Apparatus for bending flat wire into shape
The apparatus addresses the challenge of high-speed, precise wire bending by using an anti-warping element and cam device to maintain the wire in the bending plane, achieving efficient hairpin formation for motor stators.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- COMAU SPA
- Filing Date
- 2025-08-04
- Publication Date
- 2026-05-21
AI Technical Summary
Existing wire bending apparatuses for forming hairpins in motor stators face challenges in achieving high production speeds with precise and reliable bending operations while preventing warping of the wire out of the bending plane.
The apparatus incorporates an anti-warping element with an enlarged head, a slide member, and a cam device to prevent warping, along with a bending shaft and a wire support and feeding system, including a wire placement table and a handling robot with a gripper for precise wire handling.
Enables high-speed, precise, and reliable bending of wires into hairpin shapes, ensuring the wire remains within the bending plane during the process.
Smart Images
Figure IB2025057897_21052026_PF_FP_ABST
Abstract
Description
[0001] “APPARATUS FOR BENDING FLAT WIRE INTO SHAPE” TECHNICAL FIELD
[0002] The present invention relates to an apparatus for bending a wire, particularly for shaping a wire into the form of a hairpin, for use in the manufacture of a motor stator.
[0003] The invention relates, in particular, to an apparatus of the type comprising:
[0004] - a wire bending device, and
[0005] - a wire supporting and feeding device, for supporting and feeding a wire portion to said wire bending device,
[0006] - wherein the wire bending device includes:
[0007] - a bending shaft having a shaft axis,
[0008] - a motor adapted to drive the bending shaft in rotation around the shaft axis, and
[0009] - a bending element, which is carried by the bending shaft at a distance from the shaft axis, in such a way that a rotation of the bending shaft causes the bending element to move around the shaft axis and engage a wire portion which is supported on an upper end surfaced of the bending shaft so as to bend the wire portion around the bending shaft.
[0010] BACKGROUND OF THE INVENTION
[0011] An apparatus of the above-indicated type is known, for example, from document DE 102018 106980 A1.
[0012] Hairpin technology is a winding technology applied in the field of electric motors, based on solid, flat copper bars configured for being inserted into a stator stack. These copper bars, so-called “hairpins”, consist of enamelled copper wire bent into a U-shape.
[0013] The prior solutions, which are known in the field of apparatus for bending a wire into the form of a hairpin, have proved to be not fully satisfactory from the point of view of enabling very high productions with high production speeds, while ensuring a reliable and precise bending operation.
[0014] There is therefore a need of further improvements in this field. There is, in particular, the need of preventing a warping of the wire portion out of the bending plane, during the bending operation.
[0015] SUMMARY OF THE INVENTION
[0016] It is therefore an object of the present invention to provide an apparatus for bending a wire, particularly for shaping a flat wire into the form of a hairpin, for use in the manufacture of a motor stator, which enables very high production speeds, while ensuring a precise and reliable bending operation.
[0017] It is in particular an object of the invention to provide an apparatus of the above-indicated type in which a warping of the wire portion out of the bending plane, during the bending operation, is prevented, with simple and reliable means.,
[0018] A further object is to provide an apparatus of the above-indicated type which has a relatively simple and inexpensive construction.
[0019] In view of achieving these objects, the invention provides an apparatus having the features indicated at the beginning of this description and further characterised in that:
[0020] - the apparatus comprises an anti-warping element with an enlarged head, configured to project above said wire portion, so as to prevent warping of the wire portion out of a bending plane, during the bending operation, - the anti-warping element is carried by a slide member which is mounted on the bending shaft so that the slide member can be driven in rotation along with the bending shaft, while being able to slide relative to the bending shaft along a sliding direction orthogonal to the shaft axis, and - the apparatus further comprises a cam device, disposed between a stationary support structure and said slide member, said cam device includes a bracket carried by said stationary support structure and a cam follower carried by said slide member and guided within said shaped slot, said cam device being configured so that the slide member is caused to move along said sliding direction, while being driven in rotation along with the bending shaft,
[0021] so that the anti-warping element moves relative to the wire portion during the bending operation, to a position in which the enlarged head of the anti-warping element projects above the wire portion.
[0022] The slide member is a plate orthogonal to said bending shaft and having a main portion and two side arms which extend from the main portion, which arms are spaced apart from each other and slidably engaged within opposite side grooves of the bending shaft, so that the two arms are driven in rotation by the bending shaft while being able to slide relative to the bending shaft along said sliding direction orthogonal to the shaft axis.
[0023] The bending shaft has an upper flat end surface configured to support the wire portion during the bending operation, and a central pin projecting from the upper end surface, around which the wire portion can be bent.
[0024] The bending element, preferably a roller, is carried by the bending shaft through a support projecting from the bending shaft and adjustable in position relative to the bending shaft, so that the distance of the bending element from the shaft axis can be adjusted.
[0025] The wire support and feeding device includes a wire placement table, including an upwardly-facing groove for receiving and supporting a wire portion, and a wire feeding device including at least one jaw for clamping the wire portion on the wire placement table and for advancing the wire portion to a position for being bent by said wire bending device.
[0026] The apparatus of the present invention also includes a handling device with a robot provided with a gripper including a plurality of suction pads for picking-up a wire portion from a wire stack mechanism and for placing the picked-up wire portion on said wire placement table
[0027] BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Further features and advantages of the invention will become clearly apparent from the following description, given purely by way of example, with reference to the annexed drawings, in which:
[0029] figure 1 is a perspective view of an apparatus according to the invention, figure 2 shows subsequent configurations which can be imparted to a wire portion by means of the apparatus according to the invention, starting from a straight configuration and ending with a hairpin shape,
[0030] figure 3 is a perspective view of a wire stack mechanism forming part of the apparatus according to the invention,
[0031] figure 4 is a further perspective view from below of the stack mechanism of figure 3,
[0032] figure 5 is a perspective view of a handling robot used in the apparatus according to the invention,
[0033] figure 6 is a perspective view of a gripper used by the robot of figure 5, figure 7 is a perspective view of a wire placement table according to the invention,
[0034] figure 8 is perspective view in cross-section of a detail of the wire placement table of figures 7, showing a jaw for clamping a wire portion, figure 9 is a plan view of the wire placement table and the wire bending device in the condition before starting the bending operation,
[0035] figure 10 is a perspective view at an enlarged scale of the wire bending device in the condition of figure 9,
[0036] figure 11 is a plan view similar to figure 9, in a condition after the bending operation,
[0037] figure 12 is a perspective view at an enlarged scale of the bending device in the condition of figure 11 ,
[0038] figures 13 and 14 are two additional perspective views showing the bending device in the condition after the bending operation,
[0039] figure 15 is a further perspective view of the wire bending device, figures 16 and 17 are perspective views showing, at an enlarged scale, some details of the wire bending device,
[0040] figures 18A, 18B, 18C, and 18D are plan views at an enlarged scale of the wire bending device in different stages of the bending operation, and figure 19 is a further perspective view of the wire bending device according to the invention.
[0041] DETAILED DESCRIPTION
[0042] With reference to figure 1 of at annexed drawings, numeral 1 generally designates an apparatus according to the invention, for bending a flat copper wire in order to shape the wire into the form of a hairpin, to be used in the manufacture of a motor stator.
[0043] Apparatus 1 comprises a support platform 2 on which there are mounted a wire stack mechanism 3, a wire placement table 4, a wire bending device 5 and a handling robot 6. In the illustrated example, the handling robot 6 is in the form of a Scara-type robot, provided with a gripper 7 including an aligned arrangement of suction pads 7A. It is to be noted that the handling robot 6 illustrated in the annexed drawings, is hereby shown only by way of example. Any other type of handling device and handling gripper can be used, within the spirit of the present invention.
