JP4464259B2 - Pressure reducing valve - Google Patents

Description

  The present invention relates to a pressure reducing valve provided, for example, in a fluid pressure device.

  FIG. 8 is a cross-sectional view schematically showing the pressure reducing valve 1 of the prior art in a simplified manner. The pressure reducing valve 1 has a housing 2, a piston 3 and a spring member 4. A piston 3 is provided in the housing 2 so as to be displaceable in the axial direction. In the housing 2, the piston 3 is formed long in the axial direction, and is held at two positions, one end in the axial direction and an intermediate portion. The spring member 4 applies a spring force toward the piston 3 in one axial direction. In the housing 2, a primary port 5 and a secondary port 6 are formed, and a protruding piece 7 is formed so as to be surrounded by the primary port 5. An orifice 9 for depressurization is formed by the protruding piece 7 and the seat portion 8 of the piston 3 facing the protruding piece 7. The interior of the housing 2 is partitioned by the orifice 9 into a primary pressure chamber 10 connected to the primary port 5 and a secondary pressure chamber 11 connected to the secondary port 6. The pressure reducing valve 1 reduces the pressure of the primary pressure p 1 supplied to the primary port 5 to the secondary pressure p 2 by passing through the orifice 9 and discharges the fluid from the secondary port 6.

JP 2003-150249 A (page 7, FIG. 4)

  The conventional pressure reducing valve has the following problems (1) and (2) because the long piston 3 is held at two positions, one end in the axial direction and the middle.

  (1) When the coaxiality of the holding parts 12 and 13 holding the one end part and the intermediate part of the piston 3 in the axial direction is low, nonuniform contact surface pressure acts on the piston 3 in the circumferential direction. 3 is held in a single-contacted state in the housing 2. As a result, an undesired frictional force acts on the piston 3 and hysteresis is generated in the decompression characteristic. When the frictional force acting on the piston is further increased, the hysteresis of the pressure reducing characteristic is increased, and it becomes difficult to control the pressure reducing valve.

  (2) In order to improve this, it is necessary to increase the coaxiality of the holding portions 12 and 13. In order to increase the coaxiality of the holding portions 12 and 13, the required processing accuracy of the housing 2 must be increased, that is, the coaxiality tolerance needs to be reduced. As a result, the manufacturing cost for processing the housing 2 increases, and mass production of the pressure reducing valve 1 becomes difficult.

  An object of the present invention is to provide a pressure reducing valve that facilitates control of the pressure reducing valve and can reduce the manufacturing cost.

The present invention is a housing in which a primary port and a secondary port are formed, and a guide bush is formed at one end of the housing in the axial direction, and the guide bush is fitted into the other end in the axial direction. A housing having
A pressure-reducing piston held in a housing by a guide part so as to be displaceable , receiving a primary pressure at one end thereof, adjusting the opening degree of the primary port by the displacement, and a primary pressure chamber and a secondary port connected to the primary port a pressure reducing piston off specification within the housing to a secondary pressure chamber communicating with,
A drive piston which is displaceably held by a guide bush in the housing, in direct contact to the other end portion opposite to displace in conjunction with vacuum pistons and the end portion for receiving a primary pressure reduced pressure piston and Bei obtain drive piston of the secondary pressure receiving surface for receiving the secondary pressure from the fluid in the secondary pressure chamber,
Spring means for applying a spring force against the secondary pressure to at least one of the decompression piston and the drive piston ;
A first rod that is inserted into the pressure reducing piston so as to be displaceable and forms a back pressure chamber that is held at the primary pressure between the pressure reducing piston and the pressure reducing piston;
A pressure reducing valve comprising: a second rod held by a housing, the second rod supporting the first rod and applying a pressing force against the primary pressure applied to the first rod. is there.

According to the present invention, the fluid flowing from the primary port flows into the secondary pressure chamber through the primary pressure chamber. The drive piston is subjected to a secondary pressure from the fluid entering the secondary pressure chamber to the secondary pressure receiving surface. When the secondary pressure is greater than the spring force provided by the spring means, the drive piston is displaced in the housing. The decompression piston receives a primary pressure at one end thereof, and is displaced in conjunction with the displacement of the drive piston that directly contacts the other end opposite to the one end, thereby adjusting the opening of the primary port. By adjusting the opening degree of the primary port, the flow rate of the fluid flowing from the primary pressure chamber into the secondary pressure chamber is adjusted, and the secondary pressure of the fluid discharged from the secondary port is reduced. In this way, the drive piston including the secondary pressure receiving surface that receives the secondary pressure and the pressure-reducing piston that adjusts the opening degree of the primary port are formed separately.

The first rod forms a back pressure chamber which is held in the primary pressure between a pressure reduction piston. The pressure reducing piston is given a primary pressure by the fluid in the back pressure chamber against a primary pressure received from the fluid in the primary pressure chamber. The second rod, the pressing force against the primary pressure applied to the first rod provided to the first rod, for supporting the first rod. As a result, a back pressure chamber maintained at the primary pressure can be formed, and the first rod inserted into the decompression piston and the second rod provided in the housing are formed separately.

In the present invention, the second rod is characterized in that a support surface for supporting the first rod is formed in a partial spherical shape.

According to the present invention, the support surface for supporting the first rod of the second rod is formed in a partial spherical shape. Even if this the second rod supporting the first rod in a state that is tilted with respect to the first rod, without the support surfaces to uneven contact with respect to the first rod, supporting the first rod To do.

According to the present invention, setting the decompression piston are in direct contact with the vacuum piston is displaced in conjunction with displacement of the drive piston only, with these driving piston and the pressure reducing piston, by adjusting the opening of the primary port, the primary pressure By adjusting the flow rate of the fluid flowing from the chamber into the secondary pressure chamber, the secondary pressure of the fluid discharged from the secondary port can be reduced. Thus, since a drive piston and a pressure reduction piston are formed separately, the following effects are produced. Since it is not always necessary to form the drive piston and the decompression piston on the same axis, the coaxiality tolerance between the drive piston and the decompression piston can be allowed to be larger than that of the prior art. Therefore, the processing accuracy required for the housing holding the drive piston and the decompression piston can be relaxed to be lower than that of the prior art, and the housing can be processed easily. Thereby, the manufacturing cost of the pressure reducing valve can be reduced. By making the housing easy to process, mass production of the pressure reducing valve can be facilitated.

  Further, since the drive piston and the decompression piston are formed separately, the drive piston and the decompression piston can be formed shorter than the conventional piston. Further, the contact of the drive piston and the decompression piston with respect to the housing can be suppressed. In other words, the non-uniform frictional force acting on the drive piston and the decompression piston can be reduced compared to the piston according to the prior art. By reducing the non-uniform frictional force in the circumferential direction, the hysteresis of the pressure reducing characteristic of the pressure reducing valve can be made smaller than before.

  Therefore, it is possible to realize a pressure reducing valve that facilitates control of the pressure reducing valve and can reduce the manufacturing cost.

Further , since the first rod and the second rod are formed separately, it is not necessary to form them on the same axis, and the coaxiality tolerance between the first rod and the second rod is larger than that of the prior art. Can be tolerated. Therefore, the processing accuracy required for the decompression piston holding the first rod can be relaxed to be lower than that of the prior art, and the processing of the decompression piston is facilitated. Accordingly, even when a back pressure chamber is formed between the pressure reducing piston and the first rod, the manufacturing cost of the pressure reducing valve can be reduced. Since the processing of the pressure reducing piston becomes easy, mass production of pressure reducing valves becomes possible.

