JPS6126613B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a torque detection device that connects a drive shaft and a load shaft with a torsion bar and detects the torsion angle of the torsion bar to detect transmitted torque.

For example, as shown in FIG. 1, this type of torque detection device includes a drive shaft 1 such as an electric motor shaft and a load shaft 2.
are connected via a torsion bar 3, and the drive shaft 1
Detecting elements 6, 7 are constructed by attaching, for example, a permanent magnet piece to one part of the discs 4, 5 provided on the load shaft 2, respectively, and when the load shaft 2 is in a no-load state on the fixed part, the detecting element 6 , 7 are provided, and by the phase difference (time difference) of the detection pulses output from the detectors according to the rotation,
It is designed to detect torque.

However, each of the detectors 8 and 9 outputs one pulse depending on the position facing the detection element, and in order to detect the phase difference between the outputs, a detection circuit including a flip-flop and a monomulti is used.
For this reason, it has disadvantages such as being prone to errors due to noise, having a complex circuit, and having low responsiveness.

In the present invention, a large number of detection elements are provided at a constant pitch on a drive shaft and a load shaft, and a plurality of detectors are provided opposite to the detection elements and mutually offset relative to the pitch, and for each axis. It is possible to obtain a detection circuit using comparators, AND elements, OR elements, and other arithmetic elements that generate multi-phase detection signals and do not have memory functions such as comparators, AND elements, OR elements, and whose outputs are not affected by noise continuously. This is what I did.

In the embodiment shown in FIG. 2, 4 is a disk fixed to the drive shaft, and 10 is a pitch P on the outer periphery of the disk.
A large number of detection elements are provided, for example, 36 at a pitch of 10°. 11, 12, 13 are three detectors facing the detection element 10, and the pitch P
It consists of a magnet and a coil with legs equally spaced from each other, and they are installed on a fixed part at a distance of (K+1/3)P (where K is an integer) from each other.

5 is a disk fixed to the load shaft, and like the disk 4, it has the same number of detection elements 2 at the same pitch as the detection elements 10.
It has 0. 14, 15, 16 are detectors facing the detection element 20, and the detectors 11, 1
2 and 13, and the detectors on the drive shaft side and the load shaft side have the same phase with respect to each detection element as shown in the figure in the no-load state. 21 to 26 are comparators, 31
- 36 are AND circuits that output the AND of the inverted signal of one input and the other input signal; 41 - 46 are AND circuits that output the AND of the two inputs; 51, 5;
2 is an OR circuit.

FIG. 3a shows a time chart when a positive torque is applied to the load shaft and the rotating plate 5 is delayed in phase by L from the rotating plate 4 of the drive shaft.

Three detectors 11, 12,
13 outputs three-phase detection outputs A ₁ , A ₂ , and A ₃ whose phases differ by 1/3 pitch. Similarly, detectors 14, 15 facing the disk 5 on the load shaft side,
3-phase detection outputs A ₄ , A ₅ , A ₆ whose phase is shifted by L according to the torque from the above-mentioned detection outputs from 16.
is obtained. These detection outputs are compared with constant values by comparators 21 to 26, respectively, and the output pulses are
Obtain _B1 to _B6 . This output pulse is applied to the AND circuits 31 to 36 by the inverted signal of the output pulse of each detector and the next output pulse signal of the detector on the drive shaft side and the load shaft side respectively, and the logic of both pulse signals is The pulse signals C ₁ to C ₆ are output as waveform-shaped pulse signals at steep zero-crossing points of the detection outputs A 1 to A 6 by multiplying the detected outputs A ₁ to A ₆ . The pulse signal C ₁ on the drive shaft side,
AND circuits 41, 42, 43 for C ₂ and C ₃ , respectively
In addition, the pulse signals C ₆ , C ₄ , C ₅ of the previous phase on the load shaft side are respectively applied to the other input ends of the AND circuits 41 , 42 , 43 , and the signals C ₁ , C ₆ , Output signal of AND of C ₂ and C ₄ , C ₃ and C ₅
D ₁ , D ₂ , D ₃ and the drive shaft side pulse signal C ₁ ,
AND circuits 44, 45, and 46 output the AND circuits of C ₂ and C ₃ and pulse signals C ₅ , C ₆ , and C ₄ of the next phase on the load axis as output signals D ₄ , D ₅ , and D ₆ . . Therefore, the AND circuit 41,4
Output signals D ₁ , D ₂ , D ₃ having a width L corresponding to the torque are obtained from the AND circuits 44 and 43 .
No output signal is output from 45 and 46. By adding these output signals D ₁ , D ₂ , and D ₃ in the OR circuit 51 and adding the detection signal E ₁ to an arithmetic unit (not shown) to calculate the average value over a unit period, the phase within a range of 10°/3 or less can be obtained. It is possible to accurately detect the deviation and calculate the torque applied to the load shaft accordingly.

In addition, when a negative torque is applied to the load shaft, the rotating plate 5 advances in phase by L according to the torque than the rotating plate 4 as shown in FIG. 3b, and the output pulses B ₄ to _{B 6} are output pulses B ₁ ~ B ₃ is advanced by phase L, pulse signals C ₄ ~ C ₆ are also advanced in phase from pulse signals C ₁ ~ C ₃ , outputs D ₁ ~ D ₃ of AND circuits 41 ~ 43 become zero, and AND circuits 44 ~ 46 The same outputs D ₄ to _{D 6} as in the case of positive torque are detected, and the OR circuit 5
2, a detection signal E ₂ is obtained.

In this way, in the present invention, a plurality of detection elements are provided on the drive shaft and the load shaft at a pitch of P, and a plurality of n detectors are provided facing the detection elements at an interval of (K+1/n)P. Since logical operations are performed by combining the same multi-phase waveform outputs obtained from the detectors, there is no need to use conventional flip-flops or monomultis as elements that make up the arithmetic circuit, making it resistant to noise. vessel,
It can be configured with AND circuits and OR circuits, which not only eliminates errors caused by noise and simplifies the circuit configuration, but also improves detection accuracy depending on the number of detectors, making it possible to determine whether the torque is positive or negative. It is possible.

Note that the detector is not of the magnetic type shown in the embodiment, but can also be optically used to detect the light beam passing through the slit with a light receiver.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing a conventional example of a torque detection device, FIG. 2 is a circuit diagram of an embodiment of the present invention, and FIGS. 3a and 3b are time charts of FIG. 2. 1 is a drive shaft, 2 is a load shaft, 3 is a torsion bar, 4 and 5 are disks, 6 and 7 are detection elements, 8 and 9 are detectors, 10 and 20 are detection elements, 11 to 16 are detectors, 21 ~26 is a comparator, 31~36 and 4
1 to 46 are AND circuits, and 51 and 52 are OR circuits.

Claims (1)

[Claims] 1. In a torque detection device that connects a drive shaft and a load shaft with a torsion bar and detects torque based on the amount of rotational phase deviation between the drive shaft and the load shaft due to the torsion angle of the torsion bar, Each axis has the same number of detection elements arranged at a pitch P, and n pieces (n>
1) A detector was provided, the detectors of each axis were arranged at intervals of (K+1/n)P (K is an integer), the output of the detector was shaped into a waveform, and the output pulse was inverted. It is equipped with an AND circuit that sends out an AND signal of the signal and an output pulse of the next phase, and an AND circuit that outputs an AND signal of the AND circuit on the drive shaft side and an output signal of the AND circuit of a different phase on the load shaft side. A torque detection device characterized in that an AND circuit is provided to send out a signal, and an output pulse having a width proportional to the torque is sent out.