JP2021117120A - Rotation detection device - Google Patents

Abstract

To provide means for suppressing an increase in the whole device size when a rotation detection device is fitted, in combination with other devices, to the device to be detected.SOLUTION: A rotation detection device 1 comprises: magnets 11-14 moving in a trajectory around the rotation axis A of a shaft 62 due to the rotation of the shaft 62, the magnets respectively forming a magnetic field differing in direction from each other; and magnetic sensors 21-23 for detecting the magnetic fields formed by each of the magnets 11-14 and arranged around the rotation axis A so as not to move along with the rotation of the shaft 62 and having a magnetic wire rod 25. The magnetic sensors 21-23 are arranged at mutually different positions in the direction of rotation of the shaft 62 so that the extension directions of the magnetic wire rods 25 are nonparallel to the rotation axis A, and also arranged separately on the surface and the reverse side 41B of a substrate 41 that is arranged on a plane crossing the rotation axis A.SELECTED DRAWING: Figure 3

Description

The present invention relates to a rotation detection device that detects rotation of a rotating body using magnetism.

For example, as a device for detecting the rotation of a rotating body such as a shaft of a motor, a magnetic rotation detection device using a magnetic wire material that produces a large Barkhausen effect is known (see Patent Document 1). This rotation detection device includes at least a pair of magnets that form magnetic fields having different directions, and a magnetic sensor in which a coil is provided around a magnetic wire that produces a large Barkhausen effect. The pair of magnets are fixed to, for example, the outer peripheral portion of the rotating body, and move on a circular orbit around the rotation axis of the rotating body as the rotating body rotates. The magnetic sensor is arranged in the vicinity of the circular orbit in which the magnet moves so as not to move with the rotation of the rotating body. When a pair of magnets move on a circular orbit with the rotation of the rotating body, the pair of magnets alternately pass in the vicinity of the magnetic sensor. As a result, the direction of the magnetic field acting on the magnetic wire of the magnetic sensor changes with the rotation of the rotating body. The magnetic wire has a property that the magnetization direction is rapidly reversed when the direction of the magnetic field acting on the magnetic wire is changed, that is, a property of producing a large Barkhausen effect. Therefore, every time the direction of the magnetic field acting on the magnetic wire changes with the rotation of the rotating body, the magnetization direction of the magnetic wire suddenly reverses, and a pulse signal is output from the coil by electromagnetic induction. The rotation speed or rotation angle of the rotating body is detected by this pulse signal.

Further, as another device for detecting the rotation of the rotating body, an optical encoder is known. The optical encoder includes, for example, a light emitting element, a light receiving element, and a disk-shaped chord wheel. The chord wheel is fixed to the rotating body and rotates together with the rotating body. The light emitting element and the light receiving element are arranged in the vicinity of the cord wheel so as not to rotate together with the rotating body. There are two types of chord wheels: transparent chord wheels and reflective chord wheels. In the transmissive chord wheel, a large number of slits are arranged in a portion where the light emitted from the light emitting element during rotation is irradiated. In the reflective chord wheel, a large number of reflective regions and non-reflective regions are alternately arranged in a portion irradiated with light emitted from a light emitting element during rotation. When the chord wheel rotates together with the rotating body and light is emitted from the light emitting element to the chord wheel, a pulsed detection light is formed by the arrangement of the slits of the chord wheel or the arrangement of the reflective region and the non-reflective region. The detection light is input to the light receiving element. The rotation speed or rotation angle of the rotating body is detected by the pulsed detection light.

Japanese Unexamined Patent Publication No. 2019-200101

The magnetic rotation detection device is characterized in that it operates without a power source. Further, the optical encoder has a feature that the rotation angle of the rotating body can be detected in detail. By combining the magnetic rotation detection device and the optical encoder and attaching them to a device to be detected such as a motor, the magnetic rotation detection device detects the rotation of the rotating body when the power is off, and the magnetic type when the power is on. The rotation detection device and the optical encoder make it possible to detect the rotation of the rotating body with high accuracy.

However, in this case, since both the magnetic rotation detection device and the optical encoder are attached to the detected device, the entire device including the magnetic rotation detection device, the optical encoder, and the detected device may become large in size. be.

An object of the present invention is a rotation detection device using a magnetic wire rod, and when the rotation detection device is attached to the detected device in combination with another device, the rotation detection device, the other device, and the detected device It is an object of the present invention to provide a rotation detection device capable of suppressing an increase in the size of the entire device including the above.

In order to solve the above problems, the rotation detection device of the present invention is a rotation detection device that detects the rotation of a rotating body, forms magnetic fields having different directions, and rotates with the rotation of the rotating body. At least a pair of magnetic field forming portions that move on an orbit around a rotation axis of the body, and at least a pair of magnetic wire rods that are arranged around the rotation axis so as not to move with the rotation of the rotating body. The rotating body includes a plurality of magnetic field detecting units for detecting the magnetic fields formed by the magnetic field forming units of the above, and the plurality of magnetic field detecting units are such that the extension direction of the magnetic wire is non-parallel to the rotation axis. Are arranged at different positions in the rotation direction of the above, and are separately arranged on two or more planes intersecting the rotation axis at different positions in the direction of the rotation axis.

According to the present invention, when a rotation detection device using a magnetic wire is attached to a device to be detected in combination with another device, the entire device including the rotation detection device, the other device, and the device to be detected becomes large. Can be suppressed.

