JP2013189173A - Structural member for automobile body, and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a B pillar having a high peak load per unit mass with respect to a three-point bending load.SOLUTION: A first press-formed body 11 has a hat-like sectional shape formed by including a first vertical wall part 11a, a first ridge line part 11b, a bottom part 11c, a second ridge line part 11d, and a second vertical wall part 11e. A second press-formed body 21 has a groove sectional shape formed by including a first vertical wall part 21a, a first ridge line part 21b, a bottom part 21c, a second ridge line part 21d, and a second vertical wall part 21e. The first vertical wall part 21a adheres to the first vertical wall part 11a, the first ridge line part 21b adheres to the first ridge line part 11b, the bottom part 21c adheres to at least a part of the bottom part 11c, the second ridge line part 21d adheres to the second ridge line part 11d, and the second vertical wall part 21e adheres to the second ridge line part 11e. The sectional peripheral length of the first vertical wall part 21a or the sectional peripheral length of the second vertical wall part 21e is 30 to 80% of the sectional peripheral length of the first vertical wall part 11a or the sectional peripheral length of the second vertical wall part 11e.

Description

  The present invention relates to a structural member for an automobile body and a manufacturing method thereof.

FIG. 16 is an explanatory diagram schematically showing the automobile body 1.
As is well known, almost all automobile bodies 1 are constituted by a monocoque body (unit construction body) in order to achieve both light weight and high rigidity. The monocoque body is usually configured by joining a large number of molded members, usually press-formed from steel plates having a thickness of 2.0 mm or less, in combination with a predetermined shape, for example, by spot welding. Examples of such many structural members (hereinafter referred to as “vehicle body structural members”) include, for example, a B pillar 2, a side sill 3, a roof rail side 4, a bumper reinforcement 5, a door beam (not shown), or a belt line. 6, which are composed of a single molded body or several molded bodies, for example, a press molded body or a roll molded body, to ensure the required vehicle body rigidity. It is comprised as a structural member for automobile bodies.

Here, the “molded body” refers to a member having a ridge line formed by molding a plate-shaped material by an appropriate molding means such as press molding or roll molding.
FIG. 17 is an explanatory view showing an example of a molded body 7 obtained by press-molding a plate-like blank into a cross-sectional hat shape. In particular, FIG. 17 is an explanatory view schematically showing the structure of a front side member that is an example of a structural member 9 for an automobile body configured by combining a molded body 7 and a planar closing plate 8.

As shown in FIG. 17, the molded body 7 has a ridge line portion 7 c that connects one surface 7 a and the other surface 7 b, whereby the rigidity of the structural member 9 for an automobile body is increased.
In recent years, in order to achieve a high level of performance improvement and weight reduction of such a structural member for an automobile body, a steel plate having a different thickness or strength is used as a reinforcing member, and is partially joined to a portion requiring reinforcement in a formed body. Things are starting to happen.

  For example, Non-Patent Document 1 discloses the results of a case study on dynamic bending collapse characteristics of a single-hat bending structure having various reinforcing structures, and Patent Document 1 discloses a center pillar outer panel and a steel plate for thickening. An invention is disclosed in which surface bonding is performed using brazing material.

  Further, Non-Patent Document 2 describes that a patch blank is spot welded to a B-pillar blank, and the blank is hot stamped to realize a strong structure without a gap between components, contributing to weight reduction. Has been.

  According to these conventional techniques, it is possible to improve various performances of the structural member for automobile body while suppressing the increase in the weight of various structural members for automobile body.

JP 2011-88484 A

Japan Society for Automotive Engineers Structural Strength Division Committee Collision Division Committee Collision Analysis Working Group Technical Report Series 36 Latest Structural Research to Improve Member Bending Strength Eurocarbody conference 2007 proceedings

  However, in the above-described conventional technology, an increase in the weight of the molded body is unavoidable by the weight of the reinforcing member to be joined, and there is room for improvement in terms of weight efficiency. In other words, there is a condition for improving the performance of a structural member for an automobile body, in which the reinforcing member is partially attached, with respect to the position and range of the reinforcing member to be used and the dimensions, etc., while suppressing the increase in weight as much as possible. However, there have been no research reports that have clarified this. For this reason, the actual situation is that the arrangement position, range, and dimensions of the reinforcing member must be designed with a safety factor in mind.

  Therefore, the present inventors are required to have a high impact energy absorption capacity and a high load resistance against a three-point bending load such as a B pillar, a side sill, a roof rail side, a bumper reinforcement, a door beam, or a belt line. Regarding structural members for vehicle bodies, the reinforcing members are closely adhered to the bottom, ridgeline, vertical wall and partially in the longitudinal direction in the cross-sectional direction of the molded panel (for example, B-pillar outer panel in the case of B-pillar). Then, a three-point bending test was performed.

  As a result, although the load bearing capacity is certainly increased by providing the reinforcing member, the load bearing capacity per unit weight is hardly increased unexpectedly. Depending on the range in which the reinforcing member is provided, the load bearing capacity per unit weight is rather lowered. It turns out that sometimes.

  The present invention has been made in view of this problem of the prior art, and is a metal plate molded body having a hat-shaped cross-sectional shape, and a metal plate molded body. And a second molded body having a joint with the first molded body, and has a high peak load per unit mass with respect to a three-point bending load and is excellent in load bearing performance per unit weight. It aims at providing a structural member and its manufacturing method.

As a result of intensive studies in order to solve the above problems, the present inventors have obtained knowledge A to E listed below and completed the present invention.
(A) The structural member for an automobile body in which the reinforcing member is partially joined only to the entire surface of the ridge line portion of the molded body forming the main body increases the rigidity of the ridge line portion that mainly bears the three-point bending load. However, since the rigidity of the vertical wall portion of the panel constituting the main body is not improved at all, buckling occurs at an early stage starting from the vertical wall portion, so the load resistance per unit weight does not increase.

  (B) The reinforcing member is a cross-sectional groove-shaped molded body having a ridge line portion and a vertical wall portion continuous therewith, and the reinforcing member is closely adhered from the ridge line portion of the molded body forming the main body to a part of the vertical wall portion. The structural member for an automobile body that has been joined together is a portion corresponding to the edge of the reinforcing member in the vertical wall portion of the molded body forming the main body, and the rigidity of the vertical wall portion changes greatly and discontinuously. As a starting point, the vertical wall portion of the molded body forming the main body may also buckle early.

  (C) The early buckling of the vertical wall portion of the molded body forming the main body has a specific range of the cross-sectional peripheral length of the vertical wall portion of the reinforcing member relative to the cross-sectional peripheral length of the vertical wall portion of the molded body forming the main body. It is solved by setting to.

(D) The effect described in the above item C is particularly prominent when the ratio between the thickness of the molded body forming the main body and the thickness of the molded body forming the reinforcing member is within a specific range.
(E) The effect described in the above section C is that the cross-sectional circumferential length of the vertical wall portion of the molded body forming the reinforcing member and the cross-sectional circumferential length of the vertical wall portion of the molded body forming the main body are in a specific range. This is particularly noticeable.

The present invention is as follows.
(1) For a long automobile body comprising a first molded body that is a molded body of a metal plate and a second molded body that is a molded body of the metal plate and has a joint portion with the first molded body. A structural member,
The first molded body includes at least a first vertical wall portion, a first ridge line portion continuous with the first vertical wall portion, a bottom portion continuous with the first ridge line portion, and a second continuous with the bottom portion. Having a hat-shaped cross-sectional shape by having a second ridge line part and a second vertical wall part continuous to the second ridge line part,
The second molded body includes a first vertical wall portion, a first ridge line portion continuous with the first vertical wall portion, a bottom portion continuous with the first ridge line portion, and a second ridge line continuous with the bottom portion. Having a groove-shaped cross-sectional shape by having a portion and a second vertical wall portion continuous to the second ridge line portion,
By the joining portion, the first vertical wall portion of the second molded body is in close contact with the first vertical wall portion of the first molded body, and the first ridge line portion of the second molded body is the first molded body. In close contact with the first ridge line portion, the bottom portion of the second molded body is in close contact with at least part of the bottom portion of the first molded body, and the second ridge line portion of the second molded body is the first molded body. And the second vertical wall portion of the second molded body is in close contact with the second ridge line portion of the first molded body, and the first of the second molded body. The cross-sectional peripheral length of the first vertical wall portion in the first molded body and / or the cross-sectional peripheral length of the second vertical wall portion in the second molded body and / or Or it is 30 to 80% of the cross-sectional peripheral length of the 2nd vertical wall part in a 1st molded object, The motor vehicle characterized by the above-mentioned Body structural member.

