CN101398114A - Flexible pipe joint - Google Patents

Abstract

The present invention provides a flexible pipe joint capable of reducing the diameter. A retaining ring (3) is provided in the through hole (2a) of the joint main body (2) so as to be immovably engaged with the metal pipe (Fa) of the hose (F). On one end portion of the inner peripheral surface of the through hole (2a) inserted into the flexible pipe (F), an internal thread portion (2g) is formed. The internal thread portion (2g) is threaded with the external thread portion (4d) of the threaded member (4). Cooperate. The front end face of the threaded part (4) pushes and contacts the retaining ring (3).

Description

Couplings for flexible pipe

technical field

The present invention relates to a hose joint used for connecting a flexible pipe (hereinafter simply referred to as a hose) to a gas pipe, a water pipe, or the like.

Background technique

Generally, a hose joint includes a joint main body, a snap ring (engagement member), and a pocket nut (thread member) as described in Patent Document 1 below. A through hole penetrating from one end surface to the other end surface is formed inside the joint main body, and an annular contact surface is formed on the inner peripheral surface of the through hole. The hose is inserted from the opening at one end of the through hole until it abuts against the contact surface. A pocket nut is screwed on the outer peripheral surface of one end of the joint main body. The pocket nut contacts the retaining ring. Therefore, when the bag nut is tightened, the retaining ring moves to approach the contact surface, pushing the front end face of the hose against the contact surface. Thus, the hose is connected to the joint main body. Needless to say, the other end of the joint main body is connected to a gas pipe or the like. As a result, the hose is connected to a gas pipe or the like via a joint.

Patent Document 1: Japanese Utility Model Application Publication No. 110788, Showa 63

In the aforementioned conventional hose joint, the retaining ring is inserted into the inside of the one end portion of the joint body, and the screw member is screwed to the outer periphery of the one end portion of the joint body. That is, the three components of the retaining ring, the joint main body and the pocket nut are sequentially arranged from the inner side to the outer side. For this reason, there is a problem that the diameter of the joint increases.

Contents of the invention

In order to solve the above-mentioned technical problems, the present invention provides a joint for flexible pipes, which has: a joint main body, which forms a through hole into which a flexible pipe with a metal pipe formed in a corrugated outer peripheral surface is inserted from an opening at one end; The inner peripheral surface of the through hole is formed on the contact surface pressed by the front end surface of the metal pipe; the engaging member is inserted into the through hole so as to be movable from the opening at one end thereof, and is connected to the outer peripheral surface of the metal pipe. engages immovably along its length; a threaded part, which is threadedly engaged with the fitting body, passes through the flexible tube, and once tightened, the threaded part pushes against the An engaging member, and furthermore, the engaging member presses the metal pipe so that the front end thereof presses the contact surface in a sealed state, wherein an internal thread is formed at one end of the inner peripheral surface of the through hole part, an external thread part screwed with the internal thread part is formed at the front end part of the outer peripheral surface of the screw part, and the length of the engaging part is set to be longer than that of the joint main body opened from one end part of the through hole. The distance from the end surface of the screw member to the contact surface is short, and the front end surface of the threaded member abuts against the rear end surface of the engaging member.

At this time, it is preferable that an annular sealing member is provided on the contact surface, and the front end surface of the metal pipe presses into contact with the contact surface via the sealing member.

Preferably, on the portion of the threaded member protruding outward from the through hole, a gas-permeable member made of a material that prevents liquid from permeating and allows gas to permeate, with its inner and outer ends facing the inner and outer spaces of the threaded member status settings.

Preferably, a portion of the inner peripheral surface of the through hole near the contact surface is formed so as to approach the axis of the through hole as it approaches the contact surface from the one end opening side of the through hole. The inclined inclined surface by which the engaging member moves so as to approach the outer peripheral surface of the metal pipe as it moves toward the contact surface side.

It is preferable that the flexible pipe further has a covering pipe provided on the outside of the metal pipe, and a waterproof member is provided on the inner peripheral surface of the threaded member, which has a predetermined frictional resistance and is in contact with the outer periphery of the covering pipe. surface contact to prevent liquid from intruding between the inner peripheral surface of the threaded part and the outer peripheral surface of the cladding tube.

Preferably, the engaging member is rotatably mounted on the outer peripheral surface of the metal pipe, on at least one of the front end surface of the threaded member and the rear end surface of the engaging member that are in contact with each other, in order to make the gap between The frictional resistance is reduced, and a coating layer made of a material having a coefficient of friction smaller than that of the material constituting the screw member and the material constituting the engaging member is provided.

According to the present invention having the above-mentioned characteristic configuration, the engaging member and the screw member are arranged in the longitudinal direction of the through hole, but are not arranged in the inner-outer direction. That is to say, the joint main body, the engaging part and the threaded part are only arranged side by side in the inner and outer direction, and the three are not arranged side by side in the inner and outer direction. Therefore, a reduced-diameter joint can be obtained.

Description of drawings

Fig. 1 is a sectional view showing a first embodiment of the present invention.

Fig. 2 is a sectional view showing the same embodiment in a state where a hose is connected.

Fig. 3 is a plan view showing a retaining ring used in the same embodiment.

Fig. 4 is a cross-sectional view along line X-X in Fig. 3 .

Fig. 5 is a cross-sectional view along line Y-Y in Fig. 3 .

Fig. 6 is a sectional view showing a state in which a hose is inserted into the screw member of the same embodiment.

Fig. 7 is a view showing a state where a metal tube of a hose is inserted into the retaining ring of the same embodiment.

Fig. 8 is a view showing a state in which a metal pipe, a retaining ring, and a screw member are inserted into the joint main body of the same embodiment.

Fig. 9 is a view showing the state in the middle of connecting the metal pipe and the joint main body of the same embodiment.

Fig. 10 is a sectional view showing a second embodiment of the present invention in a state where a hose is connected.

Fig. 11 is a plan view showing a retaining ring used in the same embodiment.

Fig. 12 is a cross-sectional view along line X-X in Fig. 12 .

Fig. 13 is a cross-sectional view showing a state in which a hose is connected according to a third embodiment of the present invention.

Fig. 14 is a plan view showing a retaining ring used in the same embodiment.

Fig. 15 is a sectional view along line X-X in Fig. 14 .

Fig. 16 is a sectional view showing a fourth embodiment of the present invention in a state where a hose is connected.

Fig. 17 is a plan view showing a retaining ring used in the same embodiment.

Fig. 18 is a sectional view along line X-X in Fig. 17 .

Explanation of reference signs

1 Hose Coupling 2 Coupling Body 2a Through Hole 2f Contact Surface

2g Internal thread part 2h Cone surface (inclined surface) 3 Retaining ring (engagement part)

3A retaining ring (snap part) 3B retaining ring (snap part)

3C retaining ring (clamping part) 4 threaded part 4d external threaded part

5 gasket (sealing part) 7 sealing part (waterproof part) 8 breathable part

Detailed ways

Next, preferred embodiments for carrying out the present invention will be described with reference to the drawings.

FIG. 1 shows a joint 1 for a hose according to the present invention, and FIG. 2 shows a state in which the joint 1 and a hose F are connected. First, the hose F will be described. The hose Fa includes a metal tube Fa and a cladding tube Fb as known. The metal pipe Fa and the covering pipe Fb have bendable flexibility. The metal pipe Fa is alternately formed with peaks and valleys along the length direction of the metal pipe Fa, and both the peaks and the valleys form a slightly arc shape. Accordingly, the outer peripheral surface of the metal pipe Fa becomes wavy. The cover pipe Fb is composed of a resin pipe having a constant inner and outer diameter, and the metal pipe Fa is inserted therein. The inner diameter of the cladding tube Fb is slightly smaller than the maximum diameter of the peak of the metal tube Fa. Therefore, the inner peripheral surface of the cladding tube Fb is pressed into contact with the outer peripheral surface of the peak.