It is explanatory drawing which shows the rotation detection apparatus, the optical encoder and the motor of embodiment of this invention. It is explanatory drawing which shows the state which the rotation detection device, the optical encoder and the motor in FIG. 1 were seen from the direction of the rotation axis (upper part in FIG. 1). It is explanatory drawing which shows the state which the cross section of the rotation detection apparatus and the shaft cutting line III-III in FIG. 1 was seen from the direction of the rotation axis (lower in FIG. 1). It is explanatory drawing which shows the arrangement of the magnet in the rotation detection apparatus of embodiment of this invention, and the modification | modification thereof. It is a perspective view which shows the magnetic sensor in the rotation detection apparatus of embodiment of this invention. It is explanatory drawing which shows the operation of the rotation detection apparatus of embodiment of this invention. It is explanatory drawing which shows the optical encoder. It is explanatory drawing which shows the use state of the substrate in the rotation detection apparatus of embodiment of this invention. It is explanatory drawing which shows the rotation detection apparatus, the optical encoder and the motor of another embodiment of this invention.

FIG. 1 shows a magnetic rotation detection device 1, an optical encoder 51, and a motor 61 as a detection device according to an embodiment of the present invention. As shown in FIG. 1, the motor 61 has a shaft 62 as a rotating body. The rotation detection device 1 and the optical encoder 51 are provided around the shaft 62, and detect the rotation of the shaft 62, respectively. Note that A in FIG. 1 indicates the rotation axis of the shaft 62. According to the composite device 71 shown in FIG. 1 including the rotation detection device 1, the optical encoder 51, and the motor 61, the rotation detection device 1 can be used to detect the rotation of the shaft 62 when the power is off, and when the power is on, the rotation of the shaft 62 can be detected. The rotation of the shaft 62 can be detected with high accuracy by using the rotation detection device 1 and the optical encoder 51.

FIG. 2 shows a state in which the rotation detection device 1, the optical encoder 51, and the motor 61 in FIG. 1 are viewed from the direction of the rotation axis A (upper side in FIG. 1). FIG. 3 shows a state in which the cross section of the cutting line III-III of the rotation detection device 1 and the shaft 62 in FIG. 1 is viewed from the direction of the rotation axis A (lower side in FIG. 1). FIG. 4A shows a shaft 62 in which magnets 11 to 14 are arranged in the rotation detection device 1 of the present embodiment. FIG. 4B shows a modified example of the arrangement of the magnets of the rotation detection device 1. FIG. 5 shows the magnetic sensor 21.

The rotation detection device 1 has four magnets 11, 12, 13, 14 (two pairs of magnetic field forming parts), three magnetic sensors 21, 22, 23 (three magnetic field detecting parts), and three yoke pairs 31, 32. It includes 33 (three magnetic field control units) and a substrate 41.

The magnets 11 to 14 are permanent magnets, and are fixed to the outer peripheral surface of the shaft 62 as shown in FIG. Further, as shown in FIG. 2, when the rotation detection device 1 is viewed from the direction of the rotation axis A, the magnets 11 to 14 are arranged around the rotation axis A at an interval of 90 degrees. The magnets 11 to 14 move on the orbit B around the rotation axis A as the shaft 62 rotates.

Further, the magnet 11 and the magnet 13 are fixed to the shaft 62 so that the outer surface in the radial direction when viewed from the rotation axis A is the north pole. Further, the magnet 12 and the magnet 14 are fixed to the shaft 62 so that the outer surface in the radial direction when viewed from the rotation axis A is the S pole. Further, the magnets 11 to 14 are arranged in the order of, for example, the magnets 11, 12, 13, and 14 in the circumferential direction so that the polarities of the adjacent magnets are opposite in the circumferential direction of the shaft 62.

Further, as shown in FIG. 4A, each magnet 11 to 14 is long in the direction of the rotation axis A (vertical direction in FIG. 4). As shown in FIG. 1, the magnets 11 to 14 pass through the through hole 42 of the substrate 41, the upper portion of the magnets 11 to 14 is located above the substrate 41, and the lower portion of the magnets 11 to 14 is the substrate. It is located below 41. As a result, the magnetic sensor 21 arranged on the front surface 41A of the substrate 41 and the two magnetic sensors 22 and 23 arranged on the back surface 41B of the substrate 41 both face the orbit B on which the magnets 11 to 14 move. There is. In FIG. 4A, the polarities of the magnetic poles on the outer surface in the radial direction seen from the rotation axis A are the same between the upper part and the lower part of the magnet 12, and both are S poles. The same applies to the magnet 14. Further, the polarities of the magnetic poles on the outer surface in the radial direction seen from the rotation axis A are the same in the upper part and the lower part of the magnet 13, and both are N poles. The same applies to the magnet 11.

As shown in the modified example of FIG. 4B, the magnet 12 may be divided into two magnet pieces 12A and 12B, and the magnet 13 may be divided into two magnet pieces 13A and 13B, respectively. The same applies to the magnet 11 and the magnet 14.

The magnetic sensors 21 to 23 are sensors that detect the magnetic fields formed by the magnets 11 to 14, respectively, by utilizing the large Barkhausen effect. As shown in FIG. 2, the magnetic sensor 21 is arranged on the front surface 41A of the substrate 41, and as shown in FIG. 3, the magnetic sensors 22 and 23 are arranged on the back surface 41B of the substrate 41. The magnetic sensor 21 is a specific example of the first magnetic field detection unit, the magnetic sensor 22 is a specific example of the second magnetic field detection unit, and the magnetic sensor 23 is a specific example of the third magnetic field detection unit.

As shown in FIG. 5, the magnetic sensor 21 has a magnetic wire 25, a coil 26, and a bobbin 27. The magnetic wire 25 is a large Barkhausen element. Specifically, the magnetic wire 25 is a linear ferromagnet that produces a large Barkhausen effect and has uniaxial anisotropy. The magnetic wire 25 is called a composite magnetic wire. The magnetic wire 25 can be formed, for example, by twisting a semi-hard magnetic wire containing iron and cobalt. The magnetic wire 25 is arranged inside the shaft of the bobbin 27 formed of a non-magnetic material such as resin. The coil 26 is provided on the outer peripheral side of the magnetic wire 25. For example, the coil 26 is formed by winding an enamel wire around the outer peripheral side of the shaft portion of the bobbin 27 in which the magnetic wire rod 25 is arranged inside. The magnetic sensor 22 and the magnetic sensor 23 also have the same configuration as the magnetic sensor 21.

