Forming jig and tube

Abstract

To provide a forming jig that can bend a tube into a desired shape while suppressing an increase in operation time and damage to the tube, and a tube manufactured using the same.SOLUTION: A groove 11 is formed in a shape corresponding to a bending processing shape of a tube 6, and the tube 6 is fitted therein. Protrusions 3 are installed on an inner wall surface 11a of the bend of the groove 11, within a prescribed range including a change point P1 of the shape of the groove 11 and within a prescribed range including a change point P2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a forming jig for bending a tube, and to a tube manufactured using the same. [Background technology]

[0002] A known technique for bending a tube is to use a forming jig in which a groove corresponding to the desired shape of the bend is formed. In this technique, a tube made of thermoplastic resin is heated while being fitted into the groove of the forming jig, and then cooled to be bent.

[0003] The groove of the forming jig described above is formed to be wider than the design value of the outer diameter of the tube, taking into consideration the tolerance of the outer diameter of the tube and the fitment of the tube, which results in a gap between the tube fitted in the groove and the wall surface of the groove.

[0004] The tube tries to maintain a straight shape due to its elasticity, but if there is a gap between the tube and the wall of the groove, the tube will not bend according to the shape of the groove and may become flattened and buckle.

[0005] In response to this, Patent Document 1 discloses a technique for bending a tube by fitting a tube into a groove of a conductive base (forming jig) into which a conductive core rod having a shape that matches the desired bent shape is inserted, passing a high-frequency current between the core rod and the base to heat the tube, and then stopping the current to cool the tube. This technique makes it possible to bend the tube while suppressing buckling. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 9-29831 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the technique of Patent Document 1 requires the insertion and removal of a core rod into and from the tube, which increases the time required for bending the tube, and there is also a risk that the tube may be damaged when the core rod is inserted and removed.

[0008] The present invention has been made in consideration of the above, and has an object to provide a forming jig that can bend a tube into a desired shape while minimizing increases in working time and damage to the tube, and a tube manufactured using the same. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the forming jig of the present invention is characterized in that it is formed into a shape corresponding to the bending shape of the tube, and has a groove into which the tube is fitted, and a protrusion portion arranged on the inner wall surface of the bend of the groove within a predetermined range including the point at which the shape of the groove changes.

[0010] The tube of the present invention is characterized in that it is manufactured using the forming jig of the present invention. Effect of the Invention

[0011] According to the present invention, it is possible to provide a forming jig that can bend a tube into a desired shape while suppressing an increase in working time and damage to the tube, and a tube manufactured using the same. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a plan view showing a configuration of a forming jig according to the embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Diagram 3] 3 is a diagram showing a state in which a tube having an outer diameter different from that of the tube in FIG. 2 is fitted into a groove. [Figure 4]FIG. 13 is a diagram showing the state in which a tube with a different outer diameter is fitted into the groove. [Diagram 5] FIG. 13 is a diagram showing how a tube is guided into a groove. [Figure 6] 2 is a diagram showing an example of a state in which a tube is fitted into the forming jig shown in FIG. 1 with each protrusion omitted. FIG. [Figure 7] 13 is an explanatory diagram of tube buckling that occurs when a protrusion is positioned outside a predetermined range. FIG. [Figure 8] 13A and 13B are diagrams showing an example of a forming jig on which an additional protrusion is arranged. [Figure 9] 13A to 13C are diagrams showing examples of forming jigs corresponding to other bending shapes. [Figure 10] 10 is a diagram showing an example of a state in which a tube is fitted into the forming jig shown in FIG. 9 with each protrusion omitted. FIG. [Figure 11] 13A to 13C are diagrams showing examples of forming jigs corresponding to still other bending shapes. [Figure 12] 12 is a diagram showing an example of a state in which a tube is fitted into the forming jig shown in FIG. 11 with the protrusions omitted. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The same or equivalent parts and components are denoted by the same or equivalent reference numerals throughout the drawings.

