Reinforcement unit and reinforcement member

Abstract

The present invention provides a reinforcing unit to be attached to a body frame, the reinforcing unit comprising a beam member 18 and one or more reinforcing members 20A, 20B to be attached to the beam member 18, wherein: the beam member 18 has an inner surface part 22 provided on a frame side where the body frame exists, an outer surface part 24 provided on a counter frame side, that is, the opposite side of the body frame, and side surface parts 26A, 26B that connect the inner surface part 22 and the outer surface part 24; and the reinforcing members 20A, 20B suppress a bulge deformation of the side surface parts 26A, 26B when impact load is input to the outer surface part 24.

Description

Technical Field

[0001] This disclosure relates to a reinforcement unit.

Background Art

[0002] In structures such as vehicles, a reinforcement unit such as a bumper beam may be incorporated to reduce the impact generated during a collision with an external object. The reinforcement unit usually includes a beam material attached to a main body frame such as a vehicle body frame.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In addition to the beam material, the reinforcement unit may include a reinforcement member for reinforcing the beam material in order to enhance the impact absorption performance (see, for example, Patent Document 1). The inventor of the present application has found a new idea for obtaining good impact absorption performance in such a reinforcement unit.

[0005] One object of this disclosure is to provide a technique capable of obtaining good impact absorption performance in a reinforcement unit.

Means for Solving the Problems

[0006] The reinforcing unit of this disclosure is a reinforcing unit attached to a main frame, comprising a beam material and at least one reinforcing member attached to the beam material, wherein the beam material comprises an inner surface portion provided on the frame side of the main frame, an outer surface portion provided on the opposite side of the frame, and a side portion connecting the inner surface portion and the outer surface portion, and the reinforcing member suppresses bulging deformation of the side portion when an impact load is applied to the outer surface portion.

[0007] The reinforcing member of this disclosure is a reinforcing member attached to a main frame, wherein the beam material comprises an inner surface portion provided on the frame side of the main frame, an outer surface portion provided on the opposite side of the frame, and a side portion connecting the inner surface portion and the outer surface portion, and the reinforcing member suppresses bulging deformation of the side portion when an impact load is applied to the outer surface portion. [Effects of the Invention]

[0008] According to this disclosure, good shock absorption performance can be obtained in the reinforcement unit. [Brief explanation of the drawing]

[0009] [Figure 1] This is a top view of the reinforcement unit of the embodiment. [Figure 2] This is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] This figure schematically shows a portion of the III-III end face of Figure 1. [Figure 4A] This is a schematic end view showing a reinforcing member of a reference configuration. [Figure 4B] This diagram schematically shows the deformation state of the reinforcing member in the reference configuration. [Figure 4C] This is another diagram schematically showing the intermediate deformation state of the reinforcing member in the reference configuration. [Figure 5A] This is a schematic end view showing the reinforcing member of the embodiment. [Figure 5B] This is the first explanatory diagram, which schematically shows the deformation state of the reinforcing member of the embodiment. [Figure 5C] This is a second explanatory diagram schematically showing the deformation state of the reinforcing member of the embodiment. [Figure 5D] This is a third explanatory diagram schematically showing the deformation state of the reinforcing member of the embodiment. [Figure 6] This is a schematic diagram showing the computational model that serves as a prerequisite for FEM analysis. [Figure 7] This graph shows the relationship between reaction force and stroke amount obtained from FEM analysis. [Figure 8] This is a configuration diagram showing a molding apparatus according to an embodiment. [Figure 9A] This is the first explanatory diagram schematically showing the molding method of the embodiment. [Figure 9B] This is a second explanatory diagram schematically showing the molding method of the embodiment. [Figure 9C] This is a third explanatory diagram schematically showing the molding method of the embodiment. [Modes for carrying out the invention]

[0010] The embodiments are described below. The same reference numerals are used for identical components, and redundant explanations are omitted. For the sake of clarity, components are omitted, enlarged, or reduced in each drawing. The drawings should be viewed in accordance with the orientation of the reference numerals.

[0011] Refer to Figures 1 and 2. The reinforcement unit 10 is attached to the main frame 12, which is part of the structure. The main frame 12 supports other parts of the structure. In this embodiment, the structure is a vehicle such as an automobile, and the main frame 12 is a vehicle frame that supports other parts of the vehicle. The specific example of the structure is not particularly limited and may be a crane, for example. The reinforcement unit 10 in this embodiment is a bumper beam used in the front bumper of a vehicle. The main frame 12 in this embodiment includes a pair of left and right side members 14 and a cross member (not shown) that connects the pair of side members 14. The reinforcement unit 10 is attached to the main frame 12 via a crush can 16.