The joint 1 is a member for connecting the above-mentioned hose F to a gas pipe or a gas appliance, and includes a joint main body 2 , a snap ring (engagement member) 3 , and a screw member 4 . In addition, when the hose F is used as, for example, a water supply and drainage pipe, the joint 1 is used to connect the hose F to a water instrument.

The joint main body 2 has formed therein a through-hole 2a penetrating from the right end surface (one end surface) to the left end surface (the other end surface). The through-hole 2a is constituted by a large-diameter hole portion 2b on one end side and a small-diameter hole portion 2c on the other end side. Between the large-diameter hole portion 2b and the small-diameter hole portion 2c, an annular stepped surface 2d facing the right is formed. On this stepped surface 2d, a concave portion 2e extending annularly around the axis line of the through hole 2a is formed. A ring-shaped gasket (sealing member) 5 made of hard rubber or other resin is attached to the concave portion 2c. The gasket 5 is pressed against the bottom surface of the concave portion 2e, and the bottom surface of the concave portion 2e becomes the contact surface 2f. The contact surface 2f is formed in a ring shape centering on the axis line of the through hole 2a. The inner diameter of the gasket 5 is set substantially the same as the inner diameter of the small-diameter hole portion 2c. Therefore, the inner peripheral surface of the gasket 5 is located on the extension of the inner peripheral surface of the small-diameter portion 2c.

An external thread portion 2g having a constant inner diameter is formed at an end portion on the opening side of the large-diameter hole 2b. In addition, a tapered surface (inclined surface) 2h whose diameter becomes smaller as it gets closer to the stepped surface 2d is formed on a portion of the inner peripheral surface of the large-diameter hole portion 2b adjacent to the stepped portion 2d. The tapered surface 2h is formed of a conical surface whose axis line coincides with the axis line of the through hole 2a. The tapered surface 2h may be replaced by two inclined surfaces arranged away from each other by 180° in the circumferential direction of the through hole 2a and inclined closer to each other as they approach the step surface 2d. On the other end portion of the outer peripheral surface of the joint main body 2, a tapered male thread portion 2i is formed. On this tapered external thread portion 2i, a gas pipe or a gas appliance is screw-fitted and fixed. The tapered external thread 2i can be replaced by other connection methods, for example, a straight external thread can be formed, and a connecting nut can be rotatably provided at the other end of the joint body 2 .

The stop ring 3 is constituted by a circular metal ring, and its length is set to be shorter than the length of the large-diameter hole portion 2b. Therefore, the entire stop ring 3 can be inserted into the large-diameter hole portion 2b. As shown in FIGS. 3 to 5 , on one side of the retaining ring 3 , a split slit 3 a is formed across the side. On the inner peripheral surface of the other side facing the axis of the retaining ring 3 across the slit 3a, a groove 3b is formed that traverses the other side in the axial direction of the retaining ring 3. As shown in FIG. A hinge portion 3c is formed between the groove 3b and the outer peripheral surface of the snap ring 3 . By deforming the hinge portion 3c, the width of the slit 3a can be varied in width. And, when expanding the width of the slit 3a, as shown in FIG. 7, the metal pipe Fa can be moved in its diameter direction and inserted into the stop ring 3 from the slit 3a. When the width of the slit 3a is restored to the original width, the outer diameter of the retaining ring 3 is slightly smaller than the inner diameter of the internal thread portion 2g (=the maximum diameter of the tapered surface 2h), and becomes larger than the minimum diameter of the tapered surface 2h. Therefore, the retaining ring 3 can be inserted into the large-diameter hole 2b through its right end opening (one end opening), and when inserted to a proper position, the left end of the retaining ring 3 touches the tapered surface 2h. Thereafter, when the retaining ring 3 is further inserted, the diameter of the retaining ring 3 decreases along with the tapered surface 2h.

