Grommets, cable mounting structures, and methods for manufacturing grommets

Abstract

This grommet makes it easier to determine the mounting angle when attaching the cable and grommet to the bracket, improving the efficiency of the installation work, and also prevents the cable and grommet from rotating or falling off the bracket due to cable movement. [Solution] The grommet 3, which is provided around the cable 2 and attached to the bracket 4, comprises a cylindrical main body 30 fused and fixed to the sheath of the cable 2, and a fitting portion 32 provided on the outer circumferential wall of the main body 30 along the circumferential direction D2 and fitting into a mounting hole 40 formed in the bracket 4. The fitting portion 32 has a polygonal shape in a cross-section that intersects the direction in which the cable 2 extends.

Description

Technical Field

[0001] The present invention relates to grommets, a cable attachment structure, and a method for manufacturing grommets.

Background Art

[0002] Conventionally, various systems such as an Anti-lock Braking System (ABS) have been mounted on vehicles. A cable connected to a sensor of such a system is attached to a swing portion around the wheels of the vehicle via a cylindrical grommet. Specifically, a grommet is attached to the cable, and the grommet is attached to a bracket provided on a component of the vehicle.

[0003] Patent Document 1 discloses a grommet having a main body portion in which a groove portion is formed along the circumferential direction of a cable. The grommet is attached to the bracket by accommodating a peripheral edge portion of a hole formed in the bracket in the groove portion formed in the main body portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the cable and the grommet need to be attached to the bracket at a specified attachment angle, the cable and the grommet are rotated by a predetermined angle in the circumferential direction for adjustment and then attached to the bracket. However, depending on the shape of the groove portion of the grommet, it is difficult to grasp how much the cable and the grommet have been rotated, which has had an adverse effect on the attachment work. Further, depending on the shape of the groove portion of the grommet, there has been a problem that the cable and the grommet rotate with respect to the bracket and fall off as the cable swings.

[0006] The object of the present invention is to provide a grommet that makes it easier to determine the mounting angle when attaching the cable and grommet to the bracket, thereby improving the work efficiency of the installation work, and also prevents the cable and grommet from rotating or falling off the bracket due to the swinging of the cable. [Means for solving the problem]

[0007] A grommet in a typical embodiment is provided around a cable and attached to a bracket. The grommet comprises a cylindrical body portion fused to the cable sheath, and a fitting portion provided along the circumferential direction on the outer wall of the body portion, which fits into a mounting hole formed in the bracket. The fitting portion has a polygonal shape in a cross-section intersecting the direction in which the cable extends. [Effects of the Invention]

[0008] According to a typical embodiment, it becomes easier to determine the mounting angle when attaching the cable and grommet to the bracket, improving the efficiency of the installation work, and preventing the cable and grommet from rotating relative to the bracket and falling off due to cable movement. [Brief explanation of the drawing]

[0009] [Figure 1] These are external side views of the mounting structures of the first and second embodiments. [Figure 2] Figure 1 shows a cross-sectional view of the cable and grommet along line AA. [Figure 3] This is an external view of the bracket as seen from the direction of cable extension. [Figure 4] This is a cross-sectional view showing the mounting state of the grommet and bracket. [Figure 5] This is a cross-sectional view of the cable and grommet in the comparative example. [Figure 6] This is an external view of the bracket in the comparative example. [Figure 7]This is a cross-sectional view showing the mounting state of the grommet and bracket in a comparative example. [Figure 8] This is a cross-sectional view of the cable and grommet according to the second embodiment. [Figure 9] This is an external view of the bracket according to the second embodiment. [Figure 10] This is a cross-sectional view showing the mounting state of the grommet and bracket in the second embodiment. [Figure 11] This figure schematically shows a cross-section of a mold used to manufacture a grommet according to the second embodiment. [Figure 12] This diagram schematically shows the cross-section of the mold and grommet when the mold is divided. [Figure 13] This is a cross-sectional view of a modified cable and grommet. [Figure 14] This diagram schematically shows a cross-section of a mold used to manufacture a modified grommet. [Modes for carrying out the invention]

[0010] The embodiments described below will now be explained. Note that the embodiments described below are merely examples for carrying out the present invention and do not limit the technical scope of the present invention. Furthermore, in the following embodiments, components having the same function are denoted by the same reference numerals, and repeated descriptions thereof are omitted unless particularly necessary.

