JP3348624B2 - Rotation angle detector - Google Patents

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 steering angle of a steering wheel of a vehicle, for example.

[0002]

2. Description of the Related Art A non-contact potentiometer has been proposed as a detecting device for electrically detecting the rotation angle (rotational displacement) of a rotating member (Japanese Patent Laid-Open No. Hei 6-137807).

In the non-contact potentiometer disclosed in the above publication, a plurality of electrode plates made of a conductor are arranged opposite to each other to form a parallel plate capacitor connected in series of two or more.
Furthermore, the movable plate attached to the rotating shaft is arranged in the gap between the electrode plates facing each other with a phase shift.

In this non-contact potentiometer, the capacity of a parallel plate capacitor composed of a plurality of electrode plates changes linearly in accordance with the rotation angle of a rotating shaft. The rotation angle (rotational displacement) of the shaft can be detected. Further, since the electrode plate and the movable plate do not come into contact with each other, there is an advantage that the life is extended and the temperature characteristics are improved.

However, in the non-contact potentiometer disclosed in the above publication, the range of one rotation of the rotating shaft (360
Although the rotation angle (rotational displacement) can be detected in the rotation angle range of degrees (that is, in the range of -180 degrees to +180 degrees), the absolute rotation angle of the rotation axis is determined for a larger rotation. Not detectable.

Therefore, if the non-contact potentiometer is applied as a sensor for detecting the steering angle of a steering wheel of a vehicle, for example, the steering angle range (so-called lock-to-lock) of the steering wheel is usually three or more turns. When the steering wheel is steered more than twice, there is a disadvantage that this cannot be detected. For this reason, for example, if the power is turned on to the non-contact potentiometer at the time when the steering wheel is steered (rotated) one rotation (360 degrees) or more, an erroneous steering angle (rotation angle) will be detected. .

[0007]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described circumstances, and is capable of detecting an absolute rotation angle when a rotating member is rotated, and realizing this with a simple structure. The purpose is to get the device.

[0008]

According to a first aspect of the present invention, there is provided a rotation angle detecting device which is formed in a belt shape and wound in a spiral shape, one end of which is connected to a fixed side and the other end of which is connected to a rotating member. A band member, a pair of electrodes provided on one surface side of the band member with a diagonal line interposed therebetween, detection means for detecting a capacitance between the pair of electrodes, and a detection value of the capacitance. Computing means for computing the rotation angle of the rotating member.

In the rotation angle detecting device according to the first aspect, a pair of electrodes is provided on the spirally wound band member, thereby substantially forming a capacitor.

This band member is tightened and unwound according to the rotation of the rotating member. That is, the band member (a pair of electrodes) wound in a spiral shape changes the density of the spiral shape in accordance with the rotation of the rotating member, and furthermore, the facing area of the pair of electrodes facing each other in the spiral shape is also the rotating member. Is changed according to the rotation of. The spiral capacitance of the band member (a pair of electrodes) changes and the opposing area changes, the capacitance of the capacitor formed by the pair of electrodes provided on the band member changes, and the potential between the electrodes fluctuates. I do. The capacitance (potential) between the electrodes is detected by the detecting means.

Here, the capacitance of the capacitor formed by the pair of electrodes, that is, the potential between the electrodes changes linearly in accordance with the rotation angle of the rotating member. Then, the calculation means calculates the absolute rotation angle of the rotating member.

As described above, in the rotation angle detecting device according to the first aspect, the rotation angle of the rotation member is detected based on the change in the spiral density of the band member (pair of electrodes) and the change in the facing area. Therefore, the absolute rotation angle of the rotating member can be detected, for example, even if the rotation angle of the rotating member is one rotation or more (360 degrees or more).

Therefore, the rotation angle detecting device can be suitably used as a sensor for detecting a steering angle of a steering wheel of a vehicle, for example.

According to a second aspect of the present invention, there is provided a rotation angle detecting device.
The rotation angle detection device according to claim 1, wherein the rotation member is a steering wheel of a vehicle, and the band member is
A transmission line for transmitting a signal from the vehicle body side to the steering wheel side is provided.

In the rotation angle detecting device according to the second aspect, the rotating member is a steering wheel of the vehicle, and the band member is a transmission wire (for example, an air line) for transmitting a signal from the vehicle body side to the steering wheel side. Spiral cable for bag).

When the steering wheel is steered, the transmission wiring (spiral cable) is tightly wound and unwound, thereby changing the spiral density and the facing area of the electrodes.

Therefore, as described above, the steering angle of the steering wheel is detected as the absolute rotation angle based on the spiral density of the transmission wiring (spiral cable) and the change in the facing area of the electrodes.

As described above, in the rotation angle detecting device according to the second aspect, even if the steering angle range (so-called lock-to-lock) of the steering wheel is one rotation or more (360 degrees or more), it is detected. can do. For this reason, for example, the steering wheel rotates once (360
The steering angle (absolute rotation angle) can be accurately detected even when the power is turned on to the rotation angle detection device at the time when the steering (rotation) is performed more than (degree).

[0019]

FIG. 1 schematically shows an entire configuration of a rotation angle detecting device 10 according to an embodiment of the present invention.

The rotation angle detecting device 10 is applied as a sensor for detecting a steering angle of a steering wheel of a vehicle, and includes a spiral cable 1 as a band member.
2 is provided. As shown in FIG. 3, the spiral cable 12 is arranged around a steering shaft 16 (rotating member) of a steering device 14 of a vehicle, and a transmission wiring (for transmitting a signal from the vehicle body side to the steering wheel side). For example, the airbag is not shown).

As shown in FIG. 2, the spiral cable 12
Is formed in a band shape and spirally wound, and has one end connected to a fixed side of the steering device 14 and the other end connected to a steering shaft 16 as a rotating member.

As shown in FIG. 1, the spiral cable 12
On one surface side, a pair of electrodes 18A, 18
B is provided. Each of the electrodes 18A and 18B is connected to a detection unit 20 as detection means, and a power supply 22 is connected to the detection unit 20. Thereby, the spiral cable 12 (a pair of electrodes 18A, 1A)
8B) substantially forms a capacitor, and
The detection unit 20 is configured to detect the potential between the electrodes 18A and 18B according to the degree of density of the spiral cable 12.

The detecting section 20 is connected to the calculating section 24. The calculation unit 24 can calculate the rotation angle of the steering shaft 16 based on the potential detected by the detection unit 20.

In the rotation angle detecting device 10 having the above structure, the steering wheel is steered and the steering shaft 1
6 is rotated, the spiral cable 12 connected to the steering shaft 16 is connected to the steering shaft 1.
The winding is tightened and unwound according to the rotation of 6. For example, when the steering shaft 16 is rotated clockwise in FIG. 4, the spiral cable 1 is rotated as shown in FIG.
When the steering shaft 16 is rotated counterclockwise in FIG. 4, the spiral cable 12 is unwound as shown in FIG. 4B.

That is, the spiral cable 12 (a pair of electrodes 18A, 18B) wound in a spiral shape has a spiral density that changes in accordance with the rotation of the steering shaft 16, and furthermore, a pair of spirally opposed coils. The facing area of the electrodes 18A and 18B is also changed according to the rotation of the steering shaft 16. As the spiral cable 12 (the pair of electrodes 18A and 18B) changes in the spiral density and the opposing area, the capacitance of the capacitor formed by the pair of electrodes 18A and 18B provided on the spiral cable 12 becomes larger. Changes, the electrode 18A,
The potential between 18B fluctuates. The electrodes 18A, 1
The potential between 8B is detected by the detection unit 20.

Here, the capacitance of the capacitor formed by the pair of electrodes 18A and 18B, that is, the potential between the pair of electrodes 18A and 18B is determined by the steering shaft 16
, Linearly changes according to the rotation angle of the steering shaft 16, and is calculated as the absolute rotation angle of the steering shaft 16 by the calculation unit 24 based on the detection result of the capacitance (potential) of the capacitor.

As described above, in the rotation angle detecting device 10 according to the present embodiment, the spiral shaft 12 (the pair of electrodes 18A and 18B) has the spiral shaft 12 based on the change in the spiral density and the change in the facing area. Since the rotation angle is configured to be detected, the absolute rotation angle of the steering shaft 16 can be detected. For example, even when the steering shaft 16 has rotated one or more rotations (a rotation angle of 360 degrees or more), it can be detected. Can be. For this reason, for example, the steering shaft 16 makes one rotation (36
Even when the rotation angle detecting device 10 is turned on at the time of turning (steering) by 0 ° or more, the steering angle (absolute rotation angle) can be accurately detected.

Further, in the rotation angle detecting device 10 according to the present embodiment, the structure is established by providing the existing spiral cable 12 with the pair of electrodes 18A and 18B.
This can be realized with a simple structure without adding new parts or increasing the cost.

In the above-described embodiment, the configuration in which the rotation angle detecting device 10 is applied as a sensor for detecting the steering angle of the steering wheel of a vehicle has been described. The rotation angle detection device 10 may be applied to detect the rotation angle of the rotation angle.

Further, in the above embodiment, a pair of electrodes 18A and 18B are provided on the spiral cable 12 as transmission wiring (for energizing the airbag) for transmitting a signal from the vehicle body side to the steering wheel side. The configuration is not limited to this, but a configuration in which a dedicated spiral electrode is provided may be employed.

[0031]

As described above, the rotation angle detecting device according to the present invention is excellent in that it can detect the absolute rotation angle when the rotating member rotates, and can realize this with a simple structure. It has the effect.

[Brief description of the drawings]

FIG. 1 is a schematic overall configuration diagram of a rotation angle detection device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a spiral cable of the rotation angle detecting device according to the embodiment of the present invention.

FIG. 3 is a perspective view of a steering device of a vehicle to which the rotation angle detection device according to the embodiment of the present invention is applied.

FIG. 4 is a plan view showing the tight tightening and unwinding (sparse and dense state) of the spiral cable of the rotation angle detecting device according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Rotation angle detector 12 Spiral cable (band member) 16 Steering shaft 18A electrode 18B electrode 20 Detector (detector) 24 Calculator (calculator)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01B 7/30 G01D 5/24

Claims (2)

(57) [Claims] 1. A band member formed in a band shape and wound in a spiral shape, one end of which is connected to a fixed side and the other end of which is connected to a rotating member. A pair of electrodes, a detecting unit that detects a capacitance between the pair of electrodes, and a calculating unit that calculates a rotation angle of the rotating member based on a detected value of the capacitance. Angle detector. 2. The vehicle according to claim 1, wherein the rotating member is a steering wheel of a vehicle, and the band member is a transmission wire for transmitting a signal from a vehicle body to the steering wheel. The rotation angle detecting device according to any one of the preceding claims.