Valve

Abstract

The present invention provides a valve that can smoothly change the pressure of a back pressure fluid.　The present invention comprises: 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; a housing 60 that has a passage 65a provided between the high pressure space S2 and the back pressure space S3; a valve body 61 that controls the opening of the passage 65a; and an urging means 62 that urges the valve body 61 in the opening direction. The valve body 61 has a high pressure receiving surface (A-B) that receives the pressure of the high pressure space S2 as a 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

valve

[0001] The present invention relates to valves, for example, valves for controlling pressure.

[0002] Scroll compressors are one type of compressor used in various industrial fields. This type of compressor is not only highly efficient but also quiet, and is therefore used in a wide range of applications, such as refrigeration cycles.

[0003] The scroll compressor is equipped with a scroll compression mechanism consisting of a fixed scroll with a spiral wrap and a movable scroll with a spiral wrap, and an eccentric mechanism attached to a rotating shaft for eccentrically rotating the movable scroll. The movable scroll slides relative to the fixed scroll while rotating eccentrically, thereby pressurizing a fluid refrigerant supplied from low-pressure chambers on the outer diameter sides of both scrolls, and discharging the high-pressure refrigerant from a discharge hole formed in the center of the fixed scroll.

[0004] In this type of scroll compressor, when the pressure in the discharge chamber, from which the refrigerant compressed by the scroll compression mechanism is discharged, increases, a force acts in a direction that separates the movable scroll from the fixed scroll.

[0005] The scroll compressor of Patent Document 1 is provided with a communication passage that connects the discharge chamber with a back pressure chamber formed on the back side of the movable scroll, and the communication passage is provided with an orifice. A portion of the compressed refrigerant in the discharge chamber is decompressed and adjusted by the orifice and supplied to the back pressure chamber, pressing the movable scroll toward the fixed scroll, preventing the movable scroll from separating from the fixed scroll.

[0006] The scroll compressor also has a pressure regulating valve that regulates the pressure in the back pressure chamber by releasing it into the low pressure chamber. When the pressure in the back pressure chamber pushing the valve element in the valve opening direction exceeds the pressure in the low pressure chamber and the biasing force of the spring pushing the valve element in the valve closing direction, the pressure regulating valve opens, allowing refrigerant in 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 pressed against the fixed scroll due to an increase in pressure in the back pressure chamber, which would hinder smooth operation of the movable scroll.

[0007] WO 2022 / 009769 (pages 8 and 9, Figure 1)

[0008] However, in the scroll compressor of Patent Document 1, a portion of the refrigerant in the discharge chamber is supplied at a constant rate to the back pressure chamber through an orifice, which causes a problem that the change in pressure in the back pressure chamber is small relative to the change in pressure in the discharge chamber, and it takes time for the pressure in the back pressure chamber to reach the appropriate pressure.

[0009] The present invention has been made in view of the above-mentioned problems, and has as its object to provide a valve that can smoothly change the pressure of the back pressure fluid.

[0010] In order to solve the above problems, the valve of the present invention 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, a valve body that controls the aperture of the passage, and biasing means that biases the valve body in an opening direction, wherein 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 the closing direction. This ensures an appropriate aperture of the passage at startup and makes the aperture of the passage variable during operation, allowing smooth adjustment of the pressure of the back-pressure fluid.

[0011] The back pressure receiving surface may be wider than the high pressure receiving surface, thereby increasing the effect of the pressure of the back pressure fluid, which is relatively lower than the pressure of the high pressure fluid, and improving responsiveness.

[0012] The housing may have a low-pressure space into which a low-pressure fluid flows, and the valve element may have a low-pressure receiving surface that receives the pressure in the low-pressure space as a force in the opening direction, thereby improving the accuracy of adjusting the pressure of the back-pressure fluid.

[0013] A sealing means may be provided between the high pressure space and the low pressure space, thereby preventing leakage from the high pressure space to the low pressure space inside the valve and preventing a decrease in efficiency.

[0014] The biasing means may be disposed in the low pressure space, which allows the biasing means to be disposed in a manner that does not obstruct the flow of back pressure fluid in the back pressure space.