[0012] Hereinafter, regarding the positional relationship of the reinforcement unit 10, explanations will be given using the longitudinal direction X, the lateral direction Y, and the vertical direction Z that are perpendicular to each other. When the reinforcement unit 10 is used in a vehicle, these directions X, Y, and Z correspond to the longitudinal direction, the lateral direction, and the vertical direction of the vehicle. In this case, the longitudinal direction X and the lateral direction Y are horizontal directions perpendicular to each other. The vertical direction Z is the vertical direction. One of the longitudinal direction X and the lateral direction Y is taken as the first specific direction A, and the other is taken as the second specific direction B. The vertical direction Z is taken as the third specific direction. The reinforcement unit 10 is disposed outside the body frame 12 in the first specific direction A. The first specific direction A in this embodiment is the longitudinal direction X. The outside of the first specific direction A refers to the side away from the body frame 12 in the first specific direction A (the front side in this embodiment). Hereinafter, the side where the body frame 12 is located with respect to the reinforcement unit 10 in the first specific direction A is referred to as the frame side Sa (the rear side in this embodiment). Also, the side opposite to the body frame 12 in the first specific direction A is referred to as the anti-frame side Sb (the front side in this embodiment). The second specific direction B is the direction in which the beam member 18 described later extends as a whole, and the first specific direction A is the direction that approaches or moves away from the body frame 12 perpendicular to the second specific direction B, and it can also be said that the third specific direction (vertical direction Z) is the direction perpendicular to these.

[0013] The reinforcement unit 10 has the role of absorbing the impact generated during a collision with an external object. The reinforcement unit 10 includes a beam member 18 attached to the body frame 12 and at least one reinforcement member 20A, 20B attached to the beam member 18. The reinforcement members 20A, 20B have the role of reinforcing the beam member 18.

[0014] As a whole, the beam member 18 is an elongated body extending in the second specific direction B (the lateral direction Y in this embodiment). As a whole, the beam member 18 exhibits an arc shape protruding toward the anti-frame side Sb. Each of both ends of the beam member 18 is fixed to the body frame 12.

[0015] The cross-section of the beam material 18 perpendicular to the longitudinal direction C is a closed cross-sectional shape, and the overall shape is polygonal. The beam material 18 in this embodiment has a continuous closed cross-sectional shape that is seamlessly continuous around its entire circumference. The beam material 18 can also be said to be composed of a single pipe material. The thickness of the beam material 18 is not particularly limited, but for example, it is 1.0 mm or more and 2.3 mm or less.

[0016] The beam material 18 is made of a metal, such as high-tensile steel or ultra-high-tensile steel. The microstructure of the beam material 18 mainly consists of a hardened structure such as α-martensite, or a tempered structure such as sorbite or troostite. The beam material 18, which has a continuous closed cross-sectional shape with such a microstructure as its main phase, is made from an integrally molded product obtained by hot air blow molding, as described later.

[0017] The beam material 18 comprises an inner surface portion 22 provided on the frame side Sa, an outer surface portion 24 provided on the opposite frame side Sb, a pair of side portions 26A and 26B connecting the inner surface portion 22 and the outer surface portion 24, and flange portions 28 formed on the side portions 26A and 26B.

[0018] The inner surface portion 22, as a whole, has a plate-like shape facing the frame side Sa. The outer surface portion 24, as a whole, has a plate-like shape facing the opposite frame side Sb. The inner surface portion 22 and the outer surface portion 24 face each other in the first specific direction A (front-rear direction X).

[0019] The outer surface 24 functions as a surface that receives the impact load in advance when an external object collides with the reinforcing unit 10 from the opposite side Sb of the frame. The outer surface 24 is provided with a plurality of grooves 30 that extend along the longitudinal direction of the beam material 18. The plurality of grooves 30 contribute to improving the impact absorption performance by improving the cross-sectional performance of the outer surface 24. The plurality of grooves 30 are recessed into the frame side Sa of the outer surface 24. Through holes 32 for passing fastening members such as bolts may be formed in the outer surface 24.

