Multi-rotation angle detecting device and segmented counter for the same

Abstract

The present application relates to a multi-rotation angle detecting device. The device includes a segment counter that counts segments obtained by dividing one rotation cycle of a rotating shaft in an angle region exceeding one rotation of the rotating shaft; a fine absolute angle detector that generates an absolute angle detection value within one rotation cycle of the rotating shaft; and an arithmetic device that integrates outputs of the segment counter and the fine absolute angle detector to generate a multi-rotation absolute angle detection value. The segment counter includes a power generation sensor, a magnetic field generating source, a sensor element, and a nonvolatile memory that stores a count value. The magnetic field generating source applies an alternating magnetic field of two or more cycles to an axial direction of the magnetic wire each time the rotating shaft rotates. The arithmetic device directly uses the count value stored in the nonvolatile memory to integrate the absolute angle detection value of the fine absolute angle detector when receiving a power supply from an external source.

Description

[0001] Related applications

[0002] This application claims priority to Japanese Patent Application No. 2022-170648, filed on October 25, 2022, and Japanese Patent Application No. 2023-010486, filed on January 26, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a device for detecting multiple rotation angles using a power-generating sensor. More specifically, this invention relates to a device for detecting multiple absolute rotation angles exceeding one rotation by integrating the count value of a segmented counter using a power-generating sensor with an angle detection value obtained from an angle detector that precisely detects the absolute angle of one rotation cycle. Furthermore, this invention relates to a segmented counter for use in a device for detecting multiple rotation angles. Background Technology

[0004] Magnetic wires exhibiting the Big Backhausen effect (Big Backhausen jump) are called Wiegand wires or pulse wires. These magnetic wires consist of a core and a skin portion surrounding the core. One of the core and the skin portion is a soft magnetic layer whose magnetization direction reverses even under a weak magnetic field, while the other is a hard magnetic layer whose magnetization direction does not reverse unless a strong magnetic field is applied. By winding a coil around such a magnetic wire, a power generation sensor can be constructed.

[0005] When the hard magnetic layer and the soft magnetic layer are magnetized in the same direction along the axis of the conductor, if the strength of an external magnetic field in the opposite direction to their magnetization direction increases and reaches a certain strength, the magnetization direction of the soft magnetic layer reverses. This reversal of magnetization direction propagates from a portion of the magnetic conductor as a starting point to the entire conductor, and the magnetization direction of the soft magnetic layer reverses simultaneously. At this time, the Big Barkhausen effect occurs, inducing a pulse signal in the coil wound on the magnetic conductor. When the strength of the external magnetic field increases further and reaches a certain strength, the magnetization direction of the hard magnetic layer reverses.

[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] The output voltage obtained from the coil is constant regardless of the rate of change of the input magnetic field (external magnetic field), and it exhibits a hysteresis characteristic with respect to the input magnetic field, thus possessing characteristics such as no jitter. Therefore, the pulse signal generated from the coil is used in position detection devices, etc.

[0008] When an alternating magnetic field is applied to the power generation sensor, one positive pulse signal and one negative pulse signal, a total of two pulse signals, are generated for one cycle. A magnet can be used as a source of the magnetic field, the alternating magnetic field is applied to the power generation sensor by 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 electric power, a power generation type sensor (power generation sensor) that does not require an external power supply can be configured. That is, in the absence of an external power supply, the peripheral circuit can also be made to operate by the output energy of the coil.

[0010] An angle sensor such as an absolute encoder cannot detect an angle exceeding one rotation in principle. If the amount of movement is accumulated in a state in which power is supplied, an angle exceeding one rotation can be detected, but if the power is cut off, information on an angle exceeding one rotation is lost.

[0011] On the other hand, a segmented counter using a power generation sensor can continue counting using the output energy of the coil even in a state in which the external power supply is cut off, and can thus detect a plurality of rotations exceeding one rotation. However, a segmented counter using a power generation sensor in general can only detect a rough angle. Therefore, in a case in which precise angle detection is required, such as in a case of use for motor control, the count value of the segmented counter is integrated with an angle detection value of a precise absolute angle detector provided separately, and a precise angle detection value (a plurality-of-rotation absolute angle detection value) encompassed by a plurality of rotations is used.

[0012] Patent Document 1 and Patent Document 2 disclose a method and a device that integrate the count value of the segmented counter and the angle detection value of the precise absolute angle detector.

[0013] Patent Document 1 uses a segmented counter in which three power generation sensors are arranged at positions at which the phase difference is 60 degrees from each other.

[0014] With only the output of one power generation sensor, the direction of movement cannot be identified when the direction of movement is changed. Therefore, if a plurality of power generation sensors is used and the phase difference between the outputs of the respective power generation sensors is used, the direction of movement can be identified.

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

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

[0017] However, in the case of bidirectional rotation, that is, in the case of switching the rotation direction, even if the operation magnetic field is reached, the pulse voltage is not output, and sometimes so-called pulse omission occurs. Specifically, if the rotation direction is reversed after reaching the operation magnetic field and outputting the pulse voltage, before reaching the stable magnetic field, even if the operation magnetic field is reached again, the magnetization directions of the hard magnetic layer and the soft magnetic layer are in a state of disagreement, and therefore the pulse voltage is not output.

[0018] By configuring a plurality of power generation sensors at positions different in phase difference, and using the phase difference of the output pulses thereof, it is possible to identify the rotation direction. However, even if 2 power generation sensors are used, if one of them generates pulse omission, it is not possible to identify the rotation direction. Therefore, as disclosed in Patent Literature 1, it is necessary to use 3 power generation sensors. In Patent Literature 1, in order to integrate the count value of the segment counter and the detection value of the precision position detector, and to correct the shift of the origin position, the 3 power generation sensors are further configured at positions at which the phase difference is 60 degrees from each other.

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

[0020] Patent Literature 2 discloses a segment counter that discriminates the rotation direction by signal processing the pulse signal of one power generation sensor, and the output signal of another sensor element other than the power generation sensor, and performs a counting operation accordingly. In this case, if the above-described pulse omission occurs, it is inconvenient when integrating the count value of the segment counter and the detection value of the precision position detector. Therefore, in Patent Literature 2, the magnetization state of the magnetic wire of the power generation sensor is monitored, and the value of the segment counter corresponding to the omitted pulse voltage is corrected on the basis of the magnetization state. Thereby, the count value of the segment counter and the detection value of the precision position detector are synchronized, and they are integrated.

[0021] Specifically, in the monitor of the magnetization state disclosed in Patent Literature 2, a gradually increasing current is caused to flow 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 across the coil, it is monitored whether the magnetization direction of the magnetic wire is reversed. Thereby, it is possible to check the magnetization state of the magnetic wire.

[0022] However, in order to perform the magnetization direction discrimination of the magnetic wire and the correction of the count value based thereon as in Patent Literature 2, complicated signal processing is required, and accordingly it is difficult to perform the downsizing and cost reduction of the device.

[0023] Prior Art Documents

[0024] Patent Documents

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

[0026] Patent Document 2: Japanese Patent No. 5730809 SUMMARY

[0027] PROBLEMS TO BE SOLVED BY THE INVENTION

[0028] One embodiment of the present application provides a multi-rotation angle detection device that is advantageous in miniaturization and cost reduction of the device.

[0029] More specifically, one embodiment of the present application provides a multi-rotation angle detection device that can integrate a count value of a segment counter configured without using a plurality of power generation sensors and an angle detection value of a precision absolute angle detector to generate a multi-rotation absolute angle detection value without complicated signal processing.

[0030] Further, one embodiment of the present application provides a segment counter that counts segments by a new algorithm and a multi-rotation angle detection device including the segment counter.

[0031] MEANS FOR SOLVING THE PROBLEMS

[0032] One embodiment of the present application provides a multi-rotation angle detection device and a segment counter having the following features.

[0033] 1. A multi-rotation angle detection device that generates a multi-rotation absolute angle detection value of a rotating body that rotates around a rotation axis, comprising:

[0034] a segment counter that counts segments obtained by dividing one rotation period of the rotating body in an angle region exceeding one rotation of the rotating body according to rotation of the rotating body and generates a count value;

[0035] a precision absolute angle detector that operates by supply of power from the outside and generates an absolute angle detection value within one rotation period of the rotating body at a higher resolution than the segments; and

[0036] an arithmetic device that operates by supply of power from the outside, integrates the count value of the segment counter and the absolute angle detection value of the precision absolute angle detector, and generates a multi-rotation absolute angle detection value of the rotating body,

[0037] The segment counter includes a power generation sensor, a magnetic field generation source that rotates together with the rotating body around the rotation axis, a sensor element that is different from the power generation sensor, and a nonvolatile memory that stores the count value,

[0038] The power generation sensor has a magnetic conductor that exhibits a large Barkhausen effect and a coil that is wound around the magnetic conductor, and generates a pulse voltage by a change in a magnetic field accompanying rotation of the magnetic field generation source,

[0039] The magnetic field generation source applies an alternating magnetic field of two or more periods to the magnetic conductor in the axial direction each time the rotating body rotates,

[0040] The segment counter does not need to receive a power supply from the outside, and operates by the energy of the pulse voltage generated by the power generation sensor, and if the power generation sensor generates a pulse voltage, the rotation direction and the rotation position of the rotating body are identified using the polarity of the pulse voltage (hereinafter referred to as "the polarity of this time's pulse voltage"), the output state of the sensor element at the time of generation of the pulse voltage (hereinafter referred to as "this time's sensor element state"), the polarity of the last pulse voltage, the output state of the sensor element at the time of generation of the last pulse voltage (hereinafter referred to as "the last sensor element state"), and the count value (hereinafter referred to as "the last count value") that is updated and stored in the nonvolatile memory by the generation of the last pulse voltage, the count value is updated and stored in the nonvolatile memory,

[0041] In the segment counter,

[0042] The rotation direction of the rotating body is identified according to the combination of the polarity of this time's pulse voltage and this time's sensor element state, and the sign of the count is decided,

[0043] When the polarity of this time's pulse voltage is different from the polarity of the last pulse voltage, the absolute value of the count is set to 1,

[0044] When the polarity of this time's pulse voltage is the same as the polarity of the last pulse voltage, and this time's sensor element state is the same as the last sensor element state, the absolute value of the count is set to 0,

[0045] When the polarity of this time's pulse voltage is the same as the polarity of the last pulse voltage, and this time's sensor element state is different from the last sensor element state, the absolute value of the count is set to 2,

[0046] The count value is updated by adding the count value obtained by assigning the decided sign to the absolute value of the count to the last count value,

[0047] The operation device integrates the count value of the segment counter and the absolute angle detection value of the precision absolute angle detector using the count value stored in the nonvolatile memory directly when receiving power supply from the outside, and generates a multiple-rotation absolute angle detection value of the rotating body.

