JP2012198067A - Motion detection device for detecting rotational motion or revolving motion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve reductions in size, weight and cost of a motion detection device, which counts rotational frequency or the like of a detection body with no power source, without decreasing accuracy of detecting rotational frequency or the like of the detection object.SOLUTION: A motion detection device has: stand-by magnets 15 and 17 as well as an output magnet 16 arranged in a circumferential direction at intervals Da on outer peripheral portion of a movable section 13 which rotates; and magnetic sensors 1, 2 and 3 around the movable section 13 at wider intervals Db than the interval Da. When the stand-by magnets 15 and 17 pass near either of the magnet sensors 1, 2 and 3 while the movable section 13 is rotated in tandem with rotation of a rotational axis 150, the magnet sensor comes into a stand-by state. When the output magnet 16 passes near the magnet sensor which is in the stand-by state, a large Barkhausen effect is produced at a magnetic element 21 of the magnetic sensor and a coil 22 outputs a detection signal. Rotational frequency of the rotational axis 150 is counted based on the detection signal.

Description

  The present invention relates to a motion detection device that detects the rotational motion or circular motion of an object using magnetism.

  2. Description of the Related Art There are known devices that change a magnetic field according to the movement of an object and generate an electric signal according to the movement of the object by using an electromotive force generated thereby.

  For example, in Patent Document 1 below, an array body in which a magnetic field detection unit in which a coil is wound around a magnetic element that generates a large Barkhausen effect and two types of magnets in which the arrangement of magnetic poles is opposite to each other are alternately arranged The magnetic field detector is fixed, and the array is configured to reciprocate in the vicinity of the magnetic field detector, thereby changing the magnetization direction of the magnetic element, and the electromotive force generated thereby An apparatus for generating a pulse signal using it is described.

  Further, in Patent Document 2 below, a magnetic field detection unit in which a coil is wound around a magnetic element that generates a large Barkhausen effect is arranged so as not to move in the vicinity of the rotation axis. Two types of magnets opposite to each other are attached, and each magnet is rotated in accordance with the rotation of the rotation shaft, thereby changing the magnetization direction of the magnetic element, and using the electromotive force generated thereby, a pulse signal An apparatus for generating is described.

  Patent Document 3 below includes a magnetic field detection unit in which a coil is wound around a magnetic element that generates a large Barkhausen effect, and processing is performed using electric power generated by a pulse voltage output from the magnetic field detection unit. An apparatus for operating a circuit is described.

  Further, in Patent Document 4 below, a pair of hard magnetic bodies that are provided in a circumferential direction on a rotating body that is rotatably supported and that has an N-pole and an S-pole, It is generated from four power generation type magnetic field detection units that generate a pulse voltage having a phase difference of 90 degrees magnetically by a hard magnetic material, a predetermined number of other magnetic field detection units, and the power generation type magnetic field detection unit. Counting means that is driven by a pulse voltage, counts and adds / subtracts the number of pulse voltages based on the rotation direction to generate and store a count value according to the rotation area, the rotation area based on the count value, and the other magnetic field detection unit Describes a device including a rotation angle detector that detects an absolute rotation angle based on the magnetic period output from.

JP 11-195964 A JP 2001-194182 A JP 2009-15683 A JP 2009-162730 A

  Any of the devices described in Patent Documents 1 to 4 described above can generate an electrical signal using an electromotive force generated by a change in a magnetic field according to the movement of an object. It is not necessary to supply power from a power source in order to perform processing using an electrical signal. Therefore, the above-described device can be used as a non-powered detection device that detects the movement of the movable part of the device while the device is powered off.

  For example, when an industrial robot installed in a factory where factory automation is installed is turned off, when the movable part of the robot is moved by some external force, the movement of the movable part is detected by a non-powered detection device. The detection data indicating the movement is stored in the memory, and then the robot has been moved by some external force using the detection data stored in the memory when the robot is powered on. A process of automatically recognizing the position of the movable part of the robot can be realized.

  Here, in order to examine a non-power supply motion detection device that detects the rotational motion of a movable part in a device such as a robot as described above, the motion detection device is not supplied with power from the power source. It is necessary to provide as a basic function a function of counting the number of rotations in consideration of the rotation direction (for example, +1 rotation when rotating once in the right direction and -1 rotation when rotating once in the left direction). is there.

  Furthermore, it is desirable for the motion detection device to reduce the size, weight, and cost of the motion detection device without impairing the accuracy of detection of the rotational speed in consideration of the rotation direction of the movable part.

  Specifically, regarding the accuracy of detection of the rotational speed in consideration of the rotational direction of the movable part, the rotational direction is reversed without the movable part rotating once while the movable part performs rotational motion. Even when repeated motions are often performed, it is desirable to accurately detect the number of rotations in consideration of the direction of rotation of the movable part without losing sight of the rotational state of the movable part.

  On the other hand, to reduce the size, weight, and cost of the motion detector, the number of magnetic field detectors is reduced to the minimum number that can reliably detect the rotational direction of the movable part, that is, three. It is desirable to realize a configuration that can Note that the configuration that can reduce the number of magnetic field detection units to a minimum of three is applicable to a motion detection device including three magnetic field detection units and a motion including four or more magnetic field detection units. It includes the meaning of a configuration that can also be applied to a detection device.

  Even when the movable part performs a repetitive reversal of the rotation direction without making one rotation, a motion detection capable of detecting an accurate number of rotations considering the rotation direction of the movable part with a minimum of three magnetic field detectors. The device is not described in any of Patent Documents 1 to 4. In addition, it is not easy to realize such a motion detection device based on the above-mentioned Patent Documents 1 to 4 or other known techniques.

  Furthermore, in the motionless device of the non-power source that detects the rotational motion of the movable part, the power required for counting the number of rotations considering the rotational direction of the movable part (generated from the signal output from the magnetic field detection unit) It is desirable to realize a configuration that reduces power consumption. In this respect as well, there is no description or suggestion in Patent Documents 1 to 4, and the realization thereof is not easy.

  It should be noted that the non-power source motion detection device that detects the circular motion of the movable part in equipment such as an industrial robot and a belt conveyor is also desired to be the same as the above-described non-power source motion detection device that detects the rotational motion.

  The present invention has been made in view of the above-described problems, for example, and a first object of the present invention is to perform rotation in consideration of the rotation direction of a detected object such as a movable part of a device without supplying power from a power source. A motion detection device that can count the number of laps in consideration of the number or circulatory movement direction, and the accuracy of detection of the number of laps in consideration of the rotation number or the circulatory movement direction in consideration of the rotation direction of the detected object. An object of the present invention is to provide a motion detection device that can be reduced in size, weight, and cost without loss.

  A second object of the present invention is to provide a motion detection apparatus capable of counting the number of rotations considering the rotation direction or the rotation direction of the object to be detected without supplying power from the power source. An object of the present invention is to provide a motion detection device capable of reducing power consumption necessary for counting the number of rotations considering the rotation direction of the detected object or the number of rotations considering the direction of circular movement.

  In order to solve the above-described problem, a first motion detection device of the present invention is a motion detection device that detects a rotational motion or a circular motion of a detected object, and according to the rotational motion or the circular motion of the detected object. A movable part that rotates or revolves, a first magnetic field generating part that generates a first magnetic field in which the direction of the magnetic field is the first direction, and a second that is opposite to the first direction. When the first magnetic field generator approaches the second magnetic field generator that generates the second magnetic field that is the direction of the first magnetic field, the second magnetic field generator is magnetized in the first direction by the first magnetic field, Due to the electromotive force that is magnetized in the second direction by the second magnetic field when the magnetic field generator approaches, and the magnetization direction changes between the first direction and the second direction. At least three magnetic field detectors for outputting generated detection signals; and A motion detection circuit that detects a state of rotational motion or circular motion of the detected object based on a detection signal output from the magnetic field detection unit, and the first magnetic field generation unit and the second magnetic field generation unit include: The outer peripheral part of the movable part is arranged at a predetermined interval in the circumferential direction, and the at least three magnetic field detecting parts are in the vicinity of the outer peripheral part of the movable part, and the movable part is rotated or circularly moved. It is arranged with an interval larger than the predetermined interval so as to follow the trajectory of the outer peripheral portion of the movable portion.

  According to the first motion detection device of the present invention, since the arrangement interval between the first magnetic field generation unit and the second magnetic field generation unit is smaller than the arrangement interval of the magnetic field detection unit, the detection target does not rotate once. Even when performing a motion that repeatedly reverses the rotation direction, the accurate number of rotations considering the rotation direction of the detected object can be detected by a minimum of three magnetic field detectors. Therefore, it is possible to reduce the size, weight, and cost of the motion detection device without impairing the accuracy of detection of the rotational speed in consideration of the rotation direction of the detection target.

  This will be specifically described. For convenience of explanation, (a) the first magnetic field generating unit and the second magnetic field generating unit are arranged clockwise (clockwise) at a predetermined interval on the outer periphery of the movable unit in this order, and (b) the movable unit The three magnetic field detectors A, B, and C are rotated clockwise in this order from the predetermined interval so as to follow the locus of the outer peripheral portion of the movable portion when the movable portion rotates. (C) The movable part rotates in the right direction. (D) In the initial state, the magnetization direction of each of the magnetic field detectors A, B, and C is the first direction. (E) Each magnetic field detection unit A, B, C is assumed to be a motion detection device that outputs a detection signal when the direction of magnetization changes from a first direction to a second direction.

  In such a motion detection device, when the operation of the movable part rotating once in the right direction from the initial state is observed with the rotational motion of the detected object, for example, first, the second magnetic field generation unit becomes the magnetic field detection unit A. , The direction of magnetization of the magnetic field detector A changes from the first direction to the second direction, and a detection signal is output from the magnetic field detector A. Subsequently, the first magnetic field generation unit passes in the vicinity of the magnetic field detection unit A, and the magnetization direction of the magnetic field detection unit A returns from the second direction to the first direction. Thereafter, the second magnetic field generator passes near the magnetic field detector B, the magnetization direction of the magnetic field detector B changes from the first direction to the second direction, and a detection signal is output from the magnetic field detector B. Is done. Subsequently, the first magnetic field generation unit passes in the vicinity of the magnetic field detection unit B, and the magnetization direction of the magnetic field detection unit B returns from the second direction to the first direction. Thereafter, the second magnetic field generation unit passes near the magnetic field detection unit C, the direction of magnetization of the magnetic field detection unit C changes from the first direction to the second direction, and a detection signal is output from the magnetic field detection unit C. Is done. Subsequently, the first magnetic field generation unit passes in the vicinity of the magnetic field detection unit C, and the magnetization direction of the magnetic field detection unit C returns from the second direction to the first direction.

  The point to be noted in this operation is that the second magnetic field generation unit starts moving from a position near one of the three magnetic field detection units A, B, and C by the rotation of the movable unit. This is a point in which the magnetization direction of the one magnetic field detection unit always returns to the first direction when reaching a position near another magnetic field detection unit arranged next to the one magnetic field detection unit. As a result, the magnetization directions of two magnetic field detection units (generally, (k-1) magnetic field detection units out of k magnetic field detection units) out of the three magnetic field detection units A, B, and C are always set. The direction is the first direction, and the detection signal can be output when the second magnetic field generator approaches in the future. As a result, even when the object to be detected performs a repetitive reversal of the rotation direction without making one rotation, as long as the second magnetic field generation unit moves between two adjacent magnetic field detection units, at least A detection signal is output from one of the two magnetic field detection units. Therefore, it is possible to always accurately grasp the rotation state of the detected object.

  For the same reason, according to the first motion detection device of the present invention, the arrangement interval between the first magnetic field generation unit and the second magnetic field generation unit is smaller than the arrangement interval of the magnetic field detection unit. Even when the movable part performs a motion that repeats the reversal of the circumferential movement direction without making one round, the accurate number of rounds considering the circumferential movement direction of the movable part can be detected by a minimum of three magnetic field detection units. Therefore, the motion detection device can be reduced in size, weight, and cost without impairing the accuracy of detection of the number of rotations in consideration of the direction of rotation of the detection target.

  In order to solve the above-mentioned problem, a second motion detection device of the present invention is a motion detection device that detects a rotational motion or a circular motion of a detected object, and according to the rotational motion or the circular motion of the detected object. A movable part that rotates or revolves, a first magnetic field generating part that generates a first magnetic field in which the direction of the magnetic field is the first direction, and a second that is opposite to the first direction. When the first magnetic field generator approaches the second magnetic field generator that generates the second magnetic field that is the direction of the first magnetic field, the second magnetic field generator is magnetized in the first direction by the first magnetic field, Due to the electromotive force that is magnetized in the second direction by the second magnetic field when the magnetic field generator approaches, and the magnetization direction changes between the first direction and the second direction. At least three magnetic field detectors for outputting generated detection signals; and A motion detection circuit that detects a state of rotational motion or circular motion of the detected object based on a detection signal output from the magnetic field detection unit, and the first magnetic field generation unit and the second magnetic field generation unit include: The at least three magnetic field detections are arranged in the vicinity of the outer peripheral part of the movable part and at a predetermined interval so as to follow the trajectory of the outer peripheral part of the movable part when the movable part rotates or rotates. The portions are arranged on the outer peripheral portion of the movable portion with a larger interval in the circumferential direction than the predetermined interval.

  Also with the second motion detection device of the present invention, the same effect as the first motion detection device of the present invention can be obtained.

  In order to solve the above problems, a third motion detection device of the present invention is the above-described first or second motion detection device of the present invention, in which each magnetic field detection unit is a magnetic element that produces a large Barkhausen effect. And a coil wound around the magnetic element.

  According to the third motion detection device of the present invention, the detection signal output from each magnetic field detection unit can be a pulse signal. Therefore, the detection processing by the motion detection circuit can be facilitated or highly accurate.

  In order to solve the above problems, a fourth motion detection device of the present invention is the above-described motion detection device of any one of the first to third of the present invention, based on detection signals output from the magnetic field detection units. A power supply voltage generation circuit for generating a power supply voltage is provided, and the motion detection circuit is operated by the power supply voltage generated by the power supply voltage generation circuit.

  According to the fourth motion detection device of the present invention, it is possible to realize a motion detection device with no power supply.

  In order to solve the above problems, a fifth motion detection device of the present invention is the motion detection device according to any one of the first to fourth of the present invention described above, wherein the motion detection circuit is connected to each magnetic field detection unit. A circuit that detects a state of rotational motion of the detected object based on a detection signal that is output; the motion detection circuit is configured so that the detected object is 1 based on a detection signal output from each of the magnetic field detectors; It is determined whether or not the object has been rotated, and a rotation determination circuit that outputs a rotation determination signal indicating that the object to be detected has rotated once each time the object to be detected has rotated, and is output from the rotation determination circuit. And a counting circuit for counting the number of rotations of the detected object based on a rotation determination signal.

  In the fifth motion detection apparatus of the present invention, the motion detection circuit is divided into a rotation determination circuit and a count circuit, and the count circuit determines the number of rotations of the detected object based on the rotation determination signal output from the rotation determination circuit. With the configuration of counting, the timing when the counting circuit operates can be limited to when the rotation determination signal is output from the rotation determination circuit, that is, when the detected object has made one rotation. Thereby, the period during which the counting circuit operates can be reduced, and power consumption can be reduced.

  In order to solve the above problem, a sixth motion detection device of the present invention is the above-described fifth motion detection device of the present invention, wherein one of the at least three magnetic field detection units is a reference magnetic field. Each of the remaining magnetic field detection units is a non-reference magnetic field detection unit, and the rotation determination circuit detects a detection signal from the previous reference magnetic field detection unit each time a detection signal is output from the reference magnetic field detection unit. Is output from one of the non-reference magnetic field detection units immediately before the detection signal is output from the non-reference magnetic field detection unit and the detection signal is output from the reference magnetic field detection unit this time. It is determined whether each detected signal is a predetermined detection signal, and based on the determination result, it is determined whether the detected object has made one revolution.

  According to the rotation determination circuit of the sixth motion detection device of the present invention, by storing two types of detection signals and determining whether or not each of the two types of detection signals is a predetermined detection signal. It can be determined whether or not the detected object has made one rotation. Accordingly, the number of processes and the amount of information stored in the rotation determination circuit can be reduced, and power consumption can be reduced.

  In order to solve the above-described problem, the seventh motion detection device of the present invention is the above-described fifth motion detection device of the present invention, wherein the rotation determination circuit outputs a detection signal from each of the magnetic field detection units. Each time, the detection signal output this time is compared with the detection signal output last time, the amount of rotation of the detection target is detected based on the comparison result, and the detection target is detected based on the rotation amount of the detection target. It is characterized by determining whether or not the detection body has made one rotation.

  According to the rotation determination circuit of the seventh motion detection device of the present invention, one detection signal and the rotation amount may be stored as information used for determining whether or not the detected object has made one rotation. Therefore, each detection signal output from each magnetic field detection unit is stored and held, and compared with other rotation determination circuits that determine whether or not the detected object has made one rotation based on these detection signals. The amount of information stored can be reduced, and the power consumption can be reduced. In consideration of the case where the movable part repeats reversal of the rotation direction without making one rotation, the other rotation determination circuit uses a magnetic field as information used for determining whether or not the detected object has made one rotation. It is necessary to store and simultaneously store information exceeding the number of detection units.

  In order to solve the above-described problem, an eighth motion detection device according to the present invention is the motion detection device according to any one of the fifth to seventh inventions described above, wherein the counting circuit is output from the rotation determination circuit. A count processing unit that counts the number of rotations of the detected object based on the rotation determination signal and outputs a count value indicating the number of rotations of the detected object in gray code; and from the count processing unit in gray code And a count value storage unit for storing the output count value.

  According to the eighth motion detection device of the present invention, the count value is stored in the Gray code, so that the number of storage processes can be reduced and the power consumption can be reduced.

  According to the present invention, in the motion detection device capable of counting the number of rotations considering the rotation direction of the detection object or the number of rotations considering the rotation movement direction without supplying power from the power source, The motion detection device can be reduced in size, weight, and cost without impairing the accuracy of detection of the number of rotations taking into account the rotation direction or the number of rotations taking into account the direction of rotation.

  Further, according to the present invention, in the motion detection apparatus capable of counting the number of rotations considering the rotation direction of the detection object or the number of rotations considering the rotation direction, the rotation considering the rotation direction of the detection object It is possible to reduce power consumption necessary for counting the number of laps considering the number or the lap movement direction.

It is a front view which shows the rotation detection apparatus by the 1st Embodiment of this invention. It is sectional drawing which shows the rotation detection apparatus by the 1st Embodiment of this invention seen from the arrow II-II direction in FIG. It is explanatory drawing which shows the arrangement | positioning relationship of each standby magnet, output magnet, and each magnetic sensor provided in the inside of the rotation detection apparatus by the 1st Embodiment of this invention. It is a block diagram which shows the structure of the circuit unit in the rotation detection apparatus by the 1st Embodiment of this invention. It is explanatory drawing which shows operation | movement of the circuit unit according to a 1st algorithm in the rotation detection apparatus by the 1st Embodiment of this invention. It is explanatory drawing which shows the processing content of the circuit unit according to a 1st algorithm, the value before and behind a process, etc. in the rotation detection apparatus by the 1st Embodiment of this invention. It is a block diagram which shows the structure of the circuit unit in the rotation detection apparatus by the 2nd Embodiment of this invention. It is explanatory drawing which shows operation | movement of the circuit unit according to a 2nd algorithm in the rotation detection apparatus by the 2nd Embodiment of this invention. It is explanatory drawing which shows the processing content of the circuit unit according to a 2nd algorithm, the value before and behind a process, etc. in the rotation detection apparatus by the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the circuit unit in the rotation detection apparatus by the 3rd Embodiment of this invention. It is explanatory drawing which shows operation | movement of the circuit unit according to a 3rd algorithm in the rotation detection apparatus by the 3rd Embodiment of this invention. It is explanatory drawing which shows the processing content of the circuit unit according to a 3rd algorithm, the value before and behind a process, etc. in the rotation detection apparatus by the 3rd Embodiment of this invention. It is a block diagram which shows the structure of the circuit unit in the rotation detection apparatus by the 4th Embodiment of this invention. It is explanatory drawing which shows operation | movement of the circuit unit according to the 4th algorithm in the rotation detection apparatus by the 4th Embodiment of this invention. It is explanatory drawing which shows the processing content of the circuit unit according to the 4th algorithm, the value before and behind a process, etc. in the rotation detection apparatus by the 4th Embodiment of this invention. It is explanatory drawing which shows other embodiment of this invention. It is explanatory drawing which shows other embodiment of this invention. It is sectional drawing which shows other embodiment of this invention. It is sectional drawing which shows other embodiment of this invention. It is explanatory drawing which shows other embodiment of this invention.

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

(First Embodiment: Configuration of Rotation Detection Device)
First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a rotation detection device according to a first embodiment of the present invention, and FIG. 2 shows a cross section of the rotation detection device viewed from the direction of arrows II-II in FIG. In FIG. 1, a rotation detection device 100, which is a first embodiment of the motion detection device of the present invention, is a device that detects the rotational motion of a detected object, specifically, the number of rotations in consideration of the direction of rotation. The rotation detection device 100 can detect the rotational motions of various detected objects. In the present embodiment, a rotation shaft 150 of a servo motor provided in a movable part of an industrial robot is taken as an example of a detected object.

  The rotation detection device 100 includes a casing 11 that is formed in a covered cylindrical shape using, for example, resin. The casing 11 is formed with an insertion hole 12 through which the rotary shaft 150 is rotatably inserted. The casing 11 is attached and fixed to an industrial robot via an attachment member (not shown), for example.

  A movable portion 13 is provided in the casing 11. The movable part 13 is formed in a cylindrical shape with, for example, resin. A mounting hole 14 is formed in a portion corresponding to the central axis of the movable portion 13, and the movable portion 13 is mounted on the rotating shaft 150 by passing the rotating shaft 150 through the mounting hole 14. The movable portion 13 is fixed to the rotation shaft 150 and rotates together with the rotation shaft 150.

  Three magnets 15, 16, and 17 are provided on the outer peripheral portion of the movable portion 13. Of the magnets 15, 16, and 17, the magnets 15 and 17 disposed on the right side and the left side are first magnetic field generation units that generate a first magnetic field whose magnetic field direction is the first direction. As will be described later, the magnets 15 and 17 are magnets that place the magnetic sensors 1, 2, and 3 in a standby state. Hereinafter, the first magnetic field is referred to as a “standby magnetic field”, and the magnets 15 and 17 are referred to as “standby magnets”, respectively. Each of the standby magnets 15 and 17 is fixed inside the movable portion 13 so that the near side in FIG. 1 is the south pole and the far side is the north pole.

  The magnet 16 disposed between the standby magnet 15 and the standby magnet 17 generates a second magnetic field that generates a second magnetic field having a second direction opposite to the first direction. Part. As will be described later, the magnet 16 is a magnet that puts the magnetic sensors 1, 2, and 3 into an output state. Hereinafter, the second magnetic field is referred to as an “output magnetic field”, and the magnet 16 is referred to as an “output magnet”. The output magnet 16 is fixed inside the movable portion 13 so that the front side in FIG. 1 is an N pole and the back side is an S pole.

  In the casing 11, three magnetic sensors 1, 2, and 3 are provided in a region around the movable portion 13 and in the vicinity of the outer peripheral portion of the movable portion 13. Each of the magnetic sensors 1, 2, and 3 includes a magnetic element 21 that generates a large Barkhausen effect and a coil 22 wound around the magnetic element 21.

  A composite magnetic wire is used for the magnetic element 21 of each of the magnetic sensors 1, 2, and 3. In general, a composite magnetic wire is a thin wire-like ferromagnetic material. The composite magnetic wire has a unique magnetism in which the direction of magnetization changes when a relatively small external magnetic field is applied to the outer periphery, but the direction of magnetization does not change unless a relatively large external magnetic field is applied to the center. It is a uniaxial anisotropic composite magnetic material having characteristics. When a relatively large external magnetic field sufficient to reverse the magnetization direction of the center portion of the composite magnetic wire is applied in one direction parallel to the longitudinal direction of the composite magnetic wire, the magnetization direction of the center portion of the composite magnetic wire And the direction of magnetization of the outer peripheral portion are aligned in the same direction. After that, the outside is relatively small enough to reverse only the magnetization direction of the outer periphery of the composite magnetic wire in another direction that is parallel to the longitudinal direction of the composite magnetic wire and opposite to the one direction. When a magnetic field is applied, the direction of magnetization at the center of the composite magnetic wire does not change, and only the direction of magnetization at the outer periphery is reversed. As a result, the composite magnetic wire is in a state in which the direction of magnetization differs between the central portion and the outer peripheral portion, and this state is maintained even when the external magnetic field is removed.

  Thus, an external magnetic field is applied to the composite magnetic wire in which the magnetization direction is different between the central portion and the outer peripheral portion in the one direction. At this time, if the strength of the external magnetic field is initially reduced and then the strength of the external magnetic field is gradually increased, a large Barkhausen effect occurs when the strength of the external magnetic field exceeds a certain strength, resulting in a composite The direction of magnetization of the outer periphery of the magnetic wire is rapidly reversed.

  In addition, the magnetic element 21 of each magnetic sensor 1, 2, 3 is not limited to a composite magnetic wire, and various other magnetic elements exhibiting the same behavior can be used. For example, a thin film-like magnetic material as disclosed in JP-A-4-218905 can be used as the magnetic element.

  The outer peripheral portion of the magnetic element 21 (composite magnetic wire) of each of the magnetic sensors 1, 2, and 3 is moved in the first direction by the standby magnetic field when the standby magnet 15 or the standby magnet 17 approaches as the movable portion 13 rotates. The magnetic element 21 is magnetized in the direction opposite to the magnetization direction of the central portion. Thereby, the magnetic element 21 will be in the state from which the direction of magnetization of a center part differs from the direction of magnetization of an outer peripheral part. Here, in each of the magnetic sensors 1, 2, and 3, a state in which the magnetization direction of the central portion of the magnetic element 21 is different from the magnetization direction of the outer peripheral portion is referred to as a “standby state”.

  On the other hand, the outer periphery of the magnetic element 21 of each of the magnetic sensors 1, 2, 3 is moved in the second direction (the same direction as the magnetization direction of the central portion of the magnetic element 21) by the output magnetic field when the output magnet 16 approaches. ) Is magnetized. Thereby, in the magnetic element 21, the magnetization direction in the central part and the magnetization direction in the outer peripheral part are in the same state. Here, in each of the magnetic sensors 1, 2, and 3, the state in which the magnetization direction of the central portion of the magnetic element 21 is the same as the magnetization direction of the outer peripheral portion is referred to as an “output state”.

  When each of the magnetic sensors 1, 2, and 3 changes from the standby state to the output state, a detection signal is output from each of the magnetic sensors 1, 2, and 3. That is, a large Barkhausen effect occurs when the direction of magnetization of the outer peripheral portion of the magnetic element 21 changes from the first direction to the second direction. A detection signal is output.

  In addition, as shown in FIG. 2, each magnetic sensor 1, 2, 3 has one end of the magnetic element 21 supported by the substrate 23 and the other end supported by the wall of the casing 11. It is fixed to. In each of the magnetic sensors 1, 2 and 3, the longitudinal direction of the magnetic element 21 is parallel to the direction of the standby magnetic field generated by the standby magnets 15 and 17 and the direction of the output magnetic field generated by the output magnet 16. It is arranged to be.

  Further, a substrate 23 is provided in the casing 11. The board | substrate 23 is being fixed to the wall part of the casing 11, for example. Further, the substrate 23 is formed in a disc shape, and a hole portion 24 through which the rotary shaft 150 is rotatably penetrated is formed at the center thereof. On the substrate 23, a circuit unit 25 and a connector 26, which will be described later, are provided. The coils 22 of the magnetic sensors 1, 2 and 3 are electrically connected to the circuit unit 25 on the substrate 23. Further, by connecting the cable 27 to the connector 26, the count value stored in the count value storage unit 38 in the circuit unit 25 described later can be output to the outside.

(Relationship between magnet and magnetic sensor)
FIG. 3 shows an arrangement relationship between the standby magnet 15, the output magnet 16, the standby magnet 17 and the magnetic sensors 1, 2, and 3 provided inside the rotation detection device 100. As shown in FIG. 3, the standby magnet 15, the output magnet 16, and the standby magnet 17 are arranged on the outer peripheral portion of the movable portion 13 with a predetermined interval Da in the circumferential direction. That is, the distance Da is between the standby magnet 15 and the output magnet 16 and between the output magnet 16 and the standby magnet 17. On the other hand, each of the magnetic sensors 1, 2, and 3 is in the vicinity of the outer peripheral portion of the movable portion 13 and is predetermined along the locus of the outer peripheral portion of the movable portion 13 when the movable portion 13 rotates around the point P. Are arranged with a distance Db. That is, the distance Db is between the magnetic sensor 1 and the magnetic sensor 2, between the magnetic sensor 2 and the magnetic sensor 3, and between the magnetic sensor 3 and the magnetic sensor 1. The interval Da is smaller than the interval Db. For example, when the distance Db is 120 degrees, the distance Da is about 10 degrees to 110 degrees. In the example shown in FIG. 3, the interval Da is 30 degrees.

  The magnetic sensors 1, 2, and 3 are desirably arranged at equal intervals in the circumferential direction over the entire circumference of the movable part 13 so as to surround the outside of the movable part 13. By arranging the magnetic sensors 1, 2, and 3 in this way, rotation determination processing by the rotation determination circuit 31 described later can be performed easily or with high accuracy. However, the magnetic sensors 1, 2, and 3 need not be arranged at equal intervals in the circumferential direction. Even if the magnetic sensors 1, 2, and 3 are not arranged at equal intervals in the circumferential direction, the rotation determination process by the rotation determination circuit 31 can be performed. However, when the magnetic sensors 1, 2, and 3 are not arranged at equal intervals in the circumferential direction, the interval Da is set to be smaller than the minimum interval among the respective intervals of the magnetic sensors 1, 2, and 3. To do. Further, the magnetic sensors 1, 2, and 3 do not have to be arranged over the entire circumference of the movable part 13, for example, may be arranged in a half of the area surrounding the movable part 13 over the whole circumference. Good.

  Further, the standby magnet 15, the output magnet 16, and the standby magnet 17 are desirably arranged at equal intervals, so that the rotation determination process by the rotation determination circuit 31 can be performed easily or with high accuracy. It becomes possible. However, the standby magnet 15, the output magnet 16, and the standby magnet 17 do not have to be arranged at equal intervals. The interval Da between the standby magnet 15, the output magnet 16 and the standby magnet 17 is preferably determined in consideration of the hysteresis of the magnetic characteristics of the magnetic elements 21 of the magnetic sensors 1, 2 and 3.

(Operation of moving parts, magnets, magnetic sensors)
In the rotation detection device 100 having the above-described configuration, the movable portion 13, the standby magnet 15, the output magnet 16, the standby magnet 17, and the magnetic sensors 1, 2, and 3 operate as follows.

  For example, if the state shown in FIG. 3 is the initial state, in this initial state, the output magnet 16 faces the magnetic sensor 1 and is in a position close to the magnetic sensor 1, so that the magnetic sensor 1 is output. An output magnetic field is applied by the magnet 16, and an output state is obtained.

  In this state, for example, if an external force is applied to a movable part of an industrial robot that is not turned on, and the rotation shaft 150 of the servo motor provided in the industrial robot starts to rotate rightward due to the external force, Along with this, the movable portion 13 of the rotation detection device 100 also starts to rotate in the right direction. Then, when the movable portion 13 rotates about 30 degrees rightward from the initial state, the standby magnet 15 approaches the magnetic sensor 1. As a result, the magnetic sensor 1 is applied with a standby magnetic field by the standby magnet 15 and enters a standby state.

  When the movable part 13 continues to rotate in the right direction and the movable part 13 rotates about 90 degrees rightward from the initial state, the standby magnet 17 approaches the magnetic sensor 2. As a result, the magnetic sensor 2 is applied with a standby magnetic field by the standby magnet 17 and enters a standby state.

  When the movable part 13 continues to rotate in the right direction and the movable part 13 rotates about 120 degrees rightward from the initial state, the output magnet 16 approaches the magnetic sensor 2. As a result, the magnetic sensor 2 is provided with an output magnetic field by the output magnet 16 and enters an output state. At this time, a detection signal is output from the magnetic sensor 2.

  When the movable unit 13 continues to rotate in the right direction and the movable unit 13 rotates about 150 degrees rightward from the initial state, the standby magnet 15 approaches the magnetic sensor 2. As a result, the magnetic sensor 2 is given a standby magnetic field by the standby magnet 15 and returns to the standby state.

  When the movable portion 13 continues to rotate in the right direction and the movable portion 13 rotates to the right by about 210 degrees from the initial state, the standby magnet 17 approaches the magnetic sensor 3. As a result, the magnetic sensor 3 is applied with a standby magnetic field by the standby magnet 17 and enters a standby state.

  When the movable part 13 continues to rotate in the right direction and the movable part 13 rotates about 240 degrees rightward from the initial state, the output magnet 16 approaches the magnetic sensor 3. As a result, the magnetic sensor 3 is provided with an output magnetic field by the output magnet 16 and enters an output state. At this time, a detection signal is output from the magnetic sensor 3.

  When the movable unit 13 continues to rotate in the right direction and the movable unit 13 rotates to the right by about 270 degrees from the initial state, the standby magnet 15 approaches the magnetic sensor 3. As a result, the magnetic sensor 3 is applied with a standby magnetic field by the standby magnet 15 and returns to the standby state.

  When the movable part 13 continues to rotate in the right direction and the movable part 13 rotates about 330 degrees rightward from the initial state, the standby magnet 17 approaches the magnetic sensor 1. As a result, the magnetic sensor 1 is given a standby magnetic field by the standby magnet 17. At this time, since the magnetic sensor 1 is already in the standby state, the standby state is maintained.

  When the movable part 13 continues to rotate in the right direction and the movable part 13 rotates about 360 degrees rightward from the initial state, the output magnet 16 approaches the magnetic sensor 1. As a result, the magnetic sensor 1 is provided with an output magnetic field by the output magnet 16 and enters an output state. At this time, a detection signal is output from the magnetic sensor 1.

  When the movable unit 13 continues to rotate in the right direction and the movable unit 13 rotates to the right from the initial state by about 390 degrees, the standby magnet 15 approaches the magnetic sensor 1. As a result, the magnetic sensor 1 is applied with a standby magnetic field by the standby magnet 15 and returns to the standby state.

  Even when the rotary shaft 150 rotates to the left and the movable portion 13 rotates to the left along with this, the movable portion 13, the standby magnet 15, the output magnet 16, the standby magnet 17, and the magnetic sensors 1, 2, 3 Operates in substantially the same manner as when the rotating shaft 150 rotates in the right direction.

  Here, a point to be noted in such an operation of the rotation detection device 100 is that, for example, the output magnet 16 moves away from the magnetic sensor 1 as the movable portion 13 rotates in the right direction, and the magnetic sensor disposed next to the output magnet 16. The standby magnet 15 approaches the magnetic sensor 1 before approaching 2. Thereby, before the magnetic sensor 2 will be in an output state, the magnetic sensor 1 will necessarily be in a standby state. Similarly, the standby magnet 15 approaches the magnetic sensor 2 before the movable portion 13 continues to rotate in the right direction, and the output magnet 16 moves away from the magnetic sensor 2 and approaches the magnetic sensor 3 disposed adjacent thereto. To do. Thereby, before the magnetic sensor 3 is in the output state, the magnetic sensor 2 is always in the standby state. As a result, two of the three magnetic sensors 1, 2, and 3 are always in a standby state. Similarly, when the movable portion 13 rotates to the left, two of the three magnetic sensors 1, 2, and 3 are always in a standby state.

  Therefore, no matter how the movable part 13 rotates in the right direction or how it rotates in the left direction, two of the three magnetic sensors 1, 2, and 3 always have the output magnet 16 approaching in the future. Since the detection signal can be output from time to time, even if the movable portion 13 performs a repetitive reversal of the rotation direction without making one rotation, the output magnet 16 has three magnetic sensors 1 and 2. As long as it moves between two magnetic sensors adjacent to each other among the three, a detection signal is output from at least one of the magnetic sensors. Therefore, the rotational state of the rotating shaft 150 can be always accurately grasped.

  Therefore, according to the rotation detection device 100, the three magnetic sensors 1, 2, and 3 can accurately detect the rotation number in consideration of the rotation direction of the rotation shaft 150. That is, the number of magnetic sensors can be reduced to three without impairing the accuracy of detection of the rotational speed in consideration of the rotational direction of the rotary shaft 150, and the rotational detector 100 can be reduced in size, weight, and cost. it can.

(Configuration and operation of circuit unit)
FIG. 4 shows the configuration of the circuit unit 25 in the rotation detection device 100. The circuit unit 25 shown in FIG. 4 detects the number of rotations in consideration of the rotation state of the rotating shaft 150, specifically the rotating direction of the rotating shaft 150, based on detection signals output from the magnetic sensors 1, 2, and 3. As described above, the circuit unit is provided on the substrate 23 (see FIG. 1).

  The circuit unit 25 counts the number of rotations of the rotating shaft 150 according to a first algorithm described below. That is, in the first algorithm, in principle, the signal value corresponding to the detection signal output from any one of the magnetic sensors 1, 2, 3 is stored four times continuously from the present to the past. However, when a detection signal is output from any one of the magnetic sensors 1, 2, 3 and the signal value corresponding to the detection signal output this time is the same as the previously stored signal value, The signal value corresponding to the detection signal output this time is not stored (first exception). In addition, when a detection signal is output from any one of the magnetic sensors 1, 2, and 3, the same arrangement as the signal value corresponding to the detection signal output this time and the previously stored signal value is used. Is already stored, the signal value corresponding to the detection signal output this time is not stored (second exception). The signal values for four times stored in this way represent the locus of rotation of the rotating shaft 150. Therefore, every time a detection signal is output from a magnetic sensor serving as a reference among the magnetic sensors 1, 2, and 3, for example, the magnetic sensor 1, the contents of the signal values for the four times are recognized, and from the recognition result, the rotation axis It is determined whether or not 150 has made one rotation and whether the direction in which the rotation shaft 150 has made one rotation is the right direction or the left direction. As a result of the determination, when the rotation shaft 150 makes one rotation in the right direction, the count value indicating the number of rotations of the rotation shaft 150 is increased by 1. When the rotation shaft 150 makes one rotation in the left direction, Decrease the count by one.

  As shown in FIG. 4, the circuit unit 25 that implements such a first algorithm includes a rotation determination circuit 31 and a counting circuit 32.

  The rotation determination circuit 31 is a circuit that performs a process for determining whether or not the rotation shaft 150 has made one rotation, that is, a rotation determination process, and includes a determination processing unit 33 and a detection signal storage unit 34.

  The determination processing unit 33 determines whether or not the rotation shaft 150 has made one rotation based on the detection signals output from the magnetic sensors 1, 2, and 3. It is an arithmetic processing circuit that outputs a rotation determination signal indicating that one rotation has occurred. For example, the coils 22 of the magnetic sensors 1, 2, and 3 are connected to the determination processing unit 33 via, for example, separate input terminals. Thereby, when the determination processing unit 33 receives the detection signal output from each of the magnetic sensors 1, 2, and 3, the detection signal is output from any of the magnetic sensors 1, 2, and 3. You can recognize whether it is a thing. Further, the determination processing unit 33 can control the detection signal storage unit 43 to store, read, and erase signal values corresponding to the detection signals output from the magnetic sensors 1, 2, and 3, respectively. Further, the determination processing unit 33 recognizes the signal value corresponding to the detection signal output from the magnetic sensors 1, 2, and 3 and the signal value read from the detection signal storage unit 34, and the rotating shaft 150 is recognized based on the recognition result. It is determined whether or not the rotation shaft has made one rotation in the right direction and one rotation in the left direction. When the rotation shaft 150 makes one rotation in the right direction and when the rotation shaft 150 makes one rotation in the left direction, A different rotation judgment signal is output.

  The detection signal storage unit 34 is a storage circuit that stores signal values corresponding to the detection signals output from the magnetic sensors 1, 2, and 3. The detection signal storage unit 34 has a storage capacity capable of storing at least four signal values simultaneously.

  The counting circuit 32 is a circuit that counts the number of rotations of the rotary shaft 150, and includes a count processing unit 36 and a count value storage unit 38.

  The count processing unit 36 is a circuit that counts the number of rotations of the rotating shaft 150 based on the rotation determination signal output from the determination processing unit 33 of the rotation determining circuit 31 and outputs a count value indicating the number of rotations of the rotating shaft 150. is there. That is, the count processing unit 36 receives the rotation determination signal from the determination processing unit 33 of the rotation determination circuit 31 and determines from the rotation determination signal whether the rotation shaft 150 has made one rotation in the right direction or one rotation in the left direction. recognize. The count processing unit 36 reads the count value from the count value storage unit 38. Then, the count processing unit 36 increments the read count value by 1 when the rotating shaft 150 rotates once in the right direction, and counts the read count value when the rotating shaft 150 rotates once in the left direction. The count value decreased by one and incremented by one or decreased by one is stored in the count value storage unit. Further, the count processing unit 36 can read the count value from the count value storage unit 38 and output the count value to the outside.

  The count value storage unit 38 is a storage circuit that stores the count value output from the count processing unit 36.

  Here, the count processing unit 36 outputs a count value indicating the number of rotations of the rotary shaft 150 in gray code. The count value storage unit 38 stores the count value output by the gray code from the count processing unit 36, that is, the gray code of the count value. In this way, by storing the count value as a Gray code, the number of bits to be changed when the count value is stored can be reduced, thereby reducing the number of processes related to storage. Therefore, power consumption can be reduced.

  Further, the circuit unit 25 includes a power supply voltage generation circuit 39. The power supply voltage generation circuit 39 is a circuit that generates a power supply voltage from detection signals output from the magnetic sensors 1, 2, and 3, and includes, for example, a rectifier circuit and a smoothing circuit. The rotation determination circuit 31 and the counting circuit 32 operate with the power supply voltage generated by the power supply voltage generation circuit 39.

  5 and 6 show specific operations of the circuit unit 25 according to the first algorithm. For convenience of explanation, the signal value corresponding to the detection signal output from the magnetic sensor 1 is “1”, the signal value corresponding to the detection signal output from the magnetic sensor 2 is “2”, and is output from the magnetic sensor 3. The signal value corresponding to the detected signal is “3”. The signal values for the four times are treated as one bit string of 8 bits when expressed in binary. That is, the 0th bit (LSB) and the 1st bit of the 8-bit bit string are assigned to the current signal value corresponding to the detection signal output this time from any one of the magnetic sensors 1, 2, and 3. The second and third bits are assigned to the previous signal value, the fourth and fifth bits are assigned to the previous signal value, and the sixth and sixth bits are assigned to the previous signal value. Bit and 7th bit (MSB) shall be assigned. Hereinafter, the 8-bit bit string treated as the signal values for the four times is referred to as a “signal value array”.

  In the table shown in FIG. 6, the leftmost first column indicates a step number. The circuit unit 25 executes rotation determination processing and the like each time a detection signal is output from any one of the magnetic sensors 1, 2, and 3. When one detection signal is output from any one of the magnetic sensors 1, 2, and 3, a series of processes executed by the circuit unit 25 according to the detection signal is defined as one step. The second column in FIG. 6 shows signal values corresponding to the detection signal, the third column shows a signal value array before processing by the determination processing unit 33, and the fourth column shows processing contents by the determination processing unit 33. The fifth column shows the signal value array after processing by the determination processing unit 33, the sixth column shows the determination result by the determination processing unit 33, and the rightmost seventh column is the total after processing by the counting processing unit 36. Numerical values are shown.

  Step S1 in FIG. 6 is an initial state. In the initial state, the output magnet 16 is at a position facing the magnetic sensor 1 (see FIG. 5). The detection signal storage unit 34 stores “1000” as an initial value of the signal value array.

  In step S <b> 2, when the movable unit 13 rotates 120 degrees to the right from the initial state as the rotation shaft 150 rotates in the right direction, and the detection signal is output from the magnetic sensor 2, the determination processing unit 33 The signal value array “1000” stored in the detection signal storage unit 34 is read, the read signal value array is shifted to the right by 2 bits, and the signal value “2” ( "10" in binary number) is placed in the first and second bits of the signal value array. As a result, the signal value array becomes “2100” (“10010000” in binary). Subsequently, the determination processing unit 33 stores (overwrites) the signal value array in the detection signal storage unit 34.

  In step S3, when the rotation of the rotation shaft 150 in the right direction is continued and the movable unit 13 is rotated 120 degrees in the right direction from the state in step S2, and the detection signal is output from the magnetic sensor 3, the determination is made. The processing unit 33 reads the signal value array “2100” stored in the detection signal storage unit 34, right-shifts the read signal value array by 2 bits, and outputs a signal corresponding to the detection signal output from the magnetic sensor 3 this time. The value “3” (“11” in binary) is placed in the first and second bits of the signal value array. As a result, the signal value array becomes “3210” (“11100100” in binary). Subsequently, the determination processing unit 33 stores the signal value array in the detection signal storage unit 34.

  In step S4, when the rotation of the rotary shaft 150 continues in the right direction, the movable unit 13 rotates 120 degrees in the right direction from the state of step S3, and the detection signal is output from the magnetic sensor 1. The processing unit 33 reads the signal value array “3210” stored in the detection signal storage unit 34 and, based on the read signal value array, determines whether or not the rotation shaft 150 has made one rotation rightward or leftward. judge. That is, when the detection signal is output from the magnetic sensor 1 serving as a reference among the magnetic sensors 1, 2, and 3, the determination processing unit 33 determines whether or not the rotating shaft 150 has made one rotation in the right or left direction. Perform the process. In this determination processing, when the signal value array is “3210” or “0321”, the determination processing unit 33 determines that the rotation shaft 150 has made one right turn, and the signal value array is “2310” or “0231”. ”, It is determined that the rotation shaft 150 has made one rotation in the left direction. If the signal value array is other than these, it is determined that the rotation shaft 150 has not made one rotation. Since the signal value array is “3210” in step S4 in FIG. 6, the determination processing unit 33 determines that the rotation shaft 150 has made one rotation in the right direction, and outputs a rotation determination signal indicating that. Then, the determination processing unit 33 deletes the read signal value array “3210” and stores the signal value array “1000” in the detection signal storage unit 34. Further, when the rotation determination signal is output from the determination processing unit 33, the count processing unit 36 reads the count value from the count value storage unit 38 in response to this, increases the read count value by 1, and increases the 1 increase. The count value thus stored is stored (overwritten) in the count value storage unit 38.

  In Step S5, when the rotation of the rotating shaft 150 continues in the right direction, the movable portion 13 rotates 120 degrees in the right direction from the state of Step S4, and thereby the detection signal is output from the magnetic sensor 2. The determination processing unit 33 performs the same process as in step S2. As a result, the signal value array stored in the detection signal storage unit 34 is “2100”.

  In Step S6, when the rotation of the rotating shaft 150 continues in the right direction, the movable portion 13 rotates 120 degrees in the right direction from the state of Step S5, and thereby the detection signal is output from the magnetic sensor 3. The determination processing unit 33 performs the same process as in step S3. As a result, the signal value array stored in the detection signal storage unit 34 is “3210”.

  In step S7, the rotation direction of the rotating shaft 150 is reversed from the right direction to the left direction, and accordingly, the movable portion 13 is rotated 120 degrees in the left direction from the state of step S6. When output, the determination processing unit 33 reads the signal value array “3210” stored in the detection signal storage unit 34, right-shifts the read signal value array by 2 bits, and is output from the magnetic sensor 2 this time. The signal value “2” corresponding to the detection signal is input to the first bit and the second bit of the signal value array. As a result, the signal value array becomes “2321”. Subsequently, the determination processing unit 33 stores the signal value array in the detection signal storage unit 34.

  In step S8, the rotation direction of the rotary shaft 150 returns from the left direction to the right direction, and accordingly, the movable portion 13 rotates 120 degrees in the right direction from the state of step S7, thereby outputting a detection signal from the magnetic sensor 3. Then, the determination processing unit 33 reads the signal value array “2321” stored in the detection signal storage unit 34. Subsequently, the determination processing unit 33 puts “0” in the first bit and the second bit of the signal value array. As a result, the signal value array becomes “0231”. Subsequently, the determination processing unit 33 stores the signal value array in the detection signal storage unit 34. This process is a process for realizing the second exception of the first algorithm. That is, according to the first algorithm, when a detection signal is output from any one of the magnetic sensors 1, 2, and 3, the signal value corresponding to the detection signal output this time and the previously stored signal If the same array as the array composed of the values is already stored, the signal value corresponding to the detection signal output this time is not stored (second exception). In step S8, the signal value corresponding to the detection signal output from the magnetic sensor 3 is “3”, the previously stored signal value is “2”, and the array constituted by both is “32”. The signal value array read from the detection signal storage unit 34 by the determination processing unit 33 in step S8 is “2321”, which includes “32”. Therefore, in step S <b> 8, the determination processing unit 33 does not store the signal value “3” corresponding to the detection signal output from the magnetic sensor 3.

  In step S9, the rotation direction of the rotating shaft 150 is reversed again from the right direction to the left direction, and accordingly, the movable portion 13 rotates 120 degrees in the left direction from the state in step S8, thereby detecting the detection signal from the magnetic sensor 2. Is output, the determination processing unit 33 reads the signal value array “0321” stored in the detection signal storage unit 34 and outputs a signal value “2” corresponding to the detection signal output from the magnetic sensor 2 this time. Place in the first and second bits of the value array. As a result, the signal value array becomes “2321”. Subsequently, the determination processing unit 33 stores the signal value array in the detection signal storage unit 34. In this way, when the first bit and the second bit of the signal value array read from the detection signal storage unit 34 are “0”, the determination processing unit 33 does not perform the process of shifting the signal value array to the right.

  In step S10, the rotation of the rotation shaft 150 in the left direction continues, and accordingly, the movable portion 13 rotates 120 degrees in the left direction from the state in step S9, whereby the detection signal is output from the magnetic sensor 1. The determination processing unit 33 reads the signal value array “2321” stored in the detection signal storage unit 34 and, based on the read signal value array, whether or not the rotation shaft 150 has made one rotation rightward or leftward. Determine whether. Since the signal value array is “2321” in step S <b> 10, the determination processing unit 33 determines that the rotating shaft 150 does not make one rotation. In this case, the determination processing unit 33 does not output a rotation determination signal. Therefore, the count processing unit 36 does not operate. Then, the determination processing unit 33 deletes the read signal value array “2321” and stores the signal value array “1000” in the detection signal storage unit 34.

  Further, the rotation shaft 150 rotates about 30 to 110 degrees in the right direction and 30 to 110 degrees in the left direction from the state of Step S10 (a state where the output magnet 16 is in a position facing the magnetic sensor 1). When the rotation of the degree is repeated, the output magnet 16 continuously approaches and separates from the magnetic sensor 1, so that the detection signal is continuously received from the magnetic sensor 1 as shown in steps S11 and S12. Is output. In this case, the determination processing unit 33 reads the signal value array “1000” stored in the detection signal storage unit 34 every time a detection signal is output from the magnetic sensor 1 in order to recognize this state. Neither the process of shifting the value array to the right nor the process of entering a new value into the signal value array nor the process of storing the signal value array in the detection signal storage unit 34 is performed.

  Further, the determination processing unit 33 performs the processing from step S13 onward in accordance with the rightward or leftward rotation of the movable unit 13 accompanying the rightward or leftward rotation of the rotation shaft 150.

  As described above, according to the circuit unit 25 in the first embodiment of the present invention, the rotation determination circuit 31 and the counting circuit 32 are separated, and the rotation determination signal output from the rotation determination circuit 31 is used as the counting circuit 32. By counting the number of rotations of the rotating shaft 150 based on the above, when the rotation determining signal is output from the rotation determining circuit 32, that is, when the rotating shaft 150 makes one rotation, It can be limited to. Thereby, the period during which the counting circuit 32 operates can be reduced, and power consumption can be reduced.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. 7 to 9, the same components as those of the first embodiment of the present invention shown in FIGS. 1 to 6 are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 7 shows a circuit unit provided in the rotation detection device according to the second embodiment of the present invention. In FIG. 7, the circuit unit 41 is a circuit unit that detects the number of rotations in consideration of the direction of rotation of the rotating shaft 150 based on detection signals output from the magnetic sensors 1, 2, and 3, similarly to the circuit unit 25. Instead of the circuit unit 25, it can be provided on the substrate 23.

  The circuit unit 41 counts the number of rotations of the rotating shaft 150 according to a second algorithm described below. That is, the signal value corresponding to the detection signal output last time from any one of the magnetic sensors 1, 2, 3 is referred to as “previous signal value”, and is output from any one of the magnetic sensors 1, 2, 3 this time. Assuming that the signal value corresponding to the detected signal is “current signal value”, the second algorithm compares the previous signal value with the current signal value, and thereby the rotation amount considering the rotation direction of the rotating shaft 150. (The amount of movement of the rotating shaft 150 in the right rotation direction or the left rotation direction that is less than one rotation) is recognized. Then, from the cumulative value of the rotation amount, it is determined whether or not the rotation shaft 150 has made one rotation and whether the direction in which the rotation shaft 150 has made one rotation is the right direction or the left direction. As a result of the determination, when the rotation shaft 150 makes one rotation in the right direction, the count value indicating the number of rotations of the rotation shaft 150 is increased by 1. When the rotation shaft 150 makes one rotation in the left direction, Decrease the count by one. Information that needs to be stored in order to realize the second algorithm is a signal value for one time (previous signal value) and the amount of rotation of the rotary shaft 150.

  As shown in FIG. 7, the rotation determination circuit 42 of the circuit unit 41 that implements such a second algorithm includes a determination processing unit 43, a detection signal storage unit 44, and a rotation amount storage unit 45.

  The determination processing unit 43 is an arithmetic processing circuit that performs rotation determination processing according to the second algorithm described above, and is output from the magnetic sensors 1, 2, and 3 in substantially the same manner as the determination processing unit 33 in the first embodiment. A detection signal is received, and it is recognized which of the magnetic sensors 1, 2, and 3 the received detection signal is output from. Further, the determination processing unit 43 recognizes the rotation direction and the rotation amount of the rotation shaft 150 by comparing the previous signal value and the current signal value. Further, the determination processing unit 43 controls the detection signal storage unit 44 to store, read, and erase the signal value, and controls the rotation amount storage unit 45 to store, read, and delete the rotation amount. Further, the determination processing unit 43 recognizes each of the current signal value, the previous signal value, and the rotation amount read from the rotation amount storage unit 45, and whether or not the rotation shaft 150 has made one right rotation based on the recognition result, It is determined whether or not it has made one rotation in the left direction, and different rotation determination signals are output when the rotation shaft 150 makes one rotation in the right direction and when the rotation shaft 150 makes one rotation in the left direction.

  The detection signal storage unit 44 is a storage circuit that stores signal values corresponding to the detection signals output from the magnetic sensors 1, 2, and 3. The detection signal storage unit 44 has a storage capacity capable of storing at least one signal value.

  The rotation amount storage unit 45 is a storage circuit that stores the rotation amount of the rotation shaft 150 recognized by the determination processing unit 43. The rotation amount storage unit 45 has a storage capacity capable of storing at least one rotation amount.

