valve

Abstract

When a coil spring with a pigtail in the seat coil is used in a valve, variations and inclinations in the load applied from the coil spring to the valve body are reduced. [Solution] In the valve (1), the coil spring (30) has a seat winding portion (32) in which the winding diameter decreases from one end (32A) to the other end (32B). A first portion within a predetermined number of turns from one end (32A) abuts against the inner circumferential surface (23A) of the insertion hole (23), and the other end (32B) is spaced further away from the inner circumferential surface (23A) than the first portion.

Description

Technical Field

[0001] This disclosure relates to a valve.

Background Art

[0002] Patent Document 1 discloses a valve including a valve seat, a valve body, and a coil spring that biases the valve body toward the valve seat. A coil spring having a pigtail in the seat winding portion is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when a coil spring having a pigtail in the seat winding portion is adopted for a valve, the load applied from the coil spring to the valve body may vary or the coil spring may tilt. One aspect of this disclosure aims to reduce the variation and tilt of the load applied from a coil spring to a valve body when the coil spring having a pigtail in the seat winding portion is adopted for the valve.

Means for Solving the Problems

[0005] To solve the above problems, a valve according to one aspect of the present disclosure comprises a valve seat, a valve body, and a coil spring that biases the valve body to the valve seat, wherein the coil spring has an effective winding portion that functions as a spring and a seat winding portion at one end connected to the effective winding portion and at the other end which is the end of the coil spring, the valve body has a first surface facing the valve seat and a second surface located on the opposite side of the first surface, the second surface has an insertion hole into which the coil spring is inserted, the winding diameter of the seat winding portion decreases from one end to the other end, a first portion within a predetermined number of turns from the one end abuts the inner circumferential surface of the insertion hole, and the other end side is spaced further away from the inner circumferential surface than the first portion. [Effects of the Invention]

[0006] According to one aspect of this disclosure, when a coil spring having a pigtail in the seat winding portion is used in a valve, variations and inclinations in the load applied from the coil spring to the valve body can be reduced. [Brief explanation of the drawing]

[0007] [Figure 1] This is a cross-sectional view showing one example of the configuration of a valve according to Embodiment 1 of this disclosure. [Figure 2] This diagram is used to explain the positional relationship between the inner circumferential surface of the insertion hole and the first seating portion. [Figure 3] This is a plan view taken from a direction perpendicular to the AA cross-section shown in Figure 2. [Figure 4] This figure shows the bottom shape of the insertion hole according to Embodiment 2 of this disclosure. [Modes for carrying out the invention]

[0008] [Embodiment 1] Figure 1 is a cross-sectional view showing an example of the configuration of a valve according to Embodiment 1 of the present disclosure. The valve 1 shown in Figure 1 comprises a housing 10, a valve body 20, a coil spring 30, a valve seat 40, and a valve stem 50. The valve 1 opens and closes a flow path from an inlet communicating with the housing 10 to a discharge port communicating with the valve seat 40.

[0009] Valve 1, shown in Figure 1, has a closed state, a first open state, and a second open state. In Figure 1, valve 1 is in the closed state, and the flow path is closed. When valve 1 transitions to the first open state and the second open state, the flow path is opened. The second open state allows more liquid to flow than the first open state.

[0010] The housing 10 is cylindrical and fixed to the valve seat 40. Inside the housing 10, the valve seat 40 defines a housing 11 that accommodates the valve body 20 and the coil spring 30.

[0011] The valve body 20 is cylindrical and slidably mounted within the housing 11. A liquid flow path is defined between the valve body 20 and the housing 11. In Figure 1, the valve body 20 is in the closed position, with its first surface 21, which faces the valve seat 40, in contact with the valve seat 40, thus closing the liquid flow path from the housing 11 to the valve seat 40. When the first surface 21 separates from the valve seat 40, the valve 1 transitions to the second open state.

[0012] The valve body 20 has a second surface 22 opposite to the first surface 21. An insertion hole 23 into which a coil spring 30 is inserted is open on the second surface 22. The coil spring 30 is a compression spring that biases the valve body 20 to the valve seat 40. The coil spring 30 is formed, for example, by winding a wire with a circular cross-section. The coil spring 30 has a first seat winding portion 32 and a second seat winding portion 33 at both ends of the effective winding portion 31 that functions as a spring. The second seat winding portion 33 is in contact with the bottom surface 12 of the housing 10. One end 32A of the first seat winding portion 32 is connected to the effective winding portion 31, and the other end 32B is the end of the coil spring 30. The winding diameter of the first seat winding portion 32 is smaller at the other end 32B than at the one end 32A. That is, the first seat winding portion 32 has a so-called pigtail.

