Looseness indicator unit and attachment structure for looseness indicator unit

Abstract

The present invention can facilitate handling of a looseness indicator unit and an attachment structure of the looseness indicator unit. The looseness indicator unit 10 comprises first looseness indicators 11 and second looseness indicators 12. The first loosening indicators 11 and the second loosening indicators 12 are each configured such that, in a state in which the insertion force of a second fastening part 12A to a second nut N2 is smaller than the insertion force of a first fastening part 11A to a first nut N1, and the second fastening part 12A is fastened to the second nut N2 and the first fastening part 11A is fastened to the first nut N1, at least a portion of a second extension part 12B is positioned on a hub part WH side of a wheel disk with respect to a first extension part 11B so as to overlap the first extension part 11B.

Description

Looseness indicator unit and mounting structure for looseness indicator unit

[0001] The present disclosure relates to a looseness indicator unit and a mounting structure for a looseness indicator unit.

[0002] An example of a wheel nut lock includes a central body, and a first extension portion and a second extension portion each extending from the central body. The central body includes a toothed hole penetrating the central body along a central axis of the central body, and the toothed hole is defined by a plurality of raised portions extending along the central axis. In the wheel nut lock, the central body is attached to a wheel nut. The first extension portion includes an indicator and a latch.

[0003] For the plurality of wheel nuts arranged along the circumferential direction of the wheel, one wheel nut lock is attached to one wheel nut. At this time, in the first wheel nut lock and the second wheel nut lock adjacent to each other in the circumferential direction, the latch of the first wheel nut lock engages with the second extension portion of the second wheel nut lock. Thereby, the indicator of the first wheel nut is covered by the second extension portion of the second wheel nut. When the rotation amount of the first wheel nut lock relative to the second wheel nut lock exceeds a predetermined value, the latch of the first wheel nut lock disengages from the second extension portion of the second wheel nut lock, whereby the indicator of the first wheel nut lock is exposed. (see, for example, Patent Document 1).

[0004] International Publication No. 2013 / 049913

[0005] Incidentally, the raised portions defining the toothed hole grip the side surface of the wheel nut, and are thereby configured to prevent the wheel nut lock from slipping relative to the wheel nut. For this reason, a load is imposed on handling of the wheel nut.

[0006] A loosening indicator unit for solving the above problems comprises a first loosening indicator and a second loosening indicator. The first loosening indicator comprises a first fastening portion configured to be fastened to a first screw member and a first extension portion extending from the first fastening portion along the circumferential direction of the wheel disc. The second loosening indicator comprises a second fastening portion configured to be fastened to a second screw member and a second extension portion extending from the second fastening portion along the circumferential direction of the wheel disc. The first and second loosening indicators are configured such that the insertion force of the second fastening portion into the second screw member is smaller than the insertion force of the first fastening portion into the first screw member, and at least a portion of the second extension portion is located on the hub side of the wheel disc relative to the first extension portion and overlaps the first extension portion when the second fastening portion is fastened to the second screw member and the first fastening portion is fastened to the first screw member.

[0007] A mounting structure for a loosening indicator unit to solve the above problems comprises a first screw member, a second screw member, and a loosening indicator unit. The loosening indicator unit comprises a first loosening indicator and a second loosening indicator. The first loosening indicator comprises a first fastening portion fastened to the first screw member and a first extension portion extending from the first fastening portion along the circumferential direction of the wheel disc. The second loosening indicator comprises a second fastening portion fastened to the second screw member and a second extension portion extending from the second fastening portion along the circumferential direction of the wheel disc. In the first and second loosening indicators, the fastening force of the second fastening portion to the second screw member is smaller than the fastening force of the first fastening portion to the first screw member, and at least a portion of the second extension portion is located on the hub portion side of the wheel disc relative to the first extension portion and overlaps the first extension portion.

[0008] According to the above-described loosening indicator unit and mounting structure for the loosening indicator unit, the insertion force of the second fastening part is smaller than the insertion force of the first fastening part. Therefore, the load on handling the loosening indicator unit can be reduced compared to the case where the insertion force is the same for all loosening indicators.

[0009] In the above-described loosening indicator unit, the first extension is an indicator section having a shape that tapers toward the direction away from the first fastening section, and the second extension may be an indicator section configured to superimpose on the first extension on the hub side of the wheel disc relative to the first extension when the relative amount of rotation of the first fastening section with respect to the second fastening section is within a predetermined range. According to the above-described loosening indicator unit, the relative amount of rotation of the first fastening section with respect to the second fastening section can be determined by the position of the indicator section relative to the indicator section.

[0010] In the loosening indicator unit described above, the second extension is an indicator portion having a shape that tapers toward the direction away from the second fastening portion, and the first extension has a window portion that penetrates the first extension portion in the direction toward the second extension portion, and the window portion is configured to expose an exposed portion, which is a part of the second extension portion, to the outside of the first extension portion, and the window portion may be configured such that the position of the exposed portion relative to the window portion changes with respect to the change in the relative amount of rotation of the first fastening portion relative to the second fastening portion. According to the loosening indicator unit described above, the relative amount of rotation of the first fastening portion relative to the second fastening portion can be determined by the position of the exposed portion relative to the window portion.

[0011] In the above-described loosening indicator unit, the second loosening indicator is one of a pair of second loosening indicators, the first extension is one of a pair of first extensions, the pair of first extensions sandwich the first fastening portion in the circumferential direction, and when the loosening indicator unit is attached to the wheel disc, a part of the second extension of one of the pair of second loosening indicators is located on the hub portion side of the wheel disc relative to one of the pair of first extensions and overlaps the first extension of the one, and a part of the second extension of the other of the pair of second loosening indicators is located on the hub portion side of the wheel disc relative to the other of the pair of first extensions and overlaps the first extension of the other.

[0012] According to the above-described looseness indicator unit, the second extension of each second looseness indicator is located on the hub side of the wheel disc relative to the first extension and overlaps the first extension. Therefore, the movement of the second extension of one first looseness indicator in the direction from the second extension toward the first extension can be suppressed by the two second looseness indicators.

[0013] In the above-described looseness indicator unit, the first looseness indicator is one of one or more first looseness indicators, the second looseness indicator is one of a plurality of second looseness indicators, the second extension is one of a pair of second extensions, the pair of second extensions sandwich the second fastening portion in the circumferential direction, the pair of second extensions consists of a lower extension closer to the hub portion and an upper extension further from the hub portion, and in the state in which the looseness indicator unit is attached to the wheel disc, each of the one or more first looseness indicators in the circumferential direction The loosening indicator unit is sandwiched between two of the plurality of second loosening indicators, and the two second loosening indicators are arranged such that their lower extensions and upper extensions are alternately aligned, and in two second loosening indicators adjacent to each other in the circumferential direction, the lower extension of one of the two second loosening indicators is positioned on the hub side of the wheel disc and superimposed on the upper extension of the other second loosening indicator, and the loosening indicator unit is configured to have an annular shape concentric with the wheel disc.

[0014] According to the above-described looseness indicator unit, since the looseness indicator unit has an annular shape concentric with the wheel disc, the aesthetic appearance of the wheel disc to which the looseness indicator unit is attached can be enhanced.

[0015] In the loosening indicator unit described above, each upper extension is provided with a window that penetrates the upper extension in a direction toward the lower extension, and the window is configured to expose an exposed portion, which is a part of the lower extension adjacent to the upper extension, to the outside of the upper extension, and the window may be configured such that the position of the exposed portion relative to the window changes due to a change in the relative amount of rotation between adjacent second fastening portions.

[0016] According to the loosening indicator unit described above, the relative amount of rotation between the second fastening parts can be determined by the position of the exposed part relative to the window.

[0017] In the loosening indicator unit described above, the lower extension is an indicator portion that tapers toward the direction away from the second fastening portion to which the lower extension is connected, and the width of the window portion may be greater than the width of the exposed portion in the direction intersecting the circumferential direction.

[0018] According to the loosening indicator unit described above, the relative amount of rotation between the second fastening parts can be determined by the position in which the exposed parts overlap within the window.

[0019] According to this disclosure, the load on handling the loosening indicator unit and the mounting structure for the loosening indicator unit can be reduced.

[0020] Figure 1 is a perspective view showing the structure of the first loosening indicator in the loosening indicator unit. Figure 2 is a perspective view showing the structure of the second loosening indicator in the loosening indicator unit. Figure 3 is an end view showing the structure of the first loosening indicator together with the structure of the nut. Figure 4 is an end view showing the structure of the second loosening indicator together with the structure of the nut. Figure 5 is a plan view showing the structure of the loosening indicator unit attached to the wheel disc. Figure 6 is a plan view illustrating a method for determining the amount of rotation of the nut using the loosening indicator unit. Figure 7 is a plan view illustrating a method for determining the amount of rotation of the nut using the loosening indicator unit. Figure 8 is a plan view showing a first modified example of the loosening indicator unit. Figure 9 is a plan view showing a second modified example of the loosening indicator unit. Figure 10 is a plan view showing a third modified example of the loosening indicator unit.

[0021] An embodiment of a loosening indicator unit and a mounting structure for the loosening indicator unit will be described with reference to Figures 1 to 7. The loosening indicator unit of this disclosure comprises one or more first loosening indicators and one or more second loosening indicators. Before describing the structure of the loosening indicator unit, the structure of the first loosening indicator and the structure of the second loosening indicator provided in the loosening indicator unit will be described below.

[0022] [Looseness Indicator] The first looseness indicator and the second looseness indicator will be described with reference to Figures 1 to 4. As shown in Figure 1, the first looseness indicator 11 comprises a first fastening portion 11A and a pair of first extension portions 11B. The first looseness indicator 11 is a resin molded product in which the first fastening portion 11A and the pair of first extension portions 11B are integrally molded.

[0023] The first fastening portion 11A is fastened to the first nut N1 (see Figure 3). The first nut N1 is an example of a first screw-type member. The first fastening portion 11A has a cylindrical shape that extends along the axial direction DAN1 (see Figure 3) of the first nut N1. The first fastening portion 11A has an uneven surface 11AS that contacts the first nut N1. The uneven surface 11AS has a plurality of convex surfaces that project toward the region defined by the first fastening portion 11A. Each convex surface extends along the axial direction DAN1 of the first nut N1.

[0024] Each first extension 11B extends from the first fastening portion 11A along the circumferential direction of the wheel disc W (see Figure 5). A pair of first extensions 11B consists of a first indicator portion 11B1 and a first display portion 11B2. The first indicator portion 11B1 has a shape that tapers toward the direction away from the first fastening portion 11A. In the example shown in Figure 1, when viewed from a line of sight parallel to the axial direction DAN1 of the first nut N1, the first indicator portion 11B1 has a triangular plate shape extending from the end of the outer circumferential surface of the first fastening portion 11A.

[0025] The first display section 11B2 is located on the opposite side of the first indicator section 11B1 from the first fastening section 11A when viewed from a line of sight parallel to the axial DAN1 of the first nut N1. When viewed from a line of sight parallel to the axial DAN1 of the first nut N1, the first display section 11B2 has a substantially rectangular shape that extends from the inferior arc of the first fastening section 11A toward the opposite side of the first indicator section 11B1.

[0026] The first display section 11B2 comprises a first display wall 11B21 and a pair of first side walls 11B22. The first display wall 11B21 has a substantially rectangular plate shape extending from the position between the pair of ends on the outer circumferential surface of the first fastening section 11A. Of the edges of the first display wall 11B21, the edge opposite to the edge connected to the first fastening section 11A has an arc portion that includes the outer end in the radial direction of the wheel disc W. The radial direction of the wheel disc W is an example of a direction that intersects the circumferential direction of the wheel disc W. The curvature of the arc portion is equal to the curvature of the first fastening section 11A. Also, of the edges of the first display wall 11B21, the edge opposite to the edge connected to the first fastening section 11A has a straight portion that includes the inner end in the radial direction of the wheel disc W. The straight portion is connected to the arc portion and extends along the tangential direction of the arc portion.

[0027] The two first side walls 11B22 have an arc shape with the center of curvature being the center of the wheel disc W. The two first side walls 11B22 are spaced apart in the radial direction of the wheel disc W. Each first side wall 11B22 has the same length as the first fastening portion 11A in the axial direction DAN1 of the first nut N1. Of the pair of first side walls 11B22, one first side wall 11B22 is in contact with one of a pair of edges extending along the circumferential direction of the wheel disc W within the first indicator wall 11B21, and the other first side wall 11B22 is in contact with the other of the pair of edges.

[0028] The first display section 11B2 has a first window section 11B2H that penetrates the first display section 11B2 along the axial DAN 1 of the first nut N1. The first window section 11B2H penetrates the first display wall 11B21 of the first display section 11B2 along the axial DAN 1 of the first nut N1. The first window section 11B2H has a substantially elliptical shape that extends along the radial direction of the wheel disc W.

[0029] As shown in Figure 2, the second loosening indicator 12 comprises a second fastening portion 12A and a pair of second extension portions 12B. The second loosening indicator 12 is a resin molded product in which the second fastening portion 12A and the pair of second extension portions 12B are integrally molded.

[0030] The second fastening portion 12A is fastened to the second nut N2 (see Figure 4). The second nut N2 is an example of a second screw-type member. The second fastening portion 12A has a cylindrical shape that extends along the axial direction DAN2 (see Figure 4) of the second nut N2. The second fastening portion 12A has an uneven surface 12AS that contacts the second nut N2. The uneven surface 12AS has a plurality of convex surfaces that protrude toward the region defined by the second fastening portion 12A. Each protruding surface extends along the axial direction DAN2 of the second nut N2. The shape and size of the second fastening portion 12A are the same as those of the first fastening portion 11A.

[0031] Each second extension 12B extends from the second fastening portion 12A along the circumferential direction of the wheel disc W. A pair of second extensions 12B consists of a second indicator portion 12B1 and a second display portion 12B2. The second indicator portion 12B1 is an example of a lower extension portion that is close to the hub portion WH. The second display portion 12B2 is an example of an upper extension portion that is far from the hub portion WH. The hub portion WH of the wheel disc is the part of the wheel disc to which the hub is fastened, and is a disc-shaped portion in which bolt holes are formed.

[0032] The second indicator portion 12B1 has a shape that tapers away from the second fastening portion 12A. In the example shown in Figure 2, when viewed from a line of sight parallel to the axial direction DAN2 of the second nut N2, the second indicator portion 12B1 has a triangular plate shape extending from between a pair of ends on the outer circumferential surface of the second fastening portion 12A. The shape and size of the second indicator portion 12B1 are the same as those of the first indicator portion 11B1.

[0033] The second display section 12B2 is located on the opposite side of the second indicator section 12B1 from the second fastening section 12A when viewed from a line of sight parallel to the axial DAN2 of the second nut N2. When viewed from a direction parallel to the axial DAN2 of the second nut N2, the second display section 12B2 has a substantially rectangular shape that extends from the inferior arc of the second fastening section 12A toward the opposite side of the second indicator section 12B1. The shape and size of the second display section 12B2 are the same as those of the first display section 11B2.

[0034] The second display section 12B2 comprises a second display wall 12B21 and a pair of second side walls 12B22. The second display wall 12B21 has a substantially rectangular plate shape extending from the position between the pair of ends on the outer circumferential surface of the second fastening section 12A. Of the edges of the second display wall 12B21, the side opposite to the side connected to the second fastening section 12A has an arc portion that includes the outer end in the radial direction of the wheel disc W. The curvature of the arc portion is equal to the curvature of the second fastening section 12A. Also, of the edges of the second display wall 12B21, the side opposite to the side connected to the second fastening section 12A has a straight portion that includes the inner end in the radial direction of the wheel disc W. The straight portion connects to the arc portion and extends along the tangential direction of the arc portion.

[0035] In the axial DAN2 of the second nut N2, the position of the second indicator wall 12B21 is equal to the position of the first indicator wall 11B21. In the axial DAN2 of the second nut N2, the second indicator wall 12B21 and the first indicator wall 11B21 are sandwiched between the first indicator part 11B1 and the second indicator part 12B1. That is, in the axial DAN2 of the second nut N2, the second indicator wall 12B21 and the first indicator wall 11B21 are located between the first indicator part 11B1 and the second indicator part 12B1.

[0036] The two second side walls 12B22 have an arc shape with the center of curvature being the center of the wheel disc W. The two second side walls 12B22 are spaced apart in the radial direction of the wheel disc W. Each second side wall 12B22 has the same length as the second fastening portion 12A in the axial direction DAN2 of the second nut N2. Of the pair of second side walls 12B22, one second side wall 12B22 is in contact with one of a pair of edges that extend along the circumferential direction of the wheel disc W within the second indicator wall 12B21, and the other second side wall 12B22 is in contact with the other of the pair of edges.

[0037] The second display section 12B2 has a second window section 12B2H that penetrates the second display section 12B2 along the axial DAN2 of the second nut N2. The second window section 12B2H penetrates the second display wall 12B21 of the second display section 12B2 along the axial DAN2 of the second nut N2. The second window section 12B2H has a substantially elliptical shape that extends along the radial direction of the wheel disc W.

[0038] Figure 3 shows the cross-sectional structure of the first fastening portion 11A and the first nut N1, viewed from a line of sight parallel to the axial DAN1 of the first nut N1, along a plane that passes through the diameter of the first fastening portion 11A and extends along the axial DAN1. Figure 3 shows the state of the first nut N1 and the first fastening portion 11A during the process of attaching the first fastening portion 11A to the first nut N1.

[0039] As shown in Figure 3, the uneven surface 11AS of the first fastening portion 11A includes a first uneven surface 11AS1 and a second uneven surface 11AS2. The first uneven surface 11AS1 and the second uneven surface 11AS2 are aligned along the axial direction DAN1 of the first nut N1. The inner diameter D11A of the first uneven surface 11AS1 is smaller than the inner diameter D11B of the second uneven surface 11AS2. The first fastening portion 11A is fastened to the first nut N1 such that the second uneven surface 11AS2 contacts the first nut N1 before the first uneven surface 11AS1.

[0040] The outer diameter DN1 of the first nut N1 is approximately equal to the inner diameter D11B of the second uneven surface 11AS2, and is larger than the inner diameter D11A of the first uneven surface 11AS1. Therefore, when attaching the first fastening portion 11A to the first nut N1, the first nut N1 is press-fitted into the first fastening portion 11A in such a way that it expands the first uneven surface 11AS1 of the first fastening portion 11A in the radial direction of the first fastening portion 11A. As a result, the insertion force required to insert the first nut N1 into the first fastening portion 11A is high.

[0041] Figure 4 shows the cross-sectional structure of the second fastening portion 12A and the second nut N2, viewed from a line of sight parallel to the axial DAN2 of the second nut N2, along a plane that passes through the diameter of the second fastening portion 12A and extends along the axial DAN2. Figure 4 shows the state of the second nut N2 and the second fastening portion 12A during the process of attaching the second fastening portion 12A to the second nut N2.

[0042] As shown in Figure 4, the uneven surface 12AS of the second fastening portion 12A includes a first uneven surface 12AS1 and a second uneven surface 12AS2. The first uneven surface 12AS1 and the second uneven surface 12AS2 are aligned along the axial direction DAN2 of the second nut N2. The inner diameter D12A of the first uneven surface 12AS1 is smaller than the inner diameter D12B of the second uneven surface 12AS2. The second fastening portion 12A is fastened to the second nut N2 such that the second nut N2 is inserted into the second uneven surface 12AS2 before the first uneven surface 12AS1.

[0043] An outer diameter DN2 of the second nut N2 is equal to an outer diameter DN1 of the first nut N1. An inner diameter D12B of the second uneven surface 12AS2 is larger than the outer diameter DN2 of the second nut N2, and an inner diameter D12A of the first uneven surface 12AS1 is substantially equal to the outer diameter DN2 of the second nut N2. Therefore, an insertion force of the second fastening portion 12A, which is a force required when inserting the second fastening portion 12A onto the second nut N2, is smaller than an insertion force of the first fastening portion 11A, which is a force required when inserting the first fastening portion 11A onto the first nut N1.

[0044] [Looseness indicator unit] The looseness indicator unit 10 will be described with reference to FIG. 5. In the example shown in FIG. 5, the looseness indicator unit 10 includes one first looseness indicator 11 and nine second looseness indicators 12.

[0045] When attaching the looseness indicator unit 10 shown in FIG. 5 to a wheel disc W, for example, first, the second looseness indicator 12 that is in contact with a first indicator portion 11B1 of the first looseness indicator 11 is attached to the second nut N2. Subsequently, one second looseness indicator 12 is attached to one second nut N2 counterclockwise starting from the second looseness indicator 12 positioned immediately to the left of the aforementioned second looseness indicator 12. Finally, by attaching the first looseness indicator 11 to the first nut N1, the looseness indicator unit 10 can be attached to the wheel disc W.

[0046] This forms an attachment structure of the looseness indicator unit 10 that includes the first nut N1, the second nut N2, and the looseness indicator unit 10. In the attachment structure of the looseness indicator unit 10, a fastening force of the second fastening portion 12A against the second nut N2 is smaller than a fastening force of the first fastening portion 11A against the first nut N1.

[0047] The fastening force of the first fastening portion 11A to the first nut N1 is the force required when removing the first fastening portion 11A from the first nut N1. The fastening force of the first fastening portion 11A to the first nut N1 is equal to the insertion force of the first fastening portion 11A into the first nut N1. The fastening force of the second fastening portion 12A to the second nut N2 is the force required when removing the second fastening portion 12A from the second nut N2. The fastening force of the second fastening portion 12A to the second nut N2 is equal to the insertion force of the second fastening portion 12A into the second nut N2.

[0048] In the looseness indicator unit 10, in the first looseness indicator 11 and the second looseness indicator 12 adjacent to the first looseness indicator 11, at least a part of the second extension portion 12B is located on the hub portion WH side of the wheel disc relative to the first extension portion 11B, and overlaps the first extension portion 11B. In the example shown in FIG. 5, among the second looseness indicators 12 located immediately left of the first looseness indicator 11, the second display portion 12B2 is located on the hub portion WH side of the wheel disc W relative to the first indication portion 11B1. Further, among the second looseness indicators 12 located immediately right of the first looseness indicator 11, the second indication portion 12B1 is located on the hub portion WH side of the wheel disc W relative to the first display portion 11B2.

[0049] According to the looseness indicator unit 10, since the insertion force of the second fastening portion 12A is smaller than the insertion force of the first fastening portion 11A, compared to a case where the insertion force is the same in all of the looseness indicators 11 and 12, the load involved in handling the looseness indicator unit 10 can be reduced. In the looseness indicator unit 10 of the present embodiment, the load when attaching the looseness indicator unit 10 to the wheel disc W and the load when detaching the same can be reduced. Moreover, the second extension portion 12B is located on the hub portion WH side of the wheel disc W relative to the first extension portion 11B, and overlaps the first extension portion 11B. Accordingly, movement of the second extension portion 12B in a direction from the second extension portion 12B toward the first extension portion 11B is suppressed by the first extension portion 11B.

[0050] Furthermore, as described above, one example of the second extension 12B, the second display unit 12B2, is located on the hub portion WH side of the wheel disc W relative to the first instruction unit 11B1, which is an example of the first extension 11B, and superimposes on the first instruction unit 11B1. Similarly, the other example of the second extension 12B, the second instruction unit 12B1, is located on the hub portion WH side of the wheel disc W relative to the first display unit 11B2, which is an example of the other first extension 11B, and superimposes on the first display unit 11B2. Therefore, one first looseness indicator 11 can prevent the second extension 12B from moving in the direction from the second extension 12B toward the first extension 11B using two second looseness indicators 12.

[0051] In the nine second looseness indicators 12 included in the looseness indicator unit 10, a second instruction portion 12B1, which is an example of a lower extension portion, and a second display portion 12B2, which is an example of an upper extension portion, are arranged alternately in the circumferential direction of the wheel disc W. Furthermore, in adjacent second looseness indicators 12 in the circumferential direction of the wheel disc W, the second instruction portion 12B1 of one second looseness indicator 12 is located on the hub portion WH side of the wheel disc W relative to the second display portion 12B2 of the other second looseness indicator 12, and superimposes on the second display portion 12B2. As a result, the looseness indicator unit 10 has a concentric annular shape with respect to the wheel disc W. Because the looseness indicator unit 10 has a concentric annular shape with respect to the wheel disc W, the aesthetic appearance of the wheel disc W to which the looseness indicator unit 10 is attached can be enhanced.

[0052] Each first side wall 11B22 (see Figure 1) and each second side wall 12B22 (see Figure 2) have an arc shape that follows a virtual circle concentric with the wheel disc W. Therefore, when the loosening indicator unit 10 is attached to the wheel disc W, the loosening indicator unit 10 can have an annular shape concentric with the wheel disc W. In addition, the first indicator wall 11B21 (see Figure 1) has an arc portion on the side that is in contact with the second fastening portion 12A. In addition, each second indicator wall 12B21 (see Figure 2) has an arc portion on the side that is in contact with the first fastening portion 11A or the second fastening portion 12A. As a result, gaps are less likely to occur between adjacent loosening indicators 11 and 12 in the circumferential direction of the wheel disc W, thus further enhancing the aesthetic appearance of the wheel disc W to which the loosening indicator unit 10 is attached.

[0053] On the other hand, the first indicator wall 11B21 has a straight section connected to the arc section that is in contact with the second fastening section 12A. In addition, each second indicator wall 12B21 has a straight section connected to the arc section that is in contact with the first fastening section 11A or the second fastening section 12A. As a result, the movement of the first indicator wall 11B21 accompanying the rotation of the first nut N1 is less likely to be interfered with by the second fastening section 12A adjacent to the first indicator wall 11B21 in the circumferential direction of the wheel disc W. Also, the movement of the second indicator wall 12B21 accompanying the rotation of the second nut N2 is less likely to be interfered with by the first fastening section 11A or the second fastening section adjacent to the second indicator wall 12B21 in the circumferential direction of the wheel disc W.

[0054] Furthermore, the pair of second looseness indicators 12 sandwich the first looseness indicator 11 in the circumferential direction of the wheel. That is, the pair of second looseness indicators 12 are located on both sides of the first looseness indicator 11 in the circumferential direction of the wheel. Therefore, the fastening force at one first fastening portion 11A can be applied to the second looseness indicators 12 other than the pair of second looseness indicators 12 that sandwich the first looseness indicator 11 in the circumferential direction of the wheel. As a result, even if the fastening force of the second fastening portion 12A is smaller than the fastening force of the first fastening portion 11A, one first looseness indicator 11 can make it difficult for all the second looseness indicators 12 to fall off the wheel.

[0055] [Rotation Amount] Referring to Figures 6 and 7, a method for determining the rotation amount of each nut N1 and N2 using the looseness indicator unit 10 will be explained. Figure 6 shows the initial positions of each looseness indicator 11 and 12 when the looseness indicator unit 10 is attached to the wheel disc W. Figure 7 shows the state in which the first looseness indicator 11 is maintained in its initial position, while the position of the second looseness indicator 12, located to the right of the first looseness indicator 11, has changed to a displaced position due to the loosening of the second nut N2.

[0056] As shown in Figure 6, the first window portion 11B2H of the first display portion 11B2, which is an example of the first extension portion 11B, exposes the tip of the second indicator portion 12B1, which is an example of the second extension portion, to the outside of the first display portion 11B2. In the example shown in Figure 6, the tip of the second indicator portion 12B1 is an example of the exposed portion. At the initial position of each looseness indicator 11, 12, the tip of the second indicator portion 12B1 overlaps with the outer end of the first window portion 11B2H in the radial direction of the wheel disc W.

[0057] The first window portion 11B2H is configured such that the position of the exposed portion relative to the first window portion 11B2H changes with the change in the relative amount of rotation of the first fastening portion 11A relative to the second fastening portion 12A. In the example shown in Figure 6, the first window portion 11B2H has a shape that follows the trajectory of the tip of the second indicator portion 12B1 when the second nut N2 loosens, that is, when the second nut N2 rotates counterclockwise. Furthermore, in the radial direction of the wheel disc W, the width of the first window portion 11B2H is greater than the maximum width at the tip of the second indicator portion 12B1. As a result, the relative amount of rotation of the first fastening portion 11A relative to the second fastening portion 12A can be determined by the position of the exposed portion relative to the first window portion 11B2H.

[0058] Of the second loosening indicator 12 located to the left of the first loosening indicator 11, the second display unit 12B2 superimposes on the first indicator unit 11B1 on the hub portion WH side of the wheel disc W relative to the first indicator unit 11B1 when the relative amount of rotation of the first fastening portion 11A relative to the second fastening portion 12A is within a predetermined range. Therefore, the relative amount of rotation of the first fastening portion 11A relative to the second fastening portion 12A can be determined by the position of the first indicator unit 11B1 relative to the second display unit 12B2.

[0059] The tip of the first indicator portion 11B1 overlaps with the outer end of the second window portion 12B2H in the radial direction of the wheel disc W. In the example shown in Figure 6, the second window portion 12B2H has a shape that follows the trajectory of the tip of the first indicator portion 11B1 when the first nut N1 loosens, i.e., when the first nut N1 rotates counterclockwise. Furthermore, in the radial direction of the wheel disc W, the width of the second window portion 12B2H is greater than the maximum width of the tip of the first indicator portion 11B1. As a result, the relative amount of rotation of the first fastening portion 11A with respect to the second fastening portion 12A can be determined by the position of the tip of the second window portion 12B2H.

[0060] Furthermore, the second window portion 12B2H of each second display portion 12B2 exposes the tip of the second indicator portion 12B1 adjacent to the second display portion 12B2 to the outside of the second display portion 12B2. The tip of the second indicator portion 12B1 is an example of the exposed portion. In the initial position of each second looseness indicator 12, the tip of the second indicator portion 12B1 overlaps the radially outer end of the end portion of the second window portion 12B2H that is located in the radial direction of the wheel disc W.

[0061] The second window portion 12B2H is configured such that the position of the exposed portion relative to the second window portion 12B2H changes due to the change in the relative amount of rotation between adjacent second fastening portions 12A. In the example shown in Figure 6, the second window portion 12B2H has a shape that follows the trajectory of the tip of the second indicator portion 12B1 when the second nut N2 rotates counterclockwise. Furthermore, in the radial direction of the wheel disc W, the width of the second window portion 12B2H is greater than the maximum width at the tip of the second indicator portion 12B1. As a result, the relative amount of rotation between the second fastening portions 12A can be determined by the position in which the exposed portion overlaps within the second window portion 12B2H.

[0062] As shown in Figure 7, the position of the tip of the second indicator portion 12B1 relative to the first window portion 11B2H changes as the second nut N2 rotates counterclockwise relative to its initial position. In the example shown in Figure 7, the tip of the second indicator portion 12B1 overlaps the inner end of the first window portion 11B2H in the radial direction of the wheel disc W. At this time, the rotation of the second fastening portion 12A accompanying the rotation of the second nut N2 is restricted by the second indicator portion 12B1 contacting the first side wall 11B22.

[0063] In this way, the position of the tip of the second indicator portion 12B1 relative to the first window portion 11B2H differs between the initial position and the displacement position, making it possible to determine the relative amount of rotation of the first fastening portion 11A relative to the second fastening portion 12A.

[0064] As described above, according to one embodiment of the loosening indicator unit and the mounting structure for the loosening indicator unit, the following effects can be obtained: (1) Since the insertion force of the second fastening part 12A is smaller than the insertion force of the first fastening part 11A, the load on handling the loosening indicator unit 10 can be reduced compared to the case where the insertion force is the same for all loosening indicators 11 and 12.

[0065] (2) The second extension 12B is located on the hub portion WH side of the wheel disc W relative to the first extension 11B and overlaps the first extension 11B. Therefore, the movement of the second extension 12B in the direction from the second extension 12B toward the first extension 11B is suppressed by the first extension 11B.

[0066] (3) The position of the first indicator unit 11B1 relative to the second display unit 12B2 allows us to determine the relative amount of rotation of the first fastening unit 11A relative to the second fastening unit 12A.

[0067] (4) The relative amount of rotation of the first fastening portion 11A with respect to the second fastening portion 12A can be determined by the position of the exposed portion relative to the first window portion 11B2H.

[0068] (5) One first loosening indicator 11 can prevent the second extension 12B from moving in the direction from the second extension 12B toward the first extension 11B using two second loosening indicators 12.

[0069] (6) Since the looseness indicator unit 10 has an annular shape concentric with the wheel disc W, the aesthetic appearance of the wheel disc W to which the looseness indicator unit 10 is attached can be enhanced.

[0070] (7) The relative amount of rotation between the second fastening parts 12A can be determined by the position of the exposed part relative to the second window part 12B2H. (8) The relative amount of rotation between the second fastening parts 12A can be determined by the position where the exposed part overlaps within the second window part 12B2H.

[0071] [Example of modification] The above-described embodiment can be modified and implemented as follows: [Looseness indicator] As shown in Figure 8, the looseness indicator unit 20 may consist of only one first looseness indicator 21 and one second looseness indicator 22. In this case, the first looseness indicator 21 may consist of only one first extension 21B extending from the first fastening portion 21A, and the second looseness indicator 22 may consist of only one second extension 22B extending from the second fastening portion 22A. Even with this configuration, the second extension 22B can be positioned on the hub portion WH side of the wheel disc W relative to the first extension 21B and superimposed on the first extension 21B to obtain the effects similar to (1) and (2) described above.

[0072] Furthermore, if the second extension 22B is an indicator portion that tapers toward the direction away from the second fastening portion 22A, it is preferable that the first extension 21B includes a first window portion that exposes the exposed portion of the second extension 22B. Note that if the loosening indicator unit 20 includes only two loosening indicators 11 and 12, multiple loosening indicator units 20 may be attached to a single wheel disc W.

[0073] - As shown in Figure 9, if the loosening indicator unit 30 is equipped with only one first loosening indicator 31 and one second loosening indicator 32, the first extension 31B may be an indicator that tapers toward the direction away from the first fastening portion 31A. In this case, the relative amount of rotation of the first fastening portion 31A relative to the second fastening portion 32A can be determined by the position of the first extension 31B relative to the second extension 32B that superimposes on the first extension 31B.

[0074] In the modified examples shown in Figures 8 and 9, the first extensions 21B, 31B and the second extensions 22B, 32B may have the same shape as each other. Even in this case, the effects similar to those described in (1) and (2) above can be obtained.

[0075] As shown in Figure 10, in the first loosening indicator 41 of the loosening indicator unit 40, the first fastening portion 41A sandwiched between a pair of first extensions 41B may comprise a first outer member 41A1 and a first inner member 41A2. The first inner member 41A2 is fixed to the first outer member 41A1 and configured to be fastened to the first nut N1. The pair of first extensions 41B are connected to the first outer member 41A1.

[0076] Furthermore, in the second loosening indicator 42, the second fastening portion 42A, which is sandwiched between a pair of second extensions 42B, may include a second outer member 42A1 and a second inner member 42A2. The second inner member 42A2 is fixed to the second outer member 42A1 and configured to be fastened to the second nut N2. A pair of second extensions 42B are connected to the second outer member 42A1.

[0077] Furthermore, as shown in Figure 10, if the pair of first extensions 41B are a first indicator 41B1 and a first display 41B2, it is preferable that the first display 41B2 has a first window portion that penetrates the first display 41B2 in the axial direction of the first nut N1. Also, if the pair of second extensions 42B are a first indicator 42B1 and a second display 42B2, it is preferable that the second display 42B2 has a second window portion that penetrates the second display 42B2 in the axial direction of the second nut N2.

[0078] [Insertion Force] The insertion force of the first fastening portion 11A may be made greater than that of the second fastening portion 12A by using a different material for forming the first fastening portion 11A than for forming the second fastening portion 12A. In this case, the rigidity of the material forming the first fastening portion 11A should be made higher than that of the material forming the second fastening portion 12A.

[0079] [Looseness Indicator Unit] The looseness indicator unit 10 may be provided with one or more first looseness indicators 11 and one or more second looseness indicators 12. Therefore, the looseness indicator unit 10 may be provided with one first looseness indicator 11 and multiple second looseness indicators 12, or with multiple first looseness indicators 11 and one second looseness indicator 12. Alternatively, the looseness indicator unit 10 may be provided with multiple first looseness indicators 11 and multiple second looseness indicators 12.

[0080] [Threaded Members] The threaded member to which the first fastening portion 11A of the first loosening indicator 11 is fastened is not limited to a nut but may also be a bolt. Similarly, the threaded member to which the second fastening portion 12A of the second loosening indicator 12 is fastened is not limited to a nut but may also be a bolt.

[0081] 10...Looseness indicator unit 11...First looseness indicator 11A...First fastening part 11B...First extension part 11B1...First indicator part 11B2...First display part 12...Second looseness indicator 12A...Second fastening part 12B...Second extension part 12B1...Second indicator part 12B2...Second display part N1...First nut N2...Second nut

Claims

1. A loosening indicator unit comprising a first loosening indicator and a second loosening indicator, wherein the first loosening indicator comprises a first fastening portion configured to be fastened to a first screw member and a first extension portion extending from the first fastening portion along the circumferential direction of the wheel disc, and the second loosening indicator comprises a second fastening portion configured to be fastened to a second screw member and a second extension portion extending from the second fastening portion along the circumferential direction of the wheel disc, wherein the insertion force of the second fastening portion to the second screw member is smaller than the insertion force of the first fastening portion to the first screw member, and with the second fastening portion fastened to the second screw member and the first fastening portion fastened to the first screw member, at least a portion of the second extension portion is positioned on the hub portion side of the wheel disc relative to the first extension portion and superimposed on the first extension portion.

2. The loosening indicator unit according to claim 1, wherein the first extension is an indicator having a shape that tapers toward the direction away from the first fastening portion, and the second extension is a display portion configured to superimpose on the first extension on the hub portion side of the wheel disc relative to the first extension when the relative amount of rotation of the first fastening portion with respect to the second fastening portion is within a predetermined range.

3. The loosening indicator unit according to claim 1, wherein the second extension is an indicator portion having a shape that tapers toward the direction away from the second fastening portion, the first extension is provided with a window portion that penetrates the first extension portion in a direction toward the second extension portion, the window portion is configured to expose an exposed portion which is a part of the second extension portion to the outside of the first extension portion, and the window portion is configured such that the position of the exposed portion relative to the window portion changes due to a change in the relative amount of rotation of the first fastening portion with respect to the second fastening portion.

4. The loosening indicator unit according to claim 1, wherein the second loosening indicator is one of a pair of second loosening indicators, the first extension is one of a pair of first extensions, the pair of first extensions sandwich the first fastening portion in the circumferential direction, and when the loosening indicator unit is attached to the wheel disc, a part of the second extension of one of the pair of second loosening indicators is located on the hub portion side of the wheel disc with respect to one of the pair of first extensions and overlaps with the first extension of one of the second second loosening indicators, and a part of the second extension of the other of the pair of second loosening indicators is located on the hub portion side of the wheel disc with respect to the other of the pair of first extensions and overlaps with the first extension of the other of the pair.

5. The first loosening indicator is one of one or more first loosening indicators, the second loosening indicator is one of a plurality of second loosening indicators, the second extension is one of a pair of second extensions, the pair of second extensions sandwich the second fastening portion in the circumferential direction, the pair of second extensions consists of a lower extension closer to the hub portion and an upper extension further from the hub portion, and when the loosening indicator unit is attached to the wheel disc, in the circumferential direction, each of the one or more first loosening indicators is sandwiched between two of the plurality of second loosening indicators, and the two second loosening indicators are arranged such that their lower extensions and upper extensions alternate. The loosening indicator unit according to claim 4, wherein in two second loosening indicators adjacent to each other in the circumferential direction, the lower extension of one of the two second loosening indicators is positioned on the hub side of the wheel disc and superimposed on the upper extension of the other of the two second loosening indicators, and the loosening indicator unit is configured to have an annular shape concentric with the wheel disc.

6. The loosening indicator unit according to claim 5, wherein each upper extension is provided with a window portion that penetrates the upper extension in a direction toward the lower extension, the window portion is configured to expose an exposed portion which is a part of the lower extension adjacent to the upper extension to the outside of the upper extension, and the window portion is configured such that the position of the exposed portion relative to the window portion changes due to a change in the relative amount of rotation between adjacent second fastening portions.

7. The lower extension is an indicator portion having a shape that tapers toward the direction away from the second fastening portion to which the lower extension is connected, and the width of the window portion is greater than the width of the exposed portion in the direction intersecting the circumferential direction, as described in claim 6.

8. A mounting structure for a loosening indicator unit comprising a first screw member, a second screw member, and a loosening indicator unit, wherein the loosening indicator unit comprises a first loosening indicator and a second loosening indicator, the first loosening indicator comprises a first fastening portion fastened to the first screw member and a first extension portion extending from the first fastening portion along the circumferential direction of the wheel disc, the second loosening indicator comprises a second fastening portion fastened to the second screw member and a second extension portion extending from the second fastening portion along the circumferential direction of the wheel disc, and the mounting structure for the loosening indicator unit wherein the fastening force of the second fastening portion to the second screw member is smaller than the fastening force of the first fastening portion to the first screw member, and at least a portion of the second extension portion is located on the hub portion side of the wheel disc relative to the first extension portion and overlaps the first extension portion.

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