Incremental forming apparatus and incremental forming method

Abstract

To provide a sequential molding apparatus that can efficiently manufacture various cross-section hat-shaped molded articles even in small quantities.SOLUTION: The present invention is an apparatus (D) for sequentially molding a plate material in the cross-section hat shape in which the center part protrudes from the left and right side parts. The apparatus comprises at least: a front tool group (1) and a rear tool group (2) arranged in front and back along the molding direction of the plate material; and a front actuator group (3) and a rear actuator group (4) that actuate the front tool group and the rear tool group respectively. The front tool group includes a pair of front-left tools (11) provided so as to be opposed vertically, a front-right tool (12), and a front-middle tool (13). The rear tool group includes a pair of rear-left tools (21) provided so as to be opposed vertically, a rear-right tool (22) and a rear-middle tool (23). The left-right widths of the front-middle tool and the rear-middle tool may be changed.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] The present invention relates to an apparatus for incrementally forming a plate material into a hat-shaped cross section. [Background technology]

[0002] Molded products with a hat-shaped cross section (hat-shaped with a brim) where the center section protrudes from the sides, or with a grooved (U-shaped) cross section, are used for structural components that require high mechanical properties (rigidity, strength, etc.) Generally, such molded products are mass-produced by press-molding flat plates (raw material) in large molds.

[0003] However, when producing a large number of molded products with different shapes in small quantities, if a mold is prepared for each molded product and press-molded, the manufacturing cost of each molded product increases significantly. Therefore, various molding methods that can accommodate the small-lot production of a wide variety of molded products without using large molds have been proposed, and for example, there are related descriptions in the following patent documents. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 11-77169 [Patent Document 2] WO2015 / 56351 [Patent Document 3] Patent Publication No. 2019-111537 [Non-patent literature]

[0005] [Non-Patent Document 1] 36th IDDRG Conference - Materials Modelling and Testing for Sheet Metal Forming, Journal of Physics:Conf. Series 896 (2017) 012038 Summary of the Invention [Problem to be solved by the invention]

[0006] Both documents propose a method using roll forming. However, such a method requires a long and large forming apparatus and does not allow for a large degree of freedom in the shape of the resulting formed product. Therefore, it is difficult to achieve a significant reduction in the manufacturing cost of formed products that are produced in small quantities and with a wide variety of products.

[0007] The present invention has been made in view of the above circumstances, and has an object to provide an incremental forming apparatus and the like that can produce various hat-shaped formed products using a method different from conventional methods. [Means for solving the problem]

[0008] As a result of intensive research into solving this problem, the inventor came up with the idea of ​​producing various hat-shaped molded products by repeatedly using multiple tools (molds) smaller than the molded product to gradually mold the sheet material.The inventor further developed this idea and completed the present invention, which will be described below.

[0009] 《Sequential molding device》 (1) The present invention is an apparatus for successively forming a plate material into a hat-shaped cross section with the central portion protruding from the left and right sides, and the apparatus comprises at least a front tool group and a rear tool group arranged front to back along the forming direction of the plate material, and a front actuator group and a rear actuator group for operating the front tool group and the rear tool group, respectively. The front tool group comprises a front left tool arranged opposite to each other in the vertical direction and clamping the left side of the plate material, a front right tool arranged opposite to each other in the vertical direction and clamping the right side of the plate material, and a front middle tool arranged opposite to each other in the vertical direction and forming or clamping the central portion of the plate material. The rear tool group comprises a front left tool arranged opposite to each other in the vertical direction and clamping the right side of the plate material. The incremental forming apparatus includes a rear-left tool that clamps the left side of a plate material, a rear-right tool that is arranged opposite to the top and bottom and clamps the right side of the plate material, and a rear-middle tool that is arranged opposite to the top and bottom and forms or clamps the center of the plate material, and the front actuator group includes a front-left actuator that operates the front-left tool, a front-right actuator that operates the front-right tool, and a front-middle actuator that operates the front-middle tool, and the rear actuator group includes a rear-left actuator that operates the rear-left tool, a rear-right actuator that operates the rear-right tool, and a rear-middle actuator that operates the rear-middle tool.

[0010] (2) According to the incremental forming apparatus (also simply referred to as the "apparatus") of the present invention, various desired hat-shaped molded products can be produced at low cost, even in small quantities, by sequentially forming sheet material using the tools constituting the front tool group and the rear tool group in cooperation. Furthermore, by reducing the processing volume (molding volume) per operation and the molding load, the apparatus can be made smaller and more compact. Furthermore, by using small tools with excellent versatility (commonality) that can accommodate various hat shapes, the cost of the tools can be reduced, and ultimately the production cost of each molded product can be reduced. In this way, using the apparatus of the present invention makes it possible to efficiently produce (produce) desired hat-shaped molded products at low cost, even in small quantities.