[0020] The pair of side sections 26A and 26B include an upper side section 26A positioned on the upper side and a lower side section 26B positioned on the lower side. The side sections 26A and 26B of this embodiment include a corner section 34 that is convex outward in the vertical direction Z, a frame side section 36 extending from the corner section 34 toward the frame side Sa, and an anti-frame side section 38 extending from the corner section 34 toward the anti-frame side Sb. The corner section 34 of the side sections 26A and 26B has an uneven shape that is undulating in a first specific direction A (front-to-back direction X) as it approaches the longitudinal direction C of the beam material 18 when viewed from the vertical direction Z (see Figure 1).

[0021] The flange portion 28 contributes to improving the impact absorption performance by improving the cross-sectional properties of the beam material 18. The flange portion 28 protrudes outward in the vertical direction Z from the side portions 26A and 26B of the beam material 18. The flange portion 28 is formed by bending a part of the beam material 18 in a folding manner. In this embodiment, the flange portion 28 is formed at the end portion 26a on the side portion 26A and 26B that is not on the frame. The portion 28a of the flange portion 28 that is not on the frame Sb is continuous with the outer surface portion 24 as part of the outer surface portion 24.

[0022] In a beam material 18 obtained by hot air blow forming, the protrusion amount P1 of the flange portion 28 can be set to, for example, 5 mm or less if it is not provided for welding purposes. This means that it is set to a size smaller than the typical protrusion amount of the flange portion 28 required as a spot welding allowance (approximately 15 mm to 20 mm). This spot welding allowance is necessary when obtaining a beam material 18 by welding multiple metal plates. Here, the protrusion amount P1 refers to the dimension in the vertical Z direction of the portion of the flange portion 28 where a part of the beam material 18 is folded.

[0023] In this embodiment, at least one reinforcing member 20A, 20B includes an upper reinforcing member 20A and a lower reinforcing member 20B that is separate from the upper reinforcing member 20A. The configuration of the lower reinforcing member 20B when viewed from below is the same as the configuration of the upper reinforcing member 20A when viewed from above, so it is omitted from the illustration here.

[0024] The upper reinforcing member 20A covers the upper surface portion 26A of the beam material 18 from the outside (upper side) in the vertical direction Z. The upper reinforcing member 20A is provided along the upper surface portion 26A of the beam material 18. It can also be said that the upper reinforcing member 20A is provided so as to extend along the upper surface portion 26A of the beam material 18 in the longitudinal direction C of the beam material 18. The lower reinforcing member 20B covers the lower surface portion 26B of the beam material 18 from the outside (lower side) in the vertical direction Z. The lower reinforcing member 20B is provided along the lower surface portion 26B of the beam material 18. It can also be said that the lower reinforcing member 20B is provided so as to extend along the lower surface portion 26B of the beam material 18 in the longitudinal direction C of the beam material 18. The upper reinforcing member 20A and the lower reinforcing member 20B are arranged with a gap between them in the vertical direction Z. The reinforcing members 20A and 20B are made of integrally molded products such as press-formed metal plates.

[0025] The reinforcing members 20A and 20B partially cover the beam member 18 in a portion of the longitudinal direction C of the beam member 18. The reinforcing members 20A and 20B cover at least the central part 18a in the longitudinal direction of the beam member 18, which is prone to deformation when it collides with an external object. The dimension of the beam member 18 in the left-right direction Y (second specific direction B) is denoted as dimension La. In this embodiment, the reinforcing members 20A and 20B cover the beam member 18 in a range in the second specific direction B that is less than half of dimension La.

[0026] The reinforcing members 20A and 20B do not cover the outer surface 24 of the beam material 18 from the opposite side Sb of the frame. In other words, the reinforcing members 20A and 20B are not positioned to overlap the outer surface 24 of the beam material 18 on the opposite side Sb of the frame.

[0027] The reinforcing members 20A and 20B each include a side plate portion 40 that covers the side portions 26A and 26B of the beam material 18 from the outside in the vertical direction Z, an inner plate portion 42 positioned on the frame side Sa relative to the inner surface portion 22 of the beam material 18, and a receiving portion 44 provided on the outer end portion 40a of the side plate portion 40 on the opposite frame side Sb.

[0028] The side plate portion 40 extends from the frame side Sa to the opposite frame side Sb. The side plate portion 40 covers the side portions 26A and 26B of the beam material 18 from the outside in the vertical direction Z, including the corner portion 34.

