JP2001074571A - Magneto-strictive torque sensor for detecting steering force - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit a steering condition in steering to plural peripheral devices different in frequency characteristics, by a single torque detecting circuit. SOLUTION: Plural torque signal output circuits 5B, 5C, 5D provided with low-pass filters 5b-1, 5c-1, 5d-1 which differ in frequency characteristics are connected in parallel in a downstream of a comparison circuit 4B of this magneto-striction type torque sensor 1 for detecting steering force, and steering condition in steering is thereby transmitted by a single torque detecting circuit 2 to plural peripheral devices different in frequency characteristics, i.e., a power steering controller, a car navigation system and meters. A torque signal output circuit 5A exclusive for the power steering controller of an important peripheral device is provided downstream of a comparison circuit 4A to enhance reliability for the operation of the power steering controller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improvement in a magnetostrictive torque sensor for detecting a steering force.

[0002]

2. Description of the Related Art A magnetostrictive torque sensor for detecting a steering force comprising a torque detection circuit, a rectifier circuit, a comparison circuit, a torque signal output circuit and the like is already known. It is widely used when detecting and inputting a control signal to a power steering controller.

[0003]

In a conventional magnetostrictive torque sensor for detecting a steering force, for example, a magnetostrictive torque sensor disclosed in Japanese Patent Application Laid-Open No. 2-195221, an oscillation excitation provided in a torque detection circuit is provided. The frequency characteristic of the final output from the torque sensor has been uniquely determined according to the oscillation frequency of the source.

[0004] For this reason, in consideration of matching of input and output of signals to and from a peripheral device requiring a final output from the magnetostrictive torque sensor for detecting a steering force, for example, a power steering controller, etc. It is necessary to determine the oscillation frequency of the oscillation excitation source according to the specifications.

However, in recent years, power steering systems
In addition to the controller, for example, some peripheral devices, such as a car navigation system, which need to receive the final output from the steering force detecting magnetostrictive torque sensor and grasp the steering state of the steering have been developed. As a result, various specifications of frequencies have been required for the final output of the magnetostrictive torque sensor for steering force detection.

Generally, for example, power steering
A frequency of about 500 Hz or less is suitable for a controller, a frequency of about 1 kHz or less for a car navigation system, and a frequency of about 100 Hz or less for meters and the like on an instrument panel. It is.

However, as described above, in the conventional magnetostrictive torque sensor for steering force detection, due to its structure, the frequency characteristic of the final output from the torque sensor is uniquely determined according to the oscillation frequency of the oscillation excitation source. Therefore, there arises a problem that a plurality of peripheral devices having different frequencies cannot be connected to one steering force detecting magnetostrictive torque sensor.

If a plurality of peripheral devices having different frequency characteristics are to be used at the same time, a plurality of torque detecting circuits having different frequency characteristics must be provided side by side, and the structure around the steering column becomes complicated. At the same time, the manufacturing cost of the device also increases significantly.

[0009]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide a steering force capable of transmitting a steering state to a plurality of peripheral devices having different frequency characteristics by a single torque detection circuit. An object of the present invention is to provide a magnetostrictive torque sensor for detection.

[0010]

SUMMARY OF THE INVENTION The present invention provides a torque detection circuit including an oscillation excitation source, a pair of magnetic anisotropic members, an excitation coil and a detection coil, and an electric signal output from each of the detection coils. A rectifying circuit portion including a pair of rectifying circuits for rectifying the electric current, a comparing circuit for obtaining a deviation of the electric signal output from the rectifying circuits and outputting the detected torque as a torque detection signal, and a predetermined torque detecting signal output from the comparing circuit. Torque signal output circuit having a low-pass filter for smoothing based on the frequency characteristics of the above and a gain / mid-point potential adjusting means for adjusting the mid-point potential of the output of the low-pass filter, multiplying by a predetermined gain, and outputting to a peripheral device A torque sensor having a low-pass filter having a different frequency characteristic on the downstream side of the comparison circuit. It has a configuration which is characterized in that to connect the signal output circuit in parallel to. A plurality of torque signal output circuits composed of a low-pass filter and a gain / midpoint potential adjusting means are arranged in parallel downstream of the comparison circuit, and the cut-off frequency characteristics of the low-pass filter of each torque signal output circuit are individually determined. To the frequency characteristics of the peripheral device. Since the oscillation frequency of the torque detection circuit located on the upstream side is sufficiently high at 20 kHz to 50 kHz, the cut-off frequency characteristic of the low-pass filter in each torque signal output circuit is set to each peripheral device having a lower frequency characteristic. Just set according to
One torque detection circuit can cope with peripheral devices having various frequency characteristics up to 50 kHz.

