 and the back-pressure space S3 is provided in the radial center of the large-diameter peripheral wall 65b and the small-diameter peripheral wall 65c, that is, in the radial center of the third divided body 65.

[0070] A tapered surface that expands the valve hole 65a toward the left is formed on the inner diameter side of the large-diameter peripheral wall 65b. This tapered surface becomes a valve seat 67 with which the large-diameter main body portion 61a of the valve body 61 is brought into contact and separation. That is, the large-diameter main body portion 61a and the valve seat 67, by the contact and separation of the housing 60 and the valve body 61, form a valve 70 that controls the opening and closing of the flow rate and the flow path.

[0071] Further, the left end of the inner diameter side of the large-diameter peripheral wall 65b is formed with a back-pressure space S3 that communicates with the back-pressure chamber 50. The back-pressure space S3 is recessed from the left end surface of the large-diameter peripheral wall 65b to the right in the axial direction, communicates with the valve hole 65a, and is open to the left in the axial direction.

[0072] The small-diameter peripheral wall 65c of the third divided body 65 is pressed into and fixed to the inner side of the large-diameter peripheral wall 64b of the second divided body 64. Further, the large-diameter peripheral wall 65b of the third divided body 65 abuts against the large-diameter peripheral wall 64b of the second divided body 64, thereby being axially positioned. The space surrounded by the large-diameter peripheral wall 64b, the medium-diameter peripheral wall 64c, and the small-diameter peripheral wall 64d of the second divided body 64, and the third divided body 65 is a high-pressure space S2 into which the discharge fluid Pd flows.

[0073] The valve body 61 has, in order from the left in the axial direction, a large-diameter main body portion 61a, a small-diameter main body portion 61b, and a medium-diameter main body portion 61c, and is formed in a stepped cylindrical shape.

[0074] The large-diameter main body portion 61a has a curved surface 61d that constitutes a part of a spherical surface and that is formed so as to gradually decrease in diameter as it goes from the left end thereof toward the right in the axial direction.

[0075] The large-diameter main body portion 61a is disposed across the high-pressure space S2 on the right in the axial direction of the valve seat 67 and the back-pressure space S3 on the left in the axial direction of the valve seat 67. That is, the pressure of the control fluid Pb and the pressure of the discharge fluid Pd act on the large-diameter main body portion 61a, respectively.

[0076] The small-diameter body portion 61b is formed in a cylindrical shape extending to the right in the axial direction from the right end of the large-diameter body portion 61a. The diameter of the small-diameter body portion 61b is substantially the same as the smallest diameter of the large-diameter body portion 61a.

[0077] The small-diameter body portion 61b is inserted in the valve hole 65a.

[0078] The medium-diameter body portion 61c is formed in a cylindrical shape extending to the right in the axial direction from the right end of the small-diameter body portion 61b, expanding in diameter, extending to the right in the axial direction at substantially the same diameter, and then contracting in diameter. The maximum diameter of the medium-diameter body portion 61c is larger than the diameter of the small-diameter body portion 61b but smaller than the maximum diameter of the large-diameter body portion 61a. In addition, the minimum diameter of the medium-diameter body portion 61c is substantially the same as the diameter of the small-diameter body portion 61b.

[0079] The medium-diameter body portion 61c is inserted in the through hole 64a and disposed across the low-pressure space S1 and the high-pressure space S2. That is, the pressure of the discharge fluid Pd and the pressure of the intake fluid Ps act on the medium-diameter body portion 61c, respectively.

[0080] The medium-diameter body portion 61c has an O-ring 68 as a sealing unit fitted to the outer periphery of the axial center. The O-ring 68 is fitted to the medium-inner-diameter peripheral wall 64c of the second divided body 64. The O-ring 68 seals between the medium-diameter body portion 61c and the medium-inner-diameter peripheral wall 64c while allowing the valve body 61 to move in the axial direction.