[0029] Refer to Figures 1 and 3. The side plate portion 40 is formed such that convex portions 46 and concave portions 48 are arranged alternately in the vertical direction Z toward the left-right direction Y (second specific direction B). The convex portions 46 are convex outward in the vertical direction Z (away from the beam material 18). The concave portions 48 are concave inward in the vertical direction Z (closer to the beam material 18). In this embodiment, three convex portions 46 and two concave portions 48 are arranged alternately. Welding holes 50 are formed in the concave portions 48. The concave portions 48 are in contact with the side portion 38 opposite the frame of the beam material 18, and the convex portions 46 are positioned at a distance from the beam material 18. The side plate portion 40 is fixed to the side portions 26A and 26B of the beam material 18 by welding the inner circumference of the welding holes 50.

[0030] The side plate portion 40 is provided with a dimensional change portion 52 that gradually decreases in the left-right direction Y (second specific direction B) as it approaches the frame side Sa. In this embodiment, the dimensional change portion 52 is provided in a continuous range of the side plate portion 40 from the end of the frame side Sa toward the opposite frame side Sb.

[0031] Let Lma be the maximum dimension of the side plate portion 40 in the left-right direction Y (second specific direction B), and Lmb be the maximum dimension of the inner plate portion 42 in the left-right direction Y (second specific direction B). In this embodiment, the maximum dimension Lmb of the inner plate portion 42 is less than or equal to half the maximum dimension Lma of the side plate portion 40.

[0032] Refer to Figure 2. The inner plate portion 42 is connected to the side plate portion 40 via a bent portion 54, and the side plate portion 40 and the inner plate portion 42 together form an L shape. The inner plate portion 42 covers the edge portion in the vertical direction Z of the inner surface portion 22 of the beam material 18 from the frame side Sa, but does not cover the central portion 22a in the vertical direction Z of the inner surface portion 22 from the frame side Sa. In other words, the inner plate portion 42 is not positioned to overlap with the central portion 22a of the inner surface portion 22 of the beam material 18 in the front-rear direction X (first specific direction A).

[0033] The inner plate portion 42 is continuous with the convex portion 46 located on the central side of the side plate portion 40 in the left-right direction Y (second specific direction B). The inner plate portion 42 is fixed to the inner surface portion 22 of the beam material 18 by line welding the edge portion 42a of the inner plate portion 42.

[0034] The receiving portion 44 is formed by bending the outer end portion 40a of the side plate portion 40 outward in the vertical direction Z. The receiving portion 44 is positioned at a distance from the flange portion 28 of the beam material 18 on the frame side Sa. The receiving portion 44 is positioned to overlap the flange portion 28 in the front-rear direction X (first specific direction A) and has a surface portion 44a that faces the flange portion 28 in the front-rear direction X. As described later, the receiving portion 44 has the role of receiving the flange portion 28 of the beam material 18 when the flange portion 28 of the beam material 18 attempts to displace towards the frame side Sa. Due to this relationship, the receiving portion 44 is provided in the vicinity of the flange portion 28 of the beam material 18. The receiving portion 44 is provided on the side Sb opposite the corner portion 34 of the side portions 26A and 26B of the beam material 18.

[0035] Next, the effects of the reinforcement unit 10 will be explained.

[0036] First, the deformation behavior of the reference-mode reinforcement unit 10 will be explained. Refer to Figures 4A, 4B, and 4C. The reference-mode reinforcement unit 10 has a beam member 18 with the same structure as the embodiment, but does not have reinforcing members 20A and 20B. When an impact load Fa toward the frame side Sa is applied to the outer surface 24 of the beam member 18, the side portions 26A and 26B of the beam member 18 deform by bulging outward in the vertical direction Da (see range S1). At this time, when the beam member 18 has a flange portion 28, bulging deformation of the side portions 26A and 26B is more likely to occur starting from the corner portion 34 of the side portions 26A and 26B compared to when the beam member 18 does not have a flange portion 28. This is a new finding obtained through analytical methods.

[0037] Next, the deformation behavior of the reinforcement unit 10 of the embodiment will be described. Refer to Figures 5A, 5B, 5C, and 5D. Here, the relationship between the upper surface portion 26A of the beam material 18 and the upper reinforcement member 20A is illustrated. The following explanations also apply to the relationship between the lower surface portion 26B of the beam material 18 and the lower reinforcement member 20B.

[0038] As described above, when an impact load Fa is applied to the outer surface 24 of the beam member 18, the side surfaces 26A and 26B of the beam member 18 attempt to deform outward in the vertical direction Da. At this time, the side plates 40 of the reinforcing members 20A and 20B restrain this outward deformation by contacting the side surfaces 26A and 26B of the beam member 18 from the outside (see range S2). In other words, the side plates 40 of the reinforcing members 20A and 20B suppress the outward deformation of the side surfaces 26A and 26B of the beam member 18. This suppresses the premature progression of plastic deformation in a localized area along the longitudinal direction C on the outer surface 24 of the beam member 18, and promotes plastic deformation of the beam member 18 over a wider area along the longitudinal direction C. Consequently, good impact absorption performance can be obtained for the entire reinforcing unit 10.

[0039] Here, as the bulging deformation of the side portions 26A and 26B of the beam member 18 progresses, the flange portion 28 of the beam member 18 is displaced toward the frame side Sa (see Figure 5B). Consequently, the flange portion 28 of the beam member 18 comes into contact with the outer end portion 40a of the side plate portion 40 of the reinforcing members 20A and 20B. In this embodiment, the flange portion 28 of the beam member 18 comes into contact with the receiving portion 44 of the reinforcing members 20A and 20B. In this state, the displacement of the flange portion 28 of the beam member 18 toward the frame side Sa allows the flange portion 28 of the beam member 18 to press down on the outer end portion 40a of the reinforcing members 20A and 20B. As a result, the flange portion 28 of the beam member 18 can restrain any outward movement Db in the vertical direction of the outer end portion 40a of the reinforcing members 20A and 20B (see Figure 5C). Therefore, the reinforcing members 20A and 20B can firmly restrain the bulging deformation of the side portions 26A and 26B of the beam material 18 while their movement at their outer ends 40a is constrained. At this time, the side plate portions 40A of the reinforcing members 20A and 20B bulge outward in the vertical direction Da, following the bulging deformation of the side portions 26A and 26B of the beam material 18 (see Figure 5D).

[0040] This makes it possible to stably obtain the restraining effect of the reinforcing members 20A and 20B on the bulging deformation of the beam material 18 over a long period of time. Consequently, good shock absorption performance can be stably obtained for the entire reinforcing unit 10. This effect can be obtained even without the receiving portions 44 of the reinforcing members 20A and 20B, but it is easier to obtain stably if the receiving portions 44 are present.

[0041] Thus, in the reinforcement unit 10 of this embodiment, the beam material 18 is plastically deformed first, rather than the reinforcing members 20A and 20B. Furthermore, in the reinforcement unit 10 of this embodiment, the bulging deformation of the side portions 26A and 26B of the beam material 18, which occurs due to the preceding plastic deformation of the beam material 18, is restrained by the reinforcing members 20A and 20B, thereby achieving good shock absorption performance for the entire reinforcement unit 10.

[0042] In order to obtain such good shock absorption performance, it is not necessary to pre-deform the reinforcing members 20A and 20B plastically, and it is not necessary to cover the entire outer surface 24 of the beam material 18 from the side Sb opposite the frame. Furthermore, in order to obtain such good shock absorption performance, it is sufficient to cover only localized areas, such as the outside of the side portions 26A and 26B, in a cross section perpendicular to the longitudinal direction C of the beam material 18. Therefore, the area covered by the reinforcing members 20A and 20B on the beam material 18 can be reduced, and the overall weight of the reinforcing unit 10 can be reduced.

[0043] In order to obtain such good shock absorption performance, the central part 22a of the inner surface 22 of the beam material 18 does not need to be covered from the frame side Sa. In this respect as well, the area covered by the reinforcing members 20A and 20B on the beam material 18 can be reduced, and the overall weight of the reinforcing unit 10 can be reduced.

[0044] As mentioned above, bulging deformation at the side portions 26A and 26B of the beam material 18 is more likely to occur starting from the corners 34 of the side portions 26A and 26B if the beam material 18 has flange portions 28. Therefore, if flange portions 28 and corners 34 are provided on the side portions 26A and 26B of the beam material 18, it becomes easier to control the locations where bulging deformation occurs at the side portions 26A and 26B. In turn, there is the advantage of being able to stably obtain the restraining effect of the bulging deformation of the beam material 18 by the reinforcing members 20A and 20B.

