FR2514500A1 - METHOD AND APPARATUS FOR NON-CONTACT TORQUE MEASUREMENT - Google Patents

Abstract

CONTACTLESS TORQUE METHOD AND APPARATUS. NOTCH PATTERNS 34, 36 ARE PROVIDED AROUND THE SHAFT, AND SENSORS A, B, C, D ARE PLACED IN PAIRS NEAR EACH PATTERN. THE TORSION OF THE SHAFT PRODUCES AN EXHAUST IN THE SIGNALS EMITTED BY THE SENSORS DURING ROTATION, AND THIS DEPHASING IS TRANSLATED INTO TORQUE VALUES. THE ARRANGEMENT OF THE SENSORS ALLOWS THE INFLUENCE OF VERTICAL AND HORIZONTAL MOVEMENTS OF THE SHAFT TO BE ELIMINATED.

Description

14500

  The present invention relates to a method and a

  torque measuring device and it has a more specific

  and a non-contact torque measuring method and apparatus in a shaft connecting driving and driven mechanism. By measuring the torque of a rotating shaft of a

  coupling between driving equipment and

  born, it is possible to calculate the performance of the equipment

  On the move Such results can also be

  be used to detect power surges in a

  equipment and to notify operators of changes

  Necessary conditions of operating conditions before such power surges can damage the driving equipment or the equipment being driven. In addition, these results can be used to determine when maintenance is needed. In the prior art, attempts have been made to measure the

  couple by different processes Thus a proposal was proposed

  in which an additional sleeve is mounted on the

  coupling to compensate for a movement of the latter Well

  that a satisfactory measure of the couple has been obtained, the man-

  additional cost tends to increase the price of the

  and increase its weight also.

  of the Stress Measurement Gauges associated with

  collectors but these tend to wear out quickly

  and require frequent replacement if you want

  obtain specific measures It was also proposed to

  a signal transmitter inside the coupling.

  However, as the couplings do not all work

  in an ideal environment, issuers frequently fall

  The present invention relates to a method and a device for measuring torque which results in a downtime of the equipment and disassembly of the coupling to replace the transmitter.

  do not increase the cost or weight of the

  actually said and that do not require frequent maintenance

2514 Q 00

of the electronic part.

  In accordance with the present invention, the relationship

  phase of the signals produced by sensors A, B, C and D is compared and processed by an electronic circuit and the resulting signal generated is the true torque transmitted via the coupling. These signals produced by the sensors contain unwanted phase shifts caused by movement of the coupling axis in either or both horizontal and vertical directions To eliminate these error signals caused by the

  movement of the coupling pin, the circuit compensates for

  horizontal movement by determining the

  crossing point at zero of the tensions generated in each

  sensor to compensate for a vertical movement, the circuit automatically ensures the cancellation of the phase shift generated in the sensors A or B by the delay phase produced in the sensors C or C mounted in positions diametrically opposed to the detectors A and B Both horizontal and vertical compensations for the movement of the coupling pin are therefore made

  automatically without having to

  corrective signals or to modify the detection circuit.

  Other advantages and characteristics of the

  will be highlighted later in the description of the

  tion, given by way of nonlimiting example with reference to the appended drawings in which:

  Fig 1 is a side elevation view of

  and in section of a coupling using the process

  and the torque measuring apparatus according to the invention.

  FIG. 2 is a block diagram of the circuit of

according to the invention.

  Fig 3 is a diagram of a detection circuit

according to the invention.

  FIG. 4 is a timing diagram of the circuit according to the invention, and

  Fig. 5 is a graphical representation of the

  baked automatic compensation of the movement of the axis of ac-

couplement.

  In FIG. 1, a coupler has been designated by

  consisting of hubs 12 and 14 having gear teeth 16 and 18 directed outwardly Hubs

  12 and 14 are mounted on a driving shaft 20 and a measuring shaft

  born 22 by conventional means such as key grooves

  The gear teeth 16 and 18, outwardly oriented, of the hubs 12 and 14 engaged with the inwardly extending gear teeth 24, 26, the sleeves 28 and 30 are shown in FIG. Sleeves 28 and 30 are coupled by means of a spacer 32 by conventional means, such as bolts, not shown.

  the spacer 32 disposed between the sleeves 28 and 30 is di-

  exactly proportional to the transmitted torque of the

  20 to the driven shaft 22 Error signals generated

  by a movement of the axis of the tree in a

  rice and / or vertical are also manifest as torque signals and must be eliminated to obtain a

true torque value.

  As shown in Figure 1, two reasons for

  symmetrical bushings 34 and 36 are machined in the surface of the spacer 32 and extend circumferentially around

  the outer surface of the spacer 32 The reasons for

  ticks are composed of 65 teeth distributed over a primary circle.

mitive 228.6 mm in diameter.

  Four passive magnetic sensors A, B, C and D

  are mounted in an essentially horizontal plane and

  The sensors are spaced approximately 1.5 mm from the notch pattern. Any suitable assembly, for example a cylinder, may be provided for

  wrap the outer side of the spacer 32.

