Bending fatigue testing apparatus for string-like members

Abstract

This invention provides a technology that can suppress friction in string-like components. [Solution] The bending fatigue testing apparatus 10 for a string-like member SB according to the present disclosure comprises a cylindrical jig 1 that holds the string-like member SB so that the string-like member SB bends at the minimum bending radius. The bending fatigue testing apparatus 10 further comprises a rotating mechanism 3 that rotatably holds the cylindrical jig 1, a textured portion provided on the outer circumferential surface 1a of the cylindrical jig 1, a groove 1b provided on the outer circumferential surface 1a of the cylindrical jig 1, and at least one film 1c that covers the outer circumferential surface 1a of the cylindrical jig 1.

Description

Technical Field

[0001] The present disclosure relates to a bending fatigue test apparatus for a string-like member.

Background Art

[0002] The cable bending jig disclosed in Patent Document 1 is formed to be bendable, extends along the longitudinal direction of the cable, and includes a pair of clamping portions for clamping the cable from both sides. The cable bending jig is suitable for a bending test in which the cable is bent multiple times or bent in the opposite direction.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventors of the present application have discovered the following technical problems. There is a bending fatigue test in which a string-like member is bent multiple times or bent in the opposite direction. When performing a bending fatigue test using the above-described cable bending jig, a pair of clamping portions clamp the string-like member from both sides. Therefore, the string-like member is rubbed, and the bending fatigue test cannot be appropriately performed.

[0005] The present disclosure has been made in view of the above problems, and provides a technique capable of suppressing rubbing of a string-like member.

Means for Solving the Problems

[0006] The bending fatigue test apparatus for a string-like member according to the present disclosure includes a cylindrical jig that clamps the string-like member so that the string-like member bends at a minimum bending radius. The device further comprises a rotating mechanism that rotatably holds the cylindrical jig, a textured surface provided on the outer circumferential surface of the cylindrical jig, a groove provided on the outer circumferential surface of the cylindrical jig, and at least one film covering the outer circumferential surface of the cylindrical jig. [Effects of the Invention]

[0007] According to this disclosure, friction of the string-like member can be suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing one example of the configuration of a bending fatigue testing apparatus according to Embodiment 1. [Figure 2] This is a top view showing one example of the configuration of a cylindrical jig according to Embodiment 1. [Figure 3] This is a front view showing another configuration example of the cylindrical jig according to Embodiment 1. [Modes for carrying out the invention]

[0009] Specific embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings have been simplified as appropriate.

[0010] <Embodiment 1> Embodiment 1 will be described with reference to Figures 1 to 3. Figure 1 is a schematic diagram showing one example of the configuration of a bending fatigue testing apparatus according to Embodiment 1. Figure 2 is a top view showing one example of the configuration of a cylindrical jig according to Embodiment 1. Figure 3 is a front view showing another example of the configuration of a cylindrical jig according to Embodiment 1.

[0011] It should be noted that the right-handed XYZ coordinate system shown in Figure 1 and other drawings is merely for convenience in explaining the positional relationships of the components. Typically, the positive Z-axis is vertically upward, and the XY plane is horizontal, and this is consistent across drawings.

[0012] As shown in Figure 1, the bending fatigue testing apparatus 10 comprises cylindrical jigs 1 and 2 and a rotating mechanism 3.

[0013] As shown in Figures 1 and 2, the cylindrical jig 1 comprises a main body 1A and a groove 1b. The main body 1A is a substantially cylindrical body. The radius of this substantially cylindrical body is preferably the same as the minimum bending radius of the string-like member SB that is the subject of fatigue testing in the bending fatigue testing apparatus 10. The groove 1b is provided on the outer circumferential surface 1a of the main body 1A. In this embodiment, the groove 1b extends along the axial direction (here, the Y-axis direction) of the main body 1A. In this embodiment, a plurality of grooves 1b are arranged on the outer circumferential surface 1a at predetermined intervals in the outer circumferential direction of the main body 1A.

[0014] Cylindrical jig 2 has the same configuration as cylindrical jig 1. At least one of cylindrical jig 1 and cylindrical jig 2 is preferably held so as to be close to the other so that the string-like member SB can be gripped. The bending fatigue testing apparatus 10 may further include a moving mechanism for moving at least one of cylindrical jig 1 and cylindrical jig 2.

[0015] The rotation mechanism 3 holds the cylindrical jigs 1 and 2 so that they can rotate around axes Y1 and Y2 of the main body 1A, respectively. The rotation mechanism 3 may be equipped with a drive source to rotate the cylindrical jigs 1 and 2 clockwise or counterclockwise, as appropriate.

[0016] Here, we will describe a method for performing a bending fatigue test on a string-like member using a bending fatigue testing apparatus 10.

[0017] The string-like member SB is sandwiched between cylindrical jig 1 and cylindrical jig 2. Cylindrical jig 1 and cylindrical jig 2 hold the string-like member SB. Since the radii of cylindrical jig 1 and 2 are the same as the minimum bending radius of the string-like member SB, the string-like member SB bends at its minimum bending radius.

[0018] Subsequently, both ends of the string-shaped member SB are reciprocated in the vertical direction. It is preferable to reciprocate both ends of the cylindrical jigs 1 and 2 or both ends of the string-shaped member SB in the vertical direction. By doing so, compressive stress and tensile stress are generated in the string-shaped member SB. Therefore, when the number of reciprocations reaches a certain value, the string-shaped member SB is damaged by bending. From the number of reciprocations and the degree of damage, the bending fatigue limit of the string-shaped member SB can be evaluated.

[0019] Here, as the string-shaped member SB reciprocates, the cylindrical jigs 1 and 2 rotate. Therefore, the frictional resistance between the string-shaped member SB and the cylindrical jigs 1 and 2 is reduced.

[0020] Also, the groove 1b is provided on the outer peripheral surface 1a of the main body 1A of the cylindrical jigs 1 and 2. Therefore, the contact area between the string-shaped member SB and the cylindrical jigs 1 and 2 is small. Accordingly, the frictional resistance between the string-shaped member SB and the cylindrical jigs 1 and 2 is reduced. That is, rubbing of the string-shaped member SB can be suppressed.

[0021] Further, the bending fatigue test device 10 may include the cylindrical jig 11 shown in FIG. 3. The cylindrical jig 11 is another configuration example of the cylindrical jigs 1 and 2 shown in FIGS. 1 and 2. As shown in FIG. 3, the cylindrical jig 11 has the same configuration as the cylindrical jigs 1 and 2 except that it includes a film 1c. The film 1c covers the outer peripheral surface 1a of the cylindrical jig 11. The film 1c may be formed using, for example, a fluororesin coating. The frictional resistance between the film 1c and the string-shaped member SB is smaller than the frictional resistance between the outer peripheral surface 1a and the string-shaped member SB. That is, rubbing of the string-shaped member SB can be suppressed.

[0022] Also, the cylindrical jigs 1 and 2 may include a dimpled portion instead of the groove 1b. The dimpled portion is provided on the outer peripheral surface 1a of the cylindrical jigs 1 and 2. The dimpled portion has a smaller contact area with the string-shaped member SB compared to the outer peripheral surface 1a. That is, the contact area between the string-shaped member SB and the cylindrical jigs 1 and 2 is small. Accordingly, the frictional resistance between the string-shaped member SB and the cylindrical jigs 1 and 2 is reduced. That is, rubbing of the string-shaped member SB can be suppressed.

[0023] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. Furthermore, the present invention may be implemented by combining the above embodiments or examples thereof as appropriate. For example, the bending fatigue testing apparatus 10 may further include a rotating mechanism 3, a groove 1b, a film 1c, and at least one of the above-described textured parts. [Explanation of Symbols]

[0024] 10. Bending fatigue testing apparatus 1, 2. Cylindrical jig 1A Main Unit 1a Outer surface 1b Groove 1c membrane 3 Rotation mechanism SB string-like member Y1 and Y2 axes

Claims

[Claim 1] The device includes a cylindrical jig that holds the string-like member so that the string-like member bends with the minimum bending radius, The system further comprises a rotating mechanism that rotatably holds the cylindrical jig, a textured surface provided on the outer circumferential surface of the cylindrical jig, a groove provided on the outer circumferential surface of the cylindrical jig, and at least one film covering the outer circumferential surface of the cylindrical jig. A bending fatigue testing apparatus for string-like members.

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