Pipe fittings

Abstract

To provide pipe fittings with excellent sealing and cleanability. [Solution] The pipe fitting 10 comprises a body 11 into which a tube is inserted, a collet case 12 housed inside the body 11, and a collet 13 provided inside the collet case 12 so as to be movable in the tube insertion direction A and the tube removal direction B. When the tube is inserted into the body 11, the collet 13 moves in the insertion direction A, and when the tube is removed from the body 11, the collet 13 moves in the removal direction B. The collet 13 has a cylindrical locking claw portion that can be expanded and contracted. The locking claw portion contracts in diameter and locks onto the tube when the tube is inserted into the body 11. In the state before the tube is inserted into the body 11, the inner diameter of the locking claw portion of the pipe fitting 10 is larger than the outer diameter of the tube.

Description

Technical Field

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

Background Art

[0002] A pipe joint that connects a tube through which a fluid flows and equipment is known (see Patent Document 1). The pipe joint of Patent Document 1 includes a joint body into which the tube is inserted, and a lock member housed inside the joint body for locking the tube. The lock member has claw portions directed radially inward of the joint body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the pipe joint of Patent Document 1, when the tube is inserted into the joint body, the claw portions of the lock member come into contact with the outer peripheral surface of the tube, so the outer peripheral surface of the tube is scraped, and sealing performance and cleanliness are impaired. If the sealing performance and cleanliness are impaired, there is a risk that fluid will leak from the scratched portion of the outer peripheral surface of the tube to cause a slow leak, or particles resulting from damage to the tube will mix into the fluid as foreign matter.

[0005] An object of the present invention is to provide a pipe joint that is excellent in sealing performance and cleanliness.

Means for Solving the Problems

[0006] The pipe fitting according to the present invention comprises a body into which a tube is inserted, a collet case housed inside the body, and a collet provided inside the collet case so as to be movable in the direction of insertion of the tube and in a direction of removal opposite to the insertion direction, wherein the collet moves in the insertion direction when the tube is inserted into the body, and the collet moves in the removal direction when the tube is removed from the body, wherein the collet has a cylindrical locking claw portion that can be expanded and contracted in diameter, the locking claw portion contracts in diameter and locks onto the tube when the tube is inserted into the body, and the inner diameter of the locking claw portion is larger than the outer diameter of the tube before the tube is inserted into the body. [Effects of the Invention]

[0007] According to the present invention, since the inner diameter of the collet is larger than the outer diameter of the tube before the inserted tube is fixed, abrasion of the outer surface of the tube can be suppressed, thereby providing a pipe fitting with excellent sealing and cleanliness. [Brief explanation of the drawing]

[0008] [Figure 1] This is a partially broken perspective view of a pipe joint according to an embodiment of the present invention. [Figure 2] This is an exploded perspective view of a pipe joint according to an embodiment of the present invention. [Figure 3A] This is a front view of the body. [Figure 3B] This is a side view of the body, seen from the front. [Figure 3C] Figure 3B is a cross-sectional view along the IIIC-IIIC line. [Figure 4A] This is a front view of the collet case. [Figure 4B] This is a side view of the collet case, seen from the base end. [Figure 4C] Figure 4B is a cross-sectional view along the IVC-IVC line. [Figure 5A] This is a front view of Colette. [Figure 5B] It is a side view of the collet viewed from the proximal end side. [Figure 6A] It is a front view of the front ring. [Figure 6B] It is a side view of the front ring viewed from the proximal end side. [Figure 7A] It is a front view of the seal ring. [Figure 7B] It is a side view of the seal ring viewed from the proximal end side. [Figure 8A] It is a front view of the cap. [Figure 8B] It is a side view of the cap viewed from the proximal end side. [Figure 9] It is an explanatory view for explaining the operation of the pipe joint. [Figure 10] It is an explanatory view for explaining the operation of the pipe joint. [Figure 11] It is an explanatory view for explaining the operation of the pipe joint. [Figure 12] It is an explanatory view for explaining the operation of the pipe joint. [Figure 13] It is an explanatory view for explaining the operation of the pipe joint. [Mode for Carrying Out the Invention]

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

[0010] (1) Configuration of Pipe Joint Figure 1 is a partially cutaway perspective view of a pipe joint 10 according to an embodiment of the present invention. Figure 2 is an exploded perspective view of the pipe joint 10 according to the embodiment of the present invention. The pipe joint 10 is used for connecting a tube (not shown) for circulating various fluids such as liquid and gas, and an apparatus (not shown).

