JP2011239562A - Wiring harness sheath material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheath material for a wiring harness that is provided with a bellows-like tube that easily recovers from a twisted condition or is hard to be twisted.SOLUTION: In a sheath material for a wiring harness having a bellows-like tube including ring-shaped crest parts and trough parts that are continuously alternating in the longitudinal direction, the centers of the trough and crest parts of the bellows-like tube are positioned on the same axis and the trough parts are round and have the same diameter while the crest parts have oval shapes and the crest parts that are neighboring in the longitudinal direction have long axis and short axis that are shifted by 90 degree and the size of the short axis is larger than the diameter of the trough part.

Description

  The present invention relates to an exterior material for a wire harness that is routed in a vehicle. In an exterior member having a bellows tube portion in which annular crests and valleys are alternately provided in the length direction, the shape of the bellows tube portion is improved. To increase durability.

  Conventionally, when a wire harness routed in an automobile is bent or expanded and contracted, a grommet or corrugated tube having a bellows tube portion in which annular ridges and valleys are alternately provided in the length direction is used as an exterior material. Used. Specifically, a corrugated tube or grommet provided with a bellows tube portion is suitably used for a wire harness that is routed to a back door or a side door, is stretched over the vehicle body side, and is repeatedly bent and stretched.

  As described above, the bellows tube portion has an advantage that it can be easily bent. However, since the bellows tube portion is easily bent, there is a problem that an unexpected twist is generated and the bellows tube portion is easily deformed. When twisting occurs and the twisted state continues, fatigue accumulates in the grommet made of rubber or the like, and as a result, “tear” is likely to occur. Further, in the case of a corrugated tube which is a resin molded product, there is a risk of cracking due to fatigue due to twisting. Thus, when a tear and a crack arise, there exists a problem which cannot ensure watertightness and a protective function also falls.

  With regard to the bellows tube portion of the exterior material for the wire harness, the present applicant has disclosed in Japanese Patent Laid-Open No. 10-148279 that the flexibility is good and the outer diameter of the bent portion can be reduced. An illustrated bellows tube portion 100 is provided. The bellows tube portion 100 does not match the center C <b> 1 of the peak portion 101 and the center C <b> 2 of the valley portion 102, and makes the peak portion 101 eccentric relative to the valley portion 102.

The bellows tube portion has an advantage in that the outer diameter dimension is not increased and the flexibility is good when the wire harness arranged in the automobile is bent and held at a required angle.
However, when a bellows tube part with a wire harness inserted between the door and the vehicle body is routed, the bellows tube part is easy to twist, so after twisting as the door opens and closes, It tends to be twisted without returning.

  This is because in the bellows tube portion, when a circular (perfect circle) crest having the same outer diameter is continuous, once twisting occurs, it is twisted back and it is difficult to return to the original state. In Patent Document 1, the central points of the peak and valley are decentered, but the peaks are arranged in a circle with the same outer diameter. The problem of fatigue and accumulation of tears and cracks cannot be solved.

JP 10-148279 A

  The present invention has been made in view of the above problems, and in a sheath material for a wire harness having a bellows tube portion, even if the bellows tube portion is twisted, the twist is easily returned and the bellows does not remain in a twisted state. An object of the present invention is to provide an exterior material for a wire harness provided with a pipe portion.

In order to solve the above-described problem, the present invention provides an exterior material for a wire harness having a bellows tube portion in which annular crests and troughs are alternately continued in the length direction.
The center of the valley portion and the crest portion of the bellows tube portion is located on the same axis, and the trough portion has a circular shape with the same outer diameter, while the crest portion has an elliptical outer shape and is adjacent in the length direction. The ridge portion to be provided has a major axis and a minor axis shifted by 90 degrees, and the dimension of the minor axis is larger than the diameter of the valley portion, and an exterior material for a wire harness is provided.

  As described above, the peak portion of the bellows tube portion is elliptical, and the direction of the ellipse is shifted by 90 degrees. If the crest portion of the bellows tube portion is a perfect circle with the same diameter and the crest portion of the perfect circle is continuous, it is difficult to return from the twisted state. If the ellipse's major axis direction and minor axis direction are shifted by 90 degrees, the torsional force tends to be reduced, and it becomes easier to return from the twisted state and from the untwisted state. It becomes difficult to twist.

  The sheathing material for a wire harness of the present invention having the bellows tube portion is a grommet or resin made of rubber or elastomer in which the bellows tube portion protrudes from a fixing portion attached to a through hole of a panel such as a vehicle body panel or a door panel. It is suitable as a corrugated tube made of a molded product.

In the case of the grommet, the wire harness routed to the side door or the back door of the automobile is externally mounted on the vehicle body side, and the bellows pipe portion is bridged between the door and the vehicle body to open and close the door. Accordingly, the bellows tube portion is suitably used for being twisted and untwisted.
In this type of grommet, the bellows tube portion is twisted in response to the opening operation of the door, but the twist can be reliably returned during the door closing operation. In addition, it is possible to reduce the occurrence of twist in the bellows tube portion without accompanying the opening / closing operation of the door.

In the case of the corrugated tube, the corrugated tube is suitably used for a sheath that is sheathed by a wire harness routed inside the slide door and that is bent and stretched according to the opening and closing of the slide door.
Note that the shape of the present invention can also be suitably applied to the shape of the bellows tube portion of a grommet or corrugated tube that is externally mounted on a wire harness that does not bend and extend / contract.

  As described above, in the exterior material for a wire harness of the present invention, the outer shape of the peak portion of the bellows tube portion is elliptical, and the major axis direction and the minor axis direction are shifted by 90 degrees between the adjacent peak portions. It becomes difficult to twist, and it becomes easy to be untwisted after being twisted. Therefore, the twist continues and fatigue accumulates. As a result, it is possible to prevent the bellows tube portion from being torn or cracked and to improve the reliability as the exterior material.

It is a perspective view which shows the state which wired the wire harness which attached the grommet of embodiment of this invention to the back door. The said grommet is shown, (A) is an enlarged front view, (B) is a perspective view. (A) is the sectional view on the AA line of FIG. 2 (A), (B) is sectional drawing on the BB line. (A) (B) is drawing which shows a prior art example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 to FIG. 3 show an exterior material for a wire harness made of the grommet of the first embodiment.

The grommet 1 is externally mounted on a wire harness (door harness) 4 that spans between a back panel 2 and a back door 3 of an automobile as shown in FIG.
Grommet 1 is formed of rubber or elastomer. The grommet 1 includes a fixing portion 5 to be attached to the through hole of the back door 3, a fixing portion 6 to be attached to the through hole of the back panel 2 on the vehicle body side, and pipe portions 7 and 8 continuous to the fixing portions 5 and 6, respectively. And the bellows tube part 10 arrange | positioned between this pipe part 7 and 8 is provided continuously.
The fixing portions 5 and 6 at both ends are provided with locking grooves 5a and 6a fitted to the inner peripheral edges of through holes provided in the back panel 2 and the back door 3, respectively, and tape winding tongues for fixing to the wire harness 4 The pieces 5b and 6b are provided.

The bellows tube portion 10 is provided with annular crest portions 11 and trough portions 12 alternately in the length direction.
The centers of the peaks 11 and valleys 12 are positioned on the same axis. The outer shape of the valley portion 12 is a circle (perfect circle) having the same outer diameter.
The ridges 11 have an elliptical outer shape, and the ridges 11A, 11B, 11C, 11D,..., 11N arranged in parallel in the length direction are adjacent to the ridges 11A and 11B with the major axis S1 and the minor axis S2 being 90 degrees. It is shifted. Therefore, 11 A, 11 C, 11 E,. The minor axis dimension S <b> 2 of the peak portion 11 is larger than the inner diameter of the valley portion 12.

  The wire harness 4 is inserted into the grommet 1 having the above-described shape, the grommet 1 is bridged between the back panel 2 and the back door 3, and the fixing portions 5 and 6 at both ends of the grommet 1 are connected to the back panel 2 and the back door. 3 is inserted and locked in the through hole 3 and fixed.

  When the back door 3 is lifted upward with the hinge at the upper end as a fulcrum and opened upward, the grommet 1 rotates in conjunction with the rotation of the back door 3 and the mounting positions of the fixing portions 5 and 6 are shifted in the left-right direction. Therefore, the peak portion 11 and the valley portion 12 of the bellows tube portion 10 slide and rotate with each other and twist. And since the peak part 11 of the bellows tube part 10 is made into an ellipse shape, compared with the case where it is set as a perfect circle shape, a shape changes easily and it will be in a twisted state smoothly.

  When the back door 3 is closed, the bellows tube portion 10 rotates in the direction in which the twist returns from the twisted state. At that time, since the peak portion 11 of the bellows tube portion 10 has an elliptical shape as described above, the shape is easily changed as compared with the case of a perfect circle shape, and the original twisted state is easily returned. Furthermore, since the peak part 11 has changed the adjacent peak part and the major axis direction and the minor axis direction, the force when it rotates is easy to escape, and it returns smoothly to the state which is not twisted.

  In the case where the twist does not return at the bellows tube portion 10, stress is applied to the fixing portions 5 and 6 at both ends of the grommet 1, the contact state with the back panel 2 and the back door 3 cannot be maintained, and the waterproof function is lowered. Further, if the twisted state continues, the bellows tube portion 10 is likely to be cracked or torn due to fatigue. On the other hand, the waterproof function of the grommet 1 can be enhanced if the twist is reliably returned at the bellows tube portion 10 as described above.

  The embodiment is a grommet having a bellows tube portion, but also in an exterior product for a wire harness made of a corrugated tube that is a resin molded product, the shape of the mountain portion is an elliptical shape and is adjacent in the length direction. The direction of the major axis and the minor axis of the peak may be shifted by 90 degrees. In particular, the corrugated tube is suitable for use as an exterior material for a wire harness that is repeatedly bent and stretched.

DESCRIPTION OF SYMBOLS 1 Grommet 2 Back panel 3 Back door 4 Wire harness 5, 6 Fixed part 10 Bellows tube part 11 Mountain part 12 Valley part S1 Long axis S2 Short axis

Claims (3)

In an exterior material for a wire harness having a bellows tube portion in which annular ridges and valleys are alternately continued in the length direction,
The center of the valley portion and the crest portion of the bellows tube portion is located on the same axis, and the trough portion has a circular shape with the same outer diameter, while the crest portion has an elliptical outer shape and is adjacent in the length direction. An outer covering material for a wire harness, wherein the peak portion to be shifted is 90 degrees between the major axis and the minor axis, and the minor axis dimension is larger than the diameter of the valley portion.   The wire harness that is routed to the side door or back door of the automobile is sheathed on the vehicle body side, and the bellows tube portion is bridged between the door and the vehicle body. The exterior material for a wire harness according to claim 1, wherein the portion is made of a grommet that is twisted and untwisted.   The packaging material for a wire harness according to claim 1, comprising a corrugated tube.

Images