[0045] Each reinforcing member 20A and 20B includes a side plate portion 40 that covers the side portions 26A and 26B of the beam member 18, as well as an inner plate portion 42 positioned on the frame side Sa relative to the inner surface portion 22 of the beam member 18. Therefore, when the side plate portions 40 of the reinforcing members 20A and 20B attempt to bend around the front-rear direction X (first specific direction) axis in accordance with the bulging deformation of the side portions 26A and 26B of the beam member 18, the inner plate portion 42 can restrain the bending deformation of the side plate portion 40. This suppresses, for example, the premature progression of deformation of the reinforcing members 20A and 20B. In other words, the deformation of the side plate portions 40 of the reinforcing members 20A and 20B can be suppressed, and the restraining effect of the reinforcing members 20A and 20B on the bulging deformation of the beam member 18 can be stably obtained over a long period of time. Consequently, good shock absorption performance can be stably obtained for the entire reinforcing unit 10.

[0046] At least one reinforcing member 20A, 20B includes an upper reinforcing member 20A and a lower reinforcing member 20B that is separate from the upper reinforcing member 20A. Therefore, by covering the upper side portion 26A and the lower side portion 26B of the beam material 18 with the individual reinforcing members 20A, 20B, the bulging deformation of the individual side portions 26A, 26B can be restrained. Consequently, better shock absorption performance can be obtained for the entire reinforcing unit 10.

[0047] In addition, compared to the case where the upper side portion 26A and lower side portion 26B of the beam material 18 are covered by a common reinforcing material, the area covered by the reinforcing members 20A and 20B on the inner surface portion 22 of the beam material 18 can be narrowed. Consequently, the overall weight of the reinforcing unit 10 can be reduced.

[0048] Next, we will describe the analysis performed to explain the effect of the reinforcement unit 10 of the embodiment. Refer to Figure 6. In this analysis, LS-DYNA was used as the analysis software to perform an FEM analysis that reproduced a three-point bending test. Both ends of the reinforcement unit 10 were supported by rigid bodies 56 with a support distance L1 of 892 mm. A load was applied to the central part of the reinforcement unit 10 from a rigid body 58 under the conditions of a speed of 0.5 mm / sec and a maximum stroke of 100 mm.

[0049] Refer to Figure 7. Figure 7 shows that a larger reaction force (kN) indicates greater shock absorption performance. FEM analysis was performed on the reinforcement unit 10 of the embodiment described above and the reinforcement unit 10 of the reference embodiment. The data for the reinforcement unit 10 of the embodiment is shown in Figure 7 as "with reinforcement member," and the data for the reinforcement unit 10 of the reference embodiment is shown in Figure 7 as "without reinforcement member." As shown in Figure 7, it can be seen that the reaction force (shock absorption performance) changes significantly depending on the presence or absence of the reinforcement members 20A and 20B. This supports the technical significance of the presence or absence of the reinforcement members 20A and 20B in this disclosure.

[0050] Refer to Figure 8. The molding apparatus 100 for forming the beam material 18 described above will now be explained. The molding apparatus 100 comprises a molding die 106 consisting of a pair of lower dies 102 and upper dies 104, an upper die drive mechanism 108 for moving the upper die 104, a pair of pipe holding mechanisms 112 for holding both ends of the raw pipe 110 which will be the material for the beam material 18, a water circulation mechanism 116 for circulating cooling water in a cooling water passage 114 formed inside the molding die 106, and a control device 118 for controlling these.

[0051] The molding die 106 includes a cavity 120 that forms a space for the target shape to be molded when the lower die 102 and upper die 104 are in the mold closing position (see also Figure 9C). The cavity 120 includes a main cavity portion 120a for molding the portion of the beam material 18 other than the flange portion 28, and a sub-cavity portion 120b for molding the flange portion 28 of the beam material 18.

[0052] The upper mold drive mechanism 108 includes a slider 122 for moving the upper mold 104, a main cylinder 124 for pressurizing the slider 122 downward, a pull-back cylinder 126 for pulling the slider 122 upward, a hydraulic pump 128 for supplying pressurized oil to the main cylinder 124, and a servo motor 130 for controlling the hydraulic pump 128.

[0053] The pipe holding mechanism 112 is positioned on both the left and right sides of the molding die 106. The pipe holding mechanism 112 includes a pair of electrodes 132 that grip the end of the raw pipe 110, a nozzle 134 that supplies compressed gas into the inside of the raw pipe 110, an electrode mounting unit 136 that supports each of the pair of electrodes 132 so that they can be driven individually, and a nozzle mounting unit 138 that supports the nozzle 134 so that it can move forward and backward. The nozzle 134 is connected to a gas circuit 140 that supplies and discharges compressed gas.

[0054] Refer to Figures 9A, 9B, and 9C. An overview of the hot air blow molding method using the molding apparatus 100 described above will be explained. The beam material 18 can be obtained by hot air blow molding, in which the raw pipe 110 is blow-molded with compressed gas while heated by the molding apparatus 100. The operation of the molding apparatus 100 described below is performed under the control of the control device 118.

[0055] First, the raw tube 110 is placed between the lower mold 102 and the upper mold 104 of the molding die 106 (see Figure 9A). Next, the pair of electrodes 132 are moved by the electrode mounting unit 136, so that the pair of electrodes 132 grip the raw tube 110. In this state, the raw tube 110 is heated by Joule heating by applying current to the electrodes 132 of the individual pipe holding mechanism 112. At this time, the raw tube 110 is heated to a temperature range above the Ac3 transformation point temperature in order to quench the raw tube 110.

[0056] Next, the nozzle mounting unit 138 is controlled to advance the nozzles 134 so that they are inserted into each end of the raw tube 110. Then, the servo motor 130 of the upper mold drive mechanism 08 is controlled to lower the upper mold 104 until it is positioned at the mold closing position Pa, thereby closing the molding die 106. At this time, before the molding die 106 is completely closed, low-pressure compressed gas is supplied from the nozzles 134 into the raw tube 110 to start blow molding. Figure 9B shows the state just before blow molding is started. Since the raw tube 110 has been softened by Joule heating, it can be easily expanded by the compressed gas. As a result, the raw tube 110 expands in the main cavity 120a and expands to enter the sub-cavity 120b.

[0057] After this, the upper mold 104 is lowered to the mold closing position Pa, completing the mold closing of the molding die 106 (see Figure 9C). As a result, a portion of the raw tube 110 is pressed by the lower mold 102 and the upper mold 104 within the sub-cavity 120b, forming the flange portion 28 of the beam material 18. After this, high-pressure compressed gas is supplied into the raw tube 110 from the nozzle 134. This causes the raw tube 110 to expand so that the portion of the beam material 18 other than the flange portion 28 contacts the main cavity 120a throughout the entire area of ​​the main cavity 120a. As a result, the portion of the beam material 18 other than the flange portion 28 is formed within the main cavity 120a.

[0058] In the blow molding process described above, the molding die 106 is cooled by cooling water circulated by the water circulation mechanism 116. The raw tube 110 is hardened by the cooling of the mold when it comes into contact with the cooled molding die 106.

[0059] After this, the supply of compressed gas is stopped, the gripping state by the pair of electrodes 132 is released, and the upper mold 104 is raised. After this, the formed beam material 18 is removed from the forming apparatus 100.

[0060] Other variations of each component are described.

[0061] The reinforcement unit 10 may be a bumper beam used in a rear bumper positioned on the rear side of the main frame 12. Up to this point, we have described an example in which the reinforcement unit 10 is positioned outside the front-to-back direction X, which is the first specific direction A, relative to the main frame 12. In addition, the first specific direction A may be the left-to-right direction Y. In this case, the reinforcement unit 10 is positioned outside the left-to-right direction Y relative to the main frame 12. This assumes that the reinforcement unit 10 is a bumper beam used in a side bumper.

[0062] In this example, the beam material 18 is described as a molded product obtained by hot air blow molding. Alternatively, the beam material 18 may be obtained by hydroforming. In this case, a beam material 18 exhibiting a continuous closed cross-sectional shape can be obtained. Furthermore, the beam material 18 may be composed of a welded joint obtained by welding the butt joints of multiple metal plates made from pressed parts.

[0063] The flange portion 28 of the beam material 18 is optional. The flange portion 28 of the beam material 18 may be formed in the middle portion of the side portions 26A and 26B of the beam material 18 in a first specific direction A.

[0064] The reinforcing members 20A and 20B only need to cover the side portions 26A and 26B of the beam material 18 from the outside so as to restrain the bulging deformation of those side portions 26A and 26B, and their specific shape is not particularly limited. For example, the reinforcing members 20A and 20B may cover the central portion 22a of the inner surface portion 22 of the beam material 18 from the frame side Sa. Also, the reinforcing members 20A and 20B do not need to have a receiving portion 44. Furthermore, the reinforcing members 20A and 20B may only have a side plate portion 40 and not have an inner plate portion 42.

