ZJ type torque speed sensor
The instrument is installed between the power transmission shafts. It is used in conjunction with the TR-1 torque speed power measuring instrument and the CZ magnetic powder brake to measure the power of various engines, motors, fans, compressors, hydraulic pumps, gearboxes, etc. Torque speed power of machinery and transmission machinery in the range of 0-6000 rpm. Among them, ZJ is a sensor that outputs two voltage signals with phase difference through magnetoelectric conversion, and TR-1 is a single-chip microcomputer measuring instrument with printing and display. CZ type magnetic powder brake excitation current generates adjustable damping torque. It is an ideal loader for complete set of dynamometers. Please refer to the relevant manual for the specific use of TR-1 and CZ. The company provides turnkey engineering dynamometer systems.
ZJ torque sensor is mainly composed of torque shaft, magnetic detector, drum and housing. The magnetic detector includes two pairs of internal and external gears, permanent magnetic steel and induction coils. The external gear is installed at both ends of the measurement section of the torsion shaft; inside the internal gear drum, opposite to the external gear, permanent magnetic steel is installed in the drum next to the internal gear. Permanent magnetic steel, the inner and outer gears form a ring-shaped closed magnetic circuit, and the induction coil is fixed in the two ends of the casing. Driven by the drive motor, the internal gear rotates with the drum.
The internal and external gears are displacement gears and do not mesh with each other. The top six of the gears have a working air gap. The internal and external gears have the narrowest air gaps when they are opposite. During the relative rotation of the internal and external gears, the tooth tops and the cogging alternately oppose each other. When the tooth position is relatively rotated, the working air gap changes periodically, and the magnetic resistance and magnetic flux of the magnetic circuit change accordingly. A voltage signal that approximates a sine wave is induced, and the change in the instantaneous value of the signal voltage is consistent with the change in the relative position of the internal and external gears.
If the projections of the gears of the two sets of detectors coincide with each other, the phase difference between the two sets of voltage signals is zero. During installation, the projections of the two internal gears are coincident. The two external gears on the torsion shaft are installed by shifting half of the teeth. Therefore, the two voltage signals have a phase difference of half a period, that is, the initial phase difference is α0 = 180 °. If the gear is 120 teeth, the indexing angle is 3 °, and the phase difference is 180 °, the corresponding external gear shifts by 1.5 °.
When the torsion shaft is subjected to torque, a torsion angle β is generated, and the misalignment angle of the two external gears becomes 1.5 ° ± β. The phase difference angle of the two voltage signals accordingly becomes: α = 120 × (1.5 ° ± β) = 180 ° ± 120β.
The twist angle is proportional to the torque, so the change in twist angle is proportional to the torque, that is, the change in phase difference angle △ α = α-α0 = ± 120β = 120K1M = KM where K1 is the proportionality coefficient of phase difference angle and torque , K = ± 120K1, “±” indicates the direction of rotation.
Assuming that the diameter of the torsion shaft measurement section is d, the length is L, and the shear elastic modulus of the torsion shaft material is G, then K1 = 32L / πdG. Input the two voltage signals of the sensor into the TR-1 torque and speed power measuring instrument. The voltage signals are amplified, shaped, phase-checked, and converted into counting pulses through the meter. Then the count and display can be directly read out the torque and speed. Measurement results.
Because it adopts the magnetoelectric conversion, phase difference principle and digital display torque speed measurement method, it can perform stable, reliable, fast and sensitive high-precision measurement. It has the following characteristics:
1.Can measure static torque
When the torque arm is fixed at one end of the torque shaft and locked at the other end, as long as the drive motor of the sensor is turned on, the output signal can be obtained, and the sensor can be easily statically calibrated. Of course, sensors that have passed the static calibration can accurately measure static torque and torque at low speeds.
2. No slip ring
The torque measurement is realized by the output signal of the non-contact magneto-electric detector, so this instrument can measure high-speed torque that is impossible for other instruments.
3.High accuracy and good stability
The torsion shaft is made of high-grade alloy material with excellent elasticity and minimal hysteresis effect, so it has high sensitivity, small residual deformation, and stable and reliable reading.
4. Simple and convenient operation
The instrument is compatible with TR-1, which can automatically measure and directly read the torque, speed and power. After setting data storage, it can be directly measured each time it is turned on.
Third, the main technical parameters:
1. The sensor is suitable for working at ambient temperature 0-55 ° C and relative temperature not exceeding 90%.
2. The applicable speed range and coupling weight of the sensor (see the table below):
· M ） Rated torque ( N · M )
分） Speed range (rev / min)
Weight of single coupling ( <= kg)
3. Couplings, pads, test plates, etc. required by the sensor According to user requirements, the company can process them.
4. Total system error:
(1) Static calibration accuracy: At the same ambient temperature where the sensor coefficient is calibrated (corrected according to the temperature coefficient when it is not the same), the static calibration error should not exceed ± 0.2%.
(2) In the range of rated speed, when the sleeve is fixed at any position, the change of the torque measurement reading at different speeds should not be greater than ± 0.2%.
(3) When the rotating shaft of the sensor rotates, the reading error should not exceed ± 0.2% when the intermediate sleeve is at different positions; or the rotating error of the intermediate sleeve (start the drive motor), and the reading error should not exceed ± 0.2% when the shaft is at different positions.
5. Measurement accuracy: The sensor cooperates with TR-1, and its measurement error does not exceed ± 0.5%.
6. Maximum allowable torque: 120% of rated value.
7. Output voltage signal amplitude: not less than 0.7V effective value.
8. The external dimensions are shown in Figure 2.
9, working time: continuous operation.
× 42 × 8 8-48 × 42 × 8
× 90 × 14 10-100 × 90 × 14
1. The sensor must be installed firmly to prevent vibration during work.
2. The installation position of the sensor is shown in Figures 3 and 4.
3. The concentricity of the sensor installation should not be greater than 0.1mm, otherwise, the measurement accuracy of the instrument cannot be easily guaranteed.
4. The coupling on the load side of the sensor should be easily disengaged for zero point adjustment.
5. Because the speed signal of the sensor is the algebraic sum of the speed of the shaft and the speed of the sensor sleeve, when the drive motor on the sensor is turned on, the speed of the torque shaft should be equal to the difference between the reading of the instrument and the speed of the sensor motor.
6, the sensor should be used to avoid vibration.
7. Changes in ambient temperature will directly affect the measurement accuracy of the instrument. When the measurement accuracy is not high, the calibration coefficient may not be modified when the temperature difference is ± 10 ° C relative to the calibration temperature of the sensor. If the ambient temperature exceeds this range, It is necessary to modify the calibrated coefficient value of the sensor, that is, to use the TR-1 coefficient after correction to ensure the test accuracy of the device. The correction of the temperature coefficient is calculated according to the following formula:
Xt = Xto [1 + εG (t-to)]
In the formula: Xt --- the sensor coefficient when the temperature is t.
Xto ---- The sensor coefficient calibrated when the temperature is to (that is, the temperature coefficient of the sensor on the nameplate).
t ----- The actual ambient temperature ℃ during measurement.
to ---- The ambient temperature ℃ when the sensor coefficient is calibrated.
εG ---- temperature coefficient of shear elastic modulus G, its value is taken here as --0.027%.
For example: The calibration coefficient of the sensor when it leaves the factory is 7215. It is calibrated at 10 ° C. Now it is used at 36 ° C. The correction coefficient is: Xt = 7215 × (1-0.027% × 26 ° C) = 7164
That is, the calibration coefficient of the sensor is corrected to 7164, and the TR-1 coefficient is set to 7164 when used. If the ambient temperature is still 10 ° C, the coefficient is still 7215.
8. Operation steps:
(1) Connect the sensor to the tested power transmission shaft and load block diagram sequence and the above 1-4 installation and connection firmly.
(2) Connect the signal output line to TR-1, and set the calibration coefficient of TR-1 according to the coefficient value indicated on the sensor nameplate.
(3) Disengage the load-side coupling, start the machine under test, and adjust the zero point of TR-1. If the amplitude of the output voltage signal is lower than 0.7V due to the low speed, start the drive motor on the sensor and make Its direction of rotation is opposite to the direction of rotation of the measuring shaft, but the speed at this time is obtained in accordance with Article 5.
(4) The coupling can be connected for measurement.
9. Maintenance requirements:
(1) The sensor must be carefully debugged and compensated before it leaves the factory. Do not disassemble it to avoid losing accuracy.
(2) After using the sensor for a period of time, if it needs to be calibrated and maintained, please return to our factory and recalibrate.
(3) The sensor should be avoided from use and storage in severe vibration and high temperature and humidity environment.
(4) The packaging and transportation of sensors shall be implemented in accordance with the "Measures for Packaging and Transportation of Precision Instruments".