SU708182A1 - Torque meter - Google Patents

Description

I

The invention relates to the field of force-measuring equipment, in particular, devices for contactless measurement and threshold torque control on rotating shafts, and is intended for use in deep drilling machines and adaptive control machines.

The known devices for measuring torque on rotating shafts, containing an electromagnetic transducer designed to convert mechanical stresses arising in the surface layers of the shaft, into a proportional electrical signal at its output, an amplifier transducer: designed to amplify it and convert an electrical signal, the electromagnetic converter coming from the output, into an electrical signal of the required type, and the measuring unit do not provide the required accuracy measurements 1, 2.

The closest to the technical essence of the invention is a device for measuring torque, containing a magnetoelastic converter in the form of a cylinder of ferromagnetic material mounted on a shaft, an electromagnetic converter installed with a gap coaxial to the magnetoelastic converter, a source of alternating voltage for supplying an electromagnetic converter, a converter the output signal associated with the first input with the output of the electromagnetic converter, the moment calculator and a display unit 3.

The disadvantage of such a device is low measurement accuracy due to the averaging of the measured torque over the measuring time interval, as well as during fluctuations in the shaft rotation speed.

The aim of the invention is to increase the measurement accuracy.

This is achieved due to the fact that in the proposed device, the moment calculator includes a synchronization unit, a memory unit, a memory management unit and a subtraction unit, the output of the synchronization unit is connected to the input of the memory management unit and the second input of the output converter, the output of which is connected to the first inputs of the memory unit and the subtraction unit, the second input of the memory unit is connected to the output of the memory control unit, and the output is connected to the second input of the subtraction unit, the output of which is connected to the input of the display unit.

The block diagram of the proposed device is shown in the drawing.

The device consists of a magnetoelastic converter 1, an electromagnetic converter 2, an alternating voltage source 3, an output signal converter 4, a display unit 5, a synchronization unit 6, a memory management unit 7, a memory unit 8, and a subtraction unit 9, with blocks 6-9 form the moment calculator 10.

The magnetoelastic transducer 1 is a cylinder of ferromagnetic material mounted on a shaft and is designed to convert mechanical stresses arising in the surface layers of the shaft into a change in the magnetic characteristics of the cylinder. Coaxially to the shaft with a gap relative to the magnetoelastic transducer 1 located on it, an annular electromagnetic system is installed, comprising an excitation circuit and a measuring circuit. The electromagnetic system forms an electromagnetic transducer 2, which transforms the changes in the magnetic characteristics of a material occurring in a magnetoelastic transducer into a proportional electrical signal. The alternating voltage source 3 is designed to feed the excitation windings of the electromagnetic converter 2. The converter 4 is designed to convert the output signal of the electromagnetic converter 2 into a binary w-bit. The synchronization unit 6 is intended for forming 1 and pulses, the moment of occurrence of which depends on the angular position of the rotating shaft. It forms n pulses per shaft revolution. The memory unit 8 is designed to record, store and read numerical information about the background coming from the converter 4 in the absence of a moment on the shaft at those angular positions of the rotating shaft at which the formation of pulses occurs by the synchronization unit 6. The memory management unit 7 is designed to select one of the n addresses of the memory unit 8 (each angular position of the rotating shaft at which the pulses are formed by the synchronization unit 6 corresponds to a specific address of the unit 8) to form commands for recording instantaneous values of the initial output signal of the converter 2 at the selected address in block 8 at the first shaft rotation (there is no moment at the same time), to form commands for reading information from the corresponding addresses

memory block 8 at subsequent revolutions of the shaft.

The subtraction unit 9 is designed to calculate the difference between the numbers corresponding to the instantaneous total background values of 4 moments periodically received from the output signal converter 4 and the numbers read at the corresponding addresses of the memory block 8 that carry the information about the instantaneous background values recorded previously . The display unit 5 is designed to visually monitor the measured torque.

The operation of the device is as follows.

When the device is turned on, an initial output signal (background) appears at the output of the electromagnetic transducer 2, depending on the angular position of the shaft as it rotates. From the output of the electromagnetic converter 2, this initial output signal is fed to the first input of the output signal converter 4. When the first pulse from the output of the synchronization unit 6 arrives at the second input of converter 4, a t-bit binary number is formed directly proportional to the instantaneous output the signal of the electromagnetic converter 2. Simultaneously from the output of the synchronization unit, this pulse is fed to the input of the memory control unit 7, which generates a write command for The first address of block 8 of the memory of the number from the output of the converter 4. Subsequently, when the synchronization block b comes out of the output of each i-ro pulse (i-2,3 ...) to the second input of the converter 4, a binary number will be generated at its output, Mo is proportional to the instantaneous value of the initial output signal at the angular position of the shaft corresponding to the instant of formation at the output of the synchronization unit 6 of the i-ro pulse. At the same time, when each i-ro pulse arrives from the output of the synchronization unit 6 to the input of the control unit 7, a command to write the number from the output of the converter 4 to the ith address in the memory unit 8 will be generated at its output.

After the first revolution of the shaft, at the output of the block 6 an nh-1st pulse is formed. In this case, the angular position of the shaft will be exactly the same as at the moment when the first impulse is formed at the output of the block 6. When the 1 p pulse arrives from the output of the 6 p – f block, a binary number is formed at its output 4 directly proportional to the instantaneous value of the initial output signal at a given angular position of the shaft.

At the same time, when a sync p + 1-th pulse arrives at the output of block 7, its output will be generated

read command at the first address of block 8, in which information is recorded on the instantaneous value of the initial output signal at the same angular position of the shaft. Read on the first address of the block number 8 is fed to the second input of block 9.

Since the instantaneous value of the output signal of converter 2 in the absence of torque is constant for the same angular position of the shaft during its rotation, the number at the output of converter 4 at the time of forming at the output of synchronization unit 6 of the n + 1-th pulse will be equal to recorded at the first address of the memory block 8. The output of block 9 subtraction will be “O, which is fed to the input of block 5 of the display. The same picture will be observed when n + 2, n + 3 ... and all subsequent pulses are formed at the output of synchronization unit 6, in the absence of a steeply decelerated torque.

When a torque appears on the rotating shaft, the output from the synchronization unit 6 of each successive pulse to the second input of the converter 4 will cause a t-bit binary number directly proportional to the instantaneous value of the total output signal (background + + moment) to form at its output, corresponding to a given angular position of the shaft. From the output of converter 4, this number will be sent to the first input of subtraction unit 9, the second input of which will receive the number from the output of the memory block read by the command of control unit 7 from the address where the instantaneous value of the initial output signal is written at the same angular position of the shaft. Read commands are formed at the output of control unit 7 when pulses arrive at its input from synchronization unit 6 in such a way that each pulse corresponds to a strictly defined address of memory unit 8.

As a result, binary gp-bit numbers, directly proportional to the instantaneous values of the torque acting on the shaft, are sequentially generated at the output of the subtraction unit 9. These numbers from the output of subtraction unit 9 are fed to the input of display unit 5, which provides visual numerical information about the instantaneous torque value.

Claims (3)

1. USSR Author's Certificate No. 502252, cl. G 01 L, 1974. 2. US patent number 3340729, cl. 73-136, published. 1967. 3. For registration number 2424154 / 18-10, cl. G 01 L3 / 10; 1976 (prototype).