JP2001324321A - Rotation angle detector, torque detector, and steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation angle detector capable of detecting a rotation angle even if a drooping portion exists in the characteristic of a detection signal from a detection means and facilitating the accuracy control of detection signals from the detection means when manufactured. SOLUTION: This rotation angle detector is equipped with bodies 12 of rotation, targets 15 provided on the bodies 12 so that their detected portions are continuously changed as the bodies 12 rotate, a first detection means 1A for detecting approaching portions of the targets 15, and a second detection means 1B for detecting approaching portions of the targets 15 so as to output a detection signal different in phase by a specified electrical angle from the detection signal outputted by the first detection means 1A. The angular displacement in the rotating direction of the bodies 12 is detected based on portions detected by the first and second detection means 1A, 1B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a technique for detecting a position of a rotating body continuously as the rotating body rotates.
A rotation angle detection device that detects an adjacent part of the target provided on the rotating body and detects a displacement angle of the rotating body in the rotation direction based on the detected part, and a connecting shaft that connects the input shaft and the output shaft. The present invention relates to a torque detection device that detects a torque applied to an input shaft based on a generated torsion angle, and a steering device that drives an electric motor based on a detection result of the torque detection device to generate a steering assist force.

[0002]

2. Description of the Related Art There is a steering apparatus for an automobile that drives an electric motor to assist the steering to reduce the burden on the driver. It comprises an input shaft connected to a steered wheel (steering wheel), an output shaft connected to a steered wheel by a pinion and a rack, and a connection shaft connecting the input shaft and the output shaft. A torque detection device detects a steering torque applied to an input shaft, and drives and controls an electric motor for steering assistance linked to an output shaft based on the steering torque detected by the torque detection device.

FIG. 36 shows that the applicant of the present invention
FIG. 1 is a principle diagram showing a configuration example of a main part of a torque sensor (torque detection device) proposed in the patent application No. 0665.
This torque detection device shows a case where it is used for a steering device, in which a steering wheel 1 is connected to an upper end portion,
A projection 22 made of a magnetic material is spirally formed along a peripheral surface of an intermediate portion of an upper shaft 21 (input shaft) of a steering shaft (steering shaft) having a torsion bar 25 connected to a lower end thereof.
(Projections) are provided. When the upper shaft 21 rotates, the MR sensor 1A (a magnetoresistive element, a magnetic sensor) is used to detect the position of the protrusion 22 made of a magnetic material that moves in the axial direction of the upper shaft 21. 21 is provided in parallel with an appropriate gap, and is fixed to a portion where the vehicle body does not move.

The lower shaft 23 (output shaft) of the steering shaft has an upper end connected to a torsion bar 25 and a lower end connected to a pinion 26. Like the upper shaft 21, a protrusion 24 (protrusion) made of a magnetic material is provided spirally along the peripheral surface of the intermediate portion of the lower shaft 23. Also,
When the lower shaft 23 rotates, an MR sensor 2A (magnetoresistive element, magnetic sensor) is used to detect the position of the protrusion 24 made of a magnetic material that moves in the axial direction of the lower shaft 23.
Is provided in parallel with the lower shaft 23 with an appropriate gap, and is fixed to a portion where the vehicle body does not move.

Each of the MR sensors 1A and 2A includes, for example, a voltage dividing circuit composed of two magnetic resistances and a bias magnet provided on a side not facing the steering shaft. The bias magnet enhances the magnetic field on the surface of the steering shaft in order to increase the change in the magnetic field due to the protrusions 22 and 24 made of a magnetic material and increase the sensitivity of the MR sensors 1A and 2A.

The output voltage of the MR sensor 1A is subtracted by a subtraction circuit 27.
And the output voltage of the MR sensor 2A is
And the amplifier 29. The output voltage of the amplifier 29 is output as a signal indicating the rotation angle (steering angle) of the steering shaft detected by the rotation angle detection device including the lower shaft 23, the protrusion 24 made of a magnetic material, and the MR sensor 2A. The output voltage of the subtraction circuit 27 is supplied to the amplifier 28, and the output voltage of the amplifier 28 is output as a signal indicating the steering torque applied to the steering wheel 1 detected by the torque detection device.

In the torque detecting device having such a configuration, as the upper shaft 21 and the lower shaft 23 rotate within the range of 0 ≦ θ <360 °, the magnetic field closest to the detection surfaces of the MR sensors 1A and 2A is obtained. The protrusions 22 and 24 made of material move in the axial direction of the upper shaft 21 and the lower shaft 23. The protrusions 22 and 24 made of a magnetic material include an upper shaft 21 and a lower shaft 23.
Are provided spirally along the peripheral surface of the MR sensor 1A and the axial position of the projections 22 and 24 made of a magnetic material closest to the detection surfaces of the MR sensors 1A and 2A. , And the rotation angles of the upper shaft 21 and the lower shaft 23 can be made to correspond to each other.

For example, the output voltages of the MR sensors 1A and 2A and the rotation angles (steering angles) of the upper shaft 21 and the lower shaft 23 are set so as to have the same linear relationship. When the lower shaft 23 is rotated a plurality of times, each output of the MR sensors 1A and 2A shows a voltage waveform of a 360 ° cycle, and the output voltages of the MR sensors 1A and 2A cause the outputs of the upper shaft 21 and the lower shaft 23, respectively. Each rotation angle can be detected.

If the steering torque is applied to the steering wheel 1 and the torsion bar 25 has a twist angle, the output voltages of the MR sensors 1A and 2A are
Since a voltage difference corresponding to the torsion angle is generated, the torsion angle is obtained by calculating the voltage difference by the subtraction circuit 27, and a signal indicating the steering torque can be output from the amplifier. Further, a signal indicating the rotation angle (steering angle) of the steering shaft, which is detected by the rotation angle detecting device including the lower shaft 23, the protrusion 24 made of a magnetic material, and the MR sensor 2A, can be output from the amplifier 29.

In the conventional electric power steering apparatus (steering apparatus), a torque detecting device for detecting the steering torque is required, and a steering shaft for connecting the steering wheel and the steering mechanism is connected to the steering wheel side. The input shaft and the output shaft on the steering mechanism side are connected via a small-diameter torsion bar, and the relative angular displacement generated at the connection portion between the two shafts with the torsion of the torsion bar due to the action of the steering torque. A torque detecting device configured to detect and calculate the steering torque (rotation torque) based on the detection result is used.

Many of the conventional torque detecting devices are configured to include a contact-sliding portion such as a potentiometer, and there is a problem in that the output changes over time due to wear of the sliding contact portion, resulting in poor durability. there were. In addition, a torque detection device configured to detect the relative angular displacement between the input shaft and the output shaft caused by the torsion of the torsion bar through the impedance change of the magnetic circuit formed at the connecting portion between the two shafts has been put into practical use. However, this device has a complicated structure,
There was a problem that the manufacturing cost was high.

In order to solve such a problem, the present applicant proposed in Japanese Patent Application No. 11-100665 or the like a torque detecting device having a simple configuration capable of detecting a rotating torque applied to a rotating shaft in a non-contact manner. ing. This apparatus is provided with a plurality of magnetic targets which are arranged side by side in the circumferential direction of a target rotating shaft, and each of which is tilted at substantially the same angle with respect to the axial direction, and which are disposed opposite to the outside of the target. A rotation angle detection device including a magnetic sensor (MR sensor) that emits an output that changes in accordance with the passage is provided with two sets of connecting portions for both the input shaft and the output shaft.

According to this configuration, the two sets of magnetic sensors are:
For each rotation of the input shaft or the output shaft, a voltage output that changes substantially linearly in a cycle corresponding to the circumferential length of the target facing each other is generated, so that the rotation angles of the input shaft and the output shaft are respectively set. The rotation torque (steering torque) applied to the input shaft by operating the steered wheels can be detected in a non-contact manner based on the output of the magnetic sensor corresponding to the input shaft and the output of the magnetic sensor corresponding to the input shaft and the output shaft. It can be calculated based on the difference between the rotation angles of the two axes given as the difference.

However, the targets arranged side by side on the outer periphery of the rotary shaft are in the form of partial spirals inclined at substantially equal angles with respect to the axial direction, and there are discontinuous portions corresponding to the number of units arranged in the circumferential direction. Exists. Therefore, there is a problem that a non-linear change region corresponding to the discontinuous portion appears in the outputs of the magnetic sensors arranged to face each other, and the detection of the rotation angle in this region becomes uncertain. Therefore, the input shaft and output shaft
Each of the two rotation angle detectors is provided with two magnetic sensors, each of which is shifted in phase in the circumferential direction of the corresponding target, and is selectively switched for use. The angle and the rotation torque can be detected.

FIG. 35 is an explanatory diagram showing an example of a change mode of the output voltages of the two magnetic sensors. The horizontal axis in the figure is
The rotation angle of the rotating shaft to be detected is shown. The solid line in the figure indicates the output voltage of one magnetic sensor, and the broken line indicates the output voltage of the other magnetic sensor. As shown, the output voltage of the magnetic sensor is 360 ° / N
(N is the number of juxtaposed targets) is defined as one cycle, and a region that changes linearly while each target passes and a region that changes non-linearly while a discontinuous portion between the targets passes is defined as a period. Fig. 7 shows a repeated change mode.

The mounting positions of the two magnetic sensors are as follows:
The output voltage is determined so as to have a deviation corresponding to an angle corresponding to substantially a half cycle of the output voltage. As a result, as shown in FIG. 35, the non-linear change region of the output voltage of one magnetic sensor is included in the linear change region of the output voltage of the other magnetic sensor. Therefore, by switching between the two magnetic sensors, it is possible to use only the linear region where an output linearly corresponding to the change in the rotation angle is obtained, and it is possible to detect the rotation angle and the rotation torque with high accuracy.

[0017]

In the torque detecting device described with reference to FIG. 36, the MR sensors 1A and 2A
The output voltage of each of the projections 22 and 24 made of the magnetic material at the break between the start and end of each of the protrusions is shown in FIG.
As shown in FIG. 7 (a), there is a problem that the characteristics are broken and become non-linear, and there is a portion that cannot be used for rotation angle detection and torque detection. Therefore, conventionally, a method is known in which a plurality of MR sensors are used and a phase shift is given to each output voltage as shown in FIG. ing.

For example, as shown in FIG. 37 (c), the output voltages of the two MR sensors are shifted by 180 ° in phase, and one output voltage is inverted to compare the two output voltages. Then, there is a method of detecting the absolute angle. However, it is difficult to control the accuracy of the intersection of the output voltages of the two MR sensors.
When the output voltage of the sensor is handled with 10-bit accuracy, the accuracy of the output voltage at the intersection is required to be 0.1% or more, and there is a problem that it is difficult to control the accuracy of the output voltage of the MR sensor during manufacturing. In addition, when the torque detecting device as described above is used for a steering device of a vehicle, if the torque detecting device breaks down (a disconnection of a signal line or the like), there is a possibility that reverse assist may occur, and it is necessary to immediately stop the torque detection. However, there is also a problem in that the torque detection is immediately stopped and the assist torque is suddenly reduced to zero.

Also, as described above, the circumferential direction of the target is 2 mm.
In a torque detector with two magnetic sensors,
Based on the output voltage obtained as shown in FIG. 35, it is necessary to select which magnetic sensor output is used for calculating the rotational torque. Conventionally, in this selection, as shown in FIG. 35, upper and lower threshold voltages V _S1 and V _S2 are set in advance, and the output voltage of the magnetic sensor in use is set to the threshold voltage V _S
When exceeded _S1, or when it falls below the threshold voltage V _S2, is carried out by the procedure for switching to the other of the magnetic sensor.

However, it is known that the output characteristics of an MR sensor used as a magnetic sensor are not invariable, and in particular, vary greatly due to the influence of the ambient temperature. . FIG.
FIG. 4 is an explanatory view of a problem of a conventional selection procedure, schematically showing a change state of an output voltage of one magnetic sensor.

The change in output characteristics due to the influence of the ambient temperature is as follows.
It appears as an increase or decrease in the rate of change (slope) of the output voltage in the linear change region. FIG. 38 (a) shows a state where the rate of change has increased, and FIG. 38 (b) shows a state where the rate of change has decreased.

Upper and lower threshold voltages V used for conventional selection
_S1And V_S2Are set for standard output characteristics.
In the state shown in FIG.
Pressure V _S1And V_S2When using, use hatching in the figure.
As shown in the figure, both ends of the linear change area are cut wide.
Will be discarded and switch to the other magnetic sensor
During the time when the output of the magnetic sensor is in the nonlinear change region.
And the accuracy of the rotational torque calculated immediately after switching is low.
There is a problem of going down. In addition, in the state of FIG.
As shown in the figure, the maximum value and the maximum
The small value is the threshold voltage V_S1And V_S2Not reach the other
There is even a risk that switching to the magnetic sensor will not take place.

Such a problem is alleviated by increasing or decreasing the threshold voltage for selection switching according to the ambient temperature. For this purpose, it is necessary to measure the temperature around the magnetic sensor, and the structure of the control system is changed. In addition, the change in the output characteristics of the magnetic sensor is not caused only by the influence of the ambient temperature, and the output characteristics are different for each of the plurality of magnetic sensors. The selection of the emitting magnetic sensor is not always ensured.

The present invention has been made in view of the above circumstances, and in the first to seventh inventions, even if there is any part in the characteristics of the detection signal of the detection means, the rotation angle can be detected. It is an object of the present invention to provide a rotation angle detection device that can easily control the accuracy of a detection signal of a detection unit during manufacturing. According to the eighth to eleventh and thirteenth inventions, there is provided a torque detecting device capable of detecting torque even if there is a portion in the characteristic of the detection signal of the detection means and easily controlling the accuracy of the detection signal of the detection means at the time of manufacturing. The purpose is to provide.

A twelfth aspect of the present invention aims to provide a torque detecting device that does not stop torque detection even when a failure occurs.

According to the fourteenth to sixteenth aspects, the magnetic sensor emitting an effective output can be reliably selected from the two magnetic sensors arranged in parallel in the circumferential direction of the target. It is an object of the present invention to provide a torque detection device capable of calculating a rotation torque using an output with high accuracy. According to the seventeenth aspect, even if there is any part in the characteristic of the detection signal of the detection means of the torque detection device, the torque can be detected, and the accuracy control of the detection signal of the detection means at the time of manufacturing the torque detection device is easy. It is an object to provide a steering device. It is a further object of the eighteenth invention to provide a steering apparatus for an automobile which can use the torque detecting apparatus for detecting a steering torque and can perform various controls based on the detected torque with high accuracy.

[0027]

According to a first aspect of the present invention, there is provided a rotation angle detecting device, comprising: a rotating body;
The target provided on the rotating body, the first detection means for detecting a part close to the target, and the phase of the detection signal output by the first detection means are set so that the detected part changes continuously. Second detection means for detecting a portion in proximity to the target so as to output a detection signal having a different electrical angle, wherein the rotating body is detected based on the portions detected by the first detection means and the second detection means, respectively. Is characterized by detecting a displacement angle in the rotation direction of the camera.

In this rotation angle detecting device, the target is provided on the rotating body so that the detected part continuously changes as the rotating body rotates, and the first detecting means is provided on the part near the target. Is detected. The second detection means detects a portion close to the target so as to output a detection signal having a phase different from the detection signal output by the first detection means by a predetermined electrical angle, and the first detection means and the second detection means The displacement angle of the rotating body in the rotation direction is detected based on the detected portions. This makes it possible to realize a rotation angle detection device that can detect the rotation angle even if there is a portion in the characteristic of the detection signal of the detection means and can easily control the accuracy of the detection signal of the detection means during manufacturing. I can do it.

According to a second aspect of the present invention, in the rotation angle detecting device, the target includes a first inclined portion provided in one direction along the peripheral surface of the rotating body, and a target along the peripheral surface of the rotating body. And a second inclined portion provided to be inclined in the other direction.

In this rotation angle detecting device, the first inclined portion of the target is provided to be inclined in one direction along the peripheral surface of the rotating body, and the second inclined portion of the target is provided on the peripheral surface of the rotating body. Along the other direction, the rotation angle can be detected even if there is little variation in the characteristics of the detection signal of the detection means. In addition, it is possible to realize a rotation angle detection device that can easily control the accuracy of the detection signal of the detection unit at the time of manufacturing.

According to a third aspect of the present invention, in the rotation angle detecting device, the first inclined portion and the second inclined portion are substantially line-symmetric with respect to a straight line in the axial direction of the rotating body passing through a connection point between the two inclined portions. Characterized by having a relationship.

In this rotation angle detecting device, the first inclined portion and the second inclined portion have a substantially line-symmetric relationship with respect to a straight line in the axial direction of the rotating body that passes through the connection point between the two inclined portions.
The characteristics of the detection signal of the detection means have few parts,
Even if there is any part, the rotation angle can be detected, and a rotation angle detection device that can easily control the accuracy of the detection signal of the detection means at the time of manufacturing can be realized.

A rotation angle detecting device according to a fourth aspect of the present invention is characterized in that a plurality of the targets are provided continuously along the peripheral surface of the rotating body.

In this rotation angle detection device, since a plurality of targets are provided continuously along the peripheral surface of the rotating body, the detection sensitivity of the detection means is good, and the characteristics of the detection signal of the detection means are different from each other. , The rotation angle can be detected, and a rotation angle detection device that can easily control the accuracy of the detection signal of the detection means at the time of manufacturing can be realized.

According to a fifth aspect of the present invention, in the rotation angle detecting device, the target is magnetically discontinuous with respect to a peripheral portion, and the first detecting means and the second detecting means are magnetic sensors. .

In this rotation angle detecting device, the target is magnetically discontinuous with respect to the peripheral portion, and the first detecting means and the second detecting means are magnetic sensors. Even if there is a portion, the rotation angle can be detected, and a rotation angle detection device that can easily control the accuracy of the detection signal of the detection means at the time of manufacturing can be realized.

According to a sixth aspect of the present invention, in the rotation angle detecting device, the magnitude of the detection signal output by the first detecting means and the second detecting means at the time of the previous sampling, respectively, and the first detecting means and the second detecting means perform the current sampling. Determination means for determining the magnitude of the detection signal output at each time; and a substantially intermediate value between a maximum value and a minimum value to be taken by the detection signal and the first value.
Determining means for determining the magnitude of the detection signal output at the time of sampling by the detecting means or the second detecting means;
Determining means for determining whether the detection signals output by the detecting means and the second detecting means at the time of the current sampling are within a predetermined range, respectively, based on each determination result of each of the determining means, The present invention is characterized in that a displacement angle in a rotation direction is detected.

