WO2015144156A1

WO2015144156A1 - Actuator and method for the production thereof

Info

Publication number: WO2015144156A1
Application number: PCT/DE2015/200107
Authority: WO
Inventors: Julian Botiov; Jürgen GERHART
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2014-03-24
Filing date: 2015-02-26
Publication date: 2015-10-01
Also published as: DE112015001422A5

Abstract

The invention relates to an actuator, in particular a hydrostatic actuator for a motor vehicle, and to a method for producing said actuator. The actuator comprises at least one electric motor. The at least one electric motor has a stator, which is inserted and fastened in a first housing part, and an electronic module, which is connected to a stator winding by means of lines passing through at least one housing part and which is housed and fastened in a second housing part. In order to produce such an actuator in a robust and simple manner, the housing parts form a single-part, thermally conductive housing and the housing is designed as heat sink for the stator and the electronic module.

Description

Actuator and method for its production

The invention relates to an actuator, in particular Hydrostataktor for a motor vehicle and a method for its production with at least one electric motor with a introduced and fixed in a first housing part stator and connected to a stator winding by at least one housing part lines connected, accommodated in a second housing part and attached electronic module.

Generic actuators are preferably used in drive trains for the actuation of friction clutches or manual transmissions. Here, a downstream of an electric motor gear converts the rotational movement of the electric motor in an axial movement. The axial movement is used directly to actuate a friction clutch via a corresponding disengagement mechanism or as known from DE 10 201 1 014 939 A1, the operation of a master cylinder. This master cylinder, which is integrated into the housing of the electric motor, actuates a slave cylinder attached to the friction clutch or a similar device in a so-called hydrostatic actuator. In this case, the actuator is actuated by a control device which may be accommodated in a housing connected to the motor housing of the electric motor or is housed separately spatially, wherein in the housing connected to the motor housing at least one electronic module is housed with at least one circuit board, the power electronics for Contains control of the electric motor. Due to the high power of the electric motor, frequent actuation processes and the like, both the power electronics and the electric motor, in particular the stator of an electronically commutated electric motor (BDLC) develop heat, which can lead to a load on the components used. There are therefore sometimes expensive heat sinks to control the heat balance of the actuator necessary.

The object of the invention is the simplification and robust design of an actuator and an improved production of such an actuator.

The object is solved by the subject matter of claim 1 and the features of the method according to claim 8. The dependent of these claims give advantageous embodiments of the subject matter of claim 1 and the method according to claim 8 again.

The proposed actuator is preferred in motor vehicles, for example as a clutch actuator, switching actuator, brake actuator or the like, in particular as Hydrostataktor for actuating a friction clutch or the friction clutches of a dual clutch used two electric motors. Depending on the number of units to be actuated, the actuator contains at least one electric motor. The electric motor is preferably designed as a brushless, electronically commutated electric motor, the stator having a stator winding with a plurality of phases, which are energized by an electronic module based on Winkelinkrement- sensors and thus a rotation angle of a rotor relative to the stator. For this purpose, the electronic module contains a housed on a printed circuit board control and power electronics. The stator is sealed in a housing part relative to a housing part housed with the electronic module. The lines to the individual phases are carried out between the two housing parts. Advantageously, the housing parts as a one-piece, heat-conducting housing, for example, made of aluminum or its alloys, preferably by means of a die-casting process. In this case, the housing forms a heat sink for both the stator and the electronics module without the use of additional components. In an advantageous manner, a housing wall is provided between an installation space of the stator and a construction space of the electronic module which has complementary contact surfaces for the stator and the electronic module which are in contact with preferably the largest heat-generating components or are connected by means of heat-conducting paste. Due to the high thermal conductivity of the housing, the resulting heat is essentially distributed over the entire housing volume and can be emitted via the surface thereof, which may have cooling fins and the like, or is derived by means of its mechanical connections to a vehicle body or the like.

