WO2012110134A1

WO2012110134A1 - Electric machine and system for the forced switching off of the energy supply of said type of electric machine

Info

Publication number: WO2012110134A1
Application number: PCT/EP2011/072083
Authority: WO
Inventors: Raphael Fischer; Tobias Vogler
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2011-02-16
Filing date: 2011-12-07
Publication date: 2012-08-23
Also published as: DE112011104897A5; DE102011080005A1; WO2012110138A1

Abstract

The invention relates to an electric machine (12), in particular an electric wheel hub motor (10), comprising a rotor (14), a stator (16) and a housing (18) which at least partially surrounds the rotor (14) and the stator (16). Said rotor (14) and/or stator (16) comprise pole teeth (32) which are arranged on the periphery and slits (34) which are between said teeth. According to the invention, the electric machine (12) also comprises at least one sensor (56) with a sensor element (58) and signal lines (60) for a system for the forced switching off. The signal lines (60) of the sensor (56) are guided into one of the slits (34). The invention also relates to a corresponding system for the forced switching off.

Description

Name of the invention

ELECTRICAL MACHINE AND SYSTEM TO FORCED ENERGY SUPPLY OF SUCH ELECTRICAL MACHINE

5 description

Field of the invention

The invention relates to an electric machine, in particular a 10-wheeled electric motor, with a rotor, a stator and a housing at least partially housing the rotor and the stator, wherein the rotor and / or the stator has circumferentially arranged pole teeth and intermediate slots.

Such an electric machine is known, for example, as an electric wheel motor from the patent EP 0751 026 B1. This electric motor has a rotor and a rotor circumferentially surrounding the stator with a yoke core and a plurality of pole teeth having magnetic pole core. Between each two adjacent pole teeth results in a slot. Rotor and stator

20 are at least partially housed by a housing of the electric machine.

Some electrical machines, such as electric machines for electric or hybrid powertrains of motor vehicles, are loaded with voltages.

25, which are mostly in the range of more than 100 volts. Such voltages are dangerous to the human body, so these electrical machines may only be maintained and repaired by suitably trained personnel. If there is a fault in the electrical machine or it is opened, it must be ensured that of this

30 electrical machine no danger.

In electrical systems and devices, this is usually ensured by a so-called interlock system (a system for forced shutdown), in which at least one sensor checks whether the system or the device is in a suitable operating condition for the operation and the system or the device disconnects from its power supply, if this is not the case.

In general, the electric machine can be designed as a generator and / or electric motor. A particular embodiment of the electric motor is the electric wheel hub motor. A wheel hub motor is an electric motor that is directly installed in a wheel of a vehicle and at the same time carries the wheel hub, so that a part of the engine rotates with the wheel. When designed as an internal rotor electric wheel hub motor often results in a very tight radial dimensioned space within the housing.

The invention has for its object to provide an electrical machine, which ensures reliable transmission of a forced shutdown causing signal even in a small space within its housing.

The object is achieved by the features of claim 1. Advantageous embodiments of the invention are specified in the dependent claims.

In the electrical machine according to the invention it is provided that the electric machine further comprises at least one sensor with sensor element and signal lines for a system for forced shutdown (interlock system), wherein the signal lines of the sensor are guided in one of the slots. If several sensors are provided, the corresponding signal lines of the individual sensors are preferably guided in separate slots. The slots accommodate the windings of the rotor or stator, but are generally not completely filled with them. Therefore, there is usually enough space to lay the signal lines. The electric machine can have one or more sensors. The sensor or the sensors monitor whether the electric machine is in a suitable state for the operation thereof. If it detects a state deviating from the proper operating state, then a control device for controlling the power supply of the electrical machine of the system for forced shutdown disconnects the electric machine from its power supply. Of course, the sensor signal can alternatively or additionally be used for other measures, such as a signaling of the state.

The electric machine is an electric motor and / or a generator. A particular embodiment of the electric motor is a wheel hub motor; the corresponding embodiment of the generator is a hub dynamo.

The electric machine is in particular an electric machine for driving a motor vehicle. Such electrical machines are operated with voltages of more than 100 volts. The corresponding drive types are an electric drive or a hybrid drive, in which the electric machine is usually used together with an internal combustion engine as drive machines. In particular, it is provided that the sensor element or the sensor elements is arranged in the interior of the housing / are.

According to an advantageous embodiment of the invention it is provided that the housing is formed as an apparent housing. In the case of an apparent housing, at least one sensor monitors whether the housing of the electrical machine is in the "housing open" or "housing closed" state. When the housing is closed, the electrical machine is in a proper operating state, with the housing open in an improper operating state.

It is preferably provided that the opening of the apparent housing by removal and / or by pivoting and / or moving at least least one housing part takes place. The housing part is for example a cover, a lid, a flap, etc.

According to a further advantageous embodiment of the invention, it is provided that the sensor element is designed as a switch. This switch is preferably a push button switch. It is advantageously provided that the switch is designed as a switch closing in its depressed state.

In particular, it is provided that the switch is depressed by the housing part when the housing is closed. For example, as long as the switch is depressed, a forced shutdown circuit is closed, signaling the proper operating condition. If the housing part is displaced, the switch is no longer depressed, the circuit is opened and the system for forced shutdown disconnects the electrical machine from its power supply.

According to an advantageous embodiment of the invention it is provided that an end facing away from the sensor element, the signal lines is led out of the housing. This end can be used for electrical connection to the remaining components of the system for forced shutdown.

According to a further advantageous embodiment of the invention, it is provided that the signal lines of the sensor are twisted together. Twisted signal lines are less prone to the electromagnetic interference caused by the electromagnetically interacting parts of the electric machine and introduce the corresponding interference signals in the signal lines.

In particular, it is provided that the signal lines have a common shielding. Such a shield surrounds the signal lines of the sensor and shields them against external influences such as the aforementioned electromagnetic interference. According to an advantageous embodiment of the invention it is provided that the signal lines are surrounded at its end facing away from the sensor element with a ferrite core or connected to a frequency filter. The frequency filter is in particular an active or passive low-pass filter. All these measures are used to filter out faults.

In particular, it is provided that the sensor further comprises an antenna extending parallel to the signal lines, the signal of which is fed to the frequency filter designed as an active filter. Such an antenna is particularly susceptible to the aforementioned external influences, including the electromagnetic interference. By comparing the signal from the antenna with the signal of the signal lines, the interference signals caused by the external influences can be actively separated from the actual sensor signal in a particularly effective manner.

Furthermore, it is advantageously provided that the sensor element is detachably fastened to at least one pole tooth or is releasably secured. For this purpose, the sensor element is preferably clamped / clamped to the pole tooth. The invention further relates to a system for forced shutdown, with an electrical machine and a control device for controlling the power supply of the electrical machine in response to a sensor signal. According to the invention, it is provided that the electric machine is designed as an electrical machine mentioned above, wherein the signal lines of the sensor for the transmission of the sensor signal are signal-technologically connected to the control device. The control device is, for example, a control unit of the electric machine, in the case of an electric motor that is an engine control unit. The electric machine is preferably a wheel hub motor. The invention will be explained in more detail with reference to the accompanying drawings with reference to preferred embodiments. a sectional view of the upper part of an electric wheel hub motor designed as an electric machine with stator, rotor and housing according to a first embodiment of the invention, a detailed representation of the pole teeth with intermediate slots on the inside of the stator shown in Fig. 1, a sectional view of the in Fig. 2 of the stator, a detailed view corresponding to FIG. 2, wherein anchoring structures for fastening the sensor element of the sensor to the stator are shown, FIG.

Fig. 5 is a sectional view corresponding to FIG. 2, wherein the attached

Sensor element is shown

Fig. 6 to 10 detailed representations of the wiring of the sensor on the stator with various measures for the suppression of interference signals.

1 shows a sectional view of one half of an electric wheel hub motor 10 designed as electrical machine 12. The electric machine 12 has a rotor 14 (also called rotor), a stator 16 (also called stator) and a rotor 14 and the stator 16 housing housing 18 on. Rotor 14 and stator 16 are arranged coaxially with respect to a motor axis 20. The rotor 14 is rotatably mounted on a shaft 22 running along the motor axis 20. For this purpose, a plurality of bearings 24 are arranged between the rotor 14 and the shaft 22. These are formed in the illustrated electric machine 12 as a ball bearing. The rotor 14 has at its Outer periphery 26 magnets 28, of which in Fig. 1, only one is visible. The magnets 28 are designed as permanent magnets.

The stator 16 surrounds the rotor 14 circumferentially and, on its inner periphery 30 facing the magnets 28, has a multiplicity of pole teeth 32 with slots 34 (ie, spaces between the teeth 32) between them. Described differently around these slots 34 can be in the form of grooves on the inner circumference of the stator 16, a plurality of pole teeth 32 arise. Between the highest elevations of these pole teeth 32 and the outer surface of the magnets 28, the so-called air gap of the electric machine 12 is formed.

The stator 16 further has a winding arrangement 36, the individual windings 38 are inserted into the slots 34. At their respective axial end areas 40, 42, corresponding winding heads 44, 46 are formed. Rotor 14 and stator 16 are surrounded in their outer area by an outer housing part 48 of housing 18, while in their inner area at least on one side by a housing inner part 50 having the shaft 22 be covered. On the side opposite this side, another housing part 52 is releasably secured to the housing outer part 48, wherein this housing part 52 at least partially covers the rotor 14 and the stator 16 in a housing-like manner. The housing 18 is thus designed as an apparent housing 54.

The electric machine 12 also has a sensor 56 with a sensor element 58 and associated signal lines 60 for a system for forced shutdown, an interlock system, the electric machine 12, this system is not shown in its entirety.

In the illustrated embodiment, the sensor element 58 of the sensor 56 is designed as a switch 62, more precisely as a pushbutton switch. This key switch serves as a break contact of the interlock system or an interlock circuit. The sensor element 58 designed as a switch 62 is fastened to the one end region 40 such that the switch 62 is pressed down by the housing part 52 when the housing 18, 54 is closed. If the housing part 52 is removed or removed, the switch 62 opens and the corresponding interlock circuit is opened.

The signal lines 60 of the sensor 56 are guided by the sensor element 58 or the switch 62 through or along the one winding head 44 at one end portion 40 radially outward and then axially through one of the slots 34 to the other end portion 42. There, an end 64 of the signal lines 60 is guided through a corresponding opening 66 in the housing 18, 54 to the outside. This guidance of the signal lines 60 contributes to the particular installation space situation in compact electrical machines 12, such as wheel hub motors 10. But it is equally applicable to all tasks in which similar geometric situations occur.

This results in the following situation: Since the representable torque increases in electrical machines 12 square with the diameter of the air gap, the maximization of this diameter counts in the design of the electric machine 12 to the most important tasks. At the same time exist on the part of the given space limitations, which are given for example in radintegrierten drives through the rim. When looking at an inner rotor it is noticeable that the outer housing part 48, which, inter alia, undertakes the encapsulation of the high-voltage circuit for supplying voltage to the electric machine 12, can be monitored by a sensor element 58, but the signal lines 60 are not outside the wheel hub motor 10 (here only a minimum gap to the rim) can still be performed by the rotating inner part (ie the rotor 14). The signal lines are therefore guided through the stationary part of the electric machine 12. This standing part is formed by the lamination of the stator 16, the winding assembly 36, a cooling jacket, not shown here, and the housing 18, 54. The space situation is in the optimized case so close that at first viewing no way for the signal lines 60 remains.

However, since the slots or grooves are not filled to 100% by the windings 38 of the winding assembly 36, usually remains in previous electrical machines 12 always a small passage per slot 34, which can be used. The signal lines 60 are thus placed together with the windings 38 through the slots / grooves 34 of the electric machine 12. Figs. 2 and 3 show this situation in detail. They each show a portion of the stator 16 with three pole teeth 32 and intermediate slots 34. The pole teeth 32 are wound with turns 38 of the winding assembly 36 of the stator 16. In one of the slots 34 are the signal lines 60 (one outgoing and one return line) of the sensor 56 a.

The illustration in FIG. 4 essentially corresponds to that of FIG. 2 and shows additional anchoring arms 68 of the sensor element 58, by means of which the sensor element 58 can be fastened to the stator 16. The type of attachment is particularly clear in Fig. 5.

FIG. 5 shows a sectional view corresponding to FIG. 3, wherein the detachable attachment of the sensor element 58 to the stator 16 is shown. For this purpose, the sensor element 58 has the two anchoring arms 68, by means of which it is fastened to a pole tooth 32 and the corresponding turns 38 wound around this pole tooth 32 in the area of the one winding head 44 (for example by casting in / on this winding head 44) ,

Since the winding arrangement 36 of the electric machine 12 is traversed by high pulsed alternating currents, the influencing of the signals is to be considered on the signal lines 60 by the resulting magnetic fields.

The sensor signal on the signal lines 60 usually consists of a predetermined current of e.g. 10 mA. A voltage drop in the interlock system or interlock circuit is evaluated for the forced shutdown. If the voltage drop too high, the shutdown of the power supply of the electric machine 12 is caused by the system for forced shutdown.

