Method for manufacturing rectangular tubes, apparatus for manufacturing rectangular tubes
The method addresses shape accuracy and material breakage issues in square tube manufacturing by using a plate and mold deformation process, improving the rectangular cylinder's shape and reducing the need for cutting and material fracture.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2024-11-15
- Publication Date
- 2026-05-27
AI Technical Summary
Existing methods for manufacturing square tubes by applying tensile force to cylindrical bodies result in concave stripes, curvature, and material breakage, making it difficult to achieve accurate shapes and increasing the risk of material fracture.
A method involving the use of a plate inside a cylindrical body to be molded, followed by deformation using a receiving mold with a wide opening and sloping surface, forming side portions by sandwiching the cylindrical body between a plate and mold, reducing deformation and improving shape accuracy.
Reduces the need for cutting curved parts and minimizes material fracture risk while enhancing the shape accuracy of the rectangular cylinder.
Smart Images
Figure 2026087231000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a method for manufacturing a square tube and a manufacturing apparatus for a square tube.
Background Art
[0002] Patent Document 1 discloses a method for manufacturing a square tube for a square battery, in which a cylindrical body is plastically deformed by applying a tensile force in a direction orthogonal to the tube axis to form a square tube.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] When a cylindrical body is plastically deformed by applying a tensile force in a direction orthogonal to the tube axis to form a square tube, due to the tensile force, as shown in FIG. 9, concave stripes are formed such that the central portion is recessed at both ends of the first flat portion and the second flat portion. Therefore, it is necessary to cut this to make it straight. In addition, if it is only expanded by the tensile force from the inside of the tube, curvature often remains in the first side surface portion and the second side surface portion, or a large R remains at the corner between the side surface portion and the flat surface portion, and it is often impossible to obtain an accurate shape. If the tensile force is increased in an attempt to obtain an accurate shape, there is a risk of material breakage.
[0005] Therefore, an object of the present disclosure is to provide a method for manufacturing a square tube that suppresses deformation at both ends in the tube axis direction of the square tube, improves the shape accuracy of a square shape in a cross section orthogonal to the tube axis, and is also less likely to cause material breakage.
Means for Solving the Problems
[0006] This application discloses a method for manufacturing a rectangular cylinder having a first side portion and a second side portion that face each other, comprising the steps of: placing a plate-shaped plate inside a cylindrical body to be molded; inserting the cylindrical body containing the plate inside into a groove of a receiving mold to deform the cylindrical body and form the first side portion, thereby producing a cylindrical intermediate body; placing a plate-shaped plate inside the intermediate body; and inserting the intermediate body containing the plate inside into a groove of a receiving mold to deform the intermediate body and form the second side portion.
[0007] The receiving mold may have a wide opening on the groove insertion side and a sloping surface that narrows towards the bottom of the groove.
[0008] The width of the plate placed inside the intermediate may be greater than the width of the plate placed inside the cylindrical body.
[0009] This application discloses a cylindrical body manufacturing apparatus comprising a plate positioned inside a cylindrical body to be molded, and a receiving mold having a groove into which the cylindrical body in which the plate is positioned is inserted, wherein the receiving mold has a wide opening on the insertion side of the groove and an inclined surface that narrows towards the bottom of the groove. [Effects of the Invention]
[0010] According to this disclosure, since the rectangular cylinder is formed by press working, deformation as shown in Figure 9 is less likely to occur, and the need to cut curved parts to create a straight shape can be reduced. In addition, since the first and second side portions are formed by sandwiching them between a plate and a mold, the shape accuracy can be improved. The risk of material fracture during this forming process can also be reduced. [Brief explanation of the drawing]
[0011] [Figure 1] Figure 1 illustrates the shapes of the cylindrical body 11 before molding and the rectangular cylinder 12 after molding, which are the objects to be molded. [Figure 2] Figure 2 is a diagram illustrating the molding plate 20. [Figure 3]Figure 3 is a diagram illustrating the receiving mold 30. [Figure 4] Figure 4 illustrates the first molding plate insertion process. [Figure 5] Figure 5 illustrates the first side molding process. [Figure 6] Figure 6 illustrates the second molding plate insertion process. [Figure 7] Figure 7 illustrates the second side molding process. [Figure 8] Figure 8 illustrates the pre-molding process. [Figure 9] Figure 9 illustrates the possible configuration of a recess that may occur at the axial end of the cylindrical portion of the flat section. [Modes for carrying out the invention]
[0012] 1.Molded object As shown in Figure 1, the object to be molded is a seamless cylindrical tube member (sometimes referred to as "pre-molding cylinder 11") as shown in the upper part of Figure 1 before molding, and becomes a rectangular cylinder (sometimes referred to as "post-molding rectangular cylinder 12") as shown in the lower part of Figure 1 after molding. The pre-molding cylindrical body 11 is not limited to being a cylinder as shown in Figure 1, and may have other shapes. However, from the viewpoint of improving the uniformity of the wall thickness of the post-molding rectangular cylinder 12, it is preferable that the pre-molding cylindrical body 11 is cylindrical. As shown in Figure 1, the molded rectangular cylinder 12 is a cylindrical body with a rectangular cross-section. However, the difference between the long side and the short side is large and the rectangle is flattened. Here, the surface formed by the short side is called the side surface, with one side being called the first side surface 13 and the other the second side surface 14. The surface formed by the long side is called the flat surface, with one side being called the first flat surface 15 and the other the second flat surface 16.
[0013] The material, properties, dimensions, etc. of the pre-formed cylindrical body 11 to be formed are not particularly limited, and examples of the material include aluminum, aluminum alloy, stainless steel, copper, iron, titanium, nickel, etc. From the perspective of material strength, the tensile strength is 70 MPa to 300 MPa, the yield strength is 30 MPa to 200 MPa, and the elongation is 2% to 30%. The plate thickness can also be 0.1 mm to 2.0 mm.
[0014] 2. Form of the manufacturing apparatus The form of the manufacturing apparatus used for the manufacturing method of the present disclosure is not particularly limited, and for example, the following can be mentioned. Figures 2 and 3 show diagrams for explanation. The manufacturing apparatus according to this exemplary form includes a forming plate 20 (Figure 2) and a receiving-side mold 30 (Figure 3).
[0015] 2.1. Forming plate As shown in Figure 2, the forming plate 20 is a plate-shaped member in the form of a rectangular parallelepiped. Since the forming plate 20 is inserted inside the pre-formed cylindrical body 11 and the intermediate body 11 to be described later, the inner surface of the formed square cylinder 12 is also formed. Therefore, the thickness T of the forming plate 20 is generally the same as the size between the inner surfaces of the opposing first flat surface portion 15 and second flat surface portion 16 of the formed square cylinder 12.
[0016] The width W of the forming plate 20 is configured to be insertable inside the pre-formed cylindrical body 11 and the intermediate body 11 to be described later. When manufacturing the square cylinder 12 as described later, there are a process of forming the first side surface portion 13 and a process of forming the second side surface portion 14, and the forming plate 20 is used in both cases. However, the same width W or different widths W may be used in the process of forming the first side surface portion 13 and the process of forming the second side surface portion 14. Specific examples of the size of the width W will be described later.
[0017] The length L of the forming plate 20 is configured to be longer than the length in the cylinder axis direction of the pre-formed cylindrical body 11 and the intermediate body 11 to be described later.
[0018] 2.2. Receiving-side mold The receiving mold 30 is a component having a groove 31, as shown in Figure 3, and is a component that forms the outer shape of the rectangular cylinder 12 after molding. Therefore, the width W of the groove 31 M This is approximately the same as the size between the outer surfaces of the first flat portion 15 and the second flat portion 16 of the molded rectangular cylinder 12. The depth D of the groove 31, excluding the guide portion 31a, is formed to be at least larger than the distance between the two side portions of the molded rectangular cylinder 12. The bottom portion 31b of the groove 31 is flat so as to form the first side portion 13 and the second side portion 14 of the molded rectangular cylinder 12. The side wall surface that forms from the groove opening (insertion port) to the bottom portion 31b of the groove 31 is also flat so as to form the first flat portion 15 and the second flat portion 16 of the molded rectangular cylinder 12. This side wall surface contributes to the surface properties of the molded rectangular cylinder 12, and for smooth molding, it is preferable that the surface roughness of the side wall surface of the groove 31 is small, and it may be coated. Length of groove 31 (L M ) is configured to be longer than the length of the cylindrical body 11 before molding.
[0019] Furthermore, in this embodiment, the receiving mold 30 has a Y-shaped guide portion 31a that has a tapered surface from the opening end (insertion port) in the depth direction (direction D) of the groove 31, so that the groove width narrows towards the bottom. This makes the insertion of the pre-molded cylindrical body 11 into the groove 31 smoother. The angle of the Y-shape is not particularly limited, but can be between 30 and 120 degrees.
[0020] 3. Manufacturing method for rectangular tubes 3.1.First form Next, a method for manufacturing a rectangular cylinder of the first form, S10 (sometimes referred to as "manufacturing method S10"), will be described. Manufacturing method S10 includes a first molding plate insertion step S11, a first side surface molding step S12, a second molding plate insertion step S13, and a second side surface molding step S14.
[0021] 3.1.1. First molding plate insertion process In the first molding plate insertion step S11, as shown in Figure 4, the molding plate 20 is inserted into the inside of the pre-molding cylindrical body 11, which is a cylindrical seamless tube. This insertion is performed so that the width direction of the molding plate 20 is in the diameter direction of the pre-molding cylindrical body 11. The width W of the molding plate 20 at this time is set to a size that allows the molding plate 20 to be inserted along the inner diameter of the pre-molding cylindrical body 11 when the pre-molding cylindrical body 11 is cylindrical. For example, the width W can be set such that the two lower edges 21 of the four edges 21 formed by the corners of a rectangle (width (W) and thickness (T)) touch the inner surface of the pre-molding cylindrical body 11, while the gap between the two upper edges 21 and the inner surface of the pre-molding cylindrical body 11 is in the range of 0.05 mm to 1 mm.
[0022] 3.1.2. First side part forming process In the first side portion forming step S12, the pre-molding cylindrical body 11, on which the molding plate 20 is placed, is inserted into the groove 31 of the receiving mold 30 to form the first side portion 13. Specifically, as shown in Figures 5(a) and 5(b), the molding plate 20, which is placed inside the pre-molding cylindrical body 11, is inserted into the groove 31 of the receiving mold 30 such that the width direction of the plate 20 is in the depth direction of the groove 31 of the receiving mold 30. As a result, the pre-molding cylindrical body 11 is deformed by being sandwiched between the side wall surface of the groove 31 and the molding plate 21, and the first flat portion 15 and the second flat portion 16 are formed sequentially.
[0023] More specifically, in the intermediate stage shown in Figure 5(a), the deformation causes a portion of the pre-molding cylindrical body 11 that cannot make close contact with the molding plate 20 to form a gap 11a on the insertion side of the groove 31 (guide portion 31a side). Since this gap 11a is slightly larger than the width of the groove 31, it is necessary to further press the molding plate 20 in the depth direction of the groove 31 (direction of arrow A in Figure 5(a)). This generates a force acting in the opposite direction to this pressing force (arrow B in Figure 5(b)). At this time, a small gap 11b is also created on the bottom 31b side of the groove 31 in the pre-molded cylindrical body 11, preventing the pre-molded cylindrical body 11 from making close contact with the molding plate 20.
[0024] From the state shown in Figure 5(a), if the molding plate 20 is inserted into the groove 31 in the direction of arrow A against the force of arrow B, the gap 11b is deformed by being sandwiched between the bottom 31b of the groove 31 and the molding plate 20, as shown in Figure 5(b), and the first side portion 13 is formed. In this process, the first side portion 13 can be formed by pressing.
[0025] Subsequently, the molding plate 20 and the pre-molding cylinder 11 are removed from the groove 31, and then the molding plate 20 is removed from the pre-molding cylinder 11. The pre-molding cylinder 11 at the end of this process is referred to as the intermediate body 11.
[0026] 3.1.3. Second Molding Plate Insertion Process In the second molding plate insertion step S13, the molding plate 20 is inserted inside the intermediate body 11 as shown in Figure 6. At this time, one end of the molding plate 20 in the width direction is in contact with the first side surface portion 13 formed in the previous step, and the other end of the molding plate 20 in the width direction is positioned towards the gap 11a.
[0027] The molding plate 20 in this process may be the same as the molding plate 20 inserted in the first molding plate insertion step S11 described above, or it may be different. A different molding plate 20 may have a width W greater than that of the molding plate 20 inserted in the first molding plate insertion step S11. In the first molding plate insertion step S11 described above, the molding plate 20 is placed inside the pre-molding cylindrical body 11, so the width of the molding plate 20 that fits there cannot exceed the inner diameter of the pre-molding cylindrical body 11. In contrast, the intermediate body 11 has been deformed in the previous step, so a molding plate 20 with a larger width can be inserted. In order to improve the accuracy of molding, it is preferable to fill as much of the inside area of the intermediate body 11 as possible with the molding plate 20, and from this viewpoint, it is preferable to use a molding plate 20 with a larger width than that used in the previous step in this step.
[0028] 3.1.4.Second side part forming process In the second side portion forming step S14, as shown in Figure 7, an intermediate body 11 with the molding plate 20 placed in it is inserted into the groove 31 of the receiving mold 30. As a result, the intermediate body 11 is deformed by being sandwiched between the side wall surface of the groove 31 and the molding plate 20, and the first flat portion 15 and the second flat portion 16 are formed.
[0029] In the intermediate stage shown in Figure 7(a), a small gap 11a is formed on the bottom 31b side of the groove 31 within the intermediate body 11, preventing the intermediate body 11 from making close contact with the molding plate 20. In this process, the insertion side of the groove 31, as shown in Figure 6(a), is already the first side surface 13, and no gap like the gap 11a is formed. By further inserting the molding plate 20 inside the intermediate body 11 into the groove from this state, the gap 11a in the intermediate body 11 is squeezed and compressed between the bottom 31b of the groove 31 and the molding plate 20, forming the second side surface 14.
[0030] Subsequently, the molding plate 20 and the molded rectangular cylinder 12 are removed from the groove 31, and then the molding plate 20 is removed from the molded rectangular cylinder 12.
[0031] 3.1.5. Effects, etc. According to this embodiment, since the post-molding rectangular cylinder is formed by press working, deformation as shown in Figure 9 is less likely to occur, and there is no need to cut it to create a straight shape. In addition, the first and second side portions are formed by sandwiching them between a plate and a mold, which improves shape accuracy. The risk of material fracture during this molding process can also be reduced.
[0032] 3.2.Second form Next, a method for manufacturing a second form of rectangular cylinder, S20 (sometimes referred to as "manufacturing method S20"), will be described. Manufacturing method S20 includes a first molding plate insertion step S21, a first side molding step S22, a second molding plate insertion step S23, a pre-molding step S24, and a second side molding step S25.
[0033] 3.2.1. First molding plate insertion process The first molding plate insertion step S21 can be considered the same as the first molding plate insertion step S11 described in the manufacturing method S10.
[0034] 3.2.2. First side part forming process The first side molding step S22 can be considered the same as the first side molding step S12 described in the manufacturing method S10.
[0035] 3.2.3. Second Molding Plate Insertion Process The second molding plate insertion step S23 can be considered the same as the second molding plate insertion step 13 described in the manufacturing method S10. However, the molding plate 20 used here has a larger width W than the molding plate 20 used in the first molding plate insertion step.
[0036] 3.2.4. Pre-forming process In the pre-forming process S24, the combination of the intermediate body 11 and the molding plate 20 (see Figure 6) produced in the second molding plate insertion process S23 is inserted into the groove 31 of the receiving mold 30 as shown in Figure 8. That is, in the pre-forming process S24, as shown in Figure 8, the combination of the intermediate body 11 and the molding plate 20 produced in the second molding plate insertion process S23 is inserted into the groove 31 with the first side portion 13 facing the bottom portion 31b of the groove 31 (with the gap 11a facing the insertion portion side of the groove 31). In the first side molding process S22, a molding plate 20 with a relatively small width W is used, resulting in a large gap 11a as shown in Figure 5(b), and the surface of the gap 11a is prone to unevenness, as also shown in Figure 5(b). In contrast, by using a molding plate 20 with a larger width W in the pre-molding process S24 and molding again, the unevenness of the gap 11a can be reduced and the product can be prepared for the next process, thereby improving the shape accuracy of the molded rectangular cylinder 12. Then the intermediate 11 and the molding plate 20 are removed from the groove 31.
[0037] 3.2.5.Second side part forming process In the second side molding step S25, the intermediate body 11 and the molding plate 20 are molded in the same manner as in the second side molding step S14 described in the manufacturing method S10 to form the second side 14.
[0038] 3.2.6. Effects, etc. According to manufacturing method S20, in addition to the effects of manufacturing method S10 described above, the shape accuracy of the post-molding rectangular cylinder 12 can be further improved by the pre-molding process S24. [Explanation of Symbols]
[0039] 11...Unmolded cylindrical body, 12...Post-molded rectangular cylinder (rectangular cylinder), 20...Molding plate, 30...Receiving mold
Claims
1. A method for manufacturing a rectangular cylinder having a first side portion and a second side portion that face each other, The process involves placing a plate-shaped plate inside the cylindrical body to be molded, A step of inserting the cylindrical body containing the plate inside into a groove of a receiving mold, deforming the cylindrical body to form a first side portion, and manufacturing a cylindrical intermediate body, The process involves placing a plate-shaped plate inside the intermediate, The process includes inserting the intermediate body containing the plate on the inside into the groove of the receiving mold and deforming the intermediate body to form the second side portion, A method for manufacturing rectangular tubes.
2. The method for manufacturing a rectangular cylinder according to claim 1, wherein the receiving mold has a wide opening on the insertion side of the groove and an inclined surface that narrows towards the bottom of the groove.
3. The method for manufacturing a rectangular cylinder according to claim 1 or 2, wherein the width of the plate disposed inside the intermediate is greater than that of the plate disposed inside the cylindrical body.
4. A plate placed inside the cylindrical body to be molded, The receiving mold has a groove into which the cylindrical body, which is positioned inside the plate, is inserted. The receiving mold has a wide opening on the insertion side of the groove and an inclined surface that narrows towards the bottom of the groove. A manufacturing apparatus for cylindrical bodies.