[0081] In addition, the O-ring 68 is continuous with the small-inner-diameter peripheral wall 64d on the right in the axial direction, that is, on the low-pressure space S1 side. That is, the O-ring 68 seals between the low-pressure space S1 and the high-pressure space S2. In addition, since the O-ring 68 abuts against the small-inner-diameter peripheral wall 64d, movement to the right in the axial direction by the force generated by the pressure difference between the pressure of the intake fluid Ps flowing into the low-pressure space S1 and the pressure of the discharge fluid Pd flowing into the high-pressure space S2 is prevented.

[0082] In addition, the right end of the medium-diameter body portion 61c is pressed into and fixed to a stopper 69. The stopper 69 is formed in an annular shape. The inner diameter of the stopper 69 is substantially the same as or slightly smaller than the outer diameter of the medium-diameter body portion 61c.

[0083] The right end of the medium-diameter body portion 61c protrudes further to the right in the axial direction than the right end edge of the stopper 69, and the left end of the coil spring 62 is fitted to the protruding portion. Thus, the left end of the coil spring 62 is positioned in the radial direction. In addition, the left end of the coil spring 62 abuts against the stopper 69.

[0084] As described above, the effective pressure receiving surface of the valve body 61, on which the pressure of the control fluid Pb acts, is substantially the same as the flow passage cross section A of the valve seat 67 at the position where the large-diameter body portion 61a is in line contact in the circumferential direction in the state where the large-diameter body portion 61a is seated on the valve seat 67. Hereinafter, the effective pressure receiving surface of the valve body 61, on which the pressure of the control fluid Pb acts, is referred to as "effective pressure receiving surface A".

[0085] The effective pressure receiving surface of the valve body 61, on which the pressure of the control fluid Pb acts, as a back pressure receiving surface, is substantially the same as the flow passage cross section A of the valve seat 67 at the position where the large-diameter body portion 61a is in line contact in the circumferential direction in the state where the large-diameter body portion 61a is seated on the valve seat 67. Hereinafter, the effective pressure receiving surface of the valve body 61, on which the pressure of the control fluid Pb acts, is referred to as "effective pressure receiving surface A".

[0086] The effective pressure receiving surface of the valve body 61, on which the pressure of the control fluid Pb acts, as a back pressure receiving surface, is substantially the same as the flow passage cross section A of the valve seat 67 at the position where the large-diameter body portion 61a is in line contact in the circumferential direction in the state where the large-diameter body portion 61a is seated on the valve seat 67. Hereinafter, the effective pressure receiving surface of the valve body 61, on which the pressure of the control fluid Pb acts, is referred to as "effective pressure receiving surface A".

[0087] That is, the effective pressure receiving surface A of the valve body 61, on which the pressure of the control fluid Pb acts, is larger than the effective pressure receiving surface (A-B) of the valve body 61, on which the pressure of the discharge fluid Pd acts (A > (A-B)).

[0088] The effective pressure receiving surface of the valve body 61, on which the pressure of the control fluid Pb acts, as a back pressure receiving surface, is substantially the same as the flow passage cross section A of the valve seat 67 at the position where the large-diameter body portion 61a is in line contact in the circumferential direction in the state where the large-diameter body portion 61a is seated on the valve seat 67. Hereinafter, the effective pressure receiving surface of the valve body 61, on which the pressure of the control fluid Pb acts, is referred to as "effective pressure receiving surface A".

[0089] Next, the opening and closing operation of the back pressure control valve V1 will be described. In the housing 60, the intake fluid Ps flows into the low pressure space S1, the discharge fluid Pd flows into the high pressure space S2, and the control fluid Pb flows into the back pressure space S3.

[0090] The valve body 61 is pushed toward the axial left side (i.e., the leftward direction is positive, and the forces F1 = F Ps +F Pd +F b act on the valve body 61) by the force (F Ps = Ps x B) generated by the pressure of the intake fluid Ps acting on the effective pressure receiving surface B, the force (F Pd = Pd x (A-B)) generated by the pressure of the discharge fluid Pd acting on the effective pressure receiving surface (A-B), and the pre-tightening force (F b ) of the coil spring 62.

[0091] Further, the valve body 61 is pushed toward the axial left side (i.e., the leftward direction is positive, and the forces F1 = F Ps +F Pd +F b act on the valve body 61) by the force (FPb = Pb x A) to the right side in the axial direction (i.e., the right direction is positive, and the force F2= FPb acts on the valve body 61).