Also, a plurality of rectifier circuits are connected in parallel on the downstream side of the torque detection circuit, and at least one comparison circuit and a torque signal output circuit are provided at least downstream of one of the rectifier circuits. At the same time, a single comparison circuit and a plurality of torque signal output circuits each including a low-pass filter having a different frequency characteristic may be connected in parallel on the downstream side of the other rectification circuit unit. Good.

According to this configuration, the peripheral device requiring high reliability, for example, a power steering controller or the like is connected downstream of the sole comparison circuit and the torque signal output circuit to operate the peripheral device. Peripheral devices that ensure the stability of the vehicle and that do not directly affect the original functions and safety of the vehicle, such as
By connecting the navigation system and meters on the instrument panel in parallel with the downstream of the other torque signal output circuit, that is, downstream of the other rectifier circuit, the rectifier circuit and the comparator circuit are connected. The number can be minimized.

Further, the gain of the torque signal output circuit
An adjustment control circuit for setting the midpoint potential and the gain is provided in each of the midpoint potential adjusting means, and the midpoint potential and the midpoint potential adjusting means in each of the torque signal output circuits are provided by the adjusting control circuit. By configuring so as to set the gain, the characteristics of the gain / midpoint potential adjusting means provided in each of the plurality of torque signal output circuits can be controlled by one adjustment control circuit.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram schematically showing a main part of a circuit configuration of a magnetostrictive torque sensor 1 for detecting a steering force according to an embodiment of the present invention.

The magnetostrictive torque sensor 1 for steering force detection generally includes one torque detection circuit 2 and two sets of rectifications provided in parallel to rectify an electric signal output from the torque detection circuit 2. The circuit units 3A and 3B, and the only comparison circuit 4A and the torque signal output circuit 5A connected to the downstream side of one rectification circuit unit 3A, and one comparison circuit 4A connected to the downstream side of the other rectification circuit unit 3B. Comparison circuit 4B
And a plurality of torque signal output circuits 5B, 5C, 5D connected in parallel on the downstream side of the comparison circuit 4B, and one adjustment signal common to all of the torque signal output circuits 5A, 5B, 5C, 5D. It is constituted by a control circuit 6.

The torque detecting circuit 2 includes a pair of magnetic anisotropic members (see FIG. 1) which are obliquely mounted on the outer periphery of a steering shaft connected to the steering wheel at an angle of about 45 degrees with respect to the axis. (Not shown), and a pair of detection coils 7a, 7a,
7b, a torque detector 9 including a pair of excitation coils 8a, 8b provided corresponding to the detection coils 7a, 7b, respectively, and the excitation coils 8a, 8b of the torque detector 9.
An oscillation circuit 10 serving as an oscillation excitation source for exciting the signal and a buffer 11 are provided. Note that the oscillation frequency of the oscillation circuit 10 in this embodiment is about 50 kHz.

An excitation current is supplied to the excitation coils 8a and 8b via an oscillation circuit 10 as an oscillation excitation source and a buffer 11 constituting a current amplification circuit. Further, each of the detection coils 7a and 7b detects a small twist generated in the steering shaft due to the operation of the steering wheel as a change in the magnetic permeability of the magnetic anisotropic member, and outputs this as an electric signal.

The electric signals output from the detection coils 7a and 7b are rectified by a pair of rectification circuits 3a-1 and 3a-2 provided in one rectification circuit section 3A and input to the comparison circuit 4A. The rectification circuit 3b-1 and 3b-2 provided in the other rectification circuit unit 3B also rectify and input the same to the comparison circuit 4B.

The only comparison circuit 4A connected downstream of one rectification circuit section 3A is a rectification circuit 3a-
The deviation of the electric signal from the steering wheel 1, 3a-2, that is, the magnitude of the steering force acting on the steering wheel and the steering direction are obtained, and then the low-pass filter 5a-1 constituting a smoothing circuit in the torque signal output circuit 5A. Removes the influence of noise from this deviation, and outputs the torque signal output circuit 5A.
To the gain / midpoint potential adjusting means 5a-2.

The gain / midpoint potential adjusting means 5a-2 of the torque signal output circuit 5A absorbs a change in the characteristic of the sensitivity of the torque detector 9 due to a change in the environmental temperature, and reduces the operating force of the steering wheel by the driver. It has a gain adjustment function of adjusting the output gain so that an appropriate proportional torque signal Ts1 can be output, and the value of the output gain is controlled by a microprocessor provided in the control unit 12 of the adjustment control circuit 6.

The gain of the torque signal output circuit 5A
The midpoint potential adjusting means 5a-2 absorbs a voltage drift generated in the torque detector 9 due to a change in environmental temperature, and outputs a torque signal output circuit 5A when the substantial steering force acting on the steering wheel is "0". Has a mid-point potential adjusting function of adjusting the mid-point potential of the torque signal Ts1 so that the value of the torque signal Ts1 output from the control signal matches a predetermined set voltage. Control unit 1
2 controls the value of the midpoint potential.

The torque signal Ts1 output from the gain / midpoint potential adjusting means 5a-2 of the torque signal output circuit 5A is input as a power assist command to a power steering controller (not shown), and the power steering The controller uses the torque signal Ts
In step 1, the drive torque of the power assist motor is feedback-controlled, and the motor of the power steering device (not shown) is operated by the driver according to the steering force and the steering amount of the steering wheel.

Accordingly, the driving force applied to the power steering device is proportional to the steering force applied to the steering wheel by the driver, and the power assisting force assists the turning operation of the vehicle.

In this embodiment, the value of the torque signal Ts1 outputted from the gain / midpoint potential adjusting means 5a-2 when the substantial steering force acting on the steering wheel is "0" in the normal temperature state is medium. It is designed to match the point potential of 2.5 volts, and the power steering controller recognizes this 2.5 volt input as a substantial power assist command "0". That is, when the output Ts1 from the gain / midpoint potential adjusting means 5a-2 is 2.5 volts, which is the same as the midpoint potential, the power steering controller receiving the output Ts1 supplies the power to the power assist motor. The torque command value becomes “0” and power assist is stopped.

In the power assist of the right turn, the output Ts1 from the gain / midpoint potential adjusting means 5a-2 is 2.
When the voltage exceeds 5 volts, the power assist of the left turn is controlled by the output Ts from the gain / midpoint potential adjusting means 5a-2.
Activates when 1 drops below 2.5 volts.

However, strictly speaking, in order to prevent inadvertent hunting operation of the power steering device, a certain dead zone is set above and below the midpoint potential on the side of the power steering controller. In general, the power assist is not executed, ignoring the fluctuation of the torque signal Ts1 at the time.

The frequency characteristic of the signal input suitable for the power steering controller used in this embodiment is 50
The cut-off frequency characteristic of the low-pass filter 5a-1 of the torque signal output circuit 5A is set to 500 Hz in accordance with this characteristic. Therefore,
There is no frequency mismatch between the torque signal output circuit 5A and the power steering controller, and the power steering controller uses the torque signal output circuit 5A to control the steering force acting on the steering wheel, that is, the torque. The signal Ts1 can be accurately detected.

