JP-2026074581-A - Bending fatigue testing apparatus for string-like members

JP2026074581AJP 2026074581 AJP2026074581 AJP 2026074581AJP-2026074581-A

Abstract

[Problem] To provide a technology that can suppress friction of string-like members. [Solution] The bending fatigue testing apparatus 10 for a string-like member SB according to the present disclosure comprises a cylindrical jig 1 that clamps 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. [Selection Diagram] Figure 1

Inventors

高坂博宣
中野泰良
西森宏樹

Assignees

トヨタ自動車株式会社

Dates

Publication Date: 20260507
Application Date: 20241021

Claims (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 cylindrical jig is further comprising a rotating mechanism that rotatably holds the cylindrical jig, a textured surface provided on the outer surface of the cylindrical jig, a groove provided on the outer surface of the cylindrical jig, and at least one film covering the outer surface of the cylindrical jig. A bending fatigue testing apparatus for string-like members.

Description

This disclosure relates to a bending fatigue testing apparatus for string-like members. The cable bending jig disclosed in Patent Document 1 is formed to be flexible, extends along the longitudinal direction of the cable, and includes a pair of clamping parts for gripping the cable from both sides. This cable bending jig is suitable for bending tests that involve bending the cable multiple times or bending it in the opposite direction. Japanese Patent Publication No. 2013-005686 This is a schematic diagram showing one example of the configuration of a bending fatigue testing apparatus according to Embodiment 1.This is a top view showing one example of the configuration of a cylindrical jig according to Embodiment 1.This is a front view showing another configuration example of the cylindrical jig according to Embodiment 1. The following describes specific embodiments of the present invention in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Furthermore, for clarity, the following description and drawings have been simplified as appropriate. <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. It should be noted that the right-handed XYZ coordinate system shown in Figure 1 and other drawings is merely a convenient representation for explaining the positional relationships of the components. Typically, the positive Z-axis is vertically upward, and the XY plane is horizontal; this is consistent across all drawings. As shown in Figure 1, the bending fatigue testing apparatus 10 comprises cylindrical jigs 1 and 2, and a rotating mechanism 3. As shown in Figures 1 and 2, the cylindrical jig 1 comprises a body 1A and a groove 1b. The 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, which is the object of fatigue testing in the bending fatigue testing apparatus 10. The groove 1b is provided on the outer circumferential surface 1a of the body 1A. In this embodiment, the groove 1b extends along the axial direction (here, the Y-axis direction) of the body 1A. In this embodiment, multiple grooves 1b are arranged on the outer circumferential surface 1a at predetermined intervals in the outer circumferential direction of the body 1A. The cylindrical jig 2 has the same configuration as the cylindrical jig 1. At least one of the cylindrical jig 1 and the cylindrical jig 2 is preferably held so as to be close to the other so that the string-like member SB can be clamped. The bending fatigue testing apparatus 10 may further include a moving mechanism for moving at least one of the cylindrical jig 1 and the cylindrical jig 2. 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. Here, we will explain the bending fatigue testing method for a string-like member using the bending fatigue testing apparatus 10. The string-like member SB is sandwiched between cylindrical jigs 1 and 2. The cylindrical jigs 1 and 2 hold the string-like member SB. Since the radii of cylindrical jigs 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. Next, the ends of the string-like member SB are moved back and forth vertically. It is preferable to move the ends of the cylindrical jigs 1 and 2, or the ends of the string-like member SB, back and forth vertically. This generates compressive and tensile stress in the string-like member SB. Therefore, when the number of reciprocating motions reaches a certain value, the string-like member SB will suffer bending damage. The bending fatigue limit of the string-like member SB can be evaluated from the number of reciprocating motions and the degree of damage. Here, the cylindrical jigs 1 and 2 rotate in response to the reciprocating motion of the string-like member SB. Therefore, the frictional resistance between the string-like member SB and the cylindrical jigs 1 and 2 is reduced. Furthermore, the groove 1b is provided on the outer circumferential surface 1a of the main body 1A of the cylindrical jigs 1 and 2. Therefore, the contact area between the string-like member SB and the cylindrical jigs 1 and 2 is small. Consequently, the frictional resistance between the string-like member SB and the cylindrical