SU1657982A1 - Torque meter - Google Patents

Description

one

(21) 4680845/10

(22) 04.19.89

(46) 06.23.91. Bul P 23

(71) Penza Polytechnic Institute

(72) L.G.Kogelman, A.I.M. Shin, IL1. Frolov and P.II. Chernetsov

(53) 531.781 (088.8)

(56) USSR Author's Certificate V 1030677, kp. From 01 L 3/10, 1983.

USSR author's certificate K 132G694, cl. G 01 L 3/10, 1987.

(54) DEVICE FOR MEASURING TORQUE

(57) The invention relates to a measuring instrument and is intended to measure the torque on a rotating shaft. The aim of the invention is to improve the accuracy

A device containing an integrator 1 and a transformer converter 3, has a speed of 5, a comparator 5, a DC amplifier 4 and a thermistor 2 are inserted. 4, in the negative feedback circuit of which the primary winding of the transformer converter 3 is connected, and the output winding is connected to the second input of the comparator 5. The second output of the output winding and the forward input of the amplifier 4 is constant This current is connected to the earth bus, the output of the comparator 5 is the output of the device. 2 Il.

with

S

WITH/

The invention relates to a force-measuring technique; it is intended to measure the torque on a rotating shaft.

The purpose of the invention is to increase accuracy and speed.

Figure 1 shows the functional diagram of the device; figure 2 - timing charts of his work.

The device contains an integrator 1, a thermistor 2 with a resistance R ,, transformer converter 3 with input and output windings (primary and secondary) switched on, a DC amplifier 4 and a comparator 5. The output of the integrator 1 is connected to its input through a comparator 5 thermistor 2 is connected to the inverted input of amplifier 4, in the feedback circuit of which the primary winding of the transformer converter 3 is turned on, and the output winding (secondary) is connected to the second input of the comparator 5. The second output is output The windings and the direct input of amplifier 4 are connected by a ground bus, and the output of comparator 5 is the output of the device.

The device is designed to measure the torque on a rotating shaft of predominantly small diameter, so the shaft can be made isotropic at its different positions.

The device works as follows.

When turning on the power at the output of the comparator 5, a positive voltage appears with an amplitude U, which is fed to the input of the integrator 1, the signal at the output of which becomes

U

 YЈ t

O S

(one)

Where

WITH

the integrator time constant 1.

This voltage through a thermoresis; torus 2 R 1 is fed to the input of amplifier 4. The current D of the negative feedback circuit of amplifier 4 flows through the primary winding of the torque torque magnetoelastic transformer 3 and is changed by law

(2)

The current I is summed with the parasitic current 1P from the action of the EMF due to the speed effect.

1 + 1

(3)

It is assumed that during the period following the output pulses of the device, the frequency of rotation of the shaft is constant, the parasitic current is also I const, EMF, the induced output winding is directly proportional to the derivative

V

The output voltage of the torque converter 3, the windings of which are connected in opposite, is described by the expression

“„ Dt

 + In)

 dc

M +

one

WITH

 UN +

ЈRt

CO 5

(four)

where 1

with

50

EMF induced in the secondary winding (caused by the speed effect); M is the magnetoelastic inductance of the magnetoelastic transformer converter 3. This voltage is fed to the input of the comparator 5, to the other input of which the integrator 1 is connected. At the moment of time, with the voltage 1C and Uf,

+ i

and

with

(five)

Comparator 5 is switched. The signal at the output of the integrator 1 is determined by the expression

U,

UЈ

- TЈ,

- (with - with,)

ten

-Ґ

- (with - 2s,).

(6)

The current in the feedback circuit of the amplifier 4

15

- 7Tf Rt

(s - 2s (). (7)

The thermoreistor 2 is located in combination with the magnetoelastic transformer converter 3 at the shaft, i.e. has almost the same temperature as the shaft. The output voltage of the transformer converter 3

25

. - wr v

(eight)

at time with,

U.

and

Then

U9M

 1CO Ј g G

, - 4 (sl-2s.)

(9)

35

Comparator -5 switches. The whole process is repeated. Sola system of equations (5) and (9)

(YU)

- “T,

(eleven)

get the value of the time interval 2M

hh -t

It's obvious that

2M

S c ct

t

(12)

Thus, the period of the pulse from the comparator 5 is equal to

j - t4) + (cr - t,)

4M

Rt

Ep (i t

those. does not depend on the EMF induced in the secondary winding, caused by the speed effect.

When exposed to a temperature varying in a certain range, the parameters of the transformer converter 3 change as follows:

And - M0 (1), (14) where M is the mutual inductance of the transformer converter 3, changing under normal conditions;

 m is the coefficient determining the mutual inductance change per unit temperature change;

LT is the value of temperature change.

The thermistor 2 is selected so that the law of change of its Ri is identical to the law of change of the magnetic permeability of the shaft material, for example, the following:

Rt RЈ (1), (15)

where R, is the resistance of thermoresor 2 under normal conditions;

CP - T.K.S. thermistor 2. If you pick up 0 (O / m, then

t. + LMLT). Mo TLT R (

T is the period following the output pulses of the device when the temperature changes.

Thus, in the proposed device, the output signal does not depend on temperature and EMF caused by the speed effect.

Claims (1)

Invention Formula 6) A torque measuring device comprising an integrator J5 and a transformer converter, characterized in that, in order to increase accuracy and speed, a comparator, a DC amplifier and 2Q thermistor, and the integrator output is connected to its input through a comparator and connected via a thermistor to the inverse input of a DC amplifier, in a reverse circuit 25 of the connection of which the primary winding of the transformer converter is included, the secondary winding of which is connected to the second input of the comparator, while the second output of the secondary 30 windings of the transformer converter and direct input to the amplifier are constant. current is connected to the ground bus. I - - - - and 1CUPT 3 uh , Fig.}