JP2000283704A - Rotation detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of components and costs, to attain compactness and a thin type, and to improve accuracy in detecting rotation by fixing a rotation detecting element to detect the rotation of a disk-shaped rotor to the center of rotation on one surface side of a circuit board facing the disk-shaped rotor so as to be surrounded with a ring-shaped contact part. SOLUTION: A circular fitting shaft part 71 to be fitted into circular bearing recessed parts 45 and 46 is formed in one face parts of driven gears 39 and 40, and a ring-shaped contact part 72 is formed in the other face parts so as to surround holding holes 47 and 48. The ring-shaped contact part 72 is brought into contact with one surface side of a circuit board 41 to surround magneto-resistive elements 57 and 58. In the magneto-resistive elements 57 and 58, their magnetic resistances are changed due to the number of magnetic fluxes that intersect the magneto-resistive elements 57 and 58. With reference to the case that the magnetic fluxes of disk-shaped magnets 49 and 50 are directed in the direction in which the density of a magnetic flux ϕ1 that intersects the magneto-resistive elements 57 and 58 is zero, their magnetic resistances are increased according to an increase in the number of magnetic fluxes. As the magneto-resistive elements are provided at the centers of rotation of the driven gears, it is possible to detect rotation while avoiding vibrations associated with the rotation of the rotor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a rotation detecting device used for a steering angle sensor for generating rotation angle information in accordance with rotation of a steering wheel of an automobile or the like.

[0002]

2. Description of the Related Art Conventionally, a steering angle sensor that generates rotation angle information in accordance with rotation of a steering wheel has been known. The steering angle sensor incorporates a rotation detecting device for detecting the rotation of the steering wheel.

FIG. 22 is a conceptual diagram showing an example of the rotation detecting device. In FIG. 22A, reference numeral 1 denotes a lower housing, and reference numeral 2 denotes an upper housing. A storage chamber 3 is provided between the lower housing 1 and the upper housing 2, and the storage chamber 3 is provided with an annular drive gear 4 that is rotated with rotation of a steering wheel (not shown).

A driven gear 5 as a disk-shaped rotating body meshes with the annular driving gear 4, and reference numeral 6 denotes a rotating shaft thereof. Circular bearing recesses 7 and 8 are provided in both housings 1 and 2, and both ends of the rotating shaft 6 are rotatably supported by the circular bearing recesses 7 and 8. An encoder plate 9 is provided on the rotating shaft 6 so as to be integrally rotatable. As shown in FIG. 22 (b), fan-shaped magnetic shielding portions 9a and fan-shaped magnetic transmitting portions 9b are alternately formed in the circumferential direction of the encoder plate 9 in the peripheral portion thereof.

The lower housing 1 is provided with a magnet 10 facing the periphery of the encoder plate 9, and the upper housing 2 is a Hall element as a rotation detecting element for detecting rotation of the driven gear 5 facing the magnet 10. 11 are provided.

When the driven gear 5 rotates, the encoder plate 9 is rotated integrally therewith. According to this rotation detecting device, when the fan-shaped magnetic shielding portion 9a of the encoder plate 9 passes right above the magnet 10, the hole is removed. The amount (density) of the magnetic flux Φ perpendicular to the element 11 decreases, and the fan-shaped magnetic transmission portion 9
When b passes right above the magnet 10, the amount (density) of the magnetic flux Φ that vertically crosses the Hall element 11 increases. As a result, the Hall element 11 outputs a pulse-like signal P as schematically shown in FIG. 22C with the rotation of the driven gear 5, whereby the rotation of the driven gear 5 is detected.

[0007]

In this conventional rotation detecting device, the rotation of the driven gear 5 can be digitally detected by using the pulse signal P. Therefore, at first glance, the rotation angle of the driven gear 5 can be accurately determined. Seems detectable. However, since the Hall element 11 is disposed so as to face the peripheral portion of the encoder plate 9, if the fitting between the upper and lower circular bearing recesses 7, 8 and the rotary shaft 6 is not accurate, the encoder plate 9 is not provided. In some cases, the magnetic flux Φ may be disturbed due to the vibration caused by the rotation of the driven gear 5, and the rotation of the driven gear 5 cannot be detected accurately.

