JP2018140411A - Panel member for motor vehicle - Google Patents

Abstract

Even when three or more plate materials including two types of plate materials having different tensile strengths are bonded to each other, it is possible to suppress breakage (cracking) at the time of molding in a low strength plate material having low tensile strength. An automotive panel member is obtained. In a dissimilar material joint portion that joins a high-strength steel plate and a low-strength steel plate on a panel member, a filler material is used at the time of joining by a laser, thereby strengthening the joining in the dissimilar material joint portion. The portion 37 is provided, and the bonding strength can be increased. As a result, the amount of elongation on the dissimilar material joint part 36 side can be reduced in the low-strength steel plate 32 via the dissimilar material joint part 36. Thereby, the deformation amount in the panel member 50 can be reduced, the stress concentration acting on the low-strength steel plate 32 is alleviated, and the panel member 50 can be prevented from being broken (cracked) during forming. [Selection] Figure 2

Description

  The present invention relates to an automotive panel member.

  In Patent Document 1 below, a welding line by butt welding is used in a panel member formed by butt welding two steel plates (plate materials) having different plate thicknesses into an L shape, an inverted L shape, and a U shape. A technique is disclosed in which a corner of the welding line has a welded wire corner, and a quenching line is set with a laser on the thin plate side radially from the welded wire corner. And thereby, the strength of the thin plate side steel plate is improved, and the fracture (crack) that occurs on the thin plate side steel plate side at the time of drawing by press working is suppressed.

JP2015-016486A

  However, in the above prior art, two steel plates having different plate thicknesses are joined. For this reason, for example, when three or more steel plates including two types of steel plates having different tensile strengths are bonded to each other, the steel sheet having the lowest tensile strength (hereinafter referred to as “low-strength plate”) starts from the corner of the weld line. Even if laser hardening is performed in a radial manner, there is a possibility that a fracture (crack) may occur on the side of the low-strength plate at the time of forming due to the influence of the other two steel plates having a higher tensile strength than the low-strength plate. .

  In view of the above facts, the present invention takes into account the breakage (crack) at the time of molding in a low-strength plate having a low tensile strength even when three or more plates including two types of plates having different tensile strengths are joined together. It is an object to obtain an automotive panel member capable of suppressing the above.

  The automotive panel member according to claim 1 is joined via a first joint portion in a state of being adjacent to the metal first plate material, and is made of a metal second plate material having a lower tensile strength than the first plate material. And made of metal joined to the first plate member and the second plate member through a second joint portion that intersects the first joint portion in a state adjacent to the first plate member and the second plate member. One or more other plate materials, and a joint strengthening portion that is provided at least in the first joint portion among the first joint portion and the second joint portion and increases the joint strength of the first joint portion. doing.

  In the automotive panel member according to claim 1, the first metal plate and the second metal plate having a lower tensile strength than the first plate are adjacent to each other via the first joint portion. It is joined. In addition, one or more other third plate members made of metal in a state adjacent to the first plate member and the second plate member are connected to the first plate member and the second plate via a second joint portion that intersects the first joint portion. It is joined to the plate material. And among the 1st junction part and the 2nd junction part, the junction strengthening part which makes high the joint strength of the 1st junction part is provided in the 1st junction part at least.

  Generally, when a plate material having different tensile strength is pulled under the same conditions, a plate material having a low tensile strength has a larger elongation than a plate material having a high tensile strength. Based on this, for example, in a panel member for an automobile (hereinafter simply referred to as “panel member”), a first plate member and a second plate member (tensile strength; first plate member> second) arranged adjacently and having different tensile strengths. The case where the plate material) and the other third plate material are joined in a trifurcated manner in a state of abutting each other will be considered.

  In this case, when a tensile force is applied along a direction orthogonal to the arrangement direction of the first plate member and the second plate member arranged adjacent to each other, the first plate member, the second plate member, and the third plate member are joined. In the two joint portions, due to the difference in elongation between the first plate material and the second plate material, the position of the second joint portion that joins the first plate material and the third plate material, and the second plate material and the third plate material are joined. The position of the second joint portion to be displaced is shifted in the pulling direction. As a result, the panel member is deformed into an S shape. That is, the moldability of the panel member is deteriorated at the time of forming (during forming by press working).

  Further, in the panel member, when the position of the second joint portion that joins the first plate member and the third plate member and the position of the second joint portion that joins the second plate member and the third plate member are shifted in the tensile direction, The intersection of the first joint and the second joint is a starting point where the position of the second joint is shifted in the pulling direction. For this reason, on the top side of the second plate member, which is a lower-strength plate member than the first plate member, stress is concentrated during the formation of the panel member, and local elongation (necking) or breakage (cracking) may occur.

