JP2017014781A - Fixation structure of annular elastic body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent slip-down of an annular elastic body, on the annular elastic body arranged in a flow passage of drain piping.SOLUTION: A check valve 1 as an annular elastic body is a substantially cylindrical elastic body composed of silicone rubber, and forms a flow passage of drain water on the inside. The check valve 1 comprises an annular part 15 having an opening part 11 on the upstream side and a flange part 12 projecting in the inward direction over the whole periphery from the upper end of the opening part 11. The check valve 1 is fitted to a projection strip part 24 of a cylindrical body part 2, and a ring body 3 is out-fitted to its outer periphery. The ring body 3 comprises a cylindrical ring part 31 and a presser part 32 projected toward the inside over the whole periphery from the upper end of the ring part 31, and a side surface of the opening part 11 is sandwiched from the inner-outer directions by the inner periphery of the ring part 31 and the outer periphery of the projection strip part 24, and an annular elastic body is fixed by sandwiching the flange part 12 from the vertical direction by an undersurface of the presser part 32 and an upper surface of the projection strip part 24.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an annular elastic body fixing structure disposed in a drain pipe.

  Various household facilities and equipment (hereinafter referred to as “drainage equipment”) that generate wastewater by use, such as washing machines, bathrooms, washstands, and sinks, are known. These drainage devices are provided with drainage piping in order to treat wastewater generated by use to the sewage side. These drainage pipes are provided with an annular elastic body such as a backflow prevention valve for preventing the backflow of odors, pests and the like, and a packing for the purpose of water stoppage or the like in the flow path. Below, the fixing structure of the conventional backflow prevention valve is demonstrated as an example of the fixing structure of an annular elastic body.

The drainage pipe shown in FIG. 9 is composed of a backflow prevention valve, a first ring body, a second ring body, and a tubular member as an annular elastic body.
The backflow prevention valve is made of an elastic material, has a substantially cylindrical shape, has an opening at the upstream end, and the downstream end abuts against the opposite side surfaces, and closes when no load is applied. And it consists of the obstruction | occlusion part opened by applying a fixed pressure inside. In addition, the opening is provided with a flange that protrudes inward and outward.
The first ring body is a ring-shaped member having an outer peripheral surface that matches the inner peripheral surface of the opening of the check valve body.
The second ring body is a ring-shaped member having an inner peripheral surface that matches the outer peripheral surface of the opening of the check valve body.
The cylindrical member is a member that is separated into upper and lower portions using screws, and accommodates the backflow prevention valve main body, the first ring body, and the second ring body therein.

The check valve configured as described above is constructed as follows.
The first ring body is disposed inside the opening and the second ring body is disposed outside the backflow prevention valve body, and the first ring body and the second ring body respectively The opening is sandwiched inward and outward.
Furthermore, after arranging the backflow prevention valve in the tubular member, the second ring body is sandwiched between the upper and lower tubular members, and the construction of the backflow prevention valve described in Patent Document 1 is completed.
The backflow prevention valve configured as described above is further used for the treatment of drainage flowing through the drainage pipe by connecting the upper end / lower end of the cylindrical member to the drainage pipe.
In the drainage pipe using the backflow prevention valve described in Patent Document 1 described above, when drainage occurs in the drainage pipe, the drainage flows into the backflow prevention valve from the upstream end of the tubular member. When drainage accumulates to some extent inside the backflow prevention valve, the lower blockage of the backflow prevention valve body is pushed out from the inside by the water flow and its own weight, and the wastewater is discharged into the cylindrical member below and connected as it is. It is discharged to the sewage side through the drainage pipe. When drainage is completed, when the amount of water inside the check valve is sufficiently reduced, the blocking portion is closed again by the elasticity of the check valve, and drainage is completed.

JP 2012-180656 A

In the conventional structure for fixing the annular elastic body (backflow prevention valve), the backflow prevention valve may slide down when some stress is applied to the backflow prevention valve during cleaning or maintenance. That is, since the backflow prevention valve is made of an elastic material, when the stress is applied, the backflow prevention valve expands and is sandwiched between the first ring body and the second ring body along with the expansion. The thickness of the part is thinned and slides down. Further, the backflow prevention valve is provided with a flange at the upstream end, but the first ring body also slides down at the time of the sliding down. Accordingly, as shown in FIG. 10, since the heel portion is deformed to be bent inward as shown in FIG. 10, it is difficult to prevent the heel portion from sliding down.
And since the backflow prevention valve is arranged in the flow path of the drainage pipe, if the backflow prevention valve slides down, the pipe may be clogged by the backflow prevention valve, and the backflow prevention valve slipped down into the drainage pipe. It was very difficult to recover.

