Pressure reducing valve and its manufacturing method

Abstract

To provide a pressure reducing valve which enables easy dimensional control and is made of a synthetic resin, and to provide a manufacture method of the pressure reducing valve.SOLUTION: A pressure reducing valve 1 according to the present invention comprises: a housing 2 having an inlet 2a and an outlet 2b and allowing a fluid flowing in through the inlet 2a to pass through the inside and flow out through the outlet 2b; a valve body 3 movably housed in the housing 2; a valve seat 4 installed in the housing 2; and a biasing member 5 that biases the valve body 3 in a direction away from the valve seat 4. The pressure reducing valve is configured such that an increase in pressure of the fluid at the outlet causes the valve body 3 to abut against the valve seat 4 countering a biasing force of the biasing member 5, thereby enabling cutting-off of flowing of the fluid in the housing 2. The housing 2 includes a housing body 21 and a cap 22, and the cap 22 is welded to a synthetic resin member (a valve seat frame body 41).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pressure reducing valve and a method for manufacturing the same. [Background technology]

[0002] Conventionally, pressure reducing valves have been known that are installed in a flow path leading to a water discharge device such as a shower, and that narrow the opening to reduce the downstream pressure when the downstream pressure increases, thereby adjusting the downstream pressure to an appropriate pressure (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-320723 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, a pressure reducing valve includes a housing, which includes a cylindrical housing body and a cap that prevents components from falling out of the housing body. The dimensions of individual pressure reducing valves vary due to variations in the dimensions of the components that are fixed between the housing body and the cap, resulting in differences in the dimensions of each individual pressure reducing valve. To prevent this, conventional pressure reducing valves adjust the dimensions of the pressure reducing valve by compressing a portion of a metal valve seat frame that forms part of the valve seat.

[0005] However, when the pressure reducing valve is manufactured from synthetic resin, it is not possible to crush a portion of the valve seat frame, making it difficult to control the dimensions of the pressure reducing valve.

[0006] In view of the above, an object of the present invention is to provide a pressure reducing valve made of synthetic resin that is easy to control in size, and a method for manufacturing the same. [Means for solving the problem]

[0007] [1] In order to achieve the above object, the pressure reducing valve of the present invention (for example, pressure reducing valve 1 of the embodiment; the same applies hereinafter) a housing made of synthetic resin (for example, housing 2 in the embodiment; the same applies hereinafter) having an inlet and an outlet, through which a fluid flowing in from the inlet can pass and flow out from the outlet; A valve body (for example, valve body 3 in the embodiment; the same applies hereinafter) movably accommodated in the housing; A valve seat (for example, valve seat 4 in the embodiment; the same applies hereinafter) provided in the housing; A biasing member (for example, biasing member 5 in the embodiment; the same applies hereinafter) that biases the valve body in a direction away from the valve seat; Equipped with a pressure reducing valve capable of blocking the flow of fluid in the housing by causing the valve body to come into contact with the valve seat against the biasing force of the biasing member when pressure of the fluid at the outlet increases, The housing includes a housing body (for example, the housing body 21 in the embodiment; the same applies hereinafter) and a cap (for example, the cap 22 in the embodiment; the same applies hereinafter), a synthetic resin member (for example, a valve seat frame 41 in the embodiment; the same applies hereinafter) is disposed so as to be sandwiched between the housing body and the cap; The cap is welded to the synthetic resin member. R, the cap or the synthetic resin member has a dimension adjusting protrusion, The cap is welded to the synthetic resin member by melting the dimension adjusting projection. It is characterized by being

[0008] [ 4 ] Also, the manufacturing method of the pressure reducing valve of the present invention includes: a housing having an inlet and an outlet, through which fluid flowing in from the inlet can pass through the inside and flow out from the outlet; a valve body movably accommodated within the housing; a valve seat disposed within the housing; a biasing member that biases the valve body in a direction away from the valve seat; Equipped with A method for manufacturing a pressure reducing valve capable of blocking the flow of fluid in the housing by causing the valve body to abut against the valve seat against the biasing force of the biasing member when pressure of the fluid at the outlet increases, comprising: The housing includes a housing body and a cap. a synthetic resin member is disposed between the housing body and the cap; The contact portion between the cap and the synthetic resin member is melted by applying ultrasonic vibration. height, the cap or the synthetic resin member has a dimension adjusting protrusion at the contact portion, The cap is vibrated with ultrasonic waves to melt the dimension adjusting projections. It is characterized by the following.

