Pressure differential valve and valve device having the same

Abstract

A differential pressure valve capable of suppressing diaphragm damage caused by foreign objects and a valve device having the differential pressure valve are provided. The valve body (10) of the solenoid valve (1) has a main valve chamber (12), a first outlet (14) connected to the main valve chamber (12) via a main valve seat (17), a differential pressure valve chamber (13) connected to the main valve chamber (12) via a branch passage (18), and a second outlet (15) connected to the differential pressure valve chamber (13) via a differential pressure valve seat (20). The solenoid valve (1) has a diaphragm (51) made of synthetic resin that divides the differential pressure valve chamber (13) and the first outlet (14) within the valve body (10), and an annular retaining member (54) fixed relative to the valve body (10). An annular protective sheet (52) made of synthetic resin is disposed overlapping the surface of the retaining member (54) in the outer periphery (51b) of the diaphragm (51). The outer periphery (51b) of the diaphragm (51) and the protective plate (52) are held between the valve body (10) and the retaining member (54).

Description

Technical Field

[0001] This invention relates to a differential pressure valve and a valve device having the differential pressure valve. Background Technology

[0002] Patent Document 1 discloses a solenoid valve with a differential pressure valve as an example of a conventional valve device. The solenoid valve in Patent Document 1 has a solenoid valve section and a differential pressure valve section within a valve body. The valve body has a main valve chamber, a differential pressure valve chamber, an inlet, a first outlet, and a second outlet. The inlet is connected to the main valve chamber. The main valve chamber is connected to the first outlet via a main valve seat. The main valve chamber is also connected to the differential pressure valve chamber via a branch passage. The differential pressure valve chamber is connected to the second outlet via a differential pressure valve seat. The solenoid valve section has a main valve core that opens and closes the main valve seat. The differential pressure valve section has a differential pressure valve core that opens and closes the differential pressure valve seat.

[0003] The differential pressure valve core is mounted on a diaphragm made of synthetic resin. The diaphragm divides the differential pressure chamber and the first outlet, which serves as the back pressure chamber. The outer periphery of the diaphragm is held between the valve body and a cylindrical retaining member. The retaining member has an inner circumferential surface and an annular plane that contacts the diaphragm; the annular plane and the inner circumferential surface are smoothly connected by a curved connecting surface. In a solenoid valve, the diaphragm deforms along the connecting surface, thus preventing the deformation from concentrating in one area. When the diaphragm deforms due to the pressure difference between the differential pressure chamber and the first outlet, the differential pressure valve core moves to open and close the differential pressure valve seat.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-152848

[0007] The technical problem that the invention aims to solve

[0008] The aforementioned solenoid valves are used, for example, in heat pump systems. The refrigerant in heat pump systems sometimes contains foreign matter such as metal powder generated by the operation of the solenoid valve and pump. When the diaphragm deforms, this foreign matter may become trapped between the diaphragm and the retaining components, potentially causing diaphragm damage. Summary of the Invention

[0009] Therefore, the object of the present invention is to provide a differential pressure valve capable of suppressing damage to the diaphragm caused by foreign matter, and a valve device having the differential pressure valve.

[0010] Technical means for solving technical problems

[0011] To achieve the above objectives, one aspect of the present invention relates to a differential pressure valve comprising: a valve body having a valve chamber and a back pressure chamber; a diaphragm made of synthetic resin configured to divide the valve chamber and the back pressure chamber; an annular retaining member fixed relative to the valve body; and a valve core disposed in the valve chamber and movable via the diaphragm. The differential pressure valve also includes an annular protective plate made of synthetic resin configured to contact one side of the outer periphery of the diaphragm, the outer periphery of the diaphragm and the protective plate being held between the valve body and the retaining member.

[0012] According to the present invention, the differential pressure valve has a ring-shaped protective plate made of synthetic resin, which is configured to contact one side of the outer periphery of the diaphragm. Furthermore, the outer periphery of the diaphragm and the protective plate are held between the valve body and the retaining member. Thus, when the diaphragm deforms, foreign objects are trapped between the valve body or the retaining member and the protective plate, preventing direct contact between foreign objects and the diaphragm. Therefore, damage to the diaphragm can be suppressed in the differential pressure valve.

