JPH0769234B2 - Torque detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a torque detector for detecting torque in a power steering device of a vehicle or the like in a non-contact and digital amount.

[Conventional technology]

Generally, for example, when detecting torque applied to a steering shaft for a vehicle power steering device,
A torsion bar, which is an elastic member, is connected either in the middle of the steering shaft or in the steering system, and the rotation angle of the input shaft side end that is the steering wheel side of the torsion bar and the output shaft side end that is the opposite side. Is known, and the torsion angle of the torsion bar, and thus the torque, is detected from the difference in the rotation angles.

Further, as a method of detecting the torque in a non-contact manner, two discs having slit rows for detecting the rotation angles of both ends of the torque, and two sets of slit rows of each disc are detected. It is already known to use a light emitting element such as a light emitting diode and a photocoupler including a light receiving element such as a phototransistor.

In this case, the detection signal for detecting the torque as the difference between the rotation angles of the two disks may be an analog amount or a digital amount.
For example, one set of photocouplers is used for two slit disks that detect the rotation angles of both ends of the torsion bar, and when the torsion bar is twisted by the torque, the two circular slits are out of phase, The change in the amount of light passing through the slit is detected as an analog amount.

However, in this analog system, drift occurs due to aging of the electronic circuits and elements, dirt, etc., and sufficient reliability cannot be obtained as a torque detector for a vehicle power steering device. In order to be used to process the detected signal it has to be converted into a digital quantity.

On the other hand, as a method of detecting with a digital amount, the angle of rotation of the disc is determined as an absolute value by reading the angle in binary using a slit disc having a large number of slit rows in which the number of divisions is doubled. Increment that detects the rotation angle of the disk by counting the absolute method that is detected and whether the slit formed in the disk increases or decreases by one each in forward rotation or reverse rotation (or right rotation or left rotation). As a conventional torque detector based on the former absolute method, for example, the one disclosed in Japanese Utility Model Application Laid-Open No. 59-137540 is known.

[Problems to be solved by the invention]

However, in the above-described conventional torque detector by the increment method, it is difficult to set the torque zero point, and even if the torque zero point is set in advance and stored in the electronic circuit, if the counting circuit miscounts due to noise or the like, Since there is no correction method, the zero point goes crazy, and errors accumulate over time, resulting in poor reliability and difficulty in practical application.

Further, in the absolute type torque detector described in the above-mentioned prior art publication, since the relative rotation angle is directly measured, there is no miscount, but the pulse detected by the increment type is detected electrically. Since the frequency cannot be doubled, the number of slits in the maximum number of slit rows and the number of photo couplers increase. For example, assuming a general quadrupling in the increment method,
In the absolute method, the number of slits in the maximum number of slit rows must be set to four times that in the increment method. If the number of slits in the maximum number of slit rows is set to (2000/1 rotation), 11 rows of slits will be formed on the slit disk. There is a problem in that it is necessary to line up 11 pairs of photocouplers in a row, which makes them large and expensive and difficult to put into practical use for vehicles.

The present invention has been made by paying attention to such a conventional problem, and it is possible to electrically double the frequency of a detection pulse.
The maximum number of slits and the number of photo couplers used are small,
Therefore, in the torque detector by the increment method that can be manufactured at a small size and at a low cost, the range of the zero torque of the preset minute torque width is clearly defined to make a mistake in counting the slits for detecting the rotation angle of the slit disk. It is an object of the present invention to provide a torque detector capable of correcting the count and also detecting a failure of the detector and improving reliability and safety essential for a vehicle. is there.

[Means for solving problems]

Therefore, according to the present invention, an elastic member is connected between the input shaft and the output shaft, and the input shaft side rotating body and the output shaft that rotate integrally with the input shaft side end and the output shaft side end of the elastic member, respectively. A side rotating body is provided, and the torque applied to the input shaft is detected from the difference between the rotation angle of the input shaft side rotating body detected by the first detecting means and the rotation angle of the output shaft side rotating body detected by the second detecting means. In the torque detector, third detecting means for detecting whether or not the torque applied to the input shaft is within a preset zero range is provided in association with the input shaft side rotating body and the output shaft side rotating body. It is characterized by.