The length of the magnetic wire 25 is, for example, about 10 mm to 20 mm. In each of the magnetic sensors 21 to 23, the magnetic wire 25 is arranged inside the bobbin 27 in a linearly extended state. Depending on the length of the magnetic wire 25, the length of each magnetic sensor 21 to 23 is, for example, about 10 mm to 20 mm.

The magnetic sensors 21 to 23 are arranged around the rotation shaft A so as not to move with the rotation of the shaft 62. Specifically, as shown in FIGS. 2 and 3, the magnetic sensors 21 to 23 are fixed to the substrate 41, respectively. The substrate 41 is arranged on a plane orthogonal to the rotation axis A. As a result, the front surface 41A and the back surface 41B of the substrate 41 are arranged on two planes orthogonal to the rotation axis A at different positions in the direction of the rotation axis A. The substrate 41 is formed in a disk shape, for example, a through hole 42 is provided in the center thereof, and a shaft 62 is inserted into the through hole 42. The inner diameter of the through hole 42 is larger than the outer diameter of the shaft 62, and the shaft 62 is not in contact with the substrate 41. Further, the substrate 41 is fixed to, for example, the housing 63 of the motor 61 via a support bracket (not shown).

Further, the magnetic sensors 21 to 23 are arranged so that the extension direction of the magnetic wire 25 is not parallel to the rotation axis A. Specifically, the magnetic sensors 21 to 23 are arranged so that the plane including the axis of the magnetic wire 25 is orthogonal to the rotation axis A. The axis of the magnetic wire 25 refers to a straight line penetrating the center of the cross section of the magnetic wire 25 in the extending direction of the magnetic wire 25.

Further, as shown in FIGS. 2 and 3, when the rotation detection device 1 is viewed from the direction of the rotation axis A, in the magnetic sensors 21 to 23, the central portion of the axis of the magnetic wire 25 in the extension direction is the rotation axis. It is arranged so as to be in contact with the circumference of the circle C centered on A. Further, when the rotation detection device 1 is viewed from the direction of the rotation axis A, the magnetic sensors 21 to 23 are arranged on the outer peripheral side of the trajectory B on which the magnets 11 to 14 move. Further, the magnetic sensors 21 to 23 are arranged at different positions in the rotation direction of the shaft 62. Specifically, when the rotation detection device 1 is viewed from the direction of the rotation axis A, the magnetic sensors 21 to 23 are arranged around the shaft 62 at an interval of 60 degrees.

Further, the magnetic sensors 21 to 23 are separately arranged on two or more planes intersecting the rotation axis A at different positions in the direction of the rotation axis A. Specifically, the magnetic sensor 21 is arranged on the first plane of the first plane and the second plane that intersect with the rotation axis A at different positions in the direction of the rotation axis A, and the magnetic sensor 22 and The magnetic sensor 23 is arranged on a second plane. More specifically, in the present embodiment, the magnetic sensor 21 is arranged on the surface 41A of the substrate 41 as shown in FIG. 2, and the magnetic sensor 22 and the magnetic sensor 23 are arranged on the substrate as shown in FIG. It is arranged on the back surface 41B of 41. That is, in the present embodiment, the front surface 41A and the back surface 41B of the substrate 41 correspond to the two or more planes, the front surface 41A of the substrate 41 corresponds to the first plane, and the back surface 41B of the substrate 41 corresponds to the above. Corresponds to the second plane. In the present embodiment, the front surface 41A of the substrate 41 is the surface of the substrate 41 that faces in opposite directions and is far from the motor 61, and the back surface 41B of the substrate 41 is the surface of the substrate 41. Of the above two wide surfaces of the substrate 41, the surface closer to the motor 61.

Further, when the rotation detection device 1 is viewed from the direction of the rotation axis A, of the magnetic sensors 21 to 23, two magnetic sensors adjacent to each other in the rotation direction of the shaft 62 partially overlap each other. Specifically, the magnetic sensors 21 to 23 are around the rotation axis A so that the magnetic sensor 22 is located on one side of the magnetic sensor 21 and the magnetic sensor 23 is located on the other side of the magnetic sensor 21. They are arranged side by side. Then, one end of the magnetic sensor 21 and one end of the magnetic sensor 22 overlap each other, and the other end of the magnetic sensor 21 and one end of the magnetic sensor 23 overlap each other. When the rotation detection device 1 is viewed from the direction of the rotation axis A, it means that one part and the other part "overlap". Here, the one part and the other part are the rotation axis A. It means that they face each other with the substrate 41 in between (the direction parallel to the rotation axis A).

Further, when the rotation detection device 1 is viewed from the direction of the rotation axis A, the magnetic wires 25 of the two magnetic sensors adjacent to each other in the rotation direction of the shaft 62 of the magnetic sensors 21 to 23 partially overlap each other. Specifically, one end of the magnetic wire 25 of the magnetic sensor 21 and one end of the magnetic wire 25 of the magnetic sensor 22 overlap each other, and the other end of the magnetic wire 25 of the magnetic sensor 21 and the magnetic wire 25 of the magnetic sensor 23 One end of the magnetism overlaps with each other.

The yoke pairs 31, 32, and 33 have a function of controlling the direction of the magnetic field formed by the magnets 11 to 14. Each yoke pair 31, 32, 33 has a pair of yoke pieces 35. Each yoke piece 35 is formed in a plate shape by, for example, a soft magnetic material such as pure iron, silicon steel, parolomy or an amorphous metal.