(2) The second molded body is composed of a first molded body element and a second molded body element,
The first molded body element is in close contact with and bonded to at least a part of the first vertical wall portion of the first molded body, the first ridge line portion of the first molded body, and the bottom portion of the first molded body. And the second molded body element includes at least a part of a second vertical wall portion in the first molded body, a second ridge line portion in the first molded body, and a bottom portion in the first molded body. The structural member for an automobile body described in the item (1), wherein the structural member is closely bonded to the vehicle body.

  (3) The ratio of the thickness (t1) of the first molded body to the thickness (t2) of the second molded body is 0.5 to 1.5, (1) or (2) The structural member for an automobile body described in the item).

  (4) The cross-sectional peripheral length (h1) of the first vertical wall portion and / or the cross-sectional peripheral length (h2) of the second vertical wall portion of the second molded body, and the plate thickness of the first vertical wall portion ( t1) and / or the plate thickness (t2) of the second vertical wall portion has a relationship of 0.2 (t2 / t1) +0.2 <h2 / h1 <0.2 (t2 / t1) +0.4. The structural member for an automobile body described in any one of the items (1) to (3), which is satisfied.

  (5) The second molded body has a length of 80% of the total length of the molded body from the one end portion from a position that is 30% of the total length of the molded body from one end portion in the longitudinal direction of the first molded body. The structural member for an automobile body described in any one of the items (1) to (4), characterized in that the structural member is provided in a range up to a position of%.

(6) The vehicle body structure described in any one of items (1) to (5), wherein the second molded body is provided on an inner surface or an outer surface of the first molded body. Element.
(7) The vehicle body described in any one of items (1) to (6), wherein the joint portion is provided intermittently or continuously in the longitudinal direction of the first molded body. Structural member.

(8) The joint portion is provided in a part or all of the longitudinal direction of the second molded body, and is for an automobile body described in any one of the items (1) to (7) Structural member.
(9) The vehicle body described in any one of items (1) to (8), wherein the joint is a spot weld, a seam weld, a laser weld, or a plasma weld Structural member.

(10) The automobile body structural member described in any one of items (1) to (9), wherein the metal plate is a steel plate.
(11) The automobile body structural member described in any one of items (1) to (10), wherein the first molded body is a B-pillar outer panel.

  (12) A method for manufacturing a structural member for an automobile body described in any one of items (1) to (11) above, wherein the first blank in the first blank which is a material of the first molded body It is a material of the second molded body in close contact with a part of the first vertical wall part, the first ridge line part, the bottom part, the second ridge line part, and a part of the second vertical wall part. A method for producing a structural member for an automobile body, wherein the second blank is joined by welding, and the joined first blank and second blank are subjected to press molding or roll molding.

(13) The manufacturing method of the structural member for an automobile body described in (12), wherein the metal plate is a steel plate.
(14) The structural member for an automobile body described in the item (13), wherein the joined first blank and second blank are press-molded in a state of being heated to a temperature of Ac ₃ points or higher. Manufacturing method.

  (15) A method for manufacturing a structural member for an automobile body described in any one of (1) to (11) above, wherein the first blank which is a material of the first molded body is pressed By producing a first molded body having at least a first vertical wall part, a first ridge line part, a bottom part, a second ridge line part and a second vertical wall part by performing molding or roll molding, By performing press molding or roll molding on the second blank, which is the material of the second molded body, the first vertical wall portion, the first ridge line portion, the bottom portion, the second ridge line portion, and the second vertical wall A method of manufacturing a structural member for an automobile body, comprising: manufacturing a second molded body having a portion; and overlapping and joining the first molded body and the second molded body at a predetermined position.

  (16) The manufacturing method of the structural member for a vehicle body described in any one of the items (12) to (15), wherein the first molded body is a B pillar outer panel.

  According to the present invention, the first molded body having a hat-shaped cross-sectional shape, which is a molded body of a metal plate, and the second molded body of the metal plate, having a joint portion between the first molded body. There is provided a long structural member for an automobile body having a molded body and having a high peak load per unit mass with respect to a three-point bending load.

Fig.1 (a) is explanatory drawing which shows typically an example of the structure of B pillar which is the structural member for motor vehicle bodies which concerns on this invention, FIG.1 (b) is AA in FIG.1 (a). FIG. 1C and FIG. 1D are explanatory views showing modified examples of the cross-sectional shape shown in FIG. FIG. 2A to FIG. 2G are perspective views partially showing the arrangement position of the welded portion in the extending direction of the ridge line portion when the welded portion that is the joint portion is a spot-like spot welded portion. FIG. FIG. 3A to FIG. 3J are explanatory views schematically showing the arrangement position of the welded portion in the extending direction of the first ridge line portion when the welded portion is a linear welded portion. is there. FIG. 4A to FIG. 4D are explanatory views schematically showing a case where the welded portion is a combination of a linear welded portion and a dotted welded portion. FIG. 5A to FIG. 5C are explanatory views schematically showing an example of a welding method in the case where the welded portion is formed at a site where the appearance design (beauty) is required. 6 (a) and 6 (b) are explanatory views schematically showing the state of deformation when the B pillar 10 which is a structural member for an automobile body according to the present invention undergoes three-point bending deformation. . Fig.7 (a)-FIG.7 (e) are explanatory drawings which show typically various cross-sectional shapes of B pillar. Fig.8 (a) is explanatory drawing which shows the condition which welded the 2nd molded object to the outer surface of the 1st molded object of B pillar shown to Fig.7 (a), respectively, and FIG.8 (b) is a figure. It is explanatory drawing which shows the condition which welded the 2nd molded object to the outer surface of the 1st molded object of B pillar shown to 7 (c), respectively, and FIG.8 (c) is B pillar shown to FIG.7 (d). It is explanatory drawing which shows the condition which welded the 2nd molded object to the other ridgeline part while welding the 2nd molded object from the ridgeline part of the outer surface of the 1st molded object to the other ridgeline part. FIG. 9A to FIG. 9D are explanatory views partially and schematically showing a suitable formation position of the welded portion in the B pillar in a cross section. 10A and 10B are explanatory views showing a B-pillar numerical experimental model according to the present invention, in which FIG. 10A is a trihedral view and FIG. 10B is a cross-sectional view. FIG. 11A is an explanatory view showing a situation of a three-point bending test, and FIG. 11B is an explanatory view showing a cross-sectional shape of the B pillar 10 of the present invention example. FIG. 12A is a graph showing the results of bending crush analysis of Invention Examples 1 and 2, Comparative Examples 1 and 2 and the conventional example, and FIG. 12B shows Invention Examples 2 and 3 and Comparative Example. It is a graph which shows the result of 2 bending crush analysis. Fig.13 (a) is explanatory drawing which shows the test condition of one-hat three-point bending, FIG.13 (b) is explanatory drawing which shows the cross-sectional shape of one-hat three-point bending. FIG. 14A is an explanatory view showing the spot hitting positions of Examples 1 to 4 of the present invention, and FIG. 14B is an explanatory view showing the spot hitting position of Example 5 of the present invention. FIG. 15 is a graph showing the relationship between the crushing stroke and the crushing load per unit weight in Comparative Examples 4 and 5. FIG. 16 is an explanatory view schematically showing an automobile body. FIG. 17 is an explanatory view showing an example of a molded body obtained by press-molding a plate-like blank into a cross-sectional hat shape.

The present invention will be described in detail with reference to the accompanying drawings. In the following description, the case where the structural member for an automobile body is a B pillar, the metal plate is a steel plate and the forming method of the formed body is press forming is taken as an example. This is an example of the present invention. The present invention is similarly applied to a side sill, roof rail side, bumper reinforcement, door beam, or belt line, and is also applied to a metal plate other than a steel plate, and further applied to a forming method other than press forming. .
1. FIG. 1A is an explanatory view schematically showing an example of the structure of a B pillar 10 that is a structural member for an automobile body according to the present invention, and FIG. FIG. 2 is a cross-sectional view taken along line AA in FIG.

  As shown in FIGS. 1A and 1B, the B pillar 10 includes a first molded body 11 that is a main body, a second molded body 21 that is a reinforcing member, and a third molded body that is a main body. It is comprised with the molded object 31. FIG.

[First molded body 11]
The 1st molded object 11 which is a main body is a press-formed object of the steel plate which is a raw material, and is a B pillar outer panel. The 1st molded object 11 has the 1st vertical wall part 11a, the 1st ridgeline part 11b, the bottom part 11c, the 2nd ridgeline part 11d, and the 2nd vertical wall part 11e at least. The first ridge line portion 11b is continuous with the first vertical wall portion 11a. The bottom part 11c continues to the first ridge line part 11b. The second ridge line portion 11d is continuous with the bottom portion 11c. Further, the second vertical wall portion 11d is continuous with the second ridge line portion 11d.

