JP2856487B2 - Elastic seal member for pipe fittings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention is provided in a pipe joint used for connection between a plurality of pipes and connection between pipes and equipment. The present invention relates to an elastic seal member for a pipe joint that elastically abuts an inner peripheral surface of an end in a liquid-tight state.

(Prior Art) As a pipe joint used for interconnecting inner-surface resin-coated tubes in which the inner peripheral surface of a metal tube is coated with a synthetic resin layer, it has an anticorrosion function at the end of the connected tube. Threaded pipe fittings are known. For example, Japanese Unexamined Utility Model Publication No. 64-11492 discloses a tubular joint body in which an end of a pipe to be connected is inserted and screwed therein, and a pipe end inserted in the joint body. And a cylindrical fitting provided so as to be inserted into the pipe joint. In this pipe joint, an annular elastic seal member is externally fitted to the insertion portion. The elastic seal member has a circular cross section or a cross section that protrudes outward. The pipe to be connected is
It is inserted between the joint body and the insertion portion and screwed to the inner peripheral surface of the joint body. As the pipe is screwed into the joint body, the diameter is sequentially reduced, and the elastic seal member is pressed against the inner peripheral surface of the pipe in a liquid-tight manner. Thus, the liquid flowing through the pipe does not reach the end of the pipe inserted into the joint body, and therefore does not leak outside. Further, the end face of the pipe that is not coated with the synthetic resin However, it is surely protected.

(Problems to be Solved by the Invention) In such a conventional pipe joint, the elastic seal member is sufficiently compressed between the pipe inserted into the joint body and the insertion portion inserted into the pipe. Otherwise, the sealing function will not be sufficiently exhibited. However, when the end of the tube is screwed into the joint body, if the screwing amount is insufficient, the tube is not sufficiently reduced in diameter, and as a result, the elastic seal member is not sufficiently compressed. In this case, the sealing property between the end of the tube and the insertion portion is impaired by the elastic sealing member, the anticorrosion function of the end of the tube is not sufficiently exhibited, and further, there is a possibility that the liquid may leak to the outside. . Further, in a tubular body whose inner peripheral surface is covered with a synthetic resin layer, there is a possibility that the synthetic resin layer on the inner peripheral surface does not cover the inner peripheral surface with a uniform thickness. In such a case, when the elastic seal member comes into contact with the thin portion of the resin layer, the elastic seal member is not sufficiently compressed by the tube and the insertion portion, and the sealing function of the elastic seal member is impaired.

In order to prevent the sealing function from being deteriorated due to insufficient compression of the elastic seal member, it is conceivable to increase the thickness of the elastic seal member. In this case, however, a pipe having a thick resin layer on the inner peripheral surface is connected. Then, there is a problem that the elastic seal member is excessively compressed and its durability is impaired in a short time.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a pipe joint capable of stably exhibiting a sealing function without being affected by variations in the inner diameter of a pipe or variations in the screwing amount of the pipe. To provide an elastic sealing member. Another object of the present invention is to provide an elastic sealing member for a pipe joint which has excellent durability and can exhibit a sealing function stably for a long period of time.

(Means for Solving the Problems) The elastic sealing material for a pipe joint according to the present invention is provided with an insertion section in the pipe joint, and the insertion section is configured to elastically abut against an inner peripheral surface of an end portion of a connected pipe body. An annular elastic seal member that seals a contact portion with an inner peripheral surface of an end portion of the tubular body, and a lip portion that is in contact with the peripheral surface of the tubular body in a liquid-tight state on an outer peripheral surface. The lip part located on the distal end side of the insertion part, the surface located on the base end side of the insertion part is inclined, and is inclined to the distal end side of the insertion part on the inner peripheral surface of the end part of the pipe body The above-mentioned object is achieved.

(Function) In the elastic seal member of the present invention, the lip portion located at the distal end side of the insertion portion has a surface located at the base end portion of the insertion portion inclined, and the insertion portion has Contact while tilting to the tip side. Then, due to its own elastic force and the pressure in the tube, the base side surface of the insertion portion of the sharpened tip portion of the lip portion on the distal end side of the insertion portion extends over a predetermined length over the peripheral surface of the tube. Is strongly abutted.

(Examples) Hereinafter, the present invention will be described with reference to examples.

