ARRANGEMENT FOR MEASURING A FORCE OR A TORQUE, USING AT LEAST THREE MAGNETIC SENSORS

Abstract

The present invention relates to an arrangement for measuring a force and/or a torque (Mt) on a machine element extending along an axis, using the inverse magnetostrictive effect. The machine element has at least two magnetization areas for magnetization purposes, extending circumferentially around the axis. In addition, there are magnetically neutral areas, each area being arranged axially between the magnetization areas and/or axially next to the magnetization areas. The arrangement further includes at least one first magnetic sensor, a second magnetic sensor and a third magnetic sensor, each of which is designed to individually measure a direction component of a magnetic field caused by the magnetization and also by the force and/or torque (Mt) and each of which lies in a different axial position. According to the invention, the third magnetic sensor lies in an axial position of one of the magnetically neutral areas.

Claims

1. An arrangement for measuring at least one of a force or a torque (M.sub.t) on a machine element extending along an axis, comprising: at least first and second magnetization areas extending circumferentially about the axis of the machine element for a magnetization, magnetically neutral areas on the machine element each of which are arranged at least one of axially between the magnetization areas or axially next to the magnetization areas, at least one first magnetic field sensor, a second magnetic field sensor, and a third magnetic field sensor each of which are formed for individual measurement of one directional component of a magnetic field caused by the magnetization and also by the at least one of the force or the torque (M.sub.t) and are located at different axial positions, and the third magnetic field sensor is located at one axial position of one of the magnetically neutral areas.

2. The arrangement according to claim 1, wherein a directional component of the magnetic field caused by the magnetization and also by the at least one of the force or the torque (M.sub.t) is formed by an axial directional component, said directional component is measured by the magnetic field sensors, and the first magnetic field sensor is located at an axial position of the first magnetization area and the second magnetic field sensor is located at an axial position of the second magnetization area.

3. The arrangement according to claim 2, wherein the first magnetization area and the second magnetization area have an identical polarity, the magnetically neutral area at whose axial position the third magnetic field sensor is located is arranged axially between the first magnetization area and the second magnetization area, and the arrangement further comprises at least one fourth magnetic field sensor for individual measurement of an axial directional component of the magnetic field caused by the magnetization and also by the at least one of force or the torque (M.sub.t).

4. The arrangement according to claim 2, wherein the first magnetization area and the second magnetization area have opposite polarities, the magnetically neutral area at whose axial position the third magnetic field sensor is located is arranged axially next to the two magnetization areas, and the arrangement further comprises at least one fourth magnetic field sensor for individual measurement of an axial directional component of the magnetic field caused by the magnetization and also by the at least one of the force or by the torque (M.sub.t).

5. The arrangement according to claim 1, wherein the directional component of the magnetic field caused by the magnetization and also by the at least one of the force or the torque (M.sub.t) is formed by a radial directional component, said directional component is measured by the magnetic field sensors, the first magnetic field sensor is located at an axial position of one of the magnetically neutral areas, and the second magnetic field sensor is located at an axial position of one of the magnetically neutral areas.

6. The arrangement according to claim 5, wherein the first magnetization area and the second magnetization area have opposite polarities, the magnetically neutral area at whose axial position the third magnetic field sensor is located is arranged axially next to the two magnetization areas, and the arrangement further comprises at least one fourth magnetic field sensor for the individual measurement of a radial directional component of the magnetic field caused by the magnetization and also by the at least one of the force or by the torque (M.sub.t).

7. The arrangement according to claim 5, wherein the machine element further comprises a third magnetization area extending circumferentially about the axis for a magnetization, the first magnetization area and the third magnetization area have an identical polarity that is oriented opposite a polarity of the second magnetization area located axially in-between, the magnetically neutral area at whose axial position the third magnetic field sensor is located is arranged axially next to the three magnetization areas, and the arrangement further comprises at least one fourth magnetic field sensor for the individual measurement of a radial directional component of the magnetic field caused by the magnetization and also by the at least one of the force or the torque (M.sub.t).

8. The arrangement according to claim 1, wherein the magnetization areas are permanently magnetized, so that the magnetization is formed by a permanent magnetization.

9. The arrangement according to claim 1, wherein magnetization areas are formed in a ring shape about the axis.

10. The arrangement according to claim 1, wherein the magnetic field sensors have an identical distance to the axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0098] Additional details, advantages, and refinements of the invention are given in the following description of preferred embodiments of the invention with reference to the drawing. Shown are:

[0099] FIG. 1 a first embodiment of a first group of preferred embodiments of an arrangement according to the invention,

[0100] FIG. 2 a second embodiment of the first group of preferred embodiments of an arrangement according to the invention,

[0101] FIG. 3 a third embodiment of the first group of preferred embodiments of an arrangement according to the invention,

[0102] FIG. 4 a fourth embodiment of the first group of preferred embodiments of an arrangement according to the invention,

[0103] FIG. 5 a first embodiment of a second group of preferred embodiments of the arrangement according to the invention,

[0104] FIG. 6 a second embodiment of the second group of preferred embodiments of the arrangement according to the invention,

[0105] FIG. 7 a third embodiment of the second group of preferred embodiments of the arrangement according to the invention, and

[0106] FIG. 8 a fourth embodiment of the second group of preferred embodiments of the arrangement according to the invention,

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0107] FIG. 1 to FIG. 8 show an arrangement according to the invention, each figure in two views. The left part of each figure comprises a cross-sectional view, while the right part of each figure comprises a top view of the respective embodiment of the arrangement according to the invention.

[0108] FIG. 1 shows a first embodiment of a first group of preferred embodiments of the arrangement according to the invention. The arrangement first comprises a machine element in the form of a flange 01 that is mounted on a base body 02. A force or a torque, in particular, a torque M.sub.t, acts on the flange 01. The flange 01 has the shape of a hollow circular cylinder. The flange 01 extends along an axis 03 that also forms the center axis of the hollow cylindrical shape of the flange 01. The flange 01 is formed of a magneto-elastic material that has the magnetostrictive effect.

[0109] In an axial section of the flange 01, a first permanent magnetization area 04 is formed. In another axial section of the flange 01, a second permanent magnetization area 05 is formed. The permanent magnetization areas 04, 05 each extend circumferentially about the axis 03, i.e., they are circular permanent magnetizations. The polarity of the permanent magnetizations, i.e., their orientation, is identical in both permanent magnetization areas 04, 05. The two permanent magnetization areas 04, 05 are in two axially spaced apart planes.

[0110] This embodiment of the arrangement according to the invention further comprises a first magnetic field sensor 11, a second magnetic field sensor 12, a third magnetic field sensor 13, and a fourth magnetic field sensor 14. The magnetic field sensors 11, 12, 13, 14 are each formed for the individual measurement of an axial directional component of a magnetic field caused by the magnetizations of the permanent magnetization areas 04, 05 and also by the force and/or by the torque.

[0111] The four magnetic field sensors 11, 12, 13, 14 are arranged in three axially spaced apart planes. The first magnetic field sensor 11 is in the same plane as the first permanent magnetization area 04. The second magnetic field sensor 12 is in the same plane as the second permanent magnetization area 05. The third magnetic field sensor 13 and the fourth magnetic field sensor 14 are together in a plane between the two permanent magnetization areas 04, 05, where the flange 01 is not magnetized, i.e., is magnetically neutral. The first magnetic field sensor 11 and the third magnetic field sensor 13 are arranged with respect to the axis 03 opposite the second magnetic field sensor 12 and the fourth magnetic field sensor 14. The first magnetic field sensor 11 and the second magnetic field sensor 12 are each polarized opposite the third magnetic field sensor 13 and the fourth magnetic field sensor 14.

