Sensor arrangement, electric machine and electrically drivable drive assembly for motor vehicle

Abstract

The invention relates to a sensor arrangement (22) comprising an inductive rotor position sensor (9) having at least one energizable transmitting coil (15) and a receiving coil (16), the transmitting coil (15) spreading out of a first surface (20) and the receiving coil (16) spreading out of a second surface (21) which is parallel to the first surface (20) or lies in the same plane as the first surface (20), the sensor arrangement (22) further has a first sensor target (10) which can be moved relative to the transmitting coil (15) and the receiving coil (16) such that it always lies outside the first surface (20) and the second surface (21) and the orthogonal projection (23) thereof.

Description

Technical Field

[0001] This invention relates to a sensor arrangement including an inductive rotor position sensor having at least one energized transmitting coil and a receiving coil, wherein the transmitting coil extends outwards to form a first surface, and the receiving coil extends outwards to form a second surface parallel to or located in the same plane as the first surface. The invention also relates to an electric motor and an electrically driven drive assembly for a motor vehicle. Background Technology

[0002] In motor vehicles, electric motors are increasingly being used as drive systems to replace internal combustion engines that rely on fossil fuels. Significant work has been done to improve the everyday usability of electric drives and provide users with the usual driving comfort.

[0003] A detailed description of electric drives can be found in ATZ Volume 113, Issue 5, 2011, pp. 360-365, by Erik Schneider, Frank Fickl, Bernd Cebulski, and Jens Liebold, entitled "High Integration and Flexibility: Electric Drive Units for Electric Vehicles." This document describes a drive unit for a vehicle axle that includes a motor arranged coaxially and concentrically with the bevel gear differential. Such drive units are also referred to as electric axles or electrically driven drive assemblies (Antriebsstrang).

[0004] In addition to purely electric drive systems, hybrid drive systems are also known. Such drive systems in hybrid vehicles typically include a combination of an internal combustion engine and an electric motor, enabling pure electric drive in urban areas while maintaining sufficient range and availability for long-distance travel. Furthermore, under certain operating conditions, both the internal combustion engine and the electric motor can drive the vehicle simultaneously.

[0005] Sensors are used in many such drive assemblies to obtain angle and speed information, such as for electric motors. These sensors, in a simplified principle, consist of a sensor rotor and a sensor stator. The sensor body is typically fixed to the motor housing. The sensor rotor is usually a rotationally symmetric component that rotates with the motor.

[0006] Permanent magnet synchronous motors are used in many of the aforementioned electric mobility applications. These motors consist of a stator that requires power and a permanent magnet rotor. The rotor typically includes a shaft, a balance disc, rotor core laminations, and magnets. The magnets are usually fixed within the rotor core laminations.

[0007] To control such electronically commutated motors, an electrical drive is applied to the stator windings based on the rotor's angular position to drive the motor. The rotor position is typically measured using a rotor position sensor and transmitted to a control unit to generate the drive signals required for the commutated motor. The rotor position sensor outputs either analog electrical quantities (e.g., voltage), signal pulses, or digital information about the absolute rotor position related to the rotor position. Such rotor position sensors are known in the prior art, and their operation typically involves a signal generator (magnetic target) fixed to the rotor reading the position via a magnetic field sensor fixed to the stator.

[0008] For example, DE 10 2009 001 353 A1 discloses an electric motor comprising a rotor with a rotor hub, a stator disposed within a stator housing, a cover plate connected to the stator housing and extending to the inner diameter of the rotor hub, the rotor being supported on the cover plate by means of a rotor bearing. The electric motor includes a rotor position sensor for detecting the rotor's magnetic field relative to the stator, the rotor position sensor being disposed on the cover plate near the rotor bearing, such that the rotor hub or a component fixed to the rotor hub can serve as the signal trajectory of the rotor position sensor.

[0009] Besides rotor position sensors that operate based on magnetic targets, inductive (induced) rotor position sensors are also known, which have the advantage of not requiring permanent magnets. However, the challenge accompanying this advantage is how to generate sufficiently accurate sensing signals through the arrangement of inductive sensors. Summary of the Invention

[0010] The object of this invention is to provide a sensor arrangement for inductive position determination that is particularly compact and inexpensive to manufacture. Furthermore, this invention aims to achieve a motor with the highest possible rotor position measurement accuracy while maintaining a compact structure. Another object of this invention is to provide a space-optimized electrically driven drive assembly.

[0011] This objective is achieved by a sensor arrangement comprising an inductive rotor position sensor having at least one energized transmitting coil and a receiving coil, wherein the transmitting coil extends out to form a first surface and the receiving coil extends out to form a second surface parallel to or in the same plane as the first surface; and the sensor arrangement further comprises a first sensing target that is movable relative to the transmitting and receiving coils such that it is always located outside the first and second surfaces and their orthogonal projections.

[0012] A key advantage of this sensor arrangement is its very compact axial structure. Furthermore, the coils can be arranged at low cost, for example, on a printed circuit board.

[0013] Preferably, the rotary position sensor is configured as an inductive rotary position sensor. Such an inductive rotary position sensor consists of two main components: a sensing target and a sensor body. The sensing target is a component manufactured or mounted on the rotor of the motor and rotates with the rotor. The sensing target can be a metal disc, a conductive pattern, or other material that causes a change in the magnetic field during rotation. Preferably, the sensing target is integrally formed with the rotor shaft.

[0014] An inductive rotary position sensor is positioned close to the target and generates a magnetic field. As the target rotates, the magnetic field sensed by the sensor changes. The sensor converts these changes into electrical signals. The sensor includes a coil through which alternating current is applied. This transmitting coil is sometimes called the TX coil. The change in the magnetic field caused by the target results in a change in magnetic flux through the sensor's receiving coil (RX coil), thereby generating a voltage in the sensor's coil, which serves as the sensor's output signal. The amplitude and / or frequency of the output signal depend on the rotor's angular position. The precise angular position of the rotor can be determined by evaluating the output signal. This can be achieved using signal processing techniques such as amplitude or phase modulation.

[0015] In the inductive rotary position sensor of the present invention, the sensing target is preferably located in a plane substantially the same as the surface of the receiving coil (RX coil), but in a position outside the receiving coil (RX coil) in the radial direction.

[0016] This rotary position sensor can provide absolute or relative angular position as an output signal.

[0017] The rotor shaft is preferably made of metal.

[0018] Advantageously, the first sensing target is rotatable along a circular trajectory around the transmitting and receiving coils, making this sensor arrangement particularly suitable for determining rotational positions, such as the rotational position of a rotor. However, theoretically, the sensing target can also have a motion trajectory deviating from the circular trajectory, such as moving along a linear path.

[0019] According to a preferred embodiment of the invention, it is conceivable that the rotor is, at least in a portion of its area, a rotor shaft in the form of a hollow shaft (i.e., a hollow shaft), and the sensing target is arranged within this hollow shaft, thereby achieving a structure in which the sensor arrangement is particularly compact in the axial direction. In this context, it is also conceivable that the rotor shaft is formed as a hollow shaft in a portion of its area, achieved by providing coaxial blind holes on the rotor shaft.

[0020] According to another preferred embodiment of the invention, it is also conceivable that the rotational position sensor extends at least partially (preferably entirely) into the hollow shaft in the axial direction, thereby also contributing to a particularly compact sensor arrangement structure in the axial direction.

[0021] According to an advantageous structure of the invention, the shaft segment can be conceived to be integrally formed with the rotor shaft, particularly as a single piece (monomeric). The advantage of this structure is that the sensing target can be manufactured in a particularly economical and precise manner using machining methods such as milling. Furthermore, since it is integrally formed, the necessity of separately mounting the sensing target is eliminated, thereby avoiding potential assembly errors.

[0022] According to another preferred embodiment of the invention, the rotary position sensor may also have a printed circuit board with a circular outer contour, which is housed in a cylindrical shaft hole with a gap and is passed over by the shaft segment when the rotor shaft rotates. In this way, particularly good space utilization can be achieved within the shaft hole. Preferably, the shaft hole has a corresponding circular inner contour, and the printed circuit board is arranged coaxially with the shaft hole.

