CONTACT ELEMENT FOR ELECTRICAL CONTACTING OF A WINDING WIRE OF A STATOR OF AN ELECTRIC MOTOR

Description

[0001] The invention relates to a contact element for electrically contacting at least one winding wire of a stator of an electric motor.

[0002] Electric motors typically have at least one stator coil, which is created by winding a winding wire around a stator core. The winding wire must be electrically connected to control the stator coil during operation of the electric motor. Appropriate contact elements are provided for this purpose, enabling reliable and simple external electrical contact of the winding wire.

[0003] Such contact elements for electrically contacting a winding wire are known, for example, from DE 10 2013 105 571 A1 and DE 10 2011 120 985 A1.

[0004] DE 10 2013 105 571 A1 proposes a contact element with a planar base. On a first side of the base, two legs extending perpendicular to the plane of the base are arranged for attaching the contact element to a stator. On a second side opposite the first side, a contact lug extending perpendicular to the plane of the base is arranged for external electrical contacting of the contact element. On the second side of the base, two hook-shaped retaining devices are also arranged for receiving and electrically contacting a winding wire. The contact element is manufactured by forming a stamped blank.

[0005] DE 10 2011 120 985 A1 proposes a contact element comprising a contact lug for external electrical contacting of the contact element and a holding device for receiving and electrically contacting a winding wire. The contact lug is planar and extends substantially along a longitudinal axis. The holding device is arranged on a transverse side of the contact lug and has a three-dimensional shape with multiple bends.

[0006] The proposed contact elements must be attached to the stator body after it has been wound, as otherwise they would obstruct the winding process. The proposed contact elements have a complex design and require elaborate manufacturing with several forming steps. Furthermore, the proposed contact elements require a significant amount of space on the stator.

[0007] Further constructive designs of contact elements for the electrical contacting of a winding wire are described in DE2924906 A1, US 2017 / 01110925 A1, DE 10 2015 216 698 A1 and EP 2 698 902 A2. However, these contact elements are also complex in structure and require elaborate manufacturing with several forming steps.

[0008] The objective is therefore to create a simple and compact contact element for the reliable electrical contacting of at least one winding wire of a stator of an electric motor. This objective is achieved by a contact element for the electrical contacting of at least one winding wire of a stator of an electric motor with the features of main claim 1. Advantageous embodiments of the contact element according to the invention are described in the dependent claims.

[0009] The contact element according to the invention for electrically contacting at least one winding wire of a stator of an electric motor is essentially planar and has three successive sections along a longitudinal axis that runs through the center of a contacting section: a mounting section for attaching the contact element to a stator, a receiving section for receiving and electrically contacting the winding wire, and the contacting section for electrically connecting the contact element to motor electronics. The receiving section of the contact element has a base section extending along the longitudinal axis, which is narrower than the contacting section.A holding device is arranged laterally on the base section. This device is designed to hold the winding wire and has a leg extending longitudinally away from the mounting section. During assembly of the electric motor, the stator winding wire is positioned in the holding device. By reshaping the leg of the holding device, a reliable electrical contact is created between the contact element and the winding wire. Additionally, the leg can be welded to the winding wire, for example, by resistance welding.

[0010] Because the base section of the contact element is narrower than the contacting section, the contact element has a small extent in a transverse direction perpendicular to the longitudinal axis. Combined with the planar shape of the contact element, this allows for a particularly compact contact element. As a result, the contact element according to the invention can be attached to the stator body before it is wound, without significantly reducing the windable cross-section of the stator body.

[0011] For example, when manufacturing the stator body by injection molding, the contact element can be inserted into the mold, eliminating the need for additional fasteners and process steps to attach the contact element to the stator. Furthermore, the planar shape of the contact element allows for particularly simple manufacturing. For instance, the contact element can be stamped directly from a sheet of metal without requiring any subsequent forming processes.

[0012] Preferably, the leg of the holding device is connected to the base section via an arc, which enables particularly reliable reception and electrical contact of the winding wire. Furthermore, this allows for high strength of the contact element in the assembled state.

