Multi-rotation angle detection device

Abstract

The invention provides a multi-rotation angle detection device which generates a multi-rotation absolute angle detection value of a rotating body rotating around a rotation axis. A multi-rotation angle detection device includes: a segment counter that counts segments in an angle region in which rotation exceeds one time, the segments being divided into one rotation cycle of a rotating body; a precision absolute angle detector that generates an absolute angle detection value for one rotation period of the rotating body; and a calculation device that integrates the outputs thereof and generates a multi-rotation absolute angle detection value. The segment counter includes a power generation sensor, a magnetic field generation source, a sensor element, and a non-volatile memory storing a count value. The magnetic field generation source applies an alternating magnetic field of k cycles (k is an integer of 3 or more) to the axial direction of the magnetic wire every time the rotating body rotates. When the arithmetic device receives the external power supply, the counting value stored in the nonvolatile memory is directly used for integrating the absolute angle detection value of the precise absolute angle detector.

Description

[0001] Related Application

[0002] This application claims priority based on Japanese Patent Application No. 2022-170648 filed on October 25, 2022, and incorporates all the contents of this application herein by reference. Technical Field

[0003] The present invention relates to a multi-rotation angle detection device using a power generation sensor. More specifically, the present invention relates to a device that integrates the count value of a segment counter using a power generation sensor and an angle detection value obtained from an angle detector that can precisely detect the absolute angle of one rotation period to detect the multi-rotation absolute angle exceeding one rotation. Background Art

[0004] A magnetic wire having the giant Barkhausen effect (giant Barkhausen jump) is called a Weigand wire or a pulse wire. The magnetic wire includes a core portion and a skin portion provided so as to surround the core portion. One of the core portion and the skin portion is a soft magnetic (soft magnetic) layer in which the magnetization direction is reversed even in a weak magnetic field, and the other of the core portion and the skin portion is a hard magnetic (hard magnetic) layer in which the magnetization direction is not reversed unless a strong magnetic field is applied. By winding a coil around such a magnetic wire, a power generation sensor can be formed.

[0005] When the hard magnetic layer and the soft magnetic layer are magnetized in the same direction along the axial direction of the wire, if the external magnetic field strength in the direction opposite to the magnetization direction increases and reaches a certain magnetic field strength, the magnetization direction of the soft magnetic layer is reversed. The reversal of the magnetization direction propagates from a certain part of the magnetic wire to the entire wire, and the magnetization direction of the soft magnetic layer is reversed together. At this time, the giant Barkhausen effect appears, and a pulse signal is induced in the coil wound around the magnetic wire. When the above external magnetic field strength further increases and reaches a certain magnetic field strength, the magnetization direction of the hard magnetic layer is reversed.

[0006] In this specification, the magnetic field strength when the magnetization direction of the soft magnetic layer is reversed is called the "operating magnetic field", and the magnetic field strength when the magnetization direction of the hard magnetic layer is reversed is called the "stable magnetic field".

[0007] It has the following characteristics: the output voltage obtained from the coil is constant, independent of the change speed of the input magnetic field (external magnetic field), and has a hysteresis characteristic with respect to the input magnetic field, so jitter and the like do not occur. Therefore, the pulse signal generated from the coil can be used for a position detection device or the like.

[0008] When an alternating magnetic field is applied to a power generation sensor, a total of two pulse signals, a positive pulse signal and a negative pulse signal, are generated in one cycle. A magnet can be used as a source for transmitting the magnetic field, and an alternating magnetic field is applied to the power generation sensor through the relative movement between the magnet and the power generation sensor, and the position is detected by counting the generated pulse signals.

[0009] Since the output from the coil has power, a power generation type sensor (power generation sensor) that does not require external power supply can be formed. That is, without providing external power, the peripheral circuit can also be operated by the output energy of the coil.

[0010] Angle sensors such as absolute encoders inherently cannot detect angles exceeding one rotation. In a powered state, if the movement amount is accumulated, angles exceeding one rotation can be detected, but if the power supply is cut off, information exceeding one rotation will be lost.

[0011] On the other hand, the segment counter using the power generation sensor can continue to count using the output energy of the coil even when the external power supply is cut off, so it can detect multiple rotations exceeding one rotation. However, the segment counter using the power generation sensor usually can only detect a rough angle. Therefore, when precise angle detection is required, such as in the case of motor control, the count value of the segment counter and the angle detection value of a separately provided precise absolute angle detector are integrated to utilize the precise angle detection value (multi-rotation absolute angle detection value) across multiple rotations.

[0012] Patent Document 1 and Patent Document 2 disclose methods and devices for integrating the count value of the segment counter and the angle detection value of the precise absolute angle detector.

[0013] Patent Document 1 uses a segment counter in which three power generation sensors are arranged at positions with a phase difference of 60 degrees each.

[0014] Based only on the output of one power generation sensor, the direction of movement cannot be recognized when the direction of movement changes. Therefore, if multiple power generation sensors are used and the phase difference between the outputs of each power generation sensor is used, the direction of movement can be recognized.

[0015] In order for the power generation sensor to output a pulse voltage, it is necessary to change the magnetization direction of only the soft magnetic layer from a state where the magnetization directions of the hard magnetic layer and the soft magnetic layer of the magnetic wire are the same. In a state where the magnetization directions of the hard magnetic layer and the soft magnetic layer are not the same, even if the magnetization direction of only the soft magnetic layer is reversed, no pulse signal will be generated, or even if a pulse signal is generated, it will be very small.

[0016] When continuously rotating in one direction, there is a timing to reach the stable magnetic field after reaching the operating magnetic field and outputting a pulse voltage and before reaching the operating magnetic field again. However, the pulse voltage is surely generated at the angular position of reaching the operating magnetic field.

[0017] However, in the case of bi-directional rotation, that is, in the case of switching the rotation direction, even when reaching the operating magnetic field, no pulse voltage is output, and sometimes so-called pulse missing occurs. Specifically, if the rotation direction is reversed after reaching the operating magnetic field and outputting a pulse voltage and before reaching the stable magnetic field, then even when reaching the operating magnetic field again, the magnetization directions of the hard magnetic layer and the soft magnetic layer are in a non-consistent state, and thus no pulse voltage is output.

[0018] By arranging a plurality of power generation sensors at positions with different phase differences and using the phase differences of their output pulses, the rotation direction can be identified. However, even if two power generation sensors are used, if pulse missing occurs in one of them, the rotation direction cannot be identified. Therefore, as disclosed in Patent Document 1, it is necessary to use three power generation sensors. In Patent Document 1, further, in order to integrate the count value of the segment counter and the detection value of the precision position detector and correct the offset of the origin position, three power generation sensors are arranged at positions with a phase difference of every 60 degrees.

[0019] However, if a plurality of power generation sensors are used, it will lead to an increase in the size and cost of the position detector.

[0020] Patent Document 2 discloses a segment counter that discriminates the rotation direction by performing signal processing on the pulse signal of one power generation sensor and the output signals of other sensor elements other than this power generation sensor, and performs a counting operation accordingly. In this case, if the above-mentioned pulse missing occurs, problems will also occur when integrating the count value of the segment counter and the detection value of the precision position detector. Therefore, in Patent Document 2, the magnetization state of the magnetic wire of the power generation sensor is monitored, and the value of the segment counter is corrected according to the magnetization state by the amount of the missing pulse voltage. Thereby, synchronization of the count value of the segment counter and the detection value of the precision position detector is achieved, and they are integrated.

[0021] Specifically, in the magnetization state monitor disclosed in Patent Document 2, a gradually increasing current is passed through the coil of the power generation sensor, and the magnetic field generated by the coil is applied to the magnetic wire. Thereby, by observing the voltage generated at both ends of the coil, it is monitored whether the magnetization direction of the magnetic wire is reversed. Thereby, the magnetization state of the magnetic wire can be checked.

[0022] However, in order to discriminate the magnetization direction of the magnetic wire as in Patent Document 2 and correct the count value based on this, complex signal processing is required, and accordingly, it is difficult to miniaturize the device and reduce the cost.

[0023] Prior art documents

[0024] Patent documents

[0025] Patent Document 1: Japanese Patent No. 6226811

[0026] Patent Document 2: Japanese Patent No. 5730809 Summary of the invention

[0027] Technical problem to be solved by the invention

[0028] One embodiment of the present invention provides a multi-rotation angle detection device, which is conducive to the miniaturization and cost reduction of the device.

[0029] More specifically, one embodiment of the present invention provides a multi-rotation angle detection device that can integrate the count value of a segmented counter formed without using multiple power generation sensors and the angle detection value of a precision absolute angle detector to generate a multi-rotation absolute angle detection value without complex signal processing.

[0030] Technical means for solving the technical problem

[0031] One embodiment of the present invention provides a multi-rotation angle detection device that generates multi-rotation absolute angle detection values of a rotating body rotating about a rotation axis. The multi-rotation angle detection device includes: a segment counter that counts segments (typically, equally divides) after one rotation period of the rotating body in an angle region exceeding one rotation of the rotating body according to the rotation of the rotating body and generates a count value; a precision absolute angle detector that operates by power supply from the outside and generates absolute angle detection values within one rotation period of the rotating body with a higher resolution than the segments; and an arithmetic device that operates by power supply from the outside and integrates the count value of the segment counter and the absolute angle detection values of the precision absolute angle detector to generate the multi-rotation absolute angle detection values of the rotating body. The segment counter includes one (only one) power generation sensor, a magnetic field generation source that rotates about the rotation axis together with the rotating body, a sensor element different from the power generation sensor (typically, a sensor element other than the power generation sensor), and a non-volatile memory that stores the count value. The power generation sensor has a magnetic wire exhibiting the Barkhausen effect and a coil wound around the magnetic wire, and generates a pulse voltage by a change in the magnetic field accompanying the rotation of the magnetic field generation source. The magnetic field generation source applies an alternating magnetic field of k cycles (k is an integer of 3 or more) to the axial direction of the magnetic wire every one rotation of the rotating body. The segment counter can operate without receiving power supply from the outside, using the energy of the pulse voltage generated by the power generation sensor, and uses the pulse voltage generated by the power generation sensor and the output signal of the sensor element to identify the rotation direction and rotation position of the rotating body, update the count value, and store it in the non-volatile memory. When receiving power supply from the outside, the arithmetic device directly uses the count value stored in the non-volatile memory (that is, does not perform a correction process for correcting the count value of the segment counter), integrates the count value of the segment counter and the absolute angle detection values of the precision absolute angle detector, and generates the multi-rotation absolute angle detection values of the rotating body.

[0032] According to this structure, an alternating magnetic field with a period of k is applied to the axial direction of the magnetic wire by the magnetic field generating source every time of rotation, so that the power generation sensor generates 2k pulse voltages every time of rotation. Since k≥3, an alternating magnetic field with a period of more than 3 is applied to the magnetic wire every time of rotation, and the magnetic wire generates more than 6 pulse voltages every time of rotation. The segment counter can generate, for example, a count value obtained by counting more than k (for example, k or 2k), that is, more than 3 segments obtained by dividing one rotation period. Even if pulse loss occurs due to the reversal of the rotation direction and thus a counting error occurs, an error of the degree that the same count value is obtained within an angular range of more than one rotation will not occur. Thus, an alternating magnetic field with a period of more than 3 is applied to the magnetic wire every time of rotation, and the magnetic wire generates more than 6 pulse voltages every time of rotation. Thus, in any multi-rotation absolute angle, by using the combination of the count value of the segment counter and the absolute angle detection value of the precise absolute angle detector, a precise multi-rotation absolute angle value can be uniquely obtained. That is, even when the count value of the segment counter contains an error, it is possible to integrate with the angle detection value of the precise absolute angle detector without performing a correction process (that is, directly using the count value) on the count value.

[0033] Thus, by using only one power generation sensor, and without performing the magnetization direction discrimination process of the magnetic wire and the correction / synchronization process based thereon, it is possible to integrate the count value of the segment counter and the angle detection value of the precise absolute angle detector, and generate a precise multi-rotation absolute angle detection value.

[0034] In one embodiment of the present invention, the magnetic field generating source includes k magnets arranged with the same-polarity magnetic poles facing the power generation sensor on a circumference centered on the rotation axis. The magnetic wire of the power generation sensor is arranged parallel to the tangent of the circumference. The power generation sensor has a first magnetic flux conduction sheet and a second magnetic flux conduction sheet that are magnetically coupled to both ends of the magnetic wire, respectively. As the magnetic field generating source rotates, the magnetic poles sequentially approach the first magnetic flux conduction sheet and the second magnetic flux conduction sheet. The power generation sensor generates a negative voltage pulse in a first state where the magnetic flux from the magnetic pole of the magnetic field generating source is conducted through the first magnetic flux conduction sheet, and generates a positive voltage pulse in a second state where the magnetic flux from the magnetic field generating source is conducted through the second magnetic flux conduction sheet.

[0035] In this embodiment, typically, on the circumferential orbit around the rotation axis passed by the same-polarity magnetic poles of the k magnets, no other-polarity magnetic poles are arranged. Therefore, as the rotating body rotates in one direction, the same-polarity magnetic poles sequentially face the power generation sensor, and the first state and the second state are alternately repeated.

[0036] According to this structure, k magnets constituting the magnetic field generating source arrange magnetic poles with the same polarity facing the power generation sensor. For example, consider the following situation: in a set state where the soft magnetic layer and the hard magnetic layer of the magnetic wire are magnetized in the direction from the second magnetic flux conduction sheet toward the first magnetic flux conduction sheet (set state for generating negative pulses), the magnetic field generating source rotates together with the rotating body, and the magnetic pole approaches the first magnetic flux conduction sheet. The magnetic flux from this magnetic pole conducts through the first magnetic flux conduction sheet, so that the magnetization direction of the soft magnetic layer of the magnetic wire is reversed, generating a negative pulse. When this magnetic pole further approaches the first magnetic flux conduction sheet, the magnetization direction of the hard magnetic layer is also reversed, and the magnetic wire becomes a set state for generating positive pulses. When the magnetic field generating source further rotates and this magnetic pole approaches the second magnetic flux conduction sheet, the magnetic flux from this magnetic pole conducts through the second magnetic flux conduction sheet. Thus, the magnetization direction of the soft magnetic layer of the magnetic wire is reversed, generating a positive pulse. When this magnetic pole further approaches the second magnetic flux conduction sheet, the magnetization direction of the hard magnetic layer is also reversed, and the magnetic wire becomes a set state for generating negative pulses. Thus, one magnetic pole passes through the detection area of the power generation sensor, generating 2 pulses.

[0037] In one embodiment of the present invention, the sensor element detects whether the magnetic pole of the magnetic field generating source exists at a position opposite to the central portion of the power generation sensor, and the boundary of the segmentation is the angular position where the magnetic pole is opposite to the central portion of the power generation sensor.

[0038] The boundary of the segmentation refers to the boundary at which the count value of the segmentation counter changes.

[0039] By detecting with the sensor element whether the magnetic pole of the magnetic field generating source is opposite to the central portion of the power generation sensor, the rotational position and the rotational direction can be identified based on the outputs of the sensor element and the power generation sensor.

[0040] In one embodiment of the present invention, the magnetic field generating source includes k magnetic pole pairs in which N poles and S poles are alternately arranged on a circumference centered on the rotation axis.

[0041] For example, as an initial state, consider the following state: In a set state where the soft magnetic layer and the hard magnetic layer of the magnetic wire are magnetized in the direction from the second magnetic flux conduction sheet toward the first magnetic flux conduction sheet (a set state for generating a negative pulse), an S pole faces the central portion of the power generation sensor, and the magnetic fluxes from a pair of N poles on both sides of the S pole reach equilibrium. From this initial state, when the magnetic field generating source rotates slightly together with the rotating body, the magnetic flux from the side end of the first magnetic flux conduction sheet of the magnetic wire toward the side end of the second magnetic flux conduction sheet increases, thereby reaching the operating magnetic field, and the magnetization direction of the soft magnetic layer of the magnetic wire is reversed, generating a negative pulse. When the magnetic field generating source rotates further together with the rotating body, the magnetic flux from the side end of the first magnetic flux conduction sheet of the magnetic wire toward the side end of the second magnetic flux conduction sheet further increases and reaches the stable magnetic field, and the magnetization direction of the hard magnetic layer is also reversed, and the magnetic wire becomes a set state for generating a positive pulse. When the magnetic field generating source rotates further, the magnetic flux from the side end of the second magnetic flux conduction sheet of the magnetic wire toward the side end of the first magnetic flux conduction sheet increases and reaches the operating magnetic field, and the magnetization direction of the soft magnetic layer of the magnetic wire is reversed, generating a positive pulse. When the magnetic field generating source rotates further, the magnetic flux from the side end of the second magnetic flux conduction sheet of the magnetic wire toward the side end of the first magnetic flux conduction sheet further increases and reaches the stable magnetic field, and the magnetization direction of the hard magnetic layer is also reversed, and the magnetic wire becomes a set state for generating a negative pulse. Thus, one magnetic pole pair passes through the detection area of the power generation sensor, thereby generating two pulses.

[0042] In one embodiment of the present invention, the magnetic wire of the power generation sensor is located on a tangent to a circle centered on the rotation axis, and the center of the magnetic wire is located at the tangent point of the tangent.

[0043] In one embodiment of the present invention, the sensor element detects the polarity of the magnetic pole facing the central portion of the power generation sensor, and the boundary of the segmentation is the angular position at which either the N pole or the S pole of the magnetic pole pair faces the central portion of the power generation sensor.

[0044] By detecting the polarity of the magnetic pole facing the central portion of the power generation sensor with the sensor element, the rotational position and the rotational direction can be identified based on the outputs of the sensor element and the power generation sensor.

[0045] The above or other objects, features, and effects of the present invention will become clearer by referring to the accompanying drawings and the description of the embodiments as described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a block diagram for explaining a structural example of a multi-rotation angle detection device according to one embodiment of the present invention.

[0047] Figure 2A is a perspective view for explaining a structural example of a segmentation counter,Figure 2B is its top view. And, Figure 2C is the front view observed along the arrow IIC direction of Figure 2B .

[0048] Figure 3A , Figure 3B and Figure 3C are diagrams for explaining the function of the power generation sensor.

[0049] Figure 3D , Figure 3E and Figure 3F are diagrams for explaining the function of the power generation sensor.

[0050] Figure 4 is a diagram for explaining the counting operation of the segmented counter.

[0051] Figure 5 is a table showing an example of a more detailed counting operation of the segmented counter.

[0052] Figure 6 is a diagram for explaining the influence of pulse loss on the count value.

[0053] Figure 7 shows the relationship between the count value of the segmented counter and the angle detection value of the precision absolute angle detector.

[0054] Figure 8 shows the precision multi-rotation absolute angle detection value after integrating the count value of the segmented counter and the angle detection value of the precision absolute angle detector.

[0055] Figure 9A is a perspective view showing a structural example of the segmented counter according to other embodiments of the present invention, Figure 9B is its top view.

[0056] Figure 10A , Figure 10B and Figure 10C are diagrams for explaining the function of the power generation sensor.

[0057] Figure 10D , Figure 10E and Figure 10F are diagrams for explaining the function of the power generation sensor.

[0058] Figure 11 is a diagram for explaining the counting operation of the segmented counter. Detailed implementation mode

[0059] Figure 1This is a block diagram showing a structural example of a multi-rotation angle detection device according to an embodiment of the present invention. The multi-rotation angle detection device 100 is a device that detects the multi-rotation absolute angle of a rotating shaft 30 (an example of a rotating body) rotating about a rotation axis 33 and generates a detection value thereof, that is, a multi-rotation absolute angle detection value. The multi-rotation absolute angle refers to an absolute angle within an angle region that exceeds one rotation, that is, spans multiple rotations. The multi-rotation angle detection device 100 includes a precision absolute angle detector 1, a segment counter 2, and an arithmetic device 4.

[0060] The precision absolute angle detector 1 is an angle sensor that generates a precise absolute angle detection value within one rotation period of the rotating shaft 30, that is, from 0 degrees to 360 degrees, with a higher resolution than the segment counter 2 described below. The precision absolute angle detector 1 is constituted by, for example, an optical absolute encoder. For example, the precision absolute angle detector 1 is configured to generate an absolute angle detection value within an angle region of one rotation period (0 degrees to 360 degrees) with a resolution of 16 bits (65536 steps).

[0061] Typically, the precision absolute angle detector 1 operates by receiving power supply from an external power source. Specifically, the multi-rotation angle detection device 100 includes a power supply circuit 3 that can be connected to an external power source. When the power supply circuit 3 is connected to an external power source, power is supplied to the precision absolute angle detector 1, and the precision absolute angle detector 1 operates by receiving this power. The precision absolute angle detector 1 inputs a 16-bit absolute angle detection value to the arithmetic device 4 through serial communication, for example.

[0062] The segment counter 2 counts the segments obtained by dividing (equally dividing) one rotation period of the rotating shaft 30 according to the rotation of the rotating shaft 30, and generates a count value representing an angle value in units of segments in an angle region that spans multiple rotations (more than one rotation) of the rotating shaft 30.

[0063] The segment counter 2 includes one (only one) power generation sensor 20, a magnetic field generation source 50 that rotates about the rotation axis 33 together with the rotating shaft 30, a sensor element MS different from the power generation sensor 20 (a non-power generation sensor), a counter circuit 8, and a non-volatile memory 9 that stores the count value. The non-volatile memory 9 can be constituted by FeRAM (ferroelectric random access memory). In the present embodiment, the counter circuit 8 and the non-volatile memory 9 are assembled into a counter memory IC (integrated circuit) 10. The segment counter 2 further includes a signal evaluation circuit 5, a rectification / power supply circuit 6, and a signal processing circuit 7.

[0064] The power generation sensor 20 generates a pulse voltage according to the change in the magnetic field accompanying the rotation of the magnetic field generating source 50. In the present embodiment, the sensor element MS is a magnetic sensor that detects the magnetic field of the magnetic field generating source 50 according to the rotation of the magnetic field generating source 50. An example of the magnetic sensor is a Hall IC. The signal evaluation circuit 5 discriminates the polarity of the pulse voltage generated by the power generation sensor 20, and provides a signal (pulse polarity PP) indicating the result of the polarity discrimination to the signal processing circuit 7. The signal processing circuit 7 converts the signal indicating the result of the polarity discrimination obtained from the signal evaluation circuit 5 into digital data (serial signal), and provides it as polarity discrimination data (pulse polarity PP) to the counter circuit 8. In addition, the signal processing circuit 7 converts the output signal of the sensor element MS into digital data (serial signal), and provides it as magnetic detection data to the counter circuit 8.

[0065] The rectification / power supply circuit 6 rectifies the pulse voltage generated by the power generation sensor 20, converts it into an appropriate voltage, and supplies it to the sensor element MS, the signal evaluation circuit 5, the signal processing circuit 7, and the counter memory IC10 (counter circuit 8 and non-volatile memory 9). Therefore, the sensor element MS, the signal evaluation circuit 5, the signal processing circuit 7, and the counter memory IC10 (counter circuit 8 and non-volatile memory 9) can operate without being supplied with power from an external power source. That is, the segment counter 2 can operate by the power generated by its own power generation even when there is no external power supply. The counter memory IC10 can be supplied with power from the power supply circuit 3 and operate when the power supply circuit 3 is connected to an external power source.

[0066] The counter circuit 8 built into the counter memory IC10 performs a counting operation based on the polarity discrimination data (pulse polarity PP) and the magnetic detection data (MS) provided by the signal processing circuit 7 according to a predetermined counting logic. This counting operation is performed regardless of whether there is a supply of external power from the power supply circuit 3. The count value obtained through this counting operation is stored in the non-volatile memory 9. This count value is saved even without power supply (non-volatile storage). When an external power supply is provided, the counter memory 10 can provide the count value stored in the non-volatile memory 9 to the arithmetic unit 4 through serial communication.

[0067] When the power supply circuit 3 is connected to an external power supply, the arithmetic unit 4 receives power supply from the power supply circuit 3 and operates. When the external power supply is turned on, the arithmetic unit 4 requests the precise absolute angle detection value from the precise absolute angle detector 1 and requests the count value from the non-volatile memory 9. The precise absolute angle detector 1 provides the precise absolute angle detection value to the arithmetic unit 4 through serial communication. The non-volatile memory 9 provides the count value to the arithmetic unit 4 through serial communication. The arithmetic unit 4 integrates the precise absolute angle detection value and the count value, generates a multi-rotation absolute angle detection value, and outputs it. The multi-rotation absolute angle detection value output by the arithmetic unit 4 is provided to, for example, an upper-level controller (not shown) and is used for rotation control of a motor, etc.

[0068] The arithmetic unit 4 directly uses the count value provided from the non-volatile memory 9 and integrates it with the precise absolute angle detection value. That is, the count value used in the integration is the value directly counted in the segment timer 2 during the power-off process, and the arithmetic unit 4 does not perform correction processing related to the error of the count value. Specifically, it does not perform synchronization processing for correcting the error of the count value and obtaining synchronization with the precise absolute angle detection value.

[0069] Figure 2A is a perspective view for explaining a structural example of the segment counter 2, Figure 2B is its top view. In addition, Figure 2C is the front view observed along the Figure 2B arrow IIC direction. The segment counter 2 includes a power generation sensor 20, a magnetic field generation source 50, and a sensor element MS (e.g., a magnetic sensor).

[0070] The power generation sensor 20 is disposed on the first support 31 and is supported by the first support 31. In the present embodiment, the sensor element MS is also mounted on the first support 31.

[0071] The magnetic field generation source 50 is fixed to the second support 32. The second support 32 moves relative to the first support 31. Specifically, the second support 32 is coupled (fixed) to the rotating shaft 30 and rotates around the rotation axis 33 together with the rotating shaft 30. Therefore, the second support 32 can be a part of the rotating body. In contrast, the first support 31 is fixedly disposed and held in a non-rotating state. Thus, the magnetic field generation source 50 rotates around the rotation axis 33 together with the second support 32 and moves relative to the first support 31.

[0072] Typically, the rotating shaft 30 rotates by the driving force of a driving shaft from a motor (not shown). When the motor is driven bidirectionally, the rotating shaft 30 rotates in two directions, counterclockwise (CCW) and clockwise (CW), accordingly. The first support 31 can be a printed wiring board disposed along a plane orthogonal to the rotation axis 33.

[0073] The magnetic field generating source 50 includes k magnets M1, M2, ……, Mk (k is an integer of 3 or more. In this embodiment, k = 3) arranged at positions away from the rotation axis 33. The magnets M1, M2, ……, Mk are fixed to the second support 32 so as to sequentially enter the detection area SR of the power generation sensor 20 by the rotational movement of the second support 32 around the rotation axis 33. The magnets M1, M2, ……, Mk are magnetized in the detection area SR such that the same-polarity magnetic poles n1, n2, ……, nk (N poles in this example) face the power generation sensor 20. The magnetic poles n1, n2, ……, nk move along a circumferential track 51 around the rotation axis 33. The configurations of the power generation sensor 20 and the magnetic field transmitting source 50 are determined such that the circumferential track 51 passes through the detection area SR. The magnetic poles n1, n2, ……, nk are arranged at equal intervals on the circumferential track 51.

[0074] The power generation sensor 20 is mounted on one main surface of the first support 31 (printed wiring board). The power generation sensor 20 includes a magnetic wire FE, a first magnetic flux conduction sheet FL1 and a second magnetic flux conduction sheet FL2 that are magnetically coupled to both end portions of the magnetic wire FE, respectively. Between the first magnetic flux conduction sheet FL1 and the second magnetic flux conduction sheet FL2, a coil SP (induction coil) is wound around the magnetic wire FE. The first magnetic flux conduction sheet FL1 and the second magnetic flux conduction sheet FL2 are formed of soft magnetic body members having substantially the same shape and the same size. More specifically, the first magnetic flux conduction sheet FL1 and the second magnetic flux conduction sheet FL2 are symmetrically formed with respect to a symmetry plane 27 (a virtual plane for explaining the geometric configuration) orthogonal to the axial direction x at the axial center position 25 of the magnetic wire FE (hereinafter referred to as "axial center position 25").

[0075] The magnetic wire FE is configured to exhibit the large Barkhausen effect. Specifically, the magnetic wire FE includes a core portion and a skin portion covering the core portion. One of the core portion and the skin portion is a soft magnetic (Soft) layer (soft magnetic layer) whose magnetization direction is reversed even in a weak magnetic field, and the other of the core portion and the skin portion is a hard magnetic (Hard) layer (hard magnetic layer) whose magnetization direction is not reversed unless a strong magnetic field is applied.

[0076] Each of the magnetic flux conduction sheets FL1 and FL2 has magnetic flux conduction ends 21 and 22 opposite to the detection region SR. The magnetic wire FE sets the axial direction x parallel to the tangent at a point (tangent point) on the circumferential track 51 between the pair of magnetic flux conduction ends 21 and 22, and sets the central position 25 of the axial direction x (hereinafter referred to as "axial center position 25") on the perpendicular line perpendicular to the tangent at the tangent point and is arranged. The coil SP generates a negative voltage pulse in the first state where the magnetic fluxes from the magnetic poles n1, n2,..., nk of the magnets M1, M2,..., Mk are conducted out from the first magnetic flux conduction sheet FL1, and generates a positive voltage pulse in the second state where the magnetic fluxes from the magnetic poles n1, n2,..., nk of the magnets M1, M2,..., Mk are conducted out from the second magnetic flux conduction sheet FL2.

[0077] In the present embodiment, the first magnetic flux conduction sheet FL1 and the second magnetic flux conduction sheet FL2 include: an axially orthogonal portion 41 extending parallel to each other in a direction orthogonal to the axial direction x from both end portions of the magnetic wire FE; and an axially parallel portion 42 extending in a direction approaching each other along the axial direction x from the front end portions of the axially orthogonal portion 41. Both end portions of the magnetic wire FE are respectively fixed to the base end portions of the axially orthogonal portions 41 of the first magnetic flux conduction sheet FL1 and the second magnetic flux conduction sheet FL2. More specifically, a wire arrangement portion 23 is provided at the base end portion of the axially orthogonal portion 41, and the wire arrangement portion 23 is formed with a hole or a groove penetrating in the axial direction x. Both end portions of the magnetic wire FE respectively penetrate the axially orthogonal portions 41 of the first magnetic flux conduction sheet FL1 and the second magnetic flux conduction sheet FL2 in the wire arrangement portion 23, and are fixed to the axially orthogonal portions 41. For example, the magnetic wire FE and the first magnetic flux conduction sheet FL1 and the second magnetic flux conduction sheet FL2 are bonded and fixed to each other by a resin (not shown) disposed in the hole or the groove constituting the wire arrangement portion 23. Thereby, both end portions of the magnetic wire FE are respectively magnetically coupled to the first magnetic flux conduction sheet FL1 and the second magnetic flux conduction sheet FL2.

[0078] The power generation sensor 20 is configured such that the side opposite to the axially parallel portion 42 with respect to the magnetic wire FE is the detection region SR for detecting a magnetic field.

[0079] Each of the magnetic flux conduction sheets FL1 and FL2 made of a soft magnetic body member has an axially orthogonal portion 41 having a substantially rectangular parallelepiped shape, and a substantially rectangular parallelepiped-shaped axially parallel portion 42 connected to the end portion, i.e., the front end portion, on the detection region SR side of the axially orthogonal portion 41. Each of the magnetic flux conduction sheets FL1 and FL2 has an L shape that is bent at a right angle at the joint portion between the axially orthogonal portion 41 and the axially parallel portion 42. The axially parallel portion 42 extends along the axial direction x to cover the magnetic wire 110, that is, to shield between the magnetic wire FE and the detection region SR. The first magnetic flux conduction sheet FL1 and the second magnetic flux conduction sheet FL2 having mutually symmetric shapes extend toward the axial center side of the magnetic wire FE, and their proximal ends 42a face each other with a gap therebetween near the axial center position 25 of the magnetic wire FE. The proximal ends 42a form a plane orthogonal to the axial direction x, and the two planes respectively forming the two proximal ends 42a are parallel to each other and face each other in the axial direction x.

[0080] The axially parallel portions 42 of the first magnetic flux conduction sheet FL1 and the second magnetic flux conduction sheet FL2 form magnetic flux conduction ends 21 and 22, and the magnetic flux conduction ends 21 and 22 form a detection region facing surface facing the detection region SR. The magnetic flux conduction ends 21 and 22 (detection region facing surface) are flat surfaces parallel to the axial direction x. When magnetic poles are arranged in the detection region SR, the magnetic flux conduction ends 21 and 22 (detection region facing surface) guide the magnetic flux from the magnetic poles into the first magnetic flux conduction sheet FL1 and the second magnetic flux conduction sheet FL2.

[0081] The axially parallel portions 42 of the first magnetic flux conduction sheet FL1 and the second magnetic flux conduction sheet FL2 are joined to a wiring pattern (not shown) formed on one main surface of the first support 31 (printed wiring board), whereby the power generation sensor 20 is surface-mounted on the first support 31 (printed wiring board). The power generation sensor 20 is arranged such that the axial direction x of the magnetic wire FE is along the tangent line at a point (tangent point) on the circumference centered on the rotation axis 33, and the axial center position 25 of the magnetic wire FE coincides with the tangent point. The detection region SR of the power generation sensor 20 is located on the side opposite to the magnetic wire FE with respect to the axially parallel portion 42, and in this example, it is the region on the other main surface side of the first support 31 (printed wiring board).

[0082] k magnets M1, M2, ……, Mk that constitute the magnetic pole generation source 50 are arranged such that magnetic poles n1, n2, n3 (N poles in the illustrated example) with the same polarity face the first support 31 (printed wiring board). In this example, the second support 32 is configured as an annular shape surrounding the rotation axis 33. More specifically, the second support 32 is composed of an annular plate-like body, is arranged along a plane orthogonal to the rotation axis 33, and is parallel to the first support 31 (printed wiring board). In the second support 32, the magnets M1, M2, ……, Mk are fixed to the surface of the first support 31 (printed wiring board) that faces the other main surface. The magnets M1, M2, ……, Mk are arranged at equal intervals in the circumferential direction around the rotation axis 33. In the illustrated specific example, three magnets M1, M2, M3 are arranged at an angular interval of 120 degrees around the rotation axis 33. The magnetization direction of each magnet M1, M2, ……, Mk is parallel to the rotation axis 33. Then, the magnets M1, M2, ……, Mk are fixed to the second support 32 such that magnetic poles n1, n2, ……, nk with the same polarity (N poles in the illustrated example) face the first support 31 (printed wiring board). The distance from the rotation axis 33 to the magnets M1, M2, ……, Mk (more specifically, the centers of the magnetic poles n1, n2, ……, nk facing the first support 31) is equal to the distance from the rotation axis 33 to the axial center position 25 of the magnetic wire FE. That is, in a top view along the rotation axis 33, the magnetic wire FE and the magnets M1, M2, ……, Mk are located on a circle with the rotation axis 33 as the central axis and having equal radii, whereby a positional relationship in which they can face each other in a direction parallel to the rotation axis 33 is formed. The second support 32 is preferably a magnetic yoke made of a soft magnetic material.

[0083] By rotating together with the rotating shaft 30 around the rotation axis 33 through the second support 32, the magnetic poles n1, n2, ……, nk move on a circumferential orbit 51 passing through the detection area SR with the rotation axis 33 as the center. The axial direction x of the magnetic wire FE is parallel to the tangent passing through a certain point (tangent point) on the circumferential orbit 51, and the axial center position 25 is located on a perpendicular line (in this example, a perpendicular line parallel to the rotation axis 33) perpendicular to the tangent at the tangent point. In other words, the axial center position 25 of the magnetic wire FE is located at a certain point (tangent point) on a circle with the rotation axis 33 as the center and having the same radius as the circumferential orbit 51, and the magnetic wire FE is along the tangent at the tangent point.

[0084] The distance between the first support 31 and the second support 32 in the direction along the rotation axis 33 is determined to be an appropriate value such that the magnetic poles n1, n2, ……, nk of the magnets M1, M2, ……, Mk can enter the detection area SR of the power generation sensor 20 through the rotation of the second support 32.

[0085] In the printed wiring board constituting the first support 31, a sensor element MS formed of, for example, a magnetic sensor is also mounted on the main surface where the power generation sensor 20 is mounted. In this example, the sensor element MS is disposed at a position substantially opposite to the central position of the axial direction x of the magnetic wire FE. Thus, when the magnetic poles n1, n2, ……, nk face the power generation sensor 20 on the circumferential track 51 between the first magnetic flux conduction sheet FL1 and the second magnetic flux conduction sheet FL2, the sensor element MS detects the magnetic fields from the magnetic poles n1, n2, ……, nk and outputs an identification signal. Thus, the sensor element MS detects whether the magnetic poles n1, n2, ……, nk exist at the position in phase with the central portion of the power generation sensor 20, and outputs an identification signal indicating the detection result. The arrangement of the sensor element MS is not limited to this. Specifically, when any one of the magnetic poles n1, n2, ……, nk faces the central portion of the power generation sensor 20, the sensor element MS may be disposed at a position where it can detect the magnetic field from any one of the magnetic poles n1, n2, ……, nk. More specifically, based on the Figure 2B arrangement, the sensor element MS can be disposed at any one of a plurality of positions at an angular interval of 360 degrees / k around the rotation axis 33 (120 degrees interval when k = 3).

[0086] With this structure, each time the magnetic poles n1, n2, ……, nk of one magnet M1, M2, ……, Mk pass through the detection area SR along the circumferential track 51 by rotating counterclockwise CCW around the rotation axis 33, a negative pulse and a positive pulse are sequentially generated. In addition, each time the magnetic poles n1, n2, ……, nk of one magnet M1, M2, ……, Mk pass through the detection area SR along the circumferential track 51 by rotating clockwise CW around the rotation axis 33, a positive pulse and a negative pulse are sequentially generated. Then, the rotation position and the rotation direction can be identified by these pulses and the sensor element MS that outputs an identification signal when the magnets M1, M2, ……, Mk are on the circumferential track 51 between the first magnetic flux conduction sheet FL1 and the second magnetic flux conduction sheet FL2.

[0087] Figures 3A to 3F is a diagram for explaining in detail the operation of the power generation sensor 20. Figure 3A (Initial State: Initial state) shows the first set state as the preparation state for outputting a negative voltage pulse. That is, the magnetization directions of both the soft magnetic layer and the hard magnetic layer of the magnetic wire FE are aligned with the second axial direction x2. In this first set state, as Figure 3B(TriggerNegative: Trigger Negative) As shown, if the magnetic pole n1 of the magnet M1 (N pole in the illustrated example) approaches the magnetic flux conduction end 21 of the first magnetic flux conduction sheet FL1 (the opposite surface of the detection region of the axially parallel portion 42), it is in the first state where the magnetic flux from the magnetic pole n1 is conducted out from the first magnetic flux conduction sheet FL1. Thus, an operating magnetic field in the first axial direction x1 is applied to the magnetic wire FE. As a result, the large Barkhausen effect occurs, and the magnetization direction of the soft magnetic layer is reversed to the first axial direction x1. Subsequently, a negative voltage pulse is generated from the coil SP.

[0088] As Figure 3C (Set: Set (Positive: Positive)) As shown, starting from the first state, if the magnetic pole n1 further approaches the magnetic flux conduction end 21 of the first magnetic flux conduction sheet FL1, the magnetic flux in the first axial direction x1 applied to the magnetic wire FE increases, thereby applying a stable magnetic field, and the magnetization direction of the hard magnetic layer is also reversed to the first axial direction x1. Thus, it is in the second set state where the magnetization directions of both the soft magnetic layer and the hard magnetic layer are aligned with the first axial direction x1. The second set state is the preparation state for generating a positive voltage pulse.

[0089] As Figure 3E (Trigger Positive: Trigger Positive) As shown, starting from the second set state, if the magnet M1 further moves and the magnetic pole n1 approaches the magnetic flux conduction end 22 of the second magnetic flux conduction sheet FL2 (the opposite surface of the detection region of the axially parallel portion 42), it is in the second state where the magnetic flux from the magnetic pole n1 is conducted out from the second magnetic flux conduction sheet FL2. Thus, an operating magnetic field in the second axial direction x2 is applied to the magnetic wire FE. As a result, the large Barkhausen effect occurs, and the magnetization direction of the soft magnetic layer is reversed to the second axial direction x2. Subsequently, a positive voltage pulse is generated from the coil SP.

[0090] As Figure 3F (Set: Set (Negative: Negative)) As shown, starting from the second state, if the magnet M1 further moves and the magnetic pole n1 further approaches the magnetic flux conduction end 22 of the second magnetic flux conduction sheet FL2, the magnetic flux in the second axial direction x2 applied to the magnetic wire FE increases, thereby applying a stable magnetic field, and the magnetization direction of the hard magnetic layer is also reversed to the second axial direction x2. Thus, it returns to the first set state (the preparation state for outputting a negative voltage pulse) where the magnetization directions of both the soft magnetic layer and the hard magnetic layer are aligned with the second axial direction x2.

[0091] When the magnetic pole n1 moves and passes near the power generation sensor 20, the axially parallel portions 42 of the magnetic flux conduction sheets FL1 and FL2 are located between the magnetic pole n1 and the magnetic wire FE, and the axially parallel portions 42 magnetically shield the magnetic wire FE. Therefore, the magnetic flux from the magnetic pole n1 is attracted to the magnetic flux conduction ends 21 and 22 that are the opposite surfaces of the detection region of the axially parallel portion 42, enters the magnetic flux conduction sheets FL1 and FL2 from there, and is guided to the ends of the magnetic wire FE. Thus, a magnetic field in the axial direction x can be applied over almost the entire axial length of the magnetic wire FE. That is, the magnetic flux conduction sheets FL1 and FL2 are configured to have a magnetic field correction function that can correct the magnetic field formed by the magnetic pole n1 at the magnetic flux conduction ends 21 and 22 to the magnetic field in the axial direction x and apply this magnetic field to the magnetic wire FE.

[0092] To achieve this magnetic field correction function, as Figure 3D (Balanced: Balanced) shows, even when the magnetic pole n1 is located at the intermediate position between the pair of magnetic flux conduction sheets FL1 and FL2, there is almost no magnetic flux directly guided from the magnetic pole n1 to the intermediate position in the axial direction of the magnetic wire FE. At this time, the magnetic forces conducted in both the magnetic flux conduction sheets FL1 and FL2 and applied from both ends of the magnetic wire FE reach equilibrium, so that no magnetic field is applied to the magnetic wire FE and the magnetization direction of the magnetic wire FE does not change. Then, when reaching Figure 3E the state, the soft magnetic layer undergoes simultaneous inversion and generates a pulse voltage.

[0093] Figure 4 is a diagram for explaining the operation of the segment counter 2. In the present embodiment, the segment counter 2 counts the segments obtained by dividing (typically, equally dividing) the angular region around the rotation axis 33 into Um (Um is an integer of 3 or more), and generates a count value representing the counting result. Figure 4 shows an example where Um = 3. Three segments are defined by three boundaries a, b, and c set at 120-degree intervals around the rotation axis 33. The boundaries a, b, and c are the boundaries at which the count value of the segment counter 2 switches in response to the voltage pulses generated by the power generation sensor 20. Specifically, the boundary a corresponds to the position where the magnetic pole n1 is opposite to the central portion of the power generation sensor 20, the boundary b corresponds to the position where the magnetic pole n2 is opposite to the central portion of the power generation sensor 20, and the boundary c corresponds to the position where the magnetic pole n3 is opposite to the central portion of the power generation sensor 20. When each of the magnetic poles n1, n2, and n3 crosses the position opposite to the central portion of the power generation sensor 20 and moves counterclockwise (CCW), the count is incremented, and when moving clockwise (CW), the count is decremented.

[0094] The magnetic poles n1, n2, and n3 are arranged at equal intervals in the circumferential direction. Therefore, the intervals between the boundaries a, b, and c are 120° in terms of the rotation angle. If the boundary a is set as the reference angle of 0°, then the boundary b is at the angle of 120°, and the boundary c is at the angle of 240°.

[0095] In this embodiment, the segment counter 2 is designed to count up when the rotation angle moves across the boundaries a, b, and c in the counterclockwise direction CCW, and count down when the rotation angle moves across the boundaries a, b, and c in the clockwise direction CW. Correspondingly, in the following description, the angular value around the rotation axis 33 is based on the boundary a and increases in the counterclockwise direction CCW.

[0096] The magnetic field generating source 50 is configured to generate an alternating magnetic field with k periods (k = 3 in the illustrated example) during one rotation of the rotating shaft 30 around the rotation axis 33. More specifically, in this embodiment, k magnetic poles n1, n2,..., nk are arranged at equal angular intervals around the rotation axis 33.

[0097] The meanings of the symbols in the figure are as follows. "H" is a state value indicating the state where any one of the magnetic poles n1, n2,..., nk is detected by the sensor element MS, that is, the state where any one of the magnetic poles n1, n2,..., nk faces the central part of the power generation sensor 20. "L" is a state value indicating the state where none of the magnetic poles n1, n2,..., nk is detected by the sensor element MS, that is, the state where none of the magnetic poles n1, n2, n3 faces the central part of the power generation sensor 20. These state values correspond to the magnetic detection data generated by the signal processing circuit 7 based on the output of the sensor element MS. "P" is a pulse polarity value indicating the generation of a positive pulse of the power generation sensor 20. "N" is a pulse polarity value indicating the generation of a negative pulse of the power generation sensor 20. These pulse polarity values correspond to the polarity discrimination data generated by the signal processing circuit 7 based on the output of the signal evaluation circuit 5.

[0098] The state value provided from the signal processing circuit 7 to the counter circuit 8 is represented by a combination of these values, updated each time the power generation sensor 20 generates a pulse, and stored in the non-volatile memory 9. "HP" is a state value indicating the state where a positive pulse is generated in the state where any one of the magnetic poles n1, n2,..., nk faces the central part of the power generation sensor 20. "LN" is a state value indicating the state where a negative pulse is generated in the state where none of the magnetic poles faces the central part of the power generation sensor 20. "HN" is a state value indicating the state where a negative pulse is generated in the state where any one of the magnetic poles faces the central part of the power generation sensor 20. "LP" is a state value indicating the state where a positive pulse is generated in the state where none of the magnetic poles faces the central part of the power generation sensor 20.

[0099] "SET_P" represents the angular range that becomes the ready state (set state) for generating a positive pulse. "SET_N" represents the angular range that becomes the ready state (set state) for generating a negative pulse.

[0100] The basic operation of the segment counter 2 is as follows.

[0101] When the rotating shaft 30 rotates counterclockwise (CCW), near the boundaries a, b, and c corresponding to the rotation angles 0°, 120°, and 240° respectively, Figures 3A to 3F through the operation of the power generation sensor 20 shown, a negative pulse and a positive pulse are generated in sequence. At this time, it changes as the state value LN (negative pulse generation) → set state SET_P → state value HP (positive pulse generation) → set state SET_N. The segment counter 2 increments by +1 in the state value HP. That is, when the rotation angle increases through 0° (boundary a), 120° (boundary b), and 240° (boundary c), it increments by +1 respectively.

[0102] When the rotating shaft 30 rotates clockwise (CW), near the boundaries a, b, and c corresponding to the rotation angles 0°, 120°, and 240° respectively, the moving direction of the magnetic pole is Figures 3A to 3F opposite to the operation of the reversed power generation sensor 20. Thus, a positive pulse and a negative pulse are generated in sequence. At this time, it changes as the state value LP (positive pulse generation) → set state SET_N → state value HN (negative pulse generation) → set state SET_P. The segment counter 2 decrements by -1 in the state value HN. That is, when the rotation angle decreases through 0° (boundary a), 120° (boundary b), and 240° (boundary c), it decrements by -1 respectively.

[0103] Figure 5 is a table for illustrating a more detailed counting operation example of the segment counter 2. The counter circuit 8 built into the counter memory IC10 performs the counting operation by following the logic of this table. When the power generation sensor 20 generates a pulse, the state value input from the signal processing circuit 7 to the counter circuit 8 is updated. The counting operation (Count) is determined based on the combination of the updated state value (NEW: new) and the previous state value (OLD: old). The counter circuit 8 reads the previous state value (OLD) from the non-volatile memory 9 and performs the counting operation with it.

[0104] When the updated state value is HP, if the just-previous state value is any one of HN, LP, LN (i.e., if it is other than HP), it becomes a +1 increment counting operation. When the updated state value is HN, if the just-previous state value is any one of HP, LP, LN (i.e., if it is other than HN), a -1 decrement counting operation is performed.

[0105] When the updated status value is LP, it becomes a -1 down-counting operation only when the immediately previous status value is HP. When the updated status value is LN, it becomes a +1 counting operation only when the immediately previous status value is HN. These are exceptional counting operations when the output of the sensor element MS changes from the magnetic pole detection state to the non-magnetic pole detection state and the pulse polarity does not change, and these counting operations are performed for the purpose of compensating for the influence of pulse loss described later.

[0106] Regarding changes in status values other than the above (others), the count value remains unchanged (the change in the count value is "0"). That is, when the current and previous status values are equal, when the current status value is LP and the previous status value is HN or LN, and when the current status value is LN and the previous status value is HP or LP, the count value remains unchanged.

[0107] Thus, the counter circuit 8 identifies the rotation direction and rotation position of the rotating shaft 30 based on the status value, that is, the output signal of the sensor element MS and the pulse voltage generated by the power generation sensor 20, updates the count value, and performs an operation to write this count value into the non-volatile memory 9.

[0108] Figure 6 It is a diagram for explaining the influence of pulse loss on the count value.

[0109] Consider the case where the rotation angle moves along the trajectory T1. When the rotation angle moves counterclockwise CCW across the boundary a and a positive pulse is generated at position 51, it becomes the status value HP (refer to Figure 3E ). If the rotation direction reverses before the rotation angle reaches the position where a stable magnetic field is provided to the magnetic wire FE of the power generation sensor 20 (refer to Figure 3F ), the magnetic wire FE does not become the negative pulse generation ready state (SET_N), and the rotation angle moves across the boundary a in the clockwise direction CW and reaches position 52 where it should become the status value HN. At this time, the negative pulse that should be generated at position 52 is not generated (pulse loss), so the status value is not updated. After that, by further rotating in the clockwise direction CW, the magnetic wire FE becomes the positive pulse generation ready state (SET_P), and when the rotation angle reaches position 53, a negative pulse is generated and it becomes the status value LP. Therefore, if the status value changes as HP→HN, it should be a basic -1 down-counting operation, but in fact the status value changes as HP→LP, so an exceptional -1 down-counting operation is performed (refer to Figure 5 ). Thus, the influence of pulse loss is compensated. The behavior is the same when the rotation direction is opposite, the status value changes as HN→LN, and an exceptional +1 up-counting operation is performed (refer to Figure 5)。Before performing these exceptional counting operations, the count value may contain an error of ±1.

[0110] Next, consider the case where the rotation angle moves along the trajectory T2. That is, the rotation angle moves counterclockwise (CCW) across the boundary b, thereby generating a positive pulse at position 61, becoming the state value HP. If the rotation direction reverses before the rotation angle reaches the position where a stable magnetic field is provided to the magnetic wire FE of the power generation sensor 20 (refer to Figure 3F ), the magnetic wire FE will not enter the negative pulse generation ready state (SET_N), and the rotation angle crosses the boundary b in the clockwise direction (CW) and reaches position 62 where the state value should be HN. At this time, the negative pulse that should be generated at position 62 is not generated (pulse missing), so the state value is not updated. After that, by further rotating in the clockwise direction (CW), the magnetic wire FE enters the positive pulse generation ready state (SET_P). Then, when the rotation direction reverses again, the rotation angle moves counterclockwise (CCW) across the boundary b, and a positive pulse is generated again at position 61, becoming the state value HP. Therefore, if the state value changes according to HP→HN, it should be a basic -1 down counting operation, but in fact the state value changes according to HP→HP, so the count value remains unchanged ( Figure 5 "others"). That is, although the state value changes according to HP→HP, since it is the same position, it is not counted. Thus, in the scenario of trajectory T2, during the period from the generation of the second state value HP to the omission of counting, the count value of the segment counter 2 may contain an error of ±1. The behavior when the rotation direction is opposite is the same, the state value changes according to HN→HN, and the count value remains unchanged (refer to Figure 5 ). In this case, the count value may contain an error of -1. Therefore, before performing the exceptional counting operation, the count value may contain an error of ±1.

[0111] The correct count value within the angular range of one rotation (360 degrees) is "0" in the interval S0 (0 degrees to 120 degrees) between the boundaries a and b, "1" in the interval S1 (120 degrees to 240 degrees) between the boundaries b and c, and "2" in the interval S2 (240 degrees to 360 degrees) between the boundaries b and c. In this case, when considering the counting error as described above, the angular ranges A0, A1, A2 for which the count values may be "0", "1", "2" respectively are as Figure 6 shown. These angular ranges A0, A1, A2 are wider than the angular ranges (120 degrees) of the respective intervals S0, S1, S2, but as Figure 6As shown, they are all less than 1 rotation (360 degrees). Therefore, there is no region that repeats across multiple rotations. Thus, the number of rotations per 1-rotation unit can be determined using the count value and the angle detection value. Specifically, the angle ranges A0, A1, A2 for which the count values may be "0", "1", "2" respectively do not exceed the intervals S2, S1; S0, S2; S1, S0 adjacent to the corresponding intervals S0, S1, S2 respectively.

[0112] In addition, an example of using the counter circuit 8 is shown in this embodiment. The specification of the counter circuit 8 is to provide an alternating magnetic field with k periods to the magnetic wire FE per 1 rotation, and thus when 2k pulses are generated, k counts are performed. In this case, the number of segments Um per 1 rotation is k. However, this is just an example. For example, a counter circuit with the following specification can also be used: 2k counts are performed during the period when 2k pulses are generated per 1 rotation (i.e., +1 or -1 counting is performed according to the pulse generation). In this case, the number of segments Um per 1 rotation is 2k. When the same state value is continuous, the count value is maintained, and a count correction of +2 or -2 is performed for pulse missing. It can also be designed with a number of segments Um other than k or 2k.

[0113] Figure 7 The relationship between the count value of the segment counter 2 and the angle detection value of the precision absolute angle detector 1 is shown. The horizontal axis is the rotation angle (degrees) of the rotation axis 30, and the vertical axis is the multi-rotation absolute angle value, representing 1 rotation (360 degrees) with a resolution of 16 bits (65536 steps). Among them, it is assumed that the number of segments Um = k = 3. As described above, it is not necessarily Um = k. The number of segments Um can be set to any divisor of 2 or more of the number of pulses (2k) generated by the power generation sensor 20 per 1 rotation, preferably a divisor of 3 or more.

[0114] As the rotation axis 30 rotates, the angle detection value of the precision absolute angle detector 1 changes in a sawtooth wave shape between 0 and 65536 as shown by reference numeral 61.

[0115] On the other hand, the count value of the segment counter 2 ideally changes in a stepped manner as shown by reference numeral 62 as the rotation axis 30 rotates. For example, ideally, with 0 degrees as the reference, within each 120-degree (= 360 degrees / 3) range of the angle interval having a central value at intervals of 120 degrees (= 360 degrees / 3), the count value becomes... -3, -2, -1, 0, 1, 2, 3.... The segment counter 2 counts 3 times per 1 rotation, so the step height per 1 count is 65536 / 3.

[0116] Actually, the count value of the segmented counter 2 including the above errors may also be the same value in the error regions e1 and e2 on both sides of each count value. In Patent Document 2, in order to eliminate this error range, magnetic discrimination is performed when the external power supply is turned on, the count value of the segmented counter is corrected, and synchronization is obtained with the angle detection value of the precision absolute angle detector. In the present embodiment, instead of performing such correction and synchronization processing, the count value of the segmented counter 2 including errors is directly used, and the count value of the segmented counter 2 and the angle detection value of the precision absolute angle detector 1 are integrated.

[0117] When specifically explaining, as Figure 7 shown, when the angle detection value of the precision absolute angle detector 1 is a certain value, for example, within the angle range of one rotation (0 degrees to 360 degrees), it is "38299" corresponding to 210 degrees, the count value of the segmented counter 2 is checked. In the angle range across multiple rotations, the angle detection value of the precision absolute angle detection value being "38299" (210 degrees) is a multi-rotation angle with a 360-degree interval based on 210 degrees. That is, it is... -870 degrees, -510 degrees, -150 degrees, 210 degrees, 570 degrees, 930 degrees,.... At these multi-rotation angles, considering the counting error, the possible values of the count value of the segmented counter 2 are as follows in the table.

[0118]

Table 1

[0119] Multiple rotation angles Count value …… …… -870 degrees -8, -7 or -6 -510 degrees -5, -4 or -3 -150 degrees -2, -1 or 0 210 degrees 1, 2 or 3 570 degrees 4, 5 or 6 830 degrees 7, 8 or 9 …… ……

[0120] Even considering the error, the range of possible values for each count value of the segmented counter 2 is less than 360 degrees. Therefore, the same count value does not repeat at different multi-rotation angles. Therefore, using the combination of the count value of the segmented counter 2 and the angle detection value detected by the precision absolute angle detector 1, the multi-rotation absolute angle detection value can be uniquely determined. Therefore, it is not necessary to correct the counting error of the segmented counter 2 and perform processing for synchronizing the count value with the angle detection value detected by the precision absolute angle detector 1. By integrating them, the multi-rotation absolute angle detection value can be generated as Figure 8 shown.

[0121] The arithmetic device 4 uses the count value m of the segmented counter 2 and the angle detection value θ of the precision absolute angle detector 1, and performs operations as follows, for example, and integrates them to calculate the multi-rotation absolute angle detection value θmt. The above Figure 8The operation result is shown. In the following formula, N represents the rotational speed (rotation amount) starting from the reference point (rotation position origin) of the rotation axis 30. Uθ represents the angle detection amount per one rotation (for example, Uθ = 65536 (16 bits)), which is equivalent to the resolution of the precision absolute angle detector 1. Um (for example, Um = k = 3) is the number of segments per one rotation, which is equivalent to the count value of the segment counter 2 per one rotation.

[0122] [Mathematical formula 1]

[0123] θmt = N × U θ + θ

[0124] N = INT(m / U m - θ / U θ + 1 / 2)

[0125] As shown in the above formula, the rotational speed N is obtained by dividing the count value m by the number of segments Um, converting it to the rotational speed, then subtracting the rotation amount (θ / Uθ) corresponding to the angle detection value θ, and then performing rounding. In the example of the above formula, rounding is performed by adding 1 / 2 and using the integerization function INT (a function that discards the decimal part for integerization).

[0126] By multiplying the rotational speed N thus obtained by the angle detection amount Uθ per one rotation, the multi-rotation angle detection value with respect to the count value m of the segment counter 2 can be obtained. By adding the precision angle detection value θ within one rotation, the multi-rotation absolute angle detection value θmt representing the precise multi-rotation absolute angle can be obtained.

[0127] In order to execute part or all of the above operations in the arithmetic unit 4, a previously prepared table can be used as needed.

[0128] In addition, in the actual operation of the rotational speed N, in order to avoid the processing of the value after the decimal point, it is convenient to use the following formula equivalent to the above formula.

[0129] [Mathematical formula 2]

[0130]

[0131] As described above, in the present embodiment, the segmented counter 2 has only one power generation sensor 20 and a sensor element MS, and has a structure in which an alternating magnetic field of 3 cycles or more is applied to the magnetic wire of the power generation sensor 20 per one rotation. The count value of the segmented counter 2 having such a structure can be directly processed including errors and appropriately integrated with the angle detection value generated by the precision absolute angle detector 1, whereby a precise multi-rotation absolute angle detection value can be obtained. Therefore, it is not necessary to use a plurality of power generation sensors 20, nor to discriminate the magnetization direction of the magnetic wire FE of the power generation sensor 20 and the complex correction processing or synchronization processing based thereon. Therefore, the structure can be simplified, and a small-sized, low-cost, and high-resolution multi-rotation precision absolute angle detection device can be provided.

[0132] Figure 9A FIG. is a perspective view for explaining a structural example of the segmented counter 2 applied to the multi-rotation angle detection device according to another embodiment of the present invention. Figure 9B FIG. is a top view thereof. In these figures, the corresponding parts of Figure 2A , Figure 2B and Figure 2C shown are labeled with the same reference numerals.

[0133] In the present embodiment, in the multi-rotation angle detection device 100 having the structure of Figure 1 , the segmented counter 2 having the structure shown in Figure 9A and Figure 9B is used. Compared with the above-described embodiment, the structure of the magnetic field generation source 50 becomes the main difference. In addition, the arrangement of the sensor element MS is also different. The first support body 31 that supports the power generation sensor 20 is changed to support the sensor element MS in a manner that matches the arrangement of the sensor element MS. Further, Figure 9B shows the arrangement of the magnetic field generation source 50 through the first support body 31. The other structure of the segmented counter 2 is the same as that of the above-described embodiment.

[0134] In this embodiment, the magnetic field generating source 50 is constituted by an annular 6-pole magnetized magnet M that surrounds the rotation axis 33. The magnetization direction is parallel to the rotation axis 33. When viewed from one direction of the rotation axis 33, the 6-pole magnetized magnet M has the following structure: on the circumference centered on the rotation axis 33, k (k is an integer of 3 or more. In the illustrated example, k = 3) magnetic pole pairs (pairs of N poles and S poles) obtained by alternately arranging N poles and S poles are arranged, and it has k N poles n1, n2, ……, nk and k S poles s1, s2, ……, sk. Each of the magnetic poles n1, n2, ……, nk; s1, s2, ……, sk spans an angular region of 360 degrees / 2k (60 degrees in this embodiment) around the rotation axis 33. Therefore, the second support 32 rotates together with the rotating shaft 30, and the magnetic field generating source 50 rotates around the rotation axis 33 accordingly, whereby an alternating magnetic field of k cycles (3 cycles in the illustrated example) is applied to the power generation sensor 20.

[0135] The magnetic wire FE of the power generation sensor 20 is located on the tangent of the circumference centered on the rotation axis 33, and the axial center position 25 of the magnetic wire FE is located at the tangent point of the tangent. The power generation sensor 20 is configured such that when the center of one of the magnetic poles n1, n2, ……, nk; s1, s2, ……, sk that spans an angular region of 360 degrees / 2k (60 degrees in this embodiment) around the rotation axis 33 matches the axial center position 25 of the magnetic wire FE, the magnetic forces conducted from the two magnetic flux conduction sheets FL1 and FL2 reach equilibrium.

[0136] The sensor element MS is configured to be able to detect the polarity of the magnetic pole opposite to the central portion of the power generation sensor 20. The sensor element MS is constituted by a magnetic sensor such as a Hall IC, for example, and outputs an H signal when detecting an S pole (when an N pole is opposite to the central portion of the power generation sensor 20), and outputs an L signal when detecting an N pole (when an S pole is opposite to the central portion of the power generation sensor 20). Thus, the sensor element MS discriminates the polarity of the magnetic pole passing near it, and as a result, discriminates the polarity of the magnetic pole opposite to the central portion of the power generation sensor 20. In this embodiment, the sensor element MS is configured to detect the magnetic pole at a position with a phase difference of 180 degrees around the rotation axis 33 with respect to the power generation sensor 20, that is, at a position symmetric with respect to the rotation axis 33. When k is an odd number (for example, 3), the sensor element MS detects the magnetic pole with a polarity opposite to that of the magnetic pole facing the central portion of the power generation sensor 20. When k is an even number (for example, 4), the sensor element MS detects the magnetic pole with the same polarity as the magnetic pole facing the central portion of the power generation sensor 20. In either case, the sensor element MS can detect the polarity of the magnetic pole opposite to the central portion of the power generation sensor 20.

[0137] Figures 10A to 10FAn operation example is shown. Consider the case where the rotating shaft 30 rotates counterclockwise CCW (counterclockwise direction) about the rotation axis 33. Figure 10A is a front view obtained by observing Figure 9B in the direction of arrow X. Figures 10B to 10F It is also a front view observed from the same perspective.

[0138] When reaching Figure 10A ( Figure 9B ) state, the hard magnetic layer and the soft magnetic layer of the magnetic wire FE are magnetized in the direction from the second magnetic flux conduction sheet FL2 toward the first magnetic flux conduction sheet 1, that is, the set state (SET_N) for generating a negative pulse. At this time, the areas of the first magnetic flux conduction sheet FL1 facing the N pole and the S pole are balanced with the areas of the second magnetic flux conduction sheet FL2 facing the N pole and the S pole. In other words, the magnetic field generating source 50, the power generation sensor 20, and their relative configurations are designed to reach this state.

[0139] When the magnetic field generating source 50 rotates slightly counterclockwise CCW together with the rotating shaft 30 from this state, as Figure 10B shown, the ratio of the area of the first magnetic flux conduction sheet FL1 facing the N pole increases, and the ratio of the second magnetic flux conduction sheet FL2 facing the N pole decreases. As a result, a magnetic field in the direction from the first magnetic flux conduction sheet FL1 toward the second magnetic flux conduction sheet FL2 is applied to the magnetic wire FE. When the intensity of this magnetic field reaches the operating magnetic field, the magnetization direction of the soft magnetic layer is reversed, generating a negative voltage pulse. At this time, the sensor element MS detects the N pole (the S pole is opposite to the central part of the power generation sensor 20), so an L signal is generated. Thus, the state value LN is obtained.

