Pipe joint and its installation method

Abstract

To provide a pipe joint of high durability capable of preventing slipping-off of a male member from a female member even when relative rotation is repeated between the female member and the male member due to vibration and the like in a state that a fluid pressure is acted, and a mounting method of the same.SOLUTION: A pipe joint includes a cylindrical adapter 2 retaining a diameter expandable and contractible C-ring 7 in a first locking groove 5 formed on an inner peripheral surface, and a body 3 having a cylindrical shape provided with a second locking groove 15 on an outer peripheral surface and connected to the adapter 2 via the C-ring 7 by being inserted while pressing and expanding the C-ring 7. The C-ring 7 is composed of a partially cut-off circular ring having a rectangular longitudinal cross-section, and a first taper face 5a reduced in diameter toward an opening direction of the adapter 2 is disposed on an opening-side part of the adapter 2 of the first locking groove 5. After mounting the adapter 2 on an apparatus, the body 3 is connected to the adapter 2.SELECTED DRAWING: Figure 6C

Description

Technical Field

[0001] The present invention relates to a pipe joint and a method for installing the same.

Background Art

[0002] A pipe joint includes a female member (adapter) and a male member (body) that are connected to each other via an elastic ring member that can expand and contract in diameter. This type of pipe joint is used to easily connect one pipe and another pipe in one touch in automobiles including commercial vehicles (such as trucks and buses), construction machinery, machine tools, etc. Various proposals have been made regarding such pipe joints (see, for example, Patent Documents 1 and 2).

[0003] Patent Document 1 discloses a pipe joint in which a female member and a male member of the pipe joint are connected via an elastic ring member, and the connection between the female member and the male member is not easily released inadvertently even when a high-pressure fluid acts.

[0004] Also, Patent Document 2 discloses a pipe joint in which once the female member and the male member are connected, they cannot be separated from each other. Specifically, when fluid pressure acts, a force in the direction opposite to the insertion direction (the direction in which the male member comes off) is applied to the male member due to the increase in pressure. This pipe joint is configured such that the elastic ring member enters the groove of the female member so that the female member and the male member cannot be separated.

[0005] Here, an example of a conventional pipe joint is shown in FIGS. 16 and 17A to 17C. FIG. 16 is a half-cut longitudinal sectional view of the conventional pipe joint, and FIGS. 17A to 17C are enlarged detailed views of part D of FIG. 16 showing changes in the behavior of the elastic ring member when fluid pressure acts on the conventional pipe joint shown in FIG. 16.

[0006] The illustrated pipe joint 101 includes a female member 102 and a male member 103 that are connected to each other. On the inner peripheral surface of the female member 102, a first locking groove 105 having a rectangular longitudinal section is formed over the entire circumference, and an elastic ring member 107 that can be expanded and contracted with a part cut out is held in the first locking groove 105. On the other hand, a second locking groove 115 is formed on the outer peripheral surface of the male member 103. If the male member 103 is inserted into the female member 102 from above, for example, the elastic ring member 107 held in the first locking groove 105 of the female member 102 is pushed and expanded by the male member 103, so that the insertion of the male member 103 into the female member 102 is allowed.

[0007] Then, as shown in Fig. 17A, when the second locking groove 115 of the male member 103 aligns with the first locking groove 105 of the female member 102, the elastic ring member 107 that was expanded as shown by the dashed line in Fig. 17A is contracted as shown by the solid line by its own elastic restoring force and fits into and is locked in the second locking groove 115 of the male member 103. Therefore, the female member 102 and the male member 103 are connected to each other via the elastic ring member 107. For this reason, even if fluid pressure acts on the pipe joint 101, the male member 103 is prevented from coming off the female member 102.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, when relative rotation is repeatedly performed between the female member 102 and the male member 103 due to, for example, vibration while fluid pressure is acting on the conventional pipe joint 101 shown in FIG. 16, as shown in FIG. 17B, the contact portion between the corner of the elastic ring member 107 and the second locking groove 115 of the male member 103 is worn away to form a tapered surface, and the two come into surface contact with each other by this tapered surface. At this time, when an upward force in the figure (a force in the direction of pulling out the male member 103) acts on the male member 103 due to fluid pressure, a force f1 perpendicular to the contact surface acts on the tapered surface-like contact surface between the elastic ring member 107 and the second locking groove 115. As shown in FIG. 17B, for this reason, the elastic ring member 107 expands in diameter (expands in the direction of the illustrated arrow) due to the horizontal component force f 11 of this force f1. For this reason, as shown in FIG. 17C, the locking state between the elastic ring member 107 and the second locking groove 115 of the male member 103 is released, and a problem occurs in that the male member 103 comes out upward in the figure.