[0092] When the force Fl exceeds the force F2, the valve body 61 moves to the left side in the axial direction (Fl > F2). Then, the stopper 69 abuts against the small inner diameter peripheral wall 64d of the second divided body 64 of the housing 60, thereby restricting the movement to the left side in the axial direction. In this state, the opening degree of the valve 70 is maximum. More specifically, it is preferable to be larger than the opening degree of the fixed orifice of Patent Document 1.

[0093] Here, in the present embodiment, the pre-tightening force (F b ) of the coil spring 62 and the effective pressure receiving surfaces A, B are adjusted so that the opening degree of the valve 70 is maximum when the pressures of the suction fluid Ps, the discharge fluid Pd, and the control fluid Pb are substantially the same. That is, the back pressure control valve Vl is normally open type.

[0094] More specifically regarding this point, when the scroll compressor C is stopped for a long time, the pressures of the suction fluid Ps, the discharge fluid Pd, and the control fluid Pb sometimes balance and become substantially the same.

[0095] In this case, when the scroll compressor C is started, the pressure of the discharge fluid Pd slightly rises, and the pressure of the suction fluid Ps slightly drops. At this time, the pressure of the suction fluid Ps is higher than the pressure range of the suction fluid Ps in the normal operation state during continuous operation, and the opening degree of the valve 70 remains maximum.

[0096] Thus, a large amount of the discharge fluid Pd is supplied to the back pressure chamber 50 through the valve 70, and therefore it is possible to immediately increase the pressure of the control fluid Pb.

[0097] After that, as the scroll compressor C continues to operate, the difference between the force Fl and the force F2 acting on the valve body 61 gradually decreases. Along with this, the valve body 61 moves in the valve closing direction. Then, when the force Fl and the force F2 balance, the valve body 61 seats on the valve seat 67. That is, the opening degree of the valve 70 mainly changes in the range from the opening degree larger than the fixed orifice of Patent Document 1 to the state where the valve 70 is blocked.

[0098] As described above, the back pressure control valve Vl of the present embodiment is normally open type, and the opening degree of the valve hole 65a is appropriately ensured at the time of starting the scroll compressor C, and therefore it is possible to smoothly perform the pressure adjustment of the control fluid Pb. Further, since the back pressure control valve Vl is normally open type, it is less likely to cause a back pressure shortage, and therefore it is easy to well control the compression efficiency of the scroll compression mechanism 4 even at the time of starting the scroll compressor C.

[0099] Further, the back pressure control valve Vl can change the opening degree of the valve hole 65a during the operation of the scroll compressor C, and thereby smoothly adjust the pressure of the control fluid Pb.

[0100] Further, since the effective pressure receiving surface A on which the pressure of the control fluid Pb acts is larger than the effective pressure receiving surface (A-B) on which the pressure of the discharge fluid Pd acts, the effect of the pressure of the control fluid Pb, which is relatively low compared to the pressure of the discharge fluid Pd, can be increased, thereby improving responsiveness.

[0101] Further, since the valve body 61 has the effective pressure receiving surface B on which the pressure of the suction fluid Ps acts, the pressure regulation accuracy of the control fluid Pb is improved.

[0102] Further, the back pressure control valve Vl seals the gap between the high pressure space S2 and the low pressure space Sl by the O-ring 68, and thus leakage of the discharge fluid Pd flowing into the high pressure space S2 to the low pressure space Sl is prevented. Thus, internal leakage of the valve is prevented, and efficiency reduction is prevented.

[0103] Further, since the coil spring 62 is disposed in the low pressure space Sl, the flow of the control fluid in the back pressure space S3 is not easily obstructed.

[0104] Further, since the back pressure control valve Vl is provided with the stopper 69, the maximum opening degree of the valve hole 65a can be made substantially constant. Thus, at the time of start of the scroll compressor C, the pressure of the control fluid Pb can be adjusted in a short time.

[0105] Further, since the valve body 61 is disposed so as to be able to block the valve hole 65a, excessive rise in the pressure of the control fluid Pb can be reliably suppressed.

