JP2014233999A - Vehicle body manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reinforce a vehicle body member made of a steel plate such as a vehicle pillar while minimizing an increase in weight.SOLUTION: In a vehicle body manufacturing method, a pillar 25 is manufactured after identifying a stress concentration section 49 where bending stress concentrates when a load is applied to the pillar 25 made of a steel plate. Then, a patch 45 made of CFRP is put on a tensile surface of the stress concentration section 49. Thus, the vehicle body manufacturing method can maximize a reinforcement effect while minimizing an increase in weight by reinforcing only the stress concentration section 49 of the pillar 25 with the light weight CFRP patch 45. In addition, because the CFRP patch 45 has higher resistance against a tensile load than a compressive load, the vehicle body manufacturing method can not only further improve the reinforcement effect by putting or bolting the CFRP patch 45 on the tensile surface of the stress concentration section 49 but also easily adjust an effectiveness level of reinforcement by simply changing the number of layers of carbon fibers of the CFRP patch 45 or a fiber orientation direction thereof.

Description

  The present invention relates to a vehicle body manufacturing method for automobiles in which a steel plate body member is reinforced with a CFRP patch.

  Inside the center pillar of an automobile, which is composed of a steel plate outer member having a hat-shaped cross section and an inner member formed by laminating a flat plate-like CFRP (carbon fiber reinforced resin) plate on a flat steel plate to form a closed cross section. An arrangement in which a reinforcement in which a strip-like CFRP is formed into a waveform is arranged is known from Patent Document 1 below.

  Further, after bonding an uncured CFRP plate to a steel plate and cutting it into a predetermined shape, the CFRP plate is cured by heating in an autoclave, thereby obtaining a steel plate reinforced with a CFRP plate. It is known.

JP 2010-195352 A JP 2009-178997 A

  By the way, what is described in the above-mentioned patent document 1 is that two reinforcing members, a CFRP plate and a corrugated CFRP reinforcement, are arranged in the entire region from the lower end to the upper end of the center pillar. Since the substantial total length of the force when it is extended is large, it may cause an increase in the weight of the vehicle body.

  The present invention has been made in view of the above circumstances, and an object thereof is to effectively reinforce a steel body member such as a pillar of an automobile while minimizing an increase in weight.

  In order to achieve the above object, according to the first aspect of the present invention, a first step of specifying a stress concentration portion where bending stress concentrates when a load is applied to a steel plate body member; A vehicle body manufacturing method is proposed, which includes a second step of manufacturing a member and a third step of attaching or bolting a CFRP patch to the tensile surface of the stress concentration portion.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect, a vehicle body manufacturing method is proposed in which the size of the patch is larger than the size of the stress concentration portion. .

  According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the patch straddles the ridge line of the tensile surface of the stress concentration portion. Is proposed.

  According to the invention described in claim 4, in addition to the configuration of any one of claims 1 to 3, the continuous fibers of the patch are along a direction advantageous for stress relaxation of the stress concentration portion. A vehicle body manufacturing method is proposed, characterized in that the vehicle bodies are aligned.

  According to the invention described in claim 5, in addition to the configuration of any one of claims 1 to 4, the patch is made of continuous fibers and a thermosetting matrix resin, and the thermosetting matrix. An automobile body manufacturing method is proposed in which the amount of resin is an amount that does not deform the stress concentration portion due to shrinkage during thermosetting.

  The B pillar 25, the side sill 13, the door beam 51, and the floor tunnel reinforcing panel 22 of the embodiment correspond to the vehicle body member of the present invention.

  According to the configuration of claim 1, a stress concentration portion where bending stress is concentrated when a load is applied to a steel plate body member is specified, the vehicle body member is manufactured, and a CFRP patch is formed on the tensile surface of the stress concentration portion. Is attached or bolted, so that only the stress concentration portion of the vehicle body member is reinforced with a lightweight CFRP patch, and the maximum reinforcing effect can be obtained while minimizing the increase in weight. In addition, since the CFRP patch is stronger than the compressive load against the tensile load, the reinforcing effect can be further enhanced by sticking or bolting it to the tensile surface of the stress concentration part, and the CFRP patch. The magnitude of the reinforcing effect can be easily adjusted simply by changing the number of carbon fibers laminated and the fiber orientation direction.

  According to the configuration of the second aspect, since the size of the patch is larger than the size of the stress concentration portion, the deformation of the stress concentration portion can be reliably prevented.

  According to the configuration of claim 3, since the patch straddles the ridge line of the tensile surface of the stress concentration portion, it is possible to effectively prevent the ridge line where the stress is easily concentrated from being bent and deformed.

  According to the fourth aspect of the present invention, since the continuous fibers of the patch are aligned in a direction advantageous for stress relaxation at the stress concentration portion, the effect of reinforcing the stress concentration portion by the patch can be effectively exhibited.

