JP2015059763A - Rotation angle sensor and rotation angle detection system including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation angle sensor having a narrow pulse interval (a pulse cycle) and outputting a signal having suppressed signal deformation, and a rotation angle detection system including the same.SOLUTION: A rotation angle sensor detects a rotation angle of a rotor (400) formed by alternately coupling first members (410) with a second member (420) in a rotation direction so as to periodically vary a rotation magnetic flux and has a plurality of magnetoelectric transducers (21 to 24) arranged at a regular interval in the rotation direction. An adjacent angle formed of two lines connecting each of two adjacent magnetoelectric transducers with the rotation center (RC) of the rotor is equal to a value θ/n obtained by dividing the adjacent angle θ by a natural number n, when n is a natural number of 2 or more, and an adjacent angle formed of two lines connecting each of two first members adjacent through the second member with the rotation center is θ.

Description

  The present invention relates to a rotation angle sensor that detects a rotation angle of a rotating body, and a rotation angle detection system including the rotation angle sensor.

  Conventionally, as disclosed in Patent Document 1, for example, an engine control device that controls an engine based on a crank signal of a pulse train at predetermined angular intervals corresponding to rotation of a crankshaft of the engine has been proposed.

JP 2005-133614 A

  In order to control the engine with high accuracy, the angular interval of the pulse train included in the crank signal is required to be narrow. The crankshaft is formed by alternately connecting the first member and the second member having different shapes or magnetic poles along the rotation direction so that the rotating magnetic flux periodically fluctuates, and the rotation of the first member and the second member is performed. The corresponding pulse is input to the engine control device as a crank signal. The pulse angular interval is directly proportional to the angular interval of the first member (second member). If the angular interval is reduced, the angular interval of the pulse is also reduced. In this way, the engine can be controlled with high accuracy by narrowing the angular interval of the pulses.

  However, as described above, since the pulse angle interval depends on the angle interval of the first member (second member), the pulse angle interval cannot be reduced regardless of the shape of the crankshaft. Of course, when the angular interval of the first member is narrowed, the angular interval of the pulses is dense. However, since the rise time and the fall time of the pulse are finite, if the angular interval of the pulses is narrow, the pulses are connected and the signal may be destroyed.

  SUMMARY OF THE INVENTION In view of the above problems, the present invention has an object to provide a rotation angle sensor that outputs a signal with a narrow pulse interval (pulse period) and suppressed signal collapse, and a rotation angle detection system including the rotation angle sensor. To do.

  In order to achieve the above object, the present invention provides a rotation angle sensor for detecting a rotation angle of a rotating body based on a rotating magnetic flux generated by the rotation of the rotating body (400), the rotating magnetic flux generated by the rotation of the rotating body. The first member (410) and the second member (420) have a plurality of magnetoelectric conversion elements (21 to 24) for converting the fluctuations of the first and second rotations into electrical signals, and the rotating body periodically changes the rotating magnetic flux. Are alternately connected along the rotation direction, and the plurality of magnetoelectric conversion elements are arranged at equal intervals along the rotation direction, and each of the two adjacent magnetoelectric conversion elements and the rotation center of the rotating body ( RC) is an adjacent angle formed by two lines connecting two first members adjacent to each other via one second member, and n being a natural number of 2 or more. When the angle is θ, the adjacent angle θ is a natural number n Independent signal lines (151 to 154) corresponding to each of the plurality of magnetoelectric conversion elements are connected to the processing unit (200) for processing the output signal of the magnetoelectric conversion elements. It is characterized by.

  In the following, in order to simplify the explanation, a pulse signal corresponding to the first member (410) and the second member (420) is output from each of the plurality of magnetoelectric transducers (21 to 24). To do. Specifically, when the first member (410) passes in front of the magnetoelectric conversion elements (21 to 24), the Hi signal is output, and when the second member (420) passes, the Lo signal is output from the magnetoelectric conversion elements (21 To 24).

  As described above, in the present invention, the adjacent angle between two adjacent magnetoelectric transducers is equal to the value θ / n obtained by dividing the adjacent angle θ between two adjacent first members (410) by the natural number n. According to this, when one first member (410) rotates by the adjacent angle θ, a pulse signal corresponding to one first member (410) is output from each of the plurality of magnetoelectric transducers (21 to 24). . In addition, since the adjacent angle of the plurality of magnetoelectric conversion elements (21 to 24) is θ / n as described above, a pulse signal different in phase by θ / n is output from each adjacent magnetoelectric conversion element. . Therefore, when these plural pulse signals are connected to the processing unit (200) via the signal lines (151 to 154), the pulses included in each pulse signal are sequentially input to the processing unit (200). Although the adjacent angle of (410) is θ, a pulse signal obtained when the adjacent angle of the first member (410) is θ / n is obtained. Thus, by increasing the number of the magnetoelectric conversion elements (21 to 24), even when the adjacent angle of the first member (410) is wide, a pulse signal with a narrow pulse adjacent interval (pulse period) is obtained. be able to. That is, a pulse signal having a narrow pulse period can be obtained regardless of the shape of the rotating body (400). Further, as described above, since a plurality of pulse signals whose phases are shifted by θ / n are sequentially input, it is possible to suppress the collapse of the pulses included in each pulse signal.