[0013] In this invention, preferably, when there is no pressure difference between the valve chamber and the back pressure chamber, the central portion of the diaphragm is truncated cone-shaped, and the valve core is mounted on the central portion of the diaphragm. This increases the range of movement of the valve core.

[0014] In this invention, it is preferable that the inner diameter of the protective sheet is smaller than the outer diameter of the central portion of the diaphragm. This allows the deformable portion of the diaphragm to be different during valve opening and closing, thereby improving the durability of the diaphragm.

[0015] In this invention, preferably, the protective sheet is configured to contact the surface of the retaining member on the outer periphery of the diaphragm. The retaining member has: an annular plane that contacts the protective sheet, a cylindrical inner circumferential surface, and a curved connecting surface that smoothly connects the annular plane and the inner circumferential surface. The inner diameter of the protective sheet is smaller than the diameter of the inner circumferential surface of the retaining member. In this way, the protective sheet is configured to be entirely opposite the connecting surface, thereby more reliably preventing foreign objects from being trapped between the diaphragm and the connecting surface, and further suppressing damage to the diaphragm.

[0016] In this invention, preferably, the differential pressure valve further comprises an annular sealing member configured to contact the other side of the outer periphery of the diaphragm. The sealing member, the outer periphery of the diaphragm, and the protective plate are held between the valve body and the retaining member. This allows for effective sealing between the valve chamber and the back pressure chamber.

[0017] To achieve the above objectives, another aspect of the present invention relates to a valve device comprising: a valve body having an inlet, a main valve chamber connected to the inlet, a first outlet connected to the main valve chamber via a main valve seat, a differential pressure valve chamber connected to the main valve chamber via a branch passage, and a second outlet connected to the differential pressure valve chamber via a differential pressure valve seat; a main valve core disposed in the main valve chamber for opening and closing the main valve seat; a diaphragm made of synthetic resin configured to divide the differential pressure valve chamber and the first outlet as a back pressure chamber; an annular retaining member fixed relative to the valve body; and a differential pressure valve core disposed in the differential pressure valve chamber and movable via the diaphragm. The valve device has an annular protective sheet made of synthetic resin configured to contact one side of the outer periphery of the diaphragm, the outer periphery of the diaphragm and the protective sheet being held between the valve body and the retaining member.

[0018] According to the present invention, the valve device has a ring-shaped protective sheet made of synthetic resin, which is configured to contact one side of the outer periphery of the diaphragm. Furthermore, the outer periphery of the diaphragm and the protective sheet are held between the valve body and the retaining member. Thus, when the diaphragm deforms, foreign objects are trapped between the valve body or retaining member and the protective sheet, preventing direct contact between foreign objects and the diaphragm. Therefore, damage to the diaphragm can be suppressed in the valve device.

[0019] Invention Effects

[0020] According to the present invention, damage to the diaphragm caused by foreign objects can be suppressed. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of a solenoid valve with a differential pressure valve according to an embodiment of the present invention.

[0022] Figure 2 yes Figure 1 An enlarged cross-sectional view (closed state) of the differential pressure valve section of a solenoid valve with a differential pressure valve.

[0023] Figure 3 yes Figure 2 An enlarged sectional view of the part enclosed by a circle with a single-dot dashed line.

[0024] Figure 4 yes Figure 1 An enlarged cross-sectional view (open state) of the differential pressure valve section of a solenoid valve with a differential pressure valve.

[0025] Figure 5 yes Figure 4 An enlarged sectional view of the part enclosed by a circle with a single-dot dashed line. Detailed Implementation

[0026] The following is for reference Figures 1-5 An embodiment of the valve device of the present invention will be described, which relates to a solenoid valve with a differential pressure valve.

