RU2068550C1 - Torque meter - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: torque meter has measurement bridge incorporating resistance strain gauges 1-4, power supply source 5, current collecting contacts 6-11, amplifiers 12 and 13, divider 14. Current collecting contact 6, vertexes of supply diagonal of bridge, current collecting contact 7 are connected in series and linked to output of source 5. Vertexes of supply diagonal of bridge are connected through current collecting contacts 8 and 10 to inputs of amplifier 13. Vertexes of measurement diagonal of bridge are connected through current collecting contacts 9 and 11 to inputs of amplifier 12. Outputs of amplifiers 12 and 13 are connected to input of divider 14 which is output of torque meter. EFFECT: enhanced functional stability and reliability. 1 dwg

Description

 The invention relates to measuring technique and can be used to measure the parameters of rotating shafts, such as stress, deformation, as well as torques and power on the shafts.

 It is known [1] a device for measuring torque, comprising a measuring bridge located on the shaft, current collector contacts, a power source, an amplifier, a subtractor, and a resistor.

 A disadvantage of the known device is the low accuracy of the measurement.

Closest to the invention in technical essence is a torque meter containing a measuring bridge located on the shaft, current collector contacts, power supply, amplifier, subtractor, multiplier and resistor [2]
A disadvantage of the known device is the lack of accuracy due to the destabilizing effect of disturbing factors on the strain gages of the bridge and the resistor made of different materials and installed in different conditions.

 The drawing shows a structural diagram of a torque meter.

 The torque meter contains a measuring bridge, consisting of strain gauges 1 4, power supply 5, current-collecting contacts 6 11, amplifiers 12 and 13, division unit 14. A current collector contact 6, vertices of the power supply diagonal of the bridge containing strain gauges 1 4, and current collector contact 7 are connected to the output of the power supply 5. The vertices of the power diagonal, respectively, through the collector contacts 8 and 10 are also connected to the inputs of the amplifier 13. The vertices of the measuring diagonal of the bridge, respectively, through the collector pins 9 and 11 are connected to the inputs of the amplifier 12. The outputs of the amplifiers 12 and 13 are connected to the inputs of the division unit 14, the output of which is the output of the device.

 The torque meter operates as follows.

(1)
где К₁ коэффициент усиления по напряжению усилителя 12;
U напряжение источника 5 питания;
ΔR изменение сопротивления тензорезистора, пропорциональное крутящему моменту;
R сопротивление одного тензорезистора;
R₆, R₇ переходные сопротивления токосъемных контактов 6 и 7 соответственно.The signal from the measuring diagonal of the bridge through the collector contacts 9 and 11 is fed to the inputs of the amplifier 12, the output voltage of which is described by the expression

(one)
where K ₁ the voltage gain of the amplifier 12;
U voltage of power supply 5;
ΔR is a change in the resistance of the strain gauge proportional to the torque;
R is the resistance of one strain gauge;
R ₆ , R ₇ transient resistance of the current-collecting contacts 6 and 7, respectively.

 The amplifier 12 has a high input resistance, so the transition resistance of the current-collecting contacts 9 and 11 do not affect the measurement result.

(2)
где К₂ коэффициент усиления по напряжению усилителя 13.The signal from another diagonal of the bridge through the collector contacts 8 and 10 is fed to the inputs of the amplifier 13, the output voltage of which is described by the expression

(2)
where K _{2 is} the voltage gain of the amplifier 13.

(3)
Так как входное сопротивление усилителя 13 очень высоко, то переходные сопротивления токосъемных контактов 8 и 10 также не оказывают влияния на результат измерения.Signals (1) and (2) from the outputs of amplifiers 12 and 13 are fed to the inputs of the division unit 14, the output signal of which is determined by the expression

(3)
Since the input resistance of the amplifier 13 is very high, the transition resistance of the current collector contacts 8 and 10 also does not affect the measurement result.

 As can be seen from expression (3), the use of this invention does not require a stable power source, reduces the error from the instability of the transition resistances in the current collector contacts and from the destabilizing effect of disturbing factors on the circuit elements.

Claims (1)

 A torque meter containing a measuring bridge located on the shaft, a power source connected through one current collector contacts to the vertices of the measuring bridge power diagonal, and an amplifier connected through other current collector contacts to the vertices of the measuring diagonal, characterized in that a division unit is inserted into it and the second amplifier with current-collecting contacts, through which it is connected to the vertices of the diagonal of the power supply of the measuring bridge, and the outputs of the amplifiers are connected to the inputs of the division unit, the output of which is output by a torque meter.