JPH10300595A - Torque sensor for steering gear for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electromagnetic induction-type torque sensor which is simplified, miniaturized and made lightweight, by reducing the number of detecting rings and detecting coils for the torque sensor. SOLUTION: The angle of rotation of an output shaft 32 is reduced more than the angle of rotation of an input shaft 31, and a bar 33 is twisted. Due to its twist, an area in which the teeth part 37 of a first detecting ring 35 is faced with the teeth part 38 of a second detecting ring 36 is changed. As a result, a magnetic flux which is passed through a coil 39 for torque detection is changed, also an induced voltage which is generated in the coil 39 is changed, and its voltage value is inputted to a signal processing part 41. In the processing part 41, the steering deviation between a steering handle 30 and a wheel is measured, a motive force part is moved, and the deviation is compensated. A measuring error due to a change in an ambient temperature is compensated in such a way that a signal which is inputted to a coil 40 for temperature compensation is removed in terms of a circuit. As a result, instead of three detecting rings which are required in conventional cases, two detecting rings can perform a function, and a torque sensor is not subjected to an influence due to an ambient temperature. The number of components can be reduced, and the interval between the first detecting rings 35 and the second detecting rings 36 can be set at one time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering apparatus for a vehicle, and more particularly to an electromagnetic induction type torque sensor, in which the number of detection rings and the number of detection coils are reduced to simplify the structure of the torque sensor. Accordingly, the present invention relates to a torque sensor for a vehicle steering device which can achieve a reduction in size and weight.

[0002]

2. Description of the Related Art Generally, an automobile is steered by rotating a steering wheel while a driver is running or stopping, whereby wheels in contact with a road surface are rotated. However, since the frictional force acts between the wheel and the road surface, the wheel does not rotate as much as the rotation angle of the steering wheel due to the loss during the power transmission process.

Therefore, it is necessary to measure and compensate for the difference in rotation angle between the steering wheel and the wheel. A device having such a function is a torque sensor. That is, the deviation of the rotation angle between the steering wheel and the wheel is measured through the torque sensor, and the wheel is rotated by a separate power means to the extent of the measured deviation. This allows the vehicle to:
The driver is steered exactly in the direction he wants to proceed.

As shown in FIGS. 11 and 12, a torque sensor of a conventional vehicle steering system having such a function includes an input shaft 2 having one end coupled to a steering handle 1.
And an output shaft 3 having one end coupled to the wheel side.
The input shaft 2 and the output shaft 3 are connected to each other, and a torsion bar 4 that is twisted according to the degree of steering is provided. At this time, one end of the torsion bar 4 is connected to the other end of the input shaft 2, and the other end of the torsion bar 4 is connected to the other end of the output shaft 3.

[0005] Between the input shaft 2 and the output shaft 3, there is provided a detection ring portion 5 comprising three detection rings 5A to 5C. These detection rings 5A to 5C are
The input shaft 2 and the output shaft 3 are made of a magnetic material and are disposed at a constant interval. Among them, the first detection ring 5A
Is connected to the outer peripheral surface of the input shaft 2 on the steering handle 1 side, and rotates by the same angle as the steering handle 1. Second
The detection ring 5B is coupled to the outer peripheral surface at the center of the torsion bar 4. The third detection ring 5C is coupled to the outer peripheral surface of the other end of the output shaft 3 connected to the wheel, and rotates by almost the same angle as the wheel.

On one surface of the first detection ring 5A, that is, on a surface facing the second detection ring 5B, a tooth portion 5D having an uneven shape is formed. Similarly, tooth portions 5E and 5F are formed on opposing surfaces of the second detection ring 5B and the third detection ring 5C, respectively. The first detection ring 5A and the second detection ring 5
The coils 6.7 are wound on the outer surface between the first detection ring B and the outer surface between the second detection ring 5B and the third detection ring 5C, respectively. These coils 6 and 7 are connected to a signal processing unit 8.

[0007] The operation of the torque sensor of the conventional vehicle steering system having the above-described structure is as follows. First, when the driver rotates the steering handle 1, the input shaft 2, the output shaft 3 and the torsion bar 4 also rotate. At this time, one end of the torsion bar 4 connected to the steering handle 1 is twisted more than the other end of the torsion bar 4 connected to the wheel, and rotates a lot. That is,
When the steering handle 1 is rotated, the rotation angle increases in the order of the first detection ring 5A> the second detection ring 5B> the third detection ring 5C due to the frictional force between the wheels and the road surface.

Therefore, the teeth 5 of the first detection ring 5A
D and the facing area of the second detection ring 5B hardly change, but in comparison with this, the tooth portion 5E of the second detection ring 5B
The opposing area between the first detection ring 5C and the tooth portion 5F of the third detection ring 5C changes. Accordingly, the outer magnetic flux between the second detection ring 5B and the third detection ring 5C changes, and the magnetic flux passing through the second coil 7 changes.

That is, the inductance values of the first coil 6 and the second coil 7 are set to be the same. The rotation of the steering handle 1 does not change the magnetic flux passing through the first coil 6, but changes the magnetic flux passing through the second coil 7. Thus, by measuring the change in the value of the induced electromotive force of the second coil 7 with respect to the induced electromotive force of the first coil 6, the rotational deviation between the steering wheel 1 and the wheels can be measured.