Further, since the first rod and the second rod are formed separately, the first rod and the second rod are formed shorter than when the first rod and the second rod are integrally formed. Thereby, the contact surface pressure of the first rod with respect to the decompression piston becomes uniform over the entire circumference in the circumferential direction as compared with the case where the first rod is integrally formed. Therefore, the contact of the first rod with the decompression piston can be suppressed. As a result, it is possible to reduce the non-uniform frictional force acting on the first rod in the circumferential direction as compared with the case where the first rod hits one side. As a result, the hysteresis of the pressure reducing characteristic of the pressure reducing valve can be reduced.

According to the present invention, even if the second rod supporting the first rod in a state that is tilted with respect to the first rod, without the support surfaces to uneven contact with respect to the first rod, the second 1 rod is supported. Therefore, the contact surface pressure of the first rod with respect to the decompression piston becomes uniform over the entire circumference. As a result, a non-uniform frictional force acting on the first rod in the circumferential direction can be reduced, and the hysteresis of the pressure reducing characteristic of the pressure reducing valve based on this frictional force can be reduced.

  Hereinafter, a plurality of embodiments for carrying out the present invention will be described with reference to the drawings. Portions corresponding to the matters described in the preceding forms in each embodiment are denoted by the same reference numerals, and overlapping description may be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in the preceding section. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination is not particularly troublesome.

FIG. 1 is a sectional view showing a pressure reducing valve 20 according to a first embodiment of the present invention. FIG. 2 is an enlarged view showing the rod 24 and the base rod 25. The pressure reducing valve 20 is a valve that is interposed in a flow path where the fluid flows down from the primary side to the secondary side, and discharges the supplied primary pressure p1 by reducing the pressure to a secondary pressure p2 lower than the primary pressure. The pressure reducing valve 20 includes a housing 21, a pressure reducing piston 22, a drive piston 23, a rod 24 as a first rod, a base rod 25 as a second rod, a first spring member 26, a second spring member 27, and a third spring member. 19 is comprised. The housing 21, the decompression piston 22, the drive piston 23, the rod 24, the base rod 25, the first spring member 26, the second spring member 27, and the third spring member 19 have different axes depending on design and processing errors. It is formed on the line. For example, due to an error caused by forming within a predetermined range of coaxiality tolerance, these axes are shifted from each other, formed on different axes, and provided on an axis different from the axis L1 of the pressure reducing valve 20. Yes. Below, for convenience of explanation, these are provided coaxially with each other, and the axes of these axes are described as being provided coaxially with the axis L1 of the pressure reducing valve 20. The same applies to other embodiments.

The housing 21 includes a first housing 28 that holds the decompression piston 22, the drive piston 23, the rod 24, and the base rod 25, and a second housing 31 in which a primary port 29 and a secondary port 30 are formed. The first housing 28 is generally cylindrical with a bottom, and includes a bottomed cylindrical main body 32, a substantially cylindrical base 33, and a cylindrical guide bush 34. The main body 32, the base 33, and the guide bush 34 are provided coaxially with each other, and the axes of these axes are provided coaxially with the axis L1 of the pressure reducing valve. The base portion 33 is formed with a flange-like outward convex portion 35 protruding outward in the radial direction at the intermediate portion in the axial direction and extending in the entire circumferential direction. The outer peripheral edge portion of the outward convex portion 35 is the main body portion 32. To the open end of In the first housing 28 formed in this way, one end 36 in the axial direction of the base 33 opens toward the outside of the first housing 28, and the other end 37 in the axial direction of the base 33 is formed in the first housing 28. Open inward. In the following, one axial direction X1 is defined as a direction from the opening end 38 that is one axial end of the first housing 28 toward the bottom 39 that is the other axial end of the first housing 28, and the other axial X2 is the first. The direction is from the open end 38 of the housing 28 toward the bottom 39.

  The decompression piston 22 is formed in a bottomed cylindrical shape, and a portion on the axial end portion 40 side that is a bottom portion of the decompression piston 22 protrudes from the axial end portion 36 of the base portion 33 to the other axial direction X2, and the remaining portion is inserted into the base portion 33. Is done. The decompression piston 22 has a flange-like decompression piston convex portion 42 that protrudes outward in the radial direction and extends in the entire circumferential direction at the other end portion 41 in the axial direction that is an opening end portion thereof. The decompression piston 22 is held in the first housing 28 so as to be displaceable in the axial direction X in a state where a part of the decompression piston 22 is inserted into the base portion 33.

  The base portion 33 of the first housing is formed with a flange-shaped guide portion 43 that protrudes inward in the radial direction and extends in the entire circumferential direction at one axial end portion 36 thereof. A flange-like base inward protruding portion 44 that protrudes inward in the radial direction and extends over the entire circumference in the axial direction intermediate portion of the axial direction is formed in the axial direction X with respect to the guide portion 43. Formed at intervals. The decompression piston 22 is held by an inner peripheral portion of the guide portion 43 so that the outer peripheral portion near the axial one end portion 40 of the intermediate portion in the axial direction can be displaced in the axial direction X. The decompression piston convex portion 42 has an outer peripheral portion having a smaller diameter than an inner peripheral portion of a portion between the base guide portion 43 and the base inward convex portion 44. In the decompression piston 22, the decompression piston convex portion 42 is disposed between the guide portion and the base inward convex portion 44.

  Between the decompression piston convex part 42 and the guide part 43, the decompression piston 22 and the base part 33 are formed at an interval in the radial direction. Thus, an annular first spring accommodating space 45 is formed between the decompression piston convex portion 42 and the guide portion 43. A first spring member 26 that is a compression coil spring is disposed in the first spring accommodating space 45. The first spring member 26 is externally fitted to a part of the decompression piston 22, one end in the axial direction is supported by the guide portion 43, and the other end in the axial direction is supported by the decompression piston convex portion 42.

  The drive piston 23 has a substantially cylindrical shape, a portion on the axial direction one end portion 46 side is inserted into the base portion 33, and a portion on the axial direction other end portion 47 side is the other end portion 37 in the axial direction of the base portion 33. Projecting in the axial direction X1. The drive piston 23 is inserted into the base 33 and its one axial end 46 abuts on the other axial end 41 of the decompression piston 22. The decompression piston 22 is given a spring force toward the one axial direction X <b> 1 by the first spring member 26, and its other axial end 41 is in contact with one axial end 46 of the drive piston 23. In this state, the drive piston 23 is held in the first housing 28 so as to be displaceable in the axial direction X.

  The drive piston 23 is formed in a stepped shape in which the outer peripheral portion of the axial one end 46 is recessed radially inward over the entire circumferential direction. By forming in this way, the axial direction one end part 46 and the base part 33 of the drive piston 23 are arranged at intervals. As a result, an annular base inner space 48 is formed between the axial end portion 46 of the drive piston 23 and the base portion 33. A first seal recess 50 that is recessed inward in the radial direction is formed on the outer peripheral portion of the drive piston 23 near the axial direction one end 46 of the intermediate portion in the axial direction so as to fit the annular seal member 49. An annular seal member 49 is fitted into the first seal recess 50. The drive piston 23 is inserted into the base 33 in a state where the outer peripheral portion of the axially intermediate portion near the axial one end 46 and the inner peripheral portion of the base inward convex portion 43 achieve a seal.

