Pipe fittings

Abstract

The present invention provides a pipe fitting that can prevent the valve from opening due to negative pressure when no tube is inserted, while suppressing an increase in size. [Solution] A pipe joint 10 comprising a cylindrical body 11 having an inner diameter portion 51 into which a tube 96 is inserted, a bottomed cylindrical valve 18 provided on the inner diameter portion 51 of the body so as to be movable in the insertion direction A and the disengagement direction B of the tube 96, and a cylindrical spring 19 provided on the inner diameter portion 51 of the body so as to bias the valve 18 in the disengagement direction B, wherein the pipe joint 10 comprises a spring guide 20 that supports the spring 19, the spring guide 20 having a spring-side support portion 86 inserted into the inner diameter portion 81 of the spring, a valve-side support portion 87 inserted into the inner diameter portion 69 of the valve, and a flange portion 88 provided between the spring-side support portion 86 and the valve-side support portion 87, protruding radially outward and sandwiched between the spring 19 and the valve 18.

Description

Technical Field

[0001] The present invention relates to a pipe joint.

Background Art

[0002] A pipe joint for connecting tubes is known (for example, Patent Document 1). The pipe joint disclosed in Patent Document 1 includes a joint body, a valve body provided movably between a primary side and a secondary side inside the joint body, and a spring provided inside the joint body to urge the valve body toward the secondary side. The pipe joint disclosed in Patent Document 1 is configured such that the flow path is blocked when the valve body moves to the secondary side (i.e., the valve body closes) by the spring, and the flow path is opened when the valve moves to the primary side (i.e., the valve body opens) by inserting the tube.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the pipe joint disclosed in Patent Document 1 has a problem that when negative pressure is supplied into the joint body in a state where no tube is inserted, the valve body opens due to the contraction of the spring and the flow path is opened. Although a method of increasing the strength of the spring by increasing the spring constant of the spring to suppress the contraction of the spring can be considered, an increase in the spring wire diameter for increasing the spring constant leads to an increase in the size of the spring, and as a result, the size of the pipe joint increases.

[0005] An object of the present invention is to provide a pipe joint that suppresses an increase in size and prevents the valve from being opened by negative pressure in a state where no tube is inserted.

Means for Solving the Problems

[0006] The pipe fitting according to the present invention comprises a cylindrical body having an inner diameter portion into which a tube is inserted, a bottomed cylindrical valve provided in the inner diameter portion of the body so as to be movable in the direction of insertion of the tube and in a direction of disengagement opposite to the insertion direction, and a cylindrical spring provided in the inner diameter portion of the body so as to bias the valve in the disengagement direction, wherein the flow path formed by the inner diameter portion of the body is closed when the valve is moved in the disengagement direction by the spring, and the flow path is opened when the valve is moved in the insertion direction by the insertion of the tube into the inner diameter portion of the body, and further comprises a spring guide that supports the spring, the spring guide having a spring-side support portion inserted into the inner diameter portion of the spring, a valve-side support portion inserted into the inner diameter portion of the valve, and a flange portion provided between the spring-side support portion and the valve-side support portion and protruding radially outward, sandwiched between the spring and the valve. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a pipe fitting that can prevent the valve from opening due to negative pressure when a tube is not inserted, while suppressing an increase in size. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view of a pipe fitting, showing the state before a tube is inserted. [Figure 2] This is a perspective view of a pipe fitting, with a portion of the body cut away to show the inside of the body. [Figure 3] This is a cross-sectional view of a pipe fitting, showing the state in which a tube is inserted. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described in detail below with reference to the drawings. The embodiments shown below are examples of the present invention, and the present invention is not limited thereto.

[0010] <Pipe joint configuration> Figure 1 is a cross-sectional view of the pipe fitting 10, showing the state without a tube inserted. The pipe fitting 10 is used to connect tubes through which various fluids such as liquids and gases flow. The type of tube connected to the pipe fitting 10 is arbitrary; for example, nylon resin tubes, urethane resin tubes, polyester resin tubes, polyolefin resin tubes, fluororesin tubes, etc., can be used.

[0011] In Figure 1, the pipe fitting 10 comprises a body 11, a collar 12, a lock ring 13, a back ring 14, a spacer 15, a tube seal 16, a valve stop 17, a valve 18, a spring 19, a spring guide 20, a release sleeve 21, and a gasket 22.