[0010] The present invention has been made in view of the above problems, and an object thereof is to provide a highly durable pipe joint capable of preventing the male member from coming off from the female member even when relative rotation is repeatedly performed between the female member and the male member due to vibration or the like while fluid pressure is acting, and a method for attaching the pipe joint.

Means for Solving the Problems

[0011] To achieve the above object, a pipe joint according to the present invention includes a cylindrical female member that holds an elastic ring member capable of expanding and contracting in a first locking groove formed on an inner peripheral surface, and a cylindrical shape in which a second locking groove is formed on an outer peripheral surface. The male member is connected to the female member via the elastic ring member by being inserted while expanding the elastic ring member. The elastic ring member is composed of a circular ring having a rectangular cross section in which a part is cut out. A first tapered surface that contracts in diameter toward the opening direction of the female member is provided at an opening side portion of the female member of the first locking groove. Further, a method for attaching a pipe joint according to the present invention is characterized in that after attaching the female member to a device, the male member is connected to the female member.

Effects of the Invention

[0012] According to the present invention, when the male member is inserted into the female member and the elastic ring member is locked to both the first locking groove of the female member and the second locking groove of the male member, the female member and the male member are connected to each other. When fluid pressure acts on the pipe joint, the corner portion of the elastic ring member engages with the first tapered surface of the first engaging groove. The elastic ring member is reduced in diameter by the horizontal component of the force (the force perpendicular to the first tapered surface) acting on the engaging portion of the corner portion of the elastic ring member with the first tapered surface, and the inner peripheral surface of the elastic ring member is pressed against the second locking groove of the male member. As a result, relative rotation between the female member and the male member due to vibration or the like is less likely to occur in a state where fluid pressure is acting, and even if rotation is repeated, the male member is prevented from coming off from the female member.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 6C

Figure 7

Figure 8A

Figure 8B

Figure 8C

Figure 8D

Figure 9A

Figure 9B

Figure 9C

Figure 9D

Figure 9E

Figure 9F

Figure 10A

Figure 10B

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17A

Figure 17B

Figure 17C

Mode for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0015] <First Embodiment> FIG. 1 is a half-section longitudinal sectional view showing a state before fastening of a female member and a male member constituting a pipe joint according to the present embodiment, FIG. 2 is an enlarged detailed view of part A in FIG. 1, FIG. 3 is an enlarged detailed view of part B in FIG. 1, and FIG. 4 is a plan view of an elastic ring member.

[0016] As shown in FIG. 1, the pipe joint 1 of the present embodiment includes an adapter 2 which is a metal female member and a body 3 which is a resin male member. For example, the adapter 2 is connected to a device, and the body 3 is connected to a brake pipe and used.

[0017] In the present embodiment, the adapter 2 is made of a lead-containing copper-zinc alloy (C3604), and the body 3 is made of polyamide 12 (PA12) reinforced with glass fiber (GF). However, these materials are merely examples and are not limited. The material constituting the adapter 2 may be metal or resin. As the metal, brass material, lead-free material such as C6801, aluminum alloy, steel material, and stainless steel material can be used. As the material constituting the body 3, PPA reinforced with GF can be used, but not only resin, but also brass forgings (C3771), brass lead-free materials, aluminum alloys, stainless steel alloys, etc. can be used.

[0018] The above-mentioned adapter 2 is a cylindrical member, and a flow path 4 formed by circular holes 2a and 2b with different diameters is provided through the axial center portion. In this embodiment, the configuration of the circular holes 2a and 2b with different diameters is shown, but this is just an example, and circular holes with the same diameter may also be used. And on the outer periphery of the adapter 2 at the middle height position in the vertical direction of FIG. 1, a nut portion 2A is integrally formed, and a thread portion 2B is engraved on the outer periphery of the lower end portion below the nut portion 2A. Note that the adapter 2 can be attached to the device by turning the nut portion 2A with a tool (not shown) such as a wrench or a spanner and screwing the thread portion 2B into a threaded hole of a device (not shown). Note that the thread shape of the adapter 2 is just an example and is not limited. It may be a tapered thread, a parallel thread, a sealing material, a metal seal, etc. Also, it may be an internal thread. In this embodiment, the configuration having the nut portion 2A is shown, but this is just an example, and it may be a configuration in which an internal hexagonal shape is provided inside the thread of the adapter 2 and it can be attached to the device using a hexagonal wrench. In this case, the outer side may have a cylindrical shape instead of the shape of the nut portion 2A.

