CN110365166B

CN110365166B - Electrical drive unit with a pole housing and an electronics housing

Info

Publication number: CN110365166B
Application number: CN201910266200.4A
Authority: CN
Inventors: 程凤妹; R.克鲁姆
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2018-04-04
Filing date: 2019-04-03
Publication date: 2024-04-26
Anticipated expiration: 2039-04-03
Also published as: DE102018204991A1; CN110365166A

Abstract

The invention relates to an electrical drive unit, in particular for adjusting movable components in a motor vehicle, comprising a housing, which has a metallic pole housing, which accommodates a stator and a rotor, and which further has a separately produced electronics housing, which is connected axially to the housing, which accommodates an electronics unit, wherein at least one contact element is integrated in the electronics housing, which forms an electrically conductive connection between the pole housing and the electronics housing in order to form a ground connection, wherein the contact element bears resiliently against the inner side of the pole housing with at least one axial free end, and the free end is bent axially downward from the tangential direction from a fastening region of the contact element, which extends transversely to the rotor axis, such that the free end extends approximately in the axial direction.

Description

Electrical drive unit with a pole housing and an electronics housing

Technical Field

The invention relates to an electrical drive unit according to the invention with a pole housing and an electronics housing.

Background

An electrical machine is known from DE 10 2012 222 683 A1, which has a pole pot made of metal. On the pole pot, a plug member made of plastic is arranged axially, on which in turn a cover made of an electrically conductive material is arranged. The cover and the pole pot are clamped by a plurality of steel spring clamps, so that the three components are fixed relative to one another. The steel spring clip, together with the pole housing and the metal cover, serves here as an EMV shield which shields the injection and ejection of interfering electromagnetic waves. The installation of such external metal springs is rather cumbersome and creates a construction space strain. There is furthermore the following risk: that is, these metal springs are corroded and thereby adversely affect their transition resistances. Additionally, a shielding plate may be arranged around the plug member, which is electrically connected to the cover and/or the pole pot. However, the production and installation of such shielding plates likewise constitutes a considerable additional outlay.

DE 10 2017 207 165.6, which is disclosed later by the present inventors, discloses a drive unit in which contact elements are integrated inside an electronics housing in order to connect the electronics housing to an electrical ground (ELEKTRISCHE MASSE) of a pole housing. In the case of severe vibrations and large thermal loads, there are the following risks: the spring contacts on the pole housing are thus released, and the electronics housing is thereby no longer reliably electrically shielded. This problem is solved by the present application as described below.

Disclosure of Invention

In contrast, the electrical drive unit according to the invention has the following advantages: that is, the free end in the axial direction is prevented from moving radially inwards under vibration and thermal load by bending it axially downwards from the tangential direction and thus away from the inner wall of the pole housing. By providing the free end with a certain relaxation behavior after bending thereof, which forces the axial tab back to its original state in tangential direction, it is thereby always ensured that the spring force increases in radial direction even under high load, thereby ensuring a reliable electrical contact with the ground connection.

Advantageous improvements and improvements of the features presented in the present disclosure are obtained by the measures presented in the claims. If, for example, exactly two free ends are bent axially downward in the tangential direction on the contact element, these two free ends form a U-shaped spring contact with the pole housing. If the two free legs of the U-shaped fork contact are moved away from each other in the tangential direction, the two legs bear radially outwards on the inner wall of the pole housing. Even if one leg moves radially inward, the tangentially opposed leg is thereby pressed radially outward. Thus, a reliable ground connection to the pole housing is always ensured by the two parallel legs of the fork-shaped contact.

By bending at least one free end of the contact element from the spring plate into a press-bent piece, there is always a tendency to follow through the relaxation properties of the material: i.e. the free end is bent back to the original position of the bent plate. However, by this movement of the free end in tangential direction, the radial pressing force acting on the circularly curved inner wall of the pole housing is further enhanced. In contrast, if in the known solution the free end is initially bent axially downwards in the radial direction from a plane transverse to the rotor shaft, such a free tab is bent radially away from the inner wall of the pole housing upon a loosening movement.

Preferably, the free end has a cross section whose radial extent is significantly greater than its extent in the tangential direction. On the one hand, this makes the contact in the radial direction on the inner wall of the pole housing more punctiform, so that a greater contact pressure is achieved. On the other hand, by virtue of its cross section, the inward bending of the axial webs in the radial direction is significantly more difficult.

