JP2018053959A - Pipe joint structure for flexible pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact pipe joint structure exhibiting high sealability against a flexible pipe.SOLUTION: A pipe joint structure for a flexible pipe has a ring seal unit body where a seal material S is assembled into a seal material holding ring 25 in a state of slightly enlarging a diameter. When a flexible pipe P is inserted and then a tip of the pipe P contacts with the seal material holding ring 25, the seal material S is released, goes beyond a first crest part 2F of the pipe P with its diameter enlarged in radial outward directions X, X, and falls in a first trough part 4F of the pipe P.SELECTED DRAWING: Figure 15

Description

  The present invention relates to a pipe joint structure for a flexible pipe (flexible pipe).

  Conventionally, a pipe joint structure as shown in FIG. 16 has been used. In particular, the one shown in FIG. 16 is used as a one-touch fitting for gas, and in the inner space of the joint body 40, a thermal expansion rubber 41 as a refractory part, a seal rubber 42 having a single cross-sectional shape, and imparting reduced diameter elastic force The spring-attached retaining ring 43 is sequentially arranged from the back to the front so that the outer surface of the flexible pipe P is in contact with or locked with the screw ring 44 from the outer side to the joint body 40. The pipe P is screwed to prevent the pipe P from being removed, and the pipe is sealed with the seal rubber 42 to prevent external leakage of gas.

The seal rubber 42 is only pressed in the axial direction only by the compression ratio of the insertion of the flexible pipe P. In particular, on the outer peripheral surface of the flexible pipe P, the top of the ridge 45 is scratched. In such a case, there is a risk of causing external leakage of gas (gas). (Note that the top of the ridge 45 of the flexible pipe P is easily damaged by collision with other objects.)
Therefore, a technique to improve the sealing performance by adding an O-ring and dropping the O-ring into the valley of the flexible pipe P can be considered. Conventionally, a pipe joint structure as shown in FIGS. 17 to 19 has been proposed. (See Patent Document 1).

  17 shows a pipe not inserted state, FIG. 18 shows a pipe insertion state, and FIG. 19 shows a pipe insertion completed state. Inside the joint body 40, an O-ring holding ring 48 elastically biased by a coil spring 47 is provided. The O-ring holding ring 48 includes a thin cylindrical portion 48A and an inner flange-shaped contact piece 48B extending radially inward from the inner peripheral surface of the cylindrical portion 48A. The contact piece 48B The function of receiving the elastic urging force of the coil spring 47 and the tip of the pipe P inserted as shown in FIGS. 17 to 18 abut against the elastic urging force of the coil spring 47. It also has a pipe contact function that moves to the left in the figure.

In the state where the pipe is not inserted in FIG. 17, the O-ring 49 as a seal material is elastically expanded and held in a cylindrical shape 48 </ b> A of the holding ring 48 in an externally fitted state.
In particular, the outer diameter D ₄₈ of the cylindrical portion 48A is much larger than the outer diameter D ₀ of the pipe P so that the inserted pipe P can be inserted into the cylindrical portion 48A. That is, the outer diameter D ₀ of the pipe P, a gap between the cylindrical portion 48A and the pipe P, the sum of the thickness of the cylindrical portion 48A, etc., a fairly large outer diameter D ₄₈ has the cylindrical portion 48A, therefore, As a pipe joint with no pipe inserted as shown in FIG. 17 (compared to the case where the O-ring 48 is not expanded and contracted in a free state) (Diaelastically deformed state).

  Thereafter, as shown in FIG. 18, when the pipe P is inserted, the tip end surface of the pipe P comes into contact with the inner flange-shaped contact piece 48B, and the O-ring holding ring 48 pushed in the left direction in the drawing. The O-ring 49 drops into the second pipe trough 50 from the tip by its own elastic contraction force.

  Next, as shown in FIG. 19 (from FIG. 18), the O-ring 49 was pressed against the tapered surface 51 of the hole of the joint body 40 and was pressed between the tapered surface 51 and the pipe trough 50. O-ring 49 provides a sealing function.

JP 7-174274 A

However, the pipe joint as shown in FIGS. 17 to 19 has the following problems.
That is, the assembled pipe joint may be stocked and stored in a distribution process or a work site for a long period of time without being used.

  As described above, the O-ring 49 made of elastomer (rubber) keeps the unused state (see Fig. 17) in the expanded elastic deformation state --- the state in which it is elastically extended to a considerably large diameter. As a result, the elasticity of the O-ring 49 is significantly reduced due to the so-called creep phenomenon, etc., and it is difficult to drop into the trough 50 of the flexible pipe P, or the sealing performance (due to insufficient elastic adhesion) There is a problem that decreases.

Further, there is a possibility that the edge of the holding ring 48 shown in FIGS. 17 to 19 may damage the O-ring 49, and the number of the coil spring 47 and other parts is large, resulting in a complicated structure.
Therefore, a sealing structure (mechanism) such as an O-ring holding ring 48, an O-ring 49, and a coil spring 47 shown in FIGS. 17 to 19 is added to a conventional pipe joint for a flexible pipe as shown in FIG.・ It can be said that there was a problem that it was difficult to apply.

  The pipe joint structure for a flexible pipe according to the present invention is provided with an annular recess into which a sealing material can be expanded and contracted in the radial direction in a joint body; and an inner side surface of the annular recess; A sealing material holding ring is provided at the corner with the final seal hole formed on the inner side of the joint body relative to the annular recess, and arranged in contact with the flexible pipe not inserted; A ring / seal unit body assembled to the seal material holding ring in a state where the flexible pipe is not inserted and the seal material is elastically minutely expanded in diameter is formed; holding the seal material of the ring / seal unit body When the ring comes into contact with the tip of the inserted flexible pipe, it is pushed into the final seal hole together with the flexible pipe, and the seal material of the ring / seal unit body is separated and released from the seal material holding ring. Separated; release The sealing material thus guided is guided by the slope surface of the first peak at the tip of the flexible pipe to be inserted, the inner side surface of the annular recess, and the outer side surface of the annular recess. It is configured to expand outwardly and exceed the top of the first peak; and further, the sealing material beyond the top reaches the first trough of the flexible pipe by its reduced diameter elastic force. In the connected state, the sealing material in the dropped state is configured to be pressed against the inner peripheral surface of the final seal hole and sealed.

