Magnetic detection device and rotation detection device

Abstract

The present invention relates to a magnetic detection device. Even when three magnetic sensors are intensively mounted on a single substrate, the distances between the magnetic wire materials and the axis of the rotation axis are made equal to each other, thereby improving the accuracy of signal processing for identifying the rotation of the rotation axis. The magnetic detection unit (30) of the rotation detection device includes three magnetic sensors (31 to 33) and a substrate (45) on which these magnetic sensors are mounted. Each magnetic sensor includes a magnetic wire material (34) that generates the large Barkhausen effect, a coil (35), and a bobbin (36). Each magnetic sensor is arranged on the substrate such that the elongation direction of the magnetic wire material is parallel to the substrate (45). The magnetic detection unit is arranged on the outer peripheral side of the track of the magnetic field forming unit such that the elongation direction of the magnetic wire material is parallel to the axial direction of the rotation axis (3). In each magnetic sensor, the position of the magnetic wire material arrangement portion (38) in the bobbin is set such that the distances between the magnetic wire materials of the three magnetic sensors and the rotation axis are equal to each other.

Description

Technical Field

[0001] The present invention relates to a magnetic detection device and a rotation detection device for detecting the rotation of a rotating shaft of a rotating device such as an electric motor using magnetic detection. Background Art

[0002] For example, as a device for detecting the rotation of a rotating shaft of a rotating device such as an electric motor, a rotation detection device using a magnetic wire that generates the large Barkhausen effect is known. An example of such a rotation detection device is described in Patent Document 1 below.

[0003] The rotation detection device described in Patent Document 1 is as shown in FIGS. Figure 1 and Figure 2 of that document, and includes four magnetic field forming portions and three magnetic sensors.

[0004] Permanent magnets are used as the respective magnetic field forming portions. The four magnetic field forming portions are arranged around the rotating shaft at 90-degree intervals. In addition, the four magnetic field forming portions are arranged such that the positions of the magnetic poles of adjacent two magnetic field forming portions are opposite to each other. That is, the magnetic field forming portions that form a magnetic field in one direction of the axial direction of the rotating shaft and the magnetic field forming portions that form a magnetic field in the other direction of the axial direction of the rotating shaft are alternately arranged around the rotating shaft at 90-degree intervals. In addition, each magnetic field forming portion is fixed to the outer peripheral portion of the rotating shaft and moves around the rotating shaft as the rotating shaft rotates.

[0005] On the other hand, each magnetic sensor is formed by disposing a coil around a magnetic wire that generates the large Barkhausen effect. Specifically, each magnetic sensor has a cylindrical bobbin. A space extending in the axial direction of the bobbin is formed inside the bobbin, and the magnetic wire is accommodated in this space. In addition, a wire forming a coil is wound around the outer periphery of the middle portion of the bobbin. The three magnetic sensors are arranged on the outer peripheral side of the orbits of the four magnetic field forming portions at 120-degree intervals. In addition, each magnetic sensor is arranged such that the extending direction of the magnetic wire is parallel to the axial direction of the rotating shaft. In addition, each magnetic sensor is fixed to the housing of the rotation detection device or the like so as not to move as the rotating shaft rotates.

[0006] If the rotating shaft rotates, the four magnetic field forming parts move around the rotating shaft and pass near the three magnetic sensors in sequence. Here, if we focus on one of the three magnetic sensors, when the rotating shaft rotates, the magnetic field forming part that forms the magnetic field in one direction along the axial direction of the rotating shaft and the magnetic field forming part that forms the magnetic field in the other direction along the axial direction of the rotating shaft pass near this one magnetic sensor alternately. As a result, the direction of the magnetic field of the magnetic wire acting on this one magnetic sensor changes as the rotating shaft rotates. The magnetic wire has the property that if the direction of the magnetic field acting on it changes, its magnetization direction reverses sharply, that is, the property of generating the large Barkhausen effect. In addition, if the magnetization direction of the magnetic wire reverses sharply, a pulsed current flows in the coil through electromagnetic induction. Therefore, when the rotating shaft rotates, a pulsed signal is output from the coil of this one magnetic sensor. Based on the same principle, when the rotating shaft rotates, pulsed signals are also output from the coils of the other two magnetic sensors.

[0007] The four magnetic field forming parts are arranged at 90-degree intervals, and the three magnetic sensors are arranged at 120-degree intervals, so two or more magnetic field forming parts do not pass near two or more magnetic sensors simultaneously. Therefore, during the rotation of the rotating shaft, pulsed signals are output from the three magnetic sensors at different times respectively. Based on these pulsed signals, the rotation of the rotating shaft can be detected, for example, the rotational speed or the rotation angle of the rotating shaft can be detected.

[0008] In addition, according to the rotation detection device using the magnetic wire that generates the large Barkhausen effect, a pulsed signal for detecting the rotation of the rotating shaft can be formed through the large Barkhausen effect and electromagnetic induction. Therefore, the rotation of the rotating shaft can be detected without a power source.

[0009] Furthermore, in order to achieve high-precision rotation detection by the rotation detection device using the magnetic wire that generates the large Barkhausen effect, it is preferable that the number of magnetic sensors is three or more (refer to the above Patent Document 1). On the other hand, the number of magnetic field forming parts is not limited to four and can also be two. By using four magnetic field forming parts and three magnetic sensors, the rotation of the rotating shaft can be detected with high precision in units of 30 degrees. In addition, by using two magnetic field forming parts and three magnetic sensors, the rotation of the rotating shaft can be detected with high precision in units of 60 degrees. Furthermore, the number of magnetic field forming parts can also be set to six or more. However, in this case, it is necessary to adjust the intervals between the magnetic field forming parts and the intervals between the magnetic sensors so that two or more magnetic field forming parts do not pass near two or more magnetic sensors simultaneously.

[0010] Patent Document 1: International Publication No. 2016 / 002437

[0011] When assembling the rotation detection device as described above in a rotating device such as an electric motor, each magnetic field forming portion is mounted on the outer peripheral portion of a portion protruding from the main body of the rotating device on the rotating shaft. In addition, each magnetic sensor is mounted on the main body of the rotating device via a support member or the like, and is disposed on the outer peripheral side of the orbit of each magnetic field forming portion.

[0012] However, in the case where the rotating device is small, the space for arranging the magnetic field forming portion and the magnetic sensor becomes small. Therefore, when assembling the rotation detection device in the rotating device, various engineering studies are required. For example, it is desired to reduce the size of each magnetic field forming portion and each magnetic sensor. In addition, for example, it is desired to directly mount the magnet constituting each magnetic field forming portion on the outer peripheral portion of the rotating shaft or the like to reduce the diameter of the orbit of the magnetic field forming portion. In addition, it is desired to dispose each magnetic sensor close to the orbit of the magnetic field forming portion. In addition, for example, it is desired to arrange the magnetic sensors at intervals of 30 degrees or the like to reduce the interval between the magnetic sensors. Furthermore, it is desired to centrally mount the three magnetic sensors included in the rotation detection device on one substrate, thereby making the support structure of each magnetic sensor compact.

[0013] Here, when mounting three magnetic sensors on one substrate, there is a problem as follows.

[0014] Each magnetic field forming portion is fixed to the outer peripheral portion of the rotating shaft and moves along a circular orbit centered on the axis of the rotating shaft as the rotating shaft rotates. In addition, the three magnetic sensors are arranged on the outer peripheral side of the circular orbit of the magnetic field forming portion such that the distances from the magnetic wire materials of the magnetic sensors to the axis of the rotating shaft are equal to each other. According to this configuration, since the distances between the circular orbit of the magnetic field forming portion and the magnetic wire materials of the respective magnetic sensors are equal, the magnetic fields formed by each magnetic field forming portion act on the magnetic wire materials of the respective magnetic sensors equally. As a result, when the magnetic field forming portion passes near the magnetic sensor, the timing at which a pulse signal is output from the coil of the magnetic sensor is the same for each magnetic sensor. That is, in the case of the above-described rotation detection device in which four magnetic field forming portions are arranged around the rotating shaft at intervals of 90 degrees and three magnetic sensors are arranged on the outer peripheral side of the orbits of the four magnetic field forming portions at intervals of 120 degrees, when the rotating shaft rotates at a constant speed in one direction, the timings of the pulse signals output from the three magnetic sensors become equal intervals. In addition, the magnetic fields formed by each magnetic field forming portion act equally on the magnetic wire materials of the respective magnetic sensors. As a result, the peaks of the pulse signals output from the coils of the magnetic sensors are the same for each magnetic sensor. In this way, when the magnetic field forming portion passes near the magnetic sensor, the timing at which a pulse signal is output from the coil of the magnetic sensor is the same for each magnetic sensor, and the peaks of the pulse signals output from the coils of the magnetic sensors are the same for each magnetic sensor. Thus, by using these pulse signals, the accuracy of signal processing for identifying the rotation of the rotating shaft can be improved.

[0015] However, when three magnetic sensors are mounted on a substrate and arranged on the flat surface of the substrate, the three magnetic wire materials of the three magnetic sensors are arranged on the same plane. As a result, there is a problem that the distances between the magnetic wire materials and the axis of the rotation axis cannot be made equal to each other in the three magnetic sensors.