[0044] Robot 6 is configurated for picking-up one wire portion W at a time from the wire stack mechanism 3 and for placing the picked-up wire portion W on the wire placement table 4, which is provided with wire support and feeding means, for supporting and feeding the wire portion W to a position in which it is bent by the wire bending device 5.
[0045] Figure 2 shows the subsequent stages of the shaping operation which is performed to impart a hairpin shape to an originally straight wire portion W.
[0046] Figure 2A shows the wire portion W in the original straight configuration. Figure 2B shows the wire portion W after a first bending operation at a point W1 of the wire portion W. After this first bending operation, which is performed by the wire bending device 5, the wire portion is caused to advance with respect to the bending device 5 so that a second bending operation can be performed at a bending point W2, as shown in figure 2C. After the second bending operation, the wire portion is caused to further advance relative to the wire bending device 5, whereupon the bending device 5 is used to perform a third bending operation at point W3, as shown in figure 2D.
[0047] As clearly apparent from the foregoing, the bending device 5 is used to perform each of the three bending operations on the wire portion W. As also clearly apparent from the foregoing, the apparatus according to the invention can be used to perform a bidimensional bending operation on the wire portion W. Further 3D shaping operations on the wire portion W, in which the hairpin is deformed out of the general plane of its original bidimensional shape, are to be performed with other means, which do not form part of the present invention.
[0048] With reference to figure 3, the wire stack mechanism 3 includes a support structure 3A carrying a rack with parallel arrangements of aligned holders 3B for receiving a number of wire portions W. The holders 3B are carried by a plate 3C which is slidably mounted on linear guides 3D (see also figure 4) along a direction orthogonal to the longitudinal direction of the wire portions W received on the wire stack mechanism 3. Positioning screws 3E, carried by stationary brackets 3F, are used for positioning plate 3C on the support structure 3A along the direction of the guides 3D.
[0049] With reference to figure 4, each wire receiving position on the wire stack mechanism 3 is provided with a sensor 3G of any known type, for detecting whether the associated seat is occupied or not.
[0050] Figures 5, 6 show the handling robot 6 and the associated gripper 7, which are used in the illustrated embodiment. Gripper 7 has a support structure carrying a line of suction pads 7A which can be put in communication through a manifold 7B with a vacuum source (not shown) in any known manner. Vacuum can be communicated to the suction pads 7A when the gripper 7 must pick-up a wire portion W from the wire stack mechanism 3, while this communication is closed when the gripper must deposit a picked-up wire portion on the wire placement table 4. The support structure of gripper 7 is provided with a flange for releasable connection to the robot end-effector (see figure 5).
[0051] With reference to figures 7-9, the wire placement table 4 includes a support structure 4A carrying a linear guide 4B on which a wire clamping and feeding device 4C is slidably mounted. The wire clamping and feeding device 4C includes at least one jaw 4D configured for clamping a wire portion W, which has been received on an upwardly-facing groove 4E formed in a plate 4F rigidly connected to the support structure 4A. A motor-and-reducer unit 4G is carried by the support structure 4A and is configured to drive a back-and-forth movement of the wire feeding device 4C. Each time that a wire portion W is received on the groove 4E of the wire placement table 4, the wire feeding device 4C clamps the wire portion with the aid of the jaw 4D and causes the wire portion to advance to a position in which the wire portion can be bent by the bending device 5. During the bending operation, the groove 4E within which the wire portion is held, prevents a lateral movement of the wire upstream of the bending point.
[0052] Figures 9, 11 show a plan view of the wire placement table 4 and the wire bending device 5 before and after a bending operation.
[0053] The structure and operation of the bending device 5 will be described hereinafter with reference to figures 9-19.
[0054] The wire bending device 5 includes a wire bending shaft 8, having an axis 8A. In this example, axis 8A is vertical. The bending shaft 8 can be driven in rotation around its axis 8A by an electric motor M (figure 13) through a reducer R. Motor M and reducer R are rigidly carried by a stationary support structure 9.
[0055] In this example, the bending shaft 8 has an upper flat end surface 8B (see in particular figure 16) configured to support the wire portion W in the region of the bending point, during the bending operation. A central pin 80 projects from the upper end surface 8B, so that the wire portion W can be bent around the central pin 80 (see, in particular, figures 10, 12).
[0056] The bending shaft 8 is provided with a bending element 15, which in this example is in the form of a freely rotatable roller, carried by a support 15A (figure 17) projecting from a cavity 81 (figure 16) of the bending shaft 8. Support 15A is radially adjustable in position relative to the bending shaft, so that the distance of the bending element (15) from the shaft axis (8A) can be adjusted.
[0057] During the bending operation, rotation of the bending shaft 8 causes the bending element 15 to perform a circular path around the bending axis 8A, so as to engage the wire portion W and bend the wire portion around the central pin 80 of the bending shaft. During the bending operation, a rear part of the wire portion W is still held within groove 4E of the wire placement table 4 by jaw 4D, so that it is prevented from moving.
[0058] With reference to figure 16, a slide member 10 is mounted on the bending shaft 8 so as to be driven in rotation along with the bending shaft 8 while being able to slide relative to the bending shaft along a direction 10A orthogonal to the shaft axis 8A.
[0059] In the illustrated example, the slide member 10 is in the form of a plate having a main portion 10B (see figure 16) and two parallel arms 10C which extend from the main portion 10B and are spaced apart from each other. The two parallel arms 10C of the slide member 10 are slidably engaged within two opposite side grooves 8C of the bending shaft 8 so as to be slidable relative to shaft 8 along direction 10A, while being driven in rotation along with the bending shaft 8.
[0060] Again, with reference in particular to figure 16, on the slide member 10 there is mounted an anti-warping element 11 which is in the form of a T-shaped pin parallel to the shaft axis 8A and located at a distance from this axis. The T-shaped pin 11 has an upper enlarged head 11A, which is configured to engage from above the wire portion W during the bending operation (see figure 12), so as to prevent warping of the wire portion W out of a bending plane during the bending operation.
[0061] The apparatus according to the invention further comprises a cam device disposed between the stationary support structure 9 and the slide member 10. The cam device is configured such that the slide member 10 is caused to perform a given sliding movement along the sliding direction 10A while being driven in rotation along with the bending shaft 8.
[0062] In the illustrated embodiment, the cam device includes a bracket 12 carried by the stationary support structure 9 and having a shaped slot 13 (see figure 12) in which a cam follower 14, carried by the slide member 10, is guided (see also figure 16). In the example of the present invention, the cam follower 14 is a freely rotatable roller carried by the slide member 10.
[0063] The shaped slot 13 of the bracket 12 has a curved profile which is so configured as to impart a given sliding movement to the slide member 10 while the slide member 10 is driven in rotation along with the bending shaft 8.
[0064] As a result of this arrangement, the anti-warping element 11 moves relative to the wire portion W during the bending operation, to a position in which the enlarged head 11A of the anti-warping element 11 projects above the wire portion 11 , thus preventing warping of the wire portion.
[0065] Figures 18A-18D show the different stages of the bending operation in a plan view. It can be seen that in the initial condition of figure 18A, the head 11 A is not located above the wire portion W, while in the subsequent stages, the head 11 A moves relative to the wire portion W, so that in the last part of the bending operation (figures 18C and 18D) the head 11A is partially superimposed on the wire portion W.
[0066] Due to the above-described structure and operation, the bending device 5 of the apparatus according to the invention is able to perform a precise and reliable bending operation in order to obtain a required shape of the wire portion, while enabling very high production speeds.
[0067] The above-described operation, in connection with a single bending operation, can be repeated for performing the various bending operations at points W2, W3 of the wire portion, as illustrated in figure 2, so as to finally obtain the required bidimensional hairpin shape.
[0068] Naturally, while the principle of the invention remains the same, the details of construction and the embodiments may widely vary with respect to what has been described in the foregoing, without departing from the scope of the present invention, as defined in the appended claims.
Claims
CLAIMS1. An apparatus for bending a wire (W), for shaping the wire into the form of a hairpin in the manufacture of a motor stator, the apparatus comprising:- a wire bending device (5), and- a wire supporting and feeding device (4), for supporting and feeding a wire portion (W), to said wire bending device (5),- wherein the wire bending device (5) includes:- a bending shaft (8), having a shaft axis (8A),- a rotation motor (M) adapted to drive the bending shaft (8) in rotation around the shaft axis (8A),- a bending element (15) which is carried by the bending shaft (8) at a distance from the shaft axis (8A), in such a way that a rotation of the bending shaft (8) causes the bending element (15) to move around the shaft axis (8A), and engage a wire portion (W), which is supported on an upper end surface of the bending shaft (8) so as to bend the wire portion (W) around said bending shaft (8),said apparatus being characterised in that:- the apparatus comprises an anti-warping element (11) with an enlarged head (11 A), configured to project above said wire portion (W), so as to prevent warping of the wire portion (W) out of a bending plane, during the bending operation,- the anti-warping element is carried by a slide member (10) which is mounted on the bending shaft (8) so that the slide member (10) can be driven in rotation along with the bending shaft (8) while being able to slide relative to the bending shaft (8) along a sliding direction (10A) orthogonal to the shaft axis (8A), and- the apparatus further comprises a cam device, disposed between a stationary support structure (9) and said slide member (10), said cam device (13, 14) being configured so that the slide member (10) is caused to move along said sliding direction (10A) while being driven in rotation along with the bending shaft (8),so that the anti-warping element (11 ) moves relative to the wire portion (W) during the bending operation, to a position in which the enlarged head(11 A) of the anti-warping element (11 ) projects above the wire portion (11 ).
2. The apparatus of claim 1 , characterized in that said cam device includes a bracket (12), carried by said stationary support structure (9), said bracket (12) having a shaped slot (13), and a cam follower (14), carried by said slide member (10) and guided within said shaped slot (13).
3. The apparatus of claim 1 or claim 2, characterized in that the slide member (10) is a plate orthogonal to said bending shaft (8) having a main portion (10B), and two side arms (10C), which extend from the main portion (10B), which arms (10C) are spaced apart from each other and are slidably engaged within opposite side grooves of the bending shaft (8), so that the two arms (10C) can be driven in rotation by the bending shaft (8) while being able to slide relative to the bending shaft (8) along said sliding direction (10A) orthogonal to the shaft axis (8A).
4. The apparatus of claim 1 , characterized in that said anti-warping element (11 ) is a T-shaped pin.
5. The apparatus of claim 1 , characterized in that said bending shaft (8) has an upper flat end surface (8B) configured to support the wire portion (W) during the bending operation, and a central pin (80) projecting from the upper end surface (8B), around which the wire portion (W) can be bent.
6. The apparatus of claim 1 , characterized in that the bending element (15) is carried by the bending shaft (8) through a support (15A) projecting from the bending shaft (8) and adjustable in position relative to the bending shaft, so that the distance of the bending element (15) from the shaft axis (8A) can be adjusted.
7. The apparatus of claim 1 , characterized in that said wire support and feeding device includes a wire placement table (4) with an upwardly facing groove (4E) for receiving and supporting a wire portion (4), and a wire feeding device (4C) including at least one jaw (4D) for clamping the wire portion (W) on the wire placement table (4) and for advancing the wire portion (W) to a position for being bent by said wire bending device (5).
8. The apparatus of claim 7, characterized in that it includes a handling device (6) for picking-up a wire portion (W) from a wire stack mechanism (3) and for placing the picked-up wire portion (W) on said wire placement table (4).
9. The apparatus of claim 8, characterized in that said handling deviceis a robot (6) provided with a gripper (7) including a plurality of suction pads (7A).