By a suitable choice of the tangential distance of the two free ends, which is approximately 2 to 5mm, and a corresponding bending radius towards the fastening region, which is approximately 1 to 2mm, the radial contact point of the spring contact with the pole housing can be optimized. In this way, even under strong vibration loads or strong temperature differences, the radial contact force of the free end with respect to the pole housing is increased, so that the ground connection is reliably ensured under all operating conditions.

If an elongated recess is formed in the contact element in the radial direction in the region of the at least one free end which is bent axially downwards from the tangential direction, this portion of the contact element is reinforced against bending in the axial direction. The axial free ends are thereby reliably held in their radial position, in which they bear elastically against the inner wall of the pole housing.

In order to further support the positioning accuracy of the free end, both the fastening region extending transversely to the rotor shaft and the part of the axial webs forming the free end are injection-molded with the plastic of the electronics housing. This means that a part of the longitudinal extension of the axial webs is fixedly injection molded with plastic and that only the axially lower region of the free end protrudes axially from the wall of the electronics housing. For this purpose, for example, latching elements are stamped out on the axial webs, which form a positive fit with the injection molding encapsulation realized by the housing.

In order to position the contact element precisely inside the electronics housing, for example, a centering hole is punched in the fastening region of the contact element, into which a corresponding centering pin of the injection mold is inserted. The radial position of the free end and thus the radial contact force acting on the inner wall of the pole housing can be precisely predefined.

The contact elements are used for the ground connection of the circuit board or for the metal shielding of the electronics housing. For this purpose, the contact elements are in electrical contact with the circuit board or the metallic housing part at the opposite end of the free end. For example, the contact elements can be connected by means of soldering or pressure welding or an elastic plug connection. If the housing part of the electronics housing is composed of metal, it can be connected directly to the pole housing via the corresponding contact element, but can also be contacted indirectly by an electrical connection to the circuit board. Preferably, the electronics housing has a separately produced metal cover which is electrically connected to the circuit board via spring contacts arranged on the circuit board.

In order to connect the electronics housing to the pole pot, a cylindrical circumferential wall is formed on the electronics housing as an axial projection, which is inserted into the pole housing. Correspondingly, a first radial step is formed on the flange of the pole housing, which carries an axial projection. The inner wall of the pole housing forms a second step in the radial direction, radially deeper, against which the axial free end bears radially elastically in order to form a ground contact. The axial free ends thus have sufficient radial free space to make radially elastic electrical contact with the pole housing.

The contact element can preferably be embodied as an insert which is inserted into the mold when the first housing part is injection-molded with plastic, in order then to be injection-molded with the plastic of the housing wall. The contact element is thereby fixed in the working step of producing the first housing part. In an alternative embodiment, it is also possible for the contact element to be formed as an insert which is pressed into a corresponding receptacle in the interior of the housing part after the housing part has been injection molded. For example, the insert can be manufactured cheaply as a bend-stamping and can be shaped very flexibly.

In a preferred embodiment, an electronic printed circuit board with different electronic components is arranged in a first housing part made of plastic. The electronic unit is protected from undesired electromagnetic interference radiation by the contact element according to the invention inside the first housing part made of plastic. While preventing the electronics unit from emitting disturbing electromagnetic radiation to the outside. For this purpose, the contact elements electrically connect the pole housing, which is made of metal, to the electronic printed circuit board. The electronic printed circuit board is also electrically conductively connected to a second axial housing part which is composed of metal. By having the electronic printed circuit board in contact with both the pole housing and the metallic housing cover ground, a faraday cage for EMV-shielding of the electronic printed circuit board is actually provided.

In a further embodiment, the contact element can also connect the pole housing to the second housing part made of metal, without contact being made here with the electronic printed circuit board or other electronic components. In this case, a ground contact is produced between two housings made of metal, between which a first housing part made of plastic is arranged. In this way, the entire housing cover made of metal is advantageously grounded, so that any electronic component or electronic circuit board can be directly electrically connected to the housing cover made of metal in order to achieve a ground contact.