[0011] <First Embodiment> <Overall Structure> Figure 1 is an external side view of the mounting structure 1 for the cable 2 according to the first embodiment. The mounting structure 1 is a structure for attaching the cable 2 to a swinging part, such as the undercarriage of a vehicle. The mounting structure 1 comprises a grommet 3 and a bracket 4. The grommet 3 is attached to the cable 2. The grommet 3 is attached to the bracket 4, which is attached to a component 11 that makes up the vehicle. In this way, the cable 2 is attached to the vehicle.

[0012] Figure 2 is a cross-sectional view of cable 2 and grommet 3 taken along line A-A of Figure 1. Cable 2 is, for example, a cable for an ABS (Anti-lock Braking System) sensor provided around the vehicle's undercarriage. However, the use of cable 2 is not limited to the above. Cable 2 is composed of a plurality of insulated wires with an insulator formed on the outer periphery of the central conductor, and a common sheath 21 that collectively covers the plurality of insulated wires. Note that cable 2 is not limited to the above configuration.

[0013] <Grommet 3> Grommet 3 is provided around cable 2. Grommet 3 is made of a synthetic resin such as ethylene propylene diene rubber (EPDM), for example. Grommet 3 has a main body portion 30, a swinging end portion 31, and a fitting portion 32.

[0014] The main body portion 30 is cylindrical. The thickness of the main body portion 30, that is, the length between the inner peripheral wall and the outer peripheral wall 30a in the radial direction, is thicker than the thickness of the swinging end portion 31 described later. Cable 2 is inserted inside the main body portion 30. More specifically, the inner peripheral wall of the main body portion 30 is fusion-fixed to the sheath 21 of cable 2. For this reason, bending in the main body portion 30 is suppressed.

[0015] The swinging end portion 31 is formed on one end side of the main body portion 30 in the extending direction D1 of cable 2 extending from the main body portion 30. The swinging end portion 31 is integrally formed with the main body portion 30. The swinging end portion 31 is cylindrical and extends along the extending direction D1. By inserting cable 2 inside the swinging end portion 31, the swinging end portion 31 covers the periphery of cable 2. The swinging end portion 31 is not fusion-fixed to the sheath 21 of cable 2 and is in close contact with the sheath 21. And as described above, the thickness of the swinging end portion 31 is smaller than the thickness of the main body portion 30. For this reason, the swinging end portion 31 can be bent according to the handling of cable 2. That is, the swinging end portion 31 guides the extending direction of cable 2 extending from the main body portion 30.

[0016] The fitting portion 32 is formed along the circumferential direction D2 on the outer peripheral wall 30a of the main body portion 30. The grommet 3 is attached to the bracket 4 by fitting the fitting portion 32 into the mounting hole 40 formed in the bracket 4, which will be described later.

[0017] As shown in Figure 2, in the radial direction of the main body 30 (i.e., cable 2), the length of the fitting portion 32 is shorter than the diameter of the main body 30. The fitting portion 32 is formed in a hexagonal shape in a cross section that intersects (orthogonal or nearly orthogonal to) the extension direction D1. Specifically, the fitting portion 32 has six planar wall surfaces 32a, 32b, 32c, 32d, 32e, and 32f. In other words, the fitting portion 32 has angles formed at 60° intervals along the circumferential direction D2 of the main body 30.

[0018] In the following description, the shape of the fitting portion 32 in a cross-section that intersects (orthogonal to or nearly orthogonal to) the extension direction D1 may be referred to as the cross-sectional shape. Furthermore, the cross-sectional shape of the fitting portion 32 is not limited to a hexagon, but may be a polygon with fewer than 6 or 7 or more angles. However, it is preferable that the cross-sectional shape of the fitting portion 32 be a polygon with 12 or fewer angles.

[0019] <Bracket 4> Figure 3 is an external view of the bracket 4 as seen from the extension direction D1 of the cable 2. Figure 4 is a diagram showing the mounting state of the grommet 3 and bracket 4 as seen from the extension direction D1, and is a cross-sectional view of the mounting structure 1 along line AA in Figure 1.

[0020] The bracket 4 is a plate-shaped component that is attached to the vehicle body steel plate on which the cable 2 is installed by welding, screws, or other means. Mounting holes 40 are formed in the bracket 4.

[0021] The mounting hole 40 is a through hole that penetrates the bracket 4 in the extension direction D1. The mounting hole 40 is composed of a communication portion 41 and a housing portion 42. The communication portion 41 is a notch formed on one side 4a of the bracket 4. The communication portion 41 connects the housing portion 42 to the outside of the bracket 4.

[0022] The housing portion 42 has a polygonal contour corresponding to the polygonal cross-sectional shape of the fitting portion 32 formed in the grommet 3. In this embodiment, the housing portion 42 is a polygon corresponding to a part of the hexagonal cross-sectional shape of the fitting portion 32. Specifically, the contour of the housing portion 42 is formed by planar inner wall surfaces 42a, 42b, 42c, and 42d.

[0023] As shown in Figure 4, when the grommet 3 is attached to the bracket 4, a portion of the fitting portion 32 is housed within the housing portion 42, and the remaining portion of the fitting portion 32 is located in the communication portion 41. Specifically, the wall surfaces 32a, 32b, 32c, and 32d of the fitting portion 32 face the inner wall surfaces 42a, 42b, 42c, and 42d of the housing portion 42, respectively. Therefore, the angles formed between the wall surfaces 32a, 32b, 32c, and 32d of the fitting portion 32 and the angles formed between the inner wall surfaces 42a, 42b, 42c, and 42d of the housing portion 42 restrict the grommet 3 from rotating in the circumferential direction D2 relative to the bracket 4. In other words, the rotation of the grommet 3 in the circumferential direction D2 due to the swinging of the cable 2 after it has been attached to the bracket 4 is suppressed.

[0024] <Attaching grommet 3 to bracket 4> When attaching the grommet 3 to the bracket 4, the fitting portion 32 passes through the communication portion 41 and is then housed in the housing portion 42. Specifically, depending on the routing of the cable 2, the cable 2 and grommet 3 are rotated (twisted) by a predetermined mounting angle in the circumferential direction D2, and the fitting portion 32 passes through the communication portion 41 and is then housed in the housing portion 42. Alternatively, with the fitting portion 32 housed in the housing portion 42, the cable 2 and grommet 3 are rotated by the worker by the mounting angle. This causes the fitting portion 32 to engage with the mounting hole 40, and the grommet 3 is attached to the bracket 4. In other words, the cable 2 is attached to the bracket 4 via the grommet 3. The mounting angle is also called the phase angle.

[0025] In this embodiment, the polygonal cross-sectional shape of the fitting portion 32 and the polygonal contour of the housing portion 42 are formed to correlate with the mounting angle. Specifically, the fitting portion 32, which is formed with a hexagonal cross-sectional shape, can accommodate a mounting angle of 60° for the cable 2. That is, when installing the grommet 3, the angle of the grommet 3 can be adjusted in 60° increments along the circumferential direction D2. Therefore, when installing the cable 2 and grommet 3, the worker can easily determine that the cable 2 and grommet 3 have been twisted and rotated in the circumferential direction D2 to achieve the desired mounting angle.

[0026] As described above, the cross-sectional shape of the fitting portion 32 and the contour of the housing portion 42 of the bracket 4 are polygonal. Therefore, when the cable 2 swings, the grommet 3 is prevented from rotating in accordance with the cable 2. In other words, the fitting portion 32 and the mounting hole 40 function as anti-rotation devices for the grommet 3.

[0027] Furthermore, if the mounting angle is greater than 60°, the number of corners in the polygon of the fitting portion 32 will be less than 6. For example, if the mounting angle is 90°, the number of corners in the polygon of the fitting portion 32 will be 4. Also, if the mounting angle is less than 60°, the number of corners in the polygon of the fitting portion 32 will be more than 6. For example, if the mounting angle is 45°, the number of corners in the polygon of the fitting portion 32 will be 8.

[0028] According to the first embodiment described above, the following effects and advantages can be obtained.

[0029] (1) The grommet 3 constituting the cable 2 mounting structure 1 is provided along the circumferential direction on the outer peripheral wall 30a of the main body 30 which is fused and fixed to the sheath 21 of the cable 2, and has a fitting portion 32 that fits into a mounting hole 40 formed in the bracket 4. The fitting portion 32 has a polygonal shape in a cross section that intersects with the extension direction D1 in which the cable 2 extends. The mounting hole 40 also has a polygonal outline corresponding to the cross-sectional shape of the fitting portion 32.