[0014] The following embodiments are examples of devices for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not limit the material, shape, structure, arrangement, etc. of each component to those described below. The technical idea of ​​the present invention can be modified in various ways within the scope of the claims.

[0015] Fig. 1 is a plan view showing the configuration of a forming jig according to an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along line AA in Fig. 1.

[0016] As shown in FIG. 1, a forming jig 1 according to this embodiment includes a jig body 2 and two protrusions 3. The forming jig 1 includes a jig body 2 and two protrusions 3. The jig body 2 has a groove 3a.

[0017] This forming jig 1 is used for bending a tube 6. The tube 6 is made of a thermoplastic resin such as a fluororesin.

[0018] The jig body 2 is formed in a rectangular parallelepiped shape. The jig body 2 is made of a metal such as an aluminum alloy. The jig body 2 has a groove 11 into which the tube 6 to be bent is fitted.

[0019] The groove 11 is formed by digging into the surface 2a of the jig body 2. As shown in Fig. 2, the groove 11 has wall surfaces 11a and 11b that face each other and are perpendicular to the surface 2a, and a bottom surface 11c that is parallel to the surface 2a. In a plan view, the groove 11 is formed into a shape that corresponds to the bending shape of the tube 6. The width of the groove 11 (the distance between the wall surfaces 11a and 11b) is larger than the outer diameter of the tube 6 that has the largest outer diameter among the tubes 6 to be bent by the forming jig 1.

[0020] Here, the bent shape of the tube 6 includes curved portions such as circular arcs and shape change points. Shape change points include a boundary point between a straight line portion and a curved portion, a boundary point between two consecutive curved portions that bend in opposite directions, a boundary point between two consecutive curved portions with different radii of curvature, etc.

[0021] In the example of Fig. 1, the bent shape of the tube 6 is a J-shape consisting of an arc-shaped curved portion and two straight portions connected to one end and the other end of the curved portion. In accordance with this bent shape, the groove 11 has an arc-shaped curved portion 16, a straight straight portion 17 connected to one end of the curved portion 16, and a straight straight portion 18 connected to the other end of the curved portion 16. The groove 11 also includes change points P1 and P2 in its shape. The change point P1 is the boundary point between the curved portion 16 and the straight portion 17. The change point P2 is the boundary point between the curved portion 16 and the straight portion 18.

[0022] The protrusions 3 regulate the width of the groove 11 and press the tube 6 against the wall surface 11b on the outside of the curve of the groove 11. In the example of Fig. 1, two protrusions 3 are provided corresponding to the change points P1 and P2, respectively. The protrusions 3 are provided on the wall surface 11a on the inside of the curve of the groove 11 within a predetermined range including the change point P1 and within a predetermined range including the change point P2.

[0023] The predetermined range in which the protrusion 3 corresponding to the change point P1 is arranged is a range in which the central angle at the center of curvature C of the curved portion 16 is equal to or smaller than a predetermined angle α on both sides of the change point P1 (see FIG. 7), as will be described later. The same is true for the predetermined range in which the protrusion 3 corresponding to the change point P2 is arranged. In the example of FIG. 1, the two protrusions 3 are arranged at the positions of the change points P1 and P2, respectively.

[0024] As shown in FIG. 2, the protrusion 3 includes a base plate 21, a pressing plate 22, a rotating shaft 23, and a compression spring 24.

[0025] The base plate 21 supports the pressing plate 22 via a compression spring 24. The base plate 21 is attached to the wall surface 11a. The base plate 21 extends from the upper end of the wall surface 11a to the vicinity of the bottom surface 11c.

[0026] The pressing plate 22 is a member that presses the tube 6 fitted in the groove 11 against the outer wall surface 11 b by the elastic force of a compression spring 24 .

[0027] The upper end of the pressing plate 22 is connected to a rotating shaft 23, and is capable of rotating in the width direction of the groove 11 around the rotating shaft 23. This allows the height of the protrusion 3 from the wall surface 11a to be variable.

[0028] 2 to 4, the pressing plate 22 is formed in a shape that allows it to contact the apex of a plurality of types of tubes 6 having different outer diameters on the wall surface 11a side and press the tubes perpendicularly against the wall surface 11b. Specifically, the pressing plate 22 is formed so that the cross-sectional shape along the width direction of the groove 11 is a parabola that is convex toward the outer wall surface 11b side.

[0029] Since the pressing plate 22 is formed in the shape described above, it has a portion that is farther away from the wall surface 11a the closer it is to the bottom surface 11c of the groove 11. Due to this shape, when the tube 6 is fitted into the groove 11, the pressing plate 22 is pressed by the tube 6 and rotates toward the wall surface 11a, as shown in Fig. 5, while guiding the tube 6 into the groove 11. In other words, a part of the pressing plate 22 functions as a guiding portion that guides the tube 6 into the groove 11 when the tube 6 is fitted into the groove 11.

[0030] The rotating shaft 23 supports the pressing plate 22 so that the pressing plate 22 can rotate in the width direction of the groove 11. The rotating shaft 23 is attached to the upper end of the base plate 21.

[0031] The compression spring 24 applies an elastic force to the pressing plate 22 for pressing the tube 6 fitted in the groove 11 against the wall surface 11b. One end of the compression spring 24 is connected to the base plate 21, and the other end is connected to the pressing plate 22.

[0032] Next, the function of the forming jig 1 will be described.

[0033] When the tube 6 is manufactured by bending using the forming jig 1, the tube 6 is fitted into the groove 11 by an operator so that the tube 6 is in contact with the bottom surface 11c over the entire length of the groove 11.

[0034] 5, the tube 6 is guided into the groove 11 by the pressing plate 22 at the protrusion 3. Therefore, even if the protrusion 3 is provided, the tube 6 is prevented from getting caught on the protrusion 3 and interfering with the work of fitting the tube 6 into the groove 11.

[0035] 2 to 4, when the tube 6 is fitted in the groove 11, the pressing plate 22 contacts the vicinity of the apex of the tube 6 on the wall surface 11a side, and presses the tube 6 perpendicularly against the wall surface 11b by the elastic force of the compression spring 24. As a result, the tube 6 is fixed in the groove 11.

[0036] The protrusion 3 presses the tube 6 against the wall surface 11b within a predetermined range including the change point P1 and a predetermined range including the change point P2, so that the tube 6 is fitted into the groove 11 so as to follow the wall surface 11b over the entire length of the groove 11.

[0037] FIG. 6 shows an example of a state in which a tube 6 is fitted into a forming jig that does not have protrusions 3, which is different from the present embodiment.

[0038] The forming jig 100 shown in Fig. 6 is obtained by omitting the two protrusions 3 from the forming jig 1 in Fig. 1. Here, even in the forming jig 100, the groove 11 is formed with a width wider than the design value of the outer diameter of the tube 6, taking into consideration the tolerance of the outer diameter of the tube 6 to be bent and the mountability of the tube 6.

[0039] When the tube 6 is fitted into the forming jig 100, there is a gap between the tube 6 and the wall surfaces 11a and 11b of the groove 11, and the tube 6 tries to maintain a straight shape due to its elasticity, even at the curved portion 16. As a result, the tube 6 does not bend according to the shape of the groove 11, and the contact angle with the wall surface 11b at the curved portion 16 becomes smaller than expected, which may cause the tube 6 to flatten locally. When the tube 6 flattens and loses elasticity, there may be places where the tube 6 buckles, as shown by the dashed circle in FIG. 6.

[0040] In contrast, in the forming jig 1 of this embodiment, as described above, within a specified range including the change point P1 and within a specified range including the change point P2, the protrusion 3 presses the tube 6 against the wall surface 11b, thereby preventing the tube 6 from buckling and fitting the tube 6 into the groove 11 so as to fit along the wall surface 11b.

[0041] However, even if the forming jig 1 has the protrusions 3, if they are disposed outside the above-mentioned predetermined ranges for each of the change points P1 and P2, buckling of the tube 6 may occur.

[0042] For example, as shown in Fig. 7, if the protrusion 3 corresponding to the change point P1 is disposed outside the predetermined range on the curved portion 16 side of the change point P1, buckling of the tube 6 may occur, as in the example of Fig. 6. Here, the predetermined range in which the protrusion 3 corresponding to the change point P1 is disposed is a range in which the central angle at the curvature center C of the curved portion 16 is equal to or smaller than a predetermined angle α on both sides of the change point P1. The same is true for the predetermined range in which the protrusion 3 corresponding to the change point P2 is disposed. The predetermined angle α is an angle that defines the range of the positions of the protrusions 3 that can prevent buckling of the tube 6, and is set in advance in the forming jig 1 based on experiments, etc.

[0043] Therefore, as described above, the protrusions 3 are disposed within a predetermined range including the change point P1 and within a predetermined range including the change point P2.

[0044] Once the tube 6 is fitted into the groove 11 of the forming jig 1, the forming jig 1 is heated, for example, to 70 to 120°C by a heating device (not shown), and then cooled. As a result, the tube 6 held by the forming jig 1 in a desired bent shape is heated and cooled, producing a bent tube 6. The forming jig 1 with the tube 6 fitted into the groove 11 may be heated in a furnace.

[0045] As described above, the forming jig 1 includes the protrusions 3 arranged on the wall surface 11a on the inner side of the curve of the groove 11, within a predetermined range including the change point P1 and a predetermined range including the change point P2.

[0046] As a result, within a predetermined range including the change point P1 and a predetermined range including the change point P2, the protrusions 3 press the tube 6 against the wall surface 11b, suppressing buckling of the tube 6 and allowing the tube 6 to fit into the groove 11 so as to conform to the wall surface 11b. As a result, the tube 6 can be bent into a desired shape.

[0047] Furthermore, in the bending process using the forming jig 1, there is no need to insert a core rod having a shape that matches the bending shape into the tube 6 in order to prevent buckling of the tube 6. Therefore, the tube 6 is not damaged by inserting or removing the core rod. Also, an increase in the work time required for bending the tube 6 due to the work of inserting or removing the core rod is suppressed.

[0048] Therefore, the forming jig 1 makes it possible to bend the tube 6 into a desired shape while suppressing an increase in working time and damage to the tube 6.

[0049] Furthermore, according to the forming jig 1, the radius of curvature that can be bent can be made smaller than in the case where there is no protrusion 3, and the degree of freedom in the bent shape can be increased.

[0050] In addition, in the forming jig 1, the height of the protrusions 3 from the wall surface 11a is variable, so it is possible to bend tubes 6 with various outer diameters without replacing the protrusions 3. It is also possible to accommodate variations in the outer diameter of the tube 6 due to differences in lots.

[0051] Furthermore, in the forming jig 1, the pressing plate 22 of the protrusion 3 guides the tube 6 into the groove 11 when the tube 6 is fitted into the groove 11. This improves the workability of fitting the tube 6 into the groove 11.

[0052] In the above-described embodiment, the protrusions 3 are provided only at the positions corresponding to the transition points P1 and P2, but additional protrusions 3 may be provided at other positions. For example, as shown in Fig. 8, the protrusions 3 may be provided on the wall surface 11a on the inside of the bend, near the midpoint of the curved portion 16. This makes it possible to further suppress buckling of the tube 6 and fit the tube 6 into the groove 11 so as to fit along the wall surface 11b with higher accuracy.

[0053] In the above embodiment, the height of the protrusion 3 is variable by the expansion and contraction of the compression spring 24. However, the height of the protrusion 3 may be variable by another elastic member.

[0054] The protrusion may have a fixed height. In this case, the height of the protrusion is set to a height that does not cause the tube 6 to be crushed and buckled. A protrusion with a fixed height may have a surface (guiding portion) that is formed to be farther away from the wall surface 11a on which the protrusion is installed toward the bottom surface 11c of the groove 11 and guides the tube 6 into the groove 11 when the tube 6 is fitted into the groove.

[0055] In the above embodiment, the pressing plate 22 has a parabolic cross section along the width direction of the groove 11, but this is not limiting. For example, the pressing plate may be a flat plate parallel to the wall surface 11a, and may press the tube 6 perpendicularly against the wall surface 11b by the elastic force of a compression spring.

[0056] FIG. 9 shows an example of a forming jig that can accommodate a bending shape different from the bending shape achieved by the forming jig 1 of FIG. 1 described in the above embodiment.

[0057] A forming jig 1A shown in FIG. 9 has the same configuration as the forming jig 1 in FIG. 1, except that the planar shape of the grooves 11 and the number and arrangement of the protrusions 3 are different.

[0058] The shape of the tube 6 bent using the forming jig 1A is an S-shape consisting of two continuous arc-shaped curved sections bending in opposite directions, a straight section connected to one of the curved sections, and a straight section connected to the other curved section.

[0059] According to this bending shape, groove 11 of forming jig 1A has two continuous arc-shaped curved portions 31, 32 that bend in opposite directions, a straight line portion 33 connected to curved portion 31, and a straight line portion 34 connected to curved portion 32. Groove 11 also includes change points P11 to P13 in its shape. Change point P11 is the boundary point between curved portion 31 and straight line portion 33. Change point P12 is the boundary point between curved portion 31 and curved portion 32. Change point P13 is the boundary point between curved portion 32 and straight line portion 34.

[0060] In the forming jig 1A, the protrusion 3 corresponding to the change point P11 is disposed on the inner wall surface 11a of the bend of the groove 11 at the change point P11 within a predetermined range including the change point P11. Also, the protrusion 3 corresponding to the change point P13 is disposed on the inner wall surface 11b of the bend of the groove 11 at the change point P13 within a predetermined range including the change point P13. In the example of FIG. 9, the protrusions 3 are disposed at the positions of the change points P11 and P12, respectively.

[0061] At the change point P12, protrusions 3 are disposed on the inner wall surface 11a of the curved portion 31 and on the inner wall surface 11b of the curved portion 32, respectively.

[0062] One of the protrusions 3 corresponding to the change point P12 is disposed on the wall surface 11a within a predetermined range including the change point P12 on the wall surface 11a on the inside of the bend of the curved portion 31. Here, the predetermined range including the change point P12 on the wall surface 11a is a range in which the central angle at the center of curvature Ca of the curved portion 31 is equal to or smaller than a predetermined angle on the curved portion 31 side from the change point P12.

[0063] The other protrusion 3 corresponding to the change point P12 is disposed on the wall surface 11b within a predetermined range including the change point P12 on the wall surface 11b on the inside of the bend of the curved portion 32. Here, the predetermined range including the change point P12 on the wall surface 11b is a range in which the central angle at the center of curvature Cb of the curved portion 32 is equal to or smaller than a predetermined angle on the curved portion 32 side from the change point P12.

[0064] The protrusion 3 on the curved portion 31 side and the protrusion 3 on the curved portion 32 side are positioned offset in opposite directions from each other with respect to the change point P12 within the above-mentioned corresponding specified ranges in order to prevent the tube 6 from being crushed.

[0065] Here, in the forming jig 100A shown in FIG. 10, which has a configuration in which the protrusions 3 of the forming jig 1A in FIG. 9 are omitted, there may be locations where the tube 6 buckles, similar to the forming jig 100 in FIG. 6 described above.

[0066] In contrast, in the forming jig 1A of Figure 9, by arranging the protrusions 3 as described above, buckling of the tube 6 is suppressed, and the tube 6 can be fitted into the groove 11 so that it follows the wall surface 11b at the curved portion 31 and the straight portion 33, and follows the wall surface 11a at the curved portion 32 and the straight portion 34.

[0067] Next, an example of a forming jig that can be used to process other bending shapes is shown in FIG.

[0068] The forming jig 1B shown in FIG. 11 has the same configuration as the forming jig 1 in FIG. 1, except that the planar shape of the grooves 11 and the number of protrusions 3 are different.

[0069] The shape of the tube 6 bent by the forming jig 1B is an L-shape consisting of a quarter-arc curved portion and two straight portions connected to one end and the other end of the curved portion. In accordance with this bending shape, the groove 11 of the forming jig 1B has a quarter-arc curved portion 41, a straight line portion 42 connected to one end of the curved portion 41, and a straight line portion 43 connected to the other end of the curved portion 16. The groove 11 also includes change points P21 and P22 in its shape. The change point P21 is the boundary point between the curved portion 41 and the straight line portion 42. The change point P22 is the boundary point between the curved portion 41 and the straight line portion 43.

[0070] In the forming jig 1B, the protrusions 3 are provided on the wall surface 11a on the inner side of the curve of the groove 11 within a predetermined range including the change point P21 and a predetermined range including the change point P22. In the example of Fig. 11, the protrusions 3 are provided at the positions of the change points P21 and P22, respectively.

[0071] Here, in the forming jig 100B shown in FIG. 12, which has a configuration in which the protrusions 3 of the forming jig 1B in FIG. 11 are omitted, there may be locations where the tube 6 buckles, similar to the forming jig 100 in FIG. 6 described above.

[0072] In contrast, in the forming jig 1B of FIG. 11, by arranging the protrusions 3 as described above, buckling of the tube 6 is suppressed, and the tube 6 can be fitted into the groove 11 so as to fit along the wall surface 11b.

[0073] In the forming jigs 1, 1A, and 1B shown in Figures 1, 9, and 11, respectively, protrusions 3 are arranged corresponding to all of the change points in the shape of the groove 11. However, unlike the examples in Figures 1, 9, and 11, if the groove 11 has a shape such that buckling of the tube 6 does not occur even if protrusions 3 corresponding to some of the change points are omitted, the protrusions 3 corresponding to those change points can be omitted.

[0074] The present invention is not limited to the above-described embodiment, and the components can be modified and embodied in the implementation stage without departing from the gist of the invention. In addition, various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiment. For example, some components may be deleted from all the components shown in the embodiment.

[0075] [Note] This application discloses the following inventions.

[0076] (Appendix 1) a groove formed into a shape corresponding to a bending shape of the tube and into which the tube is fitted; a protrusion portion disposed on the inner wall surface of the bend of the groove within a predetermined range including a change point of the shape of the groove; A forming jig comprising:

[0077] (Appendix 2) The forming jig described in Appendix 1, wherein the protrusion has a variable height from the inner wall surface.

[0078] (Appendix 3) The forming jig described in Appendix 1 or 2, characterized in that the protrusion portion is formed so as to move away from the inner wall surface as it approaches the bottom surface of the groove, and has a guide portion that guides the tube into the groove when the tube is inserted into the groove.

[0079] (Appendix 4) A tube produced using the forming jig described in any one of claims 1 to 3. [Explanation of symbols]

[0080] 1,1A,1B,100,100A,100B forming jig 2 Jig body 3 Protrusion 6 Tubes 11 Groove 11a, 11b Wall 11c Bottom 16,31,32,41 Curve section 17,18,33,34,42,43 Straight section 21 Base plate 22 Pressing plate 23 Rotating shaft 24 Compression spring P1, P2, P11~P13, P21, P22 change points

Claims

1. a groove formed into a shape corresponding to a bending shape of the tube and into which the tube is fitted; a protrusion portion disposed on the inner wall surface of the bend of the groove within a predetermined range including a change point of the shape of the groove; A forming jig comprising:

2. The forming jig according to claim 1 , wherein the height of the protrusion from the inner wall surface is variable.

3. The forming jig according to claim 1 or 2, characterized in that the protrusion portion is formed so as to move away from the inner wall surface as it approaches the bottom surface of the groove, and has a guide portion that guides the tube into the groove when the tube is inserted into the groove.

4. A tube produced by using the forming jig according to claim 1 or 2.

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