The reason why the rotation of the driven gear 5 cannot be accurately detected is that the rotation of the driven gear 5 is controlled by the magnetic shielding between the fan-shaped magnetic shielding portion 9a and the fan-shaped magnetic transmitting portion 9b of the encoder plate 9.
Although it is detected by magnetic transmission, it is conceivable that there is a magnetic flux Φ that leaks and crosses the Hall element 11 vertically.

In addition, not only the annular drive gear 4 and the driven gear 5 but also the encoder plate 9, the magnet 10, and the Hall element 11 must be provided in the storage chamber 3. However, there is also a disadvantage that it becomes complicated and large.

An object of the present invention is to provide a rotation detecting device which can be reduced in size, cost, and thickness by reducing the number of parts, and which can improve the accuracy of detecting the rotation of a rotating body.

[0011]

According to a first aspect of the present invention, there is provided a rotation detecting apparatus, wherein a circuit board is mounted and a disk-shaped rotator is cooperated with the circuit board in order to solve the above problems. A circular bearing recess is formed in the housing to be housed, and a circular fitting shaft that is rotatably supported by being fitted into the circular bearing recess is formed on one end surface of the disc-shaped rotating body, On the other end surface portion of the disc-shaped rotator, an annular contact portion that is in contact with the circuit board is formed so as to surround the center of rotation, and the circuit board has one surface facing the disc-shaped rotator. A rotation detecting element for detecting the rotation of the disk-shaped rotator is fixed on the center of rotation so as to be surrounded by the annular contact portion.

According to the first aspect of the present invention, only one end of the disk-shaped rotator is pivotally supported, and the other end is slidably contacted with the circuit board. Since the detection element is provided, it is possible to detect the rotation while minimizing the runout and the like due to the rotation of the disk-shaped rotating body without increasing the accuracy of the bearing portion. Therefore, the rotation detection accuracy of the disk-shaped rotator is improved. Further, an annular contact portion is formed on the other end surface of the disc-shaped rotating body, and the annular contact portion is slid on the circuit board so as to surround the rotation detecting element. Since it can be arranged close to the rotating body, it is possible to reduce the thickness, the size, and the cost.

According to a second aspect of the present invention, in the rotation detecting device according to the first aspect, the rotation detecting element detects a change in magnetic flux accompanying rotation of the disk-shaped rotator. A detection element, wherein the disc-shaped rotator is provided with a magnet at the center of rotation. The invention according to claim 3 of the present application is the rotation detecting device according to claim 2, wherein the magnet has an N pole and an S pole on one surface side facing the magnetic change detecting element.
And a magnetic change detecting element, wherein the magnetic change detecting element is a magnetoresistive element that generates an analog electric signal by changing a magnetic resistance based on a change in a direction of a magnetic flux accompanying rotation of the disk-shaped rotator. Things.

According to the second and third aspects of the present invention, the rotation detection accuracy of the rotating body can be improved, and the rotation can be detected with a reduced number of parts. There is an effect that the overall size can be reduced.

According to a fourth aspect of the present invention, in the rotation detecting device according to the third aspect, the disk-shaped rotator is meshed with an annular drive gear forming a part of a steering angle sensor. This is a driven gear that is driven and rotated, wherein the annular drive gear is rotated with the rotation of a steering wheel. According to the present invention, the rotation angle of the steering wheel can be accurately detected.

According to a fifth aspect of the present invention, in the rotation detecting device, a magnet is provided at a rotation center of the rotating body, and the magnet has an N pole and an S pole on one surface side. Characterized in that a magnetoresistive element for generating an analog electric signal by changing a resistance based on a change in the direction of a magnetic flux accompanying rotation of the rotator is provided on a center of rotation of the rotator to detect It is.

According to the fifth aspect of the present invention, since the magnetoresistive element is arranged on the center of rotation of the rotating body,
Rotation can be detected while avoiding vibrations and the like caused by the rotation of the rotator as much as possible, so that the rotation detection accuracy of the rotator is improved. In addition, since rotation can be detected with a reduced number of components, the rotation detection device can be made compact as a whole.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a rotation detecting device according to the present invention is applied to a steering angle sensor will be described below with reference to FIGS. <Description of Schematic Configuration of Steering Angle Sensor> FIG. 1 is a partially enlarged view showing a state where the steering angle sensor is incorporated in a storage recess formed on the lower surface of the lower cover member shown in FIG.
FIG. 2A is a perspective view showing a state in which a steering angle sensor having a rotation detecting device according to the present invention is incorporated in a rotary connector device, and FIG. 2B is a view showing a state where a rotary connector is connected to a base member constituting a part of a combination switch. It is the schematic which shows the state which attached the apparatus. 3 is a perspective view showing the entire configuration of the steering angle sensor, FIG. 4 is an exploded perspective view when the steering angle sensor is disassembled and viewed from the circuit board side, and FIG. Exploded perspective view from the side of the housing, FIG.
4 is an enlarged view of the retaining member shown in FIGS. 4 and 5, and FIG. 7 is an explanatory diagram for explaining a state in which the annular drive gear shown in FIGS. 4 and 5 is retained using the retaining member. 8 to 13 are explanatory views for explaining the assembly of the steering angle sensor. 14 and 15 are enlarged plan views showing the driven gear shown in FIGS. 4 and 5 viewed from the lower surface and the upper surface, respectively. FIG. 16 is a diagram for explaining the magnetic poles of the magnet shown in FIGS. FIG. 17 is an explanatory diagram for explaining the magnetization of the magnet, FIG. 18 is a schematic diagram for explaining the magnetizing state of the magnet, and FIG. FIG. 20 is a schematic diagram for explaining the principle of rotation detection based on FIG. 20, and FIG. 20 is a diagram showing an analog electric signal generated based on the rotation of the magnet.

In FIG. 2A, reference numeral 20 denotes a rotary connector device. The rotary connector device 20 has a lower cover member 21 and an upper cover member 22. The lower cover member 21 is fixed to a known base member 4 which constitutes a part of a combination switch device as shown in FIG. The lower cover member 21 includes the annular peripheral wall 2.
3 is formed, and the upper cover member 22 is
It is rotatably supported on.

An engagement projection 24 is formed on the upper cover member 22, and the upper cover member 22 is connected to a steering wheel (not shown) by the engagement projection 24, and is rotated with the rotation of the steering wheel.

Lower cover member 21 and upper cover member 22
A spiral flexible flat cable 25 for electrically connecting the electric equipment on the steering wheel side and the electric equipment on the vehicle body side is provided between them. One end of the spiral flexible flat cable 25 is fixed to the lower cover member 21, and the other end is fixed to the upper cover member 22.

An insertion hole 26 through which the steering shaft is inserted is formed in the center of the upper cover member 22. A cylindrical wall 27 is formed in the upper cover member 22 so as to surround the insertion hole 26. Upper cover member 2
2 and the lower cover member 21 are connected in the axial direction by an attachment member 28.

As shown in FIG. 1, the attachment member 28 has a flange portion 29 and elastically curved plate portions 30, 30 '.
And An opening 31 is formed in the elastic curved plate portion 30. On the inner peripheral surface of the cylindrical wall 27, an abutting step portion 33 with which the upper end of the elastic curved plate portion 30 'abuts and an engaging claw 34 engaging with the opening 31 are formed at appropriate intervals in the circumferential direction. I have.

As shown in FIGS. 1 and 2B, a storage recess 36 for storing the flange portion 29 of the attachment member 28 and a storage recess for storing the steering angle sensor 35 are provided on the lower surface of the lower cover member 21. 36 'are formed. The steering angle sensor 35 has a thin plate shape as shown in FIG.

The steering angle sensor 35 includes a housing 37, an annular driving gear 38, and a driven gear 3 as shown in FIGS.
9 and 40 and a circuit board 41. A through hole 42 is formed in the center of the housing 37, and an annular peripheral wall 43 concentric with the through hole 42 is formed so as to surround the through hole 42. Notches 44 are formed in the annular peripheral wall 43 at appropriate intervals in the circumferential direction.

