JP2004191138A - Steering angle detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering angle detection device capable of always determining the absolute steering angle of a steering shaft highly accurately without being influenced by an error in a sensing part. <P>SOLUTION: This device has a magnetostrictive line 3 wound spirally on a fixed case 5 provided on the periphery of the steering shaft 2, and a magnet 7 fixed on a rotary case 6 rotating linking with the steering shaft 2, guided by the magnetostrictive line 3, and disposed slidably in the axial direction of the steering shaft 2. A current is made to flow from one end side of the magnetostrictive line 3, and a portion where magnetic strain is generated is detected by the magnet 7, and the distance from the one end side to the portion where the strain is generated is calculated, and the rotation angle of the steering shaft 2 is detected based on the calculation result. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a steering angle detection device that detects a steering angle of a steering of a vehicle, and more particularly to a technique for detecting an absolute steering angle with high accuracy.
[0002]
[Prior art]
The steering shaft of an automobile can rotate several rotations when the entire rotation angle in the left-right direction is matched. For this reason, when detecting the steering angle, it is not possible to judge the current rotation only by detecting the absolute angle of the rotating plate that rotates in synchronization with the steering.
[0003]
Therefore, in order to solve such a problem, a steering angle detecting device described in a CD-ROM of Japanese Utility Model Laid-Open No. 5-2007 (hereinafter referred to as Patent Document 1) has been proposed.
[0004]
In Patent Document 1, a steering wheel rotating gear that rotates in conjunction with a steering shaft, and a speed increasing gear that meshes with the gear and has fewer teeth than the steering wheel rotating gear are arranged, and the steering wheel rotating gear; The absolute steering angle is calculated based on output signals of potentiometers attached to both the speed increasing gears.
[0005]
[Patent Document 1]
No. 5-2007 CD-ROM (Fig. 1)
[0006]
[Problems to be solved by the invention]
However, the steering angle detection device described in Patent Document 1 described above uses a method of calculating an absolute steering angle using outputs of potentiometers attached to two gears having a period shift from each other. However, if the error of each sensing unit becomes large, an incorrect cycle may be recognized. In such a case, there is a problem that an angle far from the true value is calculated.
[0007]
The present invention has been made to solve such a conventional problem, and an object of the present invention is to always obtain the absolute steering angle of the steering shaft with high accuracy without being affected by the error of the sensing unit. It is an object of the present invention to provide a steering angle detecting device that can perform the following.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 of the present application is directed to a steering angle detecting device for detecting a rotation angle of a steering shaft mounted on a vehicle, which is disposed on one of the steering shaft side and the column side. Provided on the other side of the steering shaft side or the column side, and guided by the spirally wound magnetostrictive wire, and along the axial direction of the steering shaft. And a slidable magnet, having a current flowing from one end of the magnetostrictive wire, detecting a portion where the magnet is magnetically distorted, and detecting a portion from the one end to the portion where the distortion is generated. A distance is calculated, and a rotation angle of the steering shaft is detected based on the calculation result.
[0009]
The invention according to claim 2 is a steering angle detecting device for detecting a rotation angle of a steering shaft mounted on a vehicle, wherein the magnetostrictive wire spirally wound around a fixed case provided around the steering shaft. And a magnet attached to a rotating case that rotates in conjunction with the steering shaft, guided by the magnetostrictive wire, and disposed to be slidable in the axial direction of the steering shaft, and one end of the magnetostrictive wire. A current flows from the side, a portion where magnetic distortion is generated by the magnet is detected, a distance from the one end to the portion where the distortion is generated is calculated, and based on the calculation result, the rotation of the steering shaft is performed. It is characterized in that the angle is detected.
[0010]
According to a third aspect of the present invention, in the steering angle detecting device for detecting a rotation angle of a steering shaft mounted on a vehicle, a magnetostrictive wire spirally wound around a fixed case provided around the steering shaft. A magnet attached to a rotating case that rotates in conjunction with the steering shaft, guided by the magnetostrictive wire, and slidably disposed in the axial direction of the steering shaft; and a current from one end of the magnetostrictive wire. A magnetic detecting means for detecting a position of a magnetic distortion generated by the magnetostrictive line, and a steering angle for obtaining a steering angle of the steering shaft based on a position of the distortion signal detected by the magnetic detecting means. And angle detecting means.
[0011]
According to a fourth aspect of the present invention, the magnetism detecting means is configured such that, after applying a current to the magnetostrictive wire, a pressure wave generated in the magnetostrictive wire is generated by a magnetic strain caused by a magnetic field generated by the magnet. The generation position of the distortion signal is detected based on the time required to return.
[0012]
The invention according to claim 5 is characterized in that the magnetostrictive wire is arranged in a spiral cable wound around the steering shaft.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram illustrating a configuration of a steering angle detection device according to an embodiment of the present invention, and illustrates a cross section in a side direction of a steering shaft mounted on a vehicle. As shown in FIG. 1, the steering angle detecting device 1 is disposed around a through hole 11 of a steering shaft 2 mounted on a vehicle, and is fixed to a column side (that is, does not rotate with the steering shaft 2). A fixed case 5, a magnetostrictive wire 3 spirally wound around the fixed case 5, and a pulse current flowing from one end of the magnetostrictive wire 3 connected to one end of the magnetostrictive wire 3. And a magnetic sensor (magnetic detection means) 4 for detecting a pressure wave (distortion signal) generated by the control unit. Further, the magnetic sensor 4 is connected to a steering angle detection unit (steering angle detection means) 10 as shown in FIG.
[0014]
A rotating case 6 that rotates together with the steering shaft 2 is provided on an outer peripheral portion of the fixed case 5, and an inner peripheral surface of the rotating case 6 A magnet 7 slidable in the direction (ie, the longitudinal direction of the steering shaft 2) is provided.
[0015]
Further, a spiral cable 8 for electrically connecting the steering side and the column side is arranged on the outer peripheral side of the rotating case 6.
[0016]
FIG. 2 is an explanatory view showing a state where the magnetostrictive wire 3 is wound around a fixed case 5 on the outer peripheral portion of the steering shaft 2. As shown in FIG. Are wound spirally so that the intervals between turns are equal.
[0017]
The magnetostrictive wire 3 is made of, for example, a material such as Fe-Ni. When a magnetic field is applied to the vicinity of the magnetostrictive wire 3 from the outside, magnetic distortion occurs in this portion.
[0018]
Further, the number of turns of the magnetostrictive wire 3 wound around the fixed case 5 is set to be larger than the number of rotations of the steering (for example, 5 rotations).
[0019]
FIG. 3 is an explanatory diagram showing a state of connection between the magnetostrictive wire 3 and the magnetic sensor 4. As shown in FIG. 3, the magnetostrictive wire 3 is wound around a fixed case 5, and one end of the wire is wound. Is provided with a magnetic sensor 4. Further, a steering angle detection unit 10 for obtaining an absolute steering angle of the steering shaft 2 based on the pressure wave detected by the magnetic sensor 4 is provided.
[0020]
FIG. 4 is an explanatory diagram showing a positional relationship between the magnetostrictive wire 3 and the magnet 7. As shown in the drawing, the magnet 7 slides along a sliding groove 9 formed on the inner peripheral surface of the rotating case 6. The magnet 7 is slid along the sliding groove 9 while being guided by the helically wound magnetostrictive wire 4.
[0021]
Therefore, when the driver turns the steering wheel and the steering shaft 2 is driven to rotate, the rotating case 6 is rotated accordingly. As a result, the magnet 7 moves along the sliding groove 9 in the axial direction of the steering shaft 2. It will slide.
[0022]
Next, an operation of the steering angle detection device 1 according to the present embodiment configured as described above will be described.
[0023]
When the steering angle detection device 1 is driven, the magnetic sensor 4 outputs a pulse current. This pulse current generates a circular magnetic field around the magnetostrictive wire 3. At this time, in a portion of the magnetostrictive wire 3 where the magnet 7 is close, a torsional magnetic field is generated by a combined magnetic field with the magnetic field generated by the magnet 7.
[0024]
At this time, since the magnetostrictive wire 3 is instantaneously deformed, vibration is generated, propagates through the magnetostrictive wire 3 as a pressure wave, and is detected by the magnetic sensor 4. Then, the time from the output of the pulse current to the detection of the pressure wave is measured by the magnetic sensor 4, and based on the measured time, the position where the deformation has occurred in the magnetostrictive wire 3, that is, , The distance to the part where the magnet 7 approaches is calculated.
[0025]
Thereafter, the steering angle detection unit 10 can determine the rotation angle of the steering shaft 2, that is, the absolute steering angle of the steering, based on this distance.
[0026]
In this manner, in the steering angle detection device 1 according to the present embodiment, the magnetostrictive wire 3 is spirally wound around the fixed case 5 around the steering shaft 2, and further, the rotation that rotates in conjunction with the steering shaft 2. The magnet 7 is slidably mounted on the case 6 so that the magnet 7 slides with the rotation of the steering wheel. Further, a pulse current is output from one end of the magnetostrictive wire 3, and the position of the magnet 7 is specified based on the time until the pressure wave returns, and the absolute steering angle of the steering is obtained based on this.
[0027]
Therefore, the absolute steering angle of the steering having a plurality of rotation speeds as a whole can be detected with high accuracy.
[0028]
Further, since the magnetostrictive wires 3 and the magnets 7 are provided inside the spiral cable 8, the size of the device can be reduced.
[0029]
As described above, the steering angle detection device 1 of the present invention has been described based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each unit may be any configuration having the same function. Can be replaced.
[0030]
For example, in the present embodiment, an example in which the magnetostrictive wire 3 is wound around the fixed case 5 and the magnet 7 is arranged on the rotating case 6 has been described. It is also possible to adopt a configuration in which the magnet 3 is wound and the magnet 7 is mounted on the fixed side (column side).
[0031]
【The invention's effect】
As described above, in the steering angle detecting device according to the present invention, the magnetostrictive wire is wound on one of the steering shaft side and the column side of the vehicle, and the other slides in the axial direction of the steering shaft while being guided by the magnetostrictive wire. By attaching a possible magnet and causing magnetic distortion of the magnetostriction line by the magnet, a portion where the magnet is in close proximity is determined, and based on this, the absolute steering angle of the steering is determined. Therefore, unlike the related art, it is possible to detect the absolute steering angle with high accuracy without causing erroneous detection of the steering angle.
[0032]
In addition, since the magnetostrictive wire and the magnet are provided inside the spiral cable, the size of the device can be reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a steering shaft portion of a vehicle on which a steering angle detecting device according to an embodiment of the present invention is mounted.
FIG. 2 is an explanatory view showing a state where a magnetostrictive wire is wound around a fixed case.
FIG. 3 is an explanatory diagram showing a state of connection between a magnetostrictive wire and a magnetic sensor.
FIG. 4 is an explanatory diagram showing a positional relationship between a magnetostrictive line and a magnet.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steering angle detecting device 2 Steering shaft 3 Magnetostrictive wire 4 Magnetic sensor (magnetic detecting means)
Reference Signs List 5 Fixed case 6 Rotating case 7 Magnet 8 Spiral cable 9 Sliding groove 10 Steering angle detector (steering angle detector)
11 Steering shaft penetration

Claims (5)

In a steering angle detection device that detects a rotation angle of a steering shaft mounted on a vehicle,
The steering shaft side, or disposed on one of the column side, a magnetostrictive wire spirally wound,
A magnet disposed on the other side of the steering shaft side or the column side, guided by the spirally wound magnetostrictive wire, and slidable along the axial direction of the steering shaft;
An electric current flows from one end of the magnetostrictive wire, a part where magnetic distortion is generated by the magnet is detected, a distance from the one end to the part where the distortion is generated is calculated, and based on the calculation result, A steering angle detecting device for detecting a rotation angle of the steering shaft. In a steering angle detection device that detects a rotation angle of a steering shaft mounted on a vehicle,
A fixed case provided around the steering shaft, a magnetostrictive wire spirally wound,
A magnet attached to a rotating case that rotates in conjunction with the steering shaft, guided by the magnetostrictive line, and slidably disposed in the axial direction of the steering shaft;
An electric current flows from one end of the magnetostrictive wire, a part where magnetic distortion is generated by the magnet is detected, a distance from the one end to the part where the distortion is generated is calculated, and based on the calculation result, A steering angle detecting device for detecting a rotation angle of the steering shaft. In a steering angle detection device that detects a rotation angle of a steering shaft mounted on a vehicle,
A fixed case provided around the steering shaft, a magnetostrictive wire spirally wound,
A magnet attached to a rotating case that rotates in conjunction with the steering shaft, guided by the magnetostrictive line, and slidably disposed in the axial direction of the steering shaft;
A current is applied from one end side of the magnetostrictive wire, and a magnetic detecting unit that detects a magnetic strain occurrence position generated in the magnetostrictive wire,
Steering angle detection means for obtaining a steering angle of the steering shaft based on a position where the distortion signal detected by the magnetic detection means is generated,
A steering angle detecting device, comprising: The magnetism detection means, after applying a current to the magnetostrictive wire, based on a time until a pressure wave generated in the magnetostrictive wire returns due to magnetic strain caused by a magnetic field generated from the magnet, 4. The steering angle detecting device according to claim 2, wherein a position where the distortion signal is generated is detected. The steering angle detecting device according to any one of claims 1 to 4, wherein the magnetostrictive wire is arranged in a spiral cable wound around the steering shaft.

Images