WO2018193115A1

WO2018193115A1 - Sensor head, combination sensor, torque measuring arrangement, and method for measuring torque and rotational speed

Info

Publication number: WO2018193115A1
Application number: PCT/EP2018/060232
Authority: WO
Inventors: Christoph Schanz
Original assignee: Trafag Ag
Priority date: 2017-04-20
Filing date: 2018-04-20
Publication date: 2018-10-25
Also published as: DE102017108471A1

Abstract

The aim of the invention is to significantly broaden the scope of application of a torque sensor (26) in a cost-effective manner and with simple means. In order to achieve said aim, the invention provides a sensor head (48) for a torque sensor (26) for detecting a torque of a rotary shaft (32), wherein the sensor head (48) comprises: at least one magnetic field generating device (50) for generating a magnetic field in the rotary shaft (32) and at least one torque magnetic field detection device (52) for measuring at least one parameter of the generated magnetic field in the rotary shaft (32) in order to derive therefrom a torque applied on the rotary shaft (32), as well as at least one separate surface-marking detection device (110), which is spaced apart from the torque magnetic field detection device (52), for detecting a surface marking (36) on the surface of the rotary shaft (32) in order to determine a rotational speed of the rotary shaft (32). The invention also relates to a combination sensor (S1), to a torque measuring arrangement (22) and to a measurement method using the sensor head (48).

Description

SENSOR HEAD, COMBINATION SENSOR, TORQUE MEASURING ARRANGEMENT AND METHOD OF MEASURING

TORQUE AND SPEED.

The invention relates to a sensor head for a torque sensor for

Detecting a torque of a rotary shaft, wherein the sensor head comprises: at least one magnetic field generating means for generating a

Magnetic field in the rotary shaft and at least one torque magnetic field detecting means for measuring at least one parameter of the generated magnetic field in the rotary shaft to derive therefrom a voltage applied to the rotary shaft torque. Furthermore, the invention relates to a sensor comprising such a sensor head. Furthermore, the invention relates to a torque measuring arrangement comprising such a sensor head and the

having measuring rotary shaft. Finally, the invention relates to a method for measuring torque.

From DE 30 31 997 A1 and EP 0 046 517 A1 are methods and

Devices for non-contact measurement of static and dynamic

Torques on a rotary shaft by detecting a change in permeability of a ferromagnetic rotary shaft known. The combination of the rotary shaft and a torque sensor also discloses a torque measuring arrangement.

The object of the invention is to significantly improve the application possibilities of such torque measurements with cost-effective and simple means.

This object is achieved by a sensor head having the features of claim 1. Advantageous uses thereof are the subject of Besides claims. Advantageous embodiments are the subject of

Dependent claims.

The invention provides, in one aspect thereof, a sensor head for a torque sensor for detecting a torque of a rotary shaft, the sensor head comprising:

at least one magnetic field generating device for generating a

Magnetic field in the rotary shaft and at least one torque magnetic field detecting means for measuring at least one parameter of the generated magnetic field in the rotary shaft to derive therefrom a torque applied to the rotary shaft, and at least one of the torque-magnetic field detecting means spaced apart

Surface mark detecting means for detecting a

Surface marking on the surface of the rotary shaft to make a

To detect the rotational speed of the rotary shaft.

It is preferable that the surface mark detecting means comprises a distance detecting means for detecting a distance to the surface of the rotating shaft, the distance detecting means therefor

is formed to detect changes in a distance to the surface of the rotary shaft to a rotation of the rotary shaft formed by a change in the shape of the surface of a marking region of the rotary shaft

To detect surface marking, so as to detect the speed.

It is preferable that the surface mark detecting means comprises a rotational speed magnetic field detecting means, in particular for forming the

Distance detection device comprises.

It is preferred that the magnetic field generating device has at least one exciter coil.

It is preferable that the torque magnetic field detection means comprises at least one torque detection coil. It is preferable that the rotational speed magnetic field detecting device has at least one rotational speed sensing coil which is in an orientation direction of the

Sensor head, which is to be arranged in operation parallel to the axis of rotation of the rotary shaft, spaced from the at least one torque-measuring coil is arranged.

It is preferred that the excitation coil and the at least one torque measuring coil by at least one torque-measuring magnetic yoke for

Flow amplification for forming at least one torque-measuring magnetic circuit are connected.

It is preferable that the exciting coil and the at least one rotational speed measuring coil are connected by a rotational speed measuring magnetic yoke for flux amplification for forming a rotational speed measuring magnetic circuit.

It is preferable that the torque magnetic field detecting means comprises a first magnetic field measuring unit configured to detect a magnetic field at a torque measuring area of the surface of the rotating shaft in a first direction, and a second magnetic field measuring unit thereto

is configured to detect a magnetic field at a torque measuring range of the surface of the rotary shaft in a different direction from the first direction of the second direction.

Preferably, the first and second directions are at an angle to each other that is between 10 ° and 170 °, preferably between 45 ° and 135 °, and more preferably between 85 ° and 95 °.

Preferably, at least one or both of the first and second directions are relative to the orientation direction in which the

Surface marker detecting device of the

Torque magnetic field sensing device is spaced at an angle of between 10 ° and 170 °, more preferably between 25 ° and 65 ° and more preferably between 30 ° and 50 °. It is preferable that the first magnetic field measuring unit is a pair of first

Has torque measuring coils.

It is preferred that the second magnetic field measuring unit has a pair of second torque measuring coils.

It is preferred that the torque measuring coils are arranged in a star shape around a centrally arranged exciter coil of the magnetic field generating device.

