Vehicle fenders – Buffer or bumper type – Bumper having impact force absorbing means directly...
Reexamination Certificate
2004-02-04
2004-10-12
Pape, Joseph D. (Department: 3612)
Vehicle fenders
Buffer or bumper type
Bumper having impact force absorbing means directly...
C188S371000
Reexamination Certificate
active
06802548
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a shock absorber adapted to support a bumper reinforcement member on a body member of a vehicle.
2. Description of the Related Art
A shock absorber adapted to absorb an impact exerted on a bumper reinforcement member is used as a member for supporting the bumper reinforcement member on a body member. When the bumper reinforcement member is bent in a projecting state frontward in the length direction of the vehicle, an impact received by the bumper reinforcement member is exerted on the shock absorber in the diagonal direction thereof to cause the shock absorber to be inclined. When the shock absorber is of the type which absorbs impact energy owing to the plastic deformation thereof, the impact energy cannot be absorbed satisfactorily due to an inclination of the shock absorber.
Regarding this point, a shock absorber (Halteglied) disclosed in the German Patent No. 3711692 is joined to a bumper reinforcing member (Sto&bgr;stange) with a predetermined degree of freedom provided in a horizontal plane but a general construction of the shock absorber becomes complicated. In view of this, a bumper reinforcement member of the invention disclosed in JP-A-2001-158312 is provided with an engagement portion, which is engaged with an outer end portion of a shock absorber (or a shock absorbing member) when a collision of a vehicle occurs in which the bumper reinforcement is displaced in the length direction of the vehicle, for the purpose of preventing a cost increase caused by the complication of the general construction of the shock absorber, and eliminating a scatter of a shock absorbing performance occurring due to, especially, an inclining movement of the shock absorber in the outward direction of the vehicle. Furthermore, a flat plate type bumper stay is laid between the bumper reinforcement and a body member so that the bumper stay holds the shock absorber (or the shock absorbing member) therebetween.
Although the construction of the invention disclosed in JP-A-2001-158312 is certainly simple as compared with that of the invention disclosed in the German Patent No. 3711692, the impact energy is also absorbed in the flat plate type bumper stay the shock absorbing performance of which is hard to predict, so that a new problem arises, i.e., a stable shock absorbing performance is difficult to be obtained. However, when the bumper stay is not provided, there is the possibility that an outer end portion of the'shock absorber (or the shock absorbing member) which is distant from the engagement portion provided on the bumper reinforcement be not engaged well with the engagement portion. When the outer end portion of the shock absorber is not engaged well with the engagement portion of the bumper reinforcing member, the inclining of the shock absorber necessarily occurs.
The shock absorber disclosed in JP-A-2001-158312 is provided with a bead which permits the bumper stay to be bent so that the bumper stay does not disturb the shock absorber (shock absorbing member) from absorbing an impact. In this case, however, another problem arises in that the bumper stay flares the bumper reinforcement in the vertical direction. Especially, in the bumper reinforcement of a cross-sectionally opened structure disclosed as an example in JP-A-2001-158312, it may suddenly decrease section modulus of the bumper reinforcement opened vertically.
Therefore, a shock absorber capable of displaying a necessary and sufficient shock absorbing performance without being inclined even when the axial direction of the shock absorber is inclined outward with respect to the width direction of a vehicle and crosses the bumper reinforcing member at the right angles thereto.
SUMMARY OF THE INVENTION
The shock absorber according to the present invention is adapted to support a bumper reinforcing member of a vehicle and absorb by the plastic deformation of the shock absorber an impact exerted on the bumper reinforcing member, the shock absorber comprising a first collapsible shock absorbing part, and a second shock absorbing part to be compressed in the axial direction thereof inclined outward in the width direction of the vehicle, the first shock absorbing part having a structure of a basin-like truncated conical shape and including a skirt-shaped side surface, a top surface surrounded by a smaller-diameter-side circumferential edge of the side surface, an annular flange surface projecting from a larger-diameter-side circumferential edge of the side surface in the radially outward direction, and a bead integrally formed on the side surface in connection between the larger-diameter-side circumferential edge and the smaller-diameter-side circumferential edge, whereby the shock absorber has a function of aligning a direction in which the impact exerted on the bumper reinforcing member with the axial direction of the second-shock absorbing part while absorbing the same impact, and the second shock absorbing part having a function of absorbing an impact transmitted from the first shock absorbing part.
The first shock absorbing part may have a structure of a basin-like truncated pyramid shape, and preferably a structure of a basin-like truncated conical shape. When the first shock absorbing part has a polyhedral conical shape or a truncated conical shape, a collapse of the side surface except a bead-formed part thereof becomes substantially uniform in the circumferential direction, so that a designed shock absorbing performance can be displayed. In this first shock absorbing part, the top surface is brought into contact with a front end of the second shock absorbing part with the top surface faced rearward with respect to the length direction of a vehicle, or the flange surface is brought into contact with the front end of the second shock absorbing part with the top surface faced frontward with respect to the length direction of the vehicle.
The second shock absorbing part serves the purpose as long as this shock absorbing part is compressed axially and absorbs an impact. The second shock absorbing part may be of a cylindrical structure, and preferably of a multistage tubular structure in which a smaller-diameter tube portion and a larger-diameter tube portion formed by partially reducing or partially increasing the diameter of a straight tube, and which are connected together via a stepped portion in which boundary regions of the smaller-diameter and larger-diameter tube portions are folded back into each other to put these tube sections in a previously absorbed state. In this embodiment, the first shock absorbing part is formed by bringing the top surface thereof into contact with a front end of the smaller-diameter tube portion of the second shock absorbing part with the top surface faced rearward with respect to the length direction of a vehicle, or by bringing the annular flange surface thereof into contact with the front end of the smaller-diameter tube portion of the second shock absorbing part with the top surface faced forward with respect to the length direction of the vehicle.
In the shock absorber according to the present invention, a shock transmission direction is corrected by a collapse of the first shock absorbing part, and the inclination of the second shock absorbing part is thereby prevented. Thus, the second shock absorbing part being collapsed in the initial inclined axial direction. For example, when the bumper reinforcing member is bent forward in a projecting state in the length direction of the vehicle, a shock causes the bumper reinforcing member to be deformed so that the radius of bend thereof becomes smaller, and the deformation of this bumper reinforcing member gives the second shock absorbing part a force for inclining the second shock absorbing part outward in the width direction of the vehicle. In the first shock absorbing part, the rigidity of an outer side in the width direction of the vehicle of the side surface is set higher than that of an inner side in the width direction of the vehicle of the side surface o
Asteer Co., Ltd.
Koda & Androlia
Pape Joseph D.
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