DD141202A1 - DEVICE FOR MEASURING THE TORQUE AND THUS ASSOCIATED SIZES OF SHAFT CONNECTIONS - Google Patents

Abstract

The invention relates to a device for measuring the torque on shaft lines and related variables such as shaft power and wave energy and shaft speed and is particularly intended for use on the propeller shafts of ships, but can also be used on other waves. The aim of the invention is a device that allows continuous monitoring of the torque supplied by drive systems, so that overloading of the same can be avoided. The object of the invention is to provide a device for the digital measurement of torque, shaft power and wave energy, which reaches and exceeds the best known devices in accuracy from the working principle and in which no institution-specific customization for pulse generator or mark carrier and their scanning are necessary , It is solved by the use of zero pulse incremental rotary encoders which are driven by the shaft via mechanical means and whose count pulse outputs after digital processing using gate and counter circuits provide measurements of the torque, shaft power and wave energy.

Description

** I *** gas

invention description

a) Title:

Device for measuring the torque and related quantities of waveguides

b) Field of application of the invention:

The invention relates to a device for measuring the torque on shaft lines and related variables such as shaft power and wave energy and shaft speed and is particularly intended for use on the propeller shafts of ships, but can also be used on other waves,

c) Characteristic of the known technical solutions

Numerous solutions for measuring the torque of rotating shafts are known, the most important of which can be classified according to the following overview:

Devices for measuring the torque at rotating_shafts - overview

A) Measurement of the torque-proportional surface strain by means of strain gauges, strings o. A _e

B) Measurement of the torque-influenced magnetic properties

10 1

C) Measurement of the torsion angle, the two spaced apart by a length of 1 shaft cross-sections against each other take torque proportional

C.) with mark-carrying or pulse-forming means which are rigidly connected to the shaft and which rotate coaxially with the shaft

Cp) with mark-bearing or pulse-forming means, which are connected in addition to the shaft running and with this gear or traction mechanism so that its rotation angle is a constant multiple of the shaft rotation angle

is' ...

Here, only the facilities which are to be classified in the group Cp according to the above overview should be considered. "Those institutions, which are to be classified in the group Ou according to the above overview, use in the processing of the signals formed by means of the brand-carrying or impulse-forming means Part similar arrangements as those after Cp, which also takes into account «,

The invention described below is to be classified in the group Cp according to the above overview, so that reference is also made mainly to devices having the characteristics of Co. Such devices are described in the

- United States Patent 3,640,131

- US Pat. No. 3,081,624

- Brochure material of the company Bordmeßtechnik Hoppe, Hamburg

"Viewing electroniser, slip-ring-free power, torque and tachometer for propeller drives" (hereinafter referred to as Hoppe system)

With regard to the signal processing to be classified in the group C, according to the above overview device, described in DDR-WP 124678, also considered v / earth.

The aforementioned 'United States patent 3081624 facilities, the Hoppe plant and the DDR-YO facility. 124678 have the laughing thing in common that donor devices or, brand-bearing means and the latter belonging scanning devices are used, which are specially manufactured for the respective device with high precision, which in particular "very costly and thus disadvantageous in the usual for measuring systems on propeller shafts small numbers Although the device according to US Pat. No. 3,640,131 does not have this disadvantage, since optical or other tachogenerators known from other applications also find application, because of the low resolution of these encoders, a phase measurement by impulse blanking must be carried out This results in two measuring errors: first, the measurement error of the individual measurement increases with the rotational speed, and, secondly, relatively complicated additional means are necessary in order to obtain the independence from the torque required to measure the torque to reach

The Hoppe system works purely analog and does not offer the possibility in modern plants to be required to the computer port _β When you make here analog signal processing, temperature changes and aging components of fehlervergrößerndem influence · "

In the device according to DDR-WP 124678 and similar operating devices must be in order to achieve a small error that exploit the properties of the averaging random signals d _e h., It is necessary to achieve the greatest possible number of samples per revolution, wherein in each Scanning as many pulses (for a given torque) must be detected «. If the single scan · a certain statistical error, and r is the number of samples used for averaging, the error of this average by a factor of 1 / ^ P is smaller than that of the individual measurement. So you try, once by winning a large number of