[0011] In Figures 1 and 2, the pipe fitting 10 comprises a body 11, a collet case 12, a collet 13, a front ring 14, a seal ring 15, and a cap 16. In Figure 1, parts of the body 11, collet case 12, front ring 14, seal ring 15, and cap 16 are shown in a cutaway view, and the appearance of the collet 13 is also shown. The body 11, collet case 12, collet 13, and cap 16 are cylindrical members, while the front ring 14 and seal ring 15 are annular members. The pipe fitting 10 has a configuration in which the collet case 12, collet 13, front ring 14, seal ring 15, and cap 16 are coaxially housed inside the body 11.

[0012] In the pipe fitting 10, a tube is inserted into the 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 A, is called the removal direction B. The side with the insertion direction A is called the base end, and the side with the removal direction B is called the tip end. The direction along the central axis CL of the pipe fitting 10 is called the "axial direction," the radial direction centered on the central axis CL of the pipe fitting 10 is called the "radial direction," and the direction around the central axis CL of the pipe fitting 10 is called the "circumferential direction."

[0013] Figure 3A is a front view of the body 11. Figure 3B is a side view of the body 11 seen from the front end. Figure 3C is a cross-sectional view along the line IIIC-IIIC in Figure 3B. The body 11 is made of a resin such as PPS (polyphenylene sulfide). These resins such as PPS may be made of resin alone, or they may be compounded with glass fibers or other materials to enhance their mechanical strength as needed. The body 11 is not limited to being made of resin, but may also be made of metal or an alloy.

[0014] The body 11 has a mounting portion 21 for connecting to equipment, a tube insertion portion 22 into which a tube is inserted, and a tool engagement portion 23 into which a tool is engaged. In this example, the mounting portion 21, the tube insertion portion 22, and the tool engagement portion 23 are formed integrally, but they may be formed separately.

[0015] The mounting portion 21 is provided on the base end side of the body 11. The mounting portion 21 has a male thread that screws into the female thread formed on the equipment. The pipe fitting 10 is attached to the equipment by screwing the male thread of the mounting portion 21 into the female thread of the equipment.

[0016] The tube insertion section 22 is located at the front end of the body 11. The tube insertion section 22 has an opening 24 into which a tube is inserted. The tube insertion section 22 holds the collet case 12, collet 13, front ring 14, seal ring 15, and cap 16 inside.

[0017] The tool engagement portion 23 is provided between the mounting portion 21 and the tube insertion portion 22. The tool engagement portion 23 engages with tools such as spanners and wrenches. In this embodiment, the external shape of the tool engagement portion 23 is hexagonal. The external shape of the tool engagement portion 23 is not limited to hexagonal, but may be various shapes that allow tools to engage, such as polygons like squares and octagons, or rectangles with rounded corners.

[0018] The body 11 has a recess 25 that fits with a protrusion 73 of the cap 16, which will be described later. The recess 25 is provided in the tube insertion portion 22. The recess 25 is formed in a slit shape. The recess 25 extends along the circumferential direction of the body 11. The recess 25 is a through groove that penetrates the outer and inner circumferential surfaces of the tube insertion portion 22. In this embodiment, two recesses 25 are provided at symmetrical positions with respect to the central axis of the body 11. In Figure 3A, one of the two recesses 25 is shown, and the other recess 25 is hidden at the back of the page. The number of recesses 25 is not limited to two, but can be one or more. The recess 25 is not limited to extending along the circumferential direction of the body 11, but may also extend along the axial direction of the body 11. The recess 25 is not limited to being a slit shape, but may also be a spot shape, etc. The recess 25 is not limited to being a through groove, but may also be a non-penetrating groove provided on the inner circumferential surface of the tube insertion portion 22.

[0019] The body 11 has a rotation restricting portion 26 that restricts the rotation of the collet case 12. The rotation restricting portion 26 fits into a notch 35 of the collet case 12, which will be described later. The rotation restricting portion 26 protrudes from the inner circumferential surface of the body 11 toward the radially inward direction of the body 11. The rotation restricting portion 26 extends along the axial direction of the body 11. In this embodiment, two rotation restricting portions 26 are provided at symmetrical positions with respect to the central axis of the body 11. The number of rotation restricting portions 26 is not limited to two, but may be one or more. The rotation restricting portion 26 is not limited to extending along the axial direction of the body 11, but may also extend along the circumferential direction of the body 11.

[0020] An annular end face 27 is provided on the base end side inside the body 11, perpendicular to the axial direction of the body 11. The end face 27 abuts against the base end of the collet 13, which will be described later.

[0021] Figure 4A is a front view of the collet case 12. Figure 4B is a side view of the collet case 12 viewed from the base end. Figure 4C is a cross-sectional view along the IVC-IVC line in Figure 4B. The collet case 12 is made of a resin such as PPS. This resin such as PPS may be a pure resin, or it may be reinforced with glass fibers or other materials as needed to enhance its mechanical strength. The collet case 12 is not limited to being made of resin, but may also be made of metal or an alloy.

