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EP-4737773-A1 - SPOOL-TYPE SWITCHING VALVE

EP4737773A1EP 4737773 A1EP4737773 A1EP 4737773A1EP-4737773-A1

Abstract

[Object] The present invention provides a spool-type switching valve in which a piston and a spool valve can be connected efficiently. [Solution] The spool-type switching valve has a spool hole 25 elongated along an axial line L and has first and second piston chambers 32 positioned at respective opposite ends of the spool hole 25. The spool hole accommodates first and second spool valves 11b, and these piston chambers accommodate first and second pistons 33. First and second coupling portions 70b are disposed between a valve end surface 34 formed at an end of the spool valve and a piston end surface 33a of the piston that opposes the valve end surface 34. Each of the coupling portions has a projection 72 projecting from the valve end surface and a wall 36 projecting from the piston end surface. The coupling portion has an insertion recess 77 inside the wall 36. An engagement groove 73 is formed in the projection. The wall has a cutout groove that is cut out in the axial direction. The wall has a leg portion disposed inside the cutout groove and also has an engagement hook 47 formed at an end portion of the leg portion. In the state of the projection being inserted in the insertion recess, the engagement hook engages the engagement groove, and the spool valve and the piston are thereby connected together.

Inventors

  • MURAKAMI, TAKASHI

Assignees

  • SMC Corporation

Dates

Publication Date
20260506
Application Date
20240620

Claims (8)

  1. A spool-type switching valve including a body having a spool hole that has an axis and is elongated in an axial direction and having a piston chamber at an end of the spool hole in the axial direction, the spool-type switching valve also including a spool valve slidably accommodated in the spool hole and a piston slidably accommodated in the piston chamber, the body having ports for air inlet, air discharge, and output, the spool-type switching valve being configured to selectively switch states of communication among the ports by supplying and discharging pilot air to the piston chamber and thereby driving the piston together with the spool valve, the spool-type switching valve comprising: a coupling portion being disposed between a valve end surface of the spool valve and a piston end surface of the piston, the valve end surface facing the piston chamber in the axial direction, the piston end surface opposing the valve end surface, the coupling portion connecting the valve end surface and the piston end surface, wherein the coupling portion includes a projection projecting from the valve end surface of the spool valve and an insertion recess formed at the piston end surface of the piston, the projection being inserted in the insertion recess, the projection has an engagement groove formed so as to extend circumferentially about the axis, an annular wall projects from the piston end surface, and the insertion recess is positioned inside the annular wall, the wall has a cutout groove formed through the wall in the axial direction and also has an engagement portion disposed in the cutout groove, the engagement portion engaging the engagement groove, the engagement portion includes a leg portion elongated in the axial direction and having a base portion fixed to the piston end surface and an engagement hook formed at an end portion of the leg portion so as to project inward in a radial direction with the axis being a center, the engagement hook engages the engagement groove while the projection is inserted in the insertion recess, and the leg portion is elastically deformable outward in the radial direction with the axis being the center.
  2. The spool-type switching valve according to Claim 1, wherein the engagement hook has a portion projecting inward in the radial direction and an inclined surface formed on the portion, and the inclined surface inclines outward in the radial direction as a distance from the valve end surface of the spool valve becomes smaller.
  3. The spool-type switching valve according to Claim 1, wherein a recess is formed at the piston end surface at a position where the leg portion is disposed, and a base portion of the leg portion is disposed at a bottom of the recess.
  4. The spool-type switching valve according to Claim 1, wherein a stopper with which an end portion of the projection comes into contact is formed at a bottom of the insertion recess, and in a state in which the end portion of the projection is in contact with the stopper, a gap is formed between the valve end surface of the spool valve and an end of the engagement portion, the end opposing the valve end surface.
  5. The spool-type switching valve according to Claim 4, wherein the contact between the projection of the spool valve and the stopper of the piston is achieved by contact between flat end surfaces that orthogonally intersect the axis.
  6. The spool-type switching valve according to Claim 4, wherein the end of the engagement portion and a top surface of the wall that opposes the valve end surface are positioned on a same plane that orthogonally intersects the axial direction.
  7. The spool-type switching valve according to Claim 1, wherein a plurality of the cutout grooves is formed in the wall at an equiangular distance about the axis.
  8. The spool-type switching valve according to any one of Claims 1 to 7, wherein the piston chambers are formed at respective opposite ends of the spool hole in the axial direction, the pistons are accommodated in respective piston chambers, two of the spool valves are accommodated in the spool hole, a length of the spool hole in the axial direction is greater than a sum of axial lengths of the two spool valves, and the coupling portion connects each of the two spool valves accommodated in the spool hole to an adjacent one of the pistons.

Description

Technical Field The present invention relates to a spool-type switching valve in which a piston drives a spool valve that is slidably accommodated in a spool hole. Background Art PTL 1 discloses an example of a known spool-type switching valve in which a piston drives a spool valve that is slidably accommodated in a spool hole. In this spool-type switching valve, the piston and the spool valve are provided as separate members and are connected together by a coupling portion. The coupling portion is formed by engaging an engagement portion provided at the spool valve with a counterpart engagement portion provided at the piston. As illustrated in Fig. 12, the known spool-type switching valve uses a coupling portion 112 for connecting a spool valve 110 and a piston 111. The coupling portion 112 is structured such that an engagement portion 113 and a counterpart engagement portion 114 engage each other by moving the spool valve 110 and the piston 111 closer to each other in a direction orthogonally intersecting the axes thereof. In the known structure of the coupling portion, however, the process of connecting the spool valve 110 and the piston 111 tends to become complicated and is not always efficient because it is necessary to move the spool valve 110 and the piston 111 closer to each other in the direction orthogonally intersecting the axes thereof as described above. Citation List Patent Literature PTL 1: Japanese Unexamined Patent Application Publication No. 2013-24345 Summary of Invention Technical Problem Accordingly, the technical problem of the present invention is to provide a spool-type switching valve in which the piston and the spool valve are provided as separate members and the piston and the spool valve can be connected more efficiently. Solution to Problem The present invention provides a spool-type switching valve that includes a body, a spool valve, and a piston. The body has a spool hole that has an axis and is elongated in an axial direction, and the body also has a piston chamber at an end of the spool hole in the axial direction. The spool valve is slidably accommodated in the spool hole, and the piston is slidably accommodated in the piston chamber. The body has ports for air inlet, air discharge, and output. The spool-type switching valve is configured to selectively switch states of communication among the ports by supplying and discharging pilot air to the piston chamber and thereby driving the piston together with the spool valve. The spool-type switching valve further includes a coupling portion that is disposed between a valve end surface of the spool valve and a piston end surface of the piston. The valve end surface faces the piston chamber in the axial direction, and the piston end surface opposes the valve end surface. The coupling portion connects the valve end surface and the piston end surface. The coupling portion includes a projection projecting from the valve end surface of the spool valve and an insertion recess formed at the piston end surface of the piston, the projection being inserted in the insertion recess. The projection has an engagement groove formed so as to extend circumferentially about the axis. An annular wall projects from the piston end surface, and the insertion recess is positioned inside the annular wall. The wall has a cutout groove formed through the wall in the axial direction and also has an engagement portion disposed in the cutout groove, the engagement portion engaging the engagement groove. The engagement portion includes a leg portion elongated in the axial direction and having a base portion fixed to the piston end surface and also includes an engagement hook formed at an end portion of the leg portion so as to project inward in a radial direction with the axis being a center. The engagement hook engages the engagement groove while the projection is inserted in the insertion recess. The leg portion is elastically deformable outward in the radial direction with the axis being the center. In this case, the engagement hook preferably has a portion projecting inward in the radial direction and an inclined surface formed on the portion, and the inclined surface preferably inclines outward in the radial direction as a distance from the valve end surface of the spool valve becomes smaller. In addition, a recess is preferably formed at the piston end surface at a position where the leg portion is disposed, and a base portion of the leg portion is preferably disposed at a bottom of the recess. Moreover, a stopper with which an end portion of the projection comes into contact is preferably formed at a bottom of the insertion recess. In a state in which the end portion of the projection is in contact with the stopper, a gap is preferably formed between the valve end surface of the spool valve and an end of the engagement portion, the end opposing the valve end surface. The contact between the projection of the spool valve and the stopper of the piston