'"- ⁴ - 210 180

Pulses in the individual sampling to keep the statistical error of the single measurement small (this is used in DDR-WP 124678 a ImpulsTervielfachung) and the second, the number of samples (averages) as possible to make large, in which one with the available measuring time The realization of the requirement to provide measured values with a small error in short times leads to the requirement to make the division of the mark-carrying means or the pulse spacing (in radians) as small as possible ". However, in the case of the device according to GDR -WP 124678 and similar operating devices limited by the uniqueness requirement, according to which the brand or pulse spacing must be greater than the largest occurring in the measurement angle of rotation of the brand-carrying or pulse-forming means against each other. «This limits the resolution or requires very large measuring times, so here from the measuring principle establishes a limitation is _o by kom mt that the single scan of relatively coarse marks in relation to the twist angle a large error (caused z. B) by variations in the receiver sensitivity or the trigger thresholds).

d) Object of the invention

The aim of the invention is a device that allows continuous monitoring of the torque supplied by propulsion systems, so that the same overloads can be avoided and the necessary to optimize the operation, for the assessment and economic comparison of systems sizes Weilerleistung and wave energy and also a signal for the Shaft speed delivers and this in digital and in a suitable for further processing by computer form «

e) Presentation of the essence of the invention

The object of the invention is to provide a device for the digital measurement of torque, shaft power and wave energy, the best of the working principle

known devices reach or exceed accuracy and in which no device-specific customization for pulse generator or brand carrier and their Ab tation are necessary »

This object is achieved in that the pulse generator for the rotation angle at each of the two wave cross sections whose torsion is to be measured against each other, as incremental rotary encoder with 'zero pulse known donors, as for way »and. Angle measurements are made on machine tools, find use, which are located next to the shaft and are driven by this phase-locked by mechanical means, the output signals of the encoder, d. h, the Zählimpulsfolgen (even after a possible multiplication) and the zero pulses are given to counter, each of which after a certain number of D run count pulses a pulse D «. or «Dp and reset by the zero pulses of the respective encoder in an initial position (synchronization), these pulses D ₁ , and Dp act so that opened with the pulse D ^ a first gate and with the pulse D ₂ this first Tor is closed, and at the input of this first gate the (possibly multiplied) counts of one of the donors are laid «It is assumed that when the shaft torque is zero, the encoders are adjusted so that their zero pulses occur simultaneously or one other known starting position is taken. If the zero impulses coincide at zero torque, ie they occur simultaneously at M = O, a number from the first port through an opening and closing operation will occur

K ν n _{r in} m = __ £ _, y _w (Equation 1)

2.x n _w

Pulses which are proportional to the shaft torsion angle and thus to the shaft torque.

In the above equation

K - encoder constant, ie the number of pulses emitted by the rotary encoder * per revolution · from a counting track. The inverse 2 Jt Ai is called resolution.

ν - Multiplication Factor Multiplication of the counts is possible by using two out of phase counting tracks or in some other known way *

- Torque proportional to the angle of rotation of the two cross sections against each other

It is

Vw = f ~ TT (Equation 2)

M - too. Measuring torque of the shaft

G - sliding modulus, material constant of the Y / ellenmaterials

- polar moment of inertia of the shaft

- Distance of the measuring locations

- Ratio determined by the mechanical coupling between the shaft and encoder donor speed n _ß and shaft speed n ^ _e It is also Ü =

It is f _w the angle of rotation of both cross sections of the shaft against each other and if q the associated torque-induced rotation of both donors against each other *

The further processing of the pulses emerging from the first gate is carried out in arrangements which are together with the previously described subject matter of the invention.

In order to form a torque-proportional, dispensable value, according to the invention, the summation of the pulses expiring from the mentioned first gate takes place during a number of ρ encoder revolutions in a first counter.

