Case manufacturing method

Abstract

To provide a case manufacturing method for a case that can cast a case in which an inner surface of a side wall is a vertical surface, without needing a core.SOLUTION: A manufacturing method for a case described in the disclosure manufactures a case 1 which is provided with a bottom part 1a and two side walls 1b and 1c, where the inner surfaces 1g and 1h of the two side walls 1b and 1c are perpendicular to the bottom part 1a. The manufacturing method comprises a first step ST1 and a second step ST2. In the first step ST1, the case 1 is casted using a die-casting method. In the die-casting method, a die M10 comprising an upper die M1 and a lower die M2 is used. The lower die M2 has a cavity surface formed so that the bottom part 1a inclines with respect to a horizontal surface XY1 and the upper die M1 has a cavity surface formed so that a draft providing part 1i is provided only on either of the two side walls 1b and 1c. In the second step ST2, the draft providing part 1i is cut to be removed only from the either of the two side walls 1b and 1c after the first step ST1.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a case.

Background Art

[0002] In the manufacturing method disclosed in Patent Document 1, a battery case is cast. The battery case has a bottom wall portion and a standing wall portion standing from the bottom wall portion, and a plurality of cells are accommodated inside a box-shaped container that is open upward. When casting, a first core is placed at a position corresponding to the inside of the standing wall portion of the battery case in the mold and casting is performed. The first core has an outer surface that is perpendicular to the bottom wall portion and an inner surface that has a draft gradient inclined with respect to the bottom wall portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventors of the present application have discovered the following problems. In such a method for manufacturing a case, since a core is required, there is a risk that the manufacturing cost will increase. There is a need for a method for manufacturing a case that can cast a case in which the inner surface of the side wall is perpendicular to the bottom surface without requiring a core.

[0005] The present disclosure has been made in view of the above-described problems, and provides a method for manufacturing a case that can cast a case in which the inner surface of the side wall is perpendicular to the bottom surface without requiring a core.

Means for Solving the Problems

[0006] The method for manufacturing a case according to the present disclosure is A method for manufacturing a case including a bottom and two side walls, wherein the inner surfaces of the two side walls are perpendicular to the bottom, A first step of casting the case using a die-casting method, In the die-casting method, a mold having an upper mold and a lower mold is used, The lower mold has a cavity surface such that the bottom is inclined with respect to the horizontal plane, A first step in which the upper mold has a cavity surface so as to provide a draft allowance portion only on one of the two side walls, After the first step, a second step of machining the draft allowance portion to remove it only from one of the two side walls, After the first step and before the second step, only the other of the two side walls is perpendicular to the bottom.

Advantages of the Invention

[0007] According to the present disclosure, a case in which the inner surface of the side wall is perpendicular to the bottom surface can be cast without requiring a core.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0009] Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings are simplified as appropriate.

[0010] <Embodiment 1> Embodiment 1 will be described with reference to FIGS. 1 to 3.

[0011] Of course, the right-handed XYZ coordinates shown in FIG. 1 and other drawings are for convenience in explaining the positional relationship of the components. Usually, the positive Z-axis direction is vertically upward, the XY plane is a horizontal plane, and is common among the drawings.

[0012] As shown in FIG. 1, the case 1 is a box-shaped body with an open top. Specifically, the case 1 includes a bottom 1a, side walls 1b, 1c, 1d, 1f, and a central wall 1e. The case 1 is a die-cast casting. The case 1 is made of a metal material that can be used for die-casting. Such a metal material is, for example, an aluminum alloy or the like. The case 1 can be used as a battery case.

[0013] The bottom 1a is a substantially rectangular plate along a horizontal plane (here, the XY1 plane). The bottom 1a has an upper bottom surface 1aa and a lower bottom surface 1ab shown in FIG. 2. The upper bottom surface 1aa faces upward (here, the positive Z-axis direction). The lower bottom surface 1ab faces downward (here, the negative Z-axis direction).

[0014] The side walls 1b, 1c, 1d, 1f each rise vertically (here, the positive Z-axis direction) from the outer edge of the bottom 1a and extend along the outer edge of the bottom 1a. The side wall 1b and the side wall 1c are opposed to each other. Specifically, the side wall 1b has an inner surface 1g facing the inside of the case 1. The side wall 1c has an inner surface 1h facing the inside of the case 1. The inner surface 1g and the inner surface 1h are opposed to each other. The inner surface 1g of the side wall 1b is perpendicular to the upper bottom surface 1aa of the bottom 1a. The inner surface 1h of the side wall 1c is perpendicular to the upper bottom surface 1aa of the bottom 1a. The side wall 1d and the side wall 1f are opposed to each other. One end of the side wall 1b and one end of the side wall 1d are mechanically connected. One end of the side wall 1b and one end of the side wall 1f are mechanically connected. One end of the side wall 1c and the other end of the side wall 1d are mechanically connected. The other end of the side wall 1c and the other end of the side wall 1f are mechanically connected. The side walls 1b, 1c, 1d, 1f are arranged along a substantially square shape at the bottom 1a.

[0015] The central wall 1e rises vertically from the bottom 1a between the side walls 1d and 1f. The central wall 1e mechanically connects the vicinity of the center of the side wall 1b and the vicinity of the center of the side wall 1c.

[0016] The central wall 1e partitions the space surrounded by the side walls 1b, 1c, 1d, and 1f. The bottom 1a, the central wall 1e, and the side walls 1b, 1c, 1d form an accommodation space SP1. The bottom 1a, the central wall 1e, and the side walls 1b, 1c, 1f form an accommodation space SP2. The resin frame 2 and the cell 3 are accommodated in the accommodation spaces SP1 and SP2. In the accommodation spaces SP1 and SP2, the resin frame 2 and the cell 3 are alternately arranged in the stacking direction (here, the X-axis direction), and a laminate of the resin frame 2 and the cell 3 is formed. The laminate of the resin frame 2 and the cell 3 may be compressed in the stacking direction and accommodated in the accommodation spaces SP1 and SP2. At one end in the stacking direction of the laminate of the resin frame 2 and the cell 3, a resin frame 2g is arranged. At the other end in the stacking direction of the laminate of the resin frame 2 and the cell 3, a resin frame 2h is arranged. The resin frame 2g contacts the inner surface 1g and is pressed by the inner surface 1g. The resin frame 2h contacts the inner surface 1h and is pressed by the inner surface 1h. The inner surfaces 1g and 1h function as restraining surfaces for restraining the laminate of the resin frame 2 and the cell 3. The laminate of the resin frame 2 and the cell 3 functions as a battery body and may be able to supply power to the outside.

[0017] <Manufacturing Method> Next, with reference to FIGS. 1 to 3, a manufacturing method of the case 1 will be described. Note that FIG. 2 schematically shows a cross section taken along the cutting line II-II shown in FIG. 1 for each step of the manufacturing method of the case 1. FIG. 3 is a cross-sectional view of the mold used in the manufacturing method of the case shown in FIG. 2. In FIG. 3, for ease of viewing, the illustration of hatching is omitted.

[0018] The die-cast casting 10 is cast using a die-cast casting method (the first step ST1). In the die-cast casting method, the mold M10 shown in FIG. 3 can be used.

[0019] The mold M10 includes an upper mold M1 and a lower mold M2. At least one of the upper mold M1 and the lower mold M2 may be attached to a die-casting machine (not shown) so as to be movable in the vertical direction. The upper mold M1 and the lower mold M2 are clamped. Then, a cavity CV is formed between the upper mold M1 and the lower mold M2. The cavity CV is a space having substantially the same shape as the die-cast casting 10. By injecting the molten metal into the cavity CV of the mold M10 and pressing it, the die-cast casting 10 can be formed in the cavity CV. The cavity surface M2a of the lower mold M2 is inclined from the horizontal plane XY1. Specifically, the angle α3 formed by the intersection of the cavity surface M2a of the lower mold M2 and the horizontal plane XY1 is a predetermined value. This predetermined value is greater than 0 (zero) degrees. The PL plane may be arranged at a position corresponding to the vicinity of the top of the side wall 1c shown in FIG. 2.

[0020] The surface shape of the cavity surface M2a is transferred, and the bottom 1a of the die-cast casting 10 is formed. As shown in FIG. 2, the bottom 1a of the die-cast casting 10 is inclined from the horizontal plane XY1. Specifically, the angle α1 formed by the intersection of the lower bottom surface 1ab of the bottom 1a and the horizontal plane XY1 is a predetermined value. This predetermined value is greater than 0 (zero) degrees. The die-cast casting 10 is provided with a draft allowance portion 1i. The draft allowance portion 1i is provided on the inner surface 1g of the side wall 1b. The surface 1ig of the draft allowance portion 1i imparts a draft to the side wall 1b. The side wall 1b and the draft allowance portion 1i do not correspond to an undercut shape. For example, the surface 1ig may be inclined such that the cross-sectional area of the upper mold M1 decreases toward the lower mold M2 side.

[0021] Separate the upper mold M1 from the lower mold M2, and remove the die-cast casting 10 from the mold M10. As described above, the surface 1ig of the draft gradient imparting portion 1i imparts a draft gradient to the side wall 1b. Therefore, the upper mold M1 can be smoothly separated from the lower mold M2 without being caught by the inner surface 1g of the side wall 1b and the draft gradient imparting portion 1i. Place the die-cast casting 10 so that the lower bottom surface 1ab of the bottom portion 1a of the die-cast casting 10 is along the horizontal plane XY2. The angle α2 formed by the intersection of the lower bottom surface 1ab of the bottom portion 1a and the horizontal plane XY2 is preferably 0 (zero). The surface 1ig of the draft gradient imparting portion 1i is inclined from the vertical direction Z1 extending from the bottom portion 1a toward the side wall 1b. The angle formed by the intersection of the surface 1ig and the upper bottom surface 1aa of the bottom portion 1a is an obtuse angle.

[0022] Subsequently, machine the draft gradient imparting portion 1i of the die-cast casting 10 to form the inner surface 1g (second step ST2). The inner surface 1g is perpendicular to the bottom portion 1a. In other words, the angle formed by the intersection of the inner surface 1g and the upper bottom surface 1aa of the bottom portion 1a is a right angle. Case 1 can be manufactured.

[0023] As described above, the die-cast casting 10 can be cast without the need for a core. Also, as described above, the inner surfaces 1g and 1h of the side wall 1c of the die-cast casting 10 are perpendicular to the bottom portion 1a and are vertical surfaces. Therefore, a die-cast casting 10 having a vertical inner surface 1h of the side wall 1c can be cast.

[0024] Note that the present invention is not limited to the above-described embodiments, and can be appropriately modified without departing from the gist. Also, the present invention may be implemented by appropriately combining the above-described embodiments and examples thereof. For example, in the first step ST1 described above, the upper mold M1 was separated from the lower mold M2, but the lower mold M2 may be separated from the upper mold M1, or the upper mold M1 and the lower mold M2 may be separated from each other.

Explanation of Reference Numerals

[0025] 1 Case 1a Bottom portion 1aa Upper bottom surface 1ab Lower bottom surface Side walls 1b, 1c, 1d, 1f Central wall 1e Inner surfaces 1g, 1h Draft gradient imparting portion 1i Surface 1ig Resin frames 2, 2g, 2h Cell 3 Die casting 10 CV cavity Mold M10 Upper mold M1 Lower mold M2 Cavity surface M2a Accommodation spaces SP1, SP2 Horizontal planes XY1, XY2

Claims

【Claim 1】 A method for manufacturing a case comprising a bottom and two side walls, wherein the inner surfaces of the two side walls are perpendicular to the bottom, A first step of casting the case using a die-casting method, In the die-casting method, a mold having an upper mold and a lower mold is used, The lower mold has a cavity surface such that the bottom is inclined with respect to the horizontal plane, A first step in which the upper mold has a cavity surface so as to provide a draft allowance portion only on one of the two side walls, After the first step, a second step of cutting the draft allowance portion and removing it only from one of the two side walls, After the first step and before the second step, only the other of the two side walls is perpendicular to the bottom, A method for manufacturing a case.

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