[0048] According to this structure, the magnetic field generation source rotates together with the rotating body around the rotation axis, and thus the magnetic field generation source applies an alternating magnetic field of two or more periods in the axial direction of the magnetic wire at each rotation. Thus, the power generation sensor generates four or more pulse voltages at each rotation. Thus, for example, the segment counter can generate a count value obtained by counting segments obtained by dividing one rotation period into four or more. Even if a pulse is missing due to a reversal of the rotation direction, and a count error is generated accordingly, an error to the extent that the same count value is reached in an angle range covering one rotation or more is not generated. Thus, an alternating magnetic field of two or more periods is applied to the magnetic wire at each rotation, and the magnetic wire generates four or more pulse voltages at each rotation, and thus, for an arbitrary multiple-rotation absolute angle, a precise multiple-rotation absolute angle value can be uniquely found by the combination of the count value of the segment counter and the absolute angle detection value of the precision absolute angle detector. That is, even in the case where the count value of the segment counter contains an error, the angle detection value of the precision absolute angle detector can be integrated without correction processing of the count value (i.e., the count value is used directly).

[0049] Thus, only one power generation sensor is used, and without performing the magnetization direction discrimination processing of the magnetic wire and the correction / synchronization processing based thereon, the count value of the segment counter and the angle detection value of the precision absolute angle detector can be integrated, and a precise multiple-rotation absolute angle detection value can be generated.

[0050] In the present embodiment, the segment counter performs a counting operation according to all the pulse voltages generated by the power generation sensor, and operates according to a new algorithm that compensates for a missing pulse. That is, the segment counter recognizes the rotation direction of the rotating body according to the combination of the polarity of the present pulse voltage and the present sensor element state, and determines the sign of the count value.

[0051] When the rotating body rotates in one direction, the polarity of the pulse voltage alternately changes, and thus, if the polarity of the pulse voltage is reversed, there is an angular displacement across segments. Thus, when the polarity of the present pulse voltage is different from the polarity of the last pulse voltage, the segment counter sets the absolute value of the count value to 1.

[0052] Reversal of the rotation direction causes a pulse to be missed, and sometimes the pulse voltages of the same polarity are continuous and the sensor element states also become the same. In this case, it can be considered that the same angular position is returned to, and thus it is appropriate to make the count value unchanged. Therefore, when the polarity of the present pulse voltage is the same as the polarity of the last pulse voltage and the present sensor element state is the same as the last sensor element state, the segment counter sets the absolute value of the count value to 0.

[0053] Further, since the reversal of the rotation direction causes a pulse to be missed, sometimes the pulse voltages of the same polarity are continuous and the sensor element states change. In this case, it can be considered that the movement is made across the boundaries of the segments twice. Therefore, when the polarity of the present pulse voltage is the same as the polarity of the last pulse voltage and the present sensor element state is different from the last sensor element state, the segment counter sets the absolute value of the count value to 2.

[0054] The segment counter obtains the count value by assigning the decided sign to the absolute value of the count value thus obtained, and updates the count value by adding this count value to the last count value.

[0055] Thus, the counting operation can be made in accordance with all the pulse voltages generated by the power generation sensor, and the pulse miss can be compensated for. Since the compensation for the pulse miss is performed in accordance with the generation of the pulse voltage, the count value of the segment counter sometimes contains an error. As described above, even in this case, the count value of the segment counter can be directly used and integrated with the absolute angular detection value.

[0056] 2. The multi-rotation angle detection device according to item 1, wherein, when the power generation sensor generates a pulse voltage, the segment counter saves the polarity of the pulse voltage and the output state of the sensor element at the time of generation of the pulse voltage in the nonvolatile memory.

[0057] Thus, the segment counter can perform the above-described counting operation by obtaining the information of the polarity of the last pulse voltage and the sensor element state from the nonvolatile memory.

[0058] 3. The multi-rotation angle detection device according to item 1 or 2, wherein the segment counter counts segments obtained by dividing one rotation period of the rotating body into four or more.

[0059] With this structure, the segment counter can count four or more segments at each rotation. Typically, the number of segments when the magnetic field generation source applies an alternating magnetic field of k periods (k > 2) to the magnetic conductor wire at each rotation of the rotating body is 2k.

[0060] 4. The multi-rotation angle detecting device according to any one of items 1 to 3, wherein the magnetic field generating source includes two or more pairs of magnetic poles in which N poles and S poles are alternately arranged on a circumference centered on the rotation axis.

[0061] For example, as an initial state, consider a state in which, in a set state in which the soft magnetic layer and the hard magnetic layer of the magnetic wire are magnetized from the 1st end portion of the magnetic wire toward the 2nd end portion (a set state for generating a negative pulse), one S pole opposes the central portion of the power generation sensor, and the magnetic flux from a pair of N poles on both sides of the S pole reaches equilibrium. When the magnetic field generating source is slightly rotated from this initial state together with the rotating body, the magnetic flux from the 1st end portion of the magnetic wire toward the 2nd end portion increases to reach an action magnetic field, the magnetization direction of the soft magnetic layer of the magnetic wire is reversed, and a negative pulse is generated. When the magnetic field generating source is further rotated together with the rotating body, the magnetic flux from the 1st end portion of the magnetic wire toward the 2nd end portion further increases to reach a stable magnetic field, 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 is further rotated, the magnetic flux from the 2nd end portion of the magnetic wire toward the 1st end portion increases to reach an action magnetic field, the magnetization direction of the soft magnetic layer of the magnetic wire is reversed, and a positive pulse is generated. When the magnetic field generating source is further rotated, the magnetic flux from the 2nd end portion of the magnetic wire toward the 1st end portion further increases to reach a stable magnetic field, 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 pair of magnetic poles passes through the detection region of the power generation sensor, and 2 pulses are generated.

[0062] When the magnetic field generating source includes k (k≥2) pairs of magnetic poles in which N poles and S poles are alternately arranged on a circumference centered on the rotation axis, k periods of alternating magnetic fields are applied to the magnetic wire each time the rotating body rotates, and 2k pulses are generated accordingly.

[0063] 5. The multi-rotation angle detecting device according to item 4, wherein the magnetic wire of the power generation sensor is located on a tangent line of the circumference centered on the rotation axis, and the center of the magnetic wire is located on a tangent point of the tangent line.

[0064] With this structure, the magnetic field generating source and the magnetic wire are appropriately magnetically coupled, and alternating magnetic fields can be appropriately applied to the magnetic wire as the rotating body rotates.

[0065] 6. The multi-rotation angle detecting device according to item 5, wherein the power generation sensor has a 1st magnetic flux conducting member and a 2nd magnetic flux conducting member that are magnetically coupled to both end portions of the magnetic wire, respectively.

[0066] In this structure, the first magnetic flux conductor is magnetically coupled to the first end portion of the magnetic wire, and the second magnetic flux conductor is magnetically coupled to the second end portion of the magnetic wire. Thus, the magnetic coupling between the magnetic field generation source and the magnetic wire can be enhanced, and a good pulse voltage can be generated by applying a strong magnetic field in the axial direction of the magnetic wire.

[0067] 7. The multi-revolution angle detection device according to any one of items 4 to 6, wherein the sensor element detects the polarity of the magnetic pole opposite the central portion of the power generation sensor.

[0068] In this case, the boundary of the segment can be the angular position at which either one of the N pole and the S pole of the pole pair opposite the central portion of the power generation sensor. The boundary of the segment is the boundary at which the count value of the segment counter changes.

[0069] 8. A segment counter that counts segments obtained by dividing one rotation period of a rotating body that rotates around a rotation axis, in an angular region exceeding one rotation of the rotating body, and generates a count value, based on the rotation of the rotating body,

[0070] including a power generation sensor, a magnetic field generation source that rotates around the rotation axis together with the rotating body, a sensor element that is different from the power generation sensor, a nonvolatile memory that stores the count value, and a counter circuit that updates the count value,

[0071] the power generation sensor having a magnetic wire that exhibits a large Barkhausen effect and a coil wound around the magnetic wire, and generating a pulse voltage by a change in magnetic field accompanying the rotation of the magnetic field generation source,

[0072] the magnetic field generation source applying an alternating magnetic field of two or more periods to the axial direction of the magnetic wire at each rotation of the rotating body,

[0073] if the power generation sensor generates a pulse voltage, the counter circuit identifies the rotation direction and the rotation position of the rotating body using the polarity of this pulse voltage (hereinafter referred to as "the polarity of this time's pulse voltage"), the output state of the sensor element at the time of generation of this pulse voltage (hereinafter referred to as "the state of this time's sensor element"), the polarity of the last pulse voltage, the output state of the sensor element at the time of generation of the last pulse voltage (hereinafter referred to as "the state of the last time's sensor element"), and the count value (hereinafter referred to as "the last time's count value") that was updated and stored in the nonvolatile memory due to the generation of the last pulse voltage, updates the count value and stores it in the nonvolatile memory,

[0074] in the counter circuit,

[0075] identifying a rotation direction of the rotating body according to a combination of a polarity of the present pulse voltage and the present sensor element state, and deciding a sign of a count number,

[0076] when the polarity of the present pulse voltage is different from the polarity of the last pulse voltage, setting an absolute value of the count number to 1,

[0077] when the polarity of the present pulse voltage is the same as the polarity of the last pulse voltage and the present sensor element state is the same as the last sensor element state, setting an absolute value of the count number to 0,

[0078] when the polarity of the present pulse voltage is the same as the polarity of the last pulse voltage and the present sensor element state is different from the last sensor element state, setting an absolute value of the count number to 2,

[0079] adding the count number obtained by giving the decided sign to the absolute value of the count number to the last count value, thereby updating the count value.

[0080] The above and other objects, features and effects of the present application will become more apparent from the following description of embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF DRAWINGS

[0081] Figure 1 is a block diagram for explaining a configuration example of a multi-rotation angle detection device according to an embodiment of the present application.

[0082] Figure 2A is a perspective view for explaining a configuration example of a segmented counter, Figure 2B is a plan view thereof. Furthermore, Figure 2C is a front view as viewed in the direction of arrow IIC of Figure 2B .

[0083] Figure 3A , Figure 3B and Figure 3C are action explanatory diagrams for explaining an action of a power generation sensor.

[0084] Figure 3D , Figure 3E and Figure 3F are action explanatory diagrams for explaining an action of a power generation sensor.

[0085] Figure 4 is a diagram for explaining a counting action of a segmented counter.

[0086] Figure 5 is a table for explaining an example of a more detailed counting action of a segmented counter.

[0087] Figure 6 is a graph for explaining the influence of the pulse omission on the count value.

[0088] Figure 7 shows the relationship between the count value of the segmented counter and the angle detection value of the precision absolute angle detector.

[0089] Figure 8 shows the relationship between the count value of the segmented counter and the angle detection value of the precision absolute angle detector.

[0090] Figure 9 shows the precision multiple-rotation absolute angle detection value obtained by integrating the count value of the segmented counter and the angle detection value of the precision absolute angle detector.

[0091] Figure 10 is a graph for explaining an example of the number-of-rotations calculation based on the count value of the segmented counter. DETAILED DESCRIPTION

[0092] Figure 1 is a block diagram for explaining a configuration example of a multiple-rotation angle detection device according to an embodiment of the present application. The multiple-rotation angle detection device 100 is a device that detects a multiple-rotation absolute angle of a rotation shaft 30 (one example of a rotating body) that rotates around a rotation axis 33, and generates a detection value thereof, i.e., a multiple-rotation absolute angle detection value. The multiple-rotation absolute angle refers to an absolute angle within an angle region covered by more than one rotation, i.e., multiple rotations. The multiple-rotation angle detection device 100 includes a precision absolute angle detector 1, a segmented counter 2, and a calculation device 4.

[0093] The precision absolute angle detector 1 is an angle sensor that generates a precision absolute angle detection value within one rotation period of the rotation shaft 30, i.e., 0 degrees to 360 degrees, at a higher resolution than the segmented 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 constituted to generate an absolute angle detection value of an angle region within one rotation period (0 degrees to 360 degrees) at a resolution of 16 bits (65536 levels).

[0094] Typically, the precision absolute angle detector 1 operates with power supplied from an external power source. Specifically, the multiple-rotation angle detection device 100 is provided with a power supply circuit 3 that can be connected to an external power source. When the power supply circuit 3 is connected to the external power source, the precision absolute angle detector 1 is supplied with power, and operates with the power. The precision absolute angle detector 1 inputs the 16-bit absolute angle detection value to the calculation device 4, for example, through serial communication.

[0095] The segment counter 2 counts segments into which one rotation cycle of the rotation axis 30 is divided (equally divided) based on the rotation of the rotation axis 30, and generates a count value indicating an angle value in units of segments in an angle region covered by a plurality of rotations (more than one rotation) of the rotation axis 30.

[0096] The segment counter 2 includes one (only one) power generation sensor 20, a magnetic field generation source 50 that rotates together with the rotation axis 30 around the rotation axis line 33, a sensor element MS that is different from (not a power generation sensor) the power generation sensor 20, a counter circuit 8, and a nonvolatile memory 9 that stores a count value. The nonvolatile memory 9 can be constituted by a FeRAM (ferroelectric random access memory). In the present embodiment, the timer circuit 8 and the nonvolatile memory 9 are assembled into one count 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.

[0097] The power generation sensor 20 generates a pulse voltage based on a change in a magnetic field accompanying the rotation of the magnetic field generation source 50. In the present embodiment, the sensor element MS is a magnetic sensor that detects a magnetic field of the magnetic field generation source 50 based on the rotation of the magnetic field generation source 50. One 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 supplies 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 acquired from the signal evaluation circuit 5 into digital data (serial signal), and supplies the signal as the 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 supplies the signal as the magnetic detection data to the counter circuit 8.

[0098] The rectification / power supply circuit 6 rectifies the pulse voltage generated by the power generation sensor 20, converts the pulse voltage into an appropriate voltage, and supplies the voltage to the sensor element MS, the signal evaluation circuit 5, the signal processing circuit 7, and the count memory IC 10 (the counter circuit 8 and the nonvolatile memory 9). Therefore, the sensor element MS, the signal evaluation circuit 5, the signal processing circuit 7, and the count memory IC 10 (the counter circuit 8 and the nonvolatile memory 9) can operate without accepting power supply from an external power source. That is, the segment counter 2 can operate by power generated by itself even when there is no supply of an external power source. The count memory IC 10 can accept power supply from the power supply circuit 3 and operate when the power supply circuit 3 is connected to an external power source.

[0099] The counter circuit 8 built in the count memory IC 10 performs a counting operation based on the polarity discrimination data (pulse polarity PP) and the magnetic detection data (MS) supplied from the signal processing circuit 7 in accordance with a prescribed counting logic. This counting operation is performed regardless of whether or not external power supply from the power supply circuit 3 is supplied. The count value obtained by this counting operation is stored in the nonvolatile memory 9. This count value is retained (nonvolatile storage) even when power supply is not supplied. When external power supply is supplied, the count memory 10 can supply the count value stored in the nonvolatile memory 9 to the arithmetic device 4 through serial communication.

[0100] The arithmetic device 4 receives power supply from the power supply circuit 3 and operates when the power supply circuit 3 is connected to external power supply. The arithmetic device 4 requests the precision absolute angle detector 1 for a precision absolute angle detection value and requests the nonvolatile memory 9 for a count value when external power supply is turned on. The precision absolute angle detector 1 supplies the precision absolute angle detection value to the arithmetic device 4 through serial communication. The nonvolatile memory 9 supplies the count value to the arithmetic device 4 through serial communication. The arithmetic device 4 integrates the precision absolute angle detection value and the count value, generates a multiple-rotation absolute angle detection value, and outputs it. The multiple-rotation absolute angle detection value outputted from the arithmetic device 4 is supplied, for example, to a higher-level controller (not shown) and used for rotation control of a motor or the like.

[0101] The arithmetic device 4 directly uses the count value supplied from the nonvolatile memory 9 and integrates it with the precision absolute angle detection value. That is, the count value used at the time of integration is the value directly counted in the segment timer 2 in the state where power supply is turned off, and the arithmetic device 4 does not perform correction processing related to error of the count value, specifically, does not perform synchronization processing for correcting error of the count value and synchronizing with the precision absolute angle detection value.

[0102] Figure 2A is a perspective view for explaining a configuration example of the segment counter 2, Figure 2B is a plan view thereof. Furthermore, Figure 2C is a front view as viewed in the direction of arrow IIC of Figure 2B The segment counter 2 includes a power generation sensor 20, a magnetic field generation source 50, and a sensor element MS (for example, a magnetic sensor).

[0103] The power generation sensor 20 is disposed on the first support body 31 and supported by the first support body 31. In the present embodiment, the first support body 31 also mounts the sensor element MS.

[0104] The magnetic field generating source 50 is fixed to the second support body 32. The second support body 32 is relatively moved with respect to the first support body 31. Specifically, the second support body 32 is coupled (fixed) to the rotating shaft 30, and rotates together with the rotating shaft 30 around the rotating axis 33. Therefore, the second support body 32 can be a part of a rotating body. In contrast to this, the first support body 31 is fixedly arranged, and kept in a non-rotating state. Thus, the magnetic field generating source 50 rotates around the rotating axis 33 together with the second support body 32, and relatively moves with respect to the first support body 31.

[0105] Typically, the rotating shaft 30 is rotated by a driving force from a driving shaft of an electric motor (not shown). In a case where the electric motor is bidirectionally driven, the rotating shaft 30 is correspondingly rotated in both directions of the counterclockwise direction CCW and the clockwise direction CW. The first support body 31 can be a printed wiring board arranged along a plane orthogonal to the rotating axis 33.

[0106] The magnetic field generating source 50 is composed of a 4-pole magnetization magnet M in a ring shape around the rotating axis 33. The magnetization direction is parallel to the rotating axis 33. When viewed from one direction of the rotating axis 33, the 4-pole magnetization magnet M has k (k is an integer of 2 or more) pairs of N-pole and S-pole arranged alternately on a circumference with the rotating axis 33 as the center (in the illustrated example, k = 2). The illustrated example shows a structure in which the pairs of N-pole and S-pole are arranged, and has k N-poles nl, n2,..., nk and k S-poles sl, s2,..., sk. Each of the magnetic poles nl, n2,..., nk; sl, s2,..., sk covers an angular region of 360 degrees / 2k (90 degrees in this embodiment) around the rotating axis 33. Therefore, the second support body 32 rotates together with the rotating shaft 30, and the magnetic field generating source 50 correspondingly rotates around the rotating axis 33, whereby an alternating magnetic field of k periods (2 periods in the illustrated example) is applied to the power generation sensor 20.

[0107] The power generation sensor 20 is mounted to one main surface of the first support body 31 (printed wiring board). The power generation sensor 20 includes a magnetic wire FE, a first magnetic flux conductor FL1 and a second magnetic flux conductor FL2 which are respectively magnetically coupled to both end portions of the magnetic wire FE. Between the first magnetic flux conductor FL1 and the second magnetic flux conductor FL2, a coil SP (induction coil) is wound around the magnetic wire FE. The first magnetic flux conductor FL1 and the second magnetic flux conductor FL2 are composed of soft magnetic members which are substantially the same shape and the same size. In more detail, the first magnetic flux conductor FL1 and the second magnetic flux conductor FL2 are symmetrically composed with respect to a symmetry plane 27 (virtual plane for explaining the geometric arrangement) orthogonal to the axial direction x at an axial center position 25 (hereinafter referred to as "axial center position 25") of the magnetic wire FE.

[0108] The magnetic wire FE is configured to exhibit a 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 magnetic layer) layer that undergoes a reversal of a magnetization direction even under a weak magnetic field, and the other of the core portion and the skin portion is a hard magnetic (hard magnetic layer) layer that does not undergo a reversal of a magnetization direction unless a strong magnetic field is applied.

[0109] Each of the magnetic flux conductors FL1, FL2 has a magnetic flux conducting end 21, 22 opposite to the detection region SR. The magnetic wire FE of the power generation sensor 20 is located on a tangent line of a circumference centered on the rotation axis 33, and an axial center position 25 of the magnetic wire FE is located on a point of tangency of the tangent line. The power generation sensor 20 is configured so that a magnetic force conducted from the two magnetic flux conductors FL1, FL2 reaches a balance when a center of one of the magnetic poles n1, n2,..., nk; s1, s2,..., sk encompassing an angle region of 360 degrees / 2k (90 degrees in this embodiment) around the rotation axis 33 matches the axial center position 25 of the magnetic wire FE. The coil SP generates a negative voltage pulse in a first state in which magnetic flux from the N pole n1, n2,..., nk is conducted from the first magnetic flux conductor FL1, and generates a positive voltage pulse in a second state in which magnetic flux from the N pole n1, n2,..., nk is conducted from the second magnetic flux conductor FL2.

[0110] In this embodiment, the first magnetic flux conductor FL1 and the second magnetic flux conductor FL2 include an axial orthogonal portion 41 extending in parallel with each other in a direction orthogonal to the axial direction x from both end portions of the magnetic wire FE, and an axial parallel portion 42 extending in a direction approaching to each other along the axial direction x from leading end portions of the axial orthogonal portion 41.

[0111] Both end portions of the magnetic wire FE are fixed to base end portions of the axial orthogonal portions 41 of the first magnetic flux conductor FL1 and the second magnetic flux conductor FL2, respectively. More specifically, a wire arrangement portion 23 is provided at the base end portion of the axial 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 penetrate the axial orthogonal portions 41 of the first magnetic flux conductor FL1 and the second magnetic flux conductor FL2 in the wire arrangement portion 23, and are fixed to the axial orthogonal portions 41. For example, the magnetic wire FE and the first magnetic flux conductor FL1 and the second magnetic flux conductor FL2 are coupled and fixed to each other by a resin (not shown) arranged in the hole or the groove constituting the wire arrangement portion 23. Thus, both end portions of the magnetic wire FE are magnetically coupled to the first magnetic flux conductor FL1 and the second magnetic flux conductor FL2, respectively.

[0112] The power generation sensor 20 is configured so that a side opposite to the magnetic wire FE with respect to the axial parallel portion 42 is set as the detection region SR for detecting a magnetic field.

[0113] Each magnetic flux conductor FL1, FL2 composed of a soft magnetic member has an axially orthogonal portion 41 of a substantially rectangular parallelepiped shape, and an axially parallel portion 42 of a substantially rectangular parallelepiped shape connected to an end portion, i.e., a front end portion, on the detection region SR side of the axially orthogonal portion 41, and has an L-letter shape bent at a right angle at a coupling portion of 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 FE, i.e., to shield between the magnetic wire FE and the detection region SR. The first magnetic flux conductor FL1 and the second magnetic flux conductor FL2 having mutually symmetrical shapes extend toward the axially central side of the magnetic wire FE, and their proximal ends 42a face each other at a spacing apart near the axially central position 25 of the magnetic wire FE. The proximal ends 42a are planes orthogonal to the axial direction x, and the two planes respectively forming the two proximal ends 42a are parallel to each other and opposite in the axial direction x.

[0114] The axially parallel portions 42 of the first magnetic flux conductor FL1 and the second magnetic flux conductor FL2 form magnetic flux conducting ends 21, 22 that form detection region opposing surfaces opposite the detection region SR. The magnetic flux conducting ends 21, 22 (detection region opposing surfaces) are flat surfaces parallel to the axial direction x. When a magnetic pole is disposed in the detection region SR, the magnetic flux conducting ends 21, 22 (detection region opposing surfaces) guide the magnetic flux from the magnetic pole to the inside of the first magnetic flux conductor FL1 and the second magnetic flux conductor FL2.

[0115] The axially parallel portions 42 of the first magnetic flux conductor FL1 and the second magnetic flux conductor FL2 are joined to a wiring pattern (not shown) formed on one main surface of the first support body 31 (printed wiring board), whereby the power generation sensor 20 is surface-mounted on the first support body 31 (printed wiring board). The power generation sensor 20 is disposed so that the axial direction x of the magnetic wire FE is along a tangent at a point (a point of tangency) on a circumference with the rotational axis 33 as a center axis, and so that the axially central position 25 of the magnetic wire FE coincides with the point of tangency. The detection region SR of the power generation sensor 20 is located on the side opposite the magnetic wire FE with respect to the axially parallel portions 42, and in the present example, is a region on the other main surface side of the first support body 31 (printed wiring board).

[0116] In this example, the second support body 32 is configured as a circular ring that surrounds the rotation axis 33. More specifically, the second support body 32 is configured by a circular ring-shaped plate-shaped body, is arranged along a plane orthogonal to the rotation axis 33, and is parallel to the first support body 31 (printed wiring board). In the second support body 32, the magnet M is fixed to a face of the first support body 31 (printed wiring board) opposite to the other main face described above. In this embodiment, the magnetic poles n1, s1, n2, s2,..., nk, sk of the magnet M are arranged at equal intervals in the circumferential direction around the rotation axis 33. In the specific example illustrated, four magnetic poles n1, s1, n2, s2 are arranged at an angle of 90 degrees around the rotation axis 33, and the magnet M is fixed to the second support body 32 so that these magnetic poles are opposite the first support body 31 (printed wiring board). The distance from the rotation axis 33 to the center of the magnetic poles n1, s1, n2, s2,..., nk, sk can be equal to the distance from the rotation axis 33 to the axial center position 25 of the magnetic wire FE. That is, in a plan view along the rotation axis 33, it can have a positional relationship in which the magnetic wire FE and the magnetic poles n1, s1, n2, s2,..., nk, sk are located on circumferences of equal radii with the rotation axis 33 as a center axis, and thus can be opposite in a direction parallel to the rotation axis 33. The second support body 32 is preferably a magnetic yoke configured by a soft magnetic body.

[0117] By the second support body 32 rotating together with the rotation shaft 30 around the rotation axis 33, the magnetic poles n1, s1, n2, s2,..., nk, sk move on the circumferential orbit 55 passing through the detection region SR with the rotation axis 33 as a center. The axial direction x of the magnetic wire FE is parallel to a tangent line passing through a certain point (tangent point) on the circumferential orbit 55, 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 line 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 circumference having the rotation axis 33 as a center and a radius equal to the circumferential orbit 55, and the magnetic wire FE is along a tangent line at the tangent point.

[0118] The distance of the first support body 31 and the second support body 32 in the direction along the rotation axis 33 is determined as an appropriate value at which the magnetic poles n1, s1, n2, s2,..., nk, sk can enter the detection region SR of the power generation sensor 20 by the rotation of the second support body 32.