[0027] Figure 1 This is a cross-sectional view of a solenoid valve with a differential pressure valve according to an embodiment of the present invention. Figure 2 yes Figure 1 An enlarged cross-sectional view of the differential pressure valve section of a solenoid valve with a differential pressure valve. Figure 2 Differential pressure valve section indicating the closed valve state. Figure 3 yes Figure 2 An enlarged sectional view of the part enclosed by a circle with a single-dot dashed line. Figure 4 yes Figure 1 An enlarged cross-sectional view of the differential pressure valve section of a solenoid valve with a differential pressure valve. Figure 4 Differential pressure valve section indicating the open valve state. Figure 5 yes Figure 4 An enlarged sectional view of the area enclosed by a circle with a single-dotted line. In the following description, the terms "up, down, left, and right" indicate the relative positional relationships of the constituent elements shown in each drawing.

[0028] like Figures 1-5 As shown, the solenoid valve 1 with a differential pressure valve (hereinafter simply referred to as "solenoid valve 1") of this embodiment has a valve body 10. A solenoid valve section 30 and a differential pressure valve section 50 are provided in the valve body 10.

[0029] The valve body 10 has a generally rectangular parallelepiped shape. The valve body 10 has an inlet 11, a main valve chamber 12, a differential pressure valve chamber 13, a first outlet 14, and a second outlet 15.

[0030] The inlet 11 opens on the left side 10a of the valve body 10. The inlet 11 is connected to the main valve chamber 12. A circular main valve seat 17 surrounding the main valve port 16 is disposed in the main valve chamber 12. The main valve chamber 12 is connected to the first outlet 14 via the main valve seat 17 and the main valve port 16. The first outlet 14 opens on the left side 10a of the valve body 10. The main valve chamber 12 is also connected to the differential pressure valve chamber 13 via a branch passage 18. A circular differential pressure valve seat 20 surrounding the differential pressure valve port 19 is disposed in the differential pressure valve chamber 13. The differential pressure valve chamber 13 is connected to the second outlet 15 via the differential pressure valve seat 20 and the differential pressure valve port 19. The second outlet 15 opens on the back side of the valve body 10.

[0031] The solenoid valve section 30 includes an attraction member 31 serving as a fixed iron core, a housing 32, a plunger 33, a solenoid coil 34, a valve shaft 35, a pilot valve core 36, and a main valve core 40.

[0032] The suction member 31 integrally comprises a large-diameter cylindrical portion 31a and a small-diameter cylindrical portion 31b continuously disposed at the upper end of the large-diameter cylindrical portion 31a. The large-diameter cylindrical portion 31a is fixed to the valve body 10 by a threaded structure. The small-diameter cylindrical portion 31b is configured to extend upward from the valve body 10.

[0033] The housing 32 has a cylindrical shape with its upper end blocked. A small-diameter cylindrical portion 31b of a suction member 31 is inserted into the lower end of the housing 32. The housing 32 engages with the suction member 31.

[0034] The plunger 33 has a cylindrical shape and an outer diameter slightly smaller than the inner diameter of the housing 32. The plunger 33 is configured inside the housing 32 to be movable in the vertical direction. An opening spring 38 is disposed between the plunger 33 and the small-diameter cylindrical portion 31b of the suction member 31. The opening spring 38 is a compression coil spring and pushes the plunger 33 upwards.

[0035] The electromagnetic coil 34 is cylindrical in shape and has an inner diameter slightly larger than the outer diameter of the housing 32. The housing 32 is inserted inside the electromagnetic coil 34. The electromagnetic force of the electromagnetic coil 34 magnetizes the attracting member 31 and the plunger 33. The electromagnetic coil 34 is positioned outside the housing 32.

[0036] The valve shaft 35 has an elongated cylindrical shape. The upper end of the valve shaft 35 is fixed to the plunger 33. The valve shaft 35 is inserted into the small-diameter cylindrical portion 31b of the suction member 31. The valve shaft 35 is supported by the small-diameter cylindrical portion 31b so that it can move in the vertical direction. The valve shaft 35 has a fluid passage 35a extending from the upper end to near the lower end.