[0013] Preferably, the inner radius of the arc section corresponds substantially to the radius of the winding wire. This allows the leg to be shaped to fix the winding wire in the holding device without significant deformation of the winding wire. This ensures reliable fastening and electrical contact of the winding wire.

[0014] In a preferred embodiment of the invention, the leg of the holding device is shorter than the base section of the holding device. This makes it possible to shape the leg for fixing the winding wire such that, after assembly, the free end of the leg is arranged longitudinally below the contacting section. This allows for a particularly small transverse expansion of the contact element in the assembled state.

[0015] Advantageously, before assembly, one free end of the leg points away from the longitudinal axis, and after assembly, it points towards the longitudinal axis. Because the free end of the leg points away from the longitudinal axis before assembly, the winding wire can be easily picked up by the holding device during winding. During assembly, the free end of the leg is reshaped to secure the winding wire, so that after assembly, the free end points towards the longitudinal axis. This allows for easy assembly of the electric motor.

[0016] In an advantageous embodiment of the invention, the distance between the base section and the free end of the leg is greater than the diameter of the winding wire before assembly and less than the diameter of the winding wire after assembly. This allows for easy insertion of the winding wire into the holding device before assembly and prevents the winding wire from slipping out of the holding device longitudinally in the assembled state.

[0017] Preferably, the free end of the leg extends laterally beyond the contact section before assembly, so that the winding wire can be reliably guided over the leg into the arc of the holding device. This allows for easy assembly of the electric motor.

[0018] In a preferred embodiment of the invention, the leg has an angle between 20° and 50° with respect to the base section before assembly. This enables reliable guidance of the winding wire into the holding device and thus simple assembly of the electric motor.

[0019] Advantageously, the contact element runs essentially straight and parallel to the longitudinal axis on the side opposite the leg. This allows the contact element to be manufactured with minimal waste while simultaneously providing sufficient durability.

[0020] In an advantageous embodiment of the invention, the difference in width between the base section and the contacting section corresponds essentially to the diameter of the winding wire, so that the winding wire is accommodated in the contact element essentially within the width of the contact lug. This allows a contact element with a particularly small transverse dimension, which essentially corresponds to the transverse dimension of the contacting section.

[0021] Preferably, the difference in width between the base section and the contacting section is less than half the width of the contacting section, ensuring sufficient mechanical stability of the base section and thus of the contact element.

[0022] In a preferred embodiment of the invention, the leg, in its undeformed state, has a width corresponding to 0.7 to 1.1 times the material thickness of the contact element. This allows for reliable and low-resistance electrical contact of the winding wire by the leg while simultaneously minimizing the transverse extent of the contact element.

[0023] Advantageously, the electrically effective cross-sectional area of ​​the contact element, which is determined by the product of the base section width and the material thickness of the contact element, corresponds essentially to twice the cross-sectional area of ​​the winding wire. This enables a compact contact element with simultaneously low electrical losses in the contact element.

[0024] In an advantageous embodiment of the invention, the contact element consists of a material with a low specific electrical resistance, for example, highly conductive copper. This enables a particularly low-resistance electrical contact with the winding wire, thereby minimizing the electrical losses of the electric motor.

[0025] Preferably, the contact element is coated, for example with a tin-silver alloy, to enable a particularly reliable welded connection between the contact element and the winding wire.

[0026] An embodiment of a contact element according to the invention for electrically contacting at least one winding wire of a stator of an electric motor is described below with reference to the accompanying figures, wherein Figure 1 a side view of a contact element according to the invention before assembly shows, and Figure 2 the contact element Figure 1 shown in the assembled state.

[0027] Figure 1 Figure 1 shows a contact element 10 according to the invention, which is essentially planar and has three successive sections in its main extension direction along a longitudinal axis L: a mounting section 12, a receiving section 14, and a contacting section 16. In the present embodiment, the contact element 10 is made of copper and has a coating of a tin-silver alloy. On a first transverse side 19, the contact element 10 extends essentially in a straight line and parallel to the longitudinal axis L, which passes through the center of the contacting section 16.