[Action]

The rotation angle of the input shaft side rotating body that rotates together with the input shaft side end of the elastic member connected between the input shaft and the output shaft is counted by the first detecting means, and the output shaft side end of the elastic member is counted. The rotation angle of the output shaft side rotating body that rotates integrally with the unit is counted by the second detecting means, and the torque applied to the input shaft is detected as the difference between these rotation angles.

At this time, it is determined whether or not the torque applied to the input shaft is within a preset zero range by the third detecting means provided in association with the input shaft side rotating body and the output shaft side rotating body. Detected as a quantity signal.

Therefore, whether or not there is a miscount depends on whether the difference between the rotational angles of the two rotating bodies counted by the first and second detecting means is zero and whether the detection signal in the zero range by the third detecting means matches. Can be checked and corrected, and by monitoring the absolute value or frequency of correction or miscount, it is possible to detect the failure of the detector itself, which is indispensable for vehicle reliability and safety. improves.

〔Example〕

An embodiment of the present invention based on a light transmission system will be described below with reference to the drawings.

First, the configuration will be described.

In FIG. 1, the input shaft 1 is connected to a steering wheel side member (not shown) at the right end of the drawing, and the input shaft 1 has a through hole 1a formed in its axial center portion. The output shaft 2 is also connected to a steering gear side member (not shown) on the left side of the drawing, and a fitting hole 2a is formed in a portion of the output shaft 2 facing the input shaft 1. Then, the torsion bar 3 that is an elastic member is inserted into the through hole 1a of the input shaft 1, and the right end of the torsion bar 3 on the input shaft side in the drawing is rotated integrally with the right end of the input shaft 1 by the pin 4. The left end, which is the output shaft side end of the torsion bar 3, projects from the through hole 1a of the input shaft 1, and the projecting portion is fixed to the fitting hole 2a of the output shaft 2 by press fitting so as to rotate integrally. It

A small diameter portion 3a is formed in a portion slightly on the input shaft 1 side of the press-fitting portion of the torsion bar 3, and a bush 5 is fitted between the small diameter portion 3a and the inner diameter of the input shaft 1, whereby the small diameter portion of the torsion bar 3 is formed. The portion 3a and the left end of the input shaft 1 are relatively rotatably fitted.

Then, as shown in FIGS. 1 and 2, in the mounting portion of the bush 5, a protrusion 1b is formed at the end of the input shaft 1 and a recess 2b is formed at the end of the output shaft 2, and When the twisting angle of the torsion bar 3, that is, the relative rotational angle difference between the left end of the input shaft 1 and the right end of the output shaft 2 becomes a predetermined angle, the projection 1b of the input shaft 1 and the recess of the output shaft 2 are engaged. It comes into contact with 2b to prevent further relative rotation.

Further, the input shaft side disc 6 is fixed to the outer periphery of the left end of the input shaft 1, and the output shaft side disc 7 is fixed to the outer periphery of the right end of the output shaft 2, The output shaft side disk 7 has exactly the same shape and is shown in FIG.

In FIG. 3, the input shaft side disk 6 and the output shaft side disk 7 are the first slit rows 6a and 7a in which a large number of slits are formed on the same circumference at equal intervals, and the first slit rows 6a and 7a. Inside the slit rows 6a and 7a, there are second slit rows 6b and 7b in which a smaller number of slits than the first slit rows 6a and 7a are formed on the same circumference at equal intervals.

