Pressure reducing valve

Abstract

This pressure reducing valve includes: a casing including a passage; a valve body movably housed in the casing and adjusting an opening degree of the passage; a first biasing member for biasing the valve body in a closing direction; a stem housed in the casing so as to be movable and abutting on the valve body; and a second biasing member for biasing the valve body in an opening direction so as to resist secondary pressure via the stem. The second biasing member is a plate-shaped spring and extends laterally from the stem.

Description

Pressure reducing valve

[0001] The present disclosure relates to a pressure reducing valve that reduces the pressure of gas and outputs it.

[0002] As a pressure reducing valve for gases such as compressed natural gas and hydrogen gas, for example, a pressure reducing valve as disclosed in Patent Document 1 is known. In the pressure reducing valve of Patent Document 1, the biasing force of a compression coil spring and the secondary pressure act on a piston so as to resist each other. The piston adjusts the opening of a valve passage by pushing a valve element with a force corresponding to the secondary pressure.

[0003] JP 2012-093809 A

[0004] In the pressure reducing valve of Patent Document 1, the piston is biased by a compression coil spring, so the size of the pressure reducing valve, particularly its axial length, becomes large.

[0005] Therefore, an object of the present disclosure is to provide a pressure reducing valve that can be made smaller.

[0006] The pressure reducing valve of the present disclosure comprises a casing including a passage, a valve body movably housed in the casing and adjusting the opening of the passage, a first biasing member urging the valve body in a closing direction, a stem movably housed in the casing and abutting the valve body, and a second biasing member urging the valve body via the stem in an opening direction against a secondary pressure, the second biasing member being a plate-shaped spring extending laterally from the stem.

[0007] According to the pressure reducing valve of the present disclosure, the second biasing member is a plate-shaped spring extending laterally from the stem, which allows the axial dimension of the pressure reducing valve to be reduced.

[0008] According to the present disclosure, miniaturization is possible.

[0009] The above and other objects, features, and advantages of the present disclosure will become apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings.

[0010] Fig. 3 is a cross-sectional view showing a pressure reducing valve according to an embodiment of the present disclosure. Fig. 4 is a cross-sectional view showing a state in which a valve body is seated on a valve seat in the pressure reducing valve of Fig. 1. Fig. 5 is an enlarged cross-sectional view showing an enlarged view of the periphery of a stem and a leaf spring of the pressure reducing valve of Fig. 1. Fig. 6 is an enlarged cross-sectional view showing an enlarged view of an area X in the pressure reducing valve of Fig. 3. Fig. 7 is a cross-sectional view showing a gas flow in the pressure reducing valve of Fig. 1.

[0011] A pressure reducing valve 1 according to an embodiment of the present disclosure will be described below with reference to the drawings. Note that the concepts of directions used in the following description are used for convenience of explanation and do not limit the orientation of the configuration of the present disclosure to those directions. Furthermore, the pressure reducing valve 1 described below is merely one embodiment of the present disclosure. Therefore, the present disclosure is not limited to the following embodiment, and additions, deletions, and modifications are possible within the scope of the present disclosure.

[0012] The pressure reducing valve 1 shown in Fig. 1 is used to reduce the pressure of gases such as compressed natural gas and hydrogen gas to operating pressure or atmospheric pressure. The pressure reducing valve 1 includes a casing 10, a valve body 11, a coil spring 12, a stem 13, and a leaf spring 14. In the pressure reducing valve 1 of this embodiment, the casing 10, the valve body 11, the coil spring 12, the stem 13, and the leaf spring 14 are arranged along a predetermined axis L1.

[0013] <Casing> The casing 10 has a passage 15. The casing 10 also has an accommodation space 16. The casing 10 further has a primary side passage 17, a valve element chamber 18, a guide portion 19, and a secondary side passage 20. The primary side passage 17 has a primary port 17a, and gas is input through the primary port 17a. The primary side passage 17 is also connected to the valve element chamber 18. The valve element chamber 18 is connected to the guide portion 19 via a passage 15. The guide portion 19 is connected to the secondary side passage 20 via a secondary chamber 36 of the accommodation space 16, which will be described in detail later. The secondary side passage 20 has a secondary port 20a, and gas flows through the secondary port 20a. More specifically, the casing 10 includes a joint portion 21, a valve element housing 22, a seat 23, a casing main body 24, and a cover 25. The casing 10 also includes a filter 26 .