[0009] According to the present invention, the dimensions of the pressure reducing valve can be adjusted by adjusting the amount of welding between the cap and the synthetic resin member or the amount of melting at the contact portion between the cap and the synthetic resin member. Therefore, even with a pressure reducing valve made of synthetic resin, the dimensions can be adjusted without crushing part of the valve seat as in a metal pressure reducing valve, and the dimensions of the pressure reducing valve can be easily controlled.

[0010] [2][ 5 In addition, in the pressure reducing valve or the manufacturing method thereof of the present invention, The valve seat includes a seat member (e.g., an O-ring 42 in the embodiment; the same applies hereinafter) that can come into contact with the valve body, and a valve seat frame (e.g., a valve seat frame 41 in the embodiment; the same applies hereinafter) that holds the seat member, The valve seat frame may be the synthetic resin member.

[0011] According to this configuration, the valve seat frame that constitutes the valve seat can be used as a synthetic resin member for dimensional adjustment, so that an increase in the number of parts of the pressure reducing valve can be suppressed.

[0012] Also, In the pressure reducing valve of the present invention, the cap or the synthetic resin member has a dimension adjusting protrusion, The size-adjusting protrusion is melted to weld the cap and the synthetic resin member together. will be done.

[0013] Also, In the method for manufacturing a pressure reducing valve of the present invention, the cap or the synthetic resin member has a dimension adjusting protrusion at the abutting portion, The cap is vibrated with ultrasonic waves to melt the dimension adjusting protrusions. do.

[0014] According to this configuration, the size of the pressure reducing valve can be adjusted by melting the size adjusting protrusion. The size adjusting protrusion has a convex shape, and this shape allows the size adjusting protrusion to be melted more actively than the contact portion of the mating part, making it easy to adjust the size of the pressure reducing valve.

[0015] [ 3][6 ]Furthermore, in the pressure reducing valve or the manufacturing method thereof of the present invention, either the cap on which the dimension adjustment protrusion is formed or the synthetic resin member may be formed from a material that melts more easily than the other.

[0016] According to this configuration, the dimension adjusting projection can be melted more actively, so that the dimension of the pressure reducing valve can be adjusted more easily.

[0017] [ 7 In addition, in the method for manufacturing a pressure reducing valve of the present invention, after ultrasonic welding of the housing body and the cap is started, melting of the contact portion between the cap and the synthetic resin member may be started.

[0018] According to this configuration, a welding margin between the housing body and the cap can be ensured, which makes it easier to ensure the joining strength between the housing body and the cap. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 2 is an explanatory diagram showing an open state of the pressure reducing valve according to the first embodiment of the present invention. [Figure 2] FIG. 2 is an explanatory diagram showing a closed state of the pressure reducing valve according to the first embodiment of the present invention. [Figure 3] 1 is a perspective view showing a cap of a pressure reducing valve according to a first embodiment of the present invention. [Figure 4] 1 is a perspective view showing a housing main body of a pressure reducing valve according to a first embodiment of the present invention. [Figure 5] 1 is an explanatory view showing a state before welding between a cap and a housing body of a pressure reducing valve according to a first embodiment of the present invention is started. FIG. [Figure 6] FIG. 3 is an explanatory view showing a state at the start of welding between the cap and the housing body of the pressure reducing valve according to the first embodiment of the present invention. [Figure 7] FIG. 3 is an explanatory view showing a state at the start of welding between the cap and the valve seat frame of the pressure reducing valve according to the first embodiment of the present invention. [Figure 8] FIG. 4 is an explanatory view showing a state in which the melting amount of the dimension adjusting protrusion of the pressure reducing valve according to the first embodiment of the present invention is small. [Figure 9] FIG. 4 is an explanatory view showing a state in which the dimension-adjusting protrusion of the pressure reducing valve according to the first embodiment of the present invention has a large amount of melting. [Figure 10] FIG. 4 is an explanatory diagram showing a modified example of the pressure reducing valve according to the first embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] 1 to 9, a pressure reducing valve 1 according to a first embodiment of the present invention will be described. With reference to Fig. 1 and Fig. 2, the pressure reducing valve 1 of the first embodiment comprises a cylindrical housing 2 made of synthetic resin and having an inlet 2a and an outlet 2b, a cylindrical valve element 3 made of synthetic resin arranged within the housing 2 to be slidable in the central axis direction, a valve seat 4 with which the valve element 3 comes into contact and separates, a biasing member 5 (e.g., a coil spring) that biases the valve element 3 in a direction separating it from the valve seat 4, a spring seat 6 that supports one end of the biasing member 5, and a holder 7 that is stacked on the spring seat 6. Hereinafter, for convenience of explanation, the top and bottom of the pressure reducing valve 1 in Figs. 1 and 2 will be simply referred to as "top" and "bottom".

[0021] The housing 2 comprises a cylindrical housing main body 21 that is open at the top and has a through-hole 21a at the bottom 21e that serves as the inlet 2b, and a cap 22 that is attached to the opening at the top of the housing main body 21 and that, together with the housing main body 21, fixes the valve seat 4, spring seat 6, and holder 7 inside the housing 2. The cap 22 has an opening that serves as the inlet 2a, and fluid can flow into the housing 2 through this inlet 2a. A female thread is provided on the inner circumferential surface of the inlet 2a where the opening of the cap 22 is provided.

[0022] The inner peripheral surface of the housing body 21 is formed, from the bottom 21e side, with a small diameter portion 21b and a large diameter portion 21c that is larger in diameter than the small diameter portion 21b. An annular step 21d is formed at the boundary between the small diameter portion 21b and the large diameter portion 21c. A male thread is formed on the outer peripheral surface of the housing body 21 on the bottom 21e side. The outer diameter of the male thread portion 21g on which the male thread is formed is smaller than the outer diameter of the rest of the housing body 21, and an annular outer peripheral step 21h is formed between the male thread portion 21b and the rest of the outer peripheral surface of the housing body 21. In the pressure reducing valve 1, the dimension x from the outer peripheral step 21h to the upper end of the cap 22 is adjusted to be a predetermined arbitrary dimension (predetermined dimension).

[0023] The cap 22 is ultrasonically welded to the housing body 21. Referring to Fig. 3, ribs 22a that protrude radially outward are arranged at intervals in the circumferential direction on the outer peripheral surface of the cap 22. Each rib 22a extends in the direction in which the cap 22 is inserted into the housing body 21. Referring to Fig. 4, the large diameter portion 21c of the housing body 21 is provided with a plurality of grooves 21f that allow the ribs 22a to pass through.

[0024] 1 and 2, the step portion 21d is provided with an annular spring seat 6, which abuts against the upper end (one end) of the biasing member 5, an annular holder 7, and a valve seat 4, stacked in this order from the step portion 21d side. The spring seat 6, the holder 7, and the valve seat 4 are then sandwiched and fixed between the step portion 21d and the cap 22. A cylindrical portion 31 (described later) of the valve body 3 is inserted into the center of the spring seat 6 and the holder 7 so as to be movable in the axial direction. Elastic annular sealing members 6a and 6b are provided on the inner and outer peripheries of the spring seat 6. The inner sealing member 6a provides a liquid-tight seal between the spring seat 6 and the cylindrical portion 31 of the valve body 3. The outer sealing member 6b provides a liquid-tight seal between the spring seat 6 and the housing 2. The holder 7 presses the sealing members 6a and 6b from above.

[0025] The valve body 3 includes a cylindrical portion 31 having a circular cross section, a protruding portion 32 that protrudes radially outward from the center of the cylindrical portion 31, and an annular elastic sealing member 32a that is fitted into a fitting groove provided on the outer periphery of the protruding portion 32 and liquid-tightly seals the gap between the small diameter portion 21b of the housing 2 and the protruding portion 32. The cylindrical portion 31 of the valve body 3 is inserted through the center of the spring seat 6 and the holder 7, and the upper end (tip) of the cylindrical portion 31 faces an O-ring 42 of the valve seat 4, which will be described later.

[0026] The valve seat 4 includes a synthetic resin valve seat frame 41, an O-ring 42 as a seat member, and a synthetic resin lid member 43. The valve seat frame 41 includes an annular outer ring portion 41a, an inner ring portion 41b disposed inside the outer ring portion 41a with a gap therebetween, and a bridge portion 41c connecting the outer ring portion 41a and the inner ring portion 41b with a gap therebetween. The outer periphery of the outer ring portion 41a is pressed from above by the cap 22.

[0027] The cover member 43 includes a closure plate 43a that closes the upper edge of the inner annular portion 41b, an inner circumferential portion 43b that hangs down from the center of the closure plate 43a and passes through a hole in the center of the O-ring 42, and a first anti-detachment portion 43c that is provided at the lower end of the inner circumferential portion 43b and has a larger diameter than the inner circumferential portion 43b to prevent the O-ring 42 from falling off the inner annular portion 41b. The closure plate 43a is ultrasonically welded to the upper edge of the inner annular portion 41b. A second anti-detachment portion (not shown) that protrudes inward is provided at the lower end of the inner annular portion 41b, and the O-ring 42 is held in the valve seat frame 41 by the first anti-detachment member 43c and the second anti-detachment portion, with the contact portion with the valve disc 3 exposed.

[0028] Next, the operation of the pressure reducing valve 1 of this embodiment will be described. In the pressure reducing valve 1 of this embodiment, a fluid (e.g., cold water or hot water) passes through the pressure reducing valve 1 from top to bottom as shown by the dashed-dotted line in FIG. 1 . The valve element 3 is subjected to an upward force due to the pressure on the outlet 2b side. When the pressure on the outlet 2b side increases, the valve element 3 moves upward against the biasing force of the biasing member 5, narrowing the gap between the valve element 3 and the valve seat 4 and increasing the pressure loss when the fluid passes through the gap. This reduces the pressure on the outlet 2b side, and the flow rate of the fluid passing through the pressure reducing valve 1 decreases. The valve element 3 comes to rest at a position where the upward force due to the pressure on the outlet 2b side and the downward force of the biasing member 5 are balanced. When the pressure on the outlet 2b side exceeds a predetermined value, the upper edge of the valve element 3 abuts against the O-ring 42, as shown in FIG. 2 , and the flow of the fluid through the pressure reducing valve 1 is blocked.

[0029] Next, a method for manufacturing the pressure reducing valve 1 of the first embodiment will be described.

[0030] The pressure reducing valve 1 has a first welded portion 10 which is a welded portion between the cap 22 and the housing main body 21, and a second welded portion 11 which is a welded portion between the cap 22 and the valve seat frame 41. The first welded portion 10 and the second welded portion 11 are joined by ultrasonic welding. In the first embodiment, the cap 22 and the housing main body 21 are made of a POM (polyacetal) resin. The valve seat frame 41 is made of a PPS (polyphenylene sulfide) resin, and the cap 22 is made of a material which is more easily melted than the valve seat frame 41.

[0031] First weld portion 10 is located on the inner periphery of the upper end of housing main body 21. Referring to Fig. 5, before welding, a tapered surface 9 that gradually increases in diameter toward the top is formed on the inner periphery of the upper end of housing main body 21, which becomes first weld portion 10. Furthermore, before welding, an annular corner 22b is formed on the outer periphery of cap 22, which becomes first weld portion 10. This corner 22b abuts against tapered surface 9 from above.

[0032] The second welded portion 11 is located at the upper end of the outer periphery of the outer annular portion 41a of the valve seat frame 41. Referring to FIG. 5, before welding, an upward-facing annular flat surface 41g is formed on the outer periphery of the outer annular portion 41a. Furthermore, before welding, the cap 22 that becomes the second welded portion 11 is provided with an annular dimension-adjusting protrusion 8 that protrudes downward. The tip of this dimension-adjusting protrusion 8 abuts against the flat surface 41g from above. This dimension-adjusting protrusion 8 is a portion that is melted to adjust the dimension x of the pressure reducing valve 1 to a predetermined dimension, and in some cases it may be melted completely and disappear.

[0033] In this way, the corner 22b of the cap 22 and the dimension adjusting projection 8 abut against the tapered surface 9 and the flat surface 41g from above. These abutting portions can be simultaneously pressed when a downward force is applied to the cap 22.

[0034] At the start of the pre-welding process of the pressure reducing valve 1, the valve disc 3, biasing member 5, spring seat 6, holder 7, and valve seat 4 are inserted into the upper end opening of the housing main body 21, and then the cap 22 is placed on top of them, as shown in Figure 5. In this state, the biasing member 5 pushes up the spring seat 6, holder 7, and valve seat 4, and the dimension adjusting projection 8 of the cap 21 comes into contact with the flat surface 41g of the valve seat frame body 41.

[0035] In the pre-welding step, a downward force is applied to the cap 22, compressing the biasing member 5 and pushing the cap 22 downward into the housing main body 21. As the welding preparation step progresses, as shown in Figure 6, the corner portion 22b of the cap 22 abuts against the tapered surface 9, and the process moves to the first welding step.

[0036] In the first welding step, a downward force is applied to cap 22 while ultrasonically vibrating cap 22. This applies pressure to the contact portion between corner portion 22b of cap 22 and tapered surface 9 of housing main body 21, causing them to melt due to frictional heat. As a result, cap 22 is ultrasonically welded to housing main body 21, and first weld portion 10 is formed.

[0037] In this first welding step, the spring seat 6 is separated from the stepped portion 21d. Therefore, although the dimension-adjusting projection 8 of the cap 22 and the flat surface 41g of the valve seat frame 41 are in contact with each other, the pressure applied to the contacting portion is caused by the biasing member 5 and is not high enough to initiate welding. Therefore, in the first welding step, the cap 22 is not welded to the valve seat frame 41, but is welded only to the housing main body 21. As the first welding step proceeds, the spring seat 6 abuts against the stepped portion 21d, as shown in Figure 7, and the process moves to the second welding step.

[0038] In the second welding step, continuing from the first welding step, a downward force is applied to the cap 22 while ultrasonically vibrating the cap 22. As a result, the welding of the first weld portion 10 progresses, and the contact portion between the dimension-adjusting projection 8 of the cap 22 and the flat surface 41g of the valve seat frame 41 is pressurized and melted by frictional heat. As a result, the cap 22 is ultrasonically welded to the valve seat frame 41, and the second weld portion 11 is formed.

[0039] In this second welding step, welding of cap 22 to housing body 21 at first welded portion 10 and welding of cap 22 to valve seat frame 41 at second welded portion 11 proceed simultaneously. When dimension x of pressure reducing valve 1 reaches a predetermined dimension as the second welding step proceeds, vibration of cap 22 is stopped. This ends the welding step and pressure reducing valve 1 is completed.

[0040] In the pressure reducing valve 1 having a predetermined dimension, when the dimension y of the parts (spring seat 6, holder 7, and valve seat frame 41) housed in the housing 2 and sandwiched between the cap 22 and the step portion 21d is small, the melting amount of the dimension adjusting protrusion 8 is small, as shown in Fig. 8. On the other hand, when the dimension y of the parts housed in the housing 2 and sandwiched between the cap 22 and the step portion 21d is large, the melting amount of the dimension adjusting protrusion 8 is large, as shown in Fig. 9.

