JP4787025B2 - Endoscope switching valve - Google Patents

Description

  The present invention relates to an endoscope duct switching valve.

  In general, a pipe switching valve provided in an operation section of an endoscope for switching an air supply / water supply pipe or a suction pipe is a cylinder having a circular cross-sectional shape to which a plurality of fluid pipes are connected. The piston is configured so as to be movable back and forth in the axial direction, and the pipe line is sealed by an O-ring or the like mounted in a circumferential groove formed in the piston.

  However, in an endoscope (for example, an ultrasonic endoscope) in which a balloon that can be expanded and contracted is attached to the distal end of the insertion portion, a switching function for a fluid conduit communicating with the balloon is added. If sealing is performed with an O-ring, the length of the pipe switching valve becomes too long.

Therefore, in such an endoscope conduit switching valve, a contact plug made of an elastic member for independently closing only the opening of the fluid conduit communicating with the balloon into the cylinder is provided on the cylinder. It is attached to the outer peripheral surface portion of the piston in a state of being crushed and elastically deformed by the inner peripheral surface (for example, Patent Document 1).
JP 2005-58547 A

  FIG. 13 is an enlarged view of a contact plug 95 portion of a conventional line switching valve of an endoscope, and a balloon suction pipe 91 communicating with a balloon (not shown) is connected to the outer surface of a cylinder 92. An opening 91 a of the balloon suction conduit 91 is formed on the inner peripheral surface of the cylinder 92.

  And, there is elasticity for closing only the opening 91a of the balloon suction conduit 91 in the bottomed hole 94 formed in the outer peripheral surface of the piston 93 which is disposed in the cylinder 92 so as to be movable back and forth in the axial direction. A contact plug 95 made of a member is arranged in an elastically deformed state by being crushed by the inner peripheral surface of the cylinder 92. FIG. 13 shows the shape before the contact plug 95 is crushed.

  In the endoscope line switching valve having such a configuration, the outer end surface of the contact plug 95 is rubbed against the inner peripheral surface of the cylinder 92 every time the piston 93 is moved back and forth in the axial direction for switching the line. In particular, as shown in FIG. 14, when the end of the contact plug 95 is caught by the edge of the opening 91a of the balloon suction conduit 91, the contact plug 95 is damaged early and the fluid is There was a case where leakage occurred. FIG. 14 shows an actual shape in which the contact plug 95 is elastically deformed.

  Therefore, the present invention provides an endoscope capable of obtaining excellent durability in which a contact plug for independently closing only an opening formed on an inner peripheral surface of a cylinder is not damaged even when a pipeline switching operation is repeated. An object of the present invention is to provide a pipeline switching valve.

  In order to achieve the above-mentioned object, an endoscope pipeline switching valve according to the present invention includes a plurality of fluid pipelines in an inner peripheral surface portion of a cylinder having a circular cross-sectional shape to which a plurality of fluid pipelines are connected. There is at least one opening, and there is elasticity to block only the opening on the inner peripheral surface of the cylinder alone in the bottomed hole formed on the outer peripheral surface of the piston arranged in the cylinder so as to be able to advance and retract in the axial direction. In an endoscope conduit switching valve in which a contact plug made of a member is crushed by an inner peripheral surface of a cylinder and elastically deformed, the outer end surface of the contact plug is made larger than the radius of the inner peripheral surface of the cylinder. It is formed in a spherical shape with a small radius of curvature.

  It should be noted that the outer end surface of the contact plug may be in a position recessed in the bottomed hole and recessed from the outer peripheral surface of the piston, at both end positions of the bottomed hole in the axial direction of the piston. And also in the position of the both ends of the bottomed hole in the circumferential direction of the piston, the outer end surface of the contact plug may be in a position recessed in the bottomed hole and recessed from the outer peripheral surface of the piston.

  Further, an inflatable / deflatable balloon may be attached to the distal end of the insertion portion of the endoscope, and the opening closed by the contact plug may be an opening of a fluid conduit communicating with the inside of the balloon.

  In order to block only the opening formed on the inner peripheral surface of the cylinder alone, the outer end surface of the contact plug disposed in the bottomed hole on the outer peripheral surface of the piston is a spherical surface having a radius of curvature smaller than the radius of the inner peripheral surface of the cylinder. By forming in a shape, even if the pipe switching operation is repeated, the contact plug is not caught by the edge of the opening and damaged, and excellent durability can be obtained.

