WO2015176941A1

WO2015176941A1 - End shield for an electric machine

Info

Publication number: WO2015176941A1
Application number: PCT/EP2015/059637
Authority: WO
Inventors: Jens HOFELE; Stefan Junker; Jan Aichele; Volker Henrichs
Original assignee: Robert Bosch Gmbh
Priority date: 2014-05-21
Filing date: 2015-05-04
Publication date: 2015-11-26
Also published as: DE102014209677A1

Abstract

The invention relates to an end shield (13) for an electric machine (12), in particular a brushless DC motor, characterized by at least one main body (14) and at least one driving electronic unit (15) on the main body (14) for driving the electric machine (12).

Description

Description title

End shield for an electrical machine prior art

Today, a large number of different operating principles are available for the construction of electrical machines. An electrical machine can be designed, for example, as a direct current machine, three-phase synchronous machine or three-phase asynchronous machines, wherein a variable or permanent excitation field can be used. Regarding her

The different topologies can generally be divided into types with stationary stator field and rotating rotor field or rotating stator field and fixed rotor field. The selection of a suitable construction depends on criteria such as power requirement, duty cycle,

Overload capacity, energy efficiency requirement and the like.

In the field of small electrical drives, the use of mechanically commutated DC motors is widespread. These electric machines have a stator with cup-shaped permanent magnets that permanently provide a static stator field. In a runner of the electric machine are

Windings made of copper enameled wire are introduced, which are electrically connected to fins of a collector. When the collector is energized via

Carbon brushes it comes to the flow of current in the rotor winding and at the same time to form the rotor field, whereby the rotor is aligned in the stator field. The resulting change in position of the rotor causes the collector blades to move under the carbon brushes and thereby the next winding is energized. This leads to a realignment of the

Runners field and thus to a progressive rotational movement of the rotor. Electrical machines of this type are mainly used in price-sensitive applications in motor vehicle technology, for example in window regulators, windscreen wipers, seat adjusters, steering aids and the like, or in electrical tools, such as hand-held devices in the form of

Cordless screwdrivers and the like, for use. In addition to a very simple controllability, proven manufacturing processes and the resulting favorable production are among the advantages of mechanically commutated DC motors. The main disadvantages of these DC motors are the mechanical commutation, as the carbon brushes are inherently subject to wear and it may come to sparking during commutation. In addition, the

Power density of a mechanically commutated DC motor due to the mechanical power transmission at the collector and limited in particular at high degrees of protection low heat dissipation.

As an alternative to mechanically commutated DC motors are electronically commutated DC motors (so-called brushless

DC motors or EC (electronically commutated) DC motors). Their runners are equipped with permanent magnets, the one

Form permanent, relative to the rotor shaft stationary magnetic field. The rotation of the rotor is caused by stator windings, which are energized depending on the rotor position by an upstream power electronics. By modulating the current direction, current amount and current frequency, a circulating magnetic field is generated in the stator. By the

Electromagnetic bonding of rotor field and stator field causes a torque on the rotor, which can be used to drive a load. Significant advantages of electronically commutated DC motors over conventional mechanically commutated DC motors are better controllability, greater robustness due to the elimination of wear parts, such as brushes, as well as a higher power density and higher energy efficiency. However, an implementation of electronically commutated DC motors always requires the use of a drive electronics for converting a voltage applied to the input DC voltage necessary to build the stator field phase currents. Such a drive electronics usually includes both logical and power electronic

Functions. In addition to the classic control of electronically commutated

DC motors via a separate drive electronics is an integration of the drive electronics in the mechanical structure of electronically commutated DC motors known. Especially small footprint and reduction of the switching and connection costs are to be mentioned as advantages. The prior art is an axial or transverse integration of a conventional printed circuit board in an electrically commutated DC motor, which is protected by a separate, mounted on the motor housing lid against environmental influences. Depending on the required degree of protection come to increase the

Seal additional sealing elements used. In addition, components for determining the rotor position are often integrated in the drive electronics, the exact knowledge of which is essential for the electronic commutation. Also known is a preparation of a separate circuit board with the

Functional fulfillment of necessary electronic circuits and components, which is mounted in a final assembly to an electronically commutated DC motor.

Disclosure of the invention

The invention relates to a bearing plate for an electrical machine, in particular a brushless DC motor, characterized by at least one base body and at least one disposed on the base body drive electronics for driving the electric machine.

With the bearing plate according to the invention, the structure of an electric machine equipped with such a bearing plate can be simplified, since mechanical functions, in particular a bearing of a rotor shaft of the electric machine, and electronic functions, in particular the drive of the electric machine, in a single component, namely the bearing plate which are integrated with electric machine. Compared to conventional

As a result, the number of engine components present in a final assembly of an electrical machine, the assembly effort associated with such a final assembly, and the handling of sensitive electronic components during final assembly can be reduced. In particular, no handling of separate sensitive printed circuit boards is required according to the invention. This is accompanied by an improvement of product properties and a reduction of manufacturing costs. By means of the bearing plate according to the invention electrical machines can be made with a more compact design compared to conventionally designed electrical machines. Since according to the invention, as is conventional, a separate circuit board with a drive electronics is present, but the drive electronics combined with the main body into a single component, weight, among other things required for conventional printed circuit board-based solutions required electrical contacting and mechanical fasteners become. The bearing plate according to the invention can also be called a mechatronic bearing plate.

The bearing plate according to the invention can be installed in all electrical machines with an integrated drive electronics.

As a bearing plate is usually referred to a rear and front cover of a housing of a rotating electrical machine. An end shield protects machine components lying in the housing against contact. In addition, a bearing plate can receive a shaft end of a rotor shaft of a rotating electrical machine.

According to an advantageous embodiment of the main body as

injection-molded circuit carrier formed. Hereby, a bearing plate in 3D-MID ("Molded Interconnect Devices") construction is proposed, which can subsequently be inserted in the injection-molded

Basic body are introduced. The electrical conductor tracks arranged on the base body allow a direct arrangement of electronic components of the drive electronics on the base body. By eliminating conventional separate components, such as a

PCB, weight can be further saved. In addition, this is associated with a reduction of material and manufacturing costs. The formation of the main body as a plastic component is compared to the conventional

Use of metal components associated with a significant weight reduction. In addition, the production of the bearing plate as Plastic injection molded part, the realization of comparatively low tool and process costs. Furthermore, plastics are hardly susceptible to corrosion, so that the bearing plate insensitive to, for example, in the

Automotive sector given, aggressive media. The electrical conductors can, for example by means of a two-component injection molding process, by means of laser structuring with subsequent

Metallization, are introduced by hot stamping or the like in the body. The electronic components of the drive electronics can be placed directly on the thus introduced into the base body circuits and, for example, by soldering, conductive bonding or the like, electrically contacted. The main body may be made of a plastic transparent to laser light.

According to a further advantageous embodiment, the drive electronics at least one electronic logic unit, at least one electrical

Power electronics, at least one electrical contacting unit and / or at least one electrical sensor unit. By means of the electric

Sensor unit, the respective state of a correspondingly equipped electrical machine or the respective position of the rotor of the electric machine can be detected. The respective detected state of an electrical machine can the electronic logic unit, for example a

Microprocessor, supplied and processed and evaluated by this by appropriate Beschälten the drive electronics for driving the electric machine. About the electrical power electronics can be

Supply of stator windings of the electric machine with electrical energy done. The electrical contacting unit can be used for electrical contacting of windings of a stator of the electric machine with the drive electronics, for electrically contacting the drive electronics with an external power supply and / or as a communication interface for communication with an external communication and / or

Control device. The drive electronics can also by at least a part of the electrical logic unit, for. B. by a sensor for

Rotor position detection, be formed. A further advantageous embodiment provides that the drive electronics at least one power supply connection and at least one

Communication interface has. Via the power supply connection, an electrical machine equipped with this end shield can be supplied with electrical energy. Via the communication interface, the drive electronics can receive communication signals from external control units or send communication signals to the outside. Of the

Power supply connection and / or the communication interface can serve to form a plug connection.

According to a further advantageous embodiment, the base body has at least one receptacle for a sliding bearing or a rolling bearing. About the sliding bearing or rolling bearing, a rotor shaft of an electric machine can be rotatably mounted on the bearing plate. The receptacle can be designed as a bushing for a plain bearing or as a seat for a rolling bearing, in particular ball bearings. The receptacle can be formed from plastic or metal, wherein in the latter case, a corresponding metal body for connection to the rest of the base body during an injection molding process can be partially encapsulated. The slide bearing can be injected directly into the main body or its recording during an injection molding or a

corresponding insert to be encapsulated.

According to a further advantageous embodiment, the base body has at least one molding element for fixing and / or electrical contacting of at least one winding end of a winding of the rotor or the stator of the electrical machine to the electrical conductor tracks of the

Body on. As a result, a winding end is not fixed solely on its electrical contact with the bearing plate, which is associated with a more robust design of a provided with the bearing plate electrical machine. The base body can also offer a possibility for concealed electrical contacting between the drive electronics and winding ends by a suitable arrangement of further form elements on the base body. According to a further advantageous embodiment, at least one metallic component is arranged on the base body. With the metallic component are an improvement in thermal properties, such as the cooling of the drive electronics, and / or an improvement

electromagnetic properties, such as influencing the

Drive electronics by the electromagnetic active part (stator windings, rotor windings) of an electrical machine, connected.

According to a further advantageous embodiment, the bearing plate at least one can be arranged between the base body and a housing of the electric machine sealing element, via which a drive electronics-containing space within the body and the housing relative to the environment of the electrical machine is sealable. As a result, the drive electronics can be effectively protected against environmental influences, in particular dust and moisture. The sealing element may be formed as molded onto the base sealing lip. Two or more sealing elements can also be arranged on the main body.

A further advantageous embodiment provides that at least one mold element for mechanical connection of the base body is arranged with a component to be connected to the electrical machine on the base body. About the form element, for example, a downstream of the electric machine gearbox can be connected to the electric machine. Mounting holes or the like may also be formed on the base body in order to be able to mechanically connect the endshield or an electric machine equipped therewith with another component.

According to a further advantageous embodiment, the drive electronics is arranged and formed on the base body such that at a

Arrangement of the bearing plate on a housing of the electric machine, an electrical contact between the drive electronics and a winding of the stator or the rotor of the electric machine is automatically produced. For this purpose, for example, an insulation displacement technology can be used.

Alternatively, the electrical contacting of the windings of the

Electromagnetic active part of an electric machine with the Drive electronics are made before mounting the bearing plate to the housing.

The invention further relates to an electrical machine, in particular a brushless DC motor, with a housing and two axial ends of the housing occlusive end shields, characterized

characterized in that at least one end shield according to one of

previously mentioned embodiments or any combination thereof is formed. With this electric machine, the advantages mentioned above with respect to the end plate are connected accordingly.

The electric machine may have a magnet rotor equipped with permanent magnets, an electromagnetic active part, a stator housing carrying the electromagnetic active part, and end shields closing two axial ends of the stator housing. The electric machine can be designed, for example, as a brushless DC motor or as a converter-fed three-phase machine. The electric machine can

for example, to drive a windshield wiper system, an electric seat adjustment, a sunroof or as a fan / fan motor, as an electric oil / water pump, used as an ABS actuator or the like. Furthermore, the electric machine for forming an electric tool, such as a Akkusch raubers, Akkubohrers, battery chute or the like, can be used. Also, the electric machine can be used in the field of logistics or production, for example, a conveyor drive or a drive for a

Form handling device.

According to an advantageous embodiment, the housing and at least one bearing plate are designed such that the bearing plate over a

Locking mechanism can be fixed to the housing. The latching mechanism may be formed by a snap mechanism, a clip mechanism or the like, for example. By the locking mechanism that is

End shield without additional joining aids, such as

Screws or the like, can be fixed to the housing of the electrical machine. In the following, the invention will be explained by way of example with reference to the appended figures with reference to preferred exemplary embodiments, wherein the features illustrated below may represent an aspect of the invention both individually and in various combinations with one another. Show it

FIG. 1 is a schematic exploded view of a conventional electrical machine;

FIG. 2 shows a schematic exploded view of an exemplary embodiment of an electrical machine according to the invention,

Figure 3: a schematic exploded view of another

Embodiment of an electrical machine according to the invention.

Figure 1 shows a schematic exploded view of a conventional electric machine 1 in the form of a brushless DC motor. The electric machine 1 comprises a housing 2, on which a stator winding 20 is arranged, which is installed in a laminated core 3 made of soft iron. Furthermore, the electric machine 1 comprises a rotor 4 with a rotor shaft 5. The rotor shaft 5 is mounted on the output side via a bearing plate 6 and not on the output side via a bearing plate 7 on the housing 2 or storable. At the end shields 6 and 7, a receptacle 8 for receiving a sliding bearing or ball bearing 9 is arranged in each case. In addition, the electrical

Machine at least 1 a separate board 10 with a logic and

Power electronics on. Furthermore, the electric machine 1 comprises a

Protective hood 11, which can be plugged over the end of the housing 2 shown on the left, in particular to protect the board 11 from environmental influences.

FIG. 2 shows a schematic exploded view of a

Embodiment of an electric machine 12 according to the invention in the form of a brushless DC motor. Components of the electric machine 12, which are realized in accordance with the electrical machine 1 according to Figure 1, are provided with the same reference numerals. The electric machine 12 comprises a housing 2 and two axial ends of the housing 2 closing end shields 6 and 13. The end plate 13 is formed according to the invention and comprises a base body 14 and arranged on the base body 14 drive electronics 15 for driving the electric machine 12, wherein the drive electronics 15 electronic components 16 can be seen. The main body 14 is formed as an injection-molded circuit carrier made of plastic, are arranged on the not shown electrical conductor tracks of the drive electronics 15.

The drive electronics 15 comprises at least one electrical logic unit, at least one electrical power electronics, at least one electrical contacting unit and / or at least one electrical sensor unit, these units being not shown in greater detail. Furthermore, the

Drive electronics 15 at least one power supply connection and at least one communication interface, which is also not shown in detail. The drive electronics 15 is arranged and formed on the base body 14 in such a way that, in the case of an arrangement of the end shield 13 on the housing 2 of the electric machine 12, an electrical contact between the drive electronics 15 and a stator winding 20 of the electric machine 12 can be produced automatically.

The main body 13 has a receptacle 17 for the ball bearing 9 shown on the left. In addition, the base body 13 comprises at least one non-illustrated molding element for fixing at least one winding end of a

Stator winding 20 of the electric machine 12 on the base body 14. Furthermore, at least one non-illustrated metallic component is arranged on the base body 14. At least one sealing element (not shown) is arranged on the base body 14 in order to seal the base body 14 relative to the housing 2 of the electric machine 12. Furthermore, at the

Base 14 arranged at least one non-shown mold element for the mechanical connection of the base body 14 with a to be connected to the electric machine 12, not shown component. The housing 2 and the bearing plate 13 are formed such that the bearing plate 13 is fixable to the housing 2 via a latching mechanism, not shown. Figure 3 shows a schematic exploded view of another embodiment of an electric machine 12 according to the invention. In contrast to the embodiment shown in Figure 2, a receptacle 18 is arranged on the bearing plate 13, on which a sliding bearing 19 is arranged.

Claims

claims

1. bearing plate (13) for an electrical machine (12), in particular a

brushless DC motor, characterized by at least one main body (14) and at least one on the main body (14)

arranged drive electronics (15) for driving the electrical

Machine (12).

Bearing shield (13) according to claim 1, characterized in that the base body (14) is designed as an injection-molded circuit carrier.

3. bearing plate (13) according to claim 1 or 2, characterized in that the drive electronics (15) at least one electrical logic unit, at least one electrical power electronics, at least one electrical

Contacting unit and / or at least one electrical sensor unit.

4. bearing plate (13) according to one of claims 1 to 3, characterized in that the drive electronics (15) at least one

Power supply connection and at least one

Communication interface has.

5. bearing plate (13) according to one of claims 1 to 4, characterized in that the base body (14) has at least one receptacle (17, 18) for a sliding bearing (19) or a rolling bearing (9).

6. bearing plate (13) according to one of claims 1 to 5, characterized in that the base body (14) at least one molding element for fixing and / or electrical contacting of at least one winding end of a winding of a stator or rotor (4) of the electrical machine ( 12) on the electrical conductor tracks of the base body (14).

7. bearing plate (13) according to one of claims 1 to 6, characterized in that on the base body (14) at least one metallic component is arranged.

8. bearing plate (13) according to one of claims 1 to 7, characterized by at least one between the base body (14) and a housing (2) of the electrical machine (12) can be arranged sealing element, via which the drive electronics (15) containing space within the base body (14) and the housing (2) relative to the environment of the electrical machine (12) is sealable.

9. bearing plate (13) according to one of claims 1 to 8, characterized in that on the base body (14) at least one molding element for

mechanical connection of the base body (14) is arranged with a component to be connected to the electrical machine (12).

10. end shield (13) according to one of claims 1 to 9, characterized in that the drive electronics (15) is arranged and formed on the base body (14) such that in an arrangement of the end plate (13) on a housing (2) the electric machine (12) an electrical

Contact between the drive electronics (15) and a winding (20) of the stator or the rotor (4) of the electric machine (12) is automatically produced.

11. Electrical machine (12), in particular brushless DC motor, with a housing (2) and two axial ends of the housing (2) closing end shields (6, 7, 13), characterized in that at least one end plate (13) according to one of Claims 1 to 10 is formed.

12. Electrical machine (12) according to claim 11, characterized in that the housing (2) and at least one bearing plate (13) are formed such that the bearing plate (13) via a latching mechanism on the housing (2) is fixable.