In this embodiment, the torque signal output circuit 5A
Although the cut-off frequency of the low-pass filter 5a-1 is set to 500 Hz, there are naturally power steering controllers having other frequency characteristics. Low-pass filter with appropriate cut-off frequency characteristics
By selecting the filter 5a-1, up to 50k
It is possible to deal with a power steering controller having a frequency characteristic up to Hz (the oscillation frequency of the oscillation circuit 10 itself).

As described above, on the downstream side of the torque detecting circuit 2, there is provided a rectifying circuit section 3A dedicatedly provided for a power steering controller which performs a very important function with respect to the controllability and safety of the vehicle. Since the comparison circuit 4A and the torque signal output circuit 5A are connected and operate only for the power steering controller, the reliability of the torque signal Ts1 transmitted to the power steering controller is sufficiently ensured and important. It is possible to accurately operate a power steering controller, which is a peripheral device.

On the other hand, on the downstream side of another rectification circuit section 3B provided in parallel with the rectification circuit section 3A, one comparison circuit 4 commonly used for a plurality of torque signal output circuits is provided.
B is provided, and a plurality of torque signal output circuits 5B, 5C, 5D are further connected in parallel downstream of the comparison circuit 4B.

The basic configuration of each of the torque signal output circuits 5B, 5C and 5D is substantially the same as that of the above-described torque signal output circuit 5A. However, the cut-off frequency characteristics of the low-pass filters 5b-1, 5c-1, and 5d-1 are different between the torque signal output circuits 5B, 5C, and 5D.

That is, the torque signal output circuit 5B is for outputting the backup torque signal Ts2 to the power steering controller, and the cut-off frequency characteristic of the low-pass filter 5b-1 is also In accordance with the power steering controller described above, the frequency is set to 500 Hz (the upper limit is 50 kHz) as described above.

The gain / middle-point potential adjusting means 5b-2 of the torque signal output circuit 5B is, like the gain / middle-point potential adjusting means 5a-2 described above, provided with the torque detecting section 9 of the torque detector 9 caused by a change in the environmental temperature. The value of the output gain is controlled by the microprocessor of the control unit 12 so that the characteristic change is absorbed and the appropriate torque signal Ts2 is output. At the same time, the voltage drift is absorbed and the midpoint potential becomes 2.5 volts. Thus, the midpoint potential is controlled by this microprocessor.

On the power steering controller side, the torque signal T from the torque signal output circuit 5A is usually used.
The drive control of the power steering device is performed based on s1, but a problem occurs in the rectifier circuit section 3A, the comparison circuit 4A, the torque signal output circuit 5A, etc., so that the torque signal Ts1 becomes abnormal, and the torque signal Ts2 becomes If normal, the torque signal Ts1 from the torque signal output circuit 5A
Is ignored, and the torque signal T from the torque signal output circuit 5B is ignored.
s2 is read as a power assist command, and the drive of the power steering device is controlled based on the torque signal Ts2.

That is, the voltage monitoring unit 13 provided in the above-described adjustment control circuit 6 includes the torque signals Ts1 and Ts2, the power supply voltage Vc, and the torque signals Ts3 and Ts described later.
4 is constantly monitored, and when it is determined that the torque signal Ts1 is out of the range of the normal value and the torque signal Ts2 is within the range of the normal value, the power steering controller is instructed. Thus, the command is issued to ignore the torque signal Ts1 and adopt the value of the torque signal Ts2.

Further, the torque signal output circuit 5C
This is for outputting a torque signal Ts3 to the navigation system, and its low-pass filter 5c-
The cut-off frequency characteristic of 1 is 1 kHz according to the characteristics of the car navigation system in the present embodiment.
z. Therefore, the torque signal output circuit 5C
There is no frequency mismatch between the vehicle and the car navigation system, and the car navigation system accurately detects the steering force acting on the steering wheel, that is, the torque signal Ts3 via the torque signal output circuit 5C. Can be detected. As above,
By selecting the cut-off frequency characteristic of the low-pass filter 5c-1, it is possible to deal with a car navigation system having a frequency characteristic up to 50 kHz.