[0065] The reinforcing unit 10 only needs to have at least one reinforcing member 20A, 20B, and the number is not particularly limited. There may be only one reinforcing member 20A, 20B, or there may be three or more. Also, one reinforcing member 20A, 20B may cover both the upper side portion 26A and the lower side portion 26B of the beam material 18 from the outside.

[0066] The cross-section of the beam material 18 perpendicular to the longitudinal direction C may not be a closed cross-sectional shape, but may be an open cross-sectional shape that opens in either direction. In addition, the beam material 18 may have only one of the pair of side surfaces 26A and 26B, in addition to the inner surface 22 and outer surface 24.

[0067] The embodiments and variations described above are illustrative. The abstract technical ideas derived from them should not be interpreted restrictively to the content of the embodiments and variations. Many design changes are possible, such as changes, additions, and deletions of components, in the embodiments and variations. In the embodiments described above, the content that allows for such design changes is emphasized with the notation "embodiment." However, design changes are also permitted even in content without such notation. The hatching applied to the cross-sections in the drawings does not limit the material to which the hatching is applied.

[0068] Abstracting the above disclosures, we can grasp the technical ideas described in the following items. Note that item 1 below corresponds to the content of the means for solving the problem.

[0069] (Item 2) The reinforcing unit according to Item 1, wherein the reinforcing member does not cover the outer surface from the side opposite the frame, but covers the side surface from the outside in the vertical direction.

[0070] (Item 3) The reinforcing unit according to Item 1 or 2, wherein the beam material has a flange portion formed on the side surface and protruding outward in the vertical direction, and the reinforcing member comprises a side plate portion that covers the side surface from the outside in the vertical direction, and a receiving portion provided at the outer end of the side plate portion on the side opposite to the frame and positioned on the frame side relative to the flange portion.

[0071] (Item 4) The reinforcing unit according to any one of Items 1 to 3, comprising a side plate portion that covers the side portion from the outside in the vertical direction, and an inner plate portion that is positioned on the frame side relative to the inner surface portion.

[0072] (Item 5) The reinforcing member is a reinforcing unit according to any one of Items 1 to 4, wherein the central part of the inner surface in the vertical direction is not covered from the frame side.

[0073] (Item 6) The side portion includes an upper side portion and a lower side portion, and the at least one reinforcing member includes an upper reinforcing member that covers the upper side portion from the outside and a lower reinforcing member that covers the lower side portion from the outside and is separate from the upper reinforcing member. [Industrial applicability]

[0074] This disclosure relates to a reinforcement unit. [Explanation of symbols]

[0075] 10...Reinforcement unit, 12...Main frame, 18...Beam material, 18a...Central section, 20A...Upper reinforcement member, 20B...Lower reinforcement member, 22...Inner surface section, 24...Outer surface section, 26A...Upper side section, 26B...Lower side section, 28...Flange section, 40...Side plate section, 40a...Outer end section, 42...Inner plate section, 44...Support section.

Claims

1. A reinforcing unit that is attached to the main frame, Beam material and, The beam material comprises at least one reinforcing member attached to the outside of the beam material, The beam material has a continuous closed cross-sectional shape comprising an inner surface provided on the frame side where the main frame is located, an outer surface provided on the opposite side of the frame, and a side surface connecting the inner surface and the outer surface. The reinforcing member is provided with a gap between it and the side surface before an impact load is applied to the outer surface, and is not in contact with the side surface. The reinforcing member is a reinforcing unit that, when the impact load is applied to the outer surface, contacts the side surface to restrain the bulging deformation of the side surface.

2. The reinforcing unit according to claim 1, wherein the reinforcing member is provided along the side portion.

3. The reinforcing member covers the side portion from the outside, as described in claim 2.

4. The reinforcing unit according to any one of claims 1 to 3, wherein the beam material is provided with a flange portion formed on the side surface and protruding outward in the vertical direction.

5. The reinforcing unit according to claim 1, wherein the reinforcing member is not positioned to overlap with the outer surface on the side opposite to the frame.

6. A reinforcing member that reinforces a beam material attached to the main frame, The beam material has a continuous closed cross-sectional shape comprising an inner surface provided on the frame side where the main frame is located, an outer surface provided on the opposite side of the frame, and a side surface connecting the inner surface and the outer surface. The reinforcing member is provided with a gap between it and the side surface before an impact load is applied to the outer surface, and is not in contact with the side surface. The reinforcing member is attached to the outside of the beam material and, when the impact load is applied to the outer surface, contacts the side surface to restrain the bulging deformation of the side surface.

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