Core metal jig

Abstract

To provide a core metal jig of a novel structure capable of bending a workpiece in its longitudinal direction while suppressing deformation of the cross-sectional shape, and having excellent manufacturability. [Solution] A core bar jig 20 is set in a recess 15 of a workpiece 1 having a predetermined cross-sectional shape, and suppresses deformation when the workpiece 1 is curved in its longitudinal direction. The core bar jig 20 includes a resin core bar body 21 extending in a rod shape and having a pair of side surfaces 22, 23 and a bottom surface 25 facing respectively to a pair of side walls 16, 17 and a bottom wall 18 constituting the recess 15 of the workpiece 1, and a metal end member 40 having a pair of side surfaces 42, 43 and a bottom surface 46 facing respectively to the pair of side walls 16, 17 and the bottom wall 18, and connected to the base end side end of the core bar body 21 so as to be rotatable relative to the curved direction of the workpiece 1.

Description

[Technical field]

[0001] This invention relates to a core bar jig used for bending a workpiece having a predetermined cross-sectional shape in its longitudinal direction. [Background technology]

[0002] For example, a roll-formed body having a predetermined cross-sectional shape and curved in the longitudinal direction is used as a rail guide for an automobile. The roll molded body has a concave cross-sectional shape due to bending of both ends in the width direction, but during bending to curve the roll in the longitudinal direction, the wall of the roll molded body that defines the concave cross-sectional shape collapses, and the cross-sectional shape of the roll molded body is easily deformed. As a means for suppressing such deformation during bending, a core metal jig is used that is inserted into the recess of the roll molded body to prevent the wall from collapsing.

[0003] Conventionally, a core metal jig used in bending processing has been made by stacking multiple plates of spring steel and welding them together. However, its manufacture requires heat treatment and welding of the plates, which requires time, cost, and skill, and therefore improvements have been desired from the viewpoint of improving the manufacturability of the core metal jig. The following patent document describes related technology. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-27880 A Summary of the Invention [Problem to be solved by the invention]

[0005] This invention has been made in light of the above circumstances and aims to provide a core wire jig of a new structure that is capable of curving the workpiece in its longitudinal direction while suppressing deformation of the cross-sectional shape of the workpiece, and that is also easy to manufacture. [Means for solving the problem]

[0006] The core metal jig according to the first aspect of the present invention is defined as follows: A core metal jig that is set in a recess of a workpiece having a predetermined cross-sectional shape and suppresses deformation of the workpiece when the workpiece is curved in a longitudinal direction thereof, a resin core bar body extending in a rod shape and having a pair of side surfaces and a bottom surface facing a pair of side walls and a bottom wall, respectively, that define a recess in the workpiece; a metal end member having a pair of side surfaces and a bottom surface facing the pair of side walls and the bottom wall, respectively, and connected to a base end side end of the core body so as to be relatively rotatable in the bending direction; It is equipped with:

[0007] According to the core bar jig defined in this way, the resin core bar body and the metal end members that constitute the core bar jig can be produced by machining, and processes such as heat treatment and welding of plate materials are not required, making it easier to manufacture than the conventional core bar jig made of spring steel. The core wire jig of the present invention has a pair of side and bottom surfaces that face the pair of side walls and bottom walls that form the recess of the workpiece, and can prevent the side walls and bottom walls of the workpiece from collapsing during bending, thereby maintaining the cross-sectional shape of the workpiece. The end of the workpiece, which is subjected to particularly high processing force during bending, is configured to be abutted by a high-strength metal end member, thereby avoiding problems such as local deformation and crushing due to insufficient strength of the core wire. In addition, when the resin core wire body and the metal end member are bent while connected, the strain stress generated at the connection part due to the difference in the amount of deformation can be alleviated by the relative rotation of the end member.

[0008] Here, the core bar jig of the present invention can connect the core bar body and the end member by using a bolt having a shaft portion, a male thread portion formed on the tip side of the shaft portion, and a flange portion provided on the base end side of the shaft portion and having a larger diameter than the shaft portion. In this case, the core bar body sandwiched between the flange portion and the end member can be configured to be rotatably held around the shaft portion when the bolt is screwed into the female threaded hole of the end member (second aspect).

[0009] Furthermore, the core bar jig of the present invention can be configured to have rubber contact members that protrude from a pair of side surfaces of the core bar body and come into contact with the workpiece (third aspect). In this way, problems such as the core wire jig unintentionally shifting out of position due to vibrations during bending and falling out of the recess in the workpiece can be avoided by the abutment action between the abutment member and the workpiece.

