JP2002131090A - Rotary angle detector, torque detector and steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary angle detector improving durability without including a contacting and sliding part, a torque detector detecting rotary torque using it and a steering device provided with them. SOLUTION: Ring-like targets 2 are fixed on the lower end of an input shaft 31 and the upper end of an output shaft 32 respectively. The reflection part 20 of a saw-toothed groove is circumferentially provided on the outer peripheral face of the target 2, and the bottom face of the reflection part 20 is made a mirror face so that a mirror face reflectance is high as compared with the other face. Line sensors 1A, 1B long in the axial length direction of a steering shaft 3 are arranged on the outside of the targets 2, 2, their outputs VA, VB are given to a calculation processing part 4, and the rotary angles of the input shaft 31 and the output shaft 32 and the rotary torque applied on the input shaft 31 are calculated in the calculation processing part 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation angle detecting device for detecting a rotation angle of a rotating shaft, a torque detecting device for detecting a rotating torque applied to the rotating shaft, and a steering device for an automobile provided with these devices.

[0002]

2. Description of the Related Art There is a steering apparatus for a vehicle that assists steering by driving an electric motor to reduce a burden on a driver. It comprises an input shaft connected to a steered wheel (steering wheel), an output shaft connected to a steered wheel by a pinion and a rack, and a connection shaft connecting the input shaft and the output shaft. A torque detection device detects a steering torque applied to an input shaft, and drives and controls an electric motor for steering assistance linked to an output shaft based on the steering torque detected by the torque detection device. Further, such a steering device obtains a steering angle midpoint of a steered wheel by a rotation angle detecting device, and also performs drive control of an electric motor according to the steered angle of the steered wheel.

[0003]

However, the conventional steering apparatus as described above includes a contact sliding part such as a potentiometer, and there is a possibility that a failure or deterioration in performance due to wear or aging may occur. There was a problem in durability. Further, the torque detecting device detects a change in impedance of the magnetic circuit caused by the torsion of the connecting shaft, and has a problem that the configuration is complicated and the manufacturing cost is high.

[0004] The present invention has been made in view of such circumstances, and provides a target having a reflecting portion provided around a rotating shaft, a light receiving portion opposed to the target, and as the rotating shaft rotates. By configuring the target such that the portion of the reflecting portion facing the light receiving portion changes periodically and continuously in the axial direction of the rotation axis,
It does not include a part that slides in contact with the rotation of the rotating shaft, and enables the light receiving unit to determine the rotation angle of the rotating shaft from an output generated in response to the passage of the reflecting unit facing the light receiving unit. It is an object to provide a rotation angle detection device, a torque detection device that detects a rotation torque applied to a rotation shaft using the rotation angle detection device, and a steering device including the same.

Another object of the present invention is to provide a target on a rotating shaft, provide a light receiving portion facing the target, and position the surface of a portion of the target facing the light receiving portion as the rotating shaft rotates. However, by configuring the target so as to change periodically and continuously, the target does not include a portion that slides in contact with the rotation of the rotating shaft, and the light-receiving unit can pass through the surface of the target opposed thereto. A rotation angle detection device that enables the rotation angle of the rotation shaft to be obtained from an output generated in response thereto, a torque detection device that detects a rotation torque applied to the rotation shaft by using the rotation angle detection device, and a steering device including the same. The purpose is to provide.

[0006]

According to a first aspect of the present invention, there is provided a rotation angle detecting device for detecting a rotation angle of a rotation shaft, wherein the detected position is periodically and periodically detected as the rotation shaft rotates. A target having a reflection portion provided along the circumferential direction of the rotation axis so as to be continuously changed, and a target disposed opposite to the target, receiving reflected light from the opposing target, and performing the reflection based on the received light. A light receiving unit for detecting the position of the unit, wherein the rotation angle of the rotating shaft is obtained based on the position of the reflecting unit detected by the light receiving unit.

[0007] In the case of the rotation angle detecting device according to the first aspect of the present invention, a target having a reflecting portion provided around the rotating shaft is provided.
Providing a light receiving unit facing the target, and configuring the target such that the position of the reflecting unit facing the light receiving unit changes periodically and continuously as the rotation axis rotates, thereby achieving a target. Since the position of the reflection unit is detected by the light receiving unit arranged at a position separated from, it does not include a part that slides in contact with the rotation of the rotating shaft,
The rotation angle of the rotating shaft can be obtained from the position of the reflection unit opposed to the light detection unit detected by the light reception unit.

According to a second aspect of the present invention, in the rotation angle detecting device for detecting the rotation angle of the rotation shaft, the detected surface position periodically and continuously changes as the rotation shaft rotates. A target having such a surface shape, and a light receiving unit that is disposed to face the target, receives reflected light from the facing target, and detects a surface position of the target based on the received light, and the light receiving unit detects the light. The rotation angle of the rotation shaft is obtained based on the surface position of the target.