In a preferred embodiment, the contact element is electrically connected on the one hand to the electronic printed circuit board and on the other hand to the pole housing of the electric motor. In this case, the contact elements are connected both electrically conductively to the electronic printed circuit board and to the pole housing by means of different contact methods, such as soldering or welding or soldering or pressing, or by means of spring contacts. The contact method can be adapted to the method of mounting the electronic printed circuit board in the first housing part, for example, so that no further additional mounting steps are required.

The electrical connection between the electronic printed circuit board and the housing cover made of metal is particularly advantageously realized in terms of method technology by contact springs which are previously contacted and arranged on the electronic printed circuit board. In this case, electrical contact is made between the electronic printed circuit board and the housing cover while the housing cover is axially mounted, in such a way that the contact spring is axially elastically pressed against the inner side of the metal cover. The grounding contact between the pole housing and the metal cover is formed here on the one hand by contact elements inserted into the housing wall of the first housing part and on the other hand by contact springs between the electronic printed circuit board and the metal cover.

By forming the centering pins on the contact elements while making electrical contact with the electronic printed circuit board and/or the housing cover, the housing parts can also be simultaneously aligned with each other in order to facilitate their axial mounting with respect to each other. Accordingly, a centering receptacle can be arranged on the electronic printed circuit board and/or on the inner side of the housing cover, into which centering receptacle the centering pin is inserted when axially mounted. Thereby omitting the additional centering element arranged for axially mounting the individual housing parts. In order to connect the pole housing to the first housing part, holes are formed, for example, in the flange of the pole housing, through which screws can be screwed into the electronics housing.

If the contact element is electrically contacted with the electronic printed circuit board and/or the housing cover by means of a contact pin, the contact pin can advantageously be accommodated in a centering receptacle, which is embodied, for example, as a speed nut (Speednut). By inserting the contact pin into the speed nut device, on the one hand, a reliable, elastically abutting electrical contact is produced, and at the same time a reliable centering of the housing parts relative to one another is also achieved. If the second housing part is configured as a cooling body for an electrical drive unit, the electronic component can be arranged inside the first housing part in direct thermal contact with the inner side of the housing cover (as the second housing part). The contact element can also serve as a heat conductor. The housing cover is cast from aluminum, for example, or deep drawn as sheet metal. By the cooling ribs formed on the outer side face, heat generated by the electronic device can be rapidly discharged. The first housing part made of plastic is arranged in a sandwich-type design between the housing cover and the pole housing made of metal. In this case, the connection plug thereof preferably extends in a radial direction away from the rotor shaft.

By arranging the electronic unit axially directly above the electric motor, a signal generator can advantageously be arranged on the end of the rotor shaft, which signal generator interacts with a corresponding sensor of the electronic unit. In this way, the rotor position can be detected by the electronic unit, for example, in order to control the electronic commutation of the electric motor, or to determine the rotational speed of the rotor shaft or the position of a component driven by the rotor shaft. On the open side of the pole pot, a bearing cap is preferably arranged, in which the rotor shaft is supported, for example by means of a rolling bearing. The bearing cover is in particular an integral part of the first housing part and is thus made of plastic. The rotor shaft passes through the bearing cap and protrudes into the electronics housing, wherein the signal generator is preferably arranged at the free end of the rotor shaft. It is particularly advantageous if the signal generator outputs signals in the axial direction, which signals can be detected by axially directly opposite sensor elements. In this case, it is particularly advantageous if the sensor element is arranged directly on the circuit board, wherein the sensor element can detect the orientation of the magnetic field, for example. By arranging the electronics housing on the axially open side of the pole pot, a through opening can be constructed in the bottom of the pole pot on the opposite side of the pole pot, through which through opening the rotor shaft protrudes outwards. On the second axial free end of the rotor shaft, a driven element can thereby be formed or arranged, which can, for example, adjust a movable component in a motor vehicle or drive a pump or a blower. The drive unit is practically completely surrounded by the faraday cage together with the metallic housing cover and the contact elements connecting them by the metallic bottom surface of the pole pot and the metallic circumferential wall, which in particular simultaneously forms a magnetic yoke for the stator coil. Thus, neither electromagnetic interference radiation is emitted from nor is electromagnetic interference radiation emitted into the drive unit.

