Title of Invention: Tray and method for manufacturing the tray
Technical field
[0001]
The present invention relates to trays and tray manufacturing methods.
This application claims priority based on Japanese Patent Application No. 2020-017224 filed in Japan on February 4, 2020, the content of which is hereby incorporated by reference.
Background technology
[0002]
Conventionally, there has been a battery case that includes a resin battery tray with a metal frame on the outer wall and a battery cover that covers the battery tray.
prior art documents
patent literature
[0003]
Patent Document 1: JP 2011-124101 A
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0004]
However, conventional battery trays needed to ensure rigidity against crushing due to external force in order to protect the batteries placed on them. Therefore, the weight of the conventional battery tray may become excessive.
[0005]
An object of the present invention is to provide a robust and lightweight tray and a method for manufacturing the tray in view of the problems of the background art described above.
Means to solve problems
[0006]
The gist of the present invention is as follows.
[0007]
(1) A tray according to an aspect of the present invention is a tray comprising a bottom wall and a peripheral side wall erected from the outer periphery of the bottom wall, the tray including a high-strength portion having high tensile strength and and a low-strength portion having a tensile strength lower than that of the high-strength portion, wherein the low-strength portion is formed on the first sidewall inner surface of the first sidewall and the second sidewall inner surface of the second sidewall adjacent to each other forming a minor angle. A recessed portion is formed having a corner portion and a corner portion at the top surface of the bottom wall forming a minor angle with respect to each of the first side wall inner surface and the second side wall inner surface at the corner portion.
(2) In (1) above, the high-strength portion may be formed from the first side wall through the bottom wall to a third side wall facing the first side wall.
(3) In (1) or (2) above, an inner reinforcing member may be provided on the bottom wall, extending from the first side wall to a third side wall facing the first side wall.
(4) In (3) above, the inner reinforcing member may overlap the high-strength portion.
(5) In any one of (2) to (4) above, the first side wall and the third side wall may include an outer reinforcing member extending along the first side wall and the third side wall.
(6) A method for manufacturing a tray according to an aspect of the present invention is a method for manufacturing a tray including a bottom wall and a peripheral side wall erected from the outer periphery of the bottom wall, the tray having high tensile strength and high strength. and a low-strength portion having a lower tensile strength than the high-strength portion; A recessed portion having a corner portion at the second sidewall inner surface of the sidewall and a corner portion at the top surface of the bottom wall forming a minor angle with respect to each of the first sidewall inner surface and the second sidewall inner surface at the corner portion. and a forming step of pressing so as to form.
Effect of the invention
[0008]
According to the present invention, a robust and lightweight tray and a method for manufacturing the tray can be provided.
Brief description of the drawing
[0009]
1 is an explanatory diagram of a tray according to an embodiment; FIG.
2 is a perspective view of the tray according to the embodiment; FIG.
3 is a plan view of the tray according to the embodiment; FIG.
4 is a cross-sectional view taken along the arrow A in FIG. 3. FIG.
MODE FOR CARRYING OUT THE INVENTION
[0010]
Battery trays installed in vehicles (vehicle bodies) are required to have high rigidity so that they are not excessively crushed in the vehicle width direction against external forces caused by side collisions with obstacles, etc., in order to protect the mounted batteries. be done. At the same time, it is preferable that the battery tray provided in the vehicle be light in weight in order to improve the fuel consumption or power consumption of the vehicle.
[0011]
The tray of the present invention includes a bottom wall and peripheral side walls standing from the outer periphery of the bottom wall. The tray has a high strength portion with a high tensile strength and a low strength portion with a lower tensile strength than the high strength portion. The low-strength portion includes a corner portion of the peripheral sidewall having a first sidewall surface of the first sidewall and a second sidewall surface of the second sidewall forming an inferior angle to each other, and the first sidewall surface and the a corner of the bottom wall having a bottom wall surface forming a minor angle with respect to each of the second side wall surfaces. As a result, the region that mainly bears the impact load acting on the tray from the vehicle width direction can be a high-strength portion, and the region that is difficult to press can be a low-strength portion. Therefore, the high-strength portion can prevent the tray from being plastically deformed in an early stage and can be made relatively lightweight. At the same time, the low-strength portion allows the tray to be easily manufactured by pressing a steel plate as a base material. Therefore, a robust and lightweight tray can be provided.