The yoke pairs 31, 32, and 33 are separately arranged so as to correspond to the magnetic sensors 21, 22, and 23 on two or more planes that intersect the rotation axis A at different positions in the direction of the rotation axis A. .. Specifically, the yoke pair 31 is arranged on the front surface 41A of the substrate 41, and the yoke pair 32 and the yoke pair 33 are arranged on the back surface 41B of the substrate 41.

As shown in FIG. 2, the yoke pair 31 is arranged between the magnetic sensor 21 and the trajectory B on which the magnets 11 to 14 move. Specifically, one yoke piece 35 of the yoke pair 31 is arranged between one end of the magnetic sensor 21 and the track B, and the other yoke piece 35 is the other end of the magnetic sensor 21 and the track B. It is placed between. Further, these two yoke pieces 35 are separated from each other. Further, each yoke piece 35 of the yoke pair 31 rises from the surface 41A of the substrate 41 in a direction orthogonal to the surface 41A (upper in FIG. 1).

As shown in FIG. 3, the yoke pair 32 is arranged between the magnetic sensor 22 and the orbit B. Specifically, one yoke piece 35 of the yoke pair 32 is arranged between one end of the magnetic sensor 22 and the track B, and the other yoke piece 35 is the other end of the magnetic sensor 22 and the track B. It is placed between. Further, these two yoke pieces 35 are separated from each other. Further, each yoke piece 35 of the yoke pair 32 rises from the back surface 41B of the substrate 41 in a direction orthogonal to the back surface 41B (downward in FIG. 1). The yoke pair 33 is arranged between the magnetic sensor 22 and the trajectory B on which the magnets 11 to 14 move. Further, as shown in FIG. 3, the pair of yoke pieces 35 of the yoke pair 33 are arranged in the same manner as the pair of yoke pieces 35 of the yoke pair 32.

Further, when the rotation detection device 1 is viewed from the direction of the rotation axis A, of the yoke pairs 31 to 33, two yoke pairs adjacent to each other in the rotation direction of the shaft 62 partially overlap each other. Specifically, as shown in FIG. 2, one yoke piece 35 of the yoke pair 31 partially overlaps the one yoke piece 35 of the yoke pair 32. Further, the other yoke piece 35 of the yoke pair 31 partially overlaps with the one yoke piece 35 of the yoke pair 33.

FIG. 6 shows the operation of the rotation detection device 1. FIG. 6 depicts six states of the rotation detection device 1 as viewed from above in FIG. That is, in FIG. 6, the shaft 62 is rotating clockwise, and the rotation detection device 1 on the upper left in FIG. 6 shows a state when the rotation angle of the shaft 62 reaches 0 °, and is to the right of the shaft 62. The rotation detection device 1 shows the state when the rotation angle of the shaft 62 reaches 30 °, and the rotation detection device 1 to the right of the rotation detection device 1 shows the state when the rotation angle of the shaft 62 reaches 60 °. There is. Further, the rotation detection device 1 at the lower left in FIG. 6 shows a state when the rotation angle of the shaft 62 reaches 90 °, and the rotation detection device 1 to the right of the rotation detection device 1 has a rotation angle of the shaft 62 of 120 °. The state when it reaches is shown, and the rotation detection device 1 on the right side shows the state when the rotation angle of the shaft 62 reaches 150 °. Further, W1 in FIG. 6 shows the waveform of the detection signal output from the magnetic sensor 21, W2 shows the waveform of the detection signal output from the magnetic sensor 22, and W3 shows the waveform of the detection signal output from the magnetic sensor 23. The waveform is shown.

The magnetic wire 25 possessed by each of the magnetic sensors 21 to 23 is affected by the large bulkhausen effect when the direction of the external magnetic field acting on the magnetic wire 25 changes and the strength of the external magnetic field reaches a certain threshold. It has the property that the magnetization direction is instantly reversed. When the magnetization direction of the magnetic wire 25 is instantly reversed, a sharp pulse is output by electromagnetic induction from the coil 26 provided on the outer peripheral side of the magnetic wire 25. Further, when the external magnetic field acting on the magnetic wire 25 changes from one direction to the other and the strength of the external magnetic field reaches a certain threshold, the magnetization direction of the magnetic wire 25 is reversed from one direction to the other. Then, for example, a positive pulse is output from the coil 26. Further, when the external magnetic field acting on the magnetic wire 25 changes in one direction from the other direction and the strength of the external magnetic field reaches a certain threshold value, the magnetization direction of the magnetic wire 25 changes in one direction from the other direction. Then, for example, a negative pulse is output from the coil 26.

In the rotation detection device 1, the magnets 11 to 14 move on the orbit B with the rotation of the shaft 62, so that the magnetic field acting on each magnetic wire 25 of the magnetic sensors 21 to 23 changes. For example, when the rotation angle of the shaft 2 reaches 0 degrees while the shaft 62 is rotating clockwise in FIG. 6, the magnet 11 and the magnet 14 approach the magnetic sensor 21. At this time, due to the magnetic fields formed by the magnet 11 and the magnet 14 (the magnetic field formed by the magnet 11 and the magnetic field formed by the magnet 14 combined), the magnetic wire 25 of the magnetic sensor 21 is shown in FIG. A magnetic field in the right direction acts. As a result, the magnetization direction of the magnetic wire 25 of the magnetic sensor 21 is reversed, and for example, a positive pulse P1 is output from the magnetic sensor 21. Further, the level of the pulse P1 can be increased by controlling the magnetic field by the yoke pair 31 so that the magnetic field lines from the magnet 11 to the magnet 14 pass through the magnetic wire rod 25 of the magnetic sensor 21 in the right direction.

Next, when the rotation angle of the shaft 2 reaches 30 degrees, the magnet 11 and the magnet 12 approach the magnetic sensor 22. At this time, due to the magnetic fields formed by the magnets 11 and 12, the magnetic wire 25 of the magnetic sensor 22 acts on the magnetic wire 25 in the diagonally downward direction to the left in FIG. As a result, the magnetization direction of the magnetic wire 25 of the magnetic sensor 22 is reversed, and for example, a negative pulse P2 is output from the magnetic sensor 22. Further, the level of the pulse P2 can be increased by controlling the magnetic field by the yoke pair 32 so that the magnetic field line from the magnet 11 to the magnet 12 passes through the magnetic wire material 25 of the magnetic sensor 22 in the diagonally downward direction to the left. ..

Next, when the rotation angle of the shaft 2 reaches 60 degrees, the magnet 11 and the magnet 14 approach the magnetic sensor 23. At this time, due to the magnetic fields formed by the magnets 11 and 14, respectively, a magnetic field in the diagonally downward right direction in FIG. 6 acts on the magnetic wire 25 of the magnetic sensor 23. As a result, the magnetization direction of the magnetic wire 25 of the magnetic sensor 23 is reversed, and for example, a positive pulse P3 is output from the magnetic sensor 23. Further, the level of the pulse P3 can be increased by controlling the magnetic field by the yoke pair 33 so that the magnetic field line from the magnet 11 to the magnet 14 passes through the magnetic wire material 25 of the magnetic sensor 23 in the diagonally downward direction to the right. ..

Next, when the rotation angle of the shaft 2 reaches 90 degrees, the magnet 11 and the magnet 12 approach the magnetic sensor 21. At this time, a magnetic field in the left direction in FIG. 6 acts on the magnetic wire 25 of the magnetic sensor 21 due to the magnetic fields formed by the magnets 11 and 12, respectively. As a result, the magnetization direction of the magnetic wire 25 of the magnetic sensor 21 is reversed, and for example, a negative pulse P4 is output from the magnetic sensor 21. Further, the level of the pulse P4 can be increased by controlling the magnetic field by the yoke pair 31.

Next, when the rotation angle of the shaft 2 reaches 120 degrees, the magnet 12 and the magnet 13 approach the magnetic sensor 22. At this time, due to the magnetic fields formed by the magnet 12 and the magnet 13, a magnetic field in the diagonally upward right direction in FIG. 6 acts on the magnetic wire 25 of the magnetic sensor 22. As a result, the magnetization direction of the magnetic wire 25 of the magnetic sensor 22 is reversed, and for example, a positive pulse P5 is output from the magnetic sensor 22. Further, the level of the pulse P5 can be increased by controlling the magnetic field by the yoke pair 32.

Next, when the rotation angle of the shaft 2 reaches 150 degrees, the magnet 11 and the magnet 12 approach the magnetic sensor 23. At this time, due to the magnetic fields formed by the magnet 11 and the magnet 12, a magnetic field in the diagonally upward left direction acts on the magnetic wire 25 of the magnetic sensor 23 in FIG. As a result, the magnetization direction of the magnetic wire 25 of the magnetic sensor 23 is reversed, and for example, a negative pulse P6 is output from the magnetic sensor 23. Further, the level of the pulse P6 can be increased by controlling the magnetic field by the yoke pair 33.

The pulses P1 to P6 output from the magnetic sensors 21 to 23 are output to, for example, a detection circuit (not shown) for magnetic detection provided on the substrate 41, and the rotation amount, rotation direction, etc. of the shaft 62 are generated by this detection circuit. Is calculated. As a method for calculating the amount of rotation and the direction of rotation of the shaft 62, for example, the method described in International Publication No. 2016/002437 can be used.

FIG. 7 shows an optical encoder 51. As shown in FIG. 7, the optical encoder 51 includes a code wheel 52 as an encoding plate that rotates with the rotation of the shaft 62 to generate detection light, and a photodetector 56 that detects the detection light. There is.

The chord wheel 52 is formed in a disk shape by, for example, a non-magnetic material such as resin. Further, an insertion hole 53 for attaching the cord wheel 52 to the shaft 62 is provided at the center of the cord wheel 52. The shaft 62 is inserted into the insertion hole 53. Further, a plurality of reflective portions 54 and a plurality of non-reflective portions 55 are provided on the surface 52A of the chord wheel 52. The reflective portions 54 and the non-reflective portions 55 are arranged alternately so as to draw a circle centered on the center Q (rotation axis A) of the chord wheel 52.

The light detection unit 56 is a unit including a light emitting element 57 and a light receiving element 58. The light emitting element 57 is, for example, a light emitting diode. The light receiving element 58 is, for example, a phototransistor, and performs photoelectric conversion.

As shown in FIG. 1, the code wheel 52 is arranged between the substrate 41 and the housing 63 of the motor 61, and the front surface 52A provided with the reflective portion 54 and the non-reflective portion 55 faces the back surface 41B of the substrate 41. It is attached to the shaft 62 so as to do so. Further, the chord wheel 52 is fixed to the shaft 62 and rotates together with the shaft 62.

Further, as shown by a broken line (hidden line) in FIG. 2, the chord wheel 52 is arranged between the yoke pair 32 and the yoke pair 33. Further, as shown in FIG. 1, the surface 52A of the chord wheel 52 is located above the tip end surface 35A (lower end surface in FIG. 1) of each yoke piece 35 of the yoke pair 32 and the yoke pair 33. That is, the chord wheel 52 is in the space sandwiched between the yoke pair 32 and the yoke pair 33. With this configuration, the distance between the substrate 41 and the chord wheel 52 can be reduced, and the dimensions of the structure in which the rotation detection device 1 provided around the shaft 62 and the optical encoder 51 are combined in the rotation axis A direction. Can be made smaller.

Further, the photodetector 56 is fixed to the back surface 41B of the substrate 41. Therefore, the photodetector 56 does not move with the rotation of the shaft 62. The light detection unit 56 is arranged so as to face the arrangement of the reflective unit 54 and the non-reflective unit 55 on the chord wheel 52.

In FIG. 7, while the shaft 62 is rotating, the irradiation light L1 emitted from the light emitting element 57 is emitted onto the arrangement of the reflecting portion 54 and the non-reflecting portion 55. As a result, the pulsed detection light L2 is generated. The generated detection light L2 is input to the light receiving element 58. The light receiving element 58 converts the detection light L2 into a pulse signal and outputs it. The pulse signal output from the light receiving element 58 is output to, for example, a detection circuit for light detection (not shown) provided on the substrate 41, and the rotation speed and rotation angle of the shaft 62 are calculated by this detection circuit. ..

FIG. 8A shows the usage state of the front surface 41A of the substrate 41, and FIG. 8B shows the usage state of the back surface 41B of the substrate 41. As shown in FIG. 8A, the surface 41A of the substrate 41 is divided into two regions R1 and R2. On the surface 41A of the substrate 41, the region R1 with fine hatching is the region used by the rotation detection device 1, and the region R2 with coarse hatching is the optical encoder 51 and other devices attached to the motor 61. Area of use. In the region R1, the components of the rotation detection device 1, specifically, the magnetic sensor 21 and the yoke pair 31 are arranged.

Further, as shown in FIG. 8B, the back surface 41B of the substrate 41 is divided into two regions R3 and R4. On the back surface 41B of the substrate 41, the region R3 with fine hatching is the region used by the rotation detection device 1, and the region R4 with coarse hatching is the optical encoder 51 and other devices attached to the motor 61. Area of use. Within the region R3, components of the rotation detection device 1, specifically, two magnetic sensors 22, 23 and two yoke pairs 32, 33 are arranged. A component of the optical encoder 51, specifically, a photodetector 56 is arranged in the region R4.

As described above, in the rotation detection device 1 of the present embodiment, the magnetic sensors 21 to 23 are arranged so that the extension direction of the magnetic wire 25 is not parallel to the rotation axis A. Specifically, the magnetic sensors 21 to 23 are arranged so that the plane including the axis of the magnetic wire 25 is orthogonal to the rotation axis A. With this configuration, as compared with the case where the magnetic sensors 21 to 23 are arranged so that the extension direction of the magnetic wire 25 is parallel to the rotation axis A, the dimensions of the rotation detection device 1 in the direction of the rotation axis A (FIG. 1). Dimension in the vertical direction) can be reduced.

Further, the magnetic sensors 21 to 23 are separately arranged on two or more planes intersecting the rotation axis A at different positions in the direction of the rotation axis A. Specifically, the magnetic sensors 21 to 23 are separately arranged in a first plane and a second plane that intersect the rotation axis A at different positions in the direction of the rotation axis A. More specifically, the magnetic sensors 21 to 23 are separately arranged on the front surface 41A and the back surface 41B of the substrate 41. With this configuration, of the magnetic sensors 21 to 23, two magnetic sensors adjacent to each other in the rotation direction of the shaft 62 are partially overlapped with each other when the rotation detection device 1 is viewed from the direction of the rotation axis A. Can be placed. Therefore, as shown in FIG. 8, the magnetic sensors 21 to 23 can be centrally arranged in a part of the substrate 41, and the area used for arranging the magnetic sensors 21 to 23 on the front surface 41A and the back surface 41B of the substrate 41. The areas of R1 and R3 can be reduced. As a result, the area of the front surface 41A (back surface 41B) of the substrate 41 is increased while sufficiently securing the areas R2 and R4 that can be used for arranging the optical encoder 51 and other devices on the front surface 41A and the back surface 41B of the substrate 41. It can be made smaller overall.

As described above, according to the rotation detection device 1 of the present embodiment, the size of the rotation detection device 1 in the direction of the rotation axis A can be reduced, and the optical encoder 51 and other devices can be mounted on the substrate 41. Since the area of the substrate 41 can be reduced while sufficiently securing the area that can be used for arrangement, the composite device 71 including the rotation detection device 1, the optical encoder 51, and the motor 61 can be miniaturized as a whole. can. That is, when the rotation detection device 1 is attached to the motor 61 in combination with the optical encoder 51 or the like, it is possible to prevent the entire device including the rotation detection device 1, the optical encoder 51 and the motor 61 from becoming large. can.

In particular, in the rotation detection device 1 of the present embodiment, of the magnetic sensors 21 to 23, the magnetic wire rods 25 of two magnetic sensors adjacent to each other in the rotation direction of the shaft 62 see the rotation detection device 1 from the direction of the rotation axis A. When they do, they partially overlap each other. By enlarging the portion where the adjacent magnetic sensors overlap each other in this way, the degree of aggregation of the arrangement of the magnetic sensors 21 to 23 can be increased, and the arrangement of the magnetic sensors 21 to 23 on the front surface 41A and the back surface 41B of the substrate 41 can be increased. The area of the regions R1 and R3 used for the above can be further reduced.

Further, in the rotation detection device 1 of the present embodiment, in the magnetic sensors 21 to 23, the magnetic sensor 22 is located on one side of the magnetic sensor 21 when the rotation detection device 1 is viewed from the direction of the rotation axis A. The magnetic sensor 23 is arranged side by side around the rotation axis A so that the magnetic sensor 23 is located on the other adjacent side of the magnetic sensor 21, and one end of the magnetic sensor 21 and one end of the magnetic sensor 22 overlap each other so that the magnetic sensor 21 The other end and one end of the magnetic sensor 23 overlap each other. By arranging the magnetic sensors 21 to 23 in this way, it is possible to increase the degree of aggregation of the arrangement of the magnetic sensors 21 to 23 while ensuring sufficient detection accuracy of the rotation of the shaft 62. That is, in order to ensure sufficient detection accuracy of the rotation of the shaft 62, it is necessary to arrange the magnetic sensors 21 to 23 at different positions in the rotation direction of the shaft 62. In the rotation detection device 1 of the present embodiment, the magnetic sensors 21 to 23 are arranged at different positions in the rotation direction of the shaft 62, the ends of the adjacent magnetic sensors 21 and 22 overlap each other, and the adjacent magnetic sensors 21. Since the ends of the 23 are overlapped with each other, the magnetic sensor 21 and the magnetic sensor 22 are brought close to each other and the magnetic sensor 21 and the magnetic sensor 23 are brought close to each other within a range in which sufficient detection accuracy of the rotation of the shaft 62 can be ensured. Can be brought close to each other, and the degree of aggregation of the arrangement of the magnetic sensors 21 to 23 can be increased.

Further, according to the rotation detection device 1 of the present embodiment, when the rotation detection device 1 is viewed from the direction of the rotation axis A, two yoke pairs adjacent to each other in the rotation direction of the shaft 62 among the yoke pairs 31 to 33 Since the yoke pairs 31 to 33 are partially overlapped with each other, the yoke pairs 31 to 33 can be centrally arranged in a part of the substrate 41, and the rotation detection device 1 including the yoke pairs 31 to 33 on the front surface 41A and the back surface 41B of the substrate 41. The areas of the regions R1 and R3 used for arranging the components can be reduced.

Further, according to the rotation detection device 1 of the present embodiment, since the magnetic sensors 21 to 23 and the yoke pairs 31 to 33 are separately arranged on the front surface 41A and the back surface 41B of one substrate 41, the magnetic sensors 21 to 23 are arranged. The dimensions of the rotation detection device 1 in the direction of the rotation axis A can be reduced as compared with the case where the yoke pairs 31 to 33 are arranged separately on a plurality of substrates.

Further, according to the rotation detection device 1 of the present embodiment, a large bulk Hausen element is used as the magnetic wire of each of the magnetic sensors 21 to 23, so that the rotation detection device of the shaft 62 with high accuracy of detecting the rotation of the shaft 62 is a non-power supply rotation detection device. Can be easily realized.

In the above embodiment, the magnetic sensors 21 to 23 and the yoke pairs 31 to 33 are separately arranged on the front surface 41A and the back surface 41B of one substrate 41, but the rotation detection of another embodiment of the present invention shown in FIG. Like the device 81, the magnetic sensors 21 to 23 and the yoke pairs 31 to 33 may be arranged separately on the two substrates 91 and 92. In the rotation detection device 81, the two substrates 91 and 92 are arranged on two planes intersecting the rotation axis A at different positions in the direction of the rotation axis A. Further, these substrates 91 and 92 are arranged around the shaft 62, respectively, and the substrate 91 is farther from the housing 63 of the motor 61 than the substrate 92. Further, the substrates 91 and 92 are formed in a disk shape having a through hole in the center, respectively, like the substrate 41 of the rotation detection device 1, and are fixed to the housing 63 of the motor 61 via a support bracket, for example. ing. Further, the magnetic sensor 21 and the yoke pair 31 are arranged on the back surface 91B of the substrate 91, and the two magnetic sensors 22, 23 and the two yoke pairs 32, 33 are arranged on the front surface 92A of the substrate 92. The positional relationship between the magnetic sensors 21 to 23 and the yoke pairs 31 to 33 when the rotation detection device 81 is viewed from the direction of the rotation axis A, and the overlapping mode of these components are such that the rotation detection device 1 is rotated. It is the same as the positional relationship between the magnetic sensors 21 to 23 and the yoke pairs 31 to 33 when viewed from the direction A, and the aspect of overlapping of these components.

Further, in the above embodiment, the magnetic sensor 21 and the magnetic sensor 22 are arranged on the front surface 41A and the back surface 41B of the substrate 41 so as to partially overlap each other when the rotation detection device 1 is viewed from the direction of the rotation axis A. Further, the magnetic sensor 21 and the magnetic sensor 23 are arranged on the front surface 41A and the back surface 41B of the substrate 41 so as to partially overlap each other when the rotation detection device 1 is viewed from the direction of the rotation axis A. However, the magnetic sensor 21 and the magnetic sensor 22 do not have to overlap each other, and when the rotation detection device 1 is viewed from the direction of the rotation axis A, the magnetic sensor 21 and the magnetic sensor 22 are placed on the same surface of the substrate 41. They may be arranged on the front surface 41A and the back surface 41B of the substrate 41 so as to be close to each other to the extent that they are difficult to arrange. Further, the magnetic sensor 21 and the magnetic sensor 23 do not have to overlap each other, and when the rotation detection device 1 is viewed from the direction of the rotation axis A, the magnetic sensor 21 and the magnetic sensor 23 are placed on the same surface of the substrate 41. They may be arranged on the front surface 41A and the back surface 41B of the substrate 41 so as to be close to each other to the extent that they are difficult to arrange. Placing the two magnetic sensors so close to each other that it is difficult to place them on the same surface of the substrate 41 means, for example, a portion required for mounting the two magnetic sensors on the substrate. And regions (areas for soldering each magnetic sensor to the board, etc.) are arranged so that they interfere with each other, and the regions required for wiring the two magnetic sensors to each magnetic sensor interfere with each other. Arrange them so that they are as close as possible.

Further, in the above embodiment, the rotation detection device 1 having two pairs of magnets 11 to 14 and three magnetic sensors 21 to 23 is given as an example, but the number of magnets and the number of magnetic sensors are not limited to this. The number of magnets in the rotation detection device of the present invention may be one pair or three or more pairs. Further, the number of magnetic sensors may be two or four or more. Further, the distance between the magnets 11 to 14 is not limited to 90 degrees, and the distance between the magnetic sensors 21 to 23 is not limited to 60 degrees.

