JP2002148015A - Steering angle sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering angle sensor which can detect a steering angle nearly simultaneously with the turning-on of an IG key without continuously detecting steering angle information when the IG key is turned off. SOLUTION: The steering angle sensor is provided with a ring belt-shaped magnet 23 which is attached through a yoke 22 to the output shaft 21 of a gear mechanism used to convert the whole rotation-angle range of a steering shaft into a rotation-angle range at less than one rotation in both directions and which is magnetized in the radial direction; stators 24 which are fixed to, and arranged at, the outer circumference of the ring belt-shaped magnet at an interval of 90 deg. by keeping prescribed gaps 25; and magnetic sensors 26, 27 which are installed at two adjacent gaps from among the four gaps. One from among the two magnetic sensors is used to judge regions at an interval of 90 deg., and the other is used to acquire an angle signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a steering angle sensor for detecting a rotational position of a steering shaft of a vehicle.

[0002]

2. Description of the Related Art A steering angle sensor detects a rotational position of a steering shaft as an angle (absolute steering angle) based on a true neutral position. Since this steering angle sensor is important as one of sensors used in vehicle control in an automobile or the like, various proposals have conventionally been made.

For example, Japanese Patent Application Laid-Open No. H11-264725 (conventional example 1) discloses a rotation angle detection device capable of detecting and storing information on the rotation direction and rotation angle of a steering shaft while the engine is stopped. This rotation angle detection device employs an incremental method for counting the number of ON / OFF of a signal.

Japanese Patent Application Laid-Open No. 5-322599 (Conventional Example 2) discloses a backup type multi-rotation type absolute position detector capable of high-speed response even when the main power supply is cut off. This multi-rotation type absolute position detector uses a rotating disk provided with information such that a digital value of “0” or “1” can be detected by the detection element, and “0” and “0” detected by the detection element are used. A gray code system for detecting an angle by a combination of 1 "is adopted.

In Japanese Patent Application Laid-Open No. 11-287608 (conventional example 3), an ignition switch (hereinafter referred to as "I
A vehicle steering sensor capable of detecting an accurate absolute steering angle early after turning on a "G key") is disclosed. In this vehicle steering sensor, in order to be able to detect the entire rotation region of the steering wheel,
A rotation speed detection unit using a gear reduction mechanism is provided.

[0006]

However, in the conventional example 1, it is necessary to continue detecting the steering angle even when the IG key is turned off, and it is necessary to consider power consumption at this time.

In the second conventional example, the code to be applied to the rotating disk needs to be densified in accordance with the high resolution, so that the number of detecting elements increases.

Further, in the conventional examples 1 and 2, since the coded digital signal is processed, the overall design is changed in accordance with the diameter of the steering shaft on which the steering angle sensor is mounted and the specification for resolving the angle. The need comes out.

Further, in the third conventional example, since the number of rotation number detecting units is increased, there is a problem that it is necessary to match the detailed angle detecting unit with the reference position of the rotation number detecting unit.

The present invention has been made in view of such circumstances, and an object thereof is to detect a steering angle almost simultaneously with turning on an IG key without continuously detecting steering angle information when the IG key is turned off. It is an object of the present invention to provide a steering angle sensor which can be used.

[0011]

According to a first aspect of the present invention, there is provided a steering angle sensor for converting a full rotation angle range of a steering shaft into a rotation angle range of less than one rotation in both directions. And a ring-shaped magnet attached to an output shaft of the gear mechanism via a yoke and magnetized in the radial direction, and a 90-degree interval around a circumference of the ring-shaped magnet with a predetermined gap. , And two adjacent gaps among four gaps formed between the stators, one of which is 9
A magnetic sensor used for determining an area at an interval of 0 degrees, and the other magnetic sensor used for obtaining an angle signal.

A steering angle sensor according to a second aspect of the present invention is mounted on a gear mechanism for converting the entire rotation angle range of the steering shaft into a rotation angle range of less than one rotation in both directions, and an output shaft of the gear mechanism. A disc-shaped magnet arranged on the side surface of the disc-shaped yoke and magnetized in the thickness direction, and fixed on one side surface of the disc-shaped magnet at a 90-degree interval with a predetermined gap therebetween. And two magnetic poles provided in adjacent two of the four gaps formed between the stators, one of which is used for determining an area at intervals of 90 degrees, and the other is used for obtaining an angle signal. And a sensor.

A steering angle sensor according to a third aspect of the present invention includes a gear mechanism for converting the entire rotation angle range of the steering shaft into a rotation angle range of less than one rotation in both the left and right directions, and an output shaft of the gear mechanism. An annular band-shaped magnet arranged on the inner peripheral surface of the attached cylindrical yoke and magnetized in the radial direction, and opposed to the inner peripheral surface of the annular band-shaped magnet, each of which is 90 ° with a predetermined gap. A stator is fixedly arranged at intervals and provided in two adjacent gaps among four gaps formed between the stators.
And a magnetic sensor used for determining the area of the degree interval and the other being used for obtaining an angle signal.

According to the present invention, the rotation angle range of the steering shaft is converted into a range of less than one rotation by the gear mechanism, and two adjacent gaps among the gaps between the regions that divide this one rotation angle range into four equal parts. A magnetic sensor is provided in the gap. The outputs of the two magnetic sensors are 0 to 18 respectively.
In the range of 0 degrees and the range of 180 to 360 degrees, the direction of change shows a linear change in which the change direction is reversed. Used for acquisition. As a result, angle information is obtained in the form of an analog signal in each region at intervals of 90 degrees.

[0015]

FIG. 1 is a structural diagram showing a steering angle sensor according to an embodiment of the present invention. As shown in FIG.
A reduction gear mechanism 2 is attached to the steering shaft 1. The reduction gear mechanism 2 is provided with an entire rotation angle range of the steering shaft 1 (for example, an angle range of right and left two rotations;
± 720 degrees) in both directions into a rotation angle range of less than one rotation (360 degrees).

In the illustrated example, this reduction gear mechanism has a maximum radius gear 2a that rotates integrally with the steering shaft 1.
A large radius gear 2b that rotates while meshing with the largest radius gear 2a; a small radius gear 2c that is attached to the rotation shaft of the large radius gear 2b and that rotates integrally with the large radius gear 2b; And a medium radius gear 2d that rotates.

With this configuration, the rotation shaft of the medium radius gear 2d constituting the output shaft rotates within an angle range of less than one left and right rotation. The detection unit 3 is attached to the rotation shaft of the middle radius gear 2d, and the output of the detection unit 3 is guided to the signal processing circuit 4.

The detecting section 3 is configured as shown in FIGS. FIG. 2 is a first configuration example of the detection unit 3. FIG. 3 is a second configuration example of the detection unit 3. FIG.
This is a third configuration example.

In FIG. 2, (1) is a plan view, and (2) is a perspective view. As shown in FIG. 2, an annular band-shaped yoke 22 is fixed to the rotating shaft 21 of the middle radius gear 2 d, and an annular band-shaped magnet 23 is bonded to the outer peripheral side surface of the annular band-shaped yoke 22. The annular belt-shaped yoke 22 is made of a soft magnetic material such as soft iron. The annular belt-shaped magnet 23 is magnetized in the radial direction.

The four stators 24 are mounted on the ring-shaped magnet 2.
3 are arranged on the outer periphery of the outer peripheral surface of the outer peripheral surface 3 at predetermined intervals. The four stators 24 are fixedly arranged at 90-degree intervals with a predetermined gap 25 therebetween.
Two adjacent gaps 25 among the four gaps 25 are provided with Hall elements 26 and 27 as magnetic sensors.
Are provided respectively. The output terminals of the Hall elements 26 and 27 are connected to the signal processing circuit 4.

Next, in FIG. 3, (1) is a plan view,
(2) is a perspective view. As shown in FIG. 3, a disc-shaped yoke 32 is fixed to the rotation shaft 21 of the middle radius gear 2d.
A disk-shaped magnet 33 is bonded to one surface of the disk-shaped yoke 32. The disc-shaped yoke 32 is made of a soft magnetic material such as soft iron. The disc-shaped magnet 33 is magnetized in the thickness direction.

The four stators 34 are mounted on the disc-shaped magnet 23.
Are arranged opposite to the peripheral surface of the panel at a predetermined interval. The four stators 34 are fixedly arranged at 90-degree intervals with a predetermined gap 25 therebetween.
Two adjacent gaps 25 among the four gaps 25 are provided with Hall elements 26 and 27 as magnetic sensors.
Are provided respectively. The output terminals of the Hall elements 26 and 27 are connected to the signal processing circuit 4.

Next, in FIG. 4, (1) is a plan view,
(2) is a perspective view. As shown in FIG. 4, a cylindrical yoke 42 is fixed to the rotation shaft 21 of the middle radius gear 2d.
An annular belt-shaped magnet 43 is bonded to the inner peripheral surface of the cylindrical yoke 42. The cylindrical yoke 42 is made of a soft magnetic material such as soft iron. The annular belt-shaped magnet 43 is magnetized in the radial direction.

The four stators 44 are provided with the annular band magnet 4.
3, it is disposed facing the inner peripheral surface thereof at a predetermined interval. The four stators 44 are fixedly arranged at intervals of 90 degrees with a predetermined gap 25 therebetween. Two adjacent gaps 25 among the four gaps 25 are provided with Hall elements 26 and 27, respectively, which are magnetic sensors. The output terminals of the Hall elements 26 and 27 are connected to the signal processing circuit 4.

In the configuration of the above three detectors, when the ring-shaped magnet 23, the disk-shaped magnet 33, and the ring-shaped magnet 43 rotate, the magnetic flux density in a certain gap 25 linearly changes according to the rotation angle. Since the output changes, an output corresponding to the rotation angle can be obtained in an analog manner by the Hall element 26 or 27 provided there.

However, in one gap 25,
For example, when the magnetic flux density increases due to the angle change from 0 to 180 degrees (deg), the magnetic flux density decreases in the angle range of 180 to 360 degrees (deg), so the output corresponding to two angles during one rotation Is obtained. Therefore, the Hall elements 26 and 27 are respectively placed in two adjacent gaps 25.
To obtain one angle information within 360 degrees by the outputs of the two Hall elements 26 and 27 having different phases.

Next, the signal processing circuit 4 will be described with reference to FIGS.
Will be described. This makes clear how the signal processing circuit 4 is configured. FIG. 5 is an output characteristic diagram of the two Hall elements 26 and 27. FIG. 6 is an explanatory diagram of how to use two Hall element outputs.

In FIG. 5, the angle ranges of one rotation left and one rotation right are divided at 90-degree intervals.
The angle range of 90 deg is area 1, the angle range of 90 to 180 deg is area 2, and the angle range of 180 to deg is area 3 and 270.
The angle range of 360 deg is defined as region 4.

The phase of the output of the Hall element 26 and the phase of the output of the Hall element 27 are determined by the rotation direction of the steering shaft 1. Now, it is assumed that the output of the Hall element 26 is ahead of the output of the Hall element 27 in phase. FIG.
As shown in (1), the output (A) of the Hall element 26 is in the region 1
Is a triangular wave signal having a maximum value a and a minimum value b in region 3. The output (b) of the Hall element 27 is a triangular wave signal having the maximum value c in the area 2 and the minimum value d in the area 4.

That is, regions 1 and 2 have maximum values a and c, and regions 3 and 4 have minimum values b and d. They are,
The output (a) of the hall element 26 and the output (b) of the hall element 27 are shown alternately.

When attention is paid to the boundary of the area, 0 deg
(360deg) and 180deg, both increase in the same direction,
In the process of decreasing, one shows a predetermined value e exceeding the intermediate value MV, and the other shows a predetermined value f below the intermediate value MV. At 90 deg and 270 deg, if one is in the process of increasing and the other is in the process of decreasing, the directions are reversed, but both values are equal, and the predetermined value g or A predetermined value h below the intermediate value MV is shown.

In this case, in the region 1, the output (b) of the Hall element 27 linearly increases from a predetermined value f below the intermediate value MV to a predetermined value e exceeding the intermediate value MV. In region 2, the output (A) of the Hall element 26 decreases linearly from a predetermined value e exceeding the intermediate value MV to a predetermined value f below the intermediate value MV. In the region 3, the output (b) of the Hall element 27 changes from the predetermined value e exceeding the intermediate value MV to the intermediate value M
It decreases linearly to a predetermined value f below V. Also,
In the region 4, the output (A) of the Hall element 26 is the intermediate value M
It linearly increases from a predetermined value f below V to a predetermined value e exceeding the intermediate value MV.

As described above, the Hall element output indicating the maximum value a, c or the minimum value b, d is used for angle area determination, and the angle information in the determined area is obtained from the other Hall element output. It can be understood that it suffices.

In the example of FIG. 5, as shown in FIG. 6, in the area 1, the output (a) of the Hall element 26 becomes a determination signal of the area 1, and the output (b) of the hall element 27 becomes the determination signal of the area 1. It becomes a detailed angle signal. In the area 2, the output (B) of the Hall element 27 becomes the determination signal of the area 2, and the output (A) of the Hall element 26 becomes the detailed angle signal of the area 2. In area 3,
The output (A) of the Hall element 26 becomes a determination signal of the area 3, and the output (B) of the Hall element 27 becomes a detailed angle signal of the area 3. In the area 4, the output (B) of the Hall element 27 is a determination signal of the area 2, and the output (A) of the Hall element 26 is a detailed angle signal of the area 4.