[0013] The insertion hole 23 extends from the second surface 22 to the first surface 21, and the coil spring 30 is inserted into it. The diameter of the insertion hole 23 decreases as it approaches the first surface 21. The insertion hole 23 has an inner circumferential surface 23A on a part of its side surface that abuts against the first seat winding portion 32 of the coil spring 30. The relationship between the insertion hole 23 and the first seat winding portion 32 will be described in detail later using Figures 2 and 3.

[0014] The valve body 20 has a flow path 24 inside the insertion hole 23 and a cover 25 that opens and closes the flow path 24. The flow path 24 is provided between the bottom surface of the insertion hole 23 and the first surface 21. The flow path 24 is formed by the communication of a first flow path 24A provided on the inner circumferential surface 23A side of the insertion hole 23 and a second flow path 24B provided on the first surface 21 side. The first flow path 24A has a larger hole diameter than the second flow path 24B, and the cover 25 is housed inside it. The cover 25 is, for example, ball-shaped and is held inside the insertion hole 23 by the pigtail on the other end 32B side of the first seat winding portion 32. In Figure 1, the cover 25 is in the closed valve position and is in contact with the opening of the second flow path 24B from the first flow path 24A side. When the cover 25 moves away from the opening of the second flow path 24B, the valve 1 transitions to the first open valve state. The second channel 24B has a taper 26 at the opening that is located in the center of the first surface 21.

[0015] The valve seat 40 is cylindrical and allows liquid to flow through its interior. Inside the valve seat 40 is a valve stem 50 that operates the valve body 20. The valve stem 50 has a first projection 51 formed to be insertable into the second flow path 24B and a second projection 52 formed to be in contact with the first surface 21. The valve stem 50 is slidably mounted inside the valve seat 40 by a predetermined driving force. The predetermined driving force is, for example, an electric motor.

[0016] When the valve rod 50 slides inside the valve seat 40 toward the valve body 20, the first protrusion 51 is inserted into the second flow path 24B along the taper 26. When the valve rod 50 is driven a predetermined amount toward the valve body 20, the first protrusion 51 abuts against the lid body 25. When the valve rod 50 is further driven toward the valve body 20, the first protrusion 51 separates the lid body 25 from the opening of the second flow path 24B, transitioning the valve 1 to the first open state.

[0017] When the valve rod 50 is further driven toward the valve body 20, the second protrusion 52 abuts against the first surface 21 of the valve body 20. When the valve rod 50 is further driven against the spring load of the coil spring 30, the valve rod 50 separates the first surface 21 of the valve body 20 from the valve seat 40, transitioning the valve 1 to the second open state.

[0018] When the valve rod 50 is driven away from the valve body 20 or when the driving force for driving the valve rod 50 is lost, the second protrusion 52 separates from the first surface 21 of the valve body 20, and the valve body 20 is returned to the closed position by the spring load of the coil spring 30. When the valve rod 50 is further driven away from the valve body 20 and the first protrusion 51 separates from the lid body 25, the lid body 25 is returned to the closed position.

[0019] FIG. 2 is a diagram used to explain the positional relationship between the inner peripheral surface of the insertion hole and the first seat winding portion. FIG. 2 shows a view of the coil spring 30 from the first flow path 24A side. In FIG. 2, the illustration of the insertion hole 23 is omitted from the perspective of drawing visibility. FIG. 3 is a plan view seen from a direction orthogonal to the A-A cross-section shown in FIG. 2.

[0020] For the first seat winding portion 32 of the coil spring 30, the first part within the range of a predetermined number of windings from one end 32A abuts against the inner peripheral surface 23A. The predetermined number of windings is not less than half a winding and not more than one winding, for example, 3 / 4 winding. In FIG. 3, two contact points 32C included in the first part are shown to represent the first part. As shown in FIG. 2, the two contact points 32C are separated by half a winding from each other. The A-A cross-section is a plane passing through the two contact points 32C and parallel to the central axis 31A of the effective number of windings portion 31.

[0021] As shown in Figure 3, the inner circumferential surface 23A of the insertion hole 23 is funnel-shaped. In the cross-sectional view AA, the two contact points 32C are located on two line segments that represent the inner circumferential surface 23A. Let θ1 be the smaller of the angles formed by these two line segments.

[0022] Furthermore, in Figure 3, tangent lines 320 are drawn from two points 32C on the first seat winding portion 32 that abuts the inner circumferential surface 23A of the insertion hole 23. If the smaller of the angles formed by these two tangent lines 320 is denoted as θ2, then θ2 is greater than θ1. In Figure 3, the tangent lines 320 are externally tangent to the portion of the first seat winding portion 32 that is on the other end 32B side of the two points 32C.

[0023] When attempting to bring the first seat coil portion 32, which has a pigtail, into contact with a surface perpendicular to the central axis 23B of the insertion hole 23, the portion of the pigtail that contacts that surface may be recessed toward one end 32A. In this case, the magnitude and direction of the load that the coil spring 30 applies to the valve body 20 will vary depending on how the pigtail is recessed. Furthermore, if the opening of the first channel 24A is widened so that the pigtail does not come into contact with it, the surface area that the first seat winding portion 32 can contact becomes too narrow, and there is a risk that one end 32A of the first seat winding portion 32 may fall into the first channel 24A.

[0024] The spring load of the coil spring 30 must satisfy at least the following two conditions: (1) When valve 1 is closed, the spring load of coil spring 30 is greater than the resistance force applied by the liquid trying to flow through the gap between the first surface 21 and valve seat 40. (2) When the valve 1 is brought to the second open state, the spring load of the coil spring 30 is less than the driving force that drives the valve stem 50. With a portion of the pigtail of the first seat coil 32 recessed toward one end 32A, and the spring load varying, it was difficult to design the valve 1 so that these conditions would be met.

[0025] As shown in Figure 3, by designing the insertion hole 23 and the coil spring 30 so that θ2 > θ1, the portion of the first seat winding 32 closer to the other end 32B than the two points 32C is spaced apart from the inner circumferential surface 23A of the insertion hole 23. This reduces the amount by which the pigtail is recessed toward one end 32A, and the variation in spring load is reduced.

[0026] [Embodiment 2] Other embodiments of this disclosure are described below. For the sake of clarity, components having the same function as those described in the above embodiments are denoted by the same reference numerals, and their descriptions are not repeated.

[0027] The valve 1 according to Embodiment 2 differs from Embodiment 1 in that the inner circumferential surface 23A of the insertion hole 23 is curved. Figure 4 is a diagram showing the bottom shape of the insertion hole according to Embodiment 2 of this disclosure. The insertion hole 23 according to Embodiment 2 shown in Figure 4 has a curved inner circumferential surface 23A. θ1 according to Embodiment 2 is the smaller of the angles formed by two tangents that externally tangent to the two contact points 32C that the first seat winding portion 32 abuts against the inner circumferential surface 23A of the insertion hole 23 according to Embodiment 2.

[0028] The inner circumferential surface 23A of the insertion hole 23 according to Embodiment 2 can be designed to have any curved shape, provided that the other end 32B is spaced further away from the first seat winding portion 32 than the portion that contacts the two points 32C of the first seat winding portion 32.

[0029] [Variation] In the above embodiment 1, as shown in Figure 3, the inner circumferential surface 23A of the insertion hole 23 was inclined at a constant angle up to the opening of the first flow path 24A. However, the inclination angle of the inner circumferential surface 23A of the insertion hole 23 may be changed in stages according to the distance from the opening of the first flow path 24A. For example, the inclination angle may be changed such that the apex angle θ1 of the cone including the inner circumferential surface 23A of the insertion hole 23 becomes smaller as it approaches the opening of the first flow path 24A.

[0030] In embodiments 1 and 2 described above, the valve body 20 is assumed to have a flow path 24 and a cover 25 inside the insertion hole 23, but it is not necessary for the valve body 20 to have a flow path 24 and a cover 25. If the valve body 20 does not have a flow path 24 and a cover 25, the first projection 51 on the valve stem 50 is not necessary.

[0031] The shape of the lid 25 does not have to be ball-shaped, as long as it can be accommodated in the first flow path 24A and can open and close the flow path 24.

[0032] 〔summary〕 A valve according to one aspect of the present disclosure comprises a valve seat, a valve body, and a coil spring for biasing the valve body to the valve seat, wherein the coil spring has an effective winding portion that functions as a spring and a seat winding portion at one end connected to the effective winding portion and at the other end which is the end of the coil spring, the valve body has a first surface facing the valve seat and a second surface located on the opposite side of the first surface, the second surface has an insertion hole into which the coil spring is inserted, the winding diameter of the seat winding portion decreases from one end to the other end, a first portion within a predetermined number of turns from the one end abuts the inner circumferential surface of the insertion hole, and the other end side of the first portion is spaced further away from the inner circumferential surface. The seat winding portion of the coil spring has one end connected to the effective number of turns, and the winding diameter from that end to the other end is smaller. In other words, it has a pigtail. The seat winding portion of the coil spring has a first portion within a predetermined number of turns from one end that abuts the inner surface of the insertion hole, and the other end is spaced away from the inner surface. Because the other end of the seat winding portion is spaced away from the inner surface from the first portion, variations and inclinations in the spring load caused by the pigtail of the coil spring being concave can be suppressed.

[0033] In one aspect of the present disclosure, the valve, in the above embodiment, has an insertion hole whose diameter decreases as it approaches its bottom surface, a predetermined number of turns of half a turn or more and 1 turn or less, and in a cross-sectional view of the insertion hole and the seat winding portion cut by a plane parallel to the central axis of the effective number of turns portion, passing through two points in the first portion that are separated by half a turn from each other, the two points are located on two line segments indicating the inner circumferential surface, the other end of the seat winding portion is tangent to two tangents that circumscribe the seat winding portion at the two points, or is located on the effective number of turns portion side of the two tangents, and the smaller of the angles formed by the two tangents that circumscribe the seat winding portion at the two points is larger than the smaller of the angles formed by the two line segments. In order to bring the coil spring into contact with the inner surface of the insertion hole, the diameter of the insertion hole decreases as it approaches its bottom. When the diameter of the insertion hole decreases as it approaches the bottom, there is a risk of contact with the other end of the coiled portion beyond the first portion. However, since the smaller of the angles formed by the two tangent lines that circumscribe the coiled portion at the two points mentioned above is larger than the smaller of the angles formed by the two line segments mentioned above, even if the diameter of the insertion hole decreases as it approaches the bottom, the other end of the coiled portion beyond the first portion can be kept away from the inner surface of the insertion hole.

[0034] In one aspect of the present disclosure, the valve body has a flow path provided between the bottom surface of the insertion hole and the first surface, and a cover that opens and closes the flow path, wherein the other end of the seat coil portion, beyond the first portion, holds the cover inside the insertion hole. If the coil spring does not have a so-called pigtail, where the winding diameter decreases from one end to the other, a separate stopper is required between the coil spring and the cover. By holding the cover at the end of the coil spring beyond the first portion, a separate stopper is not required, allowing the valve to be made smaller by the amount of the stopper, contributing to reduced parts costs and assembly man-hours.

[0035] [Additional Notes] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure. [Explanation of Symbols]

[0036] 1 valve 20 valve body 21 Page 1 22 Side 2 23 Insertion hole 23A Inner surface 30 coil springs 31 Effective winding section 31A center axis 32. Section 1 (Section 3) 32A one end 32B Other end 40 valve seats

Claims

1. A valve comprising a valve seat, a valve body, and a coil spring that biases the valve body to the valve seat, The coil spring has an effective winding portion that functions as a spring, and a seated winding portion, one end of which is connected to the effective winding portion and the other end of which is the end of the coil spring. The valve body has a first surface facing the valve seat and a second surface located on the opposite side of the first surface, and the second surface has an insertion hole into which the coil spring is inserted. The aforementioned winding portion has a winding diameter that decreases from one end to the other end, a first portion within a predetermined number of turns from the one end abuts the inner circumferential surface of the insertion hole, and the other end portion is spaced further away from the inner circumferential surface than the first portion, in a valve.

2. The diameter of the insertion hole decreases as it approaches the bottom surface. The predetermined number of turns is half a turn or more and one turn or less. In the cross-sectional view of the insertion hole and the seat winding portion, obtained by cutting through two points in the first portion that are separated by half a turn from each other and with a plane parallel to the central axis of the effective turn portion, The two points mentioned above are located on the two line segments that represent the inner circumferential surface, Of the aforementioned winding portion, the end on the other side of the two points is tangent to the two tangents that tangent to the winding portion at the two points, or is located on the effective winding portion side of the two tangents. The valve according to claim 1, wherein the smaller of the angles formed by the two tangent lines that circumscribe the seat coil portion at the two points is greater than the smaller of the angles formed by the two line segments.

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