FIG. 13 is a block diagram of the signal processing section 8 of the conventional torque sensor. As shown in this figure, the signal processing unit 8 has a first clamp 11 and a third clamp 13 connected to an oscillator 9 through one side contact of a coil unit 10,
The second clamp 12 is connected to the other contact of the coil unit 10.
And the fourth clamp 14 are similarly connected to the oscillator 9.

The output terminals of the clamps 11 to 14 are connected to first to fourth peak detectors 15 to 18, respectively. A first differential amplifier 19 for detecting a difference between these outputs is connected to the output terminals of the first and second peak detectors 15 and 16. Similarly, the output terminals of the third and fourth peak detectors 17 and 18 have a second differential amplifier 20 for detecting a difference between these outputs.
Is connected. Further, a sub is output from the output terminal of the first differential amplifier 19 through the first current converter 21. Further, a main signal is output from the output terminal of the second differential amplifier 20 through the second current converter 22.

As described above, in the conventional signal processing configuration, the output of the oscillator 9 is input to each of the clamps 11 to 14 through the coil unit 10. Then, the first and second peak detectors 15 and 16 are output from the output signals of the first and second clamps 11 and 12 through the first differential amplifier 19.
Is detected. Also, the peak values of the third and fourth peak detectors 17 and 18 are detected from the output signals of the third and fourth clamps 13 and 14 through the second differential amplifier 20. The respective peak values can be transmitted as sub and main outputs through the first and second current converters 21 and 22.

[0013]

By the way, in the above-mentioned mechanical device and circuit configuration of the conventional torque sensor, when the torsion bar 4 is not twisted, the induced electromotive force generated in the coils 6 and 7 due to a change in ambient temperature. Must compensate. In the conventional torque sensor, as a configuration for compensating for the change in the surrounding temperature, the first detection ring 5A having the teeth 5D and the first coil 6 are used.

However, such a configuration requires many components for temperature compensation. Therefore, this torque sensor has a problem that the manufacturing cost is high and the size is large.

The signal processing unit 8 shown in FIG.
Because it is divided into two blocks, sub and main, for il safety processing, not only many parts are required, but also the signal must be raised to zero level or more for short power supply processing. Clamps 11-14
There was also a problem that it became necessary.

The present invention is intended to solve such conventional problems. A first object of the present invention is to provide only two detection rings, and provide a torque detection coil and a temperature compensation coil. To provide a torque sensor for a vehicle steering device in which the structure is simplified by winding.

A second object of the present invention is to install two detecting rings, install only a torque detecting coil, and use a temperature compensating diode for the signal processing means, so that the temperature detecting diode is not affected by the ambient temperature. It is an object of the present invention to provide a torque sensor for a vehicle steering device that can simplify the structure of the torque sensor.

A third object of the present invention is to install only two detecting rings, wind a torque detecting coil and a temperature compensating coil, improve the structure of the teeth (gear), and increase the facing area of the teeth. By measuring the change in the induced voltage due to the change in the steering wheel and the rotational deviation between the steering wheel and the wheel side,
Not only to simplify the structure of the torque sensor,
It is an object of the present invention to provide a torque sensor for a vehicle steering device in which the structure of a tooth portion of a detection ring facing the vehicle is improved.

[0019]

In order to achieve the first object, a torque sensor of a first vehicle steering apparatus according to the present invention includes an input shaft connected to a steering handle of a vehicle, and a wheel side. An output shaft, a torsion bar connecting the input shaft and the output shaft and twisting according to a steering degree, a detection ring installed between the input shaft and the output shaft, A torque detection coil wound around an outer portion between the first detection ring and the second detection ring to form a magnetic circuit; and a temperature compensation coil wound around an outer portion of the first detection ring to form a magnetic circuit. It is characterized by comprising a coil and signal processing means commonly connected to the coil.

According to the above configuration, the torque sensor of the vehicle steering system has only two detection rings, and the torque detection coil and the temperature compensation coil are wound. As a result, the structure can be simplified, and the cost can be reduced by reducing the number of parts. Further, the torque sensor of the vehicle steering device described above includes:
It is not affected by the ambient temperature.

In order to achieve the second object, a torque sensor for a second vehicle steering system according to the present invention includes an input shaft having one end connected to a steering handle of the vehicle, and the input shaft. The output shaft is separated at a fixed interval and one end is connected to the wheel side, one end is connected to the other end of the input shaft, and the other end is connected to the other end of the output shaft, , A torsion bar twisted by the steering motion of the steering handle, a first detection ring provided at the other end of the input shaft and having a tooth formed on one surface facing the output shaft, the other end of the output shaft A second detection ring provided on a portion and having a tooth portion formed on a surface facing one surface of the first detection ring; a magnetic circuit wound on an outer surface between the first detection ring and the second detection ring; Forming a detection coil, signal processing a voltage induced in the detection coil, It is characterized in that it comprises a signal processing means for compensating through temperature compensating means electromotive voltage.

According to the above configuration, the torque sensor of the vehicle steering system has two detection rings, only a torque detection coil, and a temperature compensating means. Have been. Thus, the torque sensor of the vehicle steering device has a simplified structure without being affected by the ambient temperature.

In order to achieve the third object, a torque sensor for a vehicle steering system according to a third aspect of the present invention is provided at the other end of the input shaft and is fixed to one surface facing the output shaft. A first detection ring having teeth formed by alternately forming short projections and long projections each having a length, and the other end of the output shaft, wherein the teeth are formed. A second detection ring having teeth formed on a surface facing one surface of the first detection ring; a short protrusion of the first detection ring;
A first detection coil wound on an outer surface between the protrusions of the detection ring to form a magnetic circuit; a winding on an outer surface between the long protrusion of the first detection ring and the teeth of the second detection ring; And a signal processing means connected to the first detection coil and the second detection coil for signal processing of a voltage induced in each of the detection coils. I have.

According to the above arrangement, only two detection rings are provided on the torque sensor of the vehicle steering system.
And the second detection coil is wound. Then, the structure of the teeth facing the detection ring has been improved, and by measuring the change in the induced voltage due to the change in the facing area of the teeth, the rotational deviation between the steering wheel and the wheel side is measured. Has become. Thus, the structure of the torque sensor of the vehicle steering device is simplified, and the torque sensor is not affected by the ambient temperature.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment 1] Regarding a first embodiment of the present invention,
The details will be described below with reference to the drawings.
FIG. 1 is an explanatory diagram schematically showing a configuration of a torque sensor (hereinafter, referred to as the present torque sensor) and peripheral components of a vehicle steering system according to the present embodiment. FIG. 2 is an explanatory diagram showing, in an enlarged manner, a detection ring portion 34, which is a main portion of the present torque sensor, and its periphery.

As shown in these figures, the present torque sensor includes an input shaft 31 connected to a steering wheel 30 of a vehicle.
, An output shaft 32 connected to the wheel side, a torsion bar 33, a detection ring portion 34, and a torque detection coil 39.
, A temperature compensating coil 40, and a signal processing unit (signal processing means) 41.

The torsion bar 33 connects the input shaft 31 and the output shaft 32 and twists according to the degree of steering of the steering handle 30. The detection ring portion 34 includes a first detection ring 35 having a large number of uneven tooth portions 37, and a second detection ring 36 having an uneven tooth portion 38 formed so as to face the tooth portions 37. It is composed of These first detection ring 35 and second detection ring 36
The input shaft 31 and the output shaft 32 are magnetic materials formed outside the input shaft 31 and the output shaft 32, respectively.
It is rocked integrally with. Torque detection coil 3
Reference numeral 9 denotes a magnetic circuit which is wound around an outer portion between the first detection ring 35 and the second detection ring 36. The temperature compensation coil 40 is wound around the outside of the first detection ring 35 to form a magnetic circuit.
These coils 39 and 40 are commonly connected to a signal processing unit 41.

FIG. 3 is a block diagram showing a detailed configuration of the signal processing section 41 in the present torque sensor. As shown in this figure, the signal processing unit 41 includes an oscillator 42, a coil unit 43, peak detectors 44 and 45, a differential amplifier 46, a VI conversion unit 47, and a voltage offset unit 48. It is composed of

The coil section 43 is a bridge circuit including the torque detecting coil 39 and the temperature compensating coil 40 in FIG. The oscillator 42 is 3 kHz, V _PP 4 V
And generates an induced voltage in the coils 39 and 40 in proportion to their respective inductances. The peak detectors 44 and 45 are connected to the oscillator 42 through the coil unit 43 and include a precision rectifier circuit composed of an operational amplifier (OP-AMP), a diode (DIODE), and a capacitor (CAPACITOR). . And the peak detectors 44 and 45
Are designed to detect the peak values of the coils 39 and 40. This detection is performed by detecting the constant current wave output using the precision rectifier circuit described above. Differential amplifier 46
Detects the difference between the outputs of the peak detectors 44 and 45 and amplifies the difference to a predetermined level.
The VI converter 47 converts the output voltage of the differential amplifier 46 into a current and outputs the current. The voltage offset unit 48 is commonly connected to the oscillator 42, the differential amplifier 46, and the VI conversion unit 47, and applies a constant offset voltage thereto.

The operation of the torque sensor having the above configuration will be described below. First, when the driver turns the steering wheel 30 to change the direction while the vehicle is running, the input shaft 31, the torsion bar 33 and the output shaft 32 are turned.
, The wheels are steered to change the traveling direction of the vehicle.
At this time, when a steering force exceeding a certain level acts, the rotation angle of the output shaft 32 connected to the torsion bar 33 is changed by the frictional force between the wheels and the road surface, and the rotation angle of the input shaft 31 that rotates together with the steering handle 30. Further, the torsion bar 33 is twisted.