  This invention is invented in view of the said problem, Comprising: It aims at preventing sliding of an annular elastic body about the annular elastic body arrange | positioned in the flow path of drainage piping.

The present invention according to claim 1 is a structure for fixing an annular elastic body disposed in a flow path of a drain pipe,
Made of elastic material,
An annular elastic body comprising an annular portion provided with an opening therein, an inner peripheral surface on the opening portion side, and a collar portion provided around the entire periphery so as to protrude inward along the inner periphery;
A cylindrical part made of a hard material,
A ridge portion provided at the end of the cylindrical body portion and having an outer peripheral shape that matches the inner peripheral shape of the opening of the annular elastic body, provided on the entire periphery so as to protrude outward along the outer shape. When,
A ring portion having an inner peripheral shape substantially the same as the outer peripheral shape of the opening of the annular elastic body, and a holding portion provided on the entire periphery so as to protrude inward along the inner periphery on the inner peripheral surface of the ring portion; A ring body consisting of
Consists of
The protruding portion of the cylindrical body portion is accommodated in the opening portion of the annular elastic body, and the ring portion of the ring body is attached to the outer periphery of the opening portion of the annular elastic body with the flange portion and the protruding portion in contact with each other. The annular elastic body is characterized in that the opening portion of the annular elastic body is sandwiched and fixed between the protruding portion of the cylindrical body portion and the ring body by further fitting and pressing the pressing portion against the collar portion. It is a fixed structure.

  The present invention according to claim 2 is provided with a closing portion that is opposed to the one end of the annular elastic body, facing each other, closing when no load is applied, and opening by applying a constant pressure inside. 2. The annular elastic body fixing structure according to claim 1, wherein the annular elastic body is a backflow prevention valve.

  The present invention described in claim 3 is characterized in that the cylindrical body portion is provided with a second protrusion that presses the ring portion of the ring body toward the flange side of the annular elastic body. Item 3. The structure for fixing an annular elastic body according to Item 2.

  According to the fourth aspect of the present invention, when the annular elastic body is inserted into the annular portion of the ring body, if the direction of the annular portion of the ring body is wrong, the annular portion of the ring body is placed around the opening. The structure for fixing an annular elastic body according to any one of claims 1 to 3, further comprising a structure for preventing erroneous insertion so as not to be fitted.

  The present invention according to claim 5 is provided with a ring body holding portion at both ends of the ring body, and the ring body can be fitted to the annular elastic body from either end of the ring body. The fixing of the annular elastic body according to any one of claims 1 to 3, wherein the holding portion of the body abuts on the collar portion and is fitted on the outer periphery of the opening of the annular elastic body. Structure.

  The present invention according to claim 6 is characterized in that the opening portion, ring body, and cylindrical body portion of the check valve are provided with a substantially circular shape in the axial direction. It is the fixation structure of the cyclic | annular elastic body as described in any one.

According to the first aspect of the present invention, the pressing portion provided on the ring body is brought into contact with the collar portion, thereby preventing slipping due to deformation of the annular elastic body and preventing sliding of the ring body itself. Can do. In addition, by externally fitting the ring body to the annular elastic body, it is possible to prevent deformation caused by other members coming into contact with the outer periphery of the annular elastic body. When the annular elastic body is a backflow prevention valve as described in claim 2, it is possible to prevent deformation of the closed portion of the backflow prevention valve, and the ring body serves as a guide to Workability is improved.
According to the third aspect of the present invention, the collar portion is sandwiched in the vertical direction by the ring body, so that the annular elastic body and the ring body can be prevented from slipping down.
According to this invention of Claim 4 and Claim 5, it becomes possible to improve the workability of a ring body.
According to this invention of Claim 6, it becomes possible to clarify the structure of a backflow prevention valve.