[0016] For example, when three magnetic sensors are mounted on a substrate, as a result, when the distance between the magnetic wire material of one magnetic sensor and the axis of the rotation axis in the three magnetic sensors is different from the distance between the magnetic wire material of another magnetic sensor and the axis of the rotation axis, when the magnetic field forming portion passes near the magnetic sensor, the timing of the pulse signal output from the coil of the magnetic sensor is different between the two magnetic sensors, or the peak of the pulse signal output from the coil of the magnetic sensor is different between the two magnetic sensors. When such a situation occurs, there is a concern that the accuracy of the above signal processing may be reduced. Summary of the Invention

[0017] The present invention is completed in view of the above problems, and an object of the present invention is to provide a magnetic detection device and a rotation detection device that can make the distances between the magnetic wire materials and the axis of the rotation axis equal to each other in at least three magnetic sensors even when the at least three magnetic sensors are intensively mounted on a substrate, and can improve the accuracy of signal processing for identifying the rotation of the rotation axis.

[0018] To solve the above problems, the magnetic detection device of the present invention is a magnetic detection device for detecting each of the magnetic fields in a rotation detection device that has at least two magnetic field forming portions that move around the rotation axis as the rotation axis rotates and respectively form a magnetic field in one direction and the other direction of the axial direction of the rotation axis, and detects the rotation of the rotation axis, and includes: at least three magnetic sensors; and a substrate having a mounting surface for mounting the three magnetic sensors. Each of the magnetic sensors includes: a magnetic wire material that generates the large Barkhausen effect; a coil provided on the outer peripheral side of the magnetic wire material; and a bobbin having a wire winding portion formed in a columnar shape and winding the wire of the coil, and a magnetic wire material arrangement portion that is a space extending in the axial direction within the wire winding portion and arranges the magnetic wire material. The three magnetic sensors are arranged on the mounting surface such that the extending direction of the magnetic wire material of each of them is parallel to the mounting surface, and the three magnetic sensors and the substrate are arranged on the outer peripheral side of the tracks of the two magnetic field forming portions such that the extending direction of the magnetic wire material of each of the magnetic sensors is parallel to the axial direction of the rotation axis. In each of the three magnetic sensors, the position of the magnetic wire material arrangement portion of the bobbin is set such that the distances between the magnetic wire materials of the three magnetic sensors and the rotation axis are equal to each other.

[0019] In addition, in the magnetic detection device of the present invention described above, it is also possible to make the distance between the magnetic wire arrangement portion of the bobbin of the middle magnetic sensor among the three magnetic sensors and the placement surface smaller than the distances between the magnetic wire arrangement portions of the bobbins of the magnetic sensors at both ends among the three magnetic sensors and the placement surface.

[0020] In addition, in the magnetic detection device of the present invention described above, it is also possible to provide that in the bobbin of each magnetic sensor, the magnetic wire arrangement portion is formed from the circumferential surface of the wire winding portion toward the inside of the wire winding portion, and is a groove extending along the axial direction of the wire winding portion. The groove formed in the wire winding portion of the bobbin of the middle magnetic sensor among the three magnetic sensors is deeper than the grooves formed in the wire winding portions of the bobbins of the magnetic sensors at both ends among the three magnetic sensors.

[0021] In addition, in the magnetic detection device of the present invention described above, it is also possible to set the shape of the cross-section of the coil of each magnetic sensor to be a substantially elliptical shape with the major axis extending in a direction orthogonal to the placement surface.

[0022] In addition, in the magnetic detection device of the present invention described above, it is also possible to set the shape of the cross-section of the wire winding portion of the bobbin of each magnetic sensor to be a substantially elliptical shape with the major axis extending in a direction orthogonal to the placement surface.

[0023] In order to solve the above problems, a rotation detection device of the present invention is a rotation detection device for detecting the rotation of a rotation axis, and includes: at least two magnetic field forming portions that move around the rotation axis as the rotation axis rotates, and respectively form magnetic fields in one direction and the other direction of the axial direction of the rotation axis; and a magnetic detection portion that does not move as the rotation axis rotates and detects the magnetic fields formed by the two magnetic field forming portions. The magnetic detection portion includes: at least three magnetic sensors; and a substrate having a placement surface for placing the three magnetic sensors. Each magnetic sensor includes: a magnetic wire that generates a large Barkhausen effect; a coil provided on the outer peripheral side of the magnetic wire; and a bobbin having a wire winding portion with an outer shape formed in a columnar shape and winding the wire of the coil, and a magnetic wire arrangement portion that is a space extending along the axial direction in the wire winding portion and arranges the magnetic wire. The three magnetic sensors are arranged on the placement surface such that the extending directions of the magnetic wires of each are parallel to the placement surface, and the magnetic detection portion is arranged on the outer peripheral side of the orbits of the two magnetic field forming portions such that the extending directions of the magnetic wires of each magnetic sensor are parallel to the axial direction of the rotation axis. In each magnetic sensor, the position of the magnetic wire arrangement portion of the bobbin is set such that the distances between the magnetic wires of the three magnetic sensors and the rotation axis are respectively equal to each other.

[0024] According to the present invention, even when at least three magnetic sensors are intensively mounted on one substrate, it is possible to make the distances between the magnetic wire materials and the axis of the rotation axis equal to each other among these magnetic sensors, and it is possible to improve the accuracy of signal processing for identifying the rotation of the rotation axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a perspective view of a rotation detection device and an electric motor according to an embodiment of the present invention in a state where the housing is removed.

[0026] Figure 2 It is a perspective view of a rotation detection device and an electric motor according to an embodiment of the present invention in a state where the housing is installed.

[0027] Figure 3 It is a perspective view of a bracket of a rotation detection device according to an embodiment of the present invention.

[0028] Figure 4 It is an explanatory view of an installation structure of a magnetic detection unit according to an embodiment of the present invention on a bracket.

[0029] Figure 5 It is a perspective view of an arrangement of a magnetic field forming unit according to an embodiment of the present invention.

[0030] Figure 6 It is an explanatory view of a magnetic detection unit according to an embodiment of the present invention.

[0031] Figure 7 It is a front view of a magnetic detection unit according to an embodiment of the present invention.

[0032] Figure 8 It is a top view of a magnetic detection unit according to an embodiment of the present invention.

[0033] Figure 9 It is shown from Figure 7 above in Figure 7 a cross-sectional view of the magnetic detection unit taken along the cutting line IX-IX.

[0034] Figure 10 It is a rear view of a magnetic detection unit according to an embodiment of the present invention.

[0035] Figure 11 It is shown from Figure 1 above in Figure 1 a cross-sectional view of the rotation axis and the magnetic detection unit taken along the cutting line XI-XI and other states.

[0036] Figure 12 It is shown from Figure 2 above in Figure 2Cross-sectional view of the rotation detection device cut along the cutting line XII-XII in [device name] and the state of the housing

[0037] Figure 13 It is an explanatory diagram showing the operation of the rotation detection device according to an embodiment of the present invention.

[0038] Explanation of reference numerals

[0039] 1... Electric motor (rotating device); 2... Main body; 3... Rotating shaft; 4... Protrusion; 11... Rotation detection device; 21-24... Magnetic field forming parts; 30... Magnetic detection part; 31-33... Magnetic sensors; 34... Magnetic wire; 35... Coil; 36... Bobbin; 37... Wire winding part; 38... Magnetic wire arrangement part; 41... First connecting member; 42... Second connecting member; 45... Substrate; 46... Mounting surface; 51... Circuit; 71... Bracket; 83... Housing; 84... Front wall plate; 85... Rear wall plate; 86... Left wall plate; 87... Right wall plate. Detailed implementation mode

[0040] (Rotation detection device)

[0041] Figure 1 The rotation detection device 11 according to an embodiment of the present invention in a state where the housing is removed and the electric motor 1 assembled with the rotation detection device 11 are shown. The electric motor 1 is a specific example of a rotating device. As Figure 1 shown, the electric motor 1 includes a main body 2 and a rotating shaft 3 rotatably provided on the main body 2. When the electric motor 1 operates, the rotating shaft 3 rotates relative to the main body 2. In addition, one end side of the rotating shaft 3 protrudes from the main body 2. Hereinafter, the one end side portion of the rotating shaft 3 protruding from the main body 2 will be referred to as a protrusion 4.

[0042] In addition, in the description of the directions of up (Ud), down (Dd), front (Fd), rear (Bd), left (Ld), and right (Rd) in the description of the embodiment, as a principle, based on Figure 1 the arrow drawn in the lower right in [reference drawing]. In addition, in the description of the embodiment, as Figure 1 shown, the electric motor 1 is arranged so that it passes through the whole and one end side of the rotating shaft 3 faces upward.

[0043] The rotation detection device 11 is a magnetic rotation detection device using a magnetic wire that generates the large Barkhausen effect. The rotation detection device 11 is provided around the protrusion 4 of the rotating shaft 3 and is supported on the main body 2 of the electric motor 1 by a bracket 71.

[0044] The rotation detection device 11 detects the rotation of the rotation shaft 3 of the electric motor 1. Specifically, when the power supplies of the electric motor 1 and the rotation detection device 11 are turned on, the rotation detection device 11 performs rotation detection of the rotation shaft 3 and outputs the detection result to, for example, the drive control circuit of the electric motor 1. The drive control circuit of the electric motor 1 controls the drive of the electric motor based on the detection result output from the rotation detection device 11.

[0045] In addition, the rotation detection device 11 can operate without power supply (refer to the above-mentioned Patent Document 1). During the period when the power supplies of the electric motor 1 and the rotation detection device 11 are cut off, when an external force is applied to the rotation shaft 3 and the rotation shaft 3 rotates, the rotation detection device 11 detects this rotation and stores the detection result. Then, when the power supplies of the electric motor 1 and the rotation detection device 11 are turned on, the rotation detection device 11 outputs the detection result stored during the period when the power supplies of the electric motor 1 and the rotation detection device 11 are cut off to the drive control circuit of the electric motor 1. Thereby, when the drive control of the electric motor 1 is restarted, the drive control circuit of the electric motor 1 can identify the rotation amount of the rotation shaft 3 during the period when the power supplies of the electric motor 1 and the rotation detection device 11 are cut off.

[0046] Figure 2 The rotation detection device 11 and the electric motor 1 in a state where the housing is installed are shown. The rotation detection device 11 includes a housing 83. The housing 83 is as Figure 2 shown, and has a front wall plate 84 located in front of the protruding portion 4 of the rotation shaft 3, a rear wall plate 85 located behind the protruding portion 4 (refer to Figure 12 ), a left wall plate 86 located to the left of the protruding portion 4, a right wall plate 87 located to the right of the protruding portion 4 (refer to Figure 12 ), and an upper wall plate 88 located above the protruding portion 4. The housing 83 is formed into a rectangular tube shape with the upper side closed by the front wall plate 84, the rear wall plate 85, the left wall plate 86, the right wall plate 87, and the upper wall plate 88, covering the periphery of the protruding portion 4 of the rotation shaft 3, the annular magnets 25 and 26, and the magnetic detection portion 30. In addition, the housing 83 is fixed to the bracket 71. In addition, the left-right dimension of each of the front wall plate 84 and the rear wall plate 85 is, for example, about 20 mm, and the front-rear dimension of each of the left wall plate 86 and the right wall plate 87 is, for example, about 15 mm.

[0047] Figure 3 The bracket 71 is shown. As Figure 3As shown in the figure, the bracket 71 includes a lower base 72 fixed to the main body 2 of the electric motor 1, an upper base 75 provided above the lower base 72, and wall portions 77, 78 for supporting the upper base 75 above the lower base 72. The lower base 72 is generally formed in a rectangular parallelepiped shape and has a rectangular base surface 73 in a top view. In addition, a shaft insertion through-hole 74 for passing the protruding portion 4 of the rotary shaft 3 is provided in the lower base 72, and the shaft insertion through-hole 74 opens in the base surface 73. In addition, the upper base 75 is also generally formed in a rectangular parallelepiped shape and is provided with a shaft insertion through-hole 82 for passing the protruding portion 4 of the rotary shaft 3. The protruding portion 4 of the rotary shaft 3 passes through the shaft insertion through-hole 74 of the lower base 72 and the shaft insertion through-hole 82 of the upper base 75, and thus extends upward through the bracket 71. In addition, since the diameters of the shaft insertion through-hole 74 of the lower base 72 and the shaft insertion through-hole 82 of the upper base 75 are each set to be larger than the diameter of the protruding portion 4 of the rotary shaft 3, the bracket 71 does not hinder the rotation of the rotary shaft 3. In addition, the distance from the base surface 73 of the lower base 72 to the upper surface 76 of the upper base 75 is, for example, approximately 20 mm.

[0048] Figure 4 (A) of shows the state of observing the bracket 71 from the right side. As Figure 4 shown in (A) of, two mounting portions 79, 80 for mounting the magnetic detection portion 30 of the rotation detection device 11 are provided on the bracket 71. One mounting portion 79 is provided at the right rear portion of the lower base 72, and the other mounting portion 80 is provided at the right front portion of the upper base 75. Threaded holes 81 are respectively provided in the mounting portions 79, 80. Figure 4 (B) of shows Figure 4 the state in which the magnetic detection portion 30 is mounted on the bracket 71 shown in (A) of. As Figure 4 shown in (B) of, the magnetic detection portion 30 is mounted on the mounting portions 79, 80 of the bracket 71 using screws 56.

[0049] The rotation detection device 11 includes: four magnetic field forming portions that move around the rotary shaft 3 as the rotary shaft 3 rotates and respectively form magnetic fields in one direction and the other direction in the axial direction of the rotary shaft 3; and a magnetic detection portion 30 that does not move as the rotary shaft 3 rotates and detects the magnetic fields formed by the four magnetic field forming portions. As Figure 1 shown in the figure, the four magnetic field forming portions are formed by two annular magnets 25, 26 mounted on the outer peripheral portion of the protruding portion 4 of the rotary shaft 3. In addition, the magnetic detection portion 30 includes three magnetic sensors 31 to 33 and a substrate 45, and is mounted on the mounting portions 79, 80 of the bracket 71.

[0050] (Magnetic field forming portion)

[0051] Figure 5 shows the four magnetic field forming portions 21 to 24 of the rotation detection device 11. AsFigure 5 As shown, two annular magnets 25 and 26 are mounted on the outer periphery of the protrusion 4 of the rotating shaft 3. The annular magnet 25 is mounted on the upper portion of the protrusion 4 (the portion on one axial side of the rotating shaft 3), and the annular magnet 26 is mounted on the lower portion of the protrusion 4 (the portion on the other axial side of the rotating shaft 3). Each annular magnet 25 and 26 is a permanent magnet formed in an annular shape. Each annular magnet 25 and 26 is fixed to the outer periphery of the protrusion 4 by, for example, an adhesive. Each annular magnet 25 and 26 rotates together with the rotating shaft 3. In other words, when the rotating shaft 3 rotates, each annular magnet 25 and 26 moves around the rotating shaft 3 in a manner that describes a circle centered on the axis X of the rotating shaft 3.

[0052] Each of the annular magnets 25 and 26 is magnetized so that a plurality of magnetic poles are arranged on its outer circumference. Specifically, four magnetic poles 25A to 25D are arranged at 90-degree intervals on the outer circumference of the annular magnet 25. In addition, four magnetic poles 26A to 26D are arranged at 90-degree intervals on the outer circumference of the annular magnet 26. In addition, the magnetic poles 25A and 26A are arranged so that their circumferential positions coincide with each other and they are adjacent in the vertical direction (axial direction of the rotating shaft 3). Similarly, the circumferential positions of the magnetic poles 25B and 26B coincide with each other, the circumferential positions of the magnetic poles 25C and 26C coincide with each other, and the circumferential positions of the magnetic poles 25D and 26D coincide with each other.

[0053] In annular magnet 25, magnetic poles 25A to 25D are arranged so that circumferentially adjacent magnetic poles are mutually different. In annular magnet 26, magnetic poles 26A to 26D are arranged so that circumferentially adjacent magnetic poles are mutually different. Furthermore, annular magnets 25 and 26 are arranged so that vertically adjacent magnetic poles are mutually different. For example, the four magnetic poles 25A, 25C, 26B, and 26D are each north pole. Furthermore, the four magnetic poles 25B, 25D, 26A, and 26C are each south pole.

[0054] Among the four magnetic field forming portions 21 to 24, the first magnetic field forming portion 21 is formed by the magnetic poles 25A and 26A. The first magnetic field forming portion 21 forms a magnetic field in the downward direction (a magnetic field in one direction along the axial direction of the rotating shaft 3). The second magnetic field forming portion 22 is formed by the magnetic poles 25B and 26B. The second magnetic field forming portion 22 forms a magnetic field in the upward direction (a magnetic field in the other direction along the axial direction of the rotating shaft 3). The third magnetic field forming portion 23 is formed by the magnetic poles 25C and 26C. The third magnetic field forming portion 23 forms a magnetic field in the downward direction (a magnetic field in one direction along the axial direction of the rotating shaft 3). The fourth magnetic field forming portion 24 is formed by the magnetic poles 25D and 26D. The fourth magnetic field forming portion 24 forms a magnetic field in the upward direction (a magnetic field in the other direction along the axial direction of the rotating shaft 3). In this way, the four magnetic field forming portions 21 to 24 are formed on the outer peripheral portion of the protruding portion 4 of the rotating shaft 3 by the magnetic poles 25A to 25D of the annular magnet 25 and the magnetic poles 26A to 26D of the annular magnet 26, and are arranged at intervals of 90 degrees on the outer peripheral portion of the protruding portion 4. In addition, these magnetic field forming portions 21 to 24 are arranged in such a manner that the directions of the magnetic fields formed by two adjacent magnetic field forming portions in the circumferential direction are different from each other (opposite to each other). In addition, when the rotating shaft 3 rotates, these magnetic field forming portions 21 to 24 move around the rotating shaft 3 in such a manner as to draw a circle centered on the axis X of the rotating shaft 3.

[0055] (Magnetic detection unit)

[0056] Figure 6 (A) of shows the magnetic detection unit 30. Figure 6 (B) of shows the state after disassembling the magnetic detection unit 30. Figure 7 Shows the state of observing the magnetic detection unit 30 from its front. Figure 8 Shows from Figure 7 above in Figure 7 the state of observing the magnetic detection unit 30 in Figure 9 Shows from Figure 7 above in Figure 7 the state of observing the cross-section of the magnetic detection unit 30 cut along the cutting line IX-IX in Figure 10 Shows the back of the magnetic detection unit 30. Figure 11 Shows along Figure 1 the cross-section of the rotating shaft 3 and the magnetic detection unit 30 cut along the cutting line XIXI in

[0057] As described above, the magnetic detection unit 30 includes three magnetic sensors 31 to 33 and a substrate 45. As Figure 7As shown, each of the magnetic sensors 31 to 33 includes a magnetic wire 34, a coil 35, a bobbin 36, a first connecting member 41, and a second connecting member 42. In addition, the magnetic detection unit 30 is a specific example of the magnetic detection unit of the rotation detection device described in the technical solution, and is also a specific example of a magnetic detection device.

[0058] The magnetic wire 34 is a large Barkhausen element. Specifically, the magnetic wire 34 is a linear ferromagnetic body that generates the large Barkhausen effect and has uniaxial anisotropy. The magnetic wire 34 is a component called a composite magnetic wire. The magnetic wire 34 can be formed, for example, by twisting a semi-rigid magnetic wire containing iron and cobalt. The length of the magnetic wire 34 is, for example, about 10 mm to 18 mm.

[0059] The coil 35 is provided on the outer peripheral side of the magnetic wire 34. The coil 35 is formed, for example, by winding an electric wire such as an enameled wire around the bobbin 36.

[0060] The bobbin 36 is integrally formed in a cylindrical shape from a resin material. As Figure 9 shown, the bobbin 36 has a wire winding portion 37 for winding the wire of the coil 35 and a magnetic wire arrangement portion 38 for arranging the magnetic wire 34.

[0061] The wire winding portion 37 is formed in the middle portion of the bobbin 36 in the axial direction. The wire winding portion 37 has a cylindrical outer shape. The wire of the coil 35 is wound around the outer periphery of the wire winding portion 37. In addition, in Figure 9 、 Figure 11 and Figure 12 the specific illustration of the wire of the coil 35 is omitted.

[0062] The magnetic wire arrangement portion 38 is a space that extends in the axial direction within the wire winding portion 37. Specifically, the magnetic wire arrangement portion 38 is formed from the peripheral surface of the wire winding portion 37 toward the inside of the wire winding portion 37 and is a groove that extends in the axial direction of the wire winding portion 37. As Figure 9 shown, the magnetic wire 34 is arranged within the magnetic wire arrangement portion 38. Specifically, the magnetic wire 34 is arranged on the bottom (for example, on the bottom surface of the groove) of the groove that is the magnetic wire arrangement portion 38. The magnetic wire 34 is located inside the coil 35 by being arranged within the magnetic wire arrangement portion 38. In addition, as Figure 7 shown, the upper end of the magnetic wire arrangement portion 38 extends beyond the upper end of the wire winding portion 37 and toward the upper end side of the bobbin 36, and the lower end of the magnetic wire arrangement portion 38 extends beyond the lower end of the wire winding portion 37 and toward the lower end side of the bobbin 36. In addition, the upper end of the magnetic wire 34 extends beyond the upper end of the coil 35 and toward the upper end side of the bobbin 36, and the lower end of the magnetic wire 34 extends beyond the lower end of the coil 35 and toward the lower end side of the bobbin 36.

[0063] The first connecting member 41 and the second connecting member 42 each function as a support for the end of the wire of the stop coil 35, and function as terminals for electrically connecting the coil 35 to the circuit 51 formed on the substrate 45 (refer to Figure 10 ). The first connecting member 41 and the second connecting member 42 are each formed in a rod shape from a conductive material such as metal, for example. As Figure 7 shown, the first connecting member 41 is provided at the upper end side portion of the bobbin 36, and the second connecting member 42 is provided at the lower end side portion of the bobbin 36. Further, as Figure 8 shown, one end portion of the wire of the coil 35 is wound around and fixed to one end side portion 41A (the lower end side portion in Figure 8 ) of the first connecting member 41. Further, the other end portion of the wire of the coil 35 is wound around and fixed to one end side portion 42A of the second connecting member 42. Further, the other end side portion 41B (the upper end side portion in Figure 8 ) of the first connecting member 41 is electrically connected to the circuit 51 formed on the substrate 45. The other end side portion 42B of the second connecting member 42 is also electrically connected to the circuit 51.

[0064] The substrate 45 is, for example, a printed circuit board formed of epoxy resin glass. The substrate 45 is formed, for example, in a rectangular flat plate shape with a long side of about 20 mm and a short side of about 10.5 mm. Further, as Figure 6 (B) of the figure shows, the front surface of the substrate 45 becomes a mounting surface 46 for mounting the three magnetic sensors 31 to 33. Further, screw insertion holes 47 through which the screws 56 for the mounting portions 79, 80 for mounting the magnetic detection unit 30 to the bracket 71 are passed are formed at two corner portions of the substrate 45, respectively. Further, six connecting member insertion holes 48 through which the other end side portions 41B, 42B of the first connecting member 41 and the second connecting member 42 respectively provided for the three magnetic sensors 31 to 33 pass are formed in the substrate 45.

[0065] Further, as Figure 10As shown, a circuit 51 is formed on the back surface of the substrate 45. The circuit 51 includes: an IC (integrated circuit) 52 that performs signal processing for identifying the rotation of the rotating shaft 3 based on detection signals output from the coils 35 of the three magnetic sensors 31 to 33 respectively; six connection pads 53 that electrically connect the other end portions 41B and 42B of the first connection members 41 and the second connection members 42 respectively provided in the three magnetic sensors 31 to 33; and wirings 54 for electrically connecting each connection pad 53 to the IC 52. The six connection pads 53 are arranged at positions corresponding to the six connection member insertion holes 48. Each connection member insertion hole 48 is located at the center of the connection pad 53. The other end portions 41B and 42B of the first connection member 41 and the second connection member 42 of each of the magnetic sensors 31 to 33 reach the back surface of the substrate 45 through the connection member insertion holes 48 from the mounting surface 46 of the substrate 45 and are connected to the connection pads 53 formed on the back surface of the substrate 45 by welding, for example. In addition, although the IC 52 is illustrated in Figure 4 and Figure 10 it is omitted in other figures.

[0066] As Figure 6 (A) of shows, the three magnetic sensors 31 to 33 are arranged on the mounting surface 46 such that the extending directions of their respective magnetic wires 34 are parallel to the mounting surface 46 of the substrate 45. In addition, the three magnetic sensors 31 to 33 are arranged on the mounting surface 46 such that the extending directions of the magnetic wires 34 are parallel to each other. In addition, when observing the magnetic detection unit 30 from the front, the three magnetic sensors 31 to 33 are arranged on the mounting surface 46 such that the intervals between the three magnetic wires 34 are equal. In addition, among the three magnetic sensors 31 to 33, the intervals between two adjacent magnetic sensors on the mounting surface 46 are extremely small. In addition, the bobbins 36 of the three magnetic sensors 31 to 33 are respectively arranged on the flat mounting surface 46 of the substrate 45, and the axes (the straight lines passing through the centers of the wire winding portions 37 along the axial directions) of the wire winding portions 37 of the three bobbins 36 are located in the same plane parallel to the mounting surface 46.

[0067] In addition, as Figure 1 shown, the orientation of the magnetic detection unit 30 is set such that the mounting surface 46 of the substrate 45 on which the three magnetic sensors 31 to 33 are mounted faces the protruding portion 4 of the rotating shaft 3, and the extending directions of the magnetic wires 34 of each of the magnetic sensors 31 to 33 are parallel to the axial direction of the rotating shaft 3. In addition, as Figure 11 shown, the magnetic detection unit 30 is arranged on the outer peripheral side of the protruding portion 4 of the rotating shaft 3 and on the outer peripheral side of the tracks T of the four magnetic field forming units 21 to 24. In addition, as Figure 4 (B) of shows, the magnetic detection unit 30 is fixed to the bracket 71 by mounting two corner portions of the substrate 45 to the mounting portions 79 and 80 of the bracket 71 using screws 56.

[0068] Thus, according to an embodiment of the present invention, by collectively mounting the three magnetic sensors 31 to 33 on one substrate, the rotation detection device 11 can be miniaturized. In particular, the three magnetic sensors 31 to 33 are mounted on the mounting surface 46 of one substrate 45 such that the elongation directions of the respective magnetic wires 34 are parallel to the mounting surface 46 of the substrate 45 and the elongation directions of the respective magnetic wires 34 are parallel to each other, and the substrate 45 is mounted on the bracket 71 such that the elongation directions of the magnetic wires 34 of the three magnetic sensors 31 to 33 are parallel to the axial direction of the rotation shaft 3. Therefore, the rotation detection device 11 can be housed in a small-diameter cylindrical region around the rotation shaft 3. Thus, according to the present embodiment, a rotation detection device 11 that can be assembled to a small electric motor 1 having a main body 2 with a small diameter dimension can be realized.

[0069] (Position of Magnetic Wire Arrangement Portion and Shape of Coil)

[0070] As Figure 11 shown, in each of the three magnetic sensors 31 to 33, the position of the magnetic wire arrangement portion 38 of the bobbin 36 is set such that the distances from the three magnetic wires 34 included in the three magnetic sensors 31 to 33 to the axis X of the rotation shaft 3 are equal to each other, and the three magnetic wires 34 are arranged around the axis X of the rotation shaft 3 at a predetermined interval.

