JP2004051084A - Impact absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impact absorber capable of attaining the absorption of impact energy by plastic deformation by assuring the immersion of a small pipe body into a large pipe body even if an impact is applied from the axial slanting direction of a larger angle. <P>SOLUTION: The small pipe body 101 and the large pipe body 106 are connected through a step-off portion 110 by partially contracting or expanding the diameter of a straight pipe capable of having plasticity work. The step-off portion 110 is a bumper support type impact absorber 105 formed by jointing a folded edge 107 of the small pipe body and a folded edge 108 of the large pipe body constituted of a circular-arc cross section of which the circular-arc angle is in excess of 90 degrees. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is a shock absorber that absorbs impact energy as deformation energy of plastic deformation, for example, a side member constituting a vehicle body member side portion of a vehicle such as an automobile, or absorbs impact energy applied to a bumper of an automobile or the like. The present invention relates to a shock absorber that can be used as a bumper-supported shock absorber to prevent or suppress transmission of the shock energy to a vehicle body member.
[0002]
[Prior art]
2. Description of the Related Art In vehicles such as automobiles, impact absorbers that absorb impact energy as deformation energy of plastic deformation are used in various places in order to protect an occupant from an impact at the time of a collision. For example, a shock absorber (hereinafter referred to as a bumper support shock absorber) is used as a bumper support type shock absorber composed of a tube body that supports a bumper reinforcement of a vehicle with respect to a vehicle body member.
[0003]
A bumper-supported shock absorber used as a shock absorber is, as seen in Patent Literature 1 and Patent Literature 2, received in an axial direction (corresponding to a direction in which small pipes and large pipes are arranged, which is generally the front-rear direction of a vehicle). The small tubular body is pushed into the large tubular body by the impact energy, thereby causing plastic deformation and absorbing the impact energy as deformation energy of the plastic deformation. The bumper-supporting type shock absorber using the shock absorber has a simple structure and excellent shock energy absorption performance, and has an advantage that the design can be flexibly changed according to a difference in vehicle weight.
[0004]
In addition, as the vehicle body member that holds the occupant compartment, the above-described shock absorber (hereinafter, a side member type shock absorber) is used as a side member formed of a tube constituting a vehicle body member side portion of the vehicle. Prior arts using a shock absorber for a side member include Patent Documents 3 to 7.
[0005]
In Patent Literature 3, the ends of two cylindrical members are coaxially attached to each other, and impact is absorbed by plastic deformation (see FIG. 1 of Patent Literature 3) in which both ends of the cylindrical members are rolled inward from the ends. In Patent Literature 4, impact strength is changed in a length direction by a plurality of holes arranged in two upper and lower stages, and a range of plastic deformation is adjusted according to the degree of impact. In Patent Document 5, the bracket is made of a material having relatively low rigidity, and a bracket is intermittently installed inside. In Patent Document 6, a mirror-symmetric multi-stage cylindrical body is joined. In Patent Literature 7, a shock absorbing member having an elongated hole or a gap is interposed as a part of the structure of the side member.
[0006]
[Patent Document 1]
Japanese Patent Publication No. 47-045986 (pages 2 to 6, FIG. 1 to FIG. 4)
[Patent Document 2]
JP 2001-204841 A (pages 2 to 5, FIG. 2)
[Patent Document 3]
JP 2001-241478 A (pages 2 to 5, FIG. 2)
[Patent Document 4]
Japanese Patent No. 2984434 (2 to 3 pages, FIG. 2)
[Patent Document 5]
JP-B-51-02850 (pages 1 to 4; FIGS. 4 to 8)
[Patent Document 6]
U.S. Pat. No. 3,998,485 (3-4 pages, FIG. 2)
[Patent Document 7]
US Pat. No. 6,312,028 (pages 6 to 7, FIGS. 2 to 1)
[0007]
[Problems to be solved by the invention]
Each impact absorber found in each of the above prior arts has a function of causing a plastic deformation by an impact and absorbing impact energy as deformation energy. This operation is basically the same for the bumper-supported shock absorber and the side member-type shock absorber. For this reason, it is desirable that the shock absorber be plastically deformed stably. In particular, it is necessary that the shock absorber does not bend even when an eccentric load is applied and that the plastic deformation is correctly generated.
[0008]
The bumper-supported shock absorber of Patent Document 1 can exhibit necessary and sufficient absorption performance when an impact is applied from the axial direction in which the small pipes and the large pipes are arranged. However, since the step at the boundary between the small pipe and the large pipe is easily plastically deformed, for example, when an impact is applied to the small pipe obliquely in the axial direction, the small pipe is tilted due to the axial orthogonal component fh of the impact. However, there is a problem in that the plastic deformation due to the immersion of the small tube into the large tube does not occur, and the impact energy cannot be absorbed.
[0009]
The bumper-supported shock absorber of Patent Literature 2 prevents or suppresses the tilting of the small tube by the middle tube using a three-stage bumper-supported shock absorber composed of a small tube, a medium tube, and a large tube. However, the action of preventing or suppressing the tilting of the small tubular body by the middle tubular body is limited (up to approximately 30 degrees in the axial direction), and the tilting of the small tubular body is still prevented against the impact from a larger angle in the axial direction. Cannot be achieved sufficiently.