Returning to FIG. 1, an assembly in which the input shaft 1 and the output shaft 2 are connected by the torsion bar 3 and the input shaft side disk 6 and the output shaft side disk 7 are fixed as described above is a vehicle body not shown. The torque detector fixed to the side member is inserted from the opening (right side in the drawing) of the housing 8, and the output shaft 2 is rotatably supported by the bearing 9 with respect to the housing 8. Further, the cover 10 is fitted in the opening of the housing 8 so that the input shaft 1
Is rotatably supported by a bearing 11 with respect to the cover 10 and the housing 8, and a dust seal 12 is mounted between the input shaft 1 and the cover 10.

Further, the photocoupler first unit 13 is mounted so as to engage with the first slit rows 6a and 7a of the input shaft side disc 6 and the output shaft side disc 7 from a part of the housing 8 (the upper part of the drawing). Fixed to the housing 8 and the photocoupler first
The outside of the unit 13 is covered with a cover 14. Then, from a part (lower part in the figure) of the housing 8 on the side substantially opposite to the photocoupler first unit 13, the photocoupler second unit
15 is mounted so as to engage with the second slit rows 6b and 7b of the input shaft side disk 6 and the output shaft side disk 7, and the housing 8 is attached.
The outer side of the photocoupler second unit 15 is covered with a cover 16.

As shown in FIGS. 1, 4, and 5, the photocoupler first unit 13 includes a printed board 40 fixed to the housing 8 and a holder 17 adhered to the printed board 40.
And the first slit row 6a of the input shaft side disc 6 rotating along the groove 17a formed in the holder 17 and the first slit row 6a of the output shaft side disc 7 rotating along the groove 17b formed in the holder 17. It has auxiliary slit plates 18 and 19 fixed to the holder 17 along one slit row 7a. This auxiliary slit plate 18
And 19 have slit rows having the same pitch as the first slit rows 6a and 7a, and part of the first slit rows 6a and 7a of the input shaft side disc 6 and the output shaft side disc 7 are cut off. Equal to one. Further, the photocoupler first unit 13 includes a light emitting element 20 such as a light emitting diode and a lens portion which face each other with the first slit row 6a of the input shaft side disc 6 and the auxiliary slit plate 18 interposed therebetween.
21 and lens section 22 and light receiving element 23 such as a phototransistor
First photo coupler 24 consisting of, and this first photo coupler
In parallel with 24, the first slit row 6a of the disk 6 on the input shaft side is also provided.
And the light-emitting element 25, which faces the first slit array 6a with the auxiliary slit plate 18 interposed therebetween, but is offset from the first photo-coupler 24 so as to obtain a signal whose phase is shifted by 1/4 pitch. And a second photocoupler 29 including a lens portion 26, a lens portion 27, and a light receiving element 28, and a light receiving element 30 and a lens portion which face each other with the first slit row 7a of the output shaft side disk 7 and the auxiliary slit plate 19 interposed therebetween. 31 and lens section 32 and light receiving element
A third photocoupler 34 consisting of 33 and a first slit array of the output shaft side disk 7 in parallel with the third photocoupler 34.
7a and the auxiliary slit plate 19 are sandwiched between, but the third
The photocoupler 34 is composed of a light emitting element 35, a lens portion 36, a lens portion 37, and a light receiving element 38, which are arranged so as to be shifted with respect to the first slit array 7a so as to obtain a signal whose phase is shifted by 1/4 pitch. 4 photo coupler 39.

These light emitting element and light receiving element are plastic packaged including the formation of the lens portion and bonded to the holder 17, the holder 17 is bonded to the printed circuit board 40, and the lead wires of the light emitting element and the light receiving element are in a printed pattern. Connected. Further, an electronic circuit 41 including ICs, Cs, Rs, etc. is formed on the print pattern to perform signal processing for transmission such as signal waveform shaping and amplification.

As shown in FIGS. 1, 6, and 7, the photocoupler second unit 15 has a printed circuit board 52 fixed to the housing 8 and a holder 43 bonded to the printed circuit board 52. The input shaft-side disc 6 and the output shaft-side disc 7 rotate along the grooves 43a and 43b formed in 43. An optical path 44 is formed in the holder 43 between the second slit row 6b of the input shaft side disk 6 and the second slit row 7b of the output shaft side disk 7, and the optical path 44 and the input shaft side disk 6 are formed. A fifth photocoupler 49 including a light emitting element 45, a lens portion 46, a lens portion 47, and a light receiving element 48 is arranged outside the output shaft side disk 7.

