Tube holding jig

Abstract

To provide a tube holding jig capable of improving performance of continuously holding a tube without sliding the tube while suppressing increase in size and increase in manufacturing cost.SOLUTION: A tube holding jig is a jig that holds a tube during an operation of pushing a member such as a sleeve into an open end of the tube, and includes a clamp and a ring. The clamp is configured to clamp an object within a bore of a truncated cone shape. The ring has a coefficient of friction against the tube higher than that of the clamp, and an outer peripheral surface of the ring has a truncated cone shape. The ring is further configured to be coaxially clamped within the bore of the clamp with a larger outer diameter side facing a larger diameter side of the bore while coaxially surrounding the tube with the larger outer diameter side facing an open end of the tube.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] This invention relates to tools used in connecting tubes to fittings, and more particularly to a fixture for holding the tube during the operation of forcing the members of the fitting into the open end of the tube. [Background technology]

[0002] In semiconductor processes, various chemicals or ultrapure water are used for coating resist on wafers, cleaning wafers, etc. Semiconductor manufacturing equipment includes piping facilities such as tubes, pipe fittings, valves, and pumps that handle these chemicals. The characteristics of this piping facilities are that all parts that come into direct contact with the chemicals are made of non-metallic materials such as resin, and that maintenance such as cleaning is relatively frequent. The former is intended to prevent crystal defects in semiconductors and deterioration of electrical characteristics caused by metal contamination, while the latter is intended to prevent wiring processing defects caused by fine particles and film formation abnormalities caused by organic matter. In light of these characteristics, piping facilities are required to have high sealing properties as well as ease of assembly and disassembly.

[0003] Among piping equipment, pipe fittings include those that use a member called a sleeve (also called an inner ring) to connect tubes (see, for example, Patent Document 1). The sleeve includes a bulging portion (hereinafter referred to as the "bulging portion") at one end in the axial direction (hereinafter referred to as the "tip portion"), whose outer diameter is wider than the inner diameter of the tube. When the tip portion of the sleeve is pressed into the open end of the tube, the bulging portion of the sleeve expands the open end from the inside. The elastic force of the tube resists this expansion, causing the open end of the tube to embrace the bulging portion, so that the open end is firmly fixed to the tip portion of the sleeve and the gap between the open end and the tip portion is sealed.

[0004] A dedicated tool is generally used for the operation of pushing the tip of the sleeve into the open end of the tube, i.e., the operation of pressing the sleeve onto the tube (see, for example, Patent Documents 2 and 3). This tool is mainly composed of a jig (hereinafter referred to as the "tube holding jig") that holds the tube during the pressing operation, and a mechanism (hereinafter referred to as the "sleeve pressing mechanism") that presses the tip of the sleeve into the open end of the tube held by the jig. The tube holding jig includes a clamp and a ring. The clamp is generally made of metal and is configured to clamp an object within a cylindrical hole. The ring is generally a non-metallic cylindrical member that is configured to coaxially surround the tube.

[0005] The role of the ring is mainly to prevent the tube from slipping. The non-metallic material constituting the tube, typically fluororesin, has high slipperiness, so if the tube is directly clamped by the clamp, it will easily slip inside the clamp hole during the press-in operation. This may cause the sleeve to be incompletely pressed into the tube, and even the tube may fall out of the clamp hole. Therefore, the ring is made of a non-metallic material, typically rubber, that has a higher friction coefficient with respect to the tube than the clamp, and the tube is passed coaxially through the ring, and then the ring is clamped inside the clamp hole. Since the ring is less slippery with respect to the tube than the clamp, if the ring is clamped in the gap between the clamp hole and the tube, it is possible to prevent not only the tube from falling out of the clamp hole, but also the sleeve from being incompletely pressed into the tube. Preferably, the surface of the clamp hole is covered with a rubber film (see Patent Document 2, for example), or the surface roughness of the hole is increased by blasting or the like (see Patent Document 3, for example). This makes the ring even less slippery inside the clamp hole. The ring also has the effect of preventing metal contamination of the tube that occurs due to direct contact between the tube and the clamp. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 10-332070 [Patent Document 2] Patent No. 3182690 [Patent Document 3] Patent No. 4580948 Summary of the Invention [Problem to be solved by the invention]

[0007] Since the ring is made of a non-metallic material, typically rubber, a decrease in the coefficient of friction due to aging is generally unavoidable. Therefore, as the number of years of use of the tube holding jig increases, the tube becomes more likely to slip against the ring. Also, if the difference between the inner diameter of the tube and the outer diameter of the bulging part of the sleeve is increased in order to improve the sealing between the tube and the sleeve, the sleeve must be pushed even harder into the open end of the tube when the sleeve is pressed into the tube, making the tube more likely to slip against the ring. In order to still prevent the tube from slipping even in these cases, it is necessary to strengthen the frictional force that the ring exerts on the tube. For example, this can be achieved by increasing the force that clamps the tube with a clamp to increase the normal force of the ring against the tube, or by increasing the width of the clamp and the ring in the longitudinal direction of the tube to increase the contact area between the tube and the ring. However, all of these measures result in an increase in the size of the jig. Alternatively, rubber with a higher coefficient of friction may be selected as the material for the ring. However, this measure increases the manufacturing cost of the ring.

