JPH0679615U - Impact protection beam for vehicle door - Google Patents

Abstract

(57) [Abstract] [Purpose] By constructing the main body by joining steel plates so as not to cause warping and strength reduction in the impact protection beam disposed inside the vehicle door to reinforce it, Make it lightweight and inexpensive to manufacture. [Structure] A steel plate 18 is rounded into a substantially cylindrical shape, and the main body 12 of the impact protection beam 10 is formed by laser welding at three positions where the long side parts 20 and 22 are butted against each other, which is less adversely affected by welding heat. ,
The laser welded joints 24a to 24c are fixed to the door via the pair of mounting portions 14 and 16 in a posture in which the joints 24a to 24c face outward of the vehicle.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an impact protection beam disposed inside a vehicle door to reinforce the door.

[0002]

[Prior art]

 The inside of the door that constitutes the side of a vehicle such as a passenger car is designed to prevent deformation of the door in the direction of the depression against the impact load applied from the side of the vehicle during a side collision. A reinforcing member called an impact protection beam may be arranged substantially parallel to the front-rear direction of the vehicle. A type of such impact protection beam is a main body in which steel plates forming a long shape are rolled into a substantially cylindrical shape and integrally joined by arc welding, and the main body is provided at both ends in the longitudinal direction of the main body. It is considered to have a pair of mounting portions for integrally fixing the main body to the door in a posture in which the applied joint portion faces the outside of the vehicle. The impact protection beam of the vehicle door described in Japanese Patent Application No. 4-84990 filed earlier by the present applicant is one example thereof, and a configuration intended for cost reduction and weight reduction is disclosed. .

[0003]

[Problems to be solved by the device]

 However, when the steel plates are joined by arc welding as in the above impact protection beam, it is inevitable that warpage occurs in the longitudinal direction due to contraction of the heated portion during arc welding. For this reason, it is necessary to correct the warp after arc welding, or to set the shape that allows for the warp in advance to mold the main body, and there is a problem that the cost increases accordingly. Also, the strength of the base metal decreases near the weld due to the heat effect of arc welding, so the strength of the entire impact protection beam becomes lower than the required strength. To compensate for this, it is necessary to take measures such as increasing the plate thickness, but then there was the inconvenience that the weight increased.

The present invention has been made in view of the above circumstances. The purpose of the present invention is to construct a main body by joining steel plates so as not to cause warpage and strength reduction, so that it is light and inexpensive. To provide a high impact protection beam.

[0005]

[Means for Solving the Problems]

 In order to achieve such an object, the gist of the present invention is that it is disposed inside the door that constitutes the side surface of the vehicle in the vehicle front-rear direction, and a shock load is applied to the door from the side of the vehicle when a side collision occurs. An impact protection beam that suppresses the deformation of the door when added, in which (a) a steel plate having a longitudinal shape is rolled into a substantially cylindrical shape and integrally joined by laser welding. b) A pair of mounting portions that are provided at both longitudinal ends of the main body and integrally fix the main body to the door in a posture in which the laser-welded joints face outward of the vehicle. Especially.

[0006]

[Effect of action and device]

 The impact protection beam of such a vehicle door is fixed to the door through a pair of mounting parts in a posture in which the joint portion of the main body, which is laser-welded, faces outward of the vehicle. When an impact load is applied to the door from the side of the vehicle, deformation of the door can be effectively prevented by the deformation resistance of the main body. Here, since the main body is formed by rolling a long steel plate into a substantially cylindrical shape and integrally joining them by laser welding, as in the case of joining by arc welding with a relatively wide heating range, There is no warpage in the longitudinal direction due to shrinkage, and the strength of the base metal does not decrease near the weld. Therefore, it is not necessary to correct the warp after welding, set and shape the shape in anticipation of the warp, or take measures to increase the plate thickness to compensate for the decrease in strength.The impact protection beam is lightweight and inexpensive while ensuring the required strength. Can be configured to.

Further, the bead of the laser welded portion has a smaller protrusion amount than the bead in the case of arc welding and protrudes to the outer peripheral side of the main body, and the installation space in the door is accordingly reduced, which is advantageous in design. .

[0008]

【Example】

 An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view of an impact protection beam (hereinafter, simply referred to as an impact protection beam) 10 for a vehicle door, which is an embodiment of the present invention. The impact protection beam 10 includes a body 12 and a pair of mounting portions 14 and 16 provided at both ends in the longitudinal direction of the body 12 integrally formed from a steel plate (blank) 18 punched into a predetermined shape shown by a chain line in the figure. It is composed. FIG. 2 shows a cross section of the intermediate portion 12a of the main body 12 which is perpendicular to the longitudinal direction.

The steel plate 18 having a longitudinal shape is rounded into a substantially cylindrical shape by pressing the long side portions 20 and 22 on both sides in the portion corresponding to the main body 12 along the longitudinal direction by pressing. . Both end portions 12b and 12c of the main body 12 near the mounting portions 14 and 16 are changed in a state that the width dimension of the steel plate 18 is sharply constricted, and the end portion is bifurcated by being bent flat from a cylindrical state. Is processed into a branch shape and has a shape that smoothly changes to the mounting portions 14 and 16 having a width dimension larger than that of the intermediate portion 12a. On the other hand, the portions corresponding to the mounting portions 14 and 16 are bent at a right angle to the longitudinal direction and are bent in a stepwise manner. After that, laser welding is applied to the abutting portions of the long side portions 20 and 22 from the outside to the central portion and both end portions in the longitudinal direction, so that the long side portions 20 and 22 are joined at three joining portions 24a, 24b, and 24c. (Hereinafter, unless otherwise specified, simply referred to as a joint 24), they are integrally joined and joined together to form the component shape shown by the solid line in FIG. The laser welding described above is performed by a welding robot or the like on the main body 12 which has been previously positioned by a jig or the like in an automatic welding line or the like, but the laser heat source is extremely excellent in light converging property and irradiation controllability. In addition, since the heating time is very short, the heating range is narrower than that in arc welding, and the warp in the longitudinal direction of the main body 12 and the deterioration of the strength of the base material due to the influence of heat hardly occur.

As shown in FIG. 3, which is a cross section perpendicular to the vehicle front-rear direction, the pair of mounting portions 14 and 16 are provided when the impact protection beam 10 is disposed between the inner panel 28 and the outer panel 30 of the door 26. The shapes of these are determined so that the main body 12 can be integrally fixed to the door 26 in a posture in which the laser-welded joint 24 faces outward of the vehicle. It is fixed to the door frame. Further, when the impact protection beam 10 of this embodiment is arranged in the door 26, the amount of protrusion of the weld bead at the joint portion 24 to the outer peripheral side of the main body 12 is smaller than that of the bead by arc welding. The space is wide and the design is easy.

As the steel plate 18, a high-tensile steel plate having a tensile strength of 100 kgf / mm ² or more and a plate thickness of about 1.4 to 2.6 mm can be used. Further, the diameter of the cylindrical shape of the main body 12 is approximately 25 to 32 mm and is substantially constant over the entire length of the intermediate portion 12a. In the case of this embodiment, the welding length Wa of the central joint portion 24a is approximately 300 mm and both ends are The welding lengths Wb and Wc of the joints 24b and 24c are about 100 mm, and the distance between the joints 24a and 24b and 24c is about 100 mm. The above-mentioned welding lengths Wa, Wb, Wc are predetermined in order to suppress the welding cost within a range in which the required bending strength and impact force absorption performance are sufficiently obtained, and are appropriately changed as necessary. It

In the door 26 to which such an impact protection beam 10 is attached, if a shock load is applied from the side of the vehicle, that is, from the right side of FIG. 26 tends to be deformed so as to be recessed toward the inner side of the vehicle, that is, to the left side in FIG. 3, at the central portion in the vehicle front-rear direction. However, the impact load is received by the impact protection beam 10 to reduce the degree of deformation. To be done. In that case, at the joint portion 24 of the main body 12 facing the outside of the vehicle, the action of the welding joining, that is, the welding bead of the laser welding makes it a little thicker than other portions, and the mother portion due to the heat influence. Since the strength of the material is not reduced, it is possible to properly receive the impact load from the side of the vehicle, suppress the deformation due to the impact load, and absorb the impact force.

Here, the impact protection beam 10 of the present embodiment and a conventional impact protection beam (not shown) having a main body joined by arc welding (the blank before processing is the same as the steel plate 18, The results of the bending test conducted by the present inventors will be described using a thickness of 140 kgf / mm ² , a plate thickness of 1.6 mm, and a body diameter of 32 mm, which is equal to that of the body 12. FIG. 4 is a diagram for explaining the outline of the bending test apparatus, in which each impact protection beam is placed on the pair of support members 32 and 34, and the pressing metal fitting 36 is pressed against the central portion thereof from above to thereby The displacement in the portion, that is, the relationship between the lowered position of the pressing member 36 and the applied load is measured. The span S between the pair of support members 32 and 34 is 750 mm, the radius of curvature R of the contact surface of the pressing member 36 is 152 mm, and the load speed, that is, the descending speed of the pressing member 36 is 20 mm / min. In addition, each impact protection beam was subjected to a bending test with the side facing outward when mounted on the door, that is, the welded joint facing upward.

FIG. 5 is a diagram showing the results of the bending test, in which the solid line a is the data of the impact protection beam 10 of this embodiment, and the broken line b is the data of the conventional impact protection beam by arc welding. As is clear from the test results, the impact protection beam 10 of the present embodiment has a larger load load until reaching the elastic limit and a displacement that is substantially equal to that of the conventional product, and is excellent in both bending strength and impact absorption characteristics. You can see that

As described above, the impact protection beam 10 of this embodiment has the largest bending strength with respect to the force acting from the joint portion 24 side, and the impact load is applied from the side of the vehicle to the door 26 when a side collision occurs. When it is added to the door 26, the deformation of the main body 12 can prevent the deformation of the door 26. Here, since the main body 12 is formed by rolling a long steel plate 18 into a substantially cylindrical shape and integrally joining them by laser welding, as in the case of arc welding having a relatively wide heating range, The warp does not occur in the longitudinal direction due to the heat shrinkage of the base metal, and the strength of the base metal does not decrease in the vicinity of the welded part 24. Therefore, it is not necessary to take measures for increasing the plate thickness to compensate for the decrease in strength. As a result, the impact protection beam 10 is manufactured at a low cost while ensuring the required strength.

Further, the welding bead at the joint portion 24 has a smaller protrusion amount than the bead in the case of arc welding and protrudes toward the outer peripheral side of the main body 12, and the disposing space in the door 26 becomes smaller accordingly. It will be advantageous.

Further, since the main body 12 formed by rolling the steel plate 18 can freely set its shape, the both end portions 12b, 12b, which are close to the mounting portions 14, 16 and do not require a large bending strength, are provided. 12c is flattened and plate-shaped, and in this respect as well, the weight and cost are reduced.

Further, in manufacturing the main body 12, the steel plate 18 is rolled into a cylindrical shape by press working, and the butted portion of the cylindrical shape may be laser-welded from the outside by a welding robot or the like, which is simple and inexpensive. Can be manufactured.

Further, the main body 12 and the mounting portions 14 and 16 in the present embodiment are integrally formed by press forming mainly of bending work from a single steel plate 18, and the main body 12 and the mounting portions 14 and 16 are integrated. Since there is no need to carry out the work of changing the structure and the manufacturing process is simplified, there is an advantage that the impact protection beam 10 can be manufactured at low cost.

Although one embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in other modes.

For example, in the above-described embodiment, the pair of long side portions 20 and 22 of the steel plate 18 rounded into a cylindrical shape are butted and the butted portion is laser-welded. Like the impact protection beam 40 shown, a part of the long side portions 44, 46 of a steel plate 48 having a width dimension larger than that of the steel plate 18 are overlapped, and laser welding is applied to the overlapped portion, whereby the main body 42 is formed. May be formed in a cylindrical shape.

Further, in the above-described embodiment, the main body 12 of the impact protection beam 10 and the pair of mounting portions 14 and 16 are integrally formed from the steel plate 18, but they are divided into a plurality of individual products. It is also possible to configure it by, for example, forming a substantially cylindrical main body from a substantially rectangular steel plate by laser welding, and welding a pair of brackets separately prepared as attachment parts to both ends of the main body by welding. May be.

Further, although the cylindrical shape of the main body 12 in the above-described embodiment has a constant diameter in the intermediate portion 12a, the both end portions 12b, 12c are depending on the installation space in the door 26, the required bending strength and the like. Alternatively, the main body 12 may be rounded into a spindle shape whose diameter is gradually changed in the longitudinal direction.

Further, in the above-described embodiment, the long side portions 20 and 22 are joined at the three joining portions 24a, 24b and 24c by laser welding the central portion and both end portions in the longitudinal direction. However, it does not matter if laser welding is performed over the entire range of the butted portion, and the welding lengths Wa, Wb, Wc and the number of welded portions (joint portions) of each portion depend on the required bending strength and It may be appropriately changed depending on the impact absorption performance and the like.

Further, the material and thickness of the steel plate 18, the cylindrical diameter dimension of the main body 12 and the shapes of the both end portions 12b and 12c and the mounting portions 14 and 16 in the above-described embodiment are required to meet required bending strength and the like. Of course, it can be appropriately changed according to the above.

Although not illustrated one by one, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a perspective view showing an impact protection beam of a vehicle door according to an embodiment of the present invention.

FIG. 2 is a sectional view of the impact protection beam of FIG. 1 at right angles to the longitudinal direction of the main body.

FIG. 3 is a sectional view of the impact protection beam of FIG. 1 when the impact protection beam is installed in a door and is perpendicular to the vehicle front-rear direction.

4 is a diagram illustrating an outline of an apparatus for performing a bending test of the impact protection beam of FIG.

FIG. 5 is a diagram showing the bending test results of the impact protection beam of FIG. 1 in comparison with a conventional product by arc welding.

FIG. 6 is a cross-sectional view of a main body showing a state in which both sides of steel sheets are overlapped and laser-welded to each other in another embodiment of the present invention.

[Explanation of symbols]

10, 40: Impact protection beam of vehicle door 12, 42: Main body 14, 16: Mounting portion 18, 48: Steel plates 24a, 24b, 24c: Joining portion 26: Door

Claims (1)

[Scope of utility model registration request] 1. A door, which is disposed inside a door constituting a side surface of a vehicle, in the front-rear direction of the vehicle and suppresses deformation of the door when an impact load is applied to the door from the side of the vehicle during a side collision or the like. In the impact protection beam, a steel body having a longitudinal shape is rounded into a substantially cylindrical shape and integrally joined by laser welding, and the main body is provided at both ends in the longitudinal direction of the body. And a pair of mounting portions for integrally fixing the main body to the door in a posture in which the joint portion faces the outside of the vehicle.