  The sealing material holding ring includes an annular base and first and second projecting pieces alternately arranged in a radially outward direction from the annular base; and a joint In the longitudinal cross-sectional view including the shaft center, the first projecting piece and the second projecting piece have an inclination angle different from the joint shaft center in the state where the flexible pipe is not inserted in the state where the flexible pipe is not inserted. In the V-shaped storage space, which is formed by the first projecting piece having a large inclination angle and the second projecting piece having a small inclination angle, which gradually expands outward in the radial direction and outward of the joint body, The first projecting piece is locked to the corner when the flexible pipe is not inserted; the second projecting piece is elastic when the sealing material is not inserted. Diameter reduction prevention function to prevent diameter reduction deformation, and the slope surface of the first peak at the tip of the inserted flexible pipe abuts A pipe pushing force receiving function; when the second projecting piece comes into contact with the inclined surface at the tip of the flexible pipe and receives the pipe pushing force, it is locked to the corner portion. A seal member that is stored and held while the large inclination angle of the first projecting piece is decreased and the expansion angle of the V-shaped storage space is decreased is separated and released from the V-shaped storage space. It is.

  In addition, the joint main body has a guide insertion cylinder portion that is slidably inserted into the annular base portion of the seal material holding ring.

In addition, the diameter of a virtual contact circle that connects a plurality of points or minute line segments in which the tip of the second projecting piece of the seal material retaining ring contacts the slope surface of the first peak portion of the tip of the flexible pipe Is D _y , the outer diameter of the flexible pipe is D _0, and the valley diameter of the outer periphery of the flexible pipe is D _i , the dimension of the second projecting piece so that the following formula (1) is satisfied. The shape was set.
_{D i +0.20 · (D 0 -D} i) ≦ D y ≦ D i +0.75 · (D 0 -D i) ...... Equation (1)

  Further, the sealing material has an arcuate first convex portion on the inner peripheral side, an arc-shaped second convex portion on the outer peripheral side, and small arc-shaped ear portions protruding left and right. Furthermore, the axial dimension was set larger than the radial dimension in the cross section.

  In addition, when the sealing material is in the state of being dropped into the first trough and the pipe is connected, the inclined side surface portion of the first convex portion from the inner peripheral surface portion of the ear portion of the sealing material. The first convex portion is in a non-contact state in which a minute gap portion is formed between the first convex portion and the bottom of the first valley portion continuously in close contact with the flexible pipe.

Further, the inner diameter of the sealing material assembled in the sealing material holding ring in an elastically minute diameter expanded state when the flexible pipe is not inserted is D _10, and the valley bottom diameter of the outer peripheral surface of the flexible pipe is D _i. When the outer diameter of the flexible pipe is D ₀ , the following formula (2) is established.
D _{i +} 0.10 · (D ₀ −D _i ) ≦ D ₁₀ ≦ D _i + 0.70 · (D ₀ −D _i ) (2)

  According to the pipe joint structure for a flexible pipe according to the present invention, the sealing material is elastically maintained in a minute diameter expanded state during the unused period, and the elastic biasing force ( (Elasticity) is prevented from being reduced or lost, and stably exhibits excellent sealing performance. In addition, the overall size can be reduced, and the number of parts can be reduced. In addition, the seal material once expanded radially outward, subsequently reduced radially inward, and immediately after the first peak of the flexible pipe, it fell into the first valley, It can penetrate into the inner part of the final seal hole (together with the pipe tip) and smoothly and reliably connect the pipe. Furthermore, it is possible to lightly insert the flexible pipe.

FIG. 2 is a simplified cross-sectional view showing an embodiment of the present invention in a state where a pipe is not inserted. It is sectional drawing which shows the middle of a pipe being inserted. It is sectional drawing which is in the middle of the pipe insertion, and shows just before a sealing material crosses the top part of a 1st peak part. It is sectional drawing which shows the state which is in the middle of the pipe insertion, and the sealing material is passing over the top part of the 1st peak part. It is sectional drawing which is in the middle of the pipe insertion, and shows a state where it falls into the 1st trough part of a sealing material. It is sectional drawing which shows a connection completion state. It is sectional drawing which shows an example of a sealing material, Comprising: (A) is whole sectional drawing, (B) is an expanded transverse sectional view. It is principal part expansion explanatory drawing, (A) is a principal part expansion which shows the mutual shape and dimensional relationship of the trough part and peak part of a flexible pipe, the internal peripheral surface of the hole part for final seals, and a sealing material. It is explanatory drawing, (B) is a principal part expanded explanatory view which shows the state of elastic deformation of a sealing material in a connection completion state, and surface pressure distribution. It is a front view which shows an example of a sealing material holding ring. 9A is an end view of FIG. 9, and FIG. 9A is an AA end view of FIG. 9, and FIG. 9B is an BB end view of FIG. 9. It is a front view of a ring seal unit body. It is a rear view of a ring seal unit body. It is a front view of a pipe retaining member. It is a principal part expanded sectional view of the ring seal unit body which shows the state before an assembly | attachment in a coupling main body. It is a principal part expanded sectional view for demonstrating the dimensional relationship, the positional relationship, and an effect | action of a sealing material holding ring, a sealing material, a flexible pipe, and an annular recessed part. It is sectional drawing which shows a prior art example. It is a principal part sectional view of a pipe not inserted state showing another conventional example. It is principal part sectional drawing which shows the other prior art example in the middle of pipe insertion. It is a principal part enlarged view of a pipe connection completion state.