  According to the fifth aspect of the present invention, the patch is composed of continuous fibers and a thermosetting matrix resin, and the amount of the thermosetting matrix resin is an amount that does not deform the stress concentration portion due to shrinkage during thermosetting. Even when the shrinkage amount when the heat-curable matrix resin is thermally cured is larger than the shrinkage amount when the stress concentration portion is thermally shrunk, the deformation of the vehicle body member can be prevented.

The perspective view of the vehicle body frame of a motor vehicle. FIG. 2 is an enlarged sectional view taken along line 2-2 in FIG. 1. FIG. 3 is a view taken along line 3-3 in FIG. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. The figure which shows the action state of the load when a vehicle body rolls over.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In this specification, the front-rear direction, the left-right direction (vehicle width direction), and the up-down direction are defined with reference to an occupant seated in the driver's seat.

  As shown in FIG. 1, a vehicle body frame is connected to a pair of left and right front side frames 11, 11 disposed in the front-rear direction at the front of the vehicle body, and to the rear ends of the left and right front side frames 11, 11. A pair of left and right floor sills 13, 13 disposed in the front-rear direction on the outer side in the vehicle width direction of the left and right floor frames 12, 12, and rear ends of the left and right side sills 13, 13. A pair of left and right rear side frames 14, 14 connected and extending rearward are provided.

  A front crosshead 15 formed between the front ends of the left and right front side frames 11 and 11 is connected by a front bulkhead 15 formed in a frame shape, and a first cross member extending in the vehicle width direction between front and rear intermediate portions of the left and right front side frames 11 and 11. 16, the rear portions of the left and right front side frames 11, 11 are connected by a second cross member 17 extending in the vehicle width direction, between the front and rear intermediate portions of the left and right side sills 13, 13, and the left and right floor frames 12, 12 is connected by third cross members 18 and 18 extending in the vehicle width direction, and the rear ends of the left and right side sills 13 and 13 are connected by a fourth cross member 19 extending in the vehicle width direction. The front ends of the frames 14, 14 are connected by a fifth cross member 20 extending in the vehicle width direction. Between the rear end of the arm 14, 14 are connected by the sixth cross member 21 extending in the vehicle width direction. The second cross member 17 is connected to a front portion 22a of a floor tunnel reinforcing panel 22 made of a plate material extending forward from an intermediate portion in the vehicle width direction of the third cross member 18 and to the front portions of the left and right side sills 13 and 13. Brackets 23, 23 made of a pair of left and right plate members.

  A pair of left and right A-pillars (front pillars) lowers 24 and 24 rise from the front ends of the left and right side sills 13 and 13, and a pair of left and right B pillars (center pillars) 25 and 25 rise from the middle in the front-rear direction. Rises, a pair of left and right C pillars (rear pillars) 26, 26 stand from the rear ends of the left and right side sills 13, 13, and a pair of left and right D pillars 27, 27 stand from the rear ends of the left and right rear side frames 14, 14. To do.

  A connecting member 28 projects outward from the front portion of the front side frame 11, and a lower member 29 connected to the connecting member 28 at the front end and extending rearward and upward is connected to the upper end of the A pillar lower 24. An A-pillar upper 30 extends rearward and upward from an intermediate portion in the front-rear direction of the lower member 29. The A-pillar upper 30, the rear portion of the lower member 29, and the upper end of the A-pillar lower 24 are connected by a front quarter panel 31.

  A roof side rail 33 extends rearward from the rear end of the A pillar upper 30, and the left and right A pillar uppers 30, 30 are connected by a dashboard upper 34 extending in the vehicle width direction, and the front of the left and right roof side rails 33, 33 are connected. The first roof arch 35 that extends in the vehicle width direction is connected between the sections, and the middle portion between the left and right roof side rails 33 and 33 and the upper end of the left and right B pillars 25 and 25 extend in the vehicle width direction. The second roof arch 36 is connected, and the rear ends of the left and right roof side rails 33 and 33 and the upper ends of the left and right D pillars 27 and 27 are connected by a third roof arch 37 extending in the vehicle width direction.

  A rear wheel house 38 stands up from the rear side frame 14, and an outer side in the vehicle width direction of the rear wheel house 38 is covered with a rear fender panel 39.

  As shown in FIGS. 2 to 4, the B pillar 25 includes an outer panel 41 in which a steel plate is press-formed into a hat-shaped cross section that curves outwardly in the vehicle width direction, and a hat shape that curves convex inward in the vehicle width direction. An inner panel 42 in which a steel plate is press-formed in a cross section, and a stiffener 43 in which a steel plate is press-formed in a hat-like cross-section that curves outwardly in the vehicle width direction are joined to their joint flanges 41a, 41a, 42a, 42a, 43a, 43a is a hollow member having a closed cross-section in which three sheets 44 are welded together. The stiffener 43 is bent by two ridge lines 43b and 43b extending in the vertical direction, and a CFRP patch 45 is attached to the inner surface in the vehicle width direction (the surface facing the inner panel 42) to be reinforced.

  The patch 45 is made of a rectangular CFRP sheet, and is constituted by embedding a continuous carbon fiber 46 (a sheet formed by aligning continuous carbon fibers in one direction) in a thermosetting matrix resin 47. Is done. The patch 45 is bonded to the inner surface in the vehicle width direction of the stiffener 43 with an adhesive 48 so that the orientation direction of the continuous carbon fiber of the continuous fiber 46 is along the longitudinal direction (vertical direction) of the B pillar 25.

  As shown in FIG. 5, assuming that the vehicle body rolls over and a load as indicated by an arrow F1 is applied to the roof side rail 33, the load acting on the B pillar 25 is analyzed by a computer. It can be seen that the tensile load F2 acts on the outer panel 41 and the stiffener 43 positioned, and the compressive load F3 acts on the inner panel 42 positioned on the inner side in the vehicle width direction.

  In FIG. 3, an ellipse indicated by a chain line indicates the stress concentration portion 49 which is a region where the tensile load F2 acting on the stiffener 43 exceeds a predetermined value, and the vertical width W2 of the patch 45 is the vertical direction of the stress concentration portion 49. Therefore, the patch 45 covers from the position above the upper end of the stress concentration portion 49 to the position below the lower end. The length of the patch 45 in the front-rear direction is set so as to straddle the ridge lines 43 b and 43 b of the stiffener 43.

  In the previous stage of the welding process, the patch 45 is stuck to the stiffener 43 with the thermosetting matrix resin 47 uncured, and the outer panel 41, the inner panel 42, and the stiffener 43 are integrally welded in the subsequent welding process. In the next painting step, the thermosetting matrix resin 47 is heated and cured by heat generated when the vehicle body passes through the drying furnace, and the patch 45 is firmly attached to the stiffener 43. The patch 45 may be bonded or bolted to the stiffener 43 in a state where the thermosetting matrix resin 47 is cured.

  Since the amount of heat shrinkage when the thermosetting matrix resin 47 is cured is larger than the amount of heat shrinkage when the steel plate is cooled after being heated, the amount of the thermosetting matrix resin 47 (for example, the thickness or area of the patch 45). ) Is excessively large, the stiffener 43 may be deformed by heat shrinkage of the thermosetting matrix resin 47. Therefore, the amount of the thermosetting matrix resin 47 of the patch 45 is limited to an amount that does not cause the deformation of the stiffener 43.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  When the vehicle body rolls over, the tensile load F2 acts on the outer panel 41 and the stiffener 43 of the B pillar 25 serving as the tensile surface by the load F1 input to the roof side rail 33, and the compressive load is applied to the inner panel 42 serving as the compression surface. F3 acts. A stress concentration portion 49, which is a region where the tensile load F2 acting on the stiffener 43 exceeds a predetermined value, is specified in advance, and a CFRP patch 45 is attached to the stress concentration portion 49 to reinforce it, thereby providing a B pillar. As a result, the vehicle interior space can be secured during rollover. That is, since the elongation rate when the tensile load is input is smaller in the CFRP patch 45 than in the steel plate stiffener 43, the extension deformation of the stiffener 43 is suppressed by the patch 45 and the strength of the B pillar 25 is increased. It is done.

  In this way, the stress concentration portion 49 where the bending stress is concentrated is specified, and the CFRP patch 45 is adhered to the tensile surface of the stress concentration portion 49. Therefore, not the entire stiffener 43 but only the stress concentration portion 49 is reduced in weight. By reinforcing with the CFRP patch 45, the maximum reinforcing effect can be obtained while minimizing the increase in weight. In addition, since the CFRP patch 45 is stronger than the compressive load against the tensile load, the reinforcing effect can be further enhanced by sticking it to the tensile surface of the stress concentration portion 49. Moreover, the magnitude of the reinforcing effect can be easily adjusted simply by changing the number of laminated continuous fibers 46 of the CFRP patch 45 and the fiber orientation direction.

  Further, the vertical width W2 of the patch 45 exceeds the vertical width W1 of the stress concentration portion 49, and the length of the patch 45 in the front-rear direction is set so as to straddle the ridge lines 43b and 43b of the stiffener 43. The patch 45 can surely cover the stress concentration portion 49 to enhance the reinforcement effect, and the ridge lines 43b and 43b of the stiffener 43 where the stress tends to concentrate can be reinforced to prevent deformation.

