WO2007094196A1

WO2007094196A1 - Torque detector and rotating angle detector

Info

Publication number: WO2007094196A1
Application number: PCT/JP2007/051971
Authority: WO
Inventors: Kiyotaka Sasanouchi; Kouji Oike; Kiyotaka Uehira; Kouichi Santo
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2006-02-16
Filing date: 2007-02-06
Publication date: 2007-08-23

Abstract

A torque detector comprises a first rotary body connected to the input shaft side of a shaft part to be detected, a second rotary body connected to the output shaft side of the shaft part, a first detection part for detecting the rotating angle of the first rotary body, a second detection part for detecting the rotating angle of the second rotary body, and a torque detection part for detecting a torque by the difference in rotating angle between the first and second rotary bodies.

Description

Torque detection device and rotation angle detection device

Technical field

The present invention relates to a torque detection device and a rotation angle detection device used for power steering of various vehicles.

Background art

Conventionally, as a torque detection method using a rotation angle sensor, for example, a method shown in Patent Document 1 is known.

FIG. 17 is a diagram for explaining a torque detection method using a conventional rotation angle sensor 100.

The rotation angle sensor 100 includes a gear unit 59. The gear portion 59 is fixedly attached to a rotation shaft (not shown) whose rotation angle is to be detected via an engagement panel 60. The gear part 59 meshes with the gear part 62. A code plate 61 having a plurality of magnetic poles magnetized on the outer peripheral end face is attached to the gear portion 62.

[0005] With such a configuration, the gear portion 59 rotates according to the rotation of the rotation shaft to be detected, and thereby the gear portion 62 rotates. The magnetic poles provided on the code plate 61 are rotated by the rotation of the gear portion 62.

[0006] The rotation angle sensor 100 includes a detection element 63 provided to face the magnetic pole.

The detection element 63 detects the rotation angle by counting the magnetic poles passing within the unit time.

[0007] Further, by attaching such a mechanism to each of two shafts connected via a torsion bar, when a torque acts between the two shafts and a twist between the shafts occurs, By comparing the rotation angle of each shaft, the amount of applied torque could be detected.

However, in the conventional technology described above, since the rotation of the code plate 61 and the rotation of the rotation shaft to be detected are via a gear, the detection is immediately affected by the influence of a knock lash or the like. There was a problem that it was difficult to improve intelligence accuracy. Patent Document 1: Japanese Patent Laid-Open No. 11-194007

Disclosure of the invention

[0009] The present invention has been made in view of the above-described problems, and provides a torque detection device and a rotation angle detection device with high detection accuracy.

[0010] The torque detection device of the present invention includes a first rotating body coupled to the input shaft side of the shaft portion to be detected, a second rotating body coupled to the output shaft side of the shaft portion, A first detector for detecting a rotation angle of the first rotating body; a second detector for detecting a rotation angle of the second rotating body; and the rotation angles of the first rotating body and the second rotating body. It is characterized by having a torque detector that detects torque from the difference.

[0011] With such a configuration, the first rotating body and the second rotating body are directly connected to the shaft portions to be detected, and the torque is detected from the difference in rotation angle between the rotating bodies. Therefore, it is possible to provide a torque detection device with high detection accuracy that is not easily affected by knock lashes or the like.

Next, the rotation angle detection device of the present invention detects the rotation angle of the torque detection device of the present invention, a third rotation body that rotates in synchronization with the first rotation body, and the third rotation body. A third detection unit, and a rotation angle differential force between the first rotation body and the third rotation body, and an absolute angle detection unit that detects the absolute rotation angle of the first rotation body and the third rotation body. It is characterized by.

[0013] With such a configuration, it is possible to further provide a rotation angle detection device capable of detecting the absolute rotation angles of the first rotating body and the third rotating body.

[0014] Further, the absolute angle detection unit may be configured to detect an absolute rotation angle of the second rotating body and a rotational angle difference force between the second rotating body and the third rotating body.

[0015] According to such a configuration, the absolute rotation angle of the second rotating body can be further detected.

[0016] The first rotating body has a first target in which magnetic poles having different polarities are alternately arranged in the circumferential direction, and the second rotating body has magnetic poles having different polarities alternately arranged in the circumferential direction. The third rotating body has a third target in which magnetic poles having different polarities are alternately arranged in the circumferential direction, and includes a first detection unit, a second detection unit, and a second target. Each of the three detectors has a magnetic field of a magnetic pole disposed on each of the first target, the second target, and the third target. It may be configured to detect a change.

[0017] According to such a configuration, it is possible to perform optimum angle detection by combining the number of magnetic poles with a desired number.

[0018] Furthermore, the first target and the second target have a multi-pole ring magnet force in which magnetic poles having different poles are alternately arranged on the outer peripheral surface, and the third target has a configuration having a bar magnet force. Also good.

[0019] According to such a configuration, the configuration of the present invention can be realized more easily.

[0020] In addition, the first magnetic sensing element arranged to face the magnetic pole of the first target, the second magnetic sensing element arranged to face the magnetic pole of the second target, and the magnetic pole of the third target And a third magnetic sensing element disposed opposite to each other, the first detection unit detects a magnetic field change by the first magnetic detection element, and the second detection unit detects the magnetic field change by the second magnetic detection element. The third detection unit may detect the magnetic field change by the third magnetic sensing element.

[0021] According to such a configuration, the magnetic field change can be detected more accurately by using the magnetic sensing element.

[0022] Further, a fourth rotating body connected to the shaft portion and rotating in synchronization with the first rotating body may be provided, and the third rotating body may be configured to rotate by the rotation of the fourth rotating body. Good.

[0023] According to such a configuration, it is possible to further transmit the rotation on the input shaft side without affecting the rotation of the first rotating body to the third rotating body.

[0024] Further, the absolute rotation angle of the first rotating unit and the second rotating unit are compared, and an abnormality detecting unit that detects an abnormality when the difference exceeds a predetermined value is provided. Also good.

[0025] According to such a configuration, it is possible to further detect an abnormality in a mechanical or electrical device.

[0026] Further, a memory for storing signal levels of the sine wave signal and the cosine wave signal output from the first detection unit, the second detection unit, and the third detection unit, and a sine wave signal depending on the signal level And a normal part that performs normality of the cosine wave signal.

[0027] According to such a configuration, it is possible to detect the rotation angle with high accuracy by further reducing the influence of variations in sensitivity of the elements.

[0028] Furthermore, sinusoidal signals output from the first detection unit, the second detection unit, and the third detection unit. The signal level of the signal and the cosine wave signal may include a confirmation unit that confirms whether the signal level is within a predetermined value.

[0029] According to such a configuration, it is possible to detect the rotation angle while realizing higher resolution.