Hereinafter, the present invention will be described in detail based on the illustrated embodiment.
In one embodiment shown in FIGS. 1 to 15, P is a flexible pipe to be connected, which is also called a flexible pipe, a flexible pipe, etc., and independent annular ridges and valleys are alternately formed. It comprises a thin metal tube 5 and a plastic coating layer 6 as a coating.
In the present invention, the peaks and valleys of the metal pipe 5 are referred to as peaks 2 and valleys 4 of the flexible pipe P. The reason for this is that the pipe joint structure according to the present invention is connected to the pipe joint 1 with the six ridges (or seven ridges) of the metal pipe 5 exposed from the tip of the pipe, as is apparent from FIGS. This is because the peaks 2 and valleys 4 of the exposed metal pipe 5 are important components.

Reference numeral 3 denotes a joint body, and in the illustrated example, a socket type is shown. However, this may be an elbow type or a cheese type, and a cap nut 7 is screwed not only to one end of the joint body 3 but also to a plurality of ends. It is also preferred that
The joint body 3 has a passage hole 8 extending along the axis L ₃ , and a tapered male screw portion 9, a work tool gripping hexagon portion 11, and a male screw portion 12 on the outer peripheral surface. Are arranged sequentially in the axial direction, and the female screw portion 13 of the cap nut 7 is screwed to the male screw portion 12. Further, the cap nut 7 has a relatively long dimension in the axial direction and has a sealing groove 14 in the vicinity of the opening end, and a T-shaped seal 15 is fitted into the groove 14. As shown in the figure, the pipe P is sealed in close contact with the outer peripheral surface of the coating layer 6 under the connection completion state.
In addition, between the stepped surface 16 inside the cap nut 7 and the end surface of the male threaded portion 12 of the joint body 3, a pipe extraction prevention tool that prevents the pipe P from being pulled out when the pipe is completely inserted. 17 (see FIG. 13) is provided in a pinched form.

The hole 8 of the joint body 3 includes a first hole 8A having a large diameter, a second hole 8B having a slightly smaller diameter, and a third hole having a smaller diameter from the opening end face side to which the cap nut 7 is screwed. A hole 8C and a small-diameter fourth hole 8D are sequentially disposed, and the first, second, and third stepped surfaces 18A, 18A, 8A, 8B, 8C, and 8D are formed at the boundaries between the holes 8A, 8B, 8C, and 8D. 18B and 18C are provided. Also, a thin cylindrical (described later) insertion tube portion 20 is provided continuously from the inner peripheral end of the third stepped surface 18C. The inner cylindrical portion 20 is provided concentrically with the third hole portion 8C, and the third hole portion 8C, the outer peripheral surface of the inner cylindrical portion 20 and the third stepped surface 18C (the cap nut 7 An open cylindrical space 21 is formed on the outer side of the axial. In addition, the inner peripheral surface of the insertion tube portion 20 and the fourth hole portion 8D are continuously formed to have substantially the same diameter, and directly constitute a flow path in contact with the fluid.
Then, a thermal expansion rubber 41 and a seal rubber 42 similar to those in FIG. 16 showing the conventional example are fitted into the large-diameter first hole 8A on the opening end side.

S is a sealing material made of an elastic material such as rubber. This sealing material S is shown by arrows X _{1 to} X ₆ in the enlarged view of FIG. 15 as shown in FIGS. As described above, an annular recess 30 is provided inside the joint body 3 that can be intruded while expanding and contracting in the radial direction R. Specifically, the annular recess 30 is formed in an opening in the radial inward direction by the second stepped surface 18B, the second hole 8B, and the inner end surface 41A of the thermal expansion rubber 41.

Reference numeral 25 denotes a sealing material retaining ring, which is formed of a pressed metal plate having a thickness of about 0.15 to 3 mm, as illustrated in FIGS. 9 and 10, and is illustrated in FIGS. 11, 12, 14, and 1. As shown, the sealing material S is assembled in an elastically small diameter expanded state before assembly (incorporation) to the joint body 3 and in a state where the pipe is not inserted (as well as in the joint body 3). The ring / seal unit body U is formed. Further, the sealing material holding ring 25 includes a first base piece 31 and a second base piece 26 which are alternately arranged as an annular base portion 26 extending along a plane orthogonal to the axial center and projecting radially outward from the annular base portion 26. And a projecting piece 32.
In addition, in the longitudinal sectional view including the joint axis L ₃ , the first projecting piece 31 and the second projecting piece 32 have inclination angles θ ₁ and θ ₂ that are different from each other with respect to the joint axis L ₃ . When the pipe is not inserted (see FIGS. 1 and 14), the joint body is inclined to the outer side of the joint body—the first hole 8A side.

A sealing material S is formed in the V-shaped storage space 33 that gradually expands outward in the radial direction and outward of the joint body by the first protruding piece 31 having the large inclination angle θ ₁ and the second protruding piece 32 having the small inclination angle θ ₂ . Is stored and held (see FIGS. 1, 11, 12, and 14).
As shown in FIG. 14, the opening angle β ₀ of the V-shaped storage space 33 is θ ₁ −θ ₂ .

  Further, in the state where the pipe is not inserted as shown in FIG. 1, the inner side surface 34 of the annular recess 30 is formed on the inner side of the second stepped surface 18B and the annular recess 30. Further, a sealing material holding ring 25 is disposed in contact with a corner 36 of the final sealing hole 35 --- the third hole 8C--when the pipe is not inserted.

  Specifically, wait for the first projecting piece 31 of the retaining ring 25 to come into contact with the corner portion 36 between the second stepped surface 18B and the third hole 8C and to insert the pipe P. Yes. The corner portion 36 is preferably chamfered. Further, the final sealing hole portion 35 corresponds to the third hole portion 8C, and the sealing material S is pressed tightly in the final connection completed state as shown in FIG. This is the inner surface to be performed.

