Apparatus and method for forming flat wire into a hairpin shape for use in the manufacture of motor stators
The apparatus addresses the challenges of forming flat wire into hairpin shapes by using a multi-unit system with actuators and die structures to achieve parallel legs, ensuring high productivity and uniform quality in motor stator production.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-05-17
- Publication Date
- 2026-06-04
AI Technical Summary
Conventional methods for forming flat wire into hairpin shapes for motor stators face challenges in achieving high production efficiency, uniform product quality, and addressing the spring-back effect that prevents the legs of the U-shaped hairpin from remaining parallel, while also requiring a compact and easily adjustable apparatus for automated production lines.
An apparatus comprising a stationary base plate with wire supports, a first forming unit for forming a V-shaped bridge and parallel legs, a second forming unit to compensate for spring-back by pushing the legs inward, and a third unit to finalize the three-dimensional shape, using actuators and movable die structures to ensure precise and parallel leg alignment.
The apparatus enables high productivity, uniform product quality, and compact design, reducing space and maintenance downtime, while ensuring the legs of the hairpin remain parallel despite spring-back, facilitating rapid product discharge and easy adjustment for various configurations.
Smart Images
Figure 2026518122000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to an apparatus and method for forming a flat wire into a hairpin shape having a general U-shape, with two substantially parallel legs connected by a bridge portion, for use in the manufacture of motor stators.
[0002] prior art With the development of the automotive industry in the field of vehicles equipped with new propulsion systems, market demand for electric and hybrid vehicles has increased significantly. The electric propulsion system, as a component of electric or hybrid vehicles, has a significant impact on the vehicle's output, economic efficiency, comfort, safety, and service life. As the core of the electric propulsion system, the performance of the electric motor directly determines the vehicle's performance to a very large extent. Electric motors with stator windings containing flat wire hairpins have proven particularly advantageous. Flat wire motor windings are characterized by small internal gaps, high slot filling rates, and wide contact areas between wires and between the windings and the iron core, resulting in good heat dissipation and heat conduction performance, low temperature rise, and improved overall motor performance. For this reason, electric motors with flat wire hairpin windings are entering the large-scale mass production stage. However, enormous challenges arise for large-scale manufacturing lines of flat wire hairpins.
[0003] Examples of apparatus for forming wire into hairpin shapes are known from documents US11496028B2 and US11848589B2. Conventional solutions provide a vertically operating mold for forming the wire into a hairpin shape. However, conventional solutions do not enable high production efficiency and uniform product quality.
[0004] The primary need perceived in this field is to provide equipment with a simple configuration and reduced footprint, adapted for use as part of a fully automated production line for the large-scale manufacture of electric motors.
[0005] Another challenge to be addressed is to provide equipment capable of reliably producing high and uniform finished product quality. In this regard, a specific challenge encountered when forming hairpins is that, at the end of the forming operation, the two legs of the formed product may be subjected to a spring-back effect, preventing the two legs of a U-shaped hairpin from remaining parallel and in precise positions relative to each other.
[0006] Therefore, further improvements are needed in this field. Objective of the present invention Therefore, the object of the present invention is to solve all of the above problems by providing an apparatus and method for forming flat wires into a hairpin shape for use in the manufacture of motor stators, which enables high efficiency and high productivity while ensuring very good and uniform quality of the finished product.
[0007] A further, more specific object of the present invention is to provide a device for ensuring that the two legs of a finished hairpin are properly and substantially parallel in configuration, despite any spring-back effect that these legs may experience after the forming operation.
[0008] Another object of the present invention is to enable the rapid exhaust of finished products from the apparatus, thereby enabling the rapid loading of new wires, and thus improving productivity.
