JP5522114B2 - Shock absorbing member - Google Patents

Description

  The present invention relates to an impact absorbing member configured to be able to efficiently absorb an impact load by receiving and deforming the impact load at the time of a vehicle collision or the like.

Patent Document 1 discloses a technique related to an impact absorbing member configured to be deformed by receiving an impact load at the time of a vehicle collision or the like and to absorb the impact load.
As shown in FIG. 12, the impact absorbing member 100 described in Patent Document 1 includes a cylindrical housing 102 made of an aluminum alloy and a highly rigid foamed elastic body 104 housed in the housing 102. ing. The impact absorbing member 100 is used for a bumper of a vehicle, an impact beam of a door, and the like so that it can receive a collision load on the side surface of the cylindrical housing 102 and absorb the impact load and vibration energy at the time of the vehicle collision. It is configured.

Japanese Patent Laid-Open No. 2001-246995

The above-described impact absorbing member 100 is configured to receive a vehicle collision load mainly by the housing 102, and cannot receive the collision load only by the foamed elastic body 104. Therefore, when the shock absorbing member 100 is used in a high load region, it is necessary to increase the strength of the cylindrical housing 102, and the thickness of the housing 102 is increased, or the interior of the housing 102 is divided into partition walls. It is necessary to take measures such as partitioning into multiple parts. As a result, the weight of the shock absorbing member 100 is increased, and the structure is further complicated and the cost is increased.
In the above-described impact absorbing member 100, generally, when the impact absorbing member 100 is deformed by receiving an impact load, a load (initial load) at the time of starting deformation becomes larger than a load during the ongoing deformation. . For this reason, a large collision load is applied to the vehicle or the like via the shock absorbing member 100 in the early stage of the collision.

  The present invention has been made to solve the above-mentioned problems, and the problem to be solved by the present invention is to simplify the configuration of the shock absorbing member to reduce the cost and to deform the shock absorbing member. The initial load is reduced.

The above-described problems are solved by the inventions of the claims.
The impact absorbing member according to claim 1 is arranged so as to receive an impact load from an axial direction, and receives a cylindrical member that collapses in the axial direction upon receiving the impact load, and an axial direction of an annual ring is an axial direction of the cylindrical member. And the first wood whose strength against the impact load is greater than that of the tubular member, and the axial direction of the annual ring coincides with the impact load direction. A cushioning material housed in the tubular member together with the first wood, the first wood, the outer surface of the cushioning material, and the tubular shape. It has a positioning means for positioning the first wood and the cushioning material with respect to the cylindrical member so that a gap is formed over the entire circumference between the inner wall surface of the member.

According to the present invention, since the first wood has higher strength against the impact load than the cylindrical member, the impact load can be received mainly by the wood.
Furthermore, since a gap is formed between the outer surface of the first wood and the cushioning material and the inner wall surface of the tubular member, when the tubular member is crushed in the axial direction together with the first wood, The cylindrical member is easily deformed radially inward, and the cylindrical member is crushed in a bellows shape around the first wood or the like. Thereby, the 1st wood etc. are supported with good balance from the circumference by the cylindrical member crushed in the shape of a bellows, and it becomes difficult to fall down. As a result, the impact load can be efficiently received by the first wood or the like.
Thus, since the structure of the shock absorbing member is simple enough to house the first wood and the buffer material in the cylindrical member, the manufacturing cost of the shock absorbing member can be reduced.
Further, since the buffer material is set to have a lower strength against the impact load than the first wood, the buffer material is crushed with a relatively small load before the wood is crushed. For this reason, the load (initial load) at the start of crushing of the shock absorbing member can be reduced, and a large initial load is not applied to the vehicle or the like via the shock absorbing member as in the conventional case.

According to a second aspect of the present invention, the cushioning material is a first wood arranged such that the axial center direction of the annual ring intersects the impact load direction.
Here, even when the same wood is used, when the axial center direction of the annual ring intersects with the impact load direction, it is approximately compared with the case where the axial center direction of the annual ring matches the impact load direction. It becomes crushed with a load of about 1/10.
For this reason, an initial load can be reliably reduced by using the 1st wood arrange | positioned so that the axial center direction of an annual ring may cross | intersect an impact load direction as a shock absorbing material.

According to the invention of claim 3, the cushioning material is the second wood having a strength lower than that of the first wood, and is arranged such that the axial direction of the annual ring is directed to the impact load direction. To do.
For this reason, it becomes possible to use cheaper wood than the first wood.
According to the invention of claim 4, the shock absorbing material is a hard foam elastic body.
For this reason, by adjusting the expansion ratio of the hard foamed elastic body, the strength adjustment with respect to the impact load becomes easy, and the initial load can be brought close to a desired value.

According to the invention of claim 5, the length dimension of the cushioning material in the axial direction of the cylindrical member is set to about 40% or less of the length dimension of the cylindrical member in the axial direction.
According to the invention of claim 6, the positioning means is a plurality of protrusions protruding from the inner wall surface of the cylindrical member, and is arranged so as to surround the first wood and the outer surface of the cushioning material from the circumferential direction. It is characterized by.

According to the invention of claim 7, the cylindrical member is formed in a rectangular tube shape, the first wood and the cushioning material are formed in a rectangular column shape, and the size of the gap is constant. .
For this reason, a 1st wood and a cylindrical member come to be crushed equally in the circumferential direction.
According to the invention of claim 8, the cylindrical member is a molded article made of an aluminum alloy, and the first wood is cedar.
According to the invention of claim 9, when the thickness dimension of the cylindrical member is in the range of about 0.4 mm to about 1.1 mm, the gap is set to 0.5 mm or more.
Therefore, a large load can be efficiently received by the first wood and the cushioning material, and the cylindrical member is crushed into a bellows around the first wood and the like, and the wood and the like are effectively supported from around. It becomes like this.

  According to the present invention, since the structure of the impact absorbing member is simplified, the cost can be reduced and the initial load when the impact absorbing member is crushed can be reduced.

It is a schematic plan view of a vehicle front part provided with the impact-absorbing member which concerns on Embodiment 1 of this invention. It is a whole longitudinal cross-sectional view of the impact-absorbing member which concerns on Embodiment 1 of this invention. FIG. 3 is a schematic cross-sectional view taken along the line III-III in FIG. 2. FIG. 4 is a schematic cross-sectional view taken along arrow IV-IV in FIG. 2. Schematic perspective view (A diagram) showing a state in which the impact absorbing member is crushed in the axial direction by receiving an impact load, BB arrow sectional view (B diagram) of FIG. A, CC arrow sectional view of FIG. ), A and B, DD sectional view (D diagram), and B, EE sectional view (E diagram). It is the measurement data (A figure, B figure) showing the relationship between the impact load added to the said impact-absorbing member, and the crushing amount (stroke) of the said impact-absorbing member. It is a model longitudinal cross-sectional view of the impact-absorbing member which concerns on the example 1 of a change. It is measurement data showing the relationship between the impact load added to the impact-absorbing member which concerns on the example 1 of a change, and the crushing amount (stroke) of the said impact-absorbing member. It is a model longitudinal cross-sectional view of the impact-absorbing member which concerns on the example 2 of a change. 10 is a schematic cross-sectional view of an impact absorbing member according to Modification 3. FIG. 10 is a schematic cross-sectional view of an impact absorbing member according to Modification Example 4. FIG. It is a cross-sectional view of a conventional impact absorbing member.

[Embodiment 1]
Hereinafter, the impact absorbing member according to Embodiment 1 of the present invention will be described with reference to FIGS.
The X direction, the Y direction, and the Z direction shown in the figure correspond to the width direction, the height direction, and the front-rear direction of the vehicle to which the shock absorbing member is attached.

<About the mounting portion outline of the shock absorbing member 10>
The impact absorbing member 10 according to the present embodiment is a member that receives an impact load at the time of a vehicle collision and absorbs the impact load. As shown in FIG. 1, the bumper reinforcement 3 of the front bumper (not shown) and the vehicle 2 It is attached to the part of the crash box arranged between the left and right side members 5.

<About the structure of the impact-absorbing member 10>
As shown in FIGS. 2 to 4, the shock absorbing member 10 includes a tubular member 20, a wood 12 stored in the tubular member 20 with a gap S interposed therebetween, a buffer material 40, and a tubular member. 20 includes a wood 12 and positioning means 30 for positioning the cushioning material 40.
The cylindrical member 20 is installed so as to receive an impact load from the axial direction, and is configured to be crushed in the axial direction upon receiving the impact load. The cylindrical member 20 is an extruded product using an aluminum alloy, and is formed in a rectangular tube shape. Here, the thickness of the cylindrical member 20 is set to about 0.5 mm. The wall thickness is preferably set within a range of about 0.4 mm to 1.1 mm.
Here, the strength of the cylindrical member 20 in the axial direction is set to be smaller than the strength of the wood 12 and the cushioning material 40 in the axial direction.

<About the wood 12 of the shock absorbing member 10>
As shown in FIGS. 2 and 4, the wood 12 is formed in a square prism shape having a square cross-sectional shape, and the vertical (Y direction) and horizontal (X direction) dimensions of the prism are vertical of the cylindrical member 20. The value is set to a value smaller than the horizontal dimension by a certain dimension. That is, when the wood 12 is stored in the cylindrical member 20 and positioned coaxially and in phase as shown in FIG. 4, the inner wall upper surface 21u, the inner wall lower surface 21d, and the inner wall left side surface 21f of the cylindrical member 20 are arranged. In addition, gaps S of a certain size are formed between the right side surface 21r of the inner wall and the upper surface 12u, the lower surface 12d, the left side surface 12f, and the right side surface 12r of the wood 12. The wood 12 is formed in a prismatic shape so that the axial center direction of the annual ring 12k extends in the longitudinal direction (axial direction). For this reason, in a state where the wood 12 is stored in the cylindrical member 20, the axial center direction of the annual ring 12 k of the wood 12 substantially coincides with the axial direction of the cylindrical member 20. That is, the direction of the impact load at the time of collision coincides with the axial direction of the annual ring 12k of the wood 12.

<About the shock absorbing material 40 of the shock absorbing member 10>
The shock absorbing material 40 is a member having a lower strength against the collision load than the wood 12 in which the axial center direction of the annual ring 12k coincides with the direction of the impact load, and is ahead of the wood 12 with a load smaller than the wood 12. It is configured to collapse. The cushioning material 40 is the same wood as the wood 12 and is housed in the distal end portion of the cylindrical member 20 so that the axial center direction of the annual ring 12k intersects the direction of the impact load. That is, the cushioning material 40 is formed in a prismatic shape having a cross-sectional shape equal to that of the wood 12, and includes an inner wall upper surface 21u, an inner wall lower surface 21d, an inner wall left side surface 21f, an inner wall right side surface 21r, and a cushioning material. Between the upper surface 41, the lower surface 42, the left side surface 43, and the right side surface 44 of the 40, gaps S having a certain size are formed.
As described above, the cushioning material 40 is positioned so that the axial center direction of the annual ring 12k intersects the direction of the impact load. It becomes about 10. In addition, as the wood 12, for example, cedar is preferably used.

Here, the length dimension of the cylindrical member 20 in the axial direction (Z direction) is set to about 70 mm, the length dimension of the buffer material 40 in the Z direction is about 10 mm, and the length of the wood 12 in the Z direction. The dimension is set to about 60mm. Further, the vertical (Y direction) and horizontal (X direction) dimensions of the buffer material 40 and the wood 12 are set to about 40 mm.
The length dimension of the cushioning material 40 may be set between about 5 mm and 25 mm, and the length dimension of the wood 12 may be set between about 65 mm and 45 mm.

<Regarding the positioning means 30 of the shock absorbing member 10>
The positioning means 30 is configured so that the cushioning material 40 and the wood 12 are coaxial and in phase with the tubular member 20 on the distal end side (left end side in FIG. 2) and the proximal end side (right side) of the tubular member 20. It is a member to be positioned. The positioning means 30 includes a buffer 40 and a hemispherical protrusion 32 that positions the wood 12 on the distal end side of the cylindrical member 20, and a clip 38 that positions the wood 12 on the proximal end side of the cylindrical member 20. Has been.
The protrusion 32 of the positioning means 30 is a protrusion that presses the tip of the buffer material 40 and the wood 12 from the circumferential direction, and has a protrusion size equal to the gap S between the tubular member 20, the buffer material 40, and the wood 12. . As shown in FIG. 3, the protrusion 32 is a central position in the width direction of each of the inner wall upper surface 21u, the inner wall lower surface 21d, the inner wall left surface 21f, and the inner wall right surface 21r of the cylindrical member 20, and As shown in FIG. 2, it is provided at two positions in the axial direction (Z direction) of a position corresponding to the cushioning material 40 and a position corresponding to the tip portion of the wood 12.

The clip 38 of the positioning means 30 is a clip that is used as a set of four pieces, and by inserting a plate having a thickness dimension equal to the gap S into the gap S between the tubular member 20 and the wood 12, the wood 12 It is comprised so that positioning of can be performed. That is, the clip 38 is a plate that sandwiches the insertion plate portion 38w inserted into the gap S between the tubular member 20 and the wood 12 and the proximal end portion of the tubular member 20 together with the insertion plate portion 38w from the thickness direction (front and back). It is comprised from the spring part 38s. And between the inner wall upper surface 21u, inner wall lower surface 21d, inner wall left side surface 21f, and inner wall right side surface 21r of the cylindrical member 20, and the upper surface 12u, lower surface 12d, left side surface 12f, and right side surface 12r of the wood 12, FIG. As shown, the wood 12 can be positioned by inserting the insertion plate portion 38w of the clip 38, respectively. In this state, each clip 38 is attached to the proximal end portion of the tubular member 20 by the spring force of the leaf spring portion 38s.
Here, the vertical (Y direction) and horizontal (X direction) dimensions of the cylindrical member 20 are set so that the clearance S between the buffer material 40 and the wood 12 is within a range of 0.8 mm to 1.3 mm. .
The dimension of the gap S is preferably set to about 0.5 mm or more.

<About the function of the shock absorbing member 10>
Next, the function of the shock absorbing member 10 will be described with reference to FIGS.
Here, FIG. 6A shows the magnitude of the impact load applied to the impact absorbing member 10 (see FIG. 2) according to the present embodiment on the vertical axis, and the amount of crushing (stroke) in the axial direction of the impact absorbing member 10. It is a graph represented on the horizontal axis. FIG. 6B shows the magnitude of the impact load and the amount of crushing (stroke) in an impact absorbing member (not shown) having a configuration in which only the wood 12 is stored in the cylindrical member 20 without using the cushioning material 40. It is a graph showing the relationship.
As shown in FIG. 6B, in the case of an impact absorbing member that does not use the buffer material 40, the vehicle 2 collides forward and an impact load is applied to the impact absorbing member from the axial direction, and the impact load is allowed. When the value H (for example, 5 to 6 × 10 ⁴ N) is exceeded, the impact absorbing member is crushed in the axial direction and the impact load is absorbed. At this time, as indicated by the arrow F0 in FIG. 6B, since the load (initial load) when the shock absorbing member starts to be crushed becomes larger than the load that continues to be crushed, the shock absorbing member at the initial stage of the collision. A large collision load is applied to the vehicle 2 through the vehicle.

However, in the shock absorbing member 10 according to the present embodiment, since the shock absorbing material 40 having a strength with respect to the impact load is about 1/10 that of the wood 12, the shock absorbing member 10 is first buffered when the vehicle 2 collides forward. The front end portion of the cylindrical member 20 surrounding the material 40 and the buffer material 40 is crushed. For this reason, as shown to F1 arrow part of FIG. 6 (A), compared with the impact-absorbing member which does not use the shock absorbing material 40, an initial load can be reduced significantly.
Further, since a gap S of about 0.8 mm to 1.3 mm is formed between the buffer material 40 and the outer surface of the wood 12 and the inner wall surface of the cylindrical member 20, FIGS. As shown in FIGS. 5D and 5E, when the cylindrical member 20 is crushed together with the cushioning material 40 and the wood 12, the cylindrical member 20 is easily deformed radially inward. The cylindrical member 20 is crushed in a bellows shape around the wood 12.

That is, at the first bending position L1 (see FIG. 5D) on the tip side of the shock absorbing member 10, for example, as shown in FIG. It deforms outward, and the left and right parts deform radially inward. Thereby, in the 1st bending position L1, the upper part and the lower part of the cylindrical member 20 swell in a mountain shape (refer FIG. 5 (B) (D)), and a left part and a right part are contacted with the outer surface of the timber 12. It becomes deformed into a groove shape (see FIGS. 5B and 5E).
Further, in the second bending position L2 located on the rear side of the first bending position L1, as shown in FIG. 5C, the upper and lower portions of the tubular member 20 are grooves until they come into contact with the outer surface of the wood 12. The left part and the right part are deformed so as to swell in a mountain shape.
In addition, the third bending position L3 located behind the second bending position L2 is deformed in the same manner as the first bending position L1, and the fourth bending position L3 located behind the third bending position L3 is changed to the first bending position L3. The second bending position L2 is deformed.
As described above, the cylindrical member 20 is crushed in a bellows shape around the wood 12 in a state where the phase is shifted by about 90 ° between the upper part, the lower part, the left part, and the right part.
Then, the cylindrical member 20 is crushed in a bellows shape around the wood 12, so that the cylindrical member 20 can prevent the wood 12 from overturning. As a result, the wood 12 is reliably crushed in the axial direction, and as shown in FIG. 6B, the impact load is absorbed by the stroke of the crushed wood 12 and the like.
In addition, when the dimension of the clearance gap S is close to zero, the cylindrical member 20 cannot be crushed in a bellows shape around the wood 12, and the cylindrical member 20 is partially split in the axial direction. As a result, the cylindrical member 20 cannot support the wood 12 in a well-balanced manner, and the wood 12 falls down in the middle and cannot efficiently absorb the impact load in the axial direction.
That is, the wood 12 corresponds to the first wood of the present invention.

<Advantages of the shock absorbing member 10 according to the present embodiment>
According to the impact absorbing member 10 according to the present embodiment, the wood 12 and the buffer material 40 are stronger in strength against the impact load than the cylindrical member 20, so that the wood 12 and the buffer material 40 can receive the impact load. become.
Furthermore, since a gap S is formed between the outer surface of the wood 12 and the cushioning material 40 and the inner wall surface of the tubular member 20, when the tubular member 20 is crushed in the axial direction together with the wood 12 and the like, The cylindrical member 20 is easily deformed radially inward, and the cylindrical member 20 is crushed in a bellows shape around the wood 12 or the like. Thereby, the wood 12 and the like are supported from the surroundings in a well-balanced manner by the cylindrical member 20 crushed in a bellows shape, and it is difficult to fall down. As a result, the impact load can be efficiently received by the wood 12 or the like.
Thus, since the structure of the shock absorbing member 10 is simple enough to house the wood 12 and the buffer material 40 in the cylindrical member 20, the manufacturing cost of the shock absorbing member 10 can be reduced.
Furthermore, since the buffer material 40 is set to have a lower strength against the impact load than the wood 12, the buffer material 40 is crushed with a relatively small load before the wood 12 is crushed. For this reason, the load (initial load) at the start of crushing of the shock absorbing member 10 can be reduced, and a large initial load is not applied to the vehicle 2 via the shock absorbing member as in the conventional case.

Further, the buffer material 40 is wood that is arranged so that the axial center direction of the annual ring intersects the impact load direction. Here, even when the same wood is used, when the axial center direction of the annual ring intersects with the impact load direction, it is approximately compared with the case where the axial center direction of the annual ring matches the impact load direction. It becomes crushed with a load of about 1/10.
For this reason, an initial load can be reliably reduced by using the wood 12 arrange | positioned so that the axial center direction of an annual ring may cross | intersect an impact load direction as a shock absorbing material. Furthermore, since the types of materials constituting the shock absorbing member 10 do not increase and the short wood 12 can be used as the buffer material 40, the yield is improved.
Moreover, since the cylindrical member 20 is formed in a square cylinder shape, the wood 12 and the buffer material 40 are formed in a prismatic shape, and the dimension of the gap S is constant, the wood 12 and the cylindrical member 20 are It will be crushed equally in the circumferential direction.
Moreover, since the cylindrical member 20 is an aluminum material having a thickness dimension of about 0.4 mm to about 1.1 mm and the gap S is set to 0.5 mm or more, a large load is efficiently applied by the wood 12 and the buffer material 40. In addition to being received, the cylindrical member 20 is crushed into a bellows around the wood or the like, and the wood 12 and the like are effectively supported from around.

<Example of change>
Here, the present invention is not limited to the above-described embodiment, and can be modified without departing from the gist of the present invention. For example, in this embodiment, the example which uses the timber 12 (cedar material) arrange | positioned so that the axial center direction of an annual ring may cross | intersect with an impact load direction as the buffer material 40 was shown. However, as shown in FIG. 7, wood having a lower strength than wood 12 (cedar wood), for example, balsa wood, is used as the buffer material 46, and the axial center direction of the annual rings is arranged along the impact load direction. It is also possible to do. Thereby, as shown to F2 arrow part of the graph of FIG. 8, an initial load can be reduced. Moreover, the cost of the impact-absorbing member 10 can be reduced by using a balsa material. That is, the balsa material corresponds to the second wood of the present invention.
Further, as shown in FIG. 9, it is possible to use a hard foamed elastic material as the buffer material 47. For this reason, by adjusting the expansion ratio of the hard foamed elastic body, the strength adjustment with respect to the impact load becomes easy, and the initial load can be brought close to a desired value.
Here, the cushioning members 40, 46 and 47 are not arranged at the tip portion of the shock absorbing member 10, but are sandwiched between the wood 12 and the wood 12, as shown in FIG. It is also possible to arrange at the position.
Furthermore, in this embodiment, the example which inserts the square columnar timber 12 and the shock absorbing material 40 with respect to the square cylindrical cylindrical member 20, and hold | maintains the dimension of the clearance gap S substantially constant was shown. However, as shown in FIG. 10, hexagonal columnar wood 12 or the like may be inserted into the rectangular tubular member 20, or as shown in FIG. 11, the rectangular tubular member 20. It is also possible to insert an elliptical columnar wood 12 or the like.

10 .... Shock absorbing member 12k ... Annual ring 12 .... Wood (first wood)
20... Cylindrical member 32... Projection (positioning means)
38... Clip (positioning means)
40 ··· Buffer material 46 ··· Buffer material (second wood)
47 ··· Buffer material S ··· Clearance

Claims (9)

A cylindrical member disposed so as to receive an impact load from the axial direction, and crushed in the axial direction in response to the impact load;
A first wood that is housed in the tubular member such that the axial direction of the annual ring is along the axial direction of the tubular member, and the strength against the impact load is greater than that of the tubular member;
A cushioning material housed in the tubular member together with the first wood, with a member having a lower strength against the impact load than the first wood whose axial direction coincides with the impact load direction;
The first wood and the buffer for the tubular member so that a gap is formed over the entire circumference between the outer surface of the first wood and the cushioning material and the inner wall surface of the tubular member. Positioning means for positioning the material;
An impact-absorbing member comprising: The shock absorbing member according to claim 1,
The shock-absorbing member, wherein the cushioning material is the first wood disposed so that the axial center direction of the annual ring intersects the impact load direction. The shock absorbing member according to claim 1,
The shock absorbing member is a second wood having a strength lower than that of the first wood, and is arranged so that an axial center direction of an annual ring is directed to the impact load direction. The shock absorbing member according to claim 1,
The shock absorbing member is a hard foam elastic body. The impact absorbing member according to any one of claims 1 to 4,
The shock absorbing member according to claim 1, wherein a length dimension of the cushioning material in the axial direction of the cylindrical member is set to about 40% or less of a length dimension of the cylindrical member in the axial direction. The impact absorbing member according to any one of claims 1 to 5,
The positioning means is a plurality of protrusions protruding from the inner wall surface of the cylindrical member, and is arranged so as to surround the first wood and the outer surface of the cushioning material from the circumferential direction. Absorbing member. The impact absorbing member according to any one of claims 1 to 6,
The shock absorbing member, wherein the cylindrical member is formed in a rectangular tube shape, the first wood and the cushioning material are formed in a prismatic shape, and the size of the gap is constant. The impact absorbing member according to any one of claims 1 to 7,
The cylindrical member is a molded product made of an aluminum alloy,
The impact absorbing member, wherein the first wood is cedar. The shock absorbing member according to claim 8,
The impact absorbing member, wherein the cylindrical member has a thickness dimension set in a range of about 0.4 mm to about 1.1 mm, and the gap is set to 0.5 mm or more.

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