In this rotation angle detection device, the determination means
The magnitudes of the detection signals output by the first detection means and the second detection means at the time of the previous sampling, and the magnitudes of the detection signals output by the first detection means and the second detection means at the time of the current sampling, respectively, are determined. The means determines a magnitude of a substantially intermediate value between the maximum value and the minimum value to be taken by the detection signal and the detection signal output at the time of the current sampling by the first detection means or the second detection means. Still another determination means determines whether the detection signals output by the first detection means and the second detection means at the time of the current sampling are within a predetermined range, and based on each determination result of each determination means, The angle of displacement in the direction of rotation of is detected. This makes it possible to realize a rotation angle detection device that can detect the rotation angle even if there is a portion in the characteristic of the detection signal of the detection means and can easily control the accuracy of the detection signal of the detection means during manufacturing. I can do it.

According to a seventh aspect of the present invention, there is provided a rotation angle detecting device, wherein any one of the first detecting means and the second detecting means and the detecting means to be detected by the detecting means are based on each judgment result of each of the judging means. The apparatus further comprises a selecting means for selecting any one of the first inclined part and the second inclined part, and the detecting means and the inclined part selected at the previous sampling by the selecting means, and the detecting means at the last sampling and the current It is characterized in that a displacement angle of the rotating body in the rotation direction is detected based on the detection signals output at the time of sampling.

In this rotation angle detecting device, the selecting means includes:
Based on each determination result of each determination means, any one of the first detection means and the second detection means and any one of the first and second slope parts to be detected by the detection means Then, the displacement angle in the rotation direction of the rotating body is detected based on the detection means and the inclined portion selected by the selection means at the time of the previous sampling, and the detection signals output by the detection means at the time of the previous sampling and the current sampling, respectively. This makes it possible to realize a rotation angle detection device that can detect the rotation angle even if there is a portion in the characteristic of the detection signal of the detection means and can easily control the accuracy of the detection signal of the detection means during manufacturing. I can do it.

According to an eighth aspect of the present invention, there is provided a torque detection device according to any one of claims 1 to 7, wherein the rotation angle detection device is provided on each of an input shaft and an output shaft connected by a connection shaft.
A torque applied to the input shaft is detected based on a difference between a detection signal output by the first detection unit and a detection signal output by the second detection unit included in the rotation angle detection device due to a twist generated in the connection shaft. It is characterized by.

In this torque detecting device, the rotation angle detecting device according to any one of claims 1 to 7 is provided on each of the input shaft and the output shaft connected by the connecting shaft, and the rotation angle detecting device is provided with the rotation angle detecting device. The torque applied to the input shaft is detected based on the difference between the detection signal output by the first detection unit and the detection signal output by the second detection unit due to the twist generated in the connection shaft. Thus, even if there is any part in the characteristics of the detection signal of the detection means, torque detection is possible, and a torque detection device that can easily control the accuracy of the detection signal of the detection means at the time of manufacturing can be realized.

According to a ninth aspect of the present invention, there is provided a torque detecting device, wherein a sign of the difference between the detection signals output from the first detecting means and a sign of the difference between the detecting signals output from the second detecting means are determined. Means, and first comparing means for comparing the magnitudes of detection signals output by the first detection means and the second detection means on the input shaft side when the sign determination means determines the same sign of each difference. Further comprising:
It is characterized in that a torque applied to the input shaft is detected based on a comparison result of the comparison means.

In this torque detecting device, the sign judging means judges the sign of the difference between the detection signals output from the first detecting means and the sign of the difference between the detecting signals output from the second detecting means. When the first comparing means determines that the sign of each difference is the same, the first comparing means on the input shaft side.
The magnitudes of the detection signals output by the detection means and the second detection means are compared, and the torque applied to the input shaft is detected based on the comparison result of the first comparison means. Thus, even if there is any part in the characteristics of the detection signal of the detection means, torque detection is possible, and a torque detection device that can easily control the accuracy of the detection signal of the detection means at the time of manufacturing can be realized.

In the torque detecting device according to the tenth aspect, when the sign judging means judges that the sign of each difference is different, the intermediate value between the maximum value and the minimum value to be taken by each detection signal and the input signal Further provided is a second comparing means for comparing the magnitudes of the detection signals outputted by the first detecting means and the second detecting means on the shaft side, and based on the comparison result of the second comparing means,
It is characterized in that the torque applied to the input shaft is detected.

In this torque detecting device, when the sign judging means judges that the sign of each difference is different, the second comparing means makes the input shaft substantially intermediate between the maximum value and the minimum value which each detection signal should take. The magnitudes of the detection signals output by the first and second detection units are compared with each other, and the torque applied to the input shaft is detected based on the comparison result of the second comparison unit.
Thus, even if there is any part in the characteristics of the detection signal of the detection means, torque detection is possible, and a torque detection device that can easily control the accuracy of the detection signal of the detection means at the time of manufacturing can be realized.

According to an eleventh aspect of the present invention, there is provided the torque detecting device, wherein the first detecting means determines whether at least one of the detection signals output by the first detecting means is outside a predetermined range, and the second detecting means. To determine whether or not at least one of the detection signals respectively output is outside a predetermined range.
Determining means; and third comparing means for comparing the absolute value of the difference between the detection signals output by the first detection means and the absolute value of the difference between the detection signals output by the second detection means. And detecting a torque applied to the input shaft based on a comparison result of the second comparison unit, a determination result of the first determination unit, a determination result of the second determination unit, and a comparison result of the third comparison unit. It is characterized by being done.

In this torque detecting device, the first judging means judges whether at least one of the detection signals respectively output by the first detecting means is outside a predetermined range, and the second judging means judges whether the second detecting means has the second detecting signal. It is determined whether at least one of the detection signals respectively output by the means is outside a predetermined range. The third comparing means compares the absolute value of the difference between the detection signals output by the first detecting means and the absolute value of the difference between the detection signals output by the second detecting means. The torque applied to the input shaft is detected based on the result, the determination result of the first determination unit, the determination result of the second determination unit, and the comparison result of the third comparison unit. Thus, even if there is any part in the characteristics of the detection signal of the detection means, torque detection is possible, and a torque detection device that can easily control the accuracy of the detection signal of the detection means at the time of manufacturing can be realized.

According to a twelfth aspect of the present invention, there is provided a torque detecting device for detecting an abnormality of the detection signal output from the pair of the first detecting means and the pair of the second detecting means. Means for setting the difference between the detection signals output by each of the pair of detection means including detection means for outputting an abnormal detection signal when one of the detection signals is detected, When the number of signals is one, the torque applied to the input shaft is detected without using the detection signal.

In this torque detecting device, the abnormality detecting means detects the abnormality of the detection signal output by each of the first detecting means pair and the second detecting means pair, and the means for setting the difference to 0 is the abnormality detecting means. When one of the detection signals detects an abnormality, the difference between the detection signals output by each pair of detection units including the detection unit that outputs the abnormal detection signal is set to 0. When there is one abnormal detection signal, the torque applied to the input shaft is detected without using the abnormal detection signal. Thereby, even in the event of a failure, if there is only one failed detecting means and the remaining detecting means can detect torque,
A torque detection device that does not stop torque detection can be realized.

According to a thirteenth aspect of the present invention, there is provided the torque detecting device, wherein each of the detection signals output in accordance with the parts respectively detected by the first detecting means and the second detecting means, and the first detecting means and the second detecting means, Storage means for storing detection signals to be output in accordance with the parts respectively detected by the detection means, and detection signals output by the first detection means and the second detection means, and the storage means Means for outputting each of the detection signals to be output based on the contents stored by the first and second detection means for detecting each of the detection signals output by the means. , Which is characterized in that each detection signal indicates

In this torque detection device, each storage means
Each detection signal output in accordance with the part respectively detected by the first detection means and the second detection means,
Each detection signal to be output is stored in association with each part detected by the detecting means and the second detecting means.
The output unit outputs each detection signal to be output based on the detection signals output by the first detection unit and the second detection unit and the content stored in each storage unit, and the output unit outputs the detection signal. Each detection signal is a detection signal indicating a part detected by each of the first detection unit and the second detection unit. Thus, even if there is any part in the characteristics of the detection signal of the detection means, torque detection is possible, and a torque detection device that can easily control the accuracy of the detection signal of the detection means at the time of manufacturing can be realized.

A torque detector according to a fourteenth aspect of the present invention includes a plurality of magnetic targets which are arranged side by side in the circumferential direction of the rotating shaft, each of which is made of a magnetic material which is inclined at substantially equal angles with respect to the axial direction. Two magnetic sensors, which are arranged to face each other with their phases shifted in the direction and emit outputs that change according to the passage of each target, are separated from each other in the axial direction of the rotation shaft, and are provided in each set. A torque detecting device configured to calculate a rotational torque applied to the rotating shaft using an output difference of one of the selected magnetic sensors, wherein an absolute value of an output difference of a selected magnetic sensor and a non-selected magnetic sensor are determined. Comparing means for comparing the absolute value of the output difference between the sensors; determining means for determining whether the output difference of the selected magnetic sensor and the output difference of the non-selected magnetic sensor are positive or negative; With the comparison result of the comparison means Zui and characterized in that it comprises a selection means for selecting the magnetic sensor used for calculating the rotation torque.

According to the present invention, there is provided a torque detecting device comprising two sets of a target and a magnetic sensor in the axial direction of a target rotary shaft, and calculating a rotational torque based on an output difference between the two sets of magnetic sensors. When observing the output change of the selected magnetic sensor used for calculating the rotation torque in both sets, paying attention to the fact that the sign of this output difference is reversed between the linear change area and the non-linear change area, The transition from the linear change region to the non-linear change region is determined based on the positive / negative reverse rotation and the decrease in the absolute value of the output difference before the reverse rotation, and the magnetic sensor used for calculating the rotational torque is selected according to the result.

A torque detecting device according to a fifteenth aspect of the present invention has a first
(4) Under the condition that the result of the judgment by the judging means is the same for the selected magnetic sensor and the non-selected magnetic sensor, the selecting means in the four inventions, When the absolute value of the output difference of the magnetic sensor is smaller than the absolute value of the output difference of the non-selected magnetic sensor by more than a predetermined amount, the selection of the magnetic sensor is changed.

In the present invention, the absolute value of the output difference of the selected magnetic sensor, that is, the magnetic sensor used for calculating the current rotational torque is determined by the non-selected magnetic sensor, that is, the current rotational torque. When the state becomes smaller than the absolute value of the output difference of the magnetic sensor not used for the calculation, it is determined that the output of the magnetic sensor being selected is shifting from the linear change area to the non-linear change area, and is currently selected. A magnetic sensor that is not selected from the existing magnetic sensors is switched. However, when the output difference between the non-selected magnetic sensors is in the non-linear change region, the magnitude relationship between the absolute values as described above may be established. Positive and negative are checked together, and the switching is performed on condition that both of the positive and negative are the same.

A torque detecting device according to a sixteenth aspect of the present invention has a first
The rotating shaft according to the fourth or fifteenth invention is a connecting member of a first shaft and a second shaft coaxially connected via a torsion bar, and the target is a connecting portion of the first shaft and the second shaft. It is characterized by being provided near each.

According to the present invention, targets are arranged side by side on a first axis and a second axis which are coaxially connected via a torsion bar, and two magnetic sensors are arranged to face each other outside these targets. The difference between the large rotation angles generated between the two shafts due to the torsion of the torsion bar is accurately determined by the above-described selection of the magnetic sensor, and the rotational torque applied to the first and second shafts is obtained by using the result. Is detected with high accuracy.

According to a seventeenth aspect of the present invention, there is provided a steering device comprising: an input shaft connected to a steered wheel; an electric motor for steering assistance driven and controlled based on a steering torque applied to the steered wheel; and an output shaft interlocked with the electric motor. And a torque detection device according to any one of claims 8 to 13, which detects a steering torque applied to the input shaft by a torsion angle generated in a connection shaft connecting the input shaft and the output shaft. And

In this steering system, the input shaft is connected to the steered wheels, and the electric motor for assisting steering is driven and controlled based on the steering torque applied to the steered wheels. An output shaft is interlocked with the electric motor, and the torque detecting device according to any one of claims 8 to 13 detects a steering torque applied to the input shaft by a torsion angle generated in a connecting shaft connecting the input shaft and the output shaft. I do. As a result, even if there is a portion in the output voltage characteristic of the magnetic sensor of the torque detecting device, the torque can be detected, and the accuracy of the output voltage of the magnetic sensor at the time of manufacturing the torque detecting device can be easily controlled. The device can be realized.

A steering device according to an eighteenth aspect of the present invention includes the torque detecting device according to any one of claims 14 to 16, wherein a steering shaft that connects a steered wheel and a steering mechanism is used as the rotation shaft. It is characterized by the following.

In the present invention, the torque detecting device according to any one of claims 14 to 16 capable of calculating a torque with high accuracy is applied to a steering device of an automobile, and is applied to a steering shaft for steering. An accurate detection value of the steering torque is obtained, and this result is used for various controls such as drive control of a steering assist motor.

[0063]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing an embodiment. Embodiment 1 FIG. FIG. 1 is a schematic diagram schematically illustrating a configuration of a first embodiment of a rotation angle detection device and a torque detection device according to the present invention. The rotation angle detection device and the torque detection device are applied to a steering device of an automobile, and an input shaft 16 having an upper end connected to a steering wheel 1 (steering wheel).
And an output shaft 17 whose lower end is connected to a pinion 18 of a steering mechanism, coaxially connected via a small-diameter torsion bar 19 (connection shaft), and connects the steering wheel 1 and the steering mechanism. A steering shaft 13 is configured, and the vicinity of a connection portion between the input shaft 16 and the output shaft 17 is configured as follows.

A disk-shaped target plate 12 (rotary body) is coaxially fixed to the input shaft 16 near the end on the connection side with the output shaft 17. , A plurality (five in the figure) of targets 15 are juxtaposed. The target 15 is the target plate 12
As shown in a developed view of FIG. 2 in which the outer peripheral surface of the target plate 12 is developed, a first inclined portion 15a is provided to be inclined in one direction along the outer peripheral surface of the target plate 12, and is provided to be inclined in the other direction. The protrusions are made of a magnetic material and have a second inclined portion 15b. The protrusions are arranged at regular intervals in the circumferential direction of the outer peripheral surface of the target plate 12. The first inclined portion 15a and the second inclined portion 15b are substantially line-symmetric with respect to a straight line in the axial direction of the rotation axis of the target plate 12 that passes through the connection point.

A target plate 12 having a target 15 similar to that described above is also externally fixed near the end of the output shaft 17 on the connection side with the input shaft 16, and the target plate 12 on the output shaft 17 side is fixed. And the targets 15 of the target plate 12 on the input shaft 16 side are aligned side by side in the circumferential direction.

The sensor boxes 11 are arranged outside the target plates 12 so as to face the outer edges of the targets 15 on the respective outer circumferences. The sensor box 11 is fixedly supported on a stationary part such as a housing that supports the input shaft 16 and the output shaft 17. Inside the sensor box 11, MR sensors 1A and 1B (first detection means and second detection means) facing different portions in the circumferential direction of the target 15 on the input shaft 16 side, and the target 15 on the output shaft 17 side.
Sensors 2A and 2B facing different portions in the circumferential direction of
(The first detecting means and the second detecting means) are housed in such a manner that their circumferential positions are correctly aligned.

Each of the MR sensors 1A, 2A, 1B, 2B uses an element such as a magnetoresistive effect element (MR element) whose electric characteristics (resistance) change due to the action of a magnetic field. The sensor is configured to change the detection signal in accordance with the part to be processed, and these detection signals are given to a signal processing unit 14 using a microprocessor outside or inside the sensor box 11.

Hereinafter, the operation of the rotation angle detecting device and the torque detecting device having such a configuration will be described. MR sensor 1
As described above, the target 15 to which A, 2A, 1B, and 2B face each other is inclined in one direction along each outer peripheral surface of each target plate 12 coaxially fitted to the input shaft 16 and the output shaft 17. This is a magnetic ridge provided with the first inclined portion 15a and the second inclined portion 15b inclined in the other direction.

Therefore, when the input shaft 16 (output shaft 17) rotates around the axis, each of the MR sensors 1A, 1B (2A, 2A)
6B, while the corresponding targets 15 pass the positions facing each other, as shown in FIG. 6, as the rotation angle of the input shaft 16 (output shaft 17) changes, it rises and falls proportionally. A detection signal (indicated by A and B) is output.

The detection signals of the MR sensors 1A and 1B correspond to the rotation angle of the input shaft 16 on which the corresponding targets 15 are provided, and the MR sensors 2A and 2B
These detection signals correspond to the rotation angle of the output shaft 17 provided with the target 15 facing them. Therefore, the signal processing unit 14 can calculate the rotation angle of the input shaft 16 from the detection signals of the MR sensors 1A and 1B,
The signal processing unit 14 and the MR sensors 1A and 1B
It operates as a rotation angle detection device. The signal processing unit 14 outputs the output shaft 1 from the detection signals of the MR sensors 2A and 2B.
7, the signal processing unit 14 and the MR sensors 2A and 2B operate as a rotation angle detection device for the output shaft 17.

When a rotational torque is applied to the input shaft 16,
Each detection signal of the MR sensor 1A, 1B and the MR sensor 2A,
There is a difference between each detection signal of 2B. MR sensor 1A,
The 2A and the MR sensors 1B and 2B have a phase difference of, for example, 90 electrical degrees in the circumferential direction of the target plate 12. Therefore, since the respective detection signals can be mutually interpolated in the non-linear region, the phase angle may be any electrical angle of 1 ° to less than 360 ° as long as interpolation is possible.

Here, the detection signal of the MR sensor 1A and the MR
The difference between the detection signal of the sensor 2A or the difference between the detection signal of the MR sensor 1B and the detection signal of the MR sensor 2B is determined by the input shaft 1
This corresponds to the difference (relative angular displacement) in the rotation angle between the output shaft 6 and the output shaft 17. This relative angular displacement causes the input shaft 16 and the output shaft 1 to move under the action of the rotational torque applied to the input shaft 16.
7 corresponds to a torsion angle generated in the torsion bar 19 connecting the torsion bar 7 to the torsion bar 19. Therefore, the rotational torque applied to the input shaft 16 can be calculated based on the difference between the detection signals described above.

The operation of the rotation angle detection device and the torque detection device at the time of rotation angle detection (steering angle calculation) will be described below with reference to the flowcharts of FIGS. However, the MR sensors 1A and 2A and the MR sensors 1B and 2
The phase shift with respect to B is 90 electrical degrees. First, the signal processing unit 14 of the rotation angle detecting device determines that the detection signal A of the MR sensor 1A at the time of the previous sampling is larger than the detection signal B of the MR sensor 1B at the time of the previous sampling, and the detection signal A at the time of the current sampling is equal to or smaller than the detection signal B. It is determined whether or not there is (S
1).

In view of the sampling period and the steering speed (displacement speed of the steering angle), the change in the detection signals A and B from the region d to the region e or the change from the region a to the region h in FIG. This is a step for detection. However, in FIG. 6, the right rotation direction of the steered wheel 1 is set to the positive direction, and the detection signals A and B are linear from the predetermined lower limit threshold to the upper limit threshold (the connection between the first inclined portion 15a and the second inclined portion 15b). (The detection signal in the vicinity of the part becomes non-linear).

The signal processing section 14 determines that the detection signal A at the previous sampling is larger than the detection signal B and the detection signal A at the current sampling is equal to or smaller than the detection signal B (in FIG. 6,
(Indicates that the detection signals A and B are in the area e or the area h.)
If (S1), it is determined whether or not the detection signal A or the detection signal B at the time of the current sampling is larger than an intermediate value (middle point) of the possible values of the detection signals A and B as shown in FIG. (S5). Thus, it is determined whether the detection signals A and B are in the region e or the region h in FIG.

The signal processing section 14 determines that the detection signal A or the detection signal B at the time of the current sampling is larger than the middle point (in FIG. 6, the detection signals A and B are in the area e, and the detection signal A is lower than the upper threshold). (Indicating that there is) (S5), the selected sensor at the time of the current sampling is the MR sensor 1A, and the detection signal A as shown in FIG.
The part is output as "A-" (S6).

If the detection signal A or the detection signal B at the time of the current sampling is not larger than the middle point (in FIG. 6, the detection signals A and B are in the area h and the detection signal B is (S5), the selected sensor at the time of sampling this time is the MR sensor 1B,
Among the detection signals B as shown in FIG. 6, the lower right (monotonically decreasing) portion is set to "B-" during output (S11).

If the detection signal A at the previous sampling is not larger than the detection signal B or the detection signal A at the current sampling is not smaller than the detection signal B (S1), the signal processing unit 14 It is determined whether the signal A is smaller than the detection signal B and the detection signal A at the time of the current sampling is equal to or larger than the detection signal B (S2). This is the sampling period and steering speed (displacement speed of the steering angle)
In FIG. 6, this is a step for detecting a change in the detection signals A and B from the region e to the region d or a change from the region h to the region a.

The signal processing unit 14 determines that the detection signal A at the previous sampling is smaller than the detection signal B and the detection signal A at the current sampling is equal to or larger than the detection signal B (in FIG. 6,
It indicates that the detection signals A and B are in the area d or the area a)
If (S2), it is determined whether the detection signal A or the detection signal B at the time of the current sampling is larger than the middle point (S2).
7). Thereby, the detection signals A and B are
It is determined which of the area d and the area a is located.

The signal processing unit 14 determines that the detection signal A or the detection signal B at the time of the current sampling is larger than the middle point (in FIG. 6, the detection signals A and B are in the area d, and the detection signal B is lower than the upper threshold). (Indicating that there is) (S7), the selected sensor at the time of the current sampling is the MR sensor 1B, and the detection signal B as shown in FIG.
The part is set to "B +" during output (S8).

If the detection signal A or the detection signal B at the time of the current sampling is not larger than the middle point (in FIG. 6, the detection signals A and B are in the area a and the detection signal A is (Indicating that this is the case)
7), the selected sensor at the time of sampling this time is MR sensor 1
A, and a part of the detection signal A as shown in FIG. 6 which rises to the right (monotonically increases) is set to "A +" during output (S12).

If the detection signal A at the previous sampling is not smaller than the detection signal B or the detection signal A at the current sampling is not equal to or greater than the detection signal B (S2), the signal processing section 14 detects the current sampling. It is determined whether the signal A is larger than the upper threshold and the detection signal B at the time of the current sampling is larger than the lower threshold (S3). this is,
FIG. 6 is a step for determining whether or not the detection signals A and B are in the area c.

If the detection signal A at the time of the current sampling is larger than the upper threshold and the detection signal B at the time of the current sampling is larger than the lower threshold (in FIG. 6, the detection signals A and B fall within the region c). Yes, indicating that the detection signal B is greater than or equal to the lower limit threshold) (S3), the MR sensor 1B is used as the selected sensor at the time of the current sampling, and the detection signal B as shown in FIG. Is set to "B +" during output (S9).

If the detection signal A at the time of the current sampling is not larger than the upper threshold value or the detection signal B at the time of the current sampling is not larger than the lower threshold value (S3), the signal processing unit 14 sets the detection signal B at the current sampling time to It is determined whether or not the detection signal A at the time of the current sampling is larger than the upper limit threshold and larger than the lower limit threshold (S4). this is,
In FIG. 6, this is a step for determining whether or not the detection signals A and B are in the area f.

The signal processing section 14 determines that the detection signal B at the time of the current sampling is larger than the upper limit threshold and the detection signal A at the time of the current sampling is larger than the lower limit threshold (in FIG. 6, the detection signals A and B are in the area f. , Indicating that the detection signal A is greater than or equal to the lower threshold) (S4), the selected sensor at the time of the current sampling is the MR sensor 1A, and the detection signal A as shown in FIG. The part is output as "A-" (S10).

If the detection signal B at the time of the current sampling is not larger than the upper threshold value or the detection signal A at the time of the current sampling is not larger than the lower threshold value (S4), the signal processing unit 14 sets the detection signal A at the current sampling time to It is determined whether or not the detection signal B at the time of the current sampling is smaller than the lower threshold and smaller than the upper threshold (S13). This is a step for determining whether or not the detection signals A and B are in the area g in FIG.

The signal processing unit 14 determines that the detection signal A at the time of the current sampling is smaller than the lower limit threshold and the detection signal B at the time of the current sampling is smaller than the upper limit threshold (in FIG. 6, the detection signals A and B are in the region g). , Indicating that the detection signal B is equal to or lower than the upper limit threshold) (S13), the selected sensor at the time of the current sampling is the MR sensor 1B, and FIG.
In the detection signal B as shown in FIG. 7, the lower right (monotonically decreasing) portion is set to "B-" during output (S19).

If the detection signal A at the time of the current sampling is not smaller than the lower threshold value or the detection signal B at the time of the current sampling is not smaller than the upper threshold value (S13), the signal processing unit 14 sets the detection signal B at the current sampling time to It is determined whether or not the detection signal A at the time of the current sampling is smaller than the lower threshold and smaller than the upper threshold (S14). This is a step for determining whether or not the detection signals A and B are in the area b in FIG.

The signal processing section 14 determines that the detection signal B at the time of the current sampling is smaller than the lower threshold and the detection signal A at the time of the current sampling is smaller than the upper threshold (in FIG. 6, the detection signals A and B are in the region b. , Indicating that the detection signal A is equal to or less than the upper threshold) (S14), the selected sensor at the time of the current sampling is the MR sensor 1A, and FIG.
In the detection signal A as shown in FIG. 7, the upward-sloping (monotonically increasing) portion is set to "A +" during output (S20).

If the detection signal B at the time of the current sampling is not smaller than the lower threshold value or the detection signal A at the time of the current sampling is not smaller than the upper threshold value (S14), the signal processing unit 14 sets the selected sensor at the time of the previous sampling. The selected sensor is used at the time of sampling this time (S15).

Next, the signal processing section 14 determines whether or not the selected sensor at the time of the previous sampling is the MR sensor 1A and "A +" is being output during the upward-sloping (monotonically increasing) portion (S16). The selected sensor at the time of sampling is M
When R sensor 1A outputs “A +” during output of a right-upward (monotonically increasing) portion, a detection signal indicating a displacement angle from the previous sampling time to the present sampling time as an integrated steering angle until the previous sampling time. (A-sensor previous value) is added and output as a rotation angle (S21).

In this case, during the previous sampling, the MR sensor 1A is outputting a detection signal of rising to the right (monotonically increasing).
+ ", And the detection signal value A was in the range from the lower threshold to the upper threshold, so that the detection signal value A of the MR sensor 1A does not reach the nonlinear region by the time of sampling this time. Therefore, since the increase / decrease of the detection signal value means the increase / decrease of the integrated steering angle, the change of the detection signal is added to the integrated steering angle, and the change of the detection signal is calculated based on the detection signal A at the time of the current sampling. I can do it.

If the selected sensor at the time of the previous sampling is not the MR sensor 1A, and is not outputting "A +" during the output of the upwardly rising (monotonically increasing) portion (S16), the selected sensor at the time of the previous sampling is the MR sensor 1A. Sensor 1A,
It is determined whether or not "A-" is being output during the downward-sloping (monotonically decreasing) portion (S17).

If the selected sensor at the time of the previous sampling is the MR sensor 1A, and the signal processing section 14 is outputting "A-" during the lower right (monotonically decreasing) portion (S17),
The change in the detection signal indicating the displacement angle from the previous sampling time to the current sampling time (A-sensor previous value) is subtracted from the accumulated steering angle up to the previous sampling time, and the result is output as the rotation angle (S22).

In this case, during the previous sampling, the MR sensor 1A is outputting a detection signal of a downward-sloping (monotonic decrease) signal “A
Further, since the detection signal value A is in the range from the lower threshold value to the upper threshold value, the detection signal value A of the MR sensor 1A does not reach the non-linear region by the time of sampling this time. Therefore, since the increase / decrease of the detection signal value is a decrease / increase of the integrated steering angle, the change of the detection signal is subtracted from the integrated steering angle, and the change of the detection signal is calculated based on the detection signal A at the time of the current sampling. I can do it.

If the selected sensor at the time of the previous sampling is not the MR sensor 1A, and is not outputting "A-" during the lower right (monotone decreasing) portion (S17), the selected sensor at the time of the previous sampling is MR sensor 1B,
It is determined whether or not "B +" is being output during the upwardly rising (monotonically increasing) portion (S18).

When the selected sensor at the time of the previous sampling is the MR sensor 1B, and the signal processing section 14 outputs "B +" while outputting the upward-sloping (monotonically increasing) portion (S18),
The change of the detection signal indicating the displacement angle from the previous sampling time to the current sampling time (B-previous value of the sensor) is added to the integrated steering angle up to the previous sampling time and output as a rotation angle (S23).

In this case, during the previous sampling, the MR sensor 1B is outputting a detection signal of rising to the right (monotonically increasing).
+ ", And the detection signal value B is in the range from the lower threshold value to the upper threshold value. Therefore, the detection signal value B of the MR sensor 1B does not reach the nonlinear region by the time of sampling this time. Therefore, since the increase / decrease of the detection signal value means the increase / decrease of the integrated steering angle, the change of the detection signal is added to the integrated steering angle, and the change of the detection signal is calculated from the detection signal B at the time of the current sampling. I can do it.

If the selected sensor at the time of the previous sampling is not the MR sensor 1B, and is not outputting “B +” during the output of the upwardly rising (monotonically increasing) portion (S18), the selected sensor at the time of the previous sampling is the MR sensor 1B. Sensor 1B,
It is determined whether or not "B-" is being output during the downward-sloping (monotonically decreasing) portion (S24).

If the selected sensor at the time of the previous sampling is the MR sensor 1B and "B-" is being output during the lower right (monotonically decreasing) portion (S24),
The change of the detection signal indicating the displacement angle from the previous sampling time to the current sampling time (B-sensor previous value) is subtracted from the integrated steering angle up to the previous sampling time and output as the rotation angle (S31).

In this case, during the previous sampling, the MR sensor 1B is outputting a detection signal falling to the right (monotonically decreasing).
Further, since the detection signal value B is in the range from the lower threshold value to the upper threshold value, the detection signal value B of the MR sensor 1B does not reach the non-linear region by the time of sampling this time. Accordingly, since the increase / decrease of the detection signal value is a decrease / increase of the integrated steering angle, the change of the detection signal is subtracted from the integrated steering angle, and the change of the detection signal is calculated based on the detection signal B at the time of the current sampling. I can do it.

When the selected sensor at the time of the previous sampling is not the MR sensor 1B, and is not "B-" during the output of the downward-sloping (monotonically decreasing) portion, the signal processing section 14 (S2).
4) Assuming that the MR sensor has not been selected at the time of the previous sampling (S25), that is, it is at the time of starting steering,
The integrated steering angle is set to 0 and output as a rotation angle (S2
6).

Next, the signal processing unit 14 determines that the sensor selected at the time of sampling this time is the MR sensor 1A, and that the output signal is “A +” during the output of a detection signal of rising to the right (monotonically increasing), or Yes, falling to the right (monotonically decreasing)
If the detection signal is "A-" during output (S27), the "previous sensor value" to be used in the calculations (S21, 22, 23, 31) is set as the detection signal value A at the time of the current sampling (S
32), “previous selected sensor” is replaced with “currently selected sensor” (S30), and the process returns.

The signal processing section 14 determines that the sensor selected at the time of sampling this time is not the MR sensor 1A (S2
7) The sensor selected at the time of sampling this time is the MR sensor 1B, which is outputting a detection signal of rising to the right (monotonically increasing), is "B +", or is the MR sensor 1B, and is decreasing to the right (monotonically decreasing). It is determined whether the detection signal is “B−” during output (S28). If the sensor selected at the time of the current sampling is the MR sensor 1B (S28), the signal processing unit 14 detects the "previous sensor value" to be used for the calculation (S21, 22, 23, 31) at the time of the current sampling. The signal value is set to B (S33), the "previous selected sensor" is replaced with the "currently selected sensor" (S30), and the process returns.

The signal processing section 14 determines that the sensor selected at the time of sampling this time is not the MR sensor 1B (S2
8) The sensor is not selected (S29), and the "previous selected sensor" is not selected (S30), and the process returns.
In the steering angle calculation operation described above, the MR sensors 1A, 1B
Has been described, but the same operation can be performed for the MR sensors 2A and 2B.

The operation of the torque detecting device at the time of torque detection (torque calculation) will be described below with reference to the flowcharts of FIGS. However, the phase shift between the MR sensors 1A and 2A and the MR sensors 1B and 2B is an electrical angle of 90 °. Signal processing unit 1 of this torque detecting device
Reference numeral 4 first calculates and obtains the torque A = 1A-2A and the torque B = 1B-2B from the detection signals (displayed as 1A, 1B, 2A, 2B) of the MR sensors 1A, 1B, 2A, 2B ( S34).

Next, the signal processing section 14 determines that the torque A ≧ 0,
It is determined whether or not the torque B ≧ 0, the torque A ≦ 0, and the torque B ≦ 0 (S35). The signal processing unit 14 determines that the torque A ≧ 0, the torque B ≧ 0 or the torque A ≦ 0, the torque B ≦ 0
If (S35), it is determined whether or not the detection signals 1A, 1B of the MR sensors 1A, 1B satisfy 1A> 1B (S38).

The signal processing section 14 detects the detection signals 1A, 1B
If 1A> 1B (S38), the detection signals 1A, 1
Assume that B, 2A, and 2B exist in the area (a) in the waveform diagram of the detection signal shown in FIG. 10 (S39). If the detection signals 1A and 1B are not 1A> 1B (S38), the signal processing unit 14 determines that the detection signals 1A and 1B are 1A <1B.
Is determined (S40). Signal processing unit 14
If the detection signals 1A and 1B are 1A <1B (S4
0), the detection signals 1A, 1B, 2A, 2B are assumed to be present in the area (b) in the waveform diagram of the detection signals shown in FIG. 10 (S41). The signal processing unit 14 detects the detection signals 1A,
If 1B is not 1A <1B (S40), the detection signal 1
A, 1B, 2A, and 2B assume that there is no area in the waveform diagram of the detection signal shown in FIG. 10 (S42), return the detected torque to 0 (S43), and return.

If the signal processing unit 14 determines that the torques A.gtoreq.0 and the torques B.gtoreq.0 are not satisfied and the torques A.ltoreq.0 and the torques B.ltoreq.0 (S35), the detection signals 1A and 1B are set as shown in FIG. A comparison is made with the intermediate value (middle point) of the possible values of the detection signals 1A and 1B to determine whether 1A ≧ middle point and 1B ≧ middle point (S36). The signal processing unit 14 detects the detection signal 1
If A and 1B are 1A ≧ middle point and 1B ≧ middle point (S3
6) It is assumed that the detection signals 1A, 1B, 2A, 2B are present in the area (c) in the waveform diagram of the detection signal shown in FIG. 10 (S44).

The signal processing section 14 detects the detection signals 1A, 1B
Is not 1A ≧ middle point, 1B ≧ middle point (S36), the detection signals 1A, 1B are 1A ≦ middle point, 1B
It is determined whether B ≦ middle point (S37). The signal processing unit 14 determines that the detection signals 1A and 1B are 1A ≦ midpoint, 1B ≦
If it is a middle point (S37), the detection signals 1A, 1B, 2A,
2B is assumed to exist in the area (d) in the waveform diagram of the detection signal shown in FIG. 10 (S45).

The signal processing section 14 detects the detection signals 1A, 1B
Is not 1A ≦ middle point, 1B ≦ middle point (S37), the detection signals 1A, 1B are 1A ≧ middle point, 1B
It is determined whether B ≦ middle point (S46). The signal processing unit 14 determines that the detection signals 1A and 1B are 1A ≧ midpoint, 1B ≦
If it is the middle point (S46), the detection signals 1A and 2A are
It is determined whether 1A ≧ the upper threshold or 2A ≧ the upper threshold by comparing with the upper threshold such as 0 (S53).
The range of the upper threshold value and the lower threshold value described later is the detection signal 1
A, 1B, 2A, and 2B are indications of a range in which the detection signals 1A, 1B, and 2B are linear (detection signals near the connection portions of the first inclined portion 15a and the second inclined portion 15b become nonlinear).
It is set to a substantially intermediate value between the maximum value and the minimum value that can be taken by A and 2B and the middle point.

The signal processing section 14 detects the detection signals 1A, 2A
Is 1A ≧ upper limit threshold or 2A ≧ upper limit threshold (S5
3) It is assumed that the detection signals 1A, 1B, 2A, 2B exist in the area (e) in the waveform diagram of the detection signal as shown in FIG. 10 (S58). In this case, the region (e) does not exist in FIG. 10, but it occurs when the steered wheel 1 is rotated in the reverse direction. The signal processing unit 14 detects the detection signal 1
If A and 2A are not 1A ≧ upper limit threshold and 2A ≧ upper limit threshold (S53), the detection signals 1B and 2B are output as shown in FIG.
It is determined whether 1B ≦ lower threshold or 2B ≦ lower threshold by comparing with a lower threshold such as 0 (S54).