[0008] The object of the present invention is to solve the above problems, and in particular to provide a tube holding jig that can improve the performance of holding the tube without slipping, while minimizing the increase in size and manufacturing costs. [Means for solving the problem]

[0009] A tube holding jig in one aspect of the present invention is a jig for holding a tube during an operation of forcing a member such as a sleeve into an open end of the tube, and includes a clamp and a ring. The clamp is configured to hold an object within a hole having a truncated cone surface. The ring has a higher coefficient of friction with respect to the tube than the clamp and has an outer peripheral surface having a truncated cone surface. The ring is further configured to be held coaxially within the hole of the clamp with the wider outer diameter side facing the wider diameter side of the hole, coaxially surrounding the tube with the wider outer diameter side facing the open end of the tube.

[0010] For example, the clamp may include two members pivotally connected to one another by a hinge, each of which includes a recess in the shape of a semi-frusto-conical surface and which are configured to overlap each other's surfaces upon pivoting about the hinge to form a hole in the shape of a semi-frusto-conical surface at the recess. Effect of the Invention

[0011] In the above-mentioned tube holding jig according to the present invention, the hole of the clamp and the outer circumferential surface of the ring sandwiched between the hole and the tube are both frustum conical instead of cylindrical in the conventional case. In this case, when the ring is pushed axially from the wide diameter side (hereinafter referred to as the "wide diameter side") of the frustum conical surface of the clamp hole to the narrow diameter side (hereinafter referred to as the "narrow diameter side") by the frictional force from the tube during the operation of pressing the sleeve onto the tube, the outer circumferential surface of the ring presses the surface of the clamp hole obliquely to the axial direction like a "wedge". Since the reaction force against this pressing force is also oblique to the axial direction, the outer circumferential surface of the ring is pushed back not only in the axial direction but also in the inward direction. Since this reaction force in the inward direction acts as a normal force against the tube, the frictional force that the ring can apply to the tube is strengthened. In other words, since the ring acts like a wedge in the gap between the tube and the hole of the clamp, the stronger the tube presses the ring in the axial direction, the less likely the tube is to slip against the ring. In this way, with just a relatively small design change to the tube holding jig - "making the clamp hole and the outer peripheral surface of the ring shaped like a truncated cone" - the present invention makes it possible to improve the performance of the tube holding jig by continuously holding the tube without slipping, without increasing the size or manufacturing costs.

[0012] The clamp hole may include an annular step protruding inward at the end with a narrower diameter (hereinafter referred to as the "narrow end"), and the ring may have an end face with a narrower outer diameter (hereinafter referred to as the "narrow end face") in close contact with the annular surface of the step. Furthermore, the ring may include an annular protrusion protruding in the axial direction from the narrow end face. This protrusion is sandwiched in the gap between the step and the tube. During the operation of pressing the sleeve onto the tube, the frictional force that the ring receives from the tube presses the narrow end face of the ring against the annular surface of the step of the clamp. This increases radial stress at the narrow end of the ring, further strengthening the normal force against the tube. This further strengthens the frictional force that the ring can exert on the tube.

[0013] The clamp hole may include an annular groove extending in the circumferential direction at the narrow end, and the ring may include an annular flange. The flange protrudes in the circumferential direction from the outer circumferential surface of the narrow end of the ring and is fitted into the groove of the clamp hole. Conversely, the clamp hole may include an annular protrusion protruding in the inward direction at the narrow end, and the ring may include an annular groove. The groove extends in the circumferential direction around the outer circumferential surface of the narrow end of the ring and is fitted into the protrusion of the clamp hole. In either case, during the pressing operation of the sleeve onto the tube, the frictional force that the ring receives from the tube presses the flange of the ring against the surface of the groove of the clamp, or the surface of the groove of the ring against the protrusion of the clamp. This increases the radial stress on the narrow side of the flange of the ring or on the wide side of the groove of the ring, further strengthening the normal force against the tube. This further strengthens the frictional force that the ring can exert on the tube.

[0014] The ring may include an annular groove extending circumferentially around its inner periphery, in which case the pressure exerted by the ring in the inward direction as a result of reaction force from the clamp is concentrated at the portions of the ring that contact the tube on either side of the annular groove, and these portions exert a stronger normal force on the tube, thereby further increasing the frictional force that the ring can exert on the tube. [Brief description of the drawings]

[0015] [Figure 1] 1 is a longitudinal sectional view of a pipe joint to which an embodiment of the present invention is directed. [Diagram 2] 1A, 1B, 1C, and 1D are top, front, bottom, and left side views, respectively, of a tool according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a perspective view of the tube holding jig shown in FIG. 2, showing the appearance when the clamp is open. [Figure 4] FIG. 3 is a perspective view of the tube holding jig shown in FIG. 2, showing the appearance when the clamp is closed. [Diagram 5]3 and 4, (b) is a left side view of the ring, and (c) is a vertical cross-sectional view taken along line cc shown in (a). [Figure 6] 2 immediately before the sleeve pressing mechanism presses the sleeve into the tube, (b) is a vertical cross-sectional view of the dashed line portion shown in (a), (c) is a front view of the sleeve pressing mechanism after the sleeve has been pressed into the tube, and (d) is a vertical cross-sectional view of the dashed line portion shown in (c). [Figure 7] 13 is a schematic vertical cross-sectional view of a clamp and a ring of a tube holding jig during an operation of a sleeve pressing mechanism for pressing a sleeve into a tube. FIG. [Figure 8] FIG. 6(a) is a front view of a simple clamp used to verify the effect of the ring shown in FIG. 5, and FIG. 6(b) is a perspective view of the components of the simple clamp. [Figure 9] 1A and 1B are longitudinal sectional views showing modified examples 1 and 2 of a clamp and a ring of a tube holding jig according to an embodiment of the present invention, respectively. [Figure 10] 13(a) and 13(b) are vertical cross-sectional views showing modified examples 3 and 4 of the clamp and ring of the tube holding jig according to the embodiment of the present invention, respectively. [Figure 11] FIG. 11 is a vertical cross-sectional view showing a fifth modified example of the ring according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [Structure of pipe joints]

[0017] 1 is a longitudinal cross-sectional view (i.e., a cross-sectional view along a plane including a central axis) of a pipe fitting 100 targeted by a tool according to an embodiment of the present invention. The pipe fitting 100 connects a tube 500 to another tube or to a fluid device such as a valve or a pump. The tube 500 is made of a non-metallic material, preferably a fluororesin such as polytetrafluoroethylene (PTFE) or perfluoroalkoxyalkane (PFA). The pipe fitting 100 includes a fitting body 110, a sleeve 120, and a union nut 130.