  The outer periphery of a piston in which at least one of the plurality of fluid conduits opens on the inner peripheral surface of a cylinder having a circular cross-sectional shape to which a plurality of fluid conduits are connected, and is movable in the axial direction in the cylinder. In the bottomed hole formed in the surface, the contact plug made of a resilient member for closing only the opening of the inner peripheral surface of the cylinder alone is crushed by the inner peripheral surface of the cylinder and elastically deformed In the endoscope line switching valve disposed in the outer surface of the endoscope, the outer end surface of the contact plug is formed into a spherical shape having a radius of curvature smaller than the radius of the inner peripheral surface of the cylinder.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 2 shows an ultrasonic endoscope to which the present invention is applied. An operation unit 2 is connected to a proximal end of a flexible insertion unit 1, and an ultrasonic wave is formed around the axis at the distal end of the insertion unit 1. For example, an ultrasonic probe 3 for radial scanning for transmitting and receiving signals is disposed, and an optical observation window 4 for optically observing the front is disposed on the distal end surface.

  In addition, the distal end portion of the insertion portion 1 is inflated and contracted by deaerated water or the like so that there is no air layer with poor ultrasonic signal transmission between the ultrasonic probe 3 and the test portion. 5 is attached to surround the ultrasonic probe 3.

  A forceps channel 6 for inserting and removing forceps, an injection tool, and the like is inserted through the entire length in the insertion portion 1, and a channel suction port 6 a that is a distal end opening of the forceps channel 6 is located outside the balloon 5. 1 is disposed on the front end surface.

  The forceps insertion port 6b is disposed in the vicinity of the connecting portion between the insertion portion 1 and the operation portion 2, and a channel suction conduit 7 connected to the forceps channel 6 in the vicinity of the proximal end thereof is provided in the operation portion. 2 is connected to a suction operation valve 10 arranged in the upper half of the two.

  A balloon suction conduit 8 and the like for sucking deaerated water filled in the balloon 5 are also inserted from the insertion portion 1 into the operation portion 2, and is a distal end opening of the balloon suction conduit 8. The balloon suction port 8 a is opened inside the balloon 5 at the distal end of the insertion portion 1, and the proximal end of the balloon suction conduit 8 is connected to the suction operation valve 10 in the operation portion 2. Reference numeral 9 denotes a suction source pipe line that connects the suction operation valve 10 and a suction source (not shown) in communication.

  1 and 3 are longitudinal sectional views showing a standby state of the suction operation valve 10, and FIG. 1 is a cross-sectional view taken along the line II in FIG. 4, showing a pipeline switching state in the standby state. FIG. 4 is a cross-sectional view taken along the line III-III in FIG. 4 and includes a rotation stop protrusion 25 and an engagement groove 26 for restricting the suction line switching piston 14 from rotating around the axis with respect to the cylinder 11. It is a waste.

  As shown in FIG. 1 and FIG. 3, the cylinder 11 disposed in the operation unit 2 is fixed to the operation unit 2 by a fixing nut 12 so as to open outward. Reference numeral 13 denotes an O-ring for sealing. 1 and 4 show a state before being crushed by a kind of seal member that is mounted in a crushed state with elasticity.

  The cylinder 11 formed in a cylindrical shape with a bottom is formed so that the inner diameter of the inner half near the back is narrower than the inner diameter of the half near the mouth, and the proximal end of the channel suction line 7 is such a cylinder 11. An opening is connected to the bottom surface portion of the.

  Further, as shown in FIG. 4 showing the IV-IV cross section in FIG. 3, the balloon suction line 8 and the suction source line 9 are shifted in the direction around the axis, and the suction source line 9 is It is connected to the side surface of the portion near the mouth of the cylinder 11 in a positional relationship on the back side (downward in FIG. 3) from the balloon suction conduit 8, and the proximal end opening 8b (opening) of the balloon suction conduit 8 and the suction source Connection openings 9 a of the pipe lines 9 are respectively opened on the inner peripheral surface of the cylinder 11.

  As shown in FIGS. 1 and 3, the piston fitted into the cylinder 11 so as to be movable back and forth in the axial direction is a cylindrical suction pipe switching piston that is inscribed in the cylinder 11 so as to be movable back and forth in the axial direction. 14 and an outside air suction switching piston 15 that is slidably inscribed in the axial direction with respect to the suction pipe switching piston 14 are arranged coaxially. The outer diameter of the suction pipe switching piston 14 is smaller than the inner diameter.