[0106] Further, since the valve seat 67 of the valve hole 65a is a tapered shape, flow efficiency is good even if the valve opening degree is small.

[0107] Further, since the portion of the valve body 61 which opposes the valve seat 67 is a curved surface 61d, line contact is formed in the circumferential direction when seated on the valve seat 67, and both sealing property and opening / closing responsiveness can be taken into account.

[0108] Further, since the housing 60 is press-fitted and fixed to the first divided body 63 with the second divided body 64, the press-fitting amount can be changed within the press-fitting allowance range, and thus not only the pre-tightening force of the coil spring 62 but also the axial length of the housing 60 can be adjusted.

[0109] Further, since the valve body 61 is press-fitted and fixed to the stopper 69, the press-fitting amount can be changed within the press-fitting allowance range, and thus the stroke amount of the valve body 61, i.e., the maximum opening degree of the valve 70, can be adjusted.

[0110] Furthermore, when the valve 70 is at its maximum opening, the stop 69 abuts against the second segment 64 of the housing 60, sealing the gap between the stop 69 and the second segment 64. This not only makes it difficult for the discharged fluid Pd to leak from the high-pressure space S2 to the low-pressure space S1, but also ensures a larger effective pressure surface than the effective pressure surface B, thus making it easier to maintain the maximum opening of the valve 70.

[0111] Furthermore, the valve body 61 is adjusted and aligned with the axis of the second segment 64 by the elastic restoring force of the O-ring 68. As a result, the outer peripheral surface of the small-diameter main body 61b is less likely to slide into contact with the inner peripheral surface of the valve hole 65a when the valve body 61 moves axially, thereby reducing the generated friction.

[0112] Example 2 Next, refer to Figure 3 The valve involved in Example 2 will be described below. Additionally, descriptions of configurations identical to those in the described example will be omitted.

[0113] like Figure 3 As shown, in the back pressure control valve V2 of this embodiment 2, the side wall 163b of the first segment 163 of the housing 160 has an axially penetrating connecting hole 163c, while the connecting hole of the peripheral wall 163a is omitted. Thus, the communication direction of the connecting hole in the low-pressure space S1 can be appropriately changed. This also applies to the connecting holes communicating with the high-pressure space S2 and the back pressure space S3.

[0114] As described above, if the connecting hole 163c is formed on the side wall 163b, compared to the structure in Embodiment 1 where the connecting hole 63c is formed on the peripheral wall 63a, the second segment 64 can be pressed closer to the side wall 163b when it is pressed into the first segment 63. That is, the axial length of the housing 160 can be adjusted over a wider range. Furthermore, the two O-rings located on the outer periphery of the first segment 163 can be reduced to one.

[0115] While the embodiments of the present invention have been described above with reference to the accompanying drawings, the specific structure is not limited to these embodiments. Any changes or additions made without departing from the spirit of the present invention are also included in the present invention.

[0116] For example, in Embodiments 1 and 2, a structure is described in which the valve body is seated on the valve seat and becomes a closed valve, that is, a structure in which force F1 and force F2 are balanced. However, it is not limited to this. It can also be a structure in which the valve body is not seated on the valve seat, as long as the valve opening degree is variable.

[0117] Further, in the embodiment 1 and the embodiment 2, the structure in which the urging unit is a coil spring is described, but is not limited thereto, and can be a spiral wave spring, can be a plate spring, can be an air spring, and can be appropriately changed. As an example of the air spring, a gas such as nitrogen can be enclosed in the space in the first divided body. That is, as described below, the low-pressure pressure receiving surface on which the suction fluid Ps acts can be omitted.

[0118] Further, in the embodiment 1 and the embodiment 2, the structure in which the urging unit functions as a compression spring is described, but is not limited thereto, and can be a tension spring. If the urging unit is a tension spring, the urging unit can be provided in the back pressure space.

[0119] Further, in the embodiment 1 and the embodiment 2, the structure in which the high-pressure pressure receiving surface is smaller than the back pressure receiving surface is described, but is not limited thereto, and the size relationship between the pressure receiving surfaces can be appropriately changed, and can be the same.