[0010] Furthermore, the core metal jig of the present invention can form a step portion on the side surface of the end member that can come into contact with the end face of the workpiece (fourth aspect). In this way, by bringing the end face of the workpiece into contact with the step portion of the end member, the core metal jig can be easily positioned at a predetermined bending position.

[0011] Furthermore, in the core bar jig of the present invention, the end portion on the tip side of the core bar body can be formed into a tapered shape in which the dimension between the side surfaces becomes smaller toward the tip (a fifth aspect). In this way, it is possible to avoid the occurrence of a problem in which the tip of the core metal jig deformed during bending comes into localized contact with the workpiece, causing deformation of that portion. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing an example of a workpiece to be bent, in which (A) is a side view and (B) is a cross-sectional view thereof. [Diagram 2] 1A and 1B are diagrams showing the configuration of a core wire jig according to one embodiment of the present invention, in which (A) is a plan view and (B) is a side view with a portion cut away. [Diagram 3] FIG. 3 is a perspective view of the core metal jig of FIG. 2. [Figure 4] FIG. 2 is an explanatory diagram of bending of a workpiece. [Diagram 5] FIG. 5 is an explanatory diagram of the bending process of the workpiece following FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram showing an example of a workpiece to be bent. The workpiece 1 is a rod-shaped member that extends linearly with a predetermined cross-sectional shape, and is cut to a predetermined length. The material of the workpiece 1 is not particularly limited, but may be an iron-based material such as steel, an aluminum-based material, or the like. The workpiece 1 is obtained by roll-forming a long strip-shaped metal plate pulled out from an uncoiler (not shown), and its cross-sectional shape is hollow, as shown in the same figure (B), with a first wall portion 11 and a second wall portion 12 extending upward in the figure, a third wall portion 13 connecting one end side of the first wall portion 11 and the second wall portion 12 to each other, and a fourth wall portion 14 bent inwardly and parallel to the third wall portion 13 at the other end side of the second wall portion 12.

[0014] FIG. 1(A) shows a side view of a portion (one end side) of the workpiece 1 in the longitudinal direction. The workpiece 1 shown in FIG. 1 is then bent at one end with a substantially constant curvature (radius of curvature R) along the longitudinal direction using a bending machine. In FIG. 1A, the shape after bending is shown by a two-dot chain line. A core bar jig 20 according to an embodiment of the present invention is used to prevent the collapse of the cross-sectional shape that occurs during such bending (more specifically, the collapse of the fourth wall portion 14 in FIG. 1B, which narrows the width dimension W0).

[0015] Next, a core bar jig 20 according to an embodiment of the present invention will be described. The core metal jig 20 of this embodiment is a member that is set in a recess 15 defined by the third wall 13, the second wall 12, and the fourth wall 14 of the workpiece 1 shown in Fig. 1, and suppresses deformation of the cross-sectional shape that occurs during bending. The specific shape of the core metal jig 20 is shown in Figs. 2 and 3.

[0016] The core metal jig 20 includes a resin core metal body 21, a metal end member 40, and a bolt 35 as a connecting member that connects these together. Core bar body 21 is a columnar member extending straight in the longitudinal direction, and has side surfaces 22, 23, a surface 24, and a bottom surface 25. The dimension W1 between the side surfaces of core bar body 21 is the same as or slightly smaller than the width dimension W0 (see FIG. 1) of recess 15 in workpiece 1, and the thickness dimension T1 of core bar body 21 is the same as or slightly larger than the depth dimension T0 (see FIG. 1) of recess 15 in workpiece 1.

[0017] When set in the recess 15, the side surfaces 22, 23 face the pair of side walls 16, 17 (third wall 13, fourth wall 14) that constitute the recess 15 of the workpiece 1, and the bottom surface 25 faces the bottom wall 18 (second wall 12) that constitutes the recess 15 (see FIG. 4(B)). During bending, the pair of side walls 16, 17 and bottom wall 18 that define the recess 15 are restrained, preventing the side walls 16, 17 and bottom wall 18 from collapsing. 2(A) suppresses the collapse of the side walls 16, 17 and the bottom wall 18 that are set in the recess 15, and the length L is set to be longer than the length of the portion of the workpiece 1 to be bent. The end of the core bar body 21 on the tip side (right side in the figure) of the region of length L has a tapered shape in which the dimension between the side surfaces (in the width direction) becomes smaller toward the tip.

[0018] The core metal body 21 plays a role in bending the workpiece 1 at a predetermined curvature while maintaining a predetermined cross-sectional shape during bending. For this reason, it is preferable to use a resin that is easy to machine and has predetermined strength characteristics as the material for the core metal body 21. In more detail, examples of the material include MC nylon and POM (Duracon) with a tensile strength of 50 to 100 MPa and a bending strength of 80 to 110 MPa.

[0019] 2(A), at a portion of the core bar body 21 having a width dimension W1, rubber abutment members 28 are provided at two locations spaced apart in the longitudinal direction so as to partially protrude from the side surfaces 22, 23. This is to prevent problems such as the core bar jig 20 set in the recess 15 unintentionally coming out of the recess 15 due to vibrations or the like during bending. An example of the material for the abutment members 28 is fluororubber having a Shore A hardness of about 60 to 80.

[0020] The base end side (left side in the figure) of the core metal body 21 is a connecting portion 30 that is connected to the end member 40. As shown in Fig. 2(B), the connecting portion 30 is machined to a thin portion that is approximately half the thickness of other portions of the core metal body 21, and is provided with a through hole 31 for inserting a connecting bolt 35 therethrough.

[0021] The end member 40 is a member connected to the base end side of the core bar body 21, and is made of a metal (for example, general structural steel SS400) having strength higher than that of the core bar body 21. As shown in FIG. 2(B), the end member 40 includes a thick engagement portion 41 and a thin connection portion 48. End member 40 has sides 42, 43, a surface 45 and a bottom surface 46, and the side-to-side dimension of end member 40 is the same as the side-to-side dimension W1 of core bar body 21, and the thickness dimension of engagement portion 41 is the same as the thickness dimension T1 of core bar body 21.

[0022] As shown in Fig. 2(A), a step portion 44 is formed on the side surfaces 42, 43 of the engagement portion 41, and the end face 1a (see Fig. 1(A)) of the workpiece 1 can abut against the step portion 44. When the core metal jig 20 is set in the recess 15 of the workpiece 1, the end member 40 restrains the end portion (the end portion near the end face 1a) of the workpiece 1 from the inside (see Fig. 4).

[0023] The connecting portion 48 is a portion that is connected to the core bar body 21 via the bolt 35, and is overlapped with the connecting portion 30 of the core bar body 21 in the thickness direction. As shown in Fig. 2(B) , the connecting portion 48 is machined to be thin-walled so that a surface 45 and a bottom surface 46 of the end member 40 are substantially flush with the surface 24 and the bottom surface 25 of the core bar body 21 when overlapped with the connecting portion 30 of the core bar body 21. A female screw hole 49 that screws into the connecting bolt 35 is formed in this connecting portion 48.

[0024] The connecting bolt 35 has a shaft portion 36, a male thread portion 37 formed on the tip side of the shaft portion 36, and a flange portion 38 provided on the base end side of the shaft portion 36 and having a larger diameter than the shaft portion 36. In this embodiment, a bolt 35 is inserted into the through hole 31 of the core body 21, and the male threaded portion 37 of the bolt 35 is screwed into the female threaded hole 49 on the end member 40 side so that the flange portion 38 of the bolt 35 and the connecting portion 48 on the end member 40 side sandwich the connecting portion 30 of the core body 21. As shown by the dotted line in Figure 2 (A), the end member 40 is capable of rotating relative to the core body 21 in the curved direction.

[0025] Next, bending of the workpiece 1 performed using the core metal jig 20 will be described with reference to FIGS. First, as shown in Fig. 4, a core metal jig 20 is set in a recess 15 of a workpiece 1 having a predetermined cross-sectional shape. At this time, the end face 1a of the workpiece 1 is brought into contact with a step portion 44 of the core metal jig 20, whereby the core metal jig 20 is set in a predetermined position.

[0026] Thereafter, the workpiece 1 is curved in its longitudinal direction using a bending device. The bending method is not particularly limited, and known bending methods such as press bending, roll rotary bending, and rotary draw bending can be used. For example, as shown in FIG. 5, a bending device 50 including a bending die 51 having a processing surface 51a with a predetermined curvature radius, a vice 52 for clamping the end of the workpiece 1, and a pressing die 53 for pressing the workpiece 1 against the bending die 51 is used, and the bending die 51 is rotated while the pressing die 53 is pressing the straight tube portion (unprocessed portion) of the workpiece 1 against the processing surface 51a of the bending die 51 in sequence, and the end of the workpiece 1 is deformed so as to be wrapped around the bending die 51, thereby obtaining a workpiece 1 whose end is curved in the longitudinal direction with a predetermined bend R. Furthermore, the core wire jig 20 that has been bent together with the workpiece 1 can be removed from the recess 15 by pushing it out in a direction perpendicular to the plane of the paper in Figure 5, and it will return to its original straight shape from its previous elastically deformed state curved in the longitudinal direction.

[0027] As described above, the core metal jig 20 of this embodiment has a pair of side surfaces (side surfaces 22, 23 of the core metal body 21 and side surfaces 42, 43 of the end member 40) and a bottom surface (bottom surface 25 of the core metal body 21 and bottom surface 46 of the end member 40) that face the pair of side walls 16, 17 and bottom wall 18 that constitute the recess 15 of the workpiece 1, respectively, and can prevent the side walls 17 and bottom wall 18 of the workpiece 1 from collapsing during bending, thereby maintaining the cross-sectional shape of the workpiece 1. The end portion of the workpiece 1 to which a particularly high processing force is applied during bending is configured to be abutted by the end member 40 made of metal with high strength, and problems such as local deformation and crushing due to insufficient strength of the core metal can be avoided. In addition, when the resin core metal body 21 and the metal end member 40 are bent in a connected state, the strain stress generated at the connection portion based on the difference in the amount of deformation can be alleviated by the relative rotation of the end member 40.

[0028] In addition, in the core wire jig 20 of this embodiment, with the bolt 35 as a connecting member screwed into the female threaded hole 49 of the end member 40, the core wire body 21 sandwiched between the flange portion 38 and the end member 40 is held rotatably around the shaft portion 36, and the metal end member 40 is rotated relatively in the curving direction of the workpiece 1 during bending, thereby relieving the distortion stress generated in the connecting portion.

[0029] In addition, the core wire jig 20 of this embodiment is provided with a rubber abutment member 28 that protrudes from a pair of side surfaces 22, 23 and abuts against the workpiece 1, and the abutment action between the abutment member 28 and the workpiece 1 can avoid problems such as the core wire jig 20 unintentionally shifting out of position due to vibrations during bending processing, and falling out of the recess 15 of the workpiece 1.

[0030] In addition, in the core wire jig 20 of this embodiment, a step portion 44 that can abut against the end face 1a of the workpiece 1 is formed on the side surfaces 42, 43 of the end member 40, and by abutting the end face 1a of the workpiece 1 against the step portion 44 of the end member 40, the core wire jig 20 can be easily positioned at a predetermined bending position in the workpiece 1.

[0031] Furthermore, in the core wire jig 20 of this embodiment, the end portion on the tip side of the core wire body 21 has a tapered shape in which the dimension between the side surfaces becomes smaller toward the tip, thereby preventing the tip of the core wire jig 20 that has been deformed during bending from coming into localized contact with the workpiece 1, thereby preventing the occurrence of defects in which that portion is deformed.

[0032] Although the embodiment of the present invention has been described above in detail, this is merely an example. The side-to-side dimension, thickness dimension, and length dimension of the core metal jig in the above embodiment can be appropriately changed according to the shape of the recess of the workpiece on which the core metal jig is set. In addition, although the above embodiment is an example in which the core metal jig is applied to bending the workpiece made of a roll molded body, the core metal jig of the present invention can also be applied to workpieces other than roll molded bodies, and the present invention can be embodied in various modified forms within the scope of its purpose. [Explanation of symbols]

[0033] 1 Work material 1a End face 15 Recess 16,17 side wall 18 Bottom wall 20 Core metal jig 21 Core body 22,23 Side 25 Bottom 28 Contact member 35 Volts 36 Shaft 37 Male thread 38 Flange 40 End members 42,43 Side 44 Step 46 Bottom 49 Female thread hole W1 Side-to-side dimension (width dimension)

Claims

1. A core metal jig that is set in a recess of a workpiece having a predetermined cross-sectional shape and suppresses deformation of the workpiece when the workpiece is curved in a longitudinal direction thereof, a resin core bar body extending in a rod shape and having a pair of side surfaces and a bottom surface facing a pair of side walls and a bottom wall, respectively, that define a recess in the workpiece; a metal end member having a pair of side surfaces and a bottom surface facing the pair of side walls and the bottom wall, respectively, and connected to a base end side end of the core body so as to be relatively rotatable in the bending direction; The core wire jig is provided with:

2. A core bar jig as described in claim 1, which uses a bolt having a shaft portion, a male threaded portion formed on the tip side of the shaft portion, and a flange portion provided on the base end side of the shaft portion and having a larger diameter than the shaft portion, and when the bolt is screwed into the female threaded hole of the end member, the core bar body sandwiched between the flange portion and the end member is held rotatably around the shaft portion.

3. 2. The core bar jig according to claim 1, wherein the core bar body is provided with rubber contact members protruding from the pair of side surfaces and contacting the workpiece.

4. 2. The core metal jig according to claim 1, wherein a step portion capable of coming into contact with the end face of the workpiece is formed on a side surface of the end member.

5. 2. The core metal jig according to claim 1, wherein the end portion on the tip side of the core metal body is tapered so that the dimension between the side surfaces decreases toward the tip.

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