As shown in FIG. 1, the pipe joint elastic seal member 40 of the present invention is provided inside the pipe joint. The pipe joint is connected to, for example, a pipe body 10 which is an inner resin-coated pipe in which a synthetic resin layer 12 is coated on an inner peripheral surface of a metal pipe 11. The outer peripheral surface of the end of the tube body 10 is provided with a tapered male screw portion 13 whose outer diameter decreases gradually toward the end surface.

The pipe joint has a cylindrical joint main body 20, and this joint main body 20 has holding portions 21 provided at both ends (only one holding portion 21 is shown in FIG. 1). And a cylindrical connecting part 22 connecting the two holding parts 21. Each holding part 21 and the connecting part 22 are integrally manufactured from metal, and the inside of each holding part 21 has a larger diameter than the connecting part 22. Holder
The end of the tube 10 is inserted into the inside 21 to hold the end of the tube 10. The inner peripheral surface of the holding portion 21 has a tapered female screw portion 21 whose inner diameter is sequentially reduced from the opening end to the inner side.
The male thread 13 of the tube 10 is screwed to the female thread 21a. This female screw part in the holding part 21
A concave groove 21b is provided continuously with the female screw portion 21a on the inner peripheral surface further inside than the portion where the 21a is formed. The concave groove 21b has an annular shape that is continuous over the entire inner peripheral surface of the holding portion 21, and the concave groove 21b is continuous with the connecting portion 22.

In the joint body 20, a cylindrical sleeve 30 made of a synthetic resin is provided. The sleeve 30 is provided with a support portion 31 closely contacted so as to cover the inner peripheral surface of the connecting portion 22 in the joint body 20, and from the support portion 31 to the holding portion 21 of the joint body 20, the inside of the holding portion 21 The peripheral surface has an insertion portion 32 extending with a gap. The inner diameter and the outer diameter of the support portion 31 and the insertion portion 32 are equal to each other. In the continuous portion of the support portion 31 and the insertion portion 32,
An outwardly protruding engagement portion 33 is provided. The engaging portion 33
Has a continuous annular shape in the circumferential direction. The engaging portion 33
Is fitted into the concave groove 21b of the holding portion 21 of the joint body 20, and is bent toward the insertion portion 32 so that the distal end portion fits into the entire inside of the concave groove 21b. This engagement part 33
A gap is formed between the bent distal end portion 33a and the insertion portion 32, and the inner peripheral surface of the distal end portion 33a of the engaging portion 33 facing the insertion portion 32 has a holding portion 21 of the joint body. A tapered female screw portion 33b is formed to be continuous with the female screw portion 21a formed on the inner peripheral surface.

The insertion portion 32 of the sleeve 30 has an outer diameter slightly smaller than the inner diameter of the tube 10 to be connected. The distal end of the insertion portion 32 reaches almost the same position as the distal end of the holding portion 21 in the joint body 20, and the outer peripheral surface slightly away from the distal end toward the inner side has a concave groove 32a formed in an annular shape over the entire circumference. Is formed. The annular elastic seal member 40 of the present invention, which is pressed against the inner peripheral surface of the tube 10, is fitted into the concave groove 32.

As shown in FIG. 2, the elastic seal member 40 is provided with three lip portions 41, 42, and 43 arranged in parallel in the axial direction on the outer peripheral surface as seal portions that abut against the inner peripheral surface of the tubular body 10. And its cross section has a saw blade shape. Each lip part 41, 42, 43
Each has a triangular cross-section that becomes sharper as it goes outward, and is continuous in the circumferential direction. The lip portion 41 located on the distal end side of the insertion portion 32 has a surface located on the distal end side of the insertion portion 32 substantially orthogonal to the axial direction, and a surface located on the proximal end side of the other insertion portion 32 is inclined. Therefore, the cross section is a right triangle. The other lip portions 42 and 43 have a right-angled triangular cross section in which the surface located on the distal end side of the insertion portion 32 is inclined. The outer diameter at the tip of each of the lip portions 41, 42, and 43 is larger by a predetermined amount than the maximum inner diameter in consideration of variations in the thickness of the synthetic resin 12 of the tube body 10. Accordingly, the lip portions 41, 42, and 43 are pressed against the inner peripheral surface of the tubular body 10 screwed into the joint body 20 over a predetermined length, whereby the lip portions 41, 42 , 43 are deformed.