[0018] The joint body 110 is a cylindrical member made of a nonmetal, preferably a fluororesin such as polyvinylidene fluoride (PVDF), PTFE, or PFA. The end of the joint body 110 that is connected to the sleeve 120 (the left side in FIG. 1) is called the tip, and the opposite end is called the base end 119. The base end 119 is connected to another tube or fluid device. The tip has a double structure of an outer tube 111 and an inner tube 112. The outer tube 111 and the inner tube 112 coaxially protrude from the base end 119 in the same axial direction (the left side in FIG. 1). The outer tube 111 includes a male thread 114 on its outer circumferential surface. The tip 116 of the inner tube 112 is shorter than the tip 115 of the outer tube 111, includes an inclined surface 117 with respect to the axial direction (the left-right direction in FIG. 1), and the inner diameter increases as it moves away from the base end 119 of the joint body 110 in the axial direction (the left side in FIG. 1). A sleeve 120 is housed in the interior space of the outer cylinder 111 within the range from a tip 115 of the outer cylinder 111 to a tip 116 of the inner cylinder 112. An annular groove 118 is formed where the inner peripheral surface of the outer cylinder 111 and the outer peripheral surface of the inner cylinder 112 face each other.

[0019] The sleeve 120 is a cylindrical member made of a nonmetallic material, preferably a fluororesin such as PTFE or PFA, and is arranged coaxially with the joint body 110. Of the ends of the sleeve 120, the one connected to the tube 500 (the left end in FIG. 1) is called the tip end 121, and the one connected to the joint body 110 (the right end in FIG. 1) is called the base end 122. The tip end 121 of the sleeve 120 is press-fitted into the open end 501 of the tube 500, and the base end 122 is fitted into the inner tube 112 and the annular groove 118 of the joint body 111. As a result, the base end 119 of the joint body 110 communicates with the internal spaces of the inner tube 112, the sleeve 120, and the tube 500, forming a flow path for a fluid such as a chemical solution or ultrapure water.

[0020] The tip 121 of the sleeve 120 includes a bulge 123. The bulge 123 is a portion whose outer diameter gradually increases or decreases depending on the position in the axial direction (left-right direction in FIG. 1), and includes a portion where the outer diameter is maximum, i.e., a peak, in the center in the axial direction. Since the outer diameter of this peak is larger than the inner diameter of the tube 500, the bulge 123 is pushed into the open end 501 of the tube 500, expanding the open end 501 from the inside. The elastic force of the tube 500 that resists this expansion acts so that the open end 501 of the tube 500 embraces the bulge 123 of the sleeve 120, so that the open end 501 is firmly fixed to the tip 121 of the sleeve 120 and the gap between the open end 501 and the tip 121 is sealed.

[0021] The base end 122 of the sleeve 120 includes an annular protrusion 124 and an annular groove 125. The annular protrusion 124 protrudes coaxially from the entire circumference of the base end 122 in the axial direction (to the right in FIG. 1 ) and is press-fitted into the annular groove 118 of the joint body 110. That is, since the inner diameter of the annular protrusion 124 is slightly smaller than the outer diameter of the inner tube 112 of the joint body 110, the inner peripheral surface of the annular protrusion 124 and the outer peripheral surface of the inner tube 112 are in close contact with each other. The annular groove 125 of the sleeve 120 is coaxially disposed inside the base end of the annular protrusion 124. The tip 116 of the inner tube 112 of the joint body 110 is inserted into the annular groove 125. The surface of the annular groove 125 includes a portion inclined in the same direction as the inclined surface 117 of the tip 116 of the inner tube 112. This portion is in contact with the inclined surface 117 of the inner tube 112.

[0022] The union nut 130 is a cylindrical member made of a nonmetallic material, preferably a fluororesin such as PTFE, PFA, or PVDF, and coaxially surrounds the joint body 110, the sleeve 120, and the tube 500. The end of the union nut 130 that is closer to the joint body 110 (the right end in FIG. 1) is called the tip end 131, and the opposite end (the left end in FIG. 1) is called the base end 132. The tube 500 is coaxially inserted into the base end 132. The tip end 131 has a female thread 134 on its inner circumferential surface, and the base end 132 has a step 135 on its inner circumferential surface. The female thread 134 meshes with the male thread 114 of the joint body 110. The step 135 has an inner diameter narrower than that of the female thread 134, and is in contact with the portion of the tube 500 that is expanded by the bulging portion 123 of the sleeve 120. As a result, when the female thread 134 of the union nut 130 is screwed into the male thread 114 of the joint body 110, pressure from the union nut 130 is applied to the tube 500 from the step portion 135 and transmitted through the sleeve 120 to the annular protrusion 124 and annular groove 125 of the sleeve 120. As a result, the inner circumferential surface of the annular protrusion 124 further increases the pressure on the outer circumferential surface of the inner tube 112 of the joint body 110, and the surface of the annular groove 125 is pressed against the inclined surface 117 of the inner tube 112 of the joint body 110 without any gaps. In this way, the gap between the joint body 110 and the sleeve 120 is sealed. [Tool structure]

[0023] 2(a), (b), (c), and (d) are a top view, a front view, a bottom view, and a left side view, respectively, of a tool 200 according to an embodiment of the present invention. The tool 200 is dedicated to the press-fitting operation of the sleeve 120 into the tube 500, and includes a main body 210, a tube holding jig 300, and a sleeve pressing mechanism 400. -Main unit-

[0024] The main body 210 is a long and thin rectangular plate made of metal such as an aluminum alloy. A tube holding jig 300 is fixed to the upper surface of one end (the left end in FIG. 2) 211 of the main body 210 by, for example, a bolt 212. A long and thin slit 213 is opened from the center of the main body 210 to the other end (the right end in FIG. 2), and a sleeve pressing mechanism 400 is fitted into the slit 213 so as to be slidable along the slit. -Tube holding jig-

[0025] Figures 3 and 4 are both perspective views of tube holding jig 300. Tube holding jig 300 includes a clamp 310 and a ring 330. Figure 3 shows the appearance of clamp 310 when it is open, and Figure 4 shows the appearance of clamp 310 when it is closed. <Clamp>

[0026] The clamp 310 has a rectangular plate shape as a whole, and includes a fixed part 311 and a movable part 321. The fixed part 311 and the movable part 321 are rectangular plates made of metal such as an aluminum alloy, and preferably have the same thickness. The fixed part 311 includes a recess 312 (hereinafter referred to as the "fixed recess") on the top surface, and the movable part 321 includes a recess 322 (hereinafter referred to as the "movable recess") on the bottom surface. The fixed recess 312 and the movable recess 322 are semicircular truncated cone shapes of the same size, and the axial direction is perpendicular to the plate surface 313 of the fixed part 311 or the plate surface 323 of the movable part 321. In both recesses 312 and 322, the generatrix forms an inclination angle θc (0°<θc<90°) with respect to the axial direction, so that the diameter increases from a minimum value Dmn to a maximum value Dmx as it moves from one end (the left end in FIG. 3) to the other end (the right end in FIG. 3) in the axial direction. Preferably, each recess 312, 322 is covered with a rubber membrane 340, such as nitrile rubber (NBR). The membrane 340 is glued to each recess 312, 322.

[0027] The fixed part 311 is fixed with its bottom surface in close contact with the upper surface of one end 211 of the main body 210. The end of the bottom surface of the movable part 321 is swingably connected to the end of the upper surface of the fixed part 311 by a hinge 314, and can be displaced to an open position shown in FIG. 3 and a closed position shown in FIG. 4 by swinging around the hinge 314. In the open position, the clamp 310 opens. That is, the angle that the movable part 321 forms with respect to the fixed part 311 becomes maximum. Therefore, since the movable recess 322 is far away from the fixed recess 312, the tube 500 and the ring 330 can be placed in the fixed recess 312 or the tube 500 and the ring 330 can be taken out from the fixed recess 312. In the closed position, the clamp 310 closes. That is, the bottom surface of movable part 321 overlaps with the upper surface of fixed part 311, so that plate surface 313 of fixed part 311 and plate surface 323 of movable part 321 form a single flat surface, and fixed recess 312 and movable recess 322 form a space (hereinafter referred to as a "hole") having a nearly perfect truncated cone surface. When tube 500 and ring 330 are placed in fixed recess 312, tube 500 and ring 330 are sandwiched in the hole formed by fixed recess 312 and movable recess 322.

[0028] The fixed part 311 includes a rotating shaft 315, a latch 316, and a lever 317 on the opposite side of the hinge 314 with the fixed recess 312 in between. All of these are rod-shaped members made of metal such as aluminum alloy or stainless steel. The rotating shaft 315 penetrates the fixed part 311 perpendicularly to the plate surface 313 and can rotate around its own central axis. A protrusion 318 protrudes in the axial direction from one end of the rotating shaft 315 (the left end in Figs. 3 and 4). Since the protrusion 318 is eccentric with respect to the rotating shaft 315, when the rotating shaft 315 rotates, it is displaced around the central axis. A base end 316a of the latch 316 is rotatably connected to the protrusion 318. The tip end of the latch 316 includes a hook portion 316b. The lever 317 is connected to the other end of the rotating shaft 315 (the right end in Figs. 3 and 4) perpendicularly thereto. As the lever 317 is raised and lowered to rotate the rotating shaft 315, the projection 318 and the base end 316a of the latch 316 are displaced. For example, when the lever 317 is raised as shown in Fig. 3, the projection 318 and the base end 316a of the latch 316 rise and move away from the one end 211 of the main body 210, and when the lever 317 is lowered as shown in Fig. 4, they fall and move closer to the one end 211 of the main body 210.