[0015] The valve may be provided with a stopper that restricts the relative movement of the valve element with respect to the housing. This allows the maximum opening of the passage to be kept substantially constant, thereby enabling the pressure of the back pressure fluid to be adjusted in a short time at start-up.

[0016] The valve element may be arranged to be able to close the passage, thereby reliably preventing an excessive increase in pressure of the back pressure fluid.

[0017] The passage may be tapered, which allows for good flow efficiency even at narrow valve openings.

[0018] The valve element may have a spherical shape at a portion facing the tapered shape of the passage, which makes line contact with the passage in the circumferential direction, thereby achieving both sealing performance and opening / closing response.

[0019] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments and is not to be construed as limiting the invention.

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A valve according to the present invention will be described below with reference to the following examples.

[0021] A valve according to a first embodiment will be described with reference to Figures 1 and 2. The valve of the present invention is applied to a rotary machine including an eccentric mechanism, for example, a scroll compressor C that draws in, compresses, and discharges a refrigerant as a fluid used in an air conditioning system of an automobile, etc. In this embodiment, the refrigerant is a gas mixed with a mist of lubricating oil.

[0022] First, we will explain the scroll compressor C. As shown in Fig. 1 , the scroll compressor C is mainly composed of a housing 1, a rotating shaft 2, an inner casing 3, a scroll compression mechanism 4, a side seal 7, a thrust plate 8, and a drive motor M.

[0023] The housing 1 is composed of a cylindrical casing 11 and a cover 12 that closes an opening of the casing 11. An opening in the casing 11 on the axially opposite side to the opening closed by the cover 12 is closed by a drive motor M.

[0024] The casing 11 is provided with a low-pressure chamber 20 to which low-pressure refrigerant, i.e., intake fluid Ps as a low-pressure fluid, is supplied through the intake port 10 from a refrigerant circuit (not shown), a high-pressure chamber 30 serving as a discharge chamber from which high-pressure refrigerant compressed by the scroll compression mechanism 4, i.e., a discharge fluid Pd as a high-pressure fluid, is discharged, and a back-pressure chamber 50 to which a portion 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, is supplied via a back-pressure control valve V1. The back-pressure chamber 50 is formed inside a cylindrical inner casing 3 housed inside the casing 11.

[0025] A discharge communication passage 13 is formed in the cover 12, connecting a refrigerant circuit (not shown) with the high-pressure chamber 30. A back-pressure communication passage 14 is also formed in the cover 12, connecting the high-pressure chamber 30 with the back-pressure chamber 50, and is branched off from the discharge communication passage 13. An oil separator 6 is provided in the discharge communication passage 13 to separate lubricating oil from the refrigerant.

[0026] The inner casing 3 is fixed with its axial end abutting against an end plate 41a of a fixed scroll 41 that constitutes the scroll compression mechanism 4. A suction communication passage 15 that penetrates radially is formed in the side wall of the inner casing 3. That is, the low-pressure chamber 20 is formed from the outside of the inner casing 3 to the inside of the inner casing 3 via the suction communication passage 15. The suction fluid Ps that is supplied to the inside of the inner casing 3 through the suction communication passage 15 is drawn into the scroll compression mechanism 4.

[0027] The scroll compression mechanism 4 is mainly composed of a fixed scroll 41 that is fixed to the cover 12 in a sealed manner, and a movable scroll 42 that is housed inside the inner casing 3 .

[0028] The fixed scroll 41 is made of metal and has a spiral wrap 41b that protrudes from the surface of a disk-shaped end plate 41a, i.e., the end face of the end plate 41a that faces the movable scroll 42, toward the movable scroll 42. The fixed scroll 41 also has a recess 41c that is recessed in the opposite direction to the cover 12 on the inner diameter side of the back surface of the end plate 41a, i.e., the end face of the end plate 41a that abuts against the cover 12, and this recess 41c and the cover 12 define the high-pressure chamber 30.

[0029] The movable scroll 42 is made of metal and has a spiral wrap 42b that protrudes from the surface of a disk-shaped end plate 42a, i.e., the end face of the end plate 42a that faces the fixed scroll 41, toward the fixed scroll 41. The movable scroll 42 also has a boss 42c that protrudes from the center of the back surface of the end plate 42a. An eccentric portion 2a formed on the rotating shaft 2 is inserted into the boss 42c so as to be rotatable relative to the boss 42c. In this embodiment, the eccentric portion 2a of the rotating shaft 2 and a counterweight portion 2b that protrudes radially outward from the rotating shaft 2 constitute an eccentric mechanism that rotates the rotating shaft 2 eccentrically.