[0030] This prevents the grommet 3 from rotating circumferentially D2 relative to the bracket 4 or from falling off the bracket 4 due to the swinging of the cable 2. Furthermore, the cross-sectional shape of the fitting portion 32 and the contour of the mounting hole 40 are polygonal, corresponding to the mounting angle of the cable 2. For example, the fitting portion 32 with a hexagonal cross-section and the mounting hole 40 with a hexagonal contour correspond to a mounting angle of 60°. Therefore, when attaching the cable 2 and grommet 3 to the bracket 4, the worker can easily determine that the cable 2 and grommet 3 have rotated circumferentially D2 to the desired mounting angle. As a result, the work efficiency when attaching the grommet 3 to the bracket 4 can be improved.

[0031] Here, we will describe a comparative example in which the shape of the fitting portion formed in the grommet and the shape of the mounting hole formed in the bracket differ. Figure 5 is a schematic diagram showing a cross-section of the fitting portion 101 formed in the grommet 100 of the comparative example. As shown in Figure 5, the fitting portion 101 has a circular cross-section in the plane that intersects (orthogonal or nearly orthogonal to) the extension direction D1. Note that the diameter of the fitting portion 101 is smaller than the diameter of the main body portion 102.

[0032] Figure 6 is an external view of a comparative example bracket 110 to which a grommet 100 is attached. The bracket 110 has a mounting hole 111 formed therein. The mounting hole 111 is a through hole that penetrates the bracket 110 in the extension direction D1. The mounting hole 111 is composed of a communication portion 112 and a housing portion 113. The communication portion 112 connects the housing portion 113 to the outside of the bracket 110, similar to the first embodiment described above.

[0033] The housing portion 113 has a circular outline corresponding to the circular shape of the fitting portion 101. At the point where the wall surface of the housing portion 113 and the wall surface of the communication portion 112 connect, a claw portion 114 is formed that protrudes toward the radial center.

[0034] Figure 7 is a cross-sectional view showing the mounting state of the grommet 100 and the bracket 110. As shown in Figure 7, the claw portion 114 formed in the mounting hole 111 has its tip biting into the fitting portion 101. Therefore, the claw portion 114 functions as an anti-rotation and anti-detachment mechanism for the fitting portion 101 housed in the housing portion 113.

[0035] However, as the cable 2 swings, the mating portion 101 is subjected to stress from the claw portion 114 to prevent rotation and stress to prevent detachment. As a result, the load on the part of the mating portion 101 where the claw portion 114 bites in becomes large, which may damage or break the grommet 100 and cause the grommet 100 to detach from the bracket 110.

[0036] In contrast, in this embodiment, the bracket 4 does not have a structure that prevents rotation and detachment by biting into the fitting portion 32. Therefore, according to this embodiment, rotation and detachment of the grommet 3 can be achieved without damaging the grommet 3.

[0037] <Second Embodiment> The mounting structure of the second embodiment will now be described. Hereinafter, components similar to those in the mounting structure 1 of the first embodiment will be given the same reference numerals, and the differences from the first embodiment will be described primarily. Points that are not specifically described are the same as in the first embodiment. In the second embodiment, the cross-sectional shape of the fitting portion and the contour of the mounting hole are different from the cross-sectional shape of the fitting portion 32 and the contour of the mounting hole 40 of the first embodiment. These will be described in detail below.

[0038] Figure 8 is a cross-sectional view of the grommet 3 and cable 2 of the mounting structure 1 of the second embodiment along line AA in Figure 1. Figure 9 is an external view of the bracket 4 as seen from the extension direction D1 of the cable 2. Figure 10 is a cross-sectional view of the mounting structure 1 showing the mounting state of the grommet 3 and bracket 4 as seen from the extension direction D1.

[0039] <Grommet 3> As shown in Figure 8, the main body 30 of the grommet 3 in the second embodiment has a fitting portion 50 formed with a plurality of grooves 51. Specifically, on a surface that intersects (orthogonal or nearly orthogonal to) the extension direction D1, grooves 51 are formed along the circumferential direction D2, for example, at intervals of 60° on the outer wall surface 54, which is the outer edge of the fitting portion 50.