For measuring and signaling the ρ encoder revolutions serve count stages (p-divisor), to which the Uullimpulse one of the encoders are given and emit after each ρ UuIlimpulsen an output pulse. With the occurrence of an impulse of one of the encoders, the summation is started in the previously deleted first counter, and after ρ Geberura "rotations are completed", after completion of this accumulation, the state of the first counter is then:

% ^s fir ^ ^V w · ^Ü · ¹ T- P '(Equation 3 * 1)

or

• R-2 2

% "2ΊΓ D ^Y * ^Ü * ^p · fw (Equation 3" 2)

In this case, the factor ν K / D characterizes the opening and closing operations of the first gate occurring per encoder revolution. "The counter reading which occurs in the first counter at the end of the summation process and can be further processed is proportional to the torque.

In order to form a 7 / ertes proportional to the shaft power according to the invention the pulse train leaving the first gate is applied to a second counter via a second gate and summed up in this second «second gate is supplied after deletion of the second counter by a timer circuit known per se Pulse for the time TT ₁ open and after the time ¹ T ^ closed again, Uach the expiration of the time T * is the number of pulses entered into the second counter

tr ,, ν TC

% -zr- . ν. U » _w .T, en _Q ¹ ^ p (Equation 4 * 1)

- 8-210 180

The product *% .n ^ .VK / D is equal to the number of bursts of pulses exiting the first port during the time <T ₁

 ".2 2

^ L ⁼ ""p'ör- ^ 'Πί * φ γ, ^η ψ (Equation 4.2)

and this count is proportional to the shaft power, the measurement is thus also realized.

Finally, to obtain a value for the wave energy. According to the invention, the expiring from the first gate pulses are summed in a third counter. Is the time 1 "since the zero position of this third counter passed ο, then the content of this third counter

K ² v ² Ü ²

Np = -rr '-, - ν''-{/> «n _w . TO (Equation 5)

JC /C. JL D / Vv · c *

and thus the wave energy transmitted in the time T ₂ proportional.

f) embodiment

The solutions according to the invention will now be explained in more detail by means of embodiments in conjunction with drawings. The drawings show

Pig »1: A first device for measuring and displaying values proportional to the torque, the shaft power and the wave energy as well as the shaft speed

Pig. 2: Arrangement of the rotary encoder in connection with the shaft. ,

Pig «3s Example of the output signals of a rotary encoder

Pig. 4: Representation of a known method of pulse multiplication

FIG. 5: Representation of the pulse trains occurring in the device according to Pig · 1

Pig * 6: Section of another device for measuring shaft torque, shaft power and wave energy

Fig. 2 shows the arrangement of the two rotary encoder 1 used on the shaft «In the example chosen, the rotors of the rotary encoder 1.1 and 1.2, the housing are fixed, driven by gears 2 and 3 of the shaft. The gear ratio is ü sd | / a «= η« / η ^ _β The drive of the encoders through the shaft can also be achieved by means of a traction mechanism, eg a belt drive. B. timing belt or otherwise possible.

The output signals of these identical rotary encoder shows for the encoder 1.1 schematically Pig. 3 "The zero pulse IL occurs here once per revolution. The counts of a count track occur K times per revolution. K is the encoder constant. In Fig. 3, K - 50 has been selected. Values of K = 1000, K = 2000, K = 2500 or even-K = 5000 are common for such encoders. It should be noted here that it is also possible to use encoders which, in addition to the counting pulse train, instead of the zero pulse train (one pulse per revolution ) provide another pulse train with more than one pulse per revolution. If there are q pulses per revolution in this lane, then the condition q <c ν K / D must be fulfilled because of the uniqueness required. The zero pulses are used only for synchronization and to set the zero point of the arrangement «

Fig. 4 shows an example of a otherwise known type of multiplication of the counts to explain this term used. The encoder supplies two pulse sequences A and B offset by a quarter-period. By differentiating the edges of both signals and combining, a pulse train with four times the frequency is produced. This type of multiplication is described among other possibilities in the literature and is not the subject of the invention.

