JP2023020681A - actuator - Google Patents

Abstract

To provide an actuator capable of retaining a shaft center of a piston even in an actuator mounted in piping of a large flow rate and having a large piston diameter.SOLUTION: An actuator includes: an actuator cap 3 defining a cylinder 30 inside; a piston 2 kept into slide-contact with the cylinder 30 via a slide body 20; a stem 4 connected to the piston 2 and engaged with a valve element 6; an elastic member 5 pressing and energizing the piston 2 to one side; and a working fluid supply port 30A for supplying a working fluid in a direction against the pressing of the elastic member 5. A peripheral projection is formed on an outer peripheral surface of the piston 2, and the slide body 20 in which an outer peripheral surface and an inner peripheral surface are formed into a parallel arc shape and which has a groove portion formed on the inner peripheral surface, is fitted to the peripheral projection of the piston 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to an actuator for operating a valve body of a valve that opens and closes a flow path, and more particularly to an actuator made of resin.

A flow path connected to the pipe and a valve seat acting as a weir are provided in the middle of the pipe through which the fluid flows. An on-off valve, such as a diaphragm valve, which operates a valve body that contacts and separates from the valve seat, is operated by the working fluid. Actuators are used. The actuator includes an actuator cap whose interior is a cylinder, a piston that slides in contact with the cylinder of the actuator cap, an elastic member such as a spring that biases the piston in one direction, and an elastic member that resists the pressing force of the elastic member. A cylinder having a working fluid supply port for supplying working fluid for moving a piston into a cylinder is widely used. A piston that moves in the cylinder chamber is provided with a sealing member such as an O-ring to isolate a space in which the elastic member is arranged and a space in which the working fluid is supplied. (See Patent Document 1, for example).

If the flow rate of the fluid flowing through the flow passage is small and the pipe diameter is small, the valve seat, the valve body, and the actuator itself can also be made small. , can keep the axis center. However, when used in piping with a large flow rate, the actuator also has a large diameter, and the elastic force of the O-ring alone cannot correct the inclination and eccentricity of the shaft center due to the inclination of the spring that biases the piston in one direction. It becomes difficult to keep in place and the piston and cylinder can come into contact, wear and scratch.

In this way, when it is difficult to accurately maintain the axial center of the piston, the piston is provided with a wear ring in addition to the seal member to maintain the axial center. As described in Patent Document 2, a wear ring is generally an annular training member having a cut portion, and is used by being engaged with a groove portion formed on the outer peripheral surface of a piston.

Japanese Patent Application Laid-Open No. 2015- JP 2010-127387 A

A wear ring having a cut portion, which is commonly used, is not completely fixed to the groove portion of the piston, and depending on the shape of the cut portion, the load capacity may be lowered and the durability may be deteriorated. In addition, the market demanded lighter and cheaper actuators, and the inventors of the present invention also changed the design of the actuator by making each part of the actuator made of resin. cannot be formed, grooving is required after molding, and there is a problem that the demand for cost reduction cannot be met.

The present invention has been made in view of such a point, and provides an actuator having a highly durable bearing portion without using a wear ring having a cut portion that is commonly used, and having a shaft center that does not shift even if it has a large diameter. intended to provide It is another object of the present invention to provide an actuator having a bearing instead of a wear ring suitable for a piston molded by injection molding.

An actuator according to the present invention, which has been made to solve the above problems,
An actuator that operates a valve body disposed in a body that includes a flow path and a valve seat, and that contacts the valve seat to block communication of a fluid flowing through the flow path,
an actuator cap with a cylinder inside;
a piston in sliding contact with the cylinder via a sliding body;
a stem coupled to the piston and engaged with the valve body;
an elastic member that presses and biases the piston in one direction;
a working fluid supply port for supplying working fluid in a direction against the pressing force of the elastic member, wherein a circumferential projection is formed on the outer peripheral surface of the piston,
The sliding body has a groove on its inner surface for fitting into the circumferential projection, and a plurality of grooves are arranged in the circumferential direction of the outer peripheral surface of the piston.

The actuator of the present invention can be easily attached and improved in durability by fitting a plurality of sliding bodies having grooves on the inner peripheral surface to the circumferential protrusions on the outer peripheral surface of the piston.

In this case, the piston may be made of a resin that is divided into two parts in the axial direction by injection molding. Circumferential projections on the outer peripheral surface can be easily formed by injection molding in which the cylinder is divided into two parts in the axial direction.

Furthermore, in this case, the actuator cap and stem can be made of resin.

According to the actuator of the present invention, it is provided with a highly durable bearing portion, a sliding body suitable for a piston molded by injection molding, and an actuator that does not shift its axis even if it has a large diameter. be able to.

FIG. 4 is a cross-sectional front view showing a valve open state in which an actuator according to the present invention is attached to a diaphragm valve; It is a cross-sectional front view which shows the same valve closed state. The piston of the same actuator is shown, (a) is a plan view, (b) is an XX cross-sectional view of (a), and (c) is a YY cross-sectional view of (a). The piston and sliding body of the same actuator are shown, (a) is a plan view, and (b) is a YY sectional view of (a). It is a perspective view which shows the piston and sliding body of the same actuator.

A preferred embodiment of an actuator according to the present invention will be described below with reference to the drawings. Unless otherwise specified, the shape of the component parts described in this embodiment, their relative arrangement, etc. are not intended to limit the scope of the present invention, but are merely illustrative examples. For the sake of convenience, the directions of members and the like may be referred to as up, down, left, and right depending on the direction on the drawings, but these do not limit the scope of the present invention.

<Embodiment 1>
The figure shows an actuator according to the present invention. 1 and 2 show cross-sectional front views of an actuator 1 of the present invention attached to a diaphragm valve, with FIG. 1 showing the valve open state and FIG. 2 showing the valve closed state.

The actuator 1 is arranged in a body 7 having a valve seat 70 comprising an inflow channel 71, an outflow channel 72, and a weir. Actuator cap 3 having a cylinder 30 inside, and piston 2 slidingly contacting cylinder 30 via sliding body 20. , a stem 4 connected to the piston 2 and engaged with the valve body 6; an elastic member 5 for pushing the piston 2 in one direction; and a working fluid supply port 30A

A sliding body 20 having a circumferential projection 2a formed on the outer peripheral surface of the piston 2, an arcuate shape in which the outer peripheral surface 20b and the inner peripheral surface 20c are parallel, and a groove portion 20a formed in the inner peripheral surface 20c. , and the circumferential projection 2a. The width dimension h1 of the circumferential projection and the width dimension h2 of the groove portion 20a are preferably configured such that h1 is slightly larger than or substantially the same dimension as h2, and is intermediate fit of the degree of press-fitting to light press-fitting.

The piston 2 is made of resin and is divided into two pieces in the axial direction by injection molding. is formed in The material used as the resin is not particularly limited, but PP (polypropylene), PPS (polyphenylene sulfide), PA (polyamide), PEI (polyetherimide), PVDF (polyvinylidene fluoride), etc. can be used. These materials can also be used for parts other than the piston.

Between the circumferential projections 2a, a restricting portion 2b is formed to restrict the movement of the sliding body 20 in the circumferential direction when the flat end portion 20c of the sliding body 20 abuts thereon. Further, a through hole 2c through which the stem is inserted is formed in the central portion of the piston 20, and an annular groove 2d in which a spring as the elastic member 5 is placed is formed on one surface. The piston 2 has a small-diameter portion 2e connected to the circumferential projection 2a and the fixed portion 2b, and the small-diameter portion 2e is provided with a seal member 21 that is in sliding contact with the cylinder 30 of the actuator cap 3 and presses the cylinder chamber. side and the working fluid supply side to prevent the working fluid from leaking from the working fluid supply side 33 to the pressing member arrangement side.

Although the slide body 20 is divided into six in this embodiment, the number of divisions is not particularly limited as long as it is divided into two or more. Although the material for the sliding body 20 is not particularly limited, it is preferable to use POM (polyacetal), which has high sliding properties.

In this embodiment, the actuator cap 3 is also made of resin by injection molding, and as shown in the drawing, it has a bowl-like shape and has a cylinder 30 on its inner peripheral surface. The cylinder 30 can ensure the cylindricity of the cylinder only by injection molding without any additional work.

The actuator cap 3 is formed with a working fluid supply port 30A for supplying working fluid for moving the piston 2 into the cylinder 30 against the pressing force of the pressing member 5 . A working fluid discharge port 30B is also formed for discharging the fluid (air) on the pressing member arrangement side to the outside.

A cap 32 is disposed in the through hole 3a formed in the top surface of the actuator cap 3, with which the tip of the shaft portion 40 is slidably contacted and which isolates the inside and the outside of the cylinder. If the valve V to which the actuator 1 is attached is of the normally closed type, the through hole through which the tip of the shaft portion 40 of the stem 4 penetrates is sufficient. In the case of the normally open type, the space on the top side serves as the working fluid supply side, so a cap 32 is provided to isolate the inside from the outside. When arranged in a normally open type valve V, the working fluid discharge port 30B functions to supply the working fluid, and the working fluid supply port 30A functions as the working fluid discharge port.

The valve body 6 is composed of a resin diaphragm 60 and a hard diaphragm retainer 61. From the viewpoint of suppressing early wear of the diaphragm 60, a soft body 62 is disposed between the diaphragm 60 and the diaphragm retainer. there is

The stem 4 is composed of a shaft portion 40 , a large diameter portion 41 and an engaging portion 42 . The engaging portion 42 is formed continuously through the tip of the large diameter portion 41 and the annular stepped portion 42a. The shaft portion 40 is fitted into the through hole 2 c of the piston 2 , and the annular end surface of the large diameter portion 41 abuts against the piston 2 . 2 is fixed.

The stem 4 and the piston 2 are joined by engaging the engaging portion 42 of the stem 4 with the diaphragm retainer 61 of the valve body 6, inserting the stem 4 into the stem insertion opening 83 of the bonnet 8, and This is performed while the diameter portion 41 is in sliding contact with a sealing member (for example, an O-ring) 80a of the stem insertion port 80. As shown in FIG. The stem 4 can also be divided into two in the direction perpendicular to the shaft and made of resin by injection molding. The engaging portion 42 of the stem 4 and the valve body 6 may be engaged after the actuator 1 is assembled.

The pressing means 5 may be a spring, a disk spring, or the like, but is not particularly limited, but a spring is used in this embodiment. Although only one spring may be provided as shown in the figure, a plurality of springs having different diameters may be provided.

The bonnet 8 is composed of a cylindrical main body 80 , a first flange 81 connected to the actuator cap 3 at one end, and a second flange 82 connected to the body 7 at the other end. The opening of the actuator cap 3 is fitted to the annular protrusion 81a of the first flange 81 provided with a seal member for maintaining airtightness between the actuator cap 3 and the bonnet 8 by screwing means such as bolts and screws. It is fixed with the actuator cap 3 . The end surface of the second flange 82 is formed with an annular groove into which the annular engaging portion of the soft body 62 is fitted, and the end surface other than the groove portion sandwiches the flange portion of the diaphragm 61 with the body 7 . The second flange 82 is also fixed to the body 7 by screwing means such as bolts and screws.

In the upper structure, a plurality of sliding bodies 20 are interposed between the piston 2 and the cylinder 30 to keep the axial center of the piston 2 and to effectively prevent the cylinder 30 from being worn or damaged.

INDUSTRIAL APPLICABILITY The actuator according to the present invention can be suitably used as an actuator that needs to use a large-diameter piston, and can be suitably used, for example, as an actuator for opening and closing valves for piping through which a large amount of fluid flows.

Reference Signs List 1 Actuator 2 Piston 2a Circular projection 20 Slider 20a Groove 21 Sealing member 3 Actuator cap 30 Cylinder

30A Working fluid supply port 4 Stem 40 Tapered outer peripheral surface 5 Pressing member 6 Valve body

Claims (3)

An actuator that operates a valve that is disposed in a body that has a flow path and a valve seat, and that includes a valve body that contacts and separates from the valve seat and blocks communication of a fluid flowing through the flow path,
an actuator cap with a cylinder inside;
a piston in sliding contact with the cylinder via a sliding body;
a stem connected to the piston and joined to the valve body at its tip;
an elastic member that presses and biases the piston in one direction;
a working fluid supply port for supplying working fluid in a direction against the pressing force of the elastic member, wherein a circumferential projection is formed on the outer peripheral surface of the piston,
The actuator includes a plurality of grooves on the inner surface of the sliding body that engage with the circumferential projection, and a plurality of the sliding bodies arranged in the circumferential direction of the outer peripheral surface of the piston. 2. The actuator according to claim 1, wherein the piston is made of resin and is divided into two parts in the axial direction by injection molding. 3. The actuator according to claim 2, wherein said actuator cap and stem are made of resin.

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