Then, the signal processing circuit 4 corrects the angle value obtained as described above by the amount converted by the reduction gear mechanism 2. For example, when the rotation amount of the steering shaft 1 is reduced to 1/4, the obtained angle value is quadrupled. As a result, an angle (absolute steering angle) of the entire steering angle range is obtained as an output of the signal processing circuit 4. It goes without saying that the operation for obtaining the absolute steering angle described above is executed almost simultaneously with turning on the IG key.

In this embodiment, the Hall element is used as the magnetic sensor, but other elements, for example, having a variable resistance value can be used.

[0037]

As described above, according to the present invention,
With a simple configuration, the current steering angle information can be instantaneously detected when the IG key is turned on. Further, a change in the dimensions of the steering shaft can be dealt with only by changing the gear mechanism. Since the obtained angle value is obtained in an analog manner, there is no need to change the design for each required resolution, and the angle value can be easily handled. Therefore, according to the present invention, a highly versatile steering angle sensor can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a steering angle sensor according to the present invention.

FIG. 2 is a first configuration example of a detection unit. (1) is a plan view,
(2) is a perspective view.

FIG. 3 is a second configuration example of a detection unit. (1) is a plan view,
(2) is a perspective view.

FIG. 4 is a third configuration example of a detection unit. (1) is a plan view,
(2) is a perspective view.

FIG. 5 is an output characteristic diagram of two Hall elements.

FIG. 6 is an explanatory diagram of how to use two Hall element outputs.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steering shaft 2 Reduction gear mechanism 2a Maximum radius gear 2b Large radius gear 2c Small radius gear 2d Medium radius gear 3 Detecting unit 4 Signal processing circuit 21 Rotation shaft 22 Ring-shaped yoke 23, 43 Ring-shaped magnet 24, 34, 44 Stator 25 Gap 26, 27 Hall element 32 Disk-shaped yoke 33 Disk-shaped magnet 42 Cylindrical yoke (A) Output characteristic of Hall element 26 (B) Output characteristic of Hall element 27 MV Intermediate values a, c Maximum values b, d Minimum value e, g Predetermined value exceeding intermediate value MV f, h Predetermined value falling below intermediate value MV

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F063 AA36 BA08 BD16 CA40 DA02 DB07 DD03 EA03 GA52 GA61 GA68 LA02 3D030 DC29 3D033 CA29 DB05

Claims (3)

[Claims] 1. A gear mechanism for converting an entire rotation angle range of a steering shaft into a rotation angle range of less than one rotation in both directions on the left and right sides, and a radius attached to an output shaft of the gear mechanism via an annular band-shaped yoke. A ring-shaped magnet magnetized in a direction; a stator fixedly arranged at an interval of 90 degrees with a predetermined gap around the outer circumference of the ring-shaped magnet; and 4 formed between the stators. A magnetic sensor provided in two adjacent gaps among the two gaps, one of which is used for determining an area at intervals of 90 degrees and the other is used for obtaining an angle signal. Angle sensor. 2. A gear mechanism for converting the entire rotation angle range of the steering shaft into a rotation angle range of less than one rotation in the left and right directions, and disposed on a side surface of a disk-shaped yoke attached to an output shaft of the gear mechanism. A disk-shaped magnet magnetized in the thickness direction, a stator fixedly disposed on one side surface of the disk-shaped magnet at 90 ° intervals with a predetermined gap therebetween, and formed between the stators. A magnetic sensor provided in two adjacent ones of the four gaps, one of which is used for determining an area at intervals of 90 degrees, and the other is used for obtaining an angle signal. Steering angle sensor. 3. A gear mechanism for converting the entire rotation angle range of the steering shaft into a rotation angle range of less than one rotation in both directions on the left and right sides, and on an inner peripheral surface of a cylindrical yoke attached to an output shaft of the gear mechanism. A ring-shaped magnet magnetized in the radial direction, and a stator opposed to the inner peripheral surface of the ring-shaped magnet, each of which is fixedly arranged at 90 ° intervals with a predetermined gap, and A magnetic sensor provided in two adjacent gaps among the four gaps formed between the stators, one of which is used for determining a region at intervals of 90 degrees and the other is used for obtaining an angle signal; A steering angle sensor, comprising: