JP2010197297A - Torque detection device and electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect easily and precisely that an ECU (Electronic Control Unit) 20 is assembled with a torque sensor 3 having a different specification from a torque sensor 3 regarded as an object by the ECU 20. <P>SOLUTION: A peculiar offset value is set relative to each spring rate corresponding to the spring rate of a torsion bar 104 by an offset setting circuit 231b, and the offset value of a sub-torque signal Ts is adjusted by an offset adjusting circuit 231a corresponding to setting of the offset setting circuit 231b. A peculiar threshold is set relative to each spring rate by a threshold setting part 242b corresponding to the spring rate of the torsion bar 104 of the torque sensor 3 regarded as an object by the ECU 20, and an abnormality determination part 242a determines whether the spring rate agrees therewith based on whether a difference between the sum of a main torque signal Tm and a sub-torque signal Ts and the set threshold is within a tolerance or not. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a torque detection device and an electric power steering device that applies a steering assist force to a steering mechanism of a vehicle.

2. Description of the Related Art Conventionally, as a steering device, an electric power steering device that applies a steering assist force to a steering mechanism by driving an electric motor according to a torque by which a driver steers a steering wheel has been widespread.
This type of electric power steering apparatus includes an electric motor, an electric power steering ECU (electronic control unit) that controls the electric motor, and a torque sensor that detects an input torque applied to the steering wheel.
The electric power steering ECU includes a left-hand drive type for left-hand drive vehicles and a right-hand drive type for right-hand drive vehicles. The electric power steering ECU of any specification has the same appearance, but the rotation direction of the electric motor is different, and if the specifications are confused when assembled to the vehicle, the steering operation cannot be performed.

For this reason, there has been proposed an electric power steering device that prevents erroneous mounting of an electric power steering ECU for a right-hand drive vehicle and a left-hand drive vehicle to the vehicle.
For example, in Patent Document 1, a test device equipped with an ID reading device is connected to an electric power steering ECU, and the vehicle specification identification ID on the vehicle side is obtained by the electric power steering ECU side through this test device. An electric power steering apparatus has been proposed in which an assembly error is detected by comparing the vehicle specification determined from the vehicle specification identification ID with the vehicle specification targeted by the electric power steering ECU. .

JP 2006-224722 A

By the way, the torque sensor has a coil configured to change impedance due to torsion of a torsion bar incorporated in the steering shaft, and is configured to output a detection signal corresponding to torsion of the torsion bar. The spring rate varies depending on the torsion bar.
Here, the electric power steering ECU adds to the steering wheel based on the input torque-sensor output voltage characteristic representing the relationship between the detection signal comprising the voltage signal of the torque sensor and the magnitude of the input torque applied to the torsion bar. The calculated input torque is calculated, and the steering assist amount is calculated based on the input torque.

  Therefore, if the spring rate of the torsion bar is different from the spring rate of the torsion bar of the torque sensor targeted by the electric power steering ECU, the input torque-sensor output voltage characteristics on the torque sensor side and the electric power steering ECU side Since the input torque-sensor output voltage characteristic is different, erroneous detection of the input torque occurs. Therefore, for example, as shown in FIG. 13, the assist current [A] is determined according to the magnitude of the input torque [Nm], and the actual driving current corresponding to the assist current is supplied to the electric motor. Since the assist current according to the input torque is not supplied to the electric motor, the steering assist force cannot be accurately generated.

For example, when an electric power steering ECU and a torque sensor having a higher spring rate than the torque sensor targeted by the electric power steering ECU are assembled, the output of the torque sensor becomes a smaller value, so the actual input torque On the other hand, the input torque recognized by the electric power steering ECU is calculated to be small. For this reason, the assist current tends to be insufficient, and the steering wheel becomes heavy.
Conversely, when the electric power steering ECU and a torque sensor having a lower spring rate than the torque sensor targeted by the electric power steering ECU are assembled, the output of the torque sensor becomes a larger value, so that the actual input The input torque recognized by the electric power steering ECU with respect to the torque is calculated to be larger. For this reason, there is a problem that the assist current tends to be excessive and the steering wheel becomes light.

  In order to avoid this, the conventional method for preventing erroneous assembly of the electric power steering ECU for the right-hand drive vehicle and the left-hand drive vehicle to the vehicle is applied, and the ID for identifying the torsion bar specification is provided on the vehicle side. The torsion bar specification identification ID is acquired on the electric power steering ECU side, and the spring rate of the torque sensor targeted by the electric power steering ECU coincides with the spring rate of the torque sensor assembled on the vehicle side. By determining whether to do so, it is possible to detect misassembly.

However, the torsion bar specification identification ID is not necessarily provided on the vehicle side. Therefore, when the torsion bar specification identification ID is not provided due to the circumstances of the vehicle manufacturer or the like, or even if the torsion bar specification identification ID is provided, the steering column and the electric power steering ECU are integrated. When the torsion bar specification identification ID cannot be acquired on the electric power steering ECU side, such as in the case of the integrated type, the erroneous mounting cannot be detected on the electric power steering ECU side. It is not possible to generate an appropriate steering assist force.
Accordingly, the present invention has been made paying attention to the above-mentioned conventional unsolved problems, and a torque sensor that can be used by a torque sensor specification and a calculation means for calculating an input torque from the output signal of the torque sensor. It is an object of the present invention to provide a torque detection device capable of accurately detecting whether or not the specifications match, and an electric power steering device using the torque detection device.

  According to a first aspect of the present invention, there is provided a torque detection apparatus comprising: torque detection means for outputting a torque signal corresponding to input torque; and calculation means for calculating the input torque based on the torque signal. The torque detection means has notification means for notifying preset specification information for specifying the specification of the torque detection means, and the calculation means is based on the specification information notified by the notification means, It is characterized by comprising determination means for determining whether or not the actual specification of the torque detection means matches the preset specification of the torque detection means that can be handled by the calculation means.