  The base 33 is fitted with a cylindrical guide bush 34 on the inner periphery of the other axial end 37. One end of the guide bush 34 in the axial direction is supported by the base inward convex portion 44 and held by the base 33. The drive piston 23 is held such that the outer peripheral portion of the intermediate portion in the axial direction is displaceable in the axial direction X on the inner peripheral portion of the guide bush 34.

  The other end 47 in the axial direction of the drive piston 23 is formed with a flange-like drive piston convex portion 51 protruding outward in the radial direction and extending in the entire circumferential direction. In order to fit the annular seal member 52, the drive piston convex portion 51 is formed with a second seal concave portion 53 that is recessed radially inward in the outer peripheral portion. An annular seal member 52 is fitted in the second seal recess 53. The drive piston convex portion 51 is inserted into the outer peripheral portion of the outer peripheral portion of the main body portion 32 near the bottom portion 39 in the axial direction intermediate portion. The drive piston convex portion 52 and the outer peripheral portion achieve a seal by the seal member 52 fitted into the second seal concave portion 53.

Between the drive piston convex part 51 and the outward convex part 35, the inner peripheral part of the main-body part 32 and the outer peripheral part of the base part 33 are formed at intervals in the radial direction. Thereby, an annular second spring accommodating space 54 is formed between the drive piston convex portion 51 and the outward convex portion 35. The second spring accommodating space 54 is opened to the atmosphere by an atmospheric opening hole 55 formed in the outer peripheral portion of the main body 32 and penetrating in the radial direction. A second spring member 27 that is a compression coil spring is disposed in the second spring accommodating space 54. The second spring member 27 is externally fitted to a part of the outer peripheral portion of the base portion 33 on the other end side in the axial direction 37, one end in the axial direction is supported by the outward projecting portion 35, and the other end in the axial direction is driven. Supported by the piston protrusion 51. The spring means 18 is formed by the second spring member 27 and the first spring member 26 .

  The decompression piston 22 is formed with a seal recess 57 that is recessed outward in the radial direction and extends in the entire circumference in order to fit the annular seal member 56 to the inner periphery of the intermediate portion in the axial direction. An annular seal member 56 is fitted in the seal recess 57. A portion of one end side 58 in the axial direction of the rod 24 formed in a substantially cylindrical shape is inserted into the decompression piston 22. The portion of the rod 24 on the other end 59 side in the axial direction protrudes from the other end 41 in the axial direction of the decompression piston 22 to one X1 in the axial direction. In this state, the rod 24 is inserted into the decompression piston 22 so as to be displaceable in the axial direction X. The rod 24 and the pressure-reducing piston 22 achieve a seal with a seal member 56. A back pressure chamber 61 is formed between one axial end 58 of the rod 24 and the bottom 60 of the decompression piston 22.

  The drive piston 23 is formed with an inward convex portion 62 that protrudes inward in the radial direction and extends in the entire circumferential direction at one axial end portion 46 thereof. The inner peripheral portion of the inward convex portion 62 is formed to have a larger diameter than the outer peripheral portion of the rod 24. The portion of the drive piston 23 on the other end 59 side in the axial direction of the rod 24 is inserted through the portion on the one end 46 side in the axial direction. In this way, the rod 24 is inserted into the drive piston 23 and the decompression piston 22, and the outer peripheral portion of the portion on the axial end portion 58 side is held displaceably on the inner peripheral portion of the decompression piston 22.

  The rod 24 is formed with a flange-like rod convex portion 63 whose other axial end portion 59 projects outward in the radial direction and extends all around the circumferential direction. The rod convex portion 63 is formed so that its outer peripheral portion can be inserted into the inner peripheral portion of the drive piston 23. Between the rod convex portion 63 and the inward convex portion 62, the rod 24 and the drive piston 23 are formed at a radial interval. Thereby, an annular third spring accommodating space 64 is formed between the rod convex portion 63 and the inward convex portion 62. A third spring member 19 that is a compression coil spring is disposed in the third housing space 64. The third spring member 19 is externally fitted to a part of the outer peripheral portion of the rod 24, one end in the axial direction is supported by the inward convex portion 62, and the other end in the axial direction is supported by the rod convex portion 59. The third spring member 19 applies a spring force directed to the rod 24 in the axial direction one X1.

  The base rod 25 is generally cylindrical and has a small diameter portion 65, a medium diameter portion 66, and a large diameter portion 67. The small-diameter portion 65 has a support surface 68 that is a surface of one end in the axial direction formed in a partial spherical shape, and one end in the axial direction of the medium-diameter portion 66 is connected to the other end in the axial direction. The middle diameter portion 66 is connected to the other end portion in the axial direction at one end portion in the axial direction of the large diameter portion 67. The small diameter portion 65 is formed to have a smaller diameter than the medium diameter portion 66, and the medium diameter portion 66 is formed to have a smaller diameter than the large diameter portion 67. The small-diameter portion 65, the medium-diameter portion 66, and the large-diameter portion 67 are integrally formed, and each axis is formed coaxially.

  The medium diameter portion 66 is formed with a first through hole 69 penetrating in the radial direction at a portion on one end side in the axial direction. The large-diameter portion 67 is formed with a second through hole 70 penetrating in the radial direction at a portion on the one end side in the axial direction. Further, a third through hole 71 extending in the axial direction is formed in the medium diameter portion 66 and the large diameter portion 67 along the axis L1. The third through hole 71 communicates the first through hole and the second through hole. A through hole 72 is formed by the first to third through holes 69, 70 and 71.

  The main body 32 is formed with a fitting recess 73 that is recessed in one axial direction X1 at the bottom 39 thereof. The fitting recess 73 is formed so that the other end 74 in the axial direction of the large diameter portion 67 can be fitted. The base rod 25 is held with the other axial end portion 74 of the large-diameter portion 67 fitted into the fitting recess 73 and the remaining portion protruding from the fitting recess 73 to the other axial direction X2. The base rod 25 is formed so that the medium diameter portion 66 can be inserted into the drive piston 23, and the small diameter portion 65 and the medium diameter portion 66 are inserted into the drive piston 23. The base rod 25 has a large-diameter portion 67 having a larger diameter than the inner peripheral portion of the drive piston 23, and protrudes from the other axial end portion 47 of the drive piston 23 in one axial direction X <b> 1.

  The small-diameter portion 65 is formed in a partial spherical shape with the support surface 68 curved convexly toward the other axial direction X1. In the small diameter portion 65, the support surface 68 comes into contact with the other axial end portion 59 of the rod 24. In order to bring the rod 24 into contact with the support surface 68, a spring force is applied to the rod 24 toward the one axial direction X <b> 1 by the third spring member 19. The small diameter part 65 and the medium diameter part 66 and the drive piston 23 are formed at intervals in the radial direction. As a result, an annular drive piston inner space 75 is formed between the small diameter portion 65 and the medium diameter portion 66 and the drive piston 23. The drive piston inner space 75 continues to the second through hole 69.

  The large-diameter portion 67 has one end in the axial direction protruding from the fitting recess 73 to the other axial direction X2, and the outer peripheral edge of the one axial end is in contact with the inner peripheral edge of the other axial end 47 of the drive piston 25. It is possible to arrange. The drive piston 23 is given a spring force toward the one axial direction X1 by the second spring member 27. By the large diameter portion 67, the bottom 39 of the main body portion 32 and the outer peripheral edge portion of the other end portion 47 in the axial direction of the drive piston 23 are arranged with a gap in the axial direction. As a result, an annular secondary space 76 is formed between the bottom 39 of the main body 32 and the outer peripheral edge of the other axial end 47 of the drive piston 23. The secondary space 76 continues to the third through hole 71. The secondary side space 76 and the drive piston inner space 75 are communicated with each other through a through hole 72.

  The second housing 31 is formed with a cylindrical recess 77 that is recessed in the other axial direction X2. The concave portion 78 forming the concave portion 77 is formed such that a portion on the axial direction one end portion 36 side of the base portion 33 is inserted and this portion can be screwed. A portion of the base 33 on the one end 40 in the axial direction is screwed into the recess 78 in a state where a seal is achieved over the entire circumference. In a state where the first housing 28 is screwed, the bottom 79 of the recess 78 and the open end 38 of the first housing 28 face each other and are spaced apart in the axial direction X. As a result, a space 80 is formed between the bottom 79 of the recess 78 and the axial one end 40 of the first housing 28.

  The second housing 31 is inserted through the bottom 79 of the recess 78 along the axis L 1, and the primary port 29 that is continuous with the space 80 is formed. The secondary housing 31 is inserted in the inner peripheral portion of the recess 78 in the radial direction and is continuous with the space 80. A port 30 is formed. The bottom 79 is formed with an annular projecting piece 81 that projects in a tapered shape in one axial direction X1. The protruding piece 81 is formed to extend all around the circumferential direction so as to surround the primary port 29. The decompression piston 22 is formed with an annular seat portion 82 made of a special resin extending in the circumferential direction at one end portion 40 in the axial direction. The sheet portion 82 is formed to face the protruding piece 81 in the axial direction X. The sheet portion 82 and the projecting piece 81 form an annular orifice 83 that extends all around the circumferential direction. The space 80 has two regions connected through the orifice 83. Specifically, the space 80 includes a primary pressure chamber 84 that is a region formed radially inward from the orifice, and a secondary region 85 that is a region radially outward from the orifice 83. The primary port 29 is connected to the primary pressure chamber 84, and the secondary port 30 is connected to the secondary side region 85.

The decompression piston 22 is formed with a through-hole 86 that is inserted along the axis L1 at one end 40 in the axial direction thereof. The through hole 86 communicates the primary pressure chamber 84 and the back pressure chamber 61 . In the first housing 28, a communication hole 87 that communicates the secondary region 85 and the first spring accommodating space 45 is formed in a portion of the base portion 33 on the one end portion 36 side in the axial direction.

  The decompression piston 22 is disposed in the base portion 33 with the outer peripheral portion of the decompression piston convex portion 42 spaced radially from the inner peripheral portion of the base portion 33. Thus, an annular first gap 88 is formed between the outer peripheral portion of the decompression piston convex portion 42 and the inner peripheral portion of the base portion 33. The first gap 88 communicates the first spring accommodating space 45 and the base inner space 48. An insertion hole 89 is formed at one end 46 in the axial direction of the drive piston so as to be inserted inward and outward in the radial direction.

  The rod 24 is disposed in the drive piston 23 with an outer peripheral portion spaced radially from the inner peripheral portion of the inwardly convex portion 62 of the drive piston. As a result, an annular second gap 90 is formed between the outer peripheral portion of the rod 24 and the inner peripheral portion of the inwardly convex portion 62, extending in the entire circumferential direction. The insertion hole 89 communicates the second gap 90 and the base inner space 48, and the second gap 90 communicates with the third spring accommodating space 64. Therefore, the base inner space 48 is communicated with the third spring accommodating space 64 by the insertion hole 89 and the second flow path 90. Further, the rod 24 is arranged such that the outer peripheral portion of the rod convex portion 63 is spaced from the inner peripheral portion of the drive piston 23 in the radial direction. As a result, an annular third gap 91 is formed between the outer peripheral portion of the rod convex portion 63 and the inner peripheral portion of the drive piston 23. The third gap 91 communicates the third spring accommodating space 64 and the drive piston inner space 75.

  A primary pressure chamber 84 connected to the primary port 29 is configured by a region formed radially inward from the orifice 83. Secondary region 85 of space 80, communication hole 87, first spring accommodating space 45, first gap 88, base inner space 48, insertion hole 89, second gap 90, third spring accommodating space 64, third gap 91 A secondary pressure chamber 92 connected to the secondary port 30 is configured including the decompression piston inner space 75, the through hole 72, and the secondary side space 76. Further, the primary pressure chamber 84 and the back pressure chamber 61 are connected by the through hole 86.

  In such a pressure reducing valve 20, the pressure reducing piston 22 partitions the inside of the first housing 21 into a primary pressure chamber 84 and a secondary pressure chamber 92 that are connected by an orifice 83. The fluid supplied to the primary port 29 flows from the primary pressure chamber 84 through the orifice 83 to the secondary pressure chamber 92, specifically to the secondary side region 85. A part of the fluid flowing down to the secondary region 85 flows down to the secondary port 30 and is discharged from the secondary port 30. The remaining portions are the communication hole 87, the first spring accommodating space 45, the first gap 88, the base inner space 48, the insertion hole 89, the second gap 90, the third spring accommodating space 64, the third gap 91, and the pressure reducing piston. It flows down to the secondary space 76 through the space 75 and the through hole 72.

  As the fluid passes through the orifice 83, the pressure of the fluid decreases. In other words, the fluid is depressurized by flowing from the primary pressure chamber 84 through the orifice 83 to the secondary pressure chamber 92. Therefore, the fluid in the primary pressure chamber 84 and the back pressure chamber 61 connected to the primary pressure chamber 84 has a primary pressure p1, and the fluid in the secondary pressure chamber 92 has a secondary pressure p2 smaller than the primary pressure p1.

  The secondary pressure receiving surface 93, which is the surface of the other end 47 in the axial direction of the drive piston 23, receives thrust toward the other in the axial direction from the fluid of the secondary pressure p <b> 2 flowing down into the secondary side space 76. The secondary pressure receiving surface 93 corresponds to a secondary pressure receiving surface. When this thrust is larger than the spring force toward one axial direction X1 based on the second spring member 27 and the first spring member 26, the drive piston 23 presses the pressure-reducing piston 22 and moves the guide bush 34 to the other axial direction X2. Sliding displacement. The pressure-reducing piston 22 that is pressed slides and displaces the guide portion 43 in the other axial direction X2 in conjunction with the displacement of the drive piston 23. As a result, the interval in the axial direction X between the sheet portion 82 and the protruding piece 81 is reduced. Thus, the space | interval of the axial direction X between the sheet | seat part 82 and the protrusion piece 81 is narrowed, the flow volume of the fluid which passes the orifice 83 decreases, and the secondary pressure p2 is further reduced.

  When the thrust becomes smaller than the spring force directed to one axial direction X1 based on the second spring member 27 and the first spring member 26, the drive piston 23 is pushed up by the second spring member 27 to one axial direction X1, and the decompression piston 22 is The first spring member 26 is pushed up in one axial direction X1. As a result, the distance in the axial direction X between the sheet portion 82 and the protruding piece 81 is increased. Thus, the space | interval of the axial direction X between the sheet | seat part 82 and the protrusion piece 81 is widened, the flow volume of the fluid which passes the orifice 83 increases, and the secondary pressure p2 is increased.

  The rod 24 receives a primary pressure p1 from the fluid in the back pressure chamber 61 toward the axial direction one X1 at one axial end 58 thereof. The rod 24 is supported by the support surface 68 by applying a pressing force against the primary pressure p <b> 1 from the base rod 25. Therefore, the rod 24 is supported by the base rod 25, that is, the displacement of the rod 24 in one axial direction relative to the housing 21 is restricted. As a result, the back pressure chamber 61 can be held at the primary pressure p <b> 1 and the rod 24 can be prevented from being detached from the decompression piston 25.

  Below, the effect which the pressure-reduction valve 20 of the 1st embodiment shows is explained. According to the pressure reducing valve 20 of the present embodiment, the pressure reducing piston 22 that is displaced in conjunction with the displacement of the drive piston 23 is provided, and the opening degree of the primary port 29 is adjusted by the drive piston 23 and the pressure reducing piston 22. Thus, the flow rate of the fluid flowing into the secondary pressure chamber 92 from the primary pressure chamber 84 can be adjusted, and the secondary pressure of the fluid discharged from the secondary port 30 can be reduced. If the drive piston 23 and the pressure-reducing piston 22 are formed separately as described above, the drive piston 23 and the pressure-reduced piston 22 do not necessarily have to be formed coaxially. Tolerances can be tolerated more than in the prior art. Therefore, the processing accuracy required for the housing 21 that holds the drive piston 23 and the decompression piston 22 can be relaxed to be lower than that of the prior art, and the processing of the housing 21 is facilitated. As a result, the manufacturing cost of the pressure reducing valve 20 can be reduced. By making the housing easier to process, mass production of the pressure reducing valve 20 can be facilitated.

  Further, since the drive piston 23 and the decompression piston 22 are formed separately, the drive piston 23 and the decompression piston 22 can be formed shorter than the conventional piston 3. Further, the contact of the drive piston 23 and the decompression piston 22 with respect to the housing 21 can be suppressed. In other words, it is possible to reduce a non-uniform frictional force acting in the circumferential direction acting on the drive piston 23 and the pressure-reducing piston 22 as compared with a case where the piston 3 according to the prior art is hit with one side. By reducing the non-uniform frictional force in the circumferential direction, the hysteresis of the pressure reducing characteristic of the pressure reducing valve 20 can be made smaller than before.

  Therefore, it is possible to realize the pressure reducing valve 20 that can easily control the pressure reducing valve 20 and can reduce the manufacturing cost.

  Further, by suppressing the contact of the drive piston 23 and the pressure reducing piston 22 with each other, when the pistons 22 and 23 are displaced in the housing 21, the seal members 49 and 52 are contacted with each other and are unevenly worn. Can be suppressed. As a result, the sealing members 49 and 52 can reliably achieve sealing, and the life of the sealing members 49 and 52 can be extended. Thus, since the sealing can be reliably achieved, the pressure reducing valve 20 can prevent the high pressure gas from leaking from the secondary pressure chamber 92 and the back pressure chamber 61 even when used in the high pressure gas.

  Furthermore, according to the pressure reducing valve 20 of the present embodiment, the drive piston 23 is held by the guide bush 34, and the pressure reducing piston 22 is held by the guide portion 43. In the case of the piston 3 according to the related art, the piston 3 is held by the guide bush 34 and the guide portion 43 so as to be displaceable. When the concentricity of the guide bush 34 and the guide portion 43 is low, the contact surface pressure of the piston 3 becomes non-uniform over the entire circumference, and hits the housing 21. As a result, problems such as contact of the seal members 49 and 52 and uneven wear occur. Therefore, in the conventional pressure reducing valve 1 including the piston 3 in which the pressure reducing piston 33 and the drive piston 23 are integrally formed, the guide bush 34 and the guide portion 43 cannot allow a large tolerance of coaxiality, and the housing 2 The required machining accuracy is high.

  In the present embodiment, the drive piston 23 and the decompression piston 22 are formed separately. Therefore, the drive piston 23 displaces the guide bush 34, and the decompression piston 22 displaces the guide portion 43. Even when the coaxiality of the guide bush 34 and the guide portion 43 is low, the pistons 22 and 23 displace the guide bush 34 and the guide portion 43, respectively. Therefore, the contact surface pressure between the decompression piston 22 and the drive piston 23 can be made uniform over the entire circumference, and the contact of the decompression piston 22 and the drive piston 23 with the housing 21 can be suppressed. Therefore, the tolerance of coaxiality between the guide bush 34 and the guide portion 43 can be allowed to be larger than that of the conventional technique, and the processing accuracy required for the housing 21 can be relaxed to be lower than that of the pressure reducing valve 1 of the conventional technique. Processing becomes easy. Thereby, the manufacturing cost of the pressure reducing valve 20 can be reduced. By facilitating the processing of the housing, it becomes possible to further facilitate mass production of the pressure reducing valve 20.

  Further, since the contact surface pressure can be made uniform over the entire circumference in the circumferential direction, the decompression piston 22 and the drive piston 23 can be prevented from hitting the housing 21 in one piece. As a result, the seal members 49 and 52 can achieve the seal without impairing the sealing performance. By forming the decompression piston 22 and the drive piston 23 separately as described above, the housing 21 can be slid without contact with each other even when the guide bush 34 and the guide portion 43 are held at two locations. Can be displaced. As a result, the non-uniform frictional force acting on the decompression piston 22 and the drive piston 23 can be reduced, and the decompression characteristic hysteresis of the decompression valve 20 can be reduced.

  Furthermore, according to the pressure reducing valve 20 of the present embodiment, since the rod 24 and the base rod 25 are formed separately, the tolerance of the coaxiality between the rod 24 and the base rod 25 is allowed to be larger than that of the prior art. Can do. Therefore, the processing accuracy required for the decompression piston 22 holding the rod 24 can be relaxed to be lower than that of the prior art, and the processing of the decompression piston 22 is facilitated. Thus, even if a back pressure chamber is formed between the pressure-reducing piston 22 and the rod 24, the production cost of the pressure-reducing valve 20 can be reduced. Since the processing of the pressure reducing piston becomes easy, the mass production of the pressure reducing valve 20 becomes possible.

  Moreover, since the rod 24 and the base rod 25 are formed separately, the rod 24 and the base rod 25 are formed to be shorter than when they are integrally formed. Thereby, the contact surface pressure of the rod 24 with respect to the decompression piston 22 becomes uniform over the entire circumference in the circumferential direction as compared with the case where the rod 24 is integrally formed. Therefore, the contact of the rod 24 with the decompression piston can be suppressed. As a result, it is possible to reduce the non-uniform frictional force acting on the rod 24 in the circumferential direction and to reduce the hysteresis of the pressure reducing characteristic of the pressure reducing valve, as compared with the case where the rod 24 hits one side.

  According to the pressure reducing valve 20 of the present embodiment, the rod 24 is inserted into the pressure reducing piston 22 and the base rod 25 is held in the fitting recess 73. Since the rod 24 and the base rod 25 are formed separately, even when the coaxiality between the rod 24 and the base rod 25 is low, the contact surface pressure of the rod 24 against the decompression piston 22 is uniform over the entire circumference. become. As a result, the one-sided contact of the rod 24 with respect to the decompression piston 22 can be suppressed. Therefore, the coaxiality tolerance between the rod 24 and the base rod 25 can be allowed to be larger than that of the prior art. As a result, the processing accuracy required for the housing 21 and the decompression piston 22 can be relaxed to a level lower than that of the prior art, and the processing of the decompression piston 22 is facilitated. Since processing is easy in this way, the manufacturing cost of the pressure reducing valve 20 can be reduced even if the back pressure chamber 61 is formed between the pressure reducing piston 22 and the rod 24. Since the processing of the pressure reducing piston becomes easy, the mass production of the pressure reducing valve 20 becomes possible.

  The rod 24 is brought into contact with the support surface 68 by the third spring member 19. Accordingly, the rod 24 is restricted from being displaced in the axial direction, and can be prevented from being detached from the decompression piston 22. Furthermore, by supporting the rod 24, it is possible to suppress the generation of abnormal noise and friction caused by the relative displacement of the rod 24 with respect to the housing 21.

  Further, when the rod 24 and the base rod 25 are integrally formed, the rod 24 and the base rod 25 are held by the fitting recess 73. Therefore, if the coaxiality of the hole 94 through which the fitting recess 73 and the rod 24 are inserted is low, the rod 24 portion The contact surface pressure becomes non-uniform over the entire circumference. As a result, the rod 24 comes into contact with the decompression piston 22. With such contact, the seal member 56 wears unevenly, the sealing performance is impaired, and the life of the seal member 56 is reduced.

  According to the pressure reducing valve 20 of the present embodiment, since the rod 24 and the base rod 25 are formed separately, the concentricity of the fitting recess 73 and the hole 94 through which the rod 24 is inserted is such that the rod 24 and the base 24 are coaxial. Even if it is lower than the case where the rod 25 is integrally formed, the rod 24 is inserted into the decompression piston 22 in a state where the contact surface pressure of the rod 24 against the decompression piston 22 is uniform over the entire circumference. As a result, the rod 24 slides and displaces in the axial direction X without coming into contact with the decompression piston 22. As a result, the uneven frictional force acting on the rod 24 in the circumferential direction can be reduced, and the hysteresis of the pressure reducing characteristic of the pressure reducing valve 20 can be reduced. Further, uneven wear of the seal member 56 can be suppressed, sealing can be reliably achieved, and the life of the seal member 56 can be extended.

  According to the pressure reducing valve 20 of the present embodiment, the support surface 68 of the base rod 25 is formed in a partial spherical shape. Therefore, even when the axis of the base rod 25 is inclined with respect to the axis of the rod 24, the base rod 25 supports the rod 24 without coming into contact with the rod 24. Therefore, the contact surface pressure of the rod 24 with respect to the decompression piston 22 is uniform over the entire circumference. As a result, a non-uniform frictional force acting on the rod 24 in the circumferential direction can be reduced. Thereby, the hysteresis of the pressure reducing characteristic of the pressure reducing valve 20 can be reduced.

  FIG. 3 is a cross-sectional view showing a pressure reducing valve 20A according to the second embodiment. The pressure reducing valve 20A is similar to the pressure reducing valve 20 of the first embodiment, and only different points will be described. The same components are denoted by the same reference numerals and description thereof will be omitted. The pressure reducing valve 20A includes a housing main body 95 and a cap member 96 in the housing 21A. The housing body 95 and the cap member 96 are provided coaxially with each other, and the axes of these axes are provided coaxially with the axis L1 of the pressure reducing valve 20A. The housing body 95 is generally formed in a bottomed cylindrical shape. The housing main body 95 is formed by the main body portion 32A and the base portion 33A. The main body 32A is formed in a bottomed cylindrical shape. A fitting recess 73A that holds the base rod 25 is formed in the bottom 39A of the main body 32A. In the bottom portion 39A, a secondary port 30A that passes through the fitting recess 73A along the axial direction is formed.

  The base 33A is generally formed in a cylindrical shape. The base portion 33A is formed with a flange-like outward convex portion 35A extending outward in the radial direction and extending over the entire circumference in the axial direction from the axial direction one end portion 36A to the axial direction intermediate portion. The outward projecting portion 35A is formed by connecting the open end portion of the main body portion 32A to the outer peripheral edge portion on the side of the other end portion 37 in the axial direction of the base portion 32A. A cap member 96 is screwed into the opening end portion 36A which is one end portion in the axial direction of the base portion 33A. A flange-shaped guide portion 43 that protrudes inward in the radial direction and extends over the entire circumferential direction is formed in the inner peripheral portion of the portion near the axial end portion 36A of the intermediate portion in the axial direction of the base portion 33A. A flange-like base inward convex portion 44 that protrudes inward in the radial direction and extends over the entire circumference in the circumferential direction is formed on the inner peripheral portion of the portion near the other axial end portion 37 of the intermediate portion in the axial direction of the base portion 33A. . Further, a guide bush 34 is fitted and held on the inner peripheral portion of the other axial end portion 37 of the base portion 33A.

The cap member 96 is generally formed in a cylindrical shape. The cap member 96 is formed with a primary port 29A that is inserted along the axis thereof. An annular projecting piece 81 </ b> A is formed at one end 97 in the axial direction of the cap member 96, extending in the entire circumferential direction so as to surround the primary port 29 </ b> A and projecting in a tapered manner in one axial direction. The projecting piece 81 </ b> A is disposed to face the sheet portion 82 formed on the decompression piston 22 in the axial direction X. An annular orifice 83 is formed by the protruding piece 81 </ b> A and the sheet portion 82. A back pressure chamber 61 is formed between the housing main body 95, the cap member 96 and the decompression piston 22. The back pressure chamber 61 has a primary pressure chamber 84 formed on the radially inner side of the orifice 83 and a secondary region 85 formed on the radially outer side of the orifice 83. The primary pressure chamber 84 and the secondary region 85 are connected via an orifice 83. A plurality of communication holes 87A, for example, two communication holes 87A, are formed in the guide portion 43 in order to communicate the secondary side region 85 and the first spring accommodating space 45. Each communication hole 87A is formed by inserting the guide portion 43 in the axial direction X, leaving an equal interval around the axis L1, and 180 degrees in the present embodiment. The outer peripheral portion of the one axial end portion 97 of the cap member 96 is screwed into the inner peripheral portion of the open end portion 38 of the housing in a state where a seal is achieved.

  The base rod 25A is formed with a fourth through hole 98 through which the other axial end portion 74 of the base rod 25A is inserted along the axis L1. The fourth through hole 98 communicates the third through hole 71 and the secondary port 30A.

In the pressure reducing valve 20 configured as described above, the fluid flowing down the primary port 29A is reduced in pressure by passing through the orifice 83 in the same manner as the pressure reducing valve 20 of the first embodiment, so that the secondary pressure is reduced. It flows down into the chamber 92. The liquid flowing down to the secondary pressure chamber 92 is discharged from the secondary port 30 </ b> A through the fourth through hole 98. Accordingly, the pressure of the fluid discharged from the primary port 29A, the fluid in the primary pressure chamber 84, and the fluid in the back pressure chamber 61 becomes the primary pressure p1 as in the pressure reducing valve 20 of the first embodiment, and the secondary pressure chamber The pressure of the fluid 92 and the fluid discharged from the secondary port 30A becomes the secondary pressure p2. The operation of the pressure reducing valve 20A is the same as that of the pressure reducing valve 20 of the first embodiment, and the description thereof is omitted.

  Below, the effect which pressure reducing valve 20A of this embodiment shows is explained. According to the pressure reducing valve 20A of the present embodiment, the third and fourth through holes 71 and 98 are inserted from the other axial end 74 of the base rod 25A to the first through hole 69. Accordingly, a hole can be formed along the axis from the other axial end portion 74 of the base rod 25A to the other axial direction X2, and it is easy to form the third and fourth through holes 71 and 98, thereby eliminating processing waste. be able to.

  The pressure reducing valve 20A of the present embodiment has the same effects as the pressure reducing valve 20 of the first embodiment.

  FIG. 4 is a cross-sectional view showing a pressure reducing valve 20B according to the third embodiment. FIG. 5 is a cross-sectional view of the decompression piston 22B as seen by cutting along a cross-sectional line II. The pressure reducing valve 20B is similar to the pressure reducing valve 20 of the first embodiment, and only different points will be described. The same components are denoted by the same reference numerals and description thereof will be omitted. The first housing 28B further includes a port portion 99 that is generally formed in a bottomed cylindrical shape. The port portion 99, the main body portion 32, and the base portion 33 are provided coaxially with each other, and the axes of these axes are provided coaxially with the axis L1 of the pressure reducing valve 20B. The port portion 99 has an opening end portion 100 connected to one end portion 36 in the axial direction of the base portion, and is provided so as to protrude from the one axial end portion 36 of the base portion 33 to the other axial direction X2. The port portion 99 is formed so that the inner peripheral portion thereof has a larger diameter than the inner peripheral portion of the axial end portion 36 of the base portion 33, that is, the inner peripheral portion of the guide portion 43.

  A primary port 29 </ b> B is formed in the bottom portion 101 of the port portion 99 along the axis. The bottom portion 101 is formed with an annular projection piece 81B that extends in the entire circumferential direction so as to surround the primary port 29B and projects in a tapered manner in one axial direction. The decompression piston 22 is provided with a sheet portion 82 so as to face the protruding piece 81B. An orifice 83 is formed by the protruding piece 81 </ b> B and the sheet portion 82. Further, the port portion 99 is formed with a plurality of secondary ports 30 </ b> B inserted through the outer peripheral portion thereof in the radial direction. The secondary ports 30B are formed at equal intervals in the circumferential direction on the outer peripheral portion of the port portion 99, specifically, at intervals of 180 degrees. In the present embodiment, two secondary ports 30 </ b> B are formed on the outer peripheral portion of the port portion 99.

A back pressure chamber 61 is formed in the port portion 99 thus provided. The back pressure chamber 61 has a primary pressure chamber 84 radially inward of the orifice 83 and a secondary region 85 radially outward of the orifice 83. The primary pressure chamber 84 and the secondary side region 85 are connected via an orifice 83. The primary port 29 </ b> B is continuous with the primary pressure chamber 84, and the secondary port 30 </ b> B is continuous with the secondary side region 85.

  The decompression piston 22B is generally formed in a bottomed cylindrical shape. The decompression piston 22B has two flat portions 102 that are parallel to the axis L1 and parallel to each other on the outer peripheral portion of the decompression piston 22B from the one end portion 40 in the axial direction to the portion other than the other end portion 41 in the axial direction. . In the present embodiment, the two flat portions 102 are two virtual planes S1 that are perpendicular to the radial direction, and are formed by cutting away portions of the outer periphery of the decompression piston that are radially outward from the two virtual planes S1. The The two virtual planes S1 are two planes that face each other and are parallel to each other. When formed in this way, two flat portions 102 that are parallel to each other are formed on the outer peripheral portion of the decompression piston 22B, and an arc portion 103 is formed in the remaining portion.

When the pressure-reducing piston 22B formed in this way is inserted into the guide portion 43, the flat portion 102 of the pressure-reducing piston 22B and the inner peripheral portion of the guide portion 43 are disposed at an interval in the radial direction. Thus, a slit-like communication hole 87B extending in the axial direction is formed between the flat portion 102 of the decompression piston 22B and the inner peripheral portion of the guide portion 43. The communication hole 87 </ b> B communicates the secondary region 85 of the back pressure chamber 61 and the first spring accommodating space 45.

  The second housing 31B is formed with a substantially cylindrical recess 104 that is recessed in the other axial direction. The recess 104 and the first housing 28B are provided coaxially with each other, and the axis of the recess 104 is provided coaxially with the axis L1 of the pressure reducing valve 20B. The concave portion 105 forming the concave portion 104 is formed so that the portion on the axial end portion 36 side of the base portion 33 and the port portion 99 are inserted, and the portion on the axial end portion 36 side of the base portion 33 can be screwed. . Specifically, the concave portion 105 has a large-diameter portion 106 at the axially intermediate portion, an intermediate-diameter portion 107 at the axial end portion side that is the opening end portion, and an axially other end portion that is the bottom portion. Small diameter portions 108 are respectively formed on the side portions. The large diameter portion 106 is formed to have a larger diameter than the medium diameter portion 107, and the medium diameter portion 107 is formed to have a larger diameter than the small diameter portion 108. The intermediate diameter portion 107 of the recess 105 is inserted into a portion of the base portion 33 on the axial direction one end portion 36 side, and this portion is screwed. A portion of the base portion 33 on the axial end portion 36 side is screwed to the intermediate diameter portion 107 in a state where a seal is achieved between the outer peripheral portion and the intermediate diameter portion 107 over the entire circumference in the circumferential direction.

  The bottom portion 101 of the port portion 99 is formed in the small diameter portion 108 of the recess 105 so as to be insertable. The bottom portion 101 of the port portion 99 is inserted into the small diameter portion 107 in a state where a seal is achieved between the outer peripheral portion and the small diameter portion 107 over the entire circumference. In this state, the bottom portion of the small diameter portion 107 and the bottom portion 101 of the port portion 99 are arranged to face each other with a gap in the axial direction X. As a result, the disc-shaped primary port communication space 109 is formed between the small-diameter portion 107 and the port portion 99. The primary port communication space 109 is connected to the primary port 29B. A first flow path 110 is formed in the second housing 31B so as to be inserted from the bottom of the small diameter portion 107 along the axis. The first flow path 110 communicates with the primary port communication space 109, and communicates with the primary port 29 </ b> B through the primary port communication space 109.

  In a state where the first housing 28B is screwed into the concave portion 105, the inner peripheral portion of the large-diameter portion 106 and the outer peripheral portion of the port portion 99 are disposed to face each other and are spaced apart in the radial direction. An annular secondary port communication space 111 is formed between the inner peripheral portion of the large diameter portion 106 and the outer peripheral portion of the port portion 99. The secondary port communication space 111 is connected to the secondary port 30B. In the second housing 31B, a second flow path 112 extending outward in the radial direction from the inner peripheral portion of the large diameter portion 106 is formed. The second flow path 112 communicates with the secondary port communication space 111, and communicates with the secondary port 30 </ b> B through the secondary port communication space 111.

  In such a pressure reducing valve, the fluid flows from the first flow path 110 to the primary port 29 </ b> B through the primary port communication space 109. The fluid flowing down to the primary port 29B is depressurized by the orifice 83 in the same manner as the pressure reducing valve 20 of the first embodiment, and is transferred from the secondary port 30A to the second flow path 112 via the secondary port communication space 111. Discharged. About operation | movement of a pressure-reduction valve, it is the same as that of 1st Embodiment, The description is abbreviate | omitted.

