Axis of a magnetic torque angle sensor

Abstract

The purpose of the present invention is to obtain a shaft for a magnetic torque angle sensor in which the axial dimension of the shaft can be reduced. This shaft for a magnetic torque angle sensor comprises an angle detection rotor and a torque detection rotor that is provided adjacent to the angle detection rotor in the axial direction, the angle detection rotor having an angle detection non-magnetic body part that is formed with a cylindrical outer peripheral surface and composed of a non-magnetic body, and an angle detection magnetic body part provided on the outer peripheral surface of the angle detection non-magnetic body part and composed of a magnetic body, the torque detection rotor having a torque detection magnetic body part formed integrally with the angle detection magnetic body part and composed of a magnetic body, and the axial size of the angle detection magnetic body part changing periodically in accordance with a change in circumferential position.

Description

Technical Field

[0001] This invention relates to the axis of a magnetic torque angle sensor.

Background Art

[0002] Conventionally, a torque angle sensor including an angle sensor and a torque sensor has been known. The angle sensor and the torque sensor are arranged apart from each other in the axial direction. The angle sensor is composed of an optical rotary encoder. The angle sensor has a light emitting diode, a photo diode, and a rotating plate with slits. The light emitting diode, the photo diode, and the rotating plate with slits are arranged apart from each other in the axial direction. The rotating plate with slits is attached to the axis. The torque sensor is composed of a non-contact magnetostrictive torque sensor. The torque sensor has a magnetic body part and a magnetic sensor (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] [[ID=�5]]However, in the configuration of the torque angle sensor described in Patent Document 1, the angle sensor and the torque sensor are arranged apart from each other in the axial direction. Further, in the configuration of the torque angle sensor described in Patent Document 1, the light emitting diode, the photo diode, and the rotating plate with slits are arranged apart from each other in the axial direction. As a result, there is a problem that the axial dimension of the torque angle sensor becomes large.

[0005] This invention was made to solve the problems described above, and its purpose is to provide a shaft for a magnetic torque angle sensor that can reduce its axial dimensions. [Means for solving the problem]

[0006] The shaft of the magnetic torque angle sensor according to this invention comprises an angle detection rotor and a torque detection rotor provided adjacent to the angle detection rotor in the axial direction. The angle detection rotor has a cylindrical outer surface and includes an angle detection non-magnetic portion made of a non-magnetic material and an angle detection magnetic portion provided on the outer surface of the angle detection non-magnetic portion and made of a magnetic material. The torque detection rotor has a torque detection magnetic portion made of a magnetic material, formed integrally with the angle detection magnetic portion, and the axial size of the angle detection magnetic portion changes periodically in accordance with the change in position in the circumferential direction. Furthermore, in the shaft of the magnetic torque angle sensor according to this invention, the angle detection rotor has a cylindrical central part for angle detection, and the non-magnetic part for angle detection is formed in a ring shape and is provided on the outer circumferential surface of the central part for angle detection. Furthermore, in the shaft of the magnetic torque angle sensor according to this invention, the non-magnetic material portion for angle detection is formed in a cylindrical shape. Furthermore, in the shaft of the magnetic torque angle sensor according to this invention, the torque detection rotor has a non-magnetic torque detection portion made of a non-magnetic material with a cylindrical outer surface, and the torque detection magnetic portion is provided on the outer surface of the non-magnetic torque detection portion. Furthermore, in the shaft of the magnetic torque angle sensor according to this invention, the non-magnetic material portion for torque detection is formed in a cylindrical shape. Furthermore, in the shaft of the magnetic torque angle sensor according to this invention, the torque detection rotor has a cylindrical torque detection center, and the non-magnetic torque detection part is formed in a ring shape and is provided on the outer circumferential surface of the torque detection center. [Effects of the Invention]

[0007] The shaft of the magnetic torque angle sensor according to this invention allows for a reduction in axial dimensions. [Brief explanation of the drawing]