[0022] The collet case 12 is housed inside the body 11. The collet case 12 has a cylindrical case body 31, a guide portion 32 that guides the movement of the projection 43 of the collet 13 (described later), and a locking portion 33 into which the projection 43 of the collet 13 is locked. The guide portion 32 and the locking portion 33 are provided on the base end side of the case body 31.

[0023] The guide portion 32 is formed in a spiral shape. The tip and base of the guide portion 32 in the axial direction of the collet case 12 are positioned at different locations in the axial direction of the collet case 12, and also at different locations in the circumferential direction of the collet case 12. The tip of the guide portion 32 is positioned at a predetermined position in the axial direction of the collet case 12 (in Figure 4A, at an intermediate position in the axial direction of the collet case 12). The base of the guide portion 32 is positioned at the base of the collet case 12. The guide portion 32 extends along a direction inclined with respect to the axial direction of the collet case 12. The guide portion 32 is formed in a slit shape. The guide portion 32 is a through groove that penetrates the outer and inner circumferential surfaces of the case body 31. In this embodiment, two guide portions 32 are provided at symmetrical positions with respect to the central axis of the collet case 12. The number of guide portions 32 is not limited to two, but may be one or more. The guide portion 32 is not limited to extending in a direction inclined with respect to the axial direction of the collet case 12, but may have a shape having a first straight portion extending along the axial direction of the collet case 12 and a second straight portion extending along the circumferential direction of the collet case 12. The guide portion 32 is not limited to being a through groove, but may be a non-through groove provided on the inner circumferential surface of the case body 31.

[0024] The locking portion 33 is connected to the guide portion 32. The locking portion 33 is formed in a straight line. The locking portion 33 extends along the circumferential direction of the collet case 12. One end of the locking portion 33 in the circumferential direction of the collet case 12 is connected to the base end of the guide portion 32. The other end of the locking portion 33 in the circumferential direction of the collet case 12 is positioned in the axial direction of the collet case 12, corresponding to the tip of the guide portion 32. The locking portion 33 is formed in a slit shape. The locking portion 33 is a through groove that penetrates the outer and inner circumferential surfaces of the case body 31. In this embodiment, two locking portions 33 are provided at symmetrical positions with respect to the central axis of the collet case 12. The number of locking portions 33 is not limited to two, but may be one or more. The locking portion 33 is not limited to extending along the circumferential direction of the collet case 12, but may also extend in a direction inclined with respect to the axial direction of the collet case 12. In this case, one end and the other end of the locking portion 33 are positioned at different axial positions on the collet case 12 and at different circumferential positions on the collet case 12. For example, one end of the locking portion 33 is positioned at the base end of the collet case 12, and the other end of the locking portion 33 is positioned on the other end side of the tip of the guide portion 32 in the axial direction of the collet case 12. The locking portion 33 is not limited to being a through groove, but may also be a non-through groove provided on the inner circumferential surface of the case body 31.

[0025] The collet case 12 has a notch 35 that engages with the rotation restricting portion 26 of the body 11. The notch 35 is provided at the base end of the collet case 12. The notch 35 is formed in a slit shape. The notch 35 extends along the axial direction of the collet case 12. The notch 35 is a through groove that penetrates the outer and inner circumferential surfaces of the case body 31. In this embodiment, two notches 35 are provided at symmetrical positions with respect to the central axis of the collet case 12. The rotation of the collet case 12 relative to the body 11 is restricted by the engagement of the notches 35 of the collet case 12 with the rotation restricting portion 26 of the body 11. The number of notches 35 is not limited to two, but may be one or more. The notches 35 are not limited to extending along the axial direction of the collet case 12, but may also extend along the circumferential direction of the collet case 12. The notch 35 is not limited to being a through groove, but may also be a non-through groove provided on the outer circumferential surface of the case body 31.

[0026] As shown in Figure 4C, the inner circumferential surface of the collet case 12 has a large inner diameter portion 37 provided on the tip side of the collet case 12, a small inner diameter portion 38 provided on the base side of the collet case 12, and a stepped portion 39 provided between the large inner diameter portion 37 and the small inner diameter portion 38. The inner diameter of the small inner diameter portion 38 is smaller than the inner diameter of the large inner diameter portion 37. The stepped portion 39 has an annular plane perpendicular to the axial direction of the collet case 12.

[0027] Figure 5A is a front view of the collet 13. Figure 5B is a side view of the collet 13 viewed from the base end. The collet 13 is made of a resin such as PPS. This resin such as PPS may be a pure resin, or it may be reinforced with glass fibers or other materials as needed to increase its mechanical strength. The collet 13 is not limited to being made of resin, but may also be made of metal or an alloy.