[0010]
Further, in the side member type shock absorber of Patent Document 3, the edge of the small-diameter tubular member is brought into contact with the step plane provided at the edge of the large-diameter tubular member, and therefore, the axial direction in which the tubular members are arranged. , It is possible to cause plastic deformation at the edges of both tubular members via the step plane. However, in the case of an unbalanced load, there is a problem that the small-diameter cylindrical member is inclined and bent on the step plane.
[0011]
In addition, the side member type shock absorbers disclosed in Patent Document 4, Patent Document 5, and Patent Document 7 have difficulty in obtaining a stable shock absorbing performance (in particular, see FIG. 4 load characteristics of Patent Document 4). The side member type shock absorber shown in JP-A-2003-157404 may be bent by an unbalanced load as in Patent Document 3.
[0012]
Therefore, even if an impact is applied to the bumper-supported shock absorber or the side member-type shock absorber obliquely at a larger angle in the axial direction, the small tube is still immersed in the large tube, and the impact due to plastic deformation is ensured. We considered that energy absorption could be achieved.
[0013]
[Means for Solving the Problems]
As a result of the study, the small pipe or large pipe connected through the step is formed by partially reducing or expanding the diameter of the straight pipe that can be plastically processed, and the folded edge and large size of the small pipe connected through the step are formed. We have developed a shock absorber in which the folded edges of the tubes are both arc-shaped cross sections with an arc angle of more than 90 degrees, and the steps have an S-shaped cross section connecting the folded edges of the small and large tubes.
[0014]
The term “exceeding 90 degrees” referred to in the present invention refers to the angle range of the arc portion of the folded edge of the small tube which is bent from the side of the small tube to the step, or the folding of the small tube which is bent from the side of the large tube to the step. This means that the angle range of the arc portion of the edge is not 90 degrees (right angle).
[0015]
Here, when the straight pipe that supports the bumper reinforcement of the vehicle with respect to the vehicle body member is partially reduced or enlarged to form a small pipe and a large pipe that are connected via a step, the bumper reinforcement is supported. It is a shock absorber that can also serve as a structural element (hereinafter, bumper-supported shock absorber). In addition, when a small pipe and a large pipe connected to each other through a step by partially reducing or expanding the diameter of a straight pipe forming a side part of a vehicle body member of a vehicle, an impact which becomes a structural element forming the body member itself is obtained. It becomes an absorber (hereinafter, a side member type shock absorber).
[0016]
The shock absorber of the present invention can be applied to a multi-stage tube having one or more steps, but a two-stage tube consisting of a small tube and a large tube, or a three-stage tube consisting of a small tube, a medium tube, and a large tube The body is preferred. Here, in the three-stage tube, the relationship between the small tube and the middle tube, the relationship between the middle tube and the large tube respectively corresponds to the relationship between the small tube and the large tube of the two-stage tube, and as a whole, the shock absorber is used. It is a linked configuration.
[0017]
Since the shock absorber of the present invention forms a small pipe or a large pipe by partially reducing or expanding the diameter of a plastically processable straight pipe, the wall thickness of the large pipe is smaller than the small pipe, In addition, large pipes are more prone to plastic deformation. In addition, the step interposed between the small pipe and the large pipe has an S-shaped cross section in which the small pipe is slightly immersed in the large pipe and the step is rolled inward. Easy to immerse your body.
[0018]
From this, the shock absorber of the present invention causes plastic deformation in which the small pipe is immersed in the large pipe as it is and rolls inward from the step to the side of the large pipe, and absorbs impact energy as deformation energy of the plastic deformation. I do.
[0019]
The arc angle of each arc-shaped cross section of the folded edge of the small tubular body and the folded edge of the large tubular body is considered to be in a range of more than 90 degrees and less than 360 degrees. The specific arc angles are (1) the difference between the outer diameter of the small tube and the inner diameter of the large tube, (2) the arc-shaped cross section of the folded edge of the small tube and the arc-shaped cross section of the folded edge of the large tube. (The definition of the radius will be described later). More specifically, each arc angle of the arc-shaped cross section of both side edges is preferably about 180 degrees.
[0020]
To reliably generate plastic deformation in which the small pipe immerses into the large pipe and rolls inward from the step to the side of the large pipe, the radius of the arc-shaped cross section of the folded edge of the small pipe is determined by the large pipe Of the S-shaped cross section relatively smaller than the radius of the arc-shaped cross section of the folded edge. Here, since the folded edge of the small tube and the folded edge of the large tube that are continuous with the small tube side surface and the large tube side having different thicknesses are each curved while changing the thickness, the radius of each of the arc-shaped cross sections is Is the radius of the center line of the plate thickness.
[0021]
The step of the above cross-sectional structure suppresses the winding of the side surface of the small tubular body through the folded edge of the small tubular body that is relatively steeply folded, and conversely, the folded edge of the large tubular body that is relatively loosely folded. Induces the side of the large tube to be entangled. Thereby, the small tube is immersed in the large tube as it is, and plastic deformation can be realized in which the small tube is rolled inward from the folded edge of the large tube to the side surface of the large tube.
[0022]
As described above, the present invention realizes plastic deformation in which a small tube is always immersed toward a large tube by devising a structure of a step. However, when an impact (biased load) is applied to the small tube from an oblique direction, the small tube inclines with respect to the large tube, and the side surface of the small tube hits the folded edge of the large tube to prevent the immersion of the small tube. There is a possibility that it will be done.