The gain / midpoint potential adjusting means 5c-2 of the torque signal output circuit 5C absorbs a change in characteristics of the torque detector 9 caused by a change in environmental temperature, and adjusts the characteristic in proportion to the operating force of the steering wheel. The output gain value is controlled by the microprocessor of the control unit 12 so that the proper torque signal Ts3 is output, and at the same time, the microprocessor controls the midpoint so that the voltage drift is absorbed and the midpoint potential is maintained. The potential is controlled. gain·
The output gain and the midpoint potential set in the midpoint potential adjusting means 5c-2 are adapted to the characteristics of the car navigation system, and have different values from those for the power steering controller. The output gain and the value of the midpoint potential are adjusted according to the characteristics of the peripheral devices connected to the torque signal output circuits 5A, 5B, 5C, and 5D.
Can be arbitrarily set by the control unit 12.

That is, the non-volatile memory of the microprocessor provided in the control unit 12 includes the gain / midpoint potential adjusting means 5a-2 and 5b-2 of the torque signal output circuits 5A and 5B for the power steering controller. The common temperature correction data and the temperature correction data for the gain / midpoint potential adjusting means 5c-2 of the torque signal output circuit 5C for the car navigation system are stored together, and a temperature detecting means (not shown) The microprocessor reads the set values of the midpoint potential and the gain corresponding to the current environmental temperature from the respective temperature correction data according to the environmental temperature value detected by 5a-2, 5b-2 and the gain / midpoint potential adjusting means 5c-2 are set.

According to this embodiment, the steering force acting on the steering wheel can be directly input to the car navigation system via the torque signal output circuit 5C. Without having to wait, the car navigation system can immediately detect the driver's steering operation, and can recognize the steering operation and the like when the vehicle is stopped waiting for a traffic light. Therefore, at the stage before the car starts or changes course, it is also possible to display a warning indicating an error such as a right or left turn on the target route in advance.
The convenience of the navigation system is further improved.

The output from the torque signal output circuit 5C may be input to a car navigation system as data equivalent to a conventional turn signal. FIG. 2B is a conceptual diagram showing the output from the gain / midpoint potential adjusting means 5c-2 of the torque signal output circuit 5C in correspondence with the turning operation of the steering wheel. As shown in FIG. 2B, when the steering wheel is rotated left and right, the output voltage linearly increases or decreases in proportion to the steering torque with reference to the midpoint potential. Therefore, a predetermined dead zone above and below the midpoint potential,
For example, a dead zone of ± α volt is set, and as shown in FIG. 2 (a), when the output voltage increases outside the dead zone and increases, the right turn signal signal and the output voltage fall outside the dead zone. In the case of a decrease, the signal is output as a turn signal for turning left, so that the same turn signal as in the related art can be obtained.

The simplest construction method is a comparator (comparator) that outputs an ON signal at the midpoint potential + α volt or more inside the gain / midpoint potential adjusting means 5c-2 and at the midpoint potential−α volts or less. A comparator (comparator) for outputting an ON signal is provided, and the former is input to the car navigation system as a right turn signal and the latter as a left turn signal. Also, by incorporating the vehicle speed signal of the automobile into the torque signal output circuit 5C, it is possible to output information combining steering and vehicle speed, for example, steering operation information at a certain speed or higher.

Further, by monitoring the output abnormality from the torque signal output circuit 5C on the side of the car navigation system, a failure of the steering force detecting magnetostrictive torque sensor 1 is displayed as a warning on the car navigation system. It is also possible.

The torque signal output circuit 5D provides a torque signal T to meters on the instrument panel.
s4 is output, and the cut-off frequency characteristic of the low-pass filter 5d-1 is set to 100 Hz in accordance with the characteristics of meters in this embodiment. Therefore, there is no occurrence of a frequency matching failure between the torque signal output circuit 5D and the meters, and the meters on the instrument panel control the steering force acting on the steering wheel via the torque signal output circuit 5D. That is, the torque signal Ts4 can be accurately detected. As described above, by selecting the cut-off frequency characteristic of the low-pass filter 5d-1, a maximum of 50 kHz can be obtained.
It is possible to deal with meters having frequency characteristics up to z.

The gain / midpoint potential adjusting means 5d-2 of the torque signal output circuit 5D absorbs a change in characteristics of the torque detector 9 caused by a change in environmental temperature, and adjusts the characteristic in proportion to the operating force of the steering wheel. The output gain value is controlled by the microprocessor of the control unit 12 so that the proper torque signal Ts4 is output, and at the same time, the microprocessor controls the midpoint so that the voltage drift is absorbed and the midpoint potential is maintained. The potential is controlled. gain·
The output gain and the midpoint potential set in the midpoint potential adjusting means 5d-2 are adapted to the characteristics of the meters on the instrument panel, and are different from those for the power steering controller and the car navigation system. Have different values.

That is, the non-volatile memory of the microprocessor provided in the control unit 12 includes the gain / midpoint potential adjusting means 5a-2 and 5b-2 of the torque signal output circuits 5A and 5B for the power steering controller. Together with the common temperature correction data and the temperature correction data for the gain / midpoint potential adjusting means 5c-2 of the torque signal output circuit 5C for the car navigation system, the gain of the torque signal output circuit 5D for meters and the like. Temperature correction data for the midpoint potential adjusting means 5d-2 is also stored, and this microprocessor gains according to the value of the environmental temperature detected by the temperature detecting means (not shown).
The set values of the midpoint potential and the gain corresponding to the current environmental temperature are read from the temperature correction data for the midpoint potential adjusting means 5c-2, and the values are set in the gain / midpoint potential adjusting means 5d-2. .

Although these car navigation systems and meters have convenient functions for driving a car, they do not necessarily play important functions in terms of the maneuverability and safety of the car, and therefore, the present embodiment is not limited thereto. , A set of a rectifier circuit unit 3B and a comparison circuit 4B commonly used for these peripheral devices are provided downstream of the torque detection circuit 2, and a torque signal output circuit 5C for a car navigation system, and By connecting the torque signal output circuits 5D for meters and the like in parallel, the number of rectification circuit sections and comparison circuits required for the circuit configuration is limited to one set of the rectification circuit section 3B and the comparison circuit 4B. are doing. Further, a torque signal output circuit 5B for backup output to the power steering controller is provided with a torque signal output downstream of the comparison circuit 4B in order to cope with failure of the rectifier circuit section 3A, the comparison circuit 4A, and the torque signal output circuit 5A. They are connected in parallel with the circuits 5C and 5D.

Of course, if it is necessary to further connect another peripheral device having a different frequency characteristic,
Several other torque signal output circuits having low-pass filters having different cut-off frequency characteristics can be additionally provided.

Several rectifier circuits are provided in parallel with the rectifier circuits 3A and 3B on the downstream side of the torque detection circuit 2, and one important peripheral device is further provided downstream of the rectifier circuit. Or a torque signal output circuit for the important peripheral device, or a common comparison circuit common to a plurality of peripheral devices and a plurality of torque signal output circuits for the peripheral device in parallel. It is also possible to deploy.

[0049]

The magnetostrictive torque sensor for detecting steering force according to the present invention is configured such that a plurality of torque signal output circuits having low-pass filters having different frequency characteristics are connected in parallel on the downstream side of the comparison circuit. Therefore, a single oscillation excitation source and torque detection circuit can transmit a torque signal related to steering operation to various peripheral devices having different input frequency characteristics. Also, since only one pickup part (torque detection circuit) for actually detecting the steering force is required, the structure around the steering column does not become complicated, and even when a plurality of peripheral devices are mounted, the structure is not changed. And the increase in manufacturing cost are minimized.

In addition, a plurality of rectifier circuits are connected in parallel on the downstream side of the torque detection circuit, and at least one of the rectifier circuits is connected on the downstream side of only one of the important peripheral devices. While connecting the circuit and the torque signal output circuit, downstream of the other rectifier circuit section, one comparison circuit for a plurality of other peripheral devices of relatively low importance,
Since the torque signal output circuits of these other plural peripheral devices are connected in parallel, the operation of important peripheral devices is sufficiently guaranteed, while a large number of peripheral devices of relatively low importance are added. Even if such a case is required, the complexity of the circuit configuration and the increase in manufacturing cost can be minimized.

The midpoint potential and the gain of each torque signal output circuit can be adjusted by a single adjustment control circuit, which is economical.

[Brief description of the drawings]

FIG. 1 is a simplified block diagram showing a main part of a circuit configuration of a steering force detecting magnetostrictive torque sensor according to an embodiment to which the present invention is applied.

FIG. 2A is a conceptual diagram showing a signal output corresponding to a turn signal, and FIG. 2B is a conceptual diagram showing an output from a torque signal output circuit corresponding to a rotation operation of a steering wheel. .

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Magnetostrictive torque sensor for steering force detection 2 Torque detection circuit 3A, 3B Rectification circuit section 3a-1, 3a-2 A pair of rectification circuits 3b-1, 3b-2 A pair of rectification circuits 4A, 4B Comparison circuits 5A, 5B, 5C, 5D Torque signal output circuit 5a-1, 5b-1, 5c-1, 5d-1 Low-pass
Filter 5a-2, 5b-2, 5c-2, 5d-2 Gain / midpoint potential adjusting means 6 Adjustment control circuit 7a, 7b Detection coil 8a, 8b Excitation coil 9 Torque detection unit 10 Oscillation circuit (oscillation excitation source) 11 buffer (oscillation excitation source) 12 control unit 13 voltage monitoring unit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kenichi Higashi 300-Takatsuka-cho, Hamamatsu-shi, Shizuoka Suzuki Co., Ltd. F-term (reference) 3D033 CA03 5H004 GA34 GA35 GB12 HA10 HB01 HB10 JB15 JB16 JB17 KA45 MA12

Claims (4)

[Claims] A torque detection circuit including an oscillation excitation source, a pair of magnetic anisotropic members, an excitation coil, and a detection coil;
A rectification circuit unit including a pair of rectification circuits that rectify the electric signals output from each of the detection coils, a comparison circuit that calculates a deviation of the electric signals output from these rectification circuits and outputs the deviation as a torque detection signal, A low-pass filter that smoothes the torque detection signal output from the comparison circuit based on a predetermined frequency characteristic, and a gain that adjusts the midpoint potential of the output of the low-pass filter, multiplies by a predetermined gain, and outputs the multiplied to a peripheral device. A steering signal detecting magnetostrictive torque sensor comprising: a torque signal output circuit having a midpoint potential adjusting means; and a plurality of torque signals having low-pass filters having different frequency characteristics on the downstream side of the comparison circuit. A magnetostrictive torque sensor for detecting a steering force, wherein output circuits are connected in parallel. 2. A plurality of rectification circuit sections are connected in parallel on the downstream side of the torque detection circuit, and at least one of the rectification circuit sections is connected.
A single comparison circuit and a torque signal output circuit are connected downstream of one rectification circuit section, and one comparison circuit and low-pass filters having different frequency characteristics are provided downstream of the other rectification circuit sections. 2. The magnetostrictive torque sensor for detecting a steering force according to claim 1, wherein a plurality of torque signal output circuits provided are connected in parallel. 3. A magnetostrictive torque sensor for steering force detection according to claim 2, wherein a power steering controller as a peripheral device is connected downstream of said one torque signal output circuit. 4. A control circuit for setting a midpoint potential and a gain is provided in each of the gain / midpoint potential adjusting means of each of the torque signal output circuits. The steering force detecting magnetostrictive torque sensor according to claim 3.