Abstract
The present invention relates to an arrangement for measuring a force and/or a torque on a machine element extending in an axis, using the inverse magnetostrictive effect. The machine element has at least one permanent magnetization. The permanent magnetization extends along a closed magnetization path. The magnetization path runs preferably at least partially along the surface of the machine element. The arrangement further includes at least one magnetic field sensor which is arranged opposite the machine element. The magnetic field sensor serves to determine a magnetic field and is designed to measure at least one vector component of a magnetic field coming from the machine element, which field is produced on the one hand by the permanent magnetization and on the other hand by the force and/or by the torque. According to the invention, the orientation of the permanent magnetization relative to the axis changes along the magnetization path.
Claims
1. An arrangement for measuring at least one of a force or a torque on a machine element extending along an axis, the arrangement comprising the machine element having a permanent magnetization that extends along a closed magnetization path, at least one magnetic field sensor constructed for measuring at least one component of a magnetic field generated by the permanent magnetization and by the at least one of the force or the torque, wherein an alignment of the permanent magnetization relative to the axis changes along the magnetization path, and the axis of the machine element is arranged outside of the closed magnetization path.
2. The arrangement according to claim 1, wherein the permanent magnetization is magnetically neutral outside of the machine element in a state of the machine element unloaded by the at least one of the force or by the torque.
3. The arrangement according to claim 1, wherein the permanent magnetization is formed by a magnetized, three-dimensional partial area of the machine element that has a closed cord form, and the closed magnetization path represents a center axis of the cord.
4. The arrangement according to claim 1, wherein the closed magnetization path is formed by a three-dimensional curve that is closed in sp ace.
5. The arrangement according to claim 1, wherein the closed magnetization path has a parallelogram shape or a superellipse shape, and the parallelogram shape or the superellipse shape is projected onto the surface of the machine element.
6. The arrangement according to claim 5, wherein sides of the parallelogram shape or axes of the superellipse shape are inclined relative to the axis of the machine element.
7. The arrangement according to claim 1, wherein the closed magnetization path extends in a plane, and a perpendicular from a center point of a surface spanned by the closed magnetization path lies on the axis in the plane.
8. The arrangement according to claim 7, wherein the closed magnetization path has two longitudinal sides, and one of the two longitudinal sides runs on the surface of the machine element and the other of the two longitudinal sides runs below the surface of the machine element.
9. The arrangement according to claim 1, wherein the machine element has multiple permanent magnetizations.
10. The arrangement according to claim 9, wherein the multiple permanent magnetizations have identical constructions and are oriented in a same way relative to the axis of the machine element.
11. An arrangement for measuring at least one of a force or a torque on a machine element extending along an axis, the arrangement comprising the machine element having a permanent magnetization that extends along a closed magnetization path, at least one magnetic field sensor constructed for measuring at least one component of a magnetic field generated by the permanent magnetization and by the at least one of the force or the torque, wherein an alignment of the permanent magnetization relative to the axis changes along the magnetization path, the closed magnetization path is formed by a three-dimensional curve that is closed in space, and the axis of the machine element is arranged outside of the closed magnetization path.
12. The arrangement according to claim 11, wherein machine element is a circular cylinder.
13. The arrangement according to claim 11, wherein the permanent magnetization is formed by a magnetized, three-dimensional partial area of the machine element that has a closed cord form, and the closed magnetization path represents a center axis of the cord.
14. The arrangement according to claim 11, wherein the closed magnetization path is formed by a three-dimensional curve that is closed in space.
15. The arrangement according to claim 11, wherein the closed magnetization path has a parallelogram shape or a superellipse shape, and the parallelogram shape or the superellipse shape is projected onto the surface of the machine element.
16. The arrangement according to claim 15, wherein sides of the parallelogram shape or axes of the superellipse shape are inclined relative to the axis of the machine element.
17. The arrangement according to claim 11, wherein the closed magnetization path extends in a plane, and a perpendicular from a center point of a surface spanned by the closed magnetization path lies on the axis in the plane.
18. The arrangement according to claim 17, wherein the closed magnetization path has two longitudinal sides, and one of the two longitudinal sides runs on the surface of the machine element and the other of the two longitudinal sides runs below the surface of the machine element.
19. The arrangement according to claim 1, wherein the machine element has multiple permanent magnetizations.
20. The arrangement according to claim 19, wherein the multiple permanent magnetizations have identical constructions and are oriented in a same way relative to the axis of the machine element.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Other advantages, details, and refinements of the invention are produced from the following description of preferred embodiments with reference to the drawing. Shown are:
(2) FIG. 1: a machine element of a preferred embodiment of the arrangement according to the invention in a cross-sectional view,
(3) FIG. 2: a magnetization path of an arrangement according to the invention,
(4) FIG. 3: a magnetization path of a first preferred embodiment of the arrangement according to the invention,
(5) FIG. 4: a magnetization path of a second preferred embodiment of the arrangement according to the invention,
(6) FIG. 5: a magnetization path of a third preferred embodiment of the arrangement according to the invention,
(7) FIG. 6: a magnetization path of a fourth preferred embodiment of the arrangement according to the invention,
(8) FIG. 7: a magnetization path of a fifth preferred embodiment of the arrangement according to the invention,
(9) FIG. 8: magnetization paths of a sixth preferred embodiment of the arrangement according to the invention,
(10) FIG. 9: magnetization paths of a seventh preferred embodiment of the arrangement according to the invention,
(11) FIG. 10: magnetization paths of an eighth preferred embodiment of the arrangement according to the invention,
(12) FIG. 11: magnetization paths of a ninth preferred embodiment of the arrangement according to the invention,
(13) FIG. 12: one of the magnetization paths shown in FIG. 8 in another view, and
(14) FIG. 13: one of the magnetization paths shown in FIG. 8 in another view.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(15) FIG. 1 shows a machine element of a preferred embodiment of the arrangement according to the invention in a cross-sectional view. This machine element involves a hollow shaft made from a magnetostrictive material. The hollow shaft can be exposed to different forces and torques, which are to be measured with the help of the arrangement according to the invention. The arrangement according to the invention further comprises a magnetic field sensor (not shown) that is arranged at a distance to the hollow shaft in the vicinity of the hollow shaft.
(16) The hollow shaft is partially magnetized by a permanent magnetization. The permanent magnetization is formed along a magnetization path 01 (shown in FIG. 2 to FIG. 13).
(17) In FIG. 1, an angle is shown. FIG. 2 to FIG. 13 include representations of the hollow shaft with reference to the angle . FIG. 2 to FIG. 11 show a cylindrical lateral-face-shaped surface 02 of different embodiments of the hollow shaft, wherein the cylindrical lateral-face-shaped surface 02 is represented by an unrolling of the hollow shaft over the angle . Accordingly, the cylindrical lateral-face-shaped surface 02 of the hollow shaft is shown as a rectangle.
(18) FIG. 2 shows a magnetization path 01 of an arrangement according to the invention. The magnetization path runs on a cylindrical lateral-face-shaped surface 02 of the hollow shaft. The magnetization path 01 is closed and has, in the shown general embodiment, an irregular shape. Because the magnetization path 01 is arranged on the cylindrical lateral-face-shaped surface 02 of the hollow shaft and is closed, it has different orientations relative to an axis of the hollow shaft along its profile.
(19) FIG. 3 shows a magnetization path 01 of a first preferred embodiment of the arrangement according to the invention. In the unrolled representation, the magnetization path has the shape of a square. The square is inclined by 45 relative to the axis of the hollow shaft. This inclination angle , however, could also have a different magnitude. The edge lengths a and b can also have a different size, so that the magnetization path has, in the unrolled representation, the shape of a rectangle.
(20) FIG. 4 shows a magnetization path 01 of a second preferred embodiment of the arrangement according to the invention. In the unrolled representation, the magnetization path has the shape of a square. The square is oriented parallel to the axis of the hollow shaft. The square, however, could also be inclined by an inclination angle relative to the axis. The edge lengths a and b could also have different magnitudes, so that the magnetization path 01 has, in the unrolled representation, the shape of a rectangle.
(21) FIG. 5 shows a magnetization path 01 of a third preferred embodiment of the arrangement according to the invention. In the unrolled representation, the magnetization path 01 has the shape of a circle. The magnetization could also be oriented differently.
(22) FIG. 6 shows a magnetization path 01 of a fourth preferred embodiment of the arrangement according to the invention. In the unrolled representation, the magnetization path 01 has the shape of a superellipse-like oval. The magnetization could also be oriented differently. The radii r.sub.1 and r.sub.2 can have different magnitudes and are variable. The edge length b is also variable.
(23) FIG. 7 shows a magnetization path 01 of a fifth preferred embodiment of the arrangement according to the invention. In the unrolled representation, the magnetization path 01 has the shape of a superellipse-like oval. The magnetization can be oriented differently. The radii r.sub.1 can have different magnitudes and are variable. The edge length a is also variable.
(24) FIG. 8 to FIG. 13 show magnetization paths 01 of preferred embodiments of the arrangement according to the invention, wherein the magnetization paths 01 are arranged not completely on the cylindrical lateral-face-shaped surface 02 of the hollow shaft. Therefore, FIG. 8 to FIG. 11 each show only a portion of each magnetization path 01, namely the part that is arranged on the cylindrical lateral-face-shaped surface 02 of the hollow shaft. This part has, in the shown embodiments in the unrolled representation, the shape of a straight section.
(25) The embodiments shown in FIG. 8 to FIG. 13 each have two of the permanent magnetizations, wherein the two permanent magnetizations stand symbolically for multiple permanent magnetizations.
(26) The magnetization paths 01 of the embodiments shown in FIG. 8 to FIG. 13 are each in a plane and have the shape of a superellipse-like oval. The ovals have a narrow construction, so that they each have two longitudinal sides. One of the two longitudinal sides runs on the surface 02 of the hollow shaft. The other of the two longitudinal sides runs under the longitudinal side located on the surface 02 in the interior of the material of the hollow shaft offset in the direction of the axis of the hollow shaft. Consequently, a perpendicular from the center point of each superellipse-like oval lies on the axis of the hollow shaft in the plane of each superellipse-like oval.
(27) FIG. 8 shows two of the magnetization paths 01 of a sixth preferred embodiment of the arrangement according to the invention. In this embodiment, the planes encompassing the magnetization paths 01 or the superellipse-like ovals are each inclined at an angle relative to the axis (not shown) of the hollow shaft. The angle is variable. The edge lengths a and b of the longitudinal sides are likewise variable.
(28) FIG. 9 shows two of the magnetization paths 01 of a seventh preferred embodiment of the arrangement according to the invention. In this embodiment, the planes encompassing the magnetization paths 01 or the superellipse-like ovals are each inclined at an angle relative to the axis (not shown) of the hollow shaft. The angle is variable. The edge lengths a and b of the longitudinal sides are likewise variable.
(29) FIG. 10 shows two of the magnetization paths 01 of an eighth preferred embodiment of the arrangement according to the invention. In this embodiment, the planes encompassing the magnetization paths 01 or the superellipse-like ovals are each arranged perpendicular relative to the axis (not shown) of the hollow shaft. The edge lengths a and b of the longitudinal sides are variable.
(30) FIG. 11 shows two of the magnetization paths 01 of a ninth preferred embodiment of the arrangement according to the invention. In this embodiment, the planes encompassing the magnetization paths 01 or the superellipse-like ovals each also encompass the axis (not shown) of the hollow shaft. The edge lengths a and b of the longitudinal sides are variable.
(31) FIG. 12 shows one of the magnetization paths 01 shown in FIG. 8 in another view. The plane of this view encompasses the axis (not shown) of the hollow shaft, so that the hollow shaft and its cylindrical lateral-face-shaped surface 02 are sectioned. In this view, the two longitudinal sides of the superellipse-like oval of the magnetization path 01 are shown. The longitudinal side running underneath the cylindrical lateral-face-shaped surface 02 can be arranged at different depths in the interior of the material of the hollow shaft.
(32) FIG. 13 shows one of the magnetization paths 01 shown in FIG. 8 in another view. The plane of this view is arranged perpendicular to the axis (not shown) of the hollow shaft, so that the hollow shaft and its cylindrical lateral-face-shaped surface 02 are sectioned. In this view, the two longitudinal sides of the superellipse-like oval of the magnetization path 01 are shown in turn. The longitudinal side running underneath the cylindrical lateral-face-shaped surface 02 can be arranged at different depths in the interior of the material of the hollow shaft.
LIST OF REFERENCE NUMBERS
(33) 01 Magnetization path 02 Cylindrical lateral-face-shaped surface