  Independent signal lines (151 to 154) corresponding to the plurality of magnetoelectric conversion elements (21 to 24) are connected to the processing unit (200). Thereby, a pulse signal corresponding to the adjacent angle θ is input to each signal line (151 to 154). Therefore, since the pulse density is coarser than the configuration in which the pulse signal having the adjacent angle θ / 2 is input to each signal line (151 to 154), the noise resistance of the pulse signal is enhanced.

It is a top view which shows roughly the position of a rotation angle sensor and a rotary body. It is a block diagram which shows a rotation angle detection system. It is a timing chart which shows the pulse signal and processing signal corresponding to normal rotation. It is a timing chart for demonstrating the pulse signal and processing signal corresponding to reverse rotation. It is a timing chart for demonstrating the pulse signal and processing signal corresponding to a missing tooth. It is a timing chart for demonstrating the pulse signal and processing signal corresponding to normal rotation, reverse rotation, and a missing tooth. It is a timing chart for demonstrating each pulse period of the pulse signal corresponding to normal rotation, and the pulse signal corresponding to reverse rotation. It is a top view for demonstrating the modification of a rotation angle sensor. It is a timing chart which shows the pulse signal output from the rotation angle sensor shown in FIG. 8, and a rotation angle signal. It is a block diagram which shows the modification of a rotation angle detection system. 11 is a timing chart for explaining a pulse signal and a processing signal corresponding to reverse rotation in the rotation angle detection system shown in FIG. 10. It is a timing chart for demonstrating the pulse signal and processing signal in the structure in which each of a pulse number and a pulse width is converted at the time of reverse rotation. It is a timing chart for demonstrating the pulse signal and processing signal in the structure by which a voltage level is converted at the time of reverse rotation. It is a timing chart for demonstrating the pulse signal and processing signal in the structure in which each of a voltage level and the number of pulses is converted at the time of reverse rotation. It is a timing chart for demonstrating the pulse signal and processing signal in the structure in which each of a voltage level, the number of pulses, and a pulse width is converted at the time of reverse rotation. It is a top view which shows the modification of a rotary body.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
A rotation angle sensor according to the present embodiment and a rotation angle detection system including the rotation angle sensor will be described with reference to FIGS. In the following, the plane at the same height position where each of the rotating body 400 and the magnetoelectric transducer 20 is arranged is a specified plane, orthogonal to the specified plane, and the rotation center RC of the rotating body 400 (x mark shown in FIG. 1). The penetration direction is indicated as the axial direction. A direction around the axial direction is indicated as a rotational direction (for example, a two-dot chain line shown in FIG. 1), and a direction orthogonal to the axial direction is indicated as a radial direction (for example, a one-dot chain line or a solid line shown in FIG. 1). The rotating body 400 has a property of rotating forward in one direction (counterclockwise) in the rotation direction and reverse in the opposite direction (clockwise). In FIG. 1, the forward rotation direction is indicated by a solid line arrow around the rotation center RC, and the reverse rotation direction is indicated by a broken line arrow around the rotation center RC.

  As shown in FIGS. 1 and 2, the rotation angle detection system 300 includes a rotation angle sensor 100, a signal line 150, and a processing unit 200, and the rotation angle sensor 100 and the processing unit 200 include a signal line 150. It is electrically connected via. The rotation angle sensor 100 generates an electrical signal corresponding to the rotation of the rotating body 400, and the processing unit 200 outputs an output signal of the rotation angle sensor 100 input from the rotation angle sensor 100 via the signal line 150. It is something to process. Although not shown, the signal processed by the processing unit 200 is input to a control unit that controls the rotation of the rotating body 400 located in the subsequent stage. The control unit controls the rotation state of the rotator 400 based on the input signal.

  As shown in FIG. 1, the rotation angle sensor 100 includes a magnetic field generation unit 10, a magnetoelectric conversion element 20, and a conversion unit 30. The magnetoelectric conversion element 20 is provided between the rotator 400 and the magnetic field generation unit 10, and a bias magnetic field generated from the magnetic field generation unit 10 is applied to the rotator 400 via the magnetoelectric conversion element 20. The rotating body 400 includes a first member 410 having a convex portion formed on a surface thereof and a second member 420 having a concave portion alternately connected along the rotational direction, and the convex portion is along the rotational direction. The recesses are formed at equal intervals along the rotation direction. As the rotating body 400 rotates, the members 410 and 420 (unevenness) rotate, and the bias magnetic field (rotating magnetic flux) transmitted through the magnetoelectric conversion element 20 varies due to the rotation. The magnetoelectric conversion element 20 converts the fluctuation of the bias magnetic field due to the rotation of the rotating body 400 into an electric signal. The electrical signal converted by the magnetoelectric conversion element 20 is output to the processing unit 200 via the conversion unit 30 and the signal line 150 as shown in FIG. The processing unit 200 detects the rotation state (rotation angle and number of rotations) of the rotating body 400 based on the input electrical signal.

