DE102023211926A1 - Bending device for an elongated workpiece - Google Patents

Abstract

The present invention relates to a bending device (10) for an elongated workpiece (22), in particular a wire, comprising a first bending pin (12) with a first longitudinal central axis (14), and a second bending pin (18) with a second longitudinal central axis (20), wherein the second bending pin (18) is arranged substantially parallel to the first bending pin (12) and spaced therefrom, wherein the elongated workpiece (22) can be received between the first bending pin (12) and the second bending pin (18) and can be bent about the first bending pin (12) and/or the second bending pin (18), wherein the first bending pin (12) is rotatable about the first longitudinal central axis (14) and the second bending pin (18) is rotatable about the second longitudinal central axis (20). Furthermore, the present invention relates to a winding machine for a coil of an electric machine with such a bending device (10) and to a method for bending an elongated workpiece (22) with such a bending device (10) or such a winding machine.

Description

The invention relates to a bending device for an elongated workpiece, in particular a wire. Furthermore, the invention relates to a winding machine for a coil of an electric motor having such a bending device, as well as to a method for bending an elongated workpiece using such a bending device or such a winding machine.

Electrical machines for converting electrical energy into kinetic energy or for converting kinetic energy into electrical energy are used in a variety of ways.

For the production of individual components, such as stators or rotors, of these electrical machines, it is often necessary to form, separate, connect or otherwise process wires.

Hairpin processes, for example, are used for this purpose. In these processes, coil windings, particularly those of a stator, are formed from a large number of wire pieces, and the ends of the wire pieces are connected to one another. Metal wires without an insulating layer or metal wires partially/fully provided with an insulating layer are pre-bent into a desired shape. This is usually done with several bends (or bending processes) to create a desired shape for the coil or a section thereof. Since the components of electrical machines are usually designed in a ring or annular manner around a rotational axis of the electrical machine, the metal wires or coil windings often have to be adapted to the curvature of the corresponding component.

A device for producing a coil is known, for example, from DE 11 2010 000 029 T5 A bending tool can comprise an inner and an outer columnar edge pin, wherein the outer edge pin is pivotably mounted about a central axis of the inner edge pin. The pivoting of the outer edge pin causes a bending of a conductor arranged between the edge pins.

The disadvantage here is that the bending process leaves marks on the conductor. This applies to soft conductor materials, such as copper or aluminum conductors, or conductors coated with an insulating material, plastic, or enamel. Hard or brittle conductor materials or coatings, such as enamel, can crack or, under certain circumstances, break.

It is an object of the invention to provide a bending device for an elongated workpiece, in particular a wire, in order to at least partially eliminate the above-mentioned disadvantages.

This object is achieved according to the invention by the bending device for an elongated workpiece, in particular a wire, the winding machine for a coil of an electric motor with such a bending device, and the method for bending an elongated workpiece, in particular a wire, with such a bending device or such a bending machine. Advantageous embodiments and further developments of the invention are evident from the dependent patent claims.

The invention relates to a bending device for an elongated workpiece, in particular a wire, comprising a first bending pin with a first longitudinal central axis, and a second bending pin with a second longitudinal central axis, wherein the second bending pin is arranged substantially parallel to the first bending pin and spaced therefrom, wherein the elongated workpiece can be received between the first bending pin and the second bending pin and can be bent about the first bending pin and/or the second bending pin, wherein the first bending pin is rotatable about the first longitudinal central axis and the second bending pin is rotatable about the second longitudinal central axis.

The bending device may comprise a support, e.g., a plate, on which the bending pins are rotatably mounted. The bending device may enable two- or three-dimensional deformation of the elongated workpiece, in particular wire.

The bending pins can be made of a suitable material, e.g. steel, preferably tool steel. The bending pins are preferably rotationally symmetrical, preferably circular, around the respective longitudinal center axis. A cross-section along the respective longitudinal center axis can have different dimensions. For example, both bending pins can have a cylindrical shape with different diameters. A surface of the bending pins, which is intended to contact the workpiece, can be coated with a polymer material. By using the polymer material, any impressions that may occur on the workpiece during the bending process, in particular on a coating applied to the workpiece, can be reduced or avoided. One or more further pivot pins and/or one or more fixed bending pins can be provided and, if necessary, arranged on the carrier.