In the case of the rotation angle detecting device according to the second aspect of the present invention, a target is provided on the rotating shaft, and a light receiving portion facing the target is provided. As the rotating shaft rotates, the target faces the light receiving portion of the target. The surface position of the part is
By configuring the target to change periodically and continuously, the surface position of the target is detected by the light receiving unit arranged at a position separated from the target. The rotation angle of the rotation shaft can be obtained from the surface position of the target facing the light detection unit detected by the light receiving unit, not including the portion where the rotation occurs.

[0010] The torque detecting device according to the third invention is provided with the rotation angle detecting device according to the first or second invention at two locations separated from each other in the axial direction of the rotating shaft. The rotation torque applied to the rotation shaft is obtained based on a difference between the detected rotation angles.

In the case of the torque detecting device according to the third aspect of the present invention, the targets are provided at two positions in the axial direction of the rotating shaft, and the light receiving sections are arranged outside each of them, and based on the detection results of these light receiving sections. The rotation torque is determined based on the difference between the rotation angles determined for each. Therefore, it does not include a portion that slides in contact, and it is possible to improve the durability of the device as compared with the related art.

A torque detecting device according to a fourth aspect of the present invention is the torque detecting device according to the third aspect of the present invention, wherein the rotating shaft comprises a first shaft and a second shaft connected coaxially through a torsion bar.
It is a connected body of shafts, wherein the targets are arranged near the connecting portions of the first shaft and the second shaft, respectively.

[0013] In the case of the torque detecting device according to the fourth aspect of the present invention, targets are provided on the first axis and the second axis which are coaxially connected via a torsion bar, and the light receiving sections are disposed outside each of the targets. Then, a difference in rotation angle between the first axis and the second axis caused by torsion of the torsion bar is determined by using the detection result of the light receiving unit, and the first axis and the second axis are determined using the result. The rotational torque applied to the motor is detected.

According to a fifth aspect of the present invention, there is provided a steering device according to the first or second aspect, wherein a steering shaft for connecting a steering wheel and a steering mechanism is used as the rotation axis. (4) It is characterized by including one or both of the torque detecting devices according to the invention.

In the case of the steering device according to the fifth invention, one of the rotation angle detection device according to the first or second invention and the torque detection device according to the third or fourth invention that does not include a portion that slides in contact. Alternatively, both are applied to a steering device of an automobile, and a rotation angle (steering angle) of a steering shaft and a detection value of a rotation torque (steering torque) applied to the steering shaft are obtained, and these results are used for steering assist. Used for various controls such as motor drive control.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. (Embodiment 1) FIG. 1 is a schematic diagram showing a configuration of a main part of Embodiment 1 of a steering device according to the present invention. As shown in the figure, an input shaft 31 whose upper end is connected to a steering wheel (steering wheel) 30 and an output shaft 32 whose lower end is connected to a pinion 33 of a steering mechanism are connected to a small-diameter torsion bar 34.
And a steering shaft 3 for connecting the steering wheel 30 and a steering mechanism coaxially with each other.

The input shaft 31 has a coaxial annular target 2 having a reflection portion 20 in the vicinity of a connection side with the output shaft 32 and having a circumferentially bent groove-like shape. Fixed. The target 2 has a bottom with a high specular reflectance at the bottom of the reflector 20 so that most of the light applied to the surface is irregularly reflected and most of the light applied to the reflector 20 is specularly reflected. The surface of the other target 2 is made rougher than the bottom of the reflecting section 20 so as to have a lower mirror reflectance than the bottom. Similarly, the output shaft 32 is provided with the target 2 near the end on the connection side with the input shaft 31.

As described above, since the reflecting portion 20 is bent in a saw-tooth shape, the reflecting portion 20 has a plurality of portions inclined at a predetermined angle with respect to the longitudinal direction of the steering shaft 3. The shape is such that the position of the steering shaft 3 in the axial length direction rises linearly in the direction of a in the figure.

In the first embodiment, the target 2 has the groove-shaped reflecting portion 20. However, the present invention is not limited to this. For example, the reflecting tape may be adhered to the surface of the target 2 by applying a reflecting tape. It is needless to say that the configuration may be such that the surface of the target 2 is not provided with projections and depressions, or that the reflecting portion 20 protrudes from the surface of the target 2.

Outside such targets 2 and 2,
Two sensor boxes 1a are arranged at two different positions in the circumferential direction of the steering shaft 3 so as to face the outer edges of the targets 2 and 2, respectively. The sensor box 1a is fixedly supported by a stationary part such as a housing that supports the input shaft 31 and the output shaft 32.

An input shaft 3 is provided inside the sensor box 1a.
A line sensor 1A facing the target 2 on the output shaft 32 and a line sensor 1B facing the target 2 on the output shaft 32
Are accommodated in the same position in the circumferential direction.

Each of the line sensors 1A and 1B has a plurality of light receiving elements arranged in parallel in the axial direction of the steering shaft 3. Inside the sensor box 1a, a rod-shaped light emitting portion 11A is arranged in parallel with the line sensor 1A, and a light emitting portion 11B is arranged in parallel with the line sensor 1B. The light receiving surfaces of the line sensors 1A and 1B are
The light emitted from the light emitting units 11A and 11B is directed so as to be able to receive specularly reflected light from the surfaces of the targets 2 and 2.