[0011] 《Sequential molding method》 The present invention can also be understood as an incremental forming method. For example, the present invention may be a method for incrementally forming a sheet material into a hat-shaped cross section using the above-described device. More specifically, for example, the following steps may be repeated in sequence: a transfer step in which the sheet material in an unclamped state is transferred to a predetermined position; a gripping step in which the sheet material after the transfer step is gripped by the rear tool group; and a shaping step in which the sheet material gripped by the rear tool group is shaped by the front tool group. The gripped state is a state in which the sheet material is clamped by all or part of the tool group and is constrained in the feed direction or the shaping direction (usually the front-to-rear direction). The non-gripped state is a state in which the sheet material is not clamped by the tool group and is movable in the feed direction or the shaping direction.

[0012] "others" (1) In this specification, the terms "upper and lower," "front and rear," and "left and right" are used for convenience to clarify the positional relationship. "Up" (above, upper side, etc.) and "down" (below, lower side, etc.) do not necessarily have to follow the vertical direction. Unless there is a problem, the vertical direction can usually be considered the up-down direction.

[0013] Unless otherwise specified, "front" (forward, front side, etc.) refers to the forward side of the molding direction, and "rear" (rear, rear side, etc.) refers to the opposite side. The molding direction is the direction in which incremental molding progresses. The molding direction may be linear, curved (including arc-shaped), or a combination of these.

[0014] "Left" (left side, left side, etc.) and "right" (right side, right side, etc.) are based on the forming direction (the direction when viewed from the back to the front). When the sheet metal is formed sequentially while being reciprocated, the direction of travel (forming direction) is reversed on the outward and return journeys, so "front / back" and "left / right" are also reversed on the outward and return journeys.

[0015] In this specification, "relative" means that at least one of the plate material and the group of tools needs to move. For example, if the plate material is moved backward relative to the group of tools, incremental forming will proceed forward (in the forming direction).

[0016] The "center" and "side" indicate the relative positions of the sheet material. The widths of the "right side" and "left side" may be the same or different. The "center" only needs to be midway between the "right side" and "left side", and does not have to be symmetrical about the center line of the sheet material. In the case of a molded product with a hat-shaped cross section, the center is the top and the sides are the flanges. The flanges formed on both sides of the center are also referred to as the left flange and right flange, or the outer (side) flange and inner (side) flange, depending on the shape of the molded product.

[0017] (2) Unless otherwise specified, "x to y" in this specification includes a lower limit value x and an upper limit value y. Any numerical value included in the various numerical values ​​or numerical ranges described in this specification may be used as a new lower limit or upper limit value to create a new range such as "a to b." Also, "x to y mm" in this specification means x mm to y mm. The same applies to other unit systems. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a plan view schematically illustrating an overview of an incremental forming device (one example). [Figure 2A] FIG. 2 is a perspective view showing a group of tools that constitute the device. [Figure 2B] FIG. 2 is a perspective view showing a part of the tool group. [Figure 2C] FIG. 10 is a perspective view showing another part of the tool group. [Figure 3A] FIG. 1 is a schematic view of the device during molding, seen from the rear. [Figure 3B] FIG. 1 is a schematic diagram of a front-to-back cross section of the device during molding, viewed from the right. [Figure 4A] FIG. 2 is a plan view schematically showing the start of incremental forming (one example) using the apparatus. [Figure 4B] FIG. 10 is a plan view schematically showing the next molding step. [Figure 4C] FIG. 10 is a plan view schematically showing the subsequent molding step. [Figure 4D] FIG. 2 is a plan view schematically showing the intermediate stage of the first stroke of the incremental forming. [Figure 4E]FIG. 2 is a plan view schematically showing the end of the first stroke of the incremental forming. [Figure 5A] 1A to 1C are a front view, a plan view, and left and right side views schematically showing an example of a molded product having an equal cross-sectional shape. [Figure 5B] 1A to 1C are a front view, a plan view, and left and right side views schematically showing an example of a molded product having a hat-shaped cross section with a constant width and a varying depth at the top. [Figure 5C] 1A to 1C are a front view, a plan view, and left and right side views schematically showing an example of a molded product having a saddle-shaped equal-width hat cross section. [Figure 5D] 1A and 1B are a front view, a plan view, and left and right side views schematically showing an example of a molded product having a saddle-shaped, equal-width hat cross section with a varying depth at the top. [Figure 6A] FIG. 2 is a plan view schematically showing an incremental forming apparatus (another example). [Figure 6B] This is a schematic diagram of the device during molding, seen from the rear. [Figure 7A] This is a front view, a plan view, and left and right side views schematically showing an example of a molded product with a constant depth hat cross section whose top width varies. [Figure 7B] 1A to 1C are a front view, a plan view, and left and right side views schematically showing an example of a molded product having a hat-shaped cross section with varying width and depth at the top. [Figure 7C] 1A and 1B are a front view, a plan view, and left and right side views schematically showing an example of a molded product having a saddle-shaped, equal-depth hat cross section with a varying width at the top. [Figure 7D] 1A to 1C are a front view, a plan view, and left and right side views schematically showing an example of a molded product having a saddle-shaped hat cross section with varying width and depth at the top. DETAILED DESCRIPTION OF THE INVENTION