The elongated workpiece, e.g., a tube or a wire, in particular a wire, can be arranged with a slight clearance between the first bending pin and the second bending pin. Preferably, the elongated workpiece, in particular the wire, is arranged directly adjacent to the first bending pin and the second bending pin.

The elongated workpiece, e.g., a tube or a wire, in particular a wire, can have any cross-section, e.g., polygonal, elliptical, or circular, preferably circular. The metal of the wire can be an elemental metal, e.g., copper or aluminum, or an alloy, e.g., a copper-silver alloy.

Within the scope of the present invention, both bending pins are each arranged so as to be rotatable about their respective longitudinal central axes. It is assumed that during a bending process of the elongated workpiece located between the bending pins, the force acting on the workpiece surface can be distributed more evenly over a larger surface section of the workpiece. This makes it possible to reduce or avoid unwanted marks on the workpiece, in particular on a coating applied to the workpiece. Any deformation of the workpiece that may occur when forces are applied to the elongated workpiece can also be avoided. Furthermore, breakage of a comparatively hard or brittle coating, e.g. enamel, can be prevented. New materials, in particular soft, but also brittle or fragile materials, or material combinations can be used to manufacture the workpiece and/or its coating.

According to one embodiment, a distance between the first bending pin and the second bending pin is adjustable. For example, the first bending pin can be mounted in a through-opening enclosed by a carrier, e.g., a plate, and moved along said through-opening. The through-opening extends at an angle of <90°, preferably 0°C, to a straight line passing through the two bending pins. Alternatively, both bending pins can each be arranged so as to be movable relative to one another in a through-opening formed by a carrier. This allows the cross-sectional dimensions of various elongated workpieces, in particular metal wires, to be taken into account. This makes the bending device more versatile.

According to one embodiment, the first bending pin and the second bending pin are each rotatably mounted in a rolling bearing, preferably a needle bearing. Rolling bearings, especially needle bearings, are characterized by low friction and low wear. Maintenance of the bending device can thus be simplified and/or performed at longer intervals.

According to one embodiment, the bending device comprises a motor adapted to rotate the first bending pin and/or second bending pin. The shaft of the motor can, for example, bear against the first and/or second longitudinal center axis or be connected to the respective longitudinal center axis. Preferably, both bending pins each have a motor. The use of a motor enables the conveyance of the elongated workpiece, in particular wire, such that a further position can be subjected to a bending process. Furthermore, the force acting on the elongated workpiece, in particular wire, and thus the bending process, can be precisely controlled.

According to one embodiment, the first and/or second bending pin is rotationally symmetrical about its respective longitudinal center axis. This allows for a uniform and reproducible deformation of the elongated workpiece, in particular the wire.

According to one embodiment, a cross-section of the first and/or second bending pin is polygonal, elliptical, or circular. Polygonal cross-sections preferably comprise polygons with corresponding edge lengths, more preferably with 6 or more corners, for example with 12 or more corners, further, for example, with 18 or more corners. The bending device is preferably designed in a modular manner such that the bending pins can be replaced by other bending pins. In this case, a set of bending pins can be provided that differs in geometry, i.e., cross-sectional shape, and/or cross-sectional dimensions. For example, the cross-sectional shape of both bending pins can be circular, wherein a diameter of the two cross sections can be the same or different.

According to one embodiment, the bending device comprises a support on which the first bending pin and the second bending pin are rotatably mounted. The support can, for example, be designed as a plate on which the two bending pins are arranged. The support can also be configured to secure the elongated workpiece, in particular the wire. For example, at least one end of the elongated workpiece, in particular the wire, can be attached to the support.

According to one embodiment, the first bending pin is arranged around the second longitudinal central axis and/or the second bending pin is arranged around the first longitudinal central axis arranged rotatably. The carrier can, for example, comprise a first plate with a first bending pin and a second plate with a second bending pin. The two plates are arranged parallel and spaced from one another such that the elongated workpiece, in particular wire, can be received between the plates and between the bending pins. In this case, the carrier and the bending pins can surround or constrict the elongated workpiece, in particular the wire, such that the elongated workpiece, in particular the wire, cannot be forced out of a space between the bending pins during a bending process. Thus, the carrier and bending pins can serve to fix the elongated workpiece, in particular the wire. Alternatively, the carrier can comprise an inner circular plate and a coplanar annular plate, wherein the annular plate is arranged adjacent to the inner circular plate and can be rotated relative to the inner circular plate. The first bending pin can be arranged on a center point of the inner circular plate and the second bending pin can be arranged on the annular plate. By rotating the inner circular plate relative to the annular plate, an adjustable force for deforming the elongated workpiece, in particular wire, can be provided. Furthermore, a through-opening present in a radius section can be formed on the inner circular plate and/or the annular plate, in which through-opening the first and/or second bending pin is arranged to be movable in the radial direction. This allows the distance between the two bending pins to be adjusted. Alternatively, the carrier can comprise a first circular plate with a first bending pin arranged at a center thereof and a second circular plate with a second bending pin arranged at a center thereof. The two circular plates are arranged parallel and spaced from one another such that the elongated workpiece, in particular wire, can be received between the circular plates and between the bending pins. Furthermore, a through-opening present in a radius section can be formed on the first circular plate and/or the second circular plate, in which through-opening the first and/or second bending pin is arranged to be movable in the radial direction. The two circular plates can be arranged one above the other, with the bending pins between them, such that the peripheral edge of one circular plate intersects the longitudinal center axis of the other circular plate. This allows for a compact arrangement of the bending device. Simplified access to both bearings, e.g., the rolling bearings of the bending pins, and any additional components present, e.g., a motor for rotating a bending pin, can be provided. If a bending pin is slidably mounted in a through-hole, the spacing between the bending pins can be easily adjusted.

According to one embodiment, the wire has an electrically insulating sheath. The electrically insulating sheath or insulation layer can completely or partially surround the wire. For example, a wire provided with an insulation layer can be stripped at its ends. The insulation layer can be present, for example, as an electrically non-conductive plastic layer, e.g., as varnish or enamel. The wire can be made of metal, for example, as an elemental metal, in particular copper or aluminum, or as an alloy, e.g., a copper-silver alloy. During the bending process with the present bending device, the electrically insulating sheath is not or only slightly impaired or damaged. Disturbing marks on the insulating sheath can be at least partially avoided.

According to one embodiment, a winding machine for a coil of an electric motor is provided with a bending device according to the invention. Such coil winding machines or wire winding machines or winding systems are known in the prior art. The winding machine is preferably adapted for the production of plug-in coils, in particular hairpins, for stators of electric motors, in particular traction motors for electric vehicles, or generators. In hairpin technology, for example, plug-in coils made of U-shaped, lacquered flat copper wires are inserted into the stator slots of the laminated core. The bending device according to the invention is particularly preferred for the production of hairpins with a U-geometry due to the use of lacquered copper wires, in which, due to the use of the bending device according to the invention, no or only minor imprints remain on the lacquer of the copper wires. Damage to the lacquered copper wires during the bending process can thus be avoided.

According to one embodiment, a method for bending an elongate workpiece, in particular a wire, is provided using a bending device according to the invention. The method comprises: providing an elongate workpiece between the first bending pin and the second bending pin, and applying a force to the elongate workpiece in a direction oblique to a direction of travel of the elongate workpiece and in the direction of the first longitudinal center axis and/or the second longitudinal center axis. The force acting on the elongate workpiece thus acts at least partially in such a way that the elongate workpiece is pressed against one of the bending pins and bent around it. The rotatable mounting of the first bending pin about the first longitudinal center axis and of the second bending pin about the second longitudinal center axis enables the production of bent workpieces, in particular bent wires, with an intact coating, particularly for the production of hairpins with a U-geometry.

A substantially parallel arrangement of the first and second bending pins may include an oblique alignment of the first and second longitudinal center axes relative to one another, for example, at an angle of less than 45°, for example, less than 30°, less than 20°, less than 15°, less than 10°, less than 5°, or less than 1°. Preferably, the first and second longitudinal center axes are aligned parallel.

A small amount of play with which the elongated workpiece, e.g. a tube or a wire, in particular a wire, can be arranged between the first bending pin and the second bending pin, refers to a play of less than 50%, e.g. less than 25%, less than 10%, or less than 5%, of a cross-sectional dimension of the elongated workpiece, e.g. a tube or a wire, in particular a wire. Therefore, A = S + Q, where A is the distance between the two bending pins, S is the play or the free space between the elongated workpiece, e.g. a tube or a wire, in particular a wire, and the bending pins, and Q is the cross-sectional dimension of the elongated workpiece, e.g. a tube or a wire, in particular a wire. Preferably, there is no play and the elongated workpiece, e.g. a tube or a wire, in particular a wire, is adjacent to the two bending pins.

The invention is explained below by way of example with reference to embodiments shown in the figures.

• 1 zeigt eine schematische Darstellung einer Biegevorrichtung gemäß einer ersten Ausführungsform,
• 2 zeigt eine schematische Seitenansicht einer Biegevorrichtung gemäß einer weiteren Ausführungsform, und
• 3 zeigt eine schematische Draufsicht auf die Biegevorrichtung der 2.

They show:

• 1 shows a schematic representation of a bending device according to a first embodiment,
• 2 shows a schematic side view of a bending device according to another embodiment, and
• 3 shows a schematic plan view of the bending device of the 2 .

Identical objects, functional units, and comparable components are designated by the same reference symbols throughout the figures. These objects, functional units, and comparable components are identical in terms of their technical features, unless explicitly or implicitly stated otherwise in the description.

1 shows a schematic representation of a bending device 10 according to a first embodiment. The bending device 10 has a first bending pin 12 and a second bending pin 18. In the present case, the bending pins 12, 18 have a cylindrical shape with identical dimensions and are made of conventional tool steel. The first bending pin 12 is rotatably received in a first bending unit 52 with a first axial bearing 42 and a first needle bearing 32 along a first longitudinal center axis 14 in a direction of rotation 16. Accordingly, the second bending pin 18 is rotatably received in a second bending unit 58 with a second axial bearing 48 and a second needle bearing 38 along a second longitudinal center axis 20 in the direction of rotation 16. The bending device 10 further comprises a support 60 configured as a first axial fixation 78 and a second axial fixation 68, via which the bending device 10 is accommodated, for example, in a winding machine (not shown) for a coil of an electric motor. A first axial fixation 78 and a second axial fixation 68 of the support 60 are arranged parallel and spaced from one another such that an elongated workpiece 22, configured in this case as a wire, can be accommodated between the first and second axial fixations 78, 68 and between the bending pins 12, 18.

The 1 It can also be seen that an elongated workpiece 22, designed as a copper wire, is present between the parallel-aligned bending pins 12, 18. When a force (not shown) is applied to the elongated workpiece 22, it can now be bent around one or both bending pins 12, 18. Due to the rotatable design of the bending pins 12, 18 about the respective longitudinal center axes 14, 20, the bending pins 12, 18 can rotate when force is applied, thereby preventing damage to the elongated workpiece 22, for example an imprint on a material that is softer than the material of the bending pins 12, 18. The arrangement of the bending pins 12, 18 and axial fixations 78, 68 around the elongated workpiece 22 also enables its partial or complete fixation in the bending device 10 during the bending process.

With reference to 2 A schematic side view of a bending device 10 according to a further embodiment is shown. In the present case, two bending pins 12, 18 are rotatably arranged on a carrier 60 with an inner circular plate 62 and a circular ring plate 64. Thus, The first bending pin 12 is arranged on an inner circular plate 62 so as to be rotatable about the first longitudinal central axis 14 in the direction of rotation 16. A second bending pin 18 is arranged on an annular plate 64 at a distance from and parallel to the first bending pin 12 and is arranged so as to be rotatable about the second longitudinal central axis 14 in the direction of rotation 16. The inner circular plate 62 and the annular plate 64 are arranged coplanarly such that the inner circular plate 62 and the annular plate 64 can be rotated about a common axis of rotation 66 in the direction of rotation 16. In the present case, the inner circular plate 62 and the annular plate 64 can be rotated relative to one another by a motor (not shown), whereby an elongated workpiece 22, designed as a wire, can be received between the bending pins 12, 18 and the carrier 60 and bent by corresponding rotation of the inner circular plate 62 relative to the annular plate 64.

With further reference to 3 is a schematic plan view of the bending device 10 of the 2 shown. 3 It can be seen that the inner circular plate 62 has a radially aligned through-opening 70 along which the first bending pin 12 can be displaced along a linear displacement path 72 in the direction of the common axis of rotation 66 or the circular ring plate 64 in such a way that the elongated workpiece 22, designed as a wire, can be received precisely, i.e. without play, between the bending pins 12, 18. By rotating the inner circular plate 62 with respect to the circular ring plate 64, the elongated workpiece 22, designed as a wire, received precisely between the bending pins 12, 18, is pressed against the two bending pins 12, 18 at the same time. The two bending pins 12, 18 can be rotated independently of each other about their respective longitudinal center axes 14, 20, whereby an imprint caused by the bending pins 12, 18 on the elongated workpiece 22 designed as a wire can be at least partially avoided.

Reference symbol

10

Bending device

12

first bending pin

14

first longitudinal center axis

16

Direction of rotation

18

second bending pin

20

second longitudinal center axis

22

elongated workpiece

32

first needle bearing

38

second needle bearing

42

first axial bearing

48

second axial bearing

52

first bending unit

58

second bending unit

60

carrier

62

inner circle plate

64

circular ring plate

66

axis of rotation

68

second axial fixation

78

first axial fixation

70

passage opening

72

linear displacement

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 11 2010 000 029 T5 [0005]

Claims (11)

Bending device (10) for an elongated workpiece (22), in particular a wire, comprising a first bending pin (12) with a first longitudinal central axis (14) and a second bending pin (18) with a second longitudinal central axis (20), wherein the second bending pin (18) is arranged substantially parallel to the first bending pin (12) and spaced therefrom, wherein the elongated workpiece (22) can be received between the first bending pin (12) and the second bending pin (18) and can be bent about the first bending pin (12) and/or the second bending pin (18), wherein the first bending pin (12) is rotatable about the first longitudinal central axis (14) and the second bending pin (18) is rotatable about the second longitudinal central axis (20). Bending device (10) according to Claim 1 , wherein a distance between the first bending pin (12) and the second bending pin (18) is adjustable. Bending device (10) according to one of the preceding claims, wherein the first bending pin (12) and the second bending pin (18) are each rotatably mounted in a rolling bearing, preferably a needle bearing (32, 38). Bending device (10) according to one of the preceding claims, comprising a motor adapted to rotate the first bending pin (12) and/or second bending pin (18). Bending device (10) according to one of the preceding claims, wherein the first and/or second bending pin (12, 18) is rotationally symmetrical about its respective longitudinal center axis (14, 20). Bending device (10) according to one of the preceding claims, wherein a cross section of the first and/or second bending pin (12, 18) is polygonal, elliptical or circular. Bending device (10) according to one of the preceding claims, comprising a carrier (60) on which the first bending pin (12, 18) and the second bending pin (12, 18) are rotatably arranged. Bending device (10) according to one of the preceding claims, wherein the first bending pin (12) is arranged to be rotatable about the second longitudinal central axis (20) and/or the second bending pin (18) is arranged to be rotatable about the first longitudinal central axis (14). Bending device (10) according to one of the preceding claims, wherein the wire has an electrically insulating sheath. Winding machine for a coil of an electric machine with a bending device (10) according to one of the preceding claims. Method for bending an elongated workpiece (22), in particular a wire, with a bending device (10) according to one of the Claims 1 - 9 or a bending machine according to Claim 10 , comprising: providing an elongated workpiece (22) between the first bending pin (12) and the second bending pin (18), and applying a force to the elongated workpiece (22) in a direction oblique to a direction of travel of the elongated workpiece (22) in the direction of the first longitudinal center axis (14) and/or the second longitudinal center axis (20).

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