[0140] In addition, when the rotating shaft 30 rotates counterclockwise CCW, the magnetic field in the direction from the first magnetic flux conduction sheet FL1 toward the second magnetic flux conduction sheet FL2 becomes stronger and reaches a stable magnetic field. As Figure 10C shown, the magnetization direction of the hard magnetic layer of the magnetic wire FE is also reversed, becoming the set state (SET_P) for generating a positive pulse.

[0141] When the rotating shaft 30 rotates further and reaches from Figure 10C the state to the state after rotating 60 degrees counterclockwise CCW to Figure 10D the state, the polarity is reversed, but the operation is the same as in the above case. That is, the hard magnetic layer and the soft magnetic layer of the magnetic wire FE are magnetized in the direction from the first magnetic flux conduction sheet FL1 toward the second magnetic flux conduction sheet FL2, that is, the set state (SET_P) for generating a positive pulse. At this time, the areas of the first magnetic flux conduction sheet FL1 facing the N pole and the S pole are balanced with the areas of the second magnetic flux conduction sheet FL2 facing the N pole and the S pole.

[0142] When the magnetic field generation source 50 rotates slightly counterclockwise CCW together with the rotation axis 30 from this state, as Figure 10E shown, the ratio of the area of the first magnetic flux conduction sheet FL1 facing the N pole decreases, and the ratio of the second magnetic flux conduction sheet FL2 facing the N pole increases. Thereby, the magnetic field in the direction from the second magnetic flux conduction sheet FL2 toward the first magnetic flux conduction sheet FL1 is applied to the magnetic wire FE. When the intensity of this magnetic field reaches the operating magnetic field, the magnetization direction of the soft magnetic layer is reversed, generating a positive voltage pulse. At this time, the sensor element MS detects the S pole (the N pole is opposite to the central portion of the power generation sensor 20), so an H signal is generated. Thereby, the state value HP is obtained.

[0143] In addition, when the rotation axis 30 rotates counterclockwise CCW, the magnetic field in the direction from the second magnetic flux conduction sheet FL2 toward the first magnetic flux conduction sheet FL1 further strengthens to reach a stable magnetic field, as Figure 10F shown, and the magnetization direction of the hard magnetic layer of the magnetic wire FE is also reversed, becoming a set state (SET_N) for generating a negative pulse. When the rotation axis 30 further rotates 60 degrees counterclockwise CCW from this state, it becomes the same state as Figure 10A equivalent.

[0144] Thereby, one magnetic pole pair passes through the detection area of the power generation sensor 20, generating two pulses. The magnetic field generation source 50 has k (3 in this example) magnetic pole pairs, so 2k (6 in this example) pulses are generated per one rotation.

[0145] By conducting the same examination for rotation in the clockwise direction CW, it can be known that the operation of the segment counter 2 becomes Figure 11 like that. Compared with Figure 4 , the angular positions of the state values LN and LP are different, but the counting method shown in Figure 5 can be directly applied, and the same counting operation as in the above-described embodiment is performed. Thereby, by performing the same signal processing as in the above-described embodiment, the count value of the segment counter 2 and the angle detection value of the precision absolute angle detector 1 can be integrated, and a precision multi-rotation absolute angle detection value can be generated. The boundaries a, b, c of the segments, that is, the boundaries at which the count value switches, correspond to the angular positions at which either the N pole or the S pole of the magnetic pole pair faces the central portion of the power generation sensor 20.

[0146] The above has described the embodiments of the present invention. However, as exemplified below, the present invention can also be implemented in other ways.

[0147] In the above-described embodiments, an example of the power generation sensor 20 using the L-shaped magnetic flux conduction sheets FL1 and FL2 is shown, but the magnetic flux conduction sheets may have other configurations. For example, an I-shaped magnetic flux conduction sheet that extends linearly from the magnetic wire FE toward the detection area may be used. In addition, a structure may be adopted in which cylindrical magnetic flux conduction sheets having a coil size are provided at both ends of the magnetic wire.

[0148] In the above-described embodiments, it is mainly described that the magnetic field generation source 50 has three magnets (refer to Figure 2A ) or three magnetic pole pairs (refer to Figure 9A ), but it may also be configured to have four or more magnets or four or more magnetic pole pairs, and include a segment counter having four or more segments.

[0149] In addition, the precision absolute angle detector 1 does not necessarily mean a single detector, as long as it has the function of obtaining the absolute angle within one rotation. For example, the precision absolute angle detector 1 may be constituted by a plurality of detectors having a detection range of less than one rotation. As an example, the angle of one cycle / rotation may also be obtained by calculation based on the detection signals of a detector of 32 cycles / rotation and a detector of 31 cycles / rotation. In addition, the calculation at this time is also performed by the arithmetic unit 4.

[0150] Although the embodiments of the present invention have been described in detail, these are merely specific examples for clarifying the technical content of the present invention, and the present invention should not be construed as being limited to these specific examples. The scope of the present invention is only defined by the appended claims.

[0151] Reference Numerals

[0152] 1 Precision absolute angle detector

[0153] 2 Segment counter

[0154] 3 Power supply circuit

[0155] 4 Arithmetic unit

[0156] 5 Signal evaluation circuit

[0157] 6 Rectification / power supply circuit

[0158] 7 Signal processing circuit

[0159] 8 Counter circuit

[0160] 9 Non-volatile memory

[0161] 10 Counter memory IC

[0162] 20 Power generation sensor

[0163] 30 Rotation axis

[0164] 31 First support

[0165] 32 Second support

[0166] 33 Axis of rotation

[0167] 50 Magnetic field generating source

[0168] 100 Multi-rotation angle detection device

[0169] FE Magnetic wire

[0170] FL1 First magnetic flux conduction sheet

[0171] FL1 Second magnetic flux conduction sheet

[0172] M 6-pole magnetized magnet

[0173] M1, M2, M3 Magnets

[0174] MS Sensor element

[0175] SP Coil

[0176] SR Detection area

[0177] n1, n2, n3 North poles

[0178] s1, s2, s3 South poles.

Claims

1. A multi-rotation angle detection device, generating multi-rotation absolute angle detection values of a rotating body rotating about a rotation axis, characterized in that, it includes: A segmented counter that, according to the rotation of the rotating body, counts the segments after dividing one rotation period of the rotating body in an angle region exceeding one rotation of the rotating body and generates a count value; A precision absolute angle detector that operates by power supply from the outside and generates absolute angle detection values within one rotation period of the rotating body with a higher resolution than the segments; and An arithmetic device that operates by power supply from the outside, integrates the count value of the segmented counter and the absolute angle detection value of the precision absolute angle detector to generate the multi-rotation absolute angle detection value of the rotating body, The segmented counter includes a power generation sensor, a magnetic field generation source that rotates about the rotation axis together with the rotating body, a sensor element different from the power generation sensor, and a non-volatile memory that stores the count value, The power generation sensor has a magnetic wire showing the Barkhausen effect and a coil wound around the magnetic wire, and generates a pulse voltage through the change of the magnetic field accompanying the rotation of the magnetic field generation source, The magnetic field generation source applies an alternating magnetic field of k cycles (k is an integer of 3 or more) to the axial direction of the magnetic wire every one rotation of the rotating body, The segmented counter can operate without receiving power supply from the outside, using the energy of the pulse voltage generated by the power generation sensor, and uses the pulse voltage generated by the power generation sensor and the output signal of the sensor element to identify the rotation direction and rotation position of the rotating body, update the count value and store it in the non-volatile memory, When receiving power supply from the outside, the arithmetic device directly uses the count value stored in the non-volatile memory, integrates the count value of the segmented counter and the absolute angle detection value of the precision absolute angle detector, and generates the multi-rotation absolute angle detection value of the rotating body.

2. The multi-rotation angle detection device according to claim 1, characterized in that, The magnetic field generation source includes k magnets arranged with the same-polarity magnetic poles facing the power generation sensor on a circumference centered on the rotation axis, The magnetic wire of the power generation sensor is arranged parallel to the tangent of the circumference, The power generation sensor has a first magnetic flux conduction sheet and a second magnetic flux conduction sheet that are magnetically coupled to both ends of the magnetic wire respectively, As the magnetic field generation source rotates, the magnetic poles sequentially approach the first magnetic flux conduction sheet and the second magnetic flux conduction sheet, The power generation sensor generates a negative voltage pulse in a first state where the magnetic flux from the magnetic pole of the magnetic field generation source is electromotive from the first magnetic flux conduction sheet, and generates a positive voltage pulse in a second state where the magnetic flux from the magnetic field generation source is conducted from the second magnetic flux conduction sheet.

3. The multi-rotation angle detection device according to claim 1 or 2, characterized in that, The sensor element detects whether a magnetic pole of the magnetic field generating source exists at a position opposite to the central portion of the power generation sensor, and the boundary of the segmentation is the angular position at which the magnetic pole is opposite to the central portion of the power generation sensor.

4. The multi-rotation angle detection device according to claim 1, wherein, the magnetic field generating source includes k magnetic pole pairs in which N poles and S poles are alternately arranged on a circumference centered on the rotation axis.

5. The multi-rotation angle detection device according to claim 4, wherein, the magnetic wire of the power generation sensor is located on a tangent to the circumference centered on the rotation axis, and the center of the magnetic wire is located at the tangent point of the tangent.

6. The multi-rotation angle detection device according to claim 4 or 5, wherein, the sensor element detects the polarity of the magnetic pole opposite to the central portion of the power generation sensor, and the boundary of the segmentation is the angular position at which either the N pole or the S pole of the magnetic pole pair is opposite to the central portion of the power generation sensor.

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