[0019] One or more components selected from the present specification may be added to the above-described components of the present invention. The contents described in this specification apply not only to the incremental molding apparatus and incremental molding method, but also to the resulting molded product, as appropriate, and may be method-related components or product-related components. Whether any embodiment is best depends on the target, required performance, etc.

[0020] 《Plate material》 (1)Material The plate material (raw material) may be any of iron, aluminum, magnesium, titanium, etc. A typical plate material is a steel plate (for example, a high-tensile steel plate). Here, "based on" means that the material is a pure metal or alloy.

[0021] The thickness of the plate material (plate thickness) may be constant or may vary depending on the region, and is, for example, about 0.3 to 7 mm, or even about 0.5 to 3 mm.

[0022] (2) Form The plate may have a shape according to the desired molded product. The width of the plate may be constant or may vary (for example, tapered). The plate may be rectangular (straight) or curved (arc-shaped, etc.).

[0023] The plate material may be a single plate or a plywood made by joining multiple plates (for example, a steel plate and an aluminum alloy plate). The plate material (raw material) used for incremental forming may be flat, curved, or an intermediate product that has already been processed.

[0024] "tool" Each tool consists of a pair of tools facing each other vertically, and can shape and clamp (grasp) the plate material.

[0025] The shoulders of the middle tool (front middle tool, rear middle tool), right tool (front right tool, rear right tool), and left tool (front left tool, rear left tool) involved in forming the hat-shaped cross section may be rounded. The ridgeline of the shoulder may be straight or curved (e.g., arc-shaped) and may correspond to the (longitudinal) shape of the apex formed in the center of the sheet material. For example, when incrementally forming a hat-shaped cross section molded product whose apex extends in a straight line, the ridgeline of the shoulder may be straight and extend in the front-to-rear direction (molding direction). Furthermore, when incrementally forming a hat-shaped cross section molded product whose apex extends in an arc, the ridgeline of the shoulder may be arc-shaped with a radius of curvature corresponding to the position of the shoulder (e.g., the distance from the center of rotation).

[0026] Between the opposing surfaces of the right and left tools that hold the sheet material, it is advisable to provide a flow adjustment means for adjusting the flow (bulging resistance) of the sheet material flowing from the sides to the center when the sheet material is formed (pushed in) by the middle tool. This helps to suppress wrinkles and other defects that may occur during incremental forming.

[0027] The flow adjustment means may consist of a bead (protrusion) provided between the opposing surfaces of the right and left tools and a bead groove for the bead to escape. The protrusion amount of the bead provided on one side of the opposing surfaces may be adjusted by, for example, changing the bead itself or by adjusting the thickness of an intervening spacer (plate).

[0028] The bead groove provided on the other side of the opposing surface is preferably deep enough not to come into (excessive) contact with not only the bead but also the plate material.

[0029] The side walls (left and right side walls, inner and outer peripheral side walls) of the center tool, right tool, and left tool can have any shape as long as they are not involved in forming or clamping the sheet material. When the side walls are involved in forming a hat-shaped cross section, it is advisable to adjust their inclination and surface configuration (flat, curved, etc.) according to the shape of the top (longitudinal direction).

[0030] The width of the top formed in the center of the workpiece may be constant or variable in the longitudinal direction. To change the width, for example, the middle tool may be provided with a width-changing means for changing the left-right width (the distance between the shoulders). The width-changing means may be realized, for example, by a split tool that divides the middle tool into left and right halves and an adjustment tool that changes the distance between them. Furthermore, the right and left tools may also be displaced (slid) left and right in accordance with the left-right expansion and contraction of the middle tool.

[0031] Actuator The tool is moved up and down by an actuator. The actuator may be equipped with a mechanism that can hold the tool at a desired position. For example, the actuator may be driven by electricity or hydraulics. If an actuator is provided for each tool (for each upper and lower tool), the degree of freedom of incremental forming can be expanded.

[0032] "transfer" It is preferable to provide a transport means that can move the plate material relative to the group of tools by a predetermined amount (length, angle) in the forming direction for each forming operation (each time the front and middle tools are pressed in). Generally, moving the plate material rather than the group of tools makes it easier to achieve a compact and simple device. It is preferable that the transport means be capable of reciprocating the plate material relative to the group of tools. The drive source for the transport means may be, for example, hydraulic, but using an electric drive makes it easier to reverse the direction of movement and control the amount of movement.

[0033] The direction of movement of the plate material by the transfer means may be one-dimensional (X-axis) only, two-dimensional (X-axis and Y-axis) or three-dimensional (X-axis, Y-axis and Z-axis) directions depending on the shape of the molded product. As such a transfer means, an electric actuator consisting of a ball spline, a linear guide or the like, or a robot hand may be used.

[0034] When transferring the plate material itself, it is advisable to grip a portion that will have little effect on the hat shape, such as the front or rear end of the plate material where the apex will be formed.

[0035] 《Molded products》 The hat-shaped cross-section molded product can be used for any purpose or detailed shape, and is used, for example, as structural components for automobile bodies (such as various pillars, rails, members (frames), side sills, center tunnels, roof panels, and underbodies). [Example]

[0036] The present invention will be described in more detail with reference to a specific example of an incremental forming apparatus for forming a plate material (raw material) into a hat-shaped cross section and the forming process performed by the apparatus.

[0037] [First Example] 《Sequential molding device》 (1) Overview An example of incremental forming apparatus D (simply referred to as "apparatus D") is shown schematically in Figure 1, Figures 2A to 2C (collectively referred to as "Figure 2"), and Figures 3A and 3B (collectively referred to as "Figure 3"). Unless otherwise specified, the directions are defined as follows: The directions indicated by arrows in the figures are the front-to-rear direction, the up-down direction, and the left-to-right direction. Up-down is based on the vertical direction, and left-to-right is based on the direction from rear to front. Where appropriate, the case where the direction from rear to front is the direction in which incremental forming progresses (forming direction) will be mainly described.

[0038] The device D includes a front tool group 1, a rear tool group 2, a front actuator group 3 that operates the front tool group 1, a rear actuator group 4 that operates the rear tool group 2, slide tables 61 and 62 (collectively referred to as "slide table 6") that can freely transport a plate material m (e.g., a steel plate) to be formed into a hat-shaped cross section via links 51 and 52 (collectively referred to as "links 5"), and a frame 9 on which these are mounted. The slide table 6 can be moved (displaced) with high precision to any point on a plane (XY coordinate system; X-axis: left-right direction, Y-axis: front-back direction) by an electric actuator (not shown) consisting of a linear guide, a servo motor, etc. The movement of the link 5 in the vertical direction (Z-axis) will be described later.

[0039] (2) Tools The front tool group 1 consists of a front left tool 11, a front right tool 12, and a front middle tool 13 arranged on the left and right sides of the front. The front left tool 11 consists of a pair of a front upper left tool 111 and a front lower left tool 112 arranged above and below on the left side. The front right tool 12 consists of a pair of a front upper right tool 121 and a front lower right tool 122 arranged above and below on the right side. The front middle tool 13 consists of a pair of a front middle upper tool 131 and a front middle lower tool 132 arranged above and below on the center side.

[0040] The rear tool group 2 includes a rear left tool 21, a rear right tool 22, and a rear middle tool 23 arranged on the left and right sides of the rear. The rear left tool 21 consists of a pair of a rear upper left tool 211 and a rear lower left tool 212 arranged above and below on the left side. The rear right tool 22 consists of a pair of a rear upper right tool 221 and a rear lower right tool 222 arranged above and below on the right side. The rear middle tool 23 consists of a pair of a rear middle upper tool 231 and a rear middle lower tool 232 arranged above and below on the center side.

[0041] Beads 1114 and 2114 are fitted into recesses on the underside of the front upper left tool 111 and the rear upper left tool 211. Beads 1214 and 2214 are fitted into recesses on the underside of the front upper right tool 121 and the rear upper right tool 221.

[0042] Furthermore, bead grooves for receiving and releasing beads 1114, 2114, 1214, and 2214 are provided on the upper surface of each of the front lower left tool 112, the rear lower left tool 212, the front lower right tool 122, and the rear lower right tool 222. The depth of each bead groove may be set to such an extent that the clamped plate material m does not come into contact with the groove.

[0043] The resistance to overhang when the sheet material m flows from the left side, which is the flange portion, to the center side, which is the apex, is adjusted by the amount of protrusion of each bead. The amount of protrusion can be changed by the thickness of plates 2115, 2215 (spacers) interposed between the tool and the bead. Such beads (and further plates) correspond to the sheet material flow adjustment means referred to in this invention.

[0044] The downward movement (pushing) of the front middle upper tool 131 and the rear middle upper tool 231 forms the sheet material m into a hat-shaped cross section. At this time, the sheet material m comes into sliding contact with the left shoulder 131a (not shown) and right shoulder 131b of the front middle upper tool 131 and the left shoulder 231a and right shoulder 231b of the rear middle upper tool 231. Similarly, the sheet material m comes into sliding contact with the right shoulder 112b of the front left lower tool 112 and the right shoulder 212b of the rear left lower tool 212 and the left shoulder 122a of the front right lower tool 122 and the left shoulder 222a of the rear right lower tool 222. The corners of each shoulder are rounded (with a radius of curvature: r) to allow the sheet material m to slide smoothly.

[0045] When incrementally forming while rotating the sheet material m relative to each tool group in an arc (see Fig. 4A, etc.), it is preferable that the sliding surface of each shoulder be a curved surface corresponding to the radius of rotation, as shown in Fig. 2C. Specifically, for example, when the center of rotation O is on the right extension line of the tool group, it is preferable that the right shoulders 112b, 212b, the left shoulders 122a, 222a, the left shoulders 131a, 231a, and the right shoulders 131b, 231b be configured with curved surfaces whose ridgelines, as viewed from the center of rotation O, have radii of curvature R1b, R2a, R3a, and R3b, respectively.

[0046] Each tool is a block piece, but they can also be considered to cooperate to form a forming (metal) die. From this perspective, the front middle upper tool 131 and the rear middle upper tool 231 can correspond to punches, and the front middle lower tool 132 and the rear middle lower tool 232 can correspond to punch holders or pads. The front left lower tool 112 and the rear left lower tool 212 and the front right lower tool 122 and the rear right lower tool 222 can correspond to dies. Furthermore, the front left upper tool 111 and the rear left upper tool 211 and the front right upper tool 121 and the rear right upper tool 221 can correspond to die holders or blank holders.

[0047] (3) Actuator The front actuator group 3 comprises front left actuators 311, 312 (not shown), front right actuators 321, 322 (not shown) and front middle actuators 331, 332 which individually operate the front left tools 111, 112, the front right tools 121, 122 and the front middle tools 131, 132, respectively.

[0048] The rear actuator group 4 includes rear left actuators 411, 412, rear right actuators 421, 422, and rear middle actuators 431, 432 that individually operate the rear left tools 211, 212, the rear right tools 221, 222, and the rear middle tools 231, 232, respectively.

[0049] As shown in Fig. 3, each actuator provided for each tool can move the tool up and down and hold it at a predetermined position. Each actuator is, for example, an electric actuator (cylinder) made up of a ball screw, a servo motor, etc.

[0050] 《Sequential molding method》 The incremental forming method will be specifically described while illustrating the process (step) of producing a hat-shaped cross-section molded product from a plate material m using the device D. As an example, the incremental forming method will be described using a case where a plate material m having a substantially fan shape (central angle θ, for example, 60°) is incrementally formed into a hat-shaped product having an arc-shaped band and a uniform cross-section.

[0051] (1) Early period As shown in FIG. 4A, the plate material m is set in the device D. Specifically, the process is as follows: First, the plate material m is placed between the upper and lower tools constituting the front tool group 1 and the rear tool group 2. A gripping piece m1 provided on the front end side of the center of the plate material m is pivotally supported by a pin 511 on the rear end of a rod 513. Similarly, a gripping piece m2 provided on the rear end side of the center of the plate material m is pivotally supported by a pin 521 on the front end of a rod 523.

[0052] The front end of rod 513 is pivotally supported by a sleeve 512 that is provided near the center of slide table 61 and is capable of moving up and down. Similarly, the rear end of rod 523 is pivotally supported by a sleeve 522 that is provided near the center of slide table 62 and is also capable of moving up and down. Sleeves 512 and 522 are capable of moving up and down by a ball spline mechanism. In this way, plate material m can be moved three-dimensionally by the combination (transfer means) of the slide table and the ball spline mechanism that moves up and down.

[0053] Unless otherwise specified, the slide table 6 rotates the plate material m left (counterclockwise) on a horizontal plane around the center O via the link 5. For convenience, the side closer to the center O will be referred to as the "inner side" and the side farther from the center O as the "outer side."

[0054] 4A, the slide table 6 is operated to align the rear end edge of the plate material m with the front tool group 1. The front left tool 11 and the front right tool 12 clamp (hold) the left side (left flange portion / outer flange portion) and the right side (right flange portion / inner flange portion) near the rear end edge of the plate material m from above and below (side holding process / step S10).

[0055] The front middle lower tool 132 is lowered in advance by an amount corresponding to the processing amount of one step of sequential forming (unit processing amount: Δw / for example, about 1 mm). In this state, the front middle upper tool 131 is lowered by Δw to press in the plate material m (forming process / step S11). Note that the front middle upper tool 131 and the front middle lower tool 132 may be lowered approximately simultaneously.

[0056] (2) Sequential molding The front tool group 1 is operated to change from a gripped state in which the top and bottom surfaces of the workpiece m are clamped to a non-gripped state (released state). Specifically, the front left upper tool 111, the front right upper tool 121, and the front middle upper tool 131 are raised by a predetermined release amount (Δh, for example, about 10 mm) taking into account the height of the hat cross section (top depth) and separated from the workpiece m (releasing process / step S20). At this time, the rear tool group 2 remains in the released state.

[0057] The slide table 6 is operated to rotate the released plate material m by a predetermined feed amount (α, for example, 2°) (transfer step / step S21). At this time, as shown in FIG. 4B, the rear end of the plate material m is aligned approximately parallel to the rear tool group 2.

[0058] The rear left tool 21, rear right tool 22, and rear middle tool 23 that make up the rear tool group 2 grip the outer left flange portion, inner right flange portion, and central apex portion formed near the rear end edge of the sheet material m from above and below (gripping process / step S22). The gripping of the apex portion by the rear middle tool 23 and the gripping of the flange portions by the rear left tool 21 and rear right tool 22 may be performed approximately simultaneously or may be performed one before the other.

[0059] As in step S10, the left and right parts of the plate material m are gripped from above and below by the front left tool 11 and the front right tool 12 (side gripping step / step S23).Furthermore, as in step S11, the front middle tool 13 presses the center of the plate material m to form the top (forming step / step S24).

[0060] Thereafter, the front tool group 1 and the rear tool group 2 are operated to release the gripped state of the workpiece m. Specifically, the front upper left tool 111, the front upper right tool 121, the front upper middle tool 131, and the rear upper left tool 211, the rear upper right tool 221, and the rear upper middle tool 231 are each raised by Δh to release the workpiece m (releasing step / step S30). Thereafter, as shown in FIG. 4C, the above-described steps S21 to S24 are repeated.

[0061] Figure 4D shows the state where this incremental forming has progressed to near the center of the sheet material m (Σα ≒ θ / 2), and Figure 4E shows the state where incremental forming has progressed to near the top edge of the sheet material m (Σα ≒ θ).

[0062] By one incremental forming process from the state shown in FIG. 4A to the state shown in FIG. 4E, a hat-shaped product with a uniform cross section and a curved arc with a top depth of Δw (for example, 1 mm) is obtained.

[0063] To form a deeper crest, the incremental forming process described above can be repeated. At this time, after each cycle, the sheet material m that has been subjected to incremental forming can be returned to the state shown in FIG. 4A and the incremental forming process described above can be repeated. However, it is more efficient to feed the sheet material m in the reverse direction (clockwise) from the state shown in FIG. 4E and repeat the incremental forming process. In the latter case, the operation of the front tool group 1 and the rear tool group 2 described above are switched between the forward and backward passes. The reciprocating movement of the sheet material m can be stopped when a crest of the desired depth is formed (or at the end of any forward pass).

[0064] 《Molded products》 Figures 5A to 5D (collectively referred to as "Figure 5") show examples of hat-shaped cross-section molded products obtained by incremental molding using device D. A hat-shaped cross-section molded product curved like an arc band (simply referred to as a "curved product") is obtained by the method already described. A hat-shaped cross-section molded product extending in a straight line (simply referred to as a "straight product") is obtained by feeding the sheet material m linearly in the forward and backward directions using slide table 6. In this way, the overall shape of the molded product is adjusted by the transport mode of the sheet material m.

[0065] The shape of the top and changes in the longitudinal cross section can be adjusted by the shape, structure, operation, etc. of the front middle upper tool 131, rear middle upper tool 231, front left lower tool 112, rear left lower tool 212, front right lower tool 122 and rear right lower tool 222.

[0066] Figure 5A shows examples of a straight product s11 and a curved product c11 with uniform cross-sections, where the width and depth of the apex p are both constant. The figure also shows a schematic front view, plan view, and left and right side views of each product (same below). The widths of the left flange f1, right flange f2, outer flange fo, and inner flange fi formed on both sides of the apex p are adjusted according to the target flange width of the molded product, and correspond to the width of the sides of the hat-shaped cross-section (same below).

[0067] 5B shows examples of a straight product s12 and a curved product c12 with equal widths whose apex depths change at a constant rate in the longitudinal direction. The change in apex depth can be achieved, for example, by varying the amount of descent (Δw) of the front middle tool 13 and the rear middle tool 23 along the longitudinal direction. In this case, the lower surfaces of the front middle upper tool 131 and the rear middle upper tool 231 and the upper surfaces of the front middle lower tool 132 and the rear middle lower tool 232 may be inclined surfaces along the longitudinal direction.

[0068] 5C shows examples of a saddle-shaped straight product s13 and a saddle-shaped curved product c13, which have uniform cross sections with constant apex width and depth and are curved upward in the longitudinal direction. The saddle-shaped formation can be achieved, for example, by varying the vertical movement of the front tool group 1 and the rear tool group 2 along the longitudinal direction. In this case, the lower surfaces of the front upper-left tool 111, front upper-right tool 121, front upper-center tool 131, rear upper-left tool 211, rear upper-right tool 221, and rear upper-center tool 231, and the upper surfaces of the front lower-left tool 112, front lower-right tool 122, front lower-center tool 132, rear lower-left tool 212, rear lower-right tool 222, and rear lower-center tool 232 may be curved along the longitudinal direction.

[0069] 5D illustrates a saddle-shaped straight product s14 and a saddle-shaped curved product c14, both of which have a constant width and whose apex depth varies longitudinally. As described above, the apex depth can be varied by varying the amount of lowering (Δw) of the front middle tool 13 and the rear middle tool 23 along the longitudinal direction. Furthermore, the saddle-shaped forming can be achieved by forming the lower surfaces of the front upper-left tool 111, the front upper-right tool 121, the rear upper-left tool 211, and the rear upper-right tool 221 and the upper surfaces of the front lower-left tool 112, the front lower-right tool 122, the rear lower-left tool 212, and the rear lower-right tool 222 into curved surfaces along the longitudinal direction of the flanges, and further by forming the lower surfaces of the front upper-middle tool 131 and the rear upper-middle tool 231 and the upper surfaces of the front lower-middle tool 132 and the rear lower-middle tool 232 into curved surfaces along the longitudinal direction of the apex.

[0070] [Second Example] 《Sequential molding device》 Another example of an incremental forming apparatus D2 (simply referred to as "apparatus D2") is shown schematically in Figures 6A and 6B (collectively referred to as "Figure 6"). Members and the like that are the same as those in the first embodiment are given the same reference numerals, and detailed descriptions thereof are omitted where appropriate. As in the first embodiment, the directions indicated by arrows in the figures are the front-rear direction, the up-down direction, and the left-right direction.

[0071] (1) In device D2, the front and rear middle tools 13 and 23 are each made into a separate tool, which allows the left and right widths of the front and rear middle tools 13 and 23 to be increased or decreased. This allows for the production of molded products with hat-shaped cross sections whose top width changes in the longitudinal direction.

[0072] Specifically, the configuration of each tool is as follows: The front-middle-upper tool 131 consists of a front-middle-upper-left tool 1311, a front-middle-upper-right tool 1312, and a front-middle-upper rod 1313 that connects them in the middle. The front-middle-lower tool 132 consists of a front-middle-lower-left tool 1321, a front-middle-lower-right tool 1322, and a front-middle-lower rod 1323 that connects them in the middle (these are not shown).

[0073] The rear middle upper tool 231 is made up of a rear middle upper left tool 2311, a rear middle upper right tool 2312, and a rear middle upper rod 2313 connecting them in the middle. The rear middle lower tool 232 is made up of a rear middle lower left tool 2321, a rear middle lower right tool 2322, and a rear middle lower rod 2323 connecting them in the middle.

[0074] The front middle upper rod 1313, the front middle lower rod 1323, the rear middle upper rod 2313 and the rear middle lower rod 2323 (collectively referred to as "connecting rods") each have a reverse thread at the left and right ends (for example, if the left end is a left-handed screw, the right end is a right-handed screw), and by rotating them forward or backward, the left and right width of the front middle tool 13 and the rear middle tool 23 can be expanded or contracted.

[0075] The rotation of the connecting rod (amount of rotation, direction of rotation) may be adjusted manually at the appropriate time during incremental molding, but it is preferable that it be adjusted continuously or discretely by a controlled electric actuator (such as a servo motor). Note that it is preferable that a locking mechanism be provided to stop the rotation of the connecting rod so that the left-right width of the front middle tool 13 and the rear middle tool 23 does not change during one molding step (while the front middle upper tool 131 and the rear middle upper tool 231 are descending).

[0076] (2) Furthermore, it is preferable that the front left tool 11, the front right tool 12, the rear left tool 21, and the rear right tool 22 are also able to move (slide) left and right relative to the frame 9. This allows for greater freedom in the shape of the molded product with a hat-shaped cross section.

[0077] The expansion and contraction of the left-right width of the front middle tool 13 and the rear middle tool 23 and the left-right displacement of the front left tool 11, the front right tool 12, the rear left tool 21 and the rear right tool 22 may be performed in conjunction (synchronized) or separately (asynchronously).

[0078] The left and right displacements of the front left tool 11, the front right tool 12, the rear left tool 21, and the rear right tool 22 may also be adjusted manually at an appropriate time during incremental molding, or may be adjusted continuously or discretely by a controlled electric actuator (such as a servo motor). Also, a holding mechanism may be provided to prevent these left and right displacements from occurring during at least one molding step (while the front middle upper tool 131 and the rear middle upper tool 231 are being lowered).

[0079] 《Molded products》 7A to 7D (collectively referred to as "FIG. 7") show examples of hat-shaped cross-section molded products obtained by incremental molding using device D2. As in the first embodiment, hat-shaped cross-section molded products that are curved like an arc band are referred to as "curved products," and hat-shaped cross-section molded products that extend in a straight line are referred to as "straight products."

[0080] All of the formed products are obtained based on the manufacturing method and steps described in Example 1. However, the shape of each formed product can be realized by adjusting the transfer form of the sheet material m, the shape (particularly the shoulder portions) and operation of each tool (particularly the front middle upper tool 131, the rear middle upper tool 231, the front left lower tool 112, the rear left lower tool 212, the front right lower tool 122, and the rear right lower tool 222), as well as the expansion / contraction of the left / right width of the front middle tool 13 and the rear middle tool 23, and the left / right displacement of the front left tool 11, the front right tool 12, the rear left tool 21, and the rear right tool 22.

[0081] FIG. 7A shows examples of a straight product s21 and a curved product c21, in which the depth of the top is constant and the width of the top changes at a constant rate in the longitudinal direction.

[0082] FIG. 7B shows a straight product s22 and a curved product c22 in which the depth and width of the top portion both change at a constant rate in the longitudinal direction.

[0083] FIG. 7C shows examples of a saddle-shaped straight product s23 and a saddle-shaped curved product c23, in which the top depth is constant and the top width changes at a constant rate in the longitudinal direction.

[0084] FIG. 7D shows examples of a saddle-shaped straight product s24 and a saddle-shaped curved product c24, in which the depth and width of the top both change at a constant rate in the longitudinal direction.

[0085] According to the present invention, it is possible to efficiently produce a variety of hat-shaped cross-section molded products even in small quantities. [Explanation of symbols]

[0086] m plate material D Sequential molding equipment 1. Previous Tools 2. Post-processing tools 3 Front actuator group 4 Rear actuator group

Claims

1. An apparatus for successively forming a plate material into a hat-shaped cross section with a central portion protruding from the left and right side portions, a front tool group and a rear tool group disposed in front and rear along the forming direction of the plate material; a front actuator group and a rear actuator group that operate the front tool group and the rear tool group, respectively; The front tool group includes: a front left tool provided opposite to the top and bottom and configured to clamp a left side portion of the plate material; a front right tool provided opposite to the upper and lower sides and configured to clamp a right side portion of the plate material; front and middle tools that are provided opposite to each other above and below and that form or clamp the central portion of the plate material, The group of tools includes: a rear left tool provided opposite to the upper and lower sides and configured to clamp a left side portion of the plate material; a rear right tool provided opposite to the upper and lower sides and configured to clamp a right side portion of the plate material; and a rear middle tool that is provided opposite to the upper and lower parts and that forms or clamps the central part of the plate material, The front actuator group includes: a front left actuator that actuates the front left tool; a front right actuator that actuates the front right tool; a front and middle actuator that operates the front and middle tool, The rear actuator group includes: a rear-left actuator that actuates the rear-left tool; a rear right actuator that actuates the rear right tool; and a rear middle actuator that operates the rear middle tool.

2. The incremental forming apparatus according to claim 1 , further comprising a flow adjusting means for adjusting the flow of the plate material from the side portion to the center portion.

3. The incremental forming apparatus according to claim 1, further comprising a width changing means for changing the left-right width of the front middle tool and the rear middle tool.

4. 2. The incremental forming apparatus according to claim 1, further comprising a transfer means for transferring the plate material relatively and incrementally along the forming direction.

5. 5. The incremental forming apparatus according to claim 4, wherein the transfer means is capable of relatively reciprocating the plate material.

6. The incremental forming apparatus according to claim 1 , wherein the forming direction is linear and / or curved.

7. A method for incrementally forming the plate material into a hat-shaped cross section using the incremental forming apparatus according to any one of claims 1 to 6.

8. a transfer step of transferring the ungriped plate material to a predetermined position; a gripping step of gripping the plate material after the transfer step by the post-tool group; a forming step of forming the plate material held by the rear tool group with the front tool group; 8. The incremental forming method according to claim 7, wherein the steps of:

Images