  On the other hand, in this invention, a joining reinforcement | strengthening part is provided in a 1st junction part at least among a 1st junction part and a 2nd junction part, and the joint strength of the said 1st junction part is made high. Thus, the tensile strength in the said 1st junction part can be made high by raising the joining strength of a 1st junction part. As a result, the amount of elongation on the first joint portion side of the second plate member can be reduced via the first joint portion.

  Since the intersection of the first joint and the second joint is a starting point where the second joint is shifted in the pulling direction, at least the second joint can be reduced by reducing the amount of elongation on the first joint in the second plate. On the top side of the plate material, the amount of displacement in the tensile direction can be reduced between the first plate material and the second plate material. Thereby, the deformation amount in a panel member can be made small, the stress concentration which acts on a 2nd board | plate material is relieve | moderated, and the fracture | rupture (crack) at the time of shaping | molding can be suppressed in a panel member.

  That is, in the present invention, in three types of plate materials including a second plate material having a tensile strength lower than that of the first plate material, the first joint portion between the second plate material and the first plate material in which stress is concentrated when the panel member is molded or the like. To optimize the strength balance. In addition, the "top part of the 2nd board | plate material" here means the intersection of a 1st junction part and a 2nd junction part, and its peripheral part in a 2nd board | plate material.

  As described above, in the automotive panel member according to claim 1, even when three or more plate materials including two types of plate materials having different tensile strengths are joined to each other, the low strength with low tensile strength is low. The outstanding effect that the fracture | rupture (crack) at the time of shaping | molding in a board | plate material can be suppressed is acquired.

It is a top view which shows the panel member for motor vehicles based on this Embodiment. It is a partially expanded perspective view which shows the state by which the joining area | region A shown in FIG. 1 was expanded. (A) is sectional drawing of a junction part of the comparative example corresponding to (B), (B) is sectional drawing when cut | disconnecting along 3 (B) -3 (B) line | wire in FIG. It is. (A) is a partially enlarged perspective view corresponding to FIG. 2 showing a comparative example, and (B) is an explanatory diagram for explaining a problem in (A).

  Hereinafter, embodiments of an automotive panel member according to the present invention will be described with reference to the drawings. For convenience of explanation, an arrow FR appropriately shown in these drawings indicates a front side in the front-rear direction of the automotive panel member, an arrow RH indicates a right side in the width direction of the automotive panel member, and an arrow LH indicates an automotive panel member. The left side in the width direction is shown.

(Configuration of automotive panel members)
FIG. 1 shows a plan view of an automotive panel member (hereinafter simply referred to as “panel member”) 10 according to the present embodiment. The panel member 10 shown in FIG. 1 is divided into, for example, a central portion 12, a right side portion 14, and a left side portion 16 in the width direction of the panel member 10. And the center part 12 and the right side part 14 and the center part 12 and the left side part 16 are each joined to the width direction of the panel member 10 by the tailored blank method (it mentions later), and are integrated.

  In general, the tailored blank method is a method in which a plurality of metal plates (blank materials) having different materials and plate thicknesses are welded (joined) by laser welding or the like to form one metal plate. For example, it has the characteristic that the mechanical characteristics of one raw material can be partially changed by welding and integrating plate materials of different materials. Moreover, rigidity can be partially changed by welding and integrating plate materials having different plate thicknesses.

Here, the configuration of the panel member 10 will be briefly described.
As shown in FIG. 1, the front portion 22 and the rear portion (third plate member) 24 are disposed adjacent to each other in the center portion 12 in the width direction of the panel member 10 along the front-rear direction of the panel member 10. For example, a high-tensile steel plate material having a tensile strength of 590 MPa (so-called “590 material”) is used for the front portion 22 and the rear portion 24, and the front portion 22 and the rear portion 24 are connected via the same material joint portion 26. It is joined. In addition, the “same material joint” in the present embodiment refers to a joint when the tensile strengths of the steel plates arranged adjacent to each other are the same, and the “dissimilar material joint” refers to the steel plates arranged adjacent to each other. This refers to the joint when the tensile strengths of the two differ.

  Further, the right side portion 14 in the width direction of the panel member 10 is disposed so that the front portion 28, the center portion (first plate member) 30, and the rear portion (second plate member) 32 are adjacent to each other along the front-rear direction of the panel member 10. ing. The front portion 28 and the central portion 30 are made of ultra high strength steel plates having a tensile strength of 980 MPa (so-called “980 materials”), and the rear portions 32 are made of high strength steel plates having a tensile strength of 440 MPa (so-called “440 materials”). )) Is used. And the front part 28 and the center part 30 are joined via the same kind material joining part 34, and the center part 30 and the rear part 32 are joined via the dissimilar material joining part (first joining part) 36. ing.

  Further, the left side portion 16 in the width direction of the panel member 10 has a front portion 38, a central portion (first plate member) 40, and a rear portion (second plate member) along the front-rear direction of the panel member 10, similarly to the right side portion 14. 42 are arranged adjacent to each other. 980 materials are used for the front portion 38 and the central portion 40, and 440 materials are used for the rear portion 42. And the front part 38 and the center part 40 are joined via the same kind material joining part 44, and the center part 40 and the rear part 42 are joined via the dissimilar material joining part (first joining part) 46. ing.

  As described above, the center portion 12 in the width direction of the panel member 10 and the right side portion 14 are joined via the dissimilar material joint portion (second joint portion) 18, and the center portion in the width direction of the panel member 10. 12 and the left side part 16 are joined via a dissimilar material joint part (second joint part) 20.

  Further, in the panel member 10, the position of the same material joint portion 26 in the central portion 12 in the width direction, the position of the same material joint portion 34 in the right side portion 14, and the position of the same material joint portion 44 in the left side portion 16 are respectively the panel. The member 10 is displaced in the front-rear direction. Further, the position of the same material joint portion 26 in the central portion 12 in the width direction of the panel member 10, the position of the dissimilar material joint portion 36 in the right side portion 14, and the position of the dissimilar material joint portion 46 in the left side portion 16 are respectively the panel member. 10 is deviated in the front-rear direction.

  2 shows an enlarged perspective view in which the joining area A (panel member 50) of the panel member 10 in FIG. 1 is enlarged. As shown in this figure, in the panel member 50, three types of steel plates having different tensile strengths are joined in a trifurcated manner in a state of being adjacent to each other and butted against each other.

  As described above, the left part of the panel member 50 (the rear part (third plate member 24) 24 of the central part 12 of the panel member 10 shown in FIG. 1) is formed of 590 materials, and the right front part (FIG. 1) of the panel member 50. The center portion (first plate member) 30) of the right side portion 14 of the panel member 10 shown in FIG. Further, the right rear portion of the panel member 50 (the rear portion (second plate member) 32 of the right side portion 14 of the panel member 10 shown in FIG. 1) is formed of 440 materials.

  Therefore, in the following description, the left part of the panel member 50 shown in FIG. 2 is “medium strength steel plate 24”, the right front part of the panel member 50 is “high strength steel plate 30”, and the right rear part of the panel member 50 is “low”. It is referred to as “strength steel plate 32”. Note that the 440 material is generally a high-tensile steel plate, but here it is referred to as a “low-strength steel plate” for the sake of convenience by relative evaluation with the 590 material. Used in a different meaning than strength.

  Here, as an example, a steel plate with a thickness of 1.0 mm is used as the high-strength steel plate 30 and the medium-strength steel plate 24, and a steel plate with a thickness of 0.65 mm is used as the low-strength steel plate 32. . However, these plate thicknesses are not particularly limited to this.

  In the present embodiment, the high-strength steel plate 30 and the low-strength steel plate 32 are joined via the dissimilar material joint 36, and the high-strength steel plate 30 and the low-strength steel plate 32 and the medium-strength steel plate 24 are joined to the dissimilar material joint 18. However, the filler material 52 is used as a joining reinforcement material at the time of joining the high strength steel plate 30 and the low strength steel plate 32 at least on the dissimilar material joining portion 36 side.

  About a filler material, although it changes with kinds of board | plate material, here, the wire (Fe) to which C, Si, Mn etc. were added is used, for example. That is, the filler material is mainly composed of Fe and added with C, Si, and Mn. When the amount of C, Si, and Mn is increased, the bonding strength is increased.

(Operation and effect of automotive panel members)
In the present embodiment, as shown in FIG. 2, a filler material 52 is used at the time of joining by the laser 51 on the dissimilar material joining portion 36 side that joins the high-strength steel plate 30 and the low-strength steel plate 32. This increases the bonding strength at the dissimilar material joint 36.

  For example, FIG. 3A shows a case where the filler material 52 (see FIG. 2) is not used in the dissimilar material joint 108. In the dissimilar material joint 108, the high-strength steel plate 102 and the low-strength steel plate 104 are melted together by the heat of the laser 51 (see FIG. 2), mixed and cooled, and joined. The hardness is determined by the average of the additive element amount of the high-strength steel plate 102 and the additive element amount of the low-strength steel plate 104.

  On the other hand, FIG. 3B shows a case where the filler material 52 is used for the dissimilar material joint 36. In this case, in the dissimilar material joining portion 36, the filler material 52 is melted in addition to the high-strength steel plate 30 and the low-strength steel plate 32 by the heat of the laser 51 (see FIG. 2), and is mixed and cooled to be joined. (Different material joint 36). Therefore, in the dissimilar material joint part 36, the joining reinforcement | strengthening part 37 (part which the filler material 52 solidified) is provided, and it swells rather than the dissimilar material joint part 108 (the volume of a junction part is large).

  In the dissimilar material joint portion 36, the hardness is determined by the average of the additive element amount contained in the filler material 52 in addition to the additive element amount of the high-strength steel plate 30 and the additive element amount of the low-strength steel plate 32. Therefore, the dissimilar material joint 36 using the filler material 52 can have higher tensile strength than the dissimilar material joint 108 not using the filler material 52 (see FIG. 3A). That is, the amount of elongation on the dissimilar material joint portion 36 side of the low-strength steel plate 32 can be reduced via the dissimilar material joint portion 36.

  In general, when steel plates having different tensile strengths are pulled under the same conditions, a steel plate having a low tensile strength has a higher elongation than a steel plate having a high tensile strength. Based on this, for example, as shown in FIG. 4A, in the panel member 100, three high-strength steel plates 102, low-strength steel plates 104, and medium-strength steel plates 106 having different tensile strengths are adjacent to each other. Consider the case of joining in a fork shape.

  In this case, when the tensile force F acts along the direction orthogonal to the arrangement direction of the high-strength steel plate 102 and the low-strength steel plate 104, as shown in FIG. Due to the difference in elongation between the high-strength steel plate 106 and the high-strength steel plate 102, the position of the dissimilar material joint 110A where the medium-strength steel plate 106 and the high-strength steel plate 102 are joined, and the medium-strength steel plate 106 and the low-strength steel plate 104. The position of the dissimilar material joint 110B where the and are joined is shifted in the pulling direction.

  As a result, the panel member 100 is deformed into an S shape. That is, when the panel member 100 is formed by drawing or the like by press working, the formability of the panel member 100 is deteriorated. 4B shows the deformation of the panel member 100 larger than the actual amount in order to make the deformation of the panel member 100 easier to understand.

  4B, in the panel member 100, the position of the dissimilar material joint 110A where the medium-strength steel plate 106 and the high-strength steel plate 102 are joined, the medium-strength steel plate 106, and the low-strength steel plate 104. When the position of the dissimilar material joint 110B joined to each other is shifted in the tensile direction, the apex P ′ joined to the high-strength steel plate 102 and the medium-strength steel plate 106 on the low-strength steel plate 104 side (see FIG. 4A). ) Is a starting point where the position of the dissimilar material joint 110B is shifted in the pulling direction. For this reason, on the top 112 side of the low-strength steel plate 104, stress is concentrated when the panel member 100 is formed, and local elongation (necking) or fracture (cracking) may occur.

  On the other hand, in this embodiment, as shown in FIG. 2 and FIG. 3 (B), the filler at the time of joining by the laser 51 on the dissimilar material joining part 36 side for joining the high strength steel plate 30 and the low strength steel plate 32 is used. By using the material 52, the joining strengthening portion 37 is provided in the dissimilar material joining portion 36, and the joining strength can be increased. As a result, the amount of elongation on the dissimilar material joint part 36 side can be reduced in the low-strength steel plate 32 via the dissimilar material joint part 36.

  The intersection point P between the dissimilar material joint 36 and the dissimilar material joint 18 is a starting point where the dissimilar material joint 18 deviates in the tensile direction. Therefore, in the low-strength steel plate 32, the amount of elongation on the dissimilar material joint 36 side is reduced. By doing so, the amount of shift in the tensile direction can be reduced between the high-strength steel plate 30 and the low-strength steel plate 32 at least on the top 54 side of the low-strength steel plate 32. Thereby, the deformation amount in the panel member 50 can be reduced, the stress concentration acting on the low-strength steel plate 32 is alleviated, and the panel member 50 can be prevented from being broken (cracked) during forming.

  That is, in this embodiment, in three types of plate materials including a low strength steel plate 32 having a tensile strength lower than that of the high strength steel plate 30, the low strength steel plate 32 and the high strength steel plate 30 in which stress is concentrated when the panel member 50 is formed. In order to optimize the strength balance, the dissimilar material joint 36 is reinforced.

  Thus, even when three or more plate materials including two types of plate materials having different tensile strengths are joined to each other, a break (crack) at the time of forming in the low strength steel plate 32 having a low tensile strength is suppressed. be able to,

  The panel member 10 shown in FIG. 1 including the panel member 50 formed as described above is applied to, for example, a vehicle floor panel. When applied as a floor panel, although not shown, the central portion 12 in the width direction of the panel member 10 is a tunnel portion, and the right side portion 14 and the left side portion 16 are floor portions. For this reason, in press work, the center part 12 of the panel member 10 protrudes upwards. The panel member 10 can be applied to a door member in addition to the floor panel, and the size and configuration of the panel member 10 are not limited thereto.

  In general, when the strength of a steel plate is increased, the material of the steel plate changes, which increases the cost. Further, when the rigidity of the steel plate is increased, the plate thickness is increased, so that when the steel plate is applied as an automobile panel member, the weight of the automobile is increased, and the fuel consumption is deteriorated. In view of the above, the tensile strength and thickness of the steel plate are not limited to this embodiment, and are appropriately changed in consideration of the balance between strength and rigidity required for vehicle specifications.

  As described above, by applying the panel member 50 (see FIG. 2) in the present embodiment, the mechanical characteristics can be partially changed according to the specifications of the panel member 10 (see FIG. 1). Therefore, it is possible to reduce the weight of the vehicle and reduce the cost.

(Other embodiments)
In the above embodiment, as shown in FIG. 2, it is described that the filler material 52 is used in the dissimilar material joint portion 36 that joins the high-strength steel plate 30 and the low-strength steel plate 32 in the panel member 50. However, the present invention is not limited to this, and the filler material 52 may also be used in the dissimilar material joint 18 that joins the high-strength steel plate 30 and the low-strength steel plate 32 and the medium-strength steel plate 24.

  Further, in the present embodiment, it is referred to as “low-strength steel plate”, “medium-strength steel plate”, and “high-strength steel plate” for the sake of convenience by relative evaluation with other steel plates. The meaning is different from low strength, medium strength and high strength.

  Furthermore, in this embodiment, although the steel plate was mentioned as an example and demonstrated as a board | plate material used for the panel member 10, a board | plate material is not restricted to a steel plate. For example, a plate material formed of an aluminum alloy or the like may be used.

  In the present embodiment, for example, a plate material having a tensile strength of 980 MPa is used as the ultra-high-strength steel plate material, and a plate material having tensile strengths of 780 MPa, 590 MPa, and 440 MPa is used as the high-tensile steel plate material. Is not limited to these, and can be appropriately changed according to the vehicle type and the like.

  Here, in the present embodiment, an example is described in which materials having different tensile strengths are applied to three types of plate materials (steel plates), but the present invention is not limited to this. For example, the same material as the first plate material and the second plate material may be used for the third plate material.

  Furthermore, as shown in FIG. 1, in the joint portion including the dissimilar material joint portions 18 and 36, the straight line is used in the present embodiment. However, these joint portions are not limited to a straight line and may be curved. Good. Therefore, the shape of the steel plate is not limited to a rectangular shape.

  As described above, an example of the embodiment of the present invention has been described. However, the embodiment of the present invention is not limited to the above, and one embodiment and various modifications may be used in combination as appropriate. Needless to say, the present invention can be implemented in various forms without departing from the gist of the invention.

10 Panel members (Automotive panel members)
18 Dissimilar material joint (second joint)
20 Dissimilar material joint (second joint)
24 Medium strength steel plate (third plate)
30 High-strength steel plate (first plate)
32 Low strength steel plate (second plate)
36 Dissimilar material joint (first joint)
37 Joint strengthening part 40 High strength steel plate (first plate)
42 Low strength steel plate (second plate)
46 Dissimilar material joint (first joint)
50 Panel members (Automotive panel members)

Claims (1)

A second plate made of metal that is bonded to the first plate made of metal in a state adjacent to the first plate and has a lower tensile strength than the first plate, and
One or more metal members joined to the first plate member and the second plate member through a second joint portion intersecting the first joint portion in a state adjacent to the first plate member and the second plate member. Other third plate material,
A bonding strengthening portion that is provided at least in the first bonding portion and increases the bonding strength of the first bonding portion;
An automotive panel member having