[0023]
Therefore, the step is preferably an S-shaped cross section in which the folded edge of the small tubular body and the folded edge of the large tubular body are connected by an annular side surface. The radius of each arc-shaped cross section of the folded edge of the small tube and the folded edge of the large tube may be the same or different. That is, as described above, even when the radius of the arc-shaped cross section of the folded edge of the small tubular body is relatively smaller than the radius of the arc-shaped cross section of the folded edge of the large tubular body, the annular side surface causes the roll-up to be hindered. It does not become.
[0024]
The annular side surface is parallel to the small tube side surface and the large tube side surface when a step of an S-shaped cross section connecting the folded edge of the small tube body and the folded edge of the large tube body having the same arc angle of 180 degrees is formed. However, by changing the radius of each of the arc-shaped cross-sections of the folded edge of the small tube and the folded edge of the large tube, the frustoconical surface whose diameter gradually decreases or expands from the small tube toward the large tube. Is preferable. More preferably, the radius of the arc-shaped cross-section of the folded edge of the small tube is relatively smaller than the radius of the arc-shaped cross-section of the folded edge of the large tube to form a step having an S-shaped cross-section, and the step is opened toward the small tube. The shape is an inverted frustum-shaped annular side surface.
[0025]
The annular side surface connecting the folded edge of the small tubular body and the folded edge of the large tubular body should be separated from the folded edge of the large tubular body by turning the folded edge of the small tubular body, which becomes the tilt axis, when the small tubular body is inclined by an oblique impact. Therefore, the small tube side is brought into contact with the folded edge or the annular side surface of the large tube at an early stage to prevent the small tube from tilting greatly. At the stage when the small tube starts to sink into the large tube, the inclination is corrected while sliding the small tube side against the folded edge or annular side surface of the large tube, and the small tube is securely inserted into the large tube. Guarantee.
[0026]
In order to more positively prevent the tilting of the small tubular body, it is preferable to attach an anti-tilt body for suppressing or preventing the tilting of the small annular body itself when immersing in the large tubular body to the inner surface of the small tubular body. This tilting prevention body is composed of a small-diameter ring having an outer diameter equal to the inner diameter of the small tube and a large-diameter ring having an outer diameter equal to the inner diameter of the large tube, and the small-diameter ring is fixed to the inner surface of the small tube, By projecting from the small tubular body to the large tubular body beyond the step, the large-diameter annular portion is brought into contact with the inner surface of the large tubular body at a position where the small-diameter annular portion exceeds the step, so that the small-diameter annular portion is added to the small tubular body obliquely in the axial direction. An anti-tilt body integral with the small tube counters the received impact on the basis of the inner surface of the large tube to prevent or suppress the small tube from tilting.
[0027]
Here, `` abut on the inner surface of the large tube '' means that when the small tube is immersed in the large tube, the large-diameter ring portion is continuously or intermittently on the inner surface of the large tube. Including point contact, line contact or surface contact. In addition, the large-diameter ring portion does not need to contact the whole, and if there is a point contact, it is sufficient if there is a plurality of points of contact in the direction in which the small ring is desired to be tilted. Intermittently.
[0028]
In order for the anti-tilt body to exhibit the function of suppressing or preventing the tilting of the small ring itself immersed in the large pipe, the small pipe needs to be smoothly immersed in the large pipe. From this, it is possible to form a step having an S-shaped cross section in which the radius of the arc-shaped cross section of the folded edge of the small pipe is relatively smaller than the radius of the arc-shaped cross section of the folded edge of the large pipe together with the application of the anti-tilt body. desirable.
[0029]
The small-diameter ring portion and the large-diameter ring portion that constitute the above-described tilting prevention member may be formed by separate members and connected together, or a plastically deformable ring body, like the stepped pipe that constitutes the shock absorber. The diameter may be partially reduced or expanded to be integrally formed through a step. In this case, the small-diameter ring corresponds to the small pipe, and the large-diameter ring corresponds to the large pipe. However, since the tilting prevention body does not require the shock absorbing action by plastic deformation, a step connecting the small-diameter ring and the large-diameter ring is required. Does not require the structural limitation described above.
[0030]
An anti-tilt body in which a plastically deformable ring is partially reduced or expanded in diameter and integrally formed through a step makes a small-diameter ring projecting from the small tube into the large tube abut on the inner surface of the large tube. It is advisable to form a large-diameter ring portion by expanding the diameter to the maximum. That is, the small-diameter annular portion is formed in a relatively long tubular shape, and the diameter of the small-diameter annular portion is increased until it comes into contact with the inner surface of the large tubular body.
[0031]
In addition, the anti-tilt body expands a small-diameter ring portion protruding from the small tube to the large tube until it comes into contact with the inner surface of the large tube, and forms a large-diameter ring as curling turned toward the small tube. Alternatively, the small-diameter annular portion protruding from the small tubular body to the large tubular body may be enlarged until it comes into contact with the inner surface of the large tubular body, and the large-diameter annular portion may be formed as a curling which is turned inward in a radius of the large tubular body. Thus, by forming the large-diameter annular portion by curling, it is possible to give the large-diameter annular portion a structural strength against an impact applied obliquely in the axial direction.
[0032]
Furthermore, it is preferable that the large-diameter annular portion of the anti-tilt body be provided with a cylindrical ring that is in contact with the inner surface of the large tube. A tubular ring that contacts the inner surface of the large tube with a large area reduces the pressure (impact force / contact surface area) due to the impact applied obliquely in the axial direction, and prevents or suppresses the small tube from tilting. Strengthen the work of. Since this cylindrical ring is in contact with the inner surface of the large tube, it has a basically similar shape to the large tube. The curling may be formed at the edge of the cylindrical ring.
[0033]
The anti-tilt body of the present invention only needs to be able to counter the tilt of the small tubular body on the basis of the large tubular body. From this, the small tubular body is formed integrally with the inner surface of an anti-tilt body for suppressing or preventing the tilt of the small tubular body itself when immersed in the large tubular body, and the tilt-preventing body forms the folded edge of the small tubular body with the large tubular body. It can also be formed by expanding toward the inner surface of.
[0034]
The above-mentioned tilting prevention body is configured such that the radius of the arc-shaped cross section of the folded edge of the small tube is relatively smaller than the radius of the arc-shaped cross section of the folded edge of the large tube. , The folded edge of the small tube having an S-shaped cross section in which the folded edge of the small tube and the folded edge of the large tube are connected by an annular side surface, It is formed by expanding toward the inner surface of the tube. Each of the tilt-preventing members can make the folded edge of the small tube slidably contact the inner surface of the large tube as the tilt-preventing member, while ensuring that the small tube is immersed in the large tube.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a bumper-supported shock absorber will be described with reference to the drawings. FIG. 1 is a perspective view showing a use mode of a bumper supporting type shock absorber 105 and a side member type shock absorber 112 of the present invention. FIG. 2 is a diagram showing a large-diameter ring portion 103 formed by a curling 102 folded toward a small tube 101. FIG. 3 is a cross-sectional view of a bumper-supported shock absorber 105 having a two-stage tube structure to which the tilt-preventing body 104 is attached. FIG. 3 shows a stage in which an axial shock F starts to be applied to the bumper-supported shock absorber 105. FIG. 4 is a cross-sectional view corresponding to FIG. 2, and FIG. 4 is a cross-sectional view corresponding to FIG. 2 showing a stage in which an impact F starts to be applied to the bumper-supported shock absorber 105 obliquely in the axial direction. FIG. 3 is a cross-sectional view corresponding to FIG.
[0036]
As shown in FIG. 2, the bumper-supported shock absorber 105 of the present embodiment includes a small pipe 101 and a large pipe 106 which are formed by partially reducing or expanding a plastically processable straight pipe through a step. Formed of a two-stage tube. In this example, the small pipe 101 and the large pipe 106 are contracted in the axial direction (refer to a dashed line in FIG. 2; the same applies hereinafter), the folded edge 107 of the small pipe having a small radius of curvature and the large pipe having a large radius of curvature. A step 110 having an S-shaped cross-section is formed by connecting the folded edge 108 of the sheet with an annular side surface 109. As shown in FIG. 1, the bumper supporting type shock absorber 105 has a large pipe 106 connected to each of the front ends of side member type shock absorbers 112 constituting a vehicle body member 111, and bumpers attached to the small pipes 101, 101. It is used in a mode in which the reinforcing member 113 is erected.
[0037]
The tilt preventing body 104 of the present example includes a small-diameter ring portion 114 having an outer diameter equal to the inner diameter of the small tube 101 and a large-diameter ring portion 103 having an outer diameter equal to the inner diameter of the large tube 106. The large-diameter annular portion 103 is a curling 102 which is formed by expanding a small-diameter annular portion 114 protruding from the small tubular body 101 to the large tubular body 106 until the small-diameter annular portion 114 comes into contact with the inner surface of the large tubular body 106 and turned back toward the small tubular body 101. The edge of the curling 102 is brought into contact with the inner surface of the large tube 106 at a position beyond the step 110. The tilt preventing body 104 is fixed to the inner surface of the small tube body 101 by spot welding (spot welding marks 115 are shown in FIG. 2).
[0038]
When an impact F (open arrow in FIG. 3) is applied to the small tubular body 101 from the axial direction, the small tubular body 101 is immersed in the large tubular body 106 as shown in FIG. While extending the annular side surface 109, the large pipe 106 is rolled inward by the small pipe 101 through the step 110 (plastic deformation: black arrow in FIG. 3), and the impact energy of the impact F is deformed to the large pipe 106. Absorb as energy. Here, the annular side surface 109 and the large tubular body 106 are each accompanied by plastic deformation (ductility), but most of the plastic deformation occurs in a mode in which the annular side surface 109 extends in accordance with the amount of the large tubular body 106 being rolled up. .
[0039]
In the case of the present example, the folded edge 107 of the small tube sandwiching the step 110 has an arc-shaped cross section with a relatively small radius, and the folded edge 108 of the large tube has an arc-shaped cross section with a relatively large radius. In addition, the folded edge 108 of the large tube is easily plastically deformed, and the large tube 106 is unilaterally rolled without the small tube 101 being rolled. As described above, the plastic deformation for absorbing the impact energy of the impact F is achieved only by the winding of the large pipe 106 having a large diameter. The total amount of impact energy that can be produced is large.
[0040]
Further, in this example, since the step 110 is formed by connecting the folded edge 107 of the small tubular body and the folded edge 108 of the large tubular body with the annular side surface 109, the process of the small tubular body 101 immersing in the large tubular body 106 is performed. Is extended between the small tube 101 and the large tube 106. The annular side surface 109 interposed between the small tube 101 and the large tube 106 has a function of preventing or suppressing the tilting of the small tube 101, and as shown in FIG. At the stage of immersion, there is no longer a possibility that the small tubular body 101 is tilted.
[0041]
The problem is that the impact F is applied obliquely from the beginning. As shown in FIG. 4, the impact F applied obliquely in the axial direction causes an axial component fv (solid arrow pointing downward in FIG. 4) pushing the small tube 101 against the large tube 106 and tilting the small tube 101. It can be decomposed into an axis orthogonal component fh (solid right arrow in FIG. 4) to be made.
[0042]
The tilt preventing body 104 opposes the folded edge 107 of the small tube approaching the inner surface of the large tube 106 on the upstream side of the axis orthogonal component fh with respect to the small tube 101 that is inclined to receive the axis orthogonal component fh. 4 (see the solid arrow and the dashed arrow on the right side in FIG. 4), and opposes that the folded edge 107 of the small tube is separated from the inner surface of the large tube 106 on the downstream side of the axis orthogonal component fh (the solid line on the left in FIG. 4). Arrows and dashed arrows).
[0043]
The opposition is realized by the large-diameter annular portion 103 abutting on the inner surface of the large tubular body 106 and the tilt preventing body 104 being restricted in the tilting direction of the small tubular body 101. That is, in order for the small tubular body 101 to incline, a load enough to break the restriction of freedom = an impact sufficient to deform the entire antitilt body 104 must be applied. The anti-tilt body 104 has the small-diameter ring 114 in contact with the small tube 101 and is fixed thereto, and the curling 102 constituting the large-diameter ring 103 is also in contact with the large tube 106. In addition, the deformation of the tilt preventing body 104 requires the entire deformation.
[0044]
Furthermore, since the tilt prevention body 104 of this example is substantially cylindrical, the load required for deformation of the tilt prevention body 104 can be equalized regardless of the direction in which the axis orthogonal component fh is applied to the small tubular body 101. As described above, the small-diameter annular portion 114 is fixed to the inner surface of the small tubular body 101 and the large-diameter annular portion 103 is provided with the tilt preventing body 104 that abuts against the inner surface of the large tubular body 106, whereby the small tubular body 101 is tilted (particularly, tilted). The tilting at the initial stage when the impact F starts to be applied) can be prevented.
[0045]
As described above, if the small tubular body 101 is partially immersed in the large tubular body 106, the annular side surface 109 can prevent the small tubular body 101 from tilting. Even if a shock F obliquely applied in the axial direction is applied, the small tube 101 can be reliably immersed in the large tube 106 without tilting, and the shock energy of the shock F can be absorbed.
[0046]
As shown in FIG. 5, the small tube body 101 whose inclination has been prevented has a curling 102 which constitutes a large-diameter annular portion 103 of an inclination prevention body 104 and a front end of a side member type shock absorber 112 (see FIG. Until it abuts against the edge of the body 106). The amount of impact energy of the impact F that can be absorbed as a bumper-supported impact absorber is determined by the amount of immersion of the small tubular body. By doing so, it is possible to further immerse the small tubular body. In this case, since there is no foundation on which the large-diameter ring portion abuts, it is preferable to provide a guide that can continuously contact the large-diameter ring portion with the immersion hole.
[0047]
FIG. 6 shows another example of a tilt prevention body 118 in which a large-diameter ring portion 103 is formed by a curling 116 turned inward in a radius of the large pipe 106 and a cylindrical ring 117 in contact with the inner surface of the large pipe 106. FIG. 7 is a cross-sectional view corresponding to FIG. 2 of the bumper-supported shock absorber 119 having a two-stage tubular structure. FIG. 7 shows a stage in which the bumper-supported shock absorber 119 has finished absorbing the impact energy of the impact F in the axial direction. FIG. 7 is a sectional view corresponding to FIG.
[0048]
In order to counter the tilting of the small tubular body, the tilt preventing body may have a structure having a large-diameter ring portion capable of resisting the component fh orthogonal to the axis of the impact F based on the inner surface of the large tubular body. As shown in FIG. 6, the large-diameter annular portion 103 of the present example expands a small-diameter annular portion 114 protruding from the small tubular body 101 to the large tubular body 106 until the small-diameter annular portion 114 comes into contact with the inner surface of the large tubular body 106. This is a structure in which a cylindrical ring 117 that is in contact with the inner surface of the body 106 is formed, and then the curling 116 is formed by turning the radius of the large tube body 106 inward.
[0049]
The function of the large-diameter annular portion 103 of the present example for preventing the small tubular body 101 from tilting is not different from the above-described example (see FIG. 2 and subsequent figures). The tubular ring 117 that widely contacts the inner surface of the large tube 106 has a function of enhancing the resistance to tilting of the small tube 101. In this example, since the curling 116 inward in the radial direction of the large tube body 106 is further formed following the cylindrical ring 117, the structural strength of the large diameter ring portion 103 is high, and the tilting of the small tube body is prevented better. it can.
[0050]
Here, the large-diameter annular portion 103 having a width in the axial direction including the cylindrical ring 117 restricts the displacement of the folded edge 107 of the small tube 101 of the small tube 101 immersed in the large tube 106, as shown in FIG. As a result, the amount of immersion of the small tubular body 101 is reduced. In this case, by eliminating the curling following the tubular ring, the large-diameter ring portion plane leading to the tubular ring leaves room for plastic deformation, for example, by crushing the large-diameter ring portion 103 at the folded edge of the small tube, You can also gain the amount of immersion of the tubule.