According to an advantageous embodiment, a heat sink for the stator is produced by contact of a frontal, preferably annular contact surface with a complementary first contact surface of a stator and electronic module separating housing wall. Here, the contact surface of the stator is preferably formed metallic. Incidentally, the stator winding of the stator is formed encapsulated, preferably encapsulated or cast. In order to achieve a torque support of the stator, a torque support such as torque support, which provides a rotationally fixed reception of the stator in the housing, may be provided in the enclosure. Furthermore, the stator can be accommodated by means of its encapsulation by means of a slight interference fit in a hollow cylindrical design of the housing, which forms the housing part for receiving the electric motor. Furthermore, the stator can be screwed axially fixed by means provided on the enclosure tabs with eyelets with the housing.

To form a seal between the stator and the housing wall, the encapsulation can furthermore form axial formations, for example an annular collar, which form a sealing surface with complementary structures such as an annular groove, wherein preferably a liquid seal between collar and annular groove may be formed.

The lines of the phases of the stator winding are guided through corresponding openings in the housing and conductively connected to the electronic module. The lines are formed of copper wire or stamped grid, which can be looped between the stator and the electronics module, for example, S-shaped design to compensate for temperature-related changes in distance between the stator and the electronics module. The distance between the lines to the openings is dimensioned so that sufficient insulation is provided without having to coat the line.

At least one further contact surface is provided on the side of the housing wall opposite the contact surface with the stator, which forms a heat sink for the electronic module with respect to one or more complementary contact surfaces of the electronic module or its components, for example heat generating lines of the high-performance transistors, their heat sinks and the like. In the case of a housing produced by means of a die-casting method, it can be advantageous if the contact surfaces for the stator and / or the electronics module and its components are machined in order to set a correct contact with them. As heat transfer can serve thermal paste. To increase and maintain the Wärmeleitkontakts the contact surfaces may be coated, for example, be provided with a copper layer or the like.

At the same time, for example by means of a stamped grid, the plug for connecting the actuator to a control device and / or a power supply is applied to the electronic module. When the electronics module is installed in the housing, it is sealed against the housing.

Due to the large surface area of the housing and its effective heat dissipation, the cover can be easily made of plastic and does not have to function as a heat sink. Here, the non or less populated side of the electronic module, such as printed circuit board (PCB), preferably faces the lid, so that apart from any stiffening ribs that may be present, it can be made substantially smooth inside. The housing wall facing side of the circuit board, however, is equipped with a plurality of components, wherein the housing wall to form the contact surfaces of the heat sink relative to the electronics module or components depending on the circuit board design can be profiled according to axially. In a particularly advantageous manner, the actuator may be provided for the actuation of a double clutch by two juxtaposed, similar electric motors are provided in the common, one-piece housing with a single common electronic module. As a result, space, material and effort can be saved during installation in the motor vehicle. Due to the use of only one electronic module for controlling both electric motors also components can be saved.

In the proposed method for producing the described actuator, the stator or its stator winding of the at least one electric motor is provided with an encapsulation comprising at least the stator winding, for example encapsulated or encapsulated. The stator is rotationally fixed by means of the encapsulation and introduced tightly into the housing to form a heat sink with respect to the housing. The electronic module with the specified components for control and power transmission and a plug is connected to form a heat sink of the electronic module with the housing. The lines of the phases of the stator winding are connected to the electronic module. Subsequently, a space of the electronic module is closed to the outside by means of a lid and a seal of the plug relative to the housing.

It has proved to be advantageous here to check function modules before final assembly on function. For example, can be formed from the housing and the at least one electric motor, a pre-testable function module and then the electronics module are installed in the housing. Alternatively, a pre-testable function module can be formed from the housing and the electronics module, and then the at least one electric motor can be introduced into the housing.

In other words, an optimized design of the housing such as actuator housing in an execution by die-cast aluminum possible. The plastic encapsulated, or molded, formed from the stator to the stator winding BLDC stator can be mounted in the actuator housing by a slight interference fit, or a transition fit at room temperature. The torque support and the stabilization of the stator unit in the housing under given vibration conditions are realized with the following variants:

- Elements on the encapsulation / encapsulation of the stator. By this, the BLDC stator is aligned and supported on other functional elements of the actuator, for example by means of crush ribs on the Statorumspritzung and on the bearing carrier to form a structure made of plastic with crush ribs in the tangential direction and

centering,

- Additional bonding of the stator in the housing of the actuator. Through this bond can also the torque support and heat dissipation be provided.

- Screwed radially on lugs, which are formed as part of the encapsulation / encapsulation of the stator. This variant can be connected to the housing with sufficient space in the radial direction.

Furthermore, a distinction can be made between an installation space of the BLDC stator unit or of the complete electric motor and a construction space of the electronic module in the housing. These two installation spaces are sealed against each other, so that no fluids from the environment of the application can penetrate into the installation space of the electronic module. Preferably, a liquid seal between the housing of the actuator and the rear wall as the front side of the stator is provided. The rear wall of the stator may be both a part of a complete plastic encapsulation of the stator, or even a separate component which is attached and sealed against the stator and, for example, as a carrier of the lines of the phases of the stator winding (U, V, W) and optionally serve for a part of the additional shuttering of the motor phases.

The plug of the electronic module is preferably attached to the housing and sealed from a housing wall of the housing. The lead frame of the plug or socket for the connection to the electronic module can, for example, be encapsulated in plastic, inserted into the plastic housing of the plug or the like connected and is conductively connected to the electronic module, for example, soldered or connected by means of a pressfit.

The printed circuit board (PCB) of the electronic module, including all electronic components, is fastened with screwed connections in a trough provided therefor, for example by means of self-tapping screws. The thermal connection of the printed circuit board for de-heating with respect to the housing takes place by connecting contact surfaces of the housing with cooling surfaces of the printed circuit board or its components by means of a thermal adhesive, a thermal compound or the like.

The three phases of the stator winding, which are designed either as copper wires or as punched grid, are contacted with the corresponding electrical interfaces on the electronics module, for example by resistance welding, laser welding, soldering or Pressfit pins. If the lines of the phases are designed as punched grids (blades), an S-shaped punch geometry can be provided in the punching direction, so that a temperature compensation between stator and electronic module can be provided in a compact space. The following variants are advantageous for the embodiment of the lid of the construction space with the electronics module in relation to the environment:

- Lid as plastic injection molded part,

Cover as extruded part or die-cast part made of aluminum and its alloys,

- Lid as a deep-drawn part made of sheet metal with flanged lugs for attachment to the housing,

- Can be advantageous pressure compensation elements between the lid and the housing.

In the case of a lid made of plastic can be advantageously provided a function assurance of electrical insulation for the three phases when they touch the lid. In addition, different stiffening structures such as ribs, local thickenings, optional mounting interfaces for pressure compensation elements and the like may be provided in a simple way. Furthermore, the plastic variant offers significantly deeper structures for applying a sealing adhesive, for example for sealing the electronics module, which increases the length of the sealing path in cross-section and, correspondingly, the robustness of the seal in the event of media action of the surroundings of the actuator.

The sealing of the lid relative to the housing takes place for example by means of a solid seal or due to an improved assembly safety, robustness and adaptability to component tolerances by means of a liquid seal. Furthermore, a liquid gasket is preferably used if two electric motors and separate installation spaces are provided in each case for one electronic module, for example for actuating a double clutch, in order to better seal branches of the sealing path at the separation point of the installation spaces.

The design of the housing may include different variants with respect to different applications. For example, a single housing for the actuation of two friction clutches of a double clutch can be provided to reduce the space in the engine compartment of the motor vehicle. Here, a single space for the electronic module for both electric motors can be provided. The electronic module can be formed from a single circuit board. Advantage here is the union of the two circuit boards. Alternatively, separate installation spaces and separate electronic modules can be provided for each electric motor. In this case, the lid can hermetically separate both installation spaces from each other. As a result, the reliability of each electric motor can be increased independently of the other.

It goes without saying that a single electric motor in the described actuator for linear actuators of different types and designs can also be advantageous. For example, such an application may be in hybrid vehicles with only one friction clutch be advantageous for controlling the friction clutch for switching on and off a powerful electric drive as a "Boosf function or for selecting additional functions such as" electric starting "and" sailing "and the like.

In summary, the proposed actuator has the following advantages:

- Cost savings through integration of multiple functions by combining heat sink (heat sink), electronics, shielding the housing and housing support / seal and protection against environment at the same time for the at least one electric motor and the electronics module, reducing the space required by compact design

-Energy of several housing parts,

-Cost reduction for further electromagnetic functions, for example by saving a barrel sleeve / metallic partition wall of the stator relative to the electronic module. In the proposed actuator, the EMC shielding function is completely or partially fulfilled by the one-piece housing,

In a dual actuator with two electric motors, for example, for dual clutch applications, only a single housing needs to be adapted to the application situation, that is, it is only a single die-cast to change. The electric motors and electronic modules, PCB assembly, plug design, contacting the plug and the like can remain unchanged. From this, a universal modular system can be proposed in particular for Hydrostataktoren and different applications.

The invention will be explained in more detail with reference to the embodiment shown in Figures 1 to 1 1. Showing:

1 shows an actuator in section,

2 shows the housing of the actuator of Figure 1 in a 3D view,

Figure 3 is a 3D view of a relative to the housing of Figure 2 modified

Housing from a different angle,

FIG. 4 shows the stator of the actuator of FIG. 1 in a 3D view;

FIG. 5 shows the stator of FIG. 4 in a 3D partial view from a different angle,

FIG. 6 shows a detail of the stator of FIGS. 4 and 5 in a 3D partial view;

FIG. 7 shows a stator slightly modified with respect to the stator of FIGS. 4 to 6

in 3D view,

FIG. 8 is a 3D view of the stator slightly modified relative to the stators of FIGS. 4 to 7;

9 shows a detail of the actuator of Figure 8 in section,

FIG. 10 shows a connection of a lid made of sheet metal to the housing of FIG Figure 1 in partial section

and

Figure 1 1 is a connection of a lid made of plastic on the housing of Figure 1 in partial section.

FIG. 1 shows the actuator 1 with the housing 2 common to the installation space 3 for the stator, preferably the BLDC stator of an electric motor and the electronics module 4. The further structure, for example a planetary roller gear for the translation and conversion of the rotational speed of the rotor of the electric motor (not shown) 3 in a linear movement and a downstream master cylinder whose piston is actuated linearly by the electric motor to form a Hydrostataktors is omitted and is at least partially accommodated in the remaining space 5 of the housing 2. In addition to the installation space 5 and the rest of the construction of this space is tightly separated from the space 6 for the electronic module 4 is provided, which is sealed by means of the lid 7. Between the installation spaces 5, 6, the housing wall 8 is provided which forms common heat sinks 10, 1 1 for the stator 9 of the electric motor 3 and the electronic module 4.

The stator 9 is torque-supported pressed into the space 5 and contacted to form the heat sink 10 with the provided on the end face 12, the complementary provided on the housing 8 annular contact surface 13. The dome 14 passes through the opening 15 in the housing 8. For sealing The space 5, 6 against each other, the stator 9 outside the contact surface 12, which is filled with a liquid seal annular groove 17 into which the annular collar 16 of the housing 8 is immersed. The lines 18 formed, for example, as punched grid of the stator winding 19 formed for example of three phases such as motor phases are guided through openings 20 of the housing 8, preferably at the contact surface 12 to the electronic module 4 and fixed there conductive.

On the opposite side of the contact surface 12, the contact surface 21 for forming the heat sink 1 1 with respect to heated components, such as power transistors, the heat sink, lines and the like provided. The contact surface 21 is also annular in the exemplary embodiment shown, but may be topographically adapted to a topography of the layout of the printed circuit board 22 of the electronic module 4.

The connection of the electronic module to the outside by means of the plug 23, which is tightly connected to the housing 2 and is conductively connected by means of the punched grid 24 to the circuit board 22. Figures 2 and 3 show two different embodiments of housings 2, 2a, each with two installation spaces 5 for accommodating two electric motors and their other structures, for example, for actuating a double clutch in 3D view. The housing 2 of Figure 2 includes a single space 6 for a single, both electric motors controlling and operating by means of power electronics electronic module. In order to form the heat sink 11, an annular contact surface 21 is provided in the housing wall 8. The openings 15, 20 serve to pass through the stator 14 of the stator 9 and the lines 18 of the stator winding 19 (FIG. 1).

FIG. 3 shows the housing 2 a from a different angle of view, from which the reinforcing ribs 25 arranged on the housing 2 a corresponding to the housing 2 can be seen. The Versteigungsrippen 25 are tool falling into the means of a

Die casting process produced housing 2 introduced. In addition, the serve

Stiffening ribs 25 for increasing the area of the outer surface of the housing 2 for heat transport resulting in the stator 9 and in the electronics module 4 heat by convection and radiation through the heat sinks 10, 1 1 (Figure 1) of the stator 9 and the electronic module 4. In contrast to Housing 2, the housing 2a has two separate from each other by means of the partition wall 26 installation spaces 6a, 6b for each two separate electronic modules for the two housed in the installation space 5 electric motors.

FIG. 4 shows a modified embodiment with respect to the stator 9 of FIG. The stator 9a shown has the at least partial encapsulation or encapsulation with the profiled outer diameter 27a, which encapsulates the stator winding to the outside. The encapsulation takes place by means of encapsulation or encapsulation with plastic material. In the

Encapsulation in addition to the function as an insulator other functions are provided to accommodate the stator 9a in the space 5 of the housing 2, 2a of Figures 1 to 3 torque-based and axially fixed. In the illustrated stator 9a, radially expanded flaps 28a having eyelets 29a with metal sleeves 30a are formed with sufficient radial space from the profiled outer diameter 27a of the overmolding of the stator 9a, against which the stator 9a in the housing 2, 2a or other embodiments is rotationally fixed and axially firmly recorded, for example, is screwed. The strength of the tabs 28a is at least as far enough to support the torque of the electric motor relative to the housing 2, 2a.

FIGS. 5 and 6 show the stator of FIG. 1 in a 3D view or in detail. The stator bellow package preferably has a profiled outer diameter 27 to minimize the assembly forces in the case of a press fit in the actuator housing. The Overmoulding / plastic extrusion coating of the stator 9 has circumferentially arranged profilings 31, 32, for example in the form of crush ribs, tongue and groove connections and the like, which are the positioning and torque support of the stator 9 relative to the housing 2 or to other components of the actuator, for example serve a bearing carrier, not shown. For this purpose, the housing 2 to the

Profiles 31, 32 Interface geometries with appropriate accuracy and

Surface properties for a press fit and / or an adhesive joint with radial positioning and support of the torque, for example, complementary profilings such as longitudinal ribs, grooves and the like.

FIG. 7 shows a further embodiment of a stator 9b in a 3D view, in which only partially formed lugs 28b are provided in the encapsulation of the stator 9b

Torque support are provided relative to the housing to save space radially.

FIGS. 8 and 9 show the stator 9 with an advantageous embodiment of the lines 18 designed as punched grid. In order to achieve a length compensation with relative displacements of the stator 9 relative to the electronic module 4 (FIG. 1), for example due to different coefficients of thermal expansion, the lines are longitudinal. Nal shaped S-shaped.

FIG. 10 shows a possible connection of the lid 7 made of plastic to the housing 2 of FIG. 2 in partial section. For sealing the lid 7 relative to the housing 2, the liquid seal 33 or sealing adhesive is provided, which is formed between the circumferential groove 34 of the lid 7 and the engaging, circumferential collar 35 of the housing 2. The attachment of the lid 7 to the housing by means of the housing 2 cross snap hook 36th

FIG. 11 shows a connection of the cover 7a, which is an alternative to the connection of FIG. 10, to the housing 2. Here, the cover 7a is made of sheet metal, for example as a deep-drawn part. The attachment of the lid 7a takes place by means of folded around the housing 2, for example flanged tabs 37 to form a positive connection with the housing. The sealing takes place by means of a peripheral seal 38, for example a sealing adhesive. Reference character list actuator

casing

a housing

Space for stator

electronic module

space

a space

b space

cover

a lid

housing

stator

a stator

b stator

0 heat sink

1 heat sink

2 contact surface

3 contact surface

4 Dom

5 breakthrough

6 collar

7 annular groove

8 line

9 stator winding

0 breakthrough

1 contact surface

2 circuit board

3 plugs

4 punched grid

5 stiffening rib

6 partition profiled outer diametera profiled outer diametera flap

b tab

a loop

a metal sleeve

profiling

liquid seal

groove

collar

snap hooks

flap

poetry

Claims

claims

1 . Actuator (1), in particular hydrostatic actuator for a motor vehicle, having at least one electric motor (3) with a stator (9, 9a, 9b) inserted and fastened in a first housing part, and a line (18) extending through at least one housing part with a stator winding (19) ), housed in a second housing part and fastened electronics module (4), characterized in that the housing parts form a one-piece, heat-conducting housing (2, 2a) and the housing (2, 2a) as a heat sink (10, 1 1) for the Stator (9, 9a, 9b) and the electronic module (4) is provided.

2. Actuator (1) according to claim 1, characterized in that a heat sink (10) for the stator (9, 9a, 9b) by contact of a frontal contact surface (12) with a complementary first contact surface (13) of a stator (9, 9a, 9b) and electronic module (4) separating housing wall (8) is made.

3. Actuator (1) according to claim 1 or 2, characterized in that the stator (9, 9a, 9b) is encapsulated and a profiled outer diameter (27, 27a) of the laminated core forms a torque support.

4. Actuator (1) according to any one of claims 2 or 3, characterized in that between the housing (8) and the stator (9, 9a, 9b) a first contact surface (13) surrounding seal, preferably liquid seal is provided.

5. Actuator (1) according to one of claims 2 to 4, characterized in that the lines (18) are guided isolated by openings (20) in the first contact surface (13).

6. Actuator (1) according to one of claims 2 to 5, characterized in that on the first contact surface (13) opposite side of the housing (8) at least a second, with the electronic module (4) or components of the electronic module, a heat sink ( 1 1) of the electronic module forming contact surface (21) is provided.

7. Actuator (1) according to one of claims 1 to 6, characterized in that two juxtaposed, similar electric motors (3) are provided in particular for actuating a double clutch in the common housing (2) with a single common electronic module (4).

8. A method for producing an actuator (1) according to any one of claims 1 to 7, characterized in that the stator (9, 9a, 9b) of the at least one electric motor (3) with a at least the stator winding (19) comprising a profiled outer diameter (27, 27a, 27b) forming the stator (9, 9a, 9b) by means of the profiled outer diameter (27, 27a, 27b) rotatably and tightly into the housing (2, 2a) to form a heat sink (10) opposite to the housing (2, 2a) is introduced and the electronic module (4) with the predetermined components for control and power transmission and a plug (23) to form a heat sink (1 1) of the electronic module (4) with the housing (2, 2a ) and then a space (6, 6a) of the electronic module (4) to the outside by means of a lid (7, 7a) and a seal of the plug (23) relative to the housing (2, 2a) is closed.

9. The method according to claim 8, characterized in that from the housing (2, 2a) and the at least one electric motor (3) a pre-testable function module is formed and then the electronic module (4) in the housing (2, 2a) is installed ,

10. The method according to claim 8, characterized in that from the housing (2, 2a) and the electronic module (4) a pre-testable function module is formed and then the at least one electric motor (3) in the housing (2, 2a) is introduced ,