[0019] On the upper and lower sides of the inner peripheral surface of the circular hole 2a on the large-diameter side of the adapter 2, a first locking groove 5 with a rectangular cross-section and a ring groove 6 are respectively formed over the entire circumference. In the first locking groove 5, a C-ring 7, which is a resin elastic ring member, is fitted and held, and in the ring groove 6, a ring-shaped O-ring 8, which is a seal member, is fitted. Note that as the material constituting the O-ring 8, for example, ethylene propylene diene rubber (EPDM), acrylonitrile butadiene rubber (NBR), and hydrogenated nitrile rubber (HNBR) can be used. Also, the C-ring 7 is not limited to resin and may be made of metal.

[0020] Here, the above-mentioned first locking groove 5 is formed over the entire circumference in the upper part (on the side of the upper end opening of the adapter 2) in the height direction of the inner peripheral surface of the large-diameter circular hole 2a of the adapter 2. As shown in detail in Fig. 2, a first tapered surface 5a that tapers in diameter toward the opening direction of the adapter 2 is provided at the opening side portion of the first locking groove 5 of the adapter 2. Further, a small inner diameter portion 5b having a smaller inner diameter than the first locking groove 5 is connected to the first tapered surface 5a and provided on the side opposite to the opening direction of the adapter 2. The small inner diameter portion 5b has a surface (vertical surface) parallel to the axial direction of the adapter 2 (the vertical direction in Fig. 2). Further, a second tapered surface 5c that tapers in diameter toward the opening direction of the adapter 2 is connected to the small inner diameter portion 5b and provided on the side opposite to the opening direction of the adapter 2. In this way, two-stage first tapered surface 5a and second tapered surface 5c that taper upward in Fig. 2 are formed at the upper end opening side portion of the adapter 2, and the inner peripheral surface connecting these first tapered surface 5a and second tapered surface 5c constitutes the small inner diameter portion 5b. The bottom surface 5d at the lower end of the first locking groove 5 in Fig. 2 is a ring-shaped flat surface (horizontal surface) parallel to the direction perpendicular to the axis of the adapter 2 (the left-right direction in Fig. 2). The bottom surface 5d and the second tapered surface 5c are connected to each other by a vertical surface 5e parallel to the axial direction of the adapter 2.

[0021] As shown in Fig. 4, a resin C-ring 7 with a partially cut-out outer circumference that can expand and contract in diameter is fitted and held in the first locking groove 5 formed in the adapter 2. Here, the C-ring 7 is a circular ring with a rectangular longitudinal cross-section. When the body 3 is not connected to the adapter 2 (when the C-ring 7 is in the initial state (no-load state)), as shown in Fig. 2, its inner peripheral surface protrudes by ε shown in the figure from the inner peripheral surface of the large-diameter circular hole 2a of the adapter 2, and a gap δ shown in the figure is formed between the outer peripheral surface of the C-ring 7 and the vertical surface 5e of the first locking groove 5. In this embodiment, the C-ring 7 is made of polyamide 12 (PA12) reinforced with glass fiber (GF), which is the same material as the body 3, but is not limited thereto.

[0022] As shown in Fig. 1, the body 3 is a cylindrical member bent in a horizontal L shape, and includes a vertical portion 3A and a horizontal portion 3B that bends at a right angle from the upper end portion of the vertical portion 3A and extends horizontally integrally. A seal ring 9, a back ring 10, a lock ring 11, a lock ring holder 12, and a release ring 13 are provided at the open-side end of the horizontal portion 3B. Further, inside the body 3, a flow path 14 that bends in a horizontal L shape is penetratingly provided by circular holes 3a and 3b having different diameters. In this embodiment, the body 3 is composed of a member bent in a horizontal L shape, but the body 3 may be composed of a T-shaped or Y-shaped member.

[0023] Further, a flange portion 3C is integrally formed at an intermediate height position on the outer periphery of the vertical portion 3A of the body 3, and a portion below the flange portion 3C constitutes an insertion portion 3A1 that is inserted into the adapter 2. A tapered surface 3c that reduces in diameter downward is formed at the outer peripheral edge of the lower end of the insertion portion 3A1. Here, a second locking groove 15 is formed over the entire circumference on the outer peripheral surface of the insertion portion 3A1. In this second locking groove 15, as shown in detail in Fig. 3, a tapered surface 15a that expands in diameter upward is formed at the upper end portion, and the bottom surface 15b at the lower end, which is the end surface on the opening side of the body 3 of the second locking groove 15, is a plane (horizontal plane) perpendicular to the vertical axis of the insertion portion 3A1 of the body 3. Further, the tapered surface 15a and the bottom surface 15b at the lower end of the second locking groove 15 are connected to each other by a vertical surface 15c.

[0024] Next, the connection procedure between the adapter 2 and the body 3 of the pipe joint 1 configured as described above will be described below with reference to Figs. 5 to 7.

[0025] Fig. 5 is a half-section longitudinal sectional view of the pipe joint 1 showing a state where the body 3 is inserted into the adapter 2, Figs. 6A to 6C are enlarged detailed views of part C of Fig. 5 showing the fastening procedure of the pipe joint in the order of the steps, and Fig. 7 is a half-section longitudinal sectional view of the pipe joint 1 showing a state where the body 3 is fastened to the adapter 2.

[0026] The pipe joint 1 of the present embodiment can be used, for example, for air pipes such as vehicle air brake pipes for trucks. The pipe joint 1 of the present embodiment can be attached so that the pipe joints 1 do not interfere with each other even at the clamping pitch by attaching the adapter 2 to the device first using a tool such as a torque driver.

[0027] As shown in FIG. 5, the pipe joint 1 of the present embodiment is used by inserting the insertion portion 3A1 of the body 3 into the adapter 2 fixed vertically to the pipe joint 1 from above.

[0028] As described above, when the insertion portion 3A1 of the body 3 is inserted into the adapter 2 from above, as shown in FIG. 6A, the tapered surface 3c formed on the outer peripheral edge of the lower end of the insertion portion 3A1 of the body 3 abuts against the inner peripheral edge of the upper end of the C-ring 7 fitted and held in the first locking groove 5 of the adapter 2, and the C-ring 7 is pushed and expanded in the direction of the arrow shown in the figure, and the diameter of the C-ring 7 is expanded. Then, as shown in FIG. 6B, the C-ring 7 is buried in the first locking groove 5, allowing the passage (pushing in) of the body 3.

[0029] Then, as shown in FIG. 6C, when the second locking groove 15 of the body 3 aligns with the first locking groove 5 of the adapter 2, the force for expanding the diameter of the C-ring 7 is released, so the C-ring 7 contracts in diameter by its own elastic restoring force and returns to its original initial state, and is locked in the second locking groove 15 of the body 3. As a result, as shown in FIG. 7, the body 3 is connected to the adapter 2 via the C-ring 7 by a simple operation of simply inserting the body 3 into the adapter 2 from above. Therefore, for example, in the limited space inside the bonnet of a truck, the pipe joints 1 can be attached with good workability while preventing interference between the plurality of pipe joints 1.

[0030] Next, the behavior of the C-ring 7 when fluid pressure acts on the pipe joint 1 in which the adapter 2 and the body 3 are fastened by the above procedure will be described below with reference to FIGS. 8A to 8D.

[0031] Figs. 8A to 8D are enlarged cross-sectional views of the main part showing the behavior of the C-ring 7 when fluid pressure acts on the pipe joint 1 according to the present embodiment. When no fluid pressure acts on the pipe joint 1, the C-ring 7 is in the state shown in Fig. 6C. However, when fluid pressure acts on the pipe joint 1, that is, when, for example, high-pressure air flows through the flow path 4 of the adapter 2 and the flow path 14 of the body 3, the body 3 receives a force in the direction of coming off from the adapter 2 (upward in Figs. 8A to 8D). Then, as shown in Fig. 8A, the body 3 moves upward until the corner portion of the outer peripheral edge of the upper end of the C-ring 7 engages with the second tapered surface 5c of the first locking groove 5 at the engagement point p. At the engagement point p of the C-ring 7 with the second tapered surface 5c of the first locking groove 5, the horizontal component force F of the force F1 acting on the C-ring 7 (the force perpendicular to the second tapered surface 5c) 11 causes the C-ring 7 to reduce its diameter.