Further, in the above embodiment, the magnetic sensors 21 to 23 are arranged so that the plane including the axis of the magnetic wire 25 is orthogonal to the rotation axis A, and the substrate 41 is arranged on the plane orthogonal to the rotation axis A. .. However, the magnetic sensors 21 to 23 are arranged so that the plane including the axis of the magnetic wire 25 intersects the rotation axis A at an angle of about 45 degrees to about 135 degrees, and the substrate 41 is arranged with the rotation axis A from about 45 degrees to about. They may be arranged so as to intersect at an angle of 135 degrees.

Further, in the above embodiment, the magnetic sensor 21 and the yoke pair 31 are arranged on the front surface 41A of the substrate 41, and the magnetic sensors 22, 23 and the yoke pairs 32, 33 are arranged on the back surface 41B of the substrate 41. The yoke pairs 31 may be arranged on the back surface 41B of the substrate 41, and the magnetic sensors 22 and 23 and the yoke pairs 32 and 33 may be arranged on the front surface 41A of the substrate 41.

Further, in the above embodiment, the optical encoder 51 having a reflective chord wheel 52 having a reflective portion 54 and a non-reflective portion 55 has been given as an example, but the optical having a transmissive cord wheel 52 having a slit is provided as an example. The formula encoder 51 may be used. In this case, the light emitting element 57 and the light receiving element 58 are arranged so as to face each other with the chord wheel 52 interposed therebetween.

Further, the present invention can be appropriately modified within a range not contrary to the gist or idea of the invention that can be read from the claims and the entire specification, and the rotation detection device accompanied by such a modification is also a technical idea of the present invention. include.

1,81 Rotation detector 11-14 Magnet (magnetic field forming part)
21-23 Magnetic sensor (magnetic field detector)
25 Magnetic wire 26 Coil 31-33 Yoke pair (magnetic field control unit)
35 York pieces 41, 91, 92 Substrate 41A, 92A Front surface 41B, 91B Back surface 61 Motor (detected device)
62 Shaft (rotating body)

Claims (8)

A rotation detection device that detects the rotation of a rotating body.
At least a pair of magnetic field forming portions that form magnetic fields having different directions and move on an orbit around the rotation axis of the rotating body as the rotating body rotates.
A plurality of magnetic field detection units that are arranged around the rotation axis so as not to move with the rotation of the rotating body, have a magnetic wire, and detect a magnetic field formed by at least one pair of magnetic field forming units. Prepare,
The plurality of magnetic field detection units are arranged at different positions in the rotation direction of the rotating body so that the extension direction of the magnetic wire is non-parallel to the rotation axis, and at positions different from each other in the direction of the rotation axis. A rotation detection device characterized in that it is divided and arranged on two or more planes intersecting with the rotation axis. The first aspect of the present invention, wherein when viewed from the direction of the rotation axis, two magnetic field detection units adjacent to each other in the rotation direction of the rotating body partially overlap each other among the plurality of magnetic field detection units. Rotation detector. When viewed from the direction of the rotation axis, the magnetic wire rods of two magnetic field detection units adjacent to each other in the rotation direction of the rotating body of the plurality of magnetic field detection units partially overlap each other. Item 2. The rotation detection device according to Item 1 or 2. A plurality of magnetic field control units for controlling the direction of the magnetic field formed by each magnetic field forming unit are provided.
The plurality of magnetic field control units are separately arranged on the two or more planes so as to correspond to the plurality of magnetic field detection units, and are respectively arranged between the plurality of magnetic field detection units and the orbits.
Claims 1 to 3 are characterized in that, when viewed from the direction of the rotation axis, two magnetic field control units adjacent to each other in the rotation direction of the rotating body of the plurality of magnetic field control units partially overlap each other. The rotation detection device according to any one of. The plurality of magnetic field detection units include a first magnetic field detection unit, a second magnetic field detection unit, and a third magnetic field detection unit.
The first magnetic field detection unit is arranged on the first plane of the first plane and the second plane that intersect with the rotation axis at different positions in the direction of the rotation axis.
The second magnetic field detection unit and the third magnetic field detection unit are arranged on the second plane.
When viewed from the direction of the rotation axis, the first magnetic field detection unit, the second magnetic field detection unit, and the third magnetic field detection unit are located next to one of the first magnetic field detection units. The second magnetic field detection unit is located, and the third magnetic field detection unit is arranged side by side around the rotation axis so that the third magnetic field detection unit is located on the other side of the first magnetic field detection unit. One end of the detection unit and one end of the second magnetic field detection unit overlap each other, and the other end of the first magnetic field detection unit and one end of the third magnetic field detection unit overlap each other. The rotation detection device according to any one of claims 1 to 4. The rotation detection device according to any one of claims 1 to 5, wherein the plurality of magnetic field detection units are separately arranged on the front surface and the back surface of a substrate arranged on a plane intersecting the rotation axis. .. The device to be detected provided with the rotating body is provided with an optical encoder that detects the rotation of the rotating body.
The optical encoder is arranged with an encoding plate that rotates with the rotation of the rotating body to generate detection light and does not move with the rotation of the rotating body, and is an optical detection unit that detects the detection light. With and
When viewed from the direction of the rotation axis, the substrate is divided into two regions, the plurality of magnetic field detection units are arranged in one of the two regions of the substrate, and the light detection unit is arranged. The rotation detection device according to claim 6, wherein the rotation detection device is arranged in the other region of the two regions of the substrate. The rotation detection device according to any one of claims 1 to 7, wherein the magnetic wire is a large bulk Hausen element.

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