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DE-112023006747-T5 - Switching valve and hydraulic shock absorber with the switching valve

DE112023006747T5DE 112023006747 T5DE112023006747 T5DE 112023006747T5DE-112023006747-T5

Abstract

A switching valve (10) comprises a valve seat (54), a valve body (60), a through-flow section (73), and a restrictor (71a). The valve seat (54) has a valve seat surface (54b) formed on a circumferential edge of a valve opening (54a). The valve body (60) is a resin-molded part that moves in one direction along an axis (CL) of the valve seat surface (54b). The valve body (60) has a sealing part (61) with a curved sealing surface (61a) that seals the valve seat surface (54b), and an extension part (62) that extends from the sealing part (61) to a side opposite the sealing surface (61a). A mark (63) created during the injection molding of the valve body (60) remains on the extension part (62). The passage section (73) has an oil passage (73a) which forms part of a flow path (Fp) when the sealing surface (61a) is separated from the valve seat surface (54b). The restricting part (71a) limits the position of the extension part (62) to maintain an open and closed position of the sealing surface (61a) relative to the valve seat surface (54b).

Inventors

  • Yosuke Murakami
  • Yosuke FUJIKAWA
  • Naoya KUROIWA
  • Daisuke Michiura
  • Masataka Fujita

Assignees

  • ASTEMO, LTD.

Dates

Publication Date
20260513
Application Date
20230801

Claims (10)

  1. Switching valve (10, 200), comprising: a valve seat (54) having a valve opening (54a) configured to communicate with a flow path (Fp) through which oil flows, and a valve seat surface (54b) formed on a circumferential edge of the valve opening (54a); a valve body (60, 260), which is an element made of a resin molded product and which moves in one direction along an axis (CL) of the valve seat surface (54b) to come into contact with and separate from the valve seat surface (54b) in order to open and close the valve opening (54a), wherein the valve body (60, 260) comprises: a sealing part (61) having a sealing surface (61a) in a curved shape which bears against the valve seat surface (54b) to seal the valve opening (54a); and an extension part (62, 264) extending from the sealing part (61) to a side opposite the sealing surface (61a) and formed integrally with the sealing part (61), wherein a marking (63, 265) created during the injection molding of the valve body (60, 260) remains on the extension part (62, 264); a passage section (73, 273) configured to form part of the flow path (Fp) when the sealing surface (61a) of the valve body (60, 260) is separated from the valve seat surface (54b); and a limiting part (71a; 263, 282) designed to limit a position of the extension part (62, 264) in order to maintain an opening and closing position of the sealing surface (61a) relative to the valve seat surface (54b).
  2. Switching valve (10, 200) according to Claim 1 , further comprising: a retaining element (70) designed to hold the extension part (62), wherein the through section (73) and the limiting part (71a) are formed on the retaining element (70).
  3. Switching valve (10, 200) according to Claim 2 , wherein the passage section (73) is provided by an oil passage (73a) formed on an outer circumferential surface (70c) of the retaining element (70), and the passage section (73) extends in the axial direction (CL) of the valve seat surface (54b).
  4. Switching valve (10, 200) according to Claim 3 , wherein an oil passage flow path (75) is formed between the oil passage (73a) and the valve seat (54) over an entire circumference around at least one section of the outer circumferential surface (70c) of the retaining element (70), in which the section holds the extension part (62).
  5. Switching valve (10, 200) according to Claim 2 , wherein the retaining element (70) is provided with a spring receiving recess (72) which receives an end section of a helical compression spring (82) on an end surface opposite to a section which holds the extension part (62), and wherein a bottom surface (72a) of the spring receiving recess (72) is biased by the helical compression spring (82) in a direction in which the sealing surface (61a) of the valve body abuts the valve seat surface (54b).
  6. Switching valve (10, 200) according to Claim 1 , wherein the sealing part (61) has a hemispherical shape; and wherein the extension part (62) connects to a bottom section (61b) of the sealing part (61) and is designed as a column-shaped section with a diameter (Bd) corresponding to the diameter of the bottom section (61b).
  7. Switching valve (10, 200) according to Claim 2 , wherein the valve body (60) is the resin molded part made from a flexible resin, wherein the retaining element (70) has a retaining bore (71) which holds the extension part (62), wherein the extension part (62) is held by press fit in the retaining bore (71).
  8. Switching valve (200) according to Claim 1 , wherein the extension part (264) has a tapered large-diameter section (262) with a diameter that increases from the bottom section (61b) of the sealing part (61) to a side opposite the sealing surface (61a), wherein the through-pass section (273) is formed on an outer circumferential surface (262c) of the large-diameter section (262) and the through-pass section (273) extends in the axial direction (CL) of the valve seat surface (54b), and wherein the switching valve (200) further comprises a retaining element (250) configured to hold an outer circumferential surface of the extension part (264) on a part having a largest outer diameter of the large-diameter section (262).
  9. Switching valve (10, 200) according to Claim 8 , wherein the extension part (264) has a column-shaped small diameter section (263) extending from a base surface (262b) of the large diameter section (262) to a side opposite the base surface (61b) of the sealing part and having a smaller diameter than the base surface (262b) of the large diameter section, wherein the base surface (262b) of the large diameter the small diameter section (262) is pre-tensioned by the helical compression spring (282) in a direction in which the sealing surface (61a) of the valve body rests against the valve seat surface (54b), wherein the small diameter section (263) is fitted into a coil of the helical compression spring (282), and wherein the limiting part is formed from the small diameter section (263) and the helical compression spring (282).
  10. Hydraulic shock absorber comprising the switching valve (10, 200) according to Claim 1 .

Description

TECHNICAL AREA The present invention relates to a technique for improving a switching valve and a hydraulic shock absorber that includes the switching valve. STATE OF THE ART Among switching valves, there is a so-called ball switching valve, which uses a spherical valve body that moves in one direction along the axis of a valve seat surface to make contact with and separate from the valve seat surface, thus opening and closing a valve orifice. This type of ball switching valve is frequently used, for example, in a check valve, a relief valve, and a hydraulic shock absorber. This type of ball switching valve is known, for example, from patent literature 1. The ball-type switching valve, known from patent literature 1, is provided in a hydraulic shock absorber (an electrically controlled damper) and comprises a valve seat with a tapered valve seat surface, a spherical valve body capable of contacting and separating from the valve seat surface, and a helical compression spring that presses the valve body against the valve seat surface. The valve body moves in one direction along an axis of the valve seat surface to open and close the valve orifice. The valve orifice communicates with a flow path through which oil flows. The preload force of the helical compression spring is transmitted to the valve body via the pressure element. When the valve body is pushed by the pushrod and separated from the valve seat surface, the valve orifice of the ball-type switching valve opens, and the oil flows through the flow path. The spherical valve body exhibits high contact pressure with the valve seat surface and thus possesses good sealing properties. CITATION LIST PATENT LITERATURE Patent literature 1: JP2016-176552A (see 3 and 4 ) SUMMARY OF THE INVENTION TECHNICAL PROBLEM Since the valve body has a spherical shape, the entire spherical surface of the switching valve known from patent literature 1 can serve as a sealing surface. Therefore, the area where the valve body contacts the valve seat is not constant. The valve body can, for example, be formed from a resin molded part to reduce costs. During injection molding of the valve body, a marking (a mold track), such as a parting line or a gate, may occur. Regardless of the area where the valve body contacts the valve seat, it is necessary to polish the marking to avoid impairing the sealing performance of the valve body. If the manufacturing process of the valve body includes a polishing process, this is detrimental in terms of increasing the productivity of the valve body and reducing the manufacturing costs of the switching valve. One object of the present invention is to provide a technique that is able to reduce the cost of a switching valve which includes a valve body made from a resin molded part, while ensuring sealing performance. SOLUTION TO THE PROBLEM As a result of intensive studies, the present inventors focused on the fact that the sealing surface of the valve body, which is the only part in contact with the valve seat surface, can have a curved surface shape. It was then discovered that the position of the valve body can be limited by forming only the sealing surface of the valve body with a curved surface shape and the other section with a non-curved surface shape, thus making the section where the valve body contacts the valve seat surface constant. The present invention was developed based on this finding. The present disclosure provides a switching valve which includes the following: comprising a valve seat, a valve opening designed to communicate with a flow path through which oil flows, and a valve seat surface formed on a circumferential edge of the valve opening; a valve body, which is an element made from a resin molded part, and which extends in one direction along an axis of the vein The valve seat surface moves to come into contact with and separate from the valve seat surface in order to open and close the valve orifice, the valve body comprising: comprising a sealing element comprising a sealing surface in a curved shape that rests against the valve seat surface to seal the valve opening; and an extension part which extends from the sealing part to a side opposite the sealing surface and is formed integrally with the sealing part, wherein a marking created during the injection molding of the valve body remains on the extension part; comprising a passage section, an oil passage designed to form part of the flow path when the sealing surface of the valve body is separated from the valve seat surface; and a restricting part designed to limit the position of the extension part in order to maintain an opening and closing position of the sealing surface relative to the valve seat surface. ADVANTAGEOUS EFFECTS OF THE INVENTION According to the present disclosure, it is possible to provide a technique that is able to reduce the cost of the switching valve, which includes the valve body manufactured from a resin molded part, while ensuring sealing perf