[0008] [Figure 1] This is a front view showing a magnetic torque angle sensor equipped with the shaft of a magnetic torque angle sensor according to Embodiment 1. [Figure 2] Figure 1 is a cross-sectional view showing the main components of a magnetic torque angle sensor. [Figure 3] Figure 1 is a front view showing the axis of the magnetic torque angle sensor. [Figure 4] Figure 3 is a front view showing the main part of the shaft of the magnetic torque angle sensor. [Figure 5] This is a cross-sectional view taken along the VV line in Figure 3. [Figure 6] This is a cross-sectional view taken along the line VI-VI in Figure 3. [Figure 7] Figure 1 is a perspective view showing the fixed body. [Figure 8] Figure 7 is a cross-sectional view showing the fixed body. [Figure 9] This is a cross-sectional view showing the rotor for detecting the angle on the axis of a magnetic torque angle sensor according to Embodiment 2. [Figure 10] This is a cross-sectional view showing a torque detection rotor on the axis of a magnetic torque angle sensor according to Embodiment 2. [Figure 11] This is a cross-sectional view showing a torque detection rotor on the axis of a magnetic torque angle sensor according to Embodiment 3. [Modes for carrying out the invention]

[0009] Embodiment 1. Figure 1 is a front view showing a magnetic torque angle sensor with an axis according to Embodiment 1. Figure 2 is a cross-sectional view showing the main part of the magnetic torque angle sensor of Figure 1.

[0010] The magnetic torque angle sensor includes a shaft 1 and a magnetic pole portion 2.

[0011] The direction along the axis of the shaft 1 is defined as the axial direction. The direction along the radius of a circle centered on the axis of the shaft 1 in a plane orthogonal to the axis of the shaft 1 is defined as the radial direction. The direction along the circumference of a circle centered on the axis of the shaft 1 in a plane orthogonal to the axis of the shaft 1 is defined as the circumferential direction.

[0012] The magnetic pole portion 2 is formed in an annular shape. The shaft 1 is arranged to face the magnetic pole portion 2 in the radial direction. The shaft 1 is rotatable circumferentially about its axis at the center of the magnetic pole portion 2. A bearing (not shown) is provided between the shaft 1 and the magnetic pole portion 2.

[0013] FIG. 3 is a front view showing the shaft 1 of the magnetic torque angle sensor of FIG. 1. FIG. 4 is a front view showing the main part of the shaft 1 of the magnetic torque angle sensor of FIG. 3. FIG. 5 is a cross-sectional view taken along the line V-V of FIG. 3 as viewed in the direction of the arrow. FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 3 as viewed in the direction of the arrow.

[0014] The shaft 1 of the magnetic torque angle sensor according to Embodiment 1 includes a first shaft member 3, an angle detection rotor 4, a torque detection rotor 5, and a second shaft member 6.

[0015] The first shaft member 3, the angle detection rotor 4, the torque detection rotor 5, and the second shaft member 6 are arranged axially in the order of the first shaft member 3, the angle detection rotor 4, the torque detection rotor 5, and the second shaft member 6.

[0016] The first shaft member 3 is formed in a cylindrical shape. The first shaft member 3 is arranged to extend in the axial direction.

[0017] The angle detection rotor 4 has an angle detection central portion 401, an angle detection non-magnetic body portion 402, and an angle detection magnetic body portion 403.

[0018] The angle detection center 401 is formed in a cylindrical shape. The angle detection center 401 is positioned to extend in the axial direction. The angle detection center 401 is connected to the first axial member 3.

[0019] The angle detection non-magnetic part 402 is formed in a ring shape. The angle detection non-magnetic part 402 is provided on the outer circumferential surface 404 of the angle detection center 401. The angle detection non-magnetic part 402 has a cylindrical outer circumferential surface 405. The angle detection non-magnetic part 402 is made of a non-magnetic material. Methods for providing the angle detection non-magnetic part 402 on the outer circumferential surface 404 of the angle detection center 401 include, for example, coating, thermal spraying, and press-fitting.

[0020] The angle-detecting magnetic material portion 403 is provided on the outer circumferential surface 405 of the angle-detecting non-magnetic material portion 402. The angle-detecting magnetic material portion 403 is made of a magnetic material. Methods for providing the angle-detecting magnetic material portion 403 on the outer circumferential surface 405 of the angle-detecting non-magnetic material portion 402 include, for example, coating, thermal spraying, and press-fitting.

[0021] The axial size of the angle-detecting magnetic material 403 changes periodically in accordance with the change in its circumferential position.

[0022] The torque detection rotor 5 has a torque detection center 501 and a torque detection magnetic material part 502.

[0023] The torque detection center 501 is formed in a cylindrical shape. The torque detection center 501 is positioned to extend in the axial direction. The torque detection center 501 is connected to the angle detection center 401.

[0024] The torque detection magnetic element 502 is provided on the outer circumferential surface 503 of the torque detection central part 501. The torque detection magnetic element 502 is made of a magnetic material. Methods for providing the torque detection magnetic element 502 on the outer circumferential surface 503 of the torque detection central part 501 include, for example, coating, thermal spraying, and press-fitting.

[0025] The torque detection magnetic element 502 is integrally formed with the angle detection magnetic element 403. In other words, the angle detection magnetic element 403 and the torque detection magnetic element 502 are made of the same material and are a single component formed integrally in a way that prevents disassembly. In Figure 4, the angle detection magnetic element 403 and the torque detection magnetic element 502 are omitted.

[0026] The axial size of the torque-detecting magnetic element 502 does not change with respect to changes in its circumferential position. In other words, the axial size of the torque-detecting magnetic element 502 remains constant regardless of changes in its circumferential position.

[0027] The second shaft member 6 is formed in a cylindrical shape. The second shaft member 6 is arranged to extend in the axial direction. The second shaft member 6 is connected to the torque detection center 501.

[0028] The first shaft member 3, the angle detection center 401, the torque detection center 501, and the second shaft member 6 are integrally formed with each other. In other words, the first shaft member 3, the angle detection center 401, the torque detection center 501, and the second shaft member 6 are made of the same material and are a single, integrally formed component that cannot be disassembled. As the material constituting the first shaft member 3, the angle detection center 401, the torque detection center 501, and the second shaft member 6, for example, an alloy suited to the application of shaft 1 is used. An example of an alloy suited to the application of shaft 1 is structural alloy steel.

[0029] Either the first shaft member 3 or the second shaft member 6 is connected to a transmission shaft (not shown), and the other is connected to a transmission shaft (not shown) which is connected to a drive device (not shown).

[0030] Figure 7 is a perspective view showing the magnetic pole section 2 of Figure 1. Figure 8 is a cross-sectional view showing the magnetic pole section 2 of Figure 7. The magnetic pole section 2 comprises an angle detection stator 7 and a torque detection stator 8.

[0031] The angle detection stator 7 includes an angle detection stator core 701 and a plurality of angle detection coils 702. The angle detection stator core 701 includes an annular yoke portion 703 and a plurality of teeth portions 704.

[0032] Multiple teeth 704 are arranged in a circumferential direction. Each tooth 704 is positioned to extend radially inward from the yoke 703. Each of the multiple teeth 704 is provided with one angle detection coil 702.

[0033] The torque detection stator 8 includes a torque detection stator core 801 and a plurality of torque detection coils 802. The torque detection stator core 801 includes an annular yoke portion 803 and a plurality of teeth portions 804.

[0034] Multiple teeth 804 are arranged in a circumferential direction. Each tooth 804 is positioned to extend radially inward from the yoke 803. Each of the multiple teeth 804 is provided with one torque detection coil 802.

[0035] Next, a method for detecting angles using a magnetic torque angle sensor will be described. The angle detection rotor 4 and angle detection stator 7 are arranged facing each other in the radial direction.

[0036] Each of the angle detection coils 702 includes an excitation coil and an angle detection coil. The excitation coil magnetizes the angle detection magnetic material 403 of the angle detection rotor 4. The gap permeance between the angle detection magnetic material 403 and the angle detection coil changes in accordance with the angle of the angle detection rotor 4.