[0119] In the printed wiring board constituting the first support 31, a sensor element MS constituted by, for example, a magnetic sensor is also mounted on the main face on which the power generation sensor 20 is mounted. The sensor element MS is configured to be able to detect the polarity of the magnetic pole opposite the central portion of the power generation sensor 20. The sensor element MS is constituted by, for example, a magnetic sensor such as a Hall IC, and outputs an H signal when an N pole is detected (when the N pole is opposite the central portion of the power generation sensor 20) and an L signal when an S pole is detected (when the S pole is opposite 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, outputs a discrimination signal that identifies the polarity of the magnetic pole opposite the central portion of the power generation sensor 20. In the present embodiment, the sensor element MS is configured to detect the magnetic pole at a position that is 180 degrees in phase around the rotation axis 33, that is, a position that is symmetrical about the rotation axis 33, with respect to the power generation sensor 20. When k is even (for example, 2), the sensor element MS detects a magnetic pole of the same polarity as the magnetic pole facing the central portion of the power generation sensor 20. When k is odd (for example, 3), the sensor element MS detects a magnetic pole of the opposite polarity to the magnetic pole facing the central portion of the power generation sensor 20. In either case, the sensor element MS is able to detect the polarity of the magnetic pole opposite the central portion of the power generation sensor 20.

[0120] With this structure, each time one magnetic pole pair nl, sl; n2, s2;...; nk, sk passes through the detection region SR along the circumferential orbit 55 by rotation in the counterclockwise direction CCW around the rotation axis 33, one negative pulse and one positive pulse are generated in that order. Further, each time one magnetic pole pair nl, sl; n2, s2;...; nk, sk passes through the detection region SR along the circumferential orbit 55 by rotation in the clockwise direction CW around the rotation axis 33, one positive pulse and one negative pulse are generated in that order. Then, the rotation position and the rotation direction can be identified by these pulses, and the sensor element MS that outputs the discrimination signal indicating the polarity of the magnetic pole located on the circumferential orbit 55 between the first magnetic flux conductor FLl and the second magnetic flux conductor FL2.

[0121] Figures 3A-3F An operation example is shown. Consider the case in which the rotation shaft 30 rotates in the counterclockwise direction CCW (counterclockwise direction) around the rotation axis 33. Figure 3A is an operation explanatory view in a state observed along the arrow IIC. Figure 2B is an operation explanatory view in a state observed along the arrow IIC. Figures 3B-3F is also an operation explanatory view in the same viewpoint. However, in Figures 3A-3F , the magnetic poles are developed into straight lines for explanation.

[0122] When reaching Figure 3A ( Figure 2BIn the state of ), the hard magnetic layer and soft magnetic layer of the magnetic conductor FE are magnetized in the direction from the second magnetic flux conductor FL2 towards the first magnetic flux conductor FL1, i.e., the set state (SET_N) for generating negative pulses. At this time, the area of ​​the first magnetic flux conductor FL1 opposite to the N and S poles is balanced with the area of ​​the second magnetic flux conductor FL2 opposite to the N and S poles. In other words, the magnetic field generating source 50, the power generation sensor 20, and their relative configuration are designed to achieve this state.

[0123] When the magnetic field source 50 and the rotating shaft 30 rotate slightly in the counterclockwise direction CCW from this state, as Figure 3B As shown, the proportion of the area of ​​the first magnetic flux conductor FL1 facing the N pole increases, while the proportion of the area of ​​the second magnetic flux conductor FL2 facing the N pole decreases. Consequently, a magnetic field is applied to the magnetic conductor FE from the first magnetic flux conductor FL1 toward the second magnetic flux conductor FL2. When the strength of this magnetic field reaches the operating magnetic field, the magnetization direction of the soft magnetic layer reverses, generating a negative voltage pulse. At this time, the sensor element MS detects the S pole (which is opposite to the center of the power generation sensor 20), thus generating an L signal.

[0124] Furthermore, when the rotating shaft 30 rotates counterclockwise in the CCW direction, the magnetic field from the first magnetic flux conductor FL1 towards the second magnetic flux conductor FL2 further strengthens and reaches a stable magnetic field, such as... Figure 3C As shown, the magnetization direction of the hard magnetic layer of the magnetic conductor FE is also reversed, becoming a set state (SET_P) for generating positive pulses.

[0125] As the rotating shaft 30 rotates further, and from Figure 3C The state reaches the point where the CCW rotates 90 degrees counterclockwise. Figure 3D In this state, the polarity is reversed, but the operation is the same as described above. That is, the hard magnetic layer and soft magnetic layer of the magnetic conductor FE are in a state where they are magnetized in the direction from the first magnetic flux conductor FL1 to the second magnetic flux conductor FL2, i.e., the set state (SET_P) for generating positive pulses. At this time, the areas of the first magnetic flux conductor FL1 opposite to the N and S poles, and the areas of the second magnetic flux conductor FL2 opposite to the N and S poles, are balanced.

[0126] When the magnetic field source 50 and the rotating shaft 30 rotate slightly in the counterclockwise direction CCW from this state, as Figure 3EAs shown, the proportion of the area of the 1st flux conducting member FL1 opposing the N pole decreases, and the proportion of the 2nd flux conducting member FL2 opposing the N pole increases. As a result, a magnetic field from the 2nd flux conducting member FL2 toward the 1st flux conducting member FL1 is applied to the magnetic wire FE. When the strength of this magnetic field reaches the operating magnetic field, the magnetization direction of the soft magnetic layer is reversed, and a positive voltage pulse is generated. At this time, the sensor element MS detects that the N pole opposes the central portion of the power generation sensor 20, and thus an H signal is generated.

[0127] Further, when the rotation axis 30 rotates in the counterclockwise direction CCW, the magnetic field from the 2nd flux conducting member FL2 toward the 1st flux conducting member FL1 further strengthens and reaches the stable magnetic field, as shown in (b) of FIG. 6. Figure 3F As shown, the magnetization direction of the hard magnetic layer of the magnetic wire FE is also reversed, and becomes a set state (SET_N) for generating a negative pulse. When the rotation axis 30 further rotates in the counterclockwise direction CCW from this state, a state equivalent to Figure 3A that shown in (a) of FIG. 6 is reached.

[0128] As a result, one pole pair passes through the detection region of the power generation sensor 20, and thus 2 pulses are generated. The magnetic field generation source 50 has k (2 in this example) pole pairs, and thus 2k (4 in this example) pulses are generated each time the rotation axis 30 rotates.

[0129] Figure 4 is a diagram for explaining the operation of the segment counter 2. In the present embodiment, the segment counter 2 counts segments obtained by dividing an angular region around the rotation axis 33 into Um (Um is an integer of 4 or more) segments, and generates a count value indicating the count result. The division of the segments corresponds to the arrangement of the magnets n1, s1, n2, s2,..., nk, sk. Typically, the plurality of magnets n1, s1, n2, s2,..., nk, sk are formed (magnetized) in regions around the rotation axis 33 divided at equal angles, and correspondingly, the segments are regions obtained by dividing an angular region around the rotation axis 33 into equal parts. Figure 4 In the present embodiment, an example in which Um = 4 is shown. Four segments are defined by four boundaries a, b, c, d set at 90-degree intervals around the rotation axis 33. The boundaries a, b, c, d are boundaries at which the count value of the segment counter 2 switches in response to the voltage pulse generated by the power generation sensor 20. Specifically, the boundaries a, b, c, d correspond to the angular positions at which any one of the poles opposes the central portion of the power generation sensor 20. As one example, a case in which the count is incremented when each pole moves in the counterclockwise direction CCW across the position opposing the central portion of the power generation sensor 20, and is decremented when moving in the clockwise direction CW, will be explained here.

[0130] When the magnetic poles n1, s1, n2, s2 are arranged at equal intervals on the circumference, the intervals between the boundaries a, b, c, d are 90 degrees of rotation angle. If the boundary a is the reference angle of 0 degrees, the boundary b is the angle of 90 degrees, the boundary c is the angle of 180 degrees, and the boundary d is the angle of 270 degrees.

[0131] In the present embodiment, the segment counter 2 is designed to count up when the rotation angle moves in the counterclockwise direction CCW across the boundaries a, b, c, d, and to count down when the rotation angle moves in the clockwise direction CW across the boundaries a, b, c, d. Accordingly, in the following description, the angle value around the rotation axis 33 is taken with the boundary a as the reference, and is increased toward the counterclockwise direction CCW.

[0132] The magnetic field generation source 50 is configured to generate an alternating magnetic field of k periods (k = 2 in the illustrated example) during one rotation of the rotation shaft 30 around the rotation axis 33. More specifically, in the present embodiment, the 2k magnetic poles n1, s1, n2, s2,..., nk, sk are arranged at equal angle intervals around the rotation axis 33.

[0133] The meanings of the symbols in the figure are as follows. "H" is a state value indicating that the sensor element MS detects the state of any one of the N poles n1, n2,..., nk, i.e., the state in which any one of the N poles n1, n2,..., nk opposes the central portion of the power generation sensor 20. "L" is a state value indicating that the sensor element MS detects the state of any one of the S poles s1, s2,..., sk, i.e., the state in which any one of the S poles s1, s2,..., sk opposes the central portion 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 that the power generation sensor 20 generates a positive pulse. "N" is a pulse polarity value indicating that the power generation sensor 20 generates a negative pulse. 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.

[0134] The state values supplied from the signal processing circuit 7 to the counter circuit 8 are expressed by combinations of these values, are updated each time the power generation sensor 20 generates a pulse, and are stored in the nonvolatile memory 9. "HP" is a state value indicating the state in which any one of the N poles n1, n2,..., nk generates a positive pulse in the state of opposing the central portion of the power generation sensor 20. "LN" is a state value indicating the state in which any one of the S poles s1, s2,..., sk generates a negative pulse in the state of opposing the central portion of the power generation sensor 20. "HN" is a state value indicating the state in which any one of the N poles generates a negative pulse in the state of opposing the central portion of the power generation sensor 20. "LP" is a state value indicating the state in which any one of the S poles generates a positive pulse in the state of opposing the central portion of the power generation sensor 20.

[0135] “SET_P” indicates the angle range for the ready state (set state) used to generate a positive pulse. “SET_N” indicates the angle range for the ready state (set state) used to generate a negative pulse.

[0136] The basic operation of segment counter 2 is as follows.

[0137] When the rotation axis 30 rotates counterclockwise in the CCW direction, near the boundaries a, b, c, and d, which correspond to rotation angles of 0 degrees, 90 degrees, 180 degrees, and 270 degrees respectively, through Figures 3A-3F The generator sensor 20, as shown, generates either a positive pulse or a negative pulse. It cycles through the following states: SET_P → HP (generating a positive pulse) → SET_N → LN (generating a negative pulse) → SET_P → ... The segment counter 2 increments by 1 for each of the HP and LN states. That is, it increments by 1 as the rotation angle increases through 0 degrees (boundary a), 90 degrees (boundary b), 180 degrees (boundary c), and 270 degrees (boundary d).

[0138] When the rotating shaft 30 rotates clockwise in the direction CW, near the boundaries a, b, c, and d, which correspond to rotation angles of 0, 90, 180, and 270 degrees respectively, the direction of magnetic pole movement is relative to... Figures 3A-3F The reverse-biased generator sensor 20 operates, generating a positive pulse and a negative pulse. It then cycles through the following states: SET_N → HN (generating a negative pulse) → SET_P → LP (generating a positive pulse) → SET_N → ... The segment counter 2 counts down by 1 at each of the HN and LP states. Specifically, it counts down by 1 as the rotation angle decreases through 0 degrees (boundary a), 90 degrees (boundary b), 180 degrees (boundary c), and 270 degrees (boundary d).

[0139] Figure 5 This table illustrates a more detailed example of the counting operation of the segment counter 2. The counter circuit 8, built into the counting memory IC 10, performs the counting operation by following the logic in this table. When the generator 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 is determined based on the combination of the updated state value (new: current value) and the previous state value (old: previous value). The counter circuit 8 reads the previous state value (old) from the non-volatile memory 9 and uses it to perform the counting operation.

[0140] When the updated state value is HP, if the previous state value is either of LN and HN (i.e., the polarity of the pulse is different), the upward counting action of +1 is performed. When the updated state value is HN, if the previous state value is either of LP and HP (i.e., the polarity of the pulse is different), the downward counting action of -1 is performed.

[0141] When the updated state value is LP, if the previous state value is either of HN and LN (i.e., the polarity of the pulse is different), the downward counting action of -1 is performed. When the updated state value is LN, if the previous state value is either of HP and LP (i.e., the polarity of the pulse is different), the upward counting action of +1 is performed.

[0142] The above is the basic counting action, and in addition, exceptional counting actions for compensating for the effects of the pulse omission described later are performed. Specifically, when the updated state value is equal to the previous state value, the count value is maintained (the change in the count value is "0"). In addition, when the updated state value is HP, if the previous state value is LP (i.e., the polarities of the pulse voltages are the same, and the polarity of the magnetic pole detected by the sensor element MS is different), a counting action of +2 is performed. When the updated state value is HN, if the previous state value is LN (i.e., the polarities of the pulse voltages are the same, and the polarity of the magnetic pole detected by the sensor element MS is different), a counting action of -2 is performed. When the updated state value is LP, if the previous state value is HP (i.e., the polarities of the pulse voltages are the same, and the polarity of the magnetic pole detected by the sensor element MS is different), a counting action of -2 is performed. When the updated state value is LN, if the previous state value is HN (i.e., the polarities of the pulse voltages are the same, and the polarity of the magnetic pole detected by the sensor element MS is different), a counting action of +2 is performed.

[0143] Thus, the counter circuit 8 identifies the rotation direction and the rotation position of the rotating shaft 30 based on the state value, i.e., using the output signal of the sensor element MS and the pulse voltage generated by the generator sensor 20, and updates the count value, and performs an action to write the count value to the nonvolatile memory 9.

[0144] The action of the counter circuit 8 is summarized as follows.

[0145] Step 1 (identification of the rotation direction) : The rotation direction is identified according to the combination of the polarity of the present pulse voltage and the state of the present sensor element (here, the polarity of the magnetic pole detected by the sensor element MS), and the sign of the count quantity is decided. For example, the state value H of the sensor element MS is expressed as "+1" and the state value L of the sensor element MS is expressed as "-1". Further, the pulse polarity value P is expressed as "+1" and the pulse polarity value N is expressed as "-1". Then, the product of the pulse polarity value and the sensor element state value is +1 or -1, which is the rotation direction value indicating the rotation direction. That is, the rotation direction value is "+1" when the state values are HP and LN, indicating the rotation direction of the counterclockwise direction CCW (refer to FIG. 6). Further, the rotation direction value is "-1" when the state values are HN and LP, indicating the rotation direction of the clockwise direction CW. The sign of these rotation direction values is the sign of the count quantity. In addition, the manner of assigning the sign is not limited to the above, as long as a different sign is assigned to the two sensor element state values and a different sign is assigned to the two pulse polarity values, and the sign of the product of the sensor element state value and the pulse polarity value indicates the rotation direction. Figure 4 ). Further, the rotation direction value is "-1" when the state values are HN and LP, indicating the rotation direction of the clockwise direction CW. The sign of these rotation direction values is the sign of the count quantity. In addition, the manner of assigning the sign is not limited to the above, as long as a different sign is assigned to the two sensor element state values and a different sign is assigned to the two pulse polarity values, and the sign of the product of the sensor element state value and the pulse polarity value indicates the rotation direction.

[0146] Step 2 (absolute value of the count quantity) : The absolute value of the count quantity is 1 when the polarity of the present pulse voltage is different from the polarity of the last pulse voltage. The absolute value of the count quantity is 0 when the polarity of the present pulse voltage is the same as the polarity of the last pulse voltage and the state of the present sensor element is the same as the state of the last sensor element. The absolute value of the count quantity is 2 when the polarity of the present pulse voltage is the same as the polarity of the last pulse voltage and the state of the present sensor element is different from the state of the last sensor element.

[0147] Step 3 (count quantity) : The count quantity is obtained by assigning the decided sign (Step 1) to the absolute value of the count quantity (Step 2).

[0148] Step 4 (count value update) : The count value is updated by adding the obtained count quantity (Step 3) to the last count value.

[0149] The order of Steps 1 and 2 can be interchanged, or Steps 1 and 2 can be executed simultaneously. Further, it can be configured to prepare the table shown in FIG. 7 in advance and use the table to obtain the count quantity. In this case, Steps 1, 2, and 3 are executed substantially simultaneously. Figure 5

[0150] Figure 6 is a diagram for explaining the influence of the pulse omission on the count value.

[0151] Consider the case where the rotation angle moves along the locus Tl. When the rotation angle moves in the counterclockwise direction CCW across the boundary a to generate a positive pulse at the position 51, the state values are HP (refer to FIG. 6). The rotation direction value is "+1", indicating the rotation direction of the counterclockwise direction CCW. The absolute value of the count quantity is 1. The count quantity is "+1", and the sign of the count quantity is the same as the sign of the rotation direction value. Therefore, the count value is updated to "+1" (refer to FIG. 8). Figure 3E ​If the rotation angle reaches the position where the magnetic wire FE of the power generation sensor 20 provides a stable magnetic field (refer to...). Figure 3F If the rotation direction reverses, the magnetic wire FE will not enter the negative pulse generation preparation state (SET_N). The rotation angle crosses boundary a in the clockwise direction CW, reaching position 52 where the state value HN should be generated. At this time, the negative pulse that should have been generated at position 52 is not generated (pulse missing), so the state value is not updated. Then, by rotating further in the clockwise direction CW, the magnetic wire FE enters the positive pulse generation preparation state (SET_P). Then, before the rotation angle reaches boundary d, the rotation direction reverses in the counterclockwise direction CCW at position 53, crossing boundary a again, and a positive pulse is generated again at position 51. Thus, the state value changes from HP to HP, so the count value remains unchanged (see reference). Figure 5 The same applies when the rotation direction is reversed. During this operation, the count value may include an error of ±1.

[0152] Next, consider the case where the rotation angle moves along trajectory T2. That is, the rotation angle moves clockwise CW across boundary d, thereby generating a positive pulse at position 61 with a state value of LP. If the rotation angle reaches the position that provides a stable magnetic field to the magnetic wire FE of the power generation sensor 20 (refer to...) Figure 3F If the rotation direction reverses, the magnetic wire FE will not enter the negative pulse generation preparation state (SET_N). The rotation angle crosses the boundary d in the counterclockwise direction CCW, reaching position 62 where the state value should be LN. At this time, the negative pulse that should have been generated at position 62 is not generated (pulse missing), so the state value is not updated. Afterwards, by further rotating in the counterclockwise direction CCW, the magnetic wire FE enters the positive pulse generation preparation state (SET_P). Then, the rotation angle in this state crosses the boundary a and moves in the counterclockwise direction CCW, generating a positive pulse at position 63, with the state value HP. Therefore, if the state value changes according to LP→LN and then according to LN→HP, the count value should change to +1+1=+2. However, due to the missing pulse at position 62, the state value does not pass LN but changes according to LP→HP. Therefore, at this time, by setting the count value to +2 (refer to...) Figure 5 This is used to compensate for the effects of missing pulses. The same applies when the rotation direction is reversed. During this operation, the count value may include an error of ±1.