  The aggregate of the patch 45 is formed by laminating continuous fibers 46 of carbon fibers, and the continuous fibers 46 extend along a direction (for example, a direction of tensile load) advantageous for relaxing the stress of the stress concentration portion 49. Since they are aligned, the reinforcing effect of the stress concentration portion 49 by the patch 45 can be effectively exhibited.

  The patch 45 having such a structure can be attached to each part of the body frame other than the B pillar 25 described above. Hereinafter, the example is demonstrated based on FIG.

  The side sill 13 is configured in a closed cross-section by connecting a side sill outer 13a located on the outer side in the vehicle width direction and a side sill inner 13b located on the inner side in the vehicle width direction. When a side impact collision load is input to the side sill 13, a strong tensile load acts on the inner surface in the vehicle width direction of the side sill inner 13, particularly the inner surface in the vehicle width direction near the B pillar, so a CFRP patch 45 is attached thereto. By doing so, the strength of the side sill 13 against side collision can be increased.

  The door beam 51 disposed inside the door 50 is a member having a hat-shaped cross section that opens toward the inner side in the vehicle width direction. The door beam 51 is a stress concentration portion of the tensile load when a collision load of a side collision is input. The opening is closed with a CFRP patch 45 to form a closed section. In this case, it is desirable that the patch 45 is bolted to the flange that forms the opening of the door beam 51. Thereby, the tensile load applied to the door beam 51 at the time of a side collision can be supported by the patch 45, and the deformation of the door beam 51 can be suppressed.

  The floor tunnel reinforcement panel 22 is a member having a hat-shaped cross section that opens downward, and the opening of the floor tunnel reinforcement panel 22 where tensile stress is concentrated by a load applied to the vehicle body during traveling is blocked by a CFRP patch 45. And configured in a closed cross section. Also in this case, the patch 45 is bolted to the flange that forms the opening of the floor tunnel reinforcing panel 22. Thereby, the tensile load applied to the opening part of the floor tunnel reinforcement panel 22 at the time of driving | running | working is supported by the patch 45, and vehicle body rigidity can be improved.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, the order of the first step and the second step of the present invention may be reversed, and the stress concentration portion can be specified after manufacturing the vehicle body member. That is, the first step may be performed on the vehicle body member every time the vehicle body member is manufactured. However, when a plurality of vehicle body members having the same specifications are manufactured as in the embodiment, the specific result obtained for one vehicle body member can be applied to other vehicle body members.

  The specification of the stress concentration portion 29 is not limited to computer simulation, and can be performed by experiment.

  In the embodiment, the patch 45 is attached with the adhesive 48, but it may be attached with the adhesive force of the thermosetting matrix resin 47 itself.

  The aggregate of the patch 45 is not limited to the continuous fiber 46 of the embodiment, and may be a woven fabric knitted with continuous fibers. In that case, it is desirable to align the orientation direction of the continuous fibers in one longitudinal and transverse directions with the tensile direction of the stress concentration portion 49. At this time, if the tensile direction is the longitudinal direction, the breakage of the patch 45 is suppressed against the stress in the lateral direction.

  In the embodiment, the patch 45 is attached to the stiffener 43 of the B pillar 25, but the patch 45 may be attached to the outer panel 41.

  The vehicle body member of the present invention is not limited to the B pillar 25, the side sill 13, the door beam 51, or the floor tunnel reinforcing panel 22 of the embodiment.

13 Side sills (body parts)
22 Floor tunnel reinforcement panel (body parts)
25 B pillar (body member)
43a Ridge line 45 Patch 46 Continuous fiber 47 Thermosetting matrix resin 49 Stress concentration part 51 Door beam (vehicle body member)

Claims (5)

A first step of identifying a stress concentration portion (49) where bending stress is concentrated when a load is applied to the steel body member (13, 22, 25, 51);
A second step of manufacturing the vehicle body member (13, 22, 25, 51);
And a third step of attaching or bolting a CFRP patch (45) to the tension surface of the stress concentration portion (49).   The method of manufacturing a vehicle body for an automobile according to claim 1, wherein the size of the patch (45) is larger than the size of the stress concentration portion (49).   The vehicle body manufacturing method according to claim 1 or 2, wherein the patch (45) straddles a ridge line (43b) of a tensile surface of the stress concentration portion (49).   The automobile according to any one of claims 1 to 3, characterized in that the continuous fibers of the patch (45) are aligned along a direction advantageous for stress relaxation of the stress concentration portion (49). Car body manufacturing method.   The patch (45) is composed of continuous fibers (46) and a thermosetting matrix resin (47), and the amount of the thermosetting matrix resin (47) deforms the stress concentration portion (49) by shrinkage during thermosetting. The method of manufacturing a vehicle body for an automobile according to any one of claims 1 to 4, wherein the amount is not allowed to occur.

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