It is preferable that the torque sensing coils and the exciting coil are connected by a common flux concentrator core of ferromagnetic material for forming flux concentrators for the first magnetic field measuring unit and the second magnetic field measuring unit.

It is preferable that the flux concentrator core has a cantilever extending in the orientation direction and through the rotational speed sensing coil.

It is preferred that the coils are designed as planar coils.

It is preferred that the planar coils on a common

Printed circuit board element are formed, on which a ferromagnetic material for forming a flux concentrator is arranged.

According to a further aspect, the invention provides a combination sensor for measuring torque and rotational speed on a rotary shaft, comprising a sensor head according to one of the preceding embodiments and an evaluation device, which is connected to the torque magnetic field detecting means to generate a torque indicative torque signal, and is connected to the surface mark detecting means to generate a rotational speed indicative speed signal.

It is preferred that the evaluation device is designed to detect the rotational speed detected by means of the sensor head and that of the sensor head detected torque to generate the current power indicative power signal.

In another aspect, the invention provides a

A torque measuring device comprising a rotating shaft and a sensor head according to any one of the preceding aspects and / or a combination sensor according to any one of the preceding embodiments, wherein the rotating shaft has a torque measuring section with a circular cylindrical surface on which the torque magnetic field detecting device is disposed and axially adjacent thereto a surface-marking marking section in the form of a deviating from a circular cylindrical surface surface shape.

It is preferred that the marking area comprises a sprocket.

In another aspect, the invention provides a method of measuring torque and rotational speed on a rotary shaft, comprising:

a) Providing the rotary shaft with a marking area on which a non-rotationally symmetric surface marking is attached and an axially spaced torque measuring area without surface marking

b) generating a magnetic field at the surface of the rotary shaft,

Measuring magnetic field changes based on applied to the rotary shaft forces on the torque measuring range by means of a torque magnetic field detecting device and

c) detecting the passage of the surface marking upon rotation of the rotary shaft by means of a arranged on the marking area

Surface marking detection means.

It is preferred that step a) comprises: providing the

Surface marking such that it requires a deviating from a circular cylindrical shape surface shape and

in that step c) comprises: detecting the distance of the surface of the rotating shaft from the surface mark detecting means. It is preferred that step b) comprises: generating a magnetic field both in the torque detection region and in the adjacent marking region by means of a common magnetic field generation device and

in that step c) comprises: measuring a magnetic field change resulting from passing the surface mark.

It is preferred that in the method a sensor head and / or a sensor and / or a torque measuring arrangement according to one of the preceding embodiments is used.

A preferred embodiment of the torque measuring arrangement is provided with a rotary shaft and a torque sensor for measuring a torque on the rotary shaft by inductively measuring the torque of the rotary shaft by means of alternating magnetic fields and with an evaluation device for evaluating the signal of the torque sensor, wherein the rotary shaft

Surface marking at a marking area adjacent to that detected by the torque sensor for torque measurement

Has circumferential area, wherein the surface marking rotates about the axis of rotation upon rotation of the rotary shaft and when passing a on the

Torque sensor surface marking detection device causes a corresponding to the rotational frequency changing speed signal, wherein the evaluation device is adapted to from the speed signal at least one, several or all of the parameters speed,

To determine the rotational speed, direction of rotation and / or rotation angle of the rotary shaft.

It is preferred that the surface marking comprises an axially extending flattening, indentation or elevation on the surface of the peripheral region. Particularly preferred is an arrangement of teeth, in particular in the form of a ring gear provided.

It is preferred that the torque sensor comprises a sensor head provided with at least one magnetic field generating device for generating an alternating magnetic field in the rotary shaft and with at least one Magnetic field detection device is provided for measuring at least one parameter of the alternating magnetic field in the rotary shaft.

It is preferable that the magnetic field generating device has at least one flux concentrator with at least one magnetic field generating coil and one soft magnetic core, and that the magnetic field detecting device has a plurality of measuring coils for measuring different magnetic field orientations. Preferably, a torque sensor is used, as described in its basic structure in DE 30 31 997 A1, EP 0 046 517 A1 or US Pat. No. 4,503,714. These documents are in more detail

Details of the torque sensor incorporated by reference. In addition to the known structure for measuring the torque, the sensor proposed here has a separate one

Surface mark detection device on.

It is preferred that the evaluation device has a counting device for counting the number of signal changes and / or detecting a rotation angle. Thus, e.g. be counted by teeth of a ring gear signal pulses to a rotation angle or additional

Considering the time to determine a rotational speed.

It is preferred that the evaluation device a

Signal change distance detecting means for detecting the distance between the generated by passing the surface mark

Signal changes and / or for detecting a speed per time.

It is preferred that the evaluation device has a frequency detection device for detecting the frequency of the changes in the rotational speed in order to determine therefrom the rotational speed of the rotational shaft and / or the rotational speed at the surface of the rotational shaft.

It is preferred that the evaluation device is designed to detect a pulse shape of the signal change and to detect therefrom the rotational speed on the surface of the rotary shaft and / or the direction of rotation. It is preferred that the evaluation device a

Pulse width detection device for detecting a pulse width of

Signal change and / or for determining the rotational speed of a width of the signal change.

It is preferred that the surface marking has a surface shape which is asymmetrical with respect to a center axis running in the axial direction and / or that a plurality of the surface markings are provided with irregular distances and / or with an axisymmetric arrangement extending in the axial direction, wherein the evaluation device is designed to determine the direction of rotation from a slope of a pulse edge of the signal change and / or from a distance sequence between signal changes.