[0040] Each groove 51 is tapered, becoming narrower towards the radial center of the cable 2. More specifically, in the groove 51, the first inclined surface 52 and the second inclined surface 53 intersect at a predetermined angle towards the radial center. In this case, the angle between the first inclined surface 52 and the second inclined surface 53 is 120° or more. That is, in a cross section intersecting (orthogonal or nearly orthogonal to) the extension direction D1, the fitting portion 50 of the second embodiment is also polygonal.

[0041] <Bracket 4> As shown in Figure 9, the bracket 4 has a mounting hole 60. The mounting hole 60 is formed by a communication portion 41 and a housing portion 61, which has a different contour from the housing portion 42 of the first embodiment. In a plane intersecting (orthogonal or nearly orthogonal to) the extension direction D1, the housing portion 61 has a contour corresponding to the cross-sectional shape of the fitting portion 50 formed in the grommet 3.

[0042] Specifically, the bracket 4 has a plurality of protrusions 62 that project radially toward the center from the inner wall surface of the housing 61. The protrusions 62 are formed along the circumferential direction D2, for example, at intervals of 60°. Each of the plurality of protrusions 62 is formed in a tapered shape, becoming narrower toward the radial center. More specifically, in the protrusions 62, the first protruding surface 63 and the second protruding surface 64 intersect at a predetermined angle toward the radial center. In this case, the angle between the first protruding surface 63 and the second protruding surface 64 is 120° or more. That is, the mounting hole 60 formed in the bracket 4 of the second embodiment also has a polygonal contour.

[0043] <Attaching grommet 3 to bracket 4> In the second embodiment, the grommet 3 is attached to the bracket 4 in the same manner as in the first embodiment. That is, the fitting portion 50 passes through the communication portion 41 of the bracket 4 and is then housed in the housing portion 61.

[0044] As shown in Figure 10, when the fitting portion 50 is housed in the housing portion 61, the protruding portion 62 of the bracket 4 is housed in the groove portion 51 formed in the fitting portion 50. That is, the first protruding surface 63 of the protruding portion 62 and the first inclined surface 52 of the groove portion 51 face each other, and the second protruding surface 64 of the protruding portion 62 and the second inclined surface 53 of the groove portion 51 face each other. Therefore, even if a rotational force is applied to the grommet 3 in accordance with the movement of the cable 2 when the cable 2 swings, the rotation of the grommet 3 in the circumferential direction D2 is suppressed by the contact between the protruding portion 62 and the groove portion 51. In other words, the fitting portion 50 and the mounting hole 60 function as anti-rotation devices for the grommet 3.

[0045] Furthermore, since the cross-sectional shape of the fitting portion 50 and the contour of the mounting hole 60 are polygonal, similar to the first embodiment, when attaching the cable 2 and grommet 3, the worker can easily determine the mounting angle of the cable 2 and grommet 3.

[0046] <Method for manufacturing grommet 3> Grommet 3 is manufactured by injection molding of synthetic resins such as ethylene propylene diene rubber (EPDM) as described above. In other words, grommet 3 is formed by pouring synthetic resin into a mold, and then removing the mold after the synthetic resin has cooled.

[0047] Figure 11 is a schematic cross-sectional view showing the structure of the mold 70. The mold 70 has a first mold 71 and a second mold 72. The second mold 72 is provided so as to be separable by moving it relative to the first mold 71 along the splitting direction D3 indicated by the arrow in Figure 11. This allows the first mold 71 and the second mold 72 to switch between a state in contact with each other and a separated state where they are separated from each other.

[0048] The mold 70 has a cavity 73 formed across the first mold 71 and the second mold 72. When the first mold 71 and the second mold 72 are in contact with each other, synthetic resin is poured into this cavity 73.

[0049] As shown in Figure 11, the contour of the cavity 73 is formed in a shape corresponding to the polygon of the fitting portion 50 formed in the grommet 3. Specifically, the inner wall surface of the cavity 73 has six mold protrusions 74 that project toward the radial center of the cavity 73. Each of the six mold protrusions 74 is tapered, becoming narrower toward the radial center. More specifically, in each of the six mold protrusions 74, the first mold protrusion surface 75 and the second mold protrusion surface 76 intersect at a predetermined angle toward the radial center. The angle between the first mold protrusion surface 75 and the second mold protrusion surface 76 is 120° or more. That is, the cross-sectional shape of the mold protrusion 74 has a shape corresponding to the cross-sectional shape of the groove portion 51 of the fitting portion 50.

[0050] When synthetic resin is poured into the cavity 73 while the first mold 71 and the second mold 72 are in contact with each other, grooves 51 are formed in the fitting portion 50 of the grommet 3 according to the shape of the mold protrusions 74. As shown in Figure 11, of the six mold protrusions 74, three mold protrusions 74a, 74b, and 74c are formed in the first mold 71. Also, of the six mold protrusions 74, three mold protrusions 74d, 74e, and 74f are formed in the second mold 72.

[0051] Of the mold protrusions 74a, 74b, and 74c formed on the first mold 71, one mold protrusion 74a formed on the side closer to the interface with the second mold 72 and the other mold protrusions 74c have portions that are parallel or substantially parallel to the division direction D3. Specifically, the first mold protrusion surface 75 of mold protrusion 74a and the second mold protrusion surface 76 of mold protrusion 74c are parallel or substantially parallel to the division direction D3. It can also be said that the first mold protrusion surface 75 of mold protrusion 74a and the second mold protrusion surface 76 of mold protrusion 74c are parallel or substantially parallel to each other.

[0052] Similarly, of the mold protrusions 74d, 74e, and 74f formed on the second mold 72, one mold protrusion 74d and the other mold protrusions 74f, which are formed on the side closer to the interface with the first mold 71, have portions that are parallel or substantially parallel to the division direction D3. That is, the first mold protrusion surface 75 of mold protrusion 74d and the second mold protrusion surface 76 of mold protrusion 74f are parallel or substantially parallel to the division direction D3. It can also be said that the first mold protrusion surface 75 of mold protrusion 74d and the second mold protrusion surface 76 of mold protrusion 74f are parallel or substantially parallel to each other.

[0053] Figure 12 schematically shows a cross-section of the mold 70 after the grommet 3 has been formed in the mold 70 and the mold 70 has been divided. After the synthetic resin poured into the cavity 73 has cooled, the second mold 72 moves along the dividing direction D3, thereby dividing the mold 70.

[0054] Because the inner wall surface of the cavity 73 has the shape described above, when dividing the mold 70, the mold projection 74 of the second mold 72 and the grommet 3 do not interfere with each other in the dividing direction D3. Similarly, when removing the grommet 3 from the first mold 71, the mold projection 74 of the first mold 71 and the grommet 3 do not interfere with each other in the dividing direction D3. As a result, even with a mold 70 in which a cavity 73 with a polygonal contour is formed, it is possible to divide the mold 70 and remove the grommet 3 after the synthetic resin has cooled.

[0055] As described above, the angle between the first mold protruding surface 75 and the second mold protruding surface 76 is 120° or more. Also, the angle between the first inclined surface 52 and the second inclined surface 53 of the groove 51 of the grommet 3 is 120° or more. In other words, the angle between the first inclined surface 52 and the second inclined surface 53 of the groove 51 is set to a value such that the mold 70 and the grommet 3 do not interfere with each other in the division direction D3 when the mold 70 is divided.

[0056] The angle between the first inclined surface 52 and the second inclined surface 53 (i.e., the angle between the first mold protruding surface 75 and the second mold protruding surface 76) can be 180 × (n-2) / n [°] or more, where n is the number of grooves 51 formed in the fitting portion 50. The grooves 51 are formed at intervals of 360 / n [°] in the circumferential direction D2. The value of n is an integer of 6 or more. However, if the number of grooves 51 increases, the angle between the first inclined surface 52 and the second inclined surface 53 increases, and the function of the fitting portion 50 as an anti-rotation mechanism decreases. For this reason, it is more preferable that the value of n is an integer between 6 and 10.

[0057] Furthermore, as described above, in order to prevent interference between the mold 70 and the grommet 3 when the mold 70 is divided, the first mold projection surface 75 of one mold projection 74 and the second mold projection surface 76 of the other mold projection 74 must be parallel or approximately parallel to the dividing direction D3. As described above, the angle between the first mold projection surface 75 and the second mold projection surface 76 is determined according to the value of n. However, when n is an odd number, the first mold projection surface 75 of one mold projection 74 and the second mold projection surface 76 of the other mold projection 74 become non-parallel to the dividing direction D3. In other words, there is a risk that the mold 70 and the grommet 3 will interfere when the mold 70 is divided. For this reason, when the grommet 3 is manufactured using the mold 70, it is even more preferable that the value of n is an even number between 6 and 10.

