JP2006248328A - Vehicle body structure member and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lightweight vehicle body structure member having sufficient strength and moldability. <P>SOLUTION: The vehicle body structure member 40 applied with bending load has a cylindrical side wall 41 and wire materials 47, 48, 49 joined to the side wall 41. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle body structural member and a method for manufacturing the same.

  Body structure members that are subjected to bending load are manufactured by applying hydraulic forming to a tubular material, for example, and by increasing the strength of the material or increasing the plate thickness of the material, the member strength against the load is increased. Has improved.

  However, improving the strength of the material has a problem of deteriorating moldability, and it is difficult to form the material into a desired shape. Moreover, since the increase in the thickness of the material is accompanied by an increase in the weight of the manufactured product, it has a problem of deteriorating the vehicle power performance.

  The present invention has been made to solve the problems associated with the prior art, and an object of the present invention is to provide a lightweight vehicle body structural member having good strength and formability and a method for manufacturing the same.

In order to achieve the object, the invention according to claim 1 provides:
A vehicle body structural member on which a bending load acts,
A cylindrical side wall, and
A vehicle body structural member having a wire joined to the side wall.

The invention according to claim 7 for achieving the object is as follows.
A method of manufacturing a tubular vehicle body structure member on which a bending load acts,
A joining process for joining a wire to a flat material,
A bending process for forming a hollow preform by applying bending to the material to which the wire is bonded and bonding the end faces; and
A hydraulic forming step for forming a cylindrical hydraulic molded product corresponding to the vehicle body structural member by applying a hydraulic pressure to the interior of the preform and causing the preform to bulge;
In the manufacturing method, the wire is positioned in the joining step so as to be arranged on a cylindrical side wall of the hydroformed product.

  The present invention configured as described above has the following effects.

  According to the first aspect of the present invention, the wire joined to the side wall of the vehicle body structural member reinforces the strength. Therefore, it is possible to withstand a larger load with respect to the input of the bending load without increasing the strength of the side wall material, and deterioration of the formability of the side wall material can be suppressed. Moreover, since the wire is locally disposed, it is possible to suppress an increase in the weight of the manufactured product and a deterioration in the vehicle power performance as compared with the case where the thickness of the side wall material is increased. That is, it is possible to provide a light-weight vehicle body structural member having good strength and formability.

  According to invention of Claim 7, it is possible to manufacture the vehicle body structural member which has the wire joined to the cylindrical side wall. Since the wire reinforces the strength, it can withstand a larger load with respect to the input of the bending load without increasing the strength of the side wall material, and can suppress the deterioration of the formability of the side wall material. it can. Further, since the wire is locally disposed, it is possible to suppress an increase in the weight of the manufactured member and a deterioration in the vehicle power performance as compared with the case where the thickness of the sidewall material is increased. That is, it is possible to provide a method for manufacturing a light-weight vehicle body structural member having good strength and formability.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 and 2 are a perspective view and a cross-sectional view for explaining a vehicle body structural member according to an embodiment of the present invention.

  The vehicle body structural member 40 is applied to a cylindrical (hollow) component that constitutes an automobile body such as a member or a pillar to which a bending load acts. The acting direction of the load is an intersecting direction Y substantially orthogonal to the axial direction X of the vehicle body structural member 40.

  The cylindrical side wall 41 of the vehicle body structural member 40 has a substantially rectangular cross section and has four side wall surfaces 42 to 45. The side wall surfaces 42 and 43 are substantially perpendicular to the load input direction, and the side wall surfaces 42 constitute a load input surface. The side wall surfaces 44 and 45 are substantially perpendicular to the side wall surfaces 42 and 43 and constitute a surface substantially parallel to the load input direction.

  The material of the side wall 41 is not particularly limited as long as it has an appropriate strength. For example, a metal plate made of steel, an aluminum alloy, a magnesium alloy, or the like is applicable.

  The vehicle body structural member 40 includes wire rods 47 to 49 joined to the side wall 41. It is preferable that the wire rods 47 to 49 have relatively higher strength than the side wall material. For example, a high-strength wire rod such as a carbon fiber or a piano wire, or a metal wire can be applied. The method for joining the wires 47 to 49 is not particularly limited, but welding is preferable because joining is easy.

  The wire 47 is juxtaposed on the inner surface of the side wall surface 42, is positioned along the axial direction X, and is substantially perpendicular to the crossing direction Y that is substantially parallel to the load input direction. The wire rods 48 and 49 are juxtaposed on the inner surfaces of the side wall surfaces 44 and 45, positioned along the intersecting direction Y, and substantially parallel to the load input direction.

  Since the wires 47 to 49 reinforce the strength of the vehicle body structural member 40, the wire rods 47 to 49 can withstand a larger load with respect to the input of the bending load without increasing the strength of the side wall material. Can be suppressed.

  Moreover, since the wire rods 47 to 49 are locally (partially) arranged, the weight of the manufactured product (vehicle body structural member) 40 and the vehicle power performance are improved as compared with the case where the thickness of the side wall material is increased. Deterioration can be suppressed. For example, even when the thickness of the side wall material is reduced, the strength comparable to that of the conventional vehicle body structural member can be ensured, so that the vehicle body structural member can be reduced in weight.

  In the present embodiment, three wire rods 47, 48, and 49 are disposed on the side wall surfaces 42, 44, and 45, respectively. However, the arrangement direction, the number of arrangements, the arrangement surface, and the like can be appropriately changed as necessary. For example, the wire rods 47, 48, and 49 can be disposed on the outer surface of the side wall 41 as necessary.

  Next, a method for manufacturing the vehicle body structural member 40 will be described. 3 is a perspective view for explaining a joining process, FIG. 4 is a perspective view for explaining a bending process following FIG. 3, and FIG. 5 is a hydraulic forming apparatus according to an embodiment of the present invention. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5, FIG. 7 is a cross-sectional view for explaining the hydraulic forming step following FIG. 4, and FIG. It is a perspective view for demonstrating the hydraulic pressure molded product produced from a shaping | molding process.

  The manufacturing method of the vehicle body structural member 40 includes a joining process, a bending process, and a hydraulic forming process.

  In the joining step, as shown in FIG. 3, the wires 17 to 19 are joined to one surface 11 of the plate material (sidewall material) 10 that constitutes the side wall 41 of the vehicle body structural member 40.

  The wire rods 17 to 19 constitute the wire rods 47 to 49 joined to the side wall 41. Therefore, the wire rod 17 is arranged in parallel to the approximate center of the plate member 10, and the wire rods 18 and 19 are arranged in a direction substantially perpendicular to the arrangement direction of the wire rod 17 with the portion to which the wire rod 17 is joined. . Since the wires 17 to 19 are joined to the plate member 10 instead of the cylindrical member, the joining work is easy.

  In the bending process, as shown in FIG. 4, a hollow shape having a substantially circular cross section is obtained by bending the plate member 10 to which the wire rods 17 to 19 are bonded and bonding the end surfaces 13 and 14. The preform 20 is formed.

  At this time, the bending direction is controlled so that the surface 11 to which the wire rods 17 to 19 are joined faces inward. Since no wire is joined to the outer surface 12 of the plate member 10, the outer surface of the preform 20 has no protrusions and is smooth. If necessary, the bending direction can be changed to the opposite direction, and the surface 11 to which the wires 17 to 19 are joined can be set to face the outside.

  The bending process is, for example, roll forming. The joining of the end faces 13 and 14 is, for example, butt laser welding.

  In the hydraulic molding step, a cylindrical hydraulic molded product 30 corresponding to the vehicle body structural member 40 is formed by applying a hydraulic pressure to the inside of the preform 20 and causing the preform 20 to bulge.

  The hydraulic molding apparatus 100 applied to the hydraulic molding process has a hydraulic pressure supply means and a molding die (see FIGS. 5 and 6).

  The hydraulic pressure supply means includes nozzles 110 and 120 that are inserted into the openings 21 and 22 of the preform 20 and seal the openings 21 and 22. For example, the nozzle 110 is connected to a pressure generator using a pressure-increasing cylinder and a pipe 125 extending from a forming medium source. The pipe 125 is connected to a flow path 115 that extends inside the nozzle 110 and has an opening 116 at the tip of the nozzle 110. The forming medium is introduced into the preform 20 from the opening 116 via the pipe 125 and the flow path 115. The forming medium is, for example, water.

  The mold includes an upper mold 130, a lower mold 135, side molds 140 and 145, and auxiliary molds 150, 155, 160 and 165. The upper mold 130 and the lower mold 135 are disposed so as to be close to and away from each other, and have cavities corresponding to the side wall surfaces 42 and 43 of the vehicle body structural member 40. The side molds 140 and 145 are arranged so as to be close to and away from each other, and have cavities corresponding to the side wall surfaces 44 and 45 of the vehicle body structural member 40. The upper mold 130, the lower mold 135, and the lateral molds 140 and 145 constitute a cavity corresponding to the side wall 41 of the vehicle body structural member 40 as a whole.

  The auxiliary molds 150 and 155 have semicircular concave portions taking into consideration the thickness of the preformed body 20 and the outer peripheral shape of the nozzle 110, are arranged so as to be close to and away from each other, and the preformed body 20 into which the nozzle 110 is inserted. The opening 21 is pressed from above and below to ensure the sealing between the nozzle 110 and the opening 21. The auxiliary molds 160 and 165 have semicircular concave portions in consideration of the thickness of the preformed body 20 and the outer peripheral shape of the nozzle 120, are arranged so as to be close to and away from each other, and the preformed body 20 into which the nozzle 120 is inserted. It is used to press the opening 22 from above and below to ensure sealing between the nozzle 120 and the opening 22.

  With reference to FIG. 7, the hydraulic forming process will be described in detail.

  The preform 20 is placed on the lower mold 135. At this time, the end surfaces 13 and 14 to which the plate material 10 is bonded are positioned so as to face the lower mold 135, and the portion to which the wire 17 is bonded is positioned to face the upper mold 130.

  The nozzles 110 and 120 are inserted into the openings 21 and 22 at both ends of the preform 20.

  When the auxiliary molds 150 and 155 are close to each other, the opening 21 of the preform 20 is pressed from above and below to closely contact the inner surface of the opening 21 and the outer periphery of the nozzle 110. Similarly, the auxiliary molds 160 and 165 closely contact the inner surface of the opening 22 and the outer periphery of the nozzle 120. Thereby, the confidentiality of the preform 20 is ensured.

  At this time, since the openings 21 and 22 of the preform 20 are forcibly deformed, the roundness of the preform 20 in the bending process is not required to be high.

  Thereafter, the molding medium is introduced into the preform 20 from the opening 116 at the tip of the nozzle 110 via the pipe 125 and the flow path 115, and a hydraulic pressure is applied to the preform 20.

  The internal hydraulic pressure of the preform 20 rises and the preform 20 starts to bulge, and the side molds 140 and 145 come close to press the preform 20 from the side. Subsequently, the upper die 130 and the lower die 135 are close to each other and press the preform 20 from the up and down direction. The internal hydraulic pressure of the preform 20 is controlled so as not to buckle by the pressing by the upper mold 130, the lower mold 135, and the side molds 140 and 145.

  When the inside of the preform 20 reaches a predetermined final hydraulic pressure, the supply of the forming medium is stopped and held for a predetermined time. Then, after releasing the pressure, the mold is opened, and the hydroformed product 30 is taken out. Since the end of the hydroformed product 30 is substantially cylindrical, the vehicle body structural member 40 is obtained by trimming.

  As described above, the manufacturing method according to the present embodiment can manufacture a vehicle body structural member having a wire joined to a cylindrical side wall.

  It should be noted that the wire rod to be joined to the preform is arranged on the inner side so that the upper mold, the lower mold and the side mold cavity are not damaged, and the conventional mold is diverted. Since the increase in cost can be suppressed and the same external shape as that of the conventional vehicle body structural member can be obtained, it is not necessary to change the design of other parts to be fastened, and the external appearance is also favorable, which is preferable.

  However, it is also possible to arrange the wire on the outside of the preform as necessary. In this case, the upper mold, the lower mold, and the side mold may be made of a material that is not easily damaged by the wire, or a recess corresponding to the shape of the wire may be formed in a cavity portion that directly contacts the wire. preferable. The recess can be formed by cutting, for example.

  FIG. 9 is a perspective view for explaining the bending test, FIG. 10 is a chart for explaining the preparation conditions of the test bodies S1 to S8 applied to the bending test, FIG. 11, FIG. 12, FIG. 13 and FIG. These are the perspective views for demonstrating test body S2, test body S3, test body S4, and test body S5 which concern on an Example.

  In the bending test, the specimen S (S1 to S8) was placed on the cradle 200, 210, the reaction force when the striker 220 was dropped was measured, and the energy absorption amount at a displacement of 50 mm was evaluated. The length of the test body S in the axial direction is 900 mm, and the cross section perpendicular to the axial direction has a rectangular shape of 50 mm × 50 mm. The fulcrum interval of the cradle 200, 210 with respect to the test body S is 700 mm. The width of the striker 220 in the axial direction of the test body S is 70 mm, the weight is 500 kg, and the dropping speed is 7.67 m / sec.

  In the test bodies S1 to S5 according to the examples, the side wall material is common, and the number of wires and the arrangement position are changed. The side wall material is a 1 mm thick steel plate having a tensile strength of about 590 MPa, and the wire is made of a material mainly composed of iron, has a diameter of 3 mm, and has a tensile strength of about 1.5 GPa.

  The test body S1 corresponds to the vehicle body structural member 40, and as shown in FIG. 1, three wire rods 47 are joined to the inner surface of the side wall surface 42, which is the load input surface, with respect to the load input direction. In addition, three wire rods 48 and 49 are respectively joined to the inner surfaces of the side wall surfaces 44 and 45, which are substantially parallel surfaces, and the weight thereof is 1.47 kg.

  The test body S2 corresponds to the vehicle body structural member 40A shown in FIG. 11, and the three wire rods 47 are joined only to the inner surface of the side wall surface 42, and its weight is 1.46 kg. The test body S3 corresponds to the vehicle body structural member 40B shown in FIG. 12, and three wire rods 48 and 49 are joined only to the inner surfaces of the side wall surfaces 44 and 45, respectively, and the weight is 1.43 kg. is there.

  The test body S4 corresponds to the vehicle body structural member 40C shown in FIG. 13, and two wire rods 47 are joined to the inner surface of the side wall surface 42, and three wire rods 48 are bonded to the inner surfaces of the side wall surfaces 44 and 45. , 49 are joined, and their weight is 1.46 kg. The test body S5 corresponds to the vehicle body structural member 40D shown in FIG. 14, and one wire 47 is joined to the inner surface of the side wall surface 42, and three wires 48 are attached to the inner surfaces of the side wall surfaces 44 and 45. , 49 are joined, and their weight is 1.44 kg.

  The test body S6 is related to the comparative example, and is the same as the test bodies S1 to S5 except that the wire is not joined, and its weight is 1.42 kg. The test bodies S7 and S8 are related to the comparative example, and are different from the test body S6 in terms of plate thickness and weight. The plate thickness and weight of the specimen S7 are 1.2 mm and 1.70 kg, and the plate thickness and weight of the specimen S8 are 1.4 mm and 1.98 kg.

  FIG. 15 is a chart for explaining the test results of the bending test, and FIG. 16 is a graph for explaining the differences between the test bodies S1 to S5 according to the example and the test bodies S6 to S8 according to the comparative example. . The vertical axis and horizontal axis of the graph of FIG. 16 indicate the energy absorption [J] and weight [kg] of the test bodies S1 to S8.

  The energy absorption amounts of the test bodies S1 to S5 are 365J to 491J. On the other hand, the energy absorption amount of the specimen S6 according to the comparative example having the same plate thickness is 305J. Therefore, it was confirmed that the amount of absorbed energy, that is, the strength of the test bodies S1 to S5 was improved based on the joining of the wires. Note that the specimens S6 to S8 have an energy absorption amount of 305J to 480J corresponding to an increase in plate thickness (weight).

  Moreover, the energy absorption amount of the test body S1 and the test body S4 is 491J and 489J. Compared with the test body S1 and the test body S4, the energy absorption amount of the test body S6 having substantially the same weight is 305J. Therefore, the amount of absorbed energy is improved 1.6 times.