[0012] Body 11 is a cylindrical member. Body 11 is made of metal or an alloy. In the pipe fitting 10, equipment such as the vehicle's cooling circuit is connected to the base end of body 11, and a tube is connected to the tip end of body 11. In the pipe fitting 10, the direction in which the tube is inserted is called the insertion direction A, and the direction in which the tube is removed, opposite to the insertion direction, is called the removal direction B. The end on the insertion direction A side is called the base end, and the end on the removal direction B side is called the tip end. The radial direction is defined as the direction radiating from the central axis CL of body 11, and the direction around the central axis CL of body 11 is called the circumferential direction.

[0013] The outer circumferential surface of the body 11 has a tool engagement portion 31, a straight portion 32 provided on the side of the tool engagement portion 31 in the disengagement direction B, and a connecting portion 33 provided on the side of the tool engagement portion 31 in the insertion direction A. The tool engagement portion 31, the straight portion 32, and the connecting portion 33 are integrally formed.

[0014] The tool engagement portion 31 engages with tools such as spanners and wrenches. In this embodiment, the external shape of the tool engagement portion 31 is hexagonal. However, the external shape of the tool engagement portion 31 is not limited to hexagonal; it may be various shapes that allow tools to engage, such as polygons like squares and octagons, or rectangles with rounded corners.

[0015] The straight section 32 is connected to the tool engagement section 31 and extends toward the release direction B. A crimping section 36 is provided at the tip of the straight section 32. The crimping section 36 is the part whose diameter has been reduced by crimping. In this embodiment, the outer shape of the straight section 32 is circular. However, the outer shape of the straight section 32 is not limited to a circular shape, and may be various shapes such as a rectangle with rounded corners, a quadrilateral or hexagon, or other polygons.

[0016] The connecting portion 33 is connected to the tool engagement portion 31 and extends toward the insertion direction A. The connecting portion 33 has a male thread 37 that screws into the female thread formed on the equipment. The pipe fitting 10 is connected to the equipment by the male thread 37 of the connecting portion 33 screwing into the female thread of the equipment.

[0017] The body 11 has a base end opening 41 provided at the base end, a tip end opening 42 provided at the tip end, and a body inner diameter portion 51 connecting the base end opening 41 and the tip end opening 42. The base end opening 41 and the tip end opening 42 are positioned on the central axis CL. The base end opening 41 and the tip end opening 42 are circular. The body inner diameter portion 51 extends along the central axis CL. The inner circumferential surface of the body inner diameter portion 51 is a cylindrical surface.

[0018] A tube is inserted into the inner diameter portion 51 of the body via a tip opening 42. That is, the body 11 has an inner diameter portion 51 into which the tube is inserted. Fluid flows from the tube into the inner diameter portion 51 of the body. The inner diameter portion 51 of the body constitutes a flow path 52 through which the fluid flows.

[0019] The body's inner diameter portion 51 has, in order from the disengagement direction B to the insertion direction A, a first inner diameter portion 51a, a second inner diameter portion 51b, a third inner diameter portion 51c, a fourth inner diameter portion 51d, a fifth inner diameter portion 51e, and a sixth inner diameter portion 51f.

[0020] The first inner diameter portion 51a is connected to the tip opening 42 provided at the tip of the body 11. When the tube is inserted, the first inner diameter portion 51a communicates with the flow path inside the tube through the tip opening 42.

[0021] The second inner diameter portion 51b communicates with the first inner diameter portion 51a. The inner diameter of the second inner diameter portion 51b is smaller than the inner diameter of the first inner diameter portion 51a.

[0022] The third inner diameter portion 51c communicates with the second inner diameter portion 51b. The inner diameter of the third inner diameter portion 51c is smaller than the inner diameter of the second inner diameter portion 51b.

[0023] The fourth inner diameter portion 51d communicates with the third inner diameter portion 51c. The inner diameter of the fourth inner diameter portion 51d is larger than the inner diameter of the third inner diameter portion 51c.

[0024] The fifth inner diameter portion 51e communicates with the fourth inner diameter portion 51d. The inner diameter of the fifth inner diameter portion 51e is smaller than the inner diameter of the fourth inner diameter portion 51d. Also, the inner diameter of the fifth inner diameter portion 51e is smaller than the inner diameter of the third inner diameter portion 51c.

[0025] The sixth inner diameter portion 51f communicates with the fifth inner diameter portion 51e. The inner diameter of the sixth inner diameter portion 51f is smaller than the inner diameter of the fifth inner diameter portion 51e.

[0026] The sixth inner diameter portion 51f is connected to the base end opening 41 provided at the base end of the body 11. When the connecting portion 33 is connected to the device, the sixth inner diameter portion 51f communicates with the flow path inside the device through the base end opening 41.

[0027] The pipe joint 10 has a configuration in which a collar 12, a lock ring 13, a back ring 14, a spacer 15, a tube seal 16, a valve stop 17, a valve 18, a spring 19, and a spring guide 20 are accommodated in the body inner diameter portion 51, and is further composed of a release sleeve 21 and a gasket 22.

[0028] The collar 12 is provided in the first inner diameter portion 51a. The collar 12 is a cylindrical member. The collar 12 is made of metal or an alloy. The collar 12 is fixed to the first inner diameter portion 51a by crimping a crimping portion 36 provided at the tip of the straight portion 32 of the body 11. A lock ring 13 and a back ring 14 are provided inside the collar 12.

[0029] The lock ring 13 is an annular component. The lock ring 13 is made of metal or an alloy. The lock ring 13 restricts the movement of the inserted tube in the direction of withdrawal B.

[0030] An example of the configuration of the lock ring 13 is described below. The lock ring 13 has a plurality of claws arranged in an annular shape and a connecting portion that connects adjacent claws in the circumferential direction. The claws are inclined with respect to the central axis CL such that they move toward the insertion direction A as they move radially inward. The connecting portion is located radially outward from the claws. The lock ring 13 is a zigzag-shaped annular member in which the claws are arranged radially inward and the connecting portion is arranged radially outward.

[0031] When the tube is not inserted into the lock ring 13, the inner diameter of the lock ring 13 is smaller than the outer diameter of the tube. The inner diameter of the lock ring 13 is the diameter of a virtual circle formed by connecting the radially inward inner edges of the multiple claws. When the tube is inserted into the lock ring 13, the multiple claws are pushed in the insertion direction A by the tube, and the inner diameter of the lock ring 13 increases. When the tube is inserted into the lock ring 13, a restoring force is generated in the lock ring 13, and the claws come into contact with the tube radially inward. If the tube is pulled in the release direction B to remove it from the lock ring 13, the claws of the lock ring 13 bite into the tube. Therefore, it is possible to prevent the tube from being removed from the lock ring 13.

[0032] The tube is held in place by the lock ring 13 and can be released using the release sleeve 21. The release sleeve 21 is located inside the collar 12 on the side of the release direction B relative to the lock ring 13. When the release sleeve 21 is moved toward the insertion direction A, it pushes the multiple claws of the lock ring 13 toward the insertion direction A. As the multiple claws are pushed toward the insertion direction A by the release sleeve 21, the inner diameter of the lock ring 13 increases. The multiple claws separate from the tube. In this state, even if the tube is pulled toward the release direction B, the claws of the lock ring 13 will not bite into the tube. Therefore, the tube can be removed from the lock ring 13.

[0033] The buckling ring 14 is provided on the insertion direction A side of the locking ring 13. The buckling ring 14 is a cylindrical member. The buckling ring 14 is made of metal or an alloy. The buckling ring 14 restricts the movement of the locking ring 13 toward the insertion direction A side.

[0034] An example of the configuration of the buckling ring 14 is described below. The buckling ring 14 has a ring body with a roughly triangular cross-sectional shape along the central axis CL, and a projection that protrudes from the ring body toward the detachment direction B and contacts the locking ring 13. When the crimping portion 34 provided at the base end of the collar 12 is crimped, the ring body of the buckling ring 14 is pushed toward the detachment direction B, and the projection pushes the connecting portion of the locking ring 13. The connecting portion of the locking ring 13 is pressed against a stepped portion provided inside the collar 12. As a result, the locking ring 13 and the buckling ring 14 are fixed inside the collar 12.

[0035] Spacer 15 is provided in the second inner diameter portion 51b. Spacer 15 is a cylindrical member. Spacer 15 is made of metal or an alloy. The inner circumferential surface of spacer 15 has a tapered surface in which the diameter decreases sequentially toward the insertion direction A, from the disengagement direction B toward the insertion direction A, and a circumferential surface extending along the central axis CL. The outer edge of the open end of the tube is inserted while in contact with the tapered surface of spacer 15, thereby positioning the tube in a plane perpendicular to the central axis CL.