In the pipe joint of the present embodiment, the other end with the connecting portion 22 interposed therebetween has the same structure.

The operation when the pipe body 10 is connected to the pipe joint having such a configuration will be described. First, the end of the tube 10 is
Screwed between the holding part 21 of the tube 20 and the insertion part 32 of the sleeve 30, the male screw part 13 formed on the outer peripheral surface of the end of the tube 10
The female threaded portion 21a of the inner peripheral surface of the holding portion 21 in the joint body 20
To the screw.

The end of the tubular body 10 screwed into the holding portion 21 is inserted while the diameter of the male screw portion 13 on the outer peripheral surface is sequentially reduced by being screwed to the tapered female screw portion 21a of the holding portion 21. Externally fitted to the part 32.

At this time, the elastic sealing member 40 provided on the outer peripheral surface of the distal end side portion of the insertion portion 32 has two lip portions 42 and 43 located on the base end side of the insertion portion 32, as shown in FIG.
It is deformed to incline toward the base end of the insertion portion 32,
The lip part 41 located on the tip side of the insertion part 32 is
Deforms so that it tilts toward the tip of 32.

When screwing the end of the tube 10 into the holding portion 21 of the joint body 20, air existing in the space between the insertion portion 32 and the holding portion 21 is compressed by the end of the tube 10 to be screwed. . Therefore, when the tube 10 is screwed into the holding portion 21, the insertion portion
Lip 42 and 43 of the 32 elastic seal member 40 which is inclined toward the proximal end of, by the elastic force of the pressure P ₁ and its compressed air, is erected, located outside of the lip 42 and 43 Is pressed to the inner peripheral surface of the tube body 10 over a predetermined length. As a result, the gap between the outer peripheral surface of the insertion portion 32 and the inner peripheral surface of the tube 10 is reliably sealed by the lip portions 42 and 43.

Further, when the connected tube 10 the liquid is flowing, increased pressure of the tube body 10, its internal pressure P _2, the elastic sealing member
It acts so as to raise the lip portion 41 inclined to the tip side of the insertion portion 32 of 40. As a result, the tip located outside the lip portion 41 is crimped to the inner peripheral surface of the tube 10 over a predetermined length by this internal pressure and its own elastic force,
By the tip of the lip portion 41, the outer peripheral surface of the insertion portion 32 and the pipe 10
The space between the inner peripheral surface and the inner peripheral surface is securely sealed.

Thereby, the insertion portion 32 is sealed between the outer peripheral surface and the inner peripheral surface of the tube 10, and the end surface of the tube 10 that is not covered with the resin layer comes into contact with the liquid flowing through the tube 10. There is no danger and the liquid does not leak to the outside.

In this case, the pair of lip portions 42 and 43 positioned in the holding portion 21 inner back side of the elastic sealing member 40, the pressure P ₁ of the air to be compressed in accordance with the screwing of the tubular body 10 to become upright Te, because one of the lip portion 41 positioned in the holding portion 21 opening side by the internal pressure P ₂ of the tube 10 is upright state,
If the pressure P ₁ of the air to be compressed is greater than the internal pressure P ₂ of the tubular body 10, a more stable sealing effect can be obtained.

As shown in FIG. 4, the lip portion having a triangular cross section of the elastic seal member 40 has a vertex angle θ _{1 at the} tip end thereof.
Is within the range of 20 to 120 ° and the other angles θ ₂ and θ ₃ are within the range of 20 to 160 °, the elastic force of its own works effectively, and the sharpened tip provides a more reliable sealing function. Demonstrate.
It is preferable that the tip is as sharp as possible, but it may have a slight flat end surface or a rounded shape. Each surface forming the apex angle of the tip may be curved.

As described above, the pipe joint seal member 40 of the present invention includes a pipe body.
Each lip portion 41 to 43 which is a seal portion that contacts the inner peripheral surface of 10
Since the tip is sharpened, the tip is tilted and erected over a suitable length with a relatively small force. As a result, the pipe
Even if the inner peripheral surface of the pipe 10 is separated to some extent, there is no possibility that the tip end of each lip portion is surely separated from the inner peripheral surface of the pipe 10, and as a result, the inner circumference of the pipe 10 The surface and the outer peripheral surface of the insertion portion 32 are reliably sealed. Each lip portion is brought into close contact with the inner peripheral surface of the tube body 10 by not only its own elastic force but also the pressure applied to each lip portion. There is no possibility that the durability of the seal member 40 will be reduced.

The cross-sectional shape of the elastic seal member 40 is not limited to a triangular cross-section as shown in FIG. 2, for example, as shown in FIG.
It has four lip portions 41 to 44 as a seal portion, and each of the triangular cross sections has one lip portion 44 located on the base end side of the insertion portion 32 inclined to the base end side of the insertion portion 32. As described above, the other three lip portions 41, 42, and 43 may be tilted toward the distal end side of the insertion portion 32. With such cross-section, than the pressure P ₁ of the resulting compressed air with the screwing of the tubular body 10, when the internal pressure P ₂ of the tube 10 is large, Ru exhibited more effectively sealing function.

The or when the difference between the internal pressure P ₂ of the pressure P ₁ and the tubular body 10 of the compressed air due to the screwing of the tube 10 is large, the elastic seal member 40
As shown in FIG. 6, for example, the two lip portions 41 and 42 may have a triangular cross-section in which both of them are inclined in the same direction. Also, like when the difference between the internal pressure P ₂ at a pressure P ₁ and the tubular body 10 of the compressed air is small, the elastic sealing member 40, as shown in FIG. 7, the two lip portions 41 and
42, a triangular cross section as to stand in different directions by each of the pressure P ₁ and P _2, may be equally sealing function is exerted for any pressure.

Further, the elastic seal member 40 may be such that at least one of the plurality of seal portions has a lip portion having a triangular cross section as described above. For example, as shown in FIG. It may be configured in combination with a seal portion 49 which is circular and is compressed by contacting the inner peripheral surface of the tube 10. In the elastic seal member 40 having such a cross-sectional shape, the tip of the lip portion 41 having a triangular cross-section is securely abutted without separating from the inner peripheral surface of the tube 10, and the seal portion 49 having a circular cross-section is formed. By being compressed on the inner peripheral surface of the tube 10, a sealing effect with a large compressive force can be obtained.

The insertion portion 32 of the sleeve 30 inserted into the tube 10
For example, as shown in FIG. 9, a plurality of slits 34 extending in the axial direction are provided at appropriate intervals in the circumferential direction so as to reach the inside of the concave groove 32a in which the elastic seal member 40 is fitted from the tip thereof. It may be provided. With such a configuration,
A joint having the insertion portion 32 having the concave groove 32a can be easily formed by removing the swarf during injection molding.

(Effect of the Invention) In the elastic seal member for a pipe joint according to the present invention, the lip portion located on the distal end side of the insertion portion has an inclined surface located on the base end side of the insertion portion, and the inner periphery of the end portion of the pipe body Since it comes into contact with the surface while tilting to the tip side of the insertion part, the sealing function against the internal pressure of the tube is reliably demonstrated, and when the insertion amount of the tube is insufficient or when the inner diameter of the tube varies. In addition, the sealing function against the internal pressure of the tube is reliably exhibited. Since almost no compressive force is applied to the lip, the durability of the elastic sealing member is significantly improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a pipe joint having an elastic seal member for a pipe joint according to the present invention, FIG. 2 is a cross-sectional view showing the elastic seal member in an enlarged manner, and FIG. FIG. 4 is a schematic view for explaining the shape of the lip portion of the elastic seal member, and FIGS. 5 to 8 are each a view showing the use state of the elastic seal member of another embodiment of the present invention. FIG. 9 is a partially cutaway side view showing another example of the sleeve in which the elastic seal member is fitted. 10 ... tubular body, 20 ... fitting body, 22 ... holding part, 30 ... sleeve, 32 ... insertion part, 40 ... elastic sealing member, 41 ~
44 ... The lip part.

Claims (1)

(57) [Claims] An insertion portion is provided in a pipe joint, and is provided on the insertion portion so as to elastically abut against an inner peripheral surface of an end portion of a pipe to be connected. An annular elastic seal member for sealing the contact portion of
The pipe body has a lip portion abutting in a liquid-tight state on a peripheral surface of the pipe body, and a lip portion located at a distal end side of the insertion portion is inclined at a surface located at a base end side of the insertion portion, An elastic seal member for a pipe joint, wherein the elastic seal member is in contact with the inner peripheral surface of the end portion of the insertion portion in a state of being inclined toward the distal end of the insertion portion.