At this time, the torsion causes the tooth portions 37 of the first detection ring 35 and the tooth portions 38 of the second detection ring 36.
And the area of the surface opposite to changes. Therefore, the first detection ring 3
The magnetic flux passing through the torque detecting coil 39 provided on the outer surface of the fifth and second detecting rings 36 changes, and the induced voltage generated in the torque detecting coil 39 changes at the same time. And
The induced voltage value changed by the change of the magnetic flux passing through the torque detecting coil 39 is input to the signal processing unit 41.

The signal processing section 41 measures the steering deviation between the steering handle 30 and the wheels based on the input signal, and moves a power section (both not shown) through an output section. Compensate for deviations.

On the other hand, a measurement error due to a change in the ambient temperature is compensated by removing the signal input to the temperature compensation coil 40 in a circuit. That is, since the temperature of the torque detecting coil 39 and the temperature of the temperature compensating coil 40 are the same, the voltages induced in the coils 39 and 40 due to changes in the ambient temperature become equal. Further, no induced voltage is generated in the temperature compensating coil 40 due to a steering deviation between the steering wheel 30 and the wheels. Therefore, by subtracting the voltage induced in the temperature compensation coil 40 in the differential amplifier 46 from the voltage induced in the torque detection coil 39, an induced voltage due to only the steering deviation, which is not affected by the temperature change, is obtained. be able to.

As shown in FIG. 3, the voltage offset unit 48 applies an offset voltage to the oscillator 42, the coil unit 43, the peak detectors 44 and 45, the differential amplifier 46, and the VI conversion unit 47. I have. This allows Fail Safet
There is no need to split the signal into two parts for processing. That is, the voltage induced in the coils 39 and 40 oscillates based on the offset voltage (SWIN
G), the process of level shifting becomes unnecessary, and the process of AD conversion is reduced to one stage. Therefore, it is possible to generate an output for distinguishing between a short (0 V), open (2.5 V), and normal (5 V) states.
This output can be applied to Fail Safety. The classification of these states is determined by a sensing circuit and an electronic control unit (ECU) (both not shown).

Embodiment 2 The second embodiment of the present invention will be described in detail with reference to the drawings. FIG. 4 is an explanatory diagram showing a torque sensor (hereinafter, referred to as the present torque sensor) of the vehicle steering system according to the present embodiment and a configuration around the torque sensor. As shown in this figure, the present torque sensor includes an input shaft 31 having one end coupled to a steering handle 30 of a vehicle, an output shaft 32 having one end coupled to a wheel side, and a torsion bar. 33,
It includes a detection ring section 34, a torque detection coil 39, and a signal processing section (signal processing means) 49.

Both ends of the torsion bar 33 are connected to the input shaft 3
1 and the other end of the output shaft 32, and are connected so that the end faces of the input shaft 31 and the output shaft 32 are separated at a predetermined interval. Detection ring 3
Reference numeral 4 denotes a first detection ring 35 made of a magnetic material having a large number of uneven teeth 37, and a first detection ring 35 made of a magnetic material having uneven teeth 38 facing the teeth 37. And two detection rings 36. This first
The detection ring 35 and the second detection ring 36 are formed on the outer peripheral surfaces of the other ends of the input shaft 31 and the output shaft 32, respectively, and swing together with the input shaft 31 and the output shaft 32.

The torque detecting coil 39 is wound around an outer portion between the first detecting ring 35 having the teeth 37 and the second detecting ring 36 having the teeth 38 to form a magnetic circuit. Is what it is. The coil 39 is electrically connected to a signal processing unit 49.

FIG. 5 is a block diagram showing a circuit configuration of the signal processing section 49 in the present torque sensor. As shown in this figure, the signal processing unit 49 includes an AC / DC conversion unit 50,
A first amplifying section 51, a temperature compensating section (temperature compensating means) 52, a second amplifying section 53, and a VI converting section 54 are provided.

The AC / DC converter 50 is connected to the above-described torque detecting coil 39, and converts a voltage induced by a change in magnetic flux passing through the torque detecting coil 39 into a DC voltage and outputs the DC voltage. It is. This AC / DC
The DC voltage output from the converter 50 varies depending on the temperature of the torque detection coil 39 (for example, 0.2 mV /
℃) voltage. The first amplifying unit 51 amplifies this voltage to a predetermined level (for example, 10 times) and outputs it.

The temperature compensator 52 has a power supply Vcc, resistors Ra to Rd, and a diode D. And
The voltage output from the diode D is, for example, −2 mV /
° C, the voltage of the power supply Vcc and the resistances Ra to Rd
And the resistance versus temperature characteristics of the diode D are selected. The output voltage from the diode D attenuates the component due to the temperature change from the voltage output from the first amplifying unit 51 and outputs the component to the second amplifying unit 53.

The second amplifying section 53 amplifies the voltage output from the temperature compensating section 52 to a predetermined level and outputs the amplified voltage as a voltage signal. The VI converter 54 converts the voltage signal output from the second amplifier 53 into a current signal and outputs the current signal to a power unit (not shown). The signal processing unit 49 includes an oscillator (not shown) similar to the oscillator 42 in the torque sensor described in the first embodiment.
z, it is oscillating a constant current wave of V _pp 4V.

The operation of the present torque sensor will be described below. In the present torque sensor, when the driver turns the steering wheel 30 to change the direction while the vehicle is running, the wheels are steered through the input shaft 31, the torsion bar 33, and the output shaft 32, and the running direction is changed. be changed. At this time, when a steering force exceeding a certain level is applied, the rotation angle of the output shaft 32 connected to the torsion bar 33 is rotated by the frictional force between the wheels and the road surface. The angle decreases from the angle, and the torsion bar 33 is twisted. For this reason, the facing area of the tooth portion 37 of the first detection ring 35 and the tooth portion 38 of the second detection ring 36 changes, so that the teeth are provided on the outer surfaces of the first detection ring 35 and the second detection ring 36. The magnetic flux passing through the torque detecting coil 39 changes, and the voltage induced in the torque detecting coil 39 also changes at the same time.

The signal of the induced voltage changed by the change of the magnetic flux passing through the torque detecting coil 39 is input to the signal processing unit 49. In the signal processing unit 49, AC
The / DC converter 50 converts the input induced voltage signal into a DC voltage signal and outputs the DC voltage signal to the first amplifier 51. This A
The DC voltage output from the C / DC converter 50 is a voltage that varies with temperature (for example, 0.2 mV / ° C.).
The first amplifier 51 converts this voltage to a predetermined level (for example, 1
0 times) and output. Then, the voltage output from the first amplifier 51 is input to the temperature compensator 52.

FIG. 6A shows the relationship between the ambient temperature and the output voltage from the first amplifier 51. As shown in this figure, the voltage output from the first amplifier 51 increases with temperature. FIG. 6B is a graph showing the relationship between the output voltage from the temperature compensator 52 and the temperature. Since the resistance of the diode D in the temperature compensator 52 changes depending on the temperature, the output voltage from the diode D depends on the temperature as shown in this graph.

Accordingly, the first amplifying section 51 to the temperature compensating section 5
The voltage input to 2 cancels (decays) the temperature change by the output voltage from the diode D. Therefore, when the torsion bar 33 is not twisted, the second amplifying unit 5
The voltage input to 3 becomes constant as shown in FIG. Therefore, the voltage input to the second amplification unit 53 is a voltage from which the influence of the change in the ambient temperature has been removed, that is, the torque detection coil 3
9 is a voltage of only the component induced (pure output voltage).

That is, if the relationship between the induced voltage of the torque detecting coil 39 and the temperature is 0.2 mV / ° C., the relationship between the induced voltage and the temperature amplified by, for example, 10 times in the first amplifying unit 51. Is 2 mV / ° C. Therefore, the power supply Vcc, the resistors Ra to Rd, and the resistance versus temperature characteristics of the diode D are selected so that the relationship between the output voltage from the diode D and the temperature in the temperature compensating unit 52 becomes −2 mV / ° C. By configuring the compensator 52, it is possible to compensate for the output voltage of the torque detection coil 39 that has changed due to the ambient temperature.

Thereafter, the pure voltage signal amplified and output by the second amplifier 53 is converted to a current signal by the VI converter 54 and output. Using this current signal, a measuring unit (not shown) measures the steering deviation of the rotation angle between the steering wheel 30 and the wheel, and based on the measurement result, a driving unit and a power unit (both not shown). ) Steers the wheels. As a result, the above-described rotational deviation can be compensated, so that the driver can steer the vehicle safely.

As described above, since the present torque sensor is provided with the temperature compensating section 52, even if only one torque detecting coil 39 is provided as the detecting coil,
It is possible to compensate for a steering deviation between the steering wheel 30 and the wheel and to compensate for a measurement error due to a change in ambient temperature.

The present torque sensor has an input shaft and an output shaft connected via a torsion bar, and a tooth portion formed on the other surface of the input shaft facing the output shaft. A first detection ring, a second detection ring provided at the other end of the output shaft and having a tooth formed on a surface facing one surface of the first detection ring, and the first and second detection rings. A detection coil that is wound on an outer surface between the first and second detection rings and electromagnetically coupled to the first and second detection rings to form a magnetic circuit; and a voltage that is electrically connected to the detection coil and is induced in the detection coil. And an AC / DC converter connected to a detection coil and converting a voltage induced by a change in inductance into a DC voltage. ,
A first amplifier for amplifying a voltage based on temperature included in the DC voltage converted from the AC / DC converter to a predetermined level; and an output voltage of a detection coil amplified from the first amplifier. A temperature compensating unit that attenuates a voltage due to a temperature rise, a second amplifying unit that amplifies only a pure output voltage induced in the detection coil output from the temperature compensating unit to a predetermined level, and a second amplifying unit. And a VI converter for converting the output voltage into a current.

Third Embodiment A third embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 7 is an explanatory diagram showing a configuration of a torque sensor (hereinafter, referred to as the present torque sensor) of the vehicle steering device according to the present embodiment and its surroundings. As shown in this figure, the present torque sensor includes an input shaft 31 having one end coupled to a steering handle 30 of a vehicle, an output shaft 32 having one end coupled to a wheel side, and a torsion bar. 33, a detection ring section 74, a first detection coil 80, a second detection coil 79, and a signal processing section (signal processing means) 55.

Both ends of the torsion bar 33 are connected to the input shaft 3
1 and the other end of the output shaft 32, and are connected so that the end faces of the other end of the input shaft 31 and the output shaft 32 are separated at a predetermined interval.

The detection ring portion 74 is provided between the input shaft 31 and the output shaft 32, and includes a first detection ring 75 and a second detection ring 76 both made of a magnetic material. The first detection ring 75 and the second detection ring 76 are formed on the outer peripheral surfaces of the other ends of the input shaft 31 and the output shaft 32, respectively, and swing together with the input shaft 31 and the output shaft 32.

The first detection ring 75 has an output shaft 3
On the surface facing 2, a tooth portion is provided in which a number of short protrusions 77 having a fixed length and long protrusions 77 </ b> A are alternately formed. Similarly, the second detection ring 7
6, a long protrusion 78A is formed so as to correspond to the short protrusion 77 of the first detection ring 75. Further, in the second detection ring 76, cutouts 76A are formed on both side surfaces of the lower end of the long protrusion 78A. The cutout 76A is provided to equalize the tendency (slope) of the detection site and the temperature compensation side due to temperature. Here, the detection site is a short protrusion 77 on the first detection ring 75 and a long protrusion 78 on the second detection ring 76.
A is a part facing. In addition, the temperature compensation side refers to a long protruding portion 77A of the first detection ring 75,
The portion of the second detection ring 76 that is not the long protruding portion 78A is a portion facing the second detection ring 76. The incision 76A is
First and second detection rings 75 and 76 covered by detection coil 79
Are provided so as to have the same area.

The first detection coil 80 is connected to the first detection ring 7
5 is a magnetic circuit wound around the outer side between the short protrusion 77 of the fifth and the long protrusion 78A of the second detection ring 76. The second detection coil 79 includes a long protrusion 77A of the first detection ring 75 and a long protrusion 78A of the second detection ring 76.
The magnetic circuit is wound on the outer part between the other parts. These detection coils 79 and 80 are electrically connected to the signal processing unit 55, respectively.

FIG. 8 is a block diagram showing a circuit configuration of the signal processing unit 55. As shown in FIG.
Includes an oscillation unit 60, a phase delay unit 61, a coil unit 62, a differential amplifier 64, and a VI conversion unit 65.

The coil section 62 includes a first resistor R1, a second resistor R2, and the above-described first detection coil 80 and second detection coil 79. Oscillator section 60, the offset voltage 3.5 V, is intended to oscillate 3 kHz, a constant current wave of V _pp 4V. The phase delay section 61 is connected to a contact point between the first resistor R1 and the first detection coil 80, and delays the phase of the output of the oscillation section 60 by a predetermined time. The differential amplifier 64 is connected to a contact point between the first resistor R1 and the second resistor R2 and a contact point between the first detection coil 80 and the second detection coil 79.

The differential amplifier 64 detects a difference between the voltages output from these two contacts, thereby detecting a difference between the voltages induced in the first detection coil 80 and the second detection coil 79, and detects the difference. The signal is amplified to a predetermined level and output. The VI conversion unit 65 converts the voltage signal output from the differential amplifier 64 into a current signal and outputs the current signal, drives a power unit (not shown) to steer the wheels, and safely steers the vehicle. It is.

The operation of the present torque sensor will be described below. In the present torque sensor, when the driver turns the steering wheel 30 to change the direction while the vehicle is running, the input shaft 31, the torsion bar 33, and the output shaft 3
The wheels are steered through 2 to change the running direction. At this time, when a steering force exceeding a certain level is applied, the rotation angle of the output shaft 32 connected to the torsion bar 33 is rotated by the frictional force between the wheels and the road surface. Decrease from angle, torsion bar 3
3 twists.

At this time, the facing area between the long protruding portion 77A of the first detecting ring 75 and the portion other than the long protruding portion 78A of the second detecting ring 76 does not substantially change, so that the second protruding portions provided on their outer surfaces are not changed. The induced voltage of the detection coil 79 does not change.

On the other hand, the torsion of the torsion bar 33 changes the facing area between the short projection 77 of the first detection ring 75 and the long projection 78 A of the second detection ring 76, and is induced by the first detection coil 80. Voltage changes.

Therefore, the magnetic flux passing through the second detection coil 79 does not change due to the rotation of the steering handle 30, and only the magnetic flux passing through the first detection coil 80 changes. Therefore, if the change in the voltage induced in the first detection coil 80 with respect to the voltage induced in the second detection coil 79 is measured in the signal processing unit 55, the rotational deviation between the steering wheel 30 and the wheel can be measured. Can be.

At this time, due to the cutouts 76A formed on both sides of the long protruding portion 78A of the second detection ring 76, the temperature-dependent tendency (inclination) between the detection site and the temperature compensation side becomes similar.

FIGS. 9A to 9D show the torsion bar 3.
When 3 is not twisted, the oscillation section 60 and the phase delay section 6
1 is a graph showing signals generated from members of a differential amplifier 64 and a VI conversion unit 65. FIG.
(A)-(d) is a graph which shows the signal which generate | occur | produces from each said member when the torsion bar 33 is twisted.

Initially, the output of the oscillating unit 60 as shown in FIG. 9A is delayed for a predetermined time by the phase delay unit 61, and becomes a signal as shown in FIG. It is input to the coil 80. On the other hand, the output of the oscillation section 60 is directly input to the second detection coil 79. Therefore,
When the torsion bar 33 is not twisted, the output value of the first detection coil 80 and the output value of the second detection coil 79 are canceled out (phase decay), and the output from the differential amplifier 64 and the VI conversion unit 65 are output. The output is as shown in FIGS. 9C and 9D.

On the other hand, when the torsion bar 33 is twisted, as described above, the magnetic flux passing through the second detection coil 79 does not change, and only the magnetic flux passing through the first detection coil 80 changes. Therefore, the output of the first detection coil 80 input to the differential amplifier 64 has a different value from the output of the second detection coil 79 due to the change in the magnetic flux. Therefore, the output from the differential amplifier 64 is as shown in FIG. 10C, and the detection coil 8 generated in response to the torsion of the torsion bar 33
The output difference of 0.79 is amplified in a predetermined manner,
It is output to the -I conversion unit 65. The VI converter 65 converts this voltage signal into a current signal and outputs a signal as shown in FIG.

Using this current signal, a measuring unit (not shown) measures the steering deviation of the rotation angle between the steering handle 30 and the wheel, and based on the measurement result, the power unit (both are used) through the driving unit. (Not shown) is moved to steer the wheels, and the rotational deviation between the steering wheel 30 and the wheels is compensated. Thereby, the driver can steer the vehicle safely.

When the torsion bar 33 is twisted, the inductance of the second detection coil 79 is changed,
The voltage induced in the second detection coil 79 may be changed.

[0068]

As described above, the torque sensor for a vehicle steering system according to the present invention uses only two detection rings, which were conventionally required three, and can be used as a torque sensor for a vehicle steering system. Functions can be performed. Further, the torque sensor of the vehicle steering system according to the present invention is not affected by the ambient temperature. As a result, the cost can be saved by reducing the number of parts, and the fixed interval between the first detection ring and the second detection ring can be set at one time, so that the structure can be simplified. be able to.

In the torque sensor for a vehicle steering system according to the present invention, an offset is added to an oscillator, an amplifier, and a current converter. Therefore, no separate clamping process is required. Further, it is possible to obtain a signal for monitoring a sensor state such as a short circuit, an open circuit, and a normal circuit.

By compensating for a measurement error due to a change in ambient temperature using the voltage characteristics of the diode, accurate steering deviation can be measured and temperature compensation can be performed even when the ambient temperature changes.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of a torque sensor of a vehicle steering system according to a first embodiment of the present invention and a configuration around the torque sensor;

FIG. 2 is an explanatory diagram showing an enlarged view of a detection ring portion, which is a main portion of the torque sensor of the vehicle steering system shown in FIG.

FIG. 3 is a block diagram showing a configuration of a signal processing unit in the torque sensor of the vehicle steering system shown in FIG.

FIG. 4 is an explanatory diagram showing a configuration of a torque sensor of a vehicle steering system according to a second embodiment of the present invention and a configuration around the torque sensor;

5 is a block diagram illustrating a circuit configuration of a signal processing unit in the torque sensor of the vehicle steering system shown in FIG.

6 (a) is a graph showing a relationship between an output voltage from a first amplifier and an ambient temperature in a torque sensor of the vehicle steering system shown in FIG. 4, and FIG. 6 (b). Figure 4
FIG. 6C is a graph showing the relationship between the output voltage from the temperature compensator and the ambient temperature in the torque sensor of the vehicle steering system shown in FIG. 4 is a graph showing a voltage input to a second amplifier and a surrounding temperature in a torque sensor of the vehicle steering device shown in FIG.

FIG. 7 is an explanatory diagram illustrating a configuration of a torque sensor of a vehicle steering system according to a third embodiment of the present invention and a configuration around the torque sensor;

FIG. 8 is a block diagram illustrating a circuit configuration of a signal processing unit in the torque sensor of the vehicle steering system shown in FIG. 7;

FIG. 9A is a graph showing a signal waveform output by an oscillation unit in the signal processing unit shown in FIG. 7 when the torsion bar is not twisted, and FIG. 9C is a graph illustrating a signal waveform output from the phase delay unit, FIG. 9C is a graph illustrating a signal waveform output from the differential amplifier, and FIG. 9D is a graph illustrating the VI conversion unit. 4 is a graph showing a signal waveform to be output.

10A is a graph showing a signal waveform output from an oscillation unit in the signal processing unit shown in FIG. 7 when the torsion bar is twisted, and FIG.
FIG. 10C is a graph showing a signal waveform output from the phase delay unit, FIG. 10C is a graph showing a signal waveform output from the differential amplifier, and FIG. 5 is a graph illustrating a signal waveform output by a conversion unit.

FIG. 11 is an explanatory diagram showing a configuration of a conventional torque sensor of a vehicle steering system and its surroundings.

FIG. 12 is an explanatory diagram showing an enlarged view of a periphery of a detection ring which is a main part of the torque sensor of the vehicle steering system shown in FIG. 11;

FIG. 13 is a block diagram illustrating a configuration of a signal processing unit of a torque sensor of the vehicle steering system shown in FIG. 11;

[Explanation of symbols]

 Reference Signs List 30 steering handle 31 input shaft 32 output shaft 33 torsion bar 34, 74 detection ring part 35, 75 first detection ring 36, 76 second detection ring 37, 38 tooth part 39 torque detection coil 40 temperature compensation coil 41, 49, 55 Signal processing unit (signal processing means) 44, 45 Peak detector 46, 64 Differential amplifier 47, 54, 65 VI conversion unit 48 Voltage offset unit 50 AC / DC conversion unit 51 First amplification unit 52 Temperature Compensation section (temperature compensation means) 53 Second amplification section 77 Short projection section 77A, 78A Long projection section 79 Second detection coil 80 First detection coil

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Gaku Hyun, Han Republic of Korea, Gyeonggi-do, Namyangju-si, Wab-Eub, Duxoli 95

Claims (8)

[Claims] An input shaft and an output shaft connected via a torsion bar, and a first detection ring provided at the other end of the input shaft and having a tooth portion formed on one surface facing the output shaft. A second detection ring provided at the other end of the output shaft and having a tooth portion formed on a surface facing one surface of the first detection ring; and an outer side between the first and second detection rings. A torque detection coil that is wound around and electromagnetically coupled to the first and second detection rings to form a magnetic circuit; and a coil that is wound outside the second detection ring and electromagnetically coupled to the second detection ring. A temperature compensating coil forming a circuit; and a signal processing means connected to the torque detecting coil and the temperature compensating coil to perform electrical control. Torque sensor. 2. The signal processing means according to claim 1, wherein said signal processing means is connected to an oscillator through a coil section forming a bridge circuit, and detects a peak value. A differential amplifier for amplifying, and a current converter for converting an output voltage of the differential amplifier into a current, wherein a voltage offset unit is commonly connected to the oscillator, the differential amplifier, and the current converter. The torque sensor for a vehicle steering system according to claim 1, wherein: 3. An input shaft and an output shaft connected via a torsion bar, and a first detection ring provided at the other end of the input shaft and having a tooth portion formed on one surface facing the output shaft. A second detection ring provided at the other end of the output shaft and having a tooth portion formed on a surface facing one surface of the first detection ring; and an outer portion between the first and second detection rings. It is wound on the side,
A detection coil that is electromagnetically coupled to the first and second detection rings to form a magnetic circuit; and a signal processing that is electrically connected to the detection coil and performs signal processing on a voltage induced in the detection coil to perform temperature compensation. And a torque sensor for a vehicle steering system. 4. An AC / DC converter, wherein said signal processing means is connected to a detection coil and converts a voltage induced by a change in magnetic flux passing through the detection coil into a DC voltage. A first amplifier for amplifying a voltage based on temperature included in the DC voltage converted from the converter to a predetermined level; and a voltage due to a temperature increase included in the output voltage of the detection coil amplified from the first amplifier. Temperature amplifying means for amplifying only a pure output voltage induced in the detection coil outputted from the temperature compensating means to a predetermined level, and a voltage outputted from the second amplifying part. To convert to V
4. An I-to-I conversion unit.
A torque sensor for a vehicle steering system according to any of the preceding claims. 5. A torque sensor for a vehicle steering system according to claim 4, wherein said temperature compensating means comprises a diode whose voltage characteristic with respect to temperature is negative (-). 6. An input shaft and an output shaft connected to each other with a torsion bar interposed therebetween, and a short protrusion provided on the other end of the input shaft and having a predetermined length on one surface facing the output shaft. A first detection ring formed with teeth having alternately formed long protrusions; and a long protrusion provided on the other end of the load shaft and facing one surface of the first detection ring alternately. A second detection ring on which a configured tooth portion is formed; and an outer surface between a short protrusion of the first detection ring and a long protrusion of the second detection ring; A first detection coil electromagnetically coupled to the ring to form a magnetic circuit; and a first detection coil wound on an outer surface between a long protrusion of the first detection ring and a tooth of the second detection ring. A second detection coil electromagnetically coupled to the ring to form a magnetic circuit; 1, the torque sensor of the vehicle steering apparatus being characterized in that is composed of a signal processing means for processing the signal by the voltage induced in the respective detection coils are connected to the second detection coil. 7. A cut-out portion is formed at a lower end portion on both sides of the long projecting portion of the second detection ring so as to make the detection portion and the temperature compensation side have the same inclination with respect to temperature. A torque sensor for a vehicle steering system according to any of the preceding claims. 8. A phase delay section connected to a contact point between the first resistor and the first detection coil and delaying the phase of the oscillating section for a predetermined time, the signal processing means includes: a contact point between the first and second resistors; 1, a differential amplifier connected to the contact point of the second detection coil to detect an output difference and then amplify the output difference to a predetermined level; and a VI converter for converting an output voltage of the differential amplifier into a current and outputting the current. 7. A torque sensor for a vehicle steering system according to claim 6, comprising: