Fluid control valve

Abstract

To provide a fluid control valve capable of preventing the occurrence of partial contact of a valve element with an annular valve seat.SOLUTION: A fluid control valve 1 comprises a metal annular valve seat 317, a resin valve element 34 that abuts against and separates from the annular valve seat 317, a drive rod 24 that extends along a direction of abutment and separation on the side opposite the annular valve seat 317 of the valve element 34 and holds the valve element 34, and a drive unit 2 for driving the drive rod 24 along the direction of the abutment and separation to perform the abutment and separation. In the fluid control valve, the valve element 34 has an end face opposite to an abutment surface 341 that abuts against the annular valve seat 317, the end face being a convex spherical surface 342 bulging to the side of the drive rod 24. The drive rod 24 has a concave spherical surface 333 that faces the convex spherical surface 342, is engageable with the convex spherical surface 342, and has a center C11 on the axis of the drive rod 24, and the drive rod holds the valve element 34 with play in the direction of the abutment and separation and in a direction perpendicular to the direction of the abutment and separation.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a fluid control valve.

Background Art

[0002] Conventionally, high-pressure air (5 MPa or more) has been used for antilock brake systems for automobiles and airtightness inspections of hydraulic equipment. In order to control this high-pressure air, a fluid control valve provided on the supply pipeline of the high-pressure air is used. As the fluid control valve, for example, a cylinder valve 50 shown in FIG. 4 and a cylinder valve disclosed in Patent Document 1 are known.

[0003] The cylinder valve 50 shown in FIG. 4 is configured such that a drive unit 51 and a valve unit 52 are stacked along the direction (vertical direction) in which the contact and separation between a valve body 65 and an annular valve seat 64, which will be described later, occur.

[0004] The drive unit 51 is an air cylinder that operates by receiving the supply of operating air, and a piston 53 is loaded in the internal space. The piston 53 partitions the internal space into a first chamber 54 on the separation direction side and a second chamber 55 on the contact direction side. A compression coil spring 57 that biases the piston 53 in the contact direction is housed in the first chamber 54. Operating air can be supplied to the second chamber 55 from a supply port 58 through a ventilation path 59 provided in a drive rod 56, which will be described later. When the pressure in the second chamber 55 increases due to the supply of operating air, the piston 53 is slid in the separation direction against the biasing force of the compression coil spring 57.

[0005] A drive rod 56 that extends toward the valve unit 52 side is connected to the piston. Therefore, the drive rod 56 is driven in the contact and separation direction as the piston 53 slides in the contact and separation direction. The drive of the drive rod 56 in the contact and separation direction is guided by a slide bearing 60.

[0006] The valve section 52 includes an input port 61 for supplying control fluid to the cylinder valve 50, an output port 62 for supplying control fluid from the cylinder valve 50, and a valve chamber 63 connecting the input port 61 and the output port 62. An annular valve seat 64 is provided on the bottom surface of the valve chamber.

[0007] A valve body 65 is housed within the valve chamber 63, which contacts and separates from the annular valve seat 64. The valve body 65 is made of resin (e.g., polyimide) and is fixed to the valve end 52 side of the drive rod 56. The valve body 65 has a tapered shape, and the surface that contacts the annular valve seat 64 is inclined. The drive unit 51 drives the drive rod 56 along the direction of contact and separation, causing the valve body 65 and the annular valve seat 64 to contact and separate, thereby controlling the fluid flow. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 9-144903 [Overview of the project] [Problems that the invention aims to solve]

[0009] When the drive rod 56 is driven in the direction of contact and separation, it is desirable that the axis of the drive rod 56 be parallel to the direction of contact and separation. However, due to manufacturing errors or pressure exerted on the valve body 65 by the control fluid flowing into the valve chamber 63, the axis of the drive rod 56 may wobble, causing the drive rod 56 to tilt with respect to the direction of contact and separation.

[0010] If the drive rod 56 is tilted as described above when driven in the contact direction, the valve body 65 may not contact the entire circumference of the annular valve seat 64, but only a portion of it (this state where only a portion of the valve body contacts the annular valve seat is called partial contact). When partial contact occurs, even when the valve is closed, fluid input from the input port 61 will leak into the valve chamber 63 (internal leakage). Also, because the valve body 65 has a tapered shape, when the valve body 65 contacts the annular valve seat 64, it is more likely to be line contact rather than surface contact. In line contact, the load is concentrated when the valve body 65 contacts the annular valve seat 64, making the valve body 65 prone to plastic deformation. When the valve body 65 is plastically deformed, the contact area between the valve body 65 and the annular valve seat 64 changes, which may lead to unstable sealing performance when the valve is closed. Therefore, it is conceivable to use a valve body with a contact surface perpendicular to the contact-to-separation direction, such as the fluid control valve disclosed in Patent Document 1, to make surface contact with the annular valve seat. However, simply making surface contact is insufficient to prevent internal leakage when one-sided contact occurs. In order to bring the entire circumference of the annular valve seat into contact with the valve body from the one-sided contact state, a stronger force must be applied to press the valve body against the annular valve seat. This is undesirable because it increases the load on the drive unit.

[0011] The present invention has been made in view of the above problems, and aims to provide a fluid control valve capable of preventing uneven contact of the valve body with respect to the annular valve seat. [Means for solving the problem]

[0012] To solve the above problems, a fluid control valve in one aspect of the present invention has the following configuration.

[0013] (1) A fluid control valve comprising a metal annular valve seat, a resin valve body that contacts and separates with respect to the annular valve seat, a drive rod that extends along the direction of contact and separation on the side of the valve body opposite to the annular valve seat and holds the valve body, and a drive unit that drives the drive rod along the direction of contact and separation to perform the contact and separation, wherein the valve body has a convex spherical surface on the side of the end face opposite the contact surface that contacts the annular valve seat that bulges toward the drive rod, the drive rod has a concave spherical surface opposite to the convex spherical surface that is fittable with the convex spherical surface and has its center on the axis of the drive rod, and the valve body is held with play in the direction of contact and separation and in a direction perpendicular to the direction of contact and separation.

[0014] The fluid control valve described in (1) is characterized in that the valve body has a convex spherical surface on the end face opposite to the contact surface that abuts the annular valve seat, which bulges toward the drive rod, the drive rod has a concave spherical surface opposite to the convex spherical surface that is fittable with the convex spherical surface and has its center on the axis of the drive rod, and the valve body is held with play in the direction between contact and separation and in a direction perpendicular to the direction between contact and separation. As a result, the convex spherical surface of the valve body can slide along the concave spherical surface when it is in contact with the concave spherical surface of the drive rod. In other words, the valve body can be tilted with respect to the axis of the drive rod.

[0015] When the drive unit drives the drive rod to bring the valve body into contact with the annular valve seat, if the axis of the drive rod wobbles and the drive rod tilts with respect to the contact-to-separation direction, the valve body will first come into contact with a portion of the annular valve seat's circumference. If the drive force of the drive unit is then applied to the valve body, as described above, the convex spherical surface slides along the concave spherical surface, causing the valve body to tilt with respect to the axis of the drive rod. This tilt of the valve body absorbs the tilt of the drive rod, thus preventing uneven contact of the valve body with the annular valve seat. Furthermore, because uneven contact is prevented by the tilt of the valve body, there is no need to press the valve body against the annular valve seat with strong force to prevent internal leakage, and the load on the drive unit can be kept low.

[0016] In order for the convex spherical surface to slide smoothly along the concave spherical surface, it is preferable that, in the fluid control valve described in (2)(1), the convex spherical surface and the concave spherical surface have substantially the same radius.

[0017] (3) In the fluid control valve described in (1) or (2), it is preferable that the center of the convex spherical surface is located on the contact surface.

[0018] The sliding of the convex spherical surface is achieved by the valve body contacting the annular valve seat and receiving a force. In order to slide efficiently with less force, it is desirable that the position of the center of the sliding of the convex spherical surface in the direction between contact and separation be as close as possible to the annular valve seat that applies force to the valve body. According to the fluid control valve described in (3), since the center of the convex spherical surface is located on the contact surface, the position of the center of the sliding of the convex spherical surface in the direction between contact and separation is close to the annular valve seat. Therefore, it is possible to slide the convex spherical surface efficiently with less force.

[0019] (4) In the fluid control valve described in any one of (1) to (3), it is preferable that the contact surface is a plane perpendicular to the direction between the contact and separation, and that the second contact surface of the annular valve seat that contacts the contact surface is a plane parallel to the contact surface.

[0020] If the valve body and the annular valve seat repeatedly come into contact by line contact, the valve body may undergo plastic deformation, potentially reducing the sealing performance when the valve is closed. According to the fluid control valve described in (4), when the valve body and the annular valve seat come into contact, they make surface-to-surface contact, thus preventing plastic deformation of the valve body due to line contact and maintaining stable sealing performance when the valve is closed.

[0021] (5) In the fluid control valve described in any one of (1) to (4), it is preferable that the convex spherical surface and the concave spherical surface face each other over a wider area than the diameter of the second contact surface that contacts the contact surface of the annular valve seat.

[0022] If the convex spherical surface and the concave spherical surface face each other within a range narrower than the diameter of the second contact surface, that is, if they face each other on the inner peripheral side of the second contact surface, when the valve body receives a force from the annular valve seat, the sliding of the convex spherical surface will not be smooth. According to the fluid control valve described in (5), since the convex spherical surface and the concave spherical surface face each other in a range wider than the diameter of the second contact surface that contacts the contact surface of the annular valve seat, the sliding of the convex spherical surface is smooth.

[0023] (6) In the fluid control valve according to any one of (1) to (5) above, it is preferable that the drive rod is divided into a first rod extending from the drive part and a second rod on the side of the valve body in the direction of contact separation, and the end of the second rod on the side of the first rod is a free end not connected to the first rod.

[0024] In a fluid control valve (cylinder valve 50) according to the prior art, there was a possibility of single-sided contact depending on the operation of the drive part 51. Specifically, when the piston 53 operates and tilts, the drive rod 56 may be tilted, resulting in a possibility of single-sided contact.

[0025] According to the fluid control valve described in (6), the drive rod is divided into a first rod extending from the drive part and a second rod on the side of the valve body in the direction of contact separation. Furthermore, since the end of the second rod on the side of the first rod is a free end not connected to the first rod, the second rod is less affected by the operation of the drive part. That is, for example, when the drive part includes a piston, even if the piston tilts, the second rod is less affected by it and is less likely to tilt. Therefore, the occurrence of single-sided contact can be prevented.

[0026] (7) In the fluid control valve according to any one of (1) to (6) above, it is preferable to provide a sliding member that guides the drive along the direction of contact separation of the drive rod, and the sliding member is located outside the drive part.

[0027] In a fluid control valve (cylinder valve 50) according to the prior art, the driving along the direction of contact and separation of the driving rod 56 is guided by a sliding member (for example, a sliding bearing 60) provided in the driving unit 51. In such a configuration, since the distance between the sliding member (sliding bearing 60) and the valve body 65 is far, when the valve body 65 receives the pressure of the control fluid, the axis of the driving rod 56 is likely to wobble, and there is a risk of single-sided contact occurring.

[0028] (7) According to the fluid control valve described above, since the sliding member is located outside the driving unit, the sliding member can be brought closer to the valve body, and it is possible to minimize the wobbling of the axis of the driving rod when the valve body receives the pressure of the control fluid. Thereby, the occurrence of single-sided contact can be prevented.

Effect of the Invention

[0029] According to the fluid control valve of the present invention, it is possible to prevent the occurrence of single-sided contact of the valve body against the annular valve seat.

Brief Description of the Drawings

[0030] [Figure 1] It is a cross-sectional view of the fluid control valve according to the present embodiment. [Figure 2] It is a partially enlarged view of part A of FIG. 1 in a state where the valve body starts to contact the annular valve seat. [Figure 3] It is a partially enlarged view of part A of FIG. 1 in the valve closed state. [Figure 4] It is a cross-sectional view of the fluid control valve according to the prior art. <N

Mode for Carrying Out the Invention

[0031] An embodiment of the fluid control valve according to the present invention will be described in detail with reference to the drawings. Figure 1 is a cross-sectional view of the fluid control valve 1 according to this embodiment. In Figure 1, the vertical direction is the direction in which the valve body 34 contacts and separates from the annular valve seat 317 (contact and separation direction), with the upper side in the figure being called the separation direction and the lower side being called the contact direction. Figure 2 is a partially enlarged view of part A in Figure 1, in the state in which the valve body 34 has started to contact the annular valve seat 317. Figure 3 is a partially enlarged view of part A in Figure 1, in the valve closed state.

[0032] (Regarding the configuration of the fluid control valve) The fluid control valve 1 according to this embodiment is a cylinder valve that uses a high-pressure fluid (5 MPa or higher), such as high-pressure air used in automotive anti-lock braking systems or airtightness testing of hydraulic equipment, as the control fluid. However, its applications are not limited to automotive anti-lock braking systems or airtightness testing of hydraulic equipment. Furthermore, the control fluid is not limited to high-pressure air, but may also be a gas other than high-pressure air, or a liquid such as a beverage.

[0033] The fluid control valve 1 comprises an actuation unit 2 and a valve unit 3, and is constructed by stacking the actuation unit 2 on the side of the valve unit 3 in the direction of separation. The actuation unit 2 and the valve unit 3 will be described below.

[0034] (Regarding the drive unit) First, let's describe the drive unit 2. The drive unit 2 is an air cylinder that operates by receiving operating air, and its main components are a case body 21, a piston 23, and a guide member 25. The case body 21 also mainly consists of an upper cover member 211, a body 212, and a lower cover member 213.

[0035] The body portion 212 is made of, for example, an aluminum alloy and is formed in a cylindrical shape. The axial direction of the body portion 212 is parallel to the direction of contact and separation. The upper side (side in the direction of separation) and the lower side (side in the direction of contact) of the body portion 212 are open in the axial direction. The upper opening of the body portion 212 is closed by the upper cover member 211, and the lower opening of the body portion 212 is closed by the lower cover member 213, thereby forming a substantially cylindrical case body 21. The upper cover member 211 and the lower cover member 213 are made of, for example, an aluminum alloy.

[0036] The upper cover member 211 is formed in a roughly U-shape with an opening on the side facing the contact direction, and the guide member 25 is press-fitted and fixed into this opening. The guide member 25 has a cylindrical portion 251 that is coaxial with the cylindrical case body 21. The lower cover member 213 is provided with an insertion hole 213a that penetrates in the direction of contact and separation, coaxial with the case body 21. This cylindrical portion 251 and the insertion hole 213a are parts that guide the sliding of the piston 23 along the direction of contact and separation.

[0037] The inside of the case body 21 is a cylindrical space, which is the piston chamber 22. A piston 23 is loaded into the piston chamber 22 so as to be slidable along the direction of contact and separation.

[0038] The piston 23 is equipped with a disc-shaped piston portion 231. The axial direction of the piston portion 231 is parallel to the direction of contact and separation, and the piston portion 231 is located coaxially with the piston chamber 22, which is a cylindrical space. Due to this piston portion 231, the piston chamber 22 is divided into a first chamber 221 on the separation direction side and a second chamber 222 on the contact direction side. An O-ring 238 is attached to the outer circumferential surface of the piston portion 231, and this O-ring 238 maintains airtightness between the first chamber 221 and the second chamber 222 by being compressed between the outer circumferential surface of the piston portion 231 and the inner circumferential surface of the piston chamber 22.

[0039] Furthermore, the piston 23 includes a cylindrical shaft portion 232 projecting away from the piston portion 231, and a cylindrical first rod 233 projecting towards the contact direction from the piston portion 231. The piston portion 231, the shaft portion 232, and the first rod 233 are all located coaxially.

[0040] The shaft portion 232 is inserted into the cylindrical portion 251 of the guide member 25. An O-ring 237 is attached to the outer circumferential surface of the shaft portion 232, and this O-ring 237 is compressed between the outer circumferential surface of the shaft portion 232 and the inner circumferential surface of the cylindrical portion 251. This maintains airtightness in the space (third chamber 27) surrounded by the upper cover member 211, the cylindrical portion 251, and the shaft portion 232 of the piston 23. The airtightness of the third chamber 27 is also maintained by an O-ring 236 provided between the upper cover member 211 and the guide member 25.

[0041] The first rod 233 is inserted into the through hole 213a of the lower cover member 213. Here, the tip of the first rod 233 protrudes from the drive unit 2 and enters the valve unit 3. An O-ring 235 is attached to the outer surface of the first rod 233, and this O-ring 235 is compressed between the outer surface of the first rod 233 and the inner surface of the through hole 213a. This maintains the airtightness of the second chamber 222.

[0042] As described above, the shaft portion 232 is inserted into the cylindrical portion 251 and the first rod 233 is inserted into the through hole 213a, so that the cylindrical portion 251 and the through hole 213a hold the piston 23 in a double-supported state and guide the sliding of the piston 23 in the direction of contact and separation.

[0043] The sliding of the piston 23 in the contact and separation directions will be explained in detail. Sliding in the contact and separation directions can be divided into sliding in the contact direction and sliding in the separation direction.

[0044] First, let's explain the sliding of the piston 23 in the contact direction. Sliding in the contact direction is performed by compression coil springs 26A and 26B. The compression coil springs 26A and 26B are housed in the first chamber 221 in a compressed state by the end face on the side of the piston portion 231 that is separated (the upper end face in the figure) and the end face on the side of the guide member 25 that is in the contact direction (the lower end face in the figure). As a result, the compression coil springs 26A and 26B always apply a biasing force to the piston 23 in the contact direction (downward in the figure). This biasing force of the compression coil springs 26A and 26B causes the piston 23 to slide in the contact direction.

[0045] Next, the sliding of the piston 23 in the direction of separation will be described. Sliding in the direction of separation is performed by operating air supplied to the second chamber 222 of the drive unit 2. The operating air is supplied to the second chamber 222 using the supply port 211a, the third chamber 27, and the ventilation passage 234.

[0046] The supply port 211a is provided on the axis of the upper cover member 211, penetrating the upper cover member 211 in the direction of contact and separation. The supply port 211a connects the third chamber 27 to the outside of the drive unit 2. An operating air supply source (not shown) is also connected to the supply port 211a.

[0047] The ventilation passage 234 is provided opening at the tip of the shaft portion 232 of the piston 23. This ventilation passage 234 extends along the central axis of the piston 23 toward the first rod 233. Furthermore, near the base of the first rod 233 (the connection point between the first rod 233 and the piston portion 231), the ventilation passage 234 branches perpendicular to the central axis of the piston 23 and opens on the outer surface of the first rod 233, on the side further away from the O-ring 235 (the upper side in the figure). The ventilation passage 234 described above connects the third chamber 27 and the second chamber 222.

[0048] With the above configuration, the operating air is supplied to the second chamber 222 as follows. First, when the operating air is supplied from the supply source to the drive unit 2, the operating air flows into the third chamber 27 from the supply port 211a. Since the third chamber 27 is airtight due to the O-rings 236 and 237, the operating air that flows into the third chamber 27 passes through the ventilation passage 234 without leaking into the first chamber 221 and flows into the second chamber 222.

[0049] As described above, when operating air flows into the second chamber 222, the pressure inside the second chamber 222 increases. As a result, the piston portion 231 is subjected to pressure in the direction of separation, causing the piston 23 to slide in the direction of separation against the biasing force of the compression coil springs 26A and 26B.

[0050] (Regarding the valve section) Next, the valve section 3 will be described. The valve section 3 mainly consists of a valve body 31, an adapter 32, a second rod 33, and a valve element 34.

[0051] The adapter 32 is cylindrical and is located coaxially with the drive unit 2. A male threaded portion 322 is provided on the outer circumferential surface of the adapter 32 on the side facing the contact direction (the end facing the valve body 31), and this male threaded portion 322 is screwed into a female threaded portion 315 provided on the side facing the separation direction of the valve body 31 (the end facing the adapter 32). Furthermore, a male threaded portion 321 is provided on the outer circumferential surface of the adapter 32 on the side facing the separation direction (the end facing the drive unit 2), and this male threaded portion 321 is screwed into a female threaded portion 28 provided on the side facing the contact direction of the drive unit 2 (lower cover member 213) (the end facing the adapter 32). In this way, the valve unit 3 is connected to the drive unit 2.

[0052] The valve body 31 is made of metal, such as stainless steel, and includes an input passage 311 for supplying control fluid to the fluid control valve 1 and an output passage 312 for supplying control fluid from the fluid control valve 1. Furthermore, the valve body 31 has a cylindrical portion 313 that protrudes toward the side in the direction of separation (upward in the figure) from the drive unit 2 and the adapter 32, and is coaxial with the drive unit 2 and the adapter 32. This cylindrical portion 313 is located coaxially with the drive unit 2 and the adapter 32. The inner circumferential surface of the tip of the cylindrical portion 313 is the aforementioned female thread portion 315. The space on the inner circumferential side of the cylindrical portion 313 that is in contact with the female thread portion 315 is a valve chamber 314 that connects the input passage 311 and the output passage 312.

[0053] The valve chamber 314 and the input passage 311 are connected by a valve hole 316, which is provided coaxially with the cylindrical portion 313. Furthermore, an annular valve seat 317 is provided on the bottom surface of the valve chamber 314, protruding coaxially with the valve hole 316 toward the direction of separation. Since the annular valve seat 317 is integrally formed with the valve body 31, it is made of metal such as stainless steel, like the valve body 31. The annular valve seat 317 is tapered 317a on its outer surface toward the tip, causing it to narrow toward the tip. The tip surface of the annular valve seat 317 toward the direction of separation is the contact surface 317b (second contact surface) where the valve body 34, described later, contacts and separates. This contact surface 317b is a plane perpendicular to the direction of contact and separation.

[0054] The valve chamber 314 houses a valve body 34 that contacts and separates from the annular valve seat 317. The valve body 34 is held at the end of the second rod 33, which extends from the hollow portion of the adapter 32 to the valve chamber 314, on the side facing the contact direction.

[0055] Here, the configuration of the second rod 33 and the valve body 34 will be described in more detail. The second rod 33 is made of metal such as stainless steel and is formed in a substantially cylindrical shape. Together with the first rod 233, the second rod 33 functions as a drive rod 24 for bringing the valve body 34 into contact with and separating from the annular valve seat 317. The end face (tip surface 334a) of the second rod 33 on the separating direction side is in contact with the tip surface 233a of the first rod 233. Therefore, when the piston 23 is driven in the contact direction, the tip surface 233a of the first rod 233 presses against the tip surface 334a of the second rod 33, and the second rod 33 is driven in the contact direction. However, the end (upper end 334) of the second rod 33 on the separating direction side is a free end that is not connected to the first rod 233, with only its tip surface 334a in contact with the tip surface 233a of the first rod 233.

[0056] Furthermore, an annular sliding member 36 is fixed to the upper end 334 of the second rod 33, positioned coaxially with the second rod 33. The sliding member 36 is also equipped with a sliding bearing 37 on its outer circumferential surface. This sliding bearing 37 slides against the inner circumferential surface of the adapter 32, thereby allowing the sliding member 36 to guide the drive of the second rod 33 in the direction of contact and separation.

[0057] A compression coil spring 38 is in contact with the end face of the sliding member 36 on the side facing the contact direction. The compression coil spring 38 is compressed by the sliding member 36 and the stopper 39 which is located opposite the sliding member 36 on the side facing the contact direction. As a result, the compression coil spring 38 applies a biasing force to the sliding member 36 in the direction of separation. In other words, since the sliding member 36 is fixed to the second rod 33, the second rod 33 is biased in the direction of separation. Therefore, when the piston 23 is driven in the direction of separation, the biasing force of the compression coil spring 38 drives the second rod 33 in the direction of separation, following the piston 23 (first rod 233).

[0058] The end of the second rod 33 on the side facing the contact direction is an enlarged diameter portion 331, which has a larger diameter than the rest of the rod. A cylindrical retaining groove 332 for holding the valve body 34 is drilled in the enlarged diameter portion 331, extending in the direction away from the end face (lower end face) on the side facing the contact direction. This retaining groove 332 is located coaxially with the second rod 33. The surface of the retaining groove 332 on the side facing away from the contact direction is a concave spherical surface 333. The center C11 of this concave spherical surface 333 is located on the axis of the second rod 33.

[0059] The valve body 34 is formed in a substantially cylindrical shape and is divided into a large-diameter portion 34a on the side facing the separation direction (the side facing the second rod 331) and a small-diameter portion 34b on the side facing the contact direction (the side facing the annular valve seat 317), with the boundary being approximately the central part in the axial direction. The material of the valve body 34 is preferably a resin such as polyimide, with a compressive strength of 125 MPa or more. The end face of the valve body 34 on the side facing the contact direction is a contact surface 341 that contacts and separates from the annular valve seat 317. This contact surface 341 is a plane perpendicular to the contact and separation direction. The end face of the valve body 34 opposite to the contact surface 341 is a convex spherical surface 342 that bulges out toward the side facing the second rod 33 (the side facing the separation direction). The center C12 of this convex spherical surface 342 is located on the contact surface 341. In addition, the radius of the convex sphere 342 and the radius of the concave sphere 333 are the same. Therefore, when the convex sphere 342 is in contact with the concave sphere 333, the center C12 of the convex sphere 342 coincides with the center C11 of the concave sphere 333.

[0060] The concave spherical surface 333 and the convex spherical surface 342 are housed in the retaining groove 332 so as to face each other. Furthermore, an annular stepped portion 343 is formed due to the difference in diameter between the large diameter portion 34a and the small diameter portion 34b. The annular fixing member 35, which is screwed onto the enlarged diameter portion 331 of the second rod 33, catches on the annular stepped portion 343 of the valve body 34, thereby preventing the valve body 34 from falling out of the retaining groove 332.

[0061] The valve body 34 is held in the retaining groove 332 with play in the direction of contact and separation, and in a direction perpendicular to the direction of contact and separation. Specifically, a predetermined gap G11 is provided between the annular stepped portion 343 and the fixing member 35. This gap G11 ensures play in the direction of contact and separation. In addition, the diameter of the valve body 34 is smaller than the diameter of the retaining groove 332, and a predetermined gap G12 is provided between the outer circumferential surface of the valve body 34 and the inner circumferential surface of the retaining groove 332. This gap G12 ensures the play in the direction perpendicular to the direction of contact and separation described above. The size of this gap G12 is the value obtained by dividing the difference between the diameter of the retaining groove 332 and the diameter of the valve body 34 by 2.

[0062] (Operation and effects of fluid control valves) The fluid control valve 1, having the configuration described above, operates as follows. First, the opening operation of the fluid control valve 1, that is, the separation operation in which the valve body 34 separates from the annular valve seat 317, will be explained. When the drive unit 2 is not receiving operating air, the valve body 34 is in contact with the annular valve seat 317, as shown in Figure 1. In other words, the fluid control valve 1 is in the closed state.

[0063] In this state, when operating air is supplied to the drive unit 2, the fluid control valve 1 opens as follows. When operating air is supplied to the drive unit 2, it flows from the supply port 211a into the third chamber 27. The operating air that has flowed into the third chamber 27 then passes through the ventilation passage 234 and flows into the second chamber 222. When the operating air flows into the second chamber 222, the pressure inside the second chamber 222 increases. As a result, the piston portion 231 is subjected to pressure in the direction of separation, and the piston 23 slides in the direction of separation against the biasing force of the compression coil springs 26A and 26B.

[0064] When the piston 23 of the drive unit 2 slides in the apart direction due to the operating air, the tip surface 233a of the first rod 233 moves away from the tip surface 334a of the second rod 33, and the second rod 33 is driven in the apart direction by the biasing force of the compression coil spring 38. As the second rod 33 is driven in the apart direction, the valve body 34 held by the second rod 33 moves away from the annular valve seat 317, and the fluid control valve 1 opens.

[0065] Next, we will describe the closing operation of the fluid control valve 1, that is, the contact operation in which the valve body 34 comes into contact with the annular valve seat 317.

[0066] When the fluid control valve 1 is in the open state, that is, when the valve body 34 is separated from the annular valve seat 317, operating air is discharged from the second chamber 222 of the drive unit 2, causing the piston 23 of the drive unit 2 to slide in the contact direction due to the biasing force of the compression coil springs 26A and 26B.

[0067] When the piston 23 slides in the contact direction, the tip surface 233a of the first rod 233 presses against the tip surface 334a of the second rod 33 in the contact direction, so that the second rod 33 is driven in the contact direction against the biasing force of the compression coil spring 38. As a result of the second rod 33 being driven in the contact direction, the valve body 34 held by the second rod 33 comes into contact with the annular valve seat 317, and the fluid control valve 1 closes. It should be noted that since the biasing force of the compression coil springs 26A and 26B drives the second rod 33 against the biasing force of the compression coil spring 38, the spring load of the compression coil spring 38 must be weaker than the spring load of the compression coil springs 26A and 26B. Furthermore, since the fluid control valve 1 controls a high-pressure fluid (5 MPa or higher), such as high-pressure air, the spring loads of the compression coil springs 26A and 26B must be sufficient to allow the valve to close against the fluid pressure.

[0068] Since both the contact surface 341 of the valve body 34 and the contact surface 317b of the annular valve seat 317 are planes perpendicular to the direction of contact and separation, when the valve body 34 contacts the annular valve seat 317, the surfaces come into contact with each other. Therefore, compared to conventional fluid control valves (e.g., cylinder valve 50) in which the valve body and the annular valve seat are in line contact, the stress load on the valve body 34 due to repeated contact is reduced, and plastic deformation of the valve body 34 can be prevented.

[0069] Furthermore, when the piston 23 is driven in the contact direction, the axis of the piston 23 may wobble, potentially causing the piston 23 to tilt. However, the upper end 334 of the second rod 33 is a free end and is not connected to the first rod 233 extending from the piston 23 (i.e., the drive rod 24 is divided into the first rod 233 and the second rod 33 in the contact-to-separation direction). Therefore, even if the piston 23 tilts, the second rod 33 is less affected and less likely to tilt. Thus, uneven contact can be prevented.

[0070] Furthermore, the valve body 34 is subjected to pressure by the control fluid, which may cause the axis of the second rod 33 (drive rod 24) to wobble. The drive of the second rod 33 (drive rod 24) in the direction of contact and separation is guided by the sliding member 36, and since the sliding member 36 is located outside the drive unit 2 (specifically inside the adapter 32), the second rod 33 (drive rod 24) is guided at a position closer to the valve body 34 compared to conventional fluid control valves (for example, cylinder valve 50). Therefore, it is possible to minimize the wobble of the axis of the second rod 33 (drive rod 24). This makes it possible to prevent uneven contact.

[0071] Furthermore, due to manufacturing tolerances, it is not possible to completely eliminate the wobble of the axis of the second rod 33 (drive rod 24), which may cause uneven contact. However, with the fluid control valve 1, even if the axis of the second rod 33 (drive rod 24) is wobble, it is possible to prevent uneven contact. Specifically, the case in which the axis of the second rod 33 is wobble when the second rod 33 attempts to slide in the contact direction will be explained using Figures 2 and 3.

[0072] In Figure 2, the ideal axis of the second rod 33, assuming no deviation at all, is represented as the ideal axis CL11. The axis of the second rod 33 is also shown as axis CL21, which is tilted to the right relative to the ideal axis CL11 due to deviation. The angle of axis CL21 relative to the ideal axis CL11 is angle A11. In this case, the axis CL31 of the valve body 34 is assumed to coincide with the axis CL21 of the second rod 33.

[0073] Thus, when the second rod 33 slides in the contact direction and the axis CL21 is tilted to the right in the figure, when the valve body 34 attempts to contact the annular valve seat 317, the valve body 34 first contacts a portion of the entire circumference of the annular valve seat 317. Specifically, for example, as shown in Figure 2, the contact surface 341 of the valve body 34 contacts the contact surface 317b of the annular valve seat 317 on the right side in the figure, but not on the left side in the figure.

[0074] However, in addition to the fact that the convex spherical surface 342 of the valve body 34 is fitted onto the concave spherical surface 333 of the second rod 33 (i.e., the valve body 34 and the second rod 33 are in contact with each other's spherical surfaces), the valve body 34 is held by the second rod 33 with play in the direction of contact and separation due to the gap G11 and play perpendicular to the direction of contact and separation due to the gap G12. Therefore, when the driving force of the drive unit 2 is applied to the valve body 34 from the one-sided contact state shown in Figure 2, the convex spherical surface 342 slides along the concave spherical surface 333, and the valve body 34 can tilt with respect to the axis CL21 of the second rod 33. In other words, as shown in Figure 3, the valve body 34 rotates counterclockwise around the center C12 in Figure 2, and the axis CL31 of the valve body 34 becomes parallel to the ideal axis CL11. The rotation of the valve body 34 absorbs the tilt of the second rod 33, and the valve body 34 comes into contact with the entire circumference of the annular valve seat 317, thus preventing uneven contact of the valve body 34 with the annular valve seat 317.

[0075] The sizes of the gaps G11 and G12 are set to allow the valve body 34 to tilt to an extent that can absorb the amount of inclination of the axis CL21 of the second rod 33 (size of angle A11) due to manufacturing tolerances. For example, in this embodiment, angle A11 is 1.6 degrees, and the sizes of the gaps G11 and G12 are set so that the axis CL31 of the valve body 34 can tilt by 1.6 degrees relative to the axis CL21 of the second rod 331.

[0076] Furthermore, in the fluid control valve 1 according to this embodiment, the diameter D11 of the large-diameter portion 34a of the valve body 34 is set to be larger than the diameter D21 of the contact surface 317b of the annular valve seat 317. As a result, the convex spherical surface 342 and the concave spherical surface 333 face each other over a wider area than the diameter D21 of the contact surface 317b of the annular valve seat 317. This allows the convex spherical surface 342 to slide smoothly. If the convex spherical surface 342 and the concave spherical surface 333 face each other over a narrower area than the diameter D21 of the contact surface 317b, that is, if they face each other on the inner circumference side of the contact surface 317b, the convex spherical surface 342 will not slide smoothly when the valve body 34 receives force from the annular valve seat 317, so this is prevented.

[0077] As described above, the fluid control valve 1 according to this embodiment is (1) A fluid control valve 1 comprising a metal annular valve seat 317, a resin valve body 34 that contacts and separates with respect to the annular valve seat 317, a drive rod 24 that extends along the direction of contact and separation on the side of the valve body 34 opposite to the annular valve seat 317 and holds the valve body 34, and a drive unit 2 for performing contact and separation by driving the drive rod 24 along the direction of contact and separation, wherein the valve body 34 has a convex spherical surface 342 that bulges toward the drive rod 24 at the end face opposite the contact surface 341 that contacts the annular valve seat 317, the drive rod 24 has a concave spherical surface 333 that is opposite the convex spherical surface 342 and is fittable with the convex spherical surface 342 and has a center C11 on the axis of the drive rod 24, and the valve body 34 is held with play in the direction of contact and separation and in a direction perpendicular to the direction of contact and separation.

[0078] According to the fluid control valve 1 described in (1), the valve body 34 has a convex spherical surface 342 on the opposite end face of the contact surface 341 that abuts against the annular valve seat 317, which bulges out toward the drive rod 24; the drive rod 24 has a concave spherical surface 333 opposite to the convex spherical surface 342, which is fittable with the convex spherical surface 342 and has its center C11 on the axis of the drive rod 24; and the valve body 34 is held with play in the direction between contact and separation and in a direction perpendicular to the direction between contact and separation. As a result, when the convex spherical surface 342 of the valve body 34 is in contact with the concave spherical surface 333 of the drive rod 24, the convex spherical surface 342 can slide along the concave spherical surface 333. In other words, the valve body 34 can be tilted with respect to the axis of the drive rod 24.

[0079] When the drive unit 2 drives the drive rod 24 to bring the valve body 34 into contact with the annular valve seat 317, if the axis of the drive rod 24 is misaligned and the drive rod 24 is tilted with respect to the contact-to-separation direction, the valve body 34 will first come into contact with a portion of the entire circumference of the annular valve seat 317. If the drive force of the drive unit 2 is then applied to the valve body 34, as described above, the convex spherical surface 342 will slide along the concave spherical surface 333, causing the valve body 34 to tilt with respect to the axis of the drive rod 24. This tilt of the valve body 34 absorbs the tilt of the drive rod 24, making it possible to prevent uneven contact of the valve body 34 with the annular valve seat 317. Furthermore, because uneven contact is prevented by the tilt of the valve body 34, there is no need to press the valve body 34 against the annular valve seat 317 with strong force to prevent uneven contact, and the load on the drive unit 2 can be kept low.

[0080] In order for the convex spherical surface 342 to slide smoothly along the concave spherical surface 333, it is preferable that the convex spherical surface 342 and the concave spherical surface 333 have approximately the same radius in the fluid control valve 1 described in (2)(1).

[0081] (3) In the fluid control valve 1 described in (1) or (2), it is preferable that the center C12 of the convex spherical surface 342 is located on the contact surface 341.

[0082] The sliding of the convex spherical surface 342 is achieved when the valve body 34 contacts the annular valve seat 317 and receives a force. In order to slide efficiently with a smaller force, it is desirable that the position of the center of sliding of the convex spherical surface 342 in the direction between contact and separation be as close as possible to the annular valve seat 317 that applies force to the valve body 34. According to the fluid control valve 1 described in (3), since the center C12 of the convex spherical surface 342 is located on the contact surface 341, the position of the center of sliding of the convex spherical surface 342 in the direction between contact and separation is close to the annular valve seat 317. Therefore, it is possible to slide the convex spherical surface 342 efficiently with a smaller force.

[0083] (4) In the fluid control valve 1 described in any one of (1) to (3), it is preferable that the contact surface 341 is a plane perpendicular to the direction of contact and separation, and that the second contact surface (contact surface 317b) of the annular valve seat 317 that contacts the contact surface 341 is a plane parallel to the contact surface 341.

[0084] If the valve body 34 and the annular valve seat 317 repeatedly come into contact by line contact, the valve body 34 may undergo plastic deformation, potentially reducing the sealing performance when the valve is closed. According to the fluid control valve 1 described in (4), when the valve body 34 and the annular valve seat 317 come into contact, they make contact surface to surface, thus preventing plastic deformation of the valve body 34 due to line contact and maintaining stable sealing performance when the valve is closed.

[0085] (5) In the fluid control valve 1 described in any one of (1) to (4), it is preferable that the convex spherical surface 342 and the concave spherical surface 333 face each other over a wider area than the diameter D21 of the second contact surface (contact surface 317b) that contacts the contact surface 341 of the annular valve seat 317.

[0086] If the convex spherical surface 342 and the concave spherical surface 333 face each other over a range narrower than the diameter D21 of the second contact surface (contact surface 317b), that is, if they face each other on the inner circumference side of the second contact surface (contact surface 317b), the sliding of the convex spherical surface 342 will not be smooth when the valve body 34 receives force from the annular valve seat 317. According to the fluid control valve 1 described in (5), the convex spherical surface 342 and the concave spherical surface 333 face each other over a range wider than the diameter D21 of the second contact surface (contact surface 317b) that contacts the contact surface 317b of the annular valve seat 317, so the sliding of the convex spherical surface 342 is smooth.

[0087] (6) In the fluid control valve 1 described in any one of (1) to (5), it is preferable that the drive rod 24 is divided in the direction between contact and separation into a first rod 233 extending from the drive unit 2 and a second rod 33 on the valve body 34 side, and that the end of the second rod 33 on the first rod 233 side (upper end 334) is a free end that is not connected to the first rod 233.

[0088] In conventional fluid control valves (cylinder valves 50), there was a risk of uneven contact occurring depending on the operation of the drive unit 51. Specifically, the tilting of the piston 53 during operation could cause the drive rod 56 to tilt, potentially resulting in uneven contact.

[0089] According to the fluid control valve 1 described in (6), the drive rod 24 is divided in the direction of contact and separation into a first rod 233 extending from the drive unit 2 and a second rod 33 on the valve body 34 side. Furthermore, the end of the second rod 33 on the first rod 233 side (upper end 334) is a free end that is not connected to the first rod 233, so the second rod 33 is less affected by the way the drive unit 2 operates. In other words, for example, if the drive unit 2 is equipped with a piston 23, even if the piston 23 is tilted, the second rod 33 is less affected and less likely to tilt. Thus, it is possible to prevent uneven contact.

[0090] (7) In the fluid control valve 1 described in any one of (1) to (6), it is preferable that a sliding member 36 is provided to guide the drive of the drive rod 24 (second rod 33) along the direction between contact and separation, and that the sliding member 36 is located outside the drive unit.

[0091] In a conventional fluid control valve (cylinder valve 50), a sliding member (for example, a sliding bearing 60) provided in the drive unit 51 guides the drive of the drive rod 56 along the direction between contact and separation. In such a configuration, because the distance between the sliding member (sliding bearing 60) and the valve body 65 is large, the axis of the drive rod 56 is prone to wobbling when the valve body 65 is subjected to the pressure of the control fluid, which may cause uneven contact.

[0092] According to the fluid control valve 1 described in (7), since the sliding member 36 is located outside the drive unit 2, the sliding member 36 can be brought closer to the valve body 34, and the wobble of the drive rod 24 (second rod 33) when the valve body 34 is subjected to the pressure of the control fluid can be minimized. This prevents the occurrence of uneven contact.

[0093] The above embodiments are merely illustrative and do not limit the present invention in any way. Therefore, the present invention can naturally be improved and modified in various ways without departing from its essence. For example, although the fluid control valve 1 according to this embodiment is described as a normally closed type that opens when operating air is supplied, it may also be a normally open type that closes when operating air is supplied. [Explanation of symbols]

[0094] 1. Fluid control valve 2 Drive unit 24 drive rods 34 Valve body 317 Annular valve seat 333 Concave spherical surface 341 Contact surface 342 Convex spherical surface

Claims

1. A metal annular valve seat, A resin valve body that contacts and separates from the aforementioned annular valve seat, A drive rod extends along the direction between the contact and separation of the valve body on the side of the valve body opposite to the annular valve seat, and holds the valve body. The drive rod is driven along the direction of the contact and separation interval, thereby providing a drive unit for performing the contact and separation interval, In a fluid control valve equipped with, The valve body is, The end face opposite to the contact surface that abuts the annular valve seat is a convex spherical surface that bulges out toward the drive rod. The aforementioned drive rod is Opposite the convex spherical surface, there is a concave spherical surface that is compatible with the convex spherical surface and has its center on the axis of the drive rod. The valve body is held with play in the direction between contact and separation and in a direction perpendicular to the direction between contact and separation. A fluid control valve characterized by the following.

2. In the fluid control valve according to claim 1, The convex spherical surface and the concave spherical surface have approximately the same radius. A fluid control valve characterized by the following.

3. In the fluid control valve according to claim 1 or 2, The center of the convex spherical surface is located on the aforementioned contact surface. A fluid control valve characterized by the following.

4. In the fluid control valve according to claim 1 or 2, The contact surface is a plane perpendicular to the direction between contact and separation. The second contact surface of the annular valve seat that contacts the contact surface is a plane parallel to the contact surface. A fluid control valve characterized by the following.

5. In the fluid control valve according to claim 1 or 2, The convex spherical surface and the concave spherical surface face each other over a wider area than the diameter of the second contact surface that contacts the contact surface of the annular valve seat. A fluid control valve characterized by the following.

6. In the fluid control valve according to claim 1 or 2, The drive rod is divided into a first rod extending from the drive unit and a second rod on the valve body side in the direction between contact and separation. The end of the second rod on the first rod side is a free end that is not connected to the first rod. A fluid control valve characterized by the following.

7. In the fluid control valve according to claim 1 or 2, The drive rod is provided with a sliding member that guides the drive along the direction between contact and separation. The sliding member is located outside the drive unit. A fluid control valve characterized by the following.

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