Further, in the torque detection device according to claim 2, the notification unit processes the torque signal according to the specification information, and the determination unit specifies the specification of the torque detection unit from the processed torque signal. It is characterized by doing.
According to a third aspect of the present invention, there is provided the torque detector according to the third aspect, wherein the torque signal is two torque signals having opposite characteristics, and the notification means uses at least one of the torque signal offset values as the specification information. The offset value is adjusted to a corresponding value, and the determination unit specifies the specification of the torque detection unit based on a range that the sum of the two torque signals can take.

Furthermore, the torque detection device according to claim 4 is provided with a communication unit for communication of the specification information between the notification unit and the calculation unit, and the notification unit transmits the specification information via the communication unit. The determination means specifies the specification of the torque detection means based on the specification information notified via the communication means.
Furthermore, in the torque detection device according to claim 5, the notification means outputs a torque signal according to the specification information in the torque detection means instead of a torque signal according to the input torque at a preset timing. The determining means specifies the specification of the torque detecting means based on the signal value of the torque signal at the timing.

According to a sixth aspect of the present invention, there is provided an electric power steering device based on a torque detection device that detects an input torque input to a steering mechanism using a torsion bar, and an input torque detected by the torque detection device. An electric power steering apparatus comprising a steering assist control means for generating a steering assist force in the steering mechanism, wherein the torque detector according to any one of claims 1 to 5 is used as the torque detector. It is characterized by that.
The electric power steering apparatus according to claim 7 is characterized in that the specification is a spring rate of the torsion bar.

According to the present invention, the specification information specifying the specification in the preset torque detection means is notified from the torque detection means side, and the specification in the torque detection means is determined on the calculation means side based on the notified specification information. Since it is determined whether or not the specifications of the target torque sensor are matched by the calculation means, it is possible to easily detect whether or not the specifications of the torque detection means and the calculation means match.
In particular, when applied as a torque detection device for an electric power steering device, when the torque detection means side and the control device for the electric power steering device incorporating the calculation means are separately assembled in the vehicle, for example, the spring rate of the torsion bar There is a possibility that parts with different specifications such as etc. may be mistakenly assembled. However, as described above, the specification mismatch between the torque detection means and the calculation means can be detected, so that it is possible to accurately detect an assembly error of the control device for the electric power steering apparatus.

According to the present invention, since the specification in the torque detection means is notified from the torque detection means side to the calculation means side, on the calculation means side, the specifications in the torque detection means and the specifications of the torque sensor targeted by the calculation means Can easily be determined.
In particular, when applied to a torque detection device for an electric power steering device, the torque detection means side and the electric power steering device control device side in which the calculation means are incorporated are separately assembled in the vehicle. However, since it is possible to easily detect a mismatch in specifications, it is possible to easily and accurately detect an assembly error.

It is a figure showing the schematic structure of the electric power steering device to which the present invention is applied. It is sectional drawing of the principal part of FIG. It is sectional drawing of a torque sensor. It is the rear view which looked at the torque sensor of FIG. 3 from the arrow X side. It is a block diagram which shows schematic structure of a torque detection circuit and ECU. It is an output characteristic figure showing a correspondence with input torque and sensor output voltage. It is a flowchart which shows an example of the process sequence of the abnormality determination process in 1st Embodiment. It is a block diagram which shows schematic structure of the torque detection circuit and ECU in 2nd Embodiment. It is a flowchart which shows an example of the process sequence of the determination process in 2nd Embodiment. It is a block diagram which shows schematic structure of the torque detection circuit and ECU in 3rd Embodiment. It is explanatory drawing with which it uses for operation | movement description of 3rd Embodiment. It is a flowchart which shows an example of the process sequence of the determination process in 3rd Embodiment. It is explanatory drawing with which it uses for operation | movement description when an assembly | attachment error arises.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, a first embodiment will be described.
FIG. 1 is a schematic configuration diagram showing an embodiment of an electric power steering apparatus of the present invention.
In the figure, reference numeral 1 denotes a steering wheel. A steering force applied to the steering wheel 1 from a driver is transmitted to the steering shaft 2. This steering shaft 2 has an input shaft 2 a and an output shaft 2 b, one end of the input shaft 2 a is connected to the steering wheel 1, and the other end is connected to one end of the output shaft 2 b via a torque sensor 3. .

The steering force transmitted to the output shaft 2 b is transmitted to the lower shaft 5 via the universal joint 4 and further transmitted to the pinion shaft 7 via the universal joint 6.
The steering force transmitted to the pinion shaft 7 is transmitted to the tie rod 9 via the steering gear 8 and steers steered wheels (not shown). Here, the steering gear 8 is configured as a rack and pinion mechanism having a pinion 8a connected to the pinion shaft 7 and a rack 8b meshing with the pinion 8a, and the rotational motion transmitted to the pinion 8a is linearly moved by the rack 8b. It has been converted to movement.

The output shaft 2b of the steering shaft 2 is connected to a reduction gear 10 that transmits a steering assist force to the output shaft 2b. The reduction gear 10 includes an electric motor 12 that generates a steering assist force for the steering system. The output shaft is connected.
The torque sensor 3 detects an input torque (that is, a steering torque) input to the steering shaft 2 and detects a magnetic change caused by twisting of the torsion bar in accordance with the input torque. Is output to an electric power steering ECU (hereinafter referred to as ECU) 20.

  The torque sensor 3 is configured such that the impedance changes due to torsion of the torsion bar, and outputs a main torque signal Tm and a sub-torque signal Ts with output characteristics that are opposite to each other as shown in FIG. ing. That is, the main torque signal Tm is a signal that increases as the actual steering torque increases in the right-turn direction, and is a signal that is substantially a linear function of the actual steering torque. The sub-torque signal Ts is a signal that decreases as it increases in the right-turn direction, and is a signal that is substantially a linear function of the actual steering torque. The main torque signal Tm and the sub torque signal Ts are set so that the absolute values of the slopes of the two straight lines are the same.

  Further, the ECU 20 inputs various information such as the vehicle speed V from the vehicle speed sensor 15, the main torque signal Tm from the torque sensor 3, the sub torque signal Ts, the motor current of the electric motor 12 detected by a current detection sensor (not shown), Based on these, the steering assist control process for generating the steering assist force according to the steering torque is executed to control the drive of the electric motor 12, and the abnormality determination process is executed based on the main torque signal Tm and the sub torque signal Ts. An assembly error between the torque sensor 3 and the ECU 20 is detected.

FIG. 2 is a cross-sectional view of main parts showing details of the main parts of FIG.
The steering shaft 2 is rotatably supported in the steering column 103, and an input shaft 105 and a substantially cylindrical output shaft 106 are connected via a torsion bar 104 on the base end side (left side in FIG. 2). Has been. The torsion bar 104 is inserted into the output shaft 106, one end thereof is press-fitted and fixed to the input shaft 105, and the other end is fixed to the output shaft 106 by a pin 107.

Further, the proximal end side of the steering column 103 is connected to a gear housing 110 composed of a housing main body 108 and a lid member 109, and a worm wheel 111 press-fitted and fixed to the outer periphery of the output shaft 106 in the gear housing 110. A reduction gear (worm reduction device) 10 including a worm 112 meshing with the worm wheel 111 is accommodated. The worm 112 of the reduction gear 10 is connected to a rotating shaft of an electric motor (not shown), and the rotation of the electric motor is transmitted to the output shaft 106 via the worm 112 and the worm wheel 111, whereby the steering shaft 2 is steered. Auxiliary power is applied.
Further, the torque sensor 3 is provided on the outer periphery of the spline groove 114 formed on the distal end side (right side in FIG. 2) of the output shaft 106.

3 is a cross-sectional view showing a torque sensor according to an embodiment of the present invention, and FIG. 4 is a rear view of the torque sensor of FIG.
In FIG. 3, the torque sensor 3 is a rotary non-contact torque sensor, and a base member 116 attached to a recess formed in the housing main body 108 of the gear housing 110 via a bolt or the like, and coils 117a and 117b. The rotated coil bobbins 118a and 118b, the annular coil yokes 119a and 119b that accommodate the coil bobbins 118a and 118b inside, and the coil yokes 119a and 119b are covered, and the coil yokes 119a and 119b are attached to the base member 116. A cylindrical yoke retainer 120 for supporting and fixing, a sensor board 121 for detecting a current generated in the coils 117a and 117b and outputting a signal, and a harness 122 for connecting the sensor board 121 and the ECU 20 are provided.

As shown in FIG. 4, a sensor substrate 121 is fixed to the base portion 116 via screws 123, 123, and a window 124 is provided at a part of the back surface of the base portion 116 on which the sensor substrate 121 is arranged. It has been. The window 124 is provided for inserting and removing a tool for operating a variable resistor provided on the sensor substrate 121, and thus, after the sensor substrate 121 is fixed to the base portion 116, the window 124 is provided. However, the sensor output voltage can be adjusted.
4 is a bolt hole through which a bolt for attaching the base portion 116 to the housing body 108 is inserted.

As shown in FIG. 3, a first terminal 127 connected to the coupling pins 126 a and 126 b of the coils 117 a and 117 b and a second terminal 128 connected to one end of the harness 122 are soldered to the sensor board 121. It is attached.
Note that reference numeral 134 in FIG. 3 covers the upper surface of the sensor substrate 121 fixed to the base member 116 and the first terminal 127 which is a connection portion between the sensor substrate 121 and the connecting pins 126a and 126b of the coils 117a and 117b. It is a cover member to do.
FIG. 5 is a block diagram showing the configuration of the torque detection circuit 200 mounted on the sensor board 121 and the ECU 20 of FIG. 1 connected to the torque detection circuit 200.

The torque detection circuit 200 detects a voltage signal corresponding to torsion of the torsion bar 104, a bridge circuit 210 including a main detection coil LN1 and a sub detection coil LN2, a main torque signal output unit 220, and a sub torque signal output unit 230. And comprising.
The bridge circuit 210 includes an oscillation unit 210a, a current amplification unit 210b, a main detection coil LN1, a sub detection coil LN2, and resistors R1 and R2.
The oscillator 210a receives the power of the reference voltage TV supplied from the ECU 20 side and outputs an alternating current having a predetermined frequency. The current amplifying unit 210b amplifies the alternating current output from the oscillating unit 210a, supplies this to the main detection coil LN1 via the resistor R1, and supplies it to the sub-detection coil LN2 via the resistor R2. In a state where torque does not act, the resistors R1 and R2 are adjusted so that the voltage appearing at both ends of the main detection coil LN1 and the sub detection coil LN2 becomes a predetermined voltage.

Then, by twisting the torsion bar 104, the inductance of the main detection coil LN1 increases and the inductance of the sub detection coil LN2 decreases, so that both ends of the main detection coil LN1 and the sub detection coil LN2 A voltage signal corresponding to the torsion amount of the torsion bar 104 can be obtained, and a voltage signal whose outputs are opposite to each other can be obtained.
The main torque signal output unit 220 includes a reference power source 221 and a main torque output circuit 222 including an amplifier. The reference power source 221 operates based on the reference voltage Vref supplied from the ECU 20 side, and outputs an offset voltage for adjusting the offset value of the main torque signal Tm to a predetermined value V0 set in advance. Is provided.

The main torque output circuit 222 operates by receiving the electric power of the reference voltage TV supplied from the ECU 20 side, and receives and amplifies torque signals appearing at both ends of the main detection coil LN1. Then, the neutral voltage of the torque signal obtained from both ends of the main detection coil LN1 is set based on the offset voltage output from the offset adjustment circuit 221a. And after adjusting an output waveform, it outputs to ECU20 side as the main torque signal Tm.
The sub torque signal output unit 230 includes a reference power source 231 and a sub torque output circuit 232 including an amplifier. The reference power source 231 operates based on the reference voltage Vref supplied from the ECU 20 side, and includes an offset adjustment circuit 231a and an offset setting circuit 231b.

The offset adjustment circuit 231a outputs an offset voltage for adjusting the offset value of the sub torque signal Ts to the offset value set by the offset setting circuit 231b.
The offset setting circuit 231b sets an offset voltage corresponding to the spring rate of the torsion bar 104.
For example, when the spring rate of the torsion bar 104 is Br1 (for example, 18 [kgf · cm / deg]), the offset voltage is “V0 + Tso [V]”, and the spring rate is Br2 (for example, 21 [kgf · cm / deg]). Is set to “V0 [V]” as the offset voltage, and “V0−Tso [V]” is set as the offset voltage when the spring rate is Br3 (for example, 25 [kgf · cm / deg]).

The sub torque output circuit 232 operates by receiving the power of the reference voltage TV supplied from the ECU 20 side, and amplifies the torque signal that appears at both ends of the sub detection coil LN2. Then, the neutral voltage of the torque signal is set based on the offset voltage output from the offset adjustment circuit 231a. And after adjusting an output waveform, it outputs to ECU20 side as subtorque signal Tm.
That is, the main torque signal output unit 220 adjusts the offset voltage of the torque signal according to the torsion amount of the torsion bar 104 to be V0, amplifies it, and outputs it as the main torque signal Tm. On the other hand, the sub-torque signal output unit 230 adjusts the offset voltage of the torque signal according to the torsion amount of the torsion bar 104 to be the offset voltage according to the spring rate of the torsion bar 104 set by the offset setting circuit 231b. This is amplified and output as a sub torque signal Ts.

Note that Tso is set to a value (Tso> Vs) larger than a threshold component Vs described later. In this way, by setting the offset voltage component Tso so that Tso> Vs is satisfied, an error is caused by adjusting the offset voltage of the sub torque signal Ts in the abnormality determination in the abnormality determination unit 242a described later. It avoids being judged.
FIG. 6 shows the output characteristics of the torque sensor 3 when the spring rate of the torsion bar 104 is different.
When the spring rate is Br2, the offset voltage is V0 (for example, 2.5 [V]). Further, the main torque signal Tm and the sub torque signal Ts are set to have opposite characteristics. Therefore, as shown in FIG. 6, the main torque signal Tm and the sub torque signal Ts intersect at a point corresponding to the origin torque “0”, and the output voltage at that time is the offset voltage V0.

  On the other hand, when the spring rate is Br1 smaller than the spring rate Br2, the main torque signal Tm passes through the offset voltage V0, but has an output characteristic having a larger slope than that in the case of the spring rate Br2. When the spring rate is Br1, the offset voltage of the sub torque signal Ts is “V0 + Tso”. For this reason, the sub torque signal Ts has a larger output characteristic than the case where the spring rate is Br2, and also has a value higher by the offset voltage component Tso.

  On the other hand, when the spring rate is Br3 higher than the spring rate Br2, the main torque signal Tm passes through the offset voltage V0, but has an output characteristic with a smaller slope than the output characteristic in the case of the spring rate Br2. When the spring rate is Br3, the offset voltage of the sub torque signal Ts is “V0−Tso”. For this reason, the sub torque signal Ts has an output characteristic whose slope is smaller than that in the case of the spring rate Br2, and further has a value lower by the offset voltage component Tso.

  Returning to FIG. 5, the ECU 20 includes an arithmetic processing unit (CPU) 240, a main torque signal input interface unit 251 that performs input processing of the main torque signal Tm from the torque sensor 3, and sub torque that performs input processing of the sub torque signal Ts. A signal input interface unit 252, a control main torque amplifier 253 that amplifies the main torque signal Tm input via the main torque signal input interface unit 251, a reference power output circuit unit 254, and a torque sensor in the torque detection circuit 200 And a sensor power output circuit unit 255 for supplying a reference voltage TV. Although not shown, the ECU 20 includes a vehicle speed sensor 15, an interface unit for inputting various information such as a motor current, a drive circuit for driving and controlling the electric motor 12, and the like.

The arithmetic processing device 240 includes a control unit 241 and a torque abnormality detection unit 242.
The control unit 241 executes a steering assist control process based on the main torque signal Tm, the vehicle speed V, the motor current, and the like amplified by the control main torque amplifier 253, and generates a steering assist force according to the main torque signal Tm. The electric motor 12 is drive-controlled so that it is generated.
The torque abnormality detection unit 242 includes an abnormality determination unit 242a and a threshold setting unit 242b. The abnormality determination unit 242a is based on the main torque signal Tm and the sub torque signal Ts and the abnormality determination threshold value set by the threshold value setting unit 242b. It is determined whether or not the specifications of the sensor 3 match.

  The threshold value setting unit 242b sets a threshold value according to the specification of the torque sensor 3 targeted by the ECU 20. That is, when the spring rate of the torsion bar 104 of the torque sensor 3 is Br1, “TH1 ± Vs” is set as the threshold value. When the spring rate is Br2, “TH2 ± Vs” is set as the threshold value. When the spring rate is Br3, “TH3 ± Vs” is set as the threshold value.

  These threshold components TH1 to TH3 are set to the sum of the offset voltage of the main torque signal and the offset voltage of the sub torque signal corresponding to the specification of the torque sensor 3 which is the target in the ECU 20. That is, when the spring rate is Br1, since the offset voltage of the main torque signal is “V0” and the offset voltage of the sub torque signal is “V0 + Tso”, the sum “2 × V0 + Tso” is TH1. Similarly, when the spring rate is Br2, since the offset voltage of the sub torque signal is “V0”, “2 × V0” is set to TH2. When the spring rate is Br3, since the offset voltage of the sub torque signal is “V0−Tso”, “2 × V0−Tso” is TH3.

Further, as described above, the threshold component Vs is set to a value (Tso> Vs) smaller than the offset voltage component Tso.
The gain of the control main torque amplifier 253 is set to a value corresponding to the specification of the torque sensor 3 targeted by the ECU 20. That is, when the specification of the spring rate of the torque sensor 3 is Br1, the gain G1 is set. Further, when the spring rate is Br2, the gain G2 is set, and when the spring rate is Br3, the gain G3 is set.

  These gains G1 to G3 are set so that the amplification values by the control main torque amplifier 253 when the input torque to the torsion bar 104 is the same are the same regardless of the specifications of the torque sensor 3. . For example, when the spring rate is Br1, when the spring rate of the torsion bar 104 is Br1, the control main torque amplifier 253 is amplified by the control main torque amplifier 253 (gain G2). The gain G1 is set so that the amplified value Tm1 becomes the same value as the amplified value Tm2. Further, when the spring rate of the torsion bar 104 is Br3, the gain G3 is set so that the amplified value Tm3 by the control main torque amplifier 253 becomes the same value as the amplified value Tm2.

