JP5161727B2 - Car frame structure - Google Patents

Description

  The present invention relates to a vehicle frame structure in which strength at the time of a collision at a shape change portion of a side member of a vehicle frame such as a truck is increased.

As shown in FIG. 5, the truck vehicle frame 10 includes a pair of left and right side members 11 and a plurality of cross members 12 that are horizontally mounted between the side members 11.
The side member 11 in the illustrated example has a rectangular closed cross-sectional shape by fitting one member to the other with the channel-shaped member facing the other.
Although not shown, a large unit such as an engine is disposed in the vehicle frame 10, and suspensions and wheels having different specifications and quantities are arranged on the front and rear shafts outside the vehicle frame 10. In general, the pair of side members 11 have a shape change portion 13 in the width direction (offset) and a shape change portion 14 in the vertical direction (kick-up or kick-down).
Therefore, when the vehicle collides with an oncoming vehicle or the like when moving forward, and a compressive impact load is applied to the side member 11 of the vehicle frame 10 via a bumper or the like, such a change in the width direction or vertical direction of the side member 11 is performed. A bending moment is generated in the portions 13 and 14.
This moment deforms the shape change portion 14 (13) of the side member 11 from the solid line shape to the dotted line shape so that the change angle increases (see FIG. 6), so the length of the moment arm A increases as the deformation increases. Increases and accelerates deformation.
On the other hand, as the shape changing portions 13 and 14 of the side member 11 are deformed, the sectional area of the internal space of the member and the sectional modulus of the member are decreased.
That is, in the case of a conventional vehicle frame, when one or both of the shape change portions of each of the left and right side members is deformed at the time of a collision, the load is reduced until the deformation amount reaches a maximum of twice the length of the shape change portion. Deforms intensively.
In order to prevent such deformation at the shape change portion of the side member and further improve the energy absorption performance of the side member, it is effective to fix a reinforcement as shown in, for example, Japanese Patent No. 3804321 to the inner surface of the side member. It is known that there is.
7A to 7E show a conventional structure in which the reinforcing member 15 is fixed inside the side member 11.
However, although such a reinforcing member 15 can be expected to increase the deformation resistance of the vehicle frame and the amount of energy absorbed at the time of the collision, it will increase to the buckling start load at the initial stage of the collision, increasing the acceleration to the passenger and the room. Therefore, it is necessary to take another measure for collision safety.
Furthermore, the reinforcing member 15 requires a dedicated molding process that matches the shape of the side member 11, and not only increases the processing cost and mold cost of the parts, but also effectively improves the energy absorption of the shape change portion. In this case, since it is necessary to securely join the side member 11 such as arc welding over the entire length of the end surface of the reinforcing member 15 or spot welding over the entire contact surface with the side member 11 at a predetermined interval, assembly processing is required. There is a problem that it involves a significant increase in costs.
Japanese Patent No. 3804321 See FIGS. 4 and 5.

  The present invention was devised in view of the above circumstances, and its main problem is to increase the absorption of energy at the time of collision by fixing a reinforcing member extending substantially linearly in the shape change portion of the side member. At the same time, the amount of deformation of the shape change portion due to the compressive load in the front-rear direction is reduced to improve the collision safety.

In order to solve the problem, the invention of claim 1
In a vehicle frame structure such as a truck having a pair of left and right rectangular closed cross-sectional side members having a shape deforming portion in the width direction and a shape deforming portion in the vertical direction that are substantially symmetrical to the left and right,
A hole formed in at least one of the front and rear in the longitudinal direction of the shape changing portion in the width direction or the vertical direction;
A reinforcing member that is inserted into the hollow portion of the shape changing portion from the hole and extends linearly; and
The reinforcing member is arranged along the longitudinal direction in the hollow portion of the shape changing portion, and is fixed or restrained so as not to move in the hollow portion.
In the invention of claim 2,
The reinforcing member is characterized in that the inside of the hollow portion of the shape changing portion is slanted along the longitudinal direction.
In the invention of claim 3,
A pair of front and rear holes are provided at the front and rear of the shape changing portion or in the vicinity thereof,
The reinforcing member inserted through the pair of holes is fixed to the side member by fixing means such as welding in a state where both ends of the reinforcing member protrude from the holes.
Furthermore, in the invention of claim 4,
One hole is provided at the front or rear of the shape changing portion or in the vicinity thereof,
The length of the reinforcing member is set to the maximum length that can be arranged in the hollow of the shape deformation portion or a length close to this,
The insertion end of the reinforcing member inserted from the hole is constrained by abutting against the inner wall surface of the shape changing portion or its vicinity,
The reinforcing member is fixed to the side member by fixing means such as welding in a state where the base end of the reinforcing member protrudes from the hole.