Drawings

Other features of the invention will be apparent from the following description of the invention and from the accompanying drawings, which are incorporated in the subsequent embodiments of the invention. Wherein:

Fig. 1 shows a first design of an electrical drive unit according to the invention; and

Fig. 2 shows a detailed view of another embodiment.

Detailed Description

Fig. 1 shows an electrical drive unit 10, which is designed as an electric motor 9 with a housing 11. A stator 60 having a plurality of stator poles is arranged in the pole housing 12 of the housing 11, which stator interacts with a rotor 62 arranged on the rotor axis 20. The rotor 62 has a rotor shaft 64 on which a rotor body 66 is arranged, which preferably consists of a single plate stack 67. The rotor shaft 64 is supported on the bottom 14 of the pole housing 12 by means of a first bearing 68 in this embodiment. For this purpose, the pole housing 12 has an axial projection 16, which is designed as a bearing seat for the first bearing 68. The pole housing 12 is formed as a pole pot 13, which is produced, for example, as a deep-drawn part. The rotor shaft 64 protrudes with an axial second end 63 out of the pole housing 12 through a bore 70 of the latter, in order to transmit the torque of the electric motor 9 to a transmission or a pump or blower, not shown in detail. The bores 70 are formed on the axial projections 16, wherein a driven element 74 is arranged on the rotor shaft 64 or molded on the rotor shaft 64 outside the pole housing 12. The pole housing 12 is constructed of metal and is optionally configured as a magnetic yoke for the electromagnetic poles of the stator 60. When the electric motor 9 is configured as an EC motor 8, electrical coils 76 are arranged on the stator teeth in the stator 60 in the radially outer region of the pole housing 12, which coils generate a magnetic field in order to put the permanent magnets 78 arranged in the rotor 62 in rotation. In this exemplary embodiment, the pole housing 12 is embodied as a substantially cylindrical pole pot 13, which is embodied in an axially open manner. A bearing cover 50, in which the second bearing 58 of the rotor shaft 64 is fastened, is arranged on the axial opening 80 of the pole housing 12. The bearing cap 50 is, for example, a component of the first axial housing part 31 of the electronics housing 30, which is made of plastic. The first housing part 31 is inserted axially with the bearing cap 50 at the edge 81 of the opening of the pole housing 12. A first free end 65 of the rotor shaft 64, which is opposite the driven element 74, passes through the second bearing 58, on which first free end a signal generator 83 for detecting the rotor shaft position is arranged. In the first housing part 31, a connection device 77 is arranged, which connects the individual coils 76 to one another and which axially projects the electrical terminals 75 from the interior of the pole housing 12 into the electronics housing 30. The pole housing 12 forms, with the rotor 62 completely supported therein, a pre-mounted construction unit 18 to which the different housing components 31 can be flanged axially. For this purpose, a flange 22 is formed on the edge 81 of the opening of the pole housing 12, against which flange the electronics housing 30, which in this embodiment is composed of an axial first housing part 31 and an axial second housing part 32, is axially attached. The pole housing 12 and the electronics housing 30 together form the housing 11 of the drive unit 10.

The first axial housing part 31 axially rests against the pole housing 12. For this purpose, the axial first housing part 31 has a cylindrical circumferential wall 23 which is inserted axially into the pole housing 12. In this case, a first radial step 108 with an axial annular rim, to which the circumferential wall 23 is axially supported, is formed on the open edge 81 of the pole housing 12. Between the axial annular rim and the axial end face of the circumferential wall 23 a sealing ring 24 is arranged with which the pole housing 12 is sealed against the electronics housing 30. The flange 22 and the circumferential wall 23 are of approximately circular design, wherein the base surface of the first axial housing part 31 is of approximately rectangular design, for example, as seen from above in the plan view of fig. 1, and protrudes radially from the pole housing 12. The axial first housing part 31 has a mounting opening 40 on the side axially facing away from the pole housing 12, which is completely closed by the axial second housing part 32. This means that the electronics housing 30 has a separation plane 34 transverse to the rotor axis 20, at which two separately produced axial housing parts 31, 32 are connected to one another. According to the embodiment in fig. 1, the axial first housing part 31 has an axial contact surface 35 axially opposite the circumferential wall 23, which contact surface contacts a counter surface 36 of the second housing part 32. Between the contact surface 35 and the counter surface 36, a circumferential sealing element 39 is preferably arranged. The second housing part 32 is connected to the first housing part 31, for example by means of a clampband 48. In order to center the second housing part 32 relative to the first housing part 31, centering pins 33 are arranged, which are inserted into corresponding centering receptacles 37. The first housing part 31 is preferably connected to the flange 22 of the pole housing 12 by means of screws 38. The mounting opening 40 is of substantially rectangular design in the separating plane 34. The contact surface 35 and the counter surface 36 enclose the mounting opening 40 and are therefore likewise of substantially rectangular design. The first housing part 31 is made of plastic and the second housing part 32 is made of aluminum or steel plate for better heat dissipation. For example, the aluminum housing part is produced by means of an injection molding process or a die casting process. In this case, heat conducting elements 28 are formed on the outer wall of the second housing part 32, which are embodied, for example, as cooling ribs 29 or cooling projections. Integrated into the first housing part 31 are contact elements 100 which form an electrically conductive connection between the pole housing 12 and the second housing part made of metal. For this purpose, in this exemplary embodiment, the contact elements 100 are embodied as inserts 101, which are injection molded over the first housing part 31 during the injection molding of the first housing part. The contact element 100 is electrically connected to the pole housing 12 at a first free end 102. For this purpose, the first free end 102 is designed as a spring contact 103, which rests elastically against the inner wall of the pole housing 12. The contact element 100 is configured as a stamped and bent part with a fastening region 106, at which the contact element 100 is injection molded with the plastic of the electronics housing 30. The fastening region 106 extends in a plane transverse to the rotor shaft 64, wherein the at least one free end 102 extends in the tangential direction 26 in the plate-plane before it is bent downward as spring contact 103 in the axial direction 25. The first free end 102 protrudes in the axial direction 25 from the housing wall of the electronics housing 30 and is pressed radially outwards by the spring force against the cylindrical inner wall of the pole housing 12. When the first housing part 31 is mounted, the spring contact 103 is pressed in the axial direction 25 by a further second circumferential step 109, which deflects the spring contact 103 radially. By bending the free end 102 downward from the tangential direction 26, the slackening movement of the bent free end 102 causes movement in the tangential direction 26, thereby causing the free end 102 to press radially outward more strongly against the circular inner wall of the pole housing 12. This ensures that the spring contact 103 is electrically connected to the pole housing 12 reliably even in the event of vibration loading and large temperature fluctuations of the electric drive 10.

In a first variant, the second end 104 of the contact element 100 is in direct electrical contact with the circuit board 88, for example by means of soldering, pressing in or Schned a clamping connection. For this purpose, the second end 104 likewise protrudes from the plastic wall of the first housing part 31 and, for example, into a hole in the circuit board 88. At least one contact spring 110 is electrically contacted on the circuit board 88, which contact spring forms a ground connection with the inner side of the second housing part 32. The grounding connection between the pole housing 12 and the second housing part 32, which is achieved by the contact element 100, the circuit board 88 and the contact spring 110, is thus formed completely inside the housing 11. Preferably, exactly three such contact elements 100 are inserted inside the first housing part 31, which contact elements are connected to the circuit board 88 in three different positions. Accordingly, in the immediate vicinity of the second end 104 of the contact element 100, exactly three contact springs 110 are arranged in an electrically conductive manner between the circuit board 88 and the inner side of the second housing part 32.

On the right in fig. 1, a further variant of a contact element 100 is shown, which connects the pole housing 12 directly, in particular without contacting the circuit board 88, electrically to the second housing part 32. The first end 102 in turn rests as a spring contact 103 against the inner wall of the pole housing 12 and extends directly inside the plastic wall of the first housing part 31 to the inside of the second housing part 32. The second end 104 in turn protrudes from the plastic wall of the first housing part 31 and directly contacts the second housing part 32 when it is axially mounted. The second end 104 can be elastically placed directly against the inner wall of the second housing part 32 or can be contacted by means of the speed nut element 112.