It is the A section enlarged view of (a) sectional view (b) and (a) which shows the construction state of the present invention. It is an exploded sectional view showing each member of an embodiment. It is (a) top view (b) front view of a cylinder part. It is (a) sectional drawing (b) A part enlarged view which shows a ring body. It is the A section enlarged view of (a) reference view (b) and (a) which shows the deformation state of the collar part vicinity at the time of a backflow prevention valve sliding down. It is sectional drawing which shows the construction state of 2nd embodiment. It is the A section enlarged view of (a) sectional view (b) and (a) which shows the construction state of a third embodiment. It is the A section enlarged view of (a) sectional view (b) and (a) which shows the ring object of a fourth embodiment. It is sectional drawing which shows the conventional fixing structure. It is a reference figure which shows the deformation | transformation state of the collar part vicinity at the time of a backflow prevention valve sliding down.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The following description is for facilitating understanding of the embodiment, and the present invention is not limited and understood by this. In the following embodiments, the vertical and horizontal directions and the positional relationship will be described with reference to the construction state shown in FIG.

  The first embodiment of the present invention relates to a structure for fixing an annular elastic body, which will be described below. As shown in FIG. 1, a vertical tube 100 buried under the floor and a screw on the upper end of the vertical tube 100 are provided. It arrange | positions in the flow path of the drain piping which consists of the drainage metal fitting 200 combined. The annular elastic body in the first embodiment is a backflow prevention valve.

The vertical pipe 100 is a metal pipe body, and a drain trap (not shown) is continuous on the downstream side thereof. The vertical tube 100 has a male screw part on the outer periphery of the upper end, and is screwed into the drainage fitting 200 by the male screw part.
The drainage fitting 200 is a metal cylindrical member, has a flange portion protruding outward at the upper end, and has a metal pan 300 on the inner periphery, and is formed on the inner periphery of the drainage fitting 200. The eye plate 300 is fixed by engaging a protrusion formed on the lower end of the eye plate 300 with the inward flange.

The backflow prevention valve 1 is a substantially cylindrical elastic body made of silicon rubber or the like, and has a drainage channel formed therein. In addition, on the upstream side, the backflow prevention valve 1 has an annular portion 15 having an opening portion 11, a flange portion 12 projecting inward from the upper end of the opening portion 11 over the entire circumference, and opposing surfaces gradually. An inclined portion 13 provided so as to be close to each other and a closing portion 14 that is formed at the tip of the inclined portion 13 and closes the flow path when the opposing surfaces come into contact with each other.
Here, the closing part 14 will be described in detail. The closing part 14 is closed by maintaining the contact state between the opposing surfaces by its own elasticity, and the upstream side of the check valve 1 is downstream. As long as no gas or fluid passes therethrough, the blockage of the flow path is maintained.

  As shown in FIGS. 1 and 2, the backflow prevention valve 1 is disposed in the flow path of the drainage pipe by the cylindrical body portion 2, the ring body 3, and the receiving metal fitting 4.

  The cylindrical portion 2 is an attachment member made of a hard synthetic resin. A handle portion 21 having a cross-sectional arc shape is provided in the radial direction of the upper surface, and an engaged portion 43 of a receiving metal fitting 4 to be described later is provided on the outer periphery of the upper surface. The engaging portion 22 that engages with the projection protrudes upward. The engaging portion 22 has an inclined portion that gradually protrudes upward as it proceeds counterclockwise in plan view, and is formed at two positions that are rotationally symmetric about the axis of the cylindrical body portion 2. Further, as shown in FIG. 3, a groove 23 is formed between the engaging portions 22. Further, the cylindrical body portion 2 is formed with a protrusion 24 protruding outward at the lower end of the side surface, and a second protrusion 25 protruding further outward than the protrusion 24 above the protrusion 24. Has been. An annular packing 26 is fitted over the second protrusion 25.

  As shown in FIGS. 2 and 4, the ring body 3 includes a cylindrical ring portion 31, a pressing portion 32 projecting inward from the upper end of the ring portion 31 over the entire circumference, and a ring portion 31. It is comprised from the convex part 33 which protruded below the lower end as an incorrect insertion prevention structure. Moreover, the pressing part 32 is provided with the inclined surface which inclines below as it goes inside on the upper surface.

The receiving metal fitting 4 is a cylindrical member made of a metal material such as stainless steel, and has a flange portion 41 projecting outward from the upper end over the entire circumference. The outer diameter of the metal fitting 4 is reduced through a step 42 formed so as to protrude inward in the vicinity of the center, and the outer circumference of the metal fitting 4 is pressed above the step 42. Two engaged portions 43 formed so as to protrude toward the inner peripheral side are provided.
In addition, the receiving metal fitting 4 is fitted with a packing 5 having a substantially triangular shape in cross section in the lower portion of the flange portion 41.

  Here, the outer diameter of the upper end of the cylindrical portion 2 is substantially the same as the inner diameter of the upper portion of the stepped portion 42 of the receiving metal fitting 4, and the outer diameter of the second protrusion 25 is the stepped portion 42 of the receiving fitting 4. It is substantially the same as the inner diameter of the lower part.

  Below, the construction of the check valve 1 will be described.

First, the diameter of the annular portion 15 is increased so that the flange portion 12 of the backflow prevention valve 1 is disposed above the protrusion portion 24, and the backflow prevention valve 1 is fitted to the protrusion portion 24 of the cylindrical body portion 2. Let Then, the ring body 3 is fitted onto the opening 11 of the check valve 1 while pulling the check valve 1 in the disengagement direction (downward in FIG. 1). At this time, by attaching the ring body 3 while pulling the backflow prevention valve 1, a gap is formed between the upper end of the backflow prevention valve 1 and the second protrusion 25, and the pressing portion 32 is disposed in the gap. The Further, the pressing portion 32 can be reliably arranged by the inclined surface formed on the upper surface of the pressing portion 32.
By arranging the pressing portion 32 at the location, the upper end of the ring body 3 comes into contact with the lower surface of the second protruding portion 25, and the pressing portion 32 presses the upper surface of the flange portion 12 downward (the protruding portion 24). Therefore, the side surface of the opening portion 11 is sandwiched from the inner and outer directions by the inner periphery of the ring portion 31 and the outer periphery of the ridge portion 24, and the flange portion 12 is sandwiched by the lower surface of the pressing portion 32 and the upper surface of the ridge portion 24 from the vertical direction. The Since the ring body 3 is formed with a convex portion 33 as a structure for preventing erroneous insertion, when the mounting direction of the ring body 3 is wrong, the convex portion 33 comes into contact with the second protrusion 25 and the ring body 3 It is formed so that the body 3 cannot be externally fitted to the check valve 1.
Next, the drainage metal fitting 200 is screwed into the vertical pipe 100 in a state where the receiving metal fitting 4 is placed on the upper end of the vertical pipe 100 partially buried under the floor. At this time, the receiving metal fitting 4 is sandwiched between the vertical pipe 100 and the drainage metal fitting 200 along with the screwing, but the packing 5 disposed below the flange portion 41 of the receiving metal fitting 4 has a substantially triangular shape in cross section. The position of the receiving metal fitting 4 is corrected so that the central axis of the vertical pipe 100 and the drainage metal fitting 200 coincides with the central axis of the receiving metal fitting 4 according to the screwing.
Next, concrete or the like is driven into the exposed portion of the vertical pipe 100 and the outside of the drainage fitting 200 to form a floor surface that is flush with the upper surface of the drainage fitting 200.
And from the upper part of the drainage metal fitting 200, the convex part 33 formed in the inner periphery of the back fitting prevention valve 1, the cylindrical part 2, and the ring body 3 assembled as mentioned above is a groove part of the cylindrical part 2. Insert to match 23. And after inserting until the to-be-engaged part 43 is located above the upper surface of the cylinder part 2, by rotating the cylinder part 2, the engagement part 22 and the to-be-engaged part 43 are engaged, and a backflow is carried out The prevention valve 1 is fixed in the drainage channel. At this time, the packing 26 fitted to the outer periphery of the cylindrical body portion 2 abuts on the inner periphery of the receiving metal fitting 4 to connect the outer periphery of the cylindrical body portion 2 and the inner periphery of the receiving metal fitting 4 in a watertight manner. Accordingly, all of the waste water flowing from the drainage fitting 200 flows into the backflow prevention valve 1.
Finally, the eye plate 300 is placed on the drainage fitting 200 to complete the construction.

  When performing cleaning and maintenance of the backflow prevention valve 1, the handle portion 21 is gripped, and the cylindrical portion 2 is rotated in the direction opposite to that at the time of attachment. The backflow prevention valve 1 can be removed from the flow path.

When drainage flows from the upstream side (drainage fitting 200) to the check valve 1 that has been constructed as described above, the drainage flows into the check valve 1 from the opening 11 of the check valve 1. And the waste water which flowed into the backflow prevention valve 1 applies stress to the inclined portion 13 and the closed portion 14 from the inside based on the water force and its own weight, and opens the flow path by expanding the closed portion 14, and the downstream side Is discharged. The drainage discharged to the downstream side of the backflow prevention valve 1 is discharged to a drainage trap (not shown) formed on the downstream side of the vertical pipe 100 and further to a drainage pipe on the downstream side. When the inflow of the waste water from the upstream side is finished and the waste water inside the backflow prevention valve 1 is discharged, the closing portion 14 closes the flow path again by its own elasticity.
On the other hand, when a backward flow of fluid such as drainage or gas occurs from the downstream side, the inclined portion 13 and the closing portion 14 are subjected to stress from the outside to the inside, and the contact surfaces of the closing portion 14 come into stronger contact with each other. Thus, the blocking of the blocking portion 14 is maintained, and odors, drainage, and the like are prevented from flowing back upstream from the backflow prevention valve 1. Therefore, even if the sealing water in the drain trap formed on the downstream side of the vertical tube 100 evaporates due to reasons such as long-term non-use, odors and pests do not flow backward.

  In the first embodiment, the ring body 3 is fitted on the opening 11 of the backflow prevention valve 1 as an annular elastic body, and the flange 12 cannot be expanded in the outward direction. It does not slide down from part 2.

Here, the slip prevention effect of the backflow prevention valve 1 by the ring body 3 is explained in full detail regarding said 1st embodiment. First, when any stress is applied to the backflow prevention valve 1 in a state where the ring body 3 is not attached, as shown in FIG. Will be released.
On the other hand, when the ring body 3 is externally fitted to the opening 11 of the check valve 1 as in the first embodiment, the collar portion 12 is deformed by the ring portion 31 and the pressing portion 32. I can't. In particular, when the check valve 1 slides down, the corner portion on the outer side of the upper end of the flange portion 12 is deformed (expanded) the most, but the corner portion on the inner periphery of the ring body 3 composed of the ring portion 31 and the holding portion 32 is concerned. It is in covering and the deformation is suppressed. That is, since the sliding-down of the check valve 1 is accompanied by the deformation of the flange 12, in the present invention, the ring body 3 suppresses the deformation of the flange 12 to prevent the check valve 1 from sliding down. Yes. Moreover, since the holding | suppressing part 32 is arrange | positioned between the backflow prevention valve 1 upper end and the 2nd protrusion part 25, while holding | suppressing part 32 plays the role of the wedge and clamps the collar part 12 to an up-down direction, a ring The body 3 itself is prevented from sliding down. Therefore, the ring body 3 does not slide down together with the backflow prevention valve 1 as in the prior art.

  Moreover, the ring body 3 also has operational effects other than the above-described sliding-off preventing effect. For example, since the ring body 3 is attached to the outer periphery of the backflow prevention valve 1, the backflow prevention valve 1 is prevented from coming into direct contact with the receiving metal fitting 4 at the time of attachment. Accordingly, there is no possibility that the backflow prevention valve 1 is deformed by friction with the receiving metal fitting 4 during construction, and a gap is generated in the closed portion 14. In addition, the outer periphery of the ring body 3 serves as a guide during construction, and the backflow prevention valve 1 and the cylindrical body portion 2 are prevented from being inclined and inserted.

  Although the first embodiment of the present invention is as described above, the present invention is not limited to the shape of the above-described embodiment, and can be freely changed without departing from the gist thereof. For example, the backflow prevention valve 1 of the present invention is disposed between the vertical pipe 100 buried under the floor and the drainage fitting 200. However, as in the second embodiment shown in FIG. 6, the drainage trap buried under the floor. 7 may be arranged. In this case, instead of changing the sealing height of the drain trap 7 as much as possible, in the first embodiment, instead of the packing 5 having a substantially triangular shape in cross section provided in the receiving metal fitting 4, a substantially U shape in cross sectional view. A mold packing 51 is fitted to the flange portion 41. In addition, since the backflow prevention valve 1, the cylinder part 2, the ring body 3, and the receiving metal fitting 4 are the same as said 1st embodiment, the description is abbreviate | omitted.

In the first embodiment, the annular elastic body is the backflow prevention valve 1, but the annular elastic body is not limited to the backflow prevention valve 1. In the third embodiment shown in FIG. 7, the annular elastic body is an annular packing 6 that is externally fitted to the deodorizing pipe 8 that is disposed in the drain trap 71 and forms sealed water.
The packing 6 has an annular shape made of an elastic body such as rubber, and includes an annular portion 63 having an opening 61 therein, and a flange portion 62 projecting inward over the entire circumference at the upper end of the annular portion 63. ing.
The deodorizing pipe 8 has a substantially cylindrical shape having a flange portion at the upper end, and at the time of construction, the lower end is disposed in the drainage stored in the drain trap 7 so that a part of the channel is drained. Satisfy and prevent backflow of odors and pests. The deodorizing pipe 8 forms a protruding ridge 81 that protrudes outward below the flange portion, and a packing 6 that is an annular elastic body is fitted to the protruding ridge 81, and on the outer periphery of the packing 6, A ring body 3 is attached. The ring body 3 has the ring part 31 and the pressing part 32 similarly to the ring body 3 of the first embodiment.
In the second embodiment, the pressing portion 32 of the ring body 3 is disposed between the flange portion and the packing 6, and the upper end of the pressing portion 32 contacts the lower surface of the flange portion, so that the pressing portion 32 is The upper surface of the portion 62 is pressed downward. That is, in the second embodiment, the flange portion formed at the upper end of the deodorizing pipe 8 functions as the second protrusion 82.

  In the first embodiment, the ring body 3 has the convex portion 33 as an erroneous insertion prevention mechanism at the lower end. However, the shape and position of the erroneous insertion prevention mechanism can be appropriately changed. Further, as in the fourth embodiment shown in FIG. 8, by providing the holding portions 32 at the upper and lower ends of the ring body 3, a vertically symmetrical shape is provided, and the ring body 3 can be externally fitted even if it is turned upside down. It is possible to adopt a shape that can prevent the erroneous insertion, and the erroneous insertion prevention mechanism may be configured with this structure.

DESCRIPTION OF SYMBOLS 1 Backflow prevention valve 11 Opening part 12 Gutter part 13 Inclination part 14 Closure part 15 Annular part 2 Tubular part 21 Handle part 22 Engagement part 23 Groove part 24 Projection part 25 Second projection part 26 Packing 3 Ring body 31 Ring part 32 Holding part 33 Convex part 4 Receptacle part 41 Flange part 42 Step part 43 Engagement part 5, 51 Packing 6 Packing 61 Opening part 62 Gutter part 63 Annular part 7, 71 Drain trap 8 Deodorant pipe 81 Projection part 82 Second Projection 100 Vertical pipe 200 Drainage fitting 300 Eye plate

Claims (6)

It is a fixing structure of an annular elastic body arranged in the flow path of the drain pipe,
Made of elastic material,
An annular elastic body comprising an annular portion provided with an opening therein, an inner peripheral surface on the opening portion side, and a collar portion provided around the entire periphery so as to protrude inward along the inner periphery;
A cylindrical part made of a hard material,
A ridge portion provided at the end of the cylindrical body portion and having an outer peripheral shape that matches the inner peripheral shape of the opening of the annular elastic body, provided on the entire periphery so as to protrude outward along the outer shape. When,
A ring portion having an inner peripheral shape substantially the same as the outer peripheral shape of the opening of the annular elastic body, and a holding portion provided on the entire periphery so as to protrude inward along the inner periphery on the inner peripheral surface of the ring portion; A ring body consisting of
Consists of
The protruding portion of the cylindrical body portion is accommodated in the opening portion of the annular elastic body, and the ring portion of the ring body is attached to the outer periphery of the opening portion of the annular elastic body with the flange portion and the protruding portion in contact with each other. The annular elastic body is characterized in that the opening portion of the annular elastic body is sandwiched and fixed between the protruding portion of the cylindrical body portion and the ring body by further fitting and pressing the pressing portion against the collar portion. Fixed structure.   One end of the annular elastic body is in contact with opposite side surfaces, closed when no load is applied, and provided with a closed portion that is opened by applying a certain pressure inside, the annular elastic body is used as a backflow prevention valve. The structure for fixing an annular elastic body according to claim 1, wherein the structure is fixed.   3. The fixing of the annular elastic body according to claim 1, wherein the cylindrical body portion is provided with a second protrusion that presses the ring portion of the ring body toward the flange portion side of the annular elastic body. Construction.   When inserting the annular elastic body into the annular portion of the ring body, if the direction of the annular portion of the ring body is wrong, the annular portion of the ring body is prevented from being externally fitted around the opening. The annular elastic body fixing structure according to any one of claims 1 to 3, further comprising:   Even if the ring body is provided with both ends of the ring body, and the ring body is fitted on the annular elastic body from either end of the ring body, the ring body is held against the collar. The annular elastic body fixing structure according to any one of claims 1 to 3, wherein the structure is externally fitted to an outer periphery of an opening of the annular elastic body.   The annular elastic body according to any one of claims 1 to 5, wherein the opening, the ring body, and the cylindrical body portion of the backflow prevention valve have a substantially circular shape in the axial direction. Fixed structure.

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