[0037] The magnetic torque angle sensor detects the angle of the angle detection rotor 4 using the change in gap permeance between the angle detection magnetic element 403 and the angle detection coil.

[0038] Next, a method for detecting torque using a magnetic torque angle sensor will be described. The torque detection rotor 5 and torque detection stator 8 are arranged facing each other in the radial direction.

[0039] The impedance of each of the multiple torque detection coils 802 changes in response to the torque acting on the torque detection rotor 5.

[0040] The magnetic torque angle sensor detects the torque acting on the torque detection rotor 5 by using the change in impedance of each of the multiple torque detection coils 802.

[0041] As described above, the shaft 1 of the magnetic torque angle sensor according to Embodiment 1 comprises an angle detection rotor 4 and a torque detection rotor 5 provided adjacent to the angle detection rotor 4 in the axial direction. The angle detection rotor 4 has a cylindrical outer surface 405 formed thereon and includes an angle detection non-magnetic part 402 made of a non-magnetic material, and an angle detection magnetic part 403 provided on the outer surface 405 of the angle detection non-magnetic part 402 and made of a magnetic material. The torque detection rotor 5 has a torque detection magnetic part 502 made of a magnetic material, which is formed integrally with the angle detection magnetic part 403. The axial size of the angle detection magnetic part 403 changes periodically in accordance with the change in circumferential position. With this configuration, the torque detection rotor 5 is provided adjacent to the angle detection rotor 4 in the axial direction, and the torque detection magnetic part 502 is formed integrally with the angle detection magnetic part 403. This makes it possible to reduce the axial dimension of the shaft 1 of the magnetic torque angle sensor.

[0042] Furthermore, in the shaft 1 of the magnetic torque angle sensor according to Embodiment 1, the angle detection rotor 4 has a cylindrical angle detection center 401. The angle detection non-magnetic part 402 is formed in a ring shape and is provided on the outer circumferential surface 404 of the angle detection center 401. With this configuration, the strength of the angle detection rotor 4 can be improved by using an alloy suitable for the application of the shaft 1 as the material constituting the angle detection center 401.

[0043] Embodiment 2. Figure 9 is a cross-sectional view showing the angle detection rotor 4 on the axis 1 of the magnetic torque angle sensor according to Embodiment 2. Figure 10 is a cross-sectional view showing the torque detection rotor 5 on the axis 1 of the magnetic torque angle sensor according to Embodiment 2.

[0044] In the shaft 1 of the magnetic torque angle sensor according to Embodiment 2, the angle detection rotor 4 has an angle detection non-magnetic part 402 and an angle detection magnetic part 403. In the shaft 1 of the magnetic torque angle sensor according to Embodiment 2, the angle detection rotor 4 does not have an angle detection central part 401.

[0045] The non-magnetic part 402 for angle detection is formed in a cylindrical shape. The magnetic part 403 for angle detection is provided on the outer circumferential surface 405 of the non-magnetic part 402 for angle detection. Methods for providing the magnetic part 403 for angle detection on the outer circumferential surface 405 of the non-magnetic part 402 for angle detection include, for example, coating, thermal spraying, and press-fitting.

[0046] In the shaft 1 of the magnetic torque angle sensor according to Embodiment 2, the torque detection rotor 5 has a non-magnetic torque detection portion 504 and a magnetic torque detection portion 502. In the shaft 1 of the magnetic torque angle sensor according to Embodiment 2, the torque detection rotor 5 does not have a torque detection center portion 501.

[0047] The non-magnetic torque detection portion 504 is formed in a cylindrical shape. The magnetic torque detection portion 502 is provided on the outer circumferential surface 505 of the non-magnetic torque detection portion 504. Methods for providing the magnetic torque detection portion 502 on the outer circumferential surface 505 of the non-magnetic torque detection portion 504 include, for example, coating, thermal spraying, and press-fitting.