Pig. 1 shows the device according to the invention for measuring shaft torque, shaft power and shaft energy. The two counting pulse outputs A ₁ and B- or JU and Bp of the rotary encoder -1.1 and 1.2, in the example chosen Pig. may be connected to the inputs of the multiplier circuits 5e1 and 5x2, in which z. For example, FIG. 4 shows the multiplication of the pulse sequences. The outputs of the multiplier circuits 5 * 1 and 5 * 2 are connected to the inputs of divider circuits 6.1 and 6.2. These deliver every time when a certain number of D counts the pulse trains ZV 1 and ZV 2 has entered the divider, an output pulse D. bzY /. Dp «By the zero pulse of the encoder, ie by the pulses IL or N _? Preferably, these divider circuits are synchronized by zeroing them. For this purpose usable circuits are known from the literature. To be able to perform the synchronization simply, the factor (K ν / D) should be integer, so that the synchronizing zero pulse coincides with a D ₁ or Dp pulse «

The output pulse D _{1 of} the divider 6.1 is connected to the ES-Plip-Plop 7, composed of the two KAM) -Glieder T.1 and 7 * 2, so that when the pulse D _{1 occurs} with the first 'gate 8 connected Plip ~ Plop output at which the signal P occurs releases this gate. The output pulse Dp of the divider 6 * 2 then sets the plip-plop again so that its output signal P blocks the first gate 8 again. The first gate 8 is formed by an AND element. If the output signal of the flip-flop 7P = H, the possibly multiplied counting pulses here of the encoder 1.1 can pass the first gate 8. Pur P = T, the first gate 8 is blocked for the pulse train ZV 1.

This also explains Pig. 5. In Pig «5, ZV 1 represents the counting pulse sequence of the first encoder 1.1 after the multiplication. N- is the zero pulse of the first rotary encoder 1.1, which occurs once per revolution.

2 10 180

With N ₁ , the pulse D ₁ occurs (synchronization). For the example chosen here with D = 10, D ₁ occurs after every 10 further pulses of the pulse sequence ZV 1, ZV 2 is the counting pulse sequence of the second encoder 1.2 after the multiplication. Again, D ~ occurs with the zero pulse JL (synchronization). After every D = 10 pulses of the pulse sequence ZV 2, a pulse Dp occurs. D. now sets the RS-flip-flop 7, the signal F = H, so that the first port 8 is opened. The pulses of the pulse train ZV 1 can then pass this gate. With the appearance of Dp F = T is set and thus the first gate 8 closed again until the arrival of a new D ₁ pulse. In the example according to FIG. 5, five pulses thus pass through the gate 8 in each opening-closing cycle. These five pulses are a measure of the rotation of both encoders relative to one another and thus to the angle of rotation of the shaft, including the shaft torque. We now refer back to Fig. 1.

The output pulses of the first gate 8 form the pulse train E. The output of the first gate 8 is connected to the counting input C of the first counter 11, which detects the shaft torque proportional value. With the occurrence of a specific zero pulse N _{1 of} the rotary encoder 1.1, the counter is reset by this pulse acting on the zero pulse divider 9 at the reset (R) input. Then the expiring from the gate 8 pulse train enters this first counter 11 and the pulses are summed up. After a specified by the NuIlimpulsteiler 9 number of ρ zero pulses N ₁ , a pulse occurs, which causes the loading of the then existing counter content N _M in the memory 15.1 and then resets the first counter 11 again. Immediately thereafter, the new count begins. The value N 1 then in memory is proportional to the shaft torque, as shown in equation 3 * 2. The display unit 16.1 connected to the memory can display this value.

10 1

The output pulse train E of the first port 8 is further switched to a second gate 10, which has been formed as an AND gate. At the second input of this AND gate 10 is supplied by the timer circuit 18 pulse T ₁ , which assumes for a time ^ * Η potential and so the second gate 10 for the time / ^. opens. Purely the time ¹ ^ - the pulse train E emerging from the first port 8 can enter the second counter 12, and the pulses are summed up in this second counter 12. Each expiration of / ^ - the pulse T ₁ briefly goes to T-potential, thus causing the loading of the then reached counter reading Nr in the memory 15 · 2 and (delayed) resetting the counter 12, which then immediately with T ₁ = H again takes the count. The counter reading Er accumulated in the counter after the expiration of 'ζ ₁ is given by Equation 4.2 and is proportional to the shaft power. The 'display of this value can be done using the display unit 16.2 *

The output pulse train E of the first port 8 is further fed to the input of the third counter 13. If the time T has passed since the zeroing of this counter, the content of this counter is given by Equation 5 and thus proportional to the wave energy. The counter 13 is expediently composed of two successive stages. The first stage 13.1 is an electronic counter, which supplies a pulse to the electromechanical counting stages 13 * 2 respectively at overflow. The status of the electromechanical counter stages is displayed. This ensures that even with a momentary power failure, the value integrated over a long time for the wave energy was retained

Finally, another fourth counter 14 may be used, in which via a gate 17, realized by an AND gate, the counting pulses ZV 1 or ZV 2, here ZV 1, can shrink. The gate 17 is opened and closed by a pulse T ^ generated by the timer circuit for a time χ ₀ .

After this time has elapsed " is the meter reading reached

¹¹ W

and thus the shaft speed proportional. Instead of the pulses ZV 1 or ZV 2 can be switched to the gate and the pulses N .. or H ₂ , A ₁ or Ap, IL or Bp; always results after the time ^ p one of the shaft speed .proportional meter reading.

After expiration of ^ p T ₂ goes T-potential for a short time, thus causing the loading of the count N in the memory and the reset of the fourth counter 14. Immediately thereafter, the summation begins again. The speed N of the shaft proportional value N can be brought to the display unit 16.4 to the display.

The memories 16.I, 16 "2 and 16.4 and the counting stages 13.2 have parallel outputs, which have been indicated here by one line in each case (20.W, 20.L, 20.M and 20" n). These lines lead to other units, eg. As a computer, a controller or remote displays, etc., so that are available for these units digital input signals.

The above-described embodiment of the solution according to the invention also has the disadvantage that at torques of the order of zero by tolerances or Justierfehler the output pulse of the second divider 6.2, the pulse D ₂ , before the output pulse of the first divider, the pulse D ₁ , can occur , The counter readings that occur can not · be evaluated correctly. To avoid this error, an offset S is used. For this purpose, the encoders are rotated relative to one another at a torque of zero (M = 0) so that the pulse D ₁ always occurs safely in front of the pulse Dp when all tolerances are observed. It is assumed that this offset shift is so large that, on average, m = S pulses occur between the pulses D ₁ and Dp, where S is an integer positive number.

-η- 2 10 130

This offset value S must, um. to get proper displays, then subtracted again. To realize this, for the first counter 11, for the second counter 12 * and for the third counter. It uses 13 counts of forward and reverse counting backwards when pulses appear at the DV inputs, and backwards when pulses occur at the CR inputs. Pig. 6 shows a section of the arrangement used with offset correction. The elements 7 * 1, 7.2, 8, 9 and 10 correspond to the arrangement according to Mg. 1. Purely the counters 11, 12 and 13 were used in front-to-back counters. In addition to Pig. 1, the gate 22, the R-S-Plip-Plop consisting of the NAND gates 21 * 1 and 21.2, the counter 19 and the MD gate 23 * were inserted.

The circuit now works so that with the occurrence of D ₁ = pulse, the RS-Plip-Plop 7 «1/7 · 2 is set so that the gate 8 is opened. Until the arrival of the gate 8 blocking pulse D "runs the count in the individual counters as described above.

With the appearance of Dp, the first gate 8 is blocked, opened by switching the RS-Plip-Plop 21.1 / 21.2 the gate 22 through which now the Zählimpulsfolge ZV 1 on the Rückwärtszähleingänge CR of the individual counters 11, 12 and 13 runs. At the same time the counter 19 is released, and this also counts the ZV 1 pulses. During this phase, the offset subtraction occurs. The counter 19, after the number of pulses of the Zählimpulsfolge ZV 1 corresponding to the offset value S has entered it, on the output side a T-pulse, which resets the RS-Plip-Plop 21.1 / 21.2, whereby the gate 22 is locked and the Offsetsubttraktion is completed. In order to do this _correctly , the numbers defined above must satisfy the condition D ^ m (\ _ia3 ;) + S to ensure uniqueness. Preferably, the counter 19 can be executed programmable to compensate for tolerances of the setting electronically.

10 1!

The specific advantages of the solution according to the invention are:

1. The brand distance of the encoder may, measured as an angle, be smaller than the largest occurring angle of rotation of the donors against each other, without the requirement for uniqueness is violated - so that the resolution of the measuring device by the possible finer subdivision of the scale over known means is significantly increased ·

The reason for this is that in the inventive solution in contrast to those described in the DDR-WP 124678 and related devices in which the pulses of the encoder are used both for triggering the measurement and for synchronization, here the Zählimpulsfolgen for the measurement and the extra hull pulse can be used for synchronization *

It also follows, as already mentioned, that instead of the frequency pulse track (one pulse per revolution), it is also possible to use a track from which more than one pulse per revolution is taken. The angular distance of these pulses must now be greater than the largest angle of rotation of both donors against each other, with any offset shifts must be considered.

2. Furthermore, many samples are obtained by the high resolution in short times. The subsequent accumulation in the counters represents an averaging of the individual values. The high number of abbreviations reduces the statistical error proportion considerably. In torque measurement, in order to form the torque-proportional value to be displayed, K ν ρ / D samples are added in the first counter, each of which has a statistical error on its own «

The statistical error of the final sum is, according to the known laws of statistics, smaller by a factor of 1 / KvKp / D'than that of the single pulse sequence.

ΊΟ 1

Thus, the measurement of the torque is realized with high accuracy. The same applies to the measurement of shaft power and wave energy.

3. In the device according to the invention donors can be used, which are industrially manufactured in high precision and in large quantities. This simplifies the manufacture of the device and reduces costs.

Claims (5)

invention claims 1. A device for measuring torques and associated quantities of waveguides, wherein the torsional or torsional angle, the two torque cross-sections spaced apart by a certain length against each other take torque proportional, using label-bearing and rotational angle dependent impulse forming means, called short donors, is measured, which run alongside the shaft and are connected thereto by gear or other gear so that their angle of rotation is a constant multiple of the shaft twisting angle at the respective cross section and the sender have a defined initial position with respect to each other at a torque of UuIl, characterized in that as encoder incremental rotary encoder with zero pulse (1.1 and 1.2) are used, the Zählimpulsausgänge (A. and B ₁ or Ap and Bp) even after an additional linkage of the output pulses of each encoder to divider (6.1 and 6.2) are given , which in each case emit an output pulse (D. and Dp) according to a number of pulses that have run in the same way for both divisors, whereby the dividers are represented by the zero pulses (N ₁ or ITp) of the encoders (1.1 or 1.2) by placing them in a defined position , are preferably synchronized by zeroing or clearing, and further the outputs of the divider (6.1 or 6.2) are switched so that one pulse with a first gate (8) is opened and closed with the other pulse of this first gate (8) and at the input of this first gate (8), the Zählimpfolge one of the encoder is applied, which may pass in dependence on the output signals of the divider (6.1 or 6.2) this gate or not and the output of this first To Res is summed during a given, determined by a UuIlimpulsteiler (9) number of zero pulses of the encoder in a first counter and that the first door (8) exiting pulse train (E) is given over other gates on more counting members. 2. Device according to item 1, characterized in that the output of the first gate (8) with a second gate (10) is connected, which is opened by a timer circuit (18) supplied pulse (T ₁ ) for a certain time and the output of this second gate (10) is connected to the forward count input of a second counter (12). 3. Device according to item 1, characterized in that the output pulse sequence of the first gate (8) is given to a third counter (13). ' 4 * Device according to item 1, characterized in that encoders are used which have, in addition to or to the Zählpululsspureη instead of the zero pulse track with one pulse per encoder revolution such an additional track that delivers more than one pulse per encoder revolution. 5 · Equipment according to items 1, 2 and 3 ,. characterized in that the encoders are adjusted so that even at zero torque, a number of pulses pass through the first port (8), the first counter (11), the second counter (12) and the third counter ( 13) are designed as forward / backward counters and that these counters count forward from the first gate (8) and also passing via intermediate links on the counter impulses and after completion of a single scan for a programmable by another counter (19 ), the number of counts counted backwards being equal to that which occurs in the individual samples on average at zero torque.