In this invention, the reinforcing member is inserted into the hollow portion of the shape changing portion from the hole portion, and the reinforcing member is fixed or restrained in a state where the reinforcing member is slanted along the longitudinal direction of the shape deforming portion. The shape change part of the side member can be reinforced.
In addition, since the reinforcing member is fixed in the hollow portion of the shape changing portion, when an impact load is applied to the front end portion of the side member, the initial deformation when the buckling is started by the compressive load in the front-rear direction is different from the conventional structure. However, the deformation resistance does not drop compared with the conventional structure from the middle to the later stage of deformation, and the impact can be absorbed with a small amount of deformation.
The energy applied at the time of the collision of the oncoming vehicle can be absorbed with a small deformation amount of the shape change portion of the side member.
Thereby, the shortening of the distance before and after the shape changing portion can be suppressed, and this greatly suppresses the reduction of the living space in the vehicle, so that the safety in the vehicle can be improved.

  According to the present invention, the safety of the vehicle is improved by fixing the reinforcing member in the hollow portion of the shape changing portion in the width direction or the vertical direction by the side member of the vehicle frame.

Hereinafter, a preferred embodiment when the vehicle frame structure of the present invention is applied to a vehicle frame of a truck will be described with reference to the drawings.
As in the conventional structure of FIG. 5, the vehicle frame has a pair of left and right side members 1 having a rectangular closed cross-sectional shape, and a cross member (not shown) horizontally mounted between the side members 1 and 1. Each of the members 1 and 1 has a shape change portion (offset shape portion) 3 in the width direction and a shape change portion (kick-up shape portion and kick-down shape portion) 4 in the vertical direction that are substantially symmetrical to the left and right.

In the first embodiment, as shown in FIGS. 1A and 1B, a hole 6 for inserting the reinforcing member 5 into the hollow portion 3A or 4A in front of and behind the shape changing portion 3 or 4 is used. , 6 are drilled in advance.
Here, the front and rear are not limited to the region of the shape changing portion 3 or 4 but also include neighboring positions outside the region.

In the shape changing portion 3 in the width direction of the side member 1 shown in FIG. 1A, a reinforcing member 5 is stretched over the hollow portion 3A so as to cross the hollow portion 3A obliquely along the longitudinal direction. .
Here, the reinforcing member 5 is arranged so as to cross obliquely along the longitudinal direction of the hollow portion 3A, but the inclined posture of the reinforcing member 5 is preferably arranged along the diagonal line of the hollow portion 3A.
In the present invention, the reinforcing member 5 may pass through the hollow portion 3 without being inclined at the hollow portion 3A.

  Also in the shape change part (kick-down shape part in the figure) 4 in the vertical direction of the side member 1 shown in FIG. 1B, the hollow part 4A is placed in the longitudinal direction in the hollow part 4A of the vertical shape change part 4 The reinforcing member 5 is stretched so as to cross diagonally along.

Here, the reinforcing member 5 may be parallel to the center line of the hollow portion 4A or cross the center line as long as the reinforcing member 5 is disposed obliquely from one to the other in the vertical direction of the side member 1. It may be along a diagonal line.
Further, when the shape change portion changes not only in the vertical direction but also in the width direction, the reinforcing member 5 is preferably arranged along one of the diagonal lines of the hollow portion of the shape change portion.

  In the present embodiment, the reinforcing member 5 is a metal pipe that extends in a straight line. However, a metal pipe, bar, plate, or the like having an arbitrary cross-sectional shape such as a circle or a corner can be used.

The reinforcing member 5 is inserted into the hollow portion 3A or 4A of the shape changing portion 3 or 4 from the outside so that both end portions 5a and 5b protrude from the hole portions 6 and 6, respectively.
Then, the front end 5 a and the rear end 5 b of the reinforcing member 5 protruding from the holes 6, 6 are joined to the outer wall of the side member 1 by welding or the like while closing the holes 6.
Reference numeral 7 denotes the joint.

  Thereby, when an impact load is applied to the front end portion of the side member 1 and the shape changing portion 3 or 4 is deformed as shown in FIG. The shortening amount B of the distance before and after the shape changing portion 3 or 4 of the member 1 acts so as to be suppressed by the reinforcing member 5 incorporated in the hollow portions 3A and 4A.

  An example of a general pickup truck in which a vehicle frame including a side member having a flat cross section is used as an example, an announcement that specifies the standards of Article 18 paragraph 3 of road transport vehicle safety standards and details of road transport vehicles, and attachments An analysis of the front part of the vehicle frame as shown in FIG. 3 was performed which approximated an offset collision test in accordance with 104 (technical standard for occupant protection during offset collision).

As a result, as shown in FIG. 4, it was confirmed that there is no difference in impact performance such as maximum load at the initial stage of deformation when buckling starts, as compared with the conventional product.
This indicates that the acceleration of each part of the passenger and the vehicle interior does not change at all, and there is no problem in the safety of the room.

On the other hand, when the deformation amount of the car frame is about 200 mm to about 500 mm in the late stage of the collision, the deformation resistance of the example does not drop as much as the conventional product, and the impact energy absorption amount, which is the area of these graphs, is finally compared with the conventional product. Increase by about 30%.
This indicates that the same collision energy can be absorbed with a small deformation amount. For example, if the conventional collision energy is a deformation amount of 500 mm, it can be absorbed with a deformation amount of 350 mm and 30% less in the embodiment.

From this, if it is a reinforcing member having the shape used in this analysis, assuming that the deformation amount of the front end portion of the side frame is proportional to the decrease of the living space in the vehicle, the amount of change in the living space can be greatly suppressed by this embodiment. Easy to estimate.
The cross-sectional area of the reinforcing member required for this is about 25% of the average cross-sectional area of the side member, which may be lighter than about 25% to 40% of the reinforcing member used in the conventional product. It won't be heavy.

   As shown in FIG. 1, the above-mentioned effect is confirmed by checking that the thickness of the side member 1 is 0.05 L when the side member 1 is L and the length is 2 L. The length in the direction was 9L, the length in the horizontal direction of the shape changing portion 4 in the vertical direction was 7L, and the reinforcing member 5 was a metal pipe having a diameter of 0.5L.

As long as the buckling start load is not increased, the reinforcing member 5 can use a reinforcing member having a larger cross-sectional shape and thickness, and if the acceleration of each part at the time of collision has a margin, it is larger than this. It is possible to use a reinforcing member.
In this case, it is possible to further increase the collision absorption energy at the same deformation amount, that is, to further suppress the deformation amount of the vehicle frame after absorbing the collision energy and to secure a larger occupant living space.

In the vehicle frame structure of Embodiment 2 shown in FIG. 2, one end of the reinforcing member 5 is joined to the side member 1 by welding or the like, and the other end is constrained and fixed in the hollow portion of the shape changing portion 3 or 4. ing.
The length of the reinforcing member 5 is set to a maximum length that can be arranged in the hollow portion 3A or 4A of the shape changing portion 3 or 4 or a length close thereto.
Other configurations are the same as those of the first embodiment.

That is, also in the shape change portion 3 in the width direction of the side member 1 shown in FIG. 2A, the hollow portion 3A crosses the hollow portion 3A obliquely along the longitudinal direction in the hollow portion 3A of the shape change portion 3 in the width direction. Thus, the reinforcing member 5 is stretched over.
2B, the shape change portion 4 in the vertical direction of the side member 1 (in the drawing, the kick-down shape portion) 4 has the hollow portion 4A elongated in the hollow portion 4A of the shape change portion 4 in the vertical direction. The reinforcing member 5 is stretched so as to cross obliquely along the direction.

In the second embodiment, the reinforcing member 5 is set to a maximum length that can be disposed obliquely through the hollow portion 3A or 4A as described above, or a length close thereto.
Therefore, the degree of freedom of the position of the reinforcing member 5 is restrained by interfering with the inner wall surface of the side member 1 before the buckling deformation of the side member 1 or before the buckling deformation of the side member 1.

  In the second embodiment, a hole 6 is formed in front of the reinforcing member 5 with a large degree of freedom, either before or after the shape changing portion 3 or 4, and the reinforcing member 5 is shaped from the hole 6. The insertion tip 5b is abutted against the inner wall surface of the side member 1 or is inserted to the abutting position 8 just before it. The insertion base end 5a is inserted into the hole 6 and the side member 1. The joint portion 7 is formed by being fixed to the outer wall surface by welding or the like.

In the vehicle frame structure of the second embodiment, the reinforcing member 5 extends slightly, so that the weight is slightly increased as compared to the first embodiment, but the component cost of the reinforcing member 5 does not increase compared to the conventional reinforcement. Further reductions in assembly costs can be expected.
In the structure of the second embodiment, the base end side of the reinforcing member 5 is fixed to the side member 1 by welding or the like, and the insertion tip is fixed from the beginning by interfering with the inner wall surface of the side member 1 or is initially buckled. Since it is fixed by interfering with the inner wall surface of the side member 1, the same effects as those of the first embodiment can be obtained.
In addition, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the scope of the invention.

(A) is explanatory drawing seen from the plane which shows the attachment structure of the shape change part of the width direction, and the reinforcement member of Example 1, (b) is seen from the side which shows the attachment structure of the shape change part and reinforcement member of an up-down direction. FIG. (A) is explanatory drawing seen from the plane which shows the attachment structure of the shape change part of the width direction, and the reinforcement member of Example 2, (b) is seen from the side which shows the attachment structure of the shape change part and reinforcement member of an up-down direction. FIG. It is a schematic diagram explaining an offset collision test. It is a graph which shows the result of the offset collision test which compared the conventional product and the Example. It is a perspective view which shows a vehicle frame. It is a principal part side view which shows a deformation | transformation of the shape change part at the time of a collision. (A) Cross-sectional view of a side member provided with a conventional reinforcing member, (b) Cross-sectional view of a side member provided with a different conventional reinforcing member, (c) Cross-sectional view of a side member provided with another conventional reinforcing member (D) It is sectional drawing of the side member which provided another conventional reinforcement member, (e) It is sectional drawing of the side member which provided the reinforcement as a reinforcement member.

Explanation of symbols

1 Side member 3 Width direction shape change part (offset shape part)
4 Vertical shape change part (kick-up shape part, kick-down shape part)
DESCRIPTION OF SYMBOLS 5 Reinforcement member 6 Hole part 7 Joint part 8 Abutting position K Welding 10 Car frame 11 Side member 12 Cross member 13 Shape change part 14 in the width direction Vertical shape change parts 15 and 16 Reinforcement member

Claims (4)

In a vehicle frame structure such as a truck having a pair of left and right rectangular closed cross-sectional side members having a shape deforming portion in the width direction and a shape deforming portion in the vertical direction that are substantially symmetrical to the left and right,
A hole formed in at least one of the front and rear in the longitudinal direction of the shape changing portion in the width direction or the vertical direction;
A reinforcing member that is inserted into the hollow portion of the shape changing portion from the hole and extends linearly; and
A vehicle frame structure characterized in that the reinforcing member is disposed along a longitudinal direction in a hollow portion of a shape changing portion, and is fixed or restrained so as not to move in the hollow portion.   The vehicle frame structure according to claim 1, wherein the reinforcing member is formed by slantingly passing through the inside of the hollow portion of the shape changing portion along the longitudinal direction. A pair of front and rear holes are provided at the front and rear of the shape changing portion or in the vicinity thereof,
3. The reinforcing member inserted through the pair of holes is fixed to the side member by fixing means such as welding in a state where both ends of the reinforcing member protrude from the holes. Car frame structure. One hole is provided at the front or rear of the shape changing portion or in the vicinity thereof,
The length of the reinforcing member is set to the maximum length that can be arranged in the hollow of the shape deformation portion or a length close to this,
The insertion end of the reinforcing member inserted from the hole is constrained by abutting against the inner wall surface of the shape changing portion or its vicinity,
The vehicle frame structure according to claim 1 or 2, wherein the reinforcing member is fixed to the side member by a fixing means such as welding in a state where the base end of the reinforcing member protrudes from the hole.

Images