[0041] As described above, the pressure reducing valve 1 of the first embodiment comprises the housing 2 made of synthetic resin, which has an inlet 2a and an outlet 2b and through which fluid flowing in from the inlet 2a can pass and flow out from the outlet 2b, the valve element 3 movably accommodated within the housing 2, the valve seat 4 provided within the housing 2, and the biasing member 5 which biases the valve element 3 in a direction away from the valve seat 4. When the pressure of the fluid at the outlet 2b increases, the pressure reducing valve 1 causes the valve element 3 to come into contact with the valve seat 4 against the biasing force of the biasing member 5, thereby blocking the flow of fluid within the housing 2.

[0042] The housing 2 includes a housing body 21 and a cap 22. A valve seat frame 41 (a synthetic resin member) is disposed so as to be sandwiched between the housing body 21 and the cap. According to the pressure reducing valve 1 of the first embodiment, the cap 22 is welded to the valve seat frame 41. Furthermore, according to the manufacturing method of the pressure reducing valve 1 of the first embodiment, the contact portion between the cap 22 and the valve seat frame 41 is ultrasonically vibrated and melted.

[0043] This makes it possible to adjust the dimension x of the pressure reducing valve 1 by adjusting the amount of welding between the cap 22 and the valve seat frame 41 or the amount of melting at the contact portion between the cap 22 and the valve seat frame 41. Therefore, even in the case of a pressure reducing valve made of synthetic resin, the dimension can be adjusted without crushing part of the valve seat as in the case of a metal pressure reducing valve, and the dimension control of the pressure reducing valve 1 can be made easier.

[0044] In the first embodiment, the dimension x from the outer peripheral step 21h of the pressure reducing valve 1 to the upper end of the cap 22 is adjusted to a predetermined dimension, but the dimension adjustment of the pressure reducing valve of the present invention is not limited to this. For example, the dimension of the pressure reducing valve adjusted by the present invention may be the overall length of the pressure reducing valve, or any dimension in the up-down direction (axial direction) of the pressure reducing valve. Furthermore, for the dimension adjustment, it is sufficient that at least one of the cap 22 or the valve seat frame 41 is melted, and the cap 22 and the valve seat frame 41 do not necessarily have to be joined together.

[0045] Furthermore, according to the pressure reducing valve 1 of the first embodiment and the manufacturing method thereof, the valve seat 4 includes an O-ring 42 (seat member) that can come into contact with the valve element 3, and a valve seat frame 41 that holds the O-ring 42. This valve seat frame 41 is a synthetic resin member. This allows the valve seat frame 41 that constitutes the valve seat 4 to be used as a synthetic resin member for adjusting dimensions, thereby preventing an increase in the number of parts of the pressure reducing valve 1.

[0046] In the first embodiment, the valve seat frame 41 is used as the synthetic resin member, but the synthetic resin member of the present invention is not limited to the valve seat frame 41. For example, the spring seat 6 or the holder 7 may be the synthetic resin member of the present invention, or a washer, a spacer, or the like may be laminated on the valve seat frame 41 to form the synthetic resin member of the present invention.

[0047] Furthermore, the cap 22 has a dimension adjusting protrusion 8. In the pressure reducing valve 1 of the first embodiment, the cap 22 is welded to the valve seat frame 41 by melting the dimension adjusting protrusion 8. Furthermore, according to the manufacturing method of the pressure reducing valve 1 of the first embodiment, the dimension adjusting protrusion 8 is melted by vibrating the cap 22 with ultrasonic waves. With this configuration, the dimension of the pressure reducing valve 1 can be adjusted by melting the dimension adjusting protrusion 8. Furthermore, the dimension adjusting protrusion 8 has a convex shape. With such a shape, the dimension adjusting protrusion 8 can be actively melted, making it possible to easily adjust the dimension of the pressure reducing valve 1.

