JPS601344Y2 - flexible expansion joint - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pipe joint that is three-dimensionally movable and axially expandable and contractible.

[Prior art]

Flexible expansion joints used for connecting pipes for water supply, sewerage, and industrial water supply, distribution, and drainage are required to be capable of bending, stretching, contracting, and eccentricity, as well as having pressure resistance and durability.

By the way, the conventional flexible joint of this type has 1
A pair of caps 1' are connected by a tubular flexible part 2' mainly composed of a comb layer, and a steel ring 6' is used to maintain strength against internal and external pressure.

6'' is buried in the inner and outer layers of the rubber layer 4'' so as not to overlap.

[Problem that the invention attempts to solve]

The above-mentioned conventional flexible joint has an elastic rubber layer and a rigid steel ring 6 when expansion and contraction occurs after installation.
The adhesive strength is reduced at the bonding surface with the steel rings, causing a peeling phenomenon, and the rubber layer between the steel rings deteriorates due to repeated distortion due to buckling, etc., resulting in a loss of strength and durability. There was a problem.

Furthermore, if eccentricity occurs at the connecting portion of the installed piping due to poor ground conditions, etc., the portion of the rubber layer 4' with a larger radius of curvature will stretch and conversely, the portion with a smaller radius of curvature will compress and deform.

In particular, a strong tensile force is generated on the rubber layer side with a large radius of curvature at the connection between the tubular flexible part 2' and the cap 1'.
If an excessive tensile force is applied compared to the adhesive force between the rubber layer 4' and the dubbling rib tube 3' provided at the connecting end of the cap 1', separation will occur at this boundary and the tubular flexible There is a drawback that the end of the portion 2' separates from the base 1'.

In an attempt to solve this drawback, a flexible stretchable material is constructed by embedding a woven fabric in the rubber layer between the inner and outer steel rings 6' and 6'', which are double-layered in the tubular flexible portion 2'. Some joints have been proposed, but this also uses steel rings 6
Although the peeling phenomenon of the tubular flexible portion 2' and 6'' can be improved to some extent, the effect of preventing the tubular flexible portion 2' from coming off from the cap 1' cannot be expected, and it cannot be called a fundamental solution. Ta.

The present invention was developed in an attempt to eliminate each of the above-mentioned defects by focusing on such conventional problems, and the pressure resistance and durability are impaired accordingly in response to both expansion, contraction and bending phenomena. We provide a flexible expansion joint that can exhibit stable performance without any problems, and can also guarantee a strong connection between the base and flexible pipe for a long period of time, thereby improving water supply and drainage. The aim is to achieve permanent stability and achieve economic advantages by reducing equipment costs.

[Means for solving problems]

Therefore, the present invention provides a flexible expansion joint in which a pair of bases forming a joint part and connecting ends around which stop rings are connected to each other by a tubular flexible part, wherein the tubular flexible part has one At least one set of bias cord reinforcing layers is installed between one stop ring of one connection end and the opposite stop ring of the other connection end, so that the cord is
The cord is embedded between the inner layer rubber and the outer layer rubber, at least at the connecting end, over the entire circumference, forming an intersecting angle of ~45°, and the end of the cord is fixed to the ring that is in contact with both stop rings. At the same time, at least one radial cord reinforcing layer is provided inside the bias cord reinforcing layer so that the cords thereof form an intersecting angle of 10 to 25 degrees with respect to the circumferential direction, and between the inner layer rubber and the outer layer rubber, the entire periphery is provided. It is characterized in that it is buried across the entire length and its ends are brought into contact with each of the stop rings.

[Effect]

In the present invention having such a means, the radial cord reinforcing layer exhibits great resistance to pressure in the direction of expansion, and the waist bias cord reinforcing layer functions to stabilize the shape and strengthen the connection with the base. The cord reinforcement layer is resistant to abnormal elongation deformation.

In this way, it exhibits sufficient performance in terms of pressure resistance and durability while being adaptable to bending, stretching, contraction, and eccentricity.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a longitudinal cross-sectional view of a part of a flexible expansion joint according to an example of the present invention, which is a cross-sectional view of a pair of caps 1 used as a joint and a bridge between both caps 1. A tubular flexible part 2 joined to the connecting end of the cap 1 is a constituent member, and a stop ring 3 is fixed by welding or the like around the circumference of the connecting end of the cap 1. The stop ring 3 is formed into a rib or protrudes in the radial direction from the circumferential surface of the base 1.