  8 and 9 show a specific operation of the circuit unit 41 according to the second algorithm. For convenience of explanation, similarly to the first embodiment described above, the signal values corresponding to the detection signals output from the magnetic sensors 1, 2, and 3 are “1”, “2”, and “3”, respectively.

  In the table shown in FIG. 9, the leftmost first column indicates step numbers as in FIG. Further, the second column in FIG. 9 indicates the signal value corresponding to the detection signal, the third column indicates the signal value before processing by the determination processing unit 43, and the fourth column indicates the signal value by the determination processing unit 43. The processing content is shown, and the fifth column shows the signal value after processing by the determination processing unit 43. Further, the sixth column in FIG. 9 indicates the rotation amount before the processing by the determination processing unit 43, the seventh column indicates the processing content regarding the rotation amount by the determination processing unit 43, and the eighth column by the determination processing unit 43. The rotation amount after processing is shown. Further, the ninth column in FIG. 9 indicates the determination result by the determination processing unit 43, and the rightmost tenth column indicates the count value after processing by the count processing unit 36.

  Step S21 in FIG. 9 is an initial state. In the initial state, the output magnet 16 is at a position facing the magnetic sensor 1 (see FIG. 8). The detection signal storage unit 44 stores “1” as the initial value of the previous signal value, and the rotation amount storage unit 45 stores “0” as the initial value of the rotation amount.

  In step S22, when the movable unit 13 rotates 120 degrees from the initial state to the right as the rotation shaft 150 rotates in the right direction, and the detection signal is output from the magnetic sensor 2, the determination processing unit 43 The previous signal value “1” stored in the detection signal storage unit 44 is read, and the previous signal value “1” is compared with the current signal value “2” corresponding to the detection signal output from the magnetic sensor 2 this time. The amount of rotation of the rotating shaft 150 is recognized. Here, the determination processing unit 43 compares the previous signal value and the current signal value, and when the previous signal value and the current signal value are “1” and “2”, respectively, “2” and “3”. If it is “3” or “1”, it is recognized that the rotary shaft 150 has rotated 120 degrees rightward, while the previous signal value and the current signal value are “1”, “3”. If it is “3”, “2”, or “2”, “1”, it is recognized that the rotary shaft 150 has rotated 120 degrees to the left. In step S22, since the previous signal value and the current signal value are “1” and “2”, respectively, the determination processing unit 43 recognizes that the rotation shaft 150 has rotated 120 degrees in the right direction. Subsequently, in step S <b> 22, the determination processing unit 43 stores (overwrites) the current signal value “2” in the detection signal storage unit 44. Further, the determination processing unit 43 reads the rotation amount “0” stored in the rotation amount storage unit 45, increases the read rotation amount “0” by 1, and increases the increased rotation amount “1” to the rotation amount. Store (overwrite) in the storage unit 45.

  In step S23, when the rotation of the rotating shaft 150 continues in the right direction, the movable unit 13 rotates 120 degrees in the right direction from the state of step S22, and thus the detection signal is output from the magnetic sensor 3. The determination processing unit 43 reads the previous signal value “2” stored in the detection signal storage unit 44, and the current signal value corresponding to the previous signal value “2” and the detection signal output from the magnetic sensor 3 this time. Compared with “3”, it is recognized that the rotary shaft 150 has rotated 120 degrees to the right. Subsequently, in step S <b> 23, the determination processing unit 43 stores the current signal value “3” in the detection signal storage unit 44. Further, the determination processing unit 43 reads the rotation amount “1” stored in the rotation amount storage unit 45, increases the read rotation amount “1” by 1, and sets the increased rotation amount “2” as the rotation amount. Store in the storage unit 45.

  In step S24, the rotation of the rotary shaft 150 in the right direction continues, and accordingly, the movable part 13 rotates 120 degrees in the right direction from the state in step S23, and thereby the detection signal is output from the magnetic sensor 1. The determination processing unit 43 reads the previous signal value “3” stored in the detection signal storage unit 44, and the current signal value corresponding to the previous signal value “3” and the detection signal output from the magnetic sensor 1 this time. Compared with “1”, it is recognized that the rotary shaft 150 has rotated 120 degrees to the right. Subsequently, in step S <b> 24, the determination processing unit 43 stores the current signal value “1” in the detection signal storage unit 44. Further, the determination processing unit 43 reads the rotation amount “2” stored in the rotation amount storage unit 45 and increments the read rotation amount “2” by one. As a result, the rotation amount is “3”.

  Here, in the step in which the detection signal is output from the magnetic sensor 1, the determination processing unit 43 determines whether or not the rotating shaft 150 has made one rotation. That is, the determination processing unit 43 determines that the rotation shaft 150 has made one rotation in the right direction when the rotation amount after incrementing by 1 in the step in which the detection signal is output from the magnetic sensor 1 becomes “3”. A rotation determination signal indicating that the rotation shaft 150 has made one rotation in the right direction is output. Further, the determination processing unit 43 determines that the rotation shaft 150 has made one rotation in the left direction when the rotation amount after being decreased by 1 in the step in which the detection signal is output from the magnetic sensor 1 becomes “−3”. The rotation determination signal indicating that the rotation shaft 150 has made one rotation in the left direction is output. In addition, in the step in which the detection signal is output from the magnetic sensor 1, the determination processing unit 43 determines that the rotation amount after being increased by 1 does not become “3”, or the rotation amount after being reduced by 1 is “−3”. If not, it is determined that the rotating shaft 150 has not made one rotation, and no rotation determination signal is output. Since the rotation amount after incrementing by 1 in step S24 in which the detection signal is output from the magnetic sensor 1 is “3”, the determination processing unit 43 determines that the rotation shaft 150 has made one rotation in the right direction, and the rotation shaft 150 has A rotation determination signal indicating that one rotation has been made in the right direction is output. Then, the determination processing unit 43 deletes the rotation amount. That is, the determination processing unit 43 stores the rotation amount “0” in the rotation amount storage unit 45. When the rotation determination signal is output from the determination processing unit 43, the count processing unit 36 reads the count value from the count value storage unit 38 in response to this, increases the read count value by 1, and increases the increment by 1. The count value thus stored is stored (overwritten) in the count value storage unit 38.

  In step S25, when the rotation of the rotation shaft 150 continues in the right direction, the movable portion 13 rotates 120 degrees in the right direction from the state in step S24, and thereby the detection signal is output from the magnetic sensor 2. The determination processing unit 43 performs the same process as in step S22. As a result, the signal value stored in the detection signal storage unit 44 is “2”, and the rotation amount stored in the rotation amount storage unit 45 is “1”.

  In step S26, when the rotation of the rotating shaft 150 continues in the right direction, the movable portion 13 rotates 120 degrees in the right direction from the state of step S25, and thereby the detection signal is output from the magnetic sensor 3. The determination processing unit 43 performs the same process as in step S23. As a result, the signal value stored in the detection signal storage unit 44 is “3”, and the rotation amount stored in the rotation amount storage unit 45 is “2”.

  In step S27, the rotation direction of the rotating shaft 150 changes from the right direction to the left direction, and accordingly, the movable part 13 rotates 120 degrees in the left direction from the state of step S26, whereby the detection signal is output from the magnetic sensor 2. When output, the determination processing unit 43 reads the previous signal value “3” stored in the detection signal storage unit 44 and corresponds to the previous signal value “3” and the detection signal output from the magnetic sensor 2 this time. The current signal value “2” is compared, and it is recognized that the rotating shaft 150 has rotated 120 degrees to the left. Subsequently, in step S <b> 27, the determination processing unit 43 stores the current signal value “2” in the detection signal storage unit 44. Further, the determination processing unit 43 reads the rotation amount “2” stored in the rotation amount storage unit 45, decreases the read rotation amount “2” by 1, and sets the reduced rotation amount “1” as the rotation amount. Store in the storage unit 45.

  In step S28, the rotation direction of the rotating shaft 150 returns from the left direction to the right direction, and accordingly, the movable portion 13 rotates 120 degrees in the right direction from the state of step S27, thereby outputting a detection signal from the magnetic sensor 3. When the determination is made, the determination processing unit 43 performs the same process as in step S23. As a result, the signal value stored in the detection signal storage unit 44 is “3”, and the rotation amount stored in the rotation amount storage unit 45 is “2”.

  In step S29, the rotation direction of the rotary shaft 150 changes again from the right direction to the left direction, and accordingly, the movable portion 13 rotates 120 degrees in the left direction from the state of step S28, thereby detecting the detection signal from the magnetic sensor 2. Is output, the determination processing unit 43 performs the same process as in step S27. As a result, the signal value stored in the detection signal storage unit 44 is “2”, and the rotation amount stored in the rotation amount storage unit 45 is “1”.

  In Step S30, when the rotation of the rotation shaft 150 continues in the left direction, the movable portion 13 rotates 120 degrees in the left direction from the state in Step S29, and thereby the detection signal is output from the magnetic sensor 1. The determination processing unit 43 reads the previous signal value “2” stored in the detection signal storage unit 44, and the current signal value corresponding to the previous signal value “2” and the detection signal output from the magnetic sensor 2 this time. Compared with “1”, it is recognized that the rotating shaft 150 has rotated 120 degrees to the left. Subsequently, in step S <b> 30, the determination processing unit 43 stores the current signal value “1” in the detection signal storage unit 44. Further, the determination processing unit 43 reads the rotation amount “1” stored in the rotation amount storage unit 45 and decreases the read rotation amount “1” by one. As a result, the rotation amount becomes “0”. Then, the determination processing unit 43 deletes the rotation amount stored in the rotation amount storage unit 45. As a result, the rotation amount stored in the rotation amount storage unit 45 is “0”. Further, as described above, the determination processing unit 43 determines whether or not the rotation shaft 150 has made one rotation at the step in which the detection signal is output from the magnetic sensor 1. Since the rotation amount after decreasing by 1 in step S30 when the detection signal is output from the magnetic sensor 1 is “0”, the determination processing unit 43 determines that the rotating shaft 150 does not make one rotation and outputs a rotation determination signal. do not do.

  Further, the rotation shaft 150 rotates about 30 degrees to 110 degrees in the right direction and 30 degrees to 110 degrees in the left direction from the state of step S30 (the state where the output magnet 16 is located opposite to the magnetic sensor 1), for example. When the rotation of about 20 degrees is repeated, the output magnet 16 continuously approaches and separates from the magnetic sensor 1, so that the detection signal from the magnetic sensor 1 is continuous as shown in steps S31 and S32. Is output. In this case, every time a detection signal is output from the magnetic sensor 1, the determination processing unit 43 reads the previous signal value “1” stored in the detection signal storage unit 44, and uses the previous signal value “1” as the magnetic signal. The current signal value “1” corresponding to the detection signal output from the sensor 1 this time is compared. And the determination process part 43 recognizes from the said comparison result that the rotation amount of the rotating shaft 150 has not reached 120 degree | times. In this case, the determination processing unit 43 performs processing for storing the current signal value in the detection signal storage unit 44, processing for reading the rotation amount from the rotation amount storage unit 45, processing for increasing or decreasing the rotation amount, Is also not stored in the rotation amount storage unit 45.

  Furthermore, according to the rightward or leftward rotation of the movable unit 13 accompanying the rotation of the rotation shaft 150 in the rightward or leftward direction, the determination processing unit 43 performs processing subsequent to step S33.

  As described above, according to the circuit unit 41 according to the second embodiment, the rotation determination circuit 42 and the counting circuit 32 are separated and rotated from the rotation determination circuit 42 as in the circuit unit 25 according to the first embodiment. The power consumption can be reduced by operating the counting circuit 32 only when the determination signal is output. Furthermore, according to the circuit unit 41 according to the second embodiment, the storage capacity that is the sum of the storage capacity of the detection signal storage unit 44 and the storage capacity of the rotation amount storage unit 45 in the circuit unit 25 according to the first embodiment. The storage capacity of the detection signal storage unit 34 can be made smaller. That is, the detection signal storage unit 34 in the circuit unit 25 according to the first embodiment needs a storage capacity capable of storing signal values for at least four times, for example, a storage capacity of 8 bits. On the other hand, in the circuit unit 41 according to the second embodiment, the detection signal storage unit 44 suffices with a storage capacity capable of storing at least one signal value, for example, a 2-bit storage capacity, and a rotation amount storage unit. 45 is a storage capacity capable of storing at least one rotation amount, for example, a 3-bit storage capacity, and a combined storage capacity of 5 bits is sufficient. In this respect as well, power consumption can be reduced.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. 10 to 12, the same components as those of the first embodiment of the present invention shown in FIGS. 1 to 6 are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 10 shows a circuit unit provided in the rotation detection device according to the third embodiment of the present invention. In FIG. 10, a circuit unit 51 is a circuit unit that detects the number of rotations in consideration of the direction of rotation of the rotating shaft 150 based on detection signals output from the magnetic sensors 1, 2, and 3, similarly to the circuit unit 25. Instead of the circuit unit 25, it can be provided on the substrate 23.

  The circuit unit 51 counts the number of rotations of the rotating shaft 150 according to a third algorithm described below. In the third algorithm, similarly to the second algorithm in the second embodiment described above, the rotation amount in consideration of the rotation direction of the rotating shaft 150 is recognized by comparing the previous signal value and the current signal value. . Then, based on this rotation amount, it is determined whether or not the rotation shaft 150 has made one rotation and whether the direction in which the rotation shaft 150 has made one rotation is the right direction or the left direction. As a result of the determination, when the rotation shaft 150 makes one rotation in the right direction, the count value indicating the number of rotations of the rotation shaft 150 is increased by 1. When the rotation shaft 150 makes one rotation in the left direction, Decrease the count by one.

  The third algorithm is different from the second algorithm in the method of storing the rotation amount of the rotating shaft 150. That is, when the rotary shaft 150 rotates once in the right direction from the state where the output magnet 16 is at the position facing the magnetic sensor 1, the detection signal is first output from the magnetic sensor 2, and then the detection signal is output from the magnetic sensor 3. Then, a detection signal is output from the magnetic sensor 1. In the second algorithm described above, each time a detection signal is output from the magnetic sensors 2, 3, 1, A process of reading the rotation amount from the rotation amount storage unit 45, a process of increasing the rotation amount by 1, and a process of storing the rotation amount increased by 1 in the rotation amount storage unit 45 are performed. Further, when a detection signal is output from the magnetic sensor 1, a process for determining whether or not the rotating shaft 150 has made one rotation from the amount of rotation after incrementing by one is performed. Further, when the rotary shaft 150 makes one rotation leftward from the state in which the output magnet 16 is opposed to the magnetic sensor 1, the detection signal is first output from the magnetic sensor 3, and then the detection signal is output from the magnetic sensor 2. Then, a detection signal is output from the magnetic sensor 1. In the second algorithm described above, each time a detection signal is output from the magnetic sensors 3, 2, 1, A process of reading the rotation amount from the rotation amount storage unit 45, a process of reducing the rotation amount by 1, and a process of storing the rotation amount reduced by 1 in the rotation amount storage unit 45 are performed. Further, when a detection signal is output from the magnetic sensor 1, processing for determining whether or not the rotating shaft 150 has made one rotation is performed based on the amount of rotation after being decreased by one.

  On the other hand, in the third algorithm, when the rotary shaft 150 makes one right turn from the state where the output magnet 16 is opposed to the magnetic sensor 1, a detection signal is first output from the magnetic sensor 2. In some cases, only the process of storing the rotation amount substitution value “m” in the rotation amount substitution value storage unit 55 described later is performed. Next, when a detection signal is output from the magnetic sensor 3, processing for reading the rotation amount substitution value “m” from the rotation amount substitution value storage unit 55, processing for increasing the rotation amount substitution value “m” by 1, and incrementing by 1 The stored rotation amount substitution value “m + 1” is stored in the rotation amount substitution value storage unit 55. Next, when a detection signal is output from the magnetic sensor 1, a process for reading the rotation amount substitute value “m + 1” from the rotation amount substitute value storage unit 55, and whether the rotation shaft 150 has made one rotation from the rotation amount substitute value “m + 1”. Processing to determine whether or not. Further, when the rotation shaft 150 makes one rotation in the left direction from the state where the output magnet 16 is at the position facing the magnetic sensor 1, when the detection signal is first output from the magnetic sensor 3, the rotation amount substitution value “n”. Is stored in the rotation amount substitute value storage unit 55 only. Next, when a detection signal is output from the magnetic sensor 2, a process of reading the rotation amount substitute value “n” from the rotation amount substitute value storage unit 55, a process of decreasing the rotation amount substitute value “n” by 1, and a decrease of 1 The stored rotation amount substitution value “n−1” is stored in the rotation amount substitution value storage unit 55. Next, when a detection signal is output from the magnetic sensor 1, the rotation amount substitution value “n−1” is read from the rotation amount substitution value storage unit 55, and the rotation shaft 150 starts from the rotation amount substitution value “n−1”. A process for determining whether or not one rotation has been performed is performed.

  Further, in the third algorithm, both of the rotation amount substitution values “m” and “m + 1” during which the rotation shaft 150 makes one rotation in the right direction, while the rotation shaft 150 makes one rotation in the left direction. The rotation amount substitution values “n” and “n−1” are different from each other. As long as this condition is satisfied, the rotation amount substitute value may be any numerical value. However, in order to reduce the storage capacity of the rotation amount substitution value storage unit 55, it is desirable that the rotation amount substitution value is a small numerical value. The information that needs to be stored in order to realize the third algorithm is a signal value (previous signal value) for one time and a rotation amount substitute value.

  According to the third algorithm, the number of processes related to rotation determination can be reduced as compared with the second algorithm. That is, processing for reading the rotation amount substitute value performed in the third algorithm from the rotation amount substitution value storage unit 55, processing for increasing the rotation amount substitution value by 1 or 1 and rotation amount substitution value increased by 1 or 1 Is stored in the rotation amount substitution value storage unit 55. The total number of processes stored in the rotation amount substitution value storage unit 55 is a process of reading the rotation amount performed in the second algorithm from the rotation amount storage unit 45, a process of increasing or decreasing the rotation amount by 1, and The rotation amount reduced by 1 is smaller than the total number of processes stored in the rotation amount storage unit 45. Therefore, power consumption can be further reduced.

  The rotation determination circuit 52 of the circuit unit 51 that implements such a third algorithm includes a determination processing unit 53, a detection signal storage unit 54, and a rotation amount alternative value storage unit 55, as shown in FIG.

  The determination processing unit 53 is an arithmetic processing circuit that performs rotation determination processing according to the above-described third algorithm. Although there are some differences such as handling the rotation amount substitute value, the determination processing unit 43 in the second embodiment is used. And substantially the same configuration.

  The detection signal storage unit 54 is a storage circuit that stores signal values corresponding to the detection signals output from the magnetic sensors 1, 2, and 3. The detection signal storage unit 54 has a storage capacity capable of storing at least one signal value.

  The rotation amount substitution value storage unit 55 is a storage circuit that stores a rotation amount substitution value. The rotation amount substitute value storage unit 55 has a storage capacity capable of storing at least one rotation amount substitute value.

  11 and 12 show a specific operation of the circuit unit 51 according to the third algorithm. For convenience of explanation, similarly to the first embodiment described above, the signal values corresponding to the detection signals output from the magnetic sensors 1, 2, and 3 are “1”, “2”, and “3”, respectively.

  In the table shown in FIG. 12, the leftmost first column indicates step numbers as in FIG. The second column in FIG. 12 indicates the signal value corresponding to the detection signal, the third column indicates the signal value before processing by the determination processing unit 53, and the fourth column indicates the signal value by the determination processing unit 53. The processing content is shown, and the fifth column shows a signal value after processing by the determination processing unit 53. Further, the sixth column in FIG. 12 shows the rotation amount substitute value before the processing by the determination processing unit 53, the seventh column shows the processing content of the rotation amount substitute value by the determination processing unit 53, and the eighth column is the determination. The rotation amount alternative value after processing by the processing unit 53 is shown. Further, the ninth column in FIG. 12 indicates the determination result by the determination processing unit 53, and the rightmost tenth column indicates the count value after processing by the count processing unit 36.

  Step S41 in FIG. 12 is an initial state. In the initial state, the output magnet 16 is at a position facing the magnetic sensor 1 (see FIG. 11). The detection signal storage unit 54 stores “1” as the initial value of the previous signal value, and the rotation amount substitute value storage unit 55 stores “0” as the initial value.

  In step S42, when the movable unit 13 rotates 120 degrees rightward from the initial state as the rotation shaft 150 rotates in the right direction, and the detection signal is output from the magnetic sensor 2, the determination processing unit 53 The previous signal value “1” stored in the detection signal storage unit 54 is read, and the previous signal value “1” is compared with the current signal value “2” corresponding to the detection signal output from the magnetic sensor 2 this time. The amount of rotation of the rotating shaft 150 is recognized. Here, the determination processing unit 53 compares the previous signal value with the current signal value, and when the previous signal value and the current signal value are “1” and “2”, respectively, “2” and “3”. If it is “3” or “1”, it is recognized that the rotary shaft 150 has rotated 120 degrees rightward, while the previous signal value and the current signal value are “1”, “3”. If it is “3”, “2”, or “2”, “1”, it is recognized that the rotary shaft 150 has rotated 120 degrees to the left. In step S42, since the previous signal value and the current signal value are “1” and “2”, respectively, the determination processing unit 53 recognizes that the rotation shaft 150 has rotated 120 degrees in the right direction. Subsequently, in step S <b> 42, the determination processing unit 53 stores (overwrites) the current signal value “2” in the detection signal storage unit 54. Further, the determination processing unit 53 stores (overwrites) “2” in the rotation amount substitute value storage unit 55 as the rotation amount substitute value.

  In Step S43, when the rotation of the rotation shaft 150 continues in the right direction, the movable portion 13 rotates 120 degrees in the right direction from the state of Step S42, and thereby the detection signal is output from the magnetic sensor 3. The determination processing unit 53 reads the previous signal value “2” stored in the detection signal storage unit 54, the previous signal value “2”, and the current signal value corresponding to the detection signal output from the magnetic sensor 2 this time. Compared with “3”, it is recognized that the rotary shaft 150 has rotated 120 degrees to the right. Subsequently, in step S <b> 43, the determination processing unit 53 stores the current signal value “3” in the detection signal storage unit 54. Further, the determination processing unit 53 reads the rotation amount substitution value “2” stored in the rotation amount substitution value storage unit 55, increases the read rotation amount substitution value “2” by 1, and increases the rotation amount. The substitution value “3” is stored in the rotation amount substitution value storage unit 55.

  In step S44, when the rotation of the rotation shaft 150 continues in the right direction, the movable portion 13 rotates 120 degrees in the right direction from the state in step S43, and thereby the detection signal is output from the magnetic sensor 1. The determination processing unit 53 reads the previous signal value “3” stored in the detection signal storage unit 54, and the previous signal value “3” and the current signal value corresponding to the detection signal output from the magnetic sensor 1 this time. Compared with “1”, it is recognized that the rotary shaft 150 has rotated 120 degrees to the right. Subsequently, in step S <b> 44, the determination processing unit 53 stores the current signal value “1” in the detection signal storage unit 54. Further, the determination processing unit 53 reads the rotation amount substitution value “3” stored in the rotation amount substitution value storage unit 55. However, the determination processing unit 53 does not perform a process of changing the rotation amount substitute value nor a process of storing the rotation amount substitute value in the rotation amount substitute value storage unit 55 in step S44.

  Here, in the step in which the detection signal is output from the magnetic sensor 1, the determination processing unit 53 determines whether or not the rotating shaft 150 has made one rotation. That is, in the step in which the detection signal is output from the magnetic sensor 1, the determination processing unit 53 determines that the rotation amount alternative value read from the rotation amount alternative value storage unit 55 is “ When “3”, it is determined that the rotation shaft 150 has made one rotation in the right direction, and a rotation determination signal indicating that the rotation shaft 150 has made one rotation in the right direction is output. In addition, in the step in which the detection signal is output from the magnetic sensor 1, the determination processing unit 53 indicates that the rotation direction of the rotation shaft 150 is the left direction, and the rotation amount substitution value read from the rotation amount substitution value storage unit 55 is “0”. ”, It is determined that the rotation shaft 150 has made one rotation in the left direction, and a rotation determination signal indicating that the rotation shaft 150 has made one rotation in the left direction is output. In step S44 in which the detection signal is output from the magnetic sensor 1, the rotation direction of the rotary shaft 150 is the right direction, and the rotation amount alternative value read from the rotation amount replacement value storage unit 55 is “3”. The unit 53 determines that the rotation shaft 150 has made one rotation in the right direction, and outputs a rotation determination signal indicating that the rotation shaft 150 has made one rotation in the right direction. When the rotation determination signal is output from the determination processing unit 53, the count processing unit 36 reads the count value from the count value storage unit 38 in response to this, increases the read count value by 1, and increases the count by 1. The count value is stored (overwritten) in the count value storage unit 38.

  In step S45, when the rotation of the rotary shaft 150 continues in the right direction, the movable portion 13 rotates 120 degrees in the right direction from the state in step S44, and thereby the detection signal is output from the magnetic sensor 2. The determination processing unit 53 performs the same process as in step S42. As a result, the signal value stored in the detection signal storage unit 54 is “2”, and the rotation amount substitution value stored in the rotation amount substitution value storage unit 55 is “2”.

  In step S46, when the rotation of the rotary shaft 150 continues in the right direction, the movable unit 13 rotates 120 degrees in the right direction from the state of step S45, and thereby the detection signal is output from the magnetic sensor 3. The determination processing unit 53 performs the same process as in step S43. As a result, the signal value stored in the detection signal storage unit 54 is “3”, and the rotation amount stored in the rotation amount substitute value storage unit 55 is “3”.

  In step S47, the rotation direction of the rotating shaft 150 changes from the right direction to the left direction, and accordingly, the movable portion 13 rotates 120 degrees to the left from the state in step S46, whereby a detection signal is output from the magnetic sensor 2. When output, the determination processing unit 53 reads the previous signal value “3” stored in the detection signal storage unit 54 and corresponds to the previous signal value “3” and the detection signal output from the magnetic sensor 2 this time. The current signal value “2” is compared, and it is recognized that the rotating shaft 150 has rotated 120 degrees to the left. Subsequently, in step S <b> 47, the determination processing unit 53 stores the current signal value “2” in the detection signal storage unit 54. Further, the determination processing unit 53 reads the rotation amount substitution value “3” stored in the rotation amount substitution value storage unit 55, decreases the read rotation amount substitution value “3” by 1, and reduces the reduced rotation amount. The substitute value “2” is stored in the rotation amount substitute value storage unit 55.

  In step S48, the rotation direction of the rotary shaft 150 returns from the left direction to the right direction, and accordingly, the movable part 13 rotates 120 degrees to the right from the state in step S47, thereby outputting a detection signal from the magnetic sensor 3. When the determination is made, the determination processing unit 53 performs the same processing as in step S43. As a result, the signal value stored in the detection signal storage unit 54 is “3”, and the rotation amount substitution value stored in the rotation amount substitution value storage unit 55 is “3”.

  In step S49, the rotation direction of the rotating shaft 150 changes again from the right direction to the left direction, and accordingly, the movable portion 13 rotates 120 degrees in the left direction from the state in step S48, thereby detecting the detection signal from the magnetic sensor 2. Is output, the determination processing unit 53 performs the same processing as in step S47. As a result, the signal value stored in the detection signal storage unit 54 is “2”, and the rotation amount stored in the rotation amount substitute value storage unit 55 is “2”.

  In step S50, the rotation of the rotation shaft 150 in the left direction is continued, and accordingly, the movable portion 13 is rotated 120 degrees in the left direction from the state in step S49, whereby the detection signal is output from the magnetic sensor 1. The determination processing unit 53 reads the previous signal value “2” stored in the detection signal storage unit 54, and the current signal value corresponding to the previous signal value “2” and the detection signal output from the magnetic sensor 1 this time. Compared with “1”, it is recognized that the rotating shaft 150 has rotated 120 degrees to the left. Subsequently, in step S <b> 50, the determination processing unit 53 stores the current signal value “1” in the detection signal storage unit 54. Further, the determination processing unit 53 reads the rotation amount substitution value “2” stored in the rotation amount substitution value storage unit 55. However, the determination processing unit 53 does not perform a process of changing the rotation amount substitute value or a process of storing the rotation amount substitute value in the rotation amount substitute value storage unit 55 in step S50. Further, as described above, the determination processing unit 53 determines whether or not the rotation shaft 150 has made one rotation at the step in which the detection signal is output from the magnetic sensor 1. In step S50 in which the detection signal is output from the magnetic sensor 1, the rotation direction of the rotary shaft 150 is the left direction, but the rotation amount alternative value read from the rotation amount alternative value storage unit 55 is “2”. 53 does not output a rotation determination signal.

  Further, for example, the rotation shaft 150 rotates about 30 to 110 degrees in the right direction and 30 degrees to 110 in the left direction from the state of step S50 (the state where the output magnet 16 is in a position facing the magnetic sensor 1). When the rotation of about 20 degrees is repeated, the output magnet 16 continuously approaches and separates from the magnetic sensor 1, so that the detection signal from the magnetic sensor 1 is continuous as shown in steps S51 and S52. Is output. In this case, every time a detection signal is output from the magnetic sensor 1, the determination processing unit 53 reads the previous signal value “1” stored in the detection signal storage unit 54, and the detection signal output this time from the magnetic sensor 1. Is compared with the current signal value “1” corresponding to. And the determination process part 53 recognizes from the said comparison result that the rotation amount of the rotating shaft 150 has not reached 120 degree | times. In this case, the determination processing unit 53 increases or decreases the rotation amount substitution value both in the process of storing the current signal value in the detection signal storage unit 54 and in the process of reading the rotation amount substitution value from the rotation amount substitution value storage unit 55. Neither the processing to store the rotation amount substitution value nor the processing to store the rotation amount substitution value in the rotation amount substitution value storage 55 is performed.

  Furthermore, the determination processing unit 53 performs the processing from step S53 onward in accordance with the rightward or leftward rotation of the movable unit 13 accompanying the rightward or leftward rotation of the rotation shaft 150.

  As described above, according to the third embodiment, in addition to the operational effects obtained by the second embodiment, as described above, by adopting the third algorithm, the number of processes related to rotation determination can be reduced. Therefore, the power consumption can be further reduced as compared with the case where the algorithm 2 is adopted. In the circuit unit 41 according to the second embodiment, the storage capacity (2 bits) of the detection signal storage unit 44 and the storage capacity (3 bits) of the rotation amount storage unit 45 are combined to reduce the storage capacity to 5 bits. However, in the circuit unit 51 according to the third embodiment, the storage capacity (2 bits) of the detection signal storage unit 54 and the storage capacity (2 bits) of the rotation amount alternative value storage unit 55 are combined to increase the storage capacity. It can be reduced to 4 bits. In this respect as well, the reduction of power consumption can be promoted.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIGS. 13 to 15, the same components as those of the first embodiment of the present invention shown in FIGS. 1 to 6 are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 13 shows a circuit unit provided in the rotation detection device according to the fourth embodiment of the present invention. In FIG. 13, a circuit unit 61 is a circuit unit that detects the number of rotations in consideration of the direction of rotation of the rotating shaft 150 based on detection signals output from the magnetic sensors 1, 2, and 3, similarly to the circuit unit 25. Instead of the circuit unit 25, it can be provided on the substrate 23.

  The circuit unit 51 counts the number of rotations of the rotating shaft 150 according to a fourth algorithm described below. The fourth algorithm is based on the following concept. That is, when the rotating shaft 150 rotates once in the right direction from the state where the output magnet 16 is opposed to the magnetic sensor 1, the output magnet 16 is rotated when the movable portion 13 rotates once in the right direction. Immediately after the rotation of the movable part 13 starts, passes through the vicinity of the magnetic sensor 2 arranged on the right in the circumferential direction of the magnetic sensor 1 and immediately before the movable part 13 makes one rotation, the circumferential direction of the magnetic sensor 1 Passes in the vicinity of the magnetic sensor 3 arranged on the left side. Therefore, due to the rotation of the movable portion 13 accompanying the rotation of the rotating shaft 150, the fact that the output magnet 16 has passed near the magnetic sensor 2 immediately after starting to move from the position facing the magnetic sensor 1, and the magnetic sensor 1. By recognizing the fact that the magnetic sensor 3 has passed in the vicinity immediately before returning to the position facing the rotation axis 150, it can be determined that the rotation shaft 150 has made one rotation in the right direction. Further, when the output magnet 16 is in a position facing the magnetic sensor 1 and the rotating shaft 150 makes one rotation leftward, and accordingly the movable portion 13 makes one rotation leftward, the output magnet 16 Passes through the vicinity of the magnetic sensor 3 arranged on the left side in the circumferential direction of the magnetic sensor 1 immediately after the rotation of the movable part 13 and immediately before the movable part 13 makes one rotation, the circumferential direction of the magnetic sensor 1 It passes in the vicinity of the magnetic sensor 2 arranged on the right side. Accordingly, the fact that the output magnet 16 has passed through the vicinity of the magnetic sensor 3 immediately after starting to move from the position facing the magnetic sensor 1 due to the rotation of the movable portion 13 accompanying the rotation of the rotating shaft 150, and the magnetic sensor 1. It is possible to determine that the rotating shaft 150 has made one rotation in the left direction by recognizing the fact that it has passed through the vicinity of the magnetic sensor 2 immediately before returning to the position opposite to.

  In the fourth algorithm based on this concept, among the magnetic sensors 1, 2, and 3, for example, the magnetic sensor 1 is used as a reference magnetic sensor, and each time a detection signal is output from the magnetic sensor 1, The signal value corresponding to the detection signal output from one of the magnetic sensor 2 and the magnetic sensor 3 immediately after the detection signal is output from the magnetic sensor 1 last time, and immediately before the detection signal is output from the magnetic sensor 1 this time. It is determined whether the signal value corresponding to the detection signal output from either the magnetic sensor 2 or the magnetic sensor 3 is a predetermined signal value, and the rotating shaft 150 makes one rotation based on the determination result. Determine whether or not. The information that needs to be stored in order to realize the fourth algorithm is two signal values.

  The rotation determination circuit 62 of the circuit unit 61 that implements such a fourth algorithm includes a determination processing unit 63 and a detection signal storage unit 64, as shown in FIG.

  The determination processing unit 63 is an arithmetic processing circuit that performs rotation determination processing according to the above-described fourth algorithm, and is output from the magnetic sensors 1, 2, and 3 in substantially the same manner as the determination processing unit 33 in the first embodiment. A detection signal is received, and it is recognized which of the magnetic sensors 1, 2, and 3 the received detection signal is output from. The determination processing unit 63 can control the detection signal storage unit 64 to store, read, and erase signal values corresponding to the detection signals output from the magnetic sensors 1, 2, and 3. Further, the determination processing unit 63 recognizes the signal value corresponding to the detection signal output from the magnetic sensors 1, 2, and 3 and the signal value read from the detection signal storage unit 64, and the rotating shaft 150 is recognized based on the recognition result. It is determined whether or not the rotation shaft has made one rotation in the right direction and one rotation in the left direction. When the rotation shaft 150 makes one rotation in the right direction and when the rotation shaft 150 makes one rotation in the left direction, A different rotation judgment signal is output.

  The detection signal storage unit 64 is a storage circuit that stores signal values corresponding to the detection signals output from the magnetic sensors 1, 2, and 3. The detection signal storage unit 64 has a storage capacity capable of storing at least two signal values simultaneously.

  14 and 15 show specific operations of the circuit unit 61 according to the fourth algorithm. For convenience of explanation, similarly to the first embodiment described above, the signal values corresponding to the detection signals output from the magnetic sensors 1, 2, and 3 are “1”, “2”, and “3”, respectively. In addition, the determination processing unit 63 stores two signal values in the detection signal storage unit 64 at the same time. These two signal values are handled as one bit string (hereinafter referred to as “signal value array”) consisting of 4 bits when expressed in binary. That is, one of the two signal values is assigned to a first region in the signal value array (for example, the upper 2 bits of a 4-bit bit string), and the other of the two signal values is assigned. It is assumed that the signal value is assigned to a second region (for example, lower 2 bits of a 4-bit bit string) in the signal value array.

  In the table shown in FIG. 15, the leftmost first column indicates the step number as in FIG. 6, and the second column indicates the signal value corresponding to the detection signal. The third column shows the signal value array before processing by the determination processing unit 63, the fourth column shows the processing contents of the signal value array by the determination processing unit 63, and the fifth column shows the signal after processing by the determination processing unit 63 A value array is shown. In addition, the sixth column in FIG. 15 indicates the determination result by the determination processing unit 63, and the rightmost seventh column indicates the count value after the processing by the count processing unit 36.

  Step S61 in FIG. 15 is an initial state. In the initial state, the output magnet 16 is at a position facing the magnetic sensor 1 (see FIG. 14). The detection signal storage unit 64 stores “00” as the initial value of the signal value array.

  In step S62, when the movable unit 13 rotates 120 degrees to the right from the initial state as the rotation shaft 150 rotates in the right direction, and when a detection signal is output from the magnetic sensor 2, the determination processing unit 63 The signal value array “00” stored in the detection signal storage unit 64 is read, and the signal value “2” (“10” in binary) corresponding to the detection signal output this time from the magnetic sensor 2 is stored in the signal value array. Enter the first area. As a result, the signal value array becomes “02” (“0010” in binary). Subsequently, the determination processing unit 63 stores (overwrites) the signal value array in the detection signal storage unit 64.

  Thus, immediately after the movable unit 13 starts rotating from the initial state, the determination processing unit 63 sets the signal value corresponding to the detection signal output from either the magnetic sensor 2 or the magnetic sensor 3 to the signal value array. The signal value array is stored in the detection signal storage unit 64 in the first region. Further, as will be described later, the determination processing unit 63 also includes the magnetic sensor 2 and the magnetic sensor immediately after the output magnet 16 passes the vicinity of the magnetic sensor 1, that is, immediately after the detection signal is output from the magnetic sensor 1. 3, the signal value corresponding to the detection signal output from any one of 3 is input to the first region in the signal value array, and the signal value array is stored in the detection signal storage unit 64. On the other hand, as will be described later, the determination processing unit 63 outputs the signal value corresponding to the detection signal output from either the magnetic sensor 2 or the magnetic sensor 3 at the second time in the signal value array at other times. The signal value array is stored in the detection signal storage unit 64.

  In step S63, when the rotation of the rotation shaft 150 in the right direction is continued and the movable unit 13 is rotated 120 degrees in the right direction from the state in step S62, and the detection signal is output from the magnetic sensor 3, the determination is made. The processing unit 63 reads the signal value array “02” stored in the detection signal storage unit 64 and outputs a signal value “3” (“11” in binary) corresponding to the detection signal output from the magnetic sensor 3 this time. Put in the second region in the signal value array. As a result, the signal value array is “32” (“1110” in binary). Subsequently, the determination processing unit 63 stores the signal value array in the detection signal storage unit 64.

  In step S64, when the rotation of the rotation shaft 150 continues in the right direction, the movable unit 13 rotates 120 degrees in the right direction from the state of step S63, and the detection signal is output from the magnetic sensor 1. The processing unit 63 reads the signal value array “32” stored in the detection signal storage unit 64, and whether or not the rotation shaft 150 has made one rotation rightward or leftward based on the signal value array “32”. Determine. That is, when the detection signal is output from the magnetic sensor 1 serving as a reference among the magnetic sensors 1, 2, and 3, the determination processing unit 63 determines whether or not the rotating shaft 150 has made one rotation in the right or left direction. Perform the process. In this determination processing, the determination processing unit 63 determines that the rotation shaft 150 has made one right turn when the signal value array is “32”, and when the signal value array is “23”, the rotation shaft 150. Is determined to have made one rotation in the left direction. If the signal value array is other than these, the determination processing unit 63 determines that the rotating shaft 150 does not make one rotation. Since the signal value array is “32” in step S64, the determination processing unit 63 determines that the rotation shaft 150 has made one rotation in the right direction, and outputs a rotation determination signal indicating that. Then, the determination processing unit 63 deletes the read signal value array “32” and stores the signal value array “00” in the detection signal storage unit 64. Further, when the rotation determination signal is output from the determination processing unit 63, the count processing unit 36 reads the count value from the count value storage unit 38 in response to this, increases the read count value by 1, and increases the 1 The count value thus stored is stored (overwritten) in the count value storage unit 38.

  In step S65, when the rotation of the rotating shaft 150 continues in the right direction, the movable portion 13 rotates 120 degrees in the right direction from the state in step S64, and thereby the detection signal is output from the magnetic sensor 2. The determination processing unit 63 performs the same process as in step S62. As a result, the signal value array stored in the detection signal storage unit 64 is “02”.

  In step S66, the rotation of the rotating shaft 150 in the right direction continues, and accordingly, the movable portion 13 rotates 120 degrees in the right direction from the state in step S65, whereby the detection signal is output from the magnetic sensor 3. The determination processing unit 63 performs the same process as in step S63. As a result, the signal value array stored in the detection signal storage unit 64 is “32”.

  In step S67, the rotation direction of the rotary shaft 150 is reversed from the right direction to the left direction, and accordingly, the movable portion 13 is rotated 120 degrees in the left direction from the state of step S66, whereby the detection signal is output from the magnetic sensor 2. When output, the determination processing unit 63 reads the signal value array “32” stored in the detection signal storage unit 64 and outputs the signal value “2” corresponding to the detection signal output this time from the magnetic sensor 2 as the signal value. Put in the second region in the sequence. As a result, the signal value array becomes “22”. Subsequently, the determination processing unit 63 stores the signal value array in the detection signal storage unit 64.

  In step S68, the rotation direction of the rotating shaft 150 returns from the left direction to the right direction, and accordingly, the movable portion 13 rotates 120 degrees to the right from the state in step S67, thereby outputting a detection signal from the magnetic sensor 3. When the determination is made, the determination processing unit 63 reads the signal value array “22” stored in the detection signal storage unit 64 and sets the signal value “3” corresponding to the detection signal output this time from the magnetic sensor 3 to the signal value array. Put in the second area inside. As a result, the signal value array becomes “32”. Subsequently, the determination processing unit 63 stores the signal value array in the detection signal storage unit 64.

  In step S69, the rotation direction of the rotating shaft 150 is reversed again from the right direction to the left direction, and accordingly, the movable portion 13 rotates 120 degrees in the left direction from the state of step S68, thereby detecting the detection signal from the magnetic sensor 2. Is output, the determination processing unit 63 performs the same processing as in step S67. As a result, the signal value array stored in the detection signal storage unit 64 is “22”.

  In Step S70, the rotation of the rotation shaft 150 in the left direction is continued, and accordingly, the movable portion 13 is rotated 120 degrees in the left direction from the state in Step S69, and thereby the detection signal is output from the magnetic sensor 1. The determination processing unit 63 reads the signal value array “22” stored in the detection signal storage unit 64 and, based on the read signal value array, whether or not the rotation shaft 150 has made one rotation rightward or leftward. Determine whether. Since the signal value array is “22” in step S <b> 70, the determination processing unit 63 determines that the rotating shaft 150 has not made one rotation. In this case, the determination processing unit 63 does not output a rotation determination signal. Therefore, the count processing unit 36 does not operate. Then, the determination processing unit 63 erases the read signal value array “22” and stores the signal value array “00” in the detection signal storage unit 64.

  Further, the rotation shaft 150 rotates about 30 degrees to 110 degrees in the right direction and 30 degrees to 110 degrees in the left direction from the state of step S70 (a state where the output magnet 16 is in a position facing the magnetic sensor 1). When the rotation of the degree is repeated, the output magnet 16 continuously approaches and separates from the magnetic sensor 1, so that the detection signal is continuously received from the magnetic sensor 1 as shown in steps S71 and S72. Is output. In this case, the determination processing unit 63 reads the signal value array “00” stored in the detection signal storage unit 64 every time a detection signal is output from the magnetic sensor 1 in order to recognize this state. Neither the process of entering a new value into the value array nor the process of storing the signal value array in the detection signal storage unit 64 is performed.

  Furthermore, according to the rightward or leftward rotation of the movable unit 13 accompanying the rotation of the rotation shaft 150 in the rightward or leftward direction, the determination processing unit 63 performs processing subsequent to step S73.

  As described above, according to the circuit unit 61 of the fourth embodiment of the present invention, as with the circuit units 25, 41, 51 according to the first to third embodiments, the rotation determination circuit 62, the counting circuit 32, The power consumption can be reduced by operating the counting circuit 32 only when the rotation determination signal is output from the rotation determination circuit 62. Furthermore, according to the circuit unit 61 according to the fourth embodiment, the storage capacity of the detection signal storage unit 64 can be reduced to 4 bits, and the number of processes related to the rotation determination of the determination processing unit 62 is reduced. be able to. Therefore, power consumption can be further reduced.

(Other embodiments)
In the rotation detection device according to each of the embodiments described above, as shown in FIG. 3, a case where three magnets, that is, a standby magnet 15, an output magnet 16, and a standby magnet 17 are provided in the outer peripheral portion of the movable portion 13 in the circumferential direction. As an example, the present invention is not limited to this. As shown in FIG. 16, the columnar magnetic body may be divided into two, the standby magnet 71 may be formed by one magnetic body, and the output magnet 72 may be formed by the other magnetic body.

  In the rotation detection device according to each of the above-described embodiments, as shown in FIG. 3, the movable magnet 13 is provided with the standby magnet 15, the output magnet 16, and the standby magnet 17, and the magnetic sensors 1 and 2 are disposed around the movable portion 13. 3, the standby magnet 15, the output magnet 16, and the standby magnet 17 move with the rotation of the rotary shaft 150, and the magnetic sensors 1, 2, and 3 do not move. Not limited to this. As shown in FIG. 17, the magnetic sensors 1, 2, and 3 are provided on the movable portion 73, and the standby magnet 15, the output magnet 16, and the standby magnet 17 are provided around the movable portion 73. It is good also as a structure which moves with the rotation of the rotating shaft 150, and the standby magnet 15, the output magnet 16, and the standby magnet 17 do not move.

  In the rotation detection device according to each of the embodiments described above, as shown in FIGS. 2 and 3, each of the standby magnet 15, the output magnet 16, and the standby magnet 17 is a rod-shaped magnet, and the longitudinal direction of these magnets, The standby magnet 15, the output magnet 16, the standby magnet 17, and the magnetic sensors 1, 2, and 3 are arranged so that the longitudinal directions of the magnetic elements 21 of the magnetic sensors 1, 2, and 3 are parallel to each other. The present invention is not limited to this. As in the rotation detection device 110 shown in FIG. 18, each of the standby magnet, the output magnet, and the standby magnet is constituted by a pair of magnets 111 and 112, and one of the pair of magnets 111 and 112 is a magnet 111. Is arranged on one end side of the magnetic element 21, the other magnet 112 is arranged on the other end side of the magnetic element 21, and the magnets 111, 112 are arranged so that the different magnetic poles of the one magnet 111 and the other magnet 112 face each other. It is good also as a structure which sets each direction of these.

  Further, in the rotation detecting device according to each of the above-described embodiments, as shown in FIGS. 2 and 3, the longitudinal direction of the bar-shaped standby magnet 15, the output magnet 16, the standby magnet 17, and the magnetic sensors 1, 2, and 3. The standby magnet 15, the output magnet 16, the standby magnet 17, and the magnetic sensors 1, 2, and 3 are arranged so that the longitudinal direction of the magnetic element 21 is parallel to the axial direction of the rotary shaft 150. Not exclusively. As in the rotation detection device 120 shown in FIG. 19, the longitudinal direction of the standby magnet 15, the output magnet 16, the standby magnet 17, and the longitudinal direction of the magnetic element 21 of the magnetic sensors 1, 2, 3 are the axial direction of the rotating shaft 150. The standby magnet 15, the output magnet 16, the standby magnet 17, and the magnetic sensors 1, 2, and 3 may be arranged so as to be perpendicular to each other.

  Moreover, in each embodiment mentioned above, although the case where the three magnetic sensors 1, 2, and 3 were provided was mentioned as an example, the number of magnetic sensors is not restricted to three, Four or more may be sufficient. Increasing the number of magnetic sensors increases the storage capacity of the storage unit and the number of processes related to rotation determination, but can improve detection accuracy, accuracy, and reliability.

  Moreover, in each embodiment mentioned above, although the rotation detection apparatus was mentioned as an example as a motion detection apparatus of this invention, this invention is not limited to this. The present invention can also be applied to a circular motion detection apparatus 200 that detects the number of rounds in consideration of the state of the circular motion of the detected object, for example, the rotational movement direction of the detected object, as shown in FIG. The circular motion detection device 200 includes magnetic sensors 201, 202, 203, and 204 similar to the magnetic sensors 1, 2, and 3 of the rotation detection device 100, the standby magnet 15, the output magnet 16, and the standby magnet 17 of the rotation detection device 100. And a standby magnet 205, an output magnet 206, and a standby magnet 207. The detected object of the circular motion detection device 200 is, for example, a belt 211 of a belt conveyor that forms a closed loop. The standby magnet 205, the output magnet 206, and the standby magnet 207 are attached to the belt 211. When the belt 211 makes a revolving motion, the standby magnet 205 moves accordingly. On the other hand, the magnetic sensors 201, 202, 203, 204 are arranged so as not to move around the belt 211. Further, the standby magnet 205, the output magnet 206, and the standby magnet 207 are arranged with a distance Dc, and the distance Dc is the distance Dd, De, Df, Dg of each of the magnetic sensors 201, 202, 203, 204. Smaller than the minimum distance Df. According to such a circular motion detection device 200, the circular motion detection device 200 can be reduced in size, weight, and cost without impairing the accuracy of detection of the number of rotations in consideration of the rotational movement direction of the belt 211. I can. The belt 211 orbits on a quadrangular track, but the shape of the orbit of the circular motion is not limited to a quadrangle, and may be a triangle, an ellipse, a track type, or the like.

  Further, the present invention can be appropriately changed without departing from the spirit or idea of the invention which can be read from the claims and the entire specification, and a motion detection apparatus accompanying such a change is also a technical idea of the present invention. include.

1, 2, 3, 201, 202, 203, 204 Magnetic sensor (magnetic field detector)
13, 73 Movable part 15, 17, 71, 205, 207 Standby magnet (magnetic field generating part)
16, 72, 111, 112, 206 Output magnet (magnetic field generator)
21 Magnetic element 22 Coil 25, 41, 51, 61 Circuit unit (motion detection circuit)
31, 42, 52, 62 Rotation determination circuit 32 Count circuit 33, 43, 53, 63 Determination processing unit 34, 44, 54, 64 Detection signal storage unit 36 Count processing unit 38 Count value storage unit 39 Power supply voltage generation circuit 45 Rotation Quantity storage unit 55 Rotation amount substitution value storage unit 100, 110, 120 Rotation detection device (motion detection device)
150 Rotating shaft (Detected object)
200 Orbital motion detector (motion detector)
211 belt (object to be detected)

Claims (8)

A motion detection device for detecting a rotational motion or a circular motion of a detected object,
A movable part that rotates or circulates in response to the rotational motion or circular motion of the detected object;
A first magnetic field generator for generating a first magnetic field in which the direction of the magnetic field is the first direction;
A second magnetic field generating unit for generating a second magnetic field in which the direction of the magnetic field is a second direction opposite to the first direction;
Magnetized in the first direction by the first magnetic field when the first magnetic field generator approaches, and in the second direction by the second magnetic field when the second magnetic field generator approaches At least three magnetic field detectors that output a detection signal generated by an electromotive force generated when the magnetization direction changes between the first direction and the second direction;
A motion detection circuit that detects a state of rotational motion or circular motion of the detected object based on a detection signal output from each magnetic field detector;
The first magnetic field generation unit and the second magnetic field generation unit are disposed at a predetermined interval in the circumferential direction on the outer peripheral portion of the movable unit,
The at least three magnetic field detectors are in the vicinity of the outer peripheral part of the movable part, and the predetermined distance is along the locus of the outer peripheral part of the movable part when the movable part rotates or rotates. The motion detection device is characterized by being arranged with a large interval. A motion detection device for detecting a rotational motion or a circular motion of a detected object,
A movable part that rotates or circulates in response to the rotational motion or circular motion of the detected object;
A first magnetic field generator for generating a first magnetic field in which the direction of the magnetic field is the first direction;
A second magnetic field generating unit for generating a second magnetic field in which the direction of the magnetic field is a second direction opposite to the first direction;
Magnetized in the first direction by the first magnetic field when the first magnetic field generator approaches, and in the second direction by the second magnetic field when the second magnetic field generator approaches At least three magnetic field detectors that output a detection signal generated by an electromotive force generated when the magnetization direction changes between the first direction and the second direction;
A motion detection circuit that detects a state of rotational motion or circular motion of the detected object based on a detection signal output from each magnetic field detector;
The first magnetic field generation unit and the second magnetic field generation unit are in the vicinity of the outer peripheral part of the movable part, and the locus of the outer peripheral part of the movable part when the movable part rotates or rotates. Are arranged at predetermined intervals along
The motion detection device according to claim 1, wherein the at least three magnetic field detection units are arranged on the outer peripheral portion of the movable portion with a larger interval in the circumferential direction than the predetermined interval.   The motion detection apparatus according to claim 1, wherein each of the magnetic field detection units includes a magnetic element that generates a large Barkhausen effect and a coil wound around the magnetic element. A power supply voltage generation circuit that generates a power supply voltage from a detection signal output from each of the magnetic field detection units;
The motion detection device according to claim 1, wherein the motion detection circuit is operated by a power supply voltage generated by the power supply voltage generation circuit. The motion detection circuit is a circuit that detects a state of rotational motion of the detected object based on a detection signal output from each magnetic field detection unit,
The motion detection circuit includes:
It is determined whether or not the detected object has made one rotation based on the detection signal output from each of the magnetic field detection units, and every time the detected object makes one rotation, the detected object has made one rotation. A rotation determination circuit that outputs a rotation determination signal indicating;
5. The motion detection device according to claim 1, further comprising a counting circuit that counts the number of rotations of the detected object based on a rotation determination signal output from the rotation determination circuit. . One of the at least three magnetic field detection units is a reference magnetic field detection unit, and each remaining magnetic field detection unit is a non-reference magnetic field detection unit,
The rotation determination circuit detects the detection signal output from any one of the non-reference magnetic field detection units immediately after the detection signal is output from the reference magnetic field detection unit last time each time a detection signal is output from the reference magnetic field detection unit. A signal and a detection signal output from any one of the non-reference magnetic field detection units immediately before the detection signal is output from the reference magnetic field detection unit this time are determined to be predetermined detection signals, respectively, 6. The motion detection apparatus according to claim 5, wherein it is determined whether or not the detected object has made one rotation based on a determination result.   The rotation determination circuit compares the detection signal output this time with the detection signal output last time each time a detection signal is output from each of the magnetic field detection units, and based on the comparison result, 6. The motion detection device according to claim 5, wherein a rotation amount is detected, and it is determined whether or not the detection object has made one rotation based on a rotation amount of the detection object. The counting circuit includes:
A counting processing unit that counts the number of rotations of the detected object based on the rotation determination signal output from the rotation determination circuit, and outputs a count value indicating the number of rotations of the detected object in Gray code;
The motion detection device according to claim 5, further comprising: a count value storage unit that stores a count value output by the Gray code from the count processing unit.

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