[0028] The collet 13 is located inside the collet case 12 and is movable in both the tube insertion direction A and the tube removal direction B. The pipe fitting 10 is configured such that the collet 13 moves in the insertion direction A when the tube is inserted into the body 11, and moves in the removal direction B when the tube is removed from the body 11.

[0029] The collet 13 has an annular retaining portion 41, a cylindrical locking claw portion 42 that can be expanded and contracted, and a projection 43 that engages with the guide portion 32 of the collet case 12. The retaining portion 41 holds the locking claw portion 42. In this example, the retaining portion 41, the locking claw portion 42, and the projection 43 are formed integrally, but they may be formed separately.

[0030] The locking claw portion 42 is configured to contract in diameter and lock onto the tube when the tube is inserted into the body 11. The locking claw portion 42 is provided at the tip of the holding portion 41. The locking claw portion 42 has a plurality of claw portions 45 arranged radially around the central axis of the collet 13, and a plurality of connecting portions 46 that connect the plurality of claw portions 45 to the holding portion 41. In this embodiment, there are 12 claw portions 45 and 12 connecting portions 46 for each holding portion 41. In Figure 5B, 10 of the 12 connecting portions 46 are shown, and 2 connecting portions 46 are hidden behind the projection portion 43 (towards the back of the paper). The number of claw portions 45 and connecting portions 46 is not limited to 12, but can be 2 or more.

[0031] The claw portion 45 is provided at the tip of the connecting portion 46. The claw portion 45 protrudes radially inward from the inner surface of the connecting portion 46 towards the collet 13. The inner diameter of the locking claw portion 42 is the diameter of the imaginary circle connecting the multiple claw portions 45.

[0032] The connecting portion 46 is provided at the tip of the holding portion 41. The connecting portion 46 extends from the tip of the holding portion 41 toward the tip of the collet 13. The outer surface of the connecting portion 46 is connected to the outer circumferential surface of the holding portion 41 and is inclined toward the radially outward direction of the collet 13 as it approaches the tip of the collet 13. The connecting portion 46 is elastically deformable so as to bend radially inward or outward of the collet 13, starting from the connection point between the connecting portion 46 and the holding portion 41.

[0033] The projection 43 is provided on the outer circumferential surface of the holding portion 41. The projection 43 protrudes radially outward from the outer circumferential surface of the holding portion 41. The tip and other end of the projection 43 in the axial direction of the collet 13 are positioned at different locations in the axial direction of the collet 13 and at different locations in the circumferential direction of the collet 13. The tip of the projection 43 is positioned at the tip of the holding portion 41. The base end of the projection 43 is positioned at the base end of the holding portion 41. The projection 43 extends along a direction inclined with respect to the axial direction of the collet 13. The cross-sectional shape of the projection 43 is a parallelogram. In this embodiment, two projections 43 are provided at symmetrical positions with respect to the central axis of the collet 13. The number of projections 43 is not limited to two, but may be one or more. The cross-sectional shape of the projection 43 is not limited to a parallelogram, but may be circular, elliptical, rectangular, etc.

[0034] The locking claw portion 42 has a convex curved portion 47 that contacts the tapered portion 52 of the front ring 14, which will be described later. The curved portion 47 is provided on the tip side of the claw portion 45. The tapered portion 52 of the front ring 14, which will be described later, is received in the recess provided between the curved portion 47 and the claw portion 45.

[0035] The locking claw portion 42 is displaceable between a state before the tube is inserted into the body 11 (hereinafter referred to as the initial state) and a state in which the tube is locked to the body 11 and fixed in place (hereinafter referred to as the fixed state). In the initial state, the inner diameter of the locking claw portion 42 (the diameter of the imaginary circle connecting the multiple claw portions 45) is larger than the outer diameter of the tube. In the initial state, the locking claw portion 42 does not come into contact with the outer surface of the tube, thus minimizing damage to the tube. In the initial state, the leading edge of the outer surface of the locking claw portion 42 (the outer surface of the connecting portion 46) is in contact with the large inner diameter portion 37 on the inner surface of the collet case 12. As the collet 13 moves from its initial position toward the base end, the outer surface of the locking claw portion 42 comes into contact with the stepped portion 39 on the inner circumferential surface of the collet case 12. The outer surface of the locking claw portion 42 is pressed against the stepped portion 39 of the collet case 12, causing the locking claw portion 42 to shrink in diameter. As the locking claw portion 42 shrinks in diameter, it comes into contact with the outer circumferential surface of the tube. In the fixed state, the inner diameter of the locking claw portion 42 is smaller than the outer diameter of the tube. In the fixed state, the locking claw portion 42 bites into the outer circumferential surface of the tube, preventing the tube from coming loose.

[0036] Figure 6A is a front view of the front ring 14. Figure 6B is a side view of the front ring 14 as seen from the base end. The front ring 14 is made of a resin such as PPS. This resin such as PPS may be a pure resin, or it may be reinforced with glass fibers or other materials as needed to enhance its mechanical strength. The front ring 14 is not limited to being made of resin, but may also be made of metal or an alloy.

[0037] The front ring 14 is located further forward than the collet 13. The front ring 14 is intended to guide the tube accurately into the collet 13 and to hold down the seal ring 15, which will be described later.

[0038] The front ring 14 has an annular ring body 51 and a tapered portion 52 provided at the base end of the ring body 51. The base end surface of the ring body 51 abuts against the front end surface of the collet case 12.

[0039] The tapered portion 52 contacts the curved portion 47 provided at the tip of the locking claw portion 42 of the collet 13. The tapered portion 52 is inclined radially outward of the front ring 14 as it approaches the front end of the front ring 14. In this example, the tapered portion 52 is provided around the opening of the front ring 14, but it is not limited to this, and can be provided in a position where it can contact the curved portion 47 of the collet 13.

[0040] As the tube inserted into the body 11 moves in the release direction B, the collet 13 moves along with the movement of the tube, and the curved portion 47 of the locking claw portion 42 of the collet 13 comes into contact with the tapered portion 52 of the front ring 14. As the tube moves further in the release direction B, the curved portion 47 of the locking claw portion 42 of the collet 13 is pressed radially outward by the tapered portion 52 of the front ring 14. This causes the locking claw portion 42 of the collet 13 to expand in diameter. As a result of the expansion of the locking claw portion 42 of the collet 13, the locking between the outer surface of the tube and the locking claw portion 42 is released. With the locking between the locking claw portion 42 of the collet 13 and the outer surface of the tube released, the tube can be removed from the body 11.

[0041] Figure 7A is a front view of the seal ring 15. Figure 7B is a side view of the seal ring 15 viewed from the base end. The seal ring 15 is made of rubber such as EPDM (ethylene propylene diene rubber).

[0042] The seal ring 15 is an elastic member that seals to prevent fluid leakage from inside the pipe fitting 10. The seal ring 15 is located further forward than the front ring 14. An annular thickened portion 62 is provided in the axial center of the seal ring 15. The outer surface of the thickened portion 62 is in close contact with the inner surface of the body 11, and the inner surface is in close contact with the outer surface of the tube. The seal ring 15 is made of, for example, an O-ring.

[0043] Figure 8A is a front view of the cap 16. Figure 8B is a side view of the cap 16 as seen from the base end. The cap 16 is made of a resin such as PPS. This resin such as PPS may be a pure resin, or it may be reinforced with glass fibers or other materials to enhance its mechanical strength as needed. The cap 16 is not limited to being made of resin, but may also be made of metal or an alloy.

[0044] The cap 16 guides the tube into the body 11 and holds in the collet case 12, collet 13, front ring 14, and seal ring 15 housed inside the body 11.

[0045] The cap 16 is located further forward than the seal ring 15. The cap 16 has an annular opening 71, a cylindrical elastic tubular portion 72 that can expand and contract in diameter, provided at the base end of the opening 71, and a protrusion 73 provided on the outer circumferential surface of the elastic tubular portion 72.

[0046] The cap 16 receives the tube through the opening 71. The opening 71 is connected to the elastic cylindrical part 72 via an annular connector 74. The outer diameter of the connector 74 is smaller than the outer diameter of the opening 71.

[0047] The outer diameter of the elastic cylindrical portion 72 is smaller than the outer diameter of the opening 71 and larger than the outer diameter of the connecting portion 74. The elastic cylindrical portion 72 is composed of a plurality of block bodies 72A arranged at intervals from each other in the circumferential direction of the cap 16. The outer diameter of the elastic cylindrical portion 72 is the diameter of a virtual circle that includes the outer circumferential surfaces of the plurality of block bodies 72A. The elastic cylindrical portion 72 is elastically deformable so that the plurality of block bodies 72A can bend inward or outward in the radial direction of the cap 16, starting from the connection point between the elastic cylindrical portion 72 and the connecting portion 74. In this example, the elastic cylindrical portion 72 is composed of four block bodies 72A. The four block bodies 72A are arranged at equal intervals in the circumferential direction of the cap 16. The number of block bodies 72A is not limited to four; it can be two or more.

[0048] The protrusions 73 project radially outward from the outer circumferential surface of the elastic cylindrical portion 72. The protrusions 73 extend in the circumferential direction of the cap 16. In this embodiment, the protrusions 73 are provided on the outer circumferential surfaces of two of the four block bodies 72A, which are positioned symmetrically with respect to the central axis of the cap 16. That is, two protrusions 73 are provided symmetrically with respect to the central axis of the cap 16. The diameter of the virtual circle containing the outer circumferential surfaces of the two protrusions 73 is larger than the outer diameter of the opening 71. The rotation of the cap 16 relative to the body 11 is restricted by the fitting of the protrusions 73 of the cap 16 with the recesses 25 of the body 11. The number of protrusions 73 is not limited to two, but may be one or more.