Further, the holding ring 25 and the sealing material S of the ring / seal unit body U will be described. As shown in FIGS. 1 and 14, the first projecting piece 31 is in the state in which the corner portion 36 is not inserted in the pipe. In contrast, the positioning function of locking is exhibited. The second projecting piece 32 comes into contact with the diameter reducing function for preventing the sealing material S from undergoing elastic diameter reduction, and the slope surface 22 of the first peak portion 2F at the tip of the flexible pipe P to be inserted. Thus, it can be said that a pipe pushing force receiving function for receiving the pipe pushing force F _P (see FIG. 15) from the inclined surface 22 is provided.

As shown in FIGS. 1 and 2, the second projecting piece 32 of the retaining ring 25 abuts on the slope surface 22 of the first peak 2F at the tip of the pipe P to be inserted, and the pipe as shown in FIG. Upon receiving the pushing force F _P, the first protrusion 31 which has been engaged with the corner portion 36, the large inclination angle theta ₁ is decreased, the expansion angle beta ₀ V-shaped receiving space 33, FIG. As shown in FIG. 14 (FIG. 1) to FIG. 15 (FIGS. 2 and 3), the sealing material S stored and held is released from the V-shaped storage space 33 while decreasing.
The holding ring 25 is pushed into the inner part of the cylindrical space 21 sequentially from FIG. 3 to FIG. 4 to FIG. 5 to FIG. 6 while separating and releasing the sealing material S.

By the way, since the annular base portion 26 of the retaining ring 25 is slidably fitted to the guide insertion tube portion 20 of the joint body 3, the retaining ring 25 may fall (tilt) smoothly. The occurrence of the problem that it is difficult to move the joint body 3 to the back is solved. In other words, an annular base portion 26 inserted through the guide in挿筒section 20 as slidable in the retaining ring 25 that is joint body 3 has, a pipe P smoothly with a small pipe pushing force F _P press Can be included.

The inner diameter of the sealing material S assembled in the holding ring 25 in an elastically small diameter expanded state when the flexible pipe is not inserted (see FIGS. 1, 14, 11, and 12) is D ₁₀ . the root diameter and D _i of the outer peripheral surface of the flexible pipe P, and the outer diameter of the flexible pipe P When D _0, is set as following equation (2) is satisfied.
D _{i +} 0.10 · (D ₀ −D _i ) ≦ D ₁₀ ≦ D _i + 0.70 · (D ₀ −D _i ) (2)
More preferably, the following equation (3) is set.
D _i + 0.20 · (D ₀ −D _i ) ≦ D ₁₀ ≦ D _i + 0.60 · (D ₀ −D _i ) (3)

  In the above formula, if it is less than the lower limit value, the pipe P is inserted from the state shown in FIG. 1 (FIG. 14), and the tip is inclined more than the apex of the first peak 2F as shown in FIG. 2 (FIG. 15). It becomes difficult for the sealing material S to smoothly transfer (separate from the holding ring 25) to the surface (gradient surface 22). On the other hand, if the upper limit is exceeded, the elasticity (elastic urging in the reduced diameter direction) may be reduced or lost due to the creep phenomenon when the sealing material S is unused (inventory) for a long period of time.

Now, the cross-sectional shape of the sealing material S will be described. As shown in FIG. 7, the arc-shaped first convex portion 61 having the radius R ₁ on the inner peripheral side and the arc-shaped second convex portion having the radius R ₂ on the outer peripheral side, as shown in FIG. and 62, and a small circular arc-shaped ears 63 and 63 of the protruded a radius R ₃ to the right and left, and, (shown in phantom) corners 64 of the first protrusion 61 and the ears 63, the radius R _The corners 66 (shown by dotted lines) of the second convex portion 62 and the ear portion 63 are bulged with a concave arc 67 having a radius R ₅ .

Then, the axial dimension (width dimension) W is set larger than the radial dimension (height dimension) H in the cross section. Specifically, 1.20 · H ≦ W ≦ 1.40 · H. Also, the center point P ₆₃ of the ear portion 63, the radial dimension (height) H ₆₃ from the vertex P ₆₁ of the first convex portion 61 is set larger than half of the height H. That is, the ears 63 and 63 are arranged so that 0.60 · H ≦ H ₆₃ ≦ 0.80 · H, and radially outward from the center of gravity of the cross section, and as shown in FIG. When it fits in the valley part, the parts indicated by points 68 and 68 are elastically compressed and deformed. Further, in the connection completion state shown in FIG. 6, the points 69 shown in FIG. 8A are elastically compressed against the inner peripheral surface of the third hole 8C (hole 35). Deform.

FIG. 8B shows the cross-sectional shape of the elastic deformation of the sealing material S and the distribution of the pressure contact surface pressure P ₁ under this connection completion state.
As can be seen from FIGS. 8A and 8B, the sealing material S maintains a stable posture with respect to the slopes of the valleys 4 and the peaks 2 of the pipe P in accordance with the unique cross-sectional shape described above. The elastic compression part (pressure contact part) indicated by points 68 (not generating twist) is continuous over the slope surface of the valley portion 4 and the slope surface of the peak portion 2.
In other words, 68A is a sandwich seal region by the right and left slope surface of the valley portion 4, and 68B is a press seal region by a pressing force in the radial inward direction from the final seal hole 35.

