JPS60177231A - Torque detector - Google Patents

Abstract

PURPOSE:To detect torque stably with good responsibility without contacting by using a torque sensor which the reverse effect of magnetostriction and a position sensor, and averaging momentary torque. CONSTITUTION:The position sensor 1 arranged corresponding to the projection 29 of a torque transmission shaft 27 outputs one pulse on every turn. Momentary torque TQ outputted by a cross type torque sensor 2 constituted by putting a U- shaped exciting core 20 and a using core 21 in corss relation is read in a microcomputer 7 synchronously with the output of a pulse generator 12. Every time a pulse is outputted by the position sensor 1, data on the momentary torque TQ stored in one cycle are averaged and applied torque TQR is calculated from the difference TQZ in mean torque TQZ in an unloaded state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetostrictive torque detector suitable for measuring torque during rotation of a vehicle.

[Background of the invention]

Conventionally, the 1~lux sensor that utilizes the reverse effect of magnetostriction in which magnetic permeability changes due to stress is well known, and is published in the magazine ASEA JOURNAL of Sweden's ASEA,
1960. VOL, 33. &3. P23-P32. U
, S, P, Na4.135,391 and JP-A-53-7
It is described in detail in Publication No. 7572 and the like. These known examples are:
These are cross-type and ring-type torque sensors.

By the way, this type of torque sensor absorbs output fluctuations caused by variations in magnetic permeability in the surface layer of the rotating shaft.
Usually a low pass filter is used. However, the cut-off frequency in this case is limited by the minimum rotational speed of the torque transmission shaft, which is 5-10 Hz for automobile engines. For this reason, there is a problem in that the responsiveness of this type of torque sensor is low regardless of the rotational speed.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a torque detector that detects the torque of a rotating shaft of a vehicle in a non-contact manner with good responsiveness and stability in °C.

[Summary of the invention]

The present invention detects a fixed angle of the torque transmission shaft using a position sensor, measures the instantaneous torque multiple times at fixed time intervals between the fixed angles, and calculates the applied torque by taking the average. It is something.

[Embodiments of the invention]

Hereinafter, a torque detector according to the present invention will be explained in detail with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG.
The figures are structural diagrams showing the mounting state of the position sensor and torque sensor, FIG. 3 is an operation timing diagram, FIG. 4 is a torque characteristic diagram, and FIGS. 5 and 1 are operation flow diagrams of the microcomputer.

In FIG. 1, 1 is a position sensor that detects the rotation angle of the torque transmission shaft, and as shown in FIG.
The housing 28 is mounted opposite to the housing 28 . In this embodiment, there is one protrusion 29 and outputs one pulse per rotation. It should be noted that detailed explanation will be omitted since this position is limited. Next, 2 is a torque sensor, which is of the cross type described in the prior art.

The cross shape is a structure in which a U-shaped excitation core O and a U-shaped detection core 21 are crossed, as shown in FIG. Here, an excitation winding is wound around the excitation core 20, a detection winding 23 is wound around the detection core 21, and an excitation winding 22 is wound around the detection core 21.
is excited by the AC oscillator 5 and forms a magnetic path shown by a broken line. These cores 20 and 21 are fixed to the mounting plate 26 via non-magnetic spacers. 25 is a sensor cover. Since 27 is a bookshelf for a vehicle, mechanical strength is taken into consideration and surface treatment is performed, but magnetic permeability is not considered at all, so the magnetic permeability of the surface layer usually varies widely. 3 is a waveform shaping circuit, and 4 is a full-wave rectifier circuit, which amplifies the output signal of the torque sensor 2 and performs full-wave rectification. 6 is an A/D converter, 7 is a microcomputer,
11 is a zero torque setting switch, 12 is a pulse generator 13 is an integrating circuit, and these constitute the controller 8.

Now, as shown in the rotation angle-torque characteristics in Figure 3,;-
Luc transmission Ii! The output voltage Q1 of the torque sensor 2 varies greatly due to variations in the magnetic permeability of the lI27.

However, even when a load is applied, it changes in the same phase, so if you always measure the torque at the same location on the torque transmission shaft, you can accurately detect the applied torque. - When mounted on a vehicle, the relationship between torque and output voltage is proportional as shown in Figure 4. Even if position sensor J is used, a constant rotation angle can be accurately detected due to the effects of vibration, shaft eccentricity, rotation speed, etc. Rotation will cause some variation in the torque sensor output. However, this problem can be solved by measuring the torque at multiple points and averaging it.

Next, the operation of the microcomputer 7 will be explained in detail using FIG. First, when the power is turned on, step l],
Turn on switch 1.1 (CAL-SW) at O.
It is determined that it is off, and if it is on, it moves to a routine that measures torque under no load, and if it is off, it moves to a normal torque measurement routine. *First, we will describe the no-load torque measurement routine. At first.

In step 42, the pulse number count value CN of the pulse generator (hereinafter abbreviated as TM) 12 is cleared and a rise of the signal output (hereinafter abbreviated as PS output) 10 of the position sensor 1 is determined, and if it is not a rise, the process proceeds to step 45. Go ahead and T here
Determine the rise of M12, add 1 to the count value CN, read the instantaneous torque TQ at that time, and store it in memory Q (CN
). Thereafter, the process returns to step 43 and the above-described operations are repeated. After this, when the shaft rotates once and the PS1 output signal rises, the process moves to step 44, where the arithmetic mean of the instantaneous torques TQ stored up to now is determined, and the no-load torque is determined as TQ.
Store in Z. In order to measure the no-load torque in this way, it is sufficient to put the vehicle in a no-load state and turn on the switch 11, and the setting can be made as many times as necessary.

Next, the torque measurement routine will be explained. First, the pulse number count value CN is cleared, and the process moves to step 49, where the rise of the PS output is determined. (CN) is stored. Next, the process moves to step 53, where the upper limit value CC of the count value CN is set.
When the upper limit value CC is exceeded, the process moves to the torque calculation routine 54.

On the other hand, if it does not exceed the limit, the process returns to step 49 and the above-described process is repeated. Then, at the time of the rise of the PS output, the arithmetic mean of the instantaneous torque data TQ stored so far is calculated, and the applied torque TQR is calculated from the difference from the no-load average torque TQZ, and is output in step 58. Thereafter, the process returns to step 48 and the above-described operations are repeated.

As described above, according to the present embodiment, since the torque is calculated for each revolution of the shaft, the detection time becomes faster depending on the rotation after rotation at a rotation speed of 60 rpm or more, and responsiveness is improved. Furthermore, since the instantaneous torque TQ is measured multiple times per rotation and the average value is calculated as the applied torque, variations in output due to vibrations, shaft eccentricity, etc. are also reduced. Another advantage is that the no-load torque calibration can be easily transmitted with a single switch.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a torque sensor and a position sensor that utilize the reverse effect of magnetostriction are used.
By averaging the instantaneous torque, there is an excellent effect of being able to perform non-contact, highly responsive, and stable torque measurement.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing one embodiment of the present invention, Fig. 2 is a mounting structure diagram of the position sensor and torque sensor in Fig. 1, Fig. 3 is an operation timing diagram of Fig. 1, and Fig. 4 is a FIG. 1 is a characteristic diagram of applied torque in the embodiment, and FIG. 5 is an operation flow diagram of the microcomputer in FIG. 1. 1...Position sensor, 2...Torque sensor, 4...
Full-wave rectifier circuit, 5...excitation oscillator, 6...A/D
Converter, 7... Microcomputer, 11... Switch, 12... Pulse generator, 27... Torque transmission shaft, 29... Projection. Condolence, 5/J No41jJ fpjB Tono Lri

Claims (1)

[Scope of Claims] 1. A position sensor that detects a constant rotation angle position of a torque transmission shaft of a vehicle, a torque sensor that detects torque of a torque transmission shaft by a change in magnetic permeability, and a shaft torque that detects a shaft torque in response to a signal from the torque sensor. In a torque detector composed of a calculating microcomputer and a 71X, instantaneous torque is detected multiple times in synchronization with the signal from the position sensor, and the averaged torque is calculated by the microcomputer each time the signal from the position sensor is generated. A torque detector characterized by: 2. The torque under no load is stored in advance in the storage section of the microcomputer, and the difference between the measured torque and 1 herk under no load is calculated as the applied torque. The 1-lux detector described.