JP3327030B2 - Impact energy absorbing device and its mounting structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a collision energy absorbing device and a mounting structure thereof, and more particularly to a collision energy absorbing device suitable for mounting on a front side member or a rear side member of an automobile, and a special seat for the collision energy absorbing device. The present invention relates to a mounting structure suitable for mounting on a surface.

[0002]

2. Description of the Related Art There has been proposed an energy absorbing structure in which a substantially box-shaped bracket having a rigidity smaller than the rigidity of the front side member is disposed between a front end portion of a front side member of an automobile and a bumper (Japanese Patent Laid-Open Publication No. H11-163873). 63-18054
No. 4). The bracket has a form of an energy absorbing device (U.S. Pat. No. 5,224,574) in which a plurality of cylindrical energy absorbers having different diameters are connected via a step portion to form a stepped shape tapering in the axial direction. Energy can be absorbed more effectively.

[0003] The energy absorbing device 10 according to the aforementioned US Patent
As shown in FIG. 8, among the plurality of energy absorbers 11, 12, and 13 in the illustrated embodiment having different diameters, adjacent ones of the energy absorbers 11, 12, and 13 have an annular stepped portion. 14, 13 and 12 of diameter adjacent to each other
Are connected via an annular step portion 15, and are embodied in a stepped shape tapered in the axial direction. The energy absorber 13 having the smallest diameter is closed by the lid 16.

When a load F of a predetermined magnitude or more is applied to the energy absorbing device 10 during use, first, as shown in FIG.
5 and is further deformed so as to be bent substantially at the center to absorb energy. When the load is further increased, the energy absorber 12 having a larger diameter than the energy absorber 13 is bent at the step portion 14 and deforms so as to be bent substantially at the center to absorb energy. Then, in a state where the energy is completely absorbed, the entire shape becomes flat. On the other hand, as shown in FIG. 8D, the load A and the displacement amount of the energy absorbing device 10, that is, the stroke S, have a characteristic A ₁₃ obtained by the deformation of the energy absorber 13 and the deformation A of the energy absorber 12. characteristics a ₁₂ is obtained, the characteristics a ₁₁ is obtained has been confirmed experimentally by further overall deformation. Therefore, the predetermined load F
When predetermined stroke S _{0 0,} the area of the hatched portion is the size of the absorbed energy.

[0005]

The predetermined load F ₀ is, for example, a limited value equal to or less than the proof stress of the side members of the vehicle body. Therefore, there is a problem how to increase the amount of absorbed energy, that is, the area of the hatched portion by a load smaller than the limited value.

An object of the present invention is to provide a collision energy absorbing device capable of increasing the amount of absorbed energy and a structure for mounting the collision energy absorbing device to a special place.

[0007]

According to the present invention, a plurality of cylindrical energy absorbers having different diameters are connected to each other via an annular step to form a stepped shape tapered in the axial direction. It is a collision energy absorbing device formed in the above. The smallest diameter energy absorber of the plurality of energy absorbers has at least one bead extending axially from the step to which the energy absorber is coupled.

According to the present invention, a plurality of cylindrical energy absorbers having different diameters which are adjacent to each other are connected via an annular step to form a stepped shape tapered in the axial direction. This is a collision energy absorbing device having a plurality of steps.
The plurality of steps are formed such that the width of the steps in the direction orthogonal to the axis is gradually reduced from the outer step to the inner step.

[0009] The present invention also provides a collision energy having a plurality of cylindrical energy absorbers having different diameters which are adjacent to each other and which are connected via an annular step to form a stepped shape tapered in the axial direction. In this structure, the absorbing device is attached to an object having a seat having an opening and a periphery of the opening being inclined with respect to an axis of the opening. The energy absorber having the largest diameter of the collision energy absorbing device has an inclined surface coinciding with the inclination of the seating surface, and a portion having a shortest distance from the inclined surface to a step portion closest to the inclined surface is the opening. To overhang,
Further, the collision energy absorbing device is arranged and attached so that a portion opposite to the portion comes to the seat surface.

[0010]

According to the first aspect of the present invention, the energy absorber having the smallest diameter has a bead extending in the axial direction from the step to which the energy absorber is connected, and the bead is formed in the step. Since the resistance between the bending deformation and the buckling deformation of the energy absorber having the smallest diameter is obtained, the rise of the load increases accordingly. Thereby, the amount of energy that can be absorbed by the collision energy absorbing device can be increased. In particular, since the energy absorber having the smallest diameter is first deformed by a load equal to or more than a predetermined value, it is preferable for an automobile for which a high initial load rise is desired.

According to the second aspect of the present invention, since the width of the plurality of steps is the largest on the outside and gradually decreases toward the inside, the innermost step and the energy absorber coupled to this step are provided. Is substantially equal to the resistance of the next inner step and the energy absorber coupled to this step, and in this way in turn, the load on the stroke is eventually reduced. The size becomes substantially constant, and a nearly smooth energy characteristic can be obtained.

According to the third aspect of the present invention, the position of the collision energy absorbing device is shifted from the object having the inclined seating surface, so that the largest energy absorber can be sufficiently deformed. The entire stroke amount for deformation can be increased. In addition, when the collision energy absorbing device is mounted on the seat without shifting, the load applied to the object from the shortest part of the distance from the inclined surface to the nearest step is smaller than the load applied to the object from the opposite side of the part. In some cases, the load distribution becomes substantially uniform by shifting the collision energy absorbing device.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 according to a first embodiment, a collision energy absorbing device 20 has a plurality of cylindrical energy absorbers having different diameters. In the illustrated embodiment, three energy absorbers 22, 24 and 26 having diameters adjacent to each other 2
2 and 24 are connected via an annular step portion 23, and adjacent diameter members 24 and 26 are connected via an annular step portion 25 to form an axially tapered stepped shape. The collision energy absorbing device 20 is, for example, 1.0 to 2.0.
It can be formed by deep drawing a thin iron plate of mm. A lid 28 is attached to the energy absorber 26 having the smallest diameter, and a load is input here. Each energy absorber has a truncated quadrangular pyramid shape in the illustrated embodiment, but may have another polygonal truncated pyramid shape, a truncated cone shape, a polygonal cylinder shape or a cylindrical shape. . In any case, the collision energy absorbing device 20
Has a tapered step shape, that is, the diameter of another energy absorber located on the load input side with respect to one energy absorber is smaller than the diameter of the one energy absorber. It forms so that it may become.

The smallest diameter energy absorber 26 of the plurality of energy absorbers 22, 24, 26 has at least one bead 30 extending axially from a step 25 to which the energy absorber 26 is coupled. . In the illustrated embodiment, the beads 30 are provided symmetrically on two opposing sides of the energy absorber 26, and are bulged in a semicircular shape from inside to outside. If the form is expanded outward, the bead 30 becomes a part of the step portion 25, so that the bead 30 is resistant to deformation of the step portion 25 and the load generated thereby can be increased. . However, the bead 30 may be configured to bulge inward. Further, the shape may be a triangular shape or a quadrangular shape other than the semicircular shape.

As will be described later, the load generated by the energy absorber 26 can be increased by providing the beads 30. Therefore, a bead can be provided on the energy absorber 24, which is larger in diameter than the energy absorber 26, that is, on the second stage, and on the energy absorber 22 on third stage, which is larger in diameter than the energy absorber 24. Accordingly, the load generated by the energy absorber 24 can be increased. The present invention contemplates providing a bead on the second-stage, third-stage, etc. energy absorbers, but it is essential to provide a bead on at least the first-stage energy absorber having the smallest diameter. . 2nd stage, 3rd stage
When a bead is provided in the energy absorber, it is preferable to determine the position of the bead so that its phase does not coincide with the bead of the adjacent energy absorber.

The energy absorber having the largest diameter, that is, the energy absorber 22 in the illustrated embodiment, is provided with a flange 32. The flange 32 is applied to an object to which no external load is preferably applied, for example, a front side member 34 of an automobile shown in FIG.
Then, the collision energy absorbing device 20 is attached to the front side member 34 by being inserted into the second hole 33 and screwed into the front side member 34. Front side member 34
Are important members that extend in the front-rear direction of the vehicle body on both sides of the engine room 38 of the automobile and mainly receive the rigidity in the front-rear direction, and are not preferably deformed by an external load. By attaching the collision energy absorbing device 20, the deformation can be suppressed.

When a load equal to or more than a predetermined value is applied to the collision energy absorbing device 20 via a bumper (not shown), the first-stage energy absorber 26 is bent and deformed at the step portion 25, and the whole of the energy absorber 26 tends to buckle. However, the energy absorber 26 has a bead 30 extending in the axial direction, and the bead 30 serves as a resistance against bending deformation of the step portion 25 and buckling deformation of the energy absorber 26. As a result, as shown in (c) of FIG. 1, characteristic A ₂₆ is obtained, the rising of the generated load increases. Thus, the area than a conventional bead-free characteristic A ₁₃ only hatched portion is large. Here, the reason why the characteristic A ₂₆ has a tendency to decrease after taking the peak value is that the load generated after the energy absorber 26 buckles sharply decreases. The same applies to the following stages. 1
When the energy absorber 26 of the stage is sufficiently deformed, the second stage of the energy absorber 24 is deformed bending step portion 23, also in its entirety is deformed buckling characteristics A ₂₄ is obtained. This characteristic A ₂₄
Is substantially the same as the conventional second-stage characteristic A ₁₂ (FIG. 8) since the energy absorber 24 has no bead in the illustrated embodiment. Thus, the collision energy absorbing device 2
A value of 0 increases the amount of energy that can be absorbed. In particular, the rise of the initial load is increased to increase the amount of energy.

Referring to FIG. 2 according to the second embodiment, a collision energy absorbing device 40 includes a plurality of cylindrical energy absorbers having different diameters, in the illustrated embodiment, four energy absorbers 42, 44,. Of the diameters 46 and 48, the diameters 42 and 44 adjacent to each other are arranged via the annular step 43, and the diameters 44 and 46 adjacent to each other are arranged via the annular step 45 and the diameters adjacent to each other. In this embodiment, there are a plurality of steps 43, 45, 47 formed by connecting the objects 46, 48 through an annular step 47 and forming a stepped shape tapering in the axial direction.

The plurality of steps 43, 45, 47 are formed such that the widths a, b, c in the direction perpendicular to the axis of these steps become gradually smaller from the outer step to the inner step. ing. That is, the width b of the step 45 is smaller than the width a of the step 43, and the width c of the step 47 is smaller than the width b of the step 45. Here, the width of the step portion means that when each energy absorber has a cylindrical shape or a polygonal tube shape, in other words, an energy absorber having a diameter adjacent to one energy absorber is perpendicular to the step portion. It refers to the effective width of the step when combined.
In the illustrated case, for each energy absorber is truncated pyramid shape polygonal, for example looking at the step 43, this step 43 there is an inclined portion of the horizontal portion and the width a ₂ of width a _1, The width a of the step 43 is a = a ₁ + a ₂ . Therefore,
In order for the width of the plurality of steps 43, 45, 47 to gradually decrease from the outer step to the inner step, the height of all the energy absorbers is the same, and the inclination of the steps is increased. When the angles θ _a , θ _b , and θ _c are the same, the width of the horizontal portion may be gradually reduced toward the inside. Also, the height of all energy absorbers is the same, but when the inclination angle is different, the width of the horizontal portion is made substantially the same, and θ
It should satisfy the relationship of _{a> θ b> θ c.}

When the collision energy absorbing device 40 is attached to the front side member shown in FIG. 5 and is used, if a predetermined load or more is applied to the collision energy absorbing device 40 via a bumper (not shown), the first stage energy absorbing device is used. The body 48 bends and deforms at the step 47, and the whole thereof buckles, and thereafter, the energy absorber 46 at the second stage bends and deforms at the step 45, and the whole buckles. In this way, the energy absorber gradually deforms. At this time, since the width of the step portion 47 is smaller than the width of the step portion 45, it caused a large resistance to deformation of the energy absorbing member 48 of the first stage, characteristic A ₄₈ such as FIG. 2 (b) is obtained , The rise of the generated load increases. In addition, the characteristic A ₄₈ has a relatively large rise as compared with the characteristic A ₄₆ when the energy absorber 46 in the second stage is deformed, and thus is close to the characteristic A ₄₆ . As described above, the magnitude of the load with respect to the entire stroke of the collision energy absorbing device 40 becomes substantially constant, and a nearly smooth energy characteristic can be obtained.

Referring to FIG. 3 showing a structure for attaching the collision energy absorbing device 50 to the object 60, the collision energy absorbing device 50 includes a plurality of cylindrical energy absorbers having different diameters, in the illustrated embodiment, four energy absorbers. Absorbers 52, 5
4, 56, 58 having diameters adjacent to each other,
54 are connected via an annular step 53, adjacent diameters 54 and 56 are connected via an annular step 55, and adjacent diameters 56 and 58 are connected via an annular step 57. And it is the form formed in the stepwise shape tapered in the axial direction. On the other hand, the object 60 has an opening 62, and has a seating surface 64 in which the periphery of the opening 62 is inclined with respect to the axis C of the opening. The object 60 is a front side member, a rear side member, and other rigid members of an automobile having an inclined seat surface 64.

The collision energy absorbing device 50 has the form of the collision energy absorbing device 20 shown in FIG. 1 or the form of the collision energy absorbing device 40 shown in FIG. Can be
When the mounting structure is implemented, the energy absorber 52 having the largest diameter of the collision energy absorbing device has an inclined surface 66 that matches the inclination of the seat surface 64. Then, the shortest portion 67 of the distance from the inclined surface 66 to the step portion 53 closest to the inclined surface 66 extends over the opening 62 of the object 60 by the distance x, and the opposite portion of the portion is The collision energy absorbing device 50 is arranged so as to rest on the seat surface 64 by a distance x, and is attached to the object 60 with bolts (not shown).

In a state where the collision energy absorbing device 50 is sufficiently deformed by receiving a predetermined load or more, as shown in FIG.
Then, the energy absorber 56 enters the energy absorber 54 and the energy absorber 54 enters the energy absorber 52. Then, of the energy absorber 52 having the largest diameter, a portion 67 projecting into the hole 62 of the object 60 enters the hole 62, and a portion on the opposite side is deformed. On the other hand, the collision energy absorbing device 50 having the inclined surface 66 is connected to the (c) of FIG.
As shown in FIG. 5, when the collision energy absorbing device 50 is arranged and attached to the object 60 so that the axis C ₁ of the collision energy absorbing device 50 coincides with the axis C of the hole 62 of the object 60, when the collision energy absorbing device 50 is sufficiently deformed, The energy absorber 52 having the largest diameter is not substantially deformed, and the energy absorbers other than the energy absorber 52 are deformed.
As shown by the imaginary line, the distance is almost half of the shortest portion 67 of the energy absorber 52. Therefore, according to the mounting structure of the present invention, as is apparent from FIGS. 3B and 3C, the deformation stroke of the collision energy absorbing device 50 can be increased.

A plurality of cylindrical energy absorbers having different diameters which are adjacent to each other are connected via an annular step to form a stepped shape tapered in the axial direction. For example, as shown in FIG. 4A, when four energy absorbers 72, 74, 76, and 78 form a so-called four-stage form, and the height of each energy absorber is L, the collision energy The overall height of the absorber 70 is 4L. It has been experimentally confirmed that when the collision energy absorbing device 70 is sufficiently deformed, the bottom thereof is located at an interval L / 2 from the surface of the object 80. Therefore, it can be said that the interval L / 2 does not function for energy absorption. In other words, (3L
+ L / 2) is needed for energy absorption. Therefore, as shown in FIG. 4B, if the collision energy absorbing device 90 in which L / 2 is distributed to the energy absorbers of each stage is made, the energy absorption can be effectively performed without wasting the collision energy absorbing device. it can. Now, if the height of each energy absorber after sorting the L / 2 and L _0, the relationship between the _{3L 0 + L 0/2 =} 4L, the L ₀ = 8L / 7. If the collision energy absorbing device 90 is four stages, it is preferable to set the height of each energy absorber to the L _0. Generally, in an n-stage collision energy absorbing device, L ₀ = 2 nL / (2n−1)
By doing so, it is possible to eliminate a useless interval L / 2 that does not function for energy absorption when the height of each energy absorber is L.

Using a four-stage energy absorber, a collision energy absorbing device having the beads shown in FIG. 1 attached to the first-stage energy absorber was tested, and as a result, a characteristic A shown in FIG. 6 was obtained. . On the other hand, as a result of an experiment of a beadless collision energy absorbing device made of only four stages of energy absorbers, the characteristic B of FIG. 6 was obtained. Peak value A ₁ of the characteristic A corresponding to B ₁ point characteristic B shows the effect of bead. In the second-stage energy absorber, the characteristic A generates a slightly lower load than the characteristic B. Then, the peak value A ₂ of the characteristic A corresponding to B ₂ points of the third stage of characteristic B is an effect could not be originally predicted. This is because, as shown in FIG. 7, in the collision energy absorbing device having no bead, the distance between the steps of the sufficiently deformed third energy absorber is d, whereas the bead 30 in the first stage is not. In the collision energy absorbing device marked with, since the space between the steps of the sufficiently deformed third energy absorber was reduced as d ₀ , the load drop during buckling was reduced accordingly. Conceivable.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a collision energy absorbing device according to the present invention, wherein (a) is a perspective view, (b) is a vertical sectional view of (a), and (c) shows a relationship between a load and a stroke. FIG.

FIG. 2 shows another embodiment of the collision energy absorbing device according to the present invention, wherein (a) is a cross-sectional view schematically showing (b).
FIG. 4 is a characteristic diagram showing a relationship between a load and a stroke.

3A and 3B show an embodiment of a mounting structure of a collision energy absorbing device according to the present invention, wherein FIG. 3A is a cross-sectional view schematically showing a state before deformation, and FIG. 3B is a schematic view showing a state after deformation. (C) is a cross-sectional view schematically showing a general mounting structure for comparison with the mounting structure according to the present invention.

4A and 4B schematically show a collision energy absorbing device according to the present invention, wherein FIG. 4A shows a mode in which waste occurs, and FIG. 4B shows a mode in which intervals of the waste generated in FIG. I have.

FIG. 5 is a perspective view showing a vehicle body to which the collision energy absorbing device according to the present invention can be attached.

FIG. 6 is a characteristic diagram showing an experimental result.

FIGS. 7A and 7B are cross-sectional views schematically showing deformed portions generated during the experiment of FIG. 6, in which FIG. 7A is without a bead, and FIG. 7B is with a bead.

FIG. 8 shows a conventional collision energy absorbing device,
(A) is a perspective view, (b) is a vertical sectional view of (a), (c)
FIG. 4 is a cross-sectional view schematically showing a state after deformation, and FIG. 4D is a characteristic diagram showing a relationship between a load and a stroke.

[Explanation of symbols]

20, 40, 50, 70, 90 Collision energy absorber 22, 24, 26, 28, 42, 44, 46, 48 Energy absorber 52, 54, 56, 58, 72, 74, 76, 78 Energy absorber 23 , 25, 43, 45, 47, 53, 55, 57 Step 30 bead

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60R 19/34 F16F 7/12 B62D 21/15

Claims (3)

(57) [Claims] 1. A collision energy absorbing device in which a plurality of cylindrical energy absorbers having different diameters which are adjacent to each other are connected via an annular step, and formed into a stepped shape tapered in the axial direction. Wherein the energy absorber having the smallest diameter among the plurality of energy absorbers has at least one bead extending in the axial direction from the step portion to which the energy absorber is connected. 2. A plurality of cylindrical energy absorbers having different diameters, which are adjacent to each other, are connected via an annular step, and are formed into a stepped shape tapered in the axial direction. A plurality of collision energy absorbing devices, wherein the plurality of steps are formed such that the width of the steps in a direction orthogonal to the axis is gradually reduced from the outer step to the inner step. , Collision energy absorbing device. 3. A collision energy absorbing device in which a plurality of cylindrical energy absorbers having different diameters which are adjacent to each other are connected via an annular step to form a stepped shape tapered in the axial direction. A structure having an opening, the periphery of the opening being attached to an object having a seating surface inclined with respect to the axis of the opening, wherein the largest diameter energy absorber of the collision energy absorbing device is provided on the seating surface. A slope having a slope corresponding to the slope, such that the shortest portion of the distance from the slope to the step portion closest to the slope is protruded into the opening, and a portion opposite to the portion is the seat. A mounting structure for a collision energy absorbing device, wherein the collision energy absorbing device is arranged and mounted so as to come to a surface.