[0037] The pilot valve core 36 is continuously connected to the lower end of the valve shaft 35. A circular plate-shaped gasket 36a is installed on the lower surface of the pilot valve core 36.

[0038] The main valve core 40 integrally comprises a cylindrical body 41, an upper flange 42 disposed on the upper part of the body 41, and a lower flange 43 disposed on the lower part of the body 41. The body 41 has a pilot valve port 44 extending from the upper end to the lower end. A pilot valve seat 45 surrounding the pilot valve port 44 is disposed at the upper end of the body 41. The upper flange 42 is configured to slide vertically inside the large-diameter cylindrical portion 31a of the suction member 31. The upper flange 42 divides the main valve chamber 12 and the pilot valve chamber 37 inside the suction member 31. The upper flange 42 has a pressure equalization passage 42a connecting the main valve chamber 12 and the pilot valve chamber 37. A ring-shaped gasket 43a is mounted on the lower surface of the lower flange 43. The outer diameter of the lower flange 43 is smaller than the outer diameter of the upper flange 42. An opening spring 39 is disposed between the upper flange 42 of the main valve core 40 and the valve body 10. The opening spring 39 is a compression helical spring and pushes the main valve core 40 upward.

[0039] The solenoid valve section 30 is a normally open solenoid valve that is in the open state when the solenoid coil 34 is not energized. The solenoid valve section 30 can also be a normally closed solenoid valve that is in the closed state when the solenoid coil 34 is not energized.

[0040] The differential pressure valve section 50 includes a diaphragm 51, a protective plate 52, a sealing component 53, a retaining component 54, a differential pressure valve frame 55, a differential pressure valve core 56, and a stop component 57.

[0041] The diaphragm 51 is, for example, a thin film made of a synthetic resin such as polyimide. The diaphragm 51 divides the valve body 10 into a differential pressure chamber 13 and a first outlet 14, which serves as a back pressure chamber. The diaphragm 51 integrally has a central portion 51a and an outer peripheral portion 51b. The central portion 51a, in the absence of a pressure difference between the differential pressure chamber 13 and the first outlet 14, is a frustum-shaped cone protruding towards the differential pressure chamber 13. The outer peripheral portion 51b has an annular shape. The inner peripheral edge of the outer peripheral portion 51b is continuously disposed with the outer peripheral edge of the central portion 51a. Figure 3 In the diagram, arrow A indicates the boundary between the central portion 51a and the outer peripheral portion 51b. Furthermore, the truncated cone shape in this specification includes, for example, a shape where the central portion is a gently bulging dome, and the outer perimeter and ceiling portion are connected by smooth curved surfaces; and a shape where the outer perimeter and ceiling portion are formed by smooth curved surfaces.

[0042] The protective sheet 52 is, for example, a thin film made of a synthetic resin such as polyimide. The protective sheet 52 has a circular shape. The outer diameter of the protective sheet 52 is the same as the outer diameter of the diaphragm 51. The inner diameter of the protective sheet 52 is slightly smaller than the outer diameter of the central portion 51a of the diaphragm 51. By setting the inner diameter of the protective sheet 52 to be smaller than the outer diameter of the central portion 51a, the deformation portion of the diaphragm can be different during valve opening and valve closing. Therefore, the durability of the diaphragm 51 can be improved. The inner diameter of the protective sheet 52 is preferably smaller than... Figure 3The contact area (contact surface) between the diaphragm 51 and the stop 57 in the closed valve state is large, so that the inner periphery of the protective plate 52 is not trapped between the stop 57 and the diaphragm 51. This prevents the inner periphery of the protective plate 52 from overlapping with the central portion 51a of the diaphragm 51, suppressing changes in the deformation characteristics of the diaphragm 51 in response to pressure differential. The protective plate 52 is configured to contact the surface (one side surface) of the outer periphery 51b of the diaphragm 51 on the side of the first outlet 14. Furthermore, in this embodiment, the protective plate 52 is made of the same material as the diaphragm 51 and has the same thickness as the diaphragm 51. The material of the diaphragm 51 can be a synthetic resin that can be used in refrigerants, such as HFC134a or HFO1234yf. The thickness of the diaphragm 51 is only required to be within a range that does not impair the deformation characteristics of the diaphragm 51. The protective plate 52 can also be configured to contact the surface of the outer periphery 51b of the diaphragm 51 on the side of the pressure differential valve chamber 13. In this embodiment, the inner diameter of the protective sheet 52 is slightly smaller than the outer diameter of the central portion 51a of the diaphragm 51, but the inner diameter of the protective sheet 52 can also be the same as the outer diameter of the central portion 51a. Furthermore, even when the inner diameter of the protective sheet 52 is set to be larger than the outer diameter of the central portion 51a, it still has the effect of suppressing damage to the diaphragm 51 caused by foreign objects.