The housing 37 has a circular bearing recess 45 and a circular bearing recess 46 formed adjacent to the through hole 42. In the circular bearing recesses 45 and 46, driven gears 39 and 40 as disc-shaped rotating bodies are rotatably supported. Reference numerals 39a and 40a denote driven gears 39,
Forty teeth are shown. Holding holes 47 and 48 are formed in the rotation center portions of the driven gears 39 and 40, and the holding holes 47 and 48 are formed.
Disk-shaped magnets 49 and 50 are fitted in the first and second plates.

The annular drive gear 38 has teeth 51, a pair of engaging claws 52, and an outer peripheral flange 53. A pair of engaging claws 5
2 is engaged with a pair of engagement recesses 54 formed on the lower surface of the flange portion 29 of the attachment member 28 as shown in FIG.

The circuit board 41 has through holes 55 corresponding to the through holes 42. On one side of the circuit board 41, a circuit component 56 for forming a circuit for generating rotation angle information in accordance with the rotation of the steering wheel, and a rotation detecting element (here, a rotation detecting element for detecting the rotation of the driven gears 39 and 40). A magnetoresistive element 57 as a magnetic change detecting element,
58) is mounted as shown in FIGS. In FIG. 1, reference numeral 57a denotes a terminal of the magnetoresistive element 57.

The magnetoresistive elements 57, 58 are located on the rotation center O1 of the driven gears 39, 40 (see FIG. 1).
Together with the driven gears 39 and 40 and the disc-shaped magnets 49 and 50, a rotation detecting device for detecting the rotation of the driven gears 39 and 40 is configured. The detailed structure and the rotation detection principle will be described later.

The annular driving gear 38 is rotatably supported by the annular peripheral wall 43, and is prevented from falling off by a retaining member 59. The retaining member 59 includes a fitting portion 60 fitted into the cutout portion 44 of the annular peripheral wall 43 and an outer peripheral flange portion 5 of the annular drive gear 38 as shown in an enlarged view in FIG.
3 and a pair of elastic blade pieces 62 which contact the outer peripheral wall 43 from outside and press the bearing 61 toward the inner surface of the annular peripheral wall 43. It is composed of The annular drive gear 38
As shown in FIG. 7, the support portion 61 abuts on the outer peripheral flange portion 53 to prevent the annular peripheral wall 43 from coming off.

FIGS. 4, 5, 8 to
As shown in FIG. 13, a connector portion 64 is provided, and the connector portion 64 is provided with a connector pin 65.
Connection holes 66 that are fitted into the connector pins 65 and are electrically connected to the connector pins 65 are formed in the circuit board 41 as shown in FIGS.

The outer and inner sides of the circuit board 41 are shown in FIG.
A small hole 67 for screw insertion is formed as shown in FIG.
A screw hole 68 is formed in the housing 37 at a location corresponding to the small hole 67. The housing 37 is provided with the tap screws 6 so as to cover the circuit board 41 from one side thereof.
9, the circuit board 41 and the housing 37 form a storage chamber 70 as shown in FIG.

The assembly of the steering angle sensor 35 is performed through the following procedure. First, the annular drive gear 38 is mounted on the housing 37 shown in FIG. 8 as shown in FIG. Next, the retaining member 59 is assembled to the annular peripheral wall 43 as shown in FIG. 10, and the driven gears 39 and 40 are attached as shown in FIGS.
While being engaged with the annular driving gear 38,
5 and 46 are rotatably supported. Next, as shown in FIG. 13, the circuit board 41 is put on the housing 37, and is fixed using tap screws 69 as shown in FIG. 3, and the connector pins 65 are soldered to the circuit board 41. Thus, the steering angle sensor 35 is assembled.

<Description of Detailed Structure of Rotation Detecting Apparatus>
The detailed structure and rotation detection principle of the rotation detection device according to the present invention will be described. The driven gears 39 and 40 have a circular fitting shaft portion 71 (see FIGS. 1 and 14) fitted to the circular bearing recesses 45 and 46 at one end surface (lower end surface) thereof, and are held at the other end surfaces. An annular contact portion 72 (see FIGS. 1 and 15) is formed so as to surround the holes 47 and 48. The annular contact portion 72 is in contact with one surface side of the circuit board 41 and surrounds the magnetoresistive elements 57 and 58 as shown in FIG.

The bottom surfaces of the holding holes 47 and 48 are formed from the upper surfaces of the disk-shaped magnets 49 and 50 so that
It functions as a positioning part that regulates the distance to the lower surface of the elements 7 and 58.

In the embodiment of the present invention, the holding holes 47,
Although the bottom surface of 48 is configured to serve as a positioning portion, the annular contact portion 72 is formed with an inner flange (not shown), and the inner flange has a role as a positioning portion. Holding holes 4 from the bottom side of gears 39 and 40
The disk-shaped magnets 49 and 50 are inserted into the driven gears 39 and 40 by inserting the disk-shaped magnets 49 and 50 into the driven gears 39 and 40 by inserting the disk-shaped magnets 49 and 50 into the inner flanges by a snap fastening member (not shown). It is good also as a structure which makes it hold | maintain.

As shown in FIG.
As shown in (a) and (b), for example, half-moon-shaped magnetic poles N and S are formed on the upper surface, and the symbol Φ1 indicates the direction of the magnetic flux. The disk-shaped magnets 49 and 50 are formed by injection molding, for example, by mixing a magnetic powder with a plastics molding resin at a predetermined ratio. In the embodiment of the present invention, the mixing ratio of (magnetic powder) :( plastics molding resin material) is 8: 2, and the mixing ratio can be appropriately changed according to use. These disc-shaped magnets 49, 50
Although it can be formed by sintering a magnetic material, it is desirable to use a plastic magnet from the viewpoint of resistance to cracking. In addition, as a material of the magnetic powder, for example, a neodymium alloy, a samarium-cobalt alloy, or the like is used.

The disc-shaped magnets 49 and 50 are shown in FIG.
As shown in FIG. 7, magnetizing is performed by applying a magnetic field from the upper surface side using a magnetizing device 75 including a horseshoe-shaped yoke 73 and an energizing coil 74, for example.

As schematically shown in FIG. 18A, in the disk-shaped magnet injection-molded products 49 'and 50', the magnetic moments of the magnetic powders are oriented in random directions before magnetization, and When a magnetic field is applied to the disk-shaped magnet injection molded products 49 ′, 50 ′ using the magnetic device 75, the magnetic moment of the magnetic powder on the upper surface side is more oriented along the direction of the magnetic field, and is directed toward the lower surface side. As a result, the number of magnetic moments arranged along the direction of the magnetic field decreases, whereby the number of magnetic fluxes Φ1 traveling from the N pole to the S pole on the upper surface side becomes smaller. More disk-shaped magnets 49 and 50 than the number are formed. Incidentally, the inventor of the present application was able to produce a disk-shaped magnet having only the magnetic flux Φ1 without the magnetic flux Φ2 by the magnetizing device 75.

The magnetic resistance of the magnetoresistive elements 57 and 58 varies depending on the number of magnetic fluxes (magnetic flux density) crossing the magnetoresistive elements 57 and 58. As shown in FIG. Disc-shaped magnet 4 in the direction of 0
With reference to the case where the magnetic fluxes of the magnetic fluxes 9 and 50 are oriented, when the disk-shaped magnets 49 and 50 rotate in the direction of the arrow to increase the number of magnetic fluxes Φ1 crossing the magnetoresistive elements 57 and 58, the magnetoresistance increases. When the disc-shaped magnets 49 and 50 are positioned in the direction of approximately 90 degrees as shown in FIG. 19B with respect to the position shown in FIG. The magnets 49 and 50 continue to rotate, and the position shown in FIG.
9 (c), when positioned in the 180-degree direction, the magnetic resistances of the magnetoresistive elements 57, 58 become minimum again. Therefore, according to this rotation detecting device, the magnetoresistive elements 57, 5
8 generates an AC analog electric signal AC (see FIG. 20) having two positive peaks due to a change in the direction of magnetic flux during one rotation of the disk-shaped magnets 49 and 50.

FIG. 20 shows the disc-shaped magnet 4
The output of the AC analog electric signal AC when the directions of the magnetic fluxes 9 and 50 are oriented at 45 degrees with reference to the position shown in FIG.

According to this rotation detecting device, the driven gear 3
A circular fitting shaft portion 71 formed on one end surface of each of the gears 9 and 40 is rotatably fitted into the circular bearing recesses 45 and 46, and an annular contact formed on the other end surface of each of the driven gears 39 and 40. Part 7
2 is brought into contact with the circuit board 41 and the driven gears 39 and 40 are rotated.
The driven gears 39 and 40 can be stably rotated even if they are only supported by the shaft. Further, the magnetoresistive elements 57, 5
8 is disposed at the center of rotation of the driven gears 39 and 40,
Rotation can be detected while avoiding vibrations and the like caused by the rotation of the rotator as much as possible, so that the rotation detection accuracy of the rotator is improved.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, as shown by broken lines in FIGS. 1 and 5, the annular groove 7 in which the annular contact portion 72 slides on one surface side of the circuit board 41.
2 'may be formed, and the upper end of the annular contact portion 72 may be slidably fitted in the annular groove 72'.

Further, as in the other embodiment shown in FIG. 21, the driven gears 39 and 40 are provided integrally with the rotating shaft 76, and the upper end surface and the lower end surface of the rotating shaft 76 are connected to the housings 37 and 3, respectively.
7 ′ is supported by the circular bearing recesses 77 and 78,
6, disk-shaped magnets 49, 50 are provided on the upper end surface, and the disk-shaped magnets 49, 50 are provided on the upper surface of the housing 37 '.
May be provided on the rotation center O1.

Further, in the embodiment of the present invention, the driven gears 39, 40 and the disk-shaped magnets 49, 50 are formed separately, but when the driven gears 39, 40 are formed, magnetic powder is mixed. The driven gears 39 and 40 can be magnetized to magnetize the driven gears 39 and 40 themselves. According to this configuration, the number of steps for assembling the disk-shaped magnets 49 and 50 can be reduced. The magnet is not limited to a disk.

[0046]

According to the rotation detecting device of the present invention, the rotation detecting element is disposed at the center of rotation of the rotating body. Therefore, the rotation detection accuracy of the rotating body is improved. In addition, since rotation can be detected with a reduced number of components, the rotation detection device as a whole can be made thinner, more compact, and lower in cost.

[Brief description of the drawings]

FIG. 1 is a partially enlarged view showing a state in which a steering angle sensor is incorporated in a storage recess formed on a lower surface of a lower cover member shown in FIG.

FIG. 2 is an explanatory view of an embodiment of the invention in which a rotation detecting device according to the present invention is applied to a steering angle sensor. FIG. 2 (a) shows a rotation connector device incorporating a steering angle sensor having a rotation detecting device. FIG. 2B is a schematic view showing a state where the rotary connector device shown in FIG. 1A is attached to a base member constituting a part of the combination switch.

FIG. 3 is a perspective view showing an entire configuration of a steering angle sensor.

FIG. 4 is an exploded perspective view of the steering angle sensor shown in FIG. 3 when viewed from a circuit board side.

5 is an exploded perspective view of the steering angle sensor shown in FIG. 3 turned upside down and viewed from a housing side.

FIG. 6 is an enlarged view of the retaining member shown in FIGS. 4 and 5;

FIG. 7 is an explanatory diagram for explaining a state in which the annular drive gear shown in FIGS. 4 and 5 is prevented from falling off by using a stopper member.

FIG. 8 is an explanatory view for explaining assembly of the steering angle sensor, and is a perspective view showing the housing before assembling the annular drive gear.

FIG. 9 is an explanatory view for explaining the assembly of the steering angle sensor, and is a perspective view showing a state where an annular drive gear is mounted on a housing.

FIG. 10 is an explanatory view for explaining the assembly of the steering angle sensor, and is a perspective view showing a state in which a retaining member is attached to a housing.

FIG. 11 is an explanatory view for explaining assembly of the steering angle sensor, and is a perspective view showing a state in which one driven gear is supported by one circular bearing recess.

FIG. 12 is an explanatory view for explaining the assembly of the steering angle sensor, and is a perspective view showing a state where the other driven gear is supported by the other circular bearing recess.

FIG. 13 is an explanatory diagram for explaining the assembly of the steering angle sensor, and is a perspective view showing a state in which a circuit board is covered on a housing.

FIG. 14 is an enlarged plan view showing a state where the driven gear shown in FIGS. 4 and 5 is viewed from below.

FIG. 15 is an enlarged plan view showing the driven gear shown in FIGS. 4 and 5 viewed from above.

16A and 16B are explanatory diagrams for explaining magnetic poles of the magnet shown in FIGS. 4 and 5, wherein FIG. 16A is a plan view and FIG. 16B is a side view.

FIG. 17 is an explanatory diagram for explaining magnetization of a magnet.

18A and 18B are schematic diagrams for explaining a magnetized state of a magnet, wherein FIG. 18A shows a state of a magnetic moment before magnetization, and FIG. 18B shows a state of a magnetic moment after magnetization.

FIGS. 19A and 19B are schematic diagrams for explaining the principle of rotation detection of a rotating body by the rotation detection device according to the present invention, wherein FIG. ) Shows a state in which the direction of the magnetic flux changes by 90 degrees with respect to the direction of the magnetic flux shown in (a), and (c) shows a state in which the direction of the magnetic flux changes by 180 degrees with respect to the direction of the magnetic flux shown in (a). Show.

FIG. 20 is a diagram showing an analog electric signal generated based on rotation of a magnet.

FIG. 21 is a schematic view showing another example of the rotation detecting device according to the present invention.

FIGS. 22A and 22B are explanatory views for explaining a main part configuration of a conventional rotation detecting device, wherein FIG. 22A is a cross-sectional view of the main part of the rotation detecting device, and FIG. Fig. 3 shows a plan view of the plate, and (c) shows a pulse-like signal generated by the rotation detecting device.

[Explanation of symbols]

 37 housing 39, 40 driven gear (disk-like rotating body) 41 circuit board 45, 46 circular bearing recess 57, 58 magnetoresistive element (rotation detecting element) 71 circular fitting shaft part 72 annular contact part O1 rotation center

Claims (5)

[Claims] 1. A circular bearing recess is formed in a housing on which a circuit board is mounted and in which a disk-shaped rotating body is housed in cooperation with the circuit board, and the circular-shaped rotating body is formed on one end surface of the disk-shaped rotating body. A circular fitting shaft portion that is fitted into the bearing recess and rotatably supported is formed, and an annular abutting portion that abuts on the circuit board is provided on the other end surface of the disk-shaped rotating body. A rotation detecting element for detecting the rotation of the disc-shaped rotator is provided on the circuit board on the rotation center on one side facing the disc-shaped rotator, and the rotation contact element is surrounded by the annular contact portion. A rotation detecting device, wherein the rotation detecting device is fixed in such a manner as to be fixed. 2. The rotation detecting element according to claim 1, wherein the rotation detecting element is a magnetic change detecting element that detects a change in magnetic flux accompanying rotation of the disc-shaped rotator, and the disc-shaped rotator is provided at a rotation center portion thereof. A rotation detecting device provided with a magnet. 3. The method according to claim 2, wherein the magnet is
The magnetic change detecting element has an N pole and an S pole on one side facing the magnetic change detecting element, and the magnetic change detecting element has an analog electric element whose magnetic resistance changes based on a change in the direction of a magnetic flux accompanying rotation of the disk-shaped rotator. A rotation detecting device, which is a magnetoresistive element that generates a signal. 4. A steering gear according to claim 3, wherein said disk-shaped rotating body is a driven gear meshed with and driven by an annular drive gear forming a part of a steering angle sensor. A rotation detection device characterized by being rotated with rotation. 5. A magnet is provided at the center of rotation of the rotator, the magnet has an N pole and an S pole on one surface side, and the magnet is provided on the center of rotation to detect the rotation of the rotator. A rotation detecting device, comprising: a magnetoresistive element that generates an analog electric signal by changing a resistance based on a change in a direction of a magnetic flux accompanying rotation of a rotating body.