Embodiments of the present invention will be described below.
[0012]
(embodiment)
FIG. 1 is an explanatory diagram of the tray 20 according to the embodiment. FIG. 2 is a perspective view of the tray 20 according to the embodiment. FIG. 3 is a plan view of the tray 20 according to the embodiment. 4 is a cross-sectional view taken along the arrow A in FIG. 3. FIG. Unless otherwise specified, the direction along the traveling direction of the vehicle (body 1) is referred to as the front-rear direction, the horizontal direction when viewed in the front-rear direction is referred to as the vehicle width direction, and the vehicle width when viewed in the front-rear direction. The direction perpendicular to the direction or the direction of gravity (vertical direction) is called the up-down direction.
[0013]
As shown in FIG. 1, the vehicle body 1 includes a frame 10 that constitutes the skeleton of the vehicle body 1, and a tray 20 (also referred to as a case or container) on which a battery 30 such as a lithium ion battery is placed. The vehicle body 1, such as an electric vehicle, is driven by a battery 30 as a power source.
[0014]
By protecting the battery 30 from a side collision (pole side collision) with a utility pole, etc., it is possible to suppress harm to the occupants due to an explosion of the battery 30 or the like. Therefore, in order to protect the battery 30, the tray 20 is arranged inside the vehicle from the position of the side member structure 100 (also called side sill). The tray 20 is normally arranged between a pair of side member structures 100 provided on the left and right sides of the vehicle body 1 in the vehicle width direction.
[0015]
Specifically, as shown in FIG. 2 , the tray 20 includes a bottom wall 21 and peripheral side walls 22 standing from the outer circumference of the bottom wall 21 .
[0016]
The bottom wall 21 is a polygon with more than a triangle in plan view. For example, the bottom wall 21 is rectangular in plan view, as shown in FIG. The bottom wall 21 has four corners 21C.
Each corner 21C of the bottom wall 21 is arranged adjacent to each corner 22C of the peripheral side wall 22, which will be described later.
The bottom wall 21 has a flat plate shape. The bottom wall 21 is made of steel, for example. The bottom wall 21 has an upper surface 21a arranged along a horizontal plane. In-vehicle components such as a battery 30 are appropriately placed on the upper surface 21a. The bottom wall 21 has such rigidity that the battery 30 can be placed and supported on the upper surface 21a. The upper surface 21a is appropriately formed with a reinforcing portion 21R formed along the vehicle width direction in order to increase rigidity against deformation of the bottom wall 21 in the vehicle width direction caused by an impact load directed from the vehicle outer side to the vehicle inner side, such as a side collision. may have Note that the reinforcing portion 21R may be a ridge or groove formed along the vehicle width direction.
[0017]
The peripheral side wall 22 has a polygonal shape corresponding to the polygonal shape of the peripheral edge of the bottom wall 21 . For example, as shown in FIG. 3, if the bottom wall 21 is square, the peripheral side wall 22 is square. Specifically, the peripheral sidewall 22 includes a first sidewall 221 , a second sidewall 222 adjacent to the first sidewall 221 , a third sidewall 223 adjacent to the second sidewall 222 , and a third sidewall 223 adjacent to the third sidewall 223 . 4 side walls 224; And the fourth side wall 224 is adjacent to the first side wall 221 . In this way, the side walls from the first side wall 221 to the fourth side wall 224 are arranged in a closed ring so as to surround the bottom wall 21 from the periphery of the bottom wall 21 . The number of side walls forming the peripheral side wall 22 is not limited to four as in the present embodiment, and may be three or more depending on the polygonal shape of the peripheral edge of the bottom wall 21 .
[0018]
Each side wall of the peripheral side wall 22 has an inner surface facing the center surrounded by the peripheral side wall 22 . That is, as shown in FIG. 2, the first sidewall 221 has a first sidewall inner surface 221a. Similarly, the second side wall 222 has a second side wall inner surface 222a. The third sidewall 223 has a third sidewall inner surface 223a. The fourth sidewall 224 has a fourth sidewall inner surface 224a.
[0019]
As shown in FIG. 4, the peripheral wall 22 includes a peripheral wall web 22W extending upward from the vehicle-outboard end of the bottom wall 21, and a peripheral wall flange 22F. It has a cross section. As a result, the tray 20 including the peripheral side wall 22 can be easily formed from a flat steel plate by press working, and at the same time, it can reasonably ensure rigidity capable of resisting loads such as shear forces and moments. In addition, the cross section of the peripheral side wall 22 may be uniform along the peripheral edge of the bottom wall 21 .
[0020]
As shown in FIGS. 2 and 3, the tray 20 includes a high-strength portion HT having high tensile strength and a low-strength portion LT having a lower tensile strength than the high-strength portion HT. From the viewpoint of weight reduction, the high-strength portion HT preferably has a tensile strength of 980 MPa or more, and more preferably has a tensile strength of 1470 MPa or more. From the viewpoint of ease of processing, the low-strength portion LT has a tensile strength of 270 MPa to 440 MPa. The low-strength portion LT has a tensile strength of, for example, 270 MPa, 440 MPa or 590 MPa. For example, when a steel plate having a tensile strength of 1470 MPa is used as the high strength portion HT, a steel plate having a tensile strength of 270 MPa is used as the low strength portion LT having a tensile strength lower than that of the high strength portion HT.
Here, the low-strength portion LT includes a corner portion 22C at the first side wall inner surface 221a of the first side wall 221 and the second side wall inner surface 222a of the second side wall 222 adjacent to each other forming a minor angle, and a first corner portion 22C at the corner portion 22C. The corner 21C on the upper surface 21a of the bottom wall 21 forms a minor angle with respect to each of the side wall inner surface 221a and the second side wall inner surface 222a. Thus, the low-strength portion LT of the tray 20 is formed by the recessed portion C (the first sidewall inner surface 221a, the second sidewall inner surface 222a, and the upper surface 21a) where the corner portion 22C of the peripheral sidewall 22 and the corner portion 21C of the bottom wall 21 are adjacent to each other. are arranged so that the three faces of are included in the adjacent parts). The minor angle is the angle of the smaller one of the angles sharing two sides with the vertex.
Since the tray 20 has such a structure, the high-strength portion HT can be a region that mainly shares and receives the impact load acting on the tray 20 from the vehicle width direction. At the same time, such recessed portion C that is difficult to press can be made into low-strength portion LT. Therefore, the high-strength portion HT can prevent the tray 20 from being plastically deformed in an early stage and can be made relatively lightweight. At the same time, the low-strength portion LT allows the tray 20 to be easily formed into a box-like three-dimensional shape having the recessed portion C by pressing the steel plate serving as the base material. Therefore, a robust and lightweight tray 20 can be provided.
[0021]
Specifically, as shown in FIGS. 2 and 3, the tray 20 has a high-strength portion HT at the intermediate portion in the front-rear direction.
The high-strength portion HT is formed from the first side wall 221 through the bottom wall 21 to the third side wall 223 facing the first side wall 221 . As a result, the range of the load transmission path when the impact load acts can be set to the high strength portion HT. Therefore, even if the plate thickness of the tray 20 is reduced, the rigidity in the vehicle width direction can be increased, so that the weight can be efficiently reduced.
[0022]
The tray 20 has a low-strength portion LT in a region including recessed portions C having two corner portions 21C arranged at the front and corner portions 22C corresponding to the corner portions 21C. Further, the tray 20 has a low-strength portion LT in a region including recessed portions C having two rear corner portions 21C and corner portions 22C corresponding to the corner portions 21C. In this way, since the region including the depression C having the corners 21C and 22C is the low-strength portion LT, the steel plate serving as the base material can be press-worked. The tray 20 can be easily manufactured by
[0023]
The tray 20 has an inner reinforcing member 24 extending from the first side wall 221 to the third side wall 223 facing the first side wall 221 on the bottom wall 21 . As a result, even if an impact load in the vehicle width direction acts on one of the first side wall 221 and the third side wall 223, part of the impact load is shared by the other of the first side wall 221 and the third side wall 223. can be made In addition, the rigidity and buckling strength of the range of the load transmission path can be increased when an impact load acts in the vehicle width direction. Therefore, the protection performance of the inner side of the tray 20 can be improved.
[0024]
A plurality of inner reinforcing members 24 may be provided. Moreover, the inner reinforcing member 24 may be provided in multiple numbers side by side in the front-rear direction. As a result, when an impact load is applied to the first side wall 221 and the third side wall 223 in the vehicle width direction, the cross section perpendicular to the longitudinal direction of the first side wall 221 and the third side wall 223 is subjected to The maximum bending moment can be reduced, and the displacement of the first side wall 221 and the third side wall 223 in the vehicle width direction can be suppressed. In addition, an impact load in the vehicle width direction applied to one of the first side wall 221 and the third side wall 223 due to a side collision or the like can be distributed to the plurality of inner reinforcing members 24 and transmitted to the third side wall 223 . Therefore, the cross section perpendicular to the longitudinal direction (vehicle width direction) per one inner reinforcing member 24 can be made small, and the size can be made compact. In addition, the inner reinforcing member 24 may be provided singularly.
[0025]
One end of the inner reinforcing member 24 is joined to the first side wall inner surface 221a of the first side wall 221 by welding or the like. The other end of the inner reinforcing member 24 is joined to the third side wall inner surface 223a of the third side wall 223 by welding or the like.
[0026]
The inner reinforcing member 24 preferably overlaps the high-strength portion HT. As a result, the rigidity improvement effect of the inner reinforcing member 24 and the rigidity improvement effect of the high-strength portion HT are combined to effectively increase the rigidity in the range of the load transmission path when an impact load acts in the vehicle width direction. can be done. Therefore, the protection performance of the inner side of the tray 20 can be improved.
[0027]
The first side wall 221 and the third side wall 223 have outer stiffeners 25 extending along the first side wall 221 and the third side wall 223 . Note that the outer stiffener 25 generally includes a first outer stiffener 25A extending along the first side wall 221 and a second outer stiffener 25B extending along the third side wall 223 . As a result, the impact load acting from the vehicle outer side toward the vehicle inner side is dispersed in the longitudinal direction of the outer reinforcing member 25, and then transmitted to the bottom wall 21 via the first side wall 221 or the third side wall 223. , the range of the load transmission path can be widened, and the load received by the tray 20 can be dispersed so as not to be locally concentrated. Therefore, the protection performance of the inner side of the tray 20 can be improved.
[0028]
Specifically, as shown in FIG. 4, the outer reinforcing member 25 (first outer reinforcing member 25A) provides bending rigidity and impact energy performance per unit mass against an impact load acting from the outer side to the inner side of the vehicle. For security, it has a hollow cross-section. In addition, the outer reinforcing member 25 has a plurality of members extending in the front-rear direction, that is, a first member 251, a second member 252, and a third member 253. As shown in FIG. The cross section of the outer reinforcing member 25 has a closed annular shape by connecting the first member 251, the second member 252, and the third member 253 to each other. The first member 251, the second member 252, and the third member 253 are joined together by, for example, welding. The first member 251, the second member 252, and the third member 253 are each, for example, a flat steel plate or a steel plate bent from a flat steel plate. The outer reinforcing member 25 and the peripheral side wall 22 are joined to each other by welding or the like. In addition, the outer reinforcing member 25 is not limited to being formed from three members as in the present embodiment, and may be formed from a single member, may be formed from two members, or may be formed from four or more members. may be formed from a plurality of members of
[0029]
(Production method)
Next, a method for manufacturing the tray 20 will be described.
(1) First, a steel plate serving as the high strength portion HT having a high tensile strength and a steel plate serving as the low strength portion LT having a lower tensile strength than the high strength portion HT are welded together (welding step). Here, for example, a steel plate having a tensile strength of 1470 MPa is used as the high strength portion HT. A steel plate having a tensile strength of 270 MPa is used as the low strength portion LT. In addition, it is preferable that the plate thickness of the steel plate forming the high-strength portion HT and the plate thickness of the steel plate forming the low-strength portion LT be the same.
(2) Next, the low-strength portion LT is formed into the corner portion 22C of the first side wall inner surface 221a of the first side wall 221 and the second side wall inner surface 222a of the second side wall 222 adjacent to each other with a minor angle, and the corner portion 22C. Pressing is performed so as to include a recessed portion C having a corner portion 21C in the upper surface 21a of the bottom wall 21 forming a minor angle with respect to each of the first side wall inner surface 221a and the second side wall inner surface 222a in (forming step). At the same time, the high-strength portion HT is pressed. Work hardening by press working can increase the tensile strength of the high-strength portion HT or low-strength portion LT after press-working, compared to the tensile strength of the high-strength portion HT or low-strength portion LT before press working.
According to this method of manufacturing the tray 20, even if the tray 20 has the high-strength portion HT, the depression portion C, which is difficult to form by pressing, is the low-strength portion LT. , and the peripheral side wall 22 erected from the outer periphery of the bottom wall 21 can be easily manufactured. Therefore, it is possible to provide a method for manufacturing a robust and lightweight tray 20 .
Code explanation
[0030]
1 Body
10 frames
100 side member structure
20 trays
30 battery
21 bottom wall
21a upper surface
21C corner
21R reinforcement part
22 Peripheral side wall
22C corner
22F Peripheral side wall flange
22W peripheral side wall web
24 Inner reinforcing material
25 Outer reinforcing material
25A first outer reinforcing material
25B Second outer reinforcing material
251 First member
252 Second member
253 third member
221 First side wall
221a First side wall inner surface
222 Second side wall
222a Second side wall inner surface
223 Third side wall
223a Third side wall inner surface
224 4th side wall
224a fourth side wall inner surface
C recessed part
HT High strength part
LT Low strength part
The scope of the claims
[Claim 1]
A tray comprising a bottom wall and a peripheral side wall standing from the outer periphery of the bottom wall,
The tray includes a high-strength portion having a high tensile strength and a low-strength portion having a lower tensile strength than the high-strength portion,
The low-strength portion includes a corner portion at a first side wall inner surface of a first side wall and a second side wall inner surface of a second side wall adjacent to each other forming an inferior angle, and the first side wall inner surface and the second side wall at the corner portion. and corners at the top surface of the bottom wall that form minor angles with respect to each of the inner surfaces.
A tray characterized by:
[Claim 2]
The high-strength portion is formed from the first side wall through the bottom wall to a third side wall facing the first side wall
A tray according to claim 1, characterized in that:
[Claim 3]
An inner reinforcing member is provided on the bottom wall, extending from the first side wall to a third side wall facing the first side wall
3. The tray according to claim 1 or 2, characterized in that:
[Claim 4]
The inner reinforcing material overlaps the high-strength portion
4. The tray according to claim 3, characterized in that:
[Claim 5]
The first sidewall and the third sidewall comprise an outer stiffener extending along the first sidewall and the third sidewall
5. The tray according to any one of claims 2 to 4, characterized in that:
[Claim 6]
A method for manufacturing a tray comprising a bottom wall and a peripheral side wall erected from the outer circumference of the bottom wall,
a welding step of welding a high-strength portion having a high tensile strength and a low-strength portion having a lower tensile strength than the high-strength portion;
The low-strength portion is a corner portion of the first side wall inner surface of the first side wall and the second side wall inner surface of the second side wall adjacent to each other forming a minor angle, and the first side wall inner surface and the second side wall at the corner portion. pressing to include recesses having corners at the top surface of the bottom wall forming minor angles with respect to each of the inner surfaces.
A tray manufacturing method characterized by: