DE102014218707A1 - Common resolver for two electric motors of a differential drive in the vehicle - Google Patents

Abstract

The invention relates to a sensor (29) for outputting a first sensor signal (40) as a function of a first angular position (30) of a first shaft (9) of a first electric motor (4) and of a second sensor signal (43) in dependence on a second angular position (30 ) of a second shaft (9) of a second electric motor (4), comprising: - a first sensor (39) for detecting a first encoder field (38) excited stationary with the first shaft (9) and for outputting the first sensor signal (40) Dependence of the detected first encoder field (38), - a second sensor (42) for detecting a second encoder field (41) excited stationary with the second shaft (9) and for outputting the second sensor signal (43) as a function of the detected second encoder field (41 ), and - a circuit carrier (33), on which the first sensor (39) and the second sensor (42) are arranged in different sensing directions together.

Description

The invention relates to a sensor for outputting a first and second sensor signal in response to a first and second angular position of a shaft, a drive with the sensor and a vehicle with the drive.

If brushless electric motors are used in a vehicle, the rotational angle of the rotor of the electric motor must be known for the external commutation in order to build up the magnetic drive field in the electric motor accordingly. For this purpose, sensors in the form of angle encoders, also called resolvers, are used as a rule, such as from the EP 255 54 17 A1 known.

It is an object of the invention to improve these sensors.

The object is solved by the features of the independent claims. Preferred developments are the subject of the dependent claims.

According to one aspect of the invention, a sensor for outputting a first sensor signal as a function of a first angular position of a first shaft of a first electric motor and a second sensor signal in dependence on a second angular position of a second shaft of a second electric motor, a first sensor for detecting a stationary with the first Wave excited first encoder field and the output of the first sensor signal in response to the detected first encoder field, a second sensor for detecting a second encoder field excited stationary with the second wave and output of the second sensor signal in response to the detected second encoder field, and a circuit carrier on the the first sensor and the second sensor are arranged in different Sensierrichtungen together arranged.

The specified sensor is based on the consideration that in a vehicle with a plurality of brushless electric motors, each individual electric motor requires its own angle sensor also referred to below, in order to be able to operate accordingly. Such vehicles are known as vehicles with differential drive. However, the angle encoders have a high space requirement, which is not sufficiently available especially in vehicles.

Here, the specified sensor sets with the knowledge that the same axis of rotation leads through the wheels located on the vehicle at the rear axle and through the wheels located on the vehicle at the front axle. This knowledge is made use of in the specified sensor by the sensors for the two electric motors on the rear axle or on the front axle are interconnected on a common circuit board. The thus proposed sensor can then be arranged axially between the two electric motors and axially detect the angular position of the corresponding waves of the electric motors on both sides.

In this way, a circuit substrate can be saved, which not only leads to the said reduction of space, also material and manufacturing costs are saved and the installation of the specified sensor in a vehicle is simplified.

In a further development of the specified sensor, the two sensors are arranged in opposite Sensierrichtungen arranged on the circuit substrate. These Sensierrichtungen can then run exactly on the aforementioned axis of rotation of the two shafts, the two sensors can be brought as close as possible to the corresponding waves.

In another development, the specified sensor comprises a shielding element between the two sensors, which shields the first encoder field and the second encoder field accordingly from the second sensor and the first sensor. In this way, it is avoided that the two sensors are influenced by the other encoder field and thus provide incorrect measurement results, whereby the reliability of the total system using the sensor can be increased.

Alternatively or additionally, however, the sensor signals from the sensors can also be separated from one another via signal processing.

In yet another development of the specified sensor, at least one of the two sensors is arranged on a heel element, via which the two sensors are spaced from each other. In this way, the sensors can not only be brought closer to the waves of the corresponding electric motors, the distance between the sensors is also increased, whereby the aforementioned influences of the sensor by the other encoder field is also further reduced.

In a further development of the specified sensor, the two sensors are magnetoresistive sensors. Magnetoresistive sensors are inexpensive and have a high reliability, especially for electric motors used in vehicle construction.

In a further development, the specified sensor comprises a first transmitter element for outputting the first transmitter field and a second transmitter element for outputting the second transmitter field, wherein the circuit carrier is arranged with the two sensors between the two transmitter elements.

In order to reinforce the encoder field in the direction of the sensor, the specified sensor in a particular embodiment may comprise a first return element and a second return element corresponding short the first and second encoder field on the first and second donor element on a side opposite the circuit carrier.

In a preferred development of the specified sensor, the first and second transmitter elements are magnets that are magnetized on a side facing the sensors. In this way, the number of poles of the donor elements is increased, whereby less encoder field is to be measured with the same volume of magnet, as in otherwise magnetized donor elements, such as diamagnetically magnetized magnet.

According to a further aspect of the invention, a drive for a vehicle having a first wheel and a second wheel, which axially movably support a chassis on a ground comprises a first electric motor having a first stator, a first rotor rotatably mounted in the first stator, via a first magnetic drive field is drivable in an air gap between the first stator and the first rotor, a second electric motor with a second stator, a second rotor rotatably mounted in the second stator, the second rotor via a second magnetic drive field in an air gap between the second stator and the second rotor is drivable, a first control means for generating the first magnetic drive field based on a rotational position of a rotatably connected to the first rotor and the first wheel driving shaft, a second control means for generating the second magnetic drive field based on a Drehstellun g of a rotatably connected to the second rotor and the second wheel driving shaft and one of the specified sensors for detecting the rotational positions of the first and second shaft.

According to a further aspect of the invention, a vehicle comprises a chassis that is movably supported on a ground at least on a first wheel and a second wheel and one of the specified drives for driving the two wheels.

The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the embodiments, which will be described in connection with the drawings, wherein:

1 a schematic view of a vehicle with a vehicle dynamics control,

2 a schematic representation of an electric motor for the vehicle of 1 .

3 a schematic representation of a drive for the vehicle of 1 with two electric motors the 2 .

4 a schematic representation of a 3 alternative drive,

5 a schematic representation of an angle sensor for driving the 4 .

6 a schematic representation of an alternative angle sensor for driving the 4 .

7 a schematic representation of a still alternative angle sensor for driving the 4 .

8th a schematic representation of a further alternative angle sensor for driving the 4 , and

9 a schematic representation of a still further angle encoder for driving the 4 demonstrate.

In the figures, the same technical elements are provided with the same reference numerals and described only once.

It will open 1 Reference is made to a schematic view of a vehicle 1 with a known vehicle dynamics control shows. Details of driving dynamics regulations in general, for example, the DE 10 2011 080 789 A1 be removed.

The vehicle 1 includes a chassis 2 and four wheels 3 , Every bike 3 can be via an individual electric motor 4 accelerated and propelled to the vehicle 2 to move on a road, not shown. The drive of the vehicle 1 is doing so via a so-called engine control 5 controlled. A driver of the vehicle 1 gives this over an accelerator pedal 6 a so-called driver's request 7 before, which is usually dependent on a desired driving force for the vehicle 1 is. The engine control 5 then controls based on this driver wash 7 every individual electric motor 4 with an individual drive signal 8th in order to implement the driver's request 7 with the respective electric motor 4 to generate a torque that then passes over a shaft 9 to the respective bike 3 is applied to the vehicle 1 to move with the desired propulsive force.

It can happen in a manner known to those skilled in the way that the wheels 3 of the vehicle 1 lose their grip and get the vehicle 1 even moved away from a given example by a steering wheel not shown steering trajectory by understeer or oversteer. This is avoided by known control circuits such as ABS (antilock braking system) and ESP (electronic stability program).

