CN107086694B

CN107086694B - Electric contact for an electric motor

Info

Publication number: CN107086694B
Application number: CN201710075855.4A
Authority: CN
Inventors: F·艾泽勒; D·莫尔登豪尔; F·韦勒
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2016-02-12
Filing date: 2017-02-13
Publication date: 2021-03-09
Anticipated expiration: 2037-02-13
Also published as: CN107086694A; DE102016202145A1

Abstract

The motor includes a coil having a coil wire and a rotational axis. A wire support for an electric motor includes a retaining structure for securing a section of coil wire in a plane of rotation about an axis of rotation. The holding structure is provided for allowing an end section of the coil conductor adjoining the fixed section to bend in the axial direction, so that the electric motor can be electrically connected by means of the end section, and for allowing a connecting element to be mounted axially on the fixed section of the coil conductor by means of a cutting and clamping technique, so that the electric motor can be electrically connected by means of the connecting element.

Description

Electric contact for an electric motor

Technical Field

The present invention relates to an electric motor. The invention relates in particular to an electric contact for an electric motor.

Background

The motor comprises a stator and a rotor which are rotatably mounted about a common axis of rotation. In an embodiment of the inner rotor, the stator is located radially outside and the rotor is located radially inside. The stator laminate stack comprises a stator laminate stack of a plurality of sheets stacked in the axial direction and fixed to each other. On the radially inner side of the stator, a plurality of slots are distributed over a circumference around the axis of rotation, the slots each extending in the axial direction. The coils of the coil conductors are located in at least two slots, wherein the coils usually project beyond the stator lamination stack at the axial end of the electric motor. It is common to support the axial ends of the coils in the radial direction in order to prevent the coils from coming into contact with the rotor.

In order to be able to use the motor, the ends of the coil wires must be electrically contacted. The contact portions may be implemented differently depending on the required profile for the motor. In one embodiment, the end section of the coil wire is retained on the motor and then electrically connected to a power source. Between the coil and the end section, the coil wire is usually fixed to the motor. In another embodiment, the coil wire is fixed to the motor and cut off. For the electrical contacting, separate connecting elements are attached to the remaining short end sections of the coil wires. The connection element may comprise, for example, a connection cable or an electrical socket connection.

Disclosure of Invention

The object of the present invention is to provide a technique for making it possible to carry out the contacting of the electric motor by means of the same components, optionally by means of end sections of the coil wires or by means of separate connecting elements.

The motor includes a coil having a coil wire and a rotational axis. A wire support for an electric motor comprises a holding structure for fixing a section of a coil wire in a plane of rotation about an axis of rotation. The holding structure is provided for allowing the end section of the coil wire adjoining the fixed fastening section to bend in the axial direction, so that the electric motor can be electrically connected by means of the end section, and for allowing the connecting element to be mounted axially on the fixed fastening section of the coil wire by means of the cutting and clamping technique (Schneid-Klemm-Technik), so that the electric motor can be electrically connected by means of the connecting element.

By means of the wire holder, it is possible to provide an electrical connection by means of the end section or by means of a separate connecting element after the coil has been mounted on the stator or rotor of the electric motor. The electric motor to be used in different ways can thus be constructed with the same components. The decision in which way the motor should be contacted can be made relatively late in the manufacturing process of the motor. The end section of the coil wire can for example remain until immediately before the motor is fitted into the appliance. If the appliance requires contact by means of a coil wire, the latter can be correspondingly bent over the holding structure and, if appropriate, cut off. If contact by means of the connecting element is alternatively required, the connecting element can be inserted into the holding structure and the excess end of the coil wire can be cut off.

The motor may be used in particular for hand tools. In one embodiment, the electric motor can be used, for example, in an angle grinder by means of electrical contact via coil wires and alternatively in a hammer drill by means of contact via a separate connecting element. The load of the motor in the angle grinder due to heat and dust may be greater than the load in the hammer. Thus, the electrical connection of the motor may be coordinated with the purpose of use of the motor.

Preferably, the holding structure has a groove for receiving the fixing section, wherein the groove is located in the plane of rotation and opens in the axial direction. The retaining structure is usually mounted in the region of an axial end of the electric motor. The coil wire emerges from the coil or the electric motor substantially in the axial direction. A first deflection, which supports the fixing of the coil wire, can be forced by inserting the coil wire into the groove. By the section running in the plane of rotation, it is possible to support the section against axial loads (as may occur, for example, during the mounting of the connecting element).

Preferably, the retaining structure further comprises a resiliently movable latching element which allows the securing section to be axially inserted into the slot and secures the inserted section against axial disengagement from the slot. The end section of the coil wire can be inserted into the groove of the holding structure by means of a simple movement and fixed by means of latching elements. The position of the fixed fastening section can thereby be defined with sufficient precision in order to facilitate automated reworking. At the same time, the securing section can be secured in such a way: this approach allows for two solutions for electrical contacts.

Furthermore, the retaining structure preferably has an axial recess which extends in both axial directions from the groove in order to receive a respective section of the connecting element. In other words, the holding structure preferably has an axial receptacle for the connecting element, wherein the recess is located in the region of the groove in order to facilitate electrical contact between the coil conductor and the connecting element.

In particular, it is preferred that the groove for the coil conductor running in the plane of rotation is interrupted by an axial recess. The coil wire can thereby be held on both sides with respect to the connecting element embodied in a cutting-clamping manner, so that the mounting of the connecting element can be facilitated.

In a further embodiment, the holding structure has a projection which extends the slot radially outward and is provided for being severed together with the end section of the coil wire. The coil wire can thus be supported on the enlarged surface, and the connecting element is fixed to the coil wire by means of a cutting clamping. In a further working step, which can be carried out integrally with the fastening of the connecting element, the radial projection can be severed together with the end section of the coil wire, so that on the one hand excess coil wire is removed and on the other hand the radial dimension of the electric motor can advantageously be kept small.

In a further embodiment, the wire holder comprises an abutment surface for supporting the axial end section of the coil in the radial direction. The wire holder can in particular be embodied integrally with the coil holder. The coil carrier can fix the radial position of the axial ends of the coil and by its integration with the wire carrier at the same time form positioning points for the electrical connection of the coil wires.

Particularly preferably, the wire holder further comprises an axial projection for being received in a corresponding recess of the electric motor. The cutouts can be arranged in particular in a rotor lamination stack or in a stator lamination stack, wherein the two lamination stacks can each be formed by axial stacking of magnetic conductive plates. The axial projection ensures the radial or rotational position of the wire or coil carrier relative to the rotor or stator lamination stack.

Furthermore, the wire holder is preferably embodied in one piece. The wire holder can in particular comprise a plastic and can be produced, for example, by injection molding.

A stator lamination stack for an electric motor comprises a stator lamination stack, a coil with coil leads and a coil support for fixing the coil to the stator lamination stack. Here, the lead frame is attached to the coil frame. The coil carrier and the line carrier are preferably embodied integrally with one another in one piece.

The motor includes the above-described stator and a rotor rotatably supported with respect to the stator. Preferably an asynchronous motor, which can be rectified mechanically or electrically.

Drawings

The invention will now be described in detail with the aid of the accompanying drawings, which show:

FIG. 1 is a schematic view of an electric motor;

FIG. 2 is an embodiment of a stator for an electric motor;

FIG. 3 is a different view of a retaining structure for the coil wire of the coil of the motor; and

fig. 4 is a view of the retaining structure of fig. 3 connected to a separate electrical connection element.

Detailed Description

Fig. 1 shows a schematic view of an electric motor 100. The stator 110 and the rotor 115 (not shown) are mounted rotatably relative to each other about the axis of rotation 105. Stator 110 includes a stator stack 120, which is typically constructed of a plurality of magnetically permeable plates stacked on top of each other in an axial direction. A plurality of slots 125, each extending in the axial direction and opening radially inward, are provided in stator stack 120. Preferably, the plurality of grooves 125 are distributed over a circumference around the axis of rotation 105, and further preferably are evenly distributed. One coil 130 typically includes a plurality of turns of coil wire 135 that pass through at least two slots 125. A plurality of coils 130 are typically provided, most of which are located in different slots 125 of stator stack 120.

Fig. 2 illustrates an embodiment of a stator 110 for the motor 100 of fig. 1. Both embodiments use one coil support 205 for radially supporting the coil 130 on an axial end of the electric motor 100. Fig. 2A shows such a coil support 205: this coil carrier enables a radial support of two coils 130 which are opposite one another about the axis of rotation 105, and fig. 2B shows an embodiment in which: in this embodiment, the coil carrier 205 is provided for supporting an axial end section of only one coil 130.

In the embodiment of fig. 2A, coil wire 135 is routed to a holding structure 210 of a wire holder 215, which may be implemented integrally with coil holder 205. In this case, the fastening section 220 of the coil wire 135 is fastened to the holding structure 210 in order to hold the end section 225 of the coil wire 135 in a position in which it can be contacted by means of an external electrical connection element (not shown). In the embodiment shown, the end sections 225 of the coil wires 135 of two different coils 130 abut one another and may also merge into one another. The same coil wire 135 may be used to wind up the plurality of coils 130. The contact of the electric motor 100 in the region of the end section 225 can be established, for example, by means of a threaded connection, a cut-and-clamped connection or a material-locking connection, such as soldering or welding. Preferably, an abutment surface 230 is provided on the coil support 205 for supporting the coil 130 in the radial direction. Coil 130 may be wound and then introduced axially into stator stack 120, wherein the projecting axial end may rest radially inwardly against contact surface 230.

In the embodiment of fig. 2B, the end section 225 of the coil wire 135 is led out and optionally electrically insulated by means of a sheath. The electrical connection of the electric motor 100 according to this embodiment is realized by an end section 225, which can be joined to the energy source, for example by means of a screw connection, a clamping connection or a material-locking connection, such as soldering or welding.

The invention proposes that a holding structure 210 be provided, which allows the electric motor 100 to be electrically contacted in the sense of the two embodiments shown in fig. 2. In this case, a one-piece element is preferably used, which integrates the wire holder 215 with the coil holder 205 and on which the holding structure 210 is formed. However, in another embodiment, the holding structure 210 can also be formed only on the coil carrier 205 or only on the wire carrier 215.

Fig. 3 shows different views of a holding structure for coil wires of a coil of a motor like the motor 100 of the above figures. These views are considered representative, but not necessarily binding for all embodiments of the retention structure 210. Fig. 3A shows a view from the radial inside, fig. 3B shows a view from the radial outside, fig. 3C shows an axial view looking into the stator lamination stack 120 and fig. 3D shows a longitudinal section of the retaining structure 210. The cutting plane runs parallel to the axis of rotation 105.

The holding structure 210 preferably extends substantially cylindrically in the axial direction of a wire holder 215 provided for mounting on an axial end of the electric motor 100 or stator stack 120. For fastening the wire holder 215 on the stator lamination stack 120, an axial projection 305 is preferably provided, which can be conically shaped as shown and is provided for being received in a corresponding recess of the stator lamination stack 120. A groove 310 for receiving the fastening section 220 of the coil wire 135 is formed on the holding structure 210. The grooves 310 extend in a radial direction or along a plane of rotation about the axis of rotation 105. The groove 310 is open in the axial direction.

Preferably, the retaining structure 210 includes an axial indentation 315 for receiving an electrical connection element, which is described in more detail below with reference to fig. 4. The axial gap 315 preferably interrupts the slot 310 such that segments of the slot 310 are located on different sides of the gap 315. The notch 315 preferably extends in both axial directions relative to the slot 310. Optionally, the groove 310 is elongated on the radial outside with respect to the rotation axis 105 by means of a radial projection 320. The projection 320 is preferably designed in a material-saving manner, so that it can be easily sheared or cut off in the axial direction.

In the region of the groove 310, a latching element 325 is preferably provided, which is provided to allow axial insertion of the coil wire 135 and to prevent subsequent axial removal as far as possible. Preferably, latching elements 325 are formed on a section of retaining structure 210, which extends from groove 310 in the axial direction away from stator lamination stack 120. The latching element 325 preferably comprises a latching hook 330 which is elastically movable in a direction substantially parallel to the plane of rotation about the axis of rotation 105 and has a first axial surface 335 which is angled relative to the plane of rotation and points in the axial direction away from the stator lamination stack 120, and a second axial surface 340 which is substantially parallel to the plane of rotation and faces the stator lamination stack 120. If the coil wires 135 are introduced into the slots 310 in the axial direction towards the stator lamination stack, the snap hooks 330 are laterally offset by the inclined first axial surface 335 and allow the coil wires 135 to pass in the axial direction. After passing, the latch hook 330 springs back. If the penetrated section of coil wire 135 is subsequently removed from stator stack 120 in the axial direction, it moves against second axial surface 340, which is detrimental to the swing-out of latch hook 330. As a result, coil wire 135 is fixed to latching element 325. In the illustration of fig. 3, the section of the coil wire 135 which is located in the radially inner region of the slot 310 with respect to the axial recess 315 is considered to be the fixed section 220 of the coil wire 135.

After the coil wire 135 has entered the slot 310, the end section 225 can be bent in the axial direction such that it is located in a portion of the gap 315. Optionally, the end section 225 can also be cut off, insulated and prepared on its end for electrical connection to an energy source.

Fig. 4 shows a view of the holding structure 210 of fig. 3 connected to a separate electrical connection element 405. Fig. 4A shows a view from the radially inner side and fig. 4B shows a view from the radially outer side, respectively, with respect to the rotational axis 105 of the motor 100. The connecting element 405 is provided for electrical and mechanical connection to the coil wire 135 by means of a cutting clamping method. For this purpose, the connecting element 405 preferably comprises a contact tongue 410 which is forked at the axial ends and is provided with a cutting surface between the respective ends. The contact tongues 410 are sufficiently rigid to be introduced into the recesses 315 in the axial direction, cut through any insulating varnish of the coil wire 135 and to bear by clamping action on the coil wire 135 and preferably also on the boundary of the recesses 315. In the embodiment shown, the connection element 405 additionally comprises a press connection 415 for electrical and mechanical connection with a connection cable 420. The connection cable 420 may be comprised by the connection element 405.

To mount the connecting element 405, the coil wire 135 is inserted in the axial direction into the groove 310 such that its end section 225 is preferably directed radially outward. The connecting element 405 is then inserted in the axial direction into the axial recess 315 and is thereby electrically connected to the coil wire 135. Optionally, the end section 225 on the holding structure 210 can then be cut or sheared off. In one embodiment, the radial projections 320 are also cut or sheared together for the purpose of abutting the coil wire 135.

Claims

1. A wire holder (215) for holding a holding section (220) of a coil wire (135) of a coil of an electric motor (100), wherein the wire holder (215) comprises:

-a holding structure (210) for fixing a fixing section (220) of the coil wire (135) in a rotation plane around a rotation axis (105) of the electric motor (100),

-wherein the holding structure (210) is provided for,

-enabling an end section (225) of the coil wire (135) adjoining the fixed section (220) to be bent in an axial direction such that the electric motor (100) can be electrically connected by means of the end section (225), and

-enabling a connecting element (405) to be mounted axially on the fixed section of the coil wire (135) that is fixed by means of a cut-and-clamp manner, such that the electric motor (100) can be electrically connected by means of the connecting element (405),

-wherein the holding structure (210) comprises a slot (310) for receiving the fixing section (220), wherein the slot (310) lies in the plane of rotation and has an opening in the axial direction, wherein the holding structure (210) has a projection (320) which elongates the slot (310) radially outwards and which is provided for being severed together with the end section (225) of the coil wire (135).

2. The wire rack (215) of claim 1, wherein the retaining structure (210) comprises a resiliently movable snap-in element (325) that allows the securing section (220) to be axially inserted into the slot (310) and secures the inserted securing section (220) from being axially disengaged from the slot (310).

3. The wire holder (215) according to claim 1 or 2, wherein the retaining structure (210) has an axial recess (315) which extends from the groove (310) in both axial directions for receiving a respective section of the connecting element (405).

4. The wire holder (215) according to claim 3, wherein a slot (310) for the coil wire (135) extending in the plane of rotation is interrupted by the axial notch (315).

5. The wire holder (215) according to claim 1 or 2, further comprising an abutment surface (230) for supporting an axial end of the coil (130) in a radial direction.

6. The wire holder (215) of claim 1 or 2, further comprising an axial projection (320) for being received in a corresponding indentation of the electric motor (100).

7. The wire holder (215) according to claim 1 or 2, wherein the wire holder (215) is embodied in one piece.

8. Stator (110) for an electric motor (100), wherein the stator comprises a stator lamination stack (120), a coil (130) with coil wires (135) and a coil support (205) for fixing the coil (130) on the stator lamination stack (120), wherein a wire support (215) according to any one of the preceding claims is mounted on the coil support (205).