Furthermore, as shown in FIGS. 4 to 5, when the sealing material S falls into the valley portion 4 due to its reduced diameter elastic force, it is prevented from being twisted due to the presence of both ear portions 63, 63, and Since the width dimension (2 × R ₁ ) of the first protrusion 61 is smaller than the overall width dimension W (as shown in FIG. 7), the first protrusion 61 can smoothly slide (drop) toward the valley 4. In addition, when entering the final sealing hole 35 as shown in FIGS. 5 to 6, it is easy to sink toward the valley portion 4 while being elastically deformed, and the sandwiching seal area 68A and the pressing seal area (described above) 68B is continuously formed and exhibits excellent sealing properties (sealing performance). Further, when crossing the first peak portion 2F as shown in FIGS. 3 to 4, the apex vicinity region 70 of the first convex portion 61 of the sealing material S is easily damaged, but such an easily damaged apex. Since the neighboring region 70 is not in contact with the valley portion 4 of the pipe P (there is a gap portion 19), the sealing performance (sealing performance) can be further improved.

Next, referring back to FIGS. When the flexible pipe is not inserted, the sealing material S as the ring / seal unit body U is elastically minutely expanded, and the pipe P is inserted at the opening end position of the cylindrical space 21 as shown in FIG. Waiting (waiting).
When the seal material retaining ring 25 of the ring / seal unit body U abuts the tip of the inserted pipe P as shown in FIGS. 2 and 15, it is pushed together with the pipe P into the final seal hole 35. In rare cases (see FIGS. 3 and 4), the seal material S of the ring and seal unit body U is released from the seal holding ring 25 (see FIGS. 3, 4 and 15).

As shown in FIG. 15, the separated and released sealing material S has a gradient surface 22 on the distal direction side of the first peak portion 2F at the distal end of the flexible pipe P to be inserted, and an inner side of the annular recess 30. It is guided by one side 34 and the other side 41A on the outer side, and elastically expands in the radial outward direction X ₁ , X ₂ , beyond the top 23 (see FIG. 15) of the first peak 2F. (Indicated by the arrow X _{3 in} FIG. 15).
Furthermore, the sealing material S beyond the top 23 of the first peak portion 2F is subjected to its reduced diameter elastic force as shown by arrows X ₄ , X ₅ , X ₆ in FIG. 15 and FIGS. 4 to 5. Then, it slides into the first trough portion 4F of the pipe P, and the sealing material S falls.

As shown in FIG. 6, when the connection is completed, the seal material S in the lowered state is pressed against the inner peripheral surface of the final seal hole 35 (the surface pressure P shown in FIG. 8B). ₁ ) and seal.
8 and 6, the sealing material S is sandwiched between the pressing seal region 68B described above when the sealing material S is dropped into the first valley portion 4F and the pipe connection is completed. Over the seal region 68A, the first trough portion 4F of the flexible pipe P and the subsequent inclined surfaces (gradient surfaces) of the peaks 2 and 2 are sealed in a continuous manner. In other words, the seal material S is changed from the inner peripheral surface portion (corresponding to reference numeral 68B) of the left and right ears 63, 63 to the inclined side surface portion (corresponding to reference numeral 68A) of the first convex portion 61 in the pipe connection completed state. In a continuous manner, the first valley 4F of the pipe P and the inclined surfaces of the peaks 2 and 2 are pressed into a sealed state. The surface pressure distribution in the sealed state is indicated by the pressure contact surface pressure P ₁ in FIG. In this state, the first convex portion 61 is in a non-contact state in which the minute gap portion 19 is formed between the first convex portion 61 and the bottom of the first valley portion 4F.

  In this way, as the sealing material S, the vicinity of the top portion of the first convex portion 61 that is likely to be damaged when slipping into the first valley portion 4F beyond the first peak portion 2F is not involved in sealing. On the contrary, the sealing is securely performed in the sealing area indicated by reference numerals 68A and 68B which is not damaged. Moreover, as shown in FIG. 8 (B), the sealing material S has a right cross section having left and right ear portions 63 and 63 and a first convex portion 61 in order to maintain a correct posture without twisting. It is secured by its shape and exhibits high sealing performance while maintaining a stable posture.

Next, in FIG. 9 to FIG. 12, the sealing material holding ring 25 will be further described. The first projecting pieces 31 and the second projecting pieces 32 are alternately projected from the annular base portion 26. Each of the six pieces is provided with a central angle of °, and when viewed from the direction along the axis L ₃ , the width dimension of the second protrusion 32 is larger than the width dimension of the first protrusion 31, and The one projecting piece 31 is larger than the second projecting piece 32 in a radially outward direction. The reason why the width dimension (in the circumferential direction) of the second projecting piece 32 is set large is that, as shown in FIGS. 1 to 6, 14, and 15, the second projecting piece 32 is located with respect to the axis L ₃ . As shown in FIGS. 1 to 2 and 15, the inclination angle θ ₂ receives the pushing force from the pipe P by abutting against the inclined surface 22 of the pipe P that is reliably inserted with almost no change. This is because it is necessary to have a function of smoothly transferring (transferring) the sealing material S to the sloped surface 22.

On the other hand, the reason why the width dimension (in the circumferential direction) of the first protrusion 31 is set to be small is that FIG. 1 → FIG. 2 → FIG. 3 → FIG. However, this is because the inclination angle θ ₁ with respect to the axis L ₃ needs to change, and due to the (decrease) change in the inclination angle θ ₁ , the pipe P is abutted against the corner portion 36 and is waiting to be inserted. This is because the holding ring 25 can smoothly enter the hole 35 and the sealing material S stored and held in the V-shaped storage space 33 is smoothly separated and released.
The second protrusion 32 has its distal end 32A is but abuts against the inclined surface 22 of the first crest portion 2F of the distal end of the flexible pipe P, when viewed from the axis L ₃ directions, contact sites, a plurality of points To minute line segments (small arc-shaped line segments).