[0030] Further, a memory for storing the amplitude centers of the sine wave signal and the cosine wave signal output from the first detection unit, the second detection unit, and the third detection unit, and the sine wave signal and A configuration may be provided that includes a normal key section that performs normal control of the cosine wave signal.

[0031] With such a configuration as well, it is possible to detect the rotation angle with high accuracy by reducing the influence of variations in the sensitivity of the elements.

[0032] The configuration further includes a confirmation unit that confirms whether the amplitude center of the signal output from the first detection unit, the second detection unit, and the third detection unit is within a predetermined value. Also good.

[0033] According to such a configuration, the rotation angle can be detected with high accuracy by excluding the influence when the apparatus is abnormal.

[0034] Further, in the torque detection device of the present invention, the first rotating body has a first target in which magnetic poles having different polarities are alternately arranged in the circumferential direction, and the second rotating body has a polarity in the circumferential direction. The second target has a second target in which different magnetic poles are alternately arranged, the first magnetic sensing element is disposed opposite to the magnetic pole of the first target, and the second magnetic is disposed opposite to the magnetic pole of the second target. A detection element; a failure detection magnetic detection element provided at a position shifted from at least one of the first magnetic detection element and the second magnetic detection element; the first magnetic detection element and the second magnetic detection element; A failure determination unit that determines a failure by comparing at least one of these and an output from the failure detection magnetic sensing element may be used.

[0035] According to such a configuration, it is possible to accurately determine the adhesion of a metal object to the target, the failure of the first detection unit or the second detection unit, and the like.

[0036] The first magnetic sensing element is provided at a position shifted from the center of the peripheral surface of the first target to the input shaft side or the output shaft side in the direction along the shaft portion. The element may be provided at a position shifted to the input shaft side or the output shaft side in the direction along the shaft part from the center of the peripheral surface of the second target.

[0037] According to such a configuration, it is further possible to detect a change in magnetic field due to a plurality of magnetic poles. Therefore, the magnetic field change can be detected with higher accuracy.

[0038] Furthermore, the first magnetic sensing element is provided to be shifted from the center of the peripheral surface of the first target toward the input shaft in the direction along the shaft portion, and the second magnetic sensing element is the second magnetic sensing element. The magnetic sensing element for failure determination is provided with a center of the first target and a center of the second target. A configuration provided between the two may be used.

[0039] According to such a configuration, the failure of the two rotating parts can be further determined by one failure detection magnetic sensing element.

[0040] Further, the first target and the second target may be configured to have a multipolar ring magnet force in which magnetic poles having different polarities are alternately arranged on the outer peripheral surface.

[0041] According to such a configuration, the configuration of the present invention can be realized more easily.

[0042] In addition, a third rotating body that rotates in synchronization with the first rotating body, and a third rotating body that is held by the third rotating body and has magnetic poles having different polarities alternately arranged in the rotation direction of the third rotating body. The target, a third detection unit for detecting the rotation angle of the third rotating body, and a third magnetic sensing element arranged opposite to the magnetic pole of the third target, and the third detection unit includes: The magnetic field change is detected by the third magnetic sensing element, and the failure judgment unit is configured to judge the failure by comparing the magnetic field changes detected by the first magnetic sensing element and the third magnetic sensing element. May be.

[0043] According to such a configuration, it is further possible to detect a failure caused by metal adhering to the third target.

[0044] Further, the rotation angle detection device of the present invention includes the first rotation body and the third rotation body based on the rotation angle difference between the torque detection device of the present invention and the first rotation body and the third rotation body. The absolute angle detection part which detects this absolute rotation angle may be provided.

[0045] According to such a configuration, the absolute rotation angles of the first rotating body and the third rotating body can be detected while further having a failure determination function.

[0046] Further, a fourth rotating body connected to the shaft portion and rotating synchronously with the first rotating body may be provided, and the third rotating body may be configured to rotate by the rotation of the fourth rotating body. Good.

[0047] According to such a configuration, the rotation on the input shaft side without affecting the rotation of the first rotating body can be transmitted to the third rotating body. [0048] As described above, according to the present invention, it is possible to provide a torque detection device and a rotation angle detection device with high detection accuracy.

Brief Description of Drawings

FIG. 1 is a cross-sectional view of a torque detector according to a first embodiment of the present invention.

[FIG. 2] FIG. 2 is a cross-sectional view of the torque detector when the AA cross section in FIG. 1 is viewed in the direction of the arrow.

FIG. 3 is a block diagram showing an electrical configuration of the torque detection device.

[FIG. 4A] FIG. 4A is caused by a magnetic field change with respect to the rotation angle (mechanical angle) of each rotating body when the first rotating body, the second rotating body, or the third rotating body is rotated. FIG. 6 is a diagram illustrating an example of outputs from a first detection unit, a second detection unit, and a third detection unit.

FIG. 4B is a diagram showing a rotation angle (electrical angle) of each rotating body calculated using the signal output shown in FIG. 4A.

FIG. 5A is a diagram showing a characteristic waveform of the rotation angle (electrical angle) of the first rotating body with respect to the absolute rotation angle (mechanical angle) of the fourth rotating body.

FIG. 5B is a diagram showing a characteristic waveform of the rotation angle (electrical angle) of the third rotating body with respect to the absolute rotation angle (mechanical angle) of the fourth rotating body.

[FIG. 5C] FIG. 5C is a diagram showing a characteristic waveform of the rotation angle difference (electrical angle difference) between the first rotation body and the third rotation body with respect to the absolute rotation angle (mechanical angle) of the fourth rotation body. It is.

FIG. 6 is a diagram showing an example of a torque characteristic diagram detected by the torque detector.

FIG. 7A is a diagram showing a rotation angle (electrical angle) of the third rotating body with respect to an absolute rotation angle (mechanical angle) of the fourth rotating body.

FIG. 7B is a diagram showing a rotation angle difference (electrical angle difference) between the first rotating body and the third rotating body with respect to an absolute rotation angle (mechanical angle) of the fourth rotating body.

FIG. 7C is a diagram showing a rotation angle (electrical angle) of the first rotating body with respect to an absolute rotation angle (mechanical angle) of the fourth rotating body.

[FIG. 8] FIG. 8 shows the first to third magnetic sensing elements, the amplifying unit, etc. FIG. 6 is a diagram for explaining a method of suppressing the sensitivity variation of the apparatus and preventing the occurrence of a rotation detection error during operation of the apparatus.

FIG. 9 is a cross-sectional view showing a configuration of a torque detection device according to a second embodiment of the present invention.

FIG. 10 is a cross-sectional view of the same torque detector when the AA cross section in FIG. 9 is viewed in the direction of the arrow.

FIG. 11A is a perspective view schematically showing the arrangement relationship between the first and second magnetic detection elements and the failure detection magnetic detection element in part A of FIG.

FIG. 11B is a side view schematically showing the arrangement relationship between the first and second magnetic detection elements and the failure detection magnetic detection element in part A of FIG.

FIG. 12 is a block diagram showing an electrical configuration of the torque detection device.

FIG. 13 is a diagram showing an outline of another arrangement configuration of the first magnetic detection element, the second magnetic detection element, and the failure determination magnetic detection element.

FIG. 14 is a diagram showing an outline of another arrangement configuration of the first magnetic detection element, the second magnetic detection element, and the failure determination magnetic detection element.

FIG. 15 is a diagram showing an outline of another arrangement configuration of the first magnetic detection element, the second magnetic detection element, and the failure determination magnetic detection element.

FIG. 16 is a diagram showing an outline of another arrangement configuration of the first magnetic detection element, the second magnetic detection element, and the failure determination magnetic detection element.

FIG. 17 is a diagram for explaining a torque detection method using a conventional rotation angle degree sensor.

Explanation of symbols

1, 3 Torque detection device

2 Torsion bar

4 Input shaft

6 Output shaft

8 Shaft

10 First rotating body First detector

Second rotating body

Second detector

First target

Second target

First magnetic sensing element

Second magnetic sensing element

3rd rotating body

Third detector

4th rotating body

3rd target

Third magnetic sensing element

Magnetic detection element for failure determination

Amplifier

CPU (torque detector, normalizer, absolute angle detector) EEPROM (memory)

Output signal line

Characteristic wave

Sine wave signal

Cosine wave signal

Triangular wave signal

, 46, 48 Characteristic waveform

Switch

Signal line for specific position determination

, 52 External device

, 62 Gear wheel

Engagement panel

Code board 63 Sensing element

100 rotation angle sensor

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0052] (First embodiment)

FIG. 1 is a cross-sectional view of the torque detection device 1 according to the first embodiment of the present invention, and FIG. 2 is a cross-sectional view of the torque detection device 1 taken along the line AA in FIG. FIG. 3 is a block diagram showing an electrical configuration of the torque detector 1.

The torque detection device 1 according to the first embodiment of the present invention detects torque generated in the shaft portion 8 that is the same rigid body, in which the input shaft 4 and the output shaft 6 are connected to both ends of the torsion bar 2. It is a device that can do.

As shown in FIGS. 1 to 3, the torque detector 1 is connected to the first rotating body 10 connected to the input shaft 4 side of the shaft portion 8 and to the output shaft 6 side of the shaft portion 8. A second rotor 12, a first detector 11 that detects the rotation angle of the first rotor 10, and a second detector 13 that detects the rotation angle of the second rotor 12. And

The first rotating body 10 has a first target 14 that also has a multipolar ring magnet force in which magnetic poles having different polarities are alternately arranged in the circumferential direction. The second rotating body 12 also has a second target 16 having a multipolar ring magnet force in which magnetic poles having different polarities are alternately arranged in the circumferential direction.

[0056] The number of magnetic poles arranged on each of the first target 14 and the second target 16 is the same. A first magnetic sensing element 18 and a second magnetic sensing element 20 for detecting a change in the magnetic field are arranged at positions facing the respective magnetic poles of the first target 14 and the second target 16. .

In addition, the torque detection device 1 includes a third rotating body 22 that rotates synchronously with the first rotating body 10 and rotates around a rotation axis different from that of the first rotating body 10. Furthermore, the torque detection device 1 includes a third detection unit 23 that detects the rotation angle of the third rotator 22.

The torque detection device 1 further includes a fourth rotating body 24 connected to the input shaft 4 side of the shaft portion 8. The third rotating body 22 is arranged so as to rotate in synchronization with the rotation of the fourth rotating body 24. Each of the third rotating body 22 and the fourth rotating body 24 has a gear, and Rotate with the teeth engaged.

With such a configuration, when the input shaft 4 rotates, the first rotating body 10 and the fourth rotating body 24 rotate. Then, the third rotating body 22 rotates in synchronization with the fourth rotating body 24, and as a result, the third rotating body 22 rotates in synchronization with the first rotating body 10.

[0060] The ratio of the rotational speeds of the third rotating body 22 and the fourth rotating body 24 is determined by the gear ratio. In the present embodiment, the diameter of the fourth rotating body 24 is made larger than the diameter of the third rotating body 22, and the number of gears of the third rotating body 22 is smaller than the number of gears of the fourth rotating body 24. is doing.

Further, the third rotating body 22 has a third target 26 that also has a bar magnet force in which different magnetic poles are arranged at both ends. At a position facing the magnetic pole arranged on the third target 26, a third magnetic sensing element 28 for detecting a change in the magnetic field is arranged. The third target 26 is not limited to a bar magnet, and can be a multipolar ring magnet in which magnetic poles having different polarities are alternately arranged in the circumferential direction.

The first detection unit 11 detects a change in the magnetic field due to the magnetic pole disposed on the first target 14 from the output from the first magnetic detection element 18. Similarly, the second detection unit 13 detects a change in the magnetic field due to the magnetic pole disposed on the second target 16 from the output from the second magnetic sensing element 20. Further, the third detection unit 23 detects a change in the magnetic field due to the magnetic pole disposed on the third target 26 from the output from the third magnetic sensing element 28.

Here, as each of the first detection unit 11, the second detection unit 13, and the third detection unit 23, a magnetoresistive element (also referred to as an MR element) can be used.

As shown in FIG. 3, the detection signals detected by the first detection unit 11, the second detection unit 13, and the third detection unit 23 are amplified to a predetermined amplitude by the amplifier 30. Is done.

[0065] Each amplified signal is processed through an AZD converter in the CPU 32 (microcomputer), and between the CPU 32 and the EEPROM (Electronically Erasable and Programmable Read Only Memory) 34 of the nonvolatile memory. The information is read and written as needed. Then, the CPU 32 that is a torque detection unit detects torque from the rotation angle difference between the first rotating body 10 and the second rotating body 12.

[0066] The CPU 32 also functions as a rotation angle detection unit, and from the outputs of the first detection unit 11, the second detection unit 13, and the third detection unit 23, the first rotary body 10, the second rotation unit 10 Rotating body 12 and The rotation angle (electrical angle) of each of the third rotating bodies 22 is detected.

Furthermore, the CPU 32 also functions as an absolute angle detection unit, and the rotation angle difference (electrical angle difference) between the first rotating body 10 and the third rotating body 22, and the second rotating body 12 and the third rotating body 22. The absolute rotation angles of the first rotating body 10, the second rotating body 12, and the third rotating body 22 can be detected from the rotation angle difference (electrical angle difference) of the rotating body 22. In this case, the torque detection device 1 also functions as a rotation angle detection device.