The second slit row 6b of the input shaft side disk 6 and the second slit row 7b of the output shaft side disk 7 that face each other across the optical path 44 are in a state where the torsion bar 3 has no twist and the torque is zero. In order to obtain signals with the same phase, the input shaft side disk 6
And the output shaft side disk 7 are fixed to the input shaft 1 and the output shaft 2, respectively.

The width of the optical path 44 is equal to or more than one pitch of the second slit rows 6b and 7b, and the light from the light emitting element 45 allows the room 50 between the lens portion 46 and the output shaft side disk 7, the optical path 44, and When the light is received by the light receiving element 48 through the room 51 between the input shaft side disc 6 and the lens portion 47, the light path 44 and the rooms are diffused in the light path 44 and the rooms 50 and 51 to have a uniform distribution. The package including the wall surfaces of 50 and 51 and the lens portions 46 and 47 is assumed to scatter light as much as possible, and if necessary, between the light emitting element 45 and the disc 7 on the output shaft side, in the optical path 44, or on the input shaft side. A filter for scattering light is provided between the disk 6 and the light receiving element 48.

Similar to the photocoupler first unit 13 described above, these light emitting element and light receiving element are also plastic packaged including the formation of the lens portion and bonded to the holder 43, and the holder 43 is bonded to the printed board 52. The lead wires of the light emitting element and the light receiving element are connected to the printed pattern. Further, an electronic circuit 53 including ICs, Cs, Rs, etc. is formed on the printed pattern, and signal processing for transmission such as signal waveform shaping and amplification is performed.

Returning to FIG. 1, the electronic circuit 41 of the photocoupler first unit 13 and the electronic circuit 53 of the photocoupler second unit 15 are
It is connected to a further electronic circuit 55 and an EPS controller 56, which includes, for example, a microcomputer.

Next, the operation of the above embodiment will be described.

When a steering torque (not shown) is steered to input a steering torque, the input shaft 1 rotates, and the input shaft side disk 6 rotates with respect to the housing 8 fixed to the vehicle body side together with the rotation of the input shaft 1. The slits of the first slit row 6a of the disc 6 on the input shaft side are the photocoupler first unit 13
The light emitted from the light emitting element 20 of the first photocoupler 24 is passed or blocked, so that the light receiving element 23 converts the amount of light which changes depending on the presence or absence of the slit into an electric signal and outputs the electric signal. The electric signal is subjected to waveform shaping and amplification in the electronic circuit 41, and further sent to the external electronic circuit 55 and the EPS controller 56, where the first slit row 6a of the input shaft side disk 6 is counted by the increment method, The rotation angle of the input shaft side disk 6, that is, the input shaft side end of the torsion bar 3 is detected.

At this time, the light receiving elements 28 of the second photocoupler 29 arranged so as to be shifted so that a signal whose phase is shifted by 1/4 pitch from the first photocoupler 24 of the photocoupler first unit 13 can be obtained.
Similarly, the detection signal of
It is sent to the S controller 56 and the detection signal from the second photocoupler 29 is used to determine whether the input shaft side disk 6 is rotating left or right, that is, the steering wheel is steering left or steering right. While the steering direction is determined, the detection signal from the first photocoupler 24 is preferably quadrupled.

The rotation of the input shaft 1 due to the steering torque is transmitted to the output shaft 2 via the torsion bar 3 and the output shaft 2 rotates. As the input shaft 1 rotates, the output shaft side disk 7 rotates with respect to the housing 8. , The slit of the first slit row 7a of the disc 7 on the output shaft side is the third of the photocoupler first unit 13
The rotation angle of the output shaft side disk 7, that is, the output shaft side end of the torsion bar 3 is detected by counting by the light emitting element 30 and the light receiving element 33 of the photocoupler 34 in the increment method.

At this time, the light receiving element 38 of the fourth photocoupler 39 arranged so as to be shifted so that a signal whose phase is shifted by 1/4 pitch from the third photocoupler 34 of the photocoupler first unit 13 is obtained.
Similarly, the detection signal of is processed by the electronic circuit 41 and then EPS
The signal sent to the controller 56 is used to determine whether the output shaft side disk 7 is rotating right or left using the detection signal from the fourth photocoupler 39, and the detection signal from the third photocoupler 34 is preferably four times as large. Be lapped.

Since the auxiliary slit plates 18 and 19 have slits having the same pitch as the first slit row 6a of the input shaft side disc 6 and the first slit row 7a of the output shaft side disc 7, each photo coupler 24, 29, 34, 39 detect the light and darkness of the light passing through the plurality of slits. .

With the rotation of the input shaft 1, the torsion bar 3 and the output shaft 2 as described above, the steering torque is transmitted from the input shaft 1, the torsion bar 3 and the output shaft 2 to the tire through a steering gear and a link mechanism (not shown) and is transmitted to the tire. While steering the vehicle, reaction force torque is applied to the tire from the road surface, and this reaction force torque is transmitted to the output shaft 2 via the link mechanism and the steering gear. Therefore, the torsion bar 3 is twisted and the input shaft 1 is steered. The torque is balanced with the reaction torque of the output shaft 2. Therefore, the rotation angle of the input shaft side disc 6 and the rotation angle of the output shaft side disc 7 have a difference equal to the twist angle of the torsion bar 3.

The computer in the EPS controller 56 receives the pulse signal from the third slit 7a of the disc 7 on the output shaft side from the third photo coupler 34, and then the third photo coupler.
When a pulse signal is input from 34, it is determined whether the pulse signal is in the right rotation direction or the left rotation direction based on the detection signal of the fourth photocoupler 39, and the pulse signal between the two pulses of the output shaft side disk 7 is determined. The number of pulses of the pulse signal from the first slit array 6a of the disc 6 on the input shaft side from the first photocoupler 24 is input, and the pulse signal is rotated in the clockwise direction based on the detection signal of the second photocoupler 29. Or the left rotation direction. That is, while one pulse of the output shaft side pulse is input to either the right rotation or the left rotation, the number of pulses of the input shaft side pulse to the right rotation or the left rotation is counted, and the counting result Is stored in a predetermined storage area of a computer storage device, and the counting result, that is, the input shaft side disk 6 is stored.
The difference between the output shaft side disk 7 and the output shaft side disk 7 is taken as the torque value.

Then, the number of input axis side pulses input while one pulse of the output axis side pulse is input next is counted, and the counted number of pulses is added to the previously stored number of pulses. It should be judged whether it should be subtracted or should be subtracted from the rotation direction, and based on the judgment result, the counted pulse number is added or subtracted from the stored pulse number, and the calculation result is stored in the predetermined storage area. The stored count value is updated and stored instead of the previous count result, and the above operation is repeated every time the output axis side pulse is input. Therefore, the difference value of the rotation angle corresponding to the torque at that time is always stored in the predetermined storage area, and the torque value at that time can always be detected by reading this difference value and converting it to the torque value. .

Further, in such a steering process, that is, a torque detection process, when the torque is not acting on the torsion bar 3 at all or when the torque is acting very small, that is, the torque is within a preset zero range. At a certain time, the phase of the second slit row 6b of the input shaft side disk 6 and the second slit row 7b of the output shaft side disk 7 were in phase with each other and emitted from the light emitting element 45 of the photocoupler second unit 15. The light is received by the light receiving element 48, converted into an electric signal, shaped and amplified by the electronic circuit 53, and then sent to the electronic circuit 55 and the EPS controller 56.

The light emitted from the light emitting element 45 is emitted from the room 50 and the optical path 44.
Since the light is diffused in the room 51, the light receiving element 48 detects the average value of the light.

When the torque is larger than the zero range, the light emitting element
The light from 45 is blocked and does not reach the light receiving element 48. Further, when the torque reaches a preset maximum value, as shown in FIG. 2, the projection 1b of the input shaft 1 comes into contact with the recess 2b of the output shaft 2 and the difference in rotation angle becomes larger. Be blocked. Then, within the range of this maximum rotation angle difference, the second slit row 6b of the input shaft side disk 6 and the second slit row 7b of the output shaft side disk 7 have the same phase except in the zero range. There is no such thing. Further, the width of the optical path 44 is set to the second slit rows 6b and 7b.
1 pitch or more, the input shaft and the output shaft 2, that is, the output shaft side disk 7 of the input shaft side disk 6 is the housing 8
On the other hand, it is possible to detect whether the torque is within the zero range at any rotational position.

That is, the detection signal from the second photocoupler unit 15 is sent to the EPS controller 56 as a digital signal that clearly indicates whether the torque is within the zero range.

Therefore, when it is determined from the detection signal from the photocoupler second unit 15 that the torque is within the zero range, the input detected by the first photocoupler 24 (and the second photocoupler 29) of the photocoupler first unit 13 is detected. The rotation angle of the shaft side disc 6, that is, the input shaft side end of the torsion bar 3, and the output shaft side disc 7 that is the output shaft of the torsion bar 3 detected by the third photocoupler 34 (and the fourth photocoupler 39). If the difference between the rotation angles of the side ends is zero, the first slit row 6a of the input shaft side disk 6 and the first slit row 7a of the output shaft side disk 7 are incremented by the photocoupler first unit 13. It is judged that there is no error in the counting of the method. However, when it is determined from the detection signal from the photocoupler second unit 15 that the torque is within the zero range, the difference between the rotation angle of the input shaft side end and the rotation angle of the output shaft side end of the torsion bar 3 is zero. If not, it can be determined that an error has occurred in the counting of the first slit rows 6a and 7a by the increment method, and the count value of the difference in the rotation angle can be immediately corrected.

Then, by monitoring the absolute value and frequency of the correction, it is possible to detect mechanical slack in the photocoupler, deterioration of the calculation unit of the ESP controller 56, contact failure in various places, breakage of the torque detector itself such as disconnection. When the failure of the torque detector is detected, the operation of the power steering device is switched to the manual steering operation.

Here, taking an example in which specific numerical values are applied, assuming that the signal is quadrupled, for example, the first slit row 6a of the input shaft side disc 6 and the output shaft side disc 7 The number of slits in the first slit row 7a is at least (650/1 rotation)
However, if the spring rate of the torsion bar 3 is 15 kgf-cm / deg, the resolution of the torque detector is about 2 kgf-cm in terms of torque.

Further, the zero range of the torque due to the second slit row 6b of the input shaft side disc 6 and the second slit row 7b of the output shaft side disc 7 is ±
If the spring rate of the torsion bar 3 is set to 5 kgf-cm, the slit width of the second slit rows 6b and 7b theoretically becomes 1/3 deg, but may be practically 1 to 2 deg. . This is because the light quantity can be converted into a voltage by the light receiving element and the electronic circuit, and the voltage in the torque zero range can be set in a narrower range by the comparator.

Further, the maximum torque, that is, the maximum twist angle of the torsion bar 3 is set to about ± 7 deg.
It is appropriate to set the pitch of 7b to be slightly larger than 7deg.

Thus, in this embodiment, the first slit row 6a
The number of slits 7 and 7a and the number of photocouplers used (basically, two sets of photocouplers 24 and 34) are significantly smaller than those in the absolute system.

FIG. 8 shows another embodiment of the input shaft side disc and the output shaft disc, in which the zero torque range is detected by another method.

That is, in the figure, the first slit row 58a of the input shaft side disc 58 and the first slit row 59a of the output shaft side disc 59 are both the first slit row 6a ( And the same as the first slit row 7a) of the output shaft side disc 7, the second slit row 58b of the input shaft side disc 58 and the second slit row 59b of the output shaft side disc 59, The pitch is the second slit row 6b of the input shaft side disc 6 (and the second slit row 6b of the output shaft side disc 7).
The same as the slit row 7b), but both of them have a wider slit width and are fixed to the input shaft 1 and the output shaft 2 by shifting the 1/2 pitch phase from each other in the state where the torsion bar 3 does not twist and the torque is zero. To do. And the fifth photo coupler
The light emitting element 45 and the light receiving element 48 of 49 are arranged to face each other.

According to this alternative embodiment, the light emitting element 45 is in the zero torque range.
Since the light emitted from the light does not reach the light receiving element 48, and the light is received by the light receiving element 48 outside the zero range, a digital signal whose on / off state is opposite to that of the above-described embodiment is obtained.

FIG. 9 shows another embodiment 61 of the second unit of the photocoupler. In this other embodiment, the holder 62 is provided with the light emitting element 63 and the lens portion 64 with respect to the second slit row 6b of the disc 6 on the input shaft side. Then, the fixed fifth photocoupler 67 including the lens portion 65 and the light receiving element 66 is engaged, and the light emitting element 69 and the lens are attached to the holder 68 with respect to the second slit row 7b of the output shaft side disk 7. Part 7
Sixth photocoupler consisting of 0, lens section 71 and light receiving element 72
The fixed 73 is engaged, and at least one of the holder 62 and the fifth photocoupler 67 or the holder 68 and the sixth photocoupler 73 is provided along the input shaft side disc 6 or the output shaft side disc 7. It can be moved and fixed freely.

According to this another embodiment, when fixing the input shaft side disc 6 to the input shaft 1 and fixing the output shaft side disc 7 to the output shaft 2,
The mounting phase of the second slit rows 6b and 7b of both discs, that is, the mutual phase of the second slit rows 6b and 7b is arbitrary, and the fifth photocoupler 67 for the input shaft side disc 6 is used.
And the detection phase of the sixth photocoupler 73 with respect to the output shaft side disk 7 can be individually adjusted to make the signal phases in-phase.

In the above-mentioned embodiment, the disk using the input shaft side rotating body and the output shaft side rotating body is shown, but the present invention is not limited to this, and a cylindrical body or any other suitable body can be used. .

Further, although the light transmission type is exemplified, the present invention is applicable to an incremental type encoder such as a light reflection type, a magnetic type such as a magnescale, or a capacitance type which is one type of a video disc. Can be applied.

Also, although the quadruple frequency is exemplified as the doubling of the detection signal, this is because it is easy to quadruple the frequency when a signal with a phase shift of 1/4 pitch is used for determining the rotation direction. , 8 times, 16 times, etc. are not particularly limited.

Further, although the housing of the torque detector has been described as being separate from the steering gear assembly, it may be integrally incorporated or may be incorporated in the steering column assembly.

〔The invention's effect〕

As described above, the torque detector of the present invention connects the elastic member between the input shaft and the output shaft, and rotates integrally with the input shaft side end and the output shaft side end of the elastic member. An input shaft side rotating body and an output shaft side rotating body are provided, and an input is made from the difference between the rotation angle of the input shaft side rotating body detected by the first detecting means and the rotation angle of the output shaft side rotating body detected by the second detecting means. In the torque detector for detecting the torque applied to the shaft, a third detection means for detecting whether or not the torque applied to the input shaft is within a preset zero range is provided with an input shaft side rotating body and an output shaft side rotating body. Since the structure is characterized by being provided in association with the body, the structure of the rotation angle detection part is simplified, and therefore the torque detector as a whole is small and inexpensive, and the range of zero torque must be clearly defined. And therefore rotation angle detection It is possible to correct the miscount of the detector, and it is also possible to detect the failure of the detector itself by monitoring the absolute value and frequency of the miscount or correction, improving the reliability and safety essential for vehicles. The effect of being able to do is obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of an embodiment of the torque detector of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG.
FIG. 3 is an enlarged front view of a main part of the slit disk, FIG. 4 is an enlarged sectional view of the photocoupler first unit, FIG. 5 is a bottom view of FIG. 4, and FIG. 6 is an enlarged photocoupler second unit. FIG. 7 is a sectional view, FIG. 7 is a bottom view of FIG. 6, FIG. 8 is an enlarged front view of an essential part of another embodiment of a slit disk, and FIG.
It is a bottom view similar to FIG. 7 of another Example of a unit. 1 ... Input axis, 2 ... Output axis, 3 ... Torsion bar,
6,58 …… Input shaft side disc, 7,59 …… Output shaft side disc, 6a, 7a,
58a, 59a …… First slit row, 6b, 7b, 58b, 59b …… Second
Row of slits, 8 ... Housing, 13 ... Photocoupler first unit, 15,61 ... Photocoupler second unit, 1
7,43,62,68 …… Holder, 18,19 …… Auxiliary slit plate, 24,
29,34,39,49,67,73 …… Photo coupler.

Claims (12)

[Claims] 1. An input shaft side rotating body and an output shaft side, wherein an elastic member is connected between the input shaft and the output shaft, and the input shaft side end portion and the output shaft side end portion of the elastic member rotate integrally with each other. A rotating body is provided, and the torque applied to the input shaft is calculated from the difference between the rotation angle of the input shaft side rotating body detected by the first detecting means and the rotation angle of the output shaft side rotating body detected by the second detecting means. In the torque detector for detecting, a third detecting means for detecting whether or not the torque applied to the input shaft is within a preset zero range is associated with the input shaft side rotating body and the output shaft side rotating body. A torque detector characterized by being provided as follows. 2. The first to third detecting means include a light emitting element,
The torque detector according to claim 1, comprising a light receiving element that receives light emitted from the light emitting element and transmitted through the input shaft side rotating body and the output shaft side rotating body. 3. The torque according to claim 2, wherein the third detecting means transmits light through a slit array formed on the input shaft side disc and the output shaft disc in the zero torque range. Detector. 4. The third detecting means according to claim 2, wherein the third detecting means blocks light in a zero torque range through a slit array formed in the input shaft side disc and the output shaft side disc. Torque detector. 5. The first to third detecting means include a light emitting element,
The torque detector according to claim 1, comprising a light receiving element that receives light emitted from the light emitting element and reflected from the input shaft side rotating body and the output shaft side rotating body. 6. The torque detector according to claim 2 or 5, wherein a photocoupler including a light emitting element and a light receiving element is arranged on a printed circuit board together with an electronic circuit for processing an output signal of the photocoupler. 7. The torque detector according to claim 2, wherein the third detecting means includes a set of photocouplers associated with the input shaft side rotating body and the output shaft side rotating body. 8. The method according to claim 2, wherein the third detecting means includes a set of photocouplers associated with the input shaft side rotating body and a set of photocouplers associated with the output shaft side rotating body. 5
The torque detector described in the item. 9. A third detecting means includes a light emitting element, a light receiving element, an electronic circuit for converting an output signal of the light receiving element into a voltage signal, and a comparator for setting a voltage symbol of the electronic circuit within a narrow range. The torque detector according to claim 2, which is configured to include the torque detector. 10. The first to third detecting means comprises a magnetic domain formed in the input shaft side rotating body and the output shaft side rotating body, and means for detecting the magnetism of the magnetic domain. The described torque detector. 11. The first to third detecting means are constituted by means for detecting a change in electrostatic capacitance between the input shaft side rotating body and the output shaft side rotating body and the detecting section. The torque detector according to item 1. 12. The count result of the first and second detecting means is set to a third value.
Claim 1 which corrects according to the detection result of a detection means
The torque detector described in the item.