JPH01276033A - Detecting device for minute displacement - Google Patents

Abstract

PURPOSE:To measure a minute angle displacement with high accuracy by detecting a phase variation of magnetic pulses by tow pieces of permanent magnets. CONSTITUTION:Magnetic pulses by permanent magnets 2, 3, respectively for turning by using an axis 1 by magnetization to a permanent magnet material as an axis are detected by sensors 4, 5. Based on a phase variation of the magnetic pulses which are detected by these sensors 4, 5, an angle displacement by the axis 1 is detected. Accordingly, being different from the case of a gear, etc. are used by magnetization of a minute permanent magnet, a minute angle displacement can be measured with high accuracy by simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a measuring device for measuring transmission torque and relative positional displacement of a power transmission shaft, and particularly relates to a minute displacement detecting device that can accurately detect minute values. It is something.

(Prior Art) Generally, when torque is applied to a power transmission shaft, regardless of whether it is a one-rotation shaft or a fixed shaft, strain is generated in the power transmission shaft in a direction of 45' with respect to the axial direction.

Conventionally, in order to detect the torque acting on the transmission shaft, as shown in FIG. Displacement of the relative position of the teeth is measured using a magnetic sensor or photomultiplier 24.2.
It was measured by detecting at 5.

(Problems to be Solved by the Invention) In the above-mentioned conventional technology, the relative displacement of two gears is measured, so the machining accuracy of the teeth determines the measurement accuracy of torque. Accuracy is limited in terms of cost, and it has not been possible to measure minute changes in relative position, that is, minute torques.

In addition, when attempting to improve the machining accuracy of gears due to measurement accuracy, there is a drawback that the device becomes expensive in terms of cost.

(Means for Solving the Problems) The present invention has been made to solve the problems in the conventional technology, and includes two permanent magnets having a predetermined interval,
It consists of a magnetic sensor that detects the magnetic pulses of the two permanent magnets by detecting a change in the phase of each magnetic pulse.

The present invention relates to a minute angular displacement detection device that measures a change in the relative position of the two permanent magnets.

(effect) The minute displacement detection device of the present invention has the above configuration.

By measuring the pulses emitted from each of two permanent magnets having a predetermined interval, and detecting the phase difference between the pulses around 9 due to changes in the conditions of the object to be measured, such as torque acting on the shaft, Relative displacement between permanent magnets can be measured.

Therefore, if the relationship between the relative displacement between the two permanent magnets and the change in the conditions of the object to be measured is measured in advance.

By measuring the relative displacement of the permanent magnets, changes in the conditions of the object to be measured can be measured.

(Example) The following is an example of the present invention. The torque detection device for the transmission shaft will be described in detail based on FIGS. 1 to 4.

FIG. 1 shows a torque detection device according to one embodiment.

1 is a transmission shaft made of material S43C and has a diameter of 10φ, 2 and 3
The main component is Fe-CrCo. It is a permanent magnet made of a magnetic material with a diameter of 30φ and magnetized with 120 pulses on the outer periphery.

4.5 is an MR element for detecting the magnetic pulses of the permanent magnets 2 and 3, and 6.7 is a lead wire for guiding the magnetic pulses of the MR elements 4 and 5 to a measuring instrument (not shown). It is.

Note that the MR elements 4 and 5 are Hall elements, etc.

It is not necessarily limited to an MR element as long as it can detect magnetic pulses.

Moreover, permanent magnets 2 and 3. As shown in FIG.
The coil 9 connected to the permanent magnet material 2a,
By rotating 3a by a predetermined angle to oscillate the coil and synchronize it.

360 perpendicular magnetizations were performed from the surface to the entire circumference.

Next, the operation will be explained with reference to FIG.

If the permanent magnets 2 and 3 are magnetized so that their magnetized positions completely match in the circumferential direction, the magnetic pulses detected by the MR elements 4 and 5 will have a phase difference as shown in FIG. There is no exact match.

When torque is applied to the transmission shaft 1, the transmission shaft 1 is twisted, the magnetized positions of the permanent magnets 2 and 3 are shifted, and the magnetic pulses detected by the MR elements 4 and 5 are also affected as shown in FIG. A phase difference δ occurs. The phase difference δ is (δ/l wavelength) because the number of magnetized magnets on the permanent magnets 2 and 3 is 360.
Since the angle changes in degrees, the torque value can be calculated from the rigidity of the material of the transmission shaft l.

(Effects of the Invention) As described above, the present invention can easily improve the accuracy of magnetization, thereby reducing costs and improving measurement accuracy.

It is also possible to accurately detect small angles.

Further, the device has the advantage of being compact and having improved durability since it is a non-contact type.

[Brief explanation of the drawing]

Fig. 1 shows a torque detection device for a transmission shaft which is an embodiment of the present invention, Fig. 2 shows a magnetizing device for a permanent magnet in Fig. 1, and Fig. 3
The figure shows an example of the present invention. The magnetic pulse when no torque is applied, Figure 4, is the same as that in Figure 3, and the magnetic pulse when torque is applied, Figure 5.
The figure shows a conventional technique. 1... Transmission shaft 2.3... Permanent magnet 2a,
3a... Permanent magnet material 4.5... MR element 6.7... Lead wire 8...
・Magnetic core material 9...Coil lO...Power supply
11...Switch patent applicant Komatsu Ltd. Representative (patent attorney) Oka 1) Kazuyuki Figure 1 Figure 2

Claims (1)

[Claims] It consists of two permanent magnets having a predetermined interval and a magnetic sensor that detects the magnetic pulses of the two permanent magnets, and detects the change in the phase of each magnetic pulse.
A minute displacement detection device characterized by measuring changes in the relative positions of two permanent magnets.