  A rotation of the spacer 32 makes the models

  notches 34 and 36 generate a current signal al-

  in passive magnetic sensors A, B, C and

  D The signals from each sensor are boosted by an amplifier

, 14500

  FIG. 38, FIG. 3. It is apparent that each sensor has a capture circuit 40 identical to that indicated for A.

  in FIG. 3 The amplified signal is transmitted to a comparator

  The comparator 42 produces at its output a square waveform signal which

  switches to the same crossing point as the signal

  It is obvious that the signals of the sensors B, C and D are amplified and shaped in the same way. The square waveform signal is then applied to the diode D1 where its part basic is

  and the output voltage is reduced to an inde-

  lower by the voltage divider R 1, R 2

  buffers 50 to 53 providing signal conditioning for protecting and isolating the low level logic circuits 54, 44, 55 and 46 of the inverting stations 54 and 55 of the

  A and C are used to change the phase of the corresponding signals.

  as shown in the timing diagram of the

  Figure 4 Signals from A sensor circuits

  and B are combined in a NAND door.

  from the sensor circuits C and D are combined

  born in a NAND gate 46 The combined signals from sensors A and B and C and D are applied to a gate

  NAND-48 The output signal from gate 48 has been

  in the timing diagram before a vertical shift

  The same output signal has been shown as signal E1 in FIG. 4 after a vertical offset has occurred at the driven end, or leading. , of the tree

  32 forming the spacer It should be noted that the average value-

  ne of the waveform in E is equal to the average value of

  the El waveform for 360 degrees rotating electric

  tion, that is to say for a complete tooth We can see therefore that the error generated by a vertical movement

  from the shaft to the driven end has been canceled or eliminated.

  This is also true for a vertical movement of

  at the leading end is obtained at the exit of the door

  te 48 a signal of which any component created by a movement

  horizontal or vertical axis of the coupling

  This conversion can be performed in a signal averaging circuit such as that shown in FIG.

49 in Figure 3.

  The signals are then sent to a comparator

  analog meter 60 which compares it to a reference in

  continuous stream 61, the result being sent to the

  file 62 which gives directly the cut of the recycling

  gain 62 and 4 zero 63 being provided.

  A movement of the coupling pin in a di-

  horizontal rection causes a variation in the magnitude of the generated AC signal, as shown in FIG. 5 These amplitude variations would vary the phase of the output signal if compensation was not performed Only the zero crossing point the alternating current signal remains the same since the operating frequency remains the mt e The voltage comparator 42, Fig 3, acts as a zero crossing detector and as a pulse converter for transforming the AC signal produced by the sensor into a signal of

  square waveform directly proportional to the frequency

  this or angular rotation of the spacer 32.

  With reference to FIG. 5, a vertical movement

  ascending caliper of the shaft 20 causes a phase shift of the signal

  generated in sensor A in the positive direction or in advance

  this for a rotation of the shaft in the direction of clockwise Conversely the identical signal generated in the sensor B mounted in a position diametrically opposed to that of the sensor A is out of phase in the negative direction or

  delay This phase shift in the sensor A is accurate-

  equal to the delay phase in the C sensor and,

  that these two signals are combined in the NAND gate 48, the positive and negative phase-shifts cancel each other out.

  also occurs between sensors B and D when the

  22 goes up or down in the vertical direction.

  As a result, the unwanted error caused by the vertical movement of the axis is eliminated and the true torque signal remains directly proportional to the shaft twist.

Claims (4)

  1 Torque measuring device of a rotary shaft   characterized in that: (a) a plurality of notch patterns (34, 36) are formed on the shaft, (b) a plurality of sensors (ABCD) are mounted in a horizontal plane and in close proximity and on opposite sides said notch pattern with respect to the axis of said shaft,   (c) said sensors are arranged for detecting   a signal resulting from a rotation of the patterns of still   on said shaft, (d) a circuit is provided for analyzing the signals detected by said sensors and for transforming said signals into a signal representing the torque applied to the shaft, and (e) means are provided for displaying the signal   of torque as a direct measure of the couple.   2 A method of effectively compensating for   the axis of the shaft in a horizontal direction   characterized in that the crossing point is detected at zero.   ro of the AC signal produced in the capacitor tor.   3 Method for accurately compensating for   the axis of a tree in the vertical direction,   characterized by canceling the out-of-phase signal occurs   on one side of the coupling using the same phase-shifted signal occurring in the other side of the coupling,   that is to say at both ends of the spacer brace plement.   Apparatus according to claim 1, characterized   in that two notch patterns are provided (34, 36)   consisting of several teeth machined in said shaft.   Method for determining the torque of a   rotating shaft, characterized in that it comprises the   following steps: (a) machining a plurality of slot patterns in the shaft,   (b) detect a signal generated by rotation   said patterns using passive sensors, and (c) analyzing said signal to transform it   in a measure of the torque applied to the shaft.