Torque transmitter and torque sensor, manufacturing method and measuring method

Abstract

In order to inexpensively measure torque on a shaft such that the measurement is as independent as possible from distance changes or material inconsistencies of the shaft around the circumference thereof, the invention provides a torque transmitter for a torque sensor for measuring a torque on a shaft, having a carrier plate that has a plurality of sensor element carrier plate regions, on each of which at least one sensor element for recording magnetic field changes, caused by the magnetoelastic effect, is arranged, and at least one enclosure region that is designed to at least partly enclose the shaft around the circumference of the shaft, wherein at least one flexible connection region is provided by way of which at least one of the sensor element carrier plate regions is able to be pivoted relative to another sensor element carrier plate region or relative to the at least one enclosure region.

Claims

1. A torque transmitter for a torque sensor for measuring a torque on a shaft, having a carrier plate that has a plurality of sensor element carrier plate regions, on each of which at least one sensor element for recording magnetic field changes is arranged, and at least one enclosure region that is designed to at least partly enclose the shaft around the circumference of the shaft, wherein at least one flexible connection region is provided by way of which at least one of the sensor element carrier plate regions is able to be pivoted relative to another sensor element carrier plate region or relative to the at least one enclosure region.

2. The torque transmitter as claimed in claim 1, characterized in that the enclosure region is formed at least partly by a plurality of the sensor element carrier plate regions, wherein at least one flexible connection region is arranged between adjacent sensor element carrier plate regions.

3. The torque transmitter as claimed in claim 1, characterized in that the enclosure region has an annular design, wherein a plurality of sensor element carrier plate regions are arranged radially within the enclosure region spaced apart in the circumferential direction, protrude inwardly and are able to be bent outward in the axial direction by way of the flexible connection region.

4. The torque transmitter as claimed in claim 1, characterized in that each of the sensor elements has at least one magnetic field generation apparatus for generating a magnetic field in the shaft and one magnetic field recording apparatus for recording a change of the magnetic field caused by a torque acting on the shaft.

5. The torque transmitter as claimed in claim 4, characterized in that the magnetic field generation apparatus has at least one generator coil and the magnetic field recording apparatus has at least one measurement coil, wherein at least one, a plurality of or all of these coils are formed as planar coils on the carrier plate.

6. The torque transmitter as claimed in claim 4, characterized a) in that generator coils of the magnetic field generation apparatuses of at least two adjacent sensor elements are connected alternately or in parallel and/or b) in that a plurality of measurement coils of the magnetic field recording apparatus of a sensor element are connected alternately or in parallel and/or c) in that mutually corresponding measurement coils of the magnetic field recording apparatuses of at least two adjacent sensor elements are connected alternately or in parallel.

7. The torque transmitter as claimed in claim 1, characterized in that the carrier plate is formed by at least one substrate on which the sensor elements are formed, or by at least one circuit board.

8. A torque sensor, comprising a sleeve having a through-aperture for passing through a shaft and a torque transmitter as claimed in claim 1 that is arranged in or on the sleeve around the through-aperture.

9. A torque measurement arrangement for measuring the torque on a shaft, comprising the shaft and a torque transmitter as claimed in claim 1, which at least partly surrounds the shaft.

10. A method for manufacturing a torque transmitter, comprising: a) providing a carrier plate b) populating a plurality of regions of the carrier plate with sensor elements for recording magnetic field changes caused by torques acting on a shaft, c) providing at least one flexible connection region between the regions that are populated or to be populated with sensor elements such that at least one enclosure region of the carrier plate is at least partly able to enclose a shaft, with the flexible connection region bending.

11. The method as claimed in claim 10, characterized in that step b) comprises: manufacturing planar coils on the plurality of regions.

12. The method as claimed in claim 10, characterized by a) singulating the regions of the carrier plate that are populated or to be populated with sensor elements, wherein step c) comprises connecting the singulated regions by way of the flexible connection regions, or b) providing the carrier plate such that the regions that are populated or to be populated with sensor elements are connected flexibly to one another, or c) providing a flexible carrier plate, or d) providing the flexible connection regions through material machining on the carrier plate.