[0036] The tube seal 16 is provided in the third inner diameter portion 51c. The tube seal 16 is an annular member. The tube seal 16 is made of an elastic material such as rubber. Although the tube seal 16 has a unique shape, O-rings and the like can also be used. The tube seal 16 is in close contact with the third inner diameter portion 51c, the spacer 15, and the valve stop 17. The tube seal 16 is sandwiched between the spacer 15 and the valve stop 17, and its movement in the insertion direction A and the disengagement direction B is restricted.

[0037] When the tube is not inserted, the tube seal 16 and the sealing portion 67 of the valve 18 (described later) come into contact, closing the flow path 52. When the tube is inserted, the valve 18 is pushed by the tube and moves in the insertion direction A, the sealing portion 67 of the valve 18 separates from the tube seal 16, the outer surface of the tube comes into contact with the tube seal 16, the flow path 52 is opened and communicates with the flow path inside the tube. When the tube is pulled out, the valve 18 moves in the withdrawal direction B, the sealing portion 67 of the valve 18 comes into contact with the tube seal 16, closing the flow path 52.

[0038] The valve stop 17 is provided in the fourth inner diameter portion 51d. The valve stop 17 is an annular member. The valve stop 17 is formed in a C-shape, for example, by forming a notch in a part of the circumferential direction of the annular member, and is configured to elastically deform and reduce in diameter when force is applied from the radially outer side. The valve stop 17 is made of a resin that has high strength and high elasticity, such as polyacetal.

[0039] The valve stop 17 is positioned in a recess formed by the fourth inner diameter portion 51d, the stepped portion between the third inner diameter portion 51c and the fourth inner diameter portion 51d, and the stepped portion between the fourth inner diameter portion 51d and the fifth inner diameter portion 51e, and its movement in the insertion direction A and the disengagement direction B is restricted. The valve stop 17 restricts the movement of the valve 18, which is biased by the spring 19, in the disengagement direction B.

[0040] The valve 18 is provided in the second inner diameter portion 51b to the fifth inner diameter portion 51e so as to be movable in the insertion direction A and the disengagement direction B. That is, the valve 18 is provided in the inner diameter portion 51 of the body so as to be movable in the insertion direction A and the disengagement direction B. The valve 18 is a bottomed cylindrical member. The valve 18 is made of a resin having high strength and high elasticity, such as polyacetal.

[0041] The valve 18 has a cylindrical base 66, a sealing portion 67 that contacts the tube seal 16, and a tip portion 68 that contacts the tube.

[0042] The base portion 66 is configured to move within the fifth inner diameter portion 51e in the insertion direction A and the disengagement direction B. The outer circumferential surface of the base portion 66 is cylindrical. The outer diameter of the base portion 66 is slightly smaller than the inner diameter of the fifth inner diameter portion 51e. The valve 18 moves within the fifth inner diameter portion 51e with the outer circumferential surface of the base portion 66 sliding along the inner circumferential surface of the fifth inner diameter portion 51e.

[0043] The base 66 contacts the valve stop 17. The valve 18's movement in the detachment direction B is restricted by the contact of the base 66 with the valve stop 17.

[0044] The base portion 66 has a valve inner diameter portion 69. The valve inner diameter portion 69 extends along the central axis CL. The inner circumferential surface of the valve inner diameter portion 69 is a cylindrical surface.

[0045] The seal portion 67 is positioned on the side of the base portion 66 in the detachment direction B and radially inward, and is connected to the base portion 66. The seal portion 67 is configured to move within the third inner diameter portion 51c to the fifth inner diameter portion 51e in the insertion direction A and the detachment direction B as the base portion 66 moves.

[0046] The outer circumferential surface of the seal portion 67 is composed of a cylindrical surface centered on the central axis CL, a curved surface connected to the cylindrical surface whose diameter decreases toward the release direction B, and a tip surface connected to the curved surface which is perpendicular to the central axis CL. The outer circumferential surface of the seal portion 67 may also have a tapered surface that decreases in diameter toward the release direction B instead of the curved surface.

[0047] An opening 71 is provided in the connection portion between the base portion 66 and the seal portion 67, extending radially through it. The opening 71 communicates with the inner diameter portion 69 of the valve. In this embodiment, three openings 71 are arranged at equal intervals in the circumferential direction. The number of openings 71 is not limited to three; one or more may be used.

[0048] The tip portion 68 is connected to the tip surface of the sealing portion 67. The tip portion 68 is configured to move within the second inner diameter portion 51b to the fifth inner diameter portion 51e in the insertion direction A and the disengagement direction B as the base portion 66 moves.

[0049] An example of the configuration of the tip section 68 will be explained using Figure 2. Figure 2 is a perspective view of the pipe fitting 10, showing the inside of the body 11 by cutting a part of the body 11. In Figure 2, components other than the body 11, valve 18, and spring guide 20 (i.e., collar 12, lock ring 13, back ring 14, spacer 15, tube seal 16, valve stop 17, spring 19, release sleeve 21, and gasket 22) are omitted.

[0050] As shown in Figure 2, the tip portion 68 has a plurality of projections 76 that protrude from the tip surface of the seal portion 67 toward the detachment direction B and are spaced apart in the circumferential direction, and a reinforcing portion 77 that protrudes from the tip surface of the seal portion 67 toward the detachment direction B and is connected to the plurality of projections 76.

[0051] Each projection 76 has a roughly arc-shaped cross-section perpendicular to the central axis CL. The diameter of the virtual circle formed by connecting the radially outer edges of the multiple projections 76 is larger than the inner diameter of the opening end of the tube. The multiple projections 76 abut against the opening end of the inserted tube.

[0052] The reinforcing portion 77 is composed of multiple reinforcing pieces that protrude from the tip surface of the sealing portion 67 toward the detachment direction B. Each reinforcing piece is plate-shaped and is spaced apart in the circumferential direction. The multiple reinforcing pieces are connected to each other on the central axis CL and extend radially outward from the central axis CL, connecting to multiple projections 76.

[0053] In this embodiment, the tip portion 68 has three projections 76 arranged at equal intervals in the circumferential direction, and the three projections 76 are connected by a reinforcing portion 77 with a Y-shaped cross-sectional shape perpendicular to the central axis CL. The shape and number of projections 76 and the shape and number of reinforcing portions 77 are not particularly limited.

[0054] The spring 19 is installed in the inner diameter portion 51 (fifth inner diameter portion 51e) of the body to bias the valve 18 toward the detachment direction B (see Figure 1). The outer diameter of the spring 19 is smaller than the inner diameter of the fifth inner diameter portion 51e and larger than the inner diameter of the sixth inner diameter portion 51f. The spring 19 is a compression coil spring. The spring 19 is made of metal or an alloy. The spring constant of the spring 19 is set to a desired value by adjusting the wire diameter, coil diameter, number of turns, and free length (free height).

[0055] The spring 19 has an inner diameter portion 81. The inner diameter portion 81 extends along the central axis CL. The inner diameter of the inner diameter portion 81 is the same as the inner diameter of the inner diameter portion 69 of the valve. "Same" does not mean strictly identical, but includes "approximately identical".

[0056] The spring guide 20 is configured to support the spring 19 (see Figure 1). The spring guide 20 has a spring-side support portion 86 that is inserted into the inner diameter portion 81 of the spring 19, a valve-side support portion 87 that is inserted into the inner diameter portion 69 of the valve 18, and a flange portion 88 that is provided between the spring-side support portion 86 and the valve-side support portion 87, protruding radially outward and sandwiched between the spring 19 and the valve 18.

[0057] The spring-side support portion 86 is a cylindrical member. The outer surface of the spring-side support portion 86 is a cylindrical surface. The outer diameter of the spring-side support portion 86 is smaller than the inner diameter of the spring inner diameter portion 81. The spring-side support portion 86 is loosely fitted into the spring inner diameter portion 81.

[0058] The outer diameter of the spring-side support portion 86 is larger than the inner diameter of the sixth inner diameter portion 51f. The spring-side support portion 86 contacts the contact portion 91 formed between the fifth inner diameter portion 51e and the sixth inner diameter portion 51f. The contact portion 91 is composed of a plane perpendicular to the central axis CL. When the valve-side support portion 87 and the contact portion 91 are in contact, the height of the spring 19 is greater than the compressed height of the spring 19. The compressed height refers to the total length of the spring 19 when the spring 19 is compressed and adjacent coils are in close contact with each other.

[0059] The valve-side support portion 87 is a cylindrical member. The outer surface of the valve-side support portion 87 is a cylindrical surface. The outer diameter of the valve-side support portion 87 is smaller than the inner diameter of the valve inner diameter portion 69. The valve-side support portion 87 is loosely fitted into the valve inner diameter portion 69.

[0060] The flange portion 88 is an annular member. The outer surface of the flange portion 88 is a cylindrical surface. The outer diameter of the flange portion 88 is smaller than the inner diameter of the fifth inner diameter portion 51e. The flange portion 88 is loosely fitted into the fifth inner diameter portion 51e.

[0061] The pipe fitting 10 is configured such that when the valve 18 is moved in the detachment direction B by the spring 19, the flow path 52 formed by the inner diameter portion 51 of the body is closed, and when a tube is inserted into the inner diameter portion 51 of the body, the valve 18 is moved in the insertion direction A, and the flow path 52 is opened.

[0062] <Method for manufacturing pipe fittings> First, prepare the body 11. Next, insert the spring 19 into the fifth inner diameter portion 51e of the body's inner diameter portion 51. The spring 19 will come into contact with the contact portion 91 formed between the fifth inner diameter portion 51e and the sixth inner diameter portion 51f.

[0063] Next, the spring guide 20 is inserted into the fifth inner diameter portion 51e. The spring-side support portion 86 of the spring guide 20 is loosely fitted into the spring inner diameter portion 81.

[0064] Next, the valve 18 is inserted into the fifth inner diameter portion 51e. The valve-side support portion 87 of the spring guide 20 is loosely fitted onto the valve inner diameter portion 69 of the valve 18.

[0065] Next, the valve stop 17 is inserted into the fourth inner diameter portion 51d. The base portion 66 of the valve 18 is pressed in the insertion direction A by the valve stop 17. The spring 19 contracts. As a result, the spring 19 biases the valve 18 in the release direction B. The total length of the spring 19 when the valve stop 17 is installed and compressed is called the installation height. The spring 19 can be compressed until the spring-side support portion 86 of the spring guide 20 contacts the contact portion 91. The height of the spring 19 when the spring-side support portion 86 and the contact portion 91 are in contact is less than the installation height.

[0066] Next, the tube seal 16 is inserted into the third inner diameter portion 51c. The sealing portion 67 of the valve 18 comes into contact with the tube seal 16. The valve 18 is then closed.

[0067] Next, the spacer 15 is inserted into the second inner diameter portion 51b. The tube seal 16 is sandwiched and fixed between the valve stop 17 and the spacer 15.

[0068] Next, the collar 12, incorporating the lock ring 13 and the back ring 14, is inserted into the first inner diameter portion 51a.

[0069] Next, the crimping portion 36 at the tip of the straight portion 32 is crimped. The collar 12 is fixed to the first inner diameter portion 51a. After this, the release sleeve 21 can be inserted from the tip opening 42 in the insertion direction A to manufacture the pipe fitting 10.

[0070] <Function and Effects of Pipe Fittings> The connection portion 33 of the pipe fitting 10 is connected to the vehicle's cooling circuit. A tube is inserted into the tip opening 42 of the body 11 of the pipe fitting 10. The tube is moved in insertion direction A and inserted into the lock ring 13. The lock ring 13 allows the tube to move in insertion direction A and restricts the tube to move in disengagement direction B.

[0071] The tube is moved further in insertion direction A and comes into contact with a plurality of projections 76 provided at the tip of the valve 18. As the tube is moved further in insertion direction A, the valve 18 is pressed against the tube and the spring 19 contracts. As the spring 19 contracts, the valve 18 and the spring guide 20 move in insertion direction A. The tube seal 16 separates from the seal portion 67 of the valve 18. That is, the valve 18 opens. The tube seal 16 and the outer surface of the tube come into contact, closing the space between the body 11 and the tube, and ensuring fluid tightness. The flow path 52 formed by the inner diameter portion 51 of the body and the flow path inside the tube are connected.

[0072] As shown in Figure 3, when the tube 96 is moved further in the insertion direction A, the spring-side support portion 86 and the contact portion 91 of the spring guide 20 come into contact. The movement of the spring guide 20 in the insertion direction A is restricted, and the movement of the valve 18 and the tube 96 in the insertion direction A is restricted. In this way, when the spring-side support portion 86 and the contact portion 91 come into contact, the coils of the spring 19 are not in close contact with each other. That is, the height of the spring 19 when the valve-side support portion 87 and the contact portion 91 come into contact is greater than the height of the spring 19 in close contact.

[0073] The pipe fitting 10 is attached to the cooling piping. Normally, the pipe fitting 10 is in a state where the tube 96 is not inserted, but when the internal cooling water is replaced, the tube 96 is inserted to discharge the cooling water and air. After the cooling water is discharged, new cooling water is supplied by creating a negative pressure in the cooling piping ranging from 0 Pa to -90 kPa. The spring 19 continues to bias the valve 18 in the release direction B via the spring guide 20 against the negative pressure inside the pipe fitting 10. As a result, the pipe fitting 10 can maintain a state in which the valve 18 does not open due to the negative pressure.

[0074] The pipe joint 10 according to this embodiment includes a spring guide 20 that supports the spring 19. The spring guide 20 has a spring-side support portion 86 that is inserted into the inner diameter portion 81 of the spring, a valve-side support portion 87 that is inserted into the inner diameter portion 69 of the valve, and a flange portion 88 that is sandwiched between the spring 19 and the valve 18. The spring 19 is positioned radially inward of the inner diameter portion 51 of the body and radially outward of the spring-side support portion 86, thereby increasing the spring constant compared to conventional designs while suppressing an increase in the spring wire diameter. Therefore, the pipe joint 10 can prevent the valve 18 from opening due to negative pressure when the tube 96 is not inserted, while suppressing an increase in size.

[0075] The pipe joint 10 optimizes the spring constant of the spring 19 by using a spring guide 20. In the pipe joint 10, components other than the spring 19 and spring guide 20, such as the body 11 and valve 18, can be made using conventional components. Therefore, the pipe joint 10 can reduce manufacturing costs by using conventional components.

[0076] The spring guide 20 is configured such that the height of the spring 19 when the spring-side support portion 86 and the contact portion 91 come into contact is greater than the height of the fully compressed spring 19, thereby limiting the compression of the spring 19 and suppressing the sagging of the spring 19.

[0077] The spring guide 20 has a flange portion 88 that is loosely fitted into the inner diameter portion 51 of the body, a spring-side support portion 86 that is loosely fitted into the inner diameter portion 81 of the spring, and a valve-side support portion 87 that is loosely fitted into the inner diameter portion 69 of the valve. This further suppresses the increase in size and prevents the valve 18 from opening due to negative pressure when the tube 96 is not inserted.

[0078] For example, in a pipe fitting 10 using a spring 19 with a spring constant of 1.29 N / mm and a free height of 23.2 mm, simulations confirmed that when a negative pressure of -90 kPa is supplied, the opening of the valve 18 is prevented and the deformation of the spring 19 is suppressed.

[0079] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and can be modified as appropriate within the scope of the spirit of the present invention. [Explanation of symbols]

[0080] 10 Pipe fittings 11 Body 18 valves 19 Spring 20 Spring Guide 51 Inner diameter of the body 52 channels 69 Valve inner diameter 81 Spring inner diameter 86 Spring-side support part 87 Valve-side support section 88 Flange section 91 Contact part 96 Tubes A Insertion direction B Departure direction

Claims

1. A cylindrical body having an inner diameter portion into which a tube is inserted, A bottomed cylindrical valve is provided in the inner diameter portion of the body so as to be movable in the direction of insertion of the tube and in the direction of removal opposite to the insertion direction, A cylindrical spring is provided in the inner diameter portion of the body to bias the valve in the detachment direction. A pipe fitting comprising the following: the valve is moved in the detachment direction by the spring, thereby closing the flow path formed by the inner diameter portion of the body; and the flow path is opened when the valve is moved in the insertion direction by inserting the tube into the inner diameter portion of the body, The spring guide supports the aforementioned spring, The spring guide is a pipe joint having a spring-side support portion inserted into the inner diameter of the spring, a valve-side support portion inserted into the inner diameter of the valve, and a flange portion provided between the spring-side support portion and the valve-side support portion, protruding radially outward and sandwiched between the spring and the valve.

2. The inner diameter portion of the body has a contact portion that comes into contact with the spring-side support portion when the valve is moved in the insertion direction by the insertion of the tube. The pipe joint according to claim 1, wherein the height of the spring when the spring-side support portion and the contact portion are in contact is greater than the height of the spring when it is fully compressed.

3. The flange portion is loosely fitted into the inner diameter portion of the body. The spring-side support portion is loosely fitted into the inner diameter portion of the spring. The pipe fitting according to claim 1, wherein the valve-side support portion is loosely fitted into the inner diameter portion of the valve.

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