[0032] Also, the bottom surface 7b of the C-ring 7 is in surface contact with the bottom surface 15b of the second locking groove 15 of the body 3, and an upward vertical reaction force N acts on this contact surface. At this time, if the friction coefficient of the contact surface is μ, a frictional force of μ·N acts on the bottom surface 7b of the C-ring 7. The frictional force μ·N and the horizontal component force F of the force F1 acting at the engagement point p 11 are equal in magnitude and act in opposite directions to each other. Therefore, a couple M in the arrow direction (clockwise direction) (see Fig. 8B) acts on the C-ring 7, and when the corner portion of this C-ring 7 reaches the end of the second tapered surface 5c of the first locking groove 5 as shown in Fig. 8B, the C-ring 7 tilts due to the couple M.

[0033] And when the engagement point p of the corner portion of the C-ring 7 comes off from the second tapered surface 5c of the first locking groove 5, as shown in Fig. 8C, the upper end portion of the C-ring 7 enters the space S formed between the small inner diameter portion 5b of the first locking groove 5 and the vertical surface 15c of the second locking groove 15, and its corner portion engages with the first tapered surface 5a of the first locking groove 5 at the engagement point q. At this time, the width w of the space S formed between the small inner diameter portion 5b of the first locking groove 5 and the vertical surface 15c of the second locking groove 15 is larger than the thickness t of the C-ring 7 (w>t), and the upper end portion of the C-ring 7 enters the space S. Therefore, the fall of the C-ring 7 is restricted by the small inner diameter portion 5b of the first locking groove 5 and is suppressed to be small.

[0034] In this state, the C-ring 7 and the body 3 can move upward (the direction in which the body 3 comes off) until the corner of the C-ring 7 engages with the first tapered surface 5a of the first locking groove 5 at the engagement point q as shown in FIG. 8C, and further movement, that is, the removal of the body 3 from the adapter 2 is prevented. At this time, since a force F2 perpendicular to the first tapered surface 5a acts on the engagement point q of the corner of the C-ring 7 with the first tapered surface 5a, the horizontal component force F of this force F2 21 causes the C-ring 7 to reduce its diameter, and its inner peripheral surface is pressed against the vertical surface 15c of the second locking groove 15 of the body 3. For this reason, the engagement margin ε2 of the C-ring 7 with the bottom surface 15b of the second locking groove 15 becomes larger than the engagement margin ε1 shown in FIG. 8A (ε2>ε1), and the removal of the body 3 from the adapter 2 is further prevented. Therefore, even if relative rotation between the adapter 2 and the body 3 is repeated due to vibration or the like while fluid pressure such as air pressure is acting, the body 3 is prevented from coming off the adapter 2, and the durability of the pipe joint 1 against rotation is enhanced.

[0035] And, since relative rotation between the adapter 2 and the body 3 is repeated due to vibration or the like while fluid pressure is acting, as shown in FIG. 8D, even when the corner of the C-ring 7 is worn by rubbing against the second tapered surface 5c of the first locking groove 5 to form a tapered surface 7a, the C-ring 7 is pressed in the diameter-reducing direction by the horizontal component force F of the force F3 perpendicular to the first tapered surface 5a of the first locking groove 5. As a result, since the inner peripheral surface of the C-ring 7 is pressed against the vertical surface 15c of the second locking groove 15, a sufficient engagement margin ε3 of the C-ring 7 with the second locking groove 15 is ensured, and even when fluid pressure acts on the pipe joint 1, the body 3 is prevented from coming off the adapter 2. 31 As a result, the C-ring 7 is pressed in the diameter-reducing direction by the horizontal component force F of the force F3 perpendicular to the first tapered surface 5a of the first locking groove 5. As a result, since the inner peripheral surface of the C-ring 7 is pressed against the vertical surface 15c of the second locking groove 15, a sufficient engagement margin ε3 of the C-ring 7 with the second locking groove 15 is ensured, and even when fluid pressure acts on the pipe joint 1, the body 3 is prevented from coming off the adapter 2.