9, 11, and 15, a virtual contact circle Y that connects all of the plurality of points or minute line segments is assumed, and the diameter of the virtual contact circle Y is expressed as D _y . To do. When the outer diameter of the flexible pipe P is D ₀ and the valley bottom diameter of the outer periphery of the flexible pipe P is D _i , the size and shape of the second projecting piece 32 are set so that the following formula (1) is established. Set.
_{D i +0.20 · (D 0 -D} i) ≦ D y ≦ D i +0.75 · (D 0 -D i) ...... Equation (1)
In other words, in FIG. 15, the position where the tip 32A of the second projecting piece 32 abuts on the sloped surface 22 of the pipe P exists on the middle of the mountain of 20% to 75% from the valley bottom of the outer peripheral surface of the pipe. .

More preferably, the following equation (4) is established.
D _i + 0.25 · (D ₀ −D _i ) ≦ D _y ≦ D _i + 0.65 · (D ₀ −D _i ) (4)
In the above formula, if the tip of the pipe P is eccentrically inserted if it is less than the lower limit value, the second projecting piece 32 does not contact the tip of the pipe P over 360 °, and the holding ring 25 When the posture is abnormally inclined, it becomes difficult to smoothly remove the sealing material S, and it is also difficult to transfer to the inclined surface 22. On the other hand, if the upper limit is exceeded, there is a risk that the elasticity may be reduced or lost due to the creep phenomenon when the sealing material S is unused (in stock) for a long period of time.

  Next, the pipe removal preventing tool 17 will be described. In FIG. 13 and FIG. 1 to FIG. 6, a plurality of slits 27 are formed in the radial direction from the inner periphery of the thin metal plate. A small circular hole 28 is continuously provided at the outer end portion in the direction, and is folded into a “<” shape as shown in FIGS. 1 to 6 by press working along a circle 29 connecting all the small circular holes 28. Bend. A large number of locking claw pieces 37 are formed along the inner peripheral edge by the slit 27, and the outer end surface of the joint body 3 and the cap nut 7 are arranged so that the claw pieces 37 face the inside of the joint body 3. The stepped surface 7A is held in a sandwiched manner. With such a simple petal shape and holding structure, it is possible to achieve a compact design in which the axial dimension of the joint hardly increases, and the claw pieces 37 are elastic to the peak portion 2 of the flexible pipe P easily and reliably. Can be locked while deforming.

In the state of FIG. 3 from 2, for some reason the pipe P coming inserted in the arrow F _p direction, when such pullout in the direction opposite to the arrow F _p, At a 2 (3), the retaining ring A “gap” is generated between the 25 second projecting pieces 32 and the thermal expansion rubber 41, and the sealing material S is deformed radially inwardly from the “gap” due to its reduced diameter elasticity. There is a risk of leaving.
However, in the state of FIG. 2, the locking claw piece 37 of the pipe removal prevention tool 17 is restored by its own elasticity in the direction of the arrow M, and immediately after the pipe P is inserted a little, As shown in FIG. 3, the claw piece 37 swings and engages with the fifth peak portion 2K from the first peak portion 2F, so that the seal material S can be prevented from being released radially inward.
In addition, it is not necessarily limited to the 5th peak part 2K, but it is also free to arrange the pipe extraction preventing tool 17 at a position where the claw piece 37 is locked to another peak part 2 (not shown). 3, the claw piece 37 may be engaged with the peak portion 2 of the flexible pipe P in the insertion state where the “gap” is the largest and shown in FIG.
The inner peripheral surface of the cap nut 7 has a size close to the coating layer 6 of the pipe P, but has an inner diameter sufficiently larger than the outer diameter size (pipe outer diameter D ₀ ) of the metal tube 5.

In the present invention, the conventional coil spring 47 shown in FIGS. 17 to 19 is omitted, and the first projecting piece 31 of the holding ring 25 itself (plate spring-like) made of a thin metal plate is elastically attached. With a configuration in which a force can be applied to the inner peripheral surface of the hole 35 in a contact state and an appropriate pushing force can be applied to the pipe P being inserted, the parts are simplified and the internal structure is made compact. Yes.
In addition, in the state shown in FIGS. 2 to 3, the sealing material S is prevented from falling off in the radial inward direction from the “gap” by locking the pipe peak 2K with the claw piece 37 of the pipe pull-out prevention tool 17. As described above, as described above, the present invention further prevents the sealing material S from further falling off in the radial inward direction from the “gap” by the following configuration.
(I) As shown in FIG. 7, the width dimension W of the sealing material S is larger than the height dimension H (assuming that H> W). (ii) The retaining ring 25 has a second protrusion 32 extending long enough to protrude. (iii) Since the insertion tube portion 20 is provided so that the posture of the holding ring 25 can be always kept in a correct posture so as not to tilt, the “gap” can be formed evenly over 360 °.

As described in detail above, the present invention provides the joint body 3 with the annular recess 30 into which the sealing material S can be expanded and contracted in the radial direction R; A sealing material holder disposed in contact with the side face 34 and the corner 36 of the final sealing hole 35 formed on the inner side of the joint body with respect to the annular recess 30 when the flexible pipe is not inserted. A ring / seal unit body U assembled to the seal material holding ring 25 in a state where the flexible seal pipe is not inserted and the seal material S is elastically minutely expanded in diameter. The sealing material holding ring 25 of the ring / seal unit body U is pushed together with the flexible pipe P into the final sealing hole 35 when it comes into contact with the tip of the inserted flexible pipe P, and The seal material S of the ring / seal unit body U is a seal material retaining ring 25. The sealing material S separated and released from the inclined surface 22 of the first peak portion 2F at the tip of the flexible pipe P to be inserted and the one side surface 34 on the inner side of the annular recess 30 It is configured to be guided by the other side surface 41A on the outer side and expand in the radial outward direction X ₁ , X ₂ to exceed the top portion 23 of the first peak portion 2F; The sealing material S falls into the first trough portion 4F of the flexible pipe P by its reduced diameter elastic force; the sealing material S in the lowered state is used for the final seal under the connected state. Since the inner surface of the hole 35 is pressed against and sealed to the inner peripheral surface, the first trough 4F is formed by the sealing material S that does not lose its elastic force as compared with the conventional FIG. Ensuring sufficient sealing performance, and with the annular recess 30, the sealing material S is clever and smooth only in the radial direction. Nde 落込 to ensure first valley 4F while moving, can exhibit a stable more reliable sealing performance. In addition, the sealing material S pre-assembled as the ring / seal unit body U maintains a small diameter expanded state from the diameter of the free state, and even if it is not used for a long period of time, it loses elasticity (due to creep phenomenon). Can be prevented. Further, the holding ring 25 smoothly enters from the corner portion 36 into the hole portion 35 together with the pipe P and escapes, and the resistance is small.
Moreover, since the seal material S is assembled in advance as the ring / seal unit body U, handling is easy, assembly as a joint is simplified, and damage to the seal material S can be prevented.

The sealing material holding ring 25 includes an annular base portion 26 and first and second protruding pieces 31 and 32 that are alternately arranged in a radially outward direction from the annular base portion 26. In addition, in the longitudinal sectional view including the joint axis L ₃ , the first projecting piece 31 and the second projecting piece 32 are inclined at different angles θ ₁ and θ with respect to the joint axis L ₃ . _{2 with a} flexible pipe not inserted, and is formed of a first protrusion 31 having a large inclination angle θ ₁ and a second protrusion 32 having a small inclination angle θ ₂ , which is inclined outwardly from the joint body. The sealing material S is stored and held in a V-shaped storage space 33 that gradually expands outward and outward from the joint body; the first projecting piece 31 is formed in the corner portion 36 in a state where a flexible pipe is not inserted. The second projecting piece 32 is inserted into the sealing member S to prevent the sealing material S from undergoing elastic contraction deformation when the flexible pipe is not inserted, and is inserted. A pipe pushing force receiving function in which the slope surface 22 of the first peak portion 2F at the tip of the flexible pipe P abuts; the slope surface at the tip of the flexible pipe P into which the second projecting piece 32 is inserted. When the pipe 22 is in contact with the pipe and receives a pushing force, the large inclination angle θ _{1 of} the first projecting piece 31 locked to the corner portion 36 is reduced, and the V-shaped storage space 33 is expanded at an opening angle B. _Since the sealing material S stored and held while ₀ is reduced is separated and released from the V-shaped storage space 33, the sealing material S can be formed into an extremely small and simple holding ring 25 and assembled. Can be skillfully separated and released. In this way, the entire joint structure is also compact.

  In addition, since the joint body 3 has a guide insertion cylindrical portion 20 that is slidably inserted into the annular base portion 26 of the seal material holding ring 25, The seal material retaining ring 25 always maintains a normal posture (not an abnormal posture inclined from the plane orthogonal to the axis), and the seal material S is simultaneously discharged over 360 °, and the slope surface of the pipe P inserted. It is possible to transfer to 22. Further, the “gap” generated when the inserted pipe P is slightly pulled out can prevent the seal material S from falling off from a part in the circumferential direction in the radial inward direction.

Further, the sealing material S has a cross-sectional shape in which an arc-shaped first convex portion 61 on the inner peripheral side, an arc-shaped second convex portion 62 on the outer peripheral side, and a small arc-shaped ear portion 63 projecting left and right. 63, and the axial dimension W is set to be larger than the radial dimension H in the cross section. Therefore, when moving sequentially to FIGS. Then, as shown in FIG. 15, when moving in the direction of arrow X ₁ → X ₂ → X ₃ → X ₄ → X ₅ → X ₆ , Get over and drop smoothly to the first valley 4F.

In addition, when the sealing material S is in the state of dropping into the first valley 4F and the pipe connection is completed, the first convex portion is formed from the inner peripheral surface portion of the ear portion 63 of the sealing material S. In close contact with the flexible pipe P over the inclined side surface portion of 61, the first convex portion 61 is formed with a minute gap portion 19 between the bottom of the first valley portion 4F. Since it is configured to be in a non-contact state, as shown in FIG. 8, it is possible to perform stable and reliable sealing at the first valley portion 4F. Moreover, due to the unique cross-sectional shape of the sealing material S, the sandwiching seal region 68A and the pressing seal region 68B are formed in a state where the sealing material S is dropped and compressed into the first valley portion 4F of the flexible pipe P ( (See FIG. 8 (A)) The pressure contact surface pressure P ₁ is also generated as shown in FIG. 8 (B), and it is the most stable and cleverly intimate contact with the flexible pipe P, and exhibits excellent sealing performance (sealability). it can.
In addition, by forming the minute gap portion 19, a region 70 near the apex of the first convex portion 61 of the sealing material S that may be damaged or damaged when the first peak portion 2F is exceeded is temporarily provided. The danger associated with the seal area is avoided.
Further, by forming the minute gap portion 19, the sandwiching seal region 68A and the pressing seal that are in close contact with each other from the inner peripheral surface portion of the ear portion 63 to the inclined side surface portion of the first convex portion 61 of the sealing material S are formed. The surface pressure P ₁ (see FIG. 8B) in the region 68B (see FIG. 8A) increases, and the sealing performance is further improved.

