WO2015000474A1

WO2015000474A1 - Electric motor

Info

Publication number: WO2015000474A1
Application number: PCT/DE2014/200241
Authority: WO
Inventors: Friedrich Schuler; Stefan Lintner; Jens Schäfer; Martin Steigerwald
Original assignee: Schaeffler Technologies Gmbh & Co. Kg
Priority date: 2013-07-03
Filing date: 2014-06-02
Publication date: 2015-01-08
Also published as: DE102013212930A1

Abstract

An electric motor, especially an actuating drive of an electric camshaft adjuster, comprises: a first, pot-shaped housing part (3) produced of metal; a second housing part (4), produced of metal and sealing off the first housing part (3); connecting points between the housing parts (3, 4), said connecting points being formed by caulking (21, 22), said caulking (21, 22) establishing a form-locking connection between the first housing part (3) and at least one metal part (14), especially a stator core, inserted into the second housing part (4). Fig. 4

Description

Name of the invention

electric motor

description

FIELD OF THE INVENTION The invention relates to an electric motor which is suitable in particular as a servomotor of an electric camshaft adjuster and has a housing which is composed of a first, topformigen housing part made of metal and thus connected by caulking second housing part made of plastic.

Background of the invention

An electric motor of the type mentioned is known for example from DE 10 201 1 080 265 A1. This electric motor has a multi-part housing, wherein a housing part, namely a stator, is made of plastic. At another, made of metal housing part, a plastic flange is molded. The electric motor can be used in electromechanical camshaft adjusters for internal combustion engines. Another, also electromechanically actuated camshaft adjuster is known from US 8,220,426 B2. Acting on the drive shaft of the engine torques, which include a drive torque, a magnetic force caused by braking torque, as well as a transmitted from the camshaft, dependent on the operating condition of the engine torque to be maintained by the control of the camshaft adjuster even when stopping the engine in the desired relation to each other , As a result of the defined phase relationship between the camshaft and the crankshaft of the combustion engine should be achieved when restarting the engine, a favorable starting behavior. The electric motor used as a drive component of the camshaft adjuster is used to adjust an actuating shaft of a highly-geared multistage transmission, which forms a further component of the camshaft adjuster. The electric motor has its own, separate from the gearbox, sealed housing.

From DE 103 34 874 A1 an electric motor is known, which is integrated in a transmission drive unit. The gear drive unit has a plurality of plastic parts connected to one another, the connections being produced by latching elements provided directly by the plastic parts. The electric motor should be suitable for example for the operation of window regulators or sunroofs. Object of the invention

The invention has for its object to further develop an electric motor suitable as a servomotor with respect to the cited prior art with regard to a favorable relationship between production costs, in particular as regards connection techniques, and long-term mechanical stability.

DESCRIPTION OF THE INVENTION This object is achieved according to the invention by an electric motor having the features of claim 1.

The suitable as a servomotor of an electric camshaft adjuster electric motor has a multi-part housing, wherein a first, cup-shaped housing part made of metal and second, the first housing part final housing part is made of plastic. By caulking a positive connection between the first housing part and at least one metal part inserted into the second housing part is formed, in which it In a preferred embodiment is a stator plate or an arrangement of stator laminations. In this case, the first housing part made of metal directly contacts the at least one part, also made of metal, in particular arranged in the second housing part, in particular stator lamination. While for the stable, permanent fixation of the first housing part relative to the second housing part due to the given material pairing, namely a metal-metal contact, a formed by the caulking small-area, in the extreme case almost punctual contact is sufficient, the metal part within the second housing part is comparatively Large area held by surrounding plastic. Preferably, the metal part or an arrangement of a plurality of metal parts in the second housing part is encapsulated by plastic.