  In the example shown in FIG. 1, the first molded body 11 includes a third ridge line portion that continues to the first vertical wall portion 11a, 11f, and a first flange portion 11g that continues to the third ridge line portion 11f. And a fourth ridge line portion 11h continuous with the second vertical wall portion 11e and a second flange portion 11i continuous with the fourth ridge line portion 11h.

Thereby, the 1st molded object 11 has a hat-shaped cross-sectional shape as a whole.
In the present invention, the “bottom portion 11c” means a surface portion located on the outermost side of the vehicle body when mounted on the automobile body, and the “first ridge line portion 11b” and the “second ridge line portion 11d” are bottom portions. 11c means a portion with a small radius of curvature, and the “first vertical wall portion 11a” means a portion that is continuous with the first ridge line portion 11b and is provided in a direction intersecting the bottom portion 11c. “Two vertical wall portions 11e” means a portion that is continuous with the second ridge line portion 11d and that is provided in a direction intersecting the bottom portion 11c.

  For this reason, as shown in FIG. 1B, the “hat-shaped cross-sectional shape” in the present invention includes a third ridge line portion 11f continuous to the first vertical wall portion 11a, and a third ridge line portion 11f. The cross-sectional shape is composed of a first flange portion 11g continuous with the second vertical wall portion 11e, a fourth ridge line portion 11h continuous with the second vertical wall portion 11e, and a second flange portion 11i continuous with the fourth ridge line portion 11h. Although it is included, it is not limited to this, As illustrated in FIG. 1D showing a modification of the cross-sectional shape shown in FIG. 1B, the first vertical wall portion 11a and the third ridge line Between the portion 11f, the fifth ridge line portion 11j and the first surface portion 11k continuous to the fifth ridge line portion 11j and the third ridge line portion 11f, and the second vertical wall portion 11e and the fourth The sixth ridge line part 11l, the sixth ridge line part 11l and the fourth ridge between the ridge line part 11h Sectional shape and a second surface portion 11m of continuous section 11h is also included.

  In the case of the cross-sectional shape shown in FIG. 1 (d), the cross-sectional circumference of the second vertical wall portion in the second molded body 21 in the present invention and the first vertical wall portion in the first molded body 11 are used. The ratio of the cross-sectional peripheral length and / or the cross-sectional peripheral length of the second vertical wall portion in the first molded body is the vertical wall portion of the second molded body 21 and the bottom 11c of the first molded body 11a. Means the ratio of the circumferential length of the cross section with the vertical wall portions 11a, 11e on the side close to.

The inclination angle θ of each of the first vertical wall portion 11a and the second vertical wall portion 11e with respect to the bottom portion 11c is not particularly limited, and is typically about 140 to 90 °.
Moreover, the curvature radius of the 1st-4th ridgeline parts 11b, 11d, 11f, and 11h may be a normal one, for example, about 3-25 mm is illustrated.

  The plate thickness of the first molded body 11 is about 1.0 to 2.3 mm when it is a B pillar outer panel, and about 1.0 to 2.0 mm when it is a side sill outer panel. In the case of a roof rail side outer panel, about 0.8 to 2.0 mm is exemplified. In the case of a bumper reinforcement panel, about 1.0 to 2.3 mm is exemplified, and in the case of a door beam panel. Is about 1.0 to 2.0 mm, and in the case of a beltline reinforcement panel, about 1.0 to 2.0 mm is exemplified.

The material of the first molded body 11 is not particularly limited, and a steel plate made of plain steel may be used. However, a high-tensile steel plate may be used in order to reduce the weight by reducing the plate thickness.
The first molded body 11 is configured as described above.

[Second molded body 21]
The 2nd molded object 21 which is a reinforcement member is a press-formed object of a steel plate.
The 2nd molded object 21 has the 1st vertical wall part 21a, the 1st ridgeline part 21b, the bottom part 21c, the 2nd ridgeline part 21d, and the 2nd vertical wall part 21e. The first vertical wall portion 21a is continuous with the first ridgeline portion 21b, the first ridgeline portion 21b is continuous with the bottom portion 21c, the bottom portion 21c is continuous with the second ridgeline portion 21d, and the second ridgeline The portion 21d is continuous with the second vertical wall portion 21e. Thereby, the 2nd molded object 21 has a cross-sectional shape of a groove type.

  The second molded body 21 has a joint portion 22 with the first molded body 11. In addition, in FIG. 1, the junction part 22 is shown notionally. The first vertical wall portion 21a of the second molded body 21 is in close contact with the first vertical wall portion 11a of the first molded body 11 without a gap, and the first ridge line portion 21b of the second molded body 21 is The first molded body 11 is in close contact with the first ridge line portion 11a without a gap, and the bottom 21c of the second molded body 21 is in close contact with at least a part of the bottom 11c of the first molded body 11 without a gap, The second ridge line portion 21d of the second molded body 21 is in close contact with and joined to the second ridge line portion 11d of the first molded body 11 without any gap, and the second vertical wall of the second molded body 21 The part 21e adheres closely to the second ridge line part 11e of the first molded body 11 without a gap.

  Further, in the present invention, “in close contact” means that corresponding portions of the first molded body 11 and the second molded body 21 are superposed substantially without any gap. For this reason, the present invention includes a case where a minute gap inevitable in manufacturing exists between the first molded body 11 and the second molded body 21.

  Although the 2nd molded object 21 may be comprised by the sheet steel of 1 sheet, as illustrated in FIG.1 (c) which shows the modification of the cross-sectional shape shown in FIG.1 (b), it is 1st shaping | molding. It is preferable that the body element 21-1 and the second formed body element 21-2 are constituted by two steel plates because weight reduction can be promoted while preventing performance degradation. In this case, the first molded body element 21-1 is in close contact with and bonded to at least a part of the first vertical wall portion 11a, the first ridge line portion 11b, and the bottom portion 11c of the first molded body 11. At the same time, the second molded body element 21-2 is in close contact with and bonded to at least a part of the second vertical wall portion 11 e, the second ridge line portion 11 d, and the bottom portion 11 c of the first molded body 11.

  The joint portion 22 between the first molded body 11 and the second molded body 21 may be provided intermittently in the longitudinal direction of the first molded body 11 or may be provided continuously. Good. Further, the joint portion 22 may be provided in a part of the longitudinal direction of the second molded body 21 or may be provided in the whole.

  The joint 22 is exemplified by a spot weld formed by spot welding, a seam weld formed by seam welding, a laser weld formed by laser welding, or a plasma weld formed by plasma welding. However, it may be a joint formed by other joining means (for example, adhesion). As will be described later, a ridgeline portion after a bonding method capable of welding both in a state where a flat reinforcing member is superposed on a part of a flat blank material, and a pressed part with high precision Any joining method that joins at a site other than the above can be applied in the same manner.

  FIG. 2A to FIG. 2G partially show the arrangement position of the welded portion 40 in the extending direction of the ridge line portion 11b in the case where the welded portion 40 that is a joined portion is a spot-like spot welded portion. It is a perspective view shown in FIG. A circle in FIGS. 2A to 2G indicates the weld 40. In the illustrated example, a case where the second molded body 21 is joined to the inner peripheral surface of the first ridge line portion 11b provided in the first molded body 21 shown in FIG. 1 by welding will be described as an example. For convenience, the ridge line portion 11 b is illustrated as the first ridge line portion 11 b of the first molded body 11. The same applies to FIGS. 4 to 7 described later.

FIG. 2A shows a case where the welded portion 40 is arranged on the same cross section in the extending direction of the first ridge line portion 11b, and has an effect of easily controlling the formability and deformation in one direction.
FIG. 2B shows a case where the welded portions 40 are staggered in the extending direction of the first ridge line portion 11b, and the number of positions of the welded portions 40 per unit area can be further increased. Can be improved.

FIG.2 (c) is a case where the welding part 40 is arrange | positioned in the same cross section of the extension direction of the 1st vertical wall part 11a and the bottom part 11c, and the effect which is easy to control the moldability and deformation | transformation to one direction. is there.
FIG. 2D shows a case where the welded portion 40 is disposed on the same cross section in the extending direction of the first vertical wall portion 11a, and has an effect of easily controlling the formability and deformation in one direction.

  FIG.2 (e) is a case where the formation position of the welding part 40 is changed according to the position of the extension direction of the 1st ridgeline part 11b, for example, axial crush performance is requested | required in the ridgeline part 11b. By changing the formation position of the welded portion 40 between the portion 11b-1 and the portion 11b-2 that requires bending deformation performance, both the axial crush performance and bending deformation performance of the first molded body 11 are improved. be able to. As described above, by changing the formation position of the welded portion 40 according to the position in the extending direction of the first ridge line portion 11b, it is possible to flexibly respond to various requests required for the first molded body 11. Can do.