[0058] Figure 13 is a cross-sectional view of the grommet 3 and cable 2 in a modified example where n is 8, i.e., the number of grooves 51 is 8. In this case, the angle between the first inclined surface 52 and the second inclined surface 53 that constitute the groove 51 of the fitting portion 50 is 135° or more.

[0059] Figure 14 schematically shows a cross-section of a mold 70 used to manufacture a modified grommet 3 with eight grooves 51. In this case, eight mold protrusions 74 are provided in the cavity 73 formed in the mold 70. Of the eight mold protrusions 74, four mold protrusions 74a, 74b, 74c, and 74d are formed in the first mold 71. Also, four mold protrusions 74e, 74f, 74g, and 74h are formed in the second mold 72. In each mold protrusion 74, the angle between the first mold protrusion surface 75 and the second mold protrusion surface 76 of the mold protrusion 74 is 135° or greater.

[0060] Of the mold protrusions 74a, 74b, 74c, and 74d formed on the first mold 71, two mold protrusions 74a and 74d are formed on the side closer to the interface with the second mold 72. The first mold protrusion surface 75 of mold protrusion 74a and the second mold protrusion surface 76 of mold protrusion 74d are parallel or approximately parallel to the division direction D3. Similarly, of the mold protrusions 74e, 74f, 74g, and 74h formed on the second mold 72, two mold protrusions 74e and 74h are formed on the side closer to the interface with the first mold 71. The first mold protrusion surface 75 of mold protrusion 74e and the second mold protrusion surface 76 of mold protrusion 74h are parallel or approximately parallel to the division direction D3.

[0061] As a result, even when the value of n is 8, i.e., when a grommet 3 having 8 grooves 51 is manufactured, the mold 70 can be divided without the mold 70 and the grommet 3 interfering with each other.

[0062] According to the second embodiment described above, in addition to the effects (1) obtained by the first embodiment, the following effects can be obtained.

[0063] (2) Six or more grooves 51 are provided at regular intervals along the circumferential direction D2 on the outer wall surface 54, which is the outer edge of the fitting portion 50. In addition, multiple protrusions 62 are formed in the mounting hole 60 of the bracket 4, extending radially from the inner wall surface of the housing portion 61 toward the center. When the grommet 3 is attached to the bracket 4, the protrusions 62 formed in the housing portion 61 are accommodated in the grooves 51 formed in the fitting portion 50. As a result, when the cable 2 swings and a rotational force is applied to the grommet 3, the protrusions 62 come into contact with the grooves 51, thereby suppressing the rotation of the grommet 3 in the circumferential direction D2. In other words, the cross-sectional shape of the polygonal fitting portion 50 and the contour of the polygonal mounting hole 60 function as anti-rotation devices for the grommet 3. Furthermore, because the protrusions 62 are accommodated in the grooves 51, the grommet 3 is prevented from falling off the bracket 4.

[0064] Furthermore, the cross-sectional shape of the fitting portion 50 and the contour of the mounting hole 60 are polygonal, and the groove portion 51 and the protrusion portion 62 are provided at regular angles along the circumferential direction D2. Therefore, similar to the first embodiment, when attaching the cable 2 and grommet 3, the worker can easily determine the mounting angle of the cable 2 and grommet 3. As a result, the work efficiency when attaching the grommet 3 to the bracket 4 is improved.

[0065] (3) The groove 51 has a first inclined surface 52 and a second inclined surface 53. The angle between the first inclined surface 52 and the second inclined surface 53 is 180 × (n-2) / n [°] or more, where n is the number of grooves 51 (n is an integer of 6 or more). In addition, a plurality of mold protrusions 74 are formed in the cavity 73 formed in the mold 70 for manufacturing the grommet 3, according to the cross-sectional shape of the groove 51. The angle between the first mold protrusion surface 75 and the second mold protrusion surface 76 that form these mold protrusions 74 is also 180 × (n-2) / n [°] or more.

[0066] As a result, in the first mold 71, the first mold projection surface 75 of mold projection 74a and the second mold projection surface 76 of mold projection 74c can be formed to be parallel or substantially parallel to the division direction D3. Similarly, in the second mold 72, the first mold projection surface 75 of mold projection 74d and the second mold projection surface 76 of mold projection 74f can be formed to be parallel or substantially parallel to the division direction D3.