[0029] The movable part 321 includes a protrusion 324 on the opposite side of the hinge 314 with the movable recess 322 interposed therebetween. When the clamp 310 is closed as shown in FIG. 4, the protrusion 324 is located almost directly above the projection 318 of the rotating shaft 315. At this time, if the lever 317 is raised as shown in FIG. 3, the latch 316 can be rotated around the base end 316b to hook the hook 316a to the protrusion 324 as shown in FIG. 4. In this state, if the lever 317 is further lowered as shown in FIG. 4, the protrusion 318 and the base end 316a of the latch 316 are lowered, and the hook 316a is pulled downward and pressed against the protrusion 324. This makes it difficult for the latch 316 to come off the protrusion 324, so that the movable part 321 is locked in the closed position. <Ring>

[0030] 5A and 5B are a perspective view and a left side view of the ring 330, respectively, and FIG. 5C is a longitudinal cross-sectional view of the ring 330 taken along the line cc shown in FIG. 5A. The ring 330 is a cylindrical member made of a nonmetallic material, preferably rubber such as urethane. The material of the ring 330 has a higher friction coefficient with respect to the material of the tube 500 than the material of the clamp 310. The inner peripheral surface 333 of the ring 330 is cylindrical and has a constant inner diameter Di. On the other hand, the outer peripheral surface 334 of the ring 330 is truncated cone, and the generatrix forms an inclination angle θr (0°<θr<90°) with respect to the axial direction (left-right direction in FIG. 5C), so that the outer diameter increases from a minimum value Don to a maximum value Dox as it moves from one end to the other end in the axial direction (from the left end to the right end in FIG. 5C).

[0031] Ring 330 has an axial cut 331 at one location on its circumference, and a living hinge 332 on the opposite side of the central axis of ring 330. As a result, cut 331 can be opened and closed, so that tube 500 can be easily inserted into ring 330 through cut 331, and tube 500 can be easily removed from ring 330. Furthermore, it is possible to insert tube 500 with an outer diameter larger than the inner diameter Di of ring 330 into ring 330.

[0032] As shown in FIG. 4, the ring 330 coaxially surrounds the tube 500 with its wider outer diameter side (the right side in FIG. 4; hereinafter referred to as the "wide diameter side") facing the open end 501 of the tube 500, and is placed in the fixed recess 312 with its wider diameter side facing the wider diameter side of the fixed recess 312 (the right side in FIG. 4; hereinafter referred to as the "wide diameter side"). Therefore, when the clamp 310 is closed, the ring 330 is sandwiched in the gap between each recess 312, 322 and the tube 500. Preferably, the minimum outer diameter Don of the ring 330 is equal to or greater than the minimum diameter Dmn of each recess 312, 322 (including the membrane 340) (Don≧Dmn), and the inclination angle θr of the generatrix of the outer circumferential surface 333 of the ring 330 is equal to or greater than the inclination angle θc of the generatrix of each recess 312, 322 (θr≧θc). As a result, when lever 314 is lowered with clamp 310 closed, the force of latch 316 pulling protrusion 324 downward to lock movable part 321 to fixed part 311 causes the entire outer circumferential surface 333 of ring 330 to adhere tightly to both fixed recess 312 and movable recess 322. [Sleeve pressing mechanism]

[0033] 6(a) is a front view showing a state immediately before the sleeve pressing mechanism 400 presses the sleeve 120 into the tube 500, and (b) is a vertical cross-sectional view of the dashed line portion shown in (a). Fig. 6(c) is a front view showing a state in which the sleeve pressing mechanism 400 has completely pressed the sleeve 120 into the tube 500, and (d) is a vertical cross-sectional view of the dashed line portion shown in (c).

[0034] The sleeve pressing mechanism 400 is a mechanism for moving the sleeve 120 in the axial direction by using a rack and pinion, and includes a lever 410 and a support shaft 420. A rotating shaft 411 of the lever 410 is connected to a pinion (not shown), and the pinion can rotate in both directions by raising and lowering the lever 410. The support shaft 420 can translate in the axial direction (left and right direction in FIG. 6) and is arranged coaxially with the fixed recess 312 of the tube holding jig 300. A rack 421 is engraved on the outer circumferential surface of the support shaft 420 from its center to its base end (right end in FIG. 6), and is engaged with the pinion. As a result, the support shaft 420 translates in the axial direction with the rotation of the pinion. For example, when the lever 410 is tilted to the left as shown in FIG. 6(c), the support shaft 420 advances to the left, and then, when the lever 410 is raised as shown in FIG. 6(a), the support shaft 420 retreats to the right. A tip (the left end in FIG. 6) 422 of the support shaft 420 is configured so that the sleeve 120 can be coaxially fitted thereon.

[0035] As shown in FIG. 6(a), the tube holding jig 300 holds the tube 500 between the fixed part 311 and the movable part 321 with the open end 501 facing the sleeve pressing mechanism 400. Meanwhile, the sleeve pressing mechanism 400 holds the sleeve 120 by covering the tip 422 of the support shaft 420. Since the fixed recess 312 and the support shaft 420 are coaxial, the tube 500 and the sleeve 120 face each other coaxially, as shown in FIG. 6(b). In this state, the operator pushes down the lever 410 to move the support shaft 420 forward toward the tube holding jig 300. Due to the driving force of the support shaft 420 at this time, the tip 121 of the sleeve 120 is pushed into the open end 501 of the tube 500, as shown in FIG. 6(c) and FIG. 6(d), and the bulging part 123 pushes the open end 501 wide. This fixes the sleeve 120 in the open end 501. After that, the operator raises the lever 410 to the right and moves the support shaft 420 back from the tube holding jig 300. At this time, the tip 422 of the support shaft 420 comes out of the sleeve 120, so that the sleeve 120 is left at the open end 501 of the tube 500. [Why the clamp hole and the outer circumference of the ring are shaped like a truncated cone]

[0036] 7 is a schematic vertical cross-sectional view of the clamp 310 and the ring 330 during the sleeve pressing mechanism 400 pressing the sleeve 120 into the tube 500. When the sleeve 120 is pressed into the open end 501 of the tube 500, the tube 500 receives a force F0 in the axial direction (leftward in FIG. 7), and the outer peripheral surface 502 of the tube 500 applies a friction force F1 in the axial direction (leftward in FIG. 7) to the inner peripheral surface 334 of the ring 330. At this time, the wide diameter side (rightward in FIG. 7) of the fixing recess 312 of the tube holding jig 300 faces the open end 501 of the tube 500, and the wide diameter side (rightward in FIG. 7) of the ring 330 also faces the open end 501 of the tube 500. Therefore, the ring 330 acts like a "wedge," as described below.

[0037] Since the outer peripheral surface 333 of the ring 330, the fixed recess 312, and the movable recess 322 are inclined with respect to the axial direction, a pressing force F2 acts from the outer peripheral surface 333 to each of the recesses 312 and 322 in an oblique direction with respect to the axial direction (upper left direction in FIG. 7) in accordance with the axial friction force F1. The reaction force F3 is also oblique with respect to the axial direction (lower right direction in FIG. 7), and includes a component F4 in the inner peripheral direction (downward direction in FIG. 7). This component F4 strengthens the normal force F5 from the inner peripheral surface 334 of the ring 330 to the outer peripheral surface 502 of the tube 500. As a result, the friction force F6 in the axial direction (rightward in FIG. 7) that the inner peripheral surface 334 of the ring 330 receives from the outer peripheral surface 502 of the tube 500 is strengthened, and the tube 500 becomes less likely to slide in the axial direction (leftward in FIG. 7) relative to the ring 300.

[0038] As described above, if the hole of clamp 310 and outer peripheral surface 333 of ring 330 have a truncated cone shape, ring 330 acts like a wedge and strengthens friction force F6 against tube 500. This effect (hereinafter referred to as the "wedge effect") has been verified by the following experiment.

[0039] FIG. 8(a) is a front view of the simple clamp 600 used to verify the wedge effect of the ring 330. The simple clamp 600 is a combination of two plate-shaped members 610 of the same shape and size. FIG. 8(b) is a perspective view of the plate-shaped member 610. The plate-shaped member 610 is a rectangular plate made of a metal such as an aluminum alloy, and has a constant thickness, for example, 30 mm. The plate-shaped member 610 includes a recess 612 in the shape of a semicircular truncated cone surface on an upper surface 611. The axial direction of the recess 612 is perpendicular to a plate surface 613 of the plate-shaped member 610. The recess 612 has, for example, a minimum radius Rmn of 10.3 mm, a maximum radius Rmx of 13.5 mm, and an inclination angle θc of the generatrix with respect to the axial direction of 4°. The recess 612 is covered with a rubber film (not shown) such as NBR. The film has a thickness of 3.35 mm to 6.50 mm, and is bonded to the recess 612. The plate-like member 610 has through holes 614 at both ends in the longitudinal direction, and female threads are cut in the through holes. When two plate-like members 610 are stacked upside down, one on the other, as shown in FIG. 8(a), the plate surfaces 613 of the upper and lower plate-like members 610 form a single flat surface, and the recesses 612 of the two plate-like members 610 form holes with a nearly perfect truncated cone surface. Furthermore, each through hole 614 of the upper plate-like member 610 is coaxially aligned with the through hole 614 on the same side of the lower plate-like member 610. With the ring 330 and the tube 500 coaxially sandwiched between the two recesses 612, a bolt (not shown) is screwed into each through hole 614. For example, the nominal diameter of the bolt is M8, and the tightening torque is 2.0 Nm. In this way, the ring 330 and the tube 500 are clamped together by the two recesses 612, so that the outer peripheral surface 333 of the ring 330 is in close contact with the recess 612 (or more precisely, the rubber membrane covering it), and the inner peripheral surface 334 of the ring 330 is in close contact with the outer peripheral surface of the tube 500.

[0040] The tube 500 used in the experiment had an outer diameter of 12 mm, and the ring 330 had an axial length of 30 mm, a minimum outer diameter Dmn of 19 mm, a maximum outer diameter Dmx of 25 mm, an inclination angle θr of the generatrix with respect to the axial direction of 6°, and an inner diameter of 12 mm.

[0041] Using a compression tester or the like, open end 501 of tube 500 held by simple clamp 600 was compressed in the axial direction at a constant speed of 1.5 mm / min for 120 seconds, and the load F0 (hereinafter referred to as "holding force") was determined when tube 500 began to slip against ring 630. As a result, the holding force was 114.4 N.

[0042] The same experiment was also carried out on a simple tool that imitated a conventional clamp and ring. That is, the clamp and ring differ from those described above only in the following points: the concave portion of the clamp is semi-cylindrical with a radius of 13.5 mm; the outer and inner surfaces of the ring are both cylindrical with an outer diameter of 25 mm and an inner diameter of 12 mm. The holding force F0 of this simple tool was 109.2 N. Therefore, it was found that the holding force of the simple clamp 600 is 5.2 N stronger than that of this simple tool, that is, the holding force is increased by 4.8%. [Advantages of the embodiment]

[0043] In the tube holding jig 300 according to the above embodiment of the present invention, the fixed recess 312 and the movable recess 322 of the clamp 310 are both semicircular truncated cone-shaped, and the outer circumferential surface 333 of the ring 330 is a truncated cone-shaped surface. In this case, during the press-fitting operation of the sleeve 120 into the tube 500, when the ring 330 is pressed in the axial direction from the wide-diameter side to the narrow-diameter side of the truncated cone-shaped surfaces of the recesses 312 and 322 by the frictional force F1 between the ring 330 and the tube 500, the ring 330 presses the recesses 312 and 322 obliquely with respect to the axial direction with the outer circumferential surface 333 like a "wedge". The outer circumferential surface 333 of the ring 330 is pressed inward by the reaction force F3 against this pressing force F2. This pressing force F4 in the inner circumferential direction acts on the tube 500 as a normal force F5, so that the frictional force F6 of the ring 330 against the tube 500 is strengthened. That is, due to the wedge effect of ring 330, the stronger tube 500 presses ring 330 in the axial direction, the less likely tube 500 will slip relative to ring 330. Thus, with only a relatively small change in design, that is, by making both recesses 312, 322 into semicircular truncated cone shapes and making outer circumferential surface 333 of ring 330 into a truncated cone shape, tube holding jig 300 can achieve improved performance of continuing to hold tube 500 without slipping, while suppressing increases in size and manufacturing costs. [Variations]

[0044] (1) The sleeve 120 shown in Fig. 1 is merely one example. That is, the sleeve may have various other shapes. Also, depending on the type of pipe joint, the member pushed into the open end 501 of the tube 500 may be the main body of the pipe joint instead of the sleeve 120.

[0045] (2) Tube holding jig 300 shown in Figures 3 and 4 is merely one example. For example, fixed part 311 and movable part 321 may be fastened to each other like simple clamp 600, instead of the locking mechanism including rotating shaft 315, latch 316, and lever 317. Fixed part 311 and movable part 321 may be shaped like a cylinder split vertically into two, instead of being plate-shaped, and each of the inner circumferential surfaces may be semicircular truncated cone-shaped.

[0046] 5, ring 330 can be opened and closed by notches 331 and living hinges 332. However, if ring 330 has a sufficiently high elasticity such that tube 500 passed through ring 330 can be slid by hand until ring 330 is sandwiched between fixed part 311 and movable part 321, notches 331 and living hinges 332 may be omitted and outer circumferential surface 333 of ring 330 may be a completely closed truncated cone surface.

[0047] (4) The ring 330 shown in FIG. 5 is made of rubber. However, the material of the ring 330 is not limited to this, and may be other resin or nonmetallic material other than resin, as long as the friction coefficient against the tube 500 is higher than that of the clamp 310. Similarly, the film 340 covering the fixed recess 312 and the movable recess 322 of the tube holding jig 300 may be nonmetallic material other than rubber, as long as the friction coefficient against the ring 330 is higher than that of both recesses 312 and 322. Furthermore, instead of the film 340, the surface roughness of each recess 312 and 322 may be increased by blasting or the like. Moreover, instead of the film 340, a film or layer made of a material having a friction coefficient against the tube 500 higher than that of the clamp 310 may be integrated with the surface of each recess 312 and 322 by overmolding, insert molding, or the like.

[0048] 5, the fixed recess 312, the movable recess 322, and the outer circumferential surface 333 of the ring 330 are all smooth. Alternatively, these may include irregularities as described below.

[0049] FIG. 9A is a longitudinal cross-sectional view showing a first modified example of the clamp 310 and the ring 330 according to the embodiment of the present invention. In the first modified example, the fixed recess 312 and the movable recess 322 each include a semicircular step 381 protruding inward on the narrower diameter side (the left side in FIG. 9A, hereinafter referred to as the "narrower diameter side"). When the clamp 310 is closed, the step 381 of both recesses 312 and 322 forms a complete ring shape. The inner diameter of the ring shape is wider than the outer diameter of the tube 500. Meanwhile, the ring 330 includes an annular protrusion 382 protruding in the axial direction (left side in FIG. 9A) from the end face on the narrower diameter side (the left end face in FIG. 9A, hereinafter referred to as the "narrower diameter end face"). The protrusion 382 closes the gap between the step 381 and the tube 500. During the operation of press-fitting the sleeve 120 into the open end 501 of the tube 500, the narrow diameter end face of the ring 330, except for the projection 382, ​​is pressed against the step portions 381 of both recesses 312, 322. At this time, inside the ring 330, the axial stress FS (leftward in FIG. 9(a)) caused by the frictional force F1 from the outer circumferential surface 502 of the tube 500 is concentrated in the vicinity of the narrow diameter end face. As a result, the radial stress increases in that vicinity, and the normal force F5 against the tube 500 becomes even stronger. Thus, the frictional force F6 of the ring 330 against the tube 500 becomes even stronger.

[0050] FIG. 9B is a longitudinal cross-sectional view showing a second modified example of the clamp 310 and the ring 330 according to the embodiment of the present invention. In the second modified example, the fixed recess 312 and the movable recess 322 each include a semicircular step 381 protruding inward on the narrow diameter side (the left end side in FIG. 9B). When the clamp 310 is closed, the steps 381 of both recesses 312 and 322 form a complete ring shape. The inner diameter of the ring shape is almost equal to the outer diameter of the tube 500, unlike the inner diameter in the first modified example shown in FIG. 9A. Therefore, the film 340 covering the recesses 312 and 322 directly contacts the outer circumferential surface 502 of the tube 500. In this case, the ring 330 makes the entire narrow diameter end surface contact the ring surface formed by the steps 381 of the recesses 312 and 322. During the press-fitting of the sleeve 120 into the tube 500, the entire narrow diameter end face of the ring 330 is pressed against the step portions 381 of both recesses 312, 322. At this time, inside the ring 330, the axial stress FS (leftward in FIG. 9(b)) associated with the frictional force F1 from the outer circumferential surface 502 of the tube 500 is concentrated in the vicinity of the narrow diameter end face. As a result, the radial stress increases in that vicinity, further increasing the normal force F5 against the tube 500. Thus, the frictional force F6 of the ring 330 against the tube 500 is further increased.

[0051] 10(a) is a longitudinal cross-sectional view showing a third modified example of the clamp 310 and the ring 330 according to the embodiment of the present invention. In the third modified example, the fixed recess 312 and the movable recess 322 each include a semicircular groove 383 extending in the circumferential direction on the narrow diameter side (the left end side in FIG. 10(a)), and the ring 330 includes a circular flange 384. The flange 384 protrudes in the outer circumferential direction from the outer circumferential surface of the narrow diameter end (the left end side in FIG. 10(a)) of the ring 330, and is fitted into the grooves 383 of each of the recesses 312, 322. During the press-fitting operation of the sleeve 120 into the tube 500, the flange 384 of the ring 330 is pressed against the surfaces of the grooves 383 of each of the recesses 312, 322. At this time, inside the ring 330, the stress FS in the axial direction (leftward in FIG. 10(a)) caused by the frictional force F1 from the outer circumferential surface of the tube 500 is concentrated on the narrow diameter side (left end side in FIG. 10(a)) of the flange 384 pressed against the surface of the groove 383, increasing the radial stress. As a result, the normal force F5 against the tube 500 becomes stronger, and the frictional force F6 of the ring 330 against the tube 500 becomes stronger.

[0052] 10B is a longitudinal cross-sectional view showing a fourth modified example of the clamp 310 and the ring 330 according to the embodiment of the present invention. In the fourth modified example, the fixed recess 312 and the movable recess 322 each include a semicircular ring-shaped protrusion 385 protruding inwardly on the narrow diameter side (left side in FIG. 10B), and the ring 330 includes an annular groove 386. The groove 386 extends in the circumferential direction on the outer circumferential surface of the narrow diameter end of the ring 330, and the protrusions 385 of each of the recesses 312, 322 are fitted into the groove 386. During the press-fitting operation of the sleeve 120 into the tube 500, the wide diameter side (right side in FIG. 10B) of the ring 330 is pressed against the groove 386 and against the protrusions 385 of each of the recesses 312, 322. At this time, inside the ring 330, the stress FS in the axial direction (leftward in FIG. 10(b)) associated with the frictional force F1 from the outer circumferential surface of the tube 500 is concentrated on the portion pressed against the protrusion 385, increasing the stress in the radial direction. As a result, the normal force F5 against the tube 500 becomes stronger, and the frictional force F6 of the ring 330 against the tube 500 becomes stronger.

[0053] (6) As shown in Fig. 5, the inner peripheral surface 334 of the ring 330 is smooth. Alternatively, the inner peripheral surface may include irregularities as described below.

[0054] FIG. 11 is a vertical cross-sectional view showing a fifth modified example of the ring 330 according to the embodiment of the present invention. In the fifth modified example, the inner peripheral surface of the ring 330 includes a plurality of annular grooves 387 extending in the circumferential direction. The annular grooves 387 are, for example, square grooves, and are arranged at equal intervals in the axial direction of the ring 330 (the left-right direction in FIG. 11). During the press-fitting operation of the sleeve 120 onto the tube 500, the stress in the inner peripheral direction inside the ring 330 is concentrated on the portions 388 of the inner peripheral surface of the ring 330 that contact the outer peripheral surface of the tube 500 on both sides of the annular groove 387 due to the reaction force F3 that the outer peripheral surface of the ring 330 receives from the recesses 312 and 322 of the clamps 310 and 320. As a result, the normal force F5 against the tube 500 is stronger than when the inner peripheral surface of the ring 330 does not have the annular groove 387. Thus, the friction force F6 of the ring 330 against the tube 500 is further strengthened. [Explanation of symbols]

[0055] 300 Tube holding fixture 310 Clamp 311 Fixed part 312 Fixed recess 321 Moving parts 322 Movable recess 330 Ring 333 Ring Outer Surface 500 tubes

Claims

1. A tool for holding a tube during the act of forcing a member into an open end of the tube, comprising: A clamp configured to clamp an object within a truncated cone-shaped hole; a ring having an outer peripheral surface in the shape of a truncated cone, the outer peripheral surface having a higher coefficient of friction with respect to the tube than the clamp; Equipped with The ring is configured to be coaxially sandwiched within the clamp hole with its wider outer diameter side facing the wider diameter side of the hole, coaxially surrounding the tube with its wider outer diameter side facing the open end of the tube. A tube holding jig characterized by:

2. The clamp is Two members pivotally connected to each other by a hinge Including, The two members are: Each of the recesses includes a semicircular truncated cone shape on the surface. The surfaces are overlapped with each other by swinging about the hinge to form the truncated cone-shaped hole in the recess. The tube holding jig according to claim 1 .

3. the clamp hole includes an annular step at a narrower diameter end thereof, the step protruding inwardly; The end face of the ring having a narrower outer diameter is in close contact with the annular surface of the step portion.

2. The tube holding jig according to claim 1 .

4. The ring is An annular protrusion that protrudes in the axial direction from the end face with a narrower outer diameter and is sandwiched in the gap between the step portion and the tube. Includes 4. The tube holding jig according to claim 3.

5. the clamp bore including a circumferentially extending annular groove at a narrower diameter end; The ring is An annular flange that protrudes in the outer circumferential direction from the outer circumferential surface of the end portion having a narrower outer diameter and is fitted into the groove. Includes 2. The tube holding jig according to claim 1 .

6. the clamp hole includes an annular projection at a narrower diameter end thereof, the annular projection projecting inwardly; The ring is An annular groove extending in the circumferential direction on the outer circumferential surface of the end portion having a narrower outer diameter and into which the protrusion is fitted. Includes 2. The tube holding jig according to claim 1 .

7. The ring includes an annular groove extending circumferentially about its inner periphery.

2. The tube holding jig according to claim 1 .

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