[0014] The joint portion 21 includes a primary passage 17, a housing attachment portion 28, and a seat attachment portion 29. The primary passage 17, the housing attachment portion 28, and the seat attachment portion 29 are formed along the axis L1 in the joint portion 21. That is, the joint portion 21 is formed cylindrically, and the primary passage 17, the housing attachment portion 28, and the seat attachment portion 29 form an inner hole of the joint portion 21. The primary passage 17, the housing attachment portion 28, and the seat attachment portion 29 are formed in this order from one axial end in the joint portion 21. A primary port 17a is formed at one axial end of the joint portion 21, and the seat attachment portion 29 opens at the other axial end of the joint portion 21. The axial direction is the direction in which the axis L1 extends. The housing attachment portion 28 is formed with a larger diameter than the primary passage 17. The seat attachment portion 29 is formed with a larger diameter than the housing attachment portion 28. Furthermore, for example, a pipe (not shown) is connected to one axial side portion of the joint portion 21. A nut is formed in the middle portion of the joint portion 21. Furthermore, a male thread is formed in the other axial side portion of the joint portion 21.

[0015] The valve element 11, which will be described in detail later, is inserted through the valve element housing 22 so as to be slidable in the axial direction. The valve element housing 22 is accommodated in a housing mounting portion 28 with the valve element 11 inserted therethrough. More specifically, the valve element housing 22 is cylindrical. A filter 26 is attached to one axial end of the valve element housing 22. The filter 26 is attached to the valve element housing 22 so as to cover an opening on one axial side of the valve element housing 22. The filter 26 captures contaminants and the like contained in the gas flowing from the primary-side passage 17. The inner bore of the valve element housing 22 has a middle portion with a smaller diameter than the remaining portion. The portion of the inner bore of the valve element housing 22 on the other axial side of the middle portion forms a valve element chamber 18. The valve element 11 is slidably inserted through the valve element chamber 18.

[0016] The seat 23 is attached to the seat attachment portion 29 of the joint portion 21. More specifically, the seat 23 is fitted into the seat attachment portion 29. The seat 23 is formed, for example, in an annular shape and has a through hole 23a. The through hole 23a is formed along the axis L1. The valve body 11 is seated on the seat 23, thereby closing the through hole 23a. The seat 23 is made of, for example, a synthetic resin. However, the seat 23 may also be made of a metal such as stainless steel.

[0017] The casing body 24 has a joint mounting portion 30, a communication hole 31, a guide portion 19, the accommodation space 16, a cover mounting portion 33, and a secondary-side passage 20. The joint mounting portion 30, the communication hole 31, the guide portion 19, the accommodation space 16, and the cover mounting portion 33 are formed along the axis L1. More specifically, the joint mounting portion 30, the communication hole 31, the guide portion 19, the accommodation space 16, and the cover mounting portion 33 are formed in the casing body 24 in that order from one axial end. The joint mounting portion 30 and the cover mounting portion 33 are open at one and the other axial ends of the casing body 24, respectively.

[0018] The other axial side portion of the coupling part 21 is inserted into and attached to the coupling attachment part 30. Explaining in more detail, the coupling attachment part 30 has an internal thread formed therein. The other axial side portion of the coupling part 21 is screwed into the coupling attachment part 30 in a sealed state. Explaining in even more detail, the coupling part 21 has a seat 23 attached to the seat attachment part 29 in a state in which the seat 23 protrudes slightly, and is screwed into the coupling attachment part 30 so that the seat 23 is pressed against the bottom of the coupling attachment part 30. Note that the coupling part 21 does not necessarily have to be screwed into the coupling attachment part 30, and may be fixed to the coupling attachment part 30 in other ways, such as by fastening or fitting.