[0030] When the rotary shaft 2 is driven to rotate by the drive motor M, the eccentric portion 2a rotates eccentrically, and the movable scroll 42 slides relative to the fixed scroll 41 while maintaining its posture with the eccentric rotation. At this time, the movable scroll 42 rotates eccentrically relative to the fixed scroll 41, and as this rotation occurs, the contact position of the wraps 41b, 42b moves sequentially in the rotation direction, and the compression chamber 40 formed between the wraps 41b, 42b moves toward the center and gradually shrinks. As a result, the intake fluid Ps sucked into the compression chamber 40 from the low-pressure chamber 20 formed on the outer diameter side of the scroll compression mechanism 4 is compressed, and finally, a high-pressure discharge fluid Pd is discharged into the high-pressure chamber 30 through the discharge hole 41d provided in the center of the fixed scroll 41.

[0031] The side seal 7 is made of resin, has a rectangular cross section, and is annular when viewed in the axial direction, and 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 on the thrust plate 8.

[0032] The thrust plate 8 is made of metal, has an annular shape, and has a seal ring 43 fixed thereto. The seal ring 43 abuts against the inner peripheral end surface of the inner casing 3. As a result, the thrust plate 8 functions as a thrust bearing that receives the axial load of the movable scroll 42 via the side seal 7.

[0033] Additionally, the side seal 7 and the seal ring 43 divide the interior of the inner casing 3 into a low-pressure chamber 20 formed on the outer diameter side of the movable scroll 42 and a back pressure chamber 50 formed on the back surface side of the movable scroll 42. The back pressure chamber 50 is formed as an enclosed space by a seal ring 44 fixed to the inner periphery of a through hole 3 a provided in the center of the inner casing 3, sealing between the back pressure chamber 50 and the rotating shaft 2 inserted through the through hole 3 a.

[0034] A back pressure control valve V1 is provided in a back pressure communication passage 14 that is formed across the cover 12, the fixed scroll 41, and the inner casing 3 and that connects the high pressure chamber 30 and the back pressure chamber 50. In other words, the back pressure control valve V1 is provided inside the housing 1 that is isolated from the outside air.

[0035] A portion of the discharge fluid Pd from the high pressure chamber 30 that is supplied to the back pressure control valve V1 together with the lubricating oil separated by the oil separator 6 is adjusted in pressure to a control fluid Pb and is supplied to the back pressure chamber 50.

[0036] The inner casing 3 is formed with a pressure relief hole 16 that penetrates radially and connects the low pressure chamber 20 and the back pressure chamber 50 , and an orifice 45 is provided within the pressure relief hole 16 .

[0037] Next, the back pressure control valve V1 as a valve in this embodiment will be described with reference to Fig. 2. In the following description, the left and right sides as viewed from the front side of Fig. 2 will be referred to as the left and right sides of the back pressure control valve V1.

[0038] As shown in FIG. 2, the back pressure control valve V1 of the first embodiment is mainly composed of a housing 60, a valve element 61, and a coil spring 62 as a biasing means for biasing the valve element 61 in the direction in which it leaves its seat, i.e., in the direction in which the valve is opened.

[0039] The housing 60 defines a low pressure space S1 communicating with the low pressure chamber 20, a high pressure space S2 communicating with the high pressure chamber 30, and a back pressure space S3 communicating with the back pressure chamber 50. The housing 60 also defines a valve hole 65a as a passage connecting the high pressure space S2 and the back pressure space S3, and a through hole 64a connecting the low pressure space S1 and the high pressure space S2. It is sufficient that the housing 60 defines at least a portion of the low pressure space S1, the high pressure space S2, and the back pressure space S3.

[0040] The housing 60 is composed of a first divided body 63, a second divided body 64, and a third divided body 65, in that order from the right side.

[0041] The first divided body 63 has a peripheral wall 63a and a side wall 63b, and is formed in a cylindrical shape with a side wall that is open toward the left in the axial direction.