2 Mountain part 2F First mountain part 3 Joint body 4 Valley part 4F First valley part
19 Gap
20 Insertion tube
22 Inclined surface
23 Top
25 Retaining ring
26 Torus base
30 Annular recess
31 First protrusion
32 Second protrusion
32A tip
33 V-shaped storage space
34 One side
35 Hole for final seal
36 corners
41A Other side (inner end face)
61 1st convex part
62 2nd convex part
63 Ear D ₀ Pipe outer diameter D ₁₀ Inner diameter D _i Valley bottom diameter D _y Diameter of virtual contact circle H Radial dimension (height dimension)
L ₃ axis P flexible pipe R Radial direction S sealant U-ring seal unit body W axial dimension (width)
X ₁ , X ₂ radial outward direction Y virtual contact circle θ ₁ , θ ₂ inclination angle β ₀ opening angle (expansion angle)

Claims (7)

In the joint body (3), an annular recess (30) is provided in which the sealing material (S) can be expanded and contracted in the radial direction (R),
A corner (36) between one side surface (34) on the inner side of the annular recess (30) and a final seal hole (35) formed on the inner side of the joint body from the annular recess (30) And a sealing material retaining ring (25) disposed in contact with the flexible pipe not inserted,
In addition, the ring / seal unit body (U) assembled to the seal material retaining ring (25) is configured with the seal material (S) elastically having a minute diameter expansion state with the flexible pipe not inserted. And
When the seal material retaining ring (25) of the ring / seal unit body (U) comes into contact with the tip of the inserted flexible pipe (P), the flexible pipe ( P) and the seal material (S) of the ring / seal unit body (U) is separated and released from the seal material holding ring (25),
The separated and released sealing material (S) includes the slope surface (22) of the first peak (2F) at the tip of the flexible pipe (P) to be inserted, and the inner side of the annular recess (30). Are guided by one side surface (34) and the other side surface (41A) on the outer side to expand in the radial outward direction (X ₁ ) (X ₂ ), and the top portion (23F) of the first peak portion (2F) ) And configured to exceed
Furthermore, the sealing material (S) beyond the top (23) falls into the first trough (4F) of the flexible pipe (P) by its reduced diameter elastic force,
The sealing material (S) in the depressed state is configured to be pressed and sealed against the inner peripheral surface of the final sealing hole (35) under the connection completion state. A pipe joint structure for a flexible pipe. The sealing material holding ring (25) includes an annular base (26) and first protrusions (31) and second protrusions alternately arranged in a radially outward direction from the annular base (26). A piece (32),
In addition, in the longitudinal sectional view including the joint axis (L ₃ ), the first projecting piece (31) and the second projecting piece (32) are different in size from the joint axis (L ₃ ). With the inclination angle (θ ₁ ) (θ ₂ ), the flexible pipe is not inserted, and the joint body is inclined to the outside of the joint body. The first protrusion (31) having the large inclination angle (θ ₁ ) and the small inclination angle ( The sealing material (S) is stored and held in a V-shaped storage space (33) formed by the second projecting piece (32) of θ ₂ ) that gradually expands outward in the radial direction and outward in the joint body.
The first protrusion (31) is locked to the corner (36) in a state where the flexible pipe is not inserted,
The second projecting piece (32) includes a diameter reduction preventing function for preventing the sealing material (S) from undergoing elastic diameter reduction deformation when the flexible pipe is not inserted, and a flexible pipe (P A pipe pushing force receiving function with which the inclined surface (22) of the first peak (2F) at the tip of
When a pipe pushing force is received by contacting the inclined surface (22) at the tip of the flexible pipe (P) into which the second projecting piece (32) is inserted, the second projecting piece (32) is locked to the corner (36). The large slant angle (θ ₁ ) of the first projecting piece (31) is reduced and the expansion angle (B ₀ ) of the V-shaped storage space (33) is reduced, and the sealing material (stored and held) The pipe joint structure for a flexible pipe according to claim 1, wherein S) is separated and released from the V-shaped storage space (33).   The joint body (3) has a guide insertion tube portion (20) inserted therein so as to be freely slidable through the annular base portion (26) of the seal material retaining ring (25). 2. A pipe joint structure for a flexible pipe according to 2. The tip (32A) of the second projecting piece (32) of the seal material retaining ring (25) abuts on the inclined surface (22) of the first peak (2F) at the tip of the flexible pipe (P). The diameter of a virtual contact circle (Y) connecting a plurality of points or minute line segments is (D _y ), the outer diameter of the flexible pipe (P) is (D ₀ ), and the flexible pipe (P) 3. The pipe joint structure for a flexible pipe according to claim 2, wherein the dimension and shape of the second projecting piece (32) are set so that the following mathematical formula (1) is satisfied, where the valley diameter of the outer periphery of the pipe is (D _i ). .
_{D i +0.20 · (D 0 -D} i) ≦ D y ≦ D i +0.75 · (D 0 -D i) ...... Equation (1)   The sealing material (S) has a transverse cross-sectional shape of an arcuate first convex part (61) on the inner peripheral side, an arcuate second convex part (62) on the outer peripheral side, and a small circle protruding left and right. 5. An arc-shaped ear (63) (63) is provided, and the axial dimension (W) is set larger than the radial dimension (H) in the cross section. Pipe joint structure for flexible pipes. In the state where the sealing material (S) is dropped into the first valley (4F) and the pipe connection is completed,
The sealing material (S) is in close contact with the flexible pipe (P) continuously from the inner peripheral surface portion of the ear portion (63) to the inclined side surface portion of the first convex portion (61). 6. The pipe joint for flexible pipes according to claim 5, wherein the first convex part (61) is in a non-contact state in which a minute gap part (19) is formed between the first convex part (61) and the bottom part of the first valley part (4F). Construction. The inner diameter of the sealing material (S) assembled to the sealing material holding ring (25) in an elastically small diameter expanded state when the flexible pipe is not inserted is (D ₁₀ ), and the flexible pipe (P) 2. The pipe joint for flexible pipes according to claim 1, wherein the following equation (2) is established, where (D _i ) is a valley bottom diameter of the outer peripheral surface and (D ₀ ) is an outer diameter of the flexible pipe (P): Construction.
D _{i +} 0.10 · (D ₀ −D _i ) ≦ D ₁₀ ≦ D _i + 0.70 · (D ₀ −D _i ) (2)

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