  Below, the effect which pressure reducing valve 20B of this embodiment has is explained. According to the pressure reducing valve 20B of the present embodiment, by providing the port portion 99 in the base portion 33, the protruding piece 81B, the primary port 29B, and the secondary port 30B are formed in the first housing 28B. As a result, the pressure reducing valve 20B can be interposed in the flow path simply by screwing the first housing 28B into the second housing 30B. Further, it is not necessary to form the protruding piece 81B on the second housing 30B such as a gas tank, and the processing of the second housing 29B is facilitated, so that versatility and combined use can be improved. As a result, the manufacturing cost of the pressure reducing valve 20B can be reduced, and the pressure reducing valve 20B can be mass-produced.

According to the pressure reducing valve 20B of the present embodiment, the slit-shaped communication hole 87B is formed between the outer peripheral portion of the pressure reducing valve 20B and the outer peripheral portion of the guide portion 43. The communication hole 87 </ b> B communicates the secondary region 85 of the back pressure chamber 61 and the first spring accommodating space 45. Therefore, it is not necessary to form a hole like the communication hole 87 of the pressure reducing valve 20 of the first embodiment in the base portion 33. This makes it possible to increase the mechanical strength of the base portion 33, that is, the mechanical strength of the first housing 28B, as compared with the pressure reducing valve 20 of the first embodiment. In addition, by increasing the mechanical strength of the base portion 33 in this way, the port portion 99 can be provided in the base portion 33.

  Further, a port portion 99 in which the primary port 29B and the secondary port 30B are formed is integrally provided in the base portion 33. Therefore, if the communication hole 87B is formed in the base portion 33 and the port portion 99, the mechanical strength of the base portion 33 and the port portion 99 is reduced. Further, it is difficult to secure a space for forming the communication hole 87B in the port portion 99. As in the present embodiment, the communication hole 87B is formed between the outer peripheral portion of the decompression piston 22 and the inner peripheral portion of the guide portion 43, thereby overcoming the problems of lowering mechanical strength and ensuring space. Forming the primary port 29B, the secondary port 30B, and the protruding piece 81B in the 1 housing 28B can be realized.

  FIG. 6 is an enlarged cross-sectional view of a portion where the base rod 25 and the rod 24C of the second form abut and support each other. In the rod 24C of the second form, a rod recess 113 is formed along the axis at the other end 41C in the axial direction. The rod recess 113 is formed in a conical shape such that the other axial direction X2 side is inclined inward in the radial direction toward the other axial direction X2. The rod recess 113 is formed so that a part of one end of the base rod 25 in the axial direction, that is, a part of the small diameter part 65 can be fitted. The support surface 68 of the base rod 25 is in contact with a tapered portion of the rod recess 114 that forms the rod recess 113. The support surface 68 is formed in a partial spherical shape such that the contact surface 115 that contacts the rod recess 114 is annular.

  When the base rod 25 and the rod 24C are formed in this manner, even when the coaxiality of the base rod 25 and the rod 24C is low, for example, when the axis of the base rod 25 is inclined with respect to the axis of the rod 24C, Since the support surface 68 has a partially spherical shape, the contact surface 115 has an annular shape. The contact surface pressure is applied from the contact surface 115 to the rod concave portion 114 so as to be perpendicular to the rod concave portion 114 and uniformly over the entire circumference. Therefore, the sum total of the circumferential circumferences of the component forces of the radial component of the contact surface pressure applied to the rod recess 114 is substantially zero, and the pressing force in the other axial direction X2 is applied from the contact surface 115 to the rod recess 114. Is granted. As a result, a uniform contact surface pressure is applied to the outer peripheral portion of the rod 24C over the entire circumference in the circumferential direction, thereby suppressing one-side contact. As a result, the non-uniform frictional force acting on the rod 24C in the circumferential direction can be reduced, and the hysteresis difference in the override characteristics of the pressure reducing valve 20 can be reduced.

  By suppressing the contact of the rod 24 </ b> C in this way, a uniform contact surface pressure is applied from the outer periphery of the rod 24 </ b> C to the inner periphery of the decompression piston 22 over the entire circumference. Thereby, the one-sided contact of the decompression piston 22 with respect to the housing 21 can also be suppressed. When the one-side contact is suppressed in this way, uneven wear of the seal members 49, 52, 56 provided on the rod 24 and the decompression piston 22 can be suppressed, and the life of the seal members 49, 52, 56 can be extended.

  FIG. 7 is an enlarged cross-sectional view showing a portion where the base rod 25D and the rod 24 of the second embodiment are in contact with each other. The support surface 68D of the base rod 25D is formed flat. The support surface 68D abuts the other end 41 in the axial direction of the rod 24 and applies a pressing force in one axial direction X1 against the spring force applied by the third spring member 19 to support the rod 24. Yes. By flattening the support surface 68D, complicated processing is not required, the processing of the base rod 25D is facilitated, the manufacturing cost of the pressure reducing valve 20 can be reduced, and mass production of the pressure reducing valve 20 becomes possible. Become. Further, since the pressure reducing valve 20 is configured such that the tolerance of the coaxiality is larger than that of the prior art, the pressure reducing valve 20 can be realized without causing a large hysteresis even when the support surface 68 is formed flat. Can do.

It is sectional drawing which shows the pressure reducing valve 20 of the 1st Embodiment of this invention. It is a figure which expands and shows the rod 24 and the base rod 25. It is sectional drawing which shows 20 A of pressure reducing valves of 2nd Embodiment. It is sectional drawing which shows the pressure-reduction valve 20B of 3rd Embodiment. It is sectional drawing which cut | disconnected the decompression piston 22B by cut | disconnecting by sectional line II. It is sectional drawing which expands and shows the part which the base rod 25 and the rod 24C of 2nd form contact | abut. It is sectional drawing which expands and shows the part which base rod 25D and rod 24 of 2nd form contact | abut. It is sectional drawing which simplifies and shows typically the pressure-reduction valve 1 of a prior art.

Explanation of symbols

18 Spring means 20 Pressure reducing valve 21 Housing 22 Pressure reducing piston 23 Drive piston 24 Rod 25 Base rod 26 First spring member 27 Second spring member 29 Primary port 30 Secondary port
61 Back pressure chamber 68 Support surface 84 Primary pressure chamber 92 Secondary pressure chamber 93 Secondary pressure receiving surface

Claims (2)

A housing in which a primary port and a secondary port are formed, and a housing having a guide bush formed at one end in the axial direction of the housing and fitted into the other end in the axial direction ;
A pressure-reducing piston held in a housing by a guide part so as to be displaceable , receiving a primary pressure at one end thereof, adjusting the opening degree of the primary port by the displacement, and a primary pressure chamber and a secondary port connected to the primary port a pressure reducing piston off specification within the housing to a secondary pressure chamber communicating with,
A drive piston which is displaceably held by a guide bush in the housing, in direct contact to the other end portion opposite to displace in conjunction with vacuum pistons and the end portion for receiving a primary pressure reduced pressure piston and Bei obtain drive piston of the secondary pressure receiving surface for receiving the secondary pressure from the fluid in the secondary pressure chamber,
Spring means for applying a spring force against the secondary pressure to at least one of the decompression piston and the drive piston ;
A first rod that is inserted into the pressure reducing piston so as to be displaceable and forms a back pressure chamber that is held at the primary pressure between the pressure reducing piston and the pressure reducing piston;
A pressure reducing valve, comprising: a second rod held by a housing, the second rod supporting the first rod and applying a pressing force against the primary pressure applied to the first rod . The second rod, the vacuum valve according to claim 1, wherein the support surface for supporting the first rod, characterized in that it is formed in the partially spherical shape.

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