JP5564005B2 - Detachable tow hook mounting structure - Google Patents

Description

  The present invention relates to a mounting structure for a detachable tow hook for an automobile.

  The detachable tow hook is attached to the automobile as needed during towing or transportation by ship (for tie-down), but is usually removed. A male screw is usually threaded at the detachable end of the detachable tow hook, and this is screwed onto a female screw member fixed to the vehicle body.

  Such a female screw member is generally fixed to the side member itself (see Patent Document 1), bumper reinforcement or bumper stay (see Patent Documents 2 to 6) on the axis of the side member of the vehicle body.

  However, in the structure of Patent Document 1, during the collision, the crushing of the bumper reinforcement and the bumper stay is prevented by the female screw member, and the bumper reinforcement and the bumper stay cannot contribute to energy absorption.

  On the other hand, in the case of the structures of Patent Documents 2 to 6, the bumper reinforcement and the bumper stay are crushed prior to the crushing of the side member at the time of collision, and have a role of absorbing the collision energy. It is not suitable for supporting a large traction load and traction moment applied from the traction hook.

  In addition, in the structures of Patent Documents 2 to 4, the bumper reinforcement or the bumper stay is prevented from being crushed by the female screw member, and the bumper stay is not easily crushed by the female screw member even in the structure of Patent Document 5. In the structure of Patent Document 6, a female screw member that retreats at the time of collision may damage the side member, and a relatively large opening is formed at a position through which the traction hook of the bumper reinforcement is passed. May be vulnerable.

  Further, in Patent Document 7, a hole penetrating in the front-rear direction is formed in the bumper reinforcement, a shaft portion of a bumper stay made of a tubular aluminum alloy extruded material is fitted into the hole, and a front end thereof protrudes forward from the hole. In this state, a bumper structure in which the shaft portion is expanded by electromagnetic forming and the shaft portion is fixed to the front and rear walls of the bumper reinforcement is described. However, this Patent Document 7 does not disclose the attachment structure of the removable traction hook.

  On the other hand, in Patent Document 8, a female screw member is fixed in a bumper stay in which a shaft portion is expanded by electromagnetic forming of an aluminum alloy extruded material as in Patent Document 7 and is hollow from the front end to the rear end. The tow hook mounting member is arranged at the rear end of the bumper stay and fixed to the side member. As a result, the female screw member is firmly supported, and even if the bumper reinforcement and the bumper stay are completely crushed at the time of a collision, the female screw member is not obstructed during that time, and the occurrence of uncrushed remains is prevented. . And the shaft part of the bumper stay is in close contact with the inner peripheral surface of the through hole (opening through the tow hook) formed in the bumper reinforcement, and this part is reinforced. He says he is not vulnerable to collisions, but rather is solid.

Japanese Utility Model Publication No. 4-39911 JP 2000-296742 A JP 2002-68015 A JP 2004-90709 A JP 2002-53066 A JP 2003-2136 A JP 2004-237818 A JP 2008-37220 A

  In Patent Document 8, as shown in the sectional view of FIG. 3, a ring 40 formed of hard rubber or the like is passed around the pulling hook 20, and the tip end portion 11 (bumper reinforcement 1 of the shaft portion 12 of the bumper stay 10 is placed. The position of the front wall 2 is fitted into the inner periphery of the shaft portion 12 to the tip portion 11. The inner peripheral surface of the ring 40 is in close contact with the outer periphery of the traction hook 20, while the outer peripheral surface is in close contact with the inner periphery of the shaft portion 12 of the bumper stay. Thereby, a part of the load at the time of the tie-down is supported by the bumper reinforcement 1 and the bumper stay 20 through the ring 40 to reduce the concentration of the load on the nut plate 24 and the side member 25. .

  However, in Patent Document 8, the index hook 19 is free at the tip of the bumper reinforcement 1 as shown in FIG. 2, or is supported by an elastic ring 40 such as hard rubber as shown in FIG. There is only.

  For this reason, when the load direction of the load changes depending on the road, the sea, the driving of the car or the maneuvering of the ship during towing by the towing hook, it is indicated by an arrow and a dotted index hook in FIG. As described above, it is impossible to prevent the index hook (the axis thereof) from being inclined greatly deviated from the index direction or the vehicle axial direction. When such an inclination of the index hook occurs, a bending stress is repeatedly applied to the nut plate (tow hook attaching member) 24 portion for fixing the index hook 19, fatigue characteristics are lowered, and damage is likely to occur. Cause problems.

  When the direction of the index hook shaft cannot be prevented from being shifted from the axial direction of the vehicle due to a change in the load direction during towing, aluminum that is hollow from the front end to the rear end is used due to reliability problems. It is difficult to put into practical use a mounting structure in which a detachable tow hook is passed through the shaft of an alloy bumper stay.

  The present invention has been made in view of such problems, and the object of the present invention is to attach a detachable tow hook through a shaft of an aluminum alloy bumper stay that is hollow from the front end to the rear end. It is an object of the present invention to provide a detachable traction hook mounting structure in which the axial direction of the index hook does not deviate from the axial direction of the vehicle even when the load direction during traction changes.

  To achieve the above object, the gist of the detachable tow hook mounting structure of the present invention is a detachable tow hook mounting structure in an automobile bumper, and the bumper reinforcement is hollow at a predetermined position in the vehicle width direction. It has a front wall and a rear wall with respect to the vehicle length direction, and a hole that penetrates the bumper reinforcement in the vehicle length direction is formed in the front wall and the rear wall, and the bumper reinforcement is supported from the rear side. The bumper stay is composed of a shaft portion made of a tubular aluminum alloy extruded material, and a mounting portion integrally formed or fixed to the front end and the rear end of the shaft portion, and the detachment to the mounting portion on the rear end side. It is assumed that the mounting member of the traction hook is arranged, and the bumper stay is arranged so that the shaft portion corresponds to the hole of the front wall and the rear wall of the bumper reinforcement. Each attachment portion is fixed to the bumper reinforcement and the side member, and the detachable tow hook is inserted from the front side of the bumper reinforcement through the holes of the front wall and the rear wall of the bumper reinforcement. A steel washer that is inserted into the shaft portion of the bumper stay and is removably joined to the front end mounting portion of the bumper stay or the front wall of the bumper reinforcement. In the state of being fitted into the opening, it is fixed to the traction hook mounting member, and the opening of the steel washer has an expanded portion that protrudes toward the axis of the traction hook at the periphery thereof, This expansion part is supporting the axis | shaft of the said tow hook.

  In order to prevent the index hook shaft from tilting from the axial direction of the index vehicle even when the load direction during towing is changed, which is an object of the present invention, the shaft of the tow hook is firmly fixed. It's easy to see what to do. However, this fixing method can be easily performed using a fixing jig, welding joint, mechanical joint, etc. for the fixed type where the tow hook is attached and not removed. Can be implemented.

  However, in the case of a detachable tow hook that is normally removed, it becomes difficult to implement the fixing jig, the means such as welding joint and mechanical joint, etc.

  On the other hand, in the present invention, a steel washer having an opening for fitting the shaft of the tow hook is mechanically detachably attached to the front end mounting portion of the bumper stay and / or the front wall of the bumper reinforcement. It is solved by joining. Further, the opening of the steel washer is not a mere opening, but a burring process or a flare curling process that protrudes toward the axis of the traction hook so that it can support the axis of the traction hook. Devise to have a widened part. In this way, the widened portion supports the shaft of the traction hook, thereby ensuring that the index hook shaft tilts away from the index vehicle axial direction even when the load direction during traction changes. To prevent.

  As a result, the reliability of the traction hook is increased, and it is possible to put to practical use a mounting structure in which the detachable traction hook is passed through the aluminum alloy bumper stay shaft that is hollow from the front end to the rear end.

It is a perspective view explaining the attachment structure of the detachable tow hook according to the present invention. It is sectional drawing explaining the attachment structure of the detachable tow hook which concerns on this invention. It is an enlarged view of the expansion part 32 in the opening part 31 of the steel washer 30 of FIG. It is a front view of FIG. It is a rear view of FIG. It is sectional drawing (assembly drawing) explaining another aspect of the attachment structure of the removable traction hook which concerns on this invention. It is sectional drawing (assembly drawing) explaining the attachment structure of the conventional removable traction hook.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  One embodiment of the attachment structure of the detachable tow hook according to the present invention is shown in FIGS. 1 is a perspective view (assembly view), FIG. 2 is a sectional view of FIG. 1, FIG. 3 is a view of FIG. 1 viewed from the front, and FIG. 4 is a view of FIG.

Bumper reinforcement:
In the present invention, the bumper reinforcement 1 in the automobile bumper is formed of a rectangular aluminum alloy hollow extruded shape hollow extruded shape having a mouth-shaped cross section. As for the type of aluminum alloy, tempering (heat treatment) materials such as T5, T6, and T7 of 7000 series aluminum alloys referred to in JIS to AA are widely used because they are the most excellent in strength and can be made thinner and lighter. The By the way, the cross section of the bumper reinforcement 1 is not limited to such a mouth shape as long as there is no particular problem in that a hole for penetrating the detachable tow hook described later is provided. It may have a hollow cross-sectional shape.

  1 and 2, the upper side of each figure is the front side of the vehicle body (front side), and the attachment structure of the detachable tow hook to the bumper reinforcement 1 on the front side is shown. However, the detachable tow hook may be attached to the rear side (rear side) of the vehicle body, or both the front and rear sides.

  In FIG. 2, only the right side of the vehicle body of the bumper reinforcement 1 is shown. The bumper reinforcement 1 includes a central portion 4 parallel to the vehicle body width direction and left and right inclined end portions 5 that are inclined obliquely toward the rear of the vehicle body from both sides, depending on the vehicle body design. Have. That is, the left side of FIG. 2 also has a bumper reinforcement structure similar to that of FIG.

  In FIG. 2, the detachable tow hook may be attached to the central portion 4 in the vehicle width direction of the bumper reinforcement 1. However, in terms of vehicle body design, the vehicle length (vehicle body A through-hole penetrating the bumper reinforcement 1 is provided in the front-rear direction, and a detachable tow hook is attached. FIG. 2 shows a mode in which the detachable tow hook 20 is attached to the right inclined end portion 5 of the bumper reinforcement 1.

  The bumper reinforcement 1 only needs to have a hollow cross section at a predetermined position in the vehicle width direction in order to absorb energy (impact) at the time of a vehicle body collision, and needs to have the same hollow cross sectional shape over the entire length in the vehicle width direction. There is no. For example, due to the necessity for mounting, the distal end portions of the left and right inclined end portions 5 may be subjected to crushing of the cross section.

  Among the four walls constituting the rectangular hollow cross section of the bumper reinforcement 1, the through hole 6 provided in the front wall (front side wall) 2 in the vehicle length (vehicle body front-rear) direction and the rear wall (rear side wall) 3 were provided. The through holes 7 are provided so as to correspond to each other, and the shaft 22 of the detachable tow hook 20 is a through hole through which the bumper reinforcement 1 passes. That is, as defined, the bumper reinforcement 1 has a hollow cross section at a predetermined position in the vehicle width direction, and has a front wall 2 and a rear wall 3 with respect to the vehicle length direction. It is assumed that holes 6 and 7 penetrating the bumper reinforcement 1 are formed in the (vehicle body front-rear) direction.

  Since the through holes 6 and 7 do not need to hold or clamp the shaft 22 of the detachable tow hook 20, the diameter of the through holes 6 and 7 is such that the shaft 22 of the tow hook 20 can be easily attached / detached or penetrated in the vehicle length direction. The diameter is larger than the diameter of 22.

  In addition, it can replace with an aluminum alloy hollow extrusion shape material, and can also use steel bumper reinforcement. For example, a steel plate (steel sheet material) may be welded and fixed to a steel mold having a cross-sectional hat shape, and the cross section of the bumper reinforcement may be a rectangular hollow over the entire length. Alternatively, the two groove steel materials may be faced to each other and the upper and lower walls may be overlapped and welded so that the bumper reinforcement has a rectangular hollow section over its entire length.

Bumper stay:
In the present invention, the bumper stay 10 in the automobile bumper is formed from a tubular aluminum alloy hollow extruded shape having a circular cross section. The types of aluminum alloys are excellent in strength and formability, and can be made thinner and lighter, and tempering (heat treatment) such as T5, T6, T7 of 6000 series and 7000 series aluminum alloys referred to in JIS or AA. The material is widely used. Incidentally, the cross section of the bumper stay 10 is not limited to a circular shape, an elliptical shape, or the like unless there is a particular problem in terms of formability such as electromagnetic forming or the like that allows a detachable tow hook to be described later to penetrate the hollow shaft portion. These may have other hollow cross-sectional shapes derived from circular shapes, and polygonal hollow cross-sectional shapes such as octagons.

  1 and 2, the bumper stay 10 includes a tubular shaft portion 12 and a flat mounting portion (mounting flange) 11 formed integrally with the front and rear ends of the shaft portion 12 and projecting in the outer diameter direction. The mounting flanges 11 and 13 are respectively formed with bolt holes 14 (four locations). That is, as prescribed, a bumper stay 10 that supports the bumper reinforcement 1 is attached to a shaft portion 12 made of a tubular aluminum alloy extruded material, and integrally formed or fixed to the front end and the rear end of the shaft portion 12. It shall consist of the parts 11 and 13.

  As shown in FIGS. 1 and 2, the rear end of the bumper stay 10 has a mounting flange 13, a tow hook mounting member (nut plate) 24, and a side member via a bracket 15 which is a mounting jig. 25 (front flange 26). The bracket 15 is formed of a plate having a step at the peripheral portion and the central portion, and a hole is formed in the central portion. The rear end of the shaft portion 12 of the stay is fitted (inserted) into the hole, and the pipe is expanded. Thus, the mounting bracket 15 is in pressure contact with the inner peripheral surface of the hole.

  On the other hand, the mounting flange 11 at the front end of the bumper stay 10 is formed on the rear wall (rear side wall) 3 of the bumper reinforcement 1 and on the through hole 14 provided on the rear wall (rear side wall) 3. The shaft centers of the shaft portions 12 are attached in a manner corresponding to each other. In other words, it is assumed that the through hole in the shaft portion 12 is fixed and arranged on the bumper reinforcement 1 and the side member 25 so as to correspond to the holes 6 and 7 passing through the bumper reinforcement 1. A pulling hook mounting member 24 to which a female screw member 27 is fixed is disposed on the mounting portion 13 at the rear end of the bumper stay 10.

  The bumper stay 10 having a shape as shown in FIGS. 1 and 2 is obtained by electromagnetic forming a tubular aluminum alloy hollow extruded material (the cross-sectional shape is the same in the axial direction). That is, as shown in FIG. 2, a tubular aluminum alloy extruded shape whose front end is cut obliquely in accordance with the inclination of the inclined wall 5 of the bumper reinforcement 1 and whose rear end is cut perpendicular to the axial direction to have a predetermined length. (The cross-sectional shape is the same in the axial direction.)

  More specifically, as described in Patent Document 7, a tubular aluminum alloy hollow extruded shape is surrounded by a mold having an outer shape of a bumper stay, and an electromagnetic forming coil is inserted therein. It can be formed by applying an instantaneous large current to the electromagnetic forming. The mold in the case of the bumper stay of FIGS. 1 and 2 has a flat inner surface with a concave shape corresponding to the outer shape of the drum-shaped shaft portion of the bumper stay and a flat surface corresponding to the flange portion of the bumper stay. The projecting portion in the outer diameter direction has corners R and is provided at both ends of the mold. By this electromagnetic forming, the center portion of the aluminum alloy profile is projected in the outer diameter direction, and a drum-shaped shaft portion 12 is formed on the inner peripheral surface of the mold corresponding to the outer shape of the shaft portion. Since there is no mold, the profile is expanded in the outer diameter direction, hits the surface of the protruding portion of the mold, and mounting flanges 11 and 13 are formed.

Side member:
The mounting flange 13 on the rear end side of the bumper stay 10 includes a pulling hook mounting member (nut plate) 24 to which a female screw member (nut) 27 is fixed and a side member 25 via the bracket 15 which is a mounting jig. It is attached to the (front flange 26). As the nut plate 24, an aluminum plate or a steel plate can be used as appropriate.

  As this nut 27, a pierce nut is preferably used. In addition, a weld nut can also be used. In the case of a pierce nut, the pierce nut may be driven into the center of the plate 24. In the case of a weld nut, a hole is formed in the center of the plate 24, and the center of the hole is aligned with the center of the female screw hole of the weld nut, and projection welding may be performed. Instead of the nut 27, another female screw member can be used. Bolt holes 14 are formed near the outer periphery of the nut plate 24. The side member 25 is generally formed into a rectangular cross-sectional shape by bending or welding a steel plate, and has a flange 26 protruding in the outer diameter direction at the front end, and a stud bolt 28 is erected on the front surface of the flange 26. .