[0019] The communication hole 31 is connected to the joint mounting portion 30 and has a smaller diameter than the joint mounting portion 30. More specifically, the communication hole 31 is connected to the through hole 23a of the sheet 23 and together with the through hole 23a forms the passage 15. In this embodiment, the communication hole 31 has the same diameter as the through hole 23a.

[0020] The guide portion 19 is connected to the communicating hole 31 and has a larger diameter than the communicating hole 31. The stem 13, which will be described in detail later, is slidably inserted into the guide portion 19, and guides the stem 13 to slide in the axial direction. The accommodation space 16 is connected to the guide portion 19 and has a larger diameter than the guide portion 19. In this embodiment, the accommodation space 16 has a larger diameter than the joint attachment portion 30, the communicating hole 31, and the guide portion 19. The cover attachment portion 33 is formed on the other axial side of the accommodation space 16 and has a larger diameter than the accommodation space 16. As a result, a step 33a is formed around the entire periphery of the opening of the accommodation space 16.

[0021] The secondary-side passage 20 is formed at a distance radially outward from the axis L1. In this embodiment, the secondary-side passage 20 is formed radially outward from the guide portion 19. The secondary-side passage 20 is connected to the accommodation space 16. As described above, the secondary-side passage 20 has the secondary port 20a, which opens at, for example, the side surface of the casing body 24.

[0022] The cover 25 is attached to the cover mounting portion 33. More specifically, the cover 25 has a convex portion 25a that protrudes to one axial side. The convex portion 25a is fitted to the cover mounting portion 33 in a sealed state, thereby closing the accommodation space 16. The cover 25 is fastened to the casing main body 24, for example, by a fastening member (not shown). The cover 25 may be attached to the casing main body 24 by a method other than fastening with a fastening member, for example, by a screwing method in which the cover 25 is screwed onto the casing main body 24. One axial end face of the cover 25, i.e., the end face of the convex portion 25a, has an outer peripheral edge that protrudes to one axial side along the entire circumferential direction. The cover 25 also has an air vent hole 25b formed along the axis L1.

[0023] <Valve Disk> The valve disk 11 is movably housed in the casing 10. The valve disk 11 adjusts the opening of the passage 15 by changing its position in response to the secondary pressure. In this embodiment, the valve disk 11 is a bottomed cylindrical member. The inner bore of the valve disk 11 is open at one axial end. The tip end portion of the valve disk 11 on the other axial end is tapered (frustum-shaped in this embodiment). The tip end portion of the valve disk 11 is further formed with multiple through passages 11a. The through passages 11a extend from the inner bore of the valve disk 11 to the side surface of the tip end portion (the tapered surface in this embodiment). The one axial end portion of the valve disk 11 is recessed radially inward along the entire circumferential direction. The valve disk 11 is made of a metal such as stainless steel. However, if the seat 23 is made of a metal such as stainless steel, the valve disk 11 is molded from a synthetic resin. When the seat 23 is made of synthetic resin, the valve body 11 may be made of metal. Also, both the valve body 11 and the seat 23 may be made of synthetic resin or metal.

[0024] As described above, the valve element 11 is axially slidably inserted through the valve element housing 22. The inner bore of the valve element 11 is connected to the primary passage 17 via the other axial side of the inner bore of the valve element housing 22 and the filter 26. As described above, the tip end portion of the valve element 11 is formed in a truncated cone shape, forming an annular passage 22a between the valve element 11 and the valve element housing 22. The inner bore of the valve element 11 is connected to the annular passage 22a via a through passage 11a. As shown in FIG. 2 , the valve element 11 is seated on the seat 23 by moving in the other axial direction, which is an example of a closing direction (i.e., a direction in which the passage 15 is closed). This closes the passage 15. On the other hand, the valve element 11 is separated from the seat 23 by moving in the one axial direction, which is an example of an opening direction (i.e., a direction in which the passage 15 is opened). This opens the passage 15. This connects the annular passage 22a to the passage 15. The valve element 11 adjusts the opening of the passage 15 by moving toward or away from the seat 23 (i.e., moving in the axial direction).

[0025] <Coil Spring> The coil spring 12, which is an example of a first biasing member, biases the valve element 11 in the other axial direction. The coil spring 12 is, for example, a compression coil spring. The coil spring 12 is mounted on the valve element 11. More specifically, the coil spring 12 is mounted on a recessed portion at one axial end of the valve element 11. This reduces the axial dimension of the pressure reducing valve 1. One end of the coil spring 12 abuts against the valve element 11, and the other end abuts against an intermediate portion of the valve element housing 22. This biases the valve element 11 in the other axial direction by the coil spring 12. Note that the coil spring 12 does not necessarily have to be mounted on the valve element 11, and may abut against one axial end of the valve element 11.

[0026] As shown in FIG. 3 , the stem 13 is movably housed in the casing 10. More specifically, the stem 13 is slidably guided in the axial direction within the casing 10. In this embodiment, the stem 13 is slidably inserted into a guide portion 19 of the casing body 24. The stem 13 also abuts against the valve element 11. More specifically, the stem 13 has an abutment portion 13a on one axial side (i.e., the tip side). The abutment portion 13a is elongated and protrudes from the guide portion 19 through the passage 15 into the valve element chamber 18. The abutment portion 13a has a smaller diameter than the passage 15. Therefore, gas flows around the abutment portion 13a toward the guide portion 19. The abutment portion 13a also abuts against the valve element 11 in the valve element chamber 18. In this embodiment, the tip of the abutment portion 13a abuts against the tip of the valve element 11.

[0027] On the other hand, the stem 13 has a sliding portion 13b on the other axial side (i.e., the base end side). A plurality of communication passages 13c are formed on the outer peripheral surface of the sliding portion 13b. The communication passages 13c are arranged at intervals in the circumferential direction on the outer peripheral surface of the sliding portion 13b. The communication passages 13c may be formed on the inner peripheral surface of the guide portion 19 instead of the outer peripheral surface of the sliding portion 13b. The communication passages 13c extend from one end to the other end of the sliding portion 13b.

[0028] The sliding portion 13b is fitted into the guide portion 19 so as to be slidable in the axial direction, and is guided in the axial direction by the guide portion 19. The sliding portion 13b is disposed away from the bottom surface of the guide portion 19 in the other axial direction. Therefore, an annular passage 19a is formed around the abutting portion 13a between the sliding portion 13b and the bottom surface of the guide portion 19. The annular passage 19a is connected to the passage 15, and is also connected to the accommodation space 16 (more specifically, the secondary chamber 36, which will be described later in detail) via the aforementioned multiple communication passages 13c.

[0029] A leaf spring 14, an example of a second biasing member, is attached to the stem 13. In this embodiment, the leaf spring 14 abuts against the base end surface of the stem 13, as described below. However, the leaf spring 14 may be fixed to the stem 13 by welding or the like. The leaf spring 14 generates a restoring force corresponding to displacement. The leaf spring 14 moves the stem 13 by the generated restoring force. The leaf spring 14 biases the stem 13 in one axial direction, thereby moving the valve body 11 in one axial direction. The leaf spring 14 is, for example, a plate-shaped metal member (in this embodiment, a member made of SUS or an alloy such as SUS304CSP). The leaf spring 14 is a plate member having a solid circular shape when viewed in the axial direction. More specifically, the leaf spring 14 is formed in a convex shape in one axial direction. That is, the leaf spring 14 is formed in a convex cross section with a central portion 14a protruding in one axial direction.

[0030] More specifically, the central portion 14a of the leaf spring 14 has a diameter larger than the outer diameter of the valve body 11 and is flat. The outer edge portion 14b of the leaf spring 14 is also flat. Furthermore, the leaf spring 14 has a tapered portion 14c connecting the outer edge portion 14b and the central portion 14a, which is formed as follows. That is, the tapered portion 14c is tapered as shown in FIG. 4. In this embodiment, the tapered portion 14c is tapered at multiple angles. More specifically, the outer edge portion 14d and the central portion 14e of the tapered portion 14c have different taper angles α and β. That is, the taper angle β of the central portion 14e is more acute than the taper angle α of the outer edge portion 14d.

[0031] The leaf spring 14 biases the valve element 11 in one axial direction via the stem 13 so as to resist the secondary pressure. The biasing force of the leaf spring 14 causes the valve element 11 to move in one axial direction. The leaf spring 14 is provided in the casing 10. More specifically, the leaf spring 14 is housed in the accommodation space 16. The leaf spring 14 extends further to the side than the stem 13 when viewed in the axial direction. The leaf spring 14 also divides the accommodation space 16 into a secondary chamber 36 and an open space 35.

[0032] The secondary chamber 36 is a space into which the secondary pressure is introduced and is formed to face the leaf spring 14. In this embodiment, the secondary chamber 36 is a space on one axial side of the leaf spring 14 in the accommodation space 16. As described above, the secondary chamber 36 is connected to the passage 15 via the multiple communication passages 13c. The secondary pressure, which is reduced by the valve body 11 adjusting the opening of the passage 15, is introduced into the secondary chamber 36 through the passage 15 and the multiple communication passages 13c. The leaf spring 14 faces the secondary chamber 36. Therefore, the leaf spring 14 receives the secondary pressure in a direction against the biasing force of the leaf spring 14. As described above, the secondary chamber 36 is connected to the secondary-side passage 20, and gas flows into the secondary-side passage 20 through the secondary chamber 36.

[0033] The open space 35 is located on the axially opposite side of the secondary chamber 36 across the leaf spring 14. The open space 35 is connected to the atmosphere via the atmosphere vent hole 25b of the cover 25. The open space 35 draws in and exhausts air via the atmosphere vent hole 25b. This allows elastic deformation of the leaf spring 14 without increasing the internal pressure of the open space 35.

[0034] Furthermore, the leaf spring 14 seals the open space 35 and the secondary chamber 36. More specifically, the leaf spring 14 is provided in the casing 10 by being sandwiched between the casing main body 24 and the cover 25. In this embodiment, the outer edge portion 14b of the leaf spring 14 is sandwiched in a sealed state over the entire circumferential direction between the step portion 33a of the casing main body 24 and the outer peripheral edge portion of the convex portion 25a of the cover 25. In this way, the leaf spring 14 is provided in the casing 10 so as to divide the accommodation space 16 into the open space 35 and the secondary chamber 36 and to seal the open space 35 and the secondary chamber 36.

[0035] As described above, the leaf spring 14 is formed in a convex shape in one axial direction, and the central portion 14a of the leaf spring 14 abuts against the base end surface of the stem 13. The stem 13 abuts against the valve body 11 as described above. The valve body 11 is also biased in the other axial direction by the coil spring 12. Therefore, the stem 13 is pressed in the other axial direction by the valve body 11, and the leaf spring 14 is further pressed in the other axial direction by the stem 13. That is, the leaf spring 14 receives the biasing force of the coil spring 12 in the other axial direction via the valve body 11 and the stem 13. The leaf spring 14 biases the stem 13 in one axial direction against the biasing force of the coil spring 12, and biases the valve body 11 in one axial direction via the stem 13.

[0036] <Operation of Pressure Reducing Valve> In the pressure reducing valve 1, gas at primary pressure flows in from the primary port 17a, as shown by arrow A in FIG. 5 . The inflowing gas passes through the primary-side passage 17 and is guided to the filter 26. The filter 26 captures contaminants contained in the gas. The gas is then guided to the valve chamber 18 of the valve body housing 22, and then through the inner hole of the valve body 11 and the multiple through-passages 11a to the annular passage 22a. The gas is then guided from the annular passage 22a through the passage 15 to the annular passage 19a. The aperture of the passage 15 is adjusted by the valve body 11. As a result, the secondary pressure is adjusted to a pressure corresponding to the aperture of the passage 15. The gas is also guided from the annular passage 19a through the multiple communication passages 13c to the secondary chamber 36, and then from the secondary chamber 36 through the secondary-side passage 20 to flow out of the secondary port 20a.

[0037] In the pressure reducing valve 1 through which gas flows in this manner, the valve element 11 changes its position in response to the secondary pressure to adjust the degree of opening of the passage 15. That is, the valve element 11 is subjected to the biasing forces of the coil spring 12 and the leaf spring 14 in opposing directions, and the leaf spring 14 is also subjected to the secondary pressure in the other axial direction. Therefore, the valve element 11 moves to a position where the biasing forces of the coil spring 12, the leaf spring 14, and the secondary pressure are balanced. As a result, the valve element 11 moves to a position in response to the secondary pressure to adjust the degree of opening of the passage 15, and the secondary pressure is maintained at a predetermined pressure.

[0038] At this time, the leaf spring 14 elastically deforms as follows. That is, the taper angle β of the center portion 14e of the leaf spring 14 is acuter than the taper angle α of the outer edge portion 14d. Therefore, the leaf spring 14 can move the center portion 14a parallel to the axial direction while its outer edge is clamped. More specifically, the tapered portion 14c of the leaf spring 14 elastically deforms while changing the relative angle between the outer edge portion 14d and the center portion 14e. The tapered portion 14c then moves the center portion 14a parallel. Therefore, the leaf spring 14 can abut the base end surface of the stem 13 and the center portion 14a in a flat state. This prevents the stem 13 from making uneven contact with the leaf spring 14. The tapered portion 14c does not necessarily have to have different taper angles between the outer edge portion 14d and the center portion 14e, and may be formed with a single taper angle.

[0039] Furthermore, in the cover 25, the outer peripheral edge of the convex portion 25a protrudes toward one axial direction along the entire circumferential direction. That is, the convex portion 25a is recessed radially inward from the outer peripheral edge. Therefore, when the leaf spring 14 bends toward the other axial direction, the outer peripheral portion 14b is prevented from hitting the convex portion 25a. This ensures space for the leaf spring 14 to bend. That is, the inner portion of the outer peripheral portion 14b can bend toward the convex portion 25a. Therefore, the height of the leaf spring 14 in the pressure reducing valve 1 can be further reduced.

[0040] In the pressure reducing valve 1 of this embodiment, the leaf spring 14 is a plate-shaped spring that extends laterally from the stem 13. Therefore, the axial dimension of the pressure reducing valve 1 can be reduced.

[0041] Furthermore, in the pressure reducing valve 1 of this embodiment, the secondary chamber 36 is formed to face the leaf spring 14. Therefore, the leaf spring 14 receives the secondary pressure in the secondary chamber 36 and moves the valve element 11 to a position according to the secondary pressure via the stem 13. This adjusts the opening of the passage 15 according to the secondary pressure. In conventional pressure reducing valves, a compression coil spring biases the stem via a pressure-receiving member, but in the pressure reducing valve 1, the leaf spring 14 can directly bias the stem 13. Therefore, the pressure-receiving member that receives the secondary pressure can be omitted in the pressure reducing valve 1, and the number of parts of the pressure reducing valve 1 can be reduced.

[0042] Furthermore, in the pressure reducing valve 1 of this embodiment, the leaf spring 14 divides the accommodation space 16 into the open space 35 and the secondary chamber 36 and seals between the secondary chamber 36 and the open space 35. Therefore, since the leaf spring 14 also has a sealing function, the number of parts can be reduced, and the pressure reducing valve 1 can be made smaller.

[0043] Furthermore, in the pressure reducing valve 1 of this embodiment, the leaf spring 14 abuts against the base end surface of the stem 13. Therefore, the leaf spring 14 can be displaced relative to the stem 13. This makes it possible to prevent the stem 13 from sliding eccentrically in the casing 10. Therefore, the stem 13 can be moved smoothly.

[0044] Furthermore, in the pressure reducing valve 1 of this embodiment, the leaf spring 14 is formed in a disk shape that is convex in the opening direction, so that the stem 13 can be smoothly biased in the opening direction while keeping the height of the pressure reducing valve 1 small.

[0045] Furthermore, in the pressure reducing valve 1 of this embodiment, the leaf spring 14 includes an outer edge portion 14b and a central portion 14a. The outer edge portion 14b is flat and is attached to the casing 10. The central portion 14a is flat and abuts against the stem 13. Therefore, the leaf spring 14 can be easily attached to the casing 10 and the stem 13.

[0046] Furthermore, in the pressure reducing valve 1 of this embodiment, the leaf spring 14 has a tapered portion 14c. Therefore, when the leaf spring 14 bends, the tapered portion 14c elastically deforms while changing the relative angle between the outer edge portion 14b and the central portion 14a, and the central portion 14a can move in parallel. This allows the stem 13 to abut straight.

[0047] Furthermore, in the pressure reducing valve 1 of this embodiment, the communication passage 13c is connected to the secondary-side passage 20 via the secondary chamber 36. This makes it possible to reduce the number of passages formed in the casing 10. This makes it possible to prevent the pressure reducing valve 1 from becoming large.

[0048] [Other Embodiments] In this embodiment, the leaf spring 14 abuts against the valve disc 11, but it may also be fixed to the valve disc 11. Furthermore, the leaf spring 14 is not limited to the shape described above, and may have any plate shape (e.g., rectangular when viewed in the axial direction) extending laterally from the valve disc 11. Furthermore, the leaf spring 14 does not necessarily have a pressure-receiving function or a sealing function, and these functions may be achieved by the valve disc 11 or a separate member. That is, a pressure-receiving portion may be formed on the valve disc 11 or the stem 13, or sealing may be achieved by an O-ring or a diaphragm.

[0049] Furthermore, the secondary chamber 36 and the secondary-side passage 20 do not necessarily need to be connected, and the secondary-side passage 20 may be directly connected to the annular passage 19a. Furthermore, the secondary chamber 36 may be connected to the passage 15 via the secondary-side passage 20, or may be connected to the secondary-side passage 20 connected to the annular passage 19a via another passage or external piping. Furthermore, it is not necessary to form the communicating passage 13c in the stem 13 to guide the secondary pressure to the secondary chamber 36. For example, multiple communicating passages may be formed in the guide portion 19. Furthermore, the communicating passage may be formed inside the stem 13, or may be formed in the casing body 24.

[0050] In a first aspect, the pressure reducing valve comprises a casing including a passage, a valve body movably housed in the casing and adjusting the opening of the passage, a first biasing member urging the valve body in a closing direction, a stem movably housed in the casing and abutting against the valve body, and a second biasing member urging the valve body via the stem in an opening direction against a secondary pressure, wherein the second biasing member is a plate-shaped spring extending laterally from the stem.

[0051] According to the above aspect, the second biasing member is a plate-shaped spring extending laterally from the stem, thereby making it possible to reduce the axial dimension of the pressure reducing valve.

[0052] In a second aspect of the pressure reducing valve, in the pressure reducing valve of the first aspect, the casing includes a secondary chamber to which a secondary pressure is introduced, and the secondary chamber is formed to face the second biasing member.

[0053] According to the above aspect, the secondary chamber is formed to face the second biasing member. Therefore, the second biasing member receives the secondary pressure from the secondary chamber and moves the valve element to a position corresponding to the secondary pressure via the stem. This adjusts the opening of the passage according to the secondary pressure. Therefore, a pressure-receiving member that receives the secondary pressure can be omitted, and the number of parts of the pressure reducing valve can be reduced.

[0054] In a third aspect, in the pressure reducing valve of the second aspect, the casing includes an accommodation space that accommodates the second biasing member, and the second biasing member divides the accommodation space into an open space that is open to the atmosphere and the secondary chamber, and seals between the secondary chamber and the open space.

[0055] According to the above aspect, the second biasing member divides the accommodation space into the open space and the secondary chamber and seals between the secondary chamber and the open space. Therefore, since the second biasing member also has a sealing function, the number of parts can be reduced, and the pressure reducing valve can be made smaller.

[0056] In a fourth aspect, the pressure reducing valve is the pressure reducing valve of any one of the first to third aspects, wherein the stem is arranged to be slidably guided within the casing, and the second biasing member abuts against an end face of the stem.

[0057] According to the above aspect, the second biasing member abuts against the end surface of the stem. Therefore, the second biasing member can be displaced relative to the stem. This can prevent the stem from sliding eccentrically in the casing. Therefore, the stem can be moved smoothly.

[0058] In a fifth aspect of the pressure reducing valve, in the pressure reducing valve of any one of the first to fourth aspects, the second biasing member is formed in a disk shape that is convex in the opening direction.

[0059] According to the above aspect, the second biasing member is formed in a disk shape that is convex in the opening direction, so that the stem can be smoothly biased in the opening direction while keeping the height of the pressure reducing valve small.

[0060] In a sixth aspect, the pressure reducing valve is the pressure reducing valve of the fifth aspect, wherein the second biasing member includes an outer edge portion and a central portion, the outer edge portion of the second biasing member being flat and attached to the casing, and the central portion of the second biasing member being flat and abutting against the stem.

[0061] According to the above aspect, the second biasing member includes an outer edge portion and an intermediate portion. The outer edge portion is flat and attached to the casing. The intermediate portion is flat and abuts against the stem. Therefore, the second biasing member can be easily attached to the casing and the stem.

[0062] In a seventh aspect of the pressure reducing valve, in the sixth aspect, the second biasing member includes a tapered portion connecting the outer edge portion and the central portion.

[0063] According to the above aspect, the second biasing member has a tapered portion connecting the outer edge portion and the central portion. Therefore, when the leaf spring is bent, the tapered portion elastically deforms while changing the relative angle between the outer edge portion and the central portion, allowing the central portion to move in parallel. This allows the stem to be pushed straight.

[0064] In an eighth aspect, the pressure reducing valve is the pressure reducing valve of the second or third aspect, wherein the casing includes a guide portion that guides the stem in sliding motion and a secondary-side passage that is connected to a secondary port, and a communication passage that is connected to the secondary chamber is formed in at least one of the guide portion and the stem, and the communication passage is connected to the secondary-side passage via the secondary chamber.

[0065] According to the above aspect, the communication passage is connected to the secondary-side passage via the secondary chamber, which makes it possible to reduce the number of passages formed in the casing, thereby preventing the pressure reducing valve from becoming large.

[0066] From the above description, many modifications and other embodiments of the present disclosure will be apparent to those skilled in the art. Therefore, the above description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present disclosure. Details of the structure and / or function thereof can be substantially changed without departing from the spirit of the present disclosure.

[0067] REFERENCE SIGNS LIST 1 pressure reducing valve 10 casing 11 valve body 12 coil spring (first biasing member) 13 stem 13c communication passage 14 leaf spring (second biasing member) 14a central portion 14b outer edge portion 14c tapered portion 15 passage 16 accommodation space 19 guide portion 20 secondary side passage 35 open space 36 secondary chamber

Claims

1. A pressure reducing valve comprising: a casing including a passage; a valve body movably housed in the casing and adjusting the opening degree of the passage; a first biasing member urging the valve body in a closing direction; a stem movably housed in the casing and abutting the valve body; and a second biasing member urging the valve body via the stem in an opening direction against a secondary pressure, wherein the second biasing member is a plate-shaped spring extending laterally from the stem.

2. A pressure reducing valve as set forth in claim 1, wherein said casing includes a secondary chamber to which a secondary pressure is introduced, said secondary chamber being formed to face said second biasing member.

3. A pressure reducing valve as described in claim 2, wherein the casing includes an accommodation space that accommodates the second biasing member, and the second biasing member divides the accommodation space into an open space open to the atmosphere and the secondary chamber, and seals between the secondary chamber and the open space.

4. The pressure reducing valve according to claim 1, wherein the stem is arranged so as to be slidably guided within the casing, and the second biasing member abuts against an end face of the stem.

5. The pressure reducing valve according to claim 1, wherein the second biasing member is formed in a disk shape that is convex in the opening direction.

6. The pressure reducing valve as described in claim 5, wherein the second urging member includes an outer edge portion and a central portion, the outer edge portion of the second urging member is flat and attached to the casing, and the central portion of the second urging member is flat and abuts against the stem.

7. The pressure reducing valve according to claim 6, wherein said second biasing member includes a tapered portion connecting said outer edge portion and said central portion.

8. A pressure reducing valve as described in claim 2, wherein the casing includes a guide portion that slides and guides the stem, and a secondary side passage connected to a secondary port, and at least one of the guide portion and the stem has a communication passage connected to the secondary chamber, and the communication passage is connected to the secondary side passage via the secondary chamber.

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