On one end and the other end of the inner peripheral surface of the retaining ring 3, protrusions 3d, 3d protruding radially inward of the retaining ring 3 are formed. The length of the protruding portion 3d is slightly shorter than the radius difference between the peak portion and the valley portion. When the front end portion of the protruding portion 3d is in contact with the outer peripheral surface near the deepest portion of the valley portion of the metal pipe Fa, the retaining ring 3 cannot move toward the metal pipe Fa. Move in the length direction. That is, the retaining ring 3 is engaged with the outer periphery of the metal pipe Fa so as to be immovable in the longitudinal direction thereof. The part between the protruding parts 3d and 3d on the inner peripheral surface of the retaining ring 3 is formed in a wave shape so that when the protruding part 3d is in contact with the valley part, the crest part is only separated from the metal pipe Fa in the radial direction outward. In addition, the retaining ring 3 is engaged from the front end surface of the metal pipe Fa at a position rearward to the left and right of the 2-3 crest.

A coating layer (not shown) is provided on the rear end surface of the retaining ring 3 and at least the inner peripheral portions of the protruding portions 3d, 3d that are in contact with the metal pipe Fa. The coating layer is made of a material having a friction coefficient smaller than that of the material constituting the retaining ring 3 and the material constituting the screw member 4, for example, molybdenum disulfide (MOS ₂ ). Its thickness is set to an appropriate thickness according to the material constituting the coating layer. For example, in the case of molybdenum disulfide, it is about 5 to 20 μm.

The screw member 4 is composed of a small-diameter portion 4a on the front end (left end side) and a large-diameter portion 4b on the rear end side (right end side). Inside the screw member 4, a through hole 4c penetrating from the left end surface (front end surface) to the right end surface is formed. The through-hole 4c is arranged such that its axis line coincides with the axes of the small-diameter portion 4a and the large-diameter portion 4b. The inner diameter of the through hole 4c is slightly larger than the outer diameter of the covering pipe Fb. Therefore, the covering tube can be inserted into the through hole 4c.

On the outer peripheral surface of the small-diameter portion 4a, an external thread portion 4d is formed. The external thread portion 4d is screwed to the internal thread portion 2g of the joint main body 2 . Since the external threaded part 4d is screwed into the internal threaded part 2g, when the threaded part 4 is fastened, the front end surface (left end surface) of the threaded part 4 touches the rear end surface (right end surface) of the retaining ring 3, so that the retaining ring 3 faces the contact surface 2f. Move sideways. In addition, a sealing member 6 such as an O-ring is hermetically sealed between the outer peripheral surface of the small-diameter portion 4 a and the inner peripheral surface of the large-diameter hole portion 2 b.

A mounting recess 4e extending annularly in the circumferential direction is formed at a portion corresponding to the large-diameter portion 4b on the inner peripheral surface of the through hole 4c. A ring-shaped sealing member (waterproof member) 7 is attached to the mounting recess 4e. The sealing member 7 is made of rubber or other elastic materials, and is mounted so that the mounting recess 4e cannot move in the axial direction. An annular protruding portion 7 a protruding radially inward is formed in an intermediate portion of the inner peripheral surface of the sealing member 7 . The inner diameter of the protruding portion 7a is smaller than the outer diameter of the covering tube Fb. Therefore, when the coating tube Fb is inserted into the through hole 4c, the tip portion (inner peripheral portion) of the protruding portion 7a is pressed against the outer peripheral surface of the coating tube Fb in an annular shape. Thereby, the inner peripheral surface of the through-hole 4c and the outer peripheral surface of the covering pipe Fb are airtightly sealed. In addition, when the protruding portion 7a is pressed into contact with the covering pipe Fb, frictional resistance is generated between them. The magnitude of this frictional resistance is set to prevent the screw member 4 from moving in the longitudinal direction of the covering pipe Fb even when the covering pipe Fb is inclined at a predetermined angle (for example, 45°) or less with respect to the horizontal line. The magnitude of the frictional resistance can also be set so as to prevent the movement of the screw member 4 even when the cover pipe Fb is oriented in the vertical direction.

A hole 4f penetrating from the outer peripheral surface to the inner peripheral surface of the through hole 4c is formed in the end portion of the large diameter portion 4b on the side of the small diameter portion 4a. In this hole 4f, the ventilation member 8 is inserted and fixed. The air-permeable member 8 is made of a material (continuous porous body) formed by compacting tetrafluoroethylene resin powder, such as polyethylene, polypropylene or A material formed of thermoplastic resin powder such as polymethacrylate and formed of a porous body with continuous pores has an outer end face open to the outside of the screw member 4, and an inner end face open to the inner space of the screw member 4, thereby The inner space is opened to the inner side (left side) than the sealing member 7 .

When connecting the hose F to a gas appliance such as a gas pipe using the joint 1 of the above configuration, screw the gas pipe or other gas appliances to the tapered external thread portion 2i, and insert the front end of the hose F into the large-diameter hole. part 2b and connect. As a result, the hose is connected to the gas appliance through the joint.

When connecting the hose F to the joint 1, as shown in FIG. 6, first, cut off the front end of the cladding tube Fb so that only a predetermined number of peaks (for example, 4-5 peaks) are exposed from the front end of the metal tube Fa. Next, the front end of the hose F and the screw member 4 are relatively moved toward the axial direction of the screw member 4, and the front end of the covering pipe Fb is passed through the through hole 4c. After that, as shown in FIG. 7, the gap 3a of the retaining ring 3 is expanded. Then, by relatively moving the retaining ring 3 and the front end portion of the hose F in the radial direction of the hose F, the metal pipe Fa is inserted through the slit 3 a widening in the retaining ring 3 . Thereafter, the retaining ring 3 returns to its original state, and the retaining ring 3 is engaged with the metal pipe Fa so that it cannot move in the longitudinal direction. At this time, the retaining ring 3 is engaged with only 2-3 crests from the front end of the metal pipe Fa to the rear. Then, the threaded member 4 is moved toward the front end side of the hose F against the frictional resistance between the sealing member 7 and the covering pipe Fb, so that the front end surface of the threaded member 4 contacts or substantially contacts the rear end surface of the retaining ring 3 .

Next, the metal pipe Fa, the snap ring 3 and the screw member 4 are inserted through the opening of the large-diameter hole 2b. After the front end portion of the male thread portion 4d of the screw member 4 collides with the end portion on the opening side of the female thread portion 2g, the screw member 4 is screwed into the large-diameter hole portion 2b while being turned. Then, the front end surface of the screw member 4 hits the rear end surface of the stop ring 3 and moves forward (leftward), and the hose F is advanced again. When the hose F advances to a predetermined position, the front end surface of the metal pipe Fa collides with the contact surface 2 f via the gasket 5 . Therefore, when the retaining ring 3 advances further, the portion between the front end surface of the metal pipe Fa and the retaining ring 3 is crushed, and at the same time, the front end of the metal pipe Fa is forcibly pressed by the washer 5 . When the stop ring 3 advances to a predetermined position, the stop ring 3 collides with the tapered surface 2h. Then, the retaining ring 3 decreases in diameter as it advances, and its protrusion 3 d contacts the valley of the metal pipe Fa on the smaller diameter side. As a result, the snap ring 3 is more firmly engaged by the metal pipe Fa.

Here, when the screw member 4 is rotated, due to the frictional resistance generated between the front end surface of the screw member 4 colliding with each other and the rear end surface of the retainer ring 3, the retainer ring 3 rotates together with the thread member 4, and passes through the retainer ring 3 again. When the front end surface of the metal pipe Fa is rotated, the gasket 5 is damaged due to the front end surface of the metal pipe Fa, and gas may leak from between the front end surface of the metal pipe Fa and the gasket 5 . However, in this joint 1 , since the back end surface of the retaining ring 3 is coated with a material having a low coefficient of friction, the retaining ring 3 does not rotate together with the screw member 4 . Even if the retaining ring 3 rotates together with the screw member 4, since the coating layer is also provided on the inner peripheral portion of the protruding portion 3d, the front end portion of the metal pipe Fa does not rotate due to the retaining ring 3. Therefore, the gasket 5 is not damaged. Therefore, gas leakage between the front end portion of the metal pipe Fa and the gasket 5 can be reliably prevented.

Screw in the threaded part 4 again to advance the retaining ring 3, so that the 2-3 peaks on the front end side of the metal pipe Fa, that is to say, the front end of the metal pipe Fa located between the retaining ring 3 and the washer 5 is completely crushed. , so that the threaded part 4 will not be screwed in excessively. In this state, the front end portion of the metal pipe Fa and the gasket 5 are airtightly sealed, and the inside of the metal pipe Fa communicates with the inside of the left through hole 2 a through the stop ring 3 . Thus, the connection of the hose F to the joint main body 2 is completed.

In the state where the connection is completed, as shown in FIG. 2 , the retaining ring 3 and the screw member 4 are aligned in the axial direction of the through hole 2 a, not in the radial direction (inward and outward directions). That is, the joint main body 2 , the retaining ring 3 and the threaded member 4 are aligned only in the radial direction, and the joint main body 2 , the retaining ring 3 and the threaded member 4 are not aligned in the radial direction. Therefore, the outer diameter of the joint 1 can be reduced.

In addition, because the gas does not leak from between the front end of the metal pipe Fa and the gasket 5, even if the gas leaks, the sealing member 6 can prevent the gas from leaking from the inner peripheral surface of the large-diameter hole portion 2b and the outer peripheral surface of the small-diameter portion 4a. In addition, the sealing member 7 can also prevent gas from leaking between the outer peripheral surface of the coating pipe Fbd and the inner peripheral surface of the threaded member 4. And, when the gas leaks, since the gas leaks outside through the air-permeable member 8, by detecting the gas leaked from the air-permeable member 8 to the outside, accidents caused by the gas leakage can be prevented before they happen.

Next, other embodiments of the present invention will be described. In the following embodiments, only configurations different from those of the above-mentioned embodiments will be described, and the same symbols will be used for the same parts, and descriptions thereof will be omitted.

10 to 12 show a second embodiment of the present invention. In the hose joint 1A of this embodiment, the retaining ring 3A is used instead of the retaining ring 3 . The retaining ring 3A is shorter in length (the length in the axial direction of the through hole 2 a ) than the retaining ring 3 . For this reason, only one protruding portion 3d is formed on the retaining ring 3A, and the protruding portion 3d is arranged at the center portion in the longitudinal direction of the inner peripheral surface of the retaining ring 3A. In addition, the protruding portion 3 d has a rectangular cross-sectional shape except for a tip portion (end portion on the inner peripheral side), and the tip portion is formed in a substantially semicircular shape. Moreover, since the front-end|tip part of the protrusion part 3b engages with the valley part of the outer peripheral surface of the metal pipe Fa, the stop ring 3A engages with the metal pipe Fa so that it cannot move in the longitudinal direction.

13 to 15 show a third embodiment of the present invention. In the hose joint 1B of this embodiment, a snap ring 3B is used. The stop ring 3B has a shape in which two of the above-mentioned stop rings 3A are aligned in the longitudinal direction and are continuous. Therefore, on the inner peripheral surface of the retaining ring 3B, two protrusions 3d, 3d are formed. The distance between the two protrusions 3d, 3d is set to be the same as the distance between the valleys of the metal pipe Fa. Therefore, the two protrusions 3d, 3d are respectively engaged with two adjacent valleys, whereby the stop ring 3B is engaged with the metal pipe Fa so as to be immovable in the longitudinal direction thereof. The shape of the space between the two protruding parts 3d, 3d is approximately rectangular with respect to the shape of the space of the retaining ring 3 which is similar to the shape of the peak of the metal pipe Fa.

16 to 18 show a fourth embodiment of the present invention. In the hose joint 1C of this embodiment, the stop ring 3C is used. In this retaining ring 3C, the protruding portion 3d is arranged at the end portion on the contact surface 2f side. As a result, the cross-sectional shape of the retaining ring 3C is substantially L-shaped.

In addition, this invention is not limited to the said Example, It can change suitably in the range which does not deviate from the summary.

For example, in the above-mentioned embodiment, the front end surface of the metal pipe Fa is pressed to the contact surface 2f through the gasket 5, but it may be directly pressed to the contact surface.

In addition, in the above-described embodiment, the ring-shaped retaining rings 3 to 3C are used, but the retaining rings 3 to 3C may be configured in a plurality of sectors separated from each other in the circumferential direction.

In addition, in the above-mentioned embodiment, in order to prevent the retaining ring 3-3C from rotating together with the threaded part 4, a coating layer is provided on the rear end surface of the retaining ring 3-3C in contact with the threaded part 4, but it is also possible to coat the threaded part 4 A coating layer is provided on the front end surface in contact with the retaining ring 3, and a coating layer can also be provided on both.

Claims (6)

1. A joint for flexible pipes, comprising: a joint main body, which forms a through hole into which a flexible pipe having a corrugated metal pipe on the outer peripheral surface is inserted from an opening at one end, and on the inner peripheral surface of the through hole. The contact surface pushed and contacted by the front end surface of the metal pipe; the engaging member, which is inserted into the through hole so as to be movable from the opening at one end thereof, and engages with the outer peripheral surface of the metal pipe so as not to move in the longitudinal direction thereof. Snapping; threaded part, which is threadedly fitted with the joint body, passes through the flexible tube, once the threaded part is tightened, the threaded part pushes the snapping part, and the snapping The member presses the metal pipe so that the front end thereof presses the contact surface in a sealed state, and is characterized in that, An internal thread portion is formed at one end portion of the inner peripheral surface of the through hole, and an external thread portion screwed with the internal thread portion is formed at the front end portion of the outer peripheral surface of the threaded member, and the length of the engaging member is set to The front end surface of the screw member abuts against the rear end surface of the engaging member shorter than the distance from the end surface of the joint main body opening at one end of the through hole to the contact surface. 2. The flexible pipe joint according to claim 1, wherein an annular seal member is provided on the contact surface, and the front end surface of the metal pipe presses the contact surface through the seal member. 3. The flexible pipe joint according to claim 1, wherein the part of the threaded member protruding outward from the through hole is made of a material that prevents liquid from permeating and allows gas permeation. The air-permeable member is provided with its inner and outer ends facing the inner and outer spaces of the threaded member. 4. The joint for a flexible pipe according to claim 1, wherein a portion of the inner peripheral surface of the through hole near the contact surface is formed so as to follow the opening from one end of the through hole. The engaging member moves toward the contact surface side, and uses the inclined surface to approach the outer periphery of the metal pipe. face-to-face movement. 5. The flexible pipe joint according to claim 1, wherein the flexible pipe further has a coating pipe provided on the outside of the metal pipe, and a waterproof pipe is provided on the inner peripheral surface of the threaded member. The waterproof member has a predetermined level of frictional resistance, is in contact with the outer peripheral surface of the covering tube, and prevents the intrusion of liquid from between the inner peripheral surface of the screw member and the outer peripheral surface of the covering tube. 6. The joint for flexible pipes according to claim 1, wherein the engaging member is rotatably mounted on the outer peripheral surface of the metal pipe, and the front end surface of the threaded member abutting with each other and At least one of the rear end faces of the engaging member is provided with a coating made of a material having a smaller friction coefficient than the material constituting the screw member and the material constituting the engaging member in order to reduce the frictional resistance therebetween. coating.

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