Angle measuring device

Abstract

Angle measuring device (10) for measuring a rotation of a test element (12) over a measuring range that covers more than one full rotation of the test element (12), - with a magnetic element (14) that generates a magnetic field, - with a magnetic field sensor (20) arranged in such a way as to be close to the magnetic element (14) that the magnetic field sensor (20) can measure the magnetic field generated by the magnetic element (14), and - with a coupling device (22) that couples the rotation of the test element (12) with a movement of the magnetic element (14), - wherein the magnetic field sensor (20) is a 2D magnetic field sensor capable of measuring a two-dimensional magnetic field vector, or a 3D magnetic field sensor capable of measuring at least a three-dimensional magnetic field vector, and - wherein the coupling device (22) is designed such that the magnetic element (14) performs a rotation about a magnetic element rotation axis (18) and a translation in the direction of the magnetic element rotation axis (18) relative to the magnetic field sensor (20) when the test element (12) is rotated about a test element axis (16), - wherein the rotation angle measuring device (10) has an evaluation device (40) which is designed in such a way that it can determine and determine a rotation angle of the magnetic element (14) about the magnetic element rotation axis (18) from the measured values ​​of the magnetic field sensor (20), - wherein the evaluation device (40) is designed such that it can determine and determine an axial position of the magnetic element (14) along the magnetic element rotation axis (18) from the measured values ​​of the magnetic field sensor (20), at least within the measuring range, and - wherein the evaluation device (40) is designed such that it can determine the axial position of the magnetic element (14) from a direction of the measured magnetic field vector and determines, - wherein the magnetic element (14) is not rotationally symmetrical with respect to the magnetic element rotation axis (18), characterized in that - the magnetic element (14) has a smaller radial extent at the axial ends (68) of the magnetic element (14) than in a region (66) between the axial ends (68) of the magnetic element (14).

Claims

[1] Angle of rotation measuring device (10) for measuring a rotation of a test element (12) over a measuring range comprising more than one complete revolution of the test element (12), - with a magnetic element (14) which generates a magnetic field, - with a magnetic field sensor (20) arranged in the vicinity of the magnetic element (14) such that the magnetic field sensor (20) can measure the magnetic field generated by the magnetic element (14), and - with a coupling device (22) which couples the rotation of the test element (12) with a movement of the magnetic element (14), - wherein the magnetic field sensor (20) is a 2D magnetic field sensor that can measure a two-dimensional magnetic field vector, or a 3D magnetic field sensor that can measure at least one three-dimensional magnetic field vector, and - wherein the coupling device (22) is designed such that the magnetic element (14) performs a rotation about a magnetic element rotation axis (18) and a translation in the direction of the magnetic element rotation axis (18) relative to the magnetic field sensor (20) upon rotation of the test element (12) about a test element axis (16), - wherein the rotation angle measuring device (10) has an evaluation device (40) which is designed such that it can determine and determines a rotation angle of the magnetic element (14) about the magnetic element rotation axis (18) from the measured values of the magnetic field sensor (20), - wherein the evaluation device (40) is designed such that it can determine an axial position of the magnetic element (14) along the magnetic element rotation axis (18) from the measured values of the magnetic field sensor (20) at least in the measuring range and determines and - wherein the evaluation device (40) is designed such that it can determine and determines the axial position of the magnetic element (14) from a direction of the measured magnetic field vector, - wherein the magnetic element (14) is not magnetized rotationally symmetrically with respect to the magnetic element rotation axis (18), characterized by , that - the magnetic element (14) has a smaller radial extent at axial ends (68) of the magnetic element (14) than in a region (66) between the axial ends (68) of the magnetic element (14). [2] Rotation angle measuring device according to claim 1, characterized by , - that the magnetic field sensor (20) is arranged radially offset from the magnetic element rotation axis (18), - that the magnetic field sensor (20) is preferably aligned such that a first measuring axis of the magnetic field sensor (20) is aligned substantially parallel to the magnetic element rotation axis (18), and - that the magnetic field sensor (20) is preferably aligned such that a second measuring axis of the magnetic field sensor (20) is aligned substantially radially to the magnetic element rotation axis (18). [3] Rotation angle measuring device according to one of the preceding claims, characterized by , - that the magnetic element (14) is diametrically magnetized. [4] Rotation angle measuring device according to one of the preceding claims, characterized by , - that the magnetic element (14) has more than two, for example four, magnetic poles (S, N) and that the magnetic poles (S, N) are located on a radially outer surface (70), or - that the magnetic element (14) has more than two, for example four, magnetic poles (S, N), and that the magnetic poles (S, N) are located on axially outer surfaces (68), or - that the magnetic element (14) has more than two, for example four, magnetic poles (S, N), and that the magnetic poles (S, N) are located on the same axially outer surface (68). [5] Rotation angle measuring device according to one of the preceding claims, characterized by , - that the magnetic element (14) has a magnetization strength which varies in the axial direction. [6] Rotation angle measuring device according to one of claims 1 to 5, characterized by , - that the evaluation device (40) is designed such that the evaluation device (40) determines the axial position within the measuring range by the function F(By, Bx), where By is the magnetic field component in the direction of the magnetic element rotation axis (18), and Bx is the magnetic field component which lies radially to the magnetic element rotation axis (18), and where the function F(x, y) is defined by arctan (x / y) if y > 0, and by arctan (x / y) +180° if y < 0, or - that the evaluation device (40) is designed such that the evaluation device (40) determines the axial position within the measuring range by the function F(By, |Bx|) or by forming the arctangent (By / Bx), where By is the magnetic field component in the direction of the magnetic element rotation axis (18), and Bx is the magnetic field component that lies radially to the magnetic element rotation axis (18), and where the function F(x, y) is defined by arctan (x / y) if y > 0, and by arctan (x / y) +180° if y < 0, or - that the evaluation device (40) is designed such that the evaluation device (40) determines the axial position within the measuring range by the function F(|By|, |Bx|) or by forming the arctangent (|By| / |Bx|), where By is the magnetic field component in the direction of the magnetic element rotation axis (18), and Bx is the magnetic field component that lies radially to the magnetic element rotation axis (18), and where the function F(x, y) is defined by arctan (x / y) if y > 0, and by arctan (x / y) +180° if y < 0, or - that the evaluation device (40) is designed such that the evaluation device (40) determines the axial position within the measuring range by calculating the function F(By, √(Bz 2 +Bx 2)), where By is the magnetic field component in the direction of the magnetic element rotation axis (18), and Bx is the magnetic field component which lies radially to the magnetic element rotation axis (18), and Bz is the magnetic field component which lies perpendicular to By and Bx, and where the function F(x, y) is defined by arctan (x / y) when y > 0 and by arctan (x / y) +180° when y < 0. [7] Rotation angle measuring device according to one of claims 1 to 6, characterized by , - that the evaluation device (40) is at least partially formed in a common IC with the magnetic field sensor (20), and - that preferably the evaluation device (40) is formed at least partially on a common die with the magnetic field sensor (20). [8] Rotation angle measuring device according to one of claims 1 to 7, characterized by , - that the coupling device (22) has a magnetic element carrier (30) on which the magnetic element (14) is held, - that the coupling device (22) has an armature (24) which is arranged stationary relative to the magnetic field sensor (20) and which has a first gear element (26), and - that the magnetic element carrier (30) has a second gear element (28) which engages in the first gear element (26). [9] Rotation angle measuring device according to claim 8, characterized by , - that the armature (24) has a sleeve-shaped section, and that the first gear element (26) is an internal thread or an external thread, or - that the armature (24) has a threaded rod, and that the first gear element (26) is an external thread. [10] Rotation angle measuring device according to one of claims 1 to 9, characterized by , - that the coupling device (22) has a first coupling element (32) which is arranged or formed on the test element (12), and a second coupling element (34) which is arranged or formed on the magnetic element carrier (30) or on the magnetic element (14), and - that the first coupling element (32) and the second coupling element (34) engage in such a way that a rotation of the test element (12) is transmitted to the magnetic element carrier (30), and at the same time a translation of the first coupling element (32) to the second coupling element (34) is permitted. [11] Rotation angle measuring device according to claim 10, characterized by , - that the first coupling element (32) has a plurality of axially extending pins (36), - that the second coupling element (34) has axially extending recesses (38) on the magnetic element carrier (30), - that the pins (36) engage in the axially extending recesses (38) on the magnetic element carrier (30), wherein the recesses (38) and the pins (36) are arranged radially outwardly offset with respect to the magnetic element rotation axis (18), and - that the pins (36) have an axial extension which enables an axial displacement of the second coupling element (34) relative to the first coupling element (32). [12] Rotation angle measuring device according to claim 10, characterized by . - that the first coupling element (32) has an axial pin (52), - that the second coupling element (34) has a recess (54) on the magnetic element carrier (30), - that the axial pin (52) engages in the recess (54), wherein the recess (54) and the pin (52) are not rotationally symmetrical, so that a positive torque transmission between the pin (52) and the recess (54) is possible, and - that the pin (52) has an axial extension which enables an axial displacement of the second coupling element (34) relative to the first coupling element (32). [13] Rotation angle measuring device according to claim 10, characterized by , - that the first coupling element (32) and the second coupling element (34) are gears which mesh with one another, wherein at least one of the two gears has an axial extension which enables an axial displacement of the second coupling element (34) relative to the first coupling element (32). [14] Rotation angle measuring device according to claim 10, characterized by , - that the magnetic element carrier (30) has a carrier plate which has a central recess (42) through which the test element (12) engages, - that the second coupling element (34) is formed by the central recess (42) in the carrier plate of the magnetic element carrier (30), - that the first coupling element (32) is formed by a portion of the test element (12) which extends through the recess (42) in the carrier plate, and - that the first coupling element (32) has a plurality of axially extending grooves or tongues which cooperate with complementary grooves or tongues of the second coupling element (34) in order to achieve a rotation lock between the test element (12) and the magnetic element carrier (30). [15] Rotation angle measuring device according to one of claims 1 to 14, characterized by that the test element (12) is a steering column of a motor vehicle.

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