  The rotation angle sensor 100 includes a plurality of the magnetoelectric conversion elements 20 described above, and the plurality of magnetoelectric conversion elements 20 are arranged at equal intervals along the rotation direction. As illustrated in FIG. 1, the rotation angle sensor 100 according to the present embodiment includes two magnetoelectric conversion elements 21 and 22 as the magnetoelectric conversion element 20. The two magnetoelectric conversion elements 21 and 22 are arranged along the rotation direction, and the adjacent interval is determined according to the adjacent angle of the first member 410 (hereinafter referred to as the convex portion 410) of the rotating body 400. Yes. Two lines (two solid lines along the radial direction shown in FIG. 1) connecting each of the two adjacent protrusions 410 and the rotation center CP via one second member 420 (hereinafter referred to as a recess 420) are formed. When the adjacent angle is θ and n is a natural number of 2 or more, two lines connecting the two adjacent magnetoelectric transducers 21 and 22 and the rotation center CP (a solid line and a one-dot chain line along the radial direction shown in FIG. 1) Is equal to a value θ / n obtained by dividing the adjacent angle θ by a natural number n. In the present embodiment, the natural number n is the same as the number of the magnetoelectric conversion elements 21 and 22 and is 2. Therefore, the adjacent angle between two adjacent magnetoelectric conversion elements 21 and 22 is θ / 2, and an electrical signal corresponding to the rotation of the rotating body 400 output from each of the magnetoelectric conversion elements 21 and 22 is θ / 2. Only out of phase. In addition, the electrical signal output from each of the magnetoelectric conversion elements 21 and 22 is a triangular wave. If a sine wave is output from the first magnetoelectric conversion element 21, the second magnetoelectric conversion element 22 is more than the sine wave. A sine wave whose phase is earlier or slower by θ / 2 is output.

  As described above, the rotating body 400 is formed with a plurality of convex portions 410 arranged at equal intervals along the rotation direction, but a part (for example, one) of the plurality of convex portions 410 is missing and rotated. A third member whose length in the direction is longer than that of the recess 420 (hereinafter referred to as chipped teeth) is formed. Therefore, although the electrical signal according to the above-mentioned unevenness | corrugation 410,420 and the electrical signal according to a missing tooth are each output from the magnetoelectric conversion element 20, in this embodiment, the rotation angle signal mentioned later is simplified. Therefore, the illustration of the electrical signal corresponding to the missing tooth is omitted. The electrical signal corresponding to the irregularities 410 and 420 is the above-described triangular wave, and this triangular wave is converted into a pulse signal by the converter 30.

  The conversion unit 30 includes pulse signal conversion units 31 and 32, voltage level conversion units 33 and 34, and a determination unit 35. The pulse signal conversion units 31 and 32 correspond to the magnetoelectric conversion elements 21 and 22, respectively, and convert the respective output signals into pulse signals. The voltage level converters 33 and 34 convert (adjust) each voltage level corresponding to each of the plurality of pulse signals output from the pulse signal converters 31 and 32. The determination unit 35 determines the reference position of the rotation direction and the rotation angle of the rotating body 400 based on the output signals of the magnetoelectric conversion elements 21 and 22, and the pulse signal conversion units 31 and 32 and the voltage level based on the determination. The converters 33 and 34 are controlled. The pulse signals output from the voltage level converters 33 and 34 are input independently to the corresponding signal lines 151 and 152, respectively.

  The first pulse signal conversion unit 31 has a threshold value, and the output signal of the first magnetoelectric conversion element 21 is converted into a pulse signal based on the magnitude relationship between the threshold value and the electric signal output from the first magnetoelectric conversion element 21. Convert to The first voltage level converter 33 adjusts the voltage level of the pulse signal output from the first pulse signal converter 31, and the adjusted pulse signal (hereinafter referred to as the first pulse signal) is the first signal line. 151 is output. The first pulse signal input to the first signal line 151 is used by the processing unit 200 to detect the rotation angle and rotation direction of the rotating body 400.

  Similarly, the second pulse signal conversion unit 32 has a threshold value, and the output of the second magnetoelectric conversion element 22 is based on the magnitude relationship between the threshold value and the electric signal output from the second magnetoelectric conversion element 22. Convert the signal to a pulse signal. The second voltage level converter 34 adjusts the voltage level of the pulse signal output from the second pulse signal converter 32, and the adjusted pulse signal (hereinafter referred to as a second pulse signal) is supplied to the second signal line. It outputs to 152. The second pulse signal input to the second signal line 152 is used by the processing unit 200 to detect the rotation angle of the rotating body 400 and its reference position.

  The determination unit 35 according to the present embodiment includes a first pulse signal conversion unit 31 and a second voltage level conversion unit based on the determination of the reference position of the rotation direction of the rotator 400 and the rotation angle of the rotator 400. 34 is controlled. More specifically, the determination unit 35 outputs an instruction signal to the first pulse signal conversion unit 31 to convert the pulse width of the first pulse signal when the reverse rotation of the rotation body 400 is determined, and the rotation of the rotation body 400 When the reference position of the angle is detected, an instruction signal is output to the second voltage level converter 34 so as to convert the voltage level of the second pulse signal.

  When the rotating body 400 is rotating forward, the first pulse signal conversion unit 31 converts the output signal of the first magnetoelectric conversion element 21 into a pulse signal having the first pulse width, and when the rotating body 400 is rotating reversely. , And converted into a pulse signal having a second pulse width different from the first pulse width. In other words, when the instruction signal is not input from the determination unit 35, the first pulse signal conversion unit 31 converts the output signal of the first magnetoelectric conversion element 21 into a pulse signal having the first pulse width, and determines the determination unit 35. When the instruction signal is input from, it is converted into a pulse signal having the second pulse width.

  On the other hand, since the second pulse signal conversion unit 32 is not electrically connected to the determination unit 35, no instruction signal is input from the determination unit 35. Therefore, the second pulse signal conversion unit 32 converts the output signal of the second magnetoelectric conversion element 22 into a pulse signal having a predetermined pulse width regardless of the rotation direction of the rotating body 400. The second pulse signal conversion unit 32 converts the output signal of the second magnetoelectric conversion element 22 into a pulse signal having the first pulse width in the same manner as the first pulse signal conversion unit 31.

  Since the first voltage level conversion unit 33 is not electrically connected to the determination unit 35, no instruction signal is input. Accordingly, the first voltage level conversion unit 33 converts the pulse signal output from the first pulse signal conversion unit 31 to a predetermined voltage level without depending on the unevenness 410, 420 or chipped teeth formed on the rotating body 400. . As shown in FIGS. 3 to 6, in the present embodiment, the first voltage level conversion unit 33 converts the pulse signal described above into a pulse signal composed of a first level voltage level and a second level voltage level.

  On the other hand, the second voltage level conversion unit 34 converts the pulse signal output from the second pulse signal conversion unit 32 to the first level and the first level when the irregularities 410 and 420 pass in front of the magnetoelectric conversion element 20. When the missing tooth passes in front of the magnetoelectric conversion element 20, the voltage level is converted into the pulse signal of the third level and the second level. In other words, when the instruction signal is not input from the determination unit 35, the second voltage level conversion unit 34 converts the pulse signal output from the second pulse signal conversion unit 32 into a pulse composed of the first level and the second level. When the instruction signal is input from the determination unit 35, the signal is converted into a pulse signal composed of the third level and the second level. Hereinafter, the first level is indicated as Lo level, the second level as Hi level, and the third level as Mid level. The Mid level is a voltage level between the Lo level and the Hi level.

  As described above, the positions of the magnetoelectric conversion elements 21 and 22 are shifted by θ / 2 in the rotation direction. Therefore, when one electrical signal of the magnetoelectric transducers 21 and 22 rises, the other electrical signal is in a state before that. On the contrary, when one electrical signal falls, the other electrical signal is in front of it. The behavior of this electric signal is reversed between forward rotation and reverse rotation. The determination unit 35 determines normal rotation and reverse rotation of the rotating body 400 based on the relationship between the behaviors of the two electric signals.

  Further, as described above, the rotating body 400 has chipped teeth. Therefore, an electrical signal corresponding to this missing tooth is output from each of the magnetoelectric transducers 21 and 22. Based on the electrical signal corresponding to the missing tooth, the determination unit 35 determines that the rotating body 400 has passed the reference position of the rotation angle, and outputs an instruction signal to the second voltage level conversion unit 34. Incidentally, in the timing charts shown in FIG. 3 to FIG. 6, illustration of electric signals of the magnetoelectric conversion elements 21 and 22 corresponding to the missing teeth is omitted.

  As the signal line 150, there are independent signal lines 151 and 152 corresponding to the magnetoelectric conversion elements 21 and 22, respectively, which connect the magnetoelectric conversion elements 21 and 22 to the processing unit 200 independently. As shown in FIG. 2, the first magnetoelectric conversion element 21 is connected to the first signal line 151 via the first conversion units 31 and 33, and the second magnetoelectric conversion element 22 is connected to the second conversion units 32 and 34. They are connected to the second signal line 152 via each. Each of the signal lines 151 and 152 is independently connected to the processing unit 200. Thereby, the electric signal (first pulse signal) of the first magnetoelectric conversion element 21 converted by the first conversion units 31 and 33 is independently input to the processing unit 200, and the second conversion units 32 and 34 The converted electric signal (second pulse signal) of the second magnetoelectric conversion element 22 is input to the processing unit 200 independently.

  The processing unit 200 processes the output signal of the magnetoelectric conversion element 20 via the conversion unit 30. The processing unit 200 superimposes the output signals (first pulse signal and second pulse signal) of the magnetoelectric conversion elements 21 and 22 converted by the conversion unit 30, thereby narrowing the adjacent interval (pulse period) of the pulses. A rotation angle signal is obtained, and the rotation angle and the number of rotations of the rotating body 400 are detected based on this signal. The processing unit 200 includes a counter, and detects the rotation angle and the number of rotations by counting the rising edge or falling edge of the pulse included in the rotation angle signal. As described above, the pulse width of the first pulse signal is converted by the first pulse signal conversion unit 31 according to the rotation direction of the rotating body 400. Further, the voltage level of the second pulse signal is converted by the second voltage level conversion unit 34 by the missing teeth of the rotating body 400. Therefore, the processing unit 200 detects the rotation direction of the rotator 400 based on the pulse width of the first pulse signal, and detects the reference position of the rotation angle of the rotator 400 based on the voltage level of the second pulse signal.

  As illustrated in FIGS. 3 to 6, the processing unit 200 generates a processing signal based on the first pulse signal and the second pulse signal. That is, the processing unit 200 generates the above-described rotation angle signal, the direction signal indicating the rotation direction of the rotating body 400, and the reference signal indicating the reference position of the rotation angle of the rotating body 400 as processing signals. The direction signal is a Lo level signal when the rotating body 400 is rotating forward, and is the same pulse signal as the rotation angle signal when rotating the rotation body 400 is rotating backward. The reference signal is a Lo level signal when the irregularities 410 and 420 pass in front of the magnetoelectric conversion element 20, and is a signal in which one pulse rises when a missing tooth passes. These processing signals are input to a control unit located in the subsequent stage.

  Hereinafter, the first pulse signal, the second pulse signal, the rotation angle signal, the direction signal, and the reference signal will be described with reference to FIGS. FIG. 3 shows a pulse signal and a processing signal when the rotator 400 is rotating forward, and FIG. 4 shows a pulse signal and a processing signal when the rotator 400 is turned from normal rotation to reverse rotation. FIG. 5 shows a pulse signal and a processed signal when the chipped tooth passes in front of the magnetoelectric conversion element 20, and FIG. 6 shows that the rotating body 400 changes from normal rotation to reverse rotation and the front of the magnetoelectric conversion element 20 is chipped. The pulse signal and processing signal when the tooth has passed are shown.

As described above, the adjacent angle formed by the two lines connecting the two adjacent convex portions 410 and the rotation center CP is represented by θ. Therefore, when the rotating body 400 is rotated by the adjacent angle θ, one unevenness 410, 420 passes in front of each of the magnetoelectric conversion elements 21, 22. When this one unevenness | corrugation 410,420 passes, each magnetoelectric conversion element 21 and 22 outputs the triangular wave for 1 period. Therefore, as shown in FIG. 3, the first pulse signal and the second pulse signal having one cycle (hereinafter referred to as T _θ ) as a cycle are output from the voltage level conversion units 33 and 34, respectively. . Also, as described above, the adjacent angle between the two magnetoelectric conversion elements 21 and 22 adjacent in the circumferential direction is θ / 2, and the rotation of the rotating body 400 output from each of the magnetoelectric conversion elements 21 and 22 The corresponding electrical signal is out of phase by θ / 2. Therefore, the phases of the first pulse signal and the second pulse signal are shifted by a half of the period T _θ (hereinafter, this period is indicated as T _{θ / 2} ). Therefore, the rotation angle signal obtained by superimposing the first pulse signal and the second pulse signal is a pulse signal having a period of _{Tθ / 2} . Since the rotating body 400 is rotating forward, the direction signal is at the Lo level, and since the unevenness 410, 420 passes in front of the magnetoelectric transducer 20, the reference signal is also at the Lo level.

  As described above, the first pulse signal converter 31 converts the output signal of the first magnetoelectric conversion element 21 into the pulse signal having the first pulse width when the rotating body 400 is rotating forward, and the rotating body 400 When the rotation is reversed, the pulse signal is converted into a pulse signal having a second pulse width larger than the first pulse width. As shown in FIG. 4, when receiving the first pulse signal having the second pulse width, the processing unit 200 converts the direction signal from the Lo level to the same pulse signal as the rotation angle signal. As shown in FIG. 7, the period of the pulse signal changes between forward rotation and reverse rotation, but FIG. 4 is not a diagram that takes this into consideration. The same applies to FIG. 6 described later.

  As described above, the second voltage level conversion unit 34 outputs the pulse signal output from the second pulse signal conversion unit 32 to the Lo level and the Hi level when the irregularities 410 and 420 pass in front of the magnetoelectric conversion element 20. When the missing tooth passes in front of the magnetoelectric conversion element 20, it is converted into a pulse signal consisting of a Mid level and a Hi level. As illustrated in FIG. 5, when the processing unit 200 receives the second pulse signal composed of the Mid level and the Hi level, the processing unit 200 raises one pulse to the Lo level reference signal.

  4 and 5, as shown in FIG. 6, when receiving the first pulse signal having the second pulse width, the processing unit 200 changes the direction signal from the Lo level to the same pulse signal as the rotation angle signal. Convert. When the processing unit 200 receives the second pulse signal composed of the Mid level and the Hi level, the processing unit 200 raises one pulse to the Lo level reference signal.

  Next, functions and effects of the rotation angle sensor 100 and the rotation angle detection system 300 according to the present embodiment will be described. As described above, the adjacent angle between two adjacent magnetoelectric transducers 21 and 22 is θ / 2. Therefore, when the rotating body 400 rotates by the adjacent angle θ, the one unevenness 410, 420 rotates by the adjacent angle θ, and the pulse signals corresponding to the one unevenness 410, 420 are obtained from the magnetoelectric transducers 21, 22, respectively. Moreover, since the adjacent angle of the magnetoelectric conversion elements 21 and 22 is θ / 2 as described above, pulse signals different in phase by θ / 2 can be obtained from the adjacent magnetoelectric conversion elements 21 and 22, respectively. Therefore, when these plurality of pulse signals (first pulse signal and second pulse signal) are connected to the processing unit 200 via the signal lines 151 and 152, the pulses included in each pulse signal are sequentially input to the processing unit 200. . Thereby, although the adjacent angle of the convex part 410 is θ, a pulse signal (rotation angle signal) obtained when the adjacent angle of the convex part 410 is θ / 2 is obtained. As described above, by increasing the number of the magnetoelectric conversion elements 20, it is possible to obtain a rotation angle signal having a narrow pulse cycle even when the adjacent angle of the convex portion 410 is wide. That is, a pulse signal having a narrow pulse period can be obtained regardless of the shape of the rotating body (400). Further, as described above, since a plurality of pulse signals whose phases are shifted by θ / n are sequentially input, it is possible to suppress the collapse of the pulses included in each pulse signal. Thereby, the rotation angle of the rotating body 400 is detected at a pitch narrower than the adjacent interval between the convex portions 410.

Independent signal lines 151 and 152 corresponding to the magnetoelectric conversion elements 21 and 22 are connected to the processing unit 200. Thus, the pulse signal adjacent angle is theta convex portion 410 to the signal lines 151 and 152 (first pulse signal and second pulse signal of period T _theta) is input. Therefore, since the pulse density is coarser than the configuration in which the pulse signal with the adjacent angle of the convex portion 410 being θ / 2 is input to each of the signal lines 151 and 152, the noise resistance of the pulse signal is enhanced.

  When the rotating body 400 is rotating forward, the first pulse signal conversion unit 31 converts the output signal of the first magnetoelectric conversion element 21 into a pulse signal having the first pulse width, and when the rotating body 400 is rotating reversely. , And converted into a pulse signal having a second pulse width larger than the first pulse width. Thereby, it is possible to determine whether the rotating body 400 is rotating forward or backward based on the pulse width.

  As shown in FIG. 7, the rotation speed of the rotating body 400 is slower in the case of reverse rotation than in the case of normal rotation, so that the pulse period becomes longer. Therefore, as described above, even if the pulse width of the first pulse signal is converted to the second pulse width wider than the first pulse width during the reverse rotation, the pulse density is suppressed from being reduced, and the pulse included in the pulse signal Is prevented from being crushed. Moreover, it is suppressed that the noise tolerance of a 1st pulse signal is impaired.

  The second voltage level conversion unit 34 converts the pulse signal output from the second pulse signal conversion unit 32 into a pulse signal composed of Lo level and Hi level when the irregularities 410 and 420 pass in front of the magnetoelectric conversion element 20. When the missing tooth passes in front of the magnetoelectric conversion element 20, it is converted into a pulse signal composed of a Mid level and a Hi level. Thereby, the reference position of the rotation angle of the rotating body 400 can be determined based on the voltage level.

  The adjacent interval between the magnetoelectric conversion elements 21 and 22 is equal to θ / n, and the natural number n is equal to the number of the magnetoelectric conversion elements 21 and 22 and is 2. Thereby, unlike the configuration in which the natural number n is different from the number of the magnetoelectric conversion elements 21 and 22, the correspondence between the adjacent interval of the convex portion 410 and the pulse interval becomes clear.

  In the present embodiment, the first pulse signal and the second pulse signal for detecting the rotation angle are input to the signal lines 151 and 152, respectively. Information (pulse width) for detecting the rotation direction is overlapped with the first pulse signal, and information (voltage level) for detecting the reference position of the rotation angle is overlapped with the second pulse signal. . Accordingly, a signal line for inputting the above-described electrical signal including information for detecting the rotation direction or an electrical signal including information for detecting the reference position of the rotation angle to the processing unit 200 is provided. It is unnecessary. As a result, the rotation angle detection system 300 according to the present embodiment has a reduced number of parts compared to the configuration having a signal line for inputting each electrical signal to the processing unit 200 described above.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

In the present embodiment, the rotation angle sensor 100 includes the conversion unit 30 and the magnetoelectric conversion element 20 is connected to the signal line 150 via the conversion unit 30. However, the rotation angle sensor 100 does not have to include the conversion unit 30, and a configuration in which the magnetoelectric conversion element 20 is directly connected to the signal line 150 can also be adopted. Also in this modification, the period signal T _theta (triangular wave) is input to the signal line 150, the noise immunity of the signal is stronger. In the case of this modification, the function of the conversion unit 30 is performed by the processing unit 200.

The rotation angle sensor 100 according to the present embodiment has been described as an example having two magnetoelectric conversion elements 21 and 22 as the magnetoelectric conversion element 20. However, the number of the magnetoelectric conversion elements 20 is not limited to the above example and may be plural. For example, as illustrated in FIG. 8, the rotation angle sensor 100 may have a configuration including four magnetoelectric conversion elements 21 to 24. In this modification, adjacent angles of magnetoelectric conversion elements 21 to 24 has a theta / 4, as shown in FIG. 9, the rotation angle signal of the pulse period is one-quarter of T _θ T _{θ / 4} It becomes. Thus, by increasing the number of magnetoelectric transducers 20, the number of pulses of the rotation angle signal included per pulse period _Tθ is increased. Therefore, based on this rotation angle signal, the rotating body 400 can be controlled with high accuracy. The magnetoelectric conversion elements 21 to 24 are connected to the processing unit 200 via the corresponding signal lines 151 to 154, but the signal lines 153 and 154 are not shown.

  In the present embodiment, the determination unit 35 outputs an instruction signal to the first pulse signal conversion unit 31 so as to convert the pulse width of the first pulse signal in order to include information for detecting the rotation direction. Indicated. However, for example, as illustrated in FIG. 10, when the conversion unit 30 includes the switch 36 and the backflow prevention element 37, the pulse width is not converted, but the opening and closing of the switch 36 is controlled, and the first pulse signal conversion unit 31 By changing the input electrical signal, it is possible to discriminate between normal rotation and reverse rotation of the rotating body 400, and such a configuration may be adopted. In the modification shown in FIG. 10, the first wiring that connects the first magnetoelectric conversion element 21 and the first pulse signal conversion unit 31, and the second wiring that connects the second magnetoelectric conversion element 22 and the second pulse signal conversion unit 32. A relay line is connected between the two lines, and a switch 36 and a backflow prevention element 37 are provided on the relay line. The switch 36 functions to control the connection between the first wiring and the second wiring, and the backflow prevention element 37 suppresses the electrical signal from the first magnetoelectric conversion element 21 from flowing into the second pulse signal conversion unit 32. Fulfills the function. When the determination unit 35 determines that the rotating body 400 is rotating forward, the determination unit 35 does not input an instruction signal to the switch 36 and puts the switch 36 into a non-driven state. On the other hand, when the determination unit 35 determines that the rotating body 400 is reversely rotated, the determination unit 35 inputs an instruction signal to the switch 36 and sets the switch 36 to a driving state. As a result, the electrical signals of the magnetoelectric transducers 21 and 22 are input to the first pulse signal converter 31 during reverse rotation, and a signal in which the first pulse signal and the second pulse signal are superimposed is input to the first signal line 151. Is done. When the processing unit 200 receives this signal, the processing unit 200 determines that the rotating body 400 is reversed, and makes the direction signal the same as the rotation angle signal (see FIG. 11). The determination unit 35, the switch 36, and the backflow prevention element 37 constitute a switching unit described in the claims.

  In the modification shown in FIG. 10, when the determination unit 35 determines that the rotation is reversed, the determination unit 35 outputs an instruction signal to the first pulse signal conversion unit 31 so that the pulse width of the pulse signal is the second pulse width. Also good. In this case, as shown in FIG. 12, the pulses included in the pulse signal input to the first signal line 151 are dense. However, as described above, the case of reverse rotation and the case of normal rotation are compared. This increases the pulse period. Therefore, even if the first pulse signal and the second pulse signal are superimposed on the first signal line 151 as described above, the superimposed pulse signal is suppressed from being weakened by noise.

  In the present embodiment, an example is shown in which the pulse width of the first pulse signal is adjusted when the rotation is reversed. However, the reverse pulse may be configured by adjusting the voltage level of the first pulse signal. Specifically, for example, as shown in FIG. 13, during forward rotation, the voltage level of the first pulse signal is set to Lo level and Hi level, and during reverse rotation, the voltage level of the first pulse signal is set to Lo level and Mid level. To do. More specifically, each of the voltage level conversion units 33 and 34, when the rotating body 400 is rotating forward, converts all of the pulse signals output from the pulse signal conversion units 31 and 32 to the Lo level and the Hi level. Is converted to a pulse signal having a voltage level of The first voltage level conversion unit 33 converts the pulse signal output from the first pulse signal conversion unit 31 into a pulse signal composed of a Mid level and a Hi level when the rotator 400 is reversely rotated.

  Also in this configuration, as shown in FIG. 14, the electric signals of the magnetoelectric conversion elements 21 and 22 are input to the first pulse signal conversion unit 31 during the reverse rotation, and the first pulse signal and the second pulse signal are superimposed. A configuration (configuration shown in FIG. 10) in which the processed signal is input to the first signal line 151 can also be adopted. Also in this configuration, the pulse width may be adjusted as shown in FIG. Such a configuration is realized by combining the above-described configurations. Since each configuration is described in detail, the description thereof is omitted.