[0071] Specifically, the distance b between the magnetic wire arrangement portion 38 of the bobbin 36 of the middle magnetic sensor 32 among the three magnetic sensors 31 to 33 and the mounting surface 46 of the substrate 45 is smaller than either of the distances a and c between the magnetic wire arrangement portions 38 of the bobbins 36 of the two end magnetic sensors 31 and 33 among the three magnetic sensors 31 to 33 and the mounting surface 46 of the substrate 45. More specifically, the groove serving as the magnetic wire arrangement portion 38 formed in the bobbin 36 of the middle magnetic sensor 32 is deeper than any one of the grooves serving as the magnetic wire arrangement portion 38 formed in the bobbins 36 of the two end magnetic sensors 31 and 33. As a result, the distance b between the bottom surface of the groove serving as the magnetic wire arrangement portion 38 formed in the bobbin 36 of the middle magnetic sensor 32 and the mounting surface 46 is smaller than either of the distances a and c between the bottom surfaces of the grooves serving as the magnetic wire arrangement portion 38 formed in the bobbins 36 of the two end magnetic sensors 31 and 33 and the mounting surface 46.

[0072] In addition, as the magnetic wire disposing portion 38, the depths of the grooves of the bobbin 36 of the two magnetic sensors 31 and 33 located at both ends are equal to each other. As a result, the distances a and c between the bottom surfaces of the grooves of the bobbin 36 of the magnetic wire disposing portion 38 formed in the two magnetic sensors 31 and 33 located at both ends and the mounting surface 46 (that is, the distances between the magnetic wire disposing portion 38 of the bobbin 36 of the two magnetic sensors 31 and 33 located at both ends and the mounting surface 46) are equal to each other.

[0073] By setting the positions of the magnetic wire disposing portions 38 of the three magnetic sensors 31 to 33 in this way, the distances between the three magnetic wires 34 respectively disposed in these magnetic wire disposing portions 38 and the axis X of the rotating shaft 3 are equal to each other. That is, as Figure 11 shown, these three magnetic wires 34 are located on the circumference of a circle U centered on the axis X of the rotating shaft 3. In addition, as a result, the distances between the three magnetic wires 34 and the tracks T of the magnetic field forming portions 21 to 24 are equal to each other. In addition, by setting the positions of the magnetic wire disposing portions 38 of the three magnetic sensors 31 to 33 as described above, the three magnetic wires 34 are disposed on the circumference of the circle U at a prescribed interval. In the present embodiment, the three magnetic wires 34 are disposed on the circumference of the circle U at 30-degree intervals.

[0074] In addition, as Figure 11 shown, the shape of the cross section of the wire winding portion 37 of the bobbin 36 of each of the magnetic sensors 31 to 33 is a substantially elliptical shape in which the major axis extends in a direction orthogonal to the mounting surface 46. In addition, the shape of the cross section of the coil 35 of each of the magnetic sensors 31 to 33 is a substantially elliptical shape in which the major axis extends in a direction orthogonal to the mounting surface 46.

[0075] Thus, in the rotation detection device 11 according to the embodiment of the present invention, the distance b between the magnetic wire arrangement portion 38 of the solenoid 36 of the middle magnetic sensor 32 and the mounting surface 46 of the substrate 45 is set to be smaller than either of the distances a and c between the magnetic wire arrangement portions 38 of the solenoids 36 of the two magnetic sensors 31 and 33 at both ends. Thus, the positions of the magnetic wire arrangement portions 38 in the solenoids 36 of the three magnetic sensors 31 to 33 are set, so that the three magnetic sensors 31 to 33 can be arranged on the flat mounting surface 46 of the substrate 45, and the distances between the three magnetic wires 34 respectively included in the three magnetic sensors 31 and the axis X of the rotation shaft 3 can be made to be the same. By making the distances between the three magnetic wires 34 and the axis X of the rotation shaft 3 the same, when the magnetic field forming portions 21 to 24 pass near the magnetic sensors among the three magnetic sensors 31 to 33, the timing of outputting pulses from the coils 35 of the magnetic sensors can be made to be the same, or the heights of the pulses output from the coils 35 of the respective magnetic sensors 31 to 33 can be made to be the same. Thus, the accuracy of the signal processing for identifying the rotation of the rotation shaft 3 performed by the IC 52 can be improved. Therefore, according to the present embodiment, the three magnetic sensors 31 to 33 can be collectively mounted on one substrate 45 to miniaturize the rotation detection device 11, and the accuracy of the rotation detection of the rotation shaft 3 can also be improved.

[0076] In addition, the cross-sectional shape of the wire winding portion 37 of the solenoid 36 of each of the magnetic sensors 31 to 33 is set to be a substantially elliptical shape with the major axis extending in the direction orthogonal to the mounting surface 46, and the cross-sectional shape of the coil 35 of each of the magnetic sensors 31 to 33 is set to be a substantially elliptical shape with the major axis extending in the direction orthogonal to the mounting surface 46. Thus, the size of the wire winding portion 37 in the direction orthogonal to the axial direction of the wire winding portion 37 and parallel to the mounting surface 46 of the substrate 45 can be reduced. Therefore, the three magnetic sensors 31 to 33 can be collectively mounted on a small-sized substrate 45, and a sufficient winding amount of the wire of the coil 35 can be ensured. In addition, the size of the wire winding portion 37 in the direction orthogonal to the mounting surface 46 of the substrate 45 can be increased, and the strength of the solenoid 36 can be improved.

[0077] (Arrangement of magnetic field detection unit)

[0078] Figure 12 Shows a state of a cross-section of the rotation detection device 11 and the housing 83 cut along the cutting line XII-XII as viewed from above in Figure 2 and along Figure 2 . As Figure 12As shown, the magnetic detection unit 30 is disposed on the outer peripheral side of the orbit T of the four magnetic field forming units 21 to 24 such that the distances between the magnetic wire materials 34 of the three magnetic sensors 31 to 33 and the axis X of the rotating shaft 3 are equal to each other. In addition, the magnetic detection unit 30 is disposed in the housing 83 such that the mounting surface 46 of the substrate 45 is not parallel to any of the rear surface of the front wall plate 84, the front surface of the rear wall plate 85, the right surface of the left wall plate 86, and the left surface of the right wall plate 87. In the present embodiment, the magnetic detection unit 30 is disposed such that the angle Q between the mounting surface 46 and the rear surface of the front wall plate 84 is, for example, about 75 degrees.

[0079] In this way, by disposing the magnetic detection unit 30 in the housing 83 such that the mounting surface 46 of the substrate 45 is not parallel to any of the rear surface of the front wall plate 84, the front surface of the rear wall plate 85, the right surface of the left wall plate 86, and the left surface of the right wall plate 87, it is possible to satisfy the following conditions: (a) the distances between the magnetic wire materials 34 of the three magnetic sensors 31 to 33 and the axis X of the rotating shaft 3 are equal to each other; (b) the three magnetic sensors 31 to 33 can be located on the outer peripheral side of the orbit T of the four magnetic field forming units 21 to 24; and (c) the magnetic detection unit 30 does not interfere with the wall portions 77 and 78 of the bracket 71. Moreover, the magnetic detection unit 30 can be accommodated in a small space within the housing 83 having a rectangular cross-sectional shape. As a result, the rotation detection device 11 can be miniaturized.

[0080] (Shape of the connecting member)

[0081] As Figure 8 shown, the first connecting member 41 of each of the magnetic sensors 31 to 33 has a crank shape or an L shape. The second connecting member 42 of each of the magnetic sensors 31 to 33 is the same as the first connecting member 41 and also has a crank shape or an L shape.

[0082] Specifically, among the three magnetic sensors 31 to 33, the first connecting member 41 of the magnetic sensor 31 disposed on the leftmost side in Figure 8 is formed such that one end side portion 41A (the lower end side portion in Figure 8 ) and the other end side portion 41B (the upper end side portion in Figure 8 ) extend in directions orthogonal to the mounting surface 46 of the substrate 45, and the middle portion extends parallel to the mounting surface 46 in a crank shape. In addition, the one end side portion 41A and the other end side portion 41B of the first connecting member 41 of the magnetic sensor 31 project from the bobbin 36 in directions orthogonal to the mounting surface 46. Further, the first connecting member 41 of the magnetic sensor 31 is such that the one end side portion 41A of the wire fixing the coil 35 is located closer to Figure 8On the left end side of the mounting surface 46, they are respectively provided on the bobbin 36. The second connecting member 42 of the magnetic sensor 31 is also formed in the same shape as the first connecting member 41 of the magnetic sensor 31, and is provided on the bobbin 36 in the same manner as the first connecting member 41 of the magnetic sensor 31.

[0083] In addition, among the three magnetic sensors 31 to 33, Figure 8 The first connecting member 41 of the magnetic sensor 33 arranged on the rightmost side in Figure 8 is formed in the same crank shape as the first connecting member 41 of the magnetic sensor 31 located on the leftmost side in Figure 8 On the right end side of the mounting surface 46, they are respectively provided on the bobbin 36. The second connecting member 42 of the magnetic sensor 33 is also formed in the same shape as the first connecting member 41 of the magnetic sensor 33, and is also provided on the bobbin 36 in the same manner as the first connecting member 41 of the magnetic sensor 33.

[0084] In addition, among the three magnetic sensors 31 to 33, the first connecting member 41 of the magnetic sensor 32 in the middle is formed in an L shape in which one end side portion 41A extends in a direction parallel to the mounting surface 46 of the substrate 45 and the other end side portion 41B extends in a direction orthogonal to the mounting surface 46. In addition, the first connecting member 41 of the magnetic sensor 32 is arranged on the bobbin 36 in such a manner that Figure 8 the one end side portion 41A of the wire fixing the coil 35 faces the left end side of the mounting surface 46 and protrudes from the bobbin 36. The second connecting member 42 of the magnetic sensor 32 is also formed in the same shape as the first connecting member 41 of the magnetic sensor 32, and is also provided on the bobbin 36 in the same manner as the first connecting member 41 of the magnetic sensor 32. In addition, in such a manner that the one end side portions 41A and 42A of the first connecting member 41 and the second connecting member 42 protruding from the bobbin 36 of the magnetic sensor 32 in the middle do not Figure 8 contact the bobbin 36 of the magnetic sensor 31 arranged on the leftmost side in Figure 6 (A) of Figure 6 (B), the shapes of both ends of the bobbin 36 of the magnetic sensor 31 are set (refer to

[0085] Here, by observing Figure 11 it can be seen that when the magnetic detection unit 30 is mounted on the mounting portions 79 and 80 of the bracket 71, the magnetic detection unit 30 is arranged such thatFigure 8 The lower part of Figure 8 the left part of the magnetic detection unit 30 faces right rearward. And the magnetic detection unit 30 is arranged on the outer peripheral side of the orbit T of the four magnetic field forming units 21 to 24 in such a manner that the distances between the magnetic wire materials 34 of the three magnetic sensors 31 to 33 and the axis X of the rotating shaft 3 are respectively equal to each other. In this state, in Figure 11 , the one - end - side portions 41A, 42A of the first connection member 41 and the second connection member 42 of the magnetic sensor 31 arranged at the rearmost side among the three magnetic sensors 31 to 33 extend left rearward from the left rear part of the bobbin 36 of the magnetic sensor 31, and their front ends are located behind the rotating shaft 3, the annular magnet 25, and the annular magnet 26. As a result, the one - end - side portions 41A, 42A of the first connection member 41 and the second connection member 42 of the magnetic sensor 31 do not contact any of the rotating shaft 3, the annular magnet 25, and the annular magnet 26. In addition, in Figure 11 , the one - end - side portions 41A, 42A of the first connection member 41 and the second connection member 42 of the magnetic sensor 33 arranged at the foremost side among the three magnetic sensors 31 to 33 extend left rearward from the left front part of the bobbin 36 of the magnetic sensor 33, and their front ends are located in front of the rotating shaft 3, the annular magnet 25, and the annular magnet 26. As a result, the one - end - side portions 41A, 42A of the first connection member 41 and the second connection member 42 of the magnetic sensor 33 do not contact any of the rotating shaft 3, the annular magnet 25, and the annular magnet 26. In addition, in Figure 11 , the one - end - side portions 41A, 42A of the first connection member 41 and the second connection member 42 of the magnetic sensor 32 arranged in the middle among the three magnetic sensors 31 to 33 extend right rearward from the left rear part of the bobbin 36 of the magnetic sensor 32, and their front ends are located on the right side of the rotating shaft 3, the annular magnet 25, and the annular magnet 26. As a result, the one - end - side portions 41A, 42A of the first connection member 41 and the second connection member 42 of the magnetic sensor 32 do not contact any of the rotating shaft 3, the annular magnet 25, and the annular magnet 26.

[0086] In this way, in each of the magnetic sensors 31 and 33 located at both ends, the first connection member 41 and the second connection member 42 are respectively formed in a crank shape, and these first connection members 41 and second connection members 42 are arranged on the bobbin 36 in such a manner that their one - end - side portions 41A, 42A are located on the end side of the mounting surface 46 of the substrate 45 compared to the other - end - side portions 41B, 42B. Thus, as Figure 12As shown, even when the magnetic detection unit 30 is disposed in a small space within the outer shell 83, it is possible to prevent the end-side portions 41A and 42A of the first connection member 41 and the second connection member 42 of each of the magnetic sensors 31 and 33 from coming into contact with the rotating shaft 3, the annular magnet 25, or the annular magnet 26. Thereby, miniaturization of the rotation detection device 11 can be achieved.

[0087] In addition, in the case of the middle magnetic sensor 32, the first connection member 41 and the second connection member 42 are each formed in an L shape, and the first connection member 41 and the second connection member 42 are disposed on the bobbin 36 such that their end-side portions 41A project from the bobbin 36 in a direction parallel to the mounting surface 46 of the substrate 45. Thus, even when the magnetic detection unit 30 is disposed in a small space within the outer shell 83, it is possible to prevent the end-side portions 41A and 42A of the first connection member 41 and the second connection member 42 of the magnetic sensor 32 from coming into contact with the rotating shaft 3, the annular magnet 25, or the annular magnet 26. Thereby, miniaturization of the rotation detection device 11 can be achieved.

[0088] (Position of the connection member in the axial direction of the rotating shaft)

[0089] As Figure 7 shown, the three magnetic sensors 31 to 33 are arranged on the mounting surface 46 of the substrate 45 such that the positions in the vertical direction (axial direction of the rotating shaft 3) of the respective magnetic wire materials 34 are the same. In this state, the position in the vertical direction of the first connection member 41 of the middle magnetic sensor 32 among the three magnetic sensors 31 to 33 is different from the positions in the vertical direction of the first connection members 41 of the magnetic sensors 31 and 33 at both ends among the three magnetic sensors 31 to 33. Specifically, the first connection member 41 of the middle magnetic sensor 32 is located above the first connection members 41 of the magnetic sensors 31 and 33 at both ends. On the other hand, the positions in the vertical direction of the first connection members 41 of the two magnetic sensors 31 and 33 at both ends are the same.

[0090] The first connection member 41 of the magnetic sensor 32 is located above the first connection members 41 of the magnetic sensors 31 and 33, thereby ensuring an insulation distance (e.g., 1 mm) between the first connection members 41 of two adjacent magnetic sensors among the three magnetic sensors 31 to 33. Specifically, as Figure 7 shown, the distance d between the end-side portion 41A of the first connection member 41 of the magnetic sensor 31 and the end-side portion 41A of the first connection member 41 of the magnetic sensor 32 is equal to or greater than the insulation distance. In addition, the distance between the end-side portion 41A of the first connection member 41 of the magnetic sensor 32 and the end-side portion 41A of the first connection member 41 of the magnetic sensor 33 is greater than the distance d and is equal to or greater than the insulation distance.

[0091] In addition, as Figure 10 shown, the distance e between the connection pad 53 of the other end side portion 41B of the first connection member 41 to which the magnetic sensor 31 is connected and the connection pad 53 of the other end side portion 41B of the first connection member 41 to which the magnetic sensor 32 is connected is equal to or greater than the insulation distance. In addition, the distance f between the connection pad 53 of the other end side portion 41B of the first connection member 41 to which the magnetic sensor 32 is connected and the connection pad 53 of the other end side portion 41B of the first connection member 41 to which the magnetic sensor 33 is connected is equal to or greater than the insulation distance. In addition, the screw 56 of the mounting portion 80 for mounting the magnetic detection unit 30 to the bracket 71 is inserted into the screw insertion hole 47 formed at the corner of the upper portion of the substrate 45, and the screw 56 has conductivity. The distance g between the head 56A of the screw 56 and the connection pad 53 of the other end side portion 41B of the first connection member 41 to which the magnetic sensor 32 is connected is equal to or greater than the insulation distance. In addition, the distance h between the head 56A of the screw 56 and the connection pad 53 of the other end side portion 41B of the first connection member 41 to which the magnetic sensor 33 is connected is also equal to or greater than the insulation distance.

[0092] In addition, the vertical position of the second connection member 42 of the middle magnetic sensor 32 among the three magnetic sensors 31 to 33 is different from the vertical positions of the second connection members 42 of the magnetic sensors 31 and 33 at both ends among the three magnetic sensors 31 to 33. Specifically, the second connection member 42 of the middle magnetic sensor 32 is located below the second connection members 42 of the magnetic sensors 31 and 33 at both ends. On the other hand, the vertical positions of the second connection members 42 of the two magnetic sensors 31 and 33 at both ends are the same.

[0093] The second connection member 42 of the magnetic sensor 32 is located below the second connection members 42 of the magnetic sensors 31 and 33, thereby ensuring an insulation distance between the second connection members 42 of two adjacent magnetic sensors among the three magnetic sensors 31 to 33. That is, as Figure 7 shown, the distance i between the one end side portion 42A of the second connection member 42 of the magnetic sensor 31 and the one end side portion 42A of the second connection member 42 of the magnetic sensor 32, and the distance between the one end side portion 42A of the second connection member 42 of the magnetic sensor 32 and the one end side portion 42A of the second connection member 42 of the magnetic sensor 33 are both equal to or greater than the insulation distance.

[0094] In addition, as Figure 10As shown, the distance j between the connection pads 53 of the other end side portion 42B of the second connection member 42 to which the magnetic sensor 31 is connected and the connection pads 53 of the other end side portion 42B of the second connection member 42 to which the magnetic sensor 32 is connected is equal to or greater than the insulation distance. Further, the distance k between the connection pads 53 of the other end side portion 42B of the second connection member 42 to which the magnetic sensor 32 is connected and the connection pads 53 of the other end side portion 42B of the second connection member 42 to which the magnetic sensor 33 is connected is equal to or greater than the insulation distance. In addition, the screw 56 of the mounting portion 79 for mounting the magnetic detection unit 30 to the bracket 71 is inserted into the screw insertion hole 47 formed at the corner portion of the lower part of the substrate 45, and this screw 56 has conductivity. The distance m between the head 56A of this screw 56 and the connection pad 53 of the other end side portion 42B of the second connection member 42 to which the magnetic sensor 31 is connected is equal to or greater than the insulation distance. Further, the distance n between the head 56A of the screw 56 and the connection pad 53 of the other end side portion 42B of the second connection member 42 to which the magnetic sensor 32 is connected is equal to or greater than the insulation distance. In addition, the distance between adjacent wirings 54 is also equal to or greater than the insulation distance.

[0095] Thus, in the rotation detection device 11 according to the embodiment of the present invention, the first connection member 41 of the magnetic sensor 32 located in the middle is arranged above the first connection members 41 of the respective magnetic sensors 31 and 33 located at both ends, and the second connection member 42 of the magnetic sensor 32 located in the middle is arranged below the second connection members 42 of the respective magnetic sensors 31 and 33 located at both ends. As a result, it is possible to ensure the insulation distance between the first connection members 41 of two adjacent magnetic sensors among the three magnetic sensors 31 to 33 and the insulation distance between the second connection members 42, and it is possible to make the interval between two adjacent magnetic sensors extremely small in the mounting surface 46 of the substrate 45. Therefore, it is possible to reduce the area of the mounting surface 46 of the substrate 45 on which the three magnetic sensors 31 to 33 are mounted, and it is possible to reduce the size of the substrate 45. Therefore, it is possible to miniaturize the rotation detection device 11, and it is possible to realize a rotation detection device 11 that can be assembled in a small electric motor 1.

[0096] In addition, in the two magnetic sensors 31 and 33 located at both ends, the vertical positions of the first connection members 41 coincide with each other, and the vertical positions of the second connection members 42 coincide with each other. Therefore, as the two magnetic sensors 31 and 33 arranged at both ends, it is possible to use two common magnetic sensors, that is, two magnetic sensors having the same bobbin 36 shape and the same arrangement of the first connection member 41 and the second connection member 42. As a result, it is possible to reduce the mold cost for forming the bobbin of the magnetic sensor and simplify the manufacture of the rotation detection device 11. In addition, observing Figure 7 it can be seen that in the present embodiment, the magnetic sensor 33 is arranged with the opposite vertical orientation with respect to the magnetic sensor 31.

[0097] (Operation of the rotation detection device)

[0098] Figure 13 The operation of the rotation detection device 11 is shown. Hereinafter, as an example of the operation of the rotation detection device 11, Figure 13 the operation during the period when the angle of the rotation axis 3 is set to 0 degrees when the magnetic field forming unit 21 passes near the magnetic sensor 31 and the rotation axis 3 rotates clockwise from 0 degrees to 150 degrees will be described.

[0099] In Figure 13 six states of the rotation detection device 11 are depicted. In Figure 13 , (A) shows the state when the rotation angle of the rotation axis 3 is 0 degrees, (B) shows the state when the rotation angle of the rotation axis 3 is 30 degrees, and (C) shows the state when the rotation angle of the rotation axis 3 is 60 degrees. And, (D) shows the state when the rotation angle of the rotation axis 3 is 90 degrees, (E) shows the state when the rotation angle of the rotation axis 3 is 120 degrees, and (F) shows the state when the rotation angle of the rotation axis 3 is 150 degrees. In addition, Figure 13 S1 in

[0100] In Figure 13 , in (A), the angle of the rotation axis 3 is 0 degrees. When the magnetic field forming unit 21 passes near the magnetic sensor 31, the downward magnetic field formed by the magnetic field forming unit 21 acts on the magnetic wire 34 of the magnetic sensor 31. Just before the downward magnetic field acts on the magnetic wire 34, if the magnetization direction of the magnetic wire 34 is upward, then when the downward magnetic field acts on the magnetic wire 34, due to the large Barkhausen effect, the magnetization direction of the magnetic wire 34 instantaneously reverses from upward to downward. If the magnetization direction of the magnetic wire 34 of the magnetic sensor 31 instantaneously reverses from upward to downward, then by electromagnetic induction, a relatively large current flows through the coil 35 of the magnetic sensor 31 in a short time, and a positive-direction pulse P1 is output from the coil 35, for example.

[0101] Then, the rotation axis 3 rotates clockwise. When the angle of the rotation axis 3 reaches 30 degrees, the magnetic field forming unit 21 passes near the magnetic sensor 32. At this time, based on the same principle as when the magnetic field forming unit 21 passes near the magnetic sensor 31, the magnetization direction of the magnetic wire 34 of the magnetic sensor 32 instantaneously reverses from upward to downward, and a positive-direction pulse P2 is output from the coil 35 of the magnetic sensor 32.

[0102] Then, the rotating shaft 3 further rotates clockwise. When the angle of the rotating shaft 3 reaches 60 degrees, the magnetic field forming portion 21 passes near the magnetic sensor 33. At this time, based on the same principle as when the magnetic field forming portion 21 passes near the magnetic sensor 31, the magnetization direction of the magnetic wire 34 of the magnetic sensor 33 instantaneously reverses from the upper direction to the lower direction, and a positive-direction pulse P3 is output from the coil 35 of the magnetic sensor 33.

[0103] Then, the rotating shaft 3 further rotates clockwise. When the angle of the rotating shaft 3 reaches 90 degrees, the magnetic field forming portion 22 passes near the magnetic sensor 31, and the upward magnetic field formed by the magnetic field forming portion 22 acts on the magnetic wire 34 of the magnetic sensor 31. When this upward magnetic field acts on the magnetic wire 34, due to the large Barkhausen effect, the magnetization direction of the magnetic wire 34 instantaneously reverses from the lower direction to the upper direction. If the magnetization direction of the magnetic wire 34 of the magnetic sensor 31 instantaneously reverses from the lower direction to the upper direction, then due to electromagnetic induction, a relatively large current flows through the coil 35 of the magnetic sensor 31 in a short time, and a pulse P4 is output from the coil 35. In addition, when the magnetic field direction of the magnetic wire 34 reverses from the lower direction to the upper direction, the direction of the current flowing through the coil 35 is opposite to the direction of the current flowing through the coil 35 when the magnetic field direction of the magnetic wire 34 reverses from the upper direction to the lower direction. Therefore, when the magnetic field direction of the magnetic wire 34 reverses from the upper direction to the lower direction, if the direction of the pulse output from the coil 35 is the positive direction, then the direction of the pulse output from the coil 35 when the magnetic field direction of the magnetic wire 34 reverses from the lower direction to the upper direction becomes the negative direction. Therefore, the pulse P4 becomes a negative-direction pulse.

[0104] Then, the rotating shaft 3 rotates clockwise. When the angle of the rotating shaft 3 reaches 120 degrees, the magnetic field forming portion 22 passes near the magnetic sensor 32. At this time, based on the same principle as when the magnetic field forming portion 22 passes near the magnetic sensor 31, the magnetization direction of the magnetic wire 34 of the magnetic sensor 32 instantaneously reverses from the lower direction to the upper direction, and a negative-direction pulse P5 is output from the coil 35 of the magnetic sensor 32.

[0105] Then, the rotating shaft 3 further rotates clockwise. When the angle of the rotating shaft 3 reaches 150 degrees, the magnetic field forming portion 22 passes near the magnetic sensor 33. At this time, based on the same principle as when the magnetic field forming portion 22 passes near the magnetic sensor 31, the magnetization direction of the magnetic wire 34 of the magnetic sensor 33 instantaneously reverses from the lower direction to the upper direction, and a negative-direction pulse P6 is output from the coil 35 of the magnetic sensor 33.

[0106] Detection signals S1 including pulses P1 and P4 output from the coil 35 of the magnetic sensor 31, detection signals S2 including pulses P2 and P5 output from the coil 35 of the magnetic sensor 32, and detection signals S3 including pulses P3 and P6 output from the coil 35 of the magnetic sensor 33 are respectively input to an IC 52 provided on the back surface of a substrate 45. The IC 52 calculates the rotation angle or rotation amount of the rotation shaft 3 based on the detection signals S1 to S3 respectively output from the magnetic sensors 31 to 33. As a method for calculating the rotation angle or rotation amount of the rotation shaft 3, for example, the method described in the above-mentioned Patent Document 1 can be used. In addition, although not shown in the drawings, the IC 52 is electrically connected to a drive control circuit of an electric motor 1 provided outside the rotation detection device 11, and the IC 52 outputs a signal indicating the rotation angle or rotation amount of the rotation shaft 3 to the drive control circuit of the electric motor 1.

[0107] In addition, in the above-described embodiment, the first connection member 41 of the middle magnetic sensor 32 is disposed above the first connection members 41 of the respective magnetic sensors 31 and 33 at both ends, and the second connection member 42 of the middle magnetic sensor 32 is disposed below the second connection members 42 of the respective magnetic sensors 31 and 33 at both ends, thereby ensuring the insulation distance between the first connection members 41 of two adjacent magnetic sensors and the insulation distance between the second connection members 42, respectively. However, the first connection member 41 of the middle magnetic sensor 32 may be disposed below the first connection members 41 of the respective magnetic sensors 31 and 33 at both ends, and the second connection member 42 of the middle magnetic sensor 32 may be disposed above the second connection members 42 of the respective magnetic sensors 31 and 33 at both ends, thereby ensuring the insulation distance between the first connection members 41 of two adjacent magnetic sensors and the insulation distance between the second connection members 42, respectively. Further, the first connection member 41 and the second connection member 42 of the middle magnetic sensor 32 may be disposed above the first connection member 41 and the second connection member 42 of the magnetic sensor 31 at one end, and the first connection member 41 and the second connection member 42 of the magnetic sensor 33 at the other end may be disposed above the first connection member 41 and the second connection member 42 of the middle magnetic sensor 32, thereby ensuring the insulation distance between the first connection members 41 of two adjacent magnetic sensors and the insulation distance between the second connection members 42, respectively. Further, the first connection member 41 and the second connection member 42 of the middle magnetic sensor 32 may be disposed below the first connection member 41 and the second connection member 42 of the magnetic sensor 31 at one end, and the first connection member 41 and the second connection member 42 of the magnetic sensor 33 at the other end may be disposed below the first connection member 41 and the second connection member 42 of the middle magnetic sensor 32, thereby ensuring the insulation distance between the first connection members 41 of two adjacent magnetic sensors and the insulation distance between the second connection members 42, respectively.

[0108] In addition, in the above-described embodiment, the distance between the magnetic wire disposition portion 38 of the bobbin 36 of the middle magnetic sensor 32 and the mounting surface 46 of the substrate 45 is made smaller than the distances between the magnetic wire disposition portions 38 of the bobbins 36 of the respective magnetic sensors 31 and 33 at both ends, and the distances between the magnetic wire disposition portions 38 of the bobbins 36 of the respective magnetic sensors 31 and 33 at both ends and the mounting surface 46 are made equal to each other. However, the magnitude relationship of the distances between the magnetic wire disposition portions 38 of the three magnetic sensors 31 to 33 and the mounting surface 46 is not limited to this. For example, when the magnetic detection unit 30 is disposed on the outer peripheral side of the tracks of the four magnetic field forming units 21 to 24 and is disposed in relation to Figure 11In the case of different positions, etc., the distances between the magnetic wire materials 34 of the three magnetic sensors 31 to 33 and the axis X of the rotating shaft 3 can also be made equal to each other, and the distances between the magnetic wire material arrangement parts 38 of the three magnetic sensors 31 to 33 and the mounting surface 46 can be set to different values respectively.

[0109] In addition, in the above-described embodiment, although the case where the magnetic wire material arrangement part 38 is formed in the groove of the wire winding part 37 is taken as an example, the magnetic wire material arrangement part may also be a hole formed in the wire winding part 37.

[0110] In addition, in the above-described embodiment, as Figure 5 shown, although the case where four magnetic field forming parts 21 to 24 are formed by the annular magnet 25 having magnetic poles 25A to 25D and the annular magnet 26 having magnetic poles 26A to 26D is taken as an example, the method of forming the four magnetic field forming parts is not limited to this. For example, it is also possible to form four magnetic field forming parts by a single magnet having a total of 8 magnetic poles as shown in Figure 5 . In addition, it is also possible to form four magnetic field forming parts by four bar-shaped magnets having an N pole on one end side and an S pole on the other end side. In addition, it is also possible to form four magnetic field forming parts by eight independent magnets.

[0111] In addition, in the above-described embodiment, although the outer shape of the wire winding part 37 of the bobbin 36 of each magnetic sensor 31 to 33 is set to a cylindrical shape with a substantially elliptical cross-sectional shape, the outer shape of the wire winding part 37 may also be set to a cylindrical shape with a circular cross-sectional shape, or may be set to a columnar shape with a polygonal cross-sectional shape.

[0112] In addition, the number of magnetic sensors may also be four or more. In addition, the number of magnetic field forming parts may also be two, six, or eight or more. In addition, the rotating device is not limited to an electric motor.

[0113] In addition, other rotation detection devices such as an optical encoder that optically detects the rotation of the rotating shaft 3 may also be provided above the bracket 71 of the rotation detection device 11.

[0114] In addition, the present invention can be appropriately changed within the scope not violating the gist or idea of the invention that can be read from the claims and the entire specification, and the magnetic detection device and the rotation detection device accompanying such a change are also included in the technical idea of the present invention.

Claims

1. A magnetic detection device comprising at least two magnetic field generating units that move around a rotating shaft as the rotating shaft rotates and generate magnetic fields in one and another axial directions of the rotating shaft, respectively, and detecting the rotation of the rotating shaft, wherein the magnetic detection device detects the magnetic fields, the magnetic detection device comprising: at least three magnetic sensors; and a substrate having a mounting surface on which the three magnetic sensors are mounted, Each of the above magnetic sensors has: Magnetic wire, which produces a large Barkhausen effect; a coil disposed on the outer periphery of the magnetic wire; and The bobbin has a columnar outer shape and comprises a wire winding portion around which the wire of the coil is wound, and a magnetic wire arrangement portion which is a space extending in the axial direction of the wire winding portion and in which the magnetic wire is arranged. The three magnetic sensors are arranged on the loading surface in such a manner that the elongated directions of their respective magnetic wires are parallel to the loading surface. The three magnetic sensors and the substrate are arranged on the outer peripheral side of the tracks of the two magnetic field forming parts in such a manner that the elongated directions of the magnetic wires of the respective magnetic sensors are parallel to the axial directions of the rotating shaft. In each of the three magnetic sensors, the position of the magnetic wire arrangement portion of the winding bobbin is set so that the distances between the magnetic wires of the respective three magnetic sensors and the rotating shaft are equal to each other. The distance between the magnetic wire arrangement portion of the winding bobbin of the magnetic sensor located in the middle of the three magnetic sensors and the loading surface is smaller than the distance between the magnetic wire arrangement portion of the winding bobbin of each magnetic sensor located at both ends of the three magnetic sensors and the loading surface.

2. The magnetic detection device according to claim 1, characterized in that In the winding tubes of the above-mentioned magnetic sensors, the above-mentioned magnetic wire configuration portion is formed from the peripheral surface of the above-mentioned wire winding portion toward the interior of the above-mentioned wire winding portion, and is a groove extending along the axial direction of the above-mentioned wire winding portion. The above-mentioned groove formed on the wire winding portion of the winding tube of the magnetic sensor located in the middle among the above-mentioned three magnetic sensors is deeper than the above-mentioned groove formed on the wire winding portion of the winding tubes of each magnetic sensor located at both ends among the above-mentioned three magnetic sensors.

3. The magnetic detection device according to claim 1 or 2, characterized in that: The cross-sectional shape of the coil of each magnetic sensor is a substantially elliptical shape with a major axis extending in a direction perpendicular to the placement surface.

4. The magnetic detection device according to claim 1 or 2, characterized in that: The cross-sectional shape of the wire winding portion of the bobbin of each of the magnetic sensors is a substantially elliptical shape with a major axis extending in a direction perpendicular to the placement surface.

5. A rotation detection device for detecting the rotation of a rotating shaft, the rotation detection device comprising: at least two magnetic field forming units that move around the rotating shaft as the rotating shaft rotates and respectively form magnetic fields in one direction and the other direction of the axial direction of the rotating shaft; and a magnetic detection unit that does not move with the rotation of the rotation shaft and detects the magnetic field formed by the two magnetic field forming units; The magnetic detection unit includes: at least three magnetic sensors; and a substrate having a mounting surface on which the three magnetic sensors are mounted, Each of the above magnetic sensors has: Magnetic wire, which produces a large Barkhausen effect; a coil disposed on the outer periphery of the magnetic wire; and The bobbin has a columnar outer shape and comprises a wire winding portion around which the wire of the coil is wound, and a magnetic wire arrangement portion which is a space extending in the axial direction of the wire winding portion and in which the magnetic wire is arranged. The three magnetic sensors are arranged on the loading surface in such a manner that the elongated directions of their respective magnetic wires are parallel to the loading surface, and the magnetic detection parts are arranged on the outer peripheral side of the tracks of the two magnetic field forming parts in such a manner that the elongated directions of the magnetic wires of the magnetic sensors are parallel to the axial directions of the rotating shaft. In each of the magnetic sensors, the position of the magnetic wire arrangement part of the winding bobbin is set so that the distances between the magnetic wires of the three magnetic sensors and the rotating shaft are equal to each other, and the distance between the magnetic wire arrangement part of the winding bobbin of the magnetic sensor located in the middle among the three magnetic sensors and the loading surface is smaller than the distance between the magnetic wire arrangement part of the winding bobbin of each of the magnetic sensors located at both ends among the three magnetic sensors and the loading surface.

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