  FIG. 2 (f) shows a case where the welded portion 40 is formed by changing the hitting pitch in the extending direction of the first ridge line portion 11b, and the first portion is the same as the case shown in FIG. 2 (c). It is possible to flexibly respond to various requirements required for the molded body 11.

  Further, FIG. 2 (g) shows a case where the welded portion 40 is staggered in the extending direction of the first vertical wall portion 11a, and the striking point below (the edge side) of the vertical wall portion 11a is the staggered arrangement. The first molded body 11 and the entire second molded body 21 are prevented from slipping and deteriorating in performance, and the hitting point above the vertical wall portion 11a (vertical wall center) has the same function as that below. Since the striking point position becomes a bending deformation portion of the vertical wall portion 11a, the strength of the portion is directly improved, and higher performance can be obtained.

FIG. 3A to FIG. 3J schematically show the arrangement position of the welded portion 41 in the extending direction of the first ridge line portion 11 b when the welded portion is a linear welded portion 41. It is explanatory drawing.
Fig.3 (a) shows the case where the welding part 41 is continuously formed linearly in the extension direction of the 1st ridgeline part 11b.

FIG. 3B shows a case where the welded portion 41 is intermittently formed in the extending direction of the first ridge line portion 11b and formed in a linear shape.
FIG.3 (c) shows the case where the welding part 41 is continuously formed in the extending direction of the 1st ridgeline part 11b, and changed the position in the middle, and was formed in linear form.

FIG.3 (d) shows the case where the welding part 41 is formed in the curve shape continuously in the extension direction of the 1st ridgeline part 11b.
FIG.3 (e) shows the case where the welding part 41 is continuously spaced apart in C shape in the extension direction of the 1st ridgeline part 11b.

FIG. 3 (f) shows a case where the welded portion 41 is formed by crossing a part continuously in a C shape in the extending direction of the first ridge line portion 11 b.
FIG. 3G shows a case where the stitch-shaped welds 41 in the cross-sectional direction are formed continuously spaced in the extending direction of the first ridge line part 11b.

FIG. 3 (h) shows a case where the continuous welds 41 in the cross-sectional direction are formed continuously spaced in the extending direction of the first ridge line part 11b.
FIG. 3I shows a case where the welded portion 41 is continuously formed in a straight line shape in the extending direction of the first vertical wall portion 11a.

Further, FIG. 3A shows a case where the welded portion 41 is formed in a straight line continuously in the extending direction of the first vertical wall portion 11a and the bottom portion 11c.
FIG. 4A to FIG. 4D are explanatory views schematically showing a case where the welded portion is a combination of a linear welded portion and a dotted welded portion. The spot-like welded portion may be formed by spot welding or may be formed by laser welding. Further, the linear welded portion may be formed by laser welding or may be formed by seam welding.

  FIG. 4A shows a case where a spot-like welded portion 40 and a linear welded portion 41 are used in combination, and FIG. 4B shows a linear welder having a direction different from that of the linear welded portion 41. 4 (c) shows a case where a C-shaped welded part 41 and a spot-like welded part 40 are used together, and FIG. 4 (d) shows a ridge line part. The case where the linear welded part 41 and the dotted welded part 40 to the direction orthogonal to the extending direction are used together is shown.

  Thus, the 2nd molded object 21 may be extended to the one part or all part of the extension direction of the 1st ridgeline part 11b, and 1 is extended to the extension direction of the 1st ridgeline part 11b. It may be divided into two or more.

  The welded portions 40 to 42 for welding the second molded body 21 to the first ridge line portion 11b are the second molded body 21 and the first molded body 11 when the B pillar 10 receives an external force at the time of collision. It has the effect of preventing the occurrence of a gap between the two and improving the bending deformation characteristics. For this reason, although it is most preferable that the welding parts 40-42 are continuously formed in the extending direction of the 1st ridgeline part 11b, for example, like the spot welding, the extending direction of the 1st ridgeline part 11b It may be formed intermittently. When the welded portions 40 to 42 are intermittently formed in the extending direction of the first ridge line portion 11b, they are adjacent so that the second molded body 21 does not peel from the first molded body 11 during deformation. What is necessary is just to set the space | interval of each welding part 40-42 suitably.

  In some cases, the welds 40 to 42 do not need to be linear in the extending direction of the first ridge line portion 11b, for example, a curved shape bent in an S shape, or a staggered short line shape, Or you may exist in the shape of a dot. In short, the welded portions 40 to 42 may be formed so that the second molded body 21 does not peel from the first molded body 11 when the pillar 10 receives an external force at the time of collision.

  As will be described later, since the second molded body 21 covers not only the first ridge line portion 11b of the first molded body 11 but also the first vertical wall portion 11a, welding is performed at the first ridge line portion 11b. In addition to this, the first vertical wall portion is also welded.

5 (a) to 5 (c) are explanatory diagrams schematically showing an example of a welding method in the case where the welded portions 40 to 42 are formed in a portion where design (appearance) in appearance is required. It is.
When one side or part of the assembled B-pillar 10 is required to have a design on the appearance, that is, a beautiful appearance that does not leave any irregularities such as electrode traces due to welding beads or resistance welding, FIG. It is preferable to use the method exemplified in (a) to FIG.

  Reference numeral 70 in FIG. 5A indicates a laser welding machine. FIG. 5A shows a laser without penetrating the weld bead 41 to the surface a which is the outer surface of the first molded body 11 when the first molded body 11 and the second molded body 21 are laser-welded. By performing welding, the surface a can be kept beautiful.

  Reference numerals 71 and 72 in FIG. 5B denote seam welding electrodes. As shown in FIG. 5B, in the seam welding, the surface a can be kept beautiful by adopting a disk-shaped seam welding electrode 72 having a large contact area on the surface a side and performing welding while rotating. .

  The code | symbol 73 in FIG.5 (c) shows the electrode for one side seam welding. Reference numeral 74 denotes a flat back electrode. As shown in FIG. 5 (c), in one-side seam welding, a flat back electrode 74 is employed on the surface a side, and welding is performed while rotating the electrode 73 on the surface b side (so-called one-side seam welding). The surface a can be kept beautiful.

In spot welding, a flat back electrode or an electrode having a large radius of curvature at the tip can be used to keep the electrode surface without leaving any traces of electrodes.
It is preferable that the 2nd molded object 21 is provided in a 30 to 80% area | region in the longitudinal direction including the center part of the longitudinal direction of a 1st molded object. This is because if this ratio exceeds 80%, the reinforcement per unit area other than the central section where the bending moment increases at the time of three-point bending deformation, the performance per weight decreases, and conversely if it is less than 30%, This is because the effect is not fully exhibited.

  As shown in FIG. 1, the second molded body 21 is preferably provided on the inner surface of the first molded body 11 from the viewpoint of improving the appearance quality, but the first molding is performed at a portion where the improvement in the appearance quality is not a problem. It may be provided on the outer surface of the body 11.

  In the present invention, the cross-sectional circumferential length of the first vertical wall portion 21 a of the second molded body 21 and / or the cross-sectional circumferential length of the second vertical wall portion 21 e is the first circumferential length of the first molded body 11. It is 30 to 80% of the cross-sectional peripheral length of the vertical wall portion 11a and / or the cross-sectional peripheral length of the second vertical wall portion 11e. Here, the “peripheral length of the cross section of the vertical wall portion” means the R-stop of the two ridge line portions (11b, 11f), (11d, 11h), 21b, 21d continuous to the vertical wall portions 11a, 11e, 21a, 21e. It means the distance between positions.

Thereby, the peak load per unit mass of the structural member for automobile body can be significantly increased. The reason for this will be explained.
6 (a) and 6 (b) are explanatory views schematically showing the state of deformation when the B pillar 10 which is a structural member for an automobile body according to the present invention undergoes three-point bending deformation. 6A shows that the first molded body 11 has a cross-sectional circumferential length of the first vertical wall portion 21a of the second molded body 21 and / or a sectional circumferential length of the second vertical wall portion 21e. FIG. 6B shows a case where the cross-sectional circumferential length of the first vertical wall portion 11a and / or the cross-sectional circumferential length of the second vertical wall portion 11e is 20%. The cross-sectional peripheral length of the first vertical wall portion 21a and / or the cross-sectional peripheral length of the second vertical wall portion 21e is the cross-sectional peripheral length of the first vertical wall portion 11a of the first molded body 11 and / or Or it is a case where it is 50% of the cross-sectional circumference of the 2nd vertical wall part 11e.

  In the three-point bending deformation of a structural member having a hat cross section, first, after the ridgeline portion is plastic buckled in the direction of opening in the cross section, the upper portion of the vertical wall portion is bent and deformed while generating plastic buckling. Peak load occurs. At this time, if the ridge line portion is reinforced, the opening of the ridge line portion is suppressed, and thereby the deflection of the vertical wall portion is suppressed, so that the plastic buckling limit is improved and the peak load is improved. Further, when the vertical wall portion is reinforced, the plastic buckling load of the vertical wall portion is directly improved, and the peak load is increased.

  However, as shown in FIG. 6A, the cross-sectional circumferential length of the first vertical wall portion 21 a of the second molded body 21 and the cross-sectional circumferential length of the second vertical wall portion 21 e are those of the first molded body 11. When the cross-sectional peripheral length of the first vertical wall portion 11a is smaller than 30% with respect to the cross-sectional peripheral length of the second vertical wall portion 11e, the occurrence region of deflection is the vertical wall portion 21a of the second molded body 21; This occurs at the end of 21e, and local plastic buckling occurs in the first molded body 11 with this end as a boundary. Therefore, the ratio is desirably 30% or more. On the other hand, when the ratio exceeds 80%, the portions other than the upper portions of the vertical wall portions 11a and 11 that are closely related to the peak load are also reinforced, and an increase in the peak load more than the weight increase due to the reinforcement cannot be expected. For this reason, the ratio is desirably 80% or less.

  That is, in the structure shown in FIG. 6A, the ridge line portions 11b and 11e overlapped by bending and folding of the vertical wall portions 11a and 11e are easy to open, and the spot welded portion is easily broken during collision deformation. In the structure shown in FIG. 6 (b), the opening of the ridge portions 11b and 11e becomes small due to the effect of suppressing the deflection, and the spot welded portion is hardly broken, and more stable collision performance is obtained. Thus, according to the present invention, the cross-sectional circumferential length of the first vertical wall portion 21a in the second molded body 21 and / or the cross-sectional circumference of the second vertical wall portion 21e in the second molded body 21. The length is 30 to 80% of the sectional circumferential length of the first vertical wall portion 11a in the first molded body 11 and / or the sectional circumferential length of the second vertical wall portion 11e in the first molded body 11. As a result, high collision energy absorption performance can be obtained.

  The ratio between the thickness of the first molded body 11 and the thickness of the second molded body 21 is preferably 0.5 to 1.5. If this ratio is less than 0.5, the contribution to improving the bending crush performance is small. On the other hand, if this ratio is greater than 1.5, the vertical wall portions 11a and 11e are likely to buckle prematurely for the reasons described later. This is because the peak load performance per weight decreases.

  Further, the cross-sectional circumferential lengths h2 and h1 of the first vertical wall portion 21a and the second vertical wall portion 21e of the second molded body 21, and the first vertical wall portion and the second vertical wall portion, respectively. The plate thicknesses t1 and t2 preferably satisfy the relationship of 0.2 (t2 / t1) +0.2 <h2 / h1 <0.2 (t2 / t1) +0.4. This is because early buckling of the vertical wall portion is suppressed.

  When the ratio of the plate thickness t2 of the vertical wall portions 21a and 21e of the second molded body 21 and the plate thickness t1 of the vertical wall portions 11a and 11e of the first molded body 11 is increased, the opening deformation of the ridge line is strongly restrained. Larger vertical compressive stress acts on the vertical wall portions 11 a and 11 e of the first molded body 11. At this time, local plastic buckling occurs in the vicinity of the end of the second molded body 21 after the vertical wall portions 11a and 11e of the first molded body 11 are elastically buckled. As a result, h2 / h1 needs to be increased as the plate thickness ratio increases.

The second molded body 21 is configured as described above.
[Third molded body 31]
The 3rd molded object 31 is a press-formed object of a steel plate, and is a B pillar inner panel. Since the 3rd molded object 31 bears the function which reinforces the 1st molded object 11 which is a main body, depending on the case, it may not be a press molded object, as shown in FIG.1 (b). It may be a closing plate.

It is preferable that the B pillar inner panel which is the third molded body 31 has a small bulging dimension to the indoor side in order to secure a wide indoor space.
The third molded body 31 is well-known and commonly used for this type of B pillar, and thus further explanation is omitted.

  FIG. 7A to FIG. 7E are explanatory views schematically showing various cross-sectional shapes of the B pillar 10. A second molded body (not shown) is joined to the inner surface of the first molded body 11 in FIGS. 7A to 7E by welding. The same reference numerals indicate the same parts.

  The B pillar 10 shown in FIG. 7A includes a first and second ridge line portions 28 and 28 that connect one surface 26 and the other one surface 27 and 27, one surface 29 and 29, and the other surface. The third and fourth ridge line portions 30, 30 connecting the one surface 27, 27 are provided. The B pillar 10 may be used alone depending on circumstances.

  B pillar 10 shown in Drawing 7 (b) shows an example provided with the 3rd fabrication object joined to at least one ridgeline part of the 1st and 2nd ridgeline parts 28 and 28. FIG. The B pillar 10 may constitute an automobile component together with a flat closing plate 31 that is a third molded body spot-welded via one surface (flange) 29, 29.

  The B pillar 10 shown in FIG. 7 (c) includes a first molded body 11 and another first molded body 11 as the third molded body 31 on one surface (flange) 29, 29. It may be spot welded via a combination to constitute an automobile component.

  The B pillar 10 shown in FIG. 7D includes a first and second ridge line portions 28 and 28 that connect one surface 26 and the other one surface 27 and 27, one surface 29 and 29, and the other surface. The third and fourth ridge line portions 30 and 30 connecting the one surface 27 and 27, and the fourth and fifth ridge line portions 33 connecting the one surface 29 and 29 and the other one of the surfaces 32 and 32, 33. The B pillar 10 may be used alone.

  Further, the B pillar 10 shown in FIG. 7 (e) has a flat closing plate 31 spot-welded via one surface (flange) 29, 29 of the first molded body 11 shown in FIG. 7 (e). You may comprise a motor vehicle component.

The internal angles (angle θ illustrated in FIG. 7A) of the ridge lines 28, 30, and 33 do not have to be 90 degrees, and may be a predetermined angle required for the B pillar 10.
In the illustrated example, the ridge line portion is provided so as to be symmetrical as a whole, but may be asymmetrical.

  FIG. 8A is an explanatory view showing a situation where the second molded bodies 21 and 21 are welded to the outer surface of the first molded body 11 of the B pillar 10 shown in FIG. 7A, respectively. FIG. 8B is an explanatory diagram illustrating a situation where the second molded bodies 21, 21, 21, and 21 are welded to the outer surface of the first molded body 11 of the B pillar 10 illustrated in FIG. (C) shows the second molded bodies 21-1 and 21-1 extending from the ridge line portions 28 and 28 to the ridge line portions 30 and 30 on the outer surface of the first molded body 11 of the B pillar 10 shown in FIG. It is explanatory drawing which shows the condition which welded the 2nd molded object 21-2, 21-2 to the ridgeline part 33, 33 while welding. In the drawing, the welded portions provided on the ridge line portions 28, 30, 33 are omitted for the sake of clarity.

  As will be described later, in the present invention, the blank which is the material of the second molded body 21 is welded to the blank which is the material of the first molded body 11 by welding, and then press molding or roll molding is performed. Is preferred. That is, it is preferable that the first molded body 11 and the second molded body 21 are molded integrally without a gap.

  As shown in FIG. 8A to FIG. 8C, the second molded body 21, 21-1, 21-2 is at least the ridge line portions 28, 30, 33 of the first molded body 11. It has dimensions that can cover the entire region in the circumferential direction of the cross section. As shown in the enlarged view in FIG. 8A, when the internal angle of the ridge line portions 28, 30, 33 is θ (rad) and the curvature radius is R (mm), the cross-sectional circumference of the ridge line portions 28, 30, 33 Since the length in the direction is Rθ (mm), the width of the second molded body 21 exceeds Rθ (mm). In consideration of the shape of the actual molded member, for example, the internal angle θ is not less than 60 degrees and not more than 120 degrees.

  FIGS. 8A and 8C show an example in which the second molded body 21 is provided on the outer peripheral surface of the ridge line portion 28 of the first molded body 11, and FIG. The example which provided the molded objects 21-1 and 21-2 in both the outer peripheral part and the internal peripheral surface of the ridgeline parts 28 and 30 of the 1st shaping body 11 is shown. A mode in which a reinforcing material is provided on both the outer peripheral surface and the inner peripheral surface of one ridge line portion is also conceivable. Here, “outer peripheral surface” and “inner peripheral surface” refer to the convex surface and concave surface of the ridge line part, respectively.

  The width (length in the circumferential direction of the cross section) of the welded portion 22 for welding the second molded bodies 21, 21-1, 21-2 to the ridge line portions 28, 30, 33 of the first molded body 11 is as follows. In particular, as long as the second molded bodies 21, 21-1, 21-2 are not largely separated from the ridges 28, 30, 33 of the first molded body 11 by a load applied during press molding, which will be described later. There is no need. However, it is needless to say that it is preferable not to peel even when subjected to a large load deformation. For example, when the welded portion 22 is a spot welded portion, the nugget diameter of the welded portion 22 is the thickness of the second molded body 21. When t (mm), it is preferably 3√t (mm) or more. As described above, the width of the welded portion 22 is preferably such that the ratio of the ridgeline portions 28, 30, and 33 to the length Rθ in the circumferential direction of the cross section of the ridgeline portions 28, 30, and 33 is large so that the B pillar 10 maintains desired characteristics. A plurality of welded portions 22 may exist on one ridge line portion.

  The welded portion 22 is provided between the center position of each ridge line portion 28, 30, 33 in the circumferential direction of the cross section and the position at a distance of at least 50% of the cross section circumferential length of each ridge line portion 28, 30, 33. Is desirable. Thereby, the effect of the present invention can be obtained with certainty.

  In addition, the entire width of the welded portion 22 may not be included in the range of the length Rθ in the circumferential direction of the ridgeline portions 28, 30, 33. It is sufficient that at least a part of the welded portion is included in the ridge line portion.

  2nd molded object 21, 21-1, 21-2 is when the cross-sectional shape of B pillar 10 to the extension direction of each ridgeline part 28, 30, 33 of the 1st molded object 11 is constant, and does not change. As a matter of course, the effect of the present invention can be obtained by providing the ridge line portions 28, 30, 33 over the entire length in the extending direction.

  However, in many actual B pillars 10, the cross-sectional shape is not constant depending on the position in the extending direction of each ridge line portion 28, 30, 33. In this case, there is a region having a small cross-sectional area that is most easily deformed when the B pillar 10 receives a load in the axial crushing direction, for example. Therefore, it is effective to provide the second molded bodies 21, 21-1, 21-2 at least in this region. Even if the second molded bodies 21, 21-1, and 21-2 are not provided on the entire length in the axial direction of the B pillar 10, the second molded bodies 21, 21-1, and 21-2 are formed in an area having a small cross-sectional area. By providing, the effect of this invention can be acquired more reliably. Of course, a larger effect can be obtained by providing the second molded bodies 21, 21-1 and 21-2 over the entire length of the B pillar 10 in the axial direction.

  What is necessary is just to set suitably arrangement | positioning of the welding part to the extension direction of the ridgeline parts 28, 30, 33 in the 1st molded object 11 according to the moldability at the time of shaping | molding, and the characteristic requested | required of a shaping | molding member. What is necessary is just to set suitably the shape of the welding part, such as a dotted | punctate form, a linear form, and the curve form, the arrangement number, and the dimension (length) of a welding part. Moreover, you may use a spot-like welded part and a linear welded part together, and may use a linear welded part and a curved welded part together.

  Here, the “extending direction” of the ridge line portion refers to the longitudinal direction, that is, the axial direction since the ridge line portion is provided along the longitudinal direction of the first molded body 11. In addition, the “cross-sectional shape of the ridge line portion” is a shape in a cross-section orthogonal to the longitudinal direction.

  Since the B pillar 10 includes the second molded body 21 welded in a range including the ridge line portion 11b of the first molded body 11, for example, in the conventional three-point bending, the ridge line portion 11b is not joined. Since the reinforced ridgeline portion 11b has high rigidity and high strength as compared with the case of the above, the ridgeline portion 11b exhibits high bending strength from the initial stage of deformation, and the deformation amount at the ridgeline portion 11b is higher than that of the conventional case. Become smaller. For this reason, the 1st vertical wall part 11a and the 2nd vertical wall part 11e can bear a load effectively with respect to a bending stress, As a result, a high bending buckling load can be obtained. For this reason, according to this invention, the absorption characteristic of the impact energy of a shaping | molding member improves.

  For this reason, according to the B-pillar 10, it is possible to bear an impact load which is a cylindrical automobile component and is loaded in a direction substantially orthogonal to the axial direction, and absorbs impact energy at the time of the three-point bending. It becomes possible to enhance the characteristics.

FIG. 9A to FIG. 9D are explanatory views partially and schematically showing, in section, suitable positions for forming the welded portions 40 to 42 in the B pillars 44 to 47.
FIG. 9A shows a B pillar 44 that bears an impact load applied in the axial direction, and a range in which the welded portions 40 to 42 are included in 50% of the cross-sectional circumferential length of the ridgeline portion Rθ (in the drawing, 1 / 2Rθ) at least.

  FIG. 9B shows a B pillar 45 that bears an impact load (σ, indicated by a white arrow in the figure) loaded in a direction orthogonal to the axial direction, and a part of the welds 40 to 42 is formed. It is preferable that it exists in the position concerning the R terminal part on the side wall side.

FIG.9 (c) shows the B pillar 46 which bears the impact load applied to the axial direction and two directions of a direction orthogonal to an axial direction with one welding part.
Furthermore, FIG.9 (d) shows B pillar 47 which each provides and bears the welding part according to each load direction on the same cross section.

  Thus, according to the present invention, the B-pillar outer panel 11 suitable for use in an automobile component member, which can be manufactured at low cost, has excellent dimensional accuracy, and has excellent three-point bending characteristics, and A B-pillar 10 can be provided.

2. Manufacturing method of structural member for automobile body according to the present invention The B pillar, which is a structural member for an automobile body according to the present invention, is not manufactured by a specific manufacturing method. For example, the first molded body 11 and the first molded body Each of the two molded bodies 21 is individually press-molded into a predetermined shape, and the first molded body 11 and the second molded body 21 after the press molding are arranged in a predetermined position so as to adhere to each other and overlap without any gaps. After that, it may be manufactured by appropriate means such as welding, but it is necessary to sufficiently increase the dimensional accuracy of each of the first molded body 11 and the second molded body 21 and the mass productivity is good. Absent. Therefore, a manufacturing method capable of ensuring high productivity and good quality will be described below.

  First, a part of the first vertical wall portion, the first ridge line portion, the bottom portion, the second ridge line portion, and the second vertical wall portion in the first blank that is the material of the first molded body 11. The welded portion 22 is formed on the first molded body and the second molded body by bonding the second blank, which is the material of the second molded body 21, to the first molded body and the second molded body by being brought into close contact with each other.

Next, the first blank welded to the second blank is press-molded.
Under the present circumstances, it is preferable to press-mold, after heating the 1st blank which welded the 2nd blank to the temperature of Ac ₃ point or more. According to so-called hot press forming, it is possible to reliably form a desired shape in both the first formed body 11 and the second formed body 21 while suppressing the occurrence of breakage and wrinkles due to press forming. Because.

  More specifically, in order to manufacture the B pillar 10, according to the first aspect, the first molded body is prepared in advance by performing bending molding by press molding or roll molding. At this time, the press forming and roll forming performed in advance may be performed hot or cold. In this way, the first molded body molded in advance is arranged with the second molded body which is also bent and molded in the same shape, and the two are welded in a state where they are closely adhered and overlapped, At that position. The arrangement of the welds at this time is as already described in detail, and the various means already described can be appropriately selected and used as the welding means.

  As described above, according to the present invention, the molded member can be manufactured by simple means, and if the region where the reinforcing material is provided is a ridge line portion, the region can be locally resisted by simply providing it at an arbitrary portion. Since the impact property can be greatly improved, when such a molded member is used as the B pillar 10, it is possible to simultaneously satisfy the contradictory properties of reducing the weight of the vehicle body and improving the impact resistance.

  According to another aspect of the present invention, in order to manufacture the B pillar 10 according to the present invention, first, a flat first blank that is a material of the first molded body 11 and a second molded body 21. The plate-like second blank, which is a material of the above, is brought into close contact with each other without any gaps.

  At this position, the first blank and the second blank are welded by any of the various welding methods described above to produce a flat plate-shaped welding member. The arrangement of the welded portion and the method for forming the welded portion at this time are as described above.

  With respect to this flat plate-shaped welding member, the range in which the second blank exists is a part of the first vertical wall portion 11a of the first molded body 11, the first ridge line portion 11b, the bottom portion 11c, the second portion. Press molding or roll molding is performed so as to be the ridge line portion 11d and the second vertical wall portion 11e. Thereby, the shaping | molding member which concerns on this invention is manufactured. The molding at this time may be either cold, hot or either. It can be determined appropriately according to the type of material and welding means.