  In the present embodiment, the rotating body 400 shows an example in which the first member 410 having the convex portion formed on the surface and the second member 420 having the concave portion are alternately connected along the rotation direction. . However, the rotating body 400 may employ a configuration in which the first member 410 having a concave portion on the surface and the second member 420 having a convex portion are alternately connected along the rotation direction. it can. Further, as shown in FIG. 16, the rotating body 400 includes a first member 410 having a first magnetic pole (N pole) and a second member 420 having a second magnetic pole (S pole) along the rotation direction. Thus, it is possible to employ a configuration in which the two are alternately connected. In this case, since the magnetic flux is generated from the rotator 400, the rotation angle sensor 100 does not need to have the magnetic field generator 10. The magnetoelectric conversion element 20 converts the fluctuation of the rotating magnetic flux emitted from the rotating body 400 into an electric signal.

DESCRIPTION OF SYMBOLS 10 ... Magnetic field generation part 21-24 ... Magnetoelectric conversion element 100 ... Rotation angle sensor 151-154 ... Signal line 200 ... Processing part 400 ... Rotating body

Claims (9)

A rotation angle sensor for detecting a rotation angle of the rotating body based on a rotating magnetic flux generated by the rotation of the rotating body (400),
A plurality of magnetoelectric transducers (21 to 24) for converting fluctuations of the rotating magnetic flux due to rotation of the rotating body into electrical signals;
The rotating body includes a first member (410) and a second member (420) that are alternately connected along a rotation direction so that the rotating magnetic flux periodically fluctuates. Are arranged at equal intervals along the rotation direction,
The adjacent angle formed by two lines connecting each of the two adjacent magnetoelectric transducers and the rotation center (RC) of the rotating body is adjacent to each other via one second member, where n is a natural number of 2 or more. When an adjacent angle formed by two lines connecting each of the two first members and the rotation center is θ, the adjacent angle θ is equal to a value θ / n obtained by dividing the adjacent angle θ by a natural number n.
An independent signal line (151 to 154) corresponding to each of the plurality of magnetoelectric conversion elements is connected to a processing unit (200) that processes an output signal of the magnetoelectric conversion element. The rotating body has a property of rotating forward in one direction of the rotation direction and reverse in the reverse direction of the one direction, and the length of the rotation direction is longer than each of the first member and the second member. Having a third member,
A plurality of pulse signal converters (31, 32) corresponding to each of the plurality of magnetoelectric conversion elements and converting each output signal into a pulse signal;
A plurality of voltage level converters (33, 34) corresponding to each of the plurality of pulse signals and converting the respective voltage levels;
A determination unit (35) that determines a reference position of a rotation direction and a rotation angle of the rotating body based on output signals of the plurality of magnetoelectric transducers,
The rotation angle sensor according to claim 1, wherein a plurality of the pulse signals output from the voltage level conversion unit are input to a plurality of the corresponding signal lines.   The pulse signal conversion unit converts the output signals of the plurality of magnetoelectric conversion elements into pulse signals having a first pulse width when the rotating body is rotating forward, and when the rotating body is reversed, 3. The processing unit converts an output signal of the magnetoelectric conversion element used for detection of the rotation direction of the rotating body into a pulse signal having a second pulse width different from the first pulse width. The rotation angle sensor described in 1. The rotational speed of the rotating body is faster in the case of normal rotation than in the case of reverse rotation,
The rotation angle sensor according to claim 3, wherein the second pulse width is larger than the first pulse width.   The voltage level conversion unit converts all of the plurality of pulse signals into a pulse signal composed of a voltage level of a first level and a second level when the rotating body is rotating forward, and the rotating body is reversed. A voltage level conversion unit that converts the pulse signal used for detecting the rotation direction of the rotating body into a pulse signal composed of a third level and the second level in the processing unit. The rotation angle sensor of any one of Claims 2-4.   When the rotating body is rotating forward, an output signal of the corresponding magnetoelectric conversion element is output to each of the plurality of signal lines, and when the rotating body is rotating reversely, the processing unit causes the rotating body to rotate. 6. The rotation angle sensor according to claim 2, further comprising: a switching unit that superimposes output signals of the plurality of magnetoelectric conversion elements on the signal line used for detecting the rotation direction of the magnetic field.   The voltage level conversion unit converts the pulse signal into a pulse signal composed of a voltage level of a first level and a second level when the rotating body is rotating forward or reversely, and the rotating body is a reference for a rotation angle. A voltage level conversion unit for converting the pulse signal used for detecting the reference position of the rotation angle of the rotating body into a pulse signal composed of a third level and the second level when the processing unit reaches the position; The rotation angle sensor according to any one of claims 2 to 6.   The rotation angle sensor according to claim 1, wherein the natural number n is the same as the number of the plurality of magnetoelectric transducers. The rotation angle sensor according to any one of claims 1 to 8, a processing unit (200) for processing an output signal of the magnetoelectric transducer (21 to 24), and a plurality of the magnetoelectric transducers, respectively. A rotation angle detection system having signal lines (151 to 154) connected to the processing unit independently of each other,
The processing unit detects a rotation angle signal by superimposing output signals of the plurality of magnetoelectric conversion elements, and based on the rotation angle signal, the rotation angle of the rotating body is narrower than the adjacent angle θ. A rotation angle detection system characterized by detecting.

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