For mounting the electric drive unit 10, the prefabricated construction unit 18 is first connected, preferably screwed, to the first axial housing part 31. The first free end 102 is simultaneously in electrical contact with the pole housing 12 when the first housing part 31 is axially mounted. In this state, the first housing part 31 can be axially fitted with the circuit board 88 and optionally with other components via the mounting opening 40. The circuit board 88 is fastened to the inner side of the first housing part 31 before the axial second housing part 32 is axially placed onto the mounting opening 40 of the first housing part 31. Instead of adhesive bonding, the circuit board 88 can also be screwed or snapped into the electronics housing 30 either hard or soft. For vibration protection, the circuit board 88 can also be supported in a floating manner or in a vibration-damped manner by means of spring elements. In this case, the second end 104 of the contact element 100 can also be electrically connected, in particular soldered, to the circuit board 88. Likewise, the second housing part 32 can be fitted with the corresponding components before it is mounted on the first housing part 31. In this exemplary embodiment, a connection plug 42 for electrically contacting the drive unit 10 is integrally formed on the first housing part 31. The connection plug 42 has a plug collar 45 in which a single contact pin 46 for supplying power and sensor signals is arranged. The plug collar 45 here leaves the first housing part 31 radially outwards. Inside the electronics housing 30, a first interference-free element 52, which has, for example, an interference-free capacitor 53, is arranged on the circuit board 88. When the circuit board 88 is mounted in the first housing member 31, the contacts 75 and the contact pins 46 forming the coil 76 are electrically connected to the circuit board 88. Such an electrical connection may be achieved by an anti-interference element 52, for example having ELCO and/or an anti-interference choke. The first contact element 100 is preferably arranged directly in the vicinity of the connection plug 42 and the second contact element 100 is arranged directly in the vicinity of the interference-free element 52. On the circuit board 88, on the side facing the pole housing 12, a sensor element 94 is arranged, which can evaluate the signal of the signal generator 83. For example, the signal generator 83 is configured as a sensor magnet 84 whose axial magnetic field can be detected by a sensor element 94 configured as a magnet sensor 95. The sensor element may be configured, for example, as a GMR sensor or a GMX sensor, which can directly detect the rotational position of the sensor magnet 84. The electronic unit 89 can evaluate the signal in order to thereby, for example, control the electronic commutation of the EC motor 8. In addition, the rotational position signal may also be used to move the driven element 74 for different applications.

Fig. 2 shows an alternative embodiment, in which the free ends are bent in fork fashion onto the fastening region 106 of the contact element 102. For a better view of the contact element 100, the electronics housing 30 is not shown in fig. 2, with the plastic of which the fastening region 106 is injection-molded. Likewise, only the stamped grid of the wiring device 77 is shown, along with its fork contacts, but the plastic used to injection mold the stamped grid over the wiring device 77 is not shown. According to a preferred embodiment of the invention, both the plastic of the connection device 77 and the plastic in which the fastening region 106 is embedded are integral parts of the electronics housing 30. The electronics housing is mounted axially with a circumferential cylindrical circumferential wall 23 on the axial opening of the pole housing 12. As shown in fig. 1, the pole housing 12 in turn has a first radial step 108, into which the cylindrical circumferential wall 23 of the electronics housing 30 is inserted. The second step 109, against which the spring contact 103 is pressed radially outwards, is then formed in the pole housing 12 deeper radially inside. The contact element 100 is stamped and bent, for example, from a sheet material which has, in particular, a copper component. The illustrated fastening region 106 of the contact element 100 extends substantially in a plane transverse to the rotor shaft 64 and extends inside a housing bottom made of the plastic of the electronics housing 30. The second end 104 of the contact element 100 is then bent axially upward at the desired location to contact the circuit board 88 or alternatively directly contact the second housing part 32, which is composed of metal. The fastening region 106 has an aperture 107 which is suitable for precisely positioning the contact element 100 in an injection mold in which the electronics housing 30 is injection molded. The contact element 100 is here positioned as an insert in the mold by means of a centering pin which is axially inserted into the bore 107. In a further radial extension towards the free end 102, a groove 105 extending in the radial direction 27 is formed in the fastening region 106. The groove 105 stabilizes the fastening region 106 in order to prevent buckling due to spring forces acting radially on the free end 102. Thus, free end 102 should remain within its axial extent and not bend radially inward toward rotor shaft 64. In order to form the spring contact 103, the two webs are bent downward in the axial direction 25 by approximately 90 degrees, which webs extend first of all in the opposite tangential direction 26 after the stamping of the contact element plate. A radius of curvature 111 is formed here, which extends axially downward in tangential direction 26 from a plane transverse to rotor shaft 64. The two opposite bending radii 111 thus form a downwardly open U with approximately two free ends 102. Between the two bending radii 111, the material extends integrally in the radial direction 27 towards the fastening region 106, so that the entire contact element 100 is integrally formed as a stamped-bent piece. In this exemplary embodiment, small hooks 96 are formed on the axial webs of the free end 102, which hooks, when injection-molded with the electronics housing 30, engage in the wall material of the electronics housing 30. This means that only the axially lower part of the axial tab 97 protrudes from the wall of the electronics housing 30. Due to the bending process of the two free ends 102 arranged in a fork-like manner, the two axial webs 97 strive to return to their original position in the tangential direction 26 before bending, as a result of which the clear width of the two free ends 102 in the tangential direction 26 is increased, so that these free ends 102 press radially outwards to a greater extent against the circular inner wall of the pole housing 12. The cross-section of the two free ends 102 is preferably rectangular. The width in the tangential direction 26 is here the sheet thickness of the punched bending piece and is designed to be significantly shorter than the extent in the radial direction 27, which is preferably a multiple of the width in the tangential direction 26. The plate made of copper alloy has a thickness of, for example, between 0.4 and 0.8mm, in particular 0.6 mm. When the two free ends 102 are bent, these have a spacing in the tangential direction 26 of, for example, about 2 to 5 mm. The bending radius 111 is, for example, 0.5 to 1.5mm, with which the two free ends 102 are bent downward in the tangential direction 26 from a plane transverse to the rotor shaft 64.

