JP2011168077A - Towing hook mounting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To compatibly achieve towing strength and crushing property, regardless of low cost and light weight, regarding a towing hook mounting structure freely attaching/detaching a towing hook to/from a towing hook mounting member at an end part of a vehicle body by screwing. <P>SOLUTION: The towing hook mounting member 18 for attaching/detaching the towing hook 22 to/from an external part of the vehicle body is fixed to a bumper reinforce side wall surface 12-1 of a crash box 12, and is directly non-fixed to a side member side. A steel wire 30 connects the towing hook mounting member 18 to the side member side. The steel wire 30 transmits tensile load by the towing hook 22 to the side member side but is free in a collision direction. When the bumper reinforce 14 and the crash box 12 are crushed during a collision, the towing hook mounting member 18 can be retreated via an escape hole 28 on the side member side. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a traction hook attachment structure in which a traction hook is detachably attached to a traction hook attachment member at the end of a vehicle body.

  As a tow hook attaching structure that can be freely attached and detached by a screw, a structure in which the tow hook side is a male screw and is attached to and detached from the female screw portion of the tow hook attaching member on the vehicle body side is common. The tow hook is attached from the front or rear of the vehicle body, but at the front or rear of the vehicle body, bumper reinforcements and crash boxes are provided to protect the side members that are the skeleton members of the vehicle body by being crushed during a collision. Yes. On the other hand, it is necessary to receive the tensile force applied when towing, but the strength of the tow hook mounting member is insufficient with only the bumper reinforcement or the crash box, so that the side member is involved in the mounting of the tow hook mounting member. For example, a structure in which a tow hook mounting member is mounted across a crash box and a side member side member (Patent Document 1), a bumper reinforcement or a crash box is passed, and the tow hook mounting member is fastened to the side member. (Patent Documents 2 and 3).

JP 2003-2136 A JP 2009-292175 A JP 2008-37220 A

  In Patent Document 1, the tow hook mounting member has a structure in which it is mounted between the crash box and the side member side member, and the pulling force at the time of towing is received by the side member side member. Since it is free on the side member side, the cushioning function by crushing the crash box is not impaired. However, the tow hook mounting member is long, which is disadvantageous in terms of component cost and weight. In addition, the tow hook mounting member can pass through the opening of the member on the side member side for the input from the front, but the crush box smooths because it moves like the opening edge for the oblique input. This may hinder proper crushing and hinder efficient energy absorption.

  In Patent Documents 2 and 3, the traction hook mounting member is freely inserted through the bumper reinforcement and the crash box, and is fixed to the member on the side member side. There is no risk of hindering the expected energy absorption because there is no hindrance, but in order to attach the traction hook, the screw part must be completely inserted through the bumper reinforcement and the crash box. The hook becomes very long, which is disadvantageous in terms of cost and weight.

  In addition, as a general traction hook mounting member mounting structure, there is also a structure that connects to the front wall of the crash box and a reinforcing plate in the middle of the front and rear walls, but in this case, all input during towing is handled by the crash box Therefore, the strength of the crash box needs to be sufficient with respect to the traction strength. On the other hand, from the buffer function at the time of collision, it is necessary to absorb energy by crushing the crash box, and the crash box needs to have a structure that is reasonably fragile. It is necessary to reinforce the plate thickness of the energy absorption part of the crash box (upper and lower left and right walls connecting the front and rear walls) to maintain traction strength, increase the plate thickness, and adopt materials with excellent strength characteristics is there. On the other hand, from the energy absorption function at the time of collision, since it is necessary to crush the crash box before the side member, it is necessary to devise measures to make the reinforced left and right walls easy to break. This leads to an increase in the price image of the material, the number of processing steps, and an increase in weight. In short, it is essential to harmonize the conflicting requirements between the required strength for traction and the energy absorption at the time of collision, and it is inevitable that the cost will increase and the weight will increase.

  The present invention has been made in view of the above problems, and an object thereof is to achieve both traction strength and crushability in spite of low cost and light weight.

  According to the present invention, the crash box at the ends of the left and right side members on both sides of the vehicle body, the bumper reinforcement extending in the vehicle width direction and disposed between the crash boxes, and the traction hook are detachably screwed from the outside of the vehicle body. It is fixed to the side wall of the bumper reinforcement of the crash box, but the traction hook mounting member that is not directly fixed to the side member side part and the traction hook mounting member are connected to the side member side to There is provided a tow hook mounting structure including a string-like member that is highly rigid in the pulling direction by the hook but low in the collision direction.

  The string-like member can be made of steel wire, and the side wall surface of the side member facing the traction hook attachment member can retract the traction hook attachment member not only in the front direction but also in an oblique direction when the crash box is crushed during a collision. In addition, a clearance hole having a size large enough to be allowed can be formed.

  The traction hook mounting member is connected to the side member side by a string member having high rigidity in the pulling direction by a traction hook such as a steel wire (piano wire) but a low rigidity in the collision direction. Since the member transmits traction force to the side member side and is free at the time of collision, it does not become a resistance against crushing of the bumper reinforcement and the crash box, so that both traction strength and crushability can be achieved.

  The tow hook mounting member is fixed to the bumper reinforcement side wall surface of the crash box, but is not fixed to the side member side portion. That's enough, and cost and weight can be reduced.

  The escape hole formed on the side wall of the side member facing the traction hook mounting member allows the traction hook mounting member to retract not only in the front direction but also in the diagonal direction when crushing the box. In contrast, the expected crushing function can be secured.

FIG. 1 shows a structure for attaching a tow hook according to the present invention, and shows an attachment portion with a side member from a bumper reinforcement through a crash box in a longitudinal section of the vehicle body. FIG. 2 is a view showing an example of a steel wire fastening structure in the present invention. FIG. 1 is a view in the direction of arrow III in FIG.

  Hereinafter, the embodiment of the present invention will be described with respect to the case where the tow hook is attached to the front portion of the vehicle body, but the present invention can be similarly applied to the case where the tow hook is attached to the rear portion of the vehicle body. In FIG. 1, reference numeral 10 denotes a side member that is a skeleton member of a vehicle body, which is made of a steel material having a rectangular cylindrical cross section, and is provided in a pair in the width direction of the vehicle body (the direction orthogonal to the plane of the drawing). A crash box (also referred to as a bumper stay) 12 is attached to the front end of the side member 10. Although the crash box 12 is made of steel, it can be preferentially crushed in the event of a collision by setting the wall thickness appropriately. This prevents the side member 10 from being suddenly subjected to a large input, thereby preventing the side member 10 from collapsing. 10 is for protecting. Although it has a rectangular cross-section in the width direction of the crash box, it is formed in a somewhat expanded cylindrical shape in the longitudinal direction, and then the wall surface 12-1 is in contact with the front wall surface 10-1 of the side member 10, These opposing wall surfaces 12-1 and 10-1 are fastened by bolts and nuts (not shown). A bumper reinforcement 14 is disposed between the pair of side members 10 in the vehicle body width direction (the direction orthogonal to the paper surface) so as to extend in the vehicle body width direction. The bumper reinforcement 14 is made of aluminum or a tubular material having a steel material rectangular cross section. The rear wall surface 14-1 of the bumper reinforcement 14 and the front wall surface 12-2 of the crash box 12 are brought into contact with each other, and these opposed wall surfaces 14-1, 12-2 are fastened by bolts and nuts (not shown). A bumper fascia 16 made of a plastic material is located in front of the bumper reinforcement 14.

  The tow hook mounting member 18 is made of a solid steel material having a circular cross section, and a reinforcing plate 20 (crash box) disposed at some distance inside the front wall surface 12-2 and the front wall surface 12-2 of the crash box 12. 12 is welded and fixed to welded portion W1). The tow hook mounting member 18 is fixed to the front wall surface 12-2 of the crash box 12 and the reinforcing plate 20 by welding, and the welded portion is indicated by W2. The tow hook mounting member 18 is not fixed (free) to the rear wall surface 12-1 of the crash box 12 and the front wall surface 10-1 of the side member 10 which are members on the side member side. The front end of the tow hook mounting member 18 protrudes into the bumper reinforcement 14 through the flaw hole 14A of the rear wall 14-1 of the bumper reinforcement 14, but the amount of protrusion is small, and the front wall of the opposing bumper reinforcement 14 is 14-2, and the rear end of the traction hook mounting member 18 is also largely separated from the rear wall surface 12-1 of the opposing crash box 12, and the traction hook mounting member 18 has its length. Is significantly shortened. A traction hook attachment hole 18A is formed from the front end side of the traction hook attachment member 18, a female screw is cut in the traction hook attachment hole 18A, and a traction hook 22 having a male screw formed at the end can be screwed and attached from the outside. In other words, the front wall surface 14-2 of the bumper fascia 16 and the bumper reinforcement 14 are formed with tow hook insertion holes 24 and 26 that are sufficiently larger than the outer diameter of the tow hook 22, and the tow end of the tow hook 22 is pulled by the tow during pulling. The hook is inserted into the pulling hook mounting hole 18A through the hook insertion holes 24 and 26. Therefore, as for the length of the traction hook mounting member 18, the traction hook mounting member 18 can be mounted on the front end side and can be welded to the reinforcing plate 20 on the rear end side. It can be greatly shortened. Further, escape holes 28 are formed in the rear wall surface 12-1 of the crash box 12 and the front wall surface 10-1 of the side member 10 (side member side portion of the present invention) opposed to the rear end of the pulling hook mounting member 18. The hole 28 is large enough to allow the retracting of the tow hook mounting member not only in the front direction but also in the oblique direction at the time of a collision (approximately twice or more than the tow hook mounting member 18).