  The outer diameter of each of the suction line switching piston 14 and the outside air suction switching piston 15 is such that only the outside air suction switching piston 15 is inscribed in the inner peripheral surface of the inner half of the cylinder 11 (small diameter portion). The suction pipe switching piston 14 is inscribed in the inner peripheral surface of the half portion (large diameter portion) near the mouth of the cylinder 11.

  The heads of the suction line switching piston 14 and the outside air suction switching piston 15 protrude from the mouth of the cylinder 11 that opens to the outer surface of the operation unit 2. The operation button 16 is attached via one spring receiving member 18 and a connecting shaft 150 also shown in the exploded perspective view of FIG.

  As shown in FIG. 6, a second spring receiving member 19 formed in a flange shape is screwed to the head portion of the suction pipe switching piston 14, and the first spring receiving member A direction in which the outside air suction switching piston 15 jumps outward from the suction line switching piston 14 by the first compression coil spring 21 mounted between the first spring receiving member 18 and the second spring receiving member 19 (FIGS. 1 and 3 is upwardly biased.

  However, the step formed in the middle of the inner surface of the suction line switching piston 14 and the step formed in the middle of the outer surface of the outside air suction switching piston 15 come into contact with each other, so that the outside air suction switching piston 15 is From the state shown in FIG. 1 and FIG. 3, it is restricted so that it does not protrude relatively outward from the suction line switching piston 14.

  Further, the first cover cylinder 17 that covers the first compression coil spring 21 so as not to be seen from the outside is attached in a state of being pressed against the second spring receiving member 19 by the first compression coil spring 21. ing.

  Reference numeral 22 denotes a second compression coil spring which is set to a spring constant several times larger than that of the first compression coil spring 21, and is arranged in a series relationship with the first compression coil spring 21, and the second The spring receiving member 19 is urged outward.

  The piston retaining ring 20A that receives the proximal end side of the second compression coil spring 22 also serves as a stopper that prevents the suction line switching piston 14 from coming out of the cylinder 11 beyond a predetermined state. It also has a cover function for making the compression coil spring 22 invisible from the outside.

  Further, the inner claw portion of the lower end portion of the locking ring 20B made of a resilient plastic material lined integrally with the piston locking ring 20A is hooked and engaged with the outer peripheral flange portion of the fixing nut 12, thereby sucking it. A unit including a pipe switching piston 14, an outside air suction switching piston 15 and an operation button 16 is fixed to the cylinder 11.

  Therefore, when the engagement ring 20B is elastically deformed to disengage the fixed nut 12, the suction line switching piston 14 and the outside air suction switching piston 15 are pulled out from the cylinder 11 together with the operation button 16 and the like. Can do.

  Further, the suction pipe switching piston 14 and the outside air suction switching piston 15 are symmetrical with respect to the outer surface of the outside air suction switching piston 15 as shown in FIG. 7 illustrating the VII-VII cross section in FIG. The flat surface portion 15a scraped flat at the position and the flat surface portion 14a formed on the inner surface of the suction pipe switching piston 14 so as to loosely sandwich the flat surface portion 15a are arranged so as to face each other. The suction line switching piston 14 and the outside air suction switching piston 15 are also relatively movable in the axial direction, but cannot rotate around the axial line.

  As shown in FIG. 6, the suction pipe switching piston 14 has an intermediate portion between the outer peripheral surfaces of the suction pipe switching piston 14 so as to be in sliding contact with the inner peripheral surface of the portion near the mouth of the cylinder 11. An outer position side hole 28 and an inner position side hole 29 are formed on both sides of the sealing O ring 27 attached to the portion so as to penetrate the side walls.

  Further, the cylinder 11 is configured such that only the proximal end opening 8b of the balloon suction conduit 8 is closed on the outer peripheral surface in the vicinity of the back end of the suction conduit switching piston 14 fitted to the inner peripheral surface of the cylinder 11 alone. An abutment plug 34 made of a resilient rubber material or the like that is in sliding contact with the inner peripheral surface of the ball is provided in the center of a circular bottomed hole 33 formed at a position facing the proximal end opening 8b of the balloon suction pipe 8. The neighborhood is fitted in a slightly protruding state.