[0042] The inner surface of the peripheral wall 63a is formed in a cylindrical shape extending in the axial direction. The peripheral wall 63a is provided with communication holes 63c that penetrate radially and communicate with the low pressure chamber 20. In this embodiment, there are two equally spaced communication holes 63c, but the number and arrangement of the communication holes 63c may be changed as appropriate.

[0043] The inner diameter of the peripheral wall 63a is substantially constant along the axial direction.

[0044] The side wall 63b is formed in a disk shape that closes the right end of the peripheral wall 63a in the axial direction.

[0045] The side wall 63b has a cylindrical protrusion 63d that protrudes axially leftward from the center of its left end face. The right axial end of the coil spring 62 is fitted onto the protrusion 63d. This positions the right axial end of the coil spring 62 in the radial direction. The right axial end of the coil spring 62 abuts against the side wall 63b.

[0046] The second divided body 64 is formed in an axially extending cylindrical shape and includes, in order from the left in the axial direction, a large inner diameter peripheral wall 64b, a medium inner diameter peripheral wall 64c, and a small inner diameter peripheral wall 64d. The large inner diameter peripheral wall 64b, the medium inner diameter peripheral wall 64c, and the small inner diameter peripheral wall 64d have substantially the same outer circumferential surface. Hereinafter, these will be simply referred to as the outer circumferential surface of the second divided body 64.

[0047] The outer diameter of the second divided body 64 is substantially constant along the axial direction and is substantially the same as or slightly larger than the inner diameter of the peripheral wall 63 a of the first divided body 63 .

[0048] The large inner diameter peripheral wall 64b has a cylindrical shape extending in the axial direction. The large inner diameter peripheral wall 64b has communication holes 64e formed therein that penetrate radially and communicate with the high-pressure space S2. In this embodiment, the communication holes 64e are equally spaced, but the number and arrangement of the communication holes 64e may be changed as appropriate.

[0049] The outer diameter end of the communication hole 64e is an annular recess 64f that is expanded in diameter and opens toward the outer diameter side, and communicates with the high-pressure chamber 30. A filter 66 is provided in the recess 64f to remove foreign matter such as contaminants contained in the refrigerant.

[0050] The middle inner diameter peripheral wall 64c is cylindrical and extends axially rightward from the right end of the large inner diameter peripheral wall 64b. The middle inner diameter peripheral wall 64c has an inner diameter smaller than the inner diameter of the large inner diameter peripheral wall 64b.

[0051] The small inner diameter peripheral wall 64d is cylindrical and extends axially rightward from the right end of the medium inner diameter peripheral wall 64c. The inner diameter of the small inner diameter peripheral wall 64d is smaller than the inner diameter of the medium inner diameter peripheral wall 64c.

[0052] A through-hole 64a is formed in the radial center of the small inner diameter peripheral wall 64d, penetrating in the axial direction.

[0053] The right end of the second division body 64 is press-fitted and fixed inside the peripheral wall 63a of the first division body 63. The space surrounded by the peripheral wall 63a and side wall 63b of the first division body 63 and the small inner diameter peripheral wall 64d of the second division body 64 forms a low-pressure space S1 into which the intake fluid Ps flows.

[0054] The third divided body 65 is formed in a cylindrical shape with an outer step and includes, in order from the left in the axial direction, a large outer diameter peripheral wall 65b and a small outer diameter peripheral wall 65c.

[0055] The large outer diameter peripheral wall 65b is cylindrical and extends in the axial direction.

[0056] The small outer diameter peripheral wall 65c is cylindrical and extends axially rightward from the right end of the large outer diameter peripheral wall 65b. The small outer diameter peripheral wall 65c has a smaller outer diameter than the large outer diameter peripheral wall 65b.

[0057] The outer diameter of the small outer diameter peripheral wall 65c is substantially constant along the axial direction, and is substantially the same as or slightly larger than the inner diameter of the large inner diameter peripheral wall 64b of the second divided body 64.

[0058] A valve hole 65a is provided at the radial center of the large outer diameter peripheral wall 65b and the small outer diameter peripheral wall 65c, i.e., the radial center of the third divided body 65, penetrating in the axial direction and communicating with the high pressure space S2 and the back pressure space S3.

[0059] A tapered surface is formed on the inner diameter side of the large outer diameter peripheral wall 65b, widening the diameter of the valve hole 65a toward the left. This tapered surface serves as a valve seat 67 with which the large diameter body portion 61a of the valve element 61 comes into contact and separates. In other words, the large diameter body portion 61a and the valve seat 67 form a valve 70 that controls the flow rate and the opening and closing of the flow path by the contact and separation of the housing 60 and the valve element 61.

[0060] A back pressure space S3 is formed at the left end of the inner diameter side of the large outer diameter peripheral wall 65b, which is in communication with the back pressure chamber 50. The back pressure space S3 is recessed axially to the right of the left end face of the large outer diameter peripheral wall 65b, is in communication with the valve hole 65a, and is open axially leftward.

[0061] The third divider 65 is fixed by press-fitting its small outer diameter peripheral wall 65c into the large inner diameter peripheral wall 64b of the second divider 64. The third divider 65 is also positioned in the axial direction by its large outer diameter peripheral wall 65b abutting against the large inner diameter peripheral wall 64b of the second divider 64. The space surrounded by the large inner diameter peripheral wall 64b, the medium inner diameter peripheral wall 64c, and the small inner diameter peripheral wall 64d of the second divider 64 and the third divider 65 forms a high-pressure space S2 into which the discharge fluid Pd flows.

[0062] The valve body 61 is formed in a stepped cylindrical shape and includes, in order from the left in the axial direction, a large diameter body portion 61a, a small diameter body portion 61b, and a medium diameter body portion 61c.

[0063] The large-diameter body portion 61a has a curved surface 61d that is formed as part of a spherical shape and whose diameter decreases from its left end toward the right in the axial direction.

[0064] The large-diameter body 61a is disposed across the high-pressure space S2 on the axial right side of the valve seat 67 and the back-pressure space S3 on the axial left side 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 body 61a.

[0065] The small diameter body portion 61b is formed in a cylindrical shape extending axially rightward from the right end of the large diameter body portion 61a. The diameter of the small diameter body portion 61b is approximately the same as the minimum diameter of the large diameter body portion 61a.

[0066] The small diameter body portion 61b is inserted into the valve hole 65a.

[0067] The medium-diameter body portion 61c is formed in a cylindrical shape that expands in diameter from the right end of the small-diameter body portion 61b toward the right in the axial direction, extends toward the right in the axial direction with approximately the same diameter, and then contracts in diameter toward the right in the axial direction. 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. The minimum diameter of the medium-diameter body portion 61c is approximately the same as the diameter of the small-diameter body portion 61b.

[0068] The medium diameter body 61c is inserted into the through hole 64a and is 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 suction fluid Ps act on the medium diameter body 61c.

[0069] An O-ring 68 serving as a sealing means is fitted onto the outside of the medium-diameter body portion 61c at the axial center thereof. The O-ring 68 is fitted onto the inside of the medium-inner-diameter peripheral wall 64c of the second divided body 64. The O-ring 68 seals the gap 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.

[0070] Furthermore, the small inner diameter peripheral wall 64d continues axially to the right of the medium inner diameter peripheral wall 64c, i.e., on the low-pressure space S1 side. In other words, the O-ring 68 seals the space between the low-pressure space S1 and the high-pressure space S2. Furthermore, because the O-ring 68 abuts against the small inner diameter peripheral wall 64d, even if it receives a force that would move it axially to the right due to 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, the O-ring 68 is prevented from moving.

[0071] The right axial end of the medium diameter body portion 61c is press-fitted into and fixed to a stopper 69. The stopper 69 is formed in an annular shape. The inner diameter of the stopper 69 is approximately the same as or slightly smaller than the outer diameter of the medium diameter body portion 61c.

[0072] The right end of the medium diameter body portion 61c protrudes axially to the right beyond the right axial edge of the stopper 69, and the left axial end of the coil spring 62 is extrapolated thereto. This determines the radial position of the left axial end of the coil spring 62. The left axial end of the coil spring 62 also abuts against the stopper 69.

[0073] As described above, the pressures of the control fluid Pb and the discharge fluid Pd act on the large diameter body portion 61a of the valve body 61, and the pressures of the discharge fluid Pd and the suction fluid Ps act on the medium diameter body portion 61c.

[0074] The effective pressure receiving surface of the valve element 61 as a back pressure receiving surface on which the pressure of the control fluid Pb acts is substantially the same as the flow path cross section A of the valve seat 67 at the point where the large diameter body portion 61a is in line contact with the valve seat 67 in the circumferential direction when seated on the valve seat 67. Hereinafter, the effective pressure receiving surface of the valve element 61 on which the pressure of the control fluid Pb acts will be referred to as the "effective pressure receiving surface A."

[0075] The effective pressure receiving surface of the valve body 61 as the high-pressure pressure receiving surface on which the pressure of the discharge fluid Pd acts is substantially the same as the portion located on the outer diameter side of the cross section B of the medium diameter body portion 61c within the flow path cross section A of the valve seat 67 at the point where the large diameter body portion 61a is in line contact in the circumferential direction when seated on the valve seat 67. Hereinafter, the effective pressure receiving surface of the valve body 61 on which the pressure of the discharge fluid Pd acts will be referred to as the "effective pressure receiving surface (A-B)."

[0076] In other words, 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 (AB) of the valve body 61 on which the pressure of the discharge fluid Pd acts (A>(AB)).

[0077] The effective pressure-receiving surface of the valve body 61, which is the low-pressure pressure-receiving surface on which the pressure of the intake fluid Ps acts, is substantially identical to the cross section B of the medium-diameter body portion 61c. Hereinafter, the effective pressure-receiving surface of the valve body 61 on which the pressure of the intake fluid Ps acts will be referred to as the "effective pressure-receiving surface B."

[0078] 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.

[0079] The valve body 61 is responsive to the force (F Ｐｓ = Ps × B) and the force (F Ｐｄ = Pd × (A - B)) and the biasing force of the coil spring 62 (F ｂ ) is pushed to the left in the axial direction (i.e., the leftward direction is positive, and the valve body 61 is pressed by a force F １ =F Ｐｓ +F Ｐｄ +F ｂ is at work).

[0080] The valve body 61 also receives a force (F Ｐｂ = Pb × A) is applied to the valve body 61 in the axial direction to the right (i.e., the rightward direction is positive, and the valve body 61 is pressed by a force F ２ =F Ｐｂ is at work).

[0081] The valve body 61 is subjected to a force F １ The force F ２ When the force F １ >Force F ２ ). The stopper 69 abuts against the small inner diameter peripheral wall 64d of the second divided body 64 of the housing 60, thereby restricting movement to the left in the axial direction. In this state, the opening of the valve 70 is at its maximum. More specifically, it is preferable that the opening be larger than that of the fixed orifice in Patent Document 1.

[0082] In this embodiment, the biasing force of the coil spring 62 (F ｂ ) and the effective pressure receiving surfaces A and B are adjusted so that the opening of the valve 70 is maximized when the pressures of the intake fluid Ps, discharge fluid Pd, and control fluid Pb are approximately the same. In other words, the back pressure control valve V1 is a normally open type.

[0083] More specifically, when the scroll compressor C is stopped for a long period of time, the pressures of the intake fluid Ps, the discharge fluid Pd, and the control fluid Pb may become equilibrium and become substantially the same.

[0084] In this case, when the scroll compressor C is started, the pressure of the discharge fluid Pd increases slightly, while the pressure of the suction fluid Ps decreases slightly. At this time, the pressure of the suction fluid Ps is higher than the pressure range of the suction fluid Ps during normal continuous operation, and the opening of the valve 70 remains at its maximum.

[0085] As a result, a large amount of the discharge fluid Pd passes through the valve 70 and is supplied to the back pressure chamber 50, so that the pressure of the control fluid Pb can be increased immediately.

[0086] Thereafter, as the operation of the scroll compressor C continues, the force F acting on the valve body 61 １ and force F ２ The difference between the force F and the force F decreases. １ and force F ２ When this balance is reached, the valve element 61 seats on the valve seat 67. That is, the opening of the valve 70 mainly changes within a range from an opening larger than that of the fixed orifice of Patent Document 1 to a range in which the valve 70 is closed.

