JP2003314768A - Flexible joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible joint having enough flexibility to follow displacement of one end with respect to the other end, even if the length of the joint is small. <P>SOLUTION: This flexible joint J has a joint body 100 where reinforcing fabrics 101-105 are so embedded in a rubber tube along its circumferential direction as to form layers. At an end 111 of the joint body 100, the plurality of reinforcing fabrics 101-105 installed so as to be arranged in the lengthwise direction in the vertical section thereof form a single layer. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible joint having a joint body in which a reinforcing cloth is embedded in a tubular rubber so as to form a layer along the circumferential direction thereof.

[0002]

2. Description of the Related Art In piping for pressurizing cold water or hot water by a pump for air conditioning and the like, a flexible joint may be used to connect the pipes. Such a flexible joint has a joint body in which a reinforcing cloth is embedded in a tubular rubber along the circumferential direction so as to form a layer, and the joint cloth swells and deforms by resisting the pressure of fluid by the reinforcing cloth. It is supposed to never be done. On the other hand, a flexible joint is a thread that forms a reinforcing cloth so that when a pair of pipes, which are connected pipes, are relatively displaced due to an earthquake or the like, they flexibly stretch, bend, and deform following the displacement. Is optimized in the extending direction. That is, the flexible joint is required to have two different characteristics, that is, the rigidity that resists the pressure of the fluid flowing inside and the flexibility that follows the displacement with respect to the other end.

Japanese Unexamined Patent Publication (Kokai) No. 10-132155 discloses a steel coil reinforcement in which a cylindrical body wall formed of an inner and outer rubber layer, a steel reinforcing wire rod and a fiber reinforcing layer is bulged in the outer circumferential direction between the reinforcing wire rods. A flexible tube, in which a steel coil-like reinforcing wire having a constant pitch is arranged in the center of the cross section of the cylindrical body wall, and the hose is balanced with the pipe axis inside and outside the steel coil-like reinforcing wire. The inner and outer rubber layers made of rubber topping fiber cords laminated at a forming angle smaller than the angle is provided to axially compress the obtained laminated molded body, and the pitch of the steel coil-shaped reinforcing wire is applied from the center to both ends. According to such a structure, a seismic-resistant flexible pipe used as an underground buried pipe for a water conduit, particularly a water conduit for water and sewage, etc., particularly bending, expansion and contraction characteristics, is disclosed. Will be excellent It has been described as.

Japanese Unexamined Patent Publication No. 10-160058 discloses a hose in which a cylindrical body wall formed by providing a fiber reinforcing layer between inner and outer rubber layers is fixed to a flange, and the fiber reinforcing layer is rubber topping. It is disclosed that the molding angle of the fiber cord with respect to the tube axis is larger than the balance angle of the hose at both ends of the hose and smaller than the balance angle of the hose at the center. According to the document, it can be installed in the middle of an air conditioning sanitary pipeline such as a building or an outdoor panel tank to absorb the displacement in the pipe axis direction and the displacement in the pipe axis orthogonal direction at the time of an earthquake.

In Japanese Patent Laid-Open Publication No. 11-182764, a rigid rigid portion having a straight line in the outer circumference of the shaft is formed in the central portion of the pipe body and has a thickness smaller than that of the rigid portion. Disclosed is a high-pressure type flexible pipe joint in which a flexible portion having a corrugated outer circumference is extended to both ends of a rigid portion, and a flange for connection is provided at an end of each flexible portion. According to this configuration, it is described that bending can be prevented without impairing flexibility.

Japanese Unexamined Patent Publication No. 2001-50435 discloses a composite flexible tube having a step of forming a tubular body by spirally winding two or more kinds of materials having different rigidity into a core material while coextruding them in a strip shape. A manufacturing method is disclosed in which coextrusion is performed while changing the composition ratio of two or more materials. According to such a method, continuous manufacturing is possible, and partial composition changes It is described that partial reinforcement of the composite flexible tube can be increased and partial composition homogenization can be achieved.

[0007]

By the way, the problem of rigidity required for the flexible joint can be solved by increasing the reinforcing property of the joint body. On the other hand, the problem of flexibility required for the flexible joint does not directly give flexibility to the flexible joint, but the interval between the pair of pipes connected by the flexible joint is increased, that is, This can be solved by increasing the joint length.

The present invention has been made in view of the above points, and an object thereof is to provide a flexible joint having flexibility to follow displacement of one end with respect to the other end even if the joint length is short. To do.

[0009]

SUMMARY OF THE INVENTION According to the present invention, the end of a flexible joint is formed by arranging a plurality of reinforcing cloths in a longitudinal section so as to be aligned in the longitudinal direction to form one layer. The part is given flexibility.

Specifically, the present invention is premised on a flexible joint having a joint body in which a reinforcing cloth is embedded in layers in a tubular rubber along its circumferential direction, and the joint body is At its end, a plurality of reinforcing cloths arranged so as to be lined up in the longitudinal direction in a longitudinal section form one layer.

According to the above construction, a plurality of reinforcing cloths are arranged in the longitudinal direction at the end portion where the one end of the flexible joint is most deformed when the one end is displaced with respect to the other end. When the above displacement occurs, the ends can easily be stretched or bent without deformation when the above displacement occurs, so even if the joint length is short, The flexibility to follow the displacement with respect to the other end of is secured.

Here, "a plurality of reinforcing cloths arranged in the longitudinal direction in a longitudinal cross section" means, of course, a case where a plurality of reinforcing cloths are provided at the ends in the circumferential direction. It is meant to include the case where the strip-shaped reinforcing cloth is provided spirally in the circumferential direction.

In the present invention, it is preferable that a plurality of reinforcing cloths forming the one layer are arranged so as to be arranged at intervals in the longitudinal direction in the longitudinal section of the end portion.

According to the above construction, since the rubber is interposed between the reinforcing cloths and the deformation performance is high, the flexibility of the end portions is also increased accordingly.

In the present invention, the joint body may be such that a single reinforcing cloth forms one layer in a longitudinal section in a central portion sandwiched between both end portions.

According to the above construction, the single reinforcing cloth forms one layer in the central portion where the one end of the flexible joint is relatively less deformed when displaced from the other end. Thereby, the rigidity of the central portion becomes high and resists the pressure of the fluid, so that the bulging deformation of the joint body can be effectively suppressed.

In the present invention, the joint body may have a plurality of layers of reinforcing cloth having rubber layers interposed between the respective layers.

According to the above structure, the rigidity can be increased by increasing the number of layers of the reinforcing cloth, while the flexibility can be increased by decreasing the number of layers of the reinforcing cloth, and the rigidity and the rigidity can be improved. It can balance flexibility.

In this case, according to the present invention, the number of layers of the reinforcing cloth may be larger in the central portion sandwiched between the both end portions than in the above-mentioned end portion.

According to this structure, the flexibility is lower and the rigidity is higher in the central portion than in the end portions, and the difference in characteristics between the end portion and the central portion becomes remarkable, so that the other end of the flexible joint is not affected. It is possible to clearly separate the function of the end portion that deforms following the displacement with respect to the end and the function of the central portion that resists the pressure of the fluid and suppresses the bulging deformation of the joint body,
Each part can effectively perform its function.

[0021]

As described above, according to the present invention,
At the end, multiple reinforcing cloths arranged in the longitudinal direction in the longitudinal section form one layer, so even if the joint length is short, it follows the displacement of one connected pipe to the other connected pipe. Flexibility can be secured.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings.

1 and 2 show a flexible joint J according to an embodiment of the present invention.

This flexible joint J includes a joint body 100 made of a tubular rubber and a connecting portion 1 of each joint body 100.
A pair of metal flanges 200 externally fitted to 11;
Consists of.

In the joint body 100, the inner layer portion 106 facing the fluid passage hole is made of ethylene propylene rubber (EPM, EP).
The outer layer portion 107 is formed of a second rubber having a good workability such as natural rubber (NR), while the outer layer portion 107 is formed of a first rubber that is less affected by external factors such as DM). Further, in the joint body 100, the fluid circulation holes are formed with a uniform inner diameter. Further, the joint body 100 is formed such that the central portion 108 has the largest outer diameter and thus the thickest wall thickness, and the taper taper which is inclined outward at a large inclination angle is formed on both sides of the central portion 108. A portion 109 is formed, followed by the tapered portion 109, a first portion 110a having an outer diameter slightly smaller than that of the central portion 108, and subsequently, a tapered second portion 110b which is inclined outwardly at a gentle inclination angle and subsequently. And an end portion 110 including a third portion 110c having an outer diameter smaller than that of the first portion 110a is formed, and the third portion 110c of the end portion 110 is followed by a U-shaped groove 1
A connecting portion 111 having 11a is formed.

The joint body 100 has a reinforcing cloth 10 made of a woven fabric such as a polyester fiber along the circumferential direction thereof.
1 (101a, 101b), 102 (102a, 102)
b, 102c), 103 (103a, 103b, 103)
c), 104 (104a, 104b, 104c), 10
5 is embedded so as to form a layer, and further, a laminated structure composed of five layers of reinforcing cloths 101 to 105 in which a rubber layer is interposed between layers is configured. The blind fabric is subjected to an adhesive treatment (hereinafter referred to as "RFL treatment") in which it is immersed in a resorcin / formalin / latex (RFL) aqueous solution and then heated.

The innermost layer of the first reinforcing cloth 101 is provided in a range from slightly inside of the one connecting portion 111 to slightly inside of the other connecting portion 111, and one layer of reinforcing material corresponding to the central portion 108 is provided. The cloth 101a and one reinforcing cloth 101b corresponding to each end 110 are made up of a total of three pieces. Central part 108
The reinforcement cloth 101a corresponding to the above and the reinforcement cloth 101b corresponding to the end portion 110 are arranged at a position slightly outside the tapered portion 109 and spaced from each other. The reinforcing cloth 101 of the first layer is formed such that the warp threads of the interwoven fabric have an extending direction of about 70 ° with respect to the axial direction, and has a relatively low elastic modulus in the axial direction and is easily stretchable. Moreover, it has a relatively high elastic modulus in the circumferential direction and is difficult to stretch.

The layer of the second reinforcing cloth 102 which is the outer layer of the first layer is provided in the range from one connecting portion 111 to the other connecting portion 111, and one reinforcing cloth 102a corresponding to the central portion 108 is formed. Two reinforcing cloths 102 corresponding to each end 110
It consists of a total of 5 sheets, b and 102c. The reinforcing cloth 102a corresponding to the central portion 108 and the reinforcing cloth 102b corresponding to the inner side of the end portion 110 are arranged at a substantially central position of the first portion 110a of the end portion 110 with a space therebetween. The reinforcing cloth 102b corresponding to the inside of the end 110 and the reinforcing cloth 102c corresponding to the outside are the first portion 110 of the end 110.
They are arranged at intervals at the outer ends of a. The reinforcing cloth 102 of the second layer is also formed so that the warp threads of the interwoven fabric extend in an angle of about 70 ° with respect to the axial direction, and has a relatively low elastic modulus in the axial direction and is easily stretched. Moreover, it has a relatively high elastic modulus in the circumferential direction and is difficult to stretch.

The layer of the third reinforcing cloth 103, which is the outer layer of the second layer, extends from slightly inside the center of the second portion 110b of the one end 110 to slightly inside the center of the second portion 110b of the other end 110. 1 provided in the range and corresponding to the central portion 108
A total of five reinforcing cloths 103a and two reinforcing cloths 103b and 103c corresponding to the respective end portions 110 are formed. The reinforcing cloth 103 a corresponding to the central portion 108 and the reinforcing cloth 103 b corresponding to the inside of the end portion 110 are the first portion 1 of the end portion 110.
They are arranged at a position slightly outside the inner end of 10a and spaced from each other. The reinforcing cloth 103b corresponding to the inner side of the end 110 and the reinforcing cloth 103c corresponding to the outer side are
The ten first portions 110a are arranged at intervals slightly inward from the outer ends of the first portions 110a. Reinforcement cloth 1 for the third layer
No. 03 is formed such that the warp yarns of the blind fabric extend in the direction of about 45 ° with respect to the axial direction, and have the same elastic modulus and stretchability in the axial direction and the circumferential direction.

The layer of the fourth reinforcing cloth 104, which is the outer layer of the third layer, extends from the outer end of the first portion 110a of the one end 110 to the outer end of the first portion 110a of the other end 110. One piece of reinforcement cloth 1 provided corresponding to the central portion 108
04a and two reinforcing cloths 104 corresponding to each end 110
It consists of a total of 5 sheets, b and 104c. The reinforcing cloth 104a corresponding to the central portion 108 and the reinforcing cloth 104b corresponding to the inner side of the end portion 110 are arranged at a position of the tapered portion 109 with a space therebetween. The reinforcing cloth 104b corresponding to the inside of the end portion 110 and the reinforcing cloth 104c corresponding to the outside thereof are arranged at a position slightly outside the center of the first portion 110a of the end portion 110 with a space therebetween. The reinforcing cloth 104 of the fourth layer is formed such that the warp threads of the interwoven fabric extend in the direction of about 45 ° with respect to the axial direction, and the elastic modulus and the elasticity are equal in the axial direction and the circumferential direction. Have.

The layer of the fifth reinforcing cloth 105, which is the outer layer of the fourth layer, is provided in the range from one end to the other end of the central portion 108, and is composed of one sheet corresponding to the central portion 108. The fifth reinforcing cloth 105 is formed such that the warp threads of the interwoven fabric extend in the axial direction, has the highest elastic modulus in the axial direction, is extremely difficult to expand, and has the lowest elastic modulus in the circumferential direction. It is extremely easy to stretch.

Reinforcing cloths 101 to 105 are provided as an outer layer of the fifth layer.
The tightening cloth 112 for tightening the laminated structure of the above is in a range from approximately the center of the first portion 110a of the one end 110 to approximately the center of the first portion 110a of the other end 110,
It is provided along the circumferential direction. The tightening cloth 112 is RF
It is composed of a polyester woven fabric or the like that has been subjected to an adhesion treatment with L, and the warp of the woven fabric is formed so that the extending direction thereof forms an angle of 90 ° with the axial direction.
It has the lowest elastic modulus in the axial direction and is extremely stretchable, and has the highest elastic modulus in the circumferential direction and is extremely difficult to stretch.

As described above, in the joint body 100, the layers of the reinforcing cloths 102 to 104 at the end portions 110 are arranged in the longitudinal section at intervals in the longitudinal direction.
02b, 102c, 103b, ..., On the other hand, in the central portion 108, each layer of the reinforcing cloths 101, 102, ... Is formed by a single reinforcing cloth 101a, 102a ,. The central portion 108 has a larger number of layers of the reinforcing cloths 101 to 105 than the end portions 110.

On the outer side of the U-shaped groove 111a of the connecting portion 111 of the joint body 100, a metal ring member 115 having a substantially elliptical cross section and for retaining the shape of a flange 200 described later is embedded. In addition, the first end reinforcing cloth 113 extends outward from the slightly inner side of the outer end of the first portion 110a in the inner layer than the first layer reinforcing cloth 101 of the end portion 110, and extends toward the outer side. The first layer of reinforcing cloth 101 and the second layer of reinforcing cloth 10
It is provided along the circumferential direction so as to extend from the position of the outer end of the first-layer reinforcing cloth 101 between the two and the second end. The first end reinforcing cloth 113 is made of a double layer of interwoven fabrics such as polyester fibers which have been subjected to RFL adhesion treatment, and the warp of the interwoven fabrics extends in the direction of about 70 ° with respect to the axial direction. It is formed to make an angle. Further, the second end reinforcing cloth 114 extends outward from the outer end of the first layer reinforcing cloth 101 as a starting point, is folded back so as to wrap the ring material 115, and is again attached to the outer end of the first layer reinforcing cloth 101. It is provided along the circumferential direction so as to extend back. The second end reinforcing cloth 114 is RF
It is made of a woven fabric such as polyester fiber which has been subjected to an adhesion treatment with L, and is formed so that the extending direction of the warp threads of the woven fabric forms an angle of about 70 ° with respect to the axial direction.

The flange 200 is formed in an annular shape having a substantially rectangular cross section, and is fitted into the U-shaped groove 111a of the connecting portion 111 of the joint body 100. Also, the flange 20
A hole 201 for attachment is formed at 0.

The flexible joint J having such a structure is arranged between a pair of connected pipes to form a pipe.

Next, a method of manufacturing the flexible joint J will be described.

First, an unvulcanized inner rubber tube obtained by extruding the first rubber is externally fitted to the mandrel. This inner rubber tube becomes the inner layer portion 106.

Next, the unvulcanized inner rubber tube externally fitted on the mandrel is heated and pressurized to be in a semi-vulcanized state.

Next, the connecting portion 111 of the inner tube
The first end reinforcing cloth 113 is wound so that the first end reinforcing cloth 113 has a portion protruding outward from the end. The first end reinforcing cloth 113 used here has a warp extending in the axial direction 70
RF woven fabric that is formed to form an angle of around
After the L treatment is performed to form two sheets, the second rubber is topped on both sides with a calendar roll.

Then, a first unvulcanized rubber sheet made of a relatively thin second rubber is wound around the first end reinforcing cloth 113 and the inner tube. At this time, if the first rubber and the second rubber do not fit well, an adhesive such as rubber glue may be applied to the surface of the inner tube.

Then, the first unvulcanized rubber sheet is firstly placed on the first unvulcanized rubber sheet.
The reinforcing cloth 101, which is a layer, is wrapped around the reinforcing cloth 1.
01 is cut into a band shape in the circumferential direction at a predetermined position in the axial direction and divided into three pieces spaced apart from each other. The reinforcing cloth 101 used here is one obtained by RFL-treating a blind fabric formed so that the warp threads extend in an angle of about 70 ° with respect to the axial direction, and then second rubber is topped on both sides with a calendar roll. is there.

Then, the second end reinforcing cloth 114 is wound so that one end is along the outer end of the first layer reinforcing cloth 101 and the second end reinforcing cloth 114 has a portion protruding outward from the end of the inner tube. The second end reinforcing cloth 114 used here is a comb-shaped woven fabric formed so that the warp threads extend in the axial direction.
After the FL treatment, the second rubber was topped on both sides with a calendar roll.

Next, after the flange 200 is passed through the mandrel, the ring material 115 is externally fitted to the first and second end reinforcing cloths 113 and 114 at the ends of the inner tube.

Then, the first and second end reinforcing cloths 113,
After wrapping the ring material 115 with 114 so that they are folded back inward, the flange 20 that has been previously passed through the mandrel
0 is moved to the outside and is fitted onto the folded first and second end portion reinforcing cloths 113 and 114.

Next, a second unvulcanized rubber sheet made of a relatively thick second rubber is wound around the first layer of reinforcing cloth 101. This unvulcanized rubber sheet serves as an outer rubber layer of the reinforcing cloth 101 as the first layer.

Then, a second unvulcanized rubber sheet is placed on the second unvulcanized rubber sheet.
The reinforcing cloth 102 is wrapped around one layer of the reinforcing cloth 102, and
02 is cut in a band shape in the circumferential direction at a predetermined position in the axial direction and divided into five pieces spaced apart from each other. The reinforcing cloth 102 used here is the one in which the second rubber is topped on both sides with a calendar roll after RFL processing of the interwoven fabric formed such that the warp extending direction forms an angle of about 70 ° with respect to the axial direction. is there.

Then, a third unvulcanized rubber sheet, which is the same as the second unvulcanized rubber sheet and is relatively thick, is wound around the second layer of reinforcing cloth 102. This unvulcanized rubber sheet serves as an outer rubber layer of the second-layer reinforcing cloth 102.

Next, the third unvulcanized rubber sheet is placed on the third sheet.
The reinforcing cloth 103 is wound around one layer of the reinforcing cloth 103,
03 is cut in a band shape in the circumferential direction at a predetermined position in the axial direction and divided into five pieces spaced apart from each other. The reinforcing cloth 103 used here is the one in which the second rubber is topped on both sides with a calendar roll after RFL processing of the interwoven fabric formed such that the warp extending direction forms an angle of about 45 ° with respect to the axial direction. is there.

Then, a relatively thick fourth unvulcanized rubber sheet, which is the same as the second unvulcanized rubber sheet, is wound around the third layer of reinforcing cloth 103. This unvulcanized rubber sheet serves as an outer rubber layer of the reinforcing cloth 103 of the third layer.

Then, the fourth unvulcanized rubber sheet is placed on the fourth sheet.
The reinforcing cloth 104 is wound around one layer of the reinforcing cloth 104,
04 is cut in a band shape in the circumferential direction at a predetermined position in the axial direction and divided into five pieces spaced apart from each other. The reinforcing cloth 104 used here is one in which the second rubber is topped on both sides with a calendar roll after RFL processing of the interwoven fabric formed so that the warp extending direction forms an angle of about 45 ° with respect to the axial direction. is there.

Then, a fifth relatively thick unvulcanized rubber sheet, which is the same as the second unvulcanized rubber sheet, is wound around the center of the fourth layer of reinforcing cloth 104. This unvulcanized rubber sheet serves as an outer rubber layer of the fourth layer reinforcing cloth 104.

Then, the fifth unvulcanized rubber sheet is placed on the fifth sheet.
A layer of reinforcing cloth 105 is wrapped around. The reinforcing cloth 105 used here is the one in which the second rubber is topped on both surfaces with a calendar roll after RFL processing of the interwoven fabric formed so that the warp yarns extend in the axial direction.

Then, the tightening cloth 112 is wrapped around a part of the fourth layer reinforcing cloth 104 and the fifth layer reinforcing cloth 105.

Then, this is heated and pressed to vulcanize the unvulcanized rubber, and at the same time, the rubber and each reinforcing cloth 10
The flexible joint J is manufactured by integrating 1 to 105.

According to the flexible joint J having the above-mentioned structure, the plurality of reinforcing cloths 1 are formed in the longitudinal section at the end portion 110 where the largest deformation occurs when one end of the flexible joint J is displaced with respect to the other end.
02b, 102c, ... Form a single layer arranged so as to be aligned in the longitudinal direction, and are adjacent to each other.
02b, 102c, ... Are provided at intervals, and rubber is interposed between the reinforcing cloths 102b, 102c, ..., so that the deformation performance is high. As shown in (b), the reinforcing cloth 102b, 1
Since the end portion 110 can be easily stretched or bent without being constrained between the two 02c, ..., Even if the joint length is short, it is possible to secure the flexibility to follow the displacement from one end to the other end. it can.

Further, the single reinforcing cloth 101a, 102a, ... Form one layer at the central portion 108, which is relatively less deformed when one end of the flexible joint J is displaced with respect to the other end. As a result, the rigidity of the central portion 108 becomes high and resists the pressure of the fluid, so that the bulging deformation of the joint body 100 can be effectively suppressed.

Furthermore, the central portion 108 has a larger number of layers of the reinforcing cloths 101 to 105 than the end portion 110, which makes the central portion 108 less flexible and more rigid than the end portion 110. Since the difference between the characteristics of the end portion 110 and the central portion 108 becomes remarkable, the function of the end portion 110 of deforming following the displacement of one end of the flexible joint J with respect to the other end, and resisting the pressure of the fluid. The function of the central portion 108 to suppress the bulging deformation of the joint body 100 is clearly separated, and each function can be effectively exhibited. That is, the joint body 100 has a plurality of layers of reinforcing cloths 101 to 105 with rubber layers interposed between the layers,
While the rigidity can be increased by increasing the number of layers of the reinforcing cloths 101 to 105, the reinforcing cloths 101 to 105
The flexibility can be increased by reducing the number of layers of the, so that the rigidity and the flexibility can be balanced.

[Brief description of drawings]

FIG. 1 is a side view of a flexible joint according to an embodiment of the present invention.

FIG. 2 is a sectional view of an end portion of the flexible joint according to the embodiment of the present invention.

FIG. 3 is an explanatory view showing a cross section of an end portion before and after deformation of the flexible joint according to the embodiment of the present invention.

[Explanation of symbols]

J Flexible joint 100 fitting body 101-105 Reinforcing cloth 106 inner layer 107 outer layer 108 central part 109 taper part 110 edge 110a first part 110b second part 110c Third part 111 Connection 111a U-shaped groove 112 tightening cloth 113 First end reinforcement cloth 114 Second end reinforcement cloth 115 Ring material 200 flange 201 holes

Claims (5)

[Claims] 1. A flexible joint having a joint body embedded in a tubular rubber so as to form a layer of reinforcing cloth in a circumferential direction thereof, wherein the joint body has a longitudinal section in a longitudinal section at its end. A flexible joint characterized in that one layer is formed by a plurality of reinforcing cloths arranged so as to be aligned in the direction. 2. The flexible joint according to claim 1, wherein the plurality of reinforcing cloths forming the one layer are arranged so as to be spaced apart from each other in a longitudinal direction in a longitudinal cross section of the end portion. A flexible joint characterized by being installed. 3. The flexible joint according to claim 1 or 2, wherein in the joint body, a single reinforcing cloth forms one layer in a longitudinal section in a central portion sandwiched between both end portions. A flexible joint characterized by the above. 4. The flexible joint according to claim 1, wherein the joint body has a plurality of layers of reinforcing cloth with a rubber layer interposed between the layers. Flexible joint. 5. The flexible joint according to claim 4, wherein the central portion sandwiched between both end portions has more layers of reinforcing cloth than the end portions.