  The abutment plug 34 is shown in an enlarged vertical sectional view in FIG. 8, a plan sectional view in FIG. 4 and a perspective view in FIG. It is larger than the base end opening 8b of the suction pipe 8 and has a disk shape or a columnar shape having a size of about a quarter of the diameter of the suction pipe switching piston 14.

  However, the outer end surface of the contact plug 34 is formed in a spherical shape, and its central portion slightly protrudes from the outer surface of the suction pipe switching piston 14 and is pushed by the inner peripheral surface of the cylinder 11. It is elastically deformed into a crushed state, and the base end opening 8b of the balloon suction conduit 8 is closed. 4 and 8 show a shape in which the contact plug 34 is not crushed.

  The outer end surface of the contact plug 34 directed to the inner peripheral surface of the cylinder 11 is formed in a spherical shape having a curvature radius smaller than the radius of the inner peripheral surface of the cylinder 11, and its peripheral portion is in the bottomed hole 33. It is in a position that is submerged and slightly recessed from the outer peripheral surface of the suction pipe switching piston 14.

  That is, as shown in FIG. 8, the outer end surfaces of the contact plugs 34 are dived into the bottomed hole 33 at both end positions of the bottomed hole 33 in the axial direction of the suction line switching piston 14 and sucked. In the position slightly recessed from the outer peripheral surface of the pipe switching piston 14, and as shown in FIG. 4, at both end positions of the bottomed hole 33 in the circumferential direction of the suction pipe switching piston 14, The outer end surface of the contact plug 34 is located in the bottomed hole 33 and is slightly recessed from the outer peripheral surface of the suction line switching piston 14.

  As a result, when the suction line switching piston 14 removed from the cylinder 11 is assembled to the cylinder 11 or the like, the abutment plug 34 is not caught in the mouth opening of the cylinder 11, and the suction line switching piston 14 is 11, the contact plug 34 is not caught by the edge of the proximal end opening 8 b of the balloon suction pipe 8.

  Along with the contact plug 34, the suction passage 30 serving as a fluid passage partially scrapes the outer surface near the back end of the suction pipe switching piston 14 as shown in FIGS. The suction path 30 is formed at a position facing the connection opening 9a of the suction source pipe line 9 and a position 180 [deg.] Symmetrical to the position.

  However, as shown in FIG. 4, at the back side position A symmetrical with respect to the position where the contact plug 34 of the suction pipe switching piston 14 is attached, the outer peripheral surface of the suction pipe switching piston 14 Is in perfect contact with the inner peripheral surface of the cylinder 11 without being cut out by the suction passage 30 or the like.

  Therefore, although the suction line switching piston 14 is strongly urged in the direction of the back side A by the repulsive force generated from the contact plug 34 crushed between the suction line switching piston 14 and the cylinder 11. As a result, the axial line position of the suction line switching piston 14 is not shifted, and the suction line switching piston 14 smoothly moves back and forth in the axial direction.

  As shown in FIG. 1, the outside air suction switching piston 15 is formed with an L-shaped channel suction communication hole 31 that opens to the side surface and the back end surface. 31a is a back side opening, and 31b is a side opening.

  As shown in FIG. 5, the outer air suction switching piston 15 has cylinders in the vicinity of the rear end and on both sides of the side opening 31 b of the channel suction communication hole 31. A sealing O-ring 35 slidably in contact with the inner peripheral surface of 11 is mounted. An O-ring 36 is also mounted near the base of the connecting shaft 150.

  Further, as shown in FIG. 3, the rotation prevention protrusion 25 for restricting the suction pipe switching piston 14 from rotating about the axis with respect to the cylinder 11 is provided at the outermost position of the suction pipe switching piston 14. It protrudes from the outer peripheral surface in the vicinity of the tip position (that is, the position that is most deep in the back of the cylinder 11).

  An engagement groove 26 that engages with the rotation-stop projection 25 is formed on the inner peripheral surface of the cylinder 11 so as to be straight in the direction parallel to the axis corresponding to the movement range of the rotation-stop projection 25. As a result, the suction line switching piston 14 is movable in the axial direction with respect to the cylinder 11, but cannot rotate around the axial line.