In the present embodiment, the vehicle 2 for speed sensors 10 at the wheels 6 on that one speed 11 the wheels 3 to capture. Further, the vehicle points 1 an inertial sensor 12 on, the driving dynamics data 13 of the vehicle 1 from which, for example, a pitch rate, a roll rate, a yaw rate, a lateral acceleration, a longitudinal acceleration and / or a vertical acceleration can be output in a manner known to a person skilled in the art.

Based on the recorded speeds 11 and vehicle dynamics data 13 can be a regulator 14 in a manner known to those skilled determine whether the vehicle 2 slips on the road or even deviates from the above-mentioned predetermined trajectory and correspond with a known controller output signal 15 to react to that. The regulator output signal 20 can then from the engine control 5 in the control of the electric motors 4 via the control signals 8th be taken into account. In this case we speak of a vehicle dynamics control based on "torque vectoring".

The regulator 14 and the engine control 5 are shown as separate units for clarity only. As a rule, they are designed as a common signal processing device.

The following is based on the 2 one of the electric motors 4 be explained in more detail.

The electric motor 4 has a fixed to the chassis 2 mountable stator 16 and a rotationally fixed with the shaft 9 connectable rotor 17 on, in 2 the wave 9 already on the rotor 17 is indicated connected.

At the stator 16 are excitation coils 18 arranged to the electrical excitation currents 19 can be created. The excitation coils 18 build with the applied excitation currents 19 single magnetic fields, which are to be put together to form a stator field referred to magnetic drive field to the rotor 17 drive.

This is about the rotor 17 also constructed a magnetic field referred to below rotor field. This rotor field, for example, by a permanent magnet with a north pole 20 and a south pole 21 are energized, the permanent magnet for mechanical reasons still from a cuff 22 can be enclosed. The excitation current 19 will now be in a manner to be described in such a way to the exciter windings 18 created that through the excitation windings 18 excited Statorfeld turns. In this way, the stator field pushes the poles 20 . 21 of the rotor field in front of him and thus rotates the shaft 9 ,

The electric motor 4 can for its operation, for example, with a DC voltage 23 be supplied to the electric motor 4 a direct current 24 impresses. For generating the excitation currents 19 from the direct current 24 is a bridge circuit 25 present, via a control device 26 is controlled.

The bridge circuit 25 indicates for each exciting current to be generated 19 a separate half bridge from a series connection of two switches 27 on, with the half bridges all parallel to the input voltage 23 are switched. The switches 27 be from the controller 26 with control signals 28 driven.

The control signals 28 must be generated in such a way that the of the excitation coils 18 to be built magnetic individual fields as a function of the angular position of the rotor 17 and thus the wave 9 change their polarity. In this way it is achieved that the resulting from the magnetic fields magnetic stator field rotates and so the rotor 17 over the poles 20 . 21 of the rotor field drives.

This requires the controller 26 for generating the control signals 28 the angular position of the rotor 17 opposite the stator 16 know what in the context of the present embodiment with a stationary to the stator 16 arranged angle encoder 29 to be detected, which is the angular position 30 of the rotor 17 opposite the stator 16 recorded and this to the controller 26 outputs so that these are the control signals 28 can generate.

This angle encoder 29 must, as in 3 based on the rear axle drive 31 of the vehicle 2 of the 1 shown on every electric motor 4 be individually present, but this is associated with a correspondingly required space.

In order to reduce this space required is proposed in the present embodiment, the angle encoder 29 at the rear axle drive 31 of the vehicle 1 and / or on the front axle drive of the vehicle 1 for both electric motors 4 to execute together. This proposal is based on the consideration that the wheels 3 at the rear axle drive 31 of the vehicle 1 and thus the waves 9 around the same axis of rotation 32 rotate. The same applies to the front axle drive of the vehicle 1 ,

This for the two electric motors 1 the rear axle drive 31 jointly constructed angle encoders 29 will be described below on the basis of 5 be explained in more detail.

The angle encoder 29 includes a circuit carrier 33 with a top 34 and one of the top 34 opposite bottom 35 , The top 34 is a first donor element 36 in the form of a permanent magnet with a north pole 20 and a south pole 21 facing, while the bottom of a second donor element 37 also faces in the form of a permanent magnet with a north pole and a south pole.