[0153] The correct count value for the angle range of one rotation (360 degrees) is "0" in the interval S0 (0 degrees to 90 degrees) between boundaries a and b, "1" in the interval S1 (90 degrees to 180 degrees) between boundaries b and c, "2" in the interval S2 (180 degrees to 270 degrees) between boundaries c and d, and "3" in the interval S3 (270 degrees to 360 degrees) between boundaries d and a. In this case, when considering the counting error as described above, the angle ranges A0, A1, A2, and A3 with count values ​​of "0", "1", "2", and "3" respectively are as follows. Figure 6 As shown. These angular ranges A0, A1, A2, A3 are wider than the angular ranges (90 degrees) of each interval S0, S1, S2, S3, but as... Figure 6 As shown, all values ​​are less than one rotation (360 degrees). Therefore, there are no overlapping areas within the range covering multiple rotations. Thus, the number of rotations per unit can be determined using the count value and the angle detection value.

[0154] Figure 7 This diagram shows the relationship between the count value of segment counter 2 and the angle detection value of precision absolute angle detector 1. The horizontal axis represents the rotation angle (degrees) of rotation axis 30, and the vertical axis represents the absolute angle values ​​of multiple rotations, with one rotation (360 degrees) represented by a 16-bit (65536 levels) resolution. The diagram assumes the number of segments Um = 2k = 4.

[0155] As the rotating shaft 30 rotates, the angle detection value of the precision absolute angle detector 1 changes in a sawtooth wave pattern between 0 and 65536, as shown by reference numeral 70.

[0156] On the other hand, ideally, the count value of the segment counter 2 changes in a stepped manner as the rotation axis 30 rotates, as shown by reference numeral 71. For example, ideally, with 0 degrees as the reference, within each 90-degree (=360 / 4) angular interval with a central value at intervals of 90 degrees (=360 / 4), the count value becomes...-3, -2, -1, 0, 1, 2, 3... The segment counter 2 counts 4 times with each rotation; therefore, the step height for each count is 65536 / 4.

[0157] In reality, the count value of the segment counter 2, which includes the aforementioned error, may also be the same 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 is turned on, the count value of the segment counter is corrected, and synchronized with the angle detection value of the precision absolute angle detector. In this embodiment, this correction and synchronization processing are not performed; instead, the count value of the segment counter 2, which includes the error, is directly used, and the count value of the segment counter 2 and the angle detection value of the precision absolute angle detector 1 are integrated.

[0158] As shown in detail in Figure 7 Fig. 6, when the angle detection value of the precision absolute angle detector 1 is a certain value, for example, "38229" which corresponds to 210 degrees within the angle range of one rotation (0 degrees to 360 degrees), the count value of the segment counter 2 is checked. In the angle range covering multiple rotations, the angle detection value of the precision absolute angle detector 1 is "38229" (210 degrees) which is the multiple rotation angle of 360 degrees interval based on 210 degrees. That is, it is... -870 degrees, -510 degrees, -150 degrees, 210 degrees, 570 degrees, 930 degrees,.... At these multiple rotation angles, if the counting error is considered, the count value of the segment counter 2 can take the values as shown in Table 1.

[0159] [Table 1]

[0160] Multiple rotation angles Count value …… …… -870 degrees -11, -10 or -9 -510 degrees -7, -6 or -5 -150 degrees -3, -2 or -1 210 degrees 1, 2 or 3 570 degrees 5, 6 or 7 930 degrees 9, 10 or 11 …… ……

[0161] Figure 8 Fig. 6 shows the change of the count value of the segment counter 2 in the positive rotation angle range. Here, the value obtained by dividing the count value of the segment counter 2 by the number of segments (here, 4) (the value converted into the number of rotations N) is shown. As Figure 7 Similarly, the line 70 shows the angle detection value of the precision absolute angle detector 1. The stepped line 71 corresponds to the line 71 in Figure 7 Fig. 6. The line 71-1 shows the change of the count value including the error of -1 (the error when divided by the number of segments "4" is -0.25), and the line 71+1 shows the change of the count value including the error of +1 (the error when divided by the number of segments "4" is +0.25). From this Figure 8 The conclusion shown in Table 1 can also be obtained.

[0162] Thus, even if the error is considered, the range of each count value of the segment counter 2 is smaller than 360 degrees, and therefore, the same count value does not repeat at different multiple rotation angles. Therefore, by the combination of the count value of the segment counter 2 and the angle detection value detected by the precision absolute angle detector 1, the multiple rotation absolute angle detection value can be uniquely determined. Therefore, as shown in Figure 9 Fig. 6, it is not necessary to correct the counting error of the segment counter 2 and perform the processing for synchronizing the count value with the angle detection value detected by the precision absolute angle detector 1, and the multiple rotation absolute angle detection value can be generated by integrating them.

[0163] The arithmetic device 4 uses the count value m of the segment counter 2 and the angle detection value θ of the precision absolute angle detector 1, for example, performs the following operation, and integrates them to operate the multiple rotation absolute angle detection value θmt. The above Figure 9The operation result is shown. In the following equation, N represents the number of rotations (rotation amount) from the reference point (rotation position origin) of the rotation shaft 30. Uθ represents the angle detection amount per one rotation (for example, Uθ = 65536 (16 bits)), and corresponds to the resolution of the precision absolute angle detector 1. Um (for example, Um = 2k = 4) is the number of divisions per one rotation, and corresponds to the count of the division counter 2 at each rotation.

[0164] [Math. 1]

[0165] θmt = N x U θ + θ

[0166] N = INT (m / U m - θ / U θ + 1 / 2)

[0167] As in the above equation, the number of rotations N is obtained by dividing the count value m by the number of divisions Um, converting it into the number of rotations, subtracting the rotation amount (θ / Uθ) corresponding to the angle detection value θ therefrom, and rounding off. In the example of the above equation, the rounding off operation is performed by adding 1 / 2 and processing it using the integer function INT (a function for rounding off by removing the decimal part).

[0168] By multiplying the number of rotations N thus obtained by the angle detection amount Uθ per one rotation, the multiple rotation angle detection value with respect to the count value m of the division counter 2 can be obtained. By adding the precision angle detection value θ within one rotation thereto, the multiple rotation absolute angle detection value θmt representing the precision multiple rotation absolute angle can be obtained.

[0169] In order to perform a part or all of the above operation in the operation device 4, a table prepared in advance can be used as necessary.

[0170] In the actual operation of the number of rotations N, in order to avoid the processing of the value after the decimal point, it is convenient to use the following equation equivalent to the above equation.

[0171] [Math. 2]

[0172]

[0173] That is, the conversion value mUθ / Um obtained by multiplying the count value m by the angle detection amount Uθ per one rotation and dividing it by the number of divisions Um is used. The conversion value mUθ / Um is a value obtained by converting the count value m into the precision angle detection value. The conversion value mUθ / Um changes in a stepwise manner according to the rotation angle, as in the lines 71, 71-1, 71+1 of Figure 8 If the precision angle detection value θ (line 70) is subtracted from the conversion value mUθ / Um (lines 71, 71-1, 71+1) shown in Figure 8 , the number of rotations N (line 72) is obtained.Figure 8 Given line 70), calculate mUθ / Um-θ, then add Uθ / 2, and you will get... Figure 10 As shown, a stepped line exhibiting sawtooth variations is obtained in each step. Lines 80, 80-1, and 80+1 correspond to... Figure 8 The lines 71, 71-1, and 71+1 in the equation are equivalent to mUθ / Um-θ+Uθ / 2. By dividing this by Uθ and rounding it using the INT function, as shown... Figure 10 As shown by line 85 in the figure, the number of rotations N in the above formula can be obtained.

[0174] As described above, in this embodiment, the indexing counter 2 has only one power generation sensor 20 and a sensor element MS, and has a structure that applies an alternating magnetic field for more than two cycles to the magnetic wire of the power generation sensor 20 during each rotation. The count value of this segmented counter 2, including errors, can be directly processed and appropriately integrated with the angle detection value generated by the precision absolute angle detector 1, thereby obtaining precise absolute angle detection values ​​for multiple rotations. Therefore, it is not necessary to use multiple power generation sensors 20, nor is it necessary to determine the magnetization direction of the magnetic wire FE of the power generation sensor 20, or to perform complex correction or synchronization processing based on this. Therefore, the structure is simplified, and thus a small, low-cost, and high-resolution precision absolute angle detection device for multiple rotations can be provided.

[0175] Embodiment 2 of the present invention will be described.

[0176] The magnetic field generating source can be configured to include k (k≥2) magnets, which are arranged on a circumference centered on the rotation axis with magnetic poles of the same polarity facing the power generation sensor. In this case, an alternating magnetic field of k cycles can be applied to the magnetic wire during each rotation. In this case, the magnetic wire of the power generation sensor is preferably configured parallel to the tangent of the aforementioned circumference. Furthermore, the power generation sensor preferably includes a first magnetic flux conductor and a second magnetic flux conductor magnetically coupled to the first and second ends of the magnetic wire, respectively. As the magnetic field generating source rotates, the magnetic poles sequentially approach the first and second magnetic flux conductors. The power generation sensor generates a negative voltage pulse in a first state where the magnetic flux from the magnetic poles of the magnetic field generating source is conducted through the first magnetic flux conductor, 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 conductor. By counting these pulse voltages using the aforementioned segment counter, 2k segments can be counted during each rotation. In this scenario, typically, no other magnetic poles are positioned on the circular track through which the same polarity of the k magnets passes. Therefore, as the rotating body rotates in one direction, the same polarity magnetic poles sequentially align with the power generation sensor.

[0177] For example, consider the following scenario: In the magnetic conductor's soft and hard magnetic layers are magnetized in a position (for generating negative pulses) from the second flux conductor towards the first flux conductor, the magnetic field source rotates with the rotating body, and the magnetic pole approaches the first flux conductor. Magnetic flux from this pole is conducted through the first flux conductor, reversing the magnetization direction of the soft magnetic layer and generating a negative pulse. As the pole approaches the first flux conductor further, the magnetization direction of the hard magnetic layer also reverses, and the magnetic conductor becomes positioned for generating positive pulses. When the magnetic field source rotates further and the pole approaches the second flux conductor, magnetic flux from this pole is conducted through the second flux conductor. This reverses the magnetization direction of the soft magnetic layer, generating a positive pulse. As the pole approaches the second flux conductor further, the magnetization direction of the hard magnetic layer also reverses, and the magnetic conductor becomes positioned for generating negative pulses. Thus, when one magnetic pole passes through the detection area of ​​the power generation sensor, two pulses are generated.

[0178] In this configuration, the sensor element preferably detects whether the magnetic pole of the magnetic field generating source is located opposite the central portion of the power generation sensor. The segment boundary is the angular position where the magnetic pole is opposite the central portion of the power generation sensor. By detecting whether the magnetic pole of the magnetic field generating source is opposite the central portion of the power generation sensor using the sensor element, the rotational position and direction can be identified based on the outputs of the sensor element and the power generation sensor, just as in the embodiment described above.

[0179] The above describes two embodiments of the present invention, but as illustrated below, the present invention may also be implemented in other ways.

[0180] The above embodiments illustrate an example of a power generation sensor 20 using L-shaped magnetic flux conduction elements FL1 and FL2, but the magnetic flux conduction elements can also have other forms. For example, an I-shaped magnetic flux conduction element extending linearly from the magnetic wire FE toward the detection area can be used. Alternatively, a cylindrical magnetic flux conduction element structure with coil-sized elements at both ends of the magnetic wire can also be employed.

[0181] The above embodiments mainly illustrate that the magnetic field generating source 50 has two magnetic pole pairs (refer to...). Figure 2A In the case of 1 or 2 magnets of the same pole (Embodiment 2), it can also be configured to have 3 or more magnetic pole pairs or 3 or more magnets of the same pole, and to have a segment counter with 6 or more segments.

[0182] Moreover, the precision absolute angle detector 1 does not necessarily mean a single detector, as long as it has a function of obtaining an absolute angle within one rotation. For example, the precision absolute angle detector 1 can be configured by a plurality of detectors having a detection range below one rotation. As an example, an angle of one cycle / rotation can be obtained by arithmetic operation from a detection signal of a detector of 32 cycles / rotation and a detection signal of a detector of 31 cycles / rotation. Moreover, the arithmetic operation at this time is also performed by the arithmetic operation device 4.

[0183] While the embodiments of the present application have been described in detail, these are only specific examples for clarifying the technical contents of the present application, and the present application should not be interpreted as being limited to these specific examples, and the scope of the present application is only limited by the appended claims.

[0184] Explanation of Reference Numerals

[0185] 1 Precision absolute angle detector

[0186] 2 Section counter

[0187] 3 Power supply circuit

[0188] 4 Arithmetic operation device

[0189] 5 Signal evaluation circuit

[0190] 6 Rectifier / power supply circuit

[0191] 7 Signal processing circuit

[0192] 8 Counter circuit

[0193] 9 Nonvolatile memory

[0194] 10 Count memory IC

[0195] 20 Power generation sensor

[0196] 33 Rotation axis

[0197] 50 Magnetic field generation source

[0198] 100 Multi-rotation angle detection device

[0199] FE Magnetic wire

[0200] FL1 First magnetic flux conducting member

[0201] FL2 Second magnetic flux conducting member

[0202] M Magnet

[0203] MS Sensor element

[0204] SP Coil

[0205] SR detection region

[0206] a, b, c, d boundaries

[0207] n1, n2 N-pole

[0208] s1, s2 S-pole.

Claims

1. A multi-turn angle detection device that generates a multi-turn absolute angle detection value of a rotary body that rotates around a rotary axis, characterized by, The application includes: a segment counter that counts segments into which a rotation cycle of the rotating body is divided and generates a count value in an angle region of more than one rotation of the rotating body based on rotation of the rotating body; a precision absolute angle detector that operates with power supplied from outside and generates an absolute angle detection value within one rotation cycle of the rotating body at a higher resolution than the segments; an arithmetic device that operates with power supplied from outside and integrates the count value of the segment counter and the absolute angle detection value of the precision absolute angle detector to generate a multi-rotation absolute angle detection value of the rotating body, the segment counter includes a power generation sensor, a magnetic field generation source that rotates together with the rotating body around the rotation axis, a sensor element that is different from the power generation sensor, and a nonvolatile memory that stores the count value, the power generation sensor has a magnetic conductor that exhibits a large Barkhausen effect and a coil wound around the magnetic conductor, and generates a pulse voltage by a magnetic field change accompanying rotation of the magnetic field generation source, the magnetic field generation source applies an alternating magnetic field of two or more periods to the axial direction of the magnetic conductor per rotation of the rotating body, the segment counter operates with the energy of the pulse voltage generated by the power generation sensor without receiving power supplied from outside, and if the power generation sensor generates a pulse voltage, the polarity of the pulse voltage, the state of the sensor element at the time of generation of the pulse voltage, the polarity of the previous pulse voltage, the state of the sensor element at the time of generation of the previous pulse voltage, and the count value updated and stored in the nonvolatile memory due to generation of the previous pulse voltage are used to identify the rotation direction and the rotation position of the rotating body, update the count value, and store it in the nonvolatile memory, in the segment counter, the rotation direction of the rotating body is identified based on the combination of the polarity of the present pulse voltage and the state of the present sensor element, and the sign of the count is determined, when the polarity of the present pulse voltage is different from the polarity of the previous pulse voltage, the absolute value of the count is set to 1, when the polarity of the present pulse voltage is the same as the polarity of the previous pulse voltage and the state of the present sensor element is the same as the state of the previous sensor element, the absolute value of the count is set to 0, when the polarity of the present pulse voltage is the same as the polarity of the previous pulse voltage and the state of the present sensor element is different from the state of the previous sensor element, the absolute value of the count is set to 2, the count obtained by assigning the determined sign to the absolute value of the count is added to the previous count value to update the count value, ​ The operation device integrates the count value of the segment counter and the absolute angle detection value of the precision absolute angle detector using the count value stored in the nonvolatile memory directly when receiving power supply from the outside, and generates a multi-revolution absolute angle detection value of the rotating body.

2. The multi-revolution angle detection device according to claim 1, wherein When the power generation sensor generates a pulse voltage, the segment counter stores the polarity of the pulse voltage and the output state of the sensor element at the time of generation of the pulse voltage in the nonvolatile memory.

3. The multi-revolution angle detection device according to claim 1, wherein The segment counter counts segments obtained by dividing one revolution of the rotating body into four or more.

4. The multi-revolution angle detection device according to any one of claims 1 to 3, wherein The magnetic field generation source includes two or more pairs of magnetic poles in which N poles and S poles are alternately arranged on a circumference centered on the rotation axis.

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

6. The multi-revolution angle detection device according to claim 5, wherein The power generation sensor has a first magnetic flux conductor and a second magnetic flux conductor which are respectively magnetically coupled to both end portions of the magnetic wire.

7. The multi-revolution angle detection device according to claim 4, wherein The sensor element detects the polarity of the magnetic pole opposite to the central portion of the power generation sensor.

8. A segment counter which counts segments obtained by dividing one revolution of a rotating body rotating around a rotation axis in an angle region exceeding one revolution of the rotating body, and generates a count value, characterized by including a power generation sensor, a magnetic field generation source rotating around the rotation axis together with the rotating body, a sensor element different from the power generation sensor, a nonvolatile memory storing the count value, and a counter circuit updating the count value, The power generation sensor has a magnetic wire exhibiting a large Barkhausen effect and a coil wound around the magnetic wire, and generates a pulse voltage by a change in magnetic field accompanying rotation of the magnetic field generation source, The magnetic field generation source applies two or more periods of alternating magnetic field to the axial direction of the magnetic wire at each revolution of the rotating body, If the power generation sensor generates a pulse voltage, the counter circuit identifies the rotation direction and the rotation position of the rotating body using the polarity of the pulse voltage, i.e., the polarity of the present pulse voltage, the output state of the sensor element at the time of generation of the pulse voltage, i.e., the present sensor element state, the polarity of the previous pulse voltage, the output state of the sensor element at the time of generation of the previous pulse voltage, i.e., the previous sensor element state, and the count value updated and stored in the nonvolatile memory due to the generation of the previous pulse voltage, i.e., the previous count value, updates the count value and stores it in the nonvolatile memory, In the counter circuit, the rotation direction of the rotating body is identified according to the combination of the polarity of the present pulse voltage and the present sensor element state, and the sign of the count is determined, when the polarity of the present pulse voltage is different from the polarity of the previous pulse voltage, the absolute value of the count is set to 1, when the polarity of the present pulse voltage is the same as the polarity of the previous pulse voltage and the present sensor element state is the same as the previous sensor element state, the absolute value of the count is set to 0, when the polarity of the present pulse voltage is the same as the polarity of the previous pulse voltage and the present sensor element state is different from the previous sensor element state, the absolute value of the count is set to 2, the count value obtained by assigning the determined sign to the absolute value of the count is added to the previous count value, thereby updating the count value.

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