[0009] Another object of the present invention is to make the apparatus easily and flexibly adjustable to any new configuration and size of the finished product to be obtained. [Overview of the Initiative]
[0010] To achieve one or more of the above objectives, the present invention provides an apparatus for use in the manufacture of a motor stator for forming a flat wire having a flat cross section into a hairpin shape having a general U-shape, including two substantially parallel legs connected by a bridge section, the apparatus comprising: a stationary base plate; a pair of wire stationary supports mounted on the base plate and configured to hold the substantially straight wire along a horizontal support direction by holding the wire at two spaced-apart positions; a first forming unit slidably mounted on the base plate along a first horizontal axis perpendicular to the horizontal wire support direction and adapted to be moved by an actuator from a first retracted position to a second forward position; and a first forming unit gripped by the base plate and configured to cooperate with a mold member of the first forming unit as a result of the first forming unit moving from its first retracted position to the second forward position in order to form the wire into a two-dimensional formed semi-workpiece including a V-shaped bridge section and two substantially parallel legs. The apparatus provides a stationary die structure; a second forming unit slidably mounted on the base plate along the first horizontal axis and adapted by an actuator to move from a third retracted position to a fourth forward position in the opposite direction to the direction in which the first forming unit moves from the first retracted position to the second forward position; a lateral extrusion member configured such that the second forming unit slightly pushes the two legs laterally inward as a result of the second forming unit moving to its fourth forward position, in order to compensate for any spring-back effect of the two legs, thereby so that when the second forming unit is returned to its third retracted position, the two legs remain substantially parallel to each other; and a third forming unit movable perpendicular to the base plate and moved by an actuator from an elevated position to a lowered position, wherein in the lowered position the mold member of the third forming unit cooperates with the stationary mold member of the die structure to bring the two-dimensional formed semi-workpiece into a final three-dimensional shape.
[0011] In terms of further features, the mold member of the first forming unit is the pointed forward portion of the first forming unit, and the die structure includes a die member configured to cooperate with the mold member of the first forming unit when the first forming unit is in its second forward position, in order to form the central portion of the wire into a V-shaped bridge portion.
[0012] According to further features, the two wire stationary supports are positioned and configured to act as additional die members, such that when the first forming unit is moved to its second forward position, the central portion of the wire is pushed between and beyond the two supports by the die member of the first forming unit, forcing the two opposing portions of the wire to bend to form the two substantially parallel legs, thereby causing the forward movement of the first forming unit to result in the formation of the V-shaped bridge portion and the two parallel legs of the two-dimensional semiworkpiece.
[0013] In a preferred example, the second forming unit has a sliding structure that is movable along the first axis on the base plate; a lateral extrusion member in the form of two lateral arms gripped by the sliding structure and movable transversely to the first axis relative to the sliding structure; a wire engagement element gripped by the lateral arms and configured to engage the two legs of the two-dimensional semiworkpiece laterally from the outside; and a cam means configured to cause the lateral movement of the lateral arms as a result of the second forming unit moving from a third retracted position to a fourth forward position, and to cause the engagement element to push the two legs of the two-dimensional formed semiworkpiece laterally inward toward each other so that when the second forming unit is returned to its third retracted position, the two legs of the two-dimensional semiworkpiece return to a position substantially parallel to each other.
[0014] Preferably, the two lateral arms are mounted so as to be rotatable about a vertical axis on the slide structure of the second forming unit, and the cam means includes a cam surface provided on the lateral arms and configured to engage a cooperating member, so that when the slide structure of the second forming unit moves from the third retracted position to the fourth advanced position, the lateral arms rotate toward each other, and the wire engagement element gripped by the lateral arms pushes the two legs of the two-dimensional semiworkpiece toward each other.
[0015] Preferably, the wire engagement element is a freely rotatable roller gripped by the lateral arm.
[0016] Preferably, the cooperating member is a freely rotatable roller gripped by a stationary support, wherein a spring is operably interposed between the rotating lateral arm and the postponement slide structure of the second forming unit, biasing each of the rotating lateral arms relative to the respective cooperating roller.
[0017] Preferably, each cooperative roller is adjustable in position along a direction perpendicular to the first axis.
[0018] Due to the features described above, the present invention can be advantageously used in automated manufacturing lines. In the present invention, the final three-dimensional shape of the hairpin can be obtained very easily by first forming a two-dimensional U-shaped semi-workpiece, and then bringing this two-dimensional semi-workpiece into the final three-dimensional shape. Furthermore, the provision of a first and second forming unit that are horizontally movable makes it possible to increase productivity and also makes it easier to discharge the finished product at the end of the forming operation. Moreover, by providing a lateral pressing member in the second forming unit configured to slightly push the two legs of the two-dimensional semi-workpiece inward from the side, it is possible to obtain a final product with two parallel legs despite any spring-back effect that the legs may experience after the forming operation.
[0019] The device of the present invention has a relatively simple and compact structure, and the occupied space is reduced. Since the die members cooperating with the first forming unit and the third forming unit are arranged adjacent to each other, the space is concentrated, and a plurality of auxiliary systems are shared, so that the occupied area is greatly reduced. Furthermore, the length of the discharging equipment for discharging the formed hairpins can be greatly reduced, thus reducing the investment costs of the manufacturing line and energy consumption.
[0020] The device of the present invention can be easily and accurately adjusted according to any specific form and size of the hairpin to be obtained. Each forming unit is independently adjustable while maintaining high operating accuracy. Therefore, also, the downtime for the maintenance and adjustment of the device is greatly reduced, thereby reducing production losses.
[0021] In the device of the present invention, the mounting operation is simple, the adjustment operation is simple and convenient, and the maintenance operation is convenient. The assembly time, debugging time and maintenance time can be greatly shortened, thereby greatly improving the operating rate of the manufacturing line.
Brief Description of the Drawings
[0022] Further features and advantageous points of the present invention will become apparent from the following description with reference to the accompanying drawings given merely as non-limiting examples. [Figure 1] It is a top view of an embodiment of the device according to the present invention. [Figure 2] It is a side view of the device of FIG. 1. [Figure 3] It is a perspective view of the devices of FIGS. 1 and 2. [Figure 4] It is an enlarged top view of the details of the device of the present invention. [Figure 5] It is another perspective view of the device of the present invention. [Figure 6] It is a view showing a V-shaped semi-finished product. [Figure 7]This is a schematic diagram of a two-dimensional U-shaped semi-worked product obtained in the first stage of the forming operation using the apparatus of the present invention. [Figure 8] This is a schematic diagram of a final product having a three-dimensional shape, obtained using the apparatus of the present invention. [Figure 9] This figure shows an enlarged top view of the first forming unit of the apparatus according to the present invention, in two different operating positions. [Figure 10] This figure shows an enlarged top view of the first forming unit of the apparatus according to the present invention, in two different operating positions. [Figure 11] This is an enlarged top view of the second forming unit of the apparatus according to the invention. [Figure 12] Figure 11 is a detailed perspective view of the second forming unit. [Figure 13] This diagram shows the operating principle of the second forming unit. [Figure 14] This diagram shows the operating principle of the second forming unit. [Figure 15] This is a perspective view showing a preferred embodiment of the apparatus according to the present invention at the end of the forming operation. [Figure 16] This is an enlarged perspective view of a die structure having mold members that cooperate with a first forming unit and a third forming unit. [Figure 17] This figure shows another schematic diagram of the two-dimensional U-shaped semi-worked product shown in Figure 7. [Figure 18] Another schematic diagram of the final product shown in Figure 8. [Figure 19] This is another perspective view of the apparatus of the present invention during the final product discharge operation. [Figure 20] Figure 19 is an enlarged perspective view of the apparatus, illustrating the discharge operation of the final product. [Modes for carrying out the invention]
[0023] The accompanying drawings merely illustrate preferred embodiments of the apparatus according to the present invention for use in the manufacture of motor stators, for forming a flat wire into a hairpin shape having a general U-shape with two substantially parallel legs connected by a bridge. Figures 8 and 18 show two examples of the finished product to be obtained, namely a hairpin H formed in a three-dimensional shape, including two substantially parallel legs H1 and a bridge H2 connecting the two legs H1.
[0024] In the drawings, the apparatus of the present invention is generally shown as 1. Apparatus 1 comprises a stationary base plate 11 and a pair of stationary supports 53 fixed to the base plate 11 (more clearly shown in Figures 9, 10 and 15). Preferably, the supports 53 are mounted on the base plate 11 so as to be adjustable in position along a direction parallel to a first longitudinal horizontal axis X of apparatus 1 and / or along a horizontal direction perpendicular to axis X. The supports 53 are configured to hold a substantially linear wire 52 along the horizontal support direction perpendicular to axis X of the apparatus. The two supports 53 hold the wire 52 in two spaced-apart positions (clearly shown in Figure 9), so that the central portion of the wire 52 can be freely engaged by the mold member of the first forming unit of apparatus 1, as described below.
[0025] As described above, the apparatus of the present invention is configured to form flat wire, i.e., a wire having a substantially flat cross-section, into a hairpin shape as shown in Figure 8 or Figure 18. In this description and the following claims, the terms “flat wire” and “flat cross-section” are used to refer to a non-circular cross-section of a wire that includes two opposing faces which are substantially planar and parallel to each other. However, the present invention is also applicable in principle to the formation of wires having a circular cross-section.
[0026] This disclosure and accompanying drawings do not include a description of means for loading a wire 52 onto two supports 53 of the apparatus 1 of the present invention. These loading means may be in any known form and are preferably configured to allow fully automated loading operations, for example, with the assistance of a robot. Figure 5 of the drawings shows one embodiment in which a clamp jaw 51 for holding the wire is also provided in the apparatus according to the present invention.