  Compared with the test body S1 and the test body S4, the weight of the test body S8 having substantially the same amount of absorbed energy is 1.98 kg. Since the weights of the test body S1 and the test body S4 are 1.47 kg and 1.46 kg, the weight can be reduced by 25% or more.

  As described above, the present embodiment can provide a light-weight vehicle body structural member having good strength and formability and a method for manufacturing the same.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims.

  For example, the vehicle body structural member may have a cross-sectional shape other than a rectangle. Further, when a plurality of wire rods are arranged on the same surface, they can be arranged so as to intersect with each other or arranged apart from each other in the axial direction.

It is a perspective view for demonstrating the vehicle body structural member which concerns on embodiment of this invention. It is sectional drawing for demonstrating the vehicle body structural member which concerns on embodiment of this invention. It is a perspective view for demonstrating the manufacturing method of the vehicle body structural member shown by FIG. 3, and has shown the joining process. FIG. 4 is a perspective view for explaining a bending process following FIG. 3. It is sectional drawing for demonstrating the hydraulic forming apparatus which concerns on embodiment of this invention. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. FIG. 5 is a cross-sectional view for explaining a hydraulic forming process following FIG. 4. It is a perspective view for demonstrating the hydraulic molding product produced from a hydraulic molding process. It is a perspective view for demonstrating a bending test. It is a chart for demonstrating the creation conditions of the test bodies S1-S8 applied to the bending test. It is a perspective view for demonstrating test body S2 which concerns on an Example. It is a perspective view for demonstrating test body S3 which concerns on an Example. It is a perspective view for demonstrating test body S4 which concerns on an Example. It is a perspective view for demonstrating test body S5 which concerns on an Example. It is a chart for demonstrating the test result of a bending test. It is a graph for demonstrating the difference with test body S1-S5 which concerns on an Example, and test body S6-S8 which concerns on a comparative example.

Explanation of symbols

10. Plate material,
11 ..
12. The outer surface,
13, 14, ... end face,
17-19 ... Wires,
20. Pre-formed body,
21, 22 ··· opening,
30 ・ ・ Hydraulic molded products,
40, 40A, 40B, 40C, 40D .. body structure member,
41 .. Side wall,
42 to 45 .. side wall surface,
47, 48, 49 ... Wire
100 ・ ・ Hydraulic molding equipment,
110, 120 .. nozzle
115..
116 .. opening,
125 ... Piping
130 ... upper mold,
135 ... lower mold,
140,145 ... side type,
150, 155, 160, 165 .. auxiliary type,
200,210 .. cradle,
220 ... striker,
S, S1 to S5 .. Specimen (Example),
S6 to S8 .. test body (comparative example),
X ... Axial direction,
Y ... Cross direction.

Claims (8)

A vehicle body structural member on which a bending load acts,
A cylindrical side wall, and
A vehicle body structural member having a wire joined to the side wall.   The vehicle body structure member according to claim 1, wherein the wire is disposed on an inner surface of the cylindrical side wall.   The vehicle body structure member according to claim 1, wherein the wire is disposed on a load input surface of the cylindrical side wall.   The vehicle body structure member according to claim 1, wherein the wire is disposed on a surface substantially parallel to an input direction of a load on the cylindrical side wall.   The vehicle body structure member according to claim 1, wherein the wire is disposed on a load input surface and a surface substantially parallel to a load input direction on the cylindrical side wall. .   The vehicle body structural member according to claim 1, wherein welding is applied to the joining. A method of manufacturing a tubular vehicle body structure member on which a bending load acts,
A joining process for joining a wire to a flat material,
A bending process for forming a hollow preform by applying bending to the material to which the wire is bonded and bonding the end faces; and
A hydraulic forming step for forming a cylindrical hydraulic molded product corresponding to the vehicle body structural member by applying a hydraulic pressure to the interior of the preform and causing the preform to bulge;
The said wire is positioned in the said joining process so that it may be arrange | positioned at the cylindrical side wall of the said hydraulic pressure molded product. The manufacturing method characterized by the above-mentioned.   The manufacturing method according to claim 7, wherein in the bending process, bending is performed so that a surface of the material to which the wire is bonded faces inward.

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