[0028] The mounting section 12 is designed for attaching the contact element 10 to a stator 36 of an electric motor. The mounting section 12 is essentially rectangular and extends along the longitudinal axis L. The mounting section 12 has a lateral mounting projection 18 at its longitudinal end facing the receiving section 14.

[0029] The receiving section 14 is designed to receive and electrically contact a winding wire 38 of a stator coil of the electric motor. The receiving section 14 comprises a base section 20 and a holding device 22 arranged laterally on the base section 20, with a leg 24 and an arc section 26. The holding device 22 is arranged on a second transverse side 27 of the contact element 10, which is opposite the first transverse side 19.

[0030] The base section 20 is essentially rectangular and extends along the longitudinal axis L. The base section 20 has a narrower width BB than the width BK of the contact section 16. The base section 20 is at least half as wide as the contact section 16. The difference between the width BB and the width BK corresponds essentially to the diameter of the winding wire, and the product of the width BB and the material thickness of the contact element 10 corresponds essentially to twice the cross-sectional area of ​​the winding wire. The leg 24 extends essentially in a straight line and points away from the fastening section 12 in the longitudinal direction and away from the longitudinal axis L in the transverse direction. In the present embodiment, the leg has a width BS that corresponds to 0.7 to 1.1 times the material thickness of the contact element. The leg 24 forms an angle W1 of approximately 35° with respect to the base section 20.Leg 24 is shorter than base section 20. Leg 24 is connected to base section 20 via arc section 26. The distance A1 between a free end 28 of leg 24, which projects laterally beyond contact section 16, and base section 20 is greater than the diameter of the winding wire. Arc section 26 has an inner radius R1, which essentially corresponds to the radius of the winding wire. The opening 30 of arc section 26 is laterally enclosed by base section 20 and leg 24 and points towards contact section 16.

[0031] The contact section 16 is designed to create an electrical connection between the contact element 10 and motor electronics. The contact section 16 runs essentially parallel to the longitudinal axis L on its transverse sides 19, 27. At its longitudinal end facing the receiving section 14, the contact section 16 has a transition section 32. In the transition section 32, the width of the contact section 16 changes continuously from width BK to width BB.

[0032] Figure 2 Figure 10 shows the contact element 10 in its assembled state. During assembly, the contact element 10, with its fastening section 12, is inserted into a corresponding receiving device of a stator body 34 of the stator 36 of the electric motor until the mounting projection 18 contacts it, and is then fastened to the stator body 34.

[0033] During assembly of the electric motor, the winding wire 38 is inserted into the arc section opening 30 of the holding device 22. The leg 24, which projects laterally beyond the contact section 16, serves as a guide for the winding wire 38. To fix the winding wire 38 in the holding device 22, the free end 28 of the leg 24 is bent in the direction of the longitudinal axis L, so that after assembly the free end 28 points in the direction of the longitudinal axis L. This reduces the distance A1 between the free end 28 and the base section 20 to a value smaller than the diameter of the winding wire 38.

[0034] The contact element according to the invention is simple and compact in design and allows for reliable electrical contact of the winding wire of the electric motor's stator. In particular, the compact design of the contact element according to the invention makes it possible to attach the contact element to the stator before it is wound. The small transverse dimension of the contact element prevents its leg from protruding into the stator's winding space, thus enabling the stator body to be wound with the winding wire despite the pre-mounted contact element.

[0035] It should be clear that the scope of protection of the present application is not limited to the described embodiments. In particular, the shape of the receiving section can be adapted to different winding wire diameters and winding methods. For example, the leg can be arranged at a different angle to the base section before assembly in order to adapt the contact element to different winding methods. Furthermore, other shapes of the mounting section and the contacting section are also conceivable in order to adapt the contact element to different designs of the stator body and the motor electronics. Reference symbol list

[0036] 10 Contact element 12 Mounting section 14 Receiving section 16 Contacting section 18 Mounting projection 19 First transverse side 20 Base section 22 Holding device 24 Leg 26 Arc section 27 Second transverse side 28 Free leg end 30 Arc section opening 32 Transition section 34 Stator body 36 Stator 38 Winding wire A1 Spacing BB Base section width BK Contact section width BS Leg width L Longitudinal axis R1 Arc section inner diameter W1 Angle

Claims

1. A contact element (10) for electrically contacting at least one winding wire (38) of a stator (36) of an electric motor, which is substantially planar and has three successive portions (12, 14, 16) along a longitudinal axis (L) which runs through the centre of a contacting portion (16) of the contact element (10): a fastening portion (12) for fastening the contact element (10) to the stator (36), a receiving portion (14) for receiving and electrically contacting the winding wire (38), and the contacting portion (16) for electrically connecting the contact element (10) to motor electronics, characterized in that the receiving portion (14) has a base portion (20) running along the longitudinal axis (L) of the contact element (10) and which, transversely to the longitudinal axis (L) of the contact element (10), has a smaller width (BB) than a width (BK) of the contacting portion (16) transversely to the longitudinal axis (L) of the contact element (10), and wherein a holding device (22) is arranged laterally on the base portion (20), which holding device is configured for arrangement of the winding wire (38) in the holding device (22) and which has a leg (24) pointing away from the fastening portion (12) in the direction of the longitudinal axis (L) of the contact element (10) and in a direction transversely to the longitudinal axis (L) of the contact element (10).

2. The contact element (10) according to Claim 1, characterized in that the leg (24) is connected to the base portion (20) via an arc portion (26).

3. The contact element (10) according to Claim 2, characterized in that the inner radius (RI) of the arc portion (26) corresponds to the radius of the winding wire (38).

4. The contact element (10) according to one of the preceding claims, characterized in that the leg (24) is shorter than the base portion (20) in the direction of the longitudinal axis (L) of the contact element (10).

5. The contact element (10) according to one of the preceding claims, characterized in that a free end (28) of the leg (24) faces away from the longitudinal axis (L) of the contact element (10) prior to assembly and faces the longitudinal axis (L) of the contact element (10) after assembly.

6. The contact element (10) according to one of the preceding claims, characterized in that the distance (Ai) between the base portion (20) and the free end (28) of the leg (24) prior to assembly is greater than the diameter of the winding wire (38), and after assembly is less than the diameter of the winding wire (38).

7. The contact element (10) according to one of the preceding claims, characterized in that the free end (28) of the leg (24) protrudes beyond the contacting portion (16) in a transverse direction to the longitudinal axis (L) of the contact element (10) prior to assembly.

8. The contact element (10) according to one of the preceding claims, characterized in that the leg (24) has an angle (WI) between 20° and 50° with respect to the longitudinal axis (L) of the contact element (10) prior to assembly.

9. The contact element (10) according to one of the preceding claims, characterized in that the contact element (10) runs rectilinearly and parallel to the longitudinal axis (L) of the contact element (10) on the side (19) opposite the leg.

10. The contact element (10) according to one of the preceding claims, characterized in that the difference in width between the base portion (20) and the contacting portion (16) corresponds to the diameter of the winding wire (38).

11. The contact element (10) according to one of the preceding claims, characterized in that the difference in width between the base portion (20) and the contacting portion (16) is less than half the width (BK) of the contacting portion (16) transversely to the longitudinal axis (L) of the contact element (10).

12. The contact element (10) according to one of the preceding claims, characterized in that the leg (24) in an undeformed state has a width (BS) transversely to a longitudinal extent of the leg (24) which corresponds to 0.7 to 1.1 times the material thickness of the contact element (10).

13. The contact element (10) according to one of the preceding claims, characterized in that the electrically effective cross-sectional area of the contact element (10), which is determined by the product of the base portion width (BB) and the material thickness of the contact element (10) corresponds to twice the cross-sectional area of the winding wire.

14. The contact element (10) according to one of the preceding claims, characterized in that the contact element (10) is coated.