[0049] (2) Method of manufacturing pipe fittings First, the collet 13 is inserted into the collet case 12 from the base end. The projection 43 of the collet 13 is positioned on the guide portion 32 or the locking portion 33 of the collet case 12. Since the guide portion 32 and the locking portion 33 of the collet case 12 are connected to each other, the collet 13 is housed inside the collet case 12 such that the projection 43 can move along the guide portion 32 and the locking portion 33.

[0050] Next, the collet case 12, with the collet 13 housed inside, is inserted into the body 11 through the opening 24 of the tube insertion portion 22 of the body 11. The collet case 12 is rotated while being pushed toward the base end of the body 11, so that the rotation restricting portion 26 provided on the inner circumferential surface of the body 11 engages with the notch portion 35 of the collet case 12. This restricts the rotation of the collet case 12 relative to the body 11.

[0051] Next, the front ring 14 is inserted into the body 11. The base end surface of the ring body 51 of the front ring 14 is brought into contact with the front end surface of the collet case 12. At this time, the tip edge of the outer surface of the locking claw portion 42 (outer surface of the connecting portion 46) comes into contact with the large inner diameter portion 37 of the inner circumferential surface of the collet case 12. The curved portion 47 provided at the tip of the locking claw portion 42 of the collet 13 comes into contact with the tapered portion 52 of the front ring 14.

[0052] Next, the seal ring 15 is inserted into the body 11. The annular thickened portion 62 provided on the outer surface of the seal ring 15 comes into close contact with the inner surface of the body 11.

[0053] Next, the cap 16 is inserted into the body 11. The cap 16 is rotated while being pushed towards the base end of the body 11, so that the recess 25 of the body 11 and the protrusion 73 of the cap 16 are engaged. This restricts the rotation of the cap 16 relative to the body 11. The pipe fitting 10 is manufactured in this manner. In the pipe fitting 10, the seal ring 15 is positioned towards the tip of the locking claw portion 42 of the collet 13. Therefore, when a tube is inserted into the pipe fitting 10, the tip of the tube passes the seal ring 15 before reaching the collet 13.

[0054] (3) Operation and effect of pipe fittings The operation of the pipe fitting 10 will be explained using Figures 9 to 13. Figures 9 to 12 are partial cross-sectional views of the pipe fitting 10. In Figure 9, parts of the body 11, collet case 12, collet 13, front ring 14, seal ring 15, and cap 16 are shown in cross-section. In Figures 10 to 12, parts of the body 11, collet case 12, front ring 14, seal ring 15, and cap 16 are shown in cross-section, and the appearance of the collet 13 is also shown. Figure 13 shows how, when the tube 80 is pulled in the detachment direction B, the curved portion 47 provided on the locking claw portion 42 of the collet 13 comes into contact with the tapered portion 52 of the front ring 14, causing the locking claw portion 42 of the collet 13 to expand in diameter.

[0055] First, the process of inserting a tube into the pipe fitting 10 will be explained, and then the process of removing a tube from the pipe fitting 10 will be explained.

[0056] When inserting a tube into the pipe fitting 10, the worker connects the mounting portion 21 of the body 11 of the pipe fitting 10 to equipment (not shown). By engaging a tool such as a spanner or wrench with the tool engagement portion 23 of the body 11 and rotating the tool engagement portion 23 with the tool, the equipment and the pipe fitting 10 can be connected.

[0057] As shown in Figure 9, the operator inserts the tube 80 into the opening 24 of the tube insertion section 22 of the body 11. The tube 80 is inserted into the collet 13 located inside the collet case 12 via the cap 16, seal ring 15, and front ring 14. The tip surface of the tube 80 comes into contact with the tip side surface (also referred to as the bottom surface) of the holding section 41 of the collet 13. In this state, the inner diameter of the locking claws 42 of the collet 13 (the diameter of the virtual circle connecting the tips of the multiple claws 45) is larger than the outer diameter of the tube, similar to the state when the tube is not inserted into the body 11 (initial state). Therefore, the locking claws 42 of the collet 13 do not lock onto the tube.

[0058] As shown in Figure 10, when the tube 80 is further inserted in insertion direction A with the tip surface of the tube 80 in contact with the tip side surface (bottom surface) of the holding portion 41 of the collet 13, the projection 43 of the collet 13 is guided by the guide portion 32 of the collet case 12, and the collet 13 moves toward the base end while rotating. The rotation of the collet 13 when inserting the tube 80 is defined as forward rotation. At this time, the stepped portion 39 provided on the inner circumferential surface of the collet case 12 comes into contact with the outer surface of the locking claw portion 42 of the collet 13 (outer surface of the connecting portion 46), and as the collet 13 moves toward the base end, the connecting portion 46 elastically deforms so as to bend inward in the radial direction of the collet 13. Due to the elastic deformation of the connecting portion 46, the locking claw portion 42 shrinks in diameter and comes into contact with the outer circumferential surface of the tube 80. The tube 80 rotates in the forward direction in accordance with the forward rotation of the collet 13.

[0059] As shown in Figure 11, when the base end of the collet 13 comes into contact with the end face 27 provided on the base side inside the body 11, the insertion of the tube 80 is stopped. The projection 43 of the collet 13 is guided from the guide portion 32 of the collet case 12 to the locking portion 33.

[0060] As shown in Figure 12, when the insertion of the tube 80 is stopped, the worker rotates the tube 80 in the reverse direction. As the tube 80 rotates in the reverse direction, the collet 13 rotates in the reverse direction, and the projection 43 of the collet 13 engages with the locking portion 33 of the collet case 12 (fixed state). This fixes the tube 80 to the pipe fitting 10 and prevents the tube 80 from coming out.

[0061] When removing the tube from the pipe fitting 10, the worker performs the operation described above with reference to Figures 9 to 12 in reverse. First, with the projection 43 of the collet 13 locked to the locking portion 33 of the collet case 12 (see Figure 12), the worker rotates the tube 80 in the forward direction. The projection 43 of the collet 13 is guided from the locking portion 33 of the collet case 12 to the guide portion 32 (see Figure 11).

[0062] Next, the operator pulls the tube 80 in the release direction B. The projection 43 of the collet 13 moves along the guide portion 32 of the collet case 12, and the collet 13 moves toward the tip while rotating in the reverse direction (see Figure 10). As the collet 13 moves toward the tip, the connecting portion 46 of the collet 13 elastically deforms so that it bends radially outward. Due to the elastic deformation of the connecting portion 46, the locking claw portion 42 expands in diameter, and the locking claw portion 42 separates from the outer surface of the tube 80.

[0063] As shown in Figure 13, when the tube 80 is further pulled by the operator in the detachment direction B, the curved portion 47 provided on the locking claw portion 42 of the collet 13 comes into contact with the tapered portion 52 of the front ring 14, and the locking claw portion 42 of the collet 13 expands in diameter. In Figure 13, the direction in which the locking claw portion 42 expands in diameter is indicated by a white arrow. As a result of the expansion of the locking claw portion 42 of the collet 13, the locking between the outer surface of the tube 80 and the locking claw portion 42 is more reliably released (see Figure 9). Even if the locking claw portion 42 was fixed to the outer surface of the tube 80, the contact between the curved portion 47 of the collet 13 and the tapered portion 52 of the front ring 14 will reliably expand the locking claw portion 42 of the collet 13, and the locking claw portion 42 will separate from the outer surface of the tube 80. When the locking claw portion 42 of the collet 13 is released from the outer surface of the tube 80, the tube 80 can be removed from the pipe fitting 10.

[0064] As described above, in the pipe fitting 10, before the tube 80 is inserted, the inner diameter of the locking claw portion 42 of the collet 13 is larger than the outer diameter of the tube 80. Until the tube 80 is fixed to the pipe fitting 10, the locking claw portion 42 of the collet 13 is not locked to the tube 80, so the outer surface of the tube 80 is not worn down. Therefore, the pipe fitting 10 can suppress wear on the outer surface of the tube 80, and thus has excellent sealing and cleanliness.

[0065] The collet 13 has an annular retaining portion 41 that holds the locking claw portion 42, and a projection 43 that protrudes radially outward from the outer circumferential surface of the retaining portion 41. The collet case 12 has a guide portion 32 that guides the projection 43, and a locking portion 33 that is connected to the guide portion 32 and into which the projection 43 is locked. The guide portion 32 has a tip and a base end that are positioned at different axial and circumferential positions of the collet case 12. The locking portion 33 extends from the base end of the guide portion 32 to a position corresponding to the tip of the guide portion 32 in the circumferential direction of the collet case 12. When a tube 80 is inserted into the pipe fitting 10, the projection 43 of the collet 13, which is fitted into the guide portion 32 of the collet case 12, moves along the guide portion 32, and the collet 13 moves toward the base end while rotating in the forward direction. At this time, as the collet 13 rotates in the forward direction, the tube 80 rotates in the forward direction, causing the tube 80 to twist. Subsequently, when the tube 80 rotates in the reverse direction, the projection 43 of the collet 13 engages with the locking portion 33, fixing the tube 80 to the pipe fitting 10. In this way, because the tube 80 rotates in the reverse direction when it is fixed to the pipe fitting 10, the twisting of the tube 80 can be eliminated.

