Rotational angle detection assembly

Abstract

The invention relates to a rotational angle detection assembly comprising an inductive detection device (30) for detecting the rotational angle of a shaft (100) which can be rotated about a rotational axis (D), wherein the inductive detection device (30) has an induction rotor (36), a stator (34), and an electronic circuit (38); and a magnetic detection device (20) for detecting the rotational angle of the shaft (100) which can be rotated about the rotational axis (D). The magnetic detection device (20) has a magnetic field sensor (22) and a permanent magnet (24), and the permanent magnet (24) and the induction rotor (36) are arranged coaxially to each other in a rotationally fixed manner on the shaft (100).

Description

[0001] Angle of rotation detection arrangement

[0002] The invention relates to a rotation angle detection arrangement with an inductive detection device for detecting a rotation angle of a shaft rotatable or rotating about a rotation axis, wherein the inductive detection device has an induction rotor, a stator and an electronic circuit, a magnetic detection device for detecting the rotation angle of the shaft rotatable about a rotation axis, wherein the magnetic detection device has a magnetic field sensor and a permanent magnet.

[0003] Such angle of rotation detection arrangements are also referred to as combination sensors and comprise a combination of differently designed sensor units which do not influence each other during operation. Optical, capacitive, magnetic, inductive and sensor units operating according to other functional principles can be combined with one another. A rotation angle detection arrangement known, for example, from EP 2 180296 A1 comprises an inductive detection device and a magnetic detection device, i.e. an inductive sensor unit and a magnetic sensor unit, wherein the angle of rotation of a single shaft rotating about a rotation axis is determined with both sensor units. The advantage of combining the inductive detection device and the magnetic detection device is the use of two completely independently operating measuring principles.This ensures maximum safety, as several independent channels are available for signal evaluation and can be used to determine the angle of rotation of the rotating shaft.

[0004] The embodiment of the rotation angle detection arrangement disclosed in EP 2 180 296 A1 comprises a first spur gear connected to a shaft in a rotationally fixed manner, and a second spur gear meshing with the first spur gear. An induction rotor of the inductive detection device is arranged on the first spur gear, and the permanent magnet of the magnetic detection device is arranged on the second spur gear. Thus, the rotation angle of the first spur gear is determined by the inductive detection device, and the rotation angle of the second spur gear is determined by the magnetic detection device. The direct coupling between the two spur gears, the rotationally fixed connection of the first spur gear to the shaft, and a conversion of the rotation angle of the second spur gear using an existing transmission ratio between the spur gears by both sensor units allow the rotation angle of the shaft to be determined independently of one another.

[0005] The disadvantage of such a design of the rotation angle detection arrangement is that the required spur gear stage requires a relatively large installation space, particularly in the radial direction of the shaft, and the manufacturing effort is relatively high.

[0006] The object of the invention is to provide a rotation angle detection arrangement which is designed to save installation space and is simple and cost-effective to manufacture.

[0007] The invention is solved by the features of claim 1.

[0008] According to the invention, the permanent magnet and the induction rotor are arranged coaxially to each other and rotationally fixed to the shaft. Due to the rotationally fixed connection of the permanent magnet and the induction rotor, they rotate together with the shaft around a common axis of rotation, namely the shaft's axis of rotation.

[0009] This allows the angle of rotation detection assembly to be designed compactly, while the installation space—i.e., the radial and axial installation space relative to the shaft's rotational axis—is relatively small. Furthermore, no additional components, such as a spur gear stage, are required, thus reducing manufacturing costs.

[0010] Preferably, the induction rotor and the permanent magnet are arranged at a common end of the rotating shaft, wherein the induction rotor and the permanent magnet are preferably arranged in a common first transverse plane, and the permanent magnet is preferably surrounded by the induction rotor. This allows the rotation angle determination device to be designed particularly compactly in the axial direction. Alternatively, the permanent magnet is arranged at a distance from the induction rotor in the direction of the rotation axis.

[0011] Preferably, the stator and the magnetic field sensor are also arranged coaxially or concentrically with each other. The magnetic field sensor is preferably arranged radially centrally relative to the shaft's rotational axis, and the stator, which rotates in the circumferential direction, radially surrounds the magnetic field sensor. As a result, the induction rotor, the permanent magnet, the magnetic field sensor, and the stator are arranged coaxially or concentrically with each other. This allows for a particularly compact design of the angle of rotation detection device.

[0012] The magnetic field sensor is preferably designed as a Hall, GMR, or AMR sensor and, in conjunction with the permanent magnet, is based on well-known operating principles. This allows for a simple and cost-effective design.