Steel washer:
In the present invention, even if the load direction during towing changes, the steel hook is provided so that the index hook shaft does not tilt with respect to the axial direction of the index vehicle. The opening 31 has a widened portion 32, and supports the shaft 22 of the tow hook fitted in the open portion 31 to the widened portion 32 (inserted with some clearance). It is.

  1 and 2, this steel washer is indicated by 30. In this embodiment, since it is attached to the front surface of the bumper stay 10, it corresponds to the outer diameter and outer diameter shape of the shaft portion of the bumper stay 10 or the mounting flange 11. It has a circular (disk) shape. Then, in order to fit (insert) the shaft 22 of the tow hook, an opening 31 to an expanded portion 32 having a diameter and a peripheral shape (in this case, a circle) corresponding to the outer diameter and outer diameter shape of the shaft 22 are formed. , At its approximate center. Such a steel washer 30 can be easily manufactured by forming a steel plate as a material.

  Since the opening 31 to the expanding portion 32 can be freely inserted into or extracted from the shaft portion 22 of the traction hook, the diameter of the opening 31 or the diameter of the expanding portion 32 is the outer diameter of the shaft portion 22 of the traction hook. It is necessary to make it slightly larger than that, provide some clearance, and be movable with respect to the shaft portion 22 of the tow hook. However, if the diameter of the opening 31 or the diameter of the widened portion 32 is too large, a gap (backlash) with the shaft portion 22 of the tow hook becomes too large, and the shaft portion 22 of the tow hook can be sufficiently supported. Disappear. For this reason, when the load direction during towing changes, it is impossible to reliably prevent the index hook shaft from being inclined with respect to the index vehicle axial direction. Accordingly, the clearance (clearance) between the diameter of the opening 31 or the diameter of the expanded portion 32 and the shaft portion 22 of the traction hook is set to several mm or less (preferably about 1 to 1.5 mm).

  This steel washer 30 is subjected to an insulating sealing treatment (resin coating, resin coating) on the surface so that even if it contacts an aluminum alloy material to be bonded to a different material, no electric corrosion (corrosion) occurs due to the potential difference between them. It has been subjected. The steel washer 30 is fitted to the shaft 22 of the tow hook when the tow hook 20 is inserted from the front side of the bumper reinforcement 1, and the front end mounting portion 11 of the bumper stay 10 is fitted as shown in FIGS. 6 and / or, as will be described later with reference to FIG. 6, it is mechanically joined to the front wall 2 of the bumper reinforcement 1 in a detachable manner.

  The steel washer 30 is required to have strength and rigidity because a large load is applied by the pulling hook when the tie down is performed. In this respect, when the steel washer 30 is increased in size or thickness, the weight reduction due to the aluminum alloy formation of the bumper reinforcement 1 and the bumper stay 10 is sacrificed. Therefore, high strength steel such as high tensile steel should be used. Is preferred. In this respect, on the premise that a high strength steel material (steel plate) such as high tension is used as a material, the thickness of the steel washer 30 is preferably about 0.8 to 2.0 mm.

Expanded steel washer:
Here, the opening part 31 of the steel washer 30 has an expanded part 32 projecting toward the shaft 22 of the traction hook at the periphery thereof, and this expanded part 32 provides a slight clearance between the shaft 22 of the traction hook. Have and support. This widened portion 32 becomes an engaging portion of a fixed length extending in the axial direction of the traction hook shaft 22 with the traction hook shaft 22, and the index is changed when the load direction during traction is changed. The hook shaft is reliably prevented from being inclined with respect to the axial direction of the indexing vehicle.

  Without this widened portion 32, the thickness of the washer at the peripheral edge of the opening 31 (only the preferred thickness 0.8 to 2.0 mm of the steel washer 30 extends in the axial direction of the shaft 22 of the tow hook). The engagement length is shortened and the shaft portion 22 of the tow hook cannot be sufficiently supported, so that the index hook shaft is inclined with respect to the index vehicle axial direction when the load direction during towing is changed. On the other hand, when the wall thickness of the steel washer 30 is increased in order to increase the engagement length, the weight reduction due to the aluminum alloy of the bumper reinforcement 1 and the bumper stay 10 is sacrificed. Become.

  In order for this widened portion 32 to be a support portion (engagement portion) of a certain length extending in the axial direction of the shaft 22 of the tow hook with the shaft 22 of the tow hook, an opening of the steel washer 30 is used. The expanded portion 32 in the portion 31 is preferably a folded portion 33 provided by burring when the opening 31 is formed, which is partially enlarged and shown in FIG. Moreover, it is preferable to make it the folding | returning part 34 provided by the flare curl process at the time of this opening part 31 formation partially shown in FIG.3 (b). According to such a process, the opening part 31 and the expansion part 32 can be easily provided simultaneously with the shaping | molding of the washer from a steel plate raw material (by one shaping | molding).

  In the mode of FIGS. 1 and 2, the bending (curling) direction, which is the direction of the expanded portion 32, is the upward direction in the drawing, that is, the direction toward the front side of the vehicle body. However, depending on the mounting structure of the bumper stay 10 to the bumper reinforcement 1, the bending direction that is the direction of the expanded portion 32 may be the downward direction of the drawing, that is, the direction toward the rear side of the vehicle body. There is no difference in 20 support effects. However, as will be described later, as shown in FIG. 6, if the bending direction, which is the direction of the expanding portion 32, is the lower side of the drawing, that is, the direction toward the rear side of the vehicle body, Since the widened portion 32 facing (curled) serves as a baffle plate, there is an advantage that the towing hook 20 can be prevented from penetrating.

  The steel washer 30 having such an expanded portion 32 has a rear wall of the bumper reinforcement 1 by means of stud bolts 28 (four in the embodiment of FIGS. 1 and 2) after the shaft portion 22 of the tow hook is fitted. 3 and the mounting flange 11 of the stay 10 and the bolt hole 8 provided in the rear wall 3 and the bolt hole (14) of the mounting flange 11 are preferably detachably and integrally joined. When the bumper reinforcement 1 is an aluminum alloy extruded material, the rear wall 3 of the bumper reinforcement 1 and the steel washer 30 are joined with different materials. Therefore, in order to prevent electrolytic corrosion, the washer and the extrusion are extruded as necessary. A sealing material or the like may be applied between the materials. Further, the steel washer 30 is mechanically joined in this manner so that it can be attached / detached in accordance with the attachment / detachment of the traction hook 20, and is not joined such as welding.

  By providing the steel washer 30 having such an expanded portion 32, the inner peripheral surface of the expanded portion 32 is in close contact with the outer periphery of the traction hook shaft portion 22, and thus the load is reduced during tie-down. A part is supported by the bumper reinforcement 1 and the bumper stay 10 via the steel washer 30. For this reason, even when a load during towing is applied to the towing hook at the time of tie-down or the like, it is possible to prevent the index hook shaft from being greatly inclined and displaced from the axis of the indexing vehicle. As a result, there is no problem that the attaching portion of the index hook is damaged, or the stay or the bumper reinforcement opening or the peripheral portion of the bumper that penetrates the shaft of the index hook is damaged.

Removable tow hook:
The detachable tow hook 20 itself used in the present invention may have a known or general-purpose structure that is detachable. That is, as shown in FIGS. 1 and 2, a ring-shaped head portion 21, a long shaft portion 22 integrally connected to the ring-shaped head portion 21, and a fixing male screw portion 23 formed at the rear end (or front end) of the shaft portion. Consists of.

Detachable tow hook mounting structure:
1 and 2, how to attach and detach the detachable tow hook 20 to the bumper structure (bumper reinforcement 1 and bumper stay 10) and the steel washer 30 will be described.

  When attaching the detachable tow hook 20, the stud bolt 28 is passed through the bolt hole 14 of the nut plate 24 and overlapped with the front end flange 26 of the side member 25. Then, the bolt hole 14 of the mounting flange 13 on the rear end side of the bumper stay 10 is passed through the stud bolt 28, the mounting flange 13 is overlaid on the nut plate 24, and fastened with the nut on the head of the stud bolt 28.

  When the detachable tow hook 20 is used, such as when towing or transporting by ship, it is inserted into the shaft portion 12 from the front side of the bumper stay 10, and the male screw portion 23 formed at the tip is screwed into the nut 27 and fixed. That is, from the front side of the bumper reinforcement 1, the tow hook 20 is inserted into the shaft portion 12 of the bumper stay 10 through the holes 6 and 7 that penetrate the bumper reinforcement 1 and the opening 31 of the steel washer 30. The male threaded portion 23 of the traction hook 20 is screwed into a traction hook mounting member (nut plate) 24 to which a female thread member (nut) 27 is fixed. At this time, the steel washer 30 is also joined to the rear wall 3 of the bumper reinforcement 1 through the bolt hole provided in the rear wall 3 with the stud bolt 28 after the shaft portion 22 of the tow hook is fitted. .

  In this example, the nut plate 24 is simply sandwiched and fixed between the mounting flange 13 of the bumper stay 10 and the front flange 26 of the side member 25, but the nut plate 24 is fixed to the front flange 26 of the side member 25, for example, as a spot. It can also be fixed by welding. Alternatively, the nut plate 24 can be overlapped with the mounting flange 13 of the bumper stay 10 and both can be fixed in advance by spot welding, self-piercing rivets or the like. In the latter case, the bumper reinforcement 1, the bumper stay 10, and the nut plate 24 can be handled as one bumper structure 3, and assembly work is facilitated. Further, in this example, the nut 27 is disposed on the rear side of the nut plate 24 and is located in the side member 25, but may be disposed on the front side of the nut plate 24.

  In the embodiment of FIGS. 1 and 2 having such a configuration, the stay 10, the steel washer 30, and the reinforcement 1 can be fixed together, so that it is possible to save time and labor for providing an extra joint. Further, a support for supporting the index hook 20 can be separately attached to the front surface of the reinforce 1, and the base side (side member 25 side) of the stay 10 and the front end side of the stay 10 (the rear wall 3 of the reinforce 1) Between the front wall 2 of the reinforce 1, it is possible to fix the hook more stably.

Another aspect of the detachable tow hook mounting structure:
FIG. 6 shows another embodiment of the attachment structure of the detachable tow hook according to the present invention. FIG. 6 shows a mode in which the front half of the shaft portion 12 of the bumper stay 10 is fitted in the holes 6 and 7 (in the hollow space) of the bumper reinforcement 1 in the bumper structure.

  6, the bumper stay 10 is formed of a tubular aluminum alloy extruded material, and is the same as FIGS. 1 and 2. The shaft portion 12 and the attachment integrally formed on the front and rear ends of the shaft portion 12 are the same. Parts (mounting flanges) 11 and 13. On the other hand, the front half of the shaft portion 12 is fitted into the through holes 6 and 7 of the bumper reinforcement 1, and the mounting flange 11 protrudes from the front wall 2 in the outer diameter direction. The front half of the drum-shaped shaft portion 12 is in pressure contact with the front wall surface 2 and the rear wall surface 3 which are the inner peripheral surfaces of the through holes 6 and 7 of the bumper reinforcement 1.

  Such a structure of the bumper stay 10 can also be manufactured by electromagnetic forming. That is, the tubular aluminum alloy extruded material having a predetermined length by cutting the front end obliquely in accordance with the inclination of the inclined wall 5 of the bumper reinforcement 1 and cutting the rear end perpendicularly to the axial direction is used as the bumper reinforcement 1. Are inserted into the through holes 6 and 7 so that their front ends slightly protrude from the front wall 2. The portion protruding rearward from the rear wall 3 is surrounded by the mold as described above except for the rear end portion. Then, it can be formed by inserting an electromagnetic forming coil inside the tubular extruded material and applying an instantaneous large current to the coil to perform electromagnetic forming.

  That is, by this electromagnetic forming, the portion of the aluminum alloy extruded material that protrudes rearward from the rear wall 3 is formed in the manner described above, is formed into its drum shape by hitting the inner peripheral surface of the mold, and the rear end is The mounting flange 13 is formed by expanding in the outer diameter direction and hitting the end face of the mold.

  In addition, the front half of the aluminum alloy extruded material in the bumper reinforcement 1 is also expanded outwardly, and is in close contact with the inner peripheral surfaces of the through holes 6 and 7 of the front wall 2 and the rear wall 3 of the bumper reinforcement 1. The portion protruding from the wall 2 expands in the outer diameter direction, and an expanded portion (mounting flange) 11 is formed. At this time, between the front wall 2 and the rear wall 3, the aluminum alloy extruded material projects in the outer diameter direction, and a shaft portion 12 projecting in a drum shape is formed. As described above, the shaft portion 12 (front portion) in which the shaft portion 12 of the bumper stay 10 is in pressure contact with the inner peripheral surfaces of the front wall 2, the rear wall 3, and the through holes 6 and 7 and the front wall 2 projects from the mounting flange 11. A bumper structure in which the bumper stay 10 is firmly fixed to the bumper reinforcement 1 is formed. The

  In such an embodiment, the joining position of the steel washer 30 having the expanded portion 32 is different from that in FIGS. It is detachably joined to the front side (outside) of the wall 2. Also in this case, it is preferable that the steel washer 30 is joined to the front wall 2 of the bumper reinforcement 1 by the blind rivet 29 as shown in FIGS.

  Further, in the embodiment of FIG. 6, unlike the embodiments of FIGS. 1 and 2, the bending direction, which is the direction of the expanded portion 32, is the downward direction of the drawing, that is, the direction toward the rear side of the vehicle body. As described above, this is to prevent the traction hook 20 from penetrating at the time of a vehicle collision.

  Further, in this aspect, since the steel washer 30 is attached to the front surface of the front wall 3 of the bumper reinforcement 1, the steel washer 30 includes the through hole 6 of the front wall 3 and the outside of the shaft portion of the bumper stay 10 or the mounting flange 11. It has a circular (disk) shape corresponding to the diameter and outer diameter shape. And in order to insert the axis | shaft 22 of a tow hook, it has the opening part 31 which has a diameter and a periphery shape (in this case circular) corresponding to the outer diameter and outer-diameter shape of this axis | shaft 22 in the approximate center.

  According to the present invention, in a mounting structure in which a removable traction hook is passed through an aluminum alloy bumper stay shaft that is hollow from the front end to the rear end, when the load direction during traction changes, the index hook shaft It is possible to provide a detachable tow hook mounting structure that reliably prevents the index vehicle from being inclined with respect to the axial direction of the indexing vehicle. For this reason, it is suitable for a detachable tow hook that is attached to an automobile as required when towing or transporting an automobile by ship.

1: bumper reinforcement, 2: front wall, 3: rear wall, 4: central portion, 5: inclined end portion, 6, 7: through hole, 10: stay, 12: shaft portion, 11, 13: mounting portion (flange) ), 14: bolt hole, 15: bracket, 20: detachable tow hook, 24: nut plate, 25: side member, 26: front end flange, 27: female screw member, 28: stud bolt, 29: blind rivet

Claims (3)

  A mounting structure for a detachable tow hook in an automobile bumper, wherein the bumper reinforcement has a hollow cross section at a predetermined position in the vehicle width direction, and has a front wall and a rear wall with respect to the vehicle length direction. On the other hand, a hole penetrating the bumper reinforcement in the vehicle length direction is formed, and a bumper stay for supporting the bumper reinforcement from the rear side is provided with a shaft portion made of a tubular aluminum alloy extruded material and a front end of the shaft portion. And an attachment part integrally formed or fixed to the rear end, and the attachment member of the detachable tow hook is disposed on the attachment part on the rear end side. The bumper stay is connected to the shaft part. Is fixed to the bumper reinforcement and the side member at each of the mounting portions so as to correspond to the holes in the front wall and the rear wall of the bumper reinforcement. Then, the detachable tow hook is inserted into the bumper stay shaft from the front side of the bumper reinforcement through the holes of the front wall and the rear wall of the bumper reinforcement. With the shaft of the detachable tow hook fitted into the opening of the steel washer that is detachably joined to the front end mounting portion of the bumper stay or the front wall of the bumper reinforcement, The opening portion of the steel washer has a widened portion projecting toward the shaft of the traction hook at the periphery thereof, and the widened portion supports the shaft of the traction hook. A detachable tow hook mounting structure characterized by that.   The attachment structure of the detachable traction hook according to claim 1, wherein the widened portion in the opening portion of the steel washer is provided by burring processing or flare curling processing at the time of forming the opening portion.   The attachment / detachment according to claim 1 or 2, wherein the front and rear attachment portions of the shaft portion of the bumper stay are integrally expanded with the shaft portion by electromagnetically forming the tubular aluminum alloy extruded material. -Type tow hook mounting structure.