[0066] The collet case 12 has a spirally formed guide portion 32 and a linearly formed locking portion 33. When the operator pushes the tube 80 in, the tube 80 is forced to rotate in the forward direction along the spiral guide portion 32, and when the tube 80 reaches the back of the body 11, a force acts on the tube 80 in the reverse direction due to the restoring force against twisting. Therefore, the tube 80 can be easily fixed to the pipe fitting 10.

[0067] The front ring 14 has a tapered portion 52 that slopes radially outward toward the tip of the front ring 14. The locking claw portion 42 of the collet 13 has a curved portion 47 that contacts the tapered portion 52. When the tube 80 inserted into the body 11 is removed from the body 11, the curved portion 47 contacts the tapered portion 52, expanding the diameter of the locking claw portion 42. The pipe fitting 10 can more reliably release the lock between the outer surface of the tube 80 and the locking claw portion 42 when the tube 80 is pulled out of the body 11.

[0068] In the pipe fitting 10, the seal ring 15 is provided on the tip side of the locking claw portion 42 of the collet 13. Since the portion of the outer surface of the tube 80 other than the portion locked by the locking claw portion 42 can be sealed by the seal ring 15, fluid leakage can be prevented more reliably. After the tip of the tube 80 passes the seal ring 15, the outer surface of the tube 80 and the locking claw portion 42 can be locked together, making the sealing performance even more reliable. The seal ring 15 may also be provided on the base side of the locking claw portion 42 of the collet 13. If the seal ring 15 is provided on the base side of the locking claw portion 42 of the collet 13, it is desirable to consider the number, shape, and arrangement of the seal rings 15.

[0069] A biasing member may be provided between the base end of the collet 13 and the end face 27 located on the base side inside the body 11 to bias the collet 13 in the detachment direction B. The biasing member further strengthens the locking between the projection 43 of the collet 13 and the locking portion 33 of the collet case 12 when the collet is fixed. Also, for example, when a worker connects a tube 80 to the pipe fitting 10, if they release their hand from the tube 80 before the projection 43 of the collet 13 and the locking portion 33 of the collet case 12 lock together, the biasing member will return the collet 13 to the detachment direction B, making it easy to confirm whether the pipe fitting 10 and the tube 80 are securely connected. Conventionally, when connecting a tube to a pipe fitting, it was necessary to mark the tube insertion length in advance, referring to a predetermined length, in order to confirm that the tube was connected to the body, before inserting the tube into the body, which resulted in poor work efficiency. By providing a biasing member between the base end of the collet 13 and the end face 27 located on the base side inside the body 11, it is possible to easily confirm whether the pipe joint 10 and the tube 80 are securely connected without the need for conventional marking, thereby improving work efficiency. [Explanation of Symbols]

[0070] 10 Pipe fittings 11 Body 12 Collet Cases 13 Colette 14 Front Ring 15 Seal rings 16 caps 32 Information Department 33 Locking part 41 Holding part 42 Locking claw portion 43 Protrusion 47 Curved section 52 Tapered section 80 tubes A. Insertion direction B Departure direction

Claims

1. The body into which the tube is inserted, A collet case housed inside the aforementioned body, A collet is provided inside the collet case 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 pipe fitting comprising, wherein the collet moves in the insertion direction when the tube is inserted into the body, and the collet moves in the removal direction when the tube is removed from the body, The collet has a cylindrical locking claw portion that can be expanded and contracted in diameter, The locking claw portion shrinks in diameter when the tube is inserted into the body and locks onto the tube. A pipe fitting in which, before the tube is inserted into the body, the inner diameter of the locking claw portion is larger than the outer diameter of the tube.

2. The collet has an annular retaining portion that holds the locking claw portion, and a projection that protrudes radially outward from the outer circumferential surface of the retaining portion. The collet case has a guide portion that guides the movement of the projection, and a locking portion connected to the guide portion and into which the projection is locked. The guide portion has a tip and a base, which are positioned at different axial positions of the collet case and at different circumferential positions of the collet case. The pipe fitting according to claim 1, wherein the locking portion extends from the base end of the guide portion to a position in the circumferential direction of the collet case corresponding to the tip of the guide portion.

3. The guide portion is formed in a spiral shape, The locking portion is formed in a straight line, as described in claim 2.

4. It is housed inside the body and has a front ring provided on the tip side of the collet, The front ring has a tapered portion that slopes outward in the radial direction of the front ring as it approaches the tip of the front ring. The locking claw portion has a convex curved portion that contacts the tapered portion, The pipe joint according to claim 1 or 2, wherein when the tube inserted into the body is detached from the body, the curved portion comes into contact with the tapered portion, and the locking claw portion expands in diameter.

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