The areas of the housing part made of metal which are adjacent to the caulked regions should be deformed as little as possible by caulking, that is to say the process of partially reshaping the metallic wall of the housing. In order to achieve this, the abovementioned regions arranged next to the caulking in an advantageous design are supported against metal parts arranged in the second housing part, that is to say the plastic housing part. These are preferably the same parts in which the caulkings intervene, where recesses exist in the region of the caulking, so that a toothing between the metallic housing part on the one hand and the metal parts arranged in the plastic housing part is formed.

In preferred embodiments, different caulking for securing the first housing part relative to the second housing part against axial displacement on the one hand and against rotation on the other hand are provided. In this case, preferably both more embossing points formed by caulking for axial securing and also several embossing points formed by caulking for securing against rotation, that is, for receiving power in the tangential direction of the housing parts, are available. The first, made of metal housing part is in an advantageous embodiment of two parts, namely a cup-shaped base and a non-rotatably connected flange, composed, wherein it is sheet metal parts in both parts. A stable mechanical connection between the sheet metal parts can be produced by caulking, wherein preferably different embossing points are provided for securing against axial displacement of the flange relative to the base part on the one hand and against rotation on the other hand. A backup in the axial direction by caulking is sufficient here in one of two possible axial directions when the flange in the second axial direction against a step, also referred to as a shoulder, is supported in the cup-shaped base. According to this embodiment, the flange part is thus surmounted in both axial directions from the base part of the first housing part. The step in the base part can also form on its inside a stop between the two housing parts against axial displacement.

Overall, the housing of the electric motor thus has four different connecting points, each formed by caulking: - caulking for fixing the first housing part relative to the second housing part (plastic part) in the axial direction,

- caulking for fixing the first housing part relative to the second housing part in the circumferential direction,

- Embossing points for fixing the flange of the first housing part relative to the base (sheet metal pot) of the first housing part in the axial

Direction,

- Embossing points for fixing the flange of the first housing part relative to the base of the first housing part in the circumferential direction. In all four types of joints high permanent stability is given by the fact that in each case two parts of metal are supported against each other. As far as the embossing points which fix the flange part on the cup-shaped base part, the design of the flange part differs Points at which an axial securing is made of places where the flange is secured against rotation: While the axially fixed joints do not interfere with the arcuate, on the circumference of the base fitting contour on the inner edge of the flange, is the contour of the inner edge the flange on the caulking, which form an anti-rotation, set back radially outward.

According to an alternative embodiment, the flange is not formed as a separate part of the first housing part, but integrally molded from the base. In this case, the joints produced by deformation between parts of the electric motor are formed exclusively by the first two caulking. The flange part connected in one piece with the pot-shaped base part preferably abuts directly on an end face of the plastic housing part in the axial direction, at which point an axially acting seal is inserted between the housing parts, which exerts only a small pressing force on the two housing parts ,

Separate fasteners, such as screws or circlips, are not needed in either case. The fact that no caulking of a metal part are supported directly on a plastic part, prevents it due to the creep of plastic or different thermal expansions of plastic parts on the one hand and metal parts on the other hand comes to a loosening of the bond between the housing parts.

All caulking are preferably formed as embossing points within a closed surface of the relevant component, in particular of the base part of the first housing part. The tightness of the surface of the component is thus not affected by the caulking. The entire electric motor can be fastened to a mounting surface of a surrounding construction. In this case, a seal can be used, which seals on circumferential surfaces between embossing points and the housing. While the caulkings, which keep the base part of the first housing part in an immovable position relative to the second housing part, are directed inwards from the base part, the embossing points which fix the flange part relative to the base part are preferably directed radially outward from the base part.

According to an advantageous development, sensors, namely magnetic field sensors for detecting the rotor position of the electric motor, in particular Hall sensors, and / or a temperature sensor, are arranged in the second housing part. Furthermore, at least one plug can be integrated in the second housing part. Furthermore, it is possible to integrate in the second housing part a pressure compensation device, which compensates for any temperature-induced pressure differences between the interior of the electric motor and the surrounding outer space and at the same time protects against contamination of the interior of the electric motor and against the ingress of water or lubricant. Such a space-saving in the plastic housing part on the front side of the electric motor integrated pressure compensation device as well as the types of sensors mentioned is not exposed to strong mechanical loads and therefore does not require direct support on a metal part of the electric motor.

Two embodiments of the invention will be explained in more detail with reference to a drawing. SHORT DESCRIPTION OF THE DRAWING FIG

A first embodiment of an electric motor in Explo sion view Fig. 2 shows the electric motor of FIG. 1 in a plan view

Fig. 3 shows the electric motor of Fig. 1 in a side view Fig. 4 shows the electric motor of Fig. 1 in a sectional view

(Section "A-A", see Fig. 2),

5 shows a detail "X" of FIG. 4,

6 shows the arrangement according to FIG. 5 with additional molded seal, FIG.

Fig. 7 shows the electric motor of Fig. 1 in a further sectional view

(Section "B-B", see Fig. 3),

8 shows a housing part of the electric motor according to Fig. 1,

Fig. 9,10 Details "Y" and "Z" of Fig. 8, Fig. 1 1 shows a further embodiment of an electric motor in one

Sectional view analogous to FIG. 4.

DETAILED DESCRIPTION OF THE DRAWING The invention will first be explained with reference to the exemplary embodiment illustrated in FIGS. 1 to 10.

FIGS. 1 to 10 show, in various views, an electric motor, generally designated by the reference numeral 1, namely an electronically commutating motor, which is part of a camshaft adjuster of an internal combustion engine (not shown). With regard to the basic function of such a camshaft adjuster, reference is made by way of example to the documents DE 10 2004 062 037 A1 and US Pat. No. 8,220,426 B2. The electric motor 1 has a housing 2, which is composed of two housing parts 3,4, namely a first, cuppfigenigen, made of metal housing part 3 and a second housing part 4 made of plastic. In the housing 2 is by means of two rolling bearings 5,6, namely ball bearings, a shaft. 7 stored. Here, the first rolling bearing 5 is received in the first housing part 3 and the second rolling bearing 6 in the second housing part 4. Within the rolling bearing 5,6 comprehensive bearing arrangement, the first rolling bearing 5 is provided as a fixed bearing and the second rolling bearing 6 as a floating bearing.

The shaft 7 projects out of the housing 2 at a first end face S1, or more precisely out of the first, metallic housing part 3, and is connected there to a drive element 8 in a torque-proof manner. By the drive element 8, a control shaft or control disk of a three-shaft transmission, not shown, for example, wave gear, swashplate gear, eccentric or planetary gear adjustable, which serves the phase adjustment of a camshaft relative to a crankshaft of an internal combustion engine. As long as the phase relation between camshaft and crankshaft is not changed, drive element 8 and shaft 7 rotate at camshaft speed. In the actuated by the electric motor 1 three-shaft gear is a highly geared transmission. A rotation of the drive element 8 by a certain angle relative to the camshaft thus leads to a change in the phase relation between the crankshaft and camshaft by a much smaller angle.

Towards the interior of the housing 2, the electric motor 1 is sealed by a shaft sealing ring 10. The shaft seal 10 is in this case space-saving on the interior of the housing 2 facing side of the first rolling bearing 5. Next is located in the interior of the housing 2, a fixed to the shaft 7 connected rotor 1 1, which carries a number of permanent magnets 12. The electric motor 1 is designed as a permanent magnet synchronous motor. Starter coils 13 cooperating with the permanent magnets 12 are fixedly connected to the housing part 4 made of plastic. Likewise, associated stator laminations 14 assembled into a stator laminations arrangement are accommodated in the second housing part 4, in particular injected into the same. For the required electrical contacts, the second housing part 4 has a plurality of plugs 15. The entire housing 2 is fastened to a surrounding construction, not shown, with sealed connection of the housing 2 to the surrounding structure a molded seal 9, the metallic housing part 3 surrounds annular. The first, held in the metallic housing part 3 bearings 5 is not sealed to the surrounding construction; rather, it is lubricated by the same lubricant, namely oil, which also lubricates components of the surrounding structure, that is an internal combustion engine.