The signal processing section 14 detects the detection signals 1B, 2B
Is 1B ≦ lower threshold or 2B ≦ lower threshold (S5
4) It is assumed that the detection signals 1A, 1B, 2A, and 2B exist in the area (f) in the waveform diagram of the detection signal shown in FIG. 10 (S59). The signal processing unit 14 detects the detection signal 1B,
If 2B is not 1B ≦ lower threshold and 2B ≦ lower threshold (S54), the detection signals 1A, 1B, 2A, 2B
Determines that there is no area in the waveform diagram of the detection signal shown in FIG. 10 (S55), sets the detected torque to 0 (S51), and returns.

The signal processing section 14 detects the detection signals 1A, 1B
Is not 1A ≧ middle point, 1B ≦ middle point (S46), the detection signals 1A, 1B are 1B ≧ middle point, 1B
It is determined whether or not A ≦ middle point (S47). The signal processing unit 14 determines that the detection signals 1A and 1B are 1B ≧ midpoint, 1A ≦
If it is not the middle point (S47), the detection signals 1A, 1B, 2
A and 2B are waveform diagrams of the detection signal shown in FIG.
If no area exists (S52), the detected torque is set to 0 (S51), and the process returns.

The signal processing section 14 detects the detection signals 1A, 1B
If 1B ≧ middle point and 1A ≦ middle point (S47), whether the detection signals 1B and 2B satisfy 1B ≧ upper threshold or 2B ≧ upper threshold as compared with the upper threshold as shown in FIG. It is determined whether or not it is (S48). The signal processing unit 14 detects the detection signal 1
If B and 2B are 1B ≧ upper limit threshold or 2B ≧ upper limit threshold (S48), it is determined that the detection signals 1A, 1B, 2A and 2B exist in the area (g) in the waveform diagram of the detection signal shown in FIG. (S56).

The signal processing section 14 detects the detection signals 1B, 2B
Is not 1B ≧ upper limit threshold and 2B ≧ upper limit threshold (S48), the detection signals 1A and 2A are compared with the lower limit threshold as shown in FIG.
It is determined whether it is the lower threshold (S49). If the detection signals 1A and 2A are 1A ≦ lower threshold or 2A ≦ lower threshold (S49), the signal processor 14 detects the detection signals 1A and 1A.
It is assumed that B, 2A and 2B exist in the area (h) in the waveform diagram of the detection signal shown in FIG. 10 (S57). still,
In this case, although the region (h) does not exist in FIG. 10, it occurs when the steered wheels are rotated in the opposite direction.

The signal processing section 14 detects the detection signals 1A, 2A
Is not 1A ≦ lower threshold and 2A ≦ lower threshold (S49), the detection signals 1A, 1B, 2A and 2B are
In the detection signal waveform diagram shown in FIG. 10, it is assumed that there is no area (S50), and the detected torque is set to 0 (S50).
51) Return.

Next, the signal processing section 14 calculates (S34) the torque A = 1A-2A and the torque B = 1B-2.
The magnitudes of the absolute values | torque A | and | torque B | of B are compared (S60). The signal processing unit 14 determines that | torque A | ≧ | torque B | is satisfied (S60), and the areas where the detection signals 1A, 1B, 2A, and 2B are determined to exist in the previous steps are defined as areas ((a) ) Or area ((d),
If (f)) (S61), the detection signals 1A, 1B, 2
It is assumed that the area where A and 2B truly exist is the area (j) in the waveform diagram of the detection signal shown in FIG. 11, and the detected torque is returned as the torque A (S62).

The signal processing unit 14 determines that | torque A | ≧ | torque B | (S60), and determines that the detection signals 1A, 1B, 2A, and 2B exist in the respective steps up to this point. If it is not any of the areas (S6
1) The region where the detection signals 1A, 1B, 2A and 2B truly exist is the region (k) in the waveform diagram of the detection signal shown in FIG. 11, and the detected torque is defined as -torque A (S65). To return.

The signal processing unit 14 determines that the area where the detection signals 1A, 1B, 2A, and 2B existed in each step up to now is not the area (the area where the | torque A | ≧ | torque B | (A)) or area ((c),
(G)) (S63), the detection signals 1A, 1B, 2
The region where A and 2B truly exist is the region (m) in the waveform diagram of the detection signal shown in FIG. 11, and the detected torque is returned as the torque B (S64).

The signal processing unit 14 determines that the area where the detection signals 1A, 1B, 2A, and 2B exist in each step up to here is not | torque A | ≧ | torque B | If it is not any of the areas (S6
3) The region where the detection signals 1A, 1B, 2A and 2B truly exist is the region (n) in the waveform diagram of the detection signal shown in FIG. 11, and the detected torque is defined as -torque B (S66). To return.

The operation of the torque detector at the time of backup will be described below with reference to the flowchart of FIG. The signal processing unit 14 of the torque detection device detects an abnormality in the detection signals (displayed as 1A, 1B, 2A, 2B) of the MR sensors 1A, 1B, 2A, 2B (S
70), if two or more abnormal detection signals are found (S71), the failure of the torque detection device is determined (S7).
2), the steering assist motor and the steering mechanism are disconnected, and a fail process for notifying the driver of the occurrence of a failure with an alarm lamp or the like is executed (S73), and the process returns.

The signal processing section 14 detects the detection signals 1A, 1B,
An abnormality is detected in 2A and 2B (S70), and the detected abnormal detection signal is one system (S71). If the abnormal detection signal is the detection signal 1A (S74), the detection signal 1A is converted to the detection signal 2A. (S79), an error is notified to the driver by an alarm lamp or the like (S73a), and the process returns. That is, M including the MR sensor 1A in which the abnormality has occurred
The torque detected by the pair of R sensors 1A and 2A is set to 0, and M
The torque detected by the pair of R sensors 1B and 2B is used.

The signal processing section 14 determines whether the detected abnormal detection signal is one system (S71), the abnormal detection signal is not the detection signal 1A (S74), and the abnormal detection signal is the detection signal 1B. If (S75), the detection signal 1B is replaced with the detection signal 2B (S80), the driver is notified of an abnormality by an alarm lamp or the like (S73a), and the process returns.
That is, the detected torque by the pair of MR sensors 1B and 2B including the MR sensor 1B in which the abnormality has occurred is set to 0, and the detected torque by the pair of MR sensors 1A and 2A is used.

The signal processing section 14 finds that the detected abnormal detection signal is one system (S71), and the abnormal detection signal is not the detection signal 1A or the detection signal 1B (S74, 75).
If the abnormal detection signal is the detection signal 2A (S7
6) The detection signal 2A is replaced with the detection signal 1A (S8).
1) The abnormality is notified to the driver by an alarm lamp or the like (S73a), and the process returns. In other words, M
The detected torque by the pair of MR sensors 1A and 2A including the R sensor 2A is set to 0, and the detected torque by the pair of MR sensors 1B and 2B is used.

The signal processing unit 14 detects one abnormal detection signal in one system (S71), and the abnormal detection signal is neither the detection signal 1A, the detection signal 1B nor the detection signal 2A (S74, 75, 76) If the abnormal detection signal is the detection signal 2B (S77), the detection signal 2B is replaced with the detection signal 1B (S78), the driver is notified of the abnormality by an alarm lamp or the like (S73a), and the process returns.
That is, the detected torque by the pair of MR sensors 1B and 2B including the MR sensor 2B in which the abnormality has occurred is set to 0, and the detected torque by the pair of MR sensors 1A and 2A is used.

The operation of the torque detecting device when detecting the torque (calculating the torque) when the phase shift between the MR sensors 1A and 2A and the MR sensors 1B and 2B is set to an electrical angle of 120 ° will be described below. 7 will be described with reference to FIGS. First, the signal processing unit 14 of the torque detecting device first includes the MR sensors 1A, 1B, 2A, 2B
The torque A = 1A-2A and the torque B = 1B-2B are calculated by the respective detection signals (displayed as 1A, 1B, 2A, 2B) (S34).

Next, the signal processing unit 14 determines that the torque A ≧ 0,
It is determined whether or not the torque B ≧ 0, the torque A ≦ 0, and the torque B ≦ 0 (S35). The signal processing unit 14 determines that the torque A ≧ 0, the torque B ≧ 0 or the torque A ≦ 0, the torque B ≦ 0
If (S35), it is determined whether or not the detection signals 1A, 1B of the MR sensors 1A, 1B satisfy 1A> 1B (S38).

The signal processing section 14 detects the detection signals 1A, 1B
If 1A> 1B (S38), the detection signals 1A, 1
It is assumed that B, 2A, and 2B exist in the area (a) in the waveform diagram of the detection signal shown in FIG. 13 (S39). If the detection signals 1A and 1B are not 1A> 1B (S38), the signal processing unit 14 determines that the detection signals 1A and 1B are 1A <1B.
Is determined (S40). Signal processing unit 14
If the detection signals 1A and 1B are 1A <1B (S4
0), the detection signals 1A, 1B, 2A, 2B are assumed to be present in the area (b) in the waveform diagram of the detection signals shown in FIG. 13 (S41). The signal processing unit 14 detects the detection signals 1A,
If 1B is not 1A <1B (S40), the detection signal 1
A, 1B, 2A and 2B determine that there is no area in the waveform diagram of the detection signal shown in FIG. 13 (S42), set the detected torque to 0 (S43), and return.

If the torque A.gtoreq.0 and the torque B.gtoreq.0 are not satisfied and the torque A.ltoreq.0 and the torque B.ltoreq.0 are not satisfied (S35), the signal processing section 14 outputs the detection signals 1A and 1B as shown in FIG. A comparison is made with the intermediate value (middle point) of the possible values of the detection signals 1A and 1B to determine whether 1A ≧ middle point and 1B ≧ middle point (S36). The signal processing unit 14 detects the detection signal 1
If A and 1B are 1A ≧ middle point and 1B ≧ middle point (S3
6) It is assumed that the detection signals 1A, 1B, 2A, 2B are present in the area (c) in the waveform diagram of the detection signals shown in FIG. 13 (S44).

The signal processing section 14 detects the detection signals 1A, 1B
Is not 1A ≧ middle point, 1B ≧ middle point (S36), the detection signals 1A, 1B are 1A ≦ middle point, 1B
It is determined whether B ≦ middle point (S37). The signal processing unit 14 determines that the detection signals 1A and 1B are 1A ≦ midpoint, 1B ≦
If it is a middle point (S37), the detection signals 1A, 1B, 2A,
It is assumed that 2B exists in the area (d) in the waveform diagram of the detection signal shown in FIG. 13 (S45).

The signal processing section 14 detects the detection signals 1A, 1B
Is not 1A ≦ middle point, 1B ≦ middle point (S37), the detection signals 1A, 1B are 1A ≧ middle point, 1B
It is determined whether B ≦ middle point (S46). The signal processing unit 14 determines that the detection signals 1A and 1B are 1A ≧ midpoint, 1B ≦
If it is the middle point (S46), the detection signals 1A and 2A are
It is determined whether 1A ≧ upper threshold or 2A ≧ upper threshold by comparing with the upper threshold shown in FIG. 3 (S53).
The range of the upper threshold value and the lower threshold value described later is the detection signal 1
A, 1B, 2A, and 2B are indications of a range in which the detection signals 1A, 1B, and 2B are linear (detection signals near the connection portions of the first inclined portion 15a and the second inclined portion 15b become nonlinear).
It is set to a substantially intermediate value between the maximum value and the minimum value that can be taken by A and 2B and the middle point.

The signal processing section 14 detects the detection signals 1A, 2A
Is 1A ≧ upper limit threshold or 2A ≧ upper limit threshold (S5
3) It is assumed that the detection signals 1A, 1B, 2A, 2B exist in the area (e) in the waveform diagram of the detection signal as shown in FIG. 13 (S58). If the detection signals 1A and 2A are not 1A ≧ upper threshold and 2A ≧ upper threshold (S53), the signal processor 14 compares the detection signals 1B and 2B with the lower threshold as shown in FIG. It is determined whether 1B ≦ lower threshold or 2B ≦ lower threshold (S5
4).

The signal processing section 14 detects the detection signals 1B, 2B
Is 1B ≦ lower threshold or 2B ≦ lower threshold (S5
4) It is assumed that the detection signals 1A, 1B, 2A, 2B are present in the area (f) in the waveform diagram of the detection signals shown in FIG. 13 (S59). The signal processing unit 14 detects the detection signal 1B,
If 2B is not 1B ≦ lower threshold and 2B ≦ lower threshold (S54), the detection signals 1A, 1B, 2A, 2B
Determines that there is no area in the waveform diagram of the detection signal shown in FIG. 13 (S55), sets the detected torque to 0 (S51), and returns.

The signal processing section 14 detects the detection signals 1A, 1B
Is not 1A ≧ middle point, 1B ≦ middle point (S46), the detection signals 1A, 1B are 1B ≧ middle point, 1B
It is determined whether or not A ≦ middle point (S47). The signal processing unit 14 determines that the detection signals 1A and 1B are 1B ≧ midpoint, 1A ≦
If it is not the middle point (S47), the detection signals 1A, 1B, 2
A and 2B are waveform diagrams of the detection signal shown in FIG.
If no area exists (S52), the detected torque is set to 0 (S51), and the process returns.

The signal processing section 14 detects the detection signals 1A, 1B
If 1B ≧ middle point and 1A ≦ middle point (S47), whether the detection signals 1B and 2B satisfy 1B ≧ upper threshold or 2B ≧ upper threshold as compared with the upper threshold as shown in FIG. It is determined whether or not it is (S48). The signal processing unit 14 detects the detection signal 1
If B and 2B are 1B ≧ upper limit threshold or 2B ≧ upper limit threshold (S48), it is determined that the detection signals 1A, 1B, 2A and 2B exist in the area (g) in the waveform diagram of the detection signal shown in FIG. (S56).

The signal processing section 14 detects the detection signals 1B, 2B
However, if 1B ≧ the upper threshold is not satisfied and 2B ≧ the upper threshold is not satisfied (S48), the detection signals 1A and 2A are compared with the lower threshold as shown in FIG.
It is determined whether or not ≦ lower threshold (S49). If the detection signals 1A and 2A are 1A ≦ lower threshold value or 2A ≦ lower threshold value (S49), the signal processing unit 14 outputs the detection signals 1A and 2A.
It is assumed that 1B, 2A and 2B exist in the area (h) in the waveform diagram of the detection signal shown in FIG. 13 (S57).

The signal processing section 14 detects the detection signals 1A, 2A
Is not 1A ≦ lower threshold and 2A ≦ lower threshold (S49), the detection signals 1A, 1B, 2A and 2B are
In the waveform diagram of the detection signal shown in FIG. 13, it is assumed that there is no area (S50), and the detected torque is set to 0 (S50).
51) Return.

Next, the signal processing section 14 calculates (S34) the torque A = 1A-2A and the torque B = 1B-2.
The magnitudes of the absolute values | torque A | and | torque B | of B are compared (S60). The signal processing unit 14 determines that | torque A | ≧ | torque B | is satisfied (S60), and the areas where the detection signals 1A, 1B, 2A, and 2B are determined to exist in the previous steps are defined as areas ((a) ) Or area ((d),
If (f)) (S61), the detection signals 1A, 1B, 2
The region where A and 2B truly exist is the region (j) in the waveform diagram of the detection signal shown in FIG. 14, and the detected torque is returned as the torque A (S62).

The signal processing unit 14 determines that | torque A | ≧ | torque B | (S60), and determines that the areas where the detection signals 1A, 1B, 2A, and 2B exist in the previous steps are the areas and If it is not any of the areas (S6
1) The region where the detection signals 1A, 1B, 2A and 2B truly exist is the region (k) in the waveform diagram of the detection signal shown in FIG. 14, and the detected torque is defined as -torque A (S65). To return.

The signal processing unit 14 determines that the area where the detection signals 1A, 1B, 2A, and 2B exist in the respective steps up to this point is not | torque A | ≧ | torque B | (S60). (A)) or area ((c),
(G)) (S63), the detection signals 1A, 1B, 2
The region where A and 2B truly exist is the region (m) in the waveform diagram of the detection signal shown in FIG. 14, and the detected torque is returned as the torque B (S64).

The signal processing unit 14 determines that the areas where the detection signals 1A, 1B, 2A, and 2B exist in the previous steps are not | torque A | ≧ | torque B | (S60). If it is not any of the areas (S6
3) The region where the detection signals 1A, 1B, 2A and 2B truly exist is the region (n) in the waveform diagram of the detection signal shown in FIG. 14, and the detected torque is defined as -torque B (S66). To return.

Embodiment 2 FIG. 15 is a schematic diagram schematically illustrating a configuration of a rotation angle detection device and a torque detection device according to a second embodiment of the present invention. The rotation angle detection device and the torque detection device are MR sensors 1A, 1B, 2A,
Each detection signal output in accordance with the part of the target 15 detected by the 2B (magnetoresistive element, magnetic sensor) is given to the signal processing unit 14a, and the signal processing unit 14a
Converts the given detection signals from analog to digital, and stores tables 14aa, 14a for each of the built-in detection signals.
b, 14ba, and 14bb (storage means). Tables 14aa, 14ab, 14ba, 14bb
Are EPRs arranged in a matrix so as to output digital signals corresponding to the input digital signals, respectively.
OM (Erasable and Programmable ROM).

The tables 14aa, 14ab, 14ba,
14bb stores the characteristics of the detected parts and the detected signals of the MR sensors 1A, 1B, 2A and 2B in correspondence with the characteristics of the detected parts and the detected signal to be output during the manufacture and assembly of the torque detecting device. deep. Tables 14aa, 14a
b, 14ba, 14bb are MR sensors 1A, 1B, 2
When A and 2B each detect a part, a detection signal (digital signal) to be output is output according to each output detection signal (digital signal).

In particular, the tables 14aa and 14ab
When the R sensors 1A and 1B are switched, the detection signal values to be output do not shift and the switching can be performed smoothly.
When the sensors 2A and 2B are switched, the detection signals of the MR sensors 1A, 1B, 2A and 2B are corrected so that the detected signal values to be output do not shift and can be switched smoothly. The signal processing unit 14a includes a table 14a
The operation of the signal processing unit 14 described in the first embodiment is executed using the detection signals of the MR sensors 1A, 1B, 2A, and 2B corrected by a, 14ab, 14ba, and 14bb. Other configurations and operations of the rotation angle detection device and the torque detection device are the same as those of the rotation angle detection device and the torque detection device described in the first embodiment, and a description thereof will not be repeated.

Embodiment 3 FIG. 16 is a principle view showing a main configuration of a torque detecting device according to a third embodiment of the present invention. This torque detecting device shows a case where the torque detecting device is used for a steering device. An upper shaft 21 (input) of a steering shaft (steering shaft) having a steering wheel 1 connected to an upper end and a torsion bar 25 connected to a lower end. A projection 22 (projection) made of a magnetic material is provided spirally along the peripheral surface of the intermediate portion of the shaft.

When the upper shaft 21 rotates, the upper shaft 21
An MR sensor 1A (a magnetoresistive element, a first magnetic sensor) is provided in parallel with the upper shaft 21 with an appropriate gap in order to detect the position of the protrusion 22 made of a magnetic material that moves in the axial direction. It is fixed to a part where the body does not move.
Also, the MR sensor 1A detects a position that should be 180 ° different in the circumferential direction of the upper shaft 21 from the position detected by the MR sensor 1A.
The sensor 1B (third magnetic sensor) is provided in parallel with the upper shaft 21 with an appropriate gap, and is fixed to a portion where the vehicle body does not move.

The lower shaft 23 (output shaft) of the steering shaft has an upper end connected to the torsion bar 25 and a lower end connected to the pinion 26. Like the upper shaft 21, a protrusion 24 (protrusion) made of a magnetic material is provided spirally along the peripheral surface of the intermediate portion of the lower shaft 23. Also,
When the lower shaft 23 rotates, the MR sensor 2A (second magnetic sensor) is provided with an appropriate clearance from the lower shaft 23 in order to detect the position of the protrusion 24 made of a magnetic material that moves in the axial direction of the lower shaft 23. Are provided in parallel with a space between them, and are fixed to a part where the vehicle body does not move.

The MR sensor 2B (fourth magnetic sensor) is provided with an appropriate clearance from the lower shaft 23 so that the position detected by the MR sensor 2A should differ from the position detected by 180 ° in the circumferential direction of the lower shaft 23. Are provided in parallel with a space between them, and are fixed to a part where the vehicle body does not move. MR sensors 1A, 1B, 2
A and 2B indicate that the output voltage of the MR sensors 1A and 2A becomes the same when no torque is generated on the upper shaft 21 and the lower shaft 23 (when the coupling shaft is not twisted),
The output voltages of the MR sensors 1B and 2B are set to be the same.

Each of the MR sensors 1A, 1B, 2A and 2B includes, for example, a voltage dividing circuit composed of two magnetic resistances and a bias magnet provided on the side not facing the steering shaft. The bias magnet enhances the magnetic field on the surface of the steering shaft in order to increase the change in the magnetic field due to the protrusions 22 and 24 made of a magnetic material and increase the sensitivity of the MR sensors 1A, 1B, 2A and 2B. M
Each output voltage of the R sensors 1A, 1B, 2A, 2B is supplied to a signal processing unit 30 for processing, and the output signal of the signal processing unit 30 is a steering torque applied to the steering wheel 1 detected by the torque detection device. Is output as a signal indicating

Hereinafter, the operation of the torque detecting device having such a configuration will be described with reference to the flowcharts of FIGS. This torque detecting device is configured such that the MR sensor 1A, 1B and 2A, 2B respond to rotation of the upper shaft 21 and the lower shaft 23 in the range of 0 ≦ θ <360 °.
22 and 2 made of a magnetic material closest to the detection surface of
4 moves in the axial direction of the upper shaft 21 and the lower shaft 23.
Since the protrusions 22 and 24 made of a magnetic material are spirally provided along the peripheral surfaces of the upper shaft 21 and the lower shaft 23,
Upper shaft 21 and lower shaft 23 of protrusions 22 and 24 closest to the detection surfaces of MR sensors 1A, 1B and 2A, 2B.
And the rotation angles of the upper shaft 21 and the lower shaft 23 can be made to correspond to each other.

If the steering torque is applied to the steering wheel 1 and the torsion bar 25 has a twist angle, the output voltages of the MR sensors 1A and 2A become
A voltage difference corresponding to the twist angle occurs, and the MR sensor 1B
Similarly, a voltage difference corresponding to the torsion angle occurs in each output voltage of the signal processing unit 3B and the signal processing unit 3B.
By calculating with 0, the torsion angle is obtained, and a signal indicating the steering torque can be output.

First, the signal processing unit 30
A, 1B, 2A, 2B output voltages MR1A, MR1
B, MR2A and MR2B are converted from analog to digital (S82). Here, the signal processing unit 30 is configured as shown in FIG.
As shown in the figure, each output voltage MR1A, MR1B (MR2A, MR2B) of the MR sensor 1A, 1B (2A, 2B).
The upper and lower levels L for switching the output voltages MR1A, MR1B (MR2A, MR2B) so that the output voltages MR1A, MR1B (MR2A, MR2B) can be switched in a portion where the effective data (linear portion)
IMH and LIML are set. Each output voltage MR1
Assume that valid data portions (linear portions) of A and MR1B (MR2A and MR2B) are parallel to each other.

Next, the signal processing section 30 sets the MR sensor 1A
It is determined whether the output voltage MR1A is higher than the level LIMH or the output voltage MR1A is lower than the level LIML (S83). As a result, if any, the MR sensor 1B is moved to the upper shaft 21 (input shaft) side. Is determined as an MR sensor used for torque detection (S84), and its output is determined and stored as an output voltage MR1B (S85).

The signal processing unit 30 determines whether the output voltage MR1A of the MR sensor 1A is higher than the level LIMH or whether the output voltage MR1A is lower than the level LIML (S83). It is determined whether the output voltage MR1B is higher than the level LIMH or the output voltage MR1B is lower than the level LIML (S86). As a result, if any, the MR sensor 1A is connected to the upper shaft 21 (input shaft). , Is determined as an MR sensor used for torque detection (S87), and its output is determined and stored as an output voltage MR1A (S88).

The signal processing unit 30 determines whether the output voltage MR1B of the MR sensor 1B is higher than the level LIMH or whether the output voltage MR1B is lower than the level LIML (S86). It is determined whether the MR sensor on the upper shaft 21 (input shaft) side used in the cycle is the MR sensor 1A (S8).
9). As a result, if the previous time was the MR sensor 1A, the MR sensor 1A is determined as the MR sensor on the upper shaft 21 (input shaft) side used for torque detection (S8).
7).

The signal processing section 30 determines whether or not the MR sensor on the upper shaft 21 (input shaft) side used in the previous torque detection cycle is the MR sensor 1A (S89).
As a result, when it is not the MR sensor 1A, the M on the upper shaft 21 (input shaft) side used in the previous torque detection cycle is used.
It is determined whether or not the R sensor is the MR sensor 1B (S90). As a result, when the previous time was the MR sensor 1B, the MR sensor 1B was moved to the upper shaft 21 (input shaft) side.
Determined as MR sensor used for torque detection (S8
4).

The signal processing section 30 includes an upper shaft 21 (input shaft).
When the output of the MR sensor used for torque detection on the side is determined to be the output voltage MR1B (S85), or when the upper shaft 21
When the output of the MR sensor used for torque detection on the side is determined to be the output voltage MR1A (S88), the MR sensor 2A
It is determined whether the output voltage MR2A is higher than the level LIMH or the output voltage MR2A is lower than the level LIML (S91). As a result, if any, the MR sensor 2B is moved to the lower shaft 23 (output shaft) side. Is determined as an MR sensor used for torque detection (S92), and its output is determined and stored as an output voltage MR2B (S93).

The signal processing section 30 determines whether the output voltage MR2A of the MR sensor 2A is higher than the level LIMH or whether the output voltage MR2A is lower than the level LIML (S91). It is determined whether the output voltage MR2B is higher than the level LIMH or the output voltage MR2B is lower than the level LIML (S94). As a result, if any, the MR sensor 2A is moved to the lower shaft 23 (output shaft) side. Is determined as an MR sensor used for torque detection (S95), and its output is determined and stored as an output voltage MR2A (S96).

The signal processor 30 determines whether the output voltage MR2B of the MR sensor 2B is higher than the level LIMH or whether the output voltage MR1B is lower than the level LIML (S94). It is determined whether the MR sensor on the lower shaft 23 (output shaft) side used in the cycle is the MR sensor 2A (S9).
7). As a result, if the previous time was the MR sensor 2A, the MR sensor 2A is determined as the MR sensor used for torque detection on the lower shaft 23 (output shaft) side (S9).
5).

The signal processing section 30 determines whether or not the MR sensor on the lower shaft 23 (output shaft) side used in the previous torque detection cycle is the MR sensor 2A (S97).
As a result, when it is not the MR sensor 2A, the M of the lower shaft 23 (output shaft) used in the previous torque detection cycle is used.
It is determined whether or not the R sensor is the MR sensor 2B (S98). As a result, when the previous time was the MR sensor 2B, the MR sensor 2B was moved to the lower shaft 23 (output shaft) side.
Determined as the MR sensor used for torque detection (S9
2).

Next, the signal processing unit 30 determines whether the MR sensor to be used for torque detection on the upper shaft 21 (input shaft) side has been determined (Sensor 1 ≠ A∩Sensor 1 ≠ B) or the lower shaft Is the MR sensor used for torque detection on the 23 (output shaft) side determined (Sensor 2 ≠ A∩Sensor 2 ≠ B)
Is determined (S99), and when the determination result is that one or both MR sensors are not determined ((sensor 1 決定 A∩sensor 1 ≠ B) ∪ (sensor 2 ≠ A∩sensor 2 ≠ B)) Outputs a signal with the detected torque as 0 (S10
4).

This is because there is an MR sensor that outputs an output voltage higher than the level LIMH or an output voltage lower than the level LIML on one or both of the upper shaft 21 (input shaft) and the lower shaft 23 (output shaft). (S83, 86,
91, 94), and there is no MR sensor used in the previous torque detection cycle (S90, 98), and the MR sensor used for torque detection cannot be determined.

If there is an MR sensor that outputs an output voltage higher than the level LIMH or an output voltage lower than the level LIML, as shown in FIG.
The R sensor can be determined as an MR sensor used for torque detection, and even when there is no MR sensor that has output an output voltage higher than the level LIMH or an output voltage lower than the level LIML, the previous torque detection cycle If the MR sensor used at that time exists (S8
9, 90, 97, 98) and subsequently the MR sensor can be used for torque detection.

The signal processing unit 30 includes an upper shaft 21 (input shaft)
The MR sensor used for torque detection is determined on the side, and the MR sensor used for torque detection on the lower shaft 23 (output shaft) side is determined ((sensor 1 = A∪sensor 1
= B) ∩ (sensor 2 = A∪sensor 2 = B)), torque = output voltage of MR sensor on input shaft side−M on output shaft side
The output voltage of the R sensor is calculated (S100).

Next, the signal processor 30 determines whether the MR sensor used for torque detection is the MR sensor 1A on the upper shaft 21 (input shaft) side and the MR sensor 2A on the lower shaft 23 (output shaft) side. Alternatively, it is determined whether the upper shaft 21 side is the MR sensor 1B and the lower shaft 23 side is the MR sensor 2B (S101), and if any of them, that is, all of the MR sensors used for torque detection are: When the output shaft is on the same side with respect to the upper shaft 21 and the lower shaft 23 and has the same output characteristics as shown in FIG. 20A, the detected torque is displayed as a shift on the same output characteristics. From
No torque correction is required, and the calculated torque (S100)
Is output as the detected torque.

The signal processing section 30 makes the determination (S101).
When the result is neither of these, that is, when the MR sensor used for torque detection is an MR sensor on the upper shaft 21 (input shaft) side
The sensor 1A, the lower shaft 23 (output shaft) side is the MR sensor 2B, or the upper shaft 21 side is the MR sensor 1B
When the lower shaft 23 side is the MR sensor 2A (S
101), it is determined whether or not the output voltage of the input shaft side MR sensor is higher than the output voltage of the output shaft side MR sensor (S1).
02), when the input shaft side is larger, a preset voltage value T is subtracted from the calculated torque (S100) to perform torque correction (S103), and the corrected torque is output as the detected torque. .

The signal processing section 30 determines whether or not the output voltage of the MR sensor on the input shaft side is higher than the output voltage of the MR sensor on the output shaft side (S102). The torque correction is performed by adding a preset voltage value T to the torque (S100) (S105), and the corrected torque is output as the detected torque. The two MR sensors used for torque detection are the upper shaft 21
When the input shaft and the lower shaft 23 (output shaft) are on different sides from each other (S101), as shown in FIG. The difference is a voltage value T corresponding to 180 ° in the circumferential direction of the shaft 21 and the lower shaft 23).

Therefore, when the output voltage of the MR sensor on the input shaft side is higher than the output voltage of the MR sensor on the output shaft side (S
102) and FIG. 20 (b), the upper shaft 21 (input shaft) side is the MR sensor 1A, and the lower shaft 23 (output shaft) side is M
Since it is the R sensor 2B, the output voltage M of the MR sensor 2B
The voltage value T is added to R2B, converted into the output voltage MR2A of the MR sensor 2A, and the torque is corrected (S103).
On the other hand, the output voltage of the MR sensor on the input shaft
When the output voltage is smaller than the output voltage of the R sensor (S102), FIG.
From 0 (b), since the input shaft side is the MR sensor 1B and the output shaft side is the MR sensor 2A, the voltage value T is added to the output voltage MR1B of the MR sensor 1B to obtain the MR sensor 1A.
Is converted to the output voltage MR1A, and the torque is corrected (S1
05).

Embodiment 4 FIGS. 21 to 26 are flowcharts showing the operation of the torque detecting device according to the fourth embodiment of the present invention. The configuration of this torque detecting device is the same as the configuration of the torque detecting device described in the third embodiment (FIG. 16), and thus the description is omitted. However, MR sensor 1
The difference between the positions to be detected by A and 1B and the difference between the positions to be detected by MR sensors 2A and 2B need not be 180 ° in the circumferential direction of upper shaft 21 and lower shaft 23, respectively. A predetermined distance may exist in the axial direction of the upper shaft 21 and the lower shaft 23, respectively.

Hereinafter, the operation of the torque detecting device will be described with reference to the flowcharts of FIGS.
In this torque detecting device, the upper shaft 21 and the lower shaft 23
In accordance with the rotation in the range of 0 ≦ θ <360 °, the protrusions 22 and 24 made of a magnetic material closest to the detection surfaces of the MR sensors 1A, 1B and 2A, 2B are attached to the upper shaft 21 and the lower shaft 23. Move in the axial direction. The protrusions 22 and 24
Since it is spirally provided along the peripheral surfaces of the upper shaft 21 and the lower shaft 23, the upper shaft 21 of the protrusions 22 and 24 which are closest to the detection surfaces of the MR sensors 1A, 1B and 2A, 2B.
In addition, the axial position of the lower shaft 23 and the rotation angle of the upper shaft 21 and the lower shaft 23 can correspond to each other.

Here, if the steering torque is applied to the steering wheel 1 and the torsion bar 25 is twisted, the output voltages of the MR sensors 1A and 2A become
A voltage difference corresponding to the twist angle occurs, and the MR sensor 1B
Similarly, a voltage difference corresponding to the torsion angle occurs in each output voltage of the signal processing unit 3B and the signal processing unit 3B.
By calculating with 0, the torsion angle is obtained, and a signal indicating the steering torque can be output.

First, the signal processing unit 30
A, 1B, 2A, 2B output voltages MR1A, MR1
B, MR2A, and MR2B are converted from analog to digital (S106). Here, the signal processing unit 30 is configured as shown in FIG.
As shown in (b)), the MR sensors 1A, 1B (2A,
2B) output voltages MR1A, MR1B (MR2A, M
R2B) within the portion where the valid data (linear portion) overlaps,
Upper and lower levels LIMH and LIML for the switching are set so that the output voltages MR1A and MR1B (MR2A and MR2B) can be switched. It is assumed that the effective data portions (linear portions) of the output voltages MR1A and MR1B (MR2A and MR2B) are parallel to each other.

Next, the signal processing section 30 sets the MR sensor 1A
Is determined whether the output voltage MR1A is higher than the level LIMH or the output voltage MR1A is lower than the level LIML (S107). As a result, if any, the upper shaft 21 ( Input shaft)
It is determined whether or not the MR sensor on the side is the MR sensor 1A (S108). As a result, if the previous time was the MR sensor 1A, it is determined whether or not the output voltage MR1A of the MR sensor 1A is higher than the level LIMH (S109). If the output voltage MR1A is higher, the conversion for conversion is performed. Voltage value T1BA = MR1A-MR1B is calculated and stored (S110). If the output voltage MR1A is smaller (S109), the voltage value T1AB for conversion = MR1B-
The MR 1A is calculated and stored (S113).

Next, the signal processing section 30 sets the MR sensor 1B
Is the M of the upper shaft 21 (input shaft) used for torque detection.
It is determined as an R sensor (S111), and its output is determined and stored as an output voltage MR1B (S112). Upper shaft 21
When the MR sensor used for torque detection changes from 1A to 1B, the output voltages differ by a voltage value corresponding to the difference between the positions to be detected, and therefore need to be converted. Therefore, when the output voltage MR1A of the MR sensor 1A is higher than the level LIMH (S109), FIG.
From (a), a voltage value T1BA for conversion is calculated and stored. On the other hand, the output voltage MR1A of the MR sensor 1A
Is smaller than the level LIMH (S109), that is, when the output voltage MR1A is smaller than the level LIML, a voltage value T1AB to be converted is calculated from FIG. 27A and stored.

The signal processing unit 30 determines that the MR sensor on the upper shaft 21 (input shaft) side used in the previous torque detection cycle is not the MR sensor 1A (S108). When the sensor is not switched, there is no need for conversion, and the MR sensor 1B is connected to the upper shaft 2
The first side is determined as an MR sensor used for torque detection (S111), and its output is determined and stored as an output voltage MR1B (S112).

The signal processing unit 30 determines whether the output voltage MR1A of the MR sensor 1A is higher than the level LIMH or whether the output voltage MR1A is lower than the level LIML (S107).
It is determined whether the output voltage MR1B is higher than the level LIMH or whether the output voltage MR1B is lower than the level LIML (S114). As a result, if any, the upper shaft 21 ( Input shaft)
It is determined whether or not the MR sensor on the side is the MR sensor 1B (S115). As a result, if the previous time was the MR sensor 1B, it is determined whether or not the output voltage MR1B of the MR sensor 1B is higher than the level LIMH (S116). If the output voltage MR1B is higher, conversion for conversion is performed. The voltage value T1AB = MR1B-MR1A is calculated and stored (S117). When the output voltage MR1B is smaller (S116), the voltage value T1BA for conversion = MR1A-
The MR1B is calculated and stored (S122).

Next, the signal processing section 30 sets the MR sensor 1A
Is the M of the upper shaft 21 (input shaft) used for torque detection.
It is determined as an R sensor (S118), and its output is determined and stored as an output voltage MR1A (S119). Upper shaft 21
When the MR sensor used for detecting the torque changes from 1B to 1A, the output voltages differ from each other by a voltage value corresponding to the difference between the positions to be detected. Therefore, when the output voltage MR1B of the MR sensor 1B is higher than the level LIMH (S116), FIG.
From (a), the voltage value T1AB for conversion is calculated and stored. On the other hand, the output voltage MR1B of the MR sensor 1B
Is smaller than the level LIMH (S116), that is, when the output voltage MR1B is smaller than the level LIML, a voltage value T1BA to be converted is calculated from FIG. 27A and stored.

The signal processing section 30 determines whether or not the output voltage MR1B of the MR sensor 1B is higher than the level LIMH or lower than the level LIML (S114). MR of upper shaft 21 (input shaft) used during cycle
It is determined whether or not the sensor is the MR sensor 1A (S
120). As a result, if the previous time was the MR sensor 1A, the MR sensor 1A is determined as the MR sensor used for torque detection on the upper shaft 21 (input shaft) side (S11).
8).

The signal processing unit 30 determines whether or not the MR sensor on the upper shaft 21 (input shaft) side used in the previous torque detection cycle is the MR sensor 1A (S12).
0) As a result, when it is not the MR sensor 1A, it is determined whether or not the MR sensor on the upper shaft 21 (input shaft) side used in the previous torque detection cycle is the MR sensor 1B (S121). As a result, if the previous time was the MR sensor 1B, the MR sensor 1B is determined as the MR sensor on the upper shaft 21 (input shaft) side used for torque detection (S111).

The signal processing section 30 determines whether or not the MR sensor on the upper shaft 21 (input shaft) side used in the previous torque detection cycle was the MR sensor 1B (S12).
1) As a result, when it is not the MR sensor 1B, whether the MR sensor to be used for torque detection on the upper shaft 21 (input shaft) side has not been determined (sensor 1 ≠ A∩sensor 1 ≠ B),
Alternatively, it is determined whether the MR sensor used for torque detection on the lower shaft 23 (output shaft) side is determined (Sensor 2 ≠ A ≠ Sensor 2 ≠ B) (S139).

The signal processing unit 30 includes an upper shaft 21 (input shaft)
When the output of the MR sensor used for torque detection on the side is determined to be the output voltage MR1B (S112), or when the upper shaft 2
When the output of the MR sensor used for torque detection on the 1 (input shaft) side is determined to be the output voltage MR1A (S119),
It is determined whether the output voltage MR2A of the MR sensor 2A is higher than the level LIMH or the output voltage MR2A is lower than the level LIML (S123). As a result, if any, the lower part used in the previous torque detection cycle is determined. It is determined whether or not the MR sensor on the shaft 23 (output shaft) is the MR sensor 2A (S124).

The signal processing unit 30 determines that the previous MR sensor
As a result of determining whether or not the sensor is the R sensor 2A (S124), if the previous time was the MR sensor 2A, it is determined whether or not the output voltage MR2A of the MR sensor 2A is higher than the level LIMH (S125). When the voltage MR2A is larger, the voltage value T2BA for conversion = MR2A-M
R2B is calculated and stored (S126). If the output voltage MR2A is smaller (S125), a voltage value T2AB = MR2B-MR2A for conversion is calculated and stored (S129).

Next, the signal processing unit 30
To the lower shaft 23 (output shaft), which is used for torque detection.
It is determined as an R sensor (S127), and its output is determined and stored as an output voltage MR2B (S128). Lower shaft 23
When the MR sensor used for detecting the torque is switched from 2A to 2B, the output voltages differ from each other by a voltage value corresponding to the difference between the positions to be detected.

Accordingly, the output voltage MR2 of the MR sensor 2A is
When A is greater than level LIMH (S125), FIG.
7 (b), a voltage value T2BA for conversion is calculated and stored (S126). On the other hand, when the output voltage MR2A of the MR sensor 2A is lower than the level LIMH (S1
25) That is, when the output voltage MR2A is smaller than the level LIML, the voltage value T2AB for conversion is calculated and stored from FIG. 27B (S129).

The signal processing unit 30 determines that the MR sensor on the lower shaft 23 (output shaft) side used in the previous torque detection cycle is not the MR sensor 2A (S124). When the sensor is not switched, there is no need for conversion, and the MR sensor 2B is connected to the lower shaft 2
The third side is determined as an MR sensor used for torque detection (S127), and its output is determined and stored as an output voltage MR2B (S128).

The signal processing unit 30 determines whether the output voltage MR2A of the MR sensor 2A is higher than the level LIMH or whether the output voltage MR2A is lower than the level LIML (S123).
It is determined whether the output voltage MR2B is higher than the level LIMH or the output voltage MR2B is lower than the level LIML (S130). As a result, if any, the lower shaft 23 ( Output shaft)
It is determined whether or not the MR sensor on the side is the MR sensor 2B (S131). As a result, if the previous time was the MR sensor 2B, it is determined whether or not the output voltage MR2B of the MR sensor 2B is higher than the level LIMH (S132). If the output voltage MR2B is higher, conversion for conversion is performed. The voltage value T2AB = MR2B-MR2A is calculated and stored (S133). When the output voltage MR2B is smaller (S132), the voltage value T2BA for conversion = MR2A-
The MR2B is calculated and stored (S138).

Next, the signal processing unit 30 sets the MR sensor 2A
To the lower shaft 23 (output shaft), which is used for torque detection.
It is determined as an R sensor (S134), and its output is determined and stored as an output voltage MR2A (S135). Lower shaft 23
When the MR sensor used for detecting the torque is switched from 2B to 2A, the output voltages differ from each other by a voltage value corresponding to the difference between the positions to be detected.

Accordingly, the output voltage MR2 of the MR sensor 2B
When B is larger than the level LIMH (S132), FIG.
7 (b), a voltage value T2AB for conversion is calculated and stored (S133). On the other hand, when the output voltage MR2B of the MR sensor 2B is lower than the level LIMH (S1
32), that is, when the output voltage MR2B is lower than the level LIML, a voltage value T2BA for conversion is calculated and stored from FIG. 27B (S138).

The signal processor 30 determines whether the output voltage MR2B of the MR sensor 2B is higher than the level LIMH or whether the output voltage MR2B is lower than the level LIML (S130). MR of lower shaft 23 (output shaft) used during cycle
It is determined whether or not the sensor is the MR sensor 2A (S
136). As a result, if the previous time was the MR sensor 2A, the MR sensor 2A is determined as the MR sensor used for torque detection on the lower shaft 23 (output shaft) side (S13).
4).

The signal processing unit 30 determines whether or not the MR sensor on the lower shaft 23 (output shaft) side used in the previous torque detection cycle was the MR sensor 2A (S13).
6) If it is not the MR sensor 2A, it is determined whether the MR sensor on the lower shaft 23 (output shaft) side used in the previous torque detection cycle is the MR sensor 2B (S137). As a result, if the previous time was the MR sensor 2B, the MR sensor 2B is determined as the MR sensor used for torque detection on the lower shaft 23 (output shaft) side (S127).

Next, the signal processing unit 30 determines whether the MR sensor to be used for torque detection on the upper shaft 21 (input shaft) side has been determined (Sensor 1 ≠ A∩Sensor 1 ≠ B) or the lower shaft Is the MR sensor used for torque detection on the 23 (output shaft) side determined (Sensor 2 ≠ A∩Sensor 2 ≠ B)
(S139), and when the result of the determination is that one or both MR sensors have not been determined ((Sensor 1 ≠ A ≠ Sensor 1 ≠ B) ∪ (Sensor 2 ≠ A∩Sensor 2 ≠ B)) Outputs a signal with the detected torque set to 0 (S14).
5).

This is because there is an MR sensor that outputs an output voltage higher than the level LIMH or an output voltage lower than the level LIML on one or both of the upper shaft 21 (input shaft) and the lower shaft 23 (output shaft). (S107, S107
4, 123, 130), and there is no MR sensor used in the previous torque detection cycle (S121, 13).
7) The case where the MR sensor used for torque detection cannot be determined.

If there is an MR sensor which has output an output voltage higher than the level LIMH or an output voltage lower than the level LIML, the signal processing section 30 (a) of FIG.
As shown in (b), the other MR sensor can be determined as the MR sensor used for torque detection. Further, even when there is no MR sensor that has output an output voltage higher than the level LIMH or an output voltage lower than the level LIML, if the MR sensor used in the previous torque detection cycle exists, the MR sensor is used.
Subsequently, it can be determined as an MR sensor used for torque detection.

The signal processing unit 30 includes an upper shaft 21 (input shaft)
The MR sensor used for torque detection is determined on the side, and the MR sensor used for torque detection on the lower shaft 23 (output shaft) side is determined ((sensor 1 = A∪sensor 1
= B) ∩ (sensor 2 = A∪sensor 2 = B)), torque = output voltage of MR sensor on input shaft side−M on output shaft side
The output voltage of the R sensor is calculated (S140).

Next, the signal processing unit 30 determines whether the MR sensor used for torque detection is the MR sensor 1A on the upper shaft 21 (input shaft) side and the MR sensor 2A on the lower shaft 23 (output shaft) side. Alternatively, it is determined whether the upper shaft 21 side is the MR sensor 1B and the lower shaft 23 side is the MR sensor 2B (S141). If any of them, the MR sensors used for torque detection are the MR sensors 1A and 2A. Is determined (S146). As a result, when the MR sensors used for torque detection are the MR sensors 1A and 2A, that is, both of the MR sensors used for torque detection are on the same side with respect to the upper shaft 21 and the lower shaft 23,
As shown in FIGS. 27 (a) and 27 (b), when the output characteristics are the same, the detected torque is displayed as a deviation on the same output characteristic, so that no torque correction is required, and the calculated torque (S140) is output as the detected torque.

The signal processing section 30 determines whether or not the MR sensors used for torque detection are the MR sensors 1A and 2A (S146). The result is not the MR sensors 1A and 2A but the MR sensors 1B and 2B. , The voltage value T1BA calculated in advance (S110) is added to the calculated torque (S140), and the voltage value T2BA calculated in advance (S126) is subtracted to perform torque correction (S14).
7) The corrected torque is output as the detected torque.

The signal processing section 30 makes the determination (S141).
When the result is neither of these, that is, when the MR sensor used for torque detection is an MR sensor on the upper shaft 21 (input shaft) side
The sensor 1A, the lower shaft 23 (output shaft) side is the MR sensor 2B, or the upper shaft 21 side is the MR sensor 1B
When the lower shaft 23 side is the MR sensor 2A (S
141), it is determined whether the MR sensor used for torque detection is the MR sensor 1A on the upper shaft 21 side (S1).
42).

The signal processing unit 30 includes an MR sensor used for torque detection, and the upper shaft 21 (input shaft) side having the MR sensor 1.
If it is A (S142), it is determined whether or not the output voltage of the MR sensor on the upper shaft 21 side is higher than the output voltage of the MR sensor on the lower shaft 23 (output shaft) side (S143).
When the value on the 1 side is larger, the calculated torque (S140)
Then, the torque value is corrected by subtracting the voltage value T2BA calculated in advance (S126) (S144), and the corrected torque is output as the detected torque.

The signal processing section 30 includes an upper shaft 21 (input shaft).
It is determined whether the output voltage of the MR sensor on the side of the lower shaft 23 is higher than the output voltage of the MR sensor on the side of the lower shaft 23 (output shaft) (S14).
3) When the lower shaft 23 is larger, the torque is corrected by adding the voltage value T2AB calculated in advance (S129) to the calculated torque (S140) (S151), and the corrected torque is detected. Is output as the adjusted torque.

The signal processing unit 30 includes an MR sensor used for torque detection, and the upper shaft 21 (input shaft) having the MR sensor 1
A is determined (S142), and when the upper shaft 21 side is not the MR sensor 1A, that is, when the upper shaft 21 side is M
If it is the R sensor 1B, it is determined whether the output voltage of the MR sensor on the upper shaft 21 side is higher than the output voltage of the MR sensor on the lower shaft 23 (output shaft) side (S148).
When the side is larger, the calculated torque (S140)
The torque value is corrected by subtracting the voltage value T1AB calculated in advance (S113) (S149), and the corrected torque is output as the detected torque.

The signal processing unit 30 includes an upper shaft 21 (input shaft)
It is determined whether the output voltage of the MR sensor on the side of the lower shaft 23 is higher than the output voltage of the MR sensor on the side of the lower shaft 23 (output shaft) (S14).
8) When the lower shaft 23 is larger, the torque is corrected by adding the voltage value T1BA calculated in advance (S110) to the calculated torque (S140) (S150), and the corrected torque is detected. Is output as the adjusted torque.

When the two MR sensors used for torque detection are either or both of the MR sensors 1B and 2B, the output voltages MR1B and MR2 of the MR sensors 1B and 2B
B is the output voltage MR1A, MR of the MR sensor 1A, 2A.
Convert to 2A.

The upper shaft 21 (input shaft) side is the MR sensor 1
A, when the lower shaft 23 (output shaft) side is the MR sensor 2B (S142) and the output voltage of the upper shaft 21 side MR sensor is higher than the output voltage of the lower shaft 23 side MR sensor (S143), FIG. a) From FIG.
By adding the voltage value T2BA to the output voltage MR2B of B, M
The output voltage is converted into the output voltage MR2A of the R sensor 2A (S14).
4). The upper shaft 21 side is the MR sensor 1A and the lower shaft 23 side is the MR sensor 2B (S142).
When the output voltage of the R sensor is lower than the output voltage of the MR sensor on the output shaft side (S143), the voltage value T2A is added to the output voltage MR2B of the MR sensor 2B from FIGS.
B is subtracted and converted into the output voltage MR2A of the MR sensor 2A (S151).

The upper shaft 21 (input shaft) side is the MR sensor 1
B, when the lower shaft 23 (output shaft) side is the MR sensor 2A (S142) and the output voltage of the input shaft side MR sensor is higher than the output voltage of the output shaft side MR sensor (S14)
3) From FIG. 27 (a) and (b), the voltage value T1AB is subtracted from the output voltage MR1B of the MR sensor 1B, and the output voltage MR1A of the MR sensor 1A is converted. The input shaft side is the MR sensor 1B and the output shaft side is the MR sensor 2A (S14).
2) The output voltage of the MR sensor on the input shaft side is M
When the output voltage is smaller than the output voltage of the R sensor (S143), FIG.
7 (a) and 7 (b), the output voltage MR1 of the MR sensor 1B is determined.
B is added to the voltage value T1BA to convert it to the output voltage MR1A of the MR sensor 1A.

The upper shaft 21 (input shaft) side is the MR sensor 1B
When the lower shaft 23 (output shaft) side is the MR sensor 2B (S146), the voltage value T1BA is added to the output voltage MR1B of the MR sensor 1B from FIGS. Of the output voltage MR1A
The voltage value T2BA is added to the output voltage MR2B of the sensor 2B and converted into the output voltage MR2A of the MR sensor 2A (S147).

Incidentally, in this case, T1BA + T1AB
= T2BA + T2AB = a voltage value (constant) corresponding to 360 °, so that the output voltage MR1B of the MR sensor 1B
Is subtracted from the voltage value T1AB to convert the voltage value into an output voltage MR1A of the MR sensor 1A.
When the voltage value T2AB is subtracted from B and converted into the output voltage MR2A of the MR sensor 2A, the voltage values T1BA, T2BA
The result is the same as when each is converted using.
That is, from FIGS. 27A and 27B, the calculated torque (S
140), a voltage value T1 calculated in advance (S113).
AB is subtracted, and the voltage value T calculated in advance (S129)
Even if the torque correction is performed by adding 2AB, the torque value after the correction is the same as the case where the torque correction is performed as described above (S147).

In the fourth embodiment of the torque detecting device according to the present invention described above, the difference between the positions to be detected between the MR sensor 1A and the MR sensor 1B, and the difference between the MR sensor 2A and the MR sensor 2B
The difference between the position to be detected and the upper shaft 21 and the lower shaft 23
Even if the angle is not exactly 180 ° in the circumferential direction, the torque can be detected with high accuracy.

[0209] Embodiment 5 FIG. 28 is a principle diagram showing a main configuration of a torque detecting device according to a fifth embodiment of the present invention. This torque detecting device includes MR sensors 1A, 1B,
Each output voltage output in accordance with the position detected by each of the 2A and 2B (magnetoresistive element, magnetic sensor) is applied to the signal processing unit 30a, and the signal processing unit 30a converts the applied output voltage into an analog signal. The tables 30aa, 30ab, 30ba, 30a,
30bb (storage means). Table 3
0aa, 30ab, 30ba, 30bb are EPROM (Erasable) arranged in a matrix so as to output digital signals corresponding to the input digital signals.
and Programmable ROM).

Tables 30aa, 30ab, 30ba,
30bb stores the characteristics of the detection position and the output voltage of the MR sensors 1A, 1B, 2A, and 2B, and the characteristics of the detection position and the voltage to be output, in association with each other at the time of manufacturing and assembling the torque detection device. . Tables 30aa, 30ab,
30ba, 30bb are MR sensors 1A, 1B, 2A,
When each of the 2Bs detects a position, a voltage value (digital signal) to be output is output according to each output voltage value (digital signal).

In particular, the tables 30aa and 30ab
When switching the R sensors 1A and 1B, the voltage values to be output do not shift, and the switching can be performed smoothly. The tables 30ba and 30bb are used when switching the MR sensors 2A and 2B. There is no deviation in the voltage value to be output, and it is possible to switch smoothly.
Each output voltage of the MR sensors 1A, 1B, 2A, 2B is corrected. The signal processing unit 30a includes tables 30aa, 30a
MR sensors 1A, 1 corrected by b, 30ba, 30bb
The operation of the signal processing unit 30 described in the third and fourth embodiments is executed using the output voltages of B, 2A, and 2B. Other configurations and operations of the torque detection device are the same as the configurations and operations of the torque detection devices described in the third and fourth embodiments, and a description thereof will be omitted.

Embodiment 6 FIG. FIG. 29 is a longitudinal sectional view showing a main part configuration of a sixth embodiment of the steering device according to the present invention. This steering device has a steering wheel 1 at the upper end.
The upper shaft 33 is provided with a cylindrical input shaft 35 via a first dowel pin 34.
The upper end of a connecting shaft 36 (torsion bar) inserted inside the connecting shaft 36 is connected. A cylindrical output shaft 38 is connected to a lower end of the connection shaft 36 via a second dowel pin 37, and the upper shaft 33, the input shaft 35, and the output shaft 3
8 are rotatably supported in the housing 32 via bearings 39, 40, 31 respectively.

In the housing 32, the connecting shaft 3
6, a torque detecting device 43 for detecting a steering torque based on a relative displacement between an input shaft 35 and an output shaft 38 connected via
And a speed reduction mechanism 45 that reduces the rotation of a steering assist electric motor 44 that is driven based on the detection result of the torque detection device 43 and transmits the rotation to the output shaft 38, according to the rotation of the steering wheel 1. The operation of the steering mechanism is assisted by the rotation of the electric motor 44 to reduce the labor burden on the driver for steering. Output shaft 38
Is connected to a rack and pinion type steering mechanism via a universal joint.

The torque detecting device 43 is provided with a projection 43c (projection) made of a magnetic material spirally along the peripheral surface 43a of the input shaft 35. In order to detect the position of the protrusion 43c made of a magnetic material that moves in the axial direction of the shaft 35, the MR sensor 46a
(A magnetoresistive element, a first magnetic sensor) is provided in parallel with the input shaft 35 with an appropriate gap, and the MR sensor 46a
M at a position that should differ from the input shaft 35 by 180 ° in the circumferential direction.
An R sensor 46b (third magnetic sensor) is provided in parallel with the input shaft 35 with an appropriate gap, and is fixed to a portion where the vehicle body does not move.

As with the input shaft 35, the output shaft 38 is provided with a projection 43d (projection) made of a magnetic material spirally along the peripheral surface 43b of the output shaft 38. Output shaft 3
In order to detect the position of the protrusion 43d made of a magnetic material that moves in the axial direction of the output shaft 38 when the
A sensor 47a (third magnetic sensor) is provided in parallel with the output shaft 38 with an appropriate gap, and an MR sensor 47b (fourth magnetic sensor) is provided at a position that is 180 ° different from the MR sensor 47a in the circumferential direction of the output shaft 38. Sensors) are provided in parallel with the output shaft 38 with an appropriate gap therebetween, and are fixed to portions where the vehicle body does not move.

The operation of the steering device having such a configuration will be described below. When the input shaft 35 and the output shaft 38 rotate without twisting the connection shaft 36, the input shaft 35, the output shaft 38, and the connection shaft 36 rotate integrally. As the input shaft 35 and the output shaft 38 rotate, the MR sensors 46a and 46a
The protrusions 43c and 43d made of a magnetic material and closest to the detection surfaces b and 47a and 47b move in the axial direction of the input shaft 35 and the output shaft 38. Projections 43c and 43d
Are the peripheral surfaces 43a and 43b of the input shaft 35 and the output shaft 38.
Are provided spirally along the MR sensor 46.
a, 46b and 47a, 47b, the input shaft 35 of the protrusions 43c and 43d made of magnetic material closest to each other.
The position of the output shaft 38 in the axial direction can correspond to the rotation angles of the input shaft 35 and the output shaft 38.

For example, the MR sensors 46a, 46b and 4
7a and 47b, the input shaft 35 and the output shaft 3
8 is set so as to have the same linear relationship with each rotation angle (steering angle), and by rotating the input shaft 35 and the output shaft 38 a plurality of times, the MR sensors 46a, 46b and 47
Each output of a and 47b shows a voltage waveform in a 360 ° cycle, and the rotation angles of the input shaft 35 and the output shaft 38 can be detected by the output voltages of the MR sensors 46a and 46b and 47a and 47b, respectively.

A steering torque is applied to the steering wheel 1, and the connecting shaft 36 is twisted to make the input shaft 35 and the output shaft 38
Is rotated, the MR sensor 46a, 4
Each of the output voltages 6b and 47a, 47b has a voltage difference corresponding to the twist angle. MR sensors 46a, 46
b and the respective output voltages of 47a and 47b are applied to a signal processing unit (not shown) through each output cable, and the signal processing unit includes the signal processing unit 1 described in the first to fifth embodiments.
As in the case of 4, 14a, 30, and 30a, the torsion angle is obtained by calculating the voltage difference, and a signal corresponding to the steering torque is output.

Embodiment 7 FIG. FIG. 31 is a schematic diagram showing a configuration of a torque detection device according to the present invention applied to a steering device of an automobile. As shown, an input shaft (first shaft) 16 having an upper end connected to a steered wheel (steering wheel) 1;
An output shaft (second shaft) 17 having a lower end connected to a pinion 18 of a steering mechanism is coaxially connected via a small-diameter torsion bar 19 to communicate the steering wheel 1 with the steering mechanism. A steering shaft (rotating shaft) 13 is configured, and the torque detecting device according to the present invention is configured as follows near a connection portion between the input shaft 16 and the output shaft 17.

[0220] A disk-shaped target plate 12 is coaxially fixed to the input shaft 16 near the end on the side of connection with the output shaft 17, and the outer peripheral surface of the target plate 12 is
A plurality (10 in the figure) of targets 10, 10,...
Are juxtaposed. These targets 10, 10 ...
As shown in the drawing, each of the projections is made of a magnetic material in the form of a partial spiral which is inclined at substantially the same angle with respect to the axial direction of the input shaft 16 on which the target plate 12 is fitted. Are arranged side by side at equal intervals in the circumferential direction.

The same target plate 12 is externally fitted and fixed also in the vicinity of the end of the output shaft 17 on the connection side with the input shaft 16, and the output shaft 17 on which the output shaft 17 is fitted is mounted on the outer periphery of the target plate 12. A plurality of targets 10, 10... Each of which are inclined at substantially the same angle with respect to the axial length direction are arranged in parallel with the targets 10, 10.

Two sensor boxes 11a, 11b are arranged outside the target plates 12, 12 so as to face the outer edges of the respective targets 10, 10,... ing. These sensor boxes 11a and 11b are connected to the input shaft 16 and the output shaft 17 respectively.
Is fixedly supported on a stationary part such as a housing for supporting the housing.

Inside the sensor box 11a, a magnetic sensor 1A facing the targets 10, 10,... On the input shaft 16 side and a magnetic sensor 2A facing the targets 10, 10,. The magnetic sensors 1B facing the targets 10, 10... On the input shaft 16 side, and the targets 10, 1 on the output shaft 17 side are also accommodated inside the sensor box 11b.
And the magnetic sensor 2B opposing to... Are stored with their circumferential positions aligned.

Each of the magnetic sensors 1A, 2A, 1B, 2B uses an element such as a magnetoresistive element (MR element) having a characteristic in which an electric characteristic (resistance) changes by the action of a magnetic field, and responds to a change in a peripheral magnetic field. The sensor is configured to change the output voltage by using these outputs V ₁ , V ₂ , v ₁ , v ₂
Is drawn out of the sensor boxes 11a and 11b,
It is provided to an arithmetic processing unit 14 using a microprocessor.

FIG. 32 shows the magnetic sensors 1A, 2A, 1B,
It is explanatory drawing which shows an example of a change aspect of the output voltage of 2B.
The horizontal axis in the figure indicates the rotation angle of the input shaft 16 or the output shaft 17, and the solid lines in the figure indicate the magnetic sensors 1A, 1A on the input shaft 16 side.
B, the output voltages of the magnetic sensors 2A, 2B on the output shaft 17 side are shown by broken lines, respectively.

The targets 10, 10... To which the magnetic sensors 1A, 2A, 1B, 2B face each other have a predetermined inclination angle on the outer periphery of the input shaft 16 and the output shaft 17 with respect to the axial direction, as described above. The protrusions are made of a magnetic material and are juxtaposed. On the other hand, the length of each target 10, 10,...
Alternatively, each target 1 is limited in the circumferential direction of the output shaft 17.
There is a discontinuous portion between 0, 10. Therefore, when the input shaft 16 and the output shaft 17 rotate around the axis, the magnetic sensors 1A, 2A, 1B, 2B cause the input shaft 16 or the output shaft 17 to rotate while the corresponding targets 10, 10,. A voltage signal that changes linearly according to the change in the rotation angle is output, and changes non-linearly according to the change in the rotation angle while the discontinuous portion between the adjacent targets 10 passes. Outputs a voltage signal.

As a result, the magnetic sensors 1A, 2A, 1B,
The output voltage of 2B is, as shown in FIG.
Area that changes linearly while 0 passes (linear change area)
And a region that changes nonlinearly during the passage of the discontinuous portion (nonlinear change region). The cycle of this repetition corresponds to the number of targets 10 arranged on the outer periphery of the target plate 12, and as described above, when ten targets 10 are arranged on the outer periphery of the target plate 12, The repetition is performed when the input shaft 16 or the output shaft 17
The rotation occurs by 6 ° (= 360 ° / 10) as one cycle.

Here, when attention is paid to a change in the output of the magnetic sensor 1A on the input shaft 16 side and a change in the output of the magnetic sensor 2A on the output shaft 17 that matches the magnetic sensor 1A in the circumferential direction, these are shown in FIG. And has a predetermined phase shift. This shift amount corresponds to the difference (relative angular displacement) between the rotation angles of the input shaft 16 and the output shaft 17. This relative angular displacement is caused by the rotation of the input shaft 16 and the output shaft under the action of the rotation torque applied to the input shaft 16. Torsion bar 19 connecting to
Corresponding to the torsion angle generated. Therefore, the magnetic sensor 1A
The rotation torque applied to the input shaft 16 can be calculated based on the difference ΔV (= V ₁ −V ₂ ) between the output voltage V ₁ of the magnetic sensor 2A and the output voltage V ₂ of the magnetic sensor 2A.

A similar phase shift also occurs between the output of the other magnetic sensor 1B on the input shaft 16 side and the output of the other magnetic sensor 2B on the output shaft 17 side. It is also possible to calculate based on the output difference Δv (= v ₁ −v ₂ ) generated between the sensor 1B and the magnetic sensor 2B.

In the illustrated embodiment, the targets 10 and 10 are connected to an input shaft (first shaft) 16 and an output shaft (second shaft) 17 connected via a torsion bar 19 whose torsion characteristics are clear. Are described, but when the target is a rotating shaft whose torsion characteristic is clear, the targets 10 and 1 are located at positions separated in the axial direction of the rotating shaft.
.. May be directly provided, and the rotational torque may be calculated based on the output difference of the magnetic sensors arranged to face each other.

The calculation of the rotational torque as described above is performed in the arithmetic processing unit 14 to which the output voltages of the magnetic sensors 1A, 2A, 1B, 2B are applied. The calculation procedure is described in Japanese Patent Application No. 11-100665 by the present applicant.
No., etc., and the description is omitted here.

Here, two magnetic sensors 1 are provided outside the targets 10 on the input shaft 16 and the output shaft 17, respectively.
The reason why A, 1B and 2A, 2B are juxtaposed is to prevent the erroneous calculation of the rotational torque using the uncertain output obtained in the nonlinear change region shown in FIG. The two magnetic sensors 1A and 2A in one sensor box 11a and the two magnetic sensors 1B and 2B in the other sensor box 11b are shifted in phase by about a half cycle in the circumferential direction of each target plate 12. As shown in FIG. 32, when one of the two outputs is in the non-linear change region, the other two outputs are in the linear change region.

In the arithmetic processing section 14, the magnetic sensor 1
One of the A and 2A and the magnetic sensors 1B and 2B in the linear change region is selected, and the rotational torque is calculated based on the output difference on the selected side. The feature of the torque detection device according to the present invention lies in this selection operation.

FIG. 33 is a flowchart showing the contents of the selection operation of the magnetic sensor. This operation is performed as an interruption process during the calculation of the rotational torque performed at predetermined sampling intervals. First, the output difference ΔV between the magnetic sensors 1A and 2A and the output difference Δv between the magnetic sensors 1B and 2B are calculated (step 152).

Next, the sign of the calculated output differences ΔV and Δv is checked (steps 153, 159). If both signs are the same, that is, if both are positive or both are negative, the flow proceeds to step 154. If the signs are different, the process proceeds to step 158 described below without performing the following operation.

In step 154, the arithmetic processing unit 14
Are the output differences ΔV and Δv calculated in step 152
Are calculated (step 154), and then the magnetic sensors 1A, 2A and 1B, 2
It is checked which of B is being selected, that is, whether it is being used for the calculation of the rotational torque at the present time (step 155).
If the magnetic sensors 1A and 2A are being selected, the process proceeds to step 156, and to step 160 where the magnetic sensors 1B and 2B are being selected, respectively, and the non-selected magnetic sensor is determined from the absolute value of the output difference of the selected magnetic sensor. A magnitude comparison between a difference obtained by subtracting the absolute value of the sensor output difference and a preset reference value δ is performed.

As a result of the magnitude comparison in step 156 or step 160, the absolute value of the output difference of the selected magnetic sensor is smaller than the absolute value of the output difference of the non-selected magnetic sensor, exceeding the reference value. If it is determined that the current magnetic sensor selection is changed (step 157),
If it is determined that the value is not lower than the value, the process proceeds to step 158 while maintaining the current magnetic sensor selection. In step 158, it is determined whether or not a predetermined operation end condition such as a power shutdown is satisfied, and the above steps 152 to 157, 159, and 16 are performed until the operation end condition is satisfied.
0 operation is repeated.

With the above operation, the positive / negative judgment of the output difference of the selected magnetic sensor and the output difference of the non-selected magnetic sensor is performed (steps 153, 159). The magnitude comparison between the absolute value of the output difference of the selected magnetic sensor and the absolute value of the output difference of the non-selected magnetic sensor is performed (steps 156 and 160), and as a result of this comparison, the former replaces the latter. The switching from the selected magnetic sensor to the non-selected magnetic sensor is performed only when it is determined that the value is lower than the fixed amount (reference value δ).

The meaning of the above selection operation will be described with reference to FIG. In FIG. 32, when the rotation angle of the input shaft 31 increases, the output voltages of the magnetic sensors 1A, 2A and 1B, 2B repeat the linear change region and the non-linear change region as described above toward the right of the drawing. Change. Here, X in the figure
_In the first section shown as 1, the rotation torque is calculated using the output difference ΔV between the magnetic sensors 1A and 2A in the linear change region.

[0240] In the second half of the first interval X _1, magnetic sensor 1A in the selection, the output of the 2A, a phenomenon that decreases the rate of change of each along with the access to the non-linear change region occurs, both magnetic As described above, the outputs of the sensors 1A and 2A change with a phase shift under the action of the rotational torque.
One magnetic sensor (magnetic sensor 1A in FIG. 32)
The rate of change of is preceded. Thus the magnetic sensors 1A, output difference ΔV of 2A decreases as reaching the first end of the interval X _1.

[0241] On the other hand, in the second half of X ₁ of the first section, the magnetic sensor 1B of the non-selected, the output of the 2B also in linear change region. However this linear change region, the magnetic sensor 1A in the selection, has a phase shift of half a period with respect to the non-linear variation region of 2A, also includes near end of the first segment X _1. Therefore, the non-selected magnetic sensor 1
B, the output difference 2B Delta] v is not changed at the end near the X ₁ of the first section.

At this time, based on the result of the magnitude comparison of the absolute value of the output difference performed in step 156, the magnetic sensors 1A and 2A being selected and the magnetic sensors 1B and 2B not being selected are determined.
Switching to 2B is made, after which in the second section X _2, magnetic sensors 1B to continue the linear change region, 2B
Is calculated using the output difference Δv.

[0243] The above-described switching is after made the second section magnetic sensor 1A in the X within _2, examining the state of change in the output of the 2A, the output curve of one of the magnetic sensors 1A to shift earlier to the non-linear change region There the section Y ₁ to intersect the output curve of the other magnetic sensor 2A, then the magnetic sensor 1A, 2
Magnitude of the output of A converted, a section Y ₂ in which the output of the magnetic sensor 2A comes to exceed the output of the magnetic sensor 1A,
Again the magnetic sensors 1A, the output curves intersect magnetic sensor 1A of the 2A, the magnitude relationship between the output of 2A is subdivided into the sections Y ₃ to reconversion.

Of these, in the section Y ₁ , the magnitude relation of the absolute value of the output difference is maintained as it is, and the magnetic sensor 1 B, 2B selection is maintained.

On the other hand, in the section Y ₂ , since the rate of change of the outputs of the magnetic sensors 1 A and _{2 A} in the non-linear change region is large, the output difference ΔV between the magnetic sensors 1 B and 2 B currently selected is When the output difference Δv becomes larger and the magnitude comparison in step 160 is executed,
Proceeding to step 157, there is a risk that switching to the magnetic sensors 1A and 2A in the non-linear change region may be made. However, in the section Y _2, the magnetic sensor 1B in the selection, whereas the output difference 2B is positive, the magnetic sensor 1A of the non-selected, has become the output difference 2A is negative, the step 153 And the result of the positive / negative determination in step 159,
Since the processes in steps 154 to 157 and 160 are not performed, the selection of the magnetic sensors 1B and 2B is maintained as it is.

Further, in the section Y ₃ , the magnitude relationship between the outputs of the non-selected magnetic sensors 1 A and 2 A is changed again, and the comparison is performed in step 160. In this section Y ₃ , the magnetic sensors 1 A and 2 A are compared. The output of 2A re-enters the linear transition region. Accordingly, the absolute value | ΔV | of the output difference between the non-selected magnetic sensors 1A and 2A is determined by the selected magnetic sensor 1B and
The absolute value | Δv | of the output difference of 2B does not greatly exceed, and as a result of the comparison in step 160, the magnetic sensors 1B,
The selection of 2B is kept as it is.

[0247] Such magnetic sensors 1B, 2B selection of approaches the end of the second segment X _2, one of the magnetic sensors 2
A is switched when the output of A is ready to shift to the non-linear change region, and thereafter, the magnetic sensors 1B, 2B
Is calculated using the output difference ΔV.

The output of the magnetic sensor 1A, 2A or the output of the magnetic sensor 1B, 2B is reduced by the differentiation of each output since the rate of change is reduced as described above before the selection is switched. It is also effective to directly determine and perform the same switching on condition that this rate of change is equal to or less than a predetermined value.

However, in this method, the absolute value of the rate of change is affected by the magnitude of the rate of change in each linear change area, and the rate of change in the linear change area is determined by the rotation axis (steering axis 13) to be controlled. Of the steering shaft 13 whose rotation speed is not constant because it changes according to the magnitude of the rotation speed of the steering shaft 13.
When it is used for calculating the rotational torque, there is a possibility that erroneous switching may be performed. Therefore, the switching by the differential value is
On condition that the rotation speed of the steering shaft 13 is within a predetermined range, it is preferable to stop the rotation as an auxiliary operation of the above-described selection operation. However, in the detection of the rotation torque of a general rotation shaft having a small change in the rotation speed, switching can be mainly used based on the differential value.

FIG. 34 shows magnetic sensors 1A, 2A, 1B,
FIG. 33 is an explanatory diagram showing another example of a change aspect of the output voltage of the magnetic sensors 1A, 2A, 1B, and 2B when a rotation torque in a direction opposite to that of FIG. 32 is applied. The situation is shown.

In this case, the output of the magnetic sensors 1A and 2A
The magnitude relation and the magnitude relation of the magnetic sensors 1B and 2B are different.
The magnetic sensors 1A and 2A or the magnetic sensors
The selection of the air sensors 1B and 2B is performed. In FIG. 34,
First section X as in FIG.₁, The second section X_TwoAnd the third ward
Interval X_ThreeAre shown, and the first section X₁And the third section X _Three
In, the magnetic sensors 1A and 2A are selected and
The rotation torque is calculated using the output difference ΔV,
2 sections X_Two, The magnetic sensors 1B and 2B are selected.
The output torque Δv is used to calculate the rotational torque.
Done.

The above selection operation is performed based on the result of comparison between the output of the selected magnetic sensor and the output of the non-selected magnetic sensor. Therefore, when the output characteristics of each magnetic sensor change due to the influence of the ambient temperature. Even if there is, the magnetic sensor in the linear change region can be correctly selected. Therefore, in the arithmetic processing unit 14, at any time during the operation, the magnetic sensor in the linear change region is correctly selected, and a highly accurate rotation torque is calculated using the detection result, and the steering based on the calculation result is performed. Various controls, such as control of an auxiliary motor, can be favorably performed.

In the above-described embodiment, an example of application to an application for detecting a rotational torque (steering torque) of a steering shaft 13 that connects a steered wheel 1 and a steering mechanism in a steering apparatus of an automobile. As described above, it goes without saying that the torque detecting device according to the present invention can be widely used in all applications for detecting the rotational torque of the rotating shaft.

[0254]

According to the rotation angle detecting device according to the first, fifth, sixth, and seventh aspects of the invention, the rotation angle can be detected even if there is any part in the characteristic of the detection signal of the detection means. And a rotation angle detection device that can easily control the accuracy of the detection signal of the detection means.

According to the rotation angle detecting device according to the second aspect of the present invention, even if the characteristic of the detection signal of the detecting means has a small part, and if the characteristic of the detection signal of the detecting means has a certain part, the rotation angle can be detected. It is possible to realize a rotation angle detection device that can easily control the accuracy of the detection signal of the detection means at the time of manufacturing.

According to the rotation angle detecting device according to the third aspect of the invention, the characteristics of the detection signal of the detecting means have little droop, and even if there is a droop, the rotation angle can be detected. It is possible to realize a rotation angle detection device that can easily control the accuracy of the detection signal of the detection means.

According to the rotation angle detection device of the fourth invention, the detection sensitivity of the detection means is good, and the rotation angle can be detected even if there is any part in the characteristic of the detection signal of the detection means. It is possible to realize a rotation angle detection device that can easily control the accuracy of the detection signal of the detection means at the time of manufacturing.

According to the eighth, ninth, tenth, eleventh, and thirteenth inventions, the torque can be detected even if there is any part in the characteristic of the detection signal of the detection means. It is possible to realize a torque detection device that can easily control the accuracy of the detection signal of the means.

According to the torque detecting apparatus of the twelfth aspect, even in the event of a failure, if there is only one failed detecting means and the remaining detecting means can detect the torque, the torque detecting apparatus does not stop the torque detection. Can be realized.

In the torque detecting device according to the fourteenth aspect, the output of the magnetic sensor being selected, that is, the magnetic sensor used for calculating the current rotational torque, and the magnetic sensor that is not being selected, that is, the rotational torque, are output. The difference between the outputs of the magnetic sensors not used in the calculation is calculated, and the absolute value is compared, and the magnetic sensor that emits an effective output is selected based on the result of the positive / negative determination. The magnetic sensor that emits the output can be reliably selected without being affected by the change in the output characteristics and the fluctuation in the rotational speed, and the calculation of the rotational torque using the output of the selected magnetic sensor can be performed with high accuracy. It can be performed with high accuracy.

In the torque detecting device according to the fifteenth aspect, when the absolute value of the output difference of one of the selected magnetic sensors becomes smaller than the absolute value of the output difference of the other non-selected magnetic sensor, Since the selection of the magnetic sensor is switched on condition that the sign of the output difference is the same,
It is possible to reliably select a magnetic sensor that emits an effective output, and to calculate the rotational torque using the output of the selected magnetic sensor with high accuracy.

In the torque detecting device according to the sixteenth aspect, targets are juxtaposed on a first axis and a second axis which are coaxially connected via a torsion bar, and a magnetic sensor is disposed on each of the targets so as to face each other. The first axis and the second axis
The rotation torque applied to the axes causes a large difference in rotation angle between the two axes due to the torsion of the torsion bar, and the rotation torque applied to the first axis and the second axis can be reduced by selecting a magnetic sensor facing each target. It is possible to detect with high accuracy.

According to the steering device of the seventeenth aspect, torque can be detected even if there is any part in the output voltage characteristics of the magnetic sensor of the torque detection device. A steering device that can easily control the accuracy of the output voltage of the sensor can be realized.

In the steering apparatus according to the eighteenth aspect, the rotational torque of the steering shaft that connects the steered wheels and the steering mechanism is accurately detected by any one of the fourteenth to sixteenth aspects. From, various controls such as drive control of a steering assist motor performed based on this detection result,
The present invention has excellent effects, for example, it can be performed with high reliability.

[Brief description of the drawings]

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

FIG. 2 is a development view showing an outer peripheral surface of a target plate in a developed manner.

FIG. 3 is a flowchart showing operations of a rotation angle detection device and a torque detection device according to the present invention.

FIG. 4 is a flowchart showing the operation of the rotation angle detection device and the torque detection device according to the present invention.

FIG. 5 is a flowchart showing operations of the rotation angle detection device and the torque detection device according to the present invention.

FIG. 6 is a waveform diagram showing a detection signal of the MR sensor.

FIG. 7 is a flowchart showing an operation of the torque detection device according to the present invention.

FIG. 8 is a flowchart showing the operation of the torque detection device according to the present invention.

FIG. 9 is a flowchart showing the operation of the torque detection device according to the present invention.

FIG. 10 is a waveform chart showing a detection signal of the MR sensor.

FIG. 11 is a waveform chart showing a detection signal of the MR sensor.

FIG. 12 is a flowchart showing an operation of the torque detection device according to the present invention.

FIG. 13 is a waveform diagram showing a detection signal of the MR sensor.

FIG. 14 is a waveform chart showing a detection signal of the MR sensor.

FIG. 15 is a schematic diagram schematically showing a configuration of an embodiment of a rotation angle detection device and a torque detection device according to the present invention.

FIG. 16 is a principle view showing a main configuration of a torque detecting device according to an embodiment of the present invention.

17 is a flowchart showing an operation of the torque detection device shown in FIG.

FIG. 18 is a flowchart showing an operation of the torque detection device shown in FIG.

19 is a flowchart showing the operation of the torque detection device shown in FIG.

20 is an explanatory diagram for explaining the operation of the torque detection device shown in FIG.

FIG. 21 is a flowchart showing the operation of the torque detection device according to the present invention.

FIG. 22 is a flowchart showing the operation of the torque detection device according to the present invention.

FIG. 23 is a flowchart showing the operation of the torque detection device according to the present invention.

FIG. 24 is a flowchart showing the operation of the torque detection device according to the present invention.

FIG. 25 is a flowchart showing the operation of the torque detection device according to the present invention.

FIG. 26 is a flowchart showing the operation of the torque detection device according to the present invention.

FIG. 27 is an explanatory diagram for explaining an operation of the torque detection device according to the present invention.

FIG. 28 is a principle view showing a main configuration of a torque detecting device according to an embodiment of the present invention.

FIG. 29 is a longitudinal sectional view showing a configuration of a steering device according to the present invention.

FIG. 30 is an explanatory diagram for explaining an operation of the torque detection device according to the present invention.

FIG. 31 is a schematic diagram showing a configuration of a torque detection device according to the present invention applied to a steering device of an automobile.

FIG. 32 is an explanatory diagram illustrating an example of a change mode of the output voltage of the magnetic sensor.

FIG. 33 is a flowchart showing the content of a selection operation of a magnetic sensor.

FIG. 34 is an explanatory diagram showing another example of a change mode of the output voltage of the magnetic sensor.

FIG. 35 is an explanatory diagram showing an example of a change state of output voltages of two magnetic sensors arranged in a circumferential direction of a target.

FIG. 36 is a principle view showing a configuration example of a main part of a conventional torque detecting device.

FIG. 37 is an explanatory diagram for explaining an operation of a conventional torque detection device.

FIG. 38 is an explanatory diagram of a problem in a conventional selection procedure.

[Explanation of symbols]

Reference Signs List 1 Steering wheel (steering wheel) 1A, 46a MR sensor (magnetoresistive element, first magnetic sensor, first detecting means) 1B, 46b MR sensor (magnetoresistive element, third magnetic sensor, second detecting means) 2A , 47a MR sensor (magnetoresistive element, second magnetic sensor, first detecting means) 2B, 47b MR sensor (magnetoresistive element, fourth magnetic sensor, second detecting means) 11, 11a, 11b Sensor box 12 target Plate (rotating body) 13 Steering shaft 14, 14a, 30, 30a Signal processing unit 14aa, 14ab, 14ba, 14bb, 30aa,
30ab, 30ba, 30bb Table (storage means) 15 Target 15a First inclined portion 15b Second inclined portion 16, 35 Input shaft 17, 38 Output shaft 18 Pinion 19, 36, 25 Connection shaft (torsion bar) 21 Upper shaft (input) Shaft) 22, 24, 43c, 43d Projection (projection, magnetically discontinuous portion) 23 Lower shaft (output shaft) 33 Upper shaft 43 Torque detecting device 43a, 43b Peripheral surface 44 Electric motor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01D 5/18 G01D 5/18 L 3D033 G01L 3/10 G01L 3/10 B 5/22 5/22 // B62D 113: 00 B62D 113: 00 119: 00 119: 00 (72) Inventor Kinchi Tokumoto 3-5-8 Minamisenba, Chuo-ku, Osaka-shi, Osaka F-term in Koyo Seiko Co., Ltd. 2F051 AA01 AB05 AC07 BA03 2F063 AA34 AA35 AA36 AA50 BA08 BC02 BD05 CA00 CA40 DA01 DB01 DB07 DD03 DD05 EA03 GA52 GA54 GA68 GA69 GA70 GA74 KA01 KA06 LA01 LA02 2F069 AA86 AA88 AA99 BB40 CC05 DD00 DD30 GG04 GG06 AGG03 GG52 H02 GG52 GG02H17 GG52 GG65 H07 DA03 DA15 DA62 EA01 EC22 GG01 3D033 CA16 CA17 CA21 CA28 CA29 DB05

Claims (18)

[Claims] A first detecting means for detecting a target provided on the rotating body and a part close to the target so that a detected part continuously changes as the rotating body rotates. Detecting means for detecting a portion close to the target so as to output a detection signal having a phase different from the detection signal output by the first detection means by a predetermined electrical angle;
A rotation angle detection device comprising: a detection unit, wherein the rotation angle detection unit detects a displacement angle of the rotating body in a rotation direction based on a part detected by each of the first detection unit and the second detection unit. 2. The method according to claim 1, wherein the target is provided with a first inclined portion inclined in one direction along a peripheral surface of the rotating body and a target inclined in another direction along the peripheral surface of the rotating body. A certain second
The rotation angle detecting device according to claim 1, further comprising an inclined portion. 3. The rotation according to claim 2, wherein the first inclined portion and the second inclined portion have a substantially line-symmetric relationship with respect to a straight line in the axial direction of the rotating body that passes through a connection point between the two inclined portions. Angle detector. 4. The rotation angle detecting device according to claim 1, wherein a plurality of the targets are provided continuously along a peripheral surface of the rotating body. 5. The rotation angle detection according to claim 1, wherein the target is magnetically discontinuous with respect to a peripheral portion, and the first detection means and the second detection means are magnetic sensors. apparatus. 6. The magnitude of a detection signal output by the first detection means and the second detection means at the time of previous sampling, respectively.
Determining means for determining the magnitude of a detection signal output by the first detection means and the second detection means at the time of the current sampling; a substantially intermediate value between a maximum value and a minimum value to be taken by the detection signal; A determination means for determining the magnitude of the detection signal output during the current sampling by the second detection means; and a determination whether the detection signals output from the first detection means and the second detection means during the current sampling are within a predetermined range. The rotation device according to any one of claims 1 to 5, further comprising: a determination unit configured to determine whether a rotation angle of the rotating body is changed in a rotation direction based on each determination result of the determination unit. Angle detector. 7. Based on each determination result of each of said determination means,
The apparatus further includes a selection unit that selects any one of the first detection unit and the second detection unit and any one of the first inclined unit and the second inclined unit to be detected by the detection unit,
In order to detect the displacement angle of the rotating body in the rotation direction based on the detection means and the inclined portion selected by the selection means at the time of the previous sampling, and the detection signals output by the detection means at the time of the previous sampling and the current sampling, respectively. 7. The rotation angle detecting device according to claim 6, wherein: 8. A first detecting means provided with the rotation angle detecting device according to any one of claims 1 to 7 on an input shaft and an output shaft connected by a connecting shaft, respectively. Alternatively, the torque detecting device is adapted to detect a torque applied to the input shaft based on a difference of a detection signal output by the second detecting means due to a twist generated in the connecting shaft. 9. A sign judging means for judging a sign of each of a difference between the detection signals outputted by the first detecting means and a sign of the difference of the detecting signals outputted by the second detecting means, respectively. A first comparing means for comparing the magnitudes of the detection signals respectively outputted by the first detecting means and the second detecting means on the input shaft side when the sign of each difference is determined to be the same; 9. The torque detecting device according to claim 8, wherein the torque applied to the input shaft is detected based on a comparison result of the means. 10. When the sign judging means judges that the sign of each difference is different, a substantially intermediate value between a maximum value and a minimum value to be taken by each of the detection signals, a first detecting means on the input shaft side, A second comparing means for comparing magnitudes of the detection signals outputted by the second detecting means with each other, wherein a torque applied to the input shaft is detected based on a comparison result of the second comparing means. 9. The torque detector according to 9. 11. A first determination unit for determining whether at least one of the detection signals respectively output by the first detection unit is outside a predetermined range, and at least one of the detection signals respectively output by the second detection unit. A second determining means for determining whether or not one of them is outside a predetermined range; an absolute value of a difference between detection signals respectively outputted by the first detecting means;
Third comparing means for comparing the absolute value of the difference between the detection signals outputted by the detecting means, wherein the comparison result of the second comparing means, the judgment result of the first judging means, and the second judging means 11. The torque detecting device according to claim 10, wherein the torque applied to the input shaft is detected based on a result of the determination by the third comparing means and a result of the comparison by the third comparing means. 12. An abnormality detecting means for detecting an abnormality of a detection signal outputted by each of the pair of the first detecting means and the pair of the second detecting means, and the abnormality detecting means detects one of the detected signals. Means for making the difference between the detection signals output by the respective detection means of the pair including the detection means which output an abnormal detection signal when detecting an abnormal detection signal;
9. When the number of times is one, the torque applied to the input shaft is detected without using the detection signal.
12. The torque detector according to any one of claims 11 to 11. 13. A detection signal output in accordance with a part respectively detected by the first detection means and the second detection means, and a detection signal which is set in advance and detected by the first detection means and the second detection means. Each of the storage means for storing the corresponding detection signal to be output in response to the detection signal output by the first detection means and the second detection means and the content stored by the storage means. Means for outputting each of the detection signals to be output, based on each of the detection signals output by the means, so that each of the detection signals indicates a portion detected by each of the first detection means and the second detection means. The torque detecting device according to claim 8, wherein the torque detecting device is provided. 14. A plurality of magnetic targets which are arranged side by side in the circumferential direction of the rotating shaft and which are each inclined at substantially equal angles with respect to the axial direction, are opposed to the outside of the targets with their phases shifted in the circumferential direction. And two sets of two magnetic sensors that emit an output that changes according to the passage of each target are separated from each other in the direction of the axis length of the rotating shaft, and one of the magnetic sensors selected in each set is provided. A torque detection device configured to calculate a rotation torque applied to the rotating shaft using an output difference, wherein an absolute value of an output difference of a selected magnetic sensor and an absolute value of an output difference of a non-selected magnetic sensor are calculated. Comparing means for comparing the output difference of the selected magnetic sensor and the output difference of the non-selected magnetic sensor; and a determination result based on the determination result of the determination means and the comparison result of the comparison means. To calculate the rotational torque And a selecting means for selecting a magnetic sensor to be used. 15. The comparison unit according to claim 11, wherein the determination unit determines that the result of the determination by the determination unit is the same for the selected magnetic sensor and the non-selected magnetic sensor. 15. The configuration according to claim 14, wherein the selection of the magnetic sensor is changed when the absolute value of the output difference of the selected magnetic sensor falls below the absolute value of the output difference of the non-selected magnetic sensor by more than a predetermined amount. Torque detector. 16. The rotating shaft is a connected body of a first shaft and a second shaft coaxially connected via a torsion bar, and the target is near a connecting portion of the first shaft and the second shaft. 16. The torque detecting device according to claim 14, wherein the torque detecting device is provided in each of the following. 17. An input shaft connected to a steered wheel, an electric motor for steering assistance driven and controlled based on a steering torque applied to the steered wheel, an output shaft interlocked with the electric motor, and a steering applied to the input shaft. A steering device, comprising: the torque detection device according to any one of claims 8 to 13, wherein the torque detection device detects a torque by a torsion angle generated in a connection shaft that connects the input shaft and the output shaft. 18. A steering device comprising the torque detecting device according to claim 14, wherein a steering shaft that connects a steered wheel and a steering mechanism is configured as the rotation shaft.