In particular, a corresponding tooth shape of the teeth of a ring gear can be provided. Particularly preferably, the teeth have different

Flank forms on both sides.

The rotary shaft is preferably formed at least on its surface or even entirely of a soft magnetic or ferromagnetic material. In this case, preferably a change in permeability is changing

Torque load recorded. This is preferably done by means of magnetic fields generated by a magnetic field generating device in the ferromagnetic material and detecting the forming magnetic fields - in particular density and orientation of the field lines - by means of a

Magnetic field detector. The magnetic field detection device has e.g. a plurality of intersecting magnetic circuits partially passing through the rotary shaft and partially passing through first and second yoke sections of a

Sensor head run. In less preferred embodiments, a rotating shaft permanently magnetized at least on its surface is used.

According to a further aspect, the invention relates to a method for

simultaneous detection of a torque and at least one of the parameters rotational speed, rotational angle, rotational speed or direction of rotation on a rotary shaft formed from or with a soft-magnetic material, comprising: Providing a surface marking on a sector of a first

Peripheral portion of the rotary shaft;

Generating an alternating magnetic field in the rotary shaft at the first peripheral portion and an axially adjacent second peripheral portion;

Measuring the torque by detecting at least one of the

magnetoelastic effect influenced parameter of the generated alternating magnetic field by means of at least one magnetic field detecting means on the second peripheral region and generating a signal from the detection of the parameter,

Detecting a magnetic field change at the first peripheral region, which is generated by the surface marking another

Magnetic field detection device happens and

Evaluating the magnetic field change at the first circumferential region to detect at least one of the parameters rotational speed, rotational angle, rotational speed or direction of rotation.

According to a further aspect, the invention relates to a

A torque control device for controlling the output and / or the torque of an electric drive comprising an electric motor with stator and rotor and a common rotation with the rotor

Output shaft has as a rotary shaft, comprising:

a torque measuring arrangement according to one of the preceding

Embodiments for measuring a torque on the output shaft and a controller connected to the torque measuring device, which is adapted to control the electric motor in dependence on the torque measured by the torque sensor.

It is preferred that the controller is adapted to control the electric motor in dependence on the torque measured by the torque measuring arrangement and the rotational speed determined by the torque measuring arrangement, the controller being adapted to supply the output power of the electric drive from the torque and the rotational speed determine and control the electric motor in dependence on the determined output power. According to a further aspect, the invention relates to an electric drive, comprising a torque control device according to one of the preceding embodiments and / or a torque measuring arrangement according to one of the preceding embodiments.

A basic idea of the invention is, taking advantage of a permeability change of rotating shaft formed from ferromagnetic materials and of

Surface effects to form a combination sensor, which detects not only torque but also at least one other parameter of the rotational movement of the rotary shaft, preferably with the same measurement structure. Particularly preferably, a torque signal and a rotational speed signal are generated in the same measurement setup by different measuring coils spaced apart from one another and output via separate channels. Thus, one can arrange the speed measuring coil on a marking region of the rotary shaft, which has an optimized for a speed detection surface shape or material distribution, while a

Torque measuring coil or a torque-measuring magnetic field detection device with a plurality of torque measuring coils can arrange on a torque measuring range of the rotary shaft, which has optimized for the torque measurement surface shape and material distribution - in particular as uniformly as possible over the entire circumference - has.

In particular, so independent signals for speed and torque with high resolution can be achieved with the same simple measurement setup.

In particular, the application is in conjunction with an electric motor

Interesting. The detected torque and the at least one more

Parameters can be used for controlling and / or regulating the electric motor. It can e.g. an exact torque control or

Power regulation. Also, the rotation angle can be detected and so easily a servo motor or servo motor can be created, which can be moved with exact torque in a predetermined position. So very powerful actuators can be created.

But there are also many other applications possible, for example, other drives, eg with an internal combustion engine, a pneumatic or hydraulic drive are provided with the torque measuring arrangement to monitor and / or control the torque outputs and / or rotational speed and / or the travel.

A preferred application relates to an apparatus and method for controlling the output and / or torque of an electric drive having an electric motor with stator and rotor and an output shaft connected to the rotor for common rotation.

In previously available on the market power electronics for electric drives can by measuring the phase currents and phase voltages the

Power consumption of an electric motor are measured relatively accurately. By appropriate models for efficiency and various dependencies (temperature dependence, aging behavior ...), the output power can be calculated. With these sizes, electric motors can be controlled to a specific torque at a known angular velocity of the axis. Such electric drives and their torque control devices can be found, for example, in available on the market main electric drives for electric vehicles.

An example of a known regulation of an electric drive in the field of electric steering systems can be found in US 2005/037884 A1.

An advantage of a particular embodiment of the invention is that such devices and methods for torque control and / or regulation of the power of electric drives with respect to the accuracy of the output torque or output power and / or in terms

Safety aspects can be improved.

A preferred application of the invention relates to a

Output shaft has, comprising: a torque sensor for measuring a torque on the output shaft and a controller connected to the torque sensor, which is adapted to the electric motor depending on the

Torque sensor to control measured torque.

In particular, this allows a torque-controlled electric motor

whose regulation is not by voltage / current, but by an active sensor element.

A preferred embodiment of the invention is characterized by a speed sensor for measuring the rotational speed of the output shaft, wherein the

Control is connected to the speed sensor and is adapted to the electric motor in response to the by the torque sensor

measured torque and the speed connected by the speed sensor.

It is preferred that the controller is adapted to determine the output power of the electric drive from the torque and the speed and to control the electric motor in dependence on the determined output power.

It is preferred that the control for monitoring the power output of the electric drive is set up.

It is preferred that the controller is adapted to the electric drive depending on an input power determined from an input current and an input voltage and one determined from the torque

Output power and a target power to control and / or monitor.

Especially for electromobility there is a requirement (SIL2 according to EN61508 and / or Performance Level d according to ISO 13849-1) that the output power of the electric motor is monitored. This can be done with voltage / current. Much more accurate, however, this is by direct monitoring via direct sensors on the output shaft, as proposed in the invention. Particular advantages has the inventive idea, if the electric drive you for a Torque vectoring is regulated to the torque. In such a case, an active sensor element as proposed in the invention is very advantageous because you can not regulate both voltage / current and this size can also use for security monitoring.

It is preferred that the torque sensor is an inductive non-contact sensor for inductive torque detection directly on the output shaft by means of alternating magnetic fields. Such sensors are very easy to use on the output shaft, wherein the output shaft can remain unchanged and no active elements in the co-rotating system are needed. The non-contact measurement takes place without friction losses and is essentially maintenance-free.

With a torque measuring arrangement according to an advantageous embodiment of the invention, one can simultaneously with a signal the torque of the rotary shaft (for example the output shaft) and with another signal e.g. determine their speed. Thus, one can directly determine the mechanical power at the rotary shaft with signals generated by a single sensor head and yet independent. This is of course highly interesting for the control of electric drives, but can also be used for other uses. For example, For example, different applications (cars, trucks, ships, machinery, aircraft, vehicles) on an output shaft could directly measure mechanical performance.

Preferably, the torque measuring arrangement is designed for use in a torque control according to one of the previously explained embodiments, wherein the output shaft of the rotating shaft to be measured

Torque measuring arrangement is. However, the torque measuring arrangement is also suitable and advantageous for other purposes, where in addition to the measurement of a torque of a rotary shaft and their speed should be determined.

According to a further aspect, the invention provides a control method for regulating the output power and / or the torque of an electric drive, comprising an electric motor with stator and rotor and an output shaft connected to the rotor for common rotation, comprising:

Measuring a torque on the output shaft by means of a

Torque sensor,

Measuring the speed of the output shaft and

Controlling the electric motor in dependence on the by the

Torque sensor measured torque and the speed determined by the speed sensor.

A preferred embodiment of the control method comprises:

Determining the output power of the electric drive from the torque and the speed and

Controlling the electric motor as a function of the determined output power.

A preferred embodiment of the control method comprises:

Monitoring the power output of the electric drive by means of

Output power, the input power determined from an input current and an input voltage, and a target power.

A preferred embodiment of the control method comprises:

Non-contact inductive measuring of the torque at the output shaft by means of magnetic alternating fields.

A preferred embodiment of the control method comprises:

Using an output shaft having a surface mark on a first detected by the combination sensor peripheral portion which rotates upon rotation of the output shaft about the axis of rotation and upon passing a provided for surface mark detection portion of the combination sensor causes a change in a first signal of the torque sensor, and determining the Speed of the output shaft from the period of change of the first signal of the combination sensor.

A preferred embodiment of the control method comprises: Providing an axially extending flattening, indentation or elevation on the surface of the first peripheral region to form the surface marking.

A preferred embodiment of the control method comprises:

Providing the surface marking with a predetermined extent in the circumferential direction and

Determining the rotational speed of the length of a through the

Surface marking in the signal of the torque sensor caused signal change. For example, a sprocket with over a

predetermined length of circumferentially extending teeth are provided, and the rotation angle and the rotation speed can be detected by counting pulses correspondingly caused by the teeth in the speed signal.

An advantageous application of the invention relates in particular to a

Torque control of an electric motor or for an electric motor.

A preferred embodiment relates to a torque control of a

Electric motor by measuring the output power by means of a preferably combined torque sensor and speed sensor. As a result, a very accurate control is possible.

Preferably, the apparatus and method additionally or alternatively comprises monitoring the engine output as

Safety monitoring by means of the input power (voltage, current).

This makes a very good safety monitoring possible for torque-controlled electric motors. By determining the actual output power determined via measured torque and measured speed

Regeleingangsgrößen, you can see the voltage and current as additional variables for other tasks, in particular the

Use safety monitoring. You can also by comparison determine the degree of efficiency and the power loss without detours by considering further parameters (such as environmental conditions).

An advantageous application is explained below: The use of electric motors in electromobility classifies their function as safety-critical, i. the power output should be monitored in a safety function. This monitoring can be implemented by means of current and voltage. With an active control of the output power of the electric motor (torque vectoring, anti-slip regulation ....) on the shaft of a drive, it requires a second measuring device for the active control to the

To be able to continue to use function monitoring by means of voltage and current as an independent variable outside the control loop. According to an advantageous embodiment of the invention for this purpose a direct measurement of the torque and possibly the speed is proposed at the output shaft.

Another particularly preferred use of the here

described sensor head described here

Torque measuring arrangement and the sensor described here is the

Performing a power measurement.

For a power measurement, the torque and the speed /

Rotational speed needed. A particularly preferred embodiment of the invention describes an arrangement for a torque sensor and a speed sensor which operates on a similar technological basis as the speed sensor and the combination of both in a package.

Preferably, a magnetic field is coupled by a generator with an excitation coil in the measuring shaft and used for the torque measurement.

Particularly preferred for torque measurement, an arrangement of a central excitation coil and two pairs of measuring coils arranged on 5 pins of a ferromagnetic core used. Via a 6th pin in the

ferromagnetic core (eg ferrite), an additional speed measuring coil is coupled into the magnetic circuit. Particularly preferably, the speed measuring coil is located above a

Sprocket pattern, which is embossed in the measuring shaft. The height-depth profile of the sprocket changes the inductance of the speed measuring coil, resulting in a variation in the signal of the speed measuring coil

(= Speed signal) expresses.

For example, with 32 teeth in the ring gear on the measuring shaft 64 angular units can be resolved. With good mechanical processing of the sprockets or execution in a sinusoidal course significantly higher resolutions can be achieved. For example, With different edge shapes of the teeth on the front and back, the direction of rotation can be detected.

Also conceivable is any other variant for a rotation angle and

Speed sensor with the torque sensor as a power sensor.

The sensor head is preferably designed as a sensor package, as described and shown in German Patent Application 10 2016 122 172.4. Accordingly, coils are preferably designed as planar coils on a substrate, in particular in printed circuit board technology, as described in more detail in this

Patent Application 10 2016 122 172.4 is described. It will be for more

For details on the manufacture of the sensor head expressly refer to DE 10 2016 122 172.4.

An embodiment will be explained in more detail below with reference to the accompanying drawings. It shows:

1 shows a schematic representation of a torque measuring arrangement with a rotary shaft and a sensor which has a sensor head arranged on the rotary shaft;

Fig. 2 is a schematic representation of an electric drive with a

Electric motor as an example of an application of the

Torque measuring device; and the electric drive of Fig. 2 with a torque control device for controlling the torque and / or the output power of the electric motor.

1, a torque measuring assembly 22 is shown having a rotary shaft 32 and a torque sensor 26 for measuring torque on the rotary shaft 32.

The torque sensor 26 is designed as a non-contact magnetoelastic sensor S1, which operates with alternating magnetic fields. For further details on such sensors reference is made to the following references:

[1] Lutz May, "Torque as easy as measuring temperature" in

Buying Metrology & Sensor Technology 2015;

[2] Gerhard Fiedler, Franz Merold "Intelligent Sensors -

Magnetorestrictive Torque Sensors "in Elektronik Journal 04/2016;

[3] H. Ruser, U. Troltzsch, M. Horn, H.-R. Tränkler; "Magnetic

Torque measurement with low-cost sensor "downloaded on

02.06.2016 under

http://www.mikrocontroller.net/attachment/22413/Trehmomentsensor- Kreuzspule.pdf; Lecture VDE / VDI Symposium 1 1. and March 12, 2002, Ludwigsburg, see also references in this document;

[4] WO2015 / 001097 A1.

[5] DE 30 31 997 A1

[6] EP 00 46 517 A1

[4] US 4 503 714 A

The sensor S1 is preferably non-contact based on the inductive

Measuring principle executed, see [3], [2], [5] - [7]. As stated in [4], the sensor S1 is operated with an alternating magnetic field. The advantage here is the operation in an active mode; Thus, the fast magnetic alternating field requires no physical change to the rotary shaft 32, a permanent and possibly not long-term stable magnetization is not required, see [1]. The methodology is insensitive to contamination (water, oil, dust), vibration, air gap change and can not be damaged if excessive forces act on the rotary shaft 32, since the sensor S1 is outside the power flow.

The torque sensor 26 has a sensor head 48.

At the sensor head 48, the torque sensor 26 has a

Magnetic field generating means 50 for generating a magnetic field in and on the rotary shaft 32 and a torque magnetic field detecting means 52 for measuring changes of the magnetic field on the rotary shaft 32 for the purpose

Generation of an applied torque indicative torque signal.

As part of these devices 50, 52, the sensor head 48 has a designated here as the core body 54 of soft magnetic material to the

Rotary shaft 32 directed toward projections 56, 57 a, 57 b, 57 c, 57 d, which are each surrounded by coils 58-62.

Thus, a central fifth projection 56, which is surrounded by an excitation coil 48 connected to an electric oscillation generator (not shown, may be part of an electronics 80) and designed to generate magnetic fields, forms part of a flux concentrator 66, with which the

Focusing magnetic flux of the indexed in the rotary shaft 32 magnetic field.

A first projection 57a surrounded by a first torque measuring coil 59 and a second projection 57a surrounded by a second torque measuring coil 60

Projection 57b are part of a first torque-measuring magnetic circuit 70, and a third projection 57c surrounded by a third measuring coil 61 and a fourth projection 57d surrounded by a fourth measuring coil 62 are part of a second torque-measuring magnetic circuit 72. For this purpose, the projections 57a-57d are arranged in pairs opposite one another so that the pairs intersect. Due to the different angles of the two magnetic circuits 70, 72 magnetic field direction changes can be detected. The corresponding between the first projection 57 a and the second

Projections 57b extending and extending between the third projection 57c and 57b areas of the flux concentrator 66 act as torque-measuring magnetic yokes 74, 76 for forming the corresponding torque-measuring magnetic circuits 70, 72, which at an angle between 10 ° and 170 °, in particular between 45 ° and 135 ° to each other. Particularly preferred are angles in the range of 90 °.

Thus, a first magnetic field measuring unit 102 and a second magnetic field measuring unit 104 are formed by the two differently oriented torque-measuring magnetic circuits 70, 72, which can detect magnetic fields of different directions generated at a torque measuring area 106 of the rotary shaft 32.

The torque measuring coils 59-62 are connected to a torque evaluation unit 30. The torque evaluation unit 30 may be part of a

Evaluation device 100 and e.g. be designed as software in an electronics 80 on a module 78 on a circuit board element 130 of the sensor S1. The torque evaluation unit 30 delivers a torque signal M by evaluating the signals A1, A2, B1, B2 of the torque measuring coils 59-62. In particular, angular changes in the induced magnetic field resulting from the magnetoelastic effect upon the occurrence of a torque can be detected, e.g. by taking a difference between the signals A and B of the pairs of torque measuring coils 59-62, in particular by

M = A-B = (A1 + A2) -B1 + B2),

where M is the torque signal, A = A1 + A2 is the signal of the first

Magnetic field measuring unit 102 which is the sum of the signal A1 from the first torque measuring coil 59 and the signal A2 from the second

Torque measuring coil 60, and B = B1 + B2 is the signal of the second magnetic field measuring unit 104, which is the sum of the signal B1 from the third torque measuring coil 61 and the signal B2 from the fourth

Torque measuring coil 62 represents. The torque magnetic field detector 52 otherwise operates to detect the torque as known from the aforementioned literature.

Further, on the sensor head 48 a

Surface mark detecting means 1 10 is provided, by means of which it is detected whether a surface marking 36, which is provided in a marking region 1 12 on the surface of the rotary shaft 32 passes the sensor head 48 upon rotation of the rotary shaft 32. As a result, the sensor S1 can be used not only as a torque sensor 26 but also as a rotational speed sensor 28, and is thus configured as a combination sensor capable of outputting both a torque signal and a rotational speed signal.

In this case, the surface mark detection device 1 10 in one

Orientation direction 1 14 of the sensor head 48, which is to be aligned in operation parallel to the rotational axis of the rotary shaft 32, spaced from the torque magnetic field detection means 52 arranged. The torque magnetic field detecting device 52 is disposed axially on the torque measuring portion 106 of the rotary shaft 32, which is formed circular cylindrical shape with a rotationally symmetrical surface shape and material distribution as possible. The marking area 1 12 of the rotary shaft 32 is adjacent to the

Torque measuring range arranged and with the at least one

Surface marking 36 provided by the

Surface marker detection device 1 10 can be detected.

The type and accordingly the detection of the surface marking 1 10 may be different. Particularly preferably, the

Surface marker detecting device a

Distance detection device 1 16, by means of the distance to the

Surface of the marking region 1 12 of the rotary shaft 32 is detectable, wherein the surface marking 36 is formed by a variation of the distance. The distance detecting device 1 16 is in the preferred

Exemplary embodiment is formed in particular by a speed-magnetic field detection device 122 explained in more detail below. In the example shown in FIG. 1, a toothed rim 118 having a row of teeth 120 is provided for forming the surface marking 36. For example, 32 teeth and corresponding valleys are provided in between. The number of teeth 120 can of course be chosen differently depending on the desired resolution.

Particularly preferably, the surface mark detection device 1 10 has a further magnetic field detection device, which in the following to

Distinction from the above-described torque-detecting magnetic field detecting device 52 is referred to as a rotational speed magnetic field detecting device 122. The

Surface marking 36 is correspondingly designed such that it is magnetically detectable. This can be done in different ways

happen, but preferably by the already described variation of the distance to the rotational speed magnetic field detection device 122nd

The rotational speed magnetic field detecting device 122 has a rotational speed measuring magnetic yoke 124, which is substantially by a in the

Orientation direction 1 14 extending arm 125 of the core or body 54 is formed of soft magnetic material. The arm 125 has a sixth protrusion 126 directed toward the rotary shaft 32 - the protrusions may also be referred to as a PIN - around which a sixth coil is arranged, which is used as a fifth measuring coil in the form of a speed measuring coil 128 and with the evaluation device is connected to form a speed signal.

As a result, a third magnetic circuit 132 is formed, which extends from the central fifth projection 56 of the body 54 or flux concentrator 66 in the axial direction in the rotary shaft 32 to the marking area 1 12 and from there through the sixth projection 126 and the arm 125 back ,

In the embodiment shown in Fig. 1 is for forming the

Surface marking 36 as mentioned above, the sprocket 1 18 provided. Due to the change in the distance of the surface of the rotary shaft 32 to the speed measuring coil 128 and its sixth projection 126, the inductance of the speed measuring coil 128 changes as a result of the height-depth profiles of the toothed rim pattern varied by the sprocket pattern distance the signal of the speed measuring coil 128th

In the evaluation device 100 is from the variation of this signal the

Speed measuring coil 128 in a corresponding e.g. Software implemented speed evaluation unit 134 determines the speed n and / or the rotational speed. By counting corresponding pulses of this signal, the relative rotation angle can also be determined. Will the respective teeth 120

asymmetrical, e.g. by different edge shapes or by different distances to each other, you can detect the direction of rotation due to the waveform.

The production of the sensor head 48 is preferably carried out in the same manner as described and shown for a sensor head without cantilever in German Patent Application 10 2016 122 172.4. Accordingly, the first to sixth coils 32, 59-62, 128 are formed as planar coils on a substrate.

In particular, a printed circuit board element 130 is provided, on which the

Planar coils are formed and corresponding contacts are formed to the signal line. The evaluation device 100 can also be realized on the printed circuit board element 130, as indicated by the electronics 80. Also, soft magnetic material for forming the body 54 including cantilever 125 and the first to sixth projections 56, 57a-57d, 126 may be prepared in a similar manner as described in 10 2016 122 172.4.

The sensor S1 thus supplies a torque signal M on a first channel and a speed signal n on a second channel

Combination sensor designed to measure torque and speed. Particularly preferably, the sensor S1 is designed as a power sensor L for measuring a mechanical power on the rotary shaft 32, wherein the power, such as in the following with reference to FIGS. 2 and 3 with reference to a

Usage example, e.g. in the evaluation device 100, from the torque signal M and the rotational speed signal n is determined.

In Fig. 2, an electric drive 10 is shown schematically, which is here by an electric motor 12 with stator and rotor (not shown in detail, well known) is formed. A shaft of the rotor forms an output shaft 14 of the electric drive 10. In other embodiments (not shown), the output shaft 14 is a shaft coupled to the shaft of the rotor for common rotation, e.g. an end shaft of an electric motor provided on the motor gear.

In electric motors so far the drive power P is only determined by the voltage U and the current I with P = U ^* l. However, this determines the input power Pin = U ^* l. In order to determine the output power, therefore, the power loss Pv had to be taken into account via model calculations.

For the mechanical output Pab we have: Pab = 2 ^* Pi ^* M ^* n, where M is the

Torque on the output shaft 12 and n denotes the rotational speed of the output shaft 14. So far, if one wanted to control the electric drive 10 in such a way that a constant output torque M is output, then the input power has been regulated according to the measured voltage U and the measured current I.

In Fig. 3, the electric drive 10 is shown with a torque control device 20. The torque control device 20 includes the

Torque measuring arrangement 22 and a controller 24, which with the

Torque measuring arrangement 22 is connected to control the electric motor 12 depending on a measured by the torque sensor 26 of the torque measuring device 22 torque M on the output shaft 14.

Further, the illustrated torque control device 20 includes the

Speed sensor 28 for detecting the speed n of the output shaft 14th Here, the sensor S1 is used as a combination sensor both as a torque sensor 26 and as a speed sensor 28. The signals for torque and

Speed can be provided on different channels. Nevertheless, they can be shared, simple and inexpensive

produce sensor head 48, and in such a way that they do not affect each other or only slightly.

In the application of the torque measuring arrangement 22 shown in FIG. 3, the rotary shaft 32 is equal to the output shaft 14 of the electric drive 10.

As explained above, a magnetoelastic non-contact sensor S1 using higher frequency alternating magnetic fields with transmitting coil and receiving coil is used, which serves both as a torque sensor 26 for

Detecting the torque M of the rotary shaft 32 and in Fig. 3 of the output shaft 14 of the electric drive 10, and as a speed sensor 28 for detecting the rotational speed n of the rotary shaft 32 and thus in Fig. 3 of the output shaft 14 of the

Electric drive 10 is used.

As can be seen in FIG. 3, the evaluation device 100 thus supplies the output torque M at the output shaft 14 as well as the rotational speed n of the output shaft 14, so that the output power Pab can be determined therefrom.

The controller 24, for example designed as a motor controller, controls the electric motor 12 as a function of the torque M thus determined or in dependence on the thus determined output power Pab. In particular, thereby the torque M and / or the output power Pab to a desired value, in particular a desired power P _S0 n (or a target torque) can be controlled.

Further, the controller 24 can realize both a control and a safety monitoring independently of the control due to the plurality of measured variables. For example, the electric motor 12 is regulated on the basis of the measured values M and n or Pab and the motor input power Pi is monitored via the motor current I and the motor voltage U for the safety shutdown. LIST OF REFERENCE NUMBERS

10 electric drive

12 electric motor

14 output shaft

20 torque control device

22 torque measuring arrangement

24 control

26 torque sensor

28 speed sensor

30 torque evaluation unit

32 rotary shaft

36 surface marking

48 sensor head

50 magnetic field generating device

52 torque magnetic field detection device

54 bodies of soft magnetic material

56 (fifth) lead (flux concentrator)

57a first projection (first magnetic circuit)

57b second projection (first magnetic circuit)

57c third projection (second magnetic circuit)

57d fourth projection (second magnetic circuit)

58 exciting coil (fifth coil)

59 first torque measuring coil

60 second torque measuring coil

61 third torque measuring coil

62 fourth torque measuring coil

66 flux concentrator

70 first torque measuring magnetic circuit

72 second torque-measuring magnetic circuit

74 first torque-measuring yoke

76 second torque-measuring magnetic yoke

78 block

80 electronics

100 evaluation device 102 first magnetic field measuring unit

104 second magnetic field measuring unit

106 torque measuring range (second circumferential range on the rotary shaft)

1 10 Surface marker detector

1 12 marking area (first circumferential area on the rotary shaft)

1 14 Orientation direction

1 16 distance detection device

1 18 sprocket

120 tooth

122 speed magnetic field detection device

124 Speed measuring yoke

125 outriggers

126 sixth lead

128 speed measuring coil (sixth coil, fifth measuring coil)

130 printed circuit board element

132 third magnetic circuit

134 Speed evaluation unit

L power sensor

S1 sensor (combination sensor: contactless speed sensor and

contactless torque sensor; Power sensor)

Claims

Trafag AG 1021 0058 P-WOIndustriestrasse 1 1 CH-8608 Bubikon Switzerland

1 . A sensor head (48) for a torque sensor (26) for detecting a torque of a rotary shaft (32), the sensor head (48) comprising:

at least one magnetic field generating means (50) for generating a magnetic field in the rotating shaft (32) and at least one torque magnetic field detecting means (52) for measuring at least one parameter of the generated magnetic field in the rotating shaft (32) to obtain therefrom

Rotate shaft (32) derived torque,

marked by

at least one separate surface mark detecting means (110) spaced from the torque magnetic field detecting means (52) for detecting a surface mark (36) on the surface of the rotating shaft (32) to determine a rotational speed of the rotating shaft (32).

2. sensor head (48) according to claim 1,

characterized,

in that the surface mark detection device (1 10) has a

Distance detection means (1 16) for detecting a distance to the surface of the rotary shaft (32), wherein the distance detecting means (1 16) is adapted to detect changes in a distance to the surface of the rotary shaft (32) to rotate upon rotation of the rotary shaft (32). 32) to detect a surface mark (36) formed by a change in the shape of the surface of a marking area (1 12) of the rotary shaft so as to determine the rotational speed.

3. sensor head (48) according to claim 1 or 2,

characterized,

in that the surface mark detection device (1 10) has a rotational speed Magnetic field detection device (122), in particular for forming the

Distance detection device (1 16), comprising.

4. sensor head (48) according to claim 3,

characterized,

in that the magnetic field generating device (50) has at least one exciter coil (58),

in that the torque magnetic field detection means (52) comprises at least one torque measuring coil (59-62),

in that the rotational speed magnetic field detection device (122) has at least one

A speed measuring coil (128) arranged in an orientation direction (1 14) of the sensor head (48), which in operation is parallel to the rotational axis of the rotary shaft (32), spaced from the at least one torque measuring coil (59-62). and that the exciter coil (58) and the at least one torque sensing coil (128) are arranged through at least one flux measuring torque yoke (74,76) for forming at least one of

Torque measuring magnetic circuit (70, 72) are connected and the exciter coil (58) and the at least one rotational speed measuring coil (128) by a speed-measuring magnetic yoke (124) for flux amplification to form a speed-measuring magnetic circuit (124 ) are connected.

5. sensor head (48) according to any one of the preceding claims,

characterized,

in that the torque magnetic field detection device (52) has a first

Magnetic field measuring unit (102) adapted to detect a magnetic field at a torque measuring area (106) of the surface of the rotary shaft (32) in a first direction, and a second magnetic field measuring unit (104) adapted to apply a magnetic field to the magnetic field Torque measuring range (106) of the surface of the rotary shaft (32) to detect in a different direction from the first direction of the second direction.

6. sensor head (48) according to claim 5,

characterized,

the first magnetic field measuring unit (102) has a first pair of torque Measuring coils (59, 60) and the second magnetic field measuring unit has a second pair of torque measuring coils (61, 62) and that the torque measuring coils (59-62) arranged in a star shape around a centrally arranged excitation coil (58) of the magnetic field generating device (50) are.

7. sensor head (48) according to claim 6,

characterized,

in that the torque measuring coils (59-62) and the exciting coil (58) are connected by a common body (54) of soft magnetic material for forming flux concentrators (66) for the first magnetic field measuring unit (102) and the second magnetic field measuring unit (104).

8. sensor head (48) according to claim 7 and claim 4,

characterized,

the body (54) of soft magnetic material has a cantilever (125) extending in the orientation direction (1 14) and further through

Speed measuring coil (128) extends.

9. sensor head (48) according to any one of claims 4 or 6 to 8,

characterized,

in that the coils (58-62, 128) are designed as planar coils.

10. sensor head (48) according to claim 9,

characterized,

in that the planar coils are formed on a common printed circuit board element (130), on which also a soft magnetic material for forming a flux concentrator (66) is arranged.

1 1. A combination sensor (S1) for measuring torque and rotational speed on a rotary shaft (32), comprising a sensor head (48) according to any one of the preceding claims and an evaluation device (100) connected to the torque magnetic field detecting device (52) for detecting the To generate torque indicative torque signal (M), and with the Surface mark detection means (1 10) is connected to generate a speed signal indicative of the rotational speed (n).

12. Combination sensor (S1) according to claim 1 1,

characterized,

in that the evaluation device (100) is designed to generate a power signal indicative of the instantaneous power from the rotational speed detected by means of the sensor head (48) and the torque detected by means of the sensor head (48).

13. torque measuring arrangement (22) having a rotary shaft (32) and a sensor head (48) according to one of claims 1 to 10 and / or a

Combination sensor (S1) according to claim 1 1 or 12, wherein the rotary shaft (32) has a torque measuring portion (106) with a circular cylindrical surface on which the torque magnetic field detecting means (52) is arranged, and axially adjacent thereto a marking region (1 12) at least one surface marking (36), in particular in the form of one of

circular cylindrical surface deviating surface shape, has.

14. torque measuring arrangement (22) according to claim 13,

characterized,

the marking area (1 12) has a toothed rim (1 18).

15. A method of measuring a torque and a rotational speed on a rotary shaft (32) comprising:

a) providing the rotary shaft (32) with a marking area (1 12) on which a non-rotationally symmetrical surface marking (36) is mounted and an axially spaced torque measuring range (106) without

Surface marking (36),

b) generating a magnetic field on the surface of the rotary shaft (32) and measuring magnetic field changes based on on the rotary shaft (32)

applied forces on the torque measuring range (106) by means of a

Torque magnetic field detecting device (52) and c) detecting the passage of the surface marking (36) upon rotation of the rotary shaft (32) by means of a surface mark detection device (1 10).

16. The method according to claim 15,

characterized,

in that step a) comprises: providing the surface marking (36) in such a way that it requires a surface shape deviating from a circular cylindrical shape and

in that step c) comprises: detecting the distance of the surface of the rotating shaft (32) from the surface mark detecting means (110).

17. The method according to claim 15 or 16,

characterized,

in that step b) comprises: generating a magnetic field both in the

Torque detection range (106) and in the adjacent

Marking area (1 12) by means of a common

Magnetic field generating device (50) and

18. The method according to any one of the preceding claims characterized by using a sensor head (48) according to any one of claims 1 to 10 and / or a sensor (S1) according to any one of claims 1 1 or 12 and / or a torque measuring arrangement (22) according to one of Claims 13 or 14.