That is, as shown in FIG. 6, the main torque signal Tm has different output characteristics depending on the spring rate, and the output voltage is different even if the input torque is the same. For this reason, the gains G1 to G3 are set so that the magnitude of the input torque corresponds to the main torque signal Tm input to the control unit 241 on a one-to-one basis.
The reference power supply output circuit unit 254 is composed of, for example, a circuit with a fixed voltage division ratio in which two resistors are connected in series. By supplying a voltage at a connection point between the resistors, a constant reference voltage Vref is supplied to the torque sensor 3. The power is supplied to the reference power sources 221 and 231.

Next, a processing procedure of abnormality determination processing in the abnormality determination unit 242a will be described with reference to FIG.
This abnormality determination process is executed, for example, when the torque sensor 3 and the ECU 20 are assembled.
The abnormality determination unit 242a of the ECU 20 reads the main torque signal Tm from the main torque signal input interface unit 251 and the sub torque signal Ts from the sub torque signal input interface unit 252 and adds them (step S1).
Subsequently, abnormality determination is performed based on the sum of the main torque signal Tm and the sub torque signal Ts and the threshold set by the threshold setting unit 242b (step S2).
That is, the sum “Tm + Ts” of the main torque signal Tm and the sub torque signal Ts is expressed by the following equation:

It is determined whether or not the determination condition (1) is satisfied.
Tm + Ts <THn−Vs or Tm + Ts> THn + Vs (1)
Note that THn in the expression is THn = TH2, TH3 ± Vs when the threshold set by the threshold setting unit 242b is TH1 ± Vs, and THn = TH1, TH2 ± Vs. In this case, THn = TH3.
When the expression (1) is not satisfied, the assembly of the torque sensor 3 and the ECU 20 is the same, and the specification of the torque sensor 3 installed and the specification of the torque sensor 3 targeted by the ECU 20 are the same. Then, it is determined (steps S3 and S4). Then, the determination result is notified, for example, by displaying that it matches a determination result notification device such as a display device (not shown).

On the other hand, when the expression (1) is satisfied (step S3), the assembly of the torque sensor 3 and the ECU 20 is inconsistent, and the specifications of the torque sensor 3 targeted by the ECU 20 and the torque sensor 3 installed It is determined that the specifications are different (step S5). Then, the fact that there is a discrepancy is displayed on a determination result notification device such as a display device (not shown) to notify that the assembly is incorrect.
Therefore, for example, when the torque sensor 3 with the spring rate of the torsion bar 104 of Br2 and the ECU 20 for the torque sensor 3 with the spring rate of the torsion bar 104 of Br1 are assembled, as shown in FIG. 6, the spring rate Br2 In this case, since the offset voltage of the sub torque signal is V0, the sum of the main torque signal Tm and the sub torque signal Ts output from the torque sensor 3 is “2 × V0”.

On the other hand, since the ECU 20 targets the torque sensor 3 having a spring rate of Br1, “TH1 ± Vs” is set as the threshold value in the threshold value setting unit 242b. Since TH1 is “2 × V0 + Tso”, the determination condition is the following equation (2) from the above equation (1).
Tm + Ts <2 × V0 + Tso−Vs, or
Tm + Ts> 2 × V0 + Tso + Vs (2)
In this case, Tm + Ts is “2 × Vo”, Tso> Vs, and Tm + Ts <2 × V0 + Tso−Vs is satisfied. Therefore, it is determined that the assembly does not match, and a notification that the assembly is mismatched is notified. For this reason, the operator can recognize that it is an assembly error.

For example, when the torque sensor 3 having a spring rate of Br2 and the ECU 20 for the torque sensor 3 having a spring rate of Br3 are assembled, the ECU 20 has “TH3 ± Vs” set as a threshold value. , TH3 is “2 × V0−Tso”, and therefore the determination condition is the following equation (3) from the above equation (1).
Tm + Ts <2 × V0−Tso−Vs, or
Tm + Ts> 2 × V0−Tso + Vs (3)
In this case, Tm + Ts is “2 × V0”, Tso> Vs, and Tm + Ts> 2 × V0−Tso + Vs is satisfied. Therefore, it is determined that the assembly does not match, and a notification that the assembly is mismatched is notified. For this reason, the operator can recognize that it is an assembly error.

For example, when the torque sensor 3 having a spring rate of Br1 and the ECU 20 that targets the torque sensor 3 having a spring rate of Br1, Tm + Ts is “2 × V0 + Tso, and the spring rate is Br1. Since neither of the determination conditions Tm + Ts <2 × V0 + Tso−Vs and Tm + Ts> 2 × V0 + Tso + Vs are satisfied, it is determined that these assemblings match.
For example, when the torque sensor 3 having a spring rate of Br1 and the ECU 20 for the torque sensor 3 having a spring rate of Br3 are assembled, Tm + Ts is “2 × V0 + Tso, and the spring rate is Br3. Since the determination condition Tm + Ts> 2 × V0−Tso + Vs is satisfied, it is determined that these are assembly mismatches.

  Thus, the offset voltage of the main torque signal Tm is constant regardless of the specification of the torsion bar 104, the offset voltage of the sub torque signal Ts is adjusted to a different offset voltage for each specification of the torsion bar 104, and is applied on the ECU 20 side. The range that can be taken by the sum of the main torque signal Tm and the sub torque signal Ts obtained from the torque sensor 3 is compared with the sum of the main torque signal Tm and the sub torque signal Ts actually obtained from the torque sensor 3. In addition, it is possible to easily and accurately detect an assembly error between the torque sensor 3 and the ECU 20.

Further, an abnormality can be determined by setting an offset voltage by the offset setting circuit 231b on the torque detection circuit 200 side and setting a threshold value by the threshold setting 242b on the ECU 20 side. Therefore, even after the torque sensor 3 and the ECU 20 are assembled, or even when the torque sensor 3 and the ECU 20 are formed in an integrated column-ECU type, an assembly error can be detected easily and accurately.
If the assembly of the torque sensor 3 and the ECU 20 is the same, the main torque signal Tm and the sub torque signal Ts do not satisfy the above equation (1). However, it is possible to detect an abnormality in the torque sensor 3 by determining whether or not the expression (1) is satisfied.