[0027] The apparatus of the present invention comprises a first forming unit 12, a second forming unit 13, and a third forming unit 21.
[0028] The first forming unit 12 is in the form of a sliding table that is slidably mounted on the base plate 11 along a first horizontal axis X that is perpendicular to the horizontal direction in which the wire 52 is supported.
[0029] As shown more clearly in Figures 9, 10, and 19, the first forming unit 12 is slidable on two parallel and spaced-apart rails 11A fixed to the upper surface of the base plate 11.
[0030] The first forming unit 12 can be moved between a first retracted position (shown in Figures 1, 3, 5, and 9) and a second forward position (shown in Figure 10) using an actuator 3, preferably in the form of a pneumatic cylinder. The first forming unit 12 includes a forward portion that defines the tip-shaped mold member 14.
[0031] As shown in Figures 9 and 10, when the first forming unit 12 is in its first retracted position, the mold member 14 is positioned upstream along the horizontal direction in which the wire 52 is supported (referencing the direction of its movement to its forward position). When the first forming unit 12 is in its second forward position, the mold member 14 is beyond the direction in which the wire 52 is originally supported. As a result of the first support unit 12 moving from its first retracted position to its second forward position, the mold member 14 engages with the center of the wire 52 and presses the center of the wire 52 against the stationary mold 32, so that the stationary mold 32 forms part of the die structure 31 and is fixed on the base plate 11. In this embodiment, the mold member 14 of the first forming unit 12 and the cooperating stationary mold member 32 cause the wire 52 to take the V shape shown in Figure 6. However, in the illustrated example, as the first forming unit 12 moves from its first retracted position to its second forward position, the wire 52 is formed in one step into a two-dimensional U-shaped semi-worked product H' having two legs H1' and a bridge H2', as shown in Figure 7. This result is achieved by the forward movement of the mold member 14, which causes the central portion of the wire 52 to pass between and over two portions 53A of the support 53, which is positioned to force and bend the wire 52 into a U-shape, as shown in Figure 10.
[0032] Preferably, the position of the support portion 53A is adjustable in both the direction along the rail 11A and the horizontal direction perpendicular to the rail 11A, depending on the shape and size of the two-dimensional U-shaped semi-workpiece to be obtained. As shown more clearly in Figure 16, each support portion 53A is preferably provided with a vertical cylindrical pad 53B to facilitate the sliding contact of the wire with respect to the support portion 53A.
[0033] As is clear from the above description, the first forming unit of the apparatus according to the present invention is configured to operate along the horizontal direction, for example, to form a two-dimensional U-shaped semi-worked product H as shown in Figures 7 and 17. I This can be achieved in a single step.
[0034] As shown, the apparatus of the present invention further comprises a second forming unit 13 in the form of a sliding table 13A, which is slidably mounted on a base plate 11 along a first horizontal axis X. In the illustrated example, the second forming unit 13 is slidably mounted on the same guide rail 11A on which the first forming unit 12 is slidably mounted. In this embodiment, the configuration of the apparatus can be simplified and the number of components can be reduced. However, the second forming unit may be slidably mounted on a different rail from the rail on which the first forming unit 12 is mounted.
[0035] The second forming unit 13 can be moved between a third retracted position and a fourth forward position using an actuator 4, which is preferably in the form of a pneumatic cylinder, with its body mounted on a base plate 11. The first forming unit 12 and the second forming unit 13 are positioned on sides facing the central frame 2 mounted on the base plate 11. The second forming unit 13 is configured such that when the first forming unit 12 is moved from its first retracted position to its second forward position, or when it is moved from its third retracted position to its fourth forward position, its direction of movement is in the opposite direction to the direction of movement of the first forming unit 12.
[0036] Referring particularly to Figures 11 and 12, the second forming unit 13 is provided with two lateral extrusion members 46, which form a two-dimensional U-shaped semi-worked product H I The two legs H1 I Push the two legs H1 slightly inward and to the side. I It is configured to compensate for any spring-back effect, thereby, when the second forming unit 13 is returned to its third retracted position, the two legs H1 I They will essentially remain parallel to each other.
[0037] In the illustrated example, the two lateral extrusion members 46 are in the form of two lateral arms, which are gripped by the structure of the second forming unit 13 and are configured to be movable transversely with respect to the first axis X. In the illustrated example, the two lateral arms 46 are mounted so as to be rotatable around a vertical axis 42 on two forward projection supports 41 of the slide table 13A of the second forming unit 13.