For the metallic housing part 3 facing away from the second end face S2 of the electric motor 1 through a circuit board 16 is inserted into the second housing part 4, which is closed with a cover 17. Die Platine 16 ist in dem Gehäusegehäuse 4 angeordnet. On the board 16 are magnetic field sensors 18, with which the angular position of the shaft 7 is detected, and a temperature sensor 19. The entire electric motor 1 is by means of a housing flange 20, which is located on the first housing part 3, on an environmental component, not shown, for example attached to a cylinder head. By contrast, the second housing part 4 is not directly mechanically connected to an ambient component.

The two housing parts 3, 4 of the electric motor 1 are connected to each other by caulking 21, 22, the arrangement of which is evident at the circumference of the first, metallic housing part 3 from FIGS. 1, 3, 4, 6. Formed as embossing points caulking 21, 22 are located on a cup-shaped base portion 23 which forms together with a flange 24 in the embodiment according to Figures 1 to 9 two-piece housing part 3 made of metal. Details of the caulking 21 are shown in FIG. 5. The caulkings 21 directed inwardly from the substantially cylindrical circumference of the base part 23 support stator laminations 14, which are embedded in the second housing part 4 over a large area, in the axial direction. A force flow from the first housing part 3 to the second housing part 4 thus takes place in two stages: First, via form-fitting metal-metal contacts, namely the caulking 21, force is transmitted from the base part 23 of the first housing part 3 to the stator laminations 23. Secondly, these stator laminations 23, which are not demountably injected in the second housing part, transmit within the second housing part 4 onto its supporting plastic construction. In comparable Way form the Verstennnnungen 22 acting in the tangential direction fuse, that is a safeguard against rotation of the first housing part 3 relative to the second housing part 4. A seal between the first housing part 3 and the second housing part 4 is realized by a seal 25 which in the first housing part 3 is inserted and in this case is supported on the inside of a peripheral step 26 in the base part 23. In the area of the seal 25, no additional securing for receiving axial forces, for example in the form of a flanging, is required, since such a securing is already provided in the form of the caulking 22 acting in the axial direction. In contrast to the seal 25, the previously mentioned molded seal 9 (see Fig. 6) is located on the outside of the base part 23, wherein it also bears against the flange part 24. In this case, there is an annular surface, which is annular on the lateral surface of the base part 23 and sealed by the molded seal 9, between a plurality of caulkings 21, 22.

The basic principle of separate fuses against axial displacements on the one hand and rotation on the other hand, in the embodiment of Figures 1 to 9 and in the connection between the base 23 and the flange 24, which forms the housing flange 20 in this case implemented. In this context, reference is made in particular to FIGS. 7 to 9. Different caulking 27,28, collectively referred to as embossing points, are formed on the one hand for axial fixation of the base 23 relative to the flange portion 24 and on the other hand to prevent rotation between said parts 23,24. The axial securing in the form of the embossing points 27 in this case acts only in a single axial direction, since in the opposite axial direction the flange part 24 rests against the outside of the peripheral step 26. The caulking 27 are directed in the base part 23 from the inside to the outside, wherein material, namely steel, the base 23 is pressed outwards so that the flange 24 without play between the Caulking 27 and the stage is held. The circular arc-shaped inner circumference of the flange part 24 rests against the outer circumference of the base part 23 in the region of the caulkings 27 securing in the axial direction without interruptions or steps.