The rubber layer of the tubular flexible portion 2 is comprised of an outer rubber layer 4, an inner layer comb 9, a cover rubber 10, and both stop rings 3, 3.
A pair of bias cord reinforcing layers 7, 7 separated in the axial direction are arranged around the entire circumference on the outside of the radial cord reinforcing layer 5 extending over the entire length and the entire circumference between the radial cord reinforcing layers 5 and 5. It has a structure in which its ends are wrapped around both rings 8 such as bead wires, folded back and tightened with a metal wire or the like, and fixed to both stop rings 3.

FIG. 3 shows only the main parts of a modification of the structure shown in FIG. 2, particularly suitable for large-diameter flexible expansion joints,
Two sets of bias cord reinforcing layers 7 are disposed outside the radial cord reinforcing layer 5 over the entire length and circumference between both stop rings 3, and the ends thereof are wound around two bead wires 8, 8 respectively and folded back. It has a structure that is fixed to the stop ring 3.

At this time, the two sets of bias cord reinforcing layers 7 can also be wound around one bead wire and folded back.

In any of the above structures, all reinforcing layers are interposed between the outer rubber layer 4 and the inner rubber layer 9 of the tubular flexible portion 2.

4 and 5 schematically show the cord intersection angle of the reinforcing layer embedded in the tubular flexible portion 2 of the expandable flexible joint according to the present invention. The part that was rolled and folded over was omitted.

That is, as shown in FIG. 4, one layer of radial cord reinforcing layer 5 substantially parallel to the circumferential direction is provided between the outer rubber layer 4 and the inner rubber layer 9.
is buried so as to be in contact with both stop rings 3, and
A bias cord reinforcing layer 7 having a cord crossing angle of 10 to 45 degrees is buried on the outside thereof as a pair of axially separated reinforcing layers at least at the connecting end, and the end of the reinforcing layer 7 is wound around the bead wire 8. The attached is a folded structure,
This corresponds to the structure shown in FIG. 2 above.

In addition, FIG. 5 shows that between the outer rubber layer 4 and the inner rubber layer 9 there are
Bias cord reinforcement layer 7 having a cord crossing angle of 45°
Although not shown, the radial cord reinforcing layer 5 is separated in the axial direction and buried as a pair on the connection end side, and the end of the reinforcing layer is wrapped around the bead wire 8 and folded back.

In both cases of FIG. 4 and FIG. 5, the bias cord reinforcing layer 7 is shown as a pair of reinforcing layers separated in the axial direction, but the bias cord reinforcing layer 7 is shown as a pair of reinforcing layers separated in the axial direction. It is also possible to have a structure in which the bias cord reinforcing layer 7 and the radial cord reinforcing layer 5 are both separated in the axial direction.

As mentioned above, in the flexible expansion joint according to the present invention,
The tubular flexible part 2 is made of a rubber layer of an appropriate thickness, and is made up of an outer rubber layer 4 and an inner rubber layer 9, and the surface layer is covered with a cover rubber 10 if necessary.

As the rubber raw material used for the tubular flexible part 2, either natural rubber or synthetic rubber can be used as long as the JIS hardness is in the range of 40 to 80 degrees, and rubber compounds with excellent weather resistance and durability are preferred. .

Therefore, one example of the rubber raw material used for the tubular flexible portion 2 is a combination such as natural rubber or chlorinated rubber for the inner and outer layers and chlorinated comb for the surface layer.

As the reinforcing layer, a combination of at least one bias cord layer 7 and at least one radial cord reinforcing layer 5 is used. The ends of the cord layer 7 are attached to both stop rings 3
It is wound around both rings 8 such as bead wires adjacent to the stop ring 3, folded back, and tightened with a metal wire or the like to be physically fixed to both stop rings 3.

The reinforcing layer is a sheet-like thin layer made of rubberized cord fabric. Inorganic fibers such as synthetic fibers such as polyester and polyamide steel cord can be used as raw materials for cord fabric, and tire cords made of these fibers can be used as raw materials. Particularly preferred.

In the present invention, one set of bias cord reinforcing layers 7 refers to two
This refers to a reinforcing layer in which two thin layers are stacked one on top of the other, and the cords thereof form an intersecting angle of 10 to 45° with respect to the circumferential direction.

Further, the pair of bias cord reinforcing layers 7, 7 separated in the axial direction means that the pair of bias cord reinforcing layers 7 does not extend over the entire length between both bead wires.

As shown in FIGS. 4 and 5, this refers to a reinforcing layer that is separated in the axial direction and is disposed around the entire circumference only at the connecting ends including the folded portions of both bead wires 8.

For these bias cord reinforcing layers 7, stretchable cords such as the above-mentioned fibers are usually used.

A single layer of radial cord reinforcing layer 5 is a thin layer extending over the entire length and circumference between both stop rings, and whose cords intersect with the circumferential direction at an intersecting angle of O to 25 degrees, preferably substantially parallel to S. It means one layer of the body.