[0120] Further, in the embodiment 1 and the embodiment 2, the structure in which the valve body is provided with the low-pressure pressure receiving surface is described, but is not limited thereto, and the low-pressure pressure receiving surface can be omitted. For example, the structure in which the space in the first divided body is communicated with the atmosphere, and the atmospheric pressure acts on the valve body, or the structure in which the first divided body and the second divided body are omitted, the right end of the second divided body is blocked, and only the pressure of the discharge fluid Pd and the pressure of the control fluid Pb act on the valve body can be used. In the latter structure, the urging unit can be provided in the high-pressure space or the back pressure space.

[0121] Further, in the embodiment 1 and the embodiment 2, the structure in which the sealing unit is an O-ring is described, but is not limited thereto, and can be a lip packing, a gland packing, or the like, and a plurality of the above-described sealing members can be used, and can be appropriately changed.

[0122] Further, in the embodiment 1 and the embodiment 2, the structure in which the relief hole in which the low-pressure chamber and the back pressure chamber are communicated is provided with the throttle hole is described, but is not limited thereto, and a safety valve, a pressure reducing valve, or the like can be provided in the relief hole, and can be appropriately changed.

[0123] Further, in the embodiment 1 and the embodiment 2, the valve for a scroll compressor used in an air conditioning system of an automobile or the like is described, but is not limited thereto, and the valve can be used to control various working fluids.

[0124] Further, in the embodiment 1 and the embodiment 2, the example in which the valve is a back pressure control valve is described, but for example, can be an expansion valve provided between a condenser and an evaporator in an air conditioning system, or a capacity control valve assembled to a variable capacity type compressor in an air conditioning system, or the like.

[0125] Further, the suction fluid, the discharge fluid, the control fluid can be any one of a gas, a liquid, or a mixed state of a gas and a liquid, respectively.

[0126] Symbol explanation 60: housing; 61: valve body; 61d: curved surface (part facing the tapered shape of the passage); 62: coil spring (urging unit); 65a: valve hole (passage); 67: valve seat (tapered shape of the passage); 68: O-ring (sealing unit); 69: stopper; 70: valve; 160: housing; A: effective pressure receiving surface (back pressure pressure receiving surface); B: effective pressure receiving surface (low pressure pressure receiving surface); A-B: effective pressure receiving surface (high pressure pressure receiving surface); C: scroll compressor; Pb: control fluid (back pressure fluid); Pd: discharge fluid (high pressure fluid); Ps: suction fluid (low pressure fluid); S1: low pressure space; S2: high pressure space; S3: back pressure space; V1, V2: back pressure control valve (valve).

Claims

1. A valve, wherein, have: The housing includes a high-pressure space for the inflow of high-pressure fluid, a back-pressure space for the inflow of back-pressure fluid, and a channel disposed between the high-pressure space and the back-pressure space; and Valve body, controlling the opening degree of the channel; as well as The force-applying unit applies force to the valve body in the opening direction. The valve body has: The high-pressure receiving surface bears the pressure of the high-pressure space as a force in the opening direction; as well as The back pressure bearing surface bears the pressure of the back pressure space as a force in the closing direction.

2. The valve according to claim 1, wherein, The back pressure receiving surface is larger than the high pressure receiving surface.

3. The valve according to claim 1 or claim 2, wherein, The housing has a low-pressure space for the inflow of low-pressure fluid. The valve body has a low-pressure receiving surface, which bears the pressure in the low-pressure space as a force in the opening direction.

4. The valve according to claim 3, wherein, A sealing unit is provided between the high-pressure space and the low-pressure space.

5. The valve according to claim 3, wherein, The force-applying unit is configured in the low-pressure space.

6. The valve according to claim 1, wherein, The valve is provided with a stop that restricts the relative movement of the valve body relative to the housing.

7. The valve according to claim 1, wherein, The valve body is configured to block the channel.

8. The valve according to claim 1, wherein, The channel is tapered.

9. The valve according to claim 8, wherein, The portion of the valve body opposite the conical shape of the channel is spherical.

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