  According to this invention, the steel wire 30 (string-like member of this invention) such as a piano wire is provided to connect the tow hook attaching member to the side member side. The string-like member such as the steel wire 30 has sufficient strength to transmit the tension by the traction hook 22 to the member on the side member side, but has no flexibility in the collision direction and does not transmit input. . The steel wire 30 is attached to the rear wall surface 12-1 of the crash box 12 or the front wall surface 10-1 of the side member 10 (side member side portion of the present invention) in the vicinity of the rear end surface of the pulling hook mounting member 18 and the inner periphery of the escape hole 28. Although not specified as a connecting means, for example, as shown in FIGS. 2 and 3, the end 30-1 of the steel wire 30 can be formed in a hook shape and fastened to the opposing surface with bolts and nuts. . As long as welding is possible, welding may be used, and any method that can be attached to the opposing surface with a required strength can be used. In some cases, welding can also be used. Further, instead of the steel wire, a string-like material having high rigidity in the pulling direction of a narrow steel strip or the like but low rigidity (flexible) in the collision direction can be employed.

  At the time of towing, the tow hook 22 is screwed to the tow hook attaching member 18 through the tow hook insertion holes 24 and 26 of the bumper fascia 16 and the bumper reinforcement 14. The tow hook attaching member 18 is connected to the front wall 12-2 of the crash box 12 and is connected to the rear wall 12-2 of the crash box 12 (or the front wall surface 10-1 of the side member 10) by a steel wire 30. Therefore, the tensile force due to traction is transmitted to the side member 10 via both the crash box 12 and the steel wire 30. That is, the crash box 12 and the steel wire 30 are assigned to transmit the tensile force, and a necessary traction force can be obtained.

  Normally, the tow hook 22 is in a removed state. In the frontal collision, the bumper reinforcement is first crushed by the collision with the opponent, and the tow hook mounting member 18 is pushed by the crushed bumper reinforcement. Since the steel wire 30 is not rigid in the crushing direction, only the crash box 12 receives input, and the crash box 12 is crushed. However, as long as the crush box 12 is crushed, the side member 10 is not subjected to collision input. It is interrupted | blocked and a side member can be protected. As the crash box 12 is crushed by the collision load, the tow hook mounting member 18 moves backward, but the crash is caused by the escape hole 28 on the rear wall surface 12-1 of the crash box 12 and the front wall surface 10-1 of the side member 10. The tow hook mounting member 18 can be retracted as indicated by phantom line 18 ′ until the box 12 is completely crushed. The state of the steel wire 30 at this time is indicated by an imaginary line 30 ′. Since the escape hole 28 has a sufficient size, it does not hit the wall surface against not only a frontal collision but also an oblique collision, and the retracting of the tow hook mounting member 18 is allowed to ensure the desired crushing characteristics. it can.

DESCRIPTION OF SYMBOLS 10 ... Side member 12 ... Crash box 14 ... Bumper reinforcement 16 ... Bumper fascia 18 ... Traction hook attachment member 20 ... Reinforcement plate 22 ... Traction hook
24, 26 ... Tow hook insertion hole 28 ... Escape hole 30 ... Steel wire (string-like member of the present invention)

Claims (3)

  The crash box at the ends of the left and right side members on both sides of the vehicle body, the bumper reinforcement that extends in the vehicle body width direction and is arranged between the crash boxes, and the tow hook are detachably screwed from outside the vehicle body, It is fixed to the side wall of the bumper reinforcement, but a non-fixed traction hook attachment member and a traction hook attachment member are connected to the side member side on the side member side portion. A tow hook mounting structure having a string member having high rigidity but low rigidity in the collision direction.   2. The tow hook mounting structure according to claim 1, wherein the string-like member is made of a steel wire.   In the first or second aspect of the present invention, the side wall surface of the side member facing the traction hook mounting member is sufficient to allow the traction hook mounting member to be retracted not only in the front direction but also in an oblique direction when the crash box is crushed during a collision. A tow hook mounting structure with an escape hole of a large size.

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