  The rotation stop projection 25 is fixedly embedded in the suction line switching piston 14, and a portion protruding laterally from the outer peripheral surface of the suction line switching piston 14 is formed in a spherical shape. The cross-sectional shape of the engagement groove 26 is formed in an arc shape that allows a certain slight gap to the rotation stop projection 25. Therefore, when the suction line switching piston 14 advances and retracts in the axial direction, the sliding resistance between the engaging groove 26 is small and smoothly advances and retracts even if a rotational force or the like is applied in the axial direction.

  As shown in FIG. 3 and FIG. 4, the rotation stopper protrusion 25 and the engagement groove 26 are arranged with respect to the suction pipe switching piston 14 and the cylinder 11. Slightly close to the mouth and disposed so as not to interfere with the contact plug 34, and the engagement groove 26 does not interfere with the proximal opening 8b of the balloon suction conduit 8, the connection opening 9a of the suction conduit 9, and the like. Has been placed.

  In the endoscope switching valve according to the embodiment having the above-described configuration, the suction pipe switching piston 14 and the outside air suction switching piston 15 are the second in the standby state shown in FIGS. The compression coil springs 22 and the first compression coil springs 21 are pushed up to the maximum extent to project outward.

  Then, after the outside air passes through the outer position side hole 28 and enters the suction pipe switching piston 14, it exits from the inner position side hole 29 to the gap between the suction pipe switching piston 14 and the cylinder 11, and from there. It passes through the suction path 30 and is sucked into the suction source pipe line 9. Suction from the channel suction line 7 and the balloon suction line 8 is blocked by the O-ring 35 and the contact plug 34.

  From this state, the operation button 16 is pushed in with the fingertip, and the operation button is moved to a position where the first compression coil spring 21 is compressed and the second compression coil spring 22 begins to be compressed as shown in FIG. When 16 reaches, a large resistance acts on the finger that operates the operation button 16, and at that time, the side opening 31 b of the channel suction communication hole 31 formed in the outside air suction switching piston 15 is connected to the suction source pipe line 9. It comes to a position facing the opening 9a.

  As a result, the channel suction line 7 and the suction source line 9 communicate with each other through the inside of the cylinder 11 and the channel suction communication hole 31, and sewage or the like in the body is sucked from the channel suction port 6 a at the tip of the insertion portion 1. Sucked into the source.

  In this state, the suction line switching piston 14 is not yet moved, and if the finger is released from the operation button 16 in this state, the original standby state is restored. Therefore, it is possible to perform only the suction operation from the channel suction line 7 while the base end opening 8b of the balloon suction line 8 is completely closed by the contact plug 34.

  Further, as described above, the rotation between the cylinder 11 and the suction line switching piston 14 is stopped around the axis by the engagement of the rotation preventing projection 25 and the engagement groove 26, and the suction line switching piston. 14 and the outside air suction switching piston 15 are prevented from rotating around the axis by the engagement of the flat portions 14a and 15a, so that the side opening 31b of the channel suction communication hole 31 is always accurately and accurately drawn. Since it opposes the connection opening 9 a of the passage 9, even if there is a solid suction material or the like, the suction operation valve 10 is surely sucked and discharged without being clogged in the suction operation valve 10.

  When the operation button 16 is pushed in with further force applied to the fingertip from the state shown in FIG. 9, the rotation stop projection 25 slides to the back side position (downward in the figure) of the engagement groove 26 as shown in FIG. Then, as shown in FIG. 11, the second compression coil spring 22 is also compressed following the first compression coil spring 21, and the suction pipe switching piston 14 together with the outside air suction switching piston 15 is placed in the cylinder 11. It will be in the state pushed into.

  Then, the contact plug 34 moves from the position facing the proximal end opening 8b of the balloon suction pipe 8 to the back side, and at the same time, the side opening 31b of the channel suction communication hole 31 faces the connection opening 9a from the position of the cylinder 11. It is in a state where it is retracted and closed in the back half.

  As a result, only the space between the proximal end opening 8b of the balloon suction line 8 and the connection opening 9a of the suction source line 9 is between the inner peripheral surface of the cylinder 11 and the outer peripheral surface of the suction line switching piston 14. Since the communication is established via the formed space B and the suction path 30, degassed water or the like in the balloon 5 is sucked from the balloon suction port 8 a at the tip of the insertion portion 1 to the suction source and the balloon 5 is contracted. I can do it.

  Then, when the finger is released from the operation button 16, the state returns to the standby state shown in FIGS. 1 and 3 through the suction state from the channel suction line 7 shown in FIG. 34 passes through the proximal end opening 8b of the balloon suction conduit 8.

  However, since the outer end surface of the contact plug 34 is submerged in the bottomed hole 33 at both end positions of the bottomed hole 33 in the axial direction of the cylinder 11, as shown in FIG. However, the contact plug 34 is not damaged even if this operation is repeated.

  Further, since the outer end surface of the contact plug 34 lies in the bottomed hole 33 at both end positions of the bottomed hole 33 in the circumferential direction of the cylinder 11, the contact plug 34 is connected to the inner peripheral surface of the cylinder 11. Therefore, the durability of the contact plug 34 is improved.

  The present invention is not limited to the above-described embodiment. For example, the present invention may be applied to a general endoscope other than an ultrasonic endoscope, and an air / water supply operation valve and other various operation valves. Can be applied to.

It is a longitudinal cross-sectional view (II sectional drawing in FIG. 4) of the standby state in the pipe line switching valve of the endoscope of the Example of this invention. 1 is a side view showing an overall configuration of an ultrasonic endoscope according to an embodiment of the present invention. It is a longitudinal cross-sectional view (III-III sectional drawing in FIG. 4) containing the protrusion for rotation prevention in the standby state in the pipeline switching valve of the endoscope of the Example of this invention. It is IV-IV sectional drawing in FIG. 3 of the pipe line switching valve of the endoscope of the Example of this invention. It is a disassembled perspective view of the external air suction switching piston of the conduit switching valve of the endoscope of the embodiment of the present invention. It is a disassembled perspective view of the suction line switching piston of the pipe line switching valve of the endoscope of the embodiment of the present invention. It is VII-VII sectional drawing in FIG. 1 of the pipe line switching valve of the endoscope of the Example of this invention. It is an expanded longitudinal cross-sectional view of the contact plug part of the pipe line switching valve of the endoscope of the Example of this invention. It is a longitudinal cross-sectional view of the state attracted | sucked from the channel suction conduit in the conduit switching valve of the endoscope of the Example of this invention. It is a longitudinal cross-sectional view including the protrusion for rotation prevention of the state attracted | sucked from the balloon suction conduit in the conduit | pipe switching valve of the endoscope of the Example of this invention. It is a longitudinal cross-sectional view of the state attracted | sucked from the balloon suction conduit in the conduit switching valve of the endoscope of the Example of this invention. FIG. 3 is an enlarged longitudinal sectional view showing a state in which a contact plug of a pipe switching valve of the endoscope according to the embodiment of the present invention passes through a proximal end opening portion of a balloon suction pipe. It is an expanded longitudinal cross-sectional view of the contact plug part of the pipe line switching valve of the conventional endoscope. It is an expanded longitudinal cross-sectional view of the state which the contact stopper of the pipe line switching valve of the conventional endoscope passes the base end opening part of a balloon suction pipe line.

Explanation of symbols

8 Balloon suction line (fluid line)
8b Base end opening (opening)
9 Suction source pipe (fluid pipe)
11 Cylinder 14 Suction line switching piston 33 Bottomed hole 34 Contact plug

Claims (4)

A piston in which at least one of the plurality of fluid conduits is opened in an inner peripheral surface portion of a cylinder having a circular cross-sectional shape to which a plurality of fluid conduits are connected, and is movable in the axial direction in the cylinder. In the bottomed hole formed on the outer peripheral surface of the cylinder, a contact plug made of a resilient member for closing only the opening of the inner peripheral surface of the cylinder alone is crushed by the inner peripheral surface of the cylinder. In the endoscope line switching valve arranged in an elastically deformed state,
An endoscope pipe switching valve characterized in that an outer end surface of the contact plug is formed in a spherical shape having a smaller radius of curvature than a radius of an inner peripheral surface of the cylinder.   2. The outer end surface of the contact plug is located in the bottomed hole and is recessed from the outer peripheral surface of the piston at both end positions of the bottomed hole in the axial direction of the piston. Endoscope switching valve.   3. The outer end surface of the contact plug is also located in the bottomed hole and is recessed from the outer peripheral surface of the piston at both end positions of the bottomed hole in the circumferential direction of the piston. Endoscope pipe switching valve.   2. An inflatable / deflatable balloon is attached to the distal end of the insertion portion of the endoscope, and the opening that is blocked by the contact plug is an opening of a fluid conduit that communicates with the balloon. Or an endoscope conduit switching valve according to 3;

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