Each of the line sensors 1A and 1B is a sensor using a light receiving element such as a CCD which generates an output in accordance with the amount of received light, and outputs _VA and V of the line sensors 1A and 1B.
_B is drawn out of the sensor box 1a and provided to an arithmetic processing unit 4 using a microprocessor.

FIG. 2 is a graph showing the output _VA of the line sensor 1A. In the figure, the vertical axis indicates the output, and the horizontal axis indicates the position of the light receiving element included in the line sensor 1A in the axial direction of the steering shaft 3. As shown, the output V _A
Includes the output of each of the plurality of light receiving elements. The light receiving element facing the reflection unit 20 receives the specularly reflected light from the reflection unit 20, and the output of this light reception element is higher than that of the other light reception elements. The arithmetic processing unit 4 includes:
As described above, the threshold th that is smaller than the output of the light receiving element facing the reflection unit 20 and larger than the output of the other light receiving elements is given in advance, and the arithmetic processing unit 4 calculates the output of each light receiving element and the threshold th. By comparison, it is determined that a light receiving element having an output exceeding the threshold th is opposed to the reflecting section 20. Also, as shown in FIG. 2, when the outputs of a plurality of adjacent light receiving elements exceed the threshold th, it is determined that the light receiving element located at an intermediate position among them faces the reflecting section 20. ing. Also, the description thereof is omitted since it is same for the output V _B of the line sensor 1B.

Accordingly, the light receiving element facing the reflecting section 20 is detected by the processing in the arithmetic processing section 4, and the steering shaft 3 of the reflecting section 20 is determined based on the position of the light receiving element.
Is detected in the axial direction.

FIG. 3 is an explanatory diagram for explaining the relationship between the position of the reflector 20 in the axial direction of the steering shaft 3 and the rotation angle of the input shaft 31 or the output shaft 32. As described above, the reflector 20 has a saw-tooth shape, and a portion of the reflector 20 inclined with respect to the axial direction of the steering shaft 3 (hereinafter, referred to as a first portion) is defined with respect to the axial direction. They are juxtaposed with a predetermined inclination angle. Therefore, when the input shaft 31 and the output shaft 32 rotate around the axes, the line sensors 1A, 1
The position of the portion facing B in the axial direction is one first position.
It changes linearly between the sections according to the change in the rotation angle of the input shaft 31 or the output shaft 32. In addition, a portion having the axial length direction connecting two adjacent first portions as a longitudinal direction (hereinafter, referred to as a second portion)
When the line sensors 1A and 1B face each other, the position of the central portion of the second portion is determined to be the position facing the light receiving element.

The target 2 is provided with a reflector 20 around which the specular reflectivity of the target 2 is higher than the specular reflectivity of the other surface, and the threshold th of the light receiving elements of the line sensors 1A and 1B is set. The light receiving element having a larger output is
Has been described above, but the present invention is not limited to this. For example, a groove having the same shape as that of the reflection section 20 is provided on the outer periphery of the target 2 so that the target 2 The surface other than the groove is a reflection part,
Towards the specular reflectance of the groove is set to be lower than the specular reflectance of the reflection portion, the line sensor 1A, the output V _A of 1B, from V _B, the line sensors 1A, among the light receiving elements 1B, the threshold The light receiving element having an output smaller than th may be determined as the light receiving element facing the groove.

As a result, as shown in FIG. 3, the positions of the reflecting portions 20, 20 in the direction of the axis length of the steering shaft 3 detected by the line sensors 1A, 1B are line sensors 1A, 1B.
(First area) that changes linearly according to the rotation of the input shaft 31 or the output shaft 32 while each first part passes near
And a region (second region) that changes in the opposite direction to the change in the first region while each second part passes near the line sensors 1A and 1B. The period of this repetition corresponds to the number of the first portion and the second portion of the reflecting portion 20 of the target 2 arranged in parallel, and 8
When the first and second parts are arranged side by side, repetition occurs in which one cycle is a period during which the input shaft 31 or the output shaft 32 rotates by 45 ° (= 360 ° / 8).

Output V of line sensor 1A_ADetected from
The position of the reflector 20 in the axial direction of the steering shaft 3 is
Input shaft provided with a reflection unit 20 facing the sensor 1A
31 and the output V of the line sensor 1B.
_BPosition of the reflector 20 in the axial direction of the steering shaft 3 detected from the
The reflection unit 20 facing the line sensor 1B is provided.
Corresponding to the rotation angle of the output shaft 32. Therefore,
Output V of the sensor 1A _ARotation angle of the input shaft 31 based on
Is the output V of the line sensor 1B._BOutput shaft 32 based on
Can be separately calculated.

The arithmetic processing section 4 is provided with a storage section comprising a semiconductor memory (not shown). The storage section stores the position of the detected reflection section 20 in the axial direction of the steering shaft 3 and the detected position. , The correspondence relationship with the rotation angle of the target 2 is mapped for one cycle of the above-described repetition. The arithmetic processing unit 4 counts how many cycles the repetition has passed, and refers to the contents of the storage unit to detect the 1st target 2 corresponding to the detected position of the reflection unit 20 in the axial direction. The rotation angle within the cycle is obtained, and the sum of the product of the counting result and the rotation angle for one cycle (45 ° in the case shown in FIG. 2) and the rotation angle within the one cycle is calculated, and the input shaft is calculated. The rotation angle of the output shaft 31 or the output shaft 32 is calculated.

Further, a difference (relative angular displacement) between the obtained rotation angle of the input shaft 31 and the rotation angle of the output shaft 32 is obtained, and the difference between the relative angular displacement and the rotation torque stored in the storage unit in advance is obtained. From the relationship, the rotational torque applied to the input shaft 31 is determined.

The rotation angle of the output shaft 32 and the rotation torque applied to the input shaft 31 thus obtained are given to a control unit (not shown).
An electric motor (not shown) connected to the motor is driven and controlled, thereby assisting the steering.

In the first embodiment, the reflecting portion 20 has a saw-tooth shape. However, the present invention is not limited to this. For example, the reflecting portion 20 may have a predetermined shape in the axial direction of the steering shaft 3. The configuration may include only a plurality of grooves inclined at an angle, or the configuration may be such that the reflection unit 20 has a sinusoidal shape.

In the first embodiment, the input shaft (first shaft) 31 connected through the torsion bar 34 is used.
Although the configuration in which the targets 2 and 2 are provided on the output shaft (second shaft) 32 and the output shaft (second shaft) 32 has been described, when the target is a rotary shaft whose torsion characteristic is clear, the target is separated in the axial direction of the rotary shaft. The targets 2 and 2 may be provided directly at the positions thus set, and the rotational torque may be calculated based on the outputs of the line sensors disposed to face each other.

With the above configuration, the input shaft 31 and the output shaft are not included in the input sensor 31 according to the output generated when the line sensors 1A and 1B pass through the reflecting portions 20 and 20 facing the same without including the portions that contact and slide. Rotation angle of shaft 32 and input shaft 3
1 can be obtained.

(Embodiment 2) FIG. 4 is a schematic diagram showing a configuration of a main part of a steering apparatus according to Embodiment 2 of the present invention. As shown in the drawing, a ring-shaped target 2 is coaxially fixed to the input shaft 31 near the end on the connection side with the output shaft 32. Similarly, the output shaft 32 includes
The target 2 is coaxially fixed near the end on the connection side with the input shaft 31. On an upper surface of the target 2 on the input shaft 31 side and a lower surface of the target 2 on the output shaft 32 side, a reflecting portion 20 as described later is provided.

The reflecting portion 20 moves in the direction of a in FIG.
A plurality of portions (hereinafter, referred to as “first portions”) that are linearly distant from the axis of the steering shaft 3 are connected to the ends of the adjacent two first portions on the periphery of the steering shaft 3. Are provided along the circumferential direction of the steering shaft 3 in a state where the positions of the steering shafts 3 are aligned with each other. Linear part (hereinafter, referred to as
(Referred to as a second part).

A sensor box 1a having a substantially U-shape in side view.
Are disposed near the targets 2 and 2 so that a part of the targets 2 and 2 is located inside the U-shape.
The light receiving surface of the line sensor 1A is exposed on the upper surface of the two opposing surfaces inside the U shape of the sensor box 1a,
The line sensors 1A and 1B are arranged such that the light receiving surface of the line sensor 1B is exposed on the lower surface. The line sensors 1A and 1B pass through the inside of the sensor box 1a with the radial direction of the steering shaft 3 as the longitudinal direction, and are located near the line sensors 1A and 1B inside the sensor box 1a, respectively. So that it is parallel to
Bar-shaped light emitting units 11A and 11B are provided.

FIG. 5 is an explanatory diagram for explaining the relationship between the radial position of the steering shaft 3 of the reflector 20 and the rotation angle of the input shaft 31 or the output shaft 32. As shown in FIG. 5, the positions of the reflectors 20 and 20 in the radial direction of the steering shaft 3 detected by the line sensors 1A and 1B are as shown in FIG.
A region (first region) that changes linearly according to the rotation of the input shaft 31 or the output shaft 32 while each of the first portions passes near B, and a second portion around the line sensors 1A and 1B. Shows a change that repeats a region (a second region) that changes in the opposite direction to the change of the first region during the passage of. The cycle of this repetition corresponds to the number of the first portions of the reflection portions 20 of the target 2. When the eight reflection portions 20 of the target 2 are provided, the input shaft 31 or the output shaft 32
Is rotated by 45 ° (= 360 ° / 8) as one cycle.

In the second embodiment, as described above, the reflecting portion 20 includes the first portion in which the distance from the axis of the steering shaft 3 linearly increases toward the direction a in FIG. , And a second part that connects adjacent first parts, but the present invention is not limited to this.
0 may have only the first portion, and may not have the second portion. The reflecting portion 20 may be arranged such that the distance from the axis of the steering shaft 3 in the direction of a is sinusoidal. It is good also as a structure which forms the shape which increases and decreases in a school form. Embodiment 2
The other configuration of the steering device according to the first embodiment is the same as the configuration of the steering device according to the first embodiment, and a description thereof will be omitted.

With the above-described configuration, the input shaft 31 and the output shaft are not included in the input shaft 31 and the output according to the output generated by the line sensors 1A and 1B passing through the reflecting portions 20 and 20 facing the line sensors 1A and 1B. Rotation angle of shaft 32 and input shaft 3
1 can be obtained.

(Embodiment 3) FIG. 6 is a schematic diagram showing a configuration of a main part of a steering apparatus according to Embodiment 3 of the present invention. As shown in the figure, an annular plate-shaped target 2a is coaxially fixed to the input shaft 31 near the end on the connection side with the output shaft 32. The target 2 b is coaxially fixed to the output shaft 32 near the end on the connection side with the input shaft 31. In the target 2b, an annular ring having an inner diameter larger than the outer diameter of the target 2a has the same outer diameter as the annular ring, and protrudes from an upper surface of an annular plate fixed coaxially to the output shaft 32. The targets 2a and 2b are arranged such that the upper surface of the target 2a and the upper surface of the ring of the target 2b are located on the same plane.

A groove-shaped reflecting portion 20a is provided around the upper surface of the target 2a, and a groove-shaped reflecting portion 20b is also provided on the upper surface of the ring of the target 2b.

A plurality of portions (hereinafter, referred to as first portions) of the reflecting portions 20a and 20b which are linearly distant from the axis of the steering shaft 3 in the direction of a in FIG. The two first portions adjacent to each other are provided along the circumferential direction of the steering shaft 3 with the ends of the two first portions that are close to each other being aligned in the circumferential direction of the steering shaft 3. Is a groove having a shape as if the end portions on the side closer to each other were connected by a linear portion (hereinafter referred to as a second portion) whose longitudinal direction is the radial direction of the steering shaft 3.

A sensor box 1a is provided above the targets 2a and 2b, and a line sensor 1A is provided inside the sensor box 1a and at a position facing the reflection section 20a. A line sensor 1B is provided inside the sensor box 1a and at a position facing the reflection section 20b. The line sensors 1A and 1B are arranged such that their light receiving surfaces are exposed on the lower surface of the sensor box 1a. The line sensors 1A and 1B each have a sensor box 1a with the radial direction of the steering shaft 3 as a longitudinal direction. Has been passed inside. Then, the line sensor 1A inside the sensor box 1a,
In the vicinity of 1B, bar-shaped light emitting units 11A and 11B are provided so as to be parallel to the line sensors 1A and 1B, respectively.

The relationship between the radial position of the steering shaft 3 of the reflecting portions 20a and 20b detected by the line sensors 1A and 1B, respectively, and the rotation angle of the input shaft 31 or the output shaft 32 is as follows.
The relationship between the reflection unit 20 and the rotation angle of the input shaft 31 or the output shaft 32 shown in FIG.

In the third embodiment, as described above, the reflecting portions 20a and 20b are arranged so that the distance from the axis of the steering shaft 3 increases linearly toward the direction a in the figure. Although the configuration including the first portion and the second portion connecting the adjacent first portions has been described, the present invention is not limited to this. For example, the reflection portions 20a and 20b include only the first portion and the second portion. It is good also as composition which does not have the section, reflection section 2
0a and 20b may be configured to have a shape in which the distance from the axis of the steering shaft 3 increases and decreases in a sine-shape manner in the direction of a. Further, the other configuration of the steering device according to the third embodiment is the same as the configuration of the steering device according to the first embodiment, and a description thereof will be omitted.

With the above configuration, a portion that slides in contact is provided.
, Line sensors 1A and 1B are opposed to these.
Output generated in response to passage through reflection units 20a and 20b
V_A, V _BDepending on the rotation of the input shaft 31 and the output shaft 32
The angle and the rotational torque applied to the input shaft 31 can be determined.
it can.

(Embodiment 4) FIG. 7 is a schematic diagram showing a configuration of a main part of a steering apparatus according to Embodiment 4 of the present invention. As shown in the drawing, a target 2 having a shape to be described later is coaxially fixed to the input shaft 31 in the vicinity of an end on the connection side with the output shaft 32. Similarly, the target 2 is coaxially fixed to the output shaft 31 near the end on the connection side with the input shaft 31.

The target 2 has a substantially annular plate shape in which a plurality of protrusions are arranged side by side on the outer periphery, and each protrusion has a surface position of the steering shaft 3 in the direction of a in the figure. The surface shape is linearly far from the axis. The two adjacent projections are connected by a plane whose normal direction is the circumferential direction of the steering shaft 3.

A sensor box 1a is disposed at a position facing the outer edges of the targets 2 and 2. An optical distance sensor 5A facing the target 2 on the input shaft 31 side is provided inside the sensor box 1a. An optical distance sensor 5B facing the target 2 on the output shaft 32 side is provided. Each of the optical distance sensors 5A and 5B includes a light emitting element and a light receiving element. Light emitted from the light emitting element is reflected by the surface of the target 2 and is received by the light receiving element. And outputs that change in proportion to the distance between the optical distance sensors 5A and 5B and the surfaces of the targets 2 and 2.

FIG. 8 shows the output of the optical distance sensors 5A and 5B.
Force V_A, V_BAnd the rotation angle of the input shaft 31 or the output shaft 32
4 is a graph for explaining the relationship. In the figure, the vertical axis is
The magnitude of the force is shown, and the horizontal axis shows the rotation angle. Mentioned earlier
As described above, the light is emitted from the optical distance sensors 5A and 5B.
Output V_A, V_BAre optical distance sensors 5A and 5B and
Because it changes in proportion to the distance from the surface of Get 2, 2,
Optical distance sensors 5A and 5B face one protrusion
In the position, the input shaft 31 or the output shaft is moved in the direction of arrow a shown in FIG.
When the force shaft 32 rotates, the optical distance sensor 5A or 5A
Output V of B_AOr V_BWill increase linearly. So
To reach the end of the protrusion, and the adjacent protrusion
When facing the optical distance sensors 5A and 5B, the output
V_A, V _BDecreases, and furthermore, the input shaft 31 or the output shaft 32
As it rotates, the output V as described above_AOr V_Bof
The increase is repeated. The cycle of this repetition depends on the target
8 projections on the target 2 corresponding to the number of projections on the target 2
When the unit is provided, the input shaft 31 or the output shaft 3
One cycle while 2 rotates by 45 ° (= 360 ° / 8)
Is repeated.

The output V _A of the optical distance sensor 5A corresponds to the rotation angle of the input shaft 31 provided with the target 2 facing the optical distance sensor 5A, and the output V _B of the optical distance sensor 5B is This optical distance sensor 5B corresponds to the rotation angle of the output shaft 32 provided with the target 2 facing the optical distance sensor 5B. Therefore, it is possible to calculate the rotation angle of the input shaft 31 based on the output V _A of the distance sensors 5A, the rotation angle of the output shaft 32 to each other on the basis of the output V _B of the distance sensors 5B.

[0054] The arithmetic processing unit 4 (not shown) storage unit is provided comprising a semiconductor memory, in the storage unit, optical distance sensors 5A, 5B output V _A of the V _B,
The correspondence relationship with the rotation angle of the target 2 is mapped for one cycle of the above-described repetition. The arithmetic processing unit 4 is configured to count whether the repetition has passed many cycles, with reference to the contents of the storage unit, the output V _A, the rotation angle of the one cycle of the target 2 which corresponds to the V _B The counting result and the rotation angle for one cycle (45 in the case shown in FIG. 8)
°) and the rotation angle in one cycle are calculated to calculate the rotation angle of the input shaft 31 or the output shaft 32.

Further, a difference (relative angular displacement) between the obtained rotation angle of the input shaft 31 and the rotation angle of the output shaft 32 is obtained, and the difference between the relative angular displacement and the rotation torque stored in the storage unit in advance is obtained. From the relationship, the rotational torque applied to the input shaft 31 is determined.

In the fourth embodiment, the outer periphery of the target 2 moves in the direction of a in FIG.
A configuration having a plurality of protrusions whose distance from the axis of the target increases linearly has been described. However, the present invention is not limited to this. For example, when the outer peripheral portion of the target 2 moves in the direction of a, the steering shaft 3 May be configured to have a surface shape in which the distance from the axis center increases or decreases sinusoidally. Further, the other configuration of the steering device according to the fourth embodiment is the same as the configuration of the steering device according to the first embodiment, and a description thereof will be omitted.

With the above configuration, a portion that slides in contact is provided.
Are not included, and the optical distance sensors 5A and 5B are opposed to these.
Generated in response to the passage of targets 2 and 2
V_A, V _BDepending on the rotation of the input shaft 31 and the output shaft 32
The angle and the rotational torque applied to the input shaft 31 can be determined.
it can.

(Embodiment 5) FIG. 9 is a schematic diagram showing a configuration of a main part of a steering apparatus according to Embodiment 5 of the present invention. As shown in the drawing, a ring-shaped target 2 is coaxially fixed to the input shaft 31 near the end on the connection side with the output shaft 32. Similarly, the output shaft 32 includes
The target 2 is coaxially fixed near the end on the connection side with the input shaft 31. The upper surface of the target 2 on the input shaft 31 side and the lower surface of the target 2 on the output shaft 32 have surface shapes as described later.

The outer peripheral edge of each of the upper surface of the target 2 on the input shaft 31 side and the lower surface of the target 2 on the output shaft 32 has a surface shape such that a plurality of protruding portions projecting in a sawtooth shape are provided. . The respective projecting portions of the target 2 on the input shaft 31 side are such that the surface position in the axial direction of the steering shaft 3 rises linearly in the direction of a in the figure, and the target on the output shaft 32 side. Each of the projections 2 is configured such that the surface position in the axial direction linearly decreases toward the direction a. The two adjacent projections are connected by a plane whose normal direction is the circumferential direction of the steering shaft 3.

Further, a sensor box 1a having a substantially U-shape in side view is arranged near the targets 2, 2 so that a part of the targets 2, 2 is located inside the U-shape. The light receiving surface of the optical distance sensor 5A is exposed on the upper surface and the light receiving surface of the optical distance sensor 5B is exposed on the lower surface of the two opposing surfaces inside the U shape of the sensor box 1a. As described above, the optical distance sensors 5A and 5B are provided.

The outputs V _{A of} the optical distance sensors 5A and 5B,
And V _B, the relationship between the rotation angle of the input shaft 31 or output shaft 32 is the same as the relationship shown in FIG. 8, a description thereof will be omitted.

In the fifth embodiment, the upper surface of the target 2 on the input shaft 31 and the lower surface of the target 2 on the output shaft 32 move from the axis of the steering shaft 3 in the direction of a in FIG. Has been described as having a plurality of protrusions whose distance increases linearly, but is not limited thereto. For example, the upper surface of the target 2 on the input shaft 31 side and the output shaft 32
The lower surface of the target 2 on the side is directed in the direction of a,
The steering shaft 3 may be configured to have a surface shape in which the surface position in the axial direction rises and falls in a sinusoidal manner. Further, the other configuration of the steering device according to the fifth embodiment is the same as the configuration of the steering device according to the fourth embodiment, and a description thereof will be omitted.

With the above configuration, the contact sliding portion
Are not included, and the optical distance sensors 5A and 5B are opposed to these.
Generated in response to the passage of targets 2 and 2
V_A, V _BDepending on the rotation of the input shaft 31 and the output shaft 32
The angle and the rotational torque applied to the input shaft 31 can be determined.
it can.

(Embodiment 6) FIG. 10 is a schematic diagram showing a configuration of a main part of a steering apparatus according to Embodiment 6 of the present invention. As shown in the figure, an annular plate-shaped target 2a is coaxially fixed to the input shaft 31 near the end on the connection side with the output shaft 32. The target 2 b is coaxially fixed to the output shaft 32 near the end on the connection side with the input shaft 31. In the target 2b, an annular ring having an inner diameter larger than the outer diameter of the target 2a has the same outer diameter as the annular ring, and protrudes from an upper surface of an annular plate fixed coaxially to the output shaft 32. The targets 2a and 2b are arranged in a state where the target 2a is fitted inside the ring of the target 2b.

The outer peripheral edge of the upper surface of the target 2a and the upper surface of the ring of the target 2b have a surface shape such that a plurality of protruding portions projecting in a saw-tooth shape are respectively provided.
Each protruding portion is configured so that the surface position of the steering shaft 3 in the axial length direction linearly increases in the direction of a in the drawing. The two adjacent projections are connected by a plane whose normal direction is the circumferential direction of the steering shaft 3.

A sensor box 1a is provided above the targets 2a and 2b. An optical distance is set inside the sensor box 1a and at a position facing the upper edge of the target 2a. A sensor 5A is provided, and an optical distance sensor 5B is provided inside the sensor box 1a at a position facing the upper surface of the ring of the target 2b. The optical distance sensors 5A and 5B are arranged such that their light receiving surfaces are exposed on the lower surface of the sensor box 1a.

The outputs V _{A of} the optical distance sensors 5A and 5B,
And V _B, the relationship between the rotation angle of the input shaft 31 or output shaft 32 is the same as the relationship shown in FIG. 8, a description thereof will be omitted.

In the sixth embodiment, the upper surface of the target 2a and the upper surface of the ring of the target 2b have a linearly increasing distance from the axis of the steering shaft 3 toward the direction a in the figure. However, the present invention is not limited to this. For example, the upper surface of the target 2a and the upper surface of the ring of the target 2b may be
A configuration may be adopted in which the surface position of the steering shaft 3 in the axial center direction rises and falls in a sinusoidal manner in the direction a. Further, the other configuration of the steering device according to the sixth embodiment is the same as the configuration of the steering device according to the fourth embodiment, and a description thereof will be omitted.

With the above-described configuration, the optical distance sensors 5A and 5B do not include the parts that make contact and slide, and correspond to the outputs V _A and V _B generated by the passage of the targets 2a and 2b opposed thereto. , The rotation angles of the input shaft 31 and the output shaft 32 and the rotational torque applied to the input shaft 31 can be obtained.

[0070]

As described above in detail, in the case of the rotation angle detecting device according to the first aspect of the invention, a target having a reflecting portion provided around the rotating shaft, a light receiving portion facing the target is provided, and As the axis rotates, the position of the reflection section facing the light receiving section is configured such that the target changes periodically and continuously, by the light receiving section arranged at a position separated from the target, Since the position of the reflection part is detected, the rotation angle of the rotation shaft is obtained from the position of the reflection part which is opposed to the light detection part and does not include the part that slides in contact with the rotation of the rotation shaft. It becomes possible.

In the case of the rotation angle detecting device according to the second invention, a target is provided on the rotating shaft, and a light receiving portion facing the target is provided. As the rotating shaft rotates, the target faces the light receiving portion of the target. The surface position of the part is
By configuring the target to change periodically and continuously, the surface position of the target is detected by the light receiving unit arranged at a position separated from the target. The rotation angle of the rotation shaft can be obtained from the surface position of the target facing the light detection unit detected by the light receiving unit, not including the portion where the rotation occurs.

In the case of the torque detecting device according to the third aspect of the present invention, the targets are provided at two positions in the axial direction of the rotating shaft, and the light receiving sections are arranged outside each of them, and based on the detection results of these light receiving sections. The rotation torque is determined based on the difference between the rotation angles determined for each. Therefore, it does not include a portion that slides in contact, and it is possible to improve the durability of the device as compared with the related art.

In the case of the torque detecting device according to the fourth aspect of the present invention, targets are provided on the first axis and the second axis which are coaxially connected via a torsion bar, and the light receiving sections are arranged outside each of them. Then, a difference in rotation angle between the first axis and the second axis caused by torsion of the torsion bar is determined by using the detection result of the light receiving unit, and the first axis and the second axis are determined using the result. The rotational torque applied to the motor is detected. Therefore, it does not include a portion that slides in contact, and it is possible to improve the durability of the device as compared with the related art.

In the case of the steering device according to the fifth invention, one of the rotation angle detection device according to the first or second invention and the torque detection device according to the third or fourth invention which does not include a portion that slides in contact. Alternatively, both are applied to a steering device of an automobile, and a rotation angle (steering angle) of a steering shaft and a detection value of a rotation torque (steering torque) applied to the steering shaft are obtained, and these results are used for steering assist. Used for various controls such as motor drive control. Therefore, the present invention has an excellent effect, for example, it is possible to improve the durability of the device as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a main part of a steering device according to a first embodiment of the present invention.

FIG. 2 is a graph showing an output of a line sensor.

FIG. 3 is an explanatory diagram for explaining a relationship between a position of a reflector in the axial direction of a steering shaft and a rotation angle of an input shaft or an output shaft.

FIG. 4 is a schematic diagram illustrating a configuration of a main part of a steering device according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating a relationship between a position of a reflector in a radial direction of a steering shaft and a rotation angle of an input shaft or an output shaft.

FIG. 6 is a schematic diagram illustrating a configuration of a main part of a steering device according to a third embodiment of the present invention.

FIG. 7 is a schematic diagram illustrating a configuration of a main part of a steering device according to a fourth embodiment of the present invention.

FIG. 8 is a graph illustrating a relationship between an output of an optical distance sensor and a rotation angle of an input shaft or an output shaft.

FIG. 9 is a schematic diagram showing a configuration of a main part of a steering device according to a fifth embodiment of the present invention.

FIG. 10 is a schematic diagram illustrating a configuration of a main part of a steering device according to a sixth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1A, 1B Line sensor 1a Sensor box 2 Target 3 Steering axis (rotating axis) 4 Arithmetic processing unit 5A, 5B Optical distance sensor 20 Reflecting unit 30 Steering wheel 31 Input axis (first axis) 32 Output axis (second axis) 34 Torsion bar

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // F02B 77/08 F02B 77/08 Z G01D 5/34 DF Term (Reference) 2F051 AA01 AB03 BA03 2F065 AA42 BB03 BB06 BB27 FF17 FF18 FF19 GG01 GG16 HH05 JJ02 JJ25 MM04 QQ05 QQ28 2F103 CA03 DA01 DA04 DA13 EA03 EA12 EA13 EB01 EB14 EB28 EB32 EB33 3D033 CA16 CA17 CA28 CA29

Claims (5)

[Claims] 1. A rotation angle detection device for detecting a rotation angle of a rotation shaft, wherein a detected position changes periodically and continuously as the rotation shaft rotates, along a circumferential direction of the rotation shaft. A target having a reflector provided, and a light receiving unit disposed opposite to the target, receiving light reflected from the target facing the target, and detecting the position of the reflector based on the received light. Wherein the rotation angle of the rotation axis is obtained based on the position of the reflection unit detected by the rotation angle detection device. 2. A rotation angle detection device for detecting a rotation angle of a rotation axis, wherein the target has a surface shape such that a detected surface position changes periodically and continuously as the rotation axis rotates. A light receiving unit that is disposed to face the target, receives reflected light from the facing target, and detects a surface position of the target based on the received light, based on the surface position of the target detected by the light receiving unit. ,
A rotation angle detection device, wherein the rotation angle of the rotation shaft is obtained. 3. The rotation angle detecting device according to claim 1 or 2 is provided at two places separated in the axial direction of the rotation shaft, respectively.
A torque detection device characterized in that a rotation torque applied to the rotation shaft is obtained based on a difference between the rotation angles detected by each of the rotation angle detection devices. 4. The rotating shaft is a connected body of a first shaft and a second shaft coaxially connected via a torsion bar,
4. The torque detecting device according to claim 3, wherein the targets are arranged in the vicinity of a connecting portion between the first axis and the second axis. 5. The rotation angle detecting device according to claim 1, wherein a steering shaft that connects a steering wheel and a steering mechanism is configured as the rotation shaft, and the torque detection according to claim 3 or 4. A steering device comprising one or both of the devices.