For the radial cord reinforcing layer 5, a synthetic fiber cord having the elasticity of a non-stretchable cord such as a steel cord is also used.

In addition, in the above, the crossing angle of the bias code is 10 to 4.
The reason for setting the angle to 5° is that if it is less than 100°, it will become close to a radial cord, and the appropriate elongation of the rubber layer in the longitudinal direction of the pipe will be hindered.
Moreover, if the angle exceeds 45°, there will be a problem in the role of regulating abnormal elongation, and the reinforcing effect will be diminished.

Also, the upper limit of the intersection angle of the radial cord is set to 25° because
If it exceeds this, the radial cord becomes meaningless, and its effectiveness in preventing swelling in the radial direction and preventing breakage due to pressure decreases.

In order to allow this radial cord reinforcing layer 5 to fully fulfill the above-mentioned role, both ends of the radial cord reinforcing layer 5 are brought into contact with the stop ring 3.

For both stop rings 3 of both bases 1, a known dubbling rib tube may be used, or various rings such as a ring made of round wire may be used.

The outer rubber layer 4, reinforcing layers 7 and 5, inner rubber layer 9, stop ring 3, bead wire 8, and base 1 are all integrated, especially the stop ring 3 of the bias cord reinforcing layer 7.
When fixing to the stop ring 3, after covering the both stop rings 3 with the extra length at both ends,
A ring 8 of bead wire or the like adjacent to and having approximately the same diameter as the ring 8
The bias cord reinforcing layer 7 is attached to both ends of the bases 1 by wrapping the bias cord around the base and tightening the folded part with a wire such as synthetic fiber or steel wire, or by gluing the overlapped part. Both stop rings 3
It can be physically strongly adhered to.

The folded portion is further strengthened by overlapping at least a reinforcing layer 6 over the entire circumference.

As the bead wires for both rings 8 adjacent to both stop rings 3, a bundle of steel wires is usually used.

When adhering the cap 1 and the rubber layer, the metal material surface is subjected to adhesion treatment according to a conventional method, and then vulcanization adhesion is performed with unvulcanized rubber to integrate the material.

In addition, it is also possible to provide a concave groove 11 of seven shapes extending in a ring shape in the circumferential direction on the surface portion of the rubber layer of the tubular flexible portion 2, and the location of the concave groove 11 is selected as appropriate. .

Flexible expansion joints having the various configurations described above are buried in the ground or interposed as joints between water pipes placed in culverts and pipes of various diameters built on bridge piers, respectively, to reduce internal pressure, They are selected and used as appropriate depending on the magnitude of the external pressure, but it is preferable to use them as joints for exposed pipes where the external pressure is not high, for example.

Since this flexible expansion joint has the radial cord reinforcing layer 5 or the bias cord reinforcing layer 7 having a specific cord angle with the reinforcing layer 5 embedded in the tubular flexible portion 2, it has pressure resistance. There is no deformation due to expansion or compression, and the initial tube shape can be stably maintained for a long period of time.

In addition, in this flexible expansion joint, the large-diameter pipes on both sides move apart or become eccentric, causing the tubular flexible part 2 to stretch or bend.
Even if the rubber layer is elastic, it is highly adaptable and can easily follow the movement of the pipe, fully demonstrating its function as a flexible expansion joint.

In this case, the radial cord reinforcing layer 5, which is integrated with the rubber layer, is effective against breakage due to pressure, and the bias cord reinforcing layer 7 prevents abnormal elongation of the rubber layer in the longitudinal direction of the pipe, and prevents the flexible expansion joint from elongating. It plays a role in preventing deterioration and distortion.

Furthermore, when the tubular flexible portion 2 is subjected to stretching and bending, the greatest stress is applied to the connection portion with the cap, but the ends of the elastic bias cord reinforcing layer 7 are By physically fixing and integrating the connecting portion, the bonding force of the connecting portion is extremely large, and therefore, there will be no inconvenience such as separation of the cap 1 and the tubular flexible portion 2.

Next, the radial cord reinforcement layer 5 and the bias cord reinforcement layer 7
A comparative experiment was conducted to clarify the effects of each, and the results shown in the table below were obtained.

(4) Product: Joint pipe made of only rubber without reinforcing layers 5 and 7, (B) Product: Joint pipe with reinforcing layer 5 added to (A) product, (C)
Product: (Joint pipe with reinforcing layer 7 added to the entire circumference of product A, CD)
Product: (A) A joint pipe with both reinforcing layers 5 and 7 added to the entire circumference (corresponding to the joint pipe of the present invention). However, experimental example: A pipe with a diameter of 500 mm, and the reinforcing layer 5 is in the circumferential direction. (crossing angle 0) 4 briars, reinforcing layer 7 has 4 briars having cords with a bias angle of 45°,
The cord used is polyester/no end number 2 In the above experimental example, the product (4) expands like a rubber balloon and breaks the rubber because the reinforcing layers 5 and 7 are not present, and the product (B) does not have the reinforcing layer 7. As a result, the cord bent as the pressure increased and the rubber was cut.Product (C) did not deform, but the cord broke in the low pressure range.