[0051]
FIG. 8 shows another example in which the folded edge of the small tubular body of the step 120 formed by connecting the folded edge 107 of the small tubular body and the folded edge 108 of the large tubular body is expanded toward the inner surface of the large tubular body 106. FIG. 9 is a sectional view corresponding to FIG. 2 of a bumper-supported shock absorber 122 having a two-stage tubular structure provided with an anti-tilt body 121. FIG. FIG. 9 is a cross-sectional view corresponding to FIG. 8, illustrating a stage in which absorption has been completed.
[0052]
Although the bumper-supporting type shock absorber and the tilting preventive body which are separate from each other are preferred because of their high degree of freedom in design and manufacture, they require an assembling step of fixing the small-diameter annular portion integral with the large-diameter annular portion to the small tubular body. On the other hand, the tilting prevention body 121 shown in FIG. 8 has an advantage that it does not require an assembling step of fixing the small-diameter annular portion to the small tubular body because only the large-diameter annular portion 103 is formed integrally with the small tubular body 101. .
[0053]
The anti-tilt body 121 of the present example forms a step 120 connecting the folded edge 107 of the small tubular body with a small radius of curvature cross section and the folded edge 108 of the large tubular body with a large radius of curvature cross section, and forms the folded edge 107 of the small tubular body. It is expanded toward the inner surface of the large tube 106 and abuts against the inner surface of the large tube 106 to form. Although it is not an upwardly open shape as seen in each of the above-described examples, the annular side surface connecting the folded edge 107 of the small tube and the folded edge 108 of the large tube corresponds to the annular side surface 109, and is integrated with the small tube 101. The tilting prevention of the small tube body 101 can be aimed at together with the tilting prevention body 121 formed.
[0054]
The small tubular body 101 receives the impact F from the axial direction and pushes the folded edge 107 of the small tubular body outward in the radial direction of the large tubular body 106 while immersing in the large tubular body 106. The folded edge 107 always comes into sliding contact with the inner surface of the large tube 106 while the small tube 101 is immersed in the large tube 106. Since the tilting prevention body 121 of this example is expanded at a gentle curvature from the small tube 101 to the folded edge 107 of the small tube, the small tube 101 has a lower end at the front end of the side member type shock absorber 112 (see FIG. 1). , The edge of the large tube 106), as shown in FIG. 9, the small tube is plastically deformed from the folded edge 107 to the small tube 101 and slightly spreads to stop immersion.
[0055]
Next, an embodiment of a side member type shock absorber will be described with reference to the drawings. 10 is an axial sectional view of the side member type shock absorber 112, FIG. 11 is an axial sectional view of another example of the side member shock absorber 112, FIG. 12 is an enlarged sectional view of a portion A in FIG. FIG. 13 is a sectional view corresponding to FIG. 12 illustrating a process of immersing the small tubular body 201 in the large tubular body 202.
[0056]
In this embodiment, as shown in FIGS. 1 and 10, a cross member 124 is provided between the expanded mounting tips 123 of the small tubular body 201 constituting the side member type shock absorber 112 so that the vehicle body member 111 is attached. The bumper reinforcing member 113 is supported by a bumper supporting type shock absorber 105 protruding from the cross member 124 coaxially with each of the small pipes 201. The reason why the mounting tip 123 is expanded is to increase the joining strength between the cross member 124 and the side member type shock absorber 112. In addition, as shown in FIG. The tip of the body 201 may be directly inserted and joined.
[0057]
Since the present invention reliably causes plastic deformation from the folded edge 204 of the large tube of the step 203 to the side surface 205 of the large tube, as shown in FIG. A folded edge 206 of a small tubular body and a folded edge 204 of a large tubular body having an arc-shaped cross section with an arc angle of 180 degrees continuously formed from both tubular body side surfaces 207 and 205 of the tubular body 202 are formed.
[0058]
In particular, in this example, the radius of the arc-shaped cross section of the folded edge 204 of the large tube is set to be approximately 1.7 times larger than the radius of the arc-shaped cross section of the folded edge 206 of the small tube. With this radius ratio, as is clear from FIG. 12, the folded edge 206 of the small tube is relatively steeply folded, and the folded edge 204 of the large tube is relatively gently continuous with the side surface 205 of the large tube. Structure.
[0059]
By connecting the small tube 201 and the large tube 202 via such a step 203, the outer diameter of the small tube 201 becomes smaller than the inner diameter of the large tube 202, and as shown in FIG. When the impact F is applied in the axial direction of the mold shock absorber 112, the small tube 201 is moved to the large tube 202 after or almost simultaneously with the shock absorption (in this example, the shock absorption by plastic deformation) in the bumper-supported shock absorber 105. Immerse yourself.
[0060]
The immersion of the small tube into the large tube is based mainly on plastic deformation from the folded edge of the large tube to the side surface of the large tube (see a thick arrow in FIG. 13). This is because the diameter of the straight pipe is expanded to form the large pipe 202 (or the diameter of the straight pipe is reduced to form the small pipe 201). This is because the large tube 202 can be relatively easily plastically deformed more than the small tube 201. Since this plastic deformation occurs continuously so that the large tubular body side surface 205 is rolled inward, there is an advantage that stable absorption of high impact energy can be realized.
[0061]
In order to prevent the small tube 201 from tilting when the impact F is applied from an oblique direction, a step 203 connecting the folded edge 206 of the small tube and the folded edge 204 of the large tube with an annular side surface 208 may be formed. FIG. 14 is equivalent to FIG. 12 of the side member type shock absorber 112 in which the folded edge 206 of the small tube and the folded edge 204 of the large tube are connected by the cylindrical annular side surface 208 parallel to the small tube side 207 and the large tube side 205. 15 is a sectional view corresponding to FIG. 14 showing a state in which the small tubular body 201 is slightly tilted in response to an oblique impact F, and FIG. FIG. 15 is a sectional view corresponding to FIG. 14, showing a state in which a body 201 is immersed in a large tubular body 202.
[0062]
As shown in FIG. 14, the side member type shock absorber 112 of this example is separated from the folded edge 204 of the large pipe having a relatively large radius in the direction of immersion of the small pipe 201 so as to have the folded edge 206 of the small pipe. To form a step 203 connecting the folded edge 206 of the small tubular body and the folded edge 204 of the large tubular body with a cylindrical annular side surface 208.
[0063]
Since the small tubular body 201 does not adhere the small tubular body side surface 207 to the annular side surface 208, when the impact F is applied from an oblique direction deviated from the axial direction of the side member type shock absorber 112, as shown in FIG. Meanwhile, the small tubular body side surface 207 is tilted with the folded edge 206 of the small tubular body as an axis of inclination until the small tubular body side surface 207 comes into contact with the annular side surface 208 or the folded edge 204 of the large tubular body. When the small tube 201 is in contact with the folded edge 204, the inclination of the small tube 201 is restricted.
[0064]
Further, when the impact F is further applied, the component fh in the axis orthogonal direction of the side member type shock absorber 112 of the impact F is received by the annular side surface 208, and the inclination of the small tubular body 201 cannot be advanced. As can be seen, only the axial component fv of the impact F of the side member type shock absorber 112 contributes to the movement of the small tube 201 into the large tube 202.
[0065]
The tilting of the small tubular body has the folding edge of the small tubular body as a tilt axis, and is allowed only in a range of a tangent from the folded edge of the small tubular body to the circular side surface or the arc-shaped cross section of the folded edge of the large tubular body. Therefore, at the stage where the small tube 201 is immersed in the large tube 202, the small tube 201 temporarily corrects the tilt while sliding the small tube side surface 207 on the annular side surface 208 or the arc-shaped cross section of the folded edge 204 of the large tube. The impact F can contribute only to the plastic deformation that causes the large tubular body side surface 205 to be rolled inward from the step 203.
[0066]
The annular side surface 208 may not be parallel to the small tube side 207 or the large tube side 205. FIG. 17 is a cross-sectional view corresponding to FIG. 12 of the side member type shock absorber 112 in which the truncated conical annular side surface 209 which reduces in diameter from the small tube body 201 toward the large tube body 202 is shown. FIG. 18 is a cross-sectional view corresponding to FIG. 17, illustrating a state in which the small pipe 201 is received and sunk into the large pipe 202.
[0067]
The annular side surface prevents the small tubular body from tilting, and directly contacts the tilting small tubular body side surface, and indirectly forms the arc-shaped cross section of the folded edge of the small tubular body as the tilting axis of the large tubular body. By restricting the tilt angle away from the arc-shaped cross section of the folded edge, the tilt of the small tubular body is prevented. From this, the shape of the annular side surface is free as long as the tilting prevention function can be exhibited, and as shown in FIGS. 17 and 18, even the frustoconical annular side surface 209 allows the small tube 201 to move to the large tube 202 without being hindered. It can be immersive.
[0068]
【The invention's effect】
According to the shock absorber of the present invention, even when an impact is applied from an oblique direction at a larger angle than in the past, the small pipe body can still be immersed in the large pipe body by specifying the step shape and attaching the tilt prevention body. As a result, it is possible to sufficiently exhibit the shock absorbing performance of absorbing the impact energy as the deformation energy of the plastic deformation.
[0069]
Conventionally, the small tubular body tilts up to about 30 degrees in the axial diagonal direction. However, in the bumper-supported shock absorber of the present invention, the axial orthogonal component fh is up to 45 degrees in the axial diagonal direction exceeding the axial component fv. Within the range, the immersion of the small tube into the large tube can be ensured. The tilting prevention body has an effect of preventing or suppressing the tilting of the small tubular body with a simple structure.
[0070]
The present invention provides a bumper-supporting-type shock absorber composed of a tube for supporting a vehicle bumper reinforcing material to a vehicle body member, and a side member-type shock absorber composed of a tube constituting a vehicle body member side portion of a vehicle. I do. In the case of the side member type shock absorber, it is possible to avoid the risk of being bent at the step and coming into contact with the vehicle body or the fuel tank, and an effect of improving safety is obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating a usage mode of a bumper-supported shock absorber and a side member type shock absorber.
FIG. 2 is a cross-sectional view of a bumper-supported shock absorber to which an anti-tilt body formed with a large-diameter annular portion of curling toward a small tubular body is attached.
FIG. 3 is a sectional view corresponding to FIG. 2, showing a stage in which an impact F in the axial direction starts to be applied to the bumper-supported shock absorber.
FIG. 4 is a sectional view corresponding to FIG. 2, showing a stage in which an impact F starts to be applied to the bumper-supported shock absorber obliquely in the axial direction.
FIG. 5 is a sectional view corresponding to FIG. 2, showing a stage in which the bumper-supported shock absorber has completely absorbed an axial shock F;
FIG. 6 is a sectional view, corresponding to FIG. 2, of a bumper-supported shock absorber to which an anti-tilt body having a large-diameter ring formed by a curling and a tubular ring is attached.
FIG. 7 is a cross-sectional view corresponding to FIG. 6, illustrating a stage in which the bumper-supported shock absorber has completely absorbed the shock F in the axial direction.
FIG. 8 is a sectional view corresponding to FIG. 2 of a bumper-supported shock absorber provided with an anti-tilt body formed by expanding a folded edge of a small tubular body.
FIG. 9 is a sectional view corresponding to FIG. 8, illustrating a stage in which the bumper-supported shock absorber has completely absorbed the shock F in the axial direction.
FIG. 10 is an axial sectional view of a side member type shock absorber.
FIG. 11 is an axial sectional view of another example of a side member type shock absorber.
FIG. 12 is an enlarged sectional view of a portion A in FIG. 10;
FIG. 13 is a sectional view corresponding to FIG. 12, showing a process of immersing the small tubular body into the large tubular body.
FIG. 14 is a sectional view corresponding to FIG. 12 of a side member type shock absorber in which a folded edge of a small tube and a folded edge of a large tube are connected by a cylindrical annular side surface.
FIG. 15 is a sectional view corresponding to FIG. 14, showing a state in which the small tubular body is slightly tilted by receiving an impact F from an oblique direction.
FIG. 16 is a sectional view corresponding to FIG. 14 showing a state in which the application of the impact F continues and the small tube is immersed in the large tube while correcting the tilt.
17 is a sectional view corresponding to FIG. 12 of a side member type shock absorber having a frustoconical annular side surface.
FIG. 18 is a sectional view corresponding to FIG. 17, showing a state in which a small tubular body is immersed in a large tubular body in response to application of an impact F;
[Explanation of symbols]
101 tubule
102 Curling
103 Large diameter ring
104 Anti-tilt body
105 Bumper supported shock absorber
106 Large tube
107 Folded edge of small tubular body
108 Folded edge of large pipe
109 Annular side
110 steps
112 Side member type shock absorber
114 Small diameter ring
116 Curling
117 Cylindrical ring
201 small tubular body
202 Large tube
203 steps
204 Folded edge of large pipe
205 Large tube side
206 Folded edge of tubule
207 Small tube side
208 Annular side
209 Frustoconical annular side surface
F impact
fv axial component of impact
fh Directional component of impact

Claims (12)

A small pipe or large pipe connected through a step is formed by partially reducing or expanding the diameter of a straight pipe that can be plastically processed, and the folded edge and the large pipe of the small pipe connected through the step are formed. The shock absorber has an edge having an arc-shaped cross section having an arc angle of more than 90 degrees, and a step having an S-shaped cross section connecting the turning edge of the small pipe and the turning edge of the large pipe. 2. The shock absorber according to claim 1, wherein the straight pipe supporting the bumper reinforcement of the vehicle to the vehicle body member is partially reduced in diameter or enlarged to form a small pipe and a large pipe connected via a step. . 2. The shock absorber according to claim 1, wherein a small pipe and a large pipe which are connected to each other through a step by partially reducing or expanding the diameter of a straight pipe constituting a vehicle body member side portion of the vehicle. 2. The shock absorber according to claim 1, wherein the step has an S-shaped cross-section in which the radius of the arc-shaped cross section of the folded edge of the small tube is relatively smaller than the radius of the arc-shaped cross-section of the folded edge of the large tube. 2. The shock absorber according to claim 1, wherein the step has an S-shaped cross section in which the folded edge of the small tube and the folded edge of the large tube are connected by an annular side surface. The small tubular body has an anti-tilt body fixed to the inner surface for suppressing or preventing tilting of the small tubular body itself when immersed in the large tubular body. A large-diameter annular portion having an outer diameter equal to the inner diameter of the large-diameter tube, the small-diameter annular portion is fixed to the inner surface of the small-diameter tube, and projects from the small-diameter tube to the large-diameter tube over the step. 2. The shock absorber according to claim 1, wherein the small-diameter annular portion is in contact with the inner surface of the large pipe at a position beyond the step. 7. The shock absorber according to claim 6, wherein the tilt-preventing body forms a large-diameter annular portion by expanding a small-diameter annular portion projecting from the small tubular body to the large tubular body until the small-diameter annular portion comes into contact with the inner surface of the large tubular body. The tilt preventing body is formed by expanding a small-diameter annular portion protruding from the small tubular body to the large tubular body until it comes into contact with an inner surface of the large tubular body, and forming a large-diameter annular portion as curling folded toward the small tubular body. Item 7. The shock absorber according to Item 6. 7. The shock absorber according to claim 6, wherein the tilt-preventing body is provided with a cylindrical ring in contact with the inner surface of the large tube at the large-diameter ring portion. The small tubular body is formed integrally with an inner surface of an anti-tilt body for suppressing or preventing tilting of the small tubular body itself when immersed in the large tubular body. The shock absorber according to claim 1, wherein the shock absorber is formed so as to expand toward the surface. The anti-tilt body has a folded edge of the small tubular body having an S-shaped step with the radius of the arc-shaped cross section of the folded edge of the small tubular body relatively smaller than the radius of the arc-shaped cross section of the folded edge of the large tubular body, The shock absorber according to claim 10, wherein the shock absorber is formed by expanding toward an inner surface of the large pipe. The tilting prevention body is formed by expanding the folded edge of the small tube having a step of an S-shaped cross section connecting the folded edge of the small tube and the folded edge of the large tube with an annular side surface toward the inner surface of the large tube. The shock absorber according to claim 10, which is formed.

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