[0013] In a preferred embodiment, the stator and the magnetic field sensor are arranged on a common circuit board. As a result, the rotation angle determination device comprises a single circuit board, allowing the rotation angle determination device to be manufactured simply and cost-effectively.

[0014] Preferably, the stator and the magnetic field sensor are arranged in a common second transverse plane. This allows the circuit board to be constructed particularly simply, i.e., from a single plate, and the axial installation space of the rotation angle detection arrangement can be reduced. The two transverse planes are to be understood as being aligned perpendicular to the axial direction of the shaft. The two transverse planes are arranged at a distance from each other in the axial direction.

[0015] In a preferred embodiment, the inductive detection device and the magnetic detection device are at least partially arranged in a common housing. In particular, the magnetic field sensor, the stator, and the electronic circuit are arranged in the housing. This allows the rotation angle detection arrangement to be designed as a compact unit.

[0016] Preferably, the shaft is associated with a drive-by-wire system. Drive-by-wire or X-by-wire means that the connection between an actuating element, such as an accelerator pedal, and the vehicle system to be actuated, such as a braking system, is established by signal transmission between the actuating element and the associated vehicle system, rather than by a mechanical coupling. H"X" can stand for any vehicle function. For example, a steer-by-wire system refers to a steering system, and a brake-by-wire system refers to a braking system.

[0017] Such drive-by-wire systems are generally safety-relevant devices in a vehicle and must function reliably. Therefore, a rotation angle detection arrangement with two reliably functioning sensor units—i.e., the inductive detection device and the magnetic detection device—is particularly suitable.

[0018] This provides a rotation angle detection arrangement which is designed to save installation space and is simple and cost-effective to manufacture.

[0019] The invention is explained in more detail below with reference to the accompanying drawings. These show:

[0020] Figure 1 A rotation angle detection arrangement in cross section.

[0021] Figure 1 shows a rotation angle detection arrangement 10, which is used to detect the rotation angle of a shaft 100 of a drive-by-wire system that can be rotated about a rotation axis D during operation. For example, the shaft 100 is assigned to a brake pedal of a brake-by-wire system. The rotation angle detection arrangement 10 comprises a magnetic detection device 20, an inductive detection device 30, and an evaluation unit 48, wherein the magnetic detection device 20 and the inductive detection device 30 detect the rotation angle of the shaft 100 independently of one another. This provides redundant detection of the rotation angle of the shaft 100.

[0022] The magnetic detection device 20 and the inductive detection device 30 are partially arranged in an interior space 18 of a housing 12 that is fluid-tightly sealed to the outside environment. The housing 12 has a pot-shaped base body 14 and a cover 16 that define the interior space 18. The housing 12 is preferably made of a material permeable to a magnetic field, in particular plastic.

[0023] The magnetic detection device 20 comprises a magnetic field sensor 22 and a permanent magnet 24. The permanent magnet 24 is arranged on an end face of the shaft 100. The magnetic field sensor 22 is designed as a Hall sensor and is arranged on a circuit board 50 located in the interior 18. The magnetic field sensor 22 is arranged in the region of the permanent magnet 24 and is connected to the evaluation unit 48 via electrical lines of the circuit board 50.

[0024] The detection of the angle of rotation of the shaft 100 by the magnetic detection device 20 is carried out by means of a generally known principle, wherein a magnetic field changing during a rotational movement is detected by the magnetic field sensor 22 and the angle of rotation of the shaft 100 is determined therefrom.

[0025] The inductive detection device 30 has at least two excitation coils 32, a stator 34, an induction rotor 36, and an electronic circuit 38. The excitation coils 32 are arranged on the circuit board 50 and can be supplied with alternating current. The induction rotor 36 is arranged on the shaft 100 in a rotationally fixed manner via a support element 40, wherein the support element 40 is preferably arranged in the region of the end face of the shaft 100 receiving the permanent magnet 24 such that the induction rotor 36 and the permanent magnet 24 are arranged in a common, first transverse plane Q1. The stator 34 is also arranged on the circuit board 50 and has a plurality of receiving elements 35, in particular receiving conductor loops, which are arranged distributed in the circumferential direction.The receiving elements 35 are connected to the electronic circuit 38 via electrical lines of the printed circuit board 50, wherein the electronic circuit 38 is in turn connected to the evaluation unit 48 arranged on the printed circuit board 50 via electrical lines of the printed circuit board 50.

[0026] To detect the angle of rotation of shaft 100 by the inductive detection device 20, the excitation coils 32 are supplied with alternating current by the electronic circuit 38, creating an electromagnetic field. This electromagnetic field induces an electrical voltage in the induction rotor 36 and in the receiving elements 35 of the stator 34. The induction rotor 36 forms a short-circuit winding, creating a short-circuit current, which in turn creates an electromagnetic field. Due to a special shape of the short-circuit winding, the magnetic fields cancel each other out in predefined areas and not in others. The receiving elements 35 of the stator 34 detect the electromagnetic field resulting from the two electromagnetic fields, from which the angle of rotation of shaft 100 is determined.

[0027] In order to provide the smallest possible installation space for the rotation angle detection arrangement 10, the permanent magnet 24, the induction rotor 36, the stator 24, the excitation coils 32, and the magnetic field sensor 22 are arranged coaxially to one another and nested within one another. On the shaft side, the permanent magnet 24 is arranged radially centrally on the end face of the shaft 100, wherein the permanent magnet 24 is arranged together with the induction rotor 26 in the first transverse plane Q1 and is radially surrounded by the induction rotor 36, which is arranged radially on the outside. On the circuit board side, the magnetic field sensor 22 is arranged radially centrally with respect to the axis of rotation D, wherein the stator 34 with the receiving elements 35 radially surrounds the magnetic field sensor 22 and the excitation coils 32, in turn, radially border the stator 34. The magnetic field sensor 22, the excitation coils 32 and the stator 34 are arranged in a common, second transverse plane Q2.Thus, the angle of rotation detection arrangement 10 has only two transverse planes Q1, Q2, in which all components of the magnetic and inductive detection devices 20, 30 are arranged, whereby the axial installation space of the angle of rotation detection arrangement 10 is relatively small. Due to the coaxial and nested arrangement of the components of the magnetic and inductive detection devices 20, 30, the radial installation space of the angle of rotation detection arrangement 10 is also relatively small.

[0028] List of reference symbols

[0029] 10 Angle of rotation detection arrangement

[0030] 12 housings

[0031] 14 basic bodies

[0032] 16 lids

[0033] 18 Interior

[0034] 20 Magnetic detection device

[0035] 22 Magnetic field sensor

[0036] 24 permanent magnet

[0037] 30 Inductive detection device

[0038] 32 Excitation coil

[0039] 34 Stator

[0040] 35 receiving elements

[0041] 36 Induction rotor

[0042] 38 Electronic circuit

[0043] 40 support element

[0044] 48 evaluation unit

[0045] 50 circuit boards

[0046] Q1 First transverse level

[0047] Q2 Second transverse plane

[0048] D axis of rotation

Claims

Rotation angle detection arrangement Patent claims 1. A rotation angle detection arrangement, comprising an inductive detection device (30) for detecting a rotation angle of a shaft (100) rotatable about a rotation axis (D), wherein the inductive detection device (30) has an induction rotor (36), a stator (34) and an electronic circuit (38), a magnetic detection device (20) for detecting the rotation angle of the shaft (100) rotatable about the rotation axis (D), wherein the magnetic detection device (20) has a magnetic field sensor (22) and a permanent magnet (24), characterized in that the permanent magnet (24) and the induction rotor (36) are arranged on the shaft (100) in a rotationally fixed manner and coaxially to one another.

2. Rotation angle detection arrangement according to claim 1, characterized in that the induction rotor (36) and the permanent magnet (24) are arranged at a common end of the rotating shaft (100).

3. Rotation angle detection arrangement according to claim 1 or 2, characterized in that the induction rotor (36) and the permanent magnet (24) are arranged at a distance from one another in a common, first transverse plane (Q1) or in the direction of the axis of rotation (D).

4. Rotation angle detection arrangement according to one of the preceding claims, characterized in that the permanent magnet (24) is radially surrounded by the induction rotor (36).

5. Rotation angle detection arrangement according to one of the preceding claims, characterized in that the stator (34) and the magnetic field sensor (22) are arranged on a common circuit board (50).

6. Rotation angle detection arrangement according to one of the preceding claims, characterized in that the stator (34) and the magnetic field sensor (22) are arranged in a common, second transverse plane (Q2).

7. Rotation angle detection arrangement according to one of the preceding claims, characterized in that the magnetic field sensor (22) is radially surrounded by the stator (34).

8. Rotation angle detection arrangement according to one of the preceding claims, characterized in that the magnetic detection device (20) and the inductive detection device (30) are at least partially arranged in a common housing (12).

9. Rotation angle detection arrangement according to one of the preceding claims, characterized in that the shaft (100) is associated with a drive-by-wire system.

Images