It should be noted that various combinations of individual features are possible with respect to one another for the embodiments shown in the figures and the description. The design of the two housing parts 31, 32 can also differ from a rectangular shape and can be configured round or oval, for example, as can the pole housing 12. Instead of a screw connection between the pole housing 12 and the first housing part 31 or the two housing parts 31, 32, other connection techniques, such as crimping, snap-in, joggling, etc., can also be used. The electronics housing 30 can be constructed in a multi-component manner, in particular with a metal cover. Alternatively, the electronics housing 30 can also be constructed in one piece, in particular completely as a plastic injection molding. Depending on the design of the drive unit 10, the electronics housing 30 can accommodate various electronic functional components, such as the sensor means 94, 83, the interference-free elements 52, 53 and the EC motor control means 90, wherein at least electrical contact to the coil 76 must always be made. The drive unit 10 according to the invention is particularly suitable for being designed as an EC motor 8 for adjusting a movable component or for a rotary drive in a motor vehicle. Such an electric motor 9 according to the invention can be used particularly advantageously in external areas, such as motor spaces, where the electric motor is subjected to extreme weather conditions and vibrations.

Claims

1. An electrical drive unit (10) for a movable part in a motor vehicle, comprising a housing (11) having a metallic pole housing (12) which accommodates a stator (60) and a rotor (20), and comprising a separately produced electronics housing (30) which is axially connected to the housing and accommodates an electronics unit (89),

Wherein at least one contact element (100) is integrated inside the electronics housing (30), which forms an electrically conductive connection between the pole housing (12) and the electronics housing (30) in order to form a ground connection, wherein the contact element (100) bears elastically against the inner side (15) of the pole housing (12) with at least one axial free end (102), and the free end (102) is bent axially downwards from a tangential direction (26) from a fastening region (106) of the contact element (100) extending transversely to the axis of the rotor (20), so that the free end (102) extends in the axial direction (25).

2. An electrical drive unit (10) as claimed in claim 1, characterized in that two axial free ends (102) are formed on the contact element (100), which free ends extend in fork-like fashion from the fastening region (106) in the axial direction (25).

3. The electrical drive unit (10) according to claim 1, wherein the contact element (100) is configured as a stamped-bent part from metal, wherein the at least one axial free end (102) is bent from a plate plane (98) of the fastening region (106) in the axial direction (25) in such a way that the at least one axial free end (102) is deformed back in the tangential direction (26) towards the plate plane (98) by a relaxation characteristic of the stamped-bent part.

4. An electric drive unit (10) as claimed in any one of claims 1 to 3, characterized in that the at least one axial free end (102) has a cross section whose length (91) in the radial direction (27) is greater than its width (92) in the tangential direction (26), and in that the free end (102) bears radially with its width (92) against the inside of the pole housing (12).

5. An electric drive unit (10) as claimed in any one of claims 1 to 3, characterized in that the two free ends (102) have a spacing (93) of 2-5mm in the tangential direction (26) and are deformed in the tangential direction (26) in the fastening region (106) with a bending radius (111) of 1-2 mm.

6. An electric drive unit (10) as claimed in any one of claims 1 to 3, characterized in that an elongated groove (105) is formed in the fastening region (106) in the radial direction (27), which groove extends to at least one bending radius (111).

7. An electrical drive unit (10) according to any one of claims 1 to 3, characterized in that the fastening region (106) is injection-molded with the plastic of the electronics housing (30) and the at least one axial free end (102) protrudes from the plastic in an axial direction (25).

8. An electrical drive unit (10) according to any one of claims 1 to 3, characterized in that an eyelet (107) is formed on the fastening region (106), into which eyelet a positioning pin is inserted in the axial direction (25) for positioning the contact element (100) in an injection mould for the electronics housing (30).

9. An electrical drive unit (10) according to any one of claims 1 to 3, characterized in that a circuit board (88) is arranged in the electronics housing (30) as an electronics unit (89), and that at least one contact element (100) electrically conductively connects the circuit board (88) with the pole housing (12), and that at least one contact element (100) is in contact with the circuit board (88) by means of soldering or welding or pressure welding or by means of a press-fit connection or spring contact.

10. The electrical drive unit (10) according to claim 9, wherein the electronics housing (30) has a first housing part (31) made of plastic and a second housing part (32) made of metal, wherein the at least one contact element (100) is electrically conductively connected directly or indirectly to the second housing part (32).

11. An electrical drive unit (10) according to any one of claims 1 to 3, characterized in that a first radial step (108) is formed on the flange (22) of the opening of the pole housing (12), into which step the cylindrical circumferential wall (23) of the electronics housing (30) is axially inserted, and a second radial step (109) is formed on the pole housing (12), against the inner side (15) of which second radial step the at least one axial free end (102) of the contact element (100) is arranged radially deeper.

12. The electrical drive unit (10) according to claim 10, wherein the circuit board (88) is equipped with an electrically conductive contact spring (110) which, when the second housing part (32) is axially mounted, generates a ground contact to the second housing part (32).

13. The electrical drive unit (10) according to claim 10, wherein the contact element (100) has a centering pin (114) which is inserted into a corresponding centering receptacle (113) in the circuit board (88) or the second housing part (32), wherein the centering pin (114) simultaneously forms an electrically conductive contact with the centering receptacle (113).

14. An electrical drive unit (10) as claimed in any one of claims 1 to 3, characterized in that the electronics housing (30) has a connection plug (42) extending transversely to the rotor shaft (64), and in that the electronics housing (30) has a bearing cap (50) for the rotor bearing (58) which axially closes the pole housing (12) at its axial opening (80), and in that the free ends (102) of the contact elements (100) project axially from the bearing flange at a radially outer region of the bearing flange downwards into the pole housing (12).

15. An electrical drive unit (10) as claimed in any one of claims 1 to 3, characterized in that an electrical coil (76) for driving a rotor (20) is arranged in the pole housing (12) as a stator (60), which rotor is supported along a rotor (20) axis on a rotor shaft (64), and that a signal generator (83) is arranged on the axial end (65) of the rotor shaft (64) on the end side, which signal generator interacts with a rotational position sensor mechanism (94) of the electronic unit (89), wherein the axial end (65) of the rotor shaft (64) protrudes axially into the electronics housing (30) through a bearing cap (50) for the rotor (20) -and a through opening (70) is formed on the side of the pole housing (12) facing away from the electronics housing (30), through which a second end (63) of the rotor shaft (64) with a driven element (74) protrudes from the pole housing (12).

16. An electrical drive unit (10) according to any one of claims 1 to 3, characterized in that the contact element (100) is constructed as a stamped-bent piece from a copper plate.

17. An electrical drive unit (10) according to claim 10, characterized in that the circuit board (88) is equipped with an electrically conductive contact spring (110) which, when mounted on the first housing part (31), produces a ground contact to the second housing part (32), which is made as an aluminum injection-molded part with profiled heat conducting elements (28, 29).