[0067] As a result, after the synthetic resin poured into the cavity 73 cools, when the second mold 72 moves along the splitting direction D3 and the mold 70 is split, interference between the mold protrusion 74 of the second mold 72 and the grommet 3 is prevented. Similarly, when removing the grommet 3 from the first mold 71, interference between the mold protrusion 74 of the first mold 71 and the grommet 3 is prevented. As a result, even with a mold 70 in which a cavity 73 with a polygonal contour is formed, it becomes possible to split the mold 70 and remove the grommet 3 after the synthetic resin has cooled. In other words, damage to the grommet 3 during the splitting of the mold 70 and when removing the grommet 3 from the first mold 71 is suppressed, and the deterioration of the quality of the grommet 3 is suppressed.

[0068] Although various embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications are included. Furthermore, the embodiments described above are described in detail for the purpose of explaining the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. All of these are within the scope of the present invention. Furthermore, the numerical values ​​and other figures included in the text and figures are merely examples, and using different ones will not impair the effects of the present invention.

[0069] Cable 2 is not limited to those that are attached to a vehicle, and mounting structure 1 is not limited to those that are attached to a vehicle.

[0070] The grommet 3 is not limited to a configuration in which the pivot end 31 is formed on one end of the main body 30 in the extension direction D1. The grommet 3 may have pivot end 31 at both ends of the main body 30 in the extension direction D1. Alternatively, the grommet 3 may not have pivot end 31 at all. [Explanation of Symbols]

[0071] 1 Mounting structure, 2 Cable, 3 Grommet, 4 Bracket, 21 Sheath, 30 Main body, 30a Outer wall, 32, 50 Fitting part, 40 Mounting hole, 51 Groove, 52 First inclined surface, 53 Second inclined surface, 54 Outer wall surface, 60 Mounting hole, 62 Protrusion, 63 First protrusion surface, 64 Second protrusion surface, 70 Mold, 71 First mold, 72 Second mold, 73 Cavity, 74, 74a, 74b, 74c, 74d, 74e, 74f, 74g, 74h Mold protrusion, 75 First mold protrusion surface, 76 Second mold protrusion surface, D1 Extension direction, D2 Circumferential direction, D3 Division direction

Claims

1. A grommet provided around a cable and attached to a bracket, A cylindrical main body is fused and fixed to the sheath of the cable, The main body portion comprises a fitting portion provided along the circumferential direction on the outer peripheral wall of the main body portion, which fits into a mounting hole formed in the bracket, The fitting portion is a grommet having a polygonal shape in a cross-section that intersects the direction in which the cable extends.

2. In the grommet according to claim 1, A grommet having six or more grooves provided at regular intervals along the circumferential direction on the outer edge of the fitting portion.

3. In the grommet according to claim 2, The groove portion has a first inclined surface and a second inclined surface, A grommet in which the angle between the first inclined surface and the second inclined surface is 180 × (n-2) / n [°] or greater, where n is the number of grooves (n is an integer of 6 or more).

4. A grommet is provided around the cable, The bracket comprises a mounting hole into which the grommet is attached, The grommet is, A cylindrical main body is fused and fixed to the sheath of the cable, The main body has a fitting portion provided along the circumferential direction on the outer circumferential wall that fits into the mounting hole, The fitting portion has a polygonal shape in a cross-section that intersects the direction in which the cable extends. The mounting hole has a polygonal outline corresponding to the cross-sectional shape of the fitting portion, which is a cable mounting structure.

5. A method for manufacturing a grommet comprising a cylindrical main body and a fitting portion provided along the circumferential direction on the outer peripheral wall of the main body, wherein a plurality of grooves having a first inclined surface and a second inclined surface are formed at regular intervals along the circumferential direction on the outer edge of the fitting portion, A step of injecting the grommet material into the mold, The process includes dividing the mold and removing the grommet, The mold is provided with a plurality of mold protrusions having a shape corresponding to the shape of the groove, Each of the aforementioned mold protrusions has a first mold protrusion surface and a second mold protrusion surface. A method for manufacturing a grommet, wherein the first mold projection surface of one of the mold projections and the second mold projection surface of the other mold projection are parallel to the dividing direction that divides the mold.

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