  The inventors have spot welded two high strength steel plates (plate thickness 0.7 to 2.0 mm) of 440 to 980 MPa, and the center of the spot weld formed in this way is A number of press molding tests were performed to perform the 90 ° bending process so as to be positioned at the apex of the ridge line part having a radius of curvature of 3 mm, and it was confirmed whether or not the spot welded part was broken by the bending process. It was confirmed that no cracking occurred.

Further, in the present invention, it is possible to perform press molding (roll molding) after heating the flat plate-shaped welding member to a temperature of Ac ₃ points or higher, that is, even if the press molding is so-called hot press molding. can get. Thereby, it is possible to manufacture a hot press-formed member having higher strength while improving press formability.

  When the hot press-formed member is made of a high-strength material, so-called HAZ softening may occur in the welded part. However, if a flat plate-shaped welded member is manufactured by the hot press forming process, the softened part generated during welding Quenching hardening is obtained, and there is no HAZ softened portion, and a molded member in which the base material and the welded portion have the same strength (hardness) can be obtained.

The steel plate used in the present invention is not particularly limited as long as it is a steel type and plate material that can be hot-pressed and hot-roasted by heating to Ac ₃ points or more, but the HAZ softening of the weld zone is Since the steel is due to martensite strengthening of steel, the contribution of the strengthening mechanism is large, and therefore, steel of 590 MPa class or higher (particularly, dual phase (DP) steel) causing HAZ softening is preferable, and still more preferably, 1500 MPa class. It is the above steel.

  Thereby, the structural member for an automobile body according to the present invention described above, specifically, the first molded body 11 having a hat-shaped cross-sectional shape and the second molded body 21 having a groove-shaped cross-sectional shape. The first molded body 11 includes at least a first vertical wall portion 11a, a first ridge line portion 11b continuous with the first vertical wall portion 11a, and a bottom portion 11c continuous with the first ridge line portion 11b. And a second ridge line part 11d continuous with the bottom part 11c and a second vertical wall part 11e continuous with the second ridge line part 11d, and the second molded body 21 is a first vertical wall part. 21a, a first ridge line part 21b continuous to the first vertical wall part 21a, a bottom part 21c continuous to the first ridge line part 21b, a second ridge line part 21d continuous to the bottom part 21c, and a second For a long automobile body having a second vertical wall portion 21e continuous to the ridge line portion 21d It is possible to produce a B-pillar 10 as an example of the concrete member.

The present invention will be described more specifically with reference to examples.
10A and 10B are explanatory views showing a numerical experimental model of the B pillar 10 according to the present invention. FIG. 10A is a trihedral view and FIG. 10B is a cross-sectional view.

  A numerical experimental model of the B pillar 10 according to the present invention shown in FIGS. 10A and 10B was created, and a three-point bending analysis was performed. A general-purpose dynamic explicit finite element analysis code was used for the analysis. For the deformation characteristics of the material, the strain rate dependence of the Cowper-Symmonds type was considered. The element size was equivalent to 2.5 mm.

  In addition, the resistance spot welding part couple | bonded the position of the both contact corresponded to a spot junction part with the beam element which made the nugget diameter 5.5mm. At this time, the deformation characteristic of the beam element was an elastic perfect plastic body with a yield stress of 1200 MPa.

  At this time, the first vertical length of the second molded body 21 with respect to the cross-sectional circumferential length of the first vertical wall portion 11a of the first molded body 11 and / or the cross-sectional circumferential length of the second vertical wall portion 21e. Examples 1-3 of the present invention in which the ratio of the cross-sectional peripheral length of the wall portion 21a and / or the cross-sectional peripheral length of the second vertical wall portion 21e is 30, 50, and 80%, and this ratio is 20% and 100%. Certain Comparative Examples 1 and 2 and a conventional example using no second molded body 21 were confirmed.

FIG. 11A is an explanatory view showing a situation of a three-point bending test, and FIG. 11B is an explanatory view showing a cross-sectional shape of the B pillar 10 of the present invention example.
As shown in FIGS. 10 and 11 (b), the B pillar 10 includes a first molded body 11, a second molded body 21, and a third molded body 31. The specifications of these constituent members 11, 21, 31 are listed below.

1st molded object 11: Steel plate for hot presses, plate thickness 1.6mm
Second compact 21: Hot press steel plate, plate thickness 1.6 mm
Third molded body 31: 590 MPa class high tensile strength, thickness 1.2 mm
Ratio of the hat cross section of the second molded body 21 to the longitudinal direction of the part of the first molded body 11: 66%
The spot hitting points are formed on the vertical wall portions 11a and 11e at intervals of 40 mm in the longitudinal direction of the component, at the bottom portion 11c at intervals of 40 mm in the longitudinal direction of the component, and at the ridge portions 11b and 11d at intervals of 40 mm in the longitudinal direction of the component. The phases of the portions 11a, 11e and the bottom portion 11c are matched, and the phases of the vertical wall portions 11a, 11e, the bottom portion 11c and the ridge line portions 11b, 11d are shifted by half wavelength.

  As shown in FIG. 11A, the B pillar 10 created above is supported at two points 62 and 63 at a support point interval of 550 mm, and the impactor 64 having a radius of 150 mm is placed at a center position in the longitudinal direction of the B pillar 10 by 500 mm. A forced displacement of / sec was given, and a forced displacement amount of 50 mm was given. At this time, the peak load per unit weight obtained by dividing the peak load up to 50 mm by the weight of the constituent members 11 and 31 was obtained.

  FIG. 12A is a graph showing the results of bending crush analysis of Invention Examples 1 and 2, Comparative Examples 1 and 2 and the conventional example, and FIG. 12B shows Invention Examples 2 and 3 and Comparative Example. It is a graph which shows the result of 2 bending crush analysis. Table 1 summarizes the peak loads per unit weight of Examples 1 to 3 of the present invention, Comparative Examples 1 and 2, and the conventional example.

  From the results shown in the graph of FIG. 12, according to Examples 1 to 3 of the present invention, the maximum load was significantly increased as compared with Comparative Examples 1 and 2 and the conventional example. It can be seen that the peak load per unit weight has increased significantly.

Fig.13 (a) is explanatory drawing which shows the test condition of one-hat three-point bending, FIG.13 (b) is explanatory drawing which shows the cross-sectional shape of one-hat three-point bending.
A numerical experimental model of the one-hat cross-section member 10 according to the present invention shown in FIGS. 13A and 13B was created, and a three-point bending analysis was performed. A general-purpose dynamic explicit finite element analysis code was used for the analysis. For the deformation characteristics of the material, the strain rate dependence of the Cowper-Symmonds type was considered. The element size was equivalent to 2.5 mm.

  Note that the resistance spot welded portion is a beam element having a nugget diameter of 5.5 mm, and the positions of both contacts corresponding to the spot joint portion are coupled. At this time, the deformation characteristic of the beam element was an elastic perfect plastic body with a yield stress of 1200 MPa.

  As shown in FIG. 13A, the single hat member 10 created above is supported at two points 62 and 63 with a support point interval of 500 mm, and an impactor 64 having a radius of 150 mm is provided at the center position in the longitudinal direction of the single hat member 10. A forced displacement of 1000 mm / sec was given to the sample, and a forced displacement amount of 35 mm was given. At this time, the peak load per unit weight obtained by dividing the peak load up to 35 mm by the total weight of the first molded body 11 and the third molded body 31 was determined.

  As shown in FIG. 13 (b), the single hat member 10 is composed of a first molded body 11, a second molded body 21, and a third molded body 31. The specifications of these constituent members 11 to 31 are listed below.

First molded body 11: non-plated steel sheet for hot pressing, plate thickness 1.6 mm, width 120 mm, length 600 mm
Second molded body 21: non-plated steel plate for hot pressing, plate thickness 1.6 mm, width 120 mm, length 600 mm
Third molded body 31: 780 MPa class non-plated steel plate, plate thickness 1.8 mm, width 120 mm, length 600 mm
FIG. 14A is an explanatory view showing the spot hitting positions of Examples 1 to 4 of the present invention, and FIG. 14B is an explanatory view showing the spot hitting position of Example 5 of the present invention.

  As shown in FIG. 14A, the spot hitting points were formed on the vertical wall portions 11a and 11e of the first molded body 11 at intervals of 20 mm in the component longitudinal direction and at the bottom portion 11c at intervals of 40 mm in the component longitudinal direction, respectively. . The phases of the vertical wall portions 11a and 11e and the bottom portion 11c were matched. This was designated as Invention Examples 1 to 4.

  In addition, as shown in FIG. 14B, a structure in which the striking positions of the vertical wall portions 11a and 11e are staggered in the height direction is added. The interval in the longitudinal direction was 20 mm. This was designated as Invention Example 5.

  The peak load per unit weight is maximized when the ratio of the thickness of the second molded body 21 to the thickness of the first molded body is 0.5, 1.0, and 1.5. The ratio of the cross-sectional peripheral lengths of the vertical wall portions 21a and 21e of the second molded body 21 and the vertical wall portions 11a and 11e of the first molded body 11 was determined at 0.1 pitch.

  The results are summarized in Tables 2 and 3.

  From Table 2, h2 / h1 at which the maximum peak load per unit load is obtained increases as the ratio of the thickness t2 of the second molded body 21 and the thickness t1 of the first molded body 11 increases. I understand. At this time, it was found that h2 / h1 at which the maximum peak load per unit load is obtained is expressed by the formula: h2 / h1 = 0.2 (t2 / t1) +0.3.

From Table 3, it can be seen that the peak load per unit weight is greater in the staggered arrangement of the striking points of the vertical wall portion 11a than in one row.
Furthermore, the relationship between the crushing stroke and the crushing load per unit weight in Examples 4 and 5 of the present invention is shown in a graph in FIG.

  From the graph of FIG. 15, it can be seen that in the staggered arrangement, the load continues to increase even at 25 mm or more where the crushing stroke has sufficiently progressed, and a high peak load is exhibited. This is because the hitting point above the vertical wall portion 11a is located at the bending deformation portion of the vertical wall portion 11a, and directly improves the strength of the vertical wall portion 11a.

DESCRIPTION OF SYMBOLS 1 Automobile body 2 B pillar 3 Side sill 4 Roof rail side 5 Bumper reinforcement 6 Belt line 7 Molded body 7a One surface 7b Another one surface 7c Ridge part 8 Closing plate 9 Structural member for vehicle body (front side member)
10 Automotive body structural members (B pillar)
11 First molded body (main body, B pillar outer panel)
11a 1st vertical wall part 11b 1st ridgeline part 11b-1 part 11b-2 for which axial crushing performance is required part 11c for which bending deformation performance is required bottom part 11d 2nd ridgeline part 11e 2nd vertical wall part 11f 3rd ridgeline part 11g 1st flange part 11h 4th ridgeline part 11i 2nd flange part 11j 5th ridgeline part 11k 1st surface part 11l 6th ridgeline part 11m 2nd surface part 21 2nd Molded body (reinforcing member)
21a 1st vertical wall part 21b 1st ridgeline part 21c bottom part 21d 2nd ridgeline part 21e 2nd vertical wall part 21-1 1st molded object element 21-2 2nd molded object 22 Bonding part 26 One surface 27 Other one surface 28 First and second ridge line portions (ridge line portions)
29 One side (flange)
30 3rd, 4th ridgeline part 31 3rd molded object (main body, B pillar inner panel)
32 Other surface 33 Fourth and fifth ridge portions 35 Second molded bodies 40 to 42 Welded portions 44 to 47 B pillar 70 Laser welding machines 71 and 72 Seam welding electrode 72 Seam welding electrode 73 One side seam Welding electrode 74 Flat back electrode

Claims (16)

A long automobile body structural member comprising a first molded body that is a molded body of a metal plate and a second molded body that is a molded body of the metal plate and has a joint portion with the first molded body. Because
The first molded body includes at least a first vertical wall portion, a first ridge line portion continuous with the first vertical wall portion, a bottom portion continuous with the first ridge line portion, and a bottom portion thereof. Having a hat-shaped cross-sectional shape by having a continuous second ridge line part and a second vertical wall part continuous to the second ridge line part;
The second molded body is continuous with the first vertical wall portion, the first ridge line portion that continues to the first vertical wall portion, the bottom portion that continues to the first ridge line portion, and the bottom portion. Having a groove-shaped cross-sectional shape by having a second ridge line part and a second vertical wall part continuous to the second ridge line part,
The first vertical wall portion of the second molded body is in close contact with the first vertical wall portion of the first molded body, and the first ridge line portion of the second molded body is the first ridge line portion. In close contact with the first ridge line portion of the molded body, the bottom portion of the second molded body is in close contact with at least part of the bottom portion of the first molded body, and the second ridge line portion of the second molded body. Is in close contact with the second ridge line portion in the first molded body, and the second vertical wall portion in the second molded body is in close contact with the second ridge line portion in the first molded body, And the cross-sectional circumferential length of the first vertical wall portion in the second molded body and / or the cross-sectional circumferential length of the second vertical wall portion in the second molded body are the same as those in the first molded body. The cross-sectional circumference of the first vertical wall and / or the cross-sectional circumference of the second vertical wall in the first molded body A structural member for an automobile body characterized by being 30 to 80% of the length. The second molded body is constituted by a first molded body element and a second molded body element;
The first molded body element is formed on at least a part of a first vertical wall portion of the first molded body, a first ridge line portion of the first molded body, and a bottom portion of the first molded body. And the second molded body element includes: a second vertical wall portion of the first molded body; a second ridge line portion of the first molded body; and the first molded body element. 2. The structural member for an automobile body according to claim 1, wherein the structural member is closely bonded to at least a part of a bottom portion of the molded body.   The ratio of the plate thickness of the first molded body to the plate thickness of the second molded body is 0.5 to 1.5, for an automobile body according to claim 1 or 2. Structural member.   The cross-sectional peripheral length (h1) of the first vertical wall portion and / or the cross-sectional peripheral length (h2) of the second vertical wall portion of the second molded body, and the plate thickness (t1) of the first vertical wall portion ) And / or the plate thickness (t2) of the second vertical wall portion satisfies the relationship of 0.2 (t2 / t1) +0.2 <h2 / h1 <0.2 (t2 / t1) +0.4 The structural member for an automobile body according to any one of claims 1 to 3, wherein the structural member is for a vehicle body.   The second molded body is formed from the one end portion of the first molded body from a position that is 30% of the total length of the first molded body from one end portion in the longitudinal direction of the first molded body. The structural member for an automobile body according to any one of claims 1 to 4, wherein the structural member is provided in a range up to a position that is 80% of a total length of the body.   6. The structural member for an automobile body according to claim 1, wherein the second molded body is provided on an inner surface or an outer surface of the first molded body.   The automobile body structural member according to any one of claims 1 to 6, wherein the joint portion is provided intermittently or continuously in a longitudinal direction of the first molded body. .   The said joining part is provided in a part or all of the longitudinal direction of a said 2nd molded object, The structural member for motor vehicle bodies described in any one of Claim 1- Claim 7 characterized by the above-mentioned.   9. The structural member for an automobile body according to any one of claims 1 to 8, wherein the joint portion is a spot welded portion, a seam welded portion, a laser welded portion, or a plasma welded portion.   The structural member for an automobile body according to any one of claims 1 to 9, wherein the metal plate is a steel plate.   The vehicle body structural member according to any one of claims 1 to 10, wherein the first molded body is a B-pillar outer panel. A method for manufacturing a structural member for an automobile body according to any one of claims 1 to 11,
Part of the first vertical wall portion, the first ridge line portion, the bottom portion, the second ridge line portion, and the second vertical wall in the first blank that is a material of the first molded body The second blank, which is the material of the second molded body, is bonded by welding to a position that becomes a part of the part, and press molding or roll molding is performed on the first blank and the second blank that are joined. The manufacturing method of the structural member for motor vehicle body characterized by performing.   The method for manufacturing a structural member for an automobile body according to claim 12, wherein the metal plate is a steel plate. 14. The manufacturing method for a vehicle body structural member according to claim 13, wherein the press molding is performed in a state where the joined first blank and second blank are heated to a temperature of Ac ₃ points or higher. Method. A method for manufacturing a structural member for an automobile body according to any one of claims 1 to 11,
By performing press molding or roll molding on the first blank which is the material of the first molded body, at least the first vertical wall portion, the first ridge line portion, the bottom portion, and the second ridge line. The first molded body having the portion and the second vertical wall portion is manufactured, and the first blank is subjected to press molding or roll molding on the second blank which is a material of the second molded body. After manufacturing the second molded body having the vertical wall portion, the first ridge line portion, the bottom portion, the second ridge line portion, and the second vertical wall portion,
A method for manufacturing a structural member for an automobile body, wherein the first molded body and the second molded body are overlapped and joined at a predetermined position.   The method of manufacturing a structural member for an automobile body according to any one of claims 12 to 15, wherein the first molded body is a B-pillar outer panel.

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