[0038] According to the present invention, a cam mechanism is provided, which is configured to cause lateral movement of the lateral arm 46 as a result of the second forming unit 13 moving from its third retracted position to its fourth forward position, and in this embodiment, the element 54 of the arm 46 is a two-dimensional U-shaped semi-workpiece H I The two legs H1 I When the second forming unit 13 is pushed laterally inward, and therefore returns to the third retracted position, the two legs H1 of the two-dimensional semi-workpiece H1 I However, despite any spring-back effect, they return to a position substantially parallel to each other.
[0039] In the illustrated embodiment, the engaging element 54 gripped by the lateral arm 46 is a freely rotatable roller. In the illustrated example, the cam means includes a chamfered surface 46A on the outer side of the lateral arm 46, configured to cooperate with each cooperating member 45. In the illustrated example, the cooperating member 45 is a freely rotatable roller (see also Figure 12) that engages with the chamfered surfaces 46A of the two lateral arms 46.
[0040] Two springs 43 are provided to bias each lateral arm 46 against the cooperative roller 45. Each spring 43 is movably interposed between each arm 46 and the bracket 41A of each support 41, as is shown more clearly in Figure 12.
[0041] Due to the above structure and arrangement, the movement of the second forming unit 13 from its retracted position to its advanced position causes the chamfered surfaces 46A of the two arms 46 to progressively engage with the cooperating roller 45. As a result, the two arms 46 are forced to rotate towards each other. Thus, using the engaging roller 54, the two legs H1 I of the two-dimensional U-shaped semi-finished product H I are pushed towards each other laterally inwards.
[0042] As clearly shown in FIG. 12, the position along the transverse direction with respect to the first axis X of each cam cooperating roller 45 can be adjusted by any known means (also by the screw adjustment device in the illustrated example).
[0043] The above operation is further illustrated in the drawings of FIGS. 13 and 14, which schematically show the two-dimensional U-shaped semi-finished product H during and after the engagement of the engaging roller 54 with the leg H1 I of the two-dimensional U-shaped semi-finished product H I to the leg H1.
[0044] As shown, the device according to the invention comprises a third forming unit 21 which is movable in a direction perpendicular to the base plate 11 and is adapted to move between a raised position and a lowered position by means of an actuator. The die member 22 of the third forming unit 21 (see FIG. 16) cooperates with the upper surface 34 of the die structure 31 to bring the two-dimensional U-shaped semi-finished product H I to the final hairpin H having a three-dimensional shape (FIG. 18).
[0045] In the illustrated example, the actuator of the third forming unit 21 is a pneumatic cylinder 5 whose axis is vertically oriented and which is supported on a cross member 2B straddling between the two upper ends of two columns 2A forming part of the frame 2. The configuration of the frame 2 shown is merely an example.
[0046] When the die member 22 of the third forming unit 21 is moved from its raised position to its lowered position, the U-shaped semi-finished product H IThe central bridge portion is pressed between the lower end of the mold member 22 and the upper edge of the stationary mold member 34 (see Figure 16), and the desired final three-dimensional shape shown in Figures 8 and 18 is obtained.
[0047] The operation of the above device is as follows:
[0048] First, the wire 52 is positioned on two supports 53, for example, with the assistance of the clamp jaw 51 in Figure 5. Once the wire is loaded, the actuator 3 of the first forming unit 12 is activated, causing the mold member 14 of the first forming unit 12 to engage with the center of the wire 52, bringing the wire 52 toward the die member 32, while the opposing portions of the wire 52 are forced and bent by the support portions 53A toward a two-dimensional U-shaped semi-workpiece H'. With the first forming unit 12 in this position, the actuator 4 of the second forming unit 13 is activated, thereby forcing the lateral arm 46 by the cooperative roller 45, which then bends the two-dimensional U-shaped semi-workpiece H' through the engaging roller 54. I The two legs H1 I Push it laterally inward. In this embodiment, when the second forming unit 13 returns to its retracted position, the two-dimensional U-shaped semi-worked product H I The two legs H1 I It returns to a substantially parallel position despite any spring-back effect. Before or after the second forming unit 13 returns to its retracted position, the actuator 5 of the third forming unit 21 is activated, so that the cooperation of the vertically moving mold member 22 and die member 34 forms a two-dimensional U-shaped semi-worked product H I This is reflected in the three-dimensional shape of the final product H (Figure 18).