[0043] The sealing member 53 is made of a synthetic resin such as polytetrafluoroethylene (PTFE). The sealing member 53 has an annular plate shape with the same outer diameter as the diaphragm 51. The sealing member 53 is configured to contact the side of the differential pressure valve chamber 13 in the outer periphery 51b of the diaphragm 51 (the other side).

[0044] The retaining component 54 is generally annular in shape. The retaining component 54 integrally comprises a cylindrical portion 54a and a flange portion 54b. The flange portion 54b is continuously disposed at one end (the right end in each figure) of the cylindrical portion 54a. The flange portion 54b has an annular plane 54c that contacts the protective sheet 52. The annular plane 54c and the cylindrical inner circumferential surface 54d of the cylindrical portion 54a are smoothly connected by a curved connecting surface 54e. The diameter of the inner circumferential surface 54d is larger than the inner diameter of the protective sheet 52.

[0045] A protective plate 52, the outer periphery 51b of the diaphragm 51, and a sealing member 53 are disposed between the retaining member 54 and the retaining surface 10b within the valve body 10. The gap between the protective plate 52 and the connecting surface 54e of the retaining member 54 gradually narrows as it moves radially outward.

[0046] Differential pressure valve frame 55 has one end ( Figure 1The left end of the differential pressure valve frame 55 is blocked. A flow hole 55a is formed at one end of the differential pressure valve frame 55. The inner space of the differential pressure valve frame 55 is connected to the first outlet 14 through the flow hole 55a. The other end of the differential pressure valve frame 55 is fitted into the cylindrical portion 54a of the retaining member 54. The other end of the differential pressure valve frame 55 is fixed to the valve body 10 by a threaded structure. The retaining member 54 is fixed relative to the valve body 10 by the differential pressure valve frame 55. The differential pressure valve frame 55 pushes the retaining member 54 toward the retaining surface 10b of the valve body 10. As a result, the protective plate 52, the outer periphery 51b of the diaphragm 51, and the sealing member 53 are held between the retaining member 54 and the retaining surface 10b of the valve body in an overlapping state.

[0047] The differential pressure valve core 56 has a generally circular plate shape. The differential pressure valve core 56 is configured in the differential pressure valve chamber 13 to slide in the left-right direction. On one end face of the differential pressure valve core 56 ( Figure 1 A circular gasket 56a is installed on the right end face of the diaphragm 51. The differential pressure valve core 56 is installed in the central portion 51a of the diaphragm 51. Specifically, the differential pressure valve core 56 and the stop 57 are engaged with each other, and the central portion 51a is held between the differential pressure valve core 56 and the stop 57. The stop 57 is disposed inside the differential pressure valve frame 55. When the differential pressure valve core 56 reaches the maximum opening position, the stop 57 abuts against the stop surface 55b of the differential pressure valve frame 55, thereby restricting the movement of the differential pressure valve core 56 in the opening direction. A closing valve spring 58 is disposed between the stop 57 and the differential pressure valve frame 55. The closing valve spring 58 is a compression helical spring and pushes the differential pressure valve core 56 to the right (closing direction) via the stop 57.

[0048] Next, an example of the operation of solenoid valve 1 will be described.

[0049] exist Figure 1 The image shows solenoid valve 1 in a state where no energizer is supplied to solenoid coil 34. Figure 1 In this process, the pilot valve core 36 (specifically, gasket 36a) leaves the pilot valve seat 45, opening the pilot valve seat 45. Simultaneously, the main valve core 40 (specifically, gasket 43a) leaves the main valve seat 17, opening the main valve seat 17. At this time, the refrigerant flowing into the main valve chamber 12 from the inlet 11 flows through the main valve seat 17 and the main valve port 16 to the first outlet 14, and then flows through the branch passage 18 to the differential pressure valve chamber 13. Therefore, the pressure difference between the differential pressure valve chamber 13 and the first outlet 14 becomes relatively small, such as... Figure 2 , Figure 3 As shown, the central portion 51a of the diaphragm 51 is a frustoconical shape protruding towards the differential pressure valve chamber 13. This causes the differential pressure valve core 56 (specifically, the gasket 56a) to contact the differential pressure valve seat 20, thus closing the differential pressure valve seat 20. When the differential pressure valve seat 20 is closed, the refrigerant in the differential pressure valve chamber 13 remains in the differential pressure valve chamber 13 and does not flow to the second outlet 15.

[0050] Then, when the solenoid coil 34 is energized, the plunger 33 is pulled towards the suction member 31, and the pilot valve core 36 moves downward. The pilot valve core 36 then contacts the pilot valve seat 45 and pushes the main valve core 40 downward, causing the main valve core 40 to contact the main valve seat 17. Thus, the pilot valve core 36 closes the pilot valve seat 45, the main valve core 40 closes the main valve seat 17, and the flow of refrigerant from the main valve chamber 12 to the first outlet 14 is cut off.

[0051] After the main valve core 40 closes the main valve seat 17, a short while later, the pressure at the first outlet 14 decreases relative to the pressure in the differential pressure chamber 13. Therefore, the pressure difference between the differential pressure chamber 13 and the first outlet 14 becomes relatively large. Figure 4 , Figure 5 As shown, the central portion 51a of the diaphragm 51 is deformed to protrude toward the first outlet 14. As a result, the differential pressure valve core 56 moves away from the differential pressure valve seat 20, opening the differential pressure valve seat 20. When the differential pressure valve seat 20 is open, the refrigerant in the differential pressure valve chamber 13 flows to the second outlet 15 via the differential pressure valve seat 20 and the differential pressure valve port 19.

[0052] Due to the deformation of the diaphragm 51, the gap between the protective sheet 52 and the connecting surface 54e of the retaining member 54 becomes smaller. As a result, foreign objects that enter this gap may sometimes become trapped between the protective sheet 52 and the retaining member 54. However, the protective sheet 52 is arranged to overlap with the outer periphery 51b of the diaphragm 51, preventing foreign objects from directly contacting the diaphragm 51.

[0053] Then, when the solenoid coil 34 is de-energized again, the plunger 33 is pushed upward by the valve-opening spring 38, the pilot valve core 36 leaves the pilot valve seat 45, and the pilot valve seat 45 opens. The refrigerant in the pilot valve chamber 37 flows to the first outlet 14 via the pilot valve seat 45 and the pilot valve port 44, and the force generated by the refrigerant pressing the main valve core 40 against the main valve seat 17 weakens. The main valve core 40 is pushed upward by the valve-opening spring 39, the main valve core 40 leaves the main valve seat 17, and the main valve seat 17 opens. Thus, the refrigerant in the main valve chamber 12 flows to the first outlet 14 via the main valve seat 17 and the main valve port 16. Therefore, the pressure difference between the differential pressure chamber 13 and the first outlet 14 becomes smaller, such as... Figure 2 , Figure 3 As shown, the central portion 51a of the diaphragm 51 returns to its original frustum-shaped form, protruding towards the differential pressure valve chamber 13. Consequently, the differential pressure valve core 56 contacts the differential pressure valve seat 20, thus closing the differential pressure valve seat 20.

[0054] As described above, the solenoid valve 1 has a valve body 10, which includes: an inlet 11; a main valve chamber 12 connected to the inlet 11; a first outlet 14 connected to the main valve chamber 12 via a main valve seat 17; a differential pressure valve chamber 13 connected to the main valve chamber 12 via a branch passage 18; and a second outlet 15 connected to the differential pressure valve chamber 13 via a differential pressure valve seat 20. The solenoid valve 1 also includes: a main valve core 40 disposed in the main valve chamber 12 for opening and closing the main valve seat 17; a diaphragm 51 made of synthetic resin configured to divide the differential pressure valve chamber 13 from the first outlet 14; an annular retaining member 54 fixed relative to the valve body 10; and a differential pressure valve core 56 disposed in the differential pressure valve chamber 13 and moved by the diaphragm 51. The solenoid valve 1 has a ring-shaped protective plate 52 made of synthetic resin, which is configured to contact the surface of the first outlet 14 side (i.e., the retaining member 54 side) in the outer periphery 51b of the diaphragm 51. The outer periphery 51b of the diaphragm 51 and the protective plate 52 are held between the retaining surface 10b of the valve body and the retaining member 54.

[0055] In this way, when the diaphragm 51 deforms, the foreign object is trapped between the retaining member 54 and the protective plate 52, preventing the foreign object from directly contacting the diaphragm 51. Therefore, damage to the diaphragm 51 can be suppressed in the solenoid valve 1.

[0056] Furthermore, when there is no pressure difference between the differential pressure valve chamber 13 and the first outlet 14, the central portion 51a of the diaphragm 51 is truncated cone-shaped. Moreover, the differential pressure valve core 56 is mounted on the central portion 51a of the diaphragm 51. This increases the amount of movement of the differential pressure valve core 56.

[0057] Furthermore, the retaining member 54 has: an annular plane 54c that contacts the protective sheet 52; a cylindrical inner circumferential surface 54d; and a curved connecting surface 54e that smoothly connects the annular plane 54c and the inner circumferential surface 54d. Moreover, the inner diameter of the protective sheet 52 is smaller than the diameter of the inner circumferential surface 54d of the retaining member 54. In this way, the protective sheet 52 is configured to be integrally opposite the connecting surface 54e, which more reliably prevents foreign objects from being trapped between the diaphragm 51 and the connecting surface 54e, and further suppresses damage to the diaphragm 51.

[0058] Furthermore, the solenoid valve 1 has an annular sealing member 53, which is configured to overlap with the surface of the differential pressure valve chamber 13 side (i.e., the valve body 10 side) in the outer periphery 51b of the diaphragm 51. The sealing member 53, the outer periphery 51b of the diaphragm 51, and the protective plate 52 are held between the retaining surface 10b of the valve body and the retaining member 54. In this way, the diaphragm 51 and the valve body 10 can be effectively sealed, and the differential pressure valve chamber 13 and the first flow outlet 14 can be effectively sealed to each other.

[0059] Furthermore, the solenoid valve 1 in this embodiment is a composite valve having a solenoid valve section 30 and a differential pressure valve section 50, but the present invention can also be applied to a single differential pressure valve.

[0060] The embodiments of the present invention have been described above, but the present invention is not limited to these examples. Those skilled in the art can appropriately add or delete constituent elements, make design changes, or appropriately combine features of the embodiments described above, as long as such additions or deletions do not violate the spirit of the present invention, and these modifications are included within the scope of the present invention.

[0061] Explanation of symbols

[0062] 1…Solenoid valve with differential pressure valve, 10…Valve body, 10a…Left side face, 10b…Retaining face, 11…Inlet, 12…Main valve chamber, 13…Differential pressure valve chamber, 14…First outlet, 15…Second outlet, 16…Main valve port, 17…Main valve seat, 18…Branch passage, 19…Differential pressure valve port, 20…Differential pressure valve seat, 30…Solenoid valve section, 31…Suction element, 31a…Large diameter cylindrical section, 31b…Small diameter cylindrical section, 32…Housing, 33…Plunger, 34…Solenoid coil, 35…Valve shaft, 35a…Fluid passage, 36…Pilot valve core, 36a…Gasket, 37…Pilot valve chamber, 38, 39…Opening valve Spring, 40…Main valve core, 41…Body, 42…Upper flange, 42a…Equalizing passage, 43…Lower flange, 43a…Gasket, 44…Pilot valve port, 45…Pilot valve seat, 50…Differential pressure valve section, 51…Diaphragm, 51a…Central section, 51b…Outer periphery, 52…Protective plate, 53…Sealing component, 54…Retaining component, 54a…Cylindrical section, 54b…Flange, 54c…Annular plane, 54d…Inner circumferential surface, 54e…Connecting surface, 55…Differential pressure valve frame, 55a…Flow hole, 55b…Stop surface, 56…Differential pressure valve core, 56a…Gasket, 57…Stop, 58…Closing spring.

Claims

1. A pressure differential valve having: a valve body having a valve chamber and a back pressure chamber; a diaphragm made of synthetic resin configured to divide the valve chamber and the back pressure chamber; a retaining member of a circular ring shape fixed with respect to the valve body; and a valve element configured in the valve chamber, which moves through the diaphragm, characterized in that: a central portion of the diaphragm is a circular truncated cone shape projecting toward the valve chamber side in a state where there is no pressure differential between the valve chamber and the back pressure chamber, the valve element is attached to the central portion of the diaphragm, the pressure differential valve has a sealing member of a circular ring shape configured to contact a surface of the valve chamber side of an outer peripheral portion of the diaphragm, and a protective sheet of a circular ring shape made of synthetic resin configured to contact a surface of the back pressure chamber side of the outer peripheral portion of the diaphragm, and the sealing member, the outer peripheral portion of the diaphragm, and the protective sheet are retained between the valve body and the retaining member.

2. The pressure differential valve according to claim 1, characterized in that: the sealing member is made of polytetrafluoroethylene.

3. The pressure differential valve according to claim 1, characterized in that: an inner diameter of the protective sheet is smaller than an outer diameter of the central portion of the diaphragm.

4. The pressure differential valve according to any one of claims 1 to 3, characterized in that: the retaining member has a circular ring plane contacting the protective sheet, a cylindrical inner peripheral surface, and a connecting surface of a curved surface shape smoothly connecting the circular ring plane and the inner peripheral surface, and an inner diameter of the protective sheet is smaller than a diameter of the inner peripheral surface of the retaining member.

5. A valve device having: a valve body having a flow inlet, a main valve chamber connected to the flow inlet, a first flow outlet connected to the main valve chamber via a main valve seat, a pressure differential valve chamber connected to the main valve chamber via a branch passage, and a second flow outlet connected to the pressure differential valve chamber via a pressure differential valve seat; a main valve element configured in the main valve chamber, which opens and closes the main valve seat; a diaphragm made of synthetic resin configured to divide the pressure differential valve chamber and the first flow outlet as a back pressure chamber; a retaining member of a circular ring shape fixed with respect to the valve body; and a pressure differential valve element configured in the pressure differential valve chamber, which moves through the diaphragm, characterized in that: there is a sealing member of a circular ring shape configured to contact a surface of the pressure differential valve chamber side of an outer peripheral portion of the diaphragm, and a protective sheet of a circular ring shape made of synthetic resin configured to contact a surface of the first flow outlet side of the outer peripheral portion of the diaphragm, a central portion of the diaphragm is a circular truncated cone shape projecting toward the pressure differential valve chamber side in a state where there is no pressure differential between the pressure differential valve chamber and the first flow outlet, the pressure differential valve element is attached to the central portion of the diaphragm, and the sealing member, the outer peripheral portion of the diaphragm, and the protective sheet are retained between the valve body and the retaining member. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Images