[0048] The first shaft member 3, the non-magnetic part 402 for angle detection, the non-magnetic part 504 for torque detection, and the second shaft member 6 are integrally formed with each other. In other words, the first shaft member 3, the non-magnetic part 402 for angle detection, the non-magnetic part 504 for torque detection, and the second shaft member 6 are made of the same material and are a single, integrally formed component that cannot be disassembled. The first shaft member 3, the non-magnetic part 402 for angle detection, the non-magnetic part 504 for torque detection, and the second shaft member 6 are made of non-magnetic material.

[0049] The other configurations of the axis 1 of the magnetic torque angle sensor according to Embodiment 2 are the same as those of the axis 1 of the magnetic torque angle sensor according to Embodiment 1.

[0050] As described above, in the shaft 1 of the magnetic torque angle sensor according to Embodiment 2, the non-magnetic part 402 for angle detection is formed in a cylindrical shape. With this configuration, it is not necessary to make the non-magnetic part 402 for angle detection ring-shaped and provide it on the outer circumferential surface 404 of the central part 401 for angle detection. This makes it easier to manufacture the non-magnetic part 402 for angle detection.

[0051] Furthermore, in the shaft 1 of the magnetic torque angle sensor according to Embodiment 2, the torque detection rotor 5 has a non-magnetic torque detection portion 504 made of a non-magnetic material, with a cylindrical outer surface 505 formed thereon. The torque detection magnetic portion 502 is provided on the outer surface 505 of the torque detection non-magnetic portion 504. With this configuration, the magnetic torque angle sensor can efficiently detect changes in the magnetoresistance of the torque detection magnetic portion 502. This improves the torque detection accuracy of the magnetic torque angle sensor.

[0052] Furthermore, in the shaft 1 of the magnetic torque angle sensor according to Embodiment 2, the non-magnetic torque detection portion 504 is formed in a cylindrical shape. This configuration makes it easy to manufacture the non-magnetic torque detection portion 504.

[0053] In the description of the shaft 1 of the magnetic torque angle sensor according to Embodiment 2, a configuration was described in which the first shaft member 3 and the second shaft member 6 are each made of a non-magnetic material. However, the configuration is not limited to this. At least one of the first shaft member 3 and the second shaft member 6 may be made of a magnetic material, for example. When the first shaft member 3 is made of a magnetic material, a method for connecting the non-magnetic part 402 for angle detection to the first shaft member 3 may be friction welding, for example. When the second shaft member 6 is made of a magnetic material, a method for connecting the central part 501 for torque detection to the second shaft member 6 may be friction welding, for example.

[0054] Embodiment 3. Figure 11 is a cross-sectional view showing a torque detection rotor on the shaft of a magnetic torque angle sensor according to Embodiment 3. On the shaft 1 of the magnetic torque angle sensor according to Embodiment 3, the torque detection rotor 5 has a torque detection center 501, a torque detection non-magnetic part 504, and a torque detection magnetic part 502.

[0055] The non-magnetic torque detection portion 504 is formed in a ring shape. The non-magnetic torque detection portion 504 is provided on the outer circumferential surface 503 of the torque detection center 501. Methods for providing the non-magnetic torque detection portion 504 on the outer circumferential surface 503 of the torque detection center 501 include, for example, coating, thermal spraying, and press-fitting.

[0056] The non-magnetic torque detection portion 504 has a cylindrical outer surface 505. The magnetic torque detection portion 502 is provided on the outer surface 505 of the non-magnetic torque detection portion 504. Methods for providing the magnetic torque detection portion 502 on the outer surface 505 of the non-magnetic torque detection portion 504 include, for example, coating, thermal spraying, and press-fitting.

[0057] The other configurations of the shaft 1 of the magnetic torque angle sensor according to Embodiment 3 are the same as those of the shaft 1 of the magnetic torque angle sensor according to Embodiment 1. Note that, similar to the shaft 1 of the magnetic torque angle sensor according to Embodiment 2, the non-magnetic material portion 402 for angle detection may be formed in a cylindrical shape.

[0058] As described above, in the shaft 1 of the magnetic torque angle sensor according to Embodiment 3, the torque detection rotor 5 has a cylindrical torque detection center 501. The non-magnetic torque detection portion 504 is formed in a ring shape and is provided on the outer circumferential surface 503 of the torque detection center 501. With this configuration, the strength of the torque detection rotor 5 can be improved by using an alloy suitable for the application of the shaft 1 as the material constituting the torque detection center 501.

[0059] In each embodiment of the magnetic torque angle sensor, the shaft 1 was described in which the axial size of the angle detection magnetic material 403 changes periodically in a sinusoidal pattern in response to changes in the circumferential position. However, the invention is not limited to this configuration. The axial size of the angle detection magnetic material 403 may also change periodically in a triangular wave pattern, a rectangular wave pattern, or a multi-step stepped wave pattern in response to changes in the circumferential position.

[0060] Although the shaft 1 of the magnetic torque angle sensor according to each preferred embodiment has been described above, the shaft 1 of the magnetic torque angle sensor according to each embodiment described above is not limited to the shaft 1 of the magnetic torque angle sensor according to each embodiment described above. Various modifications and transformations can be made to the shaft 1 of the magnetic torque angle sensor according to each embodiment described above without departing from the scope described in the claims. [Explanation of Symbols]

[0061] 1 Axis, 2 Magnetic pole section, 3 First axis member, 4 Rotor for angle detection, 5 Rotor for torque detection, 6 Second axis member, 7 Stator for angle detection, 8 Stator for torque detection, 401 Center for angle detection, 402 Non-magnetic part for angle detection, 403 Magnetic part for angle detection, 404 Outer surface, 405 Outer surface, 501 Center for torque detection, 502 Magnetic part for torque detection, 503 Outer surface, 504 Non-magnetic part for torque detection, 505 Outer surface, 701 Stator core for angle detection, 702 Coil for angle detection, 703 Yoke section, 704 Teeth section, 801 Stator core for torque detection, 802 Coil for torque detection, 803 Yoke section, 804 Teeth section.

Claims

1. Angle detection rotor (4), A torque detection rotor (5) is provided adjacent to the angle detection rotor (4) in the axial direction, Equipped with, The angle detection rotor (4) is A cylindrical outer surface (405) is formed, and an angle detection non-magnetic part (402) made of a non-magnetic material is provided, An angle detection magnetic material part (403) is provided on the outer peripheral surface (405) of the angle detection non-magnetic material part (402) and is made of a magnetic material, It has, The torque detection rotor (5) has a torque detection magnetic body part (502) made of a magnetic material, which is formed integrally with the angle detection magnetic body part (403), The axial size of the angle detection magnetic material (403) is the axis of the magnetic torque angle sensor, which changes periodically in accordance with the change in position in the circumferential direction.

2. The angle detection rotor (4) has a cylindrical angle detection center (401), The shaft of the magnetic torque angle sensor according to claim 1, wherein the non-magnetic part for angle detection (402) is formed in a ring shape and is provided on the outer circumferential surface (404) of the central part for angle detection (401).

3. The shaft of the magnetic torque angle sensor according to claim 1, wherein the non-magnetic part (402) for angle detection is formed in a cylindrical shape.

4. The torque detection rotor (5) has a torque detection non-magnetic part (504) made of a non-magnetic material, The shaft of a magnetic torque angle sensor according to any one of claims 1 to 3, wherein the torque detection magnetic material portion (502) is provided on the outer circumferential surface (505) of the torque detection non-magnetic material portion (504).

5. The shaft of the magnetic torque angle sensor according to claim 4, wherein the non-magnetic torque detection portion (504) is formed in a cylindrical shape.

6. The torque detection rotor (5) has a cylindrical torque detection center (501), The shaft of the magnetic torque angle sensor according to claim 4, wherein the non-magnetic torque detection portion (504) is formed in a ring shape and is provided on the outer circumferential surface (503) of the torque detection central part (501).

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