[0023] Furthermore, according to an equally advantageous concept, the printed circuit board is conceivable to have at least one energized transmitting coil and at least one receiving coil. The combination of the transmitting and receiving coils can be used to employ different measurement methods and techniques. For example, the rotational position can be determined using the phase difference between the transmitted and received signals. This allows the sensor to be adapted to different requirements and applications. Preferably, the coils are configured for an inductive rotational position sensor.

[0024] Furthermore, the invention can be further developed such that the shaft segment includes axially extending grooves distributed circumferentially along the inner cylindrical surface. An advantage of this structure is that these grooves are easy to manufacture.

[0025] In another preferred embodiment, it is also conceivable that the rotor position sensor is completely housed within the shaft bore, which helps to provide a particularly compact motor structure in the axial direction.

[0026] Furthermore, the invention can be advantageously developed to allow the shaft hole to completely penetrate the rotor shaft axially, thus realizing it as a hollow shaft. This significantly reduces weight while allowing cooling fluid to circulate through the hollow shaft, thereby contributing to improved rotor performance.

[0027] The object of the present invention can also be achieved by an electric motor, particularly suitable for a drive assembly of a motor vehicle, comprising a stator and a rotor rotatable relative to the stator, the rotor being coupled to a rotor shaft by transmitting torque, the rotor shaft having a shaft bore extending axially from an end face at one end into the rotor shaft, wherein the motor further comprises a sensor arrangement by means of which the angular position of the rotor can be determined by a sensing target rotating with the rotor shaft, and the sensor arrangement is configured according to any one of claims 1-10.

[0028] This provides a motor that is particularly compact in the axial direction, since the rotor position sensor is arranged radially nested within the position formed by the sensing target extending along the rotor shaft.

[0029] Therefore, it is preferable to allow the rotary position sensor to interact with the sensing target without contact. By arranging the sensor inside the rotor shaft, the sensor is partially protected from electric and magnetic fields, which is advantageous for the rotor position sensor in terms of electromagnetic compatibility (EMV).

[0030] According to another preferred embodiment of the invention, the motor can be configured as an electrically excited synchronous machine.

[0031] Finally, the object of the present invention can also be achieved by an electrically driven motor drive assembly comprising the motor according to claim 11. Attached Figure Description

[0032] The present invention will be described in more detail below with reference to the figures, but the basic concept of the present invention is not limited thereto.

[0033] The diagram shown contains: Figure 1 shows a schematic axial sectional view of a motor. Figure 2 shows a cross-sectional view and an axial cross-sectional view of the rotor shaft and its rotor position sensor according to the first embodiment. Figure 3 shows a cross-sectional view and an axial cross-sectional view of the rotor shaft and its rotor position sensor according to the second embodiment. Figure 4 shows a schematic diagram of a motor vehicle equipped with an electrically driven drive assembly. Figure 5 shows a cross-sectional schematic diagram of the first implemented deformation of the transmitting coil and receiving coil of the rotor position sensor. Figure 6 shows a cross-sectional schematic diagram of a second implementation of the transmitting and receiving coils of the rotor position sensor. Figure 7 shows a cross-sectional schematic diagram of a third embodiment of the transmitting and receiving coils of the rotor position sensor. Figure 8 shows a schematic perspective view of the sensor arrangement with orthogonal projection. Figure 9 shows an axial cross-sectional view of the rotor shaft and its rotor position sensor according to the third embodiment. Figure 10 shows a cross-sectional view and an axial cross-sectional view of the rotor shaft and its rotor position sensor according to the fourth embodiment. Detailed Implementation

[0034] Figure 1 shows a motor (1), particularly for a drive assembly (2) of a motor vehicle (3), such as Figure 4 As shown.

[0035] The motor (1) includes a stator (4) and a rotor (5) rotatable relative to the stator (4), which is coupled to a rotor shaft (6) by transmitting torque, the rotor shaft (6) having a shaft hole (8) extending axially from an end face (7) at one end into the rotor shaft (6).

[0036] The motor (1) also has a rotor position sensor (9), which allows the angular position of the rotor (5) to be determined from a sensing target (10) that rotates with the rotor shaft (6). Figure 1 and Figure 2-3 The combination of these elements is clearly understood.

[0037] The rotor position sensor (9) is part of a sensor arrangement (22), such as Figure 8 As illustrated, the sensor arrangement (22) includes an inductive rotor position sensor (9) having at least one energized transmitting coil (15) and a receiving coil (16), wherein the transmitting coil (15) extends outward to a first surface (20), and the receiving coil (16) extends outward to a second surface (21) substantially coplanar with the first surface (20). In the illustrated embodiment, surfaces 20 and 21 are not strictly coplanar but parallel to each other and are arranged on the same printed circuit board (13), which typically has a thickness of 0.8–2.0 mm. Depending on the thickness of the printed circuit board (13), the receiving coil (16) and / or the transmitting coil (15) may be distributed across multiple layers. Alternatively, the receiving coil (16) and the transmitting coil (15) may be distributed within the same layer of the printed circuit board (13) or arranged in an overlapping manner.

[0038] It should be understood that multiple receiving coils can also be provided to improve accuracy and signal quality. The sensor arrangement (22) shown further includes a first sensing target (10) that is movable relative to the transmitting coil (15) and the receiving coil (16) such that it is always located outside the first surface (20) and the second surface (21) and their orthogonal projection (23). In the illustrated embodiment, the first sensing target (10) rotates along a circular trajectory around the transmitting coil (15) and the receiving coil (16). The key point of the invention is that the first sensing target (10) does not pass through surface 20, surface 21 or their orthogonal projection (23).

[0039] A shaft segment (12) is formed on the inner cylindrical surface (11) of the shaft hole (8), extending radially inward and / or outward from the shaft hole. These shaft segments (12) constitute a sensing target (10) for the rotor position sensor (9). The rotor position sensor (9) extends into the shaft hole (8) in the direction of rotation relative to the rotor shaft (6) such that when the rotor shaft (6) rotates, the sensor is passed over by at least a portion of the shaft segment (12).

[0040] The arc-shaped shaft segment (12) in cross-section is integrally formed with the rotor shaft (6), especially as a single piece (integral) formed, which is formed on the rotor shaft (6) by grooves (18) extending along the axial direction, the grooves being equidistantly distributed along the circumferential surface (11) of the inner cylindrical surface.

[0041] The rotor position sensor (9) has a disc-shaped printed circuit board (13) with a circular outer contour (14), which is coaxially and gappedly housed in a cylindrical shaft hole (8) and is passed over by the shaft segment (12) when the rotor shaft (6) rotates. Figure 9-10 As shown, the printed circuit board (13) can also be arranged outside the rotor shaft (6) so that it is not crossed by the shaft segment (12).

[0042] Since the rotor position sensor (9) is configured as an inductive sensor, the printed circuit board (13) has at least one energized transmitting coil (15) and at least one receiving coil (16). Figure 5-7 The diagram shows a variation of the transmitting coil (15) and receiving coil (16) different from those described above, wherein coils 15 and 16 are arranged along a radial plane of the printed circuit board (13). The transmitting coil (15) extends in a concentric ring along the outer circumference (outer contour) 17 of the printed circuit board (13), while the receiving coil (16) is radially located within the concentric ring transmitting coil (15). In the illustrated embodiment, the receiving coil (16) is arranged in a concentric segment shape. The receiving coil (16) indicated by the dashed line has opposite winding directions to the receiving coil (16) indicated by the solid line. As shown... Figure 6 As shown, another transmitting coil (15) or an additional turn of the transmitting coil may also exist in the radial region within the receiving coil (16), with its current direction opposite to that of the radially outer transmitting coil (15). Not all pole distributions must be implemented in the form of coils 15 and 16, such as Figure 7 The diagram shows that only a portion of the polar distribution can be implemented.

[0043] exist Figure 2-3 In the embodiment shown, the rotor position sensor (9) is completely housed in the shaft hole (8), and the shaft hole (8) extends axially through the rotor shaft (6), making it a hollow shaft.

[0044] Figure 3An embodiment of a rotor position sensor (9) is shown, wherein the sensing target (10) also has a protrusion (19) extending radially beyond the shaft segment (12) and inwardly. Therefore, in addition to rotor position determination by the shaft segment (12) radially located outside the printed circuit board (13), rotor position determination can also be achieved by the protrusion (19) spaced axially along the printed circuit board (13). In this case, at least one energized transmitting coil and at least one receiving coil can be arranged along the end face of the printed circuit board (13) facing the protrusion (19). This can help improve measurement accuracy or provide redundant rotor position sensors (9) without requiring additional installation space. As... Figure 3 As shown in the cross-section, the protrusion (19) and the shaft segment (12) are concentric ring segments with substantially the same central angle and substantially completely overlap in the circumferential direction. This is advantageous in manufacturing because the groove (18) can be milled from the rotor shaft (6) in one step.

[0045] This invention is not limited to the embodiments shown in the figures. The above description should be considered illustrative rather than restrictive. The following patent claims should be understood as meaning that the described features are present in at least one embodiment, but this does not exclude the presence of other features. If terms such as "first" and "second" are used in the claims or the above description, they are only used to distinguish two features of the same type and do not indicate any order of precedence between them. Appendix Label Table 1. Motor 2 Drivetrain 3 Motor vehicles 4. Stator 5 rotors 6. Rotor shaft 7 End face 8 shaft holes 9. Rotor position sensor 10 Sensing Targets 11. Cylindrical surface 12 shaft segments 13 Printed Circuit Boards 14 Outer contour 15. Transmitting coil 16 Receiving coil 17. Cylindrical surface 18 slots 19. Protrusion 20 sides 21 sides 22 Sensor Devices 23 Orthographic projection

Claims

1. A sensor device Includes an inductive rotor position sensor (9), It has at least one energized transmitting coil (15) and one receiving coil (16). The transmitting coil (15) unfolds into a first surface (20), and the receiving coil (16) unfolds into a second surface (21) that is parallel to or located on the same plane as the first surface (20). Its features The sensor arrangement (22) further includes a first sensing target (10) that is movable relative to the transmitting coil (15) and the receiving coil (16). So that it always lies outside the first plane (20) and the second plane (21) and their orthogonal projection (23).

2. The sensor arrangement (22) according to claim 1, characterized in that... The first sensing target (10) is rotatable along a circular trajectory around the transmitting coil (15) and the receiving coil (16).

3. The sensor arrangement (22) according to claim 1 or 2, characterized in that... The sensing target (10) is arranged in the shaft hole (8) of the rotor shaft (6).

4. The sensor arrangement (22) according to claim 3, characterized in that... A shaft segment (12) is formed on the inner cylindrical surface (11) of the shaft hole (8), extending radially into and / or out of the inner cylindrical surface, which constitutes a sensing target (10) for the rotor position sensor (9).

5. The sensor arrangement (22) according to claim 3 or 4, characterized in that... The rotor position sensor (9) is stationary in the shaft hole (8) relative to the rotor shaft (6) in the direction of rotation.

6. The sensor arrangement (22) according to claim 4 or 5, characterized in that... As the rotor shaft (6) rotates, the rotor position sensor (9) is at least partially passed over by the shaft segment (12).

7. The sensor arrangement (22) according to any one of claims 4-6, characterized in that... The shaft segment (12) is integrally formed with the rotor shaft (6), especially as a single unit.

8. The sensor arrangement (22) according to any one of claims 4-7, characterized in that... The rotor position sensor (9) has a printed circuit board (13) with a circular outer contour (14), which is housed in a cylindrical shaft hole (8) with a gap and is passed over by the shaft segment (12) when the rotor shaft (6) rotates.

9. The sensor arrangement (22) according to claim 8, characterized in that... The printed circuit board (13) carries an energized transmitting coil (15) and receiving coil (16).

10. The sensor arrangement (22) according to any one of claims 4-9, characterized in that... The shaft segment (12) includes an axially extending groove (18) that is circumferentially distributed along the inner cylindrical surface (11).

11. Electric motors (1), especially drive assemblies (2) for motor vehicles (3), It includes a stator (4) and a rotor (5) rotatable relative to the stator (4), the rotor being coupled to a rotor shaft (6) by transmitting torque. The rotor shaft (6) has a shaft hole (8) extending axially into the rotor shaft (6) from one end face (7). The motor (1) further includes a sensor arrangement (22) by means of which the angular position of the rotor (5) can be determined by a sensing target (10) that rotates together with the rotor shaft (6). The sensor arrangement (22) is configured according to any one of claims 1-10.

12. An electrically driven motor vehicle drive assembly (2) comprising the motor (1) according to claim 11.

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