[0036] Here, another form of the C-ring 7 is shown in FIGS. 9A to 9F. As shown in FIG. 9A, the corner of the outer peripheral edge of the upper end (one axial end) of the C-ring 7 may be cut obliquely, and this portion may be used as the tapered surface 7c. In this case, since there is a possibility of incorrect assembly in which the C-ring 7 is assembled upside down when assembling the pipe joint 1, as shown in FIG. 9B, both corners of the outer peripheral edge of the upper and lower parts (both axial ends) of the C-ring 7 may be cut obliquely and this portion may be used as the tapered surface 7c respectively. Alternatively, as shown in FIG. 9C, a tapered surface 7c may be formed at the corner of the inner peripheral edge of the upper end of the C-ring 7, and as shown in FIG. 9D, tapered surfaces 7c may be formed at the respective corners of the inner and outer peripheral edges of the upper end of the C-ring 7. Or, as shown in FIG. 9E, tapered surfaces 7c may be formed at the respective corners of the inner peripheral edge of the upper end and the outer peripheral edge of the lower end of the C-ring 7, and as shown in FIG. 9F, tapered surfaces 7c may be formed at the respective corners of the inner and outer peripheral edges of the upper end and the outer peripheral edge of the lower end of the C-ring 7 excluding the inner peripheral edge of the lower end.

[0037] According to the pipe joint 1 of the present embodiment, the horizontal components F of the forces F2 and F3 (the forces perpendicular to the first tapered surface 5a) acting on the engaging portion of the corner of the C-ring 7 with the first tapered surface 5a 21 ,F 31 cause the C-ring 7 to contract in diameter, and the inner peripheral surface of the C-ring 7 is pressed against the second locking groove 15 of the body 3. As a result, even if the relative rotation between the adapter 2 and the body 3 is repeated due to vibration or the like while the fluid pressure is acting, the body 3 is prevented from coming off from the adapter 2, and the durability of the pipe joint 1 against rotation is enhanced.

[0038] Also, according to the pipe joint 1 of the present embodiment, the frictional force at the contact surface between the C-ring 7 and the body 3 is reduced, whereby the amount of wear at the contact surface between the C-ring 7 and the body 3 is reduced, and the body 3 can be prevented from coming off from the adapter 2.

[0039] <Second Embodiment> In the pipe joint of the present embodiment, the configuration of the first locking groove 205 is different from that of the first embodiment as described below, but except for this point, the configuration is the same as that of the first embodiment.

[0040] FIG. 10A and FIG. 10B are enlarged cross-sectional views of the main part showing the behavior of the C-ring when fluid pressure acts on the pipe joint according to the present embodiment.

[0041] As shown in FIG. 10A, a first tapered surface 205a that tapers in diameter toward the opening direction of the adapter 202 is provided at the opening side portion of the adapter 202 of the first locking groove 205. The bottom surface 205d at the lower end of the first locking groove 205 in FIG. 10A is a ring-shaped flat surface (horizontal plane) parallel to the direction perpendicular to the axis of the adapter 202 (the left-right direction in FIG. 10A). The bottom surface 205d and the first tapered surface 205a are connected to each other by a vertical surface 205e parallel to the axial direction of the adapter 202.

[0042] In the pipe joint having the locking structure as described above, as shown in FIG. 10A, in a state where the adapter 202 and the body 203 are connected, the C-ring 207 is locked to both the first locking groove 205 of the adapter 202 and the second locking groove 215 of the body 203 to prevent the body 203 from coming off the adapter 202.

[0043] When fluid pressure acts on the pipe joint and the body 203 receives a force in the direction of coming off the adapter 202 (upward in FIG. 10A), as shown in FIG. 10B, the corner portion of the C-ring 207 contacts the tapered surface 205a of the first locking groove 205 formed in the adapter 202 at the engagement point a and contacts the second locking groove 215 formed in the body 203 at the engagement point b. At this time, a force f2 perpendicular to the tapered surface 205a of the first locking groove 205 acts on the engagement point a.

[0044] According to the pipe joint of the present embodiment, the horizontal component f of the force f (the force in the direction perpendicular to the tapered surface 205a) acting on the engaging portion of the corner of the C-ring 207 with the tapered surface 205a causes the C-ring 207 to contract in diameter, and the inner peripheral surface of the C-ring 207 is pressed against the second locking groove 215 of the body 203. As a result, even if the relative rotation between the adapter 202 and the body 203 is repeated due to vibration or the like while the fluid pressure is acting, the body 203 is prevented from coming off the adapter 202, and the durability of the pipe joint against rotation is enhanced. 21 causes the C-ring 207 to contract in diameter, and the inner peripheral surface of the C-ring 207 is pressed against the second locking groove 215 of the body 203. As a result, even if the relative rotation between the adapter 202 and the body 203 is repeated due to vibration or the like while the fluid pressure is acting, the body 203 is prevented from coming off the adapter 202, and the durability of the pipe joint against rotation is enhanced.

[0045] Note that an upward vertical resistance N acts on the engagement point b between the corner of the C-ring 207 and the bottom surface 215b of the second locking groove 215. If the coefficient of friction at the engagement point b is μ, a frictional force μ·N in the direction of the illustrated arrow acts on this engagement point b. Therefore, the horizontal component f of the force f2 21 and the frictional force μ·N act on the C-ring 207 to produce a clockwise couple in Fig. 10B. Due to this couple, the C-ring 207 may fall inside the first locking groove 205 and the second locking groove 215, and the engagement allowance (engagement margin) of the C-ring 207 with the second locking groove 215 at the engagement point b may become smaller. In this case, as shown in the first embodiment, by providing a small inner diameter portion in the first locking groove 205 and configuring the C-ring 207 to enter the space between the first locking groove 205 and the second locking groove 215, the fall of the C-ring 207 can be restricted and suppressed to a small extent by the small inner diameter portion of the first locking groove 205.

[0046] Note that the present invention is not limited to the embodiments described above, and it goes without saying that various modifications are possible within the scope of the technical idea described in the claims, the specification, and the drawings. For example, the second tapered surface may be a surface parallel to the direction perpendicular to the axis of the adapter, that is, a surface parallel to the bottom surface of the lower end of the first locking groove. Also, conversely to the above embodiments, the adapter may be a male member and the body may be a female member. Furthermore, a pipe joint having a plurality of female members and male members respectively may also be possible.

[0047] Here, various modification examples of the pipe joint according to the present invention will be described below with reference to Figs. 11 to 15.

[0048] <Modification Example 1> Figure 11 is a half-section longitudinal sectional view showing the state before fastening of the female member and the male member of the pipe joint according to Modification 1 of the present invention. In the pipe joint 1A according to this modification, the female member and the male member are reversed with respect to the pipe joint 1 (see FIG. 1) according to the first embodiment. That is, the body 3, which is the male member disposed below the adapter 2, which is the female member disposed above in FIG. 11, is inserted, and the adapter 2 and the body 3 are easily connected in one touch. In practice, after the body 3 is fastened to a device (not shown) using a tool (not shown), the body 3 is inserted into the adapter 2 from below and the two are connected.

[0049] Here, in FIG. 11, the same reference numerals are given to the same elements as those shown in FIG. 1. In the adapter 2, the C-ring 7 is fitted and held in the first locking groove 5, and the O-ring 8 is fitted in the ring groove 6. Further, in the body 3, a second locking groove 15 is formed on the outer periphery of the insertion portion 3A1.

[0050] Since the basic configuration of the pipe joint 1A according to this modification configured as described above is the same as that of the pipe joint 1 (see FIG. 1) according to the first embodiment, the same effects as those obtained in the first embodiment can also be obtained in the pipe joint 1A according to this modification.

[0051] <Modification 2> Figure 12 is a half-section longitudinal sectional view of the female member of the pipe joint according to Modification 2 of the present invention. In this modification, an O-ring 17 for preventing foreign matter is fitted in a ring groove 16 formed over the entire circumference on the inner peripheral portion of the upper end of the adapter 2, which is the female member, and the other configuration is the same as that of the adapter 2 (see FIG. 1) according to the first embodiment. Therefore, in FIG. 12, the same reference numerals are given to the same elements as those shown in FIG. 1.

[0052] <Modification 3> Figure 13 is a semi-longitudinal sectional view of the female member of the pipe joint according to Modification 3 of the present invention. In this modification, a circular hole 2c with the same diameter penetrates through the axial center of the adapter 2, which is the female member. A C-ring 7 and an O-ring 8 are respectively fitted and held in the first locking groove 5 and the ring groove 6 formed above and below the circular hole 2c. Further, an O-ring 18 is fitted on the outer periphery between the nut portion 2A and the screw portion 2B in the height direction (vertical direction). Other configurations are the same as those of the adapter 2 (see FIG. 1) according to the first embodiment. Therefore, in FIG. 13, the same reference numerals are given to the same elements as those shown in FIG. 1.

[0053] <Modification 4> Figure 14 is a semi-longitudinal sectional view of the female member of the pipe joint according to Modification 4 of the present invention. In this modification, in the adapter 2 according to Modification 3, an O-ring 17 for preventing foreign matter is fitted in the ring groove 16 formed at the upper end of the circular hole 2c, and other configurations are the same as those shown in Modification 3 (see FIG. 13).

[0054] <Modification 5> Figure 15 is a semi-longitudinal sectional view of the female member of the pipe joint according to Modification 5 of the present invention. In this modification, the adapter 2 is configured as a T-shaped tubular member, and three openings (two upper and lower and one on the side) are formed in the adapter 2. A C-ring 7 and an O-ring 8 are respectively fitted in each of the three openings.

[0055] Therefore, an elbow-shaped or Y-shaped body (not shown) can be inserted and connected to the adapter 2 from three directions.

[0056] <Method of attaching the pipe joint> For the pipe joints of the above-described embodiments and modifications, for example, after attaching the adapter 2 to the equipment, the body 3 is connected to the adapter 2 and then attached.

Explanation of reference numerals

[0057] 1 Pipe joint 2 Adapter (female member) 3 Body (male member) 5 First locking groove 5a First tapered surface of the first locking groove 5b Small inner diameter part of the first locking groove 5c Second tapered surface of the first locking groove 5d Bottom surface of the first locking groove 5e Vertical surface of the first locking groove 7 C-ring 7a Tapered surface of the C-ring 7b Bottom surface of the C-ring 7c Tapered surface of the C-ring 15 Second locking groove 15a Tapered surface of the second locking groove 15b Bottom surface of the second locking groove 15c Vertical surface of the second locking groove

Claims

1. A cylindrical female member that holds an elastic ring member capable of expanding and contracting in a first locking groove formed on an inner peripheral surface, A cylindrical male member having a second locking groove formed on an outer peripheral surface, and being connected to the female member via the elastic ring member by being inserted while expanding the elastic ring member, comprising: The elastic ring member is composed of a circular ring having a rectangular longitudinal section with a part cut out, A first tapered surface that contracts in diameter toward the opening direction of the female member is provided at an opening side portion of the female member of the first locking groove, A small inner diameter portion having an inner diameter smaller than that of the first locking groove is connected to the first tapered surface and provided on the opposite side of the opening direction of the female member, A second tapered surface that contracts in diameter toward the opening direction of the female member is connected to the small inner diameter portion and provided on the opposite side of the opening direction of the female member, An end surface on the opposite side of the opening direction of the female member of the first locking groove is composed of a plane perpendicular to the axial direction of the female member, The end surface of the first locking groove and the second tapered surface are connected to each other by a surface parallel to the axial direction of the female member, In the female member, the elastic ring member is held in the first locking groove such that a corner portion of an outer peripheral edge portion at one axial end of the elastic ring member faces the second tapered surface in the axial direction of the female member, When the male member and the female member are fastened and a fluid pressure acts in a state where the elastic ring member is locked in both the first locking groove and the second locking groove and the male member receives a force in a direction of coming off from the female member, the corner portion of the elastic ring member and the second tapered surface facing each other are engaged, and the elastic ring member is contracted in diameter by a horizontal component of a force in a direction perpendicular to the second tapered surface acting on an engagement point between the corner portion of the elastic ring member and the second tapered surface, When the corner of the elastic ring member disengages from the second tapered surface due to a reduction in the diameter of the elastic ring member, the corner of the elastic ring member enters the space formed between the small inner diameter portion and the second locking groove, so that the corner of the elastic ring member engages with the first tapered surface. The elastic ring member is reduced in diameter by the horizontal component of the force perpendicular to the first tapered surface acting on the engagement point between the corner of the elastic ring member and the first tapered surface, and the inner peripheral surface of the elastic ring member is pressed against the second locking groove. Pipe joint.

2. The small inner diameter portion has a surface parallel to the axial direction of the female member. The pipe joint according to claim 1.

3. The end surface of the male member on the opening side of the second locking groove is composed of a plane perpendicular to the axial direction of the insertion portion of the male member into the female member. The pipe joint according to claim 1 or 2.

4. A tapered surface is provided at the outer peripheral edge of one end in the axial direction or at the outer peripheral edges of both ends in the axial direction of the elastic ring member. The pipe joint according to any one of claims 1 to 3.

5. A method for installing the pipe joint according to any one of claims 1 to 4, After attaching the female member to the equipment, connect the male member to the female member. Method for installing a pipe joint.

Images