[0049] After all these operations are completed, the first forming unit 12, the second forming unit 13, and the third forming unit 21 return to their starting positions (see Figure 19), and thus the final product H falls freely by gravity onto the sliding surface 6A of the support 6, which is gripped by the base plate 11, as shown in Figure 20. In this embodiment, the final product can be easily and rapidly transported to a position where it can be moved to a station on another production line.
[0050] Naturally, while the principles of the present invention remain the same, the details of the configuration and embodiments may differ extensively from those described merely as examples, without departing from the scope of the invention as defined in the appended claims. (Other possible items) (Item 1) An apparatus for forming a flat wire having a flat cross-section into a hairpin (H) shape having a general U-shape, which includes two substantially parallel legs (H1) connected by a bridge portion (H2), for use in the manufacture of a motor stator, wherein the apparatus Static base plate (11); A pair of wire restraint supports (53) are provided on the base plate (11) and configured to hold the substantially straight wire (52) along the horizontal support direction by holding the wire (52) at two spaced-apart positions; A first forming unit (12) is slidably mounted on the base plate (11) along a first horizontal axis (X) perpendicular to the direction of the horizontal wire support, and is adapted to be moved by an actuator (3) from a first retracted position to a second forward position; A stationary die structure (31, 32, 53A) is configured to cooperate with the mold member (14) of the first forming unit (12) as a result of the first forming unit (12) moving from its first retracted position to its second forward position, in order to form the wire (52) into a two-dimensional formed semi-workpiece (H') including a V-shaped bridge portion (H2') and two substantially parallel leg portions (H1'); A second forming unit (13) is slidably mounted on the base plate (11) along the first horizontal axis (X) and is adapted to be moved by an actuator (4) from a third retracted position to a fourth forward position in the opposite direction to the movement of the first forming unit (12) from the first retracted position to the second forward position; The second forming unit (13) is configured to compensate for any spring-back effect of the two legs (H1'), thereby slightly pushing the two legs (H1') of the two-dimensional formed semi-workpiece (H') laterally inward as a result of the second forming unit (13) moving to its fourth forward position, so that the two legs (H1') remain substantially parallel to each other when the second forming unit (13) is returned to its third retracted position; and The third forming unit (21) is movable perpendicular to the base plate (11) and is moved from an upward position to a downward position by an actuator (5). In the downward position, the mold member (22) of the third forming unit (21) cooperates with the stationary mold member (34) of the die structure (31, 32, 34, 53A) to adapt the two-dimensional formed semi-workpiece (H') to the final three-dimensional shape (H). A device equipped with the following features. (Item 2) The apparatus according to item 1, wherein the mold member (14) of the first forming unit (12) is the pointed forward portion of the first forming unit (12), and the die structure includes a first die member (32) configured to cooperate with the mold member (14) of the first forming unit (12) when the first forming unit (12) is in its second forward position, in order to form the central portion of the wire (52) into a V-shaped bridge portion. (Item 3) As a result of the first forming unit (12) being moved to its second forward position, the central portion of the wire (52) is pushed by the mold member (14) of the first forming unit (12) between and beyond the two supports (53, 53A), forcing the two opposing portions of the wire (52) to bend and form the two substantially parallel legs (H1'), thereby the two stationary supports (53, 53A) are positioned and configured to act as additional die members. The apparatus according to item 2, wherein the forward movement of the first forming unit (12) causes the formation of the V-shaped bridge portion (H1') and the formation of the two parallel legs (H1') of the two-dimensional semi-worked product (H'). (Item 4) The second forming unit (13) is A sliding structure (13A) that is movable along the first axis (X) on the base plate (11); The lateral extrusion member is in the form of two lateral arms (46) gripped by the slide structure (13A), and is movable transversely to the first axis (X) relative to the slide structure (13A); A wire engagement element (54) is held by the lateral arm (46) and is configured to engage the two legs (H1') of the two-dimensional semi-worked product (H') in the lateral direction from the outside; and The second forming unit (13) is configured to move from its third retracted position to its fourth forward position, resulting in lateral movement of the lateral arm (46), and when the second forming unit (13) is returned to its third retracted position, the cam means (46A, 45) causes the engaging element (54) to push the two legs (H1') of the two-dimensional semi-workpiece (H') laterally inward toward each other so that the two legs (H1') of the two-dimensional semi-workpiece (H') return to a position substantially parallel to each other. The apparatus described in item 1, having the following features. (Item 5) The apparatus according to item 4, wherein the two lateral arms (46) are rotatably mounted on a vertical axis (42) on the slide structure (13A) of the second forming unit (13), and the cam means includes a cam surface (46A) provided on the lateral arms (46) and configured to engage a cooperating member (45), such that the movement of the slide structure (13A) from the third retracted position to the fourth forward position causes the lateral arms (46) to rotate toward each other, and the wire engagement element (54) gripped by the lateral arms (46) pushes toward each other the two legs (H1') of the two-dimensional semi-worked product (H'). (Item 6) The apparatus according to item 4, wherein the wire engagement element is a freely rotatable roller (54) gripped by the lateral arm (46). (Item 7) The apparatus according to item 5, wherein the cooperating member is a freely rotatable roller (45) gripped by a stationary support, and a spring (43) is operably interposed between the rotating lateral arm (46) and the sliding structure (13A), respectively, biasing each of the rotating lateral arms (46) with respect to the respective cooperating roller (45). (Item 8) The apparatus according to item 7, wherein each cooperative roller (45) is adjustable in position along a direction perpendicular to the first axis (X). (Item 9) A method for forming a flat wire into the shape of a hairpin (H) having a general U-shape, for use in the manufacture of a motor stator, the method comprising: Step of installing the stationary base plate (11); In the step of holding a substantially straight wire along the horizontal support direction using a pair of stationary supports (53) provided on the base plate (11), the two supports (53) hold the wire at two positions spaced apart from each other; A first forming unit (12) is provided on the base plate (11) so as to be slidable along a first horizontal axis (X) perpendicular to the direction of horizontal wire support, and in the step of moving the first forming unit (12) from a first retracted position to a second forward position using an actuator (3), in the second forward position, the mold member (14) of the first forming unit (12) cooperates with a stationary die structure (31, 32, 53A) gripped by the base plate (11) to form the wire into a two-dimensional formed semi-workpiece (H') including a V-shaped bridge portion (H2') and two substantially parallel leg portions (H1'); A second forming unit (13) is provided on the base plate (11) so as to be slidable along the first horizontal axis (X), and an actuator (4) is used to move the second forming unit (13) from a third retracted position to a fourth forward position in the opposite direction to the movement of the first forming unit (12) from the first retracted position to the second forward position; The second forming unit (13) includes a lateral extrusion member (46) configured to compensate for any spring-back effect of the two legs (H1') and thereby slightly push the two legs (H1') of the two-dimensional formed semi-workpiece (H') laterally inward as the second forming unit (13) moves to its fourth forward position, such that the two legs remain substantially parallel to each other when the second forming unit (13) is returned to its third retracted position; and A third forming unit (21) is provided that is movable perpendicular to the base plate (11), and an actuator (5) is used to move the third forming unit (21) from an elevated position to a lowered position. In the lowered position, the mold member (22) of the third forming unit (21) cooperates with the stationary mold member (34) of the die structure (31, 32, 34, 53A) to bring the two-dimensional formed semi-workpiece (H') into a final three-dimensional shape (H). A method for providing this.
Claims
1. An apparatus for forming a flat wire having a flat cross-section into a hairpin shape having a general U-shape, which includes two substantially parallel legs connected by a bridge, for use in the manufacture of a motor stator, the apparatus is: Static base plate; A pair of wire restraint supports, provided on the aforementioned restraint base plate and configured to hold a substantially straight wire along the horizontal support direction by holding the wire at two spaced-apart positions; A first forming unit, slidably mounted on the stationary base plate along a first horizontal axis perpendicular to the horizontal support direction, and adapted to be moved by an actuator from a first retracted position to a second forward position; A stationary die structure, which is gripped by the stationary base plate and configured to cooperate with the mold member of the first forming unit as a result of the first forming unit moving from its first retracted position to its second forward position in order to form the wire into a two-dimensional formed semi-workpiece including a V-shaped bridge portion and two substantially parallel legs; A second forming unit, which is slidably mounted on the stationary base plate along the first horizontal axis and is adapted to be moved by an actuator from a third retracted position to a fourth forward position in the opposite direction to the direction of movement of the first forming unit from the first retracted position to the second forward position; A lateral extrusion member is configured such that the second forming unit compensates for any spring-back effect of the two legs, thereby slightly pushing the two legs laterally inward as a result of the second forming unit's movement to its fourth forward position, so that the two legs remain substantially parallel to each other when the second forming unit is returned to its third retracted position; and The third forming unit is movable perpendicular to the stationary base plate and is moved from an upward position to a downward position by an actuator, and in the downward position, the mold member of the third forming unit cooperates with the stationary mold member of the stationary die structure to bring the two-dimensional formed semi-workpiece into a final three-dimensional shape. A device equipped with the following features.