[0112] FIG. 2 shows a second embodiment of the first group of preferred embodiments of the arrangement according to the invention. This second embodiment differs merely in the number and arrangement of the magnetic field sensors from the embodiment shown in FIG. 1. This second embodiment further comprises a fifth magnetic field sensor 15, a sixth magnetic field sensor 16, a seventh magnetic field sensor 17, and an eighth magnetic field sensor 18. These additional magnetic field sensors 15, 16, 17, 18 are also each formed for the individual measurement of an axial directional component of the magnetic field caused by the magnetizations of the permanent magnetization areas 04, 05 and also by the force and/or by the torque.

[0113] The eight magnetic field sensors 11, 12, 13, 14, 15, 16, 17, 18 are arranged in three axially spaced apart planes. The first magnetic field sensor 11 and the fifth magnetic field sensor 15 are in the identical plane as the first permanent magnetization area 04. The second magnetic field sensor 12 and the sixth magnetic field sensor 16 are in the identical plane as the second permanent magnetization area 05. The third magnetic field sensor 13, the fourth magnetic field sensor 14, the seventh magnetic field sensor 17, and the eighth magnetic field sensor 18 are together in a plane between the two permanent magnetization areas 04, 05, where the flange 01 is not magnetized. The first magnetic field sensor 11, the second magnetic field sensor 12, the third magnetic field sensor 13, and the seventh magnetic field sensor 17 are arranged with respect to the axis 03 opposite the fourth magnetic field sensor 14, the fifth magnetic field sensor 15, the sixth magnetic field sensor 16, and the eighth magnetic field sensor 18. The first magnetic field sensor 11, the second magnetic field sensor 12, the fifth magnetic field sensor 15, and the sixth magnetic field sensor 11 are each polarized opposite the third magnetic field sensor 13, the fourth magnetic field sensor 14, the seventh magnetic field sensor 17, and the eighth magnetic field sensor 18. The third magnetic field sensor 13 and the seventh magnetic field sensor 17 are located essentially at the same position; for example, on a front and reverse side of a circuit board (not shown). The fourth magnetic field sensor 14 and the eighth magnetic field sensor 18 are located essentially at the same position; for example, on a front and a reverse side of a circuit board (not shown).

[0114] FIG. 3 shows a third embodiment of the first group of preferred embodiments of the arrangement according to the invention. This third embodiment differs merely in the polarity of the magnetization areas and in the arrangement of the magnetic field sensors from the embodiment shown in FIG. 1. In this third embodiment, the polarities of the permanent magnetizations in the two permanent magnetization areas 04, 05 are opposite each other, i.e., they have reverse orientation. The two permanent magnetization areas 04, 05 are in two axially spaced apart planes.

[0115] The four magnetic field sensors 11, 12, 13, 14 are arranged in three axially spaced apart planes. The first magnetic field sensor 11 is in the same plane as the first permanent magnetization area 04. The second magnetic field sensor 12 and the fourth magnetic field sensor 14 are together in the same plane as the second permanent magnetization area 05. The third magnetic field sensor 13 is in a plane axially next to the two permanent magnetization areas 04, 05, where the flange 01 is not magnetized. The first magnetic field sensor 11 and the second magnetic field sensor 12 are arranged with respect to the axis 03 opposite the third magnetic field sensor 13 and the fourth magnetic field sensor 14. The first magnetic field sensor 11 and the third magnetic field sensor 13 are each polarized opposite the second magnetic field sensor 12 and the fourth magnetic field sensor 14.

[0116] FIG. 4 shows a fourth embodiment of the first group of preferred embodiments of the arrangement according to the invention. This fourth embodiment differs merely in the polarity of the magnetization areas and in the arrangement of the magnetic field sensors from the embodiment shown in FIG. 2. In this fourth embodiment, the polarities of the permanent magnetizations in the two permanent magnetization areas 04, 05 are opposite each other, i.e., they have reverse orientation. The two permanent magnetization areas 04, 05 are in two axially spaced apart planes.

[0117] The eight magnetic field sensors 11, 12, 13, 14, 15, 16, 17, 18 are arranged in three axially spaced apart planes. The first magnetic field sensor 11 and the fifth magnetic field sensor 15 are in the same plane as the first permanent magnetization area 04. The second magnetic field sensor 12, the sixth magnetic field sensor 16, the seventh magnetic field sensor 17, and the eighth magnetic field sensor 18 are in the same plane as the second permanent magnetization area 05. The third magnetic field sensor 13 and the fourth magnetic field sensor 14 are together in a plane axially next to the two permanent magnetization areas 04, 05, where the flange 01 is not magnetized. The first magnetic field sensor 11, the second magnetic field sensor 12, the third magnetic field sensor 13, and the seventh magnetic field sensor 17 are arranged with respect to the axis 03 opposite the fourth magnetic field sensor 14, the fifth magnetic field sensor 15, the sixth magnetic field sensor 16, and the eighth magnetic field sensor 18. The first magnetic field sensor 11, the third magnetic field sensor 13, the fourth magnetic field sensor 14, and the fifth magnetic field sensor 15 are each polarized opposite the second magnetic field sensor 12, the sixth magnetic field sensor 16, the seventh magnetic field sensor 17, and the eighth magnetic field sensor 18. The second magnetic field sensor 12 and the seventh magnetic field sensor 17 are located essentially at the same position; for example, on a front and reverse side of a circuit board (not shown). The sixth magnetic field sensor 16 and the eighth magnetic field sensor 18 are located essentially at the same position; for example, on a front and a reverse side of a circuit board (not shown).

[0118] FIG. 5 shows a first embodiment of a second group of preferred embodiments of the arrangement according to the invention. The arrangement first comprises a machine element in the form of a flange 01 that is mounted on a base body 02. A force or a torque, in particular, a torque M.sub.t, acts on the flange 01. The flange 01 has the shape of a hollow circular cylinder. The flange 01 extends along an axis 03 that also forms the center axis of the hollow cylindrical shape of the flange 01. The flange 01 consists of a magneto-elastic material that has the magnetostrictive effect.

[0119] In an axial section of the flange 01, a first permanent magnetization area 04 is formed. In another axial section of the flange 01, a second permanent magnetization area 05 is formed. The permanent magnetization areas 04, 05 extend circumferentially about the axis 03, i.e., they are circular permanent magnetizations. The polarity of the permanent magnetizations in the two permanent magnetization areas 04, 05 are opposite each other, i.e., they have reverse orientation. The two permanent magnetization areas 04, 05 are in two axially spaced apart planes.

[0120] This embodiment of the arrangement according to the invention further comprises a first magnetic field sensor 11, a second magnetic field sensor 12, a third magnetic field sensor 13, and a fourth magnetic field sensor 14. The magnetic field sensors 11, 12, 13, 14 are each formed for the individual measurement of a radial directional component of a magnetic field caused by the magnetizations of the permanent magnetization areas 04, 05 and also by the force and/or by the torque.

[0121] The four magnetic field sensors 11, 12, 13, 14 are arranged in three axially spaced apart planes, wherein none of the four magnetic field sensors 11, 12, 13, 14 are together in a plane with one of the permanent magnetization areas 04, 05. Instead, the magnetic field sensors 11, 12, 13, 14 are arranged in axial positions at which the flange 01 is magnetically neutral. The first magnetic field sensor 11 is in a plane axially next to the two permanent magnetization areas 04, 05, wherein the flange 01 is not magnetized, i.e., is magnetically neutral. At the opposite axial end, the third magnetic field sensor 13 is in a plane axially next to the two permanent magnetization areas 04, 05, where the flange 01 is not magnetized. The second magnetic field sensor 12 and the fourth magnetic field sensor 14 are together in a plane axially between the permanent magnetization areas 04, 05, where the flange 01 is not magnetized. The first magnetic field sensor 11 and the second magnetic field sensor 12 are arranged with respect to the axis 03 opposite the third magnetic field sensor 13 and the fourth magnetic field sensor 14. The first magnetic field sensor 11 and the fourth magnetic field sensor 14 are each polarized opposite the second magnetic field sensor 12 and the third magnetic field sensor 13.

[0122] FIG. 6 shows a second embodiment of the second group of preferred embodiments of the arrangement according to the invention. This second embodiment differs merely in the number and arrangement of the magnetic field sensors from the embodiment shown in FIG. 5. This second embodiment further comprises a fifth magnetic field sensor 15, a sixth magnetic field sensor 16, a seventh magnetic field sensor 17, and an eighth magnetic field sensor 18. These additional magnetic field sensors 15, 16, 17, 18 are also each formed for the individual measurement of a radial directional component of a magnetic field caused by the magnetizations of the permanent magnetization areas 04, 05 and also by the force and/or by the torque.

[0123] The eight magnetic field sensors 11, 12, 13, 14, 15, 16, 17, 18 are arranged in three axially spaced apart planes, wherein none of the eight magnetic field sensors 11, 12, 13, 14, 15, 16, 17, 18 are together in a plane with one of the permanent magnetization areas 04, 05. Instead, the magnetic field sensors 11, 12, 13, 14, 15, 16, 17, 18 are arranged in axial positions at which the flange 01 is magnetically neutral. The first magnetic field sensor 11 and the fifth magnetic field sensor 15 are in a plane axially next to the two permanent magnetization areas 04, 05, where the flange 01 is not magnetized. At the opposite axial end, the third magnetic field sensor 13 and the fourth magnetic field sensor 14 are in a plane axially next to the two permanent magnetization areas 04, 05, where the flange 01 is not magnetized. The second magnetic field sensor 12, the sixth magnetic field sensor 16, the seventh magnetic field sensor 17, and the eighth magnetic field sensor 18 are together in a plane between the two permanent magnetization areas 04, 05, where the flange 01 is not magnetized. The first magnetic field sensor 11, the second magnetic field sensor 12, the third magnetic field sensor 13, and the seventh magnetic field sensor 17 are arranged with respect to the axis 03 opposite the fourth magnetic field sensor 14, the fifth magnetic field sensor 15, the sixth magnetic field sensor 16, and the eighth magnetic field sensor 18. The first magnetic field sensor 11, the third magnetic field sensor 13, the sixth magnetic field sensor 16, and the eighth magnetic field sensor 18 are each polarized opposite the second magnetic field sensor 12, the fourth magnetic field sensor 14, the fifth magnetic field sensor 15, and the seventh magnetic field sensor 17. The second magnetic field sensor 12 and the seventh magnetic field sensor 17 are located essentially at the same position; for example, on a front and a reverse side of a circuit board (not shown). The sixth magnetic field sensor 16 and the eighth magnetic field sensor 18 are located essentially at the same position; for example, on a front and a reverse side of a circuit board (not shown).

[0124] FIG. 7 shows a third embodiment of the second group of preferred embodiments of the arrangement according to the invention. This third embodiment differs merely in the number and polarity of the magnetization areas and in the arrangement of the magnetic field sensors from the embodiment shown in FIG. 5. This third embodiment has a third magnetization area 06, wherein the polarity of the permanent magnetization of the axially center, second permanent magnetization area 05 is oriented opposite the polarities of the permanent magnetizations of the two axially outer permanent magnetization areas 04, 06, i.e., the first permanent magnetization area 04 and the third permanent magnetization area 06, i.e., they have a reverse orientation. The three permanent magnetization areas 04, 05, 06 are in three axially spaced apart planes.

[0125] The four magnetic field sensors 11, 12, 13, 14 are arranged in three axially spaced apart planes, wherein none of the four magnetic field sensors 11, 12, 13, 14 are together in a plane with one of the permanent magnetization areas 04, 05, 06. Instead, the magnetic field sensors 11, 12, 13, 14 are arranged in axial positions at which the flange 01 is magnetically neutral. The first magnetic field sensor 11 is in a plane axially next to the three permanent magnetization areas 04, 05, 06, where the flange 01 is not magnetized. At the opposite axial end, the third magnetic field sensor 13 is in a plane axially next to the three permanent magnetization areas 04, 05, 06, where the flange 01 is not magnetized. The second magnetic field sensor 12 is in a plane axially between the axially outer first permanent magnetization area 04 and the axially center, second permanent magnetization areas 05, where the flange 01 is not magnetized. The fourth magnetic field sensor 14 is in a plane between the axially outer third permanent magnetization area 06 and the axially center, second permanent magnetization area 05, where the flange 01 is not magnetized. The first magnetic field sensor 11 and the second magnetic field sensor 12 are arranged with respect to the axis 03 opposite the third magnetic field sensor 13 and the fourth magnetic field sensor 14. The first magnetic field sensor 11 and the third magnetic field sensor 13 are each polarized opposite the second magnetic field sensor 12 and the fourth magnetic field sensor 14.

[0126] FIG. 8 shows a fourth embodiment of the second group of preferred embodiments of the arrangement according to the invention. This fourth embodiment differs merely in the number and polarity of the magnetization areas and in the arrangement of the magnetic field sensors from the embodiment shown in FIG. 6. This third embodiment has a third magnetization area 06, wherein the polarity of the permanent magnetization of the axially center, second permanent magnetization area 05 is oriented opposite the polarities of the permanent magnetizations of the two axially outer permanent magnetization areas 04, 06, i.e., of the first permanent magnetization area 04 and the second permanent magnetization area 06, i.e., they have a reverse orientation. The three permanent magnetization areas 04, 05, 06 are in three axially spaced apart planes.

[0127] The eight magnetic field sensors 11, 12, 13, 14, 15, 16, 17, 18 are arranged in three axially spaced apart planes, wherein none of the eight magnetic field sensors 11, 12, 13, 14, 15, 16, 17, 18 are together in a plane with one of the permanent magnetization areas 04, 05, 06. Instead, the magnetic field sensors 11, 12, 13, 14, 15, 16, 17, 18 are arranged in axial positions at which the flange 01 is magnetically neutral. The first magnetic field sensor 11 and the fifth magnetic field sensor 15 are together in a plane axially next to the three permanent magnetization areas 04, 05, 06, where the flange 01 is not magnetized. At the opposite axial end, the third magnetic field sensor 13 and the fourth magnetic field sensor 14 are in a plane axially next to the three permanent magnetization areas 04, 05, 06, where the flange 01 is not magnetized. The second magnetic field sensor 12 and the sixth magnetic field sensor 16 are together in a plane between the axially outer first permanent magnetization area 04 and the axially center, second permanent magnetization area 05, where the flange 01 is not magnetized. The seventh magnetic field sensor 17 and the eighth magnetic field sensor 18 are together in a plane between the axially outer third permanent magnetization area 06 and the axially center, second permanent magnetization area 05, where the flange 01 is not magnetized. The first magnetic field sensor 11, the second magnetic field sensor 12, the third magnetic field sensor 13, and the seventh magnetic field sensor 17 are arranged with respect to the axis 03 opposite the fourth magnetic field sensor 14, the fifth magnetic field sensor 15, the sixth magnetic field sensor 16, and the eighth magnetic field sensor 18. The first magnetic field sensor 11, the fourth magnetic field sensor 14, the sixth magnetic field sensor 16, and the seventh magnetic field sensor 17 are each polarized opposite the second magnetic field sensor 12, the third magnetic field sensor 13, the fifth magnetic field sensor 15, and the eighth magnetic field sensor 18.

LIST OF REFERENCE NUMBERS

[0128] 01 Flange [0129] 02 Base body [0130] 03 Axis [0131] 04 First permanent magnetization area [0132] 05 Second permanent magnetization area [0133] 06 Third permanent magnetization area [0134] 07 [0135] 08 [0136] 09 [0137] 11 First magnetic field sensor [0138] 12 Second magnetic field sensor [0139] 13 Third magnetic field sensor [0140] 14 Fourth magnetic field sensor [0141] 15 Fifth magnetic field sensor [0142] 16 Sixth magnetic field sensor [0143] 17 Seventh magnetic field sensor [0144] 18 Eighth magnetic field sensor