The first donor element 36 is non-rotatable on the shaft 9 one of the two electric motors 4 attached and excited a first donor field 38 in the form of a magnetic field. This first donor field 38 Penetrates a first sensor 39 , which should be expediently designed as a magnetically sensitive sensor, for example in the form of a magnetoresistive sensor. Because the first donor element 36 stationary on the shaft 9 one of the electric motors 4 is attached, the first encoder field rotates 38 together with this wave 9 , whereby the angular position of the first encoder field 38 opposite the stationary to the chassis 2 the vehicle held first sensor 39 changed. The first sensor 39 is designed such that it has a first encoder signal 40 depending on the angular position of the first encoder field 38 opposite the first sensor 39 outputs. This first encoder signal 40 can already be considered the desired angular position 30 the wave 9 of the corresponding electric motor 4 to the controller 26 be transmitted. Alternatively, the first encoder signal 40 but also in a signal conditioning circuit 40 before sending to the controller 26 in the desired angular position 30 be transformed. In any case, the first encoder signal 40 from the desired angular position 30 dependent.

The second donor element 37 is non-rotatable on the shaft 9 the other of the two electric motors 4 attached and energized a second encoder field 41 in the form of a magnetic field. This second donor field 41 Penetrates a second sensor 42 , which should be expediently also designed as a magnetically sensitive sensor, for example in the form of a magnetoresistive sensor. Because the second donor element 37 stationary on the shaft 9 the other of the electric motors 4 is attached, rotates the second encoder field 41 together with this wave 9 , whereby the angular position of the second encoder field 41 opposite the stationary to the chassis 2 of the vehicle 1 held second sensor 42 changed. The second sensor 42 can be analogous to the first sensor 39 be constructed so that the second sensor 42 a second encoder signal 43 can output that then from the angular position of the shaft 9 the other of the two electric motors 4 depends on or directly indicates.

The two encoder signals 40 . 43 can then in a common, only schematically indicated signal processing circuit 44 in the angular position 30 the waves 9 their electric motors 4 be converted insofar as they do not already indicate this in a suitable form. With the angular position 30 then can the electric motors 4 be controlled in the manner already carried out.

To avoid the two encoder signals 40 . 43 the sensor 42 . 39 on the corresponding opposite top 35 . 34 affect and thus the detected angular position 30 can falsify, between the two surfaces 35 . 34 a screed plate 45 be formed, the example in 6 is shown.

Alternatively or additionally, the two sensors 39 . 42 also on in 7 shown paragraph elements 46 be arranged, which are the sensors 39 . 42 also closer to the two donor elements 36 . 37 can introduce.

In addition, on the donor elements designed as magnets 36 . 37 , as in 8th shown on its the circuit carrier 33 opposite side return elements in the form of return plates 47 be arranged, reducing the field strength of the sensors 39 . 41 directed encoder field 38 . 41 can be raised.

Furthermore, the magnetic elements designed as donor elements 36 . 37 as in 8th be magnetized, the front side magnetized, whereby the number of poles of the donor elements is increased. In this way, the necessary magnetic field to carry out the angle measurement with the sensors 39 . 41 focused and thus compressed, reducing the magnetic field at the point of the sensor 39 . 41 is brought together more strongly.

Finally, the shape of the donor elements 36 . 37 arbitrarily executable. As in 9 shown in section, the donor elements 36 . 37 be designed, for example, annular, wherein the encoder field 38 . 41 of the respective donor element 36 . 37 to the inner diameter of the corresponding donor element 36 . 37 out and from the sensors 39 . 42 is detected.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2555417 A1 [0002]
• DE 102011080789 A1 [0030]

Claims (10)

Sensor ( 29 ) for outputting a first sensor signal ( 40 ) in dependence on a first angular position ( 30 ) of a first wave ( 9 ) of a first electric motor ( 4 ) and a second sensor signal ( 43 ) as a function of a second angular position ( 30 ) a second wave ( 9 ) of a second electric motor ( 4 ), comprising: - a first sensor ( 39 ) for detecting a stationary with the first wave ( 9 ) excited the first donor field ( 38 ) and to output the first sensor signal ( 40 ) depending on the detected first encoder field ( 38 ), - a second sensor ( 42 ) for detecting a stationary with the second wave ( 9 ) excited the second encoder field ( 41 ) and to output the second sensor signal ( 43 ) depending on the detected second encoder field ( 41 ), and - a circuit carrier ( 33 ), on which the first sensor ( 39 ) and the second sensor ( 42 ) are arranged jointly directed in different Sensierrichtungen. Sensor ( 29 ) according to claim 1, wherein both sensors ( 39 . 42 ) directed in opposite Sensierrichtungen on the circuit carrier ( 33 ) are arranged. Sensor ( 29 ) according to claim 1 or 2, comprising a shielding element ( 45 ) between the two sensors ( 39 . 42 ), which is the first donor field ( 38 ) and the second encoder field ( 41 ) corresponding to the second sensor ( 39 ) and the first sensor ( 42 ) shields. Sensor ( 29 ) according to one of the preceding claims, wherein at least one of the two sensors ( 39 . 42 ) on a paragraph element ( 46 ), over which the two sensors ( 39 . 42 ) are spaced from each other. Sensor ( 29 ) according to one of the preceding claims, wherein the two sensors ( 39 . 42 ) are magnetoresistive sensors. Sensor ( 29 ) according to one of the preceding claims, comprising a first transmitter element ( 36 ) for dispensing the first encoder field ( 38 ) and a second donor element ( 37 ) for dispensing the second encoder field ( 41 ), wherein the circuit carrier ( 33 ) with the two sensors ( 39 . 42 ) between the two encoder elements ( 36 . 37 ) is arranged. Sensor ( 29 ) according to claim 6, comprising a first return element ( 47 ) and a second conclusion element ( 47 ) corresponding to the first and second encoder field ( 38 . 41 ) on the first and second encoder element ( 38 . 41 ) on a circuit carrier ( 33 Short circuit) opposite side. Sensor ( 29 ) according to claim 6 or 7, wherein the first and second donor element ( 36 . 37 ) Are magnets that are connected to the sensors ( 39 . 42 ) directed side are magnetized. Drive ( 31 ) for a vehicle ( 1 ) with a first wheel ( 3 ) and a second wheel ( 3 ), which axially opposite a chassis ( 2 ) are movably supported on a ground comprising: - a first electric motor ( 4 ) with a first stator ( 16 ), one rotatable in the first stator ( 16 ) mounted first rotor ( 17 ), via a first magnetic drive field in an air gap between the first stator ( 16 ) and the first rotor ( 17 ), - a second electric motor ( 4 ) with a second stator ( 16 ), one rotatable in the second stator ( 16 ) mounted second rotor ( 17 ) via a second magnetic drive field in an air gap between the second stator ( 16 ) and the second rotor ( 17 ), - a first control device ( 26 ) for generating the first magnetic drive field based on an angular position ( 30 ) one non-rotatably with the first rotor ( 17 ) connectable and the first wheel ( 3 ) driving shaft ( 9 ), - a second control device ( 26 ) for generating the second magnetic drive field based on an angular position ( 30 ) one non-rotatably with the second rotor ( 17 ) connectable and the second wheel ( 3 ) driving shaft ( 9 ), and - a sensor ( 29 ) according to one of the preceding claims for detecting the rotational positions ( 30 . 30 ) of the first and second wave ( 9 . 9 ). Vehicle ( 1 ) comprising a chassis ( 2 ), which at least on a first wheel ( 3 ) and a second wheel ( 3 ) is movably carried on a ground and a drive ( 31 ) according to claim 9 for driving the two wheels ( 3 . 3 ).

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