The induced in the sensor 56, in particular its signal lines 60, disturbances are to be kept at a level that excludes a false response of the system to shutdown (the interlock monitoring). The cheapest and most effective measure is a suitable routing. Figures 6 to 10 show detailed representations of the wiring of the sensor 56 on the stator 16 with various measures for the suppression of interference signals. Fig. 6 shows the return line of the signal lines 60, which are laid close to each other, here even twisted together. Due to the close spatial guidance of the forward and return lines, induced disturbances at least partially cancel each other out.

As a further measure, FIG. 7 shows a shielding 70 of the signal lines 60. A shield 70 of the signal lines 60 further attenuates the influence of interference.

Furthermore, damping in the signal lines 60 can be achieved by the use of ferrite cores 72 (FIG. 8). The leads 60 are for this purpose led close to the terminals or the end 64 through the ferrite core 72.

The most expensive measure is the filtering, in particular active filtering. Fig. 9 shows a corresponding arrangement in which the signal lines 60 at its the sensor element 58 facing away from the end 64 are connected to a frequency filter 74. The interfering pulses in the winding arrangement can be detected by an antenna 76, which is guided parallel to the signal lines 60, and fed to a frequency filter 74, which is designed as an active filter.

As already mentioned, another aspect of the present invention relates to the sensor element 58 itself. Since, as shown in the exemplary embodiment, it can be arranged such that it is in the way when the rotor 14 is dismantled, it must itself also be removable. At the same time its attachment (so for example, the two anchoring arms 68) to be designed so that it disappears in the bobbin of the machine 12.

For this purpose, the mechanical orientation of the sensor element 58 is combined with the electrical contact.

The easiest way is to connect by screws. The contact is first positioned against rotation by means of a suitable contour and then secured with one or more screws.

An elegant way to position the contact and secure at the same time forms a positive connection on the principle of dovetail guide by means of two anchoring arms 68. The key here is the insertion direction: The sensor element 58 is pushed with the housing part 52 in the guide and stops there in 5 degrees of freedom by positive locking and in the last degree of freedom by friction. The fuse in this direction is done by placing the removable housing part 52nd LIST OF REFERENCE NUMBERS

Electric hub motor

Electric machine

rotor

stator

casing

motor axis

wave

camp

outer periphery

magnet

inner circumference

pole tooth

slot

winding arrangement

convolution

end

winding

Housing outer part

Housing inner part

housing part

Apparent housing

sensor

sensor element

signal line

switch

The End

breakthrough

anchoring arms

shielding ferrite

frequency filter

antenna

Claims

claims

1 . Electric machine (12), in particular electric wheel hub motor (10), with a rotor (14), a stator (16) and a housing (18) at least partially housing the rotor (14) and the stator (16) the rotor (14) and / or the stator (16) has circumferentially arranged pole teeth (32) and intermediate slots (34),

characterized by at least one sensor (56) with sensor element (58) and signal lines (60) for a system for forced shutdown, wherein the signal lines (60) of the sensor (56) are guided in one of the slots (34).

2. Electrical machine according to claim 1, characterized in that the housing (18) as an apparent housing (54) is formed.

3. Electrical machine according to claim 2, characterized in that the opening of the apparent housing (54) by removing and / or by pivoting and / or displacement of at least one housing part (52).

4. Electrical machine according to one of the preceding claims, characterized in that the sensor element (58) as a switch (62), in particular as a key switch, is formed.

5. Electrical machine according to claim 4, characterized in that the switch (62) with the housing closed (18, 54) through the housing part

(52) is depressed.

6. Electrical machine according to one of the preceding claims, characterized in that a sensor element (58) facing away from the end (66), the signal lines (60) from the housing (18, 54) is led out.

7. Electrical machine according to one of the preceding claims, characterized in that the signal lines (60) are twisted together.

8. Electrical machine according to one of the preceding claims, characterized in that the signal lines (60) have a common shield (70).

9. Electrical machine according to one of the preceding claims, character- ized in that the signal lines (60) at its the sensor element (58) facing away from the end (64) with a ferrite core (72) are surrounded or connected to a frequency filter (74).

10. A system for forced shutdown, comprising an electric machine (12) and a control device for controlling the power supply of the electrical machine (12) in response to a sensor signal, characterized in that the electrical machine (12) is designed according to one of the preceding claims, wherein the signal lines (60) of the sensor (56) are signal-technically connected to the control device for transmitting the sensor signal.