[0068] Information on the detected torque, rotation angle, and absolute rotation angle is output to the external device 51 via the output signal line 36.

Here, a method for detecting the rotation angles (electrical angles) of the first rotating body 10, the second rotating body 12, and the third rotating body 22 in the torque detection device 1 will be described.

[0070] FIG. 4A shows the change in magnetic field with respect to the rotation angle (mechanical angle) of each rotating body when the first rotating body 10, the second rotating body 12, or the third rotating body 22 is rotated. FIG. 6 is a diagram showing an example of the respective outputs of the first detection unit 11, the second detection unit 13, and the third detection unit 23 that are caused. FIG. 4B is a diagram showing the rotation angle (electrical angle) of each rotating body calculated using the signal output shown in FIG. 4A.

[0071] When a change in the magnetic field of the first to third targets 14, 16, and 26 is detected by the first to third magnetic sensing elements 18, 20, and 28, as shown in FIG. On the other hand, a sine wave signal 38 and a cosine wave signal 40 of one cycle are detected as output signals from the first to third detectors 11, 13, and 23.

[0072] A sine wave signal 38 and a cosine wave signal 40 corresponding to the number of magnetic poles are output for each rotation of the first to third rotating bodies 10, 12, and 22 (rotation angle (mechanical angle) per 360 degrees). Detected as a signal.

[0073] The CPU 32 calculates an arctangent signal based on the sine wave signal 38 and the cosine wave signal 40, and calculates the rotation angle (electrical angle) of each rotating body as shown in FIG. 4B. be able to.

[0074] As shown in FIG. 4B, with respect to one pole of the magnetic pole (one cycle of the sine wave signal 38 and cosine wave signal 40), the triangular wave signal 42 for two cycles corresponds to the rotation angle (electrical angle) of each rotating body. ) Is calculated as a signal indicating. Next, a method for detecting the absolute rotation angles (mechanical angles) of the first rotating body 10, the second rotating body 12, and the third rotating body 22 in the torque detection device 1 will be described.

First, a method for detecting the absolute rotation angles of the first rotating body 10 and the third rotating body 22 will be described.

FIG. 5A is a diagram showing a characteristic waveform 44 of the rotation angle (electrical angle) of the first rotating body 10 with respect to the absolute rotation angle (mechanical angle) of the fourth rotating body 24. FIG. 5B is a diagram showing a characteristic waveform 46 of the rotation angle (electrical angle) of the third rotating body 22 with respect to the absolute rotation angle (mechanical angle) of the fourth rotating body 24. FIG. 5C is a diagram illustrating a characteristic waveform 48 of the rotation angle difference (electrical angle) between the first rotating body 10 and the third rotating body 22 with respect to the absolute rotation angle (mechanical angle) of the fourth rotating body 24. . Here, in FIGS. 5A to 5C, the absolute rotation angle (mechanical angle) of the fourth rotating body 24 is assumed to be 0 to 1800 deg. This corresponds to five rotations of the shaft 8.

When the fourth rotating body 24 rotates, the third rotating body 22 connected to the fourth rotating body 24 by a gear also rotates. Here, if the number of teeth of the gear of the fourth rotating body 24 is a and the number of teeth of the gear of the third rotating body 22 is b, the third rotating body 22 is compared with the fourth rotating body 24. And aZ b times faster.

[0079] If the number of magnetic poles of the first target 14 is c (the number of N poles and the number of S poles is (cZ2), respectively), the first rotating body 10 is rotated during one rotation. The magnetic sensor 18 detects c magnetic field (polarity) changes. Thus, by appropriately selecting the number of gear teeth a and b and the number of magnetic poles c, the number of rotations and the number of magnetic field changes can be set to predetermined numbers.

At this time, the rotation angles (electrical angles) of the first rotating body 10 and the third rotating body 22 with respect to the absolute rotation angle (mechanical angle) of the fourth rotating body 24 are shown in FIG. 5A and FIG. The rotation angle (electrical angle) is as shown in 5B.

[0081] In torque detection device 1, the number of magnetic poles of each of first target 14 and third target 26 and the number of gears of each of third rotating body 22 and fourth rotating body 24 are appropriately selected. Thus, with respect to the absolute rotation angle (mechanical angle) of the fourth rotating body 24, the period of the characteristic waveform (triangular wave) 44 of the rotating angle (electrical angle) of the first rotating body 14 and the third rotating body 22 The rotation angle (electrical angle) of the characteristic waveform (triangular wave) 46 period can be made different.

Accordingly, as shown in FIG. 5C, the absolute rotation angle (mechanical angle) of the fourth rotating body 24 is Thus, the characteristic waveform 48 of the rotation angle difference (electrical angle) between the first rotating body 10 and the third rotating body 22 can be uniquely determined. Therefore, if the rotation angle difference (electrical angle difference) between the first rotating body 10 and the third rotating body 22 is known, the absolute rotation angle (mechanical angle) of the fourth rotating body 24 can be uniquely determined. Can do.

[0083] If the absolute rotation angle (mechanical angle) of the fourth rotating body 24 is known, the absolute rotation angle (mechanical angle) of the first rotating body 10 is calculated from the relationship shown in FIGS. 5A and 5C. be able to. Further, the absolute rotation angle (mechanical angle) of the third rotating body 22 can be calculated from the relationship shown in FIGS. 5B and 5C.

[0084] In the same manner as described above, the relationship of the rotation angle (electrical angle) of the second rotating body 12 to the absolute rotation angle (mechanical angle) of the fourth rotating body 24, the fourth rotation The relationship between the rotation angle (electrical angle) of the third rotating body 22 relative to the absolute rotation angle (mechanical angle) of the body 24, and the rotation angle difference (electrical angle) between the second rotating body 12 and the third rotating body 22 From this, the absolute rotation angle (mechanical angle) of the second rotating body 12 can be calculated.

[0085] Next, a method for calculating the torque applied to the torsion bar 2 using the torque detection device 1 will be described.

[0086] As shown in FIG. 1, when the input shaft 4, the torsion bar 2 and the output shaft 6 (shaft portion 8), which are the same rigid body, rotate, the first rotating body fitted to the input shaft 4 10 rotates.

When the first rotating body 10 rotates, the first target 14 held by the first rotating body 10 rotates and the first target 14 disposed at a position facing the first target 14 rotates. Magnetic detection element 18 of 1 detects a magnetic field change. The change of the magnetic field detected by the first magnetic detection element 18 is detected by the first detection unit 11 and output to the CPU 32 as a detection signal.

Further, the second rotating body 12 fitted to the output shaft 6 is also rotated by the rotation of the shaft portion 8.

When the second rotating body 12 rotates, the second target 16 held by the second rotating body 12 rotates, and the second magnetic body disposed at a position facing the second target 16 is rotated. Detection element 20 detects a magnetic field change. The change in the magnetic field detected by the second magnetic detection element 18 is detected by the second detection unit 13 and output to the CPU 32 as a detection signal.

Further, the third rotating body 22 is also rotated by the rotation of the shaft portion 8. As a result, the third target 26 held by the third rotating body 22 also rotates, and the third magnetic sensing element 28 changes the magnetic field. Is detected. The change in the magnetic field detected by the third magnetic detection element 28 is detected by the third detection unit 23 and output to the CPU 32 as a detection signal.

[0090] Based on the detection signals detected by the first to third detection units 11, 13, and 23, CPU3

2 performs the above-described arithmetic processing and detects the absolute rotation angles (mechanical angles) of the first rotating body 10, the second rotating body 12, and the third rotating body 22.

The CPU 32 can calculate the torque by taking the difference (mechanical angle) of the absolute rotation angle between the first rotating body 10 and the second rotating body 12 and multiplying this by the torsion bar constant.

. An example of torque obtained from this rotational angle difference is shown in FIG.

FIG. 6 is a diagram showing an example of torque characteristics detected by the torque detection device 1, and the first rotating body 10 with respect to the rotation angle (mechanical angle) of the input shaft 4 or the output shaft 6 is shown. A torque characteristic wave 37 obtained from the difference between the absolute rotation angles of the second rotating body 12 and the second rotating body 12 is shown.

[0093] When the absolute rotation angle of the first rotating body 10 is X, the absolute rotation angle of the second rotating body 12 is Y, and the torsion bar constant is T, the torque is {(X)-(Y)} It can be detected based on the relationship of X (T).

Next, a method for detecting the absolute rotation angle of the rotating body with higher accuracy will be described.

FIG. 7A to FIG. 7C are diagrams for explaining a method of performing the absolute rotation angle detection of the rotating body with higher accuracy.

FIG. 7A shows the rotation angle (electrical angle) of the third rotating body 22 relative to the absolute rotation angle (mechanical angle) of the fourth rotating body 24, and FIG. 7B shows the absolute rotation angle of the fourth rotating body 24. FIG. 7C shows the rotation angle difference (electrical angle) of the first rotating body 10 and the third rotating body 22 with respect to the rotation angle (mechanical angle). FIG. 7C shows the absolute rotation angle (mechanical angle) of the fourth rotating body 24. The rotation angle (electrical angle) of the first rotating body 10 is shown.

[0097] The rotation angle detection of the first rotating body 10 and the third rotating body 22 includes mechanical errors, element circuit errors, and the like. Therefore, the detection error (E1) is also included in the rotation angle difference between the first rotating body 10 and the third rotating body 22.

This detection error (E1) also appears as a detection error (E2) when calculating the absolute rotation angle (mechanical angle) of the fourth rotating body 24 as well as the rotation angle differential force. As the rotation detection range becomes wider, the gradient of the characteristic waveform 48 of the rotation angle (mechanical angle) decreases, so the first rotating body 10 and the third rotation The influence of the detection error (El) included in the rotation angle difference of the rolling element 22 on the detection of the absolute rotation angle of the fourth rotating body 24 becomes large.

[0099] Here, if the detection error (E2) of the absolute rotation angle of the fourth rotating body 24 is smaller than the period (W1) of the triangular wave in the rotation angle detection of the first rotating body 10, the rotation angle difference The position of the period (W1) can be determined based on the characteristic waveform 48, but in the case shown in FIGS. 7A to 7C, the detection error (E2) is larger than the period (W1). Therefore, it is difficult to accurately determine the position of the period (W1) of the first rotating body 10. Therefore, it is necessary to narrow the rotation detection range of the characteristic waveform 48 (increase the accuracy) and reduce the detection error (E2).

Therefore, in the case shown in FIGS. 7A to 7C, the detection error (E2) of the rotation angle of the fourth rotating body 24 is larger than the period (W2) of the triangular wave in the detection of the rotation angle of the third rotating body 22. First, the position of the period (W2) of the third rotator 22 is determined from the characteristic waveform 48, and then the rotation angle of the first rotator 10 is determined from the relationship between the characteristic waveform 46 and the characteristic waveform 44. Determine the position of the detection cycle (W1).

Here, as shown in FIG. 7A, the rotation angle detection error (E4) of the fourth rotating body 24 corresponding to the rotation angle detection error (E3) of the third rotating body 22 is Since the rotation detection range of the third detector 23 is narrow (resolution is high) and the gradient of the characteristic waveform 46 is large, the rotation angle detection cycle (W1) of the first rotating body 10 can be made smaller.

[0102] Thus, according to the torque detection device 1, the absolute rotation angle (mechanical angle) of the fourth rotating body calculated based on the relationship of FIG. 7B is used to obtain the characteristics from the characteristic waveform 46 shown in FIG. 7A. The absolute rotation angle (mechanical angle) of the rotating body 3 is calculated, and then the position of the period W1 in the characteristic waveform 44 is determined using the characteristic waveform 46 to determine the absolute rotation angle ( (Mechanical angle) can be detected.

[0103] According to this method, the detection accuracy of the absolute rotation angle (mechanical angle) of the first rotating body 10 without changing the rotation detection range of the characteristic waveform 48 can be increased.

[0104] Next, a method of detecting an abnormality of the torque detection device 1 by constantly comparing the rotation angles of the first rotating body 10 and the second rotating body 12 will be described.

In the torque detection device 1, when the first rotating body 10 rotates, the second rotating body 12 also rotates via the torsion bar 2. Between the input shaft 4 and the output shaft 6, a predetermined torque value is exceeded. If the rotational angle difference between the first rotating body 10 and the second rotating body 12 exceeds a predetermined value, the mechanical error or the element circuit It can be judged as an abnormality. Those skilled in the art can determine the predetermined value empirically or by calculating a predetermined torque value force.

[0106] In the torque detection device 1, when the first rotating body 10 rotates, the first target 14 also rotates. As the first target 14 rotates, the magnetic field also changes, and this magnetic field change is detected by the first detector 11. The first detector 11 outputs a sine wave signal 38 and a cosine wave signal 40 as shown in FIG. 4A in response to this magnetic field change.

[0107] These signals are input to the CPU 32 via the amplifier 30, and the CPU 32 calculates an arctangent signal from the sine wave signal 38 and the cosine wave signal 40, and the first rotation as shown in FIG. 4B. The rotation angle (electrical angle) of the body 10 is calculated.

Similarly, when the second rotating body 12 rotates, the second target 16 also rotates. The magnetic field changes with the rotation of the second target 16, and this magnetic field change is detected by the second detector 13. The second detector 13 outputs a sine wave signal 38 and a cosine wave signal 40 as shown in FIG.

[0109] These signals are input to the CPU 32 via the amplifier 30, and the CPU 32 calculates an arctangent signal from the sine wave signal 38 and the cosine wave signal 40, and the rotation angle (electrical angle) of the second rotating body 12 is calculated. ) Is calculated.

[0110] Further, the CPU 32 calculates the absolute rotation angle of the fourth rotating body 24 from the relationships shown in FIGS.

Difference in rotation angle between first rotating body 10 and second rotating body 12 (electrical angle difference) with respect to (mechanical angle) Force Calculate absolute rotation angle between first rotating body 10 and second rotating body 12 . If the origins of the absolute rotation angles (mechanical angles) of the first rotating body 10 and the second rotating body 12 are matched, the absolute rotation angles of the first rotating body 10 and the second rotating body 12 The difference will be less than or equal to a predetermined value unless there is a particular abnormality.

[0111] The CPU 32 detects the absolute rotation angle difference (mechanical angle) between the first rotating body 10 and the second rotating body 12, and notifies the abnormality when the value exceeds a predetermined value. Generate a signal.

[0112] Next, a method for detecting an abnormality of the apparatus by constantly comparing the absolute rotation angles of the first rotating body 10 and the third rotating body 22 will be described. In the torque detection device 1, when the first rotating body 10 rotates, the fourth rotating body 24 fitted to the first rotating body 10 also rotates. When the first rotating body 10 rotates, the first target 14 also rotates. Here, assuming that c magnetic poles are magnetized on the surface of the first target 14, an output signal as shown in FIG. 4A is output from the first detection unit 11.

[0114] Each time the first rotating body 10 rotates (360 Zc) deg, the sine wave signal 38 and the cosine wave signal 40

It changes by 1 period (180deg in electrical angle). That is, the rotation angle (electrical angle) of the first rotating body 10 every (360 Zc) deg can be obtained.

[0115] Here, if the gear ratio of the gear of the fourth rotating body 24 and the gear of the third rotating body 22 is bZa,

4A and 4B, every time the fourth rotating body 24 rotates (360 X (bZa) Z2) deg, the third detector 23 generates a sine wave signal 38 and a cosine wave signal 40 for a period (electrical). Angle 180deg) A changing signal will be output.

[0116] In FIGS. 5A to C, the rotation angle difference between the first rotating body 10 and the third rotating body 22 is equal to the rotation angle origin, and the gradient of the characteristic waveform 48 and the characteristic waveform 46 is equal to one cycle. Rotation angle ratio ((

360 / c): By correcting with (360 X (bZa) Z2)), the value will be below the specified value as long as there is no abnormality in the device. This specified value can be calculated experimentally.

[0117] The CPU 32 detects a difference in rotational angle difference (electrical angle) between the first rotating body 10 and the third rotating body 22, and when the value exceeds a predetermined value, Generate a notification signal.

[0118] Next, a method for suppressing the variation in sensitivity of the first to third magnetic sensing elements 18, 20, 28, the amplifying unit 30 and the like and preventing the occurrence of a rotation detection error during device operation will be described. Figure 8

FIG. 5 is a diagram for explaining this method.

[0119] In the torque detector 1, when the first rotating body 10 rotates, the first target 14 also rotates.

. As the first target 14 rotates, the magnetic field also changes.

Detected at 1.

[0120] The first detector 11 outputs a sine wave signal 38 and a cosine wave signal 40 as shown in FIG. These signals are input to the CPU 32 via the amplifier 30, and the arc tangent signal is calculated based on the sine wave signal 38 and the cosine wave signal 40 in the CPU 32.

[0121] As shown in Fig. 8, the signal level (S1) of the sine wave signal 38 and the cosine wave are applied. If the signal level (S2) of the signal 40 slightly changes due to sensitivity variations of the first magnetic sensing element 18 and the amplifying unit 30, the accuracy of the calculated arctangent signal decreases. Here, description will be made assuming that the maximum value of the amplitude of the sine wave signal 38 and the cosine wave signal 40 is the signal level.

First, as shown in FIG. 3, when the switch 49 is operated to enter the sensitivity memory mode, the first rotating body 10 and the second rotating body 12 are rotated by at least (360 Zc) deg. The signal levels (sensitivities) of the sine wave signal 38 and the cosine wave signal 40 output from the detection unit 11 of 1 are calculated and stored in the EEPROM 34 which is a nonvolatile memory. Similarly, the signal level of the second detection unit 13 that detects the rotation angle of the second rotating body 12 is stored in the EEPROM 34 that is a non-volatile memory.

[0123] When the normal rotation angle value is calculated, switch 49 is operated to turn off the sensitivity memory mode. The CPU 32 functions as a normal part, and the first detection unit 11 and the second detection unit 13 have a signal level of the output sine wave signal 38 and cosine wave signal 40 and the stored signal level. -Calculate the rotation angle value by calculating the force tangent signal by normalizing it to match.

[0124] Also, in the torque detection device 1, it is possible to suppress variations in sensitivity of elements and the like for the signal output from the third detection unit 23.

In this case, when the switch 49 is operated to enter the sensitivity memory mode, the fourth rotating body 24 is rotated so that the third rotating body 22 rotates by 180 degrees or more. Then, the signal levels (sensitivity) of the sine wave signal 38 and the cosine wave signal 40 shown in FIG. 4A calculated from the third detection unit 23 are calculated and stored in the EEPROM 34 which is a nonvolatile memory.

[0126] Then, in the normal mode, the CPU 32 matches the signal level stored as described above with the signal levels of the sine wave signal 38 and the cosine wave signal 40 output from the third detection unit 23. Normalize and calculate the arc tangent signal to determine the rotation angle value.

This makes it possible to correct a difference in signal level due to variations in sensitivity of the magnetic detection element and the amplification unit 30.

[0128] In FIG. 8, if the maximum value of the output amplitude from each of the first to third detectors 11, 13, and 23 is not within the reference range (S3), the temperature characteristics of the element, etc. Fully out by It is considered that the force did not change. In such a case, the resolution required for calculating the rotation angle may not be obtained.

Therefore, it is possible to prevent erroneous output by confirming using a confirmation unit (not shown) for confirming that the output signal level is within the reference range (S3). This confirmation may be performed by the CPU 32 functioning as a confirmation unit.

[0130] In FIG. 8, instead of the signal level, the values of the amplitude centers (Ol) and (02) of the outputs from the first to third detectors 11, 13, and 23 are used to obtain the normal signal. The value that is actually output using the value stored in the memory by the head part is normalized, and the confirmation part is used to check whether the force is within the reference range. However, erroneous output due to characteristic variations can be prevented.

[0131] Furthermore, when performing computations using the signal level and the center of amplitude, the output is sampled multiple times and the average value is obtained, or the maximum value It is possible to prevent erroneous output with higher accuracy by performing normalization processing and comparison processing with the reference range after taking the average value excluding the minimum value.

[0132] Further, by using the torque detection device 1 in the present embodiment, the signal output values from the first to third detection units 11, 13, and 23 at desired positions of the rotating body, or these signals By storing the absolute rotation angle value calculated from the output in the memory, it is possible to detect the absolute rotation angle of the desired position force. Also, by storing these values without applying torque, the origin for torque detection can be set.

Further, at this time, as shown in FIG. 3, a signal indicating that the position of the rotating body is a desired position can be sent from the external device 52 as an electrical signal, as in the specific position determination signal line 50. For example, a specific position can be specified without performing mechanical operation.

[0134] Furthermore, after an electrical signal for determining a specific position is read a plurality of times, an error check can be performed, or a serial signal or the like can be sent. In this way, even if an incorrect signal is input due to noise or the like, the effect can be eliminated.

It is also possible to designate a specific position using the output signal line 36 without having the specific position determining signal line 50.

[0136] (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 9 is a cross-sectional view of the torque detection device 3 according to the second embodiment of the present invention.

FIG. 0 is an arrow view of the AA section in FIG.

FIG. 11A is a perspective view showing an example of an arrangement relationship between the first and second magnetic detection elements 18 and 20 and the failure detection magnetic detection element 29 in part A of FIG. FIG. 12 is a side view of the same, and FIG. 12 is a block diagram showing an electrical configuration of the torque detector 3.

In the torque detection device 3, the same components as those in the torque detection device 1 described in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0140] The torque detection device 3 differs from the torque detection device 1 in that the torque detection device 3 includes the first detection unit 11, the second detection unit 13, the first target 14, the second target 16, and the like. It is equipped with a failure judgment function that judges the failure of the equipment.

As shown in FIG. 11A, in the torque detector 3, the second target 16 is positioned at a position shifted in the rotational direction of the second rotating body 12 with respect to the second magnetic sensing element 20. A failure detection magnetic sensing element 29 is provided so as to face the magnetic pole arranged in FIG.

The CPU 32 functions as a failure determination unit that determines a failure by comparing the magnetic field change detected from the second magnetic detection element 20 and the magnetic field change detected from the failure detection magnetic detection element 29.

As shown in FIGS. 11A and 11B, in the torque detection device 3, the first magnetic sensing element 18 is located below the center of the peripheral surface of the first target 14 (in the direction along the axis 8). The input shaft is shifted to 4). The second magnetic sensing element 20 is provided so as to be shifted from the center of the peripheral surface of the second target 16 to the upper side (the output shaft 6 side in the direction along the shaft 8).

[0144] Further, as described above, the failure detection magnetic detection element 29 is disposed adjacent to the second magnetic detection element 20 at a position shifted in the rotation direction of the second rotating body 12. .

[0145] Here, the function of the torque detection device 3 determining a device failure will be described.

The CPU 32 is based on the comparison between the magnetic field change detected by the second magnetic detection element and the magnetic field change detected by the failure determination magnetic detection element 29 arranged in the vicinity of the second target 16. ! / Hurry to judge the failure. [0147] For example, when a deposit such as a metal adheres to the second target 16, either the second magnetic detection element 20 or the failure detection magnetic detection element 29 adheres before the other. The magnetic field change of the magnetic pole that is magnetically affected due to the object is detected, while the other detects the magnetic field change of the magnetic pole in the state under the magnetic influence.

That is, if there is no deposit on the second target 16, the second magnetic sensing element 20 and the failure determination magnetic sensing element 29 have a phase difference in accordance with the circumferential angle difference between them. However, when there is an adhering portion or when the second detecting portion 13 is out of order, the phase difference of this characteristic waveform changes or the amplitude changes. The CPU 32 determines a failure by detecting this change.

In the above-described example, the example in which the failure detection magnetic detection element 29 is provided in the vicinity of the second magnetic detection element 20 is shown, but the present invention is not limited to this example. A failure detection magnetic detection element 29 may be provided in the vicinity of the first magnetic detection element 18.

[0150] In this case, the CPU 32 determines the first type based on the comparison between the magnetic field change detected by the first magnetic detection element 18 and the magnetic field change detected by the failure determination magnetic detection element 29. Judgment of adhesion of metal objects to the get 14 or failure of the first detection unit 11 is made.

[0151] In addition, examples of the arrangement configuration of the first magnetic detection element 18, the second magnetic detection element 20, and the failure determination magnetic detection element 29 are shown in FIGS. FIGS. 13 to 16 are schematic views showing other arrangement configurations of the first magnetic detection element 18, the second magnetic detection element 20, and the failure determination magnetic detection element 29, respectively.

First, the failure determination magnetic sensing element 29 in FIG. 13 is arranged on the opposite side of the first target 14 from the side where the first magnetic sensing element 18 is provided.

In addition, in the example shown in FIG. 14, the two failure determination detection elements 29 have the first magnetic detection element 18 and the second target 16 with respect to the first target 14 and the second target 16, respectively. The magnetic sensing element 20 is disposed at a position opposite to the position where it is provided.

Further, in the example shown in FIG. 15, the two failure determination detecting elements 29 are shifted in the rotational direction of the first target 14 with respect to the first magnetic detecting element 18, and the second The magnetic sensing elements 20 are arranged at adjacent positions shifted in the rotation direction of the second target 16. Furthermore, in the example shown in FIG. 16, the first magnetic sensing element 18 is provided shifted downward from the peripheral center of the first target 14, and the second magnetic sensing element 20 is Second target

It is provided so as to be shifted upward from the center of 16 peripheral surfaces.

In this case, if the failure detection magnetic sensing element 29 is provided at a position between the center of the circumferential surface of the first target 14 and the center of the circumferential surface of the second target 16, the first magnetic field is detected. Sensing element 1

A failure can be determined using the 8 and second magnetic detection elements 20 and one failure detection magnetic detection element 29.

[0157] In the torque detection device 3, when making a failure determination, the failure was detected by the first magnetic detection element 18 and the third magnetic detection element 28 without using the failure detection magnetic detection element 29. It is also possible to judge failure by comparing magnetic field changes.

[0158] Since the first rotating body 10 and the third rotating body 22 rotate synchronously, the period of the magnetic field change of the magnetic pole detected by the first magnetic sensing element 18 and the third magnetic sensing element 28 is It is constant. When the rotation cycle of the first rotating body 10 is used as a reference, a certain phase difference is generated due to the difference in the cycle.

[0159] If there is an effect on the change in the magnetic field, this constant phase difference will be abnormal.

By detecting this abnormality 32, it can be determined that a deposit has adhered to the first target 14 or the third target 26 and has failed.

It should be noted that, as the first to third magnetic sensing elements 18, 20, 28 and the failure determination magnetic sensing element 29, magnetic sensing elements having the same performance can be used.

Industrial applicability

[0161] As described above, according to the present invention, since it is possible to provide a special effect that it is possible to provide a torque detection device and a rotation angle detection device with high detection accuracy, it is possible to provide power steering for various types of vehicles. It is useful as a torque detection device and a rotation angle detection device used for the above.

Claims

The scope of the claims

[1] a first rotating body coupled to the input shaft side of the shaft portion to be detected;

A second rotating body connected to the output shaft side of the shaft portion;

A first detector for detecting a rotation angle of the first rotating body;

A second detection unit for detecting a rotation angle of the second rotating body;

A torque detection device comprising: a torque detection unit configured to detect torque from a rotation angle difference between the first rotating body and the second rotating body.

[2] The torque detection device according to claim 1,

A third rotating body that rotates synchronously with the first rotating body;

A third detection unit for detecting a rotation angle of the third rotating body;

An absolute angle detector configured to detect absolute rotation angles of the first rotating body and the third rotating body from a rotation angle difference between the first rotating body and the third rotating body. Features a rotation angle detection device.

[3] The absolute angle detection unit may detect an absolute rotation angle of the second rotating body. The rotational angle difference between the second rotating body and the third rotating body. The rotation angle detection device according to claim.

[4] The first rotating body has a first target in which magnetic poles having different polarities are alternately arranged in a circumferential direction,

The second rotating body has a second target in which magnetic poles having different polarities are alternately arranged in the circumferential direction,

The third rotating body has a third target in which magnetic poles having different polarities are alternately arranged in the circumferential direction,

Each of the first detection unit, the second detection unit, and the third detection unit is configured to detect a magnetic field change of a magnetic pole disposed in each of the first target, the second target, and the third target. The rotation angle detection device according to claim 2, wherein the rotation angle detection device detects the rotation angle.

[5] The first target and the second target have a multipolar ring magnet force in which magnetic poles having different polarities are alternately arranged on the outer peripheral surface, and the third target has a bar magnet force. The rotation angle detection device according to claim 4, wherein:

[6] a first magnetic sensing element disposed opposite to the magnetic pole of the first target;

A second magnetic sensing element disposed opposite to the magnetic pole of the second target;

A third magnetic sensing element disposed opposite to the magnetic pole of the third target, the first detection unit detects a magnetic field change by the first magnetic sensing element, and the second detection unit is 5. The rotation angle detection device according to claim 4, wherein a magnetic field change is detected by the second magnetic sensing element, and the third detection unit detects a magnetic field change by the third magnetic sensing element.

[7] The fourth rotating body is connected to the shaft portion and rotates synchronously with the first rotating body, and the third rotating body rotates by the rotation of the fourth rotating body. The rotation angle detection device according to claim 2.

[8] The method includes an abnormality detection unit that compares the absolute rotation angles of the first rotation unit and the second rotation unit and detects an abnormality when the difference exceeds a predetermined value. The rotation angle detection device according to claim 3.

[9] A memory for storing signal levels of the sine wave signal and the cosine wave signal output from the first detection unit, the second detection unit, and the third detection unit;

The rotation angle detection device according to claim 2, further comprising: a normal part that normalizes the sine wave signal and the cosine wave signal according to the signal level.

[10] Confirmation to confirm whether the signal levels of the sine wave signal and the cosine wave signal output from the first detection unit, the second detection unit, and the third detection unit are within a predetermined value 10. The rotation angle detection device according to claim 9, further comprising a unit.

[11] A memory that stores the amplitude centers of the sine wave signal and the cosine wave signal output from the first detection unit, the second detection unit, and the third detection unit;

3. The rotation angle detection device according to claim 2, further comprising: a normal part that normalizes the sine wave signal and the cosine wave signal according to the amplitude center.

[12] The method includes: a confirmation unit that confirms whether an amplitude center of a signal output from the first detection unit, the second detection unit, and the third detection unit is within a predetermined value. The rotation angle detection device according to claim 11.

[13] The first rotating body has a first target in which magnetic poles having different polarities are alternately arranged in a circumferential direction,

A first magnetic sensing element disposed opposite to the magnetic pole of the first target;

A failure detection magnetic detection element provided at a position shifted from at least one of the first magnetic detection element and the second magnetic detection element;

A failure determination unit that determines a failure by comparing at least one of the first magnetic detection element and the second magnetic detection element and an output from the failure detection magnetic detection element; The torque detection device according to claim 1, wherein:

[14] The first magnetic sensing element is provided at a position shifted to the input shaft side or the output shaft side in the direction along the shaft portion from the center of the peripheral surface of the first target, The second magnetic sensing element is provided at a position shifted from the center of the peripheral surface of the second target to the input shaft side or the output shaft side in a direction along the shaft portion. Item 14. The torque detection device according to Item 13.

[15] The first magnetic sensing element is provided to be shifted to the input shaft side in the direction along the shaft portion from the center of the peripheral surface of the first target,

The second magnetic sensing element is provided shifted from the center of the peripheral surface of the second target toward the output shaft in the direction along the shaft portion;

15. The torque detection device according to claim 14, wherein the failure detection magnetic detection element is provided between a peripheral surface center of the first target and a peripheral surface center of the second target. Out device.

16. The torque detection device according to claim 13, wherein the first target and the second target have a multipolar ring magnet force in which magnetic poles having different polarities are alternately arranged on an outer peripheral surface.

[17] a third rotating body that rotates in synchronization with the first rotating body;

Magnetic poles held by the third rotating body and having different polarities in the rotation direction of the third rotating body A third target arranged alternately,

A third magnetic sensing element disposed opposite to the magnetic pole of the third target, the third detection unit detects a magnetic field change by the third magnetic detection element, the failure determination unit, 14. The torque detection device according to claim 13, wherein a failure is determined by comparing magnetic field changes detected by the first magnetic detection element and the third magnetic detection element.

[18] The torque detection device according to claim 17,

And an absolute angle detector that detects an absolute rotation angle of the first rotating body and the third rotating body from a difference in rotation angle between the first rotating body and the third rotating body. Rotation angle detection device.

[19] The fourth rotating body is connected to the shaft portion and rotates synchronously with the first rotating body, and the third rotating body rotates by the rotation of the fourth rotating body. The rotation angle detection device according to claim 18.