[0048] In the first embodiment, the dimension adjusting protrusion 8 is provided on the cap 22, but the dimension adjusting protrusion of the present invention may be provided on a synthetic resin member. In the first embodiment, the dimension adjusting protrusion 8 is annular, but the dimension adjusting protrusion of the present invention is not limited to this and may be, for example, arc-shaped, or may be multiple protrusions arranged on the same circumference. Furthermore, the dimension adjusting protrusion may not be necessary as long as the cap or synthetic resin member can be melted to adjust the dimension.

[0049] Furthermore, the cap 22 on which the dimension adjusting projections 8 are formed is made of a material that melts more easily than the valve seat frame 41 (the synthetic resin member of the valve seat 4). For example, the cap 22 and the housing body 21 are made of POM (polyacetal) resin, and the valve seat frame 41 (the synthetic resin member of the valve seat 4) is made of PPS (polyphenylene sulfide) resin. This allows the dimension adjusting projections 8 to melt more actively, making it easier to adjust the dimension of the pressure reducing valve 1.

[0050] In the present invention, when the dimension adjusting projection is provided on the synthetic resin member, the same effect can be obtained by forming the synthetic resin member from a material that melts more easily than the cap.

[0051] Generally, when ultrasonic welding is performed, the materials of the parts to be welded are the same to ensure the bonding strength of the welded portion. The dimension-adjusting protrusion 8 is intended for melting to adjust the dimension and does not require bonding strength, so in the first embodiment, the cap 22 and the valve seat frame 41 are made of different materials. To ensure the bonding strength between the cap 22 and the housing main body 21, they are preferably made of the same material, but the material can be changed as appropriate. The material of the synthetic resin member of the present invention can also be changed as appropriate, and may be the same material as the housing 2.

[0052] Furthermore, according to the manufacturing method of the pressure reducing valve of the first embodiment, by configuring the spring seat 6 to be away from the step portion 21d when the corner portion 22b and the tapered surface 9 come into contact, melting of the contact portion between the cap 22 and the valve seat frame 41 (a synthetic resin member) begins after ultrasonic welding of the housing body 21 and the cap 22 has begun. This makes it possible to adjust the dimensions of the pressure reducing valve 1 by increasing or decreasing the amount of melting of the contact portion between the cap 22 and the valve seat frame 41, while ensuring a welding allowance between the housing body 21 and the cap 22. In other words, since a welding allowance between the housing body 21 and the cap 22 can be ensured, it is easy to ensure the joining strength between the housing body 21 and the cap 22.

[0053] In the first embodiment, a rib 22a extending in the direction of insertion of the cap 22 into the housing body 21 is formed on the outer periphery of the cap 22. A groove 21f that allows the rib 22a to pass through is formed on the inner periphery of the housing body 21. In this way, the rib 22a fits into the groove 21f, preventing the cap 22 from rotating around the housing body 21, thereby improving the bonding strength between the cap 22 and the housing body 21.

[0054] Furthermore, in the first embodiment, the ribs 22a are provided so as to be continuous with the corners 22b. Therefore, when the corners 22b are melted, the molten synthetic resin enters the gaps between the ribs 22a and the grooves 21f, filling the gaps, thereby further improving the bonding strength between the cap 22 and the housing body 21. The number, thickness, and length of the ribs 22a and the grooves 21f can be changed as appropriate. Furthermore, the ribs 22a and the grooves 21f may be omitted.

[0055] In the first embodiment, the lower end of the inner circumferential portion 43a is located at the same level as or higher than the lower end of the inner annular portion 41b. This prevents excessive water flow resistance, which can lead to negative pressure and abnormal noise when the tip of the tubular portion 31 of the valve body 3 approaches the O-ring. As shown in the modified example of FIG. 10, the lower end of the inner circumferential portion 43a may protrude downward from the lower end of the inner annular portion 41b. All other configurations of the pressure reducing valve 1 of this modified example are the same as those of the first embodiment, and the same functions and effects are achieved.

[0056] Although the pressure reducing valve and the manufacturing method thereof according to the first and second embodiments have been described above, the present invention can be appropriately modified and changed without departing from the scope of the claims. [Explanation of symbols]

[0057] 1 Pressure reducing valve 2. Housing 2a Inlet 2b Outlet 21 Housing body 21a Through hole 21b Small diameter section 21c Large diameter section 21d Stepped section 21e bottom 21f Groove 21g male thread part 21h Outer step 22 Cap 22a Rib 22b Corner 3 Valve body 31 Cylindrical part 32 Overhang 32a Sealing member 4 Valve seat 41 Valve seat frame (synthetic resin member of the first embodiment) 41a Outer ring 41b Inner ring 41c bridge 41f 2nd fall prevention part 41g plane 42 O-ring 43 Lid member 43a Closure plate part 43b Inner circumference 43c 1st fall prevention part 5. Pressurizing member 6 Spring seat (synthetic resin member in other embodiments) 6a Sealing member 6b Sealing member 7 Holder (synthetic resin member in other embodiments) 8 Dimension adjustment protrusion 9 Tapered surface 10 First weld part 11 Second weld part x dimension y dimension

Claims

1. a housing made of synthetic resin having an inlet and an outlet, through which fluid flowing in from the inlet can pass through the inside and flow out from the outlet; a valve body movably accommodated within the housing; a valve seat disposed within the housing; a biasing member that biases the valve body in a direction away from the valve seat; Equipped with a pressure reducing valve capable of blocking the flow of fluid in the housing by causing the valve body to come into contact with the valve seat against the biasing force of the biasing member when pressure of the fluid at the outlet increases, The housing includes a housing body and a cap. a synthetic resin member is disposed between the housing body and the cap; The cap is welded to the synthetic resin member, the cap or the synthetic resin member has a dimension adjusting protrusion, The pressure reducing valve is characterized in that the cap is welded to the synthetic resin member by melting the dimension adjusting projection.

2. 2. The pressure reducing valve according to claim 1, the valve seat includes a seat member that can come into contact with the valve body, and a valve seat frame that holds the seat member, A pressure reducing valve, wherein the valve seat frame is made of the synthetic resin material.

3. The pressure reducing valve according to claim 1 or 2, A pressure reducing valve, wherein either the cap on which the dimension adjusting projection is formed or the synthetic resin member is made of a material that melts more easily than the other.

4. a housing having an inlet and an outlet, through which fluid flowing in from the inlet can pass through the inside and flow out from the outlet; a valve body movably accommodated within the housing; a valve seat disposed within the housing; a biasing member that biases the valve body in a direction away from the valve seat; Equipped with A method for manufacturing a pressure reducing valve capable of blocking the flow of fluid in the housing by causing the valve body to abut against the valve seat against the biasing force of the biasing member when pressure of the fluid at the outlet increases, comprising: The housing includes a housing body and a cap. a synthetic resin member is disposed between the housing body and the cap; The contact portion between the cap and the synthetic resin member is ultrasonically vibrated to melt the contact portion, the cap or the synthetic resin member has a dimension adjusting protrusion at the contact portion, A method for manufacturing a pressure reducing valve, characterized in that the dimension adjusting projection is melted by applying ultrasonic vibration to the cap.

5. A method for manufacturing the pressure reducing valve according to claim 4, the valve seat includes a seat member that can come into contact with the valve body, and a valve seat frame that holds the seat member, The method for manufacturing a pressure reducing valve, wherein the valve seat frame is the synthetic resin member.

6. A method for manufacturing a pressure reducing valve according to claim 4 or 5, comprising the steps of: A method for manufacturing a pressure reducing valve, wherein either the cap or the synthetic resin member on which the dimension adjusting projection is formed is made of a material that melts more easily than the other.

7. A method for manufacturing a pressure reducing valve according to any one of claims 4 to 6, a first ultrasonic welding step for welding the housing body and the cap together, the first ultrasonic welding step being performed on the housing body and the cap; a second ultrasonic welding step for welding the housing body and the cap together;

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