KR100458192B1 - detection apparatus for steering angle in vehicle - Google Patents

Abstract

The present invention relates to a steering angle detection device for a vehicle which can reduce the minimum detection angle and further accurately detect the current steering angle even if the power is cut off and returned.

The steering angle detecting apparatus for a vehicle of the present invention includes a shaft gear inserted outside the steering shaft of the vehicle; A first transducer gear toothed to the shaft gear at a predetermined gear ratio; A second transducer gear coaxially coupled to the first transducer gear and having a predetermined number of teeth; A third converter gear meshed with the second converter gear at a predetermined gear ratio; A fourth transducer gear engaged with the third transducer gear at a predetermined gear ratio; A fifth transducer gear coaxially coupled with the fourth transducer gear and having a predetermined number of teeth; A detector gear engaged with the fifth converter gear at a predetermined gear ratio; A permanent magnet installed on the axis of the detector and generating a rotating magnetic field; And a calculation / control means for calculating the rotation direction and the rotation angle of the steering shaft by calculating and processing a magnetoresistive sensor provided near the upper part of the permanent magnet and a detection signal provided from the magnetoresistive sensor by a predetermined program.

Description

Detection apparatus for steering angle in vehicle

The present invention relates to an apparatus for detecting a steering angle of a vehicle, and more particularly, to an apparatus for detecting a steering angle of a vehicle implemented using a magnetoresistive sensor.

Various devices capable of detecting the rotation angle of the rotating body have been proposed. Such a rotation angle detection device can be used, for example, in a steering angle detection device of a vehicle. In more detail, in the vehicle, a steering angle detection device is adopted to perform roll suppression during steering in performing damping force control of the shock absorber, and so on. FIG. 1 illustrates a structure of a conventional steering angle detection device of a vehicle. 2A and 2B are diagrams showing detection waveforms at the time of turning right and left at the apparatus of FIG. 1, respectively. As shown in FIG. 1, in a conventional steering angle detection apparatus of a vehicle, a slit disc 14 is inserted outside the steering shaft 11, and a plurality of slits 12 are formed on concentric circles of the edge of the slit disc 14. It is drilled at equal intervals. On the other hand, two pairs of photo interrupts 16 and 17 made up of light receiving elements and light emitting elements respectively disposed on both sides with the slit disc 14 interposed therebetween are fixed to a steering column tube (not shown).

In the above-described configuration, when the slit 12 is positioned between the light emitting element and the light receiving element of the photo interrupts 16 and 17 as the steering shaft 11 rotates, the light generated by the light emitting element is transmitted to the light receiving element. On the contrary, when the slit periphery is positioned, on / off pulses are generated in the light receiving element whenever the steering angle is 9 ° due to the principle that light generated in the light emitting element is not transmitted to the light receiving element. Furthermore, a phase difference of 4.5 ° is made between the two pairs of photo interrupts 16 and 17 to determine the rotational direction of the steering shaft 11. That is, as shown in FIG. 2A, when the signal state of one photo interrupt 16 rises, if the signal state of the other photo interrupt 17 is high (H) level, it is determined to turn right. On the contrary, as shown in FIG. 2B. If it is the low level L, it is discriminated as turning left.

In FIG. 1, reference numeral 13 denotes a neutral point detecting slit of the steering shaft 11, and 15 denotes a photo interrupt for detecting whether the neutral point detecting slit 11 passes.

However, according to the conventional steering angle detection apparatus of the vehicle as described above, the minimum detection angle is determined because the interval of each slit is determined in consideration of the detection resolution of the photo interrupt in a state in which the slit disc cannot be enlarged indefinitely due to the limitation of the installation space. There is a problem that can not be made small.

In particular, in the conventional apparatus, since the steering angle is calculated in a relative manner based on the number of pull signals counted from the point of time when the neutral point signal is input, when the power is cut off for some reason, the power is turned on again within a short time. Since the count values are all erased, there is a problem in that the steering angle state of the current vehicle cannot be determined at all.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a steering angle detection apparatus for a vehicle that can make a minimum detection angle small and further accurately detect the current steering angle even when the power is cut off and returned. There is a purpose.

Steering angle detection apparatus for a vehicle of the present invention for achieving the above object is a shaft gear inserted to the outside of the steering shaft of the vehicle; A first transducer gear toothed to the shaft gear at a predetermined gear ratio; A second transducer gear coaxially coupled to the first transducer gear and having a predetermined number of teeth; A third converter gear meshed with the second converter gear at a predetermined gear ratio; A fourth transducer gear engaged with the third transducer gear at a predetermined gear ratio; A fifth transducer gear coaxially coupled with the fourth transducer gear and having a predetermined number of teeth; A detector gear engaged with the fifth converter gear at a predetermined gear ratio; A permanent magnet installed on the axis of the detector and generating a rotating magnetic field; And a calculation / control means for calculating the rotation direction and the rotation angle of the steering shaft by calculating and processing a magnetoresistive sensor provided near the upper part of the permanent magnet and a detection signal provided from the magnetoresistive sensor by a predetermined program.

1 is a perspective view for explaining the structure of a conventional steering angle detection apparatus of a vehicle,

2A and 2B show detection waveforms at the right turn and the left turn, respectively, in the apparatus of FIG. 1;

3 is a view for explaining the detection principle of the magnetoresistive sensor used in the steering angle detection device of a vehicle according to an embodiment of the present invention;

4 is a detection output waveform diagram of a magnetoresistive sensor;

5 is a plan view schematically showing the mechanical configuration of a steering angle detection device of a vehicle of the present invention;

6 is a schematic cross-sectional view taken along line A-A of FIG. 5;

7 is an electrical block diagram of an apparatus for detecting a steering angle of a vehicle according to the present invention;

8 is a graph showing a displacement relationship between the gears in the configuration shown in FIG.

*** Explanation of symbols for the main parts of the drawing ***

20: magnetoresistive sensor, 22, 24: bridge element,

40: steering shaft, 50: shaft gear,

52: first translator gear, 54: second translator gear,

56: third converter gear, 57: fourth converter gear,

58: fifth transducer word, 59: detector word,

59a: support ribs, 59b: magnetic seat,

60: permanent magnet, 70: printed circuit board,

80: housing, 90: A / D converter,

100: operation / control unit

Hereinafter, a steering angle detecting apparatus for a vehicle according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a view illustrating a detection principle of a magnetoresistive sensor used in a steering angle detection apparatus of a vehicle according to a preferred embodiment of the present invention, and FIG. 4 is a detection output waveform diagram of the magnetoresistive sensor. As shown in FIG. 3, when an external rotating magnetic field B is applied to the magnetoresistive sensor 20 having two magnetoresistive bridge elements 22 and 24 arranged to be turned by 45 ° from each other. In the output terminals U1 and U2 of the bridge elements 22 and 24, as shown in FIG. 4, two sinusoidal signals VU1 and VU2 having a period of 180 degrees and a phase difference of 45 degrees are generated. Will be obtained. At this time, if the amplitudes of the sinusoidal signals VU1 and VU2 are the same, the current angle θ of the external rotating magnetic field B can be calculated by the following equation (1).

As the magnetoresistive sensor described above, an anisotropic magneto resistive sensor made of a permalloy (registered trademark) thin film, which is a kind of iron and nickel alloys, may be preferably used. In Fig. 3, reference signs Vcc1 and Vcc2 denote power supply voltages applied to the bridge elements 22 and 24, respectively, and + Vo1 and -Vo1 denote the positive output voltage and the negative output voltage of the bridge element 22, respectively. + Vo2 and -Vo1 represent the positive output voltage and the negative output voltage of the bridge element 24, respectively.

FIG. 5 is a plan view schematically illustrating a mechanical configuration of a steering angle detection device of a vehicle of the present invention, and FIG. 6 is a schematic cross-sectional view taken along line A-A of FIG. 5.

As shown in Figs. 5 and 6, the mechanical configuration of the steering angle detection device of the vehicle of the present invention is a housing 80 in which the device is housed, a shaft gear 50 inserted outside the steering shaft 40 of the vehicle. , The second converter gear 54 coaxially coupled to the first converter gear 52 and the first converter gear 52 which are tooth-coupled with the shaft gear 50 at a predetermined gear ratio, and having a predetermined number of teeth, and the second conversion. Third transducer gear 56, which is engaged with the gear 54 at a predetermined gear ratio, fourth transducer gear 57, and fourth transducer gear 57, which is engaged with the third transducer gear 56 at a predetermined gear ratio. And coaxially coupled with and mounted on a shaft of a fifth transducer gear 58 having a predetermined number of teeth, a fifth detector gear 58 having a predetermined gear ratio, and a detector gear 59 coupled with a predetermined gear ratio. To support the magnetoresistance sensor 20 and the magnetoresistance sensor 20 which are installed in the upper part of the permanent magnet 60 and the permanent magnet 60 to generate a rotating magnetic field, and also detect other It can be performed by an electrical circuit necessary for the value to include a substrate 70 with a printed circuit. In addition, in order to reduce the overall size of the detection device, it is preferable to implement the detector word 59 as an internal gear. In this case, the permanent magnet 60 is supported by the support rib 59a so that It can be mounted to the magnet seating portion 59b formed at the center.

In the above-described configuration, the teeth of each gear include 42 shaft gears 50, 28 first transducer gears 52, 14 second transducer gears 54, and 3rd transducer gears 56. There may be 16, the fourth transducer gear 57, the fifth transducer gear 58, the fourteen transducer gears 59, and the number of the detector gear 59 may be 50, which may be appropriately changed. In this case, when the shaft gear 50 is rotated four times, the first transducer gear 52 and the second transducer gear 54 make six revolutions (4 * 42/28), and the third transducer gear 54 ) Is 5.25 revolutions (6 * 14/16), the fourth transducer gear 57 and the fifth transducer gear (58) is 1.68 revolutions (5.25 * 16/50), and finally the detector gear ( 59 rotates 0.47 (1.68 * 14/50) so that the angular displacement during four rotations of the shaft gear 40 can be detected using one magnetoresistive sensor 20.

7 is an electrical block diagram of an apparatus for detecting a steering angle of a vehicle according to the present invention. As shown in FIG. 7, the electrical configuration of the steering angle detecting apparatus for a vehicle according to the present invention is a digital signal having a magnitude corresponding to the detection signal output from the magnetoresistive sensor 20 and the magnetoresistive sensor 20 in analog form, respectively. The analog-to-digital (A / D) converter 90 and the digital detection signal output from the A / D converter 90 are processed by Equation 1, and then substituted into a predetermined conversion formula or table. Finally, the operation / control unit 100 may calculate the rotation direction and the rotation angle of the steering shaft 40.

In the above-described configuration, the operation / control unit 100 may be implemented as a microprocessor unit or dedicated control logic. The A / D converter 90 may be integrally provided in the microprocessor unit or implemented as a separate element.

8 is a graph showing a displacement relationship between the gears in the configuration shown in FIG. As shown in FIG. 8, the first transducer gear 52 is rotated by 540 ° while the shaft gear 50 is rotated by 360 °, and the detector gear 59 is rotated by approximately 45 °. As a result, the detector gear 59 rotates slightly less than half a turn while the shaft gear 50 makes four revolutions, and thus the rotation angle of the shaft gear 50, that is, the steering angle, is changed by one magnetoresistive sensor 20. It can be detected almost linearly.

Then, in accordance with such a relationship, the calculation / control unit 100 substitutes the detection angle obtained by the magnetoresistive sensor 20 into a conversion table based on Equation 2 below or Equation 2 obtained by substituting the aforementioned gear ratios. By this, the unknown rotation direction and rotation angle of the steering shaft 40 can be known.

In Equation 2 above, Denotes the rotation angle of the shaft gear 50, that is, the steering shaft 40, Denotes a rotation angle of the detector word 52 detected by the magnetoresistive sensor 20.

On the other hand, in the present invention, if the steering shaft, the phase between each gear, the phase of the permanent magnet and the magnetoresistance sensor is properly fixed during the manufacture of the vehicle, a separate neutral point detection means is not required, In consideration of the detection error may be further provided with a neutral point detection means as shown in Figure 1 may be to detect the neutral point.

The steering angle detection apparatus for a vehicle of the present invention is not limited to the above-described embodiments, and can be variously converted and implemented within the range allowed by the technical idea of the present invention. For example, in the above-described embodiment, it has been described that two bridge elements are included in the magnetoresistive sensor. However, the present invention is not limited thereto, and a known single bridge element or a resistor split type may be used.

According to the steering angle detection device of the vehicle of the present invention as described above, since the device is implemented using a magnetoresistive sensor having a higher resolution than the photo interrupt, the steering angle can be detected more precisely. Even if it is removed and returned, there is an effect that can accurately detect the current rotation angle of the steering shaft.

Claims (4)

A shaft gear inserted outside the steering shaft of the vehicle; A first transducer gear toothed to the shaft gear at a predetermined gear ratio; A second transducer gear coaxially coupled to the first transducer gear and having a predetermined number of teeth; A third converter gear meshed with the second converter gear at a predetermined gear ratio; A fourth transducer gear engaged with the third transducer gear at a predetermined gear ratio; A fifth transducer gear coaxially coupled with the fourth transducer gear and having a predetermined number of teeth; A detector gear engaged with the fifth converter gear at a predetermined gear ratio; A permanent magnet installed on the axis of the detector and generating a rotating magnetic field; Magnetoresistive sensor installed close to the upper part of the permanent magnet and And an arithmetic / control means for calculating a rotational direction and a rotational angle of a steering shaft by calculating and processing the detection signal provided from the magnetoresistive sensor by a predetermined program. 2. The steering angle detection apparatus for a vehicle according to claim 1, wherein the magnetoresistive sensor comprises an anisotropic magnetoresistive sensor. 3. The magnetoresistance sensor according to claim 1 or 2, wherein the magnetoresistive sensor comprises two bridge elements having a phase difference of 45 DEG from each other; The teeth of the shaft gear, the first transducer gear, the second transducer gear, the third transducer gear, the fourth transducer gear, the fifth transducer and the detector gear are 42, 28, 14, 16, 50, 14, respectively. And 50 spur gears. 4. The steering angle detection apparatus for a vehicle according to claim 3, wherein the detector gear comprises an internal gear having a magnet seating portion on which the permanent magnet is mounted and a support rib supporting the magnet seating portion at the center thereof.