In the first embodiment, the control main torque amplifier 253 adjusts the gain according to the specifications of the torque sensor 3 targeted by the ECU 20, thereby performing the steering assist control process in the control unit 241. However, the present invention is not limited to this, and the gain of the control main torque amplifier 253 is fixed, and steering by the control unit 241 is performed. In the auxiliary control process, a process according to the specification of the torque sensor 3 targeted by the ECU 20 may be executed.
Similarly, in the threshold value setting unit 242b, an abnormality determination is performed regardless of the specification of the torque sensor 3 by adopting a configuration in which the threshold value can be set according to the specification of the torque sensor 3 targeted by the ECU 20. However, the present invention is not limited to this. You may comprise so that the threshold value corresponding to the specification of the torque sensor 3 made into object by ECU20 may be fixed and set.

  Further, as described above, the gain of the control main torque amplifier 253 and the threshold value of the threshold value setting unit 242b can be set according to the specifications of the torque sensor 3 targeted by the ECU 20, for example, The specification of the torque sensor 3 is determined from the range that the main torque signal Tm and the sub torque signal Ts can take, and the gain of the control main torque amplifier 253 and the threshold value of the threshold setting unit 242b suitable for the specification corresponding thereto. , The specification on the ECU 20 side may be set in accordance with the specification of the assembled torque sensor 3.

  In the first embodiment, the case where the offset voltage of the sub torque signal is adjusted has been described. However, the present invention is not limited to this. By adjusting both or any one of the main torque signal and the sub torque signal, a signal obtained from both or either of the main torque signal and the sub torque signal becomes a unique value for each specification of the torque sensor 3. Whether or not the assembly is matched by comparing the specific signal value according to the specification of the torque sensor 3 as a target on the ECU 20 side with the signal value actually obtained from the torque sensor 3. You may make it judge.

  In the first embodiment, the torque signal obtained from the main detection coil LN1 is offset-adjusted and the amplified signal is used as the main torque signal Tm, the torque signal obtained from the sub-detection coil LN2 is offset-adjusted, and Although the case where the amplified signal is applied to the torque sensor that outputs the main torque signal Tm and the sub torque signal Ts to the ECU 20 side as the sub torque signal Ts has been described, the present invention is not limited to this. For example, the present invention can be applied even to a torque sensor configured to calculate a difference value between both ends of the main detection coil LN1 and the sub detection coil LN2 and output the difference value to the ECU 20 in two systems. In this case, one system is the main, the difference value between the voltages at both ends of both detection coils is the offset adjusted and amplified signal is the main torque signal Tm, the other system is the sub, and the voltage at both ends of both detection coils is A signal obtained by inverting and amplifying the difference value and adjusting the offset is defined as a sub torque signal Ts. And the offset voltage of a difference value should just be set similarly to the above according to the specification of a torque sensor.

Next, a second embodiment of the present invention will be described.
Since the second embodiment is the same as the first embodiment except that the configurations of the torque detection circuit 200 and the ECU 20 are different, the same parts are denoted by the same reference numerals, and detailed description thereof will be given. Is omitted.
FIG. 8 is a block diagram showing configurations of the torque detection circuit 200 and the ECU 20 in the second embodiment.
As shown in FIG. 8, the torque detection circuit 200 according to the second embodiment includes a torsion bar specification selector 301 in the torque detection circuit 200 according to the first embodiment shown in FIG. The sub torque signal output unit 230 includes a reference power source 231 and a sub torque output circuit 232, and the reference power source 231 includes an offset adjustment circuit 231a.

The offset adjustment circuit 231a adjusts the offset value of the voltage signal, which is the sub torque signal, of the main torque signal output unit 220 to a predetermined value V0 in the same manner as the offset adjustment circuit 221a.
The torsion bar specification selector 301 sets unique information for specifying the specification of the torsion bar 104 as a 2-bit selector signal. The torsion bar specification selector 301 is connected to the CPU 240 via communication lines L1 and L2.

  For example, as shown in FIG. 8, the torsion bar specification selector 301 is configured by connecting two arms composed of two switches SW1 and SW2 connected in series, and opening and closing each of the arms A1 and A2. The voltage at the connection point between the instruments is output as a selector signal. When the output of the arm A1 corresponds to the first bit signal TB0, the output of the arm A2 corresponds to the second bit signal TB1, and the two switches SW1 and SW2 connected in series are both conductive. 2-bit information is output by outputting a selector signal that is at a HIGH level (for example, 5 [V]) when the LOW level (for example, the GND voltage), the switch SW1 is in a conductive state, and the switch SW2 is in a cut-off state. It is configured to be possible. The switches SW1 and SW2 are configured to be able to hold the setting state until a setting change operation is performed.

  The values of the selector signals TB0 and TB1 and the specification of the torsion bar 104 are set to correspond one-to-one. For example, as shown in Table 1, both TB0 and TB1 are “0” (LOW level). When specification A, TB0 is “0”, when TB1 is “1” (HIGH level), specification B, when TB0 is “1”, when TB1 is “0”, when specifications C, TB0, and TB1 are both “1” , As specification D.

On the other hand, the ECU 20 in the second embodiment includes an arithmetic processing unit (CPU) 240, a main torque signal input interface unit 251 that performs input processing of the main torque signal Tm from the torque sensor 3, and input processing of the sub torque signal Ts. A sub-torque signal input interface unit 252, a reference power output circuit unit 254, and a sensor power output circuit unit 255 that supplies a torque sensor reference voltage TV to the torque detection circuit 200. Also in this case, an interface unit for inputting various types of information (not shown) and a drive circuit for driving and controlling the electric motor 12 are provided.
The arithmetic processing device 240 includes a control unit 241, a fail safe unit (F / S unit) 245, and a torsion bar specification determination unit 302.

  The control unit 241 inputs the main torque signal Tm via the main torque signal input interface unit 251. Then, the steering assist control process is executed based on the main torque signal Tm. The fail safe unit 245 inputs the main torque signal Tm via the main torque signal input interface unit 251 and also inputs the sub torque signal Ts via the sub torque signal input interface unit 252, and the main torque signal Tm and the sub torque signal Ts are input. First, abnormality detection of the torque sensor 3 is performed.

  The torsion bar specification determination unit 302 receives the selector signal from the torsion bar specification selector 301 transmitted via the communication lines L1 and L2, and specifies the specification of the torsion bar 104 of the torque sensor 3 based on these signals. . The torsion bar specification determination unit 302 holds the correspondence between the selector signal and the specification of the torsion bar 104 shown in Table 1 in advance, for example, and specifies the specification of the torsion bar 104 from the input selector signal. Then, it is determined whether or not the specified specification matches the preset specification of the torque sensor 3 targeted by the ECU 20, and if the specification does not match, a determination result of an unillustrated display device or the like is given as an assembly error. The notification device notifies that there is an assembly error, and when they match, the determination result is notified by the determination result notification device that the assembly is properly performed.

FIG. 9 is a flowchart illustrating an example of a processing procedure of determination processing executed by the torsion bar specification determination unit 302.
This determination process is executed, for example, when the torque sensor 3 and the ECU 20 are assembled.
Note that when the torque sensor 3 is assembled, the operator operates the torsion bar specification selector 301 to output a selector signal corresponding to the specification of the torsion bar 104 of the torque sensor 3, and switches SW1, SW2 of the arms A1, A2. SW2 conduction / non-conduction is set in advance.
When the determination process is executed, the ECU 20 first reads the selector signals TB0 and TB1 (step S11), and specifies the specifications of the torsion bar 104 of the torque sensor 3 based on the selector signals TB0 and TB1 and Table 1. (Step S12).

Next, the process proceeds to step S13, where it is determined whether or not the specifications of the torque sensor 3 that is held in advance by the ECU 20 and the specifications of the torque sensor 3 specified in step S12 match. When this is done, it is determined that the assembly is properly performed, and this is notified by the determination result notification device (step S14).
On the other hand, if they do not match in step S13, it is determined that there is an assembly error, and this is notified by the determination result notification device (step S15).
In this way, the torque sensor 3 is configured to notify the ECU 20 side of the selector signal that specifies the specification of the torsion bar 104, and the ECU 20 side specifies the specification of the torsion bar 104 of the torque sensor 3 based on the selector signal. And the specification of the torque sensor 3 targeted by the ECU 20 are used to determine whether or not the assembly is performed accurately, so that an assembly error can be easily detected.

  Further, by setting the torsion bar specification selector 301 on the torque detection circuit 200 side, a selector signal is output from the torque sensor 3 side, and abnormality determination can be performed. Therefore, even after the torque sensor 3 and the ECU 20 are assembled, or even when the torque sensor 3 and the ECU 20 are formed in an integrated column-ECU type, an assembly error can be detected easily and accurately.

In the second embodiment, the case where the torsion bar specification selector 301 is configured by the switches SW1 and SW2 connected in series so that 2-bit information can be output as a selector signal will be described. However, the present invention is not limited to this, and it may be configured to output only a selector signal specifying one specification, and the torsion bar specification selector 301 can be realized with a simpler configuration.
Further, the selector signal is not limited to 2 bits, and a selector signal having a number of bits corresponding to the type of specification can be output.

Next, a third embodiment of the present invention will be described.
Since the third embodiment is the same as the second embodiment except that the configurations of the torque detection circuit 200 and the ECU 20 are different, the same reference numerals are given to the same parts, and a detailed description thereof will be given. Is omitted.
FIG. 10 is a block diagram showing the configurations of the torque detection circuit 200 and the ECU 20 in the third embodiment.
As shown in FIG. 10, the torque detection circuit 200 in the third embodiment is provided with a torsion bar information output control unit 401 instead of the torsion bar specification selector 301 in the second embodiment. The arithmetic processing unit 240 of the ECU 20 includes a control unit 241, a fail safe unit (F / S unit) 245, and a torsion bar specification determination unit 402.

The torsion bar information output control unit 401 stores therein specific specification information corresponding to the specification of the torsion bar 104 of the torque sensor 3. Then, as shown in FIG. 11, with the rise of the sensor power supply TV supplied from the sensor power supply output circuit unit 255 as a trigger, a preset initialization period after the rise, for example, after the sensor power supply TV rises, the main torque output The circuit 222 and the sub-torque output circuit 232 are replaced with the voltage signal from the bridge circuit 210 during a predetermined period of several ms to several tens of ms from the time when the main torque signal Tm and the sub-torque signal Ts can be output. A predetermined voltage signal corresponding to the information is input to the main torque output circuit 222 and the sub torque output circuit 232. Thus, a constant voltage signal, that is, a voltage signal corresponding to the specification information is output as the main torque signal and the sub torque signal.
For example, as shown in FIG. 11A, when the specification of the torsion bar 104 is “A”, the main torque signal Tm is output as 2.5 [V] and the sub torque signal Ts is output as 0 [V]. . As shown in FIG. 11B, when the specification is “B”, the main torque signal Tm is output as 5 [V] and the sub torque signal Ts is output as 0 [V].

  The torsion bar specification determination unit 402 uses the rise of the sensor power supply TV output from the sensor power supply output circuit unit 255 as a trigger to trigger the main torque signal Tm and the sub torque signal Ts during the period corresponding to the initialization period on the torque sensor 3 side. , That is, specification information is detected. The torsion of the torque sensor 3 is based on the correspondence information indicating the correspondence between the specification information and the specification of the torsion bar 104 and the specification information detected from the voltage values of the main torque signal Tm and the sub torque signal Ts. The specification of the bar 104 is specified. Then, the specification of the torque sensor 3 targeted by the ECU 20 is compared with the specification of the torque sensor 3 specified from the specification information. If these do not match, an assembly error is detected by a determination result notification device such as a display device (not shown). When it is in agreement and matches, the determination result is notified by the determination result notifying device that the assembling has been properly performed.

FIG. 12 is a flowchart illustrating an example of a processing procedure of determination processing executed by the torsion bar specification determination unit 402.
This determination process is executed when the electric power steering apparatus is started up.
The torsion bar specification determination unit 402 starts determination processing triggered by the rise of the sensor power supply TV output from the sensor power supply output circuit unit 255, and when the initial period set in advance is reached, the main torque signal Tm and the sub torque signal Ts. Is read (steps S21 and S22).

Then, the specification of the torsion bar 104 of the torque sensor 3 is specified based on the main torque signal Tm and the sub torque signal Ts (step S23).
Here, the torsion bar information output control unit 401 supplies a constant voltage signal to the main torque output circuit 222 and the sub torque output circuit 232 as specification information during the initial period as shown in FIG. The input main torque signal Tm and sub torque signal Ts are signals corresponding to the specification information.

  Therefore, when the voltage value of the main torque signal Tm is “2.5 [V]” and the voltage value of the sub torque signal Ts is “0 [V]”, the torsion bar 104 is specified as the specification A. Then, the specification of the torque sensor 3 as a target in the ECU 20 is compared with the specification specified in step S23, and if they match, it is determined that the assembly has been performed accurately, and this is determined by the determination result notification device. Notification is made (steps S24 and S25).

On the other hand, when the specification specified in step S23 and the specification held in the ECU 20 do not match, it is determined as an assembly error, and this is notified by the determination result notification device (steps S24 and S25).
In this way, the torque sensor 3 is configured to notify the ECU 20 of specification information for specifying the specification of the torsion bar 104 of the torque sensor 3, and the ECU 20 side specifies the specification of the torque sensor 3 based on the specification information. By comparing the specification of the torque sensor 3 that is the target of the ECU 20 to determine whether or not the assembly is performed accurately, it is possible to easily detect an assembly error.

In addition, since the specification information is output from the torque sensor 3 side by the torsion bar information output control unit 401, the torque sensor 3 and the ECU 20 may be assembled or may be formed as a column-ECU integrated type. However, it is possible to easily and accurately detect an assembly error.
In the third embodiment, the case where the specification information is transmitted using both the main torque signal Tm and the sub torque signal Ts has been described. However, the present invention is not limited to this, and only one of the signals is transmitted. If the initialization period is relatively long, it is possible to handle more specifications by switching the voltage value of one signal, for example, the main torque signal Tm, to multiple levels. It is also possible to configure such that the specified specification information can be transmitted.

Further, in the second and third embodiments, since the specification of the torque sensor 3 can be recognized on the ECU 20 side, on the ECU 20 side, the torque sensor 3 with respect to the torque sensor 3 is determined according to the specification of the torque sensor 3. The specification may be changed and set.
In the second and third embodiments, the torque signal from the main detection coil LN1 is offset adjusted and the amplified signal is used as the main torque signal Tm, and the torque signal from the sub detection coil LN2 is offset adjusted. Further, although the case where the amplified signal is applied to a torque sensor that outputs the main torque signal Tm and the sub torque signal Ts to the ECU 20 side as the sub torque signal Ts has been described, the present invention is not limited to this. For example, the present invention can be applied even to a torque sensor configured to calculate a difference value between both ends of the main detection coil LN1 and the sub detection coil LN2 and output the difference value to the ECU 20 in two systems.

Here, the torque sensor 3 corresponds to the torque detection means, the ECU 20 corresponds to the calculation means, and the ECU 20 corresponds to the steering assist control means.
In the first embodiment, the offset adjustment circuit 231a and the offset setting circuit 231b correspond to a notification unit, and the abnormality determination unit 242a and the threshold setting unit 242b correspond to a determination unit.
In the second embodiment, the torsion bar specification selector 301 corresponds to the notification unit, the torsion bar specification determination unit 302 corresponds to the determination unit, and the communication lines L1 and L2 correspond to the communication unit.
In the third embodiment, the torsion bar information output control unit 401 corresponds to the notification unit, and the torsion bar specification determination unit 402 corresponds to the determination unit.

DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering shaft 3 Torque sensor 20 Electric power steering control unit (ECU)
104 Torsion bar 200 Torque detection circuit 210 Bridge circuit 221a Offset adjustment circuit 222 Main torque output circuit 231a Offset adjustment circuit 231b Offset setting circuit 232 Sub torque output circuit 242a Abnormality determination unit 242b Threshold setting unit 301 Torsion bar specification selector 302, 402 Torsion Bar specification determination unit 401 Torsion bar information output control unit

Claims (7)

Torque detecting means for outputting a torque signal corresponding to the input torque;
A torque detecting device comprising: a calculating means for calculating the input torque based on the torque signal;
The torque detection means has notification means for notifying preset specification information for specifying the specification of the torque detection means,
Based on the specification information notified by the notifying means, the calculating means matches an actual specification of the torque detecting means with a preset specification of the torque detecting means that can be handled by the calculating means. A torque detection apparatus comprising a determination means for determining whether or not. The notification means processes the torque signal according to the specification information,
The torque detection device according to claim 1, wherein the determination unit specifies a specification of the torque detection unit from the torque signal after processing. The torque signals are two torque signals having opposite characteristics,
The notifying means adjusts an offset value of at least one of the torque signals to an offset value according to the specification information;
The torque detection device according to claim 2, wherein the determination unit specifies a specification of the torque detection unit based on a range in which a sum of the two torque signals can be obtained. A communication means for communicating the specification information is provided between the notification means and the calculation means,
The notification means notifies the specification information via the communication means,
The torque detection device according to claim 2, wherein the determination unit specifies a specification of the torque detection unit based on the specification information notified through the communication unit. The notifying means outputs a torque signal corresponding to the specification information in the torque detecting means instead of a torque signal corresponding to the input torque at a preset timing,
The torque detection device according to claim 2, wherein the determination unit specifies a specification of the torque detection unit based on a signal value of the torque signal at the timing. A torque detection device for detecting an input torque input to the steering mechanism using a torsion bar;
In an electric power steering apparatus comprising: a steering assist control means for generating a steering assist force in the steering mechanism based on an input torque detected by the torque detector;
An electric power steering device using the torque detection device according to any one of claims 1 to 5 as the torque detection device.   The electric power steering apparatus according to claim 6, wherein the specification is a spring rate of the torsion bar.

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