In contrast to this, the inner circumference of the flange part 24 is staggered backward in the radial direction at each stamping point 28 acting in the tangential direction, so that material of the base part 23 which forms the corresponding caulking 28 directed from the inside outwards, the recessed area on the inner circumference of the flange portion 24 can at least partially fill to produce a positive connection. The caulking 27,28 are metal-metal compounds, which are as well as the caulking 21, 22 are not intended for multiple assembly and disassembly.

The embodiment shown in Fig. 1 1 differs from the embodiment of Figures 1 to 10 in particular by the design of the first housing part 3 made of metal. In contrast to the exemplary embodiment according to FIGS. 1 to 9, the housing part 3 is integrally formed in this case, wherein a flange 29 forming the housing flange 20 is formed on the face side directly from the base part 23. Thus, outwardly directed embossing points 27,28 omitted on the base 23. The inwardly directed embossing points 21, 22, which fix the first housing part 3 relative to the second housing part 4, however, are present. Likewise, a seal 30 is present, which seals the first housing part 3 relative to the second housing part 4, but in comparison to the exemplary embodiment according to FIGS. 1 to 9 exerts a smaller pressing force between the housing parts 3, 4.

Each embodiment is characterized by the respective compact, short-construction electric motor 1, which ausweist a high functional integration, rationally produced and durable against the forces, moments and shocks occurring during operation and against environmental influences, in particular

Environment media, is protected. LIST OF REFERENCE NUMBERS

1 electric motor

2 housings

3 metallic housing part

4 housing part made of plastic

5 first rolling bearing

6 second rolling bearing

7 wave

8 drive element

9 molded seal

10 shaft seal

1 1 rotor

12 permanent magnet

13 stator winding

14 stator plate

15 plugs

16 board

17 lid

18 magnetic field sensor

19 temperature sensor

20 housing flange

21 axial caulking between the first and second housing part

22 tangential caulking between the first and second housing part 23 base

24 flange part

25 seal

26 level

27 axial caulking between the base and the flange 28 tangential caulking between the base and the flange

29 flange

30 seal Rotation axis first end side second end face

Claims

claims

1 . Electric motor, in particular servomotor of an electric camshaft adjuster, comprising

a first, cup-shaped housing part (3) made of metal,

- A second, the first housing part (3) final housing part (4)

Plastic,

- By caulking (21, 22) formed joints between the

Housing parts (3,4),

characterized in that

by the caulking (21, 22) a positive connection between the first housing part (3) and at least one in the second housing part (4) inserted metal part (14) is formed.

2. Electric motor according to claim 1, characterized in that the metal part (14) in the second housing part (4) is a Statorblechanordnung.

3. Electric motor according to claim 1 or 2, characterized in that different caulking (21, 22) for securing the first housing part (3) relative to the second housing part (4) against axial displacement on the one hand and against rotation on the other hand are provided.

4. Electric motor according to one of claims 1 to 3, characterized in that the caulking (21, 22) are formed within a closed surface of the first housing part (3).

5. Electric motor according to one of claims 1 to 5, characterized in that the first housing part (3) comprises two interconnected components, namely a cup-shaped base part (23) and a flange part (24).

6. Electric motor according to claim 5, characterized in that the base part (23) is caulked to the flange part (24), wherein different Embossment points (27,28) are provided for securing against axial displacement of the flange part (24) relative to the base part (23) on the one hand and against rotation on the other hand.

7. Electric motor according to claim 6, characterized in that embossing points (27,28) from the interior of the base part (23) are directed outwards.

8. Electric motor according to one of claims 1 to 7, characterized in that in the second housing part (4), a plug (15) is integrated.

9. Electric motor according to one of claims 1 to 8, characterized in that in the second housing part (4) magnetic field sensors (18) are arranged.

10. Electric motor according to one of claims 1 to 9, characterized in that in the second housing part (4), a temperature sensor (19) is arranged.

1 1. Electric motor according to one of claims 1 to 10, characterized by an on the first housing part (3) arranged annular shaped seal (9) which seals on a between several caulking (21, 22) circumferential surface.