2. The apparatus according to claim 1, wherein the mold member of the first forming unit is the pointed front portion of the first forming unit, and the stationary die structure includes a first die member configured to cooperate with the mold member of the first forming unit when the first forming unit is in its second forward position in order to form the central portion of the wire into a V-shaped bridge portion.
3. As a result of the first forming unit being moved to its second forward position, the central portion of the wire is pushed between and beyond the two supports by the mold member of the first forming unit, forcing the two opposing portions of the wire to bend to form the two substantially parallel legs, thereby the two stationary supports are positioned and configured to act as additional die members. The apparatus according to claim 2, wherein the forward movement of the first forming unit causes the formation of the V-shaped bridge portion and the formation of the two parallel legs of the two-dimensional formed semi-workpiece.
4. The second forming unit is, A sliding structure that is movable along the first horizontal axis on the stationary base plate; The lateral extrusion member is in the shape of two lateral arms gripped by the slide structure and is movable transversely to the first horizontal axis relative to the slide structure; A wire engagement element, which is gripped by the lateral arm and configured to engage the two legs of the two-dimensionally formed semi-worked product laterally from the outside; and The second forming unit is configured to move from its third retracted position to its fourth forward position, resulting in lateral movement of the lateral arm, and when the second forming unit is returned to its third retracted position, the cam means causes the wire engaging element to push the two legs of the two-dimensional formed semi-workpiece laterally inward toward each other so that the two legs of the two-dimensional formed semi-workpiece return to a position substantially parallel to each other. The apparatus according to any one of claims 1 to 3, having the following features.
5. The apparatus according to claim 4, wherein the two lateral arms are rotatably mounted on a vertical axis on the slide structure of the second forming unit, and the cam means includes a cam surface provided on the lateral arms and configured to engage a cooperating member, such that when the slide structure moves from the third retracted position to the fourth forward position, the lateral arms rotate toward each other, and the wire engaging element gripped by the lateral arms pushes toward each other the two legs of the two-dimensional formed semi-workpiece.
6. The apparatus according to claim 4, wherein the wire engagement element is a freely rotatable roller gripped by the lateral arm.
7. The apparatus according to claim 5, wherein the cooperating member is a freely rotatable roller gripped by a stationary support, and a spring is operably interposed between each of the rotating lateral arms and the sliding structure, biasing each of the rotating lateral arms with respect to the respective cooperating roller.
8. The apparatus according to claim 7, wherein each cooperative roller is adjustable in position along a direction perpendicular to the first horizontal axis.
9. A method for forming a flat wire into a hairpin shape having a general U-shape, including two substantially parallel legs connected by a bridge portion, for use in the manufacture of a motor stator, the method is: The stage of installing a stationary base plate; In the step of holding a substantially straight wire along the horizontal support direction using a pair of stationary supports provided on the stationary base plate, the two supports hold the wire at two positions spaced apart from each other; A first forming unit is provided on the stationary base plate, slidably mounted along a first horizontal axis perpendicular to the horizontal support direction, and an actuator is used to move the first forming unit from a first retracted position to a second forward position. In the second forward position, the mold member of the first forming unit cooperates with a stationary die structure held by the stationary base plate to form the wire into a two-dimensional formed semi-workpiece including a V-shaped bridge portion and two substantially parallel legs; A second forming unit is provided on the stationary base plate so as to be slidable along the first horizontal axis, and an actuator is used to move the second forming unit from a third retracted position to a fourth forward position in the opposite direction to the direction of movement of the first forming unit from the first retracted position to the second forward position; The second forming unit includes a lateral extrusion member configured to compensate for any spring-back effect of the two legs, thereby slightly pushing the two legs laterally inward as the second forming unit moves to its fourth forward position, such that the two legs remain substantially parallel to each other when the second forming unit is returned to its third retracted position; and A third forming unit is provided that is movable perpendicular to the stationary base plate, and an actuator is used to move the third forming unit from an elevated position to a lowered position. In the lowered position, the mold member of the third forming unit cooperates with the stationary mold member of the stationary die structure to bring the two-dimensional formed semi-worked product into a final three-dimensional shape. A method for providing this.