13. A method for manufacturing a torque sensor, comprising performing the manufacturing method as claimed in claim 10 in order to manufacture a torque transmitter and embedding the torque transmitter in a sleeve having a through-aperture for attachment to a shaft to be measured.

14. A torque measurement system for measuring a torque on a shaft, comprising: the torque transmitter as claimed in claim 1 arranged at least partly around the shaft, wherein the torque is recorded by way of the plurality of sensor elements on regions of the shaft that are spaced apart or distributed in the circumferential direction.

15. The torque measurement system as claimed in claim 14, characterized in that sensor elements have at least two pairs of measurement coils (A1, A2; B1, B2), wherein each pair of measurement coils each measures a magnetic field circuit and the magnetic field circuit of the first pair (A1, A2) is arranged at an angle of 5° to 175°, preferably 20° to 160°, to the magnetic field circuit of the second pair (B1, B2), wherein a measured signal is formed from one or more of the signals of the group of signals that the sum (A) of the signals from the first pair of measurement coils (A1+A2), the sum (B) of the signals from the second pair of measurement coils (B1+B2) and the difference (A−B=(A1+B1)−(B1+B2)) between the sum of the measured signals of the first pair of measurement coils (A1+A2) and the sum of the measured signals of the second pair of measurement coils (B1+B2).

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Exemplary embodiments of the invention are explained in more detail below with reference to the attached drawings. In the figures:

(2) FIG. 1 shows a first exemplary embodiment of a torque transmitter for forming a torque sensor, by way of which torque on a shaft is able to be recorded by recording magnetic field changes caused by the magnetoelastic effect;

(3) FIG. 2 shows an intermediate step for manufacturing a torque sensor from the torque transmitter from FIG. 1;

(4) FIG. 3 shows a torque measurement arrangement having a torque sensor that is formed with the torque transmitter from FIG. 1, and a shaft to be measured;

(5) FIG. 4 shows a further exemplary embodiment of a torque transmitter;

(6) FIG. 5 shows yet another embodiment of a torque transmitter;

(7) FIG. 6 shows a torque measurement arrangement for measuring a torque on a shaft, comprising the shaft and a torque transmitter according to the embodiment from FIG. 4 arranged around the shaft; and

(8) FIG. 7 shows a plan view of a comparable torque measurement arrangement that applies another embodiment of a torque transmitter.

DETAILED DESCRIPTION OF THE INVENTION

(9) The figures illustrate various embodiments of torque transmitters 10 that are able to be used in a torque sensor 12. The torque transmitters 10 are used to measure a torque on a shaft 14. For this purpose, the torque transmitter 10 is designed such that it is able to be arranged around the shaft 14. The arrangement is such that the torque transmitter 10 at least partly, preferably mostly, and more preferably completely, encloses the shaft 14.

(10) For this purpose, the torque transmitter 10 has an enclosure region 16. The torque transmitter 10 furthermore has a plurality of sensor elements that each have a magnetic field generation apparatus 20 and a magnetic field recording apparatus 22.

(11) The magnetic field generation apparatus 20 serves to generate a magnetic field in and in particular on the surface of the shaft 14. The magnetic field recording apparatus 22 is designed to record changes of the magnetic field caused by a torque acting on the shaft 14 caused by the magnetoelastic effect. For more details on possible designs and geometries and on the physical principles, reference is made to documents D1 to D4 mentioned at the outset.

(12) At least one of the apparatuses 20, 22 has at least one coil that is formed as a planar coil 24.

(13) In particularly preferred configurations, the magnetic field generation apparatus 20 has at least one generator coil 26.

(14) In particularly preferred configurations, the magnetic field recording apparatus 22 has at least one measurement coil 28. An arrangement of measurement coils 28 that has a first measurement coil A1 and a second measurement coil B1 is preferably provided.

(15) In particularly preferred configurations, a pair of first measurement coils A1, A2 and a pair of second measurement coils B1, B2 is provided. Both the generator coil 26 and each of the measurement coils 28 are preferably formed as planar coils.

(16) Each of the coils 26, 28 furthermore encloses a magnetic flux concentrator 32 preferably having a ferrite core 30.

(17) All of the sensor elements 18 are preferably manufactured on a—preferably multipart—carrier plate 34. The carrier plate may have a substrate to which the planar coils 24 and the ferrite core 30 have been applied using semiconductor technology methods.

(18) Particularly preferably, the carrier plate 34 has at least one circuit board 36 (PCB), wherein the planar coils 24 are formed on one or more conductor layers of the circuit board 36 and wherein the ferrite core 30 of the individual magnetic flux concentrators 32 is provided in addition, as has been disclosed and explained in detail in DE 10 2016 122 172.4.

(19) The carrier plate 34 may be constructed from a plurality of individual elements. Manufacturing on a carrier plate may also take place, wherein the carrier plate 34 is then divided into a plurality of individual regions through material machining.

(20) A plurality of sensor element carrier plate regions 38 are in particular formed, wherein a sensor element 18 having the corresponding coils 24, 26, 28 and the corresponding magnetic flux concentrator 32 is arranged on each of these sensor element carrier plate regions 38.

(21) A flexible connection region 40 is furthermore provided, by way of which individual regions of the carrier plate 34 are connected to one another in a manner able to be pivoted or bent relative to one another in terms of position, wherein a wired electrical connection is provided at the same time in order to connect the coils 24, 26, 28 to driver and evaluation electronics 42. The components of the driver and evaluation electronics 42 may also be formed on a corresponding region of the carrier plate 34 (electronics carrier plate region 44).

(22) FIGS. 1 to 3 illustrate a first embodiment of the torque transmitter 10, in which a plurality of sensor element carrier plate regions 38 are connected to one another with a flexible connection region 40 between them. In the illustrated embodiment, four sensor element carrier plate regions and therefore four sensor elements 18 are provided. In other configurations, three or five or even more sensor element carrier plate regions 38 having a corresponding number of sensor elements 18 are provided.

(23) The sensor element carrier plate regions 38 may be pivoted toward one another by way of the flexible connection region 40 and thus be placed around the shaft 14.

(24) In one preferred configuration for manufacturing such a torque transmitter 10 according to the first embodiment, the sensor elements 18 are manufactured on the carrier plate 34 and then the flexible connection regions 40 are manufactured by way of material removal such that conductor tracks for the connection between coils 26, 28 and the driver and evaluation electronics 42 remain but the flexible connection region 40 is able to be bent relative to the sensor element carrier plate regions 38.

(25) One embodiment for manufacturing a torque sensor 12 using the torque transmitter 10 of the first embodiment is explained in more detail below with reference to the illustration in FIGS. 2 and 3. FIG. 2 illustrates a carrier sleeve 46 that may be made for example from plastic and has attachment elements for—for example temporarily—holding the sensor element carrier plate regions 38.

(26) In this configuration of the torque transmitter, the enclosure region 16 is formed by the individual sensor element carrier plate regions 38 with the flexible connection regions 40 between them. This is guided around the carrier sleeve 46, wherein the sensor element carrier plate regions 38 are fixed to the carrier sleeve 46 by way of the attachment elements—for example retaining clips 48.

(27) This structure of FIG. 2 may then be inserted into an injection molding machine and be injection-molded with plastic around the outside in order thereby to produce a sleeve 50 in which the torque transmitter 10 is arranged around a through-aperture 52 of the sleeve. The individual elements of the torque transmitter 10 are thus embedded and packed in plastic. It is possible to pass the shaft 14 to be measured through the interior of the through-aperture 52, giving the torque measurement arrangement 54 shown in FIG. 3.

(28) In one configuration, the carrier sleeve 46 remains present as further protection; in another configuration, the carrier sleeve 46 is removed following the injection-molding with the sleeve 50.

(29) FIG. 3 shows the torque measurement arrangement 54 having the shaft 14 and the torque sensor 12 formed by the sleeve 50 and the torque transmitter 10.

(30) In this case, the sensor elements 18 preferably each lie diametrically opposite one another in pairs.

(31) By arranging individual sensor elements around the shaft 14 to be measured, it is possible to compensate dependencies of the torque measured signal on distance changes and variations in the sensor signal caused by other effects during rotation of the shaft (RSN), giving a measured signal that is as independent as possible from tolerances in the mounting of the shaft and its circumference and as independent as possible from material inconsistencies around the circumference of the shaft.

(32) The connection of the individual coils of the sensor elements 18 may in this case be selected in various ways. In one configuration, manufacturing takes place such that the generator coils 26 are selectively connected in the same way as or alternately to one another, in series or in parallel, to an AC current source (not illustrated, for example implemented in the electronics on the electronics carrier plate region 44). In an alternative connection, the generator coils 26 are able to be driven individually or differently connected in groups.

(33) The connection of the measurement coils 28 of the sensor elements 18 may also be different. A connection is preferably made such that both the sum of the signals of the first pairs A1+A2, sensitive in a first direction, of the measurement coils and the sum of the signals of the second pair (B1+B2), sensitive in a second direction, are able to be measured directly and the difference between these sums is able to be measured.

(34) FIG. 4 illustrates a further exemplary embodiment of the torque transmitter 10 that is suitable for smaller shaft diameters.

(35) The enclosure region 16 here is not formed by sensor element carrier plate regions 38 that are connected to one another, but rather by a dedicated annular region 56 of the carrier plate 34, wherein sensor element carrier plate regions 38 are braced inwardly at an inner region. A flexible connection region 40 is provided in each case between the sensor element carrier plate regions 38 and the annular region 56, such that the sensor element carrier plate regions 38 are able to be folded out axially from the plane of the drawing in FIG. 4. Intended breaking points may for example be provided for this purpose between the individual sensor element carrier plate regions 38.

(36) As illustrated in FIG. 6, the shaft 14 is able to be passed through the interior of the annular region 56, such that the sensor element carrier plate regions 38 on the flexible connection regions 40 pivot away in an axial direction and bear on the shaft 14 distributed around the circumference of the shaft 14.

(37) In the illustration from FIG. 4, a generator coil 26 and a first measurement coil A1 and a second measurement coil B1 are provided, such that three planar coils 24 are provided per sensor element 18, wherein the ferrite cores 30, which are provided between the generator coil 26 and each of the measurement coils A1, B1, enclose an angle between them of between 90° and 0°, and in particular between 55° and 35°.

(38) FIG. 5 illustrates yet another embodiment for very small shaft diameters. This configuration corresponds in terms of basic structure to the configuration from FIG. 4, with an annular region 56 and inwardly protruding sensor element carrier plate regions 38. In this case, only two sensor elements 18 are provided, wherein the magnetic field generation apparatus 20 has a permanent magnet and direction changes of magnetic field lines are recorded by way of the magnetic field recording apparatus 22.

(39) FIG. 7 shows the arrangement of the annular region 56 of a further configuration of the torque transmitter 10 that corresponds in terms of basic structure to the structure of FIGS. 4 and 5, wherein an even greater number of sensor elements 18 is further provided around the shaft 14.

LIST OF REFERENCE SIGNS

(40) 10 Torque transmitter

(41) 12 Torque sensor

(42) 14 Shaft

(43) 16 Enclosure region

(44) 18 Sensor element

(45) 20 Magnetic field generation apparatus

(46) 22 Magnetic field recording apparatus

(47) 24 Planar coil

(48) 26 Generator coil

(49) 28 Measurement coil

(50) A1 First measurement coil

(51) B1 Second measurement coil

(52) A2 First measurement coil

(53) B2 Second measurement coil

(54) 30 Ferrite core

(55) 32 Magnetic flux concentrator

(56) 34 Carrier plate

(57) 36 Circuit board

(58) 38 Sensor element carrier plate region

(59) 40 Flexible connection region

(60) 42 Driver and evaluation electronics

(61) 44 Electronics carrier plate region

(62) 46 Carrier sleeve

(63) 48 Retaining clips

(64) 50 Sleeve

(65) 52 Through-aperture

(66) 54 Torque measurement arrangement

(67) 56 Annular region