From the above results, it is clear that the radial cord reinforcement layer 5 exhibits great resistance to pressure in the expansion direction, while the bias cord reinforcement layer 7 not only stabilizes the shape but also functions to strengthen the bond with the base 1. be.

Further, a comparative experiment was conducted to demonstrate that the bias cord reinforcing layer 7 has resistance to elongation deformation, and the results shown in the table below were obtained.

However, ◎Experimental example: 500 TrIn diameter pipe joints, product (4) is a product of the present invention having a radial cord reinforcing layer 5 and a bias cord reinforcing layer 7, and product (B) is a product of the present invention having a bias cord reinforcing layer 7. This is a comparison product that has the same structure as product (4) except that it does not.

◎Test method: One cap is fixed, the other cap is movable in the tube axis direction, and a water pressure of 5kp/cff is applied inside the joint pipe.
When 1 liter of water is sealed, the measurement gauge interval (interval between the insides of both caps) is 38011r! The amount of change in elongation of the IK was measured.

As is clear from the above results, the bias cord reinforcing layer 7
It has been clarified based on the experimental examples that the present invention exhibits sufficient characteristics to achieve the intended purpose, as shown in the above that the invention functions to control abnormal elongation deformation. In addition, when grooves are provided at predetermined locations on the outer periphery of the tubular flexible portion 2 as shown by dotted lines in FIG. In this case, the groove becomes a part that absorbs elastic deformation even more, so it plays a great role in preventing deterioration of the rubber layer, and prevents peeling at the boundary between the stop rings and the rubber layer. It is also possible to fully demonstrate the function of preventing.

[Effect of idea]

As detailed above, according to the present invention, the radial cord reinforcing layer 5 exhibits great resistance to pressure in the direction of expansion based on internal pressure and prevents breakage, while the bias cord reinforcing layer 7 undergoes elongation deformation exceeding the limit. As a result, the functions of both reinforcing layers 5 and 7 work together to prevent bending and stretching. It is possible to provide a pipe joint that is adaptable to shrinkage and eccentricity, and has excellent pressure resistance and durability.

[Brief explanation of the drawing]

Figure 1 is an axial sectional view of a conventional flexible expansion joint, Figure 2 is an axial sectional view of a flexible expansion joint according to the present invention, and Figure 3 is another flexible expansion joint according to the present invention. The axial longitudinal cross-sectional view of the main part of the expansion joint, FIGS. 4 and 5 are schematic diagrams showing each of the cord intersection angles of the reinforcing layer embedded in the tubular flexible part of the flexible expansion joint according to the present invention. be. 1', 1... Base, 2', 2... Tubular flexible part, 3'... Doubling tube, 3...
・Stop ring, 4.4'... Outer layer rubber, 5
...Radial cord reinforcement layer, 6...Folded part reinforcement layer, 6'...Steel ring, 7.
... Bias cord reinforcement layer, 8 ... Ring of bead wire, etc., 9 ... Inner layer comb, 10.
... Cover rubber, 11 ... Concave groove.

Claims (1)

[Claims for Utility Model Registration] 1. In a flexible expansion joint in which a pair of caps 1, 1 forming a joint portion and their connecting ends around which a stop ring 3 is provided are connected by a tubular flexible portion 2. , in a flexible expansion joint connected by a tubular flexible part 2, the tubular flexible part 2 is connected between one stop ring 3 of one connecting end and the opposite stop ring 3 of the other connecting end. At least one set of bias cord reinforcing layer 7 has cords of 10 to 4 in the circumferential direction.
The cord is buried between the inner rubber layer 9 and the outer rubber layer 4 over the entire circumference at least at the connecting end, making a crossing angle of 5°, and the end of the cord is inserted into the ring 8 which is in contact with both the stop rings 3, 3. At least one layer of radial cord reinforcing layer 5 is provided inside the bias cord reinforcing layer 7 so that the cords form an intersecting angle of 0 to 25 degrees with respect to the circumferential direction, and intersect the inner layer comb 9 with the outer layer. It is buried between the rubber 4 and the entire circumference,
A flexible expansion joint characterized in that its ends are brought into contact with the stop rings 3, 3. 2. The flexible expansion joint according to claim 1, wherein the bias cord reinforcing layer 7 is a pair of reinforcing layers separated in the axial direction.