[0087] As described above, the back pressure control valve V1 of this embodiment is of a normally open type, and since the opening degree of the valve hole 65a is properly ensured when the scroll compressor C is started up, the pressure of the control fluid Pb can be smoothly adjusted. Furthermore, since the back pressure control valve V1 is of a normally open type and is unlikely to suffer from a shortage of back pressure, it is easy to favorably control the compression efficiency of the scroll compression mechanism 4 even when the scroll compressor C is started up.

[0088] Furthermore, since the back pressure control valve V1 can change the opening degree of the valve hole 65a while the scroll compressor C is in operation, the pressure of the control fluid Pb can be smoothly adjusted.

[0089] Furthermore, 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 lower than the pressure of the discharge fluid Pd, can be increased, thereby improving responsiveness.

[0090] Furthermore, the valve body 61 has an effective pressure-receiving surface B on which the pressure of the intake fluid Ps acts, improving the accuracy of adjusting the pressure of the control fluid Pb.

[0091] Furthermore, the back pressure control valve V1 seals the high pressure space S2 and the low pressure space S1 with an O-ring 68, preventing the discharge fluid Pd that has flowed into the high pressure space S2 from leaking into the low pressure space S1, thereby preventing leakage inside the valve and reducing efficiency.

[0092] Furthermore, since the coil spring 62 is disposed in the low pressure space S1, it is less likely to obstruct the flow of the control fluid in the back pressure space S3.

[0093] Furthermore, since the back pressure control valve V1 is provided with a stopper 69, the maximum opening degree of the valve hole 65a can be kept substantially constant, which allows the pressure of the control fluid Pb to be adjusted in a short time when the scroll compressor C is started up.

[0094] Furthermore, since the valve element 61 is arranged so as to be able to close the valve hole 65a, an excessive increase in pressure of the control fluid Pb can be reliably prevented.

[0095] Furthermore, the valve seat 67 in the valve hole 65a has a tapered shape, so that the flow efficiency is good even when the valve opening is narrow.

[0096] Furthermore, since the valve body 61 has a curved surface 61d facing the valve seat 67, when it seats on the valve seat 67 it makes line contact in the circumferential direction, thereby achieving both sealing performance and opening / closing response.

[0097] In addition, the housing 60 has the second division 64 press-fitted into the first division 63, and the amount of press-fitting can be varied within the range of the press-fitting allowance, so not only can the spring force of the coil spring 62 be adjusted, but the axial length of the housing 60 can also be adjusted.

[0098] Furthermore, the valve body 61 is press-fitted and fixed into the stopper 69, and the amount of press-fitting can be varied within the range of the press-fitting allowance, so that the stroke amount of the valve body 61, in other words, the maximum opening degree of the valve 70, can be adjusted.

[0099] Furthermore, when the valve 70 is at its maximum opening, the stopper 69 comes into contact with the second divided body 64 of the housing 60, sealing the gap between the stopper 69 and the second divided body 64. This not only makes it difficult for the discharge fluid Pd to leak from the high-pressure space S2 to the low-pressure space S1, but also ensures an effective pressure-receiving surface that is larger than the effective pressure-receiving surface B, making it easier to maintain the maximum opening of the valve 70.

[0100] Furthermore, the valve element 61 is aligned along the axis of the second divided body 64 by the elastic force of the O-ring 68. This reduces the likelihood of sliding contact between the outer peripheral surface of the small-diameter body portion 61b and the inner peripheral surface of the valve hole 65a when the valve element 61 moves in the axial direction, making it easier to reduce the frictional force that occurs.

[0101] Next, a valve according to a second embodiment will be described with reference to Fig. 3. Note that a description of the same configuration as in the previous embodiment will be omitted.

[0102] 3, in the back pressure control valve V2 of the second embodiment, a communication hole 163c is formed in the side wall 163b of the first divided body 163 of the housing 160, penetrating in the axial direction, while no communication hole is formed in the peripheral wall 163a. ​​In this manner, the communication direction of the communication hole with respect to the low pressure space S1 may be changed as appropriate. The same applies to the communication hole communicating with the high pressure space S2 and the communication hole communicating with the back pressure space S3.

[0103] As described above, when the communication hole 163c is formed in the side wall 163b, the second divided body 64 can be brought closer to the side wall 163b when press-fitting into the first divided body 63, compared to the configuration in which the communication hole 63c is formed in the peripheral wall 63a in the first embodiment. In other words, the axial length of the housing 160 can be adjusted over a wider range. Also, the number of O-rings provided on the outer periphery of the first divided body 163 can be reduced to one.

[0104] 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.

[0105] For example, in the first and second embodiments, the valve element is seated on the valve seat to close the valve, i.e., the force F １ and force F ２ However, the present invention is not limited to this, and the valve body may not be seated on the valve seat, and it is sufficient that the valve opening degree is variable.

[0106] In addition, in the first and second embodiments, the biasing means is described as a coil spring, but the biasing means is not limited to this and may be a coiled wave spring, a leaf spring, an air spring, or any other suitable configuration. As an example of an air spring, a gas such as nitrogen may be sealed in the space within the first divided body. In other words, as described below, the low-pressure receiving surface on which the intake fluid Ps acts may be omitted.

[0107] In addition, in the first and second embodiments, the biasing means functions as a compression spring, but is not limited to this and may be an extension spring. If the biasing means is an extension spring, the biasing means may be disposed in the back pressure space.

[0108] Furthermore, in the above-described first and second embodiments, the high-pressure receiving surface is smaller than the back-pressure receiving surface, but this is not limited to this, and the size relationship between the pressure receiving surfaces may be changed as appropriate, or may be the same.

[0109] In addition, in the first and second embodiments, the valve element is described as having a low-pressure receiving surface, but this is not limited thereto, and the low-pressure receiving surface may be omitted. For example, the space within the first divided body may be connected to the atmosphere, so that atmospheric pressure acts on the valve element, or the first divided body may be omitted, and the right end of the second divided body may be closed, so that only the pressure of the discharge fluid Pd and the pressure of the control fluid Pb act on the valve element. In the latter configuration, the biasing means may be disposed in the high-pressure space or the back-pressure space.

[0110] Furthermore, in the first and second embodiments, the sealing means is described as an O-ring, but this is not limited to this, and any other means may be used, such as a lip packing or a gland packing, as long as it is capable of sealing between the high-pressure space and the low-pressure space. Multiple sealing members such as those described above may be applied, and may be changed as appropriate.

[0111] In addition, in the first and second embodiments, an orifice is provided in the pressure relief hole that connects the low pressure chamber and the back pressure chamber. However, this is not limited to this, and a relief valve or a pressure reducing valve may be provided in the pressure relief hole, and other modifications may be made as appropriate.

[0112] Furthermore, in the first and second embodiments, the valve is applied to a scroll compressor used in an air conditioning system of an automobile or the like, but the present invention is not limited to this, and the valve may be used to control various working fluids.

[0113] In addition, in the first and second embodiments, the valve is a back pressure control valve. However, the valve may 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.

[0114] The intake fluid, discharge fluid, and control fluid may each be in the form of gas, liquid, or a mixture of gas and liquid.

[0115] 60 Housing 61 Valve body 61d Curved surface (portion facing the tapered shape of the passage) 62 Coil spring (biasing means) 65a Valve hole (passage) 67 Valve seat (tapered shape of the passage) 68 O-ring (sealing means) 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 comprising: 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; a valve body which controls the opening degree of the passage; and a biasing means which biases the valve body in an opening direction, wherein the valve body has a high pressure pressure receiving surface which receives the pressure of the high pressure space as a force in the opening direction, and a back pressure pressure receiving surface which receives the pressure of the back pressure space as a force in the closing direction.

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

3. A valve as claimed in claim 1 or 2, wherein the housing has a low pressure space into which low pressure fluid flows, and the valve body has a low pressure receiving surface which receives the pressure within the low pressure space as a force in the opening direction.

4. A valve as claimed in claim 3, further comprising sealing means between said high pressure space and said low pressure space.

5. The valve according to claim 3, wherein said biasing means is disposed in said low pressure space.

6. The valve according to claim 1, wherein said valve is provided with a stopper for restricting relative movement of said valve element with respect to said housing.

7. The valve according to claim 1, wherein said valve element is arranged so as to be capable of closing said passage.

8. The valve of claim 1, wherein said passage is tapered.

9. The valve according to claim 8, wherein the valve element has a spherical shape at a portion facing the tapered shape of the passage.

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