JP3129352B2 - Torsion angle displacement measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torsional angle measuring device applied to a shaft system of a rotary machine.

[0002]

2. Description of the Related Art FIG.
This will be described below with reference to (b). FIG. 2A is an explanatory diagram of a detection end which is disposed on a shaft system of a turbine generator and constitutes a conventional device.

[0003] As shown in FIG. 2A, the turbine generator includes a high-pressure turbine rotor 1a and a low-pressure turbine rotor 1a.
b, a generator rotor 2 and a shaft 3 connecting them, and gears 4a and 4b having the same number of teeth are installed on a shaft 3 system connecting the rotors 1a, 1b and 2 together.

On the stationary side facing the teeth of the gears 4a, 4b, non-contact type electromagnetic rotary pulse detectors 5a, 5b, which are the above-mentioned detection ends, are installed.
There detection signal P _a, P _b to be output is input to a torsion angle displacement measurement apparatus shown in FIG. 2 (b).

[0005] The torsion angle displacement measuring device shown in FIG.
The high-frequency reference signal oscillator 20 comprises a high-frequency reference signal oscillator 20, a phase difference counter 21, a speed counter 22, a divider 23, and a D / A converter 24. The high-frequency reference signal oscillator 20 always oscillates at a constant frequency and outputs a signal of that frequency. Output.

The above-mentioned non-contact type electromagnetic rotation pulse detector 5
As shown in FIG. 3, each of the gears a and 5b generates a corresponding pulse voltage every time the teeth of the gears 4a and 4b on the shaft 3 system facing each other pass in front of the gears.

[0007] The speed counter 22 gate on the signal from the high frequency reference signal oscillator 20 at the rise of the detection signal P _a contactless electromagnetic rotary pulse detector 5a, and gated off at the rising edge of the next signal, in between The wave number N of the high-frequency reference signal is counted.

[0008] The phase difference counter 21 gate on the input from the high-frequency reference signal oscillator 20 at the rising edge of the input signal P _a from the non-contact type electromagnetic rotary pulse detector 5a,
Input signal P from non-contact type electromagnetic rotation pulse detector 5b
The gate is turned off at the rise of _b , and the wave number ΔN of the high-frequency reference signal during this period is counted.

The divider 23 calculates the ratio between the count value N of the speed counter 22 and the count value △ N of the phase difference counter 21.
The signal is transmitted to the D / A converter 24, and the D / A converter 24 converts the signal into an analog amount and outputs the analog amount. The torsional angular displacement is measured.

The reason why the torsional angular displacement of the shaft is obtained by the above-mentioned conventional device will be described below. When the shaft is rotating at a constant speed, the rotation pulse period T of the output signal P _a contactless electromagnetic rotary pulse detector 5a is represented by the following formula (3).

T = θ _p / (360 · _fr ) (3) where θ _p is the pitch angle of the teeth of the gears 4a and 4b, and _fr is which is the axis of the rotation frequency (H _z). Further, the phase difference time △ T between the detection signals P _a, P _b where contactless electromagnetic rotary pulse detector 5a and 5b is output is represented by the following formula (4).

ΔT = Δθ / (360 · _fr ) (4) Δθ = θ _z + θ _o where θ _z is the gear 4a and the gear 4b. _Θo is a torsion angle proportional to the load on the rotating body, which is a constant determined by the manner of attachment to the shaft 3 and the manner of attachment of the non-contact electromagnetic rotary pulse detectors 5a and 5b.

[0013] A torsional vibration occurs in the rotating shaft system, and △ θ _i
When twisted, the phase difference time ΔT becomes the phase difference time ΔT _i to which this variable ratio is added, and this ΔT _i is given by the following equation (5).
Indicated by

ΔT _i = (Δθ + Δθ _i ) / (360 · _fr ) (5) Assuming that the ratio between the rotation pulse period T and the phase difference time ΔT _i is X _i , X _i is expressed by the following equation (6).

X _i = ΔT _i / T = θ _z / θ _p + θ _o / θ _p + Δθ _i / θ _p (6) The first term θ _z / θ _{p on the} right side in the above equation (6) Is gear 4
a, 4b and constants determined when the rotation pulse detectors 5a, 5b are installed, the second term θ _o / θ _p is a value proportional to the load, and the third term Δθ _i / θ _p is a torsional vibration component. .

[0016] The high frequency reference signal and the detection signal P _a count value N of the speed counter 22 counts you enter is represented by the following formula (7).

[0017] _{N = f c × T ............................................................... (} 7) Here, f _c is the high frequency reference signal frequency.

[0018] In addition, high frequency reference signal and the detection signal P _a, P
_The count value △ N counted by the phase difference counter 21 to which _b is input
_i is expressed by the following equation (8).

ΔN _i = f _c × ΔT _i (8) The count value N and ΔN are input to the divider 23 and The ratio of the count values N and △ N shown in equation (9) is output.

ΔN _i / N = △ T _i / T = X _i (9) The ratio of the count value N and ΔN output from the divider 23 is a X _i shown by equation (6) as shown in the equation (9), includes a torsional vibration components in the X _i, torsion angle by taking this A displacement is obtained.

[0021]

It is desirable that the measurement resolution of the torsion angle displacement measuring device be a constant value regardless of the rotational speed of the shaft. In addition, there are several types of rotary machines ranging from several to tens of thousands of rotations per minute, and it is desirable that all of them can be similarly measured by the torsion angle displacement measuring device.

[0022] In the conventional torsional angular displacement measuring apparatus, the measurement resolution is one determined by the oscillation frequency f _c of the high frequency reference signal oscillator as shown in the following equation rotation pulse frequency f _r.

Measurement resolution = (360 · f _r ) / (θ _p · f _c ) That is, the measurement resolution decreases in proportion to the rotation speed of the shaft. Increasing the high-frequency reference signal frequency can improve the measurement resolution, but the count value counted by the speed counter also increases, and a large number of digits is needed to cover the low rotation of the shaft. And had to use expensive counters.

The present invention is to solve the above-mentioned problems.

[0025]

According to the present invention, there is provided a torsion angle displacement measuring device comprising: a gear installed at a plurality of points on a rotating machine shaft system;
A non-contact type electromagnetic rotary pulse detector provided on the stationary side opposed thereto, a rotary encoder provided at the end of the rotary machine shaft, and the rotary encoder and the plurality of rotary pulse detectors were connected. It is characterized by comprising a phase difference counter and a D / A converter to which the counter is connected.

[0026]

In the above, the rotary encoder attached to the end of the rotary machine shaft system oscillates and outputs a fixed number of wave number signals for one rotation of the shaft.

The phase difference counter gates the input from the rotary encoder at the rise of the input signal from one of the non-contact type electromagnetic rotary pulse detectors, and inputs the input from the other non-contact type electromagnetic rotary pulse detector. The gate is turned off at the rise of the signal, and the number of oscillation waves of the rotary encoder including the torsional angular displacement of the shaft during this period is counted. This count is D /
The A converter receives the input, converts it to an analog signal, and outputs it.

In the present invention, unlike a conventional apparatus using a high-frequency reference signal having a constant wave number independent of the rotation frequency of the shaft, a rotary encoder for outputting a fixed number of wave number signals for one rotation of the shaft is provided. Since the output signal is used, the measurement resolution is given by the following equation.

Measurement resolution = 360 / (θ _p · K) Here, θ _p is the pitch angle of the teeth, K is the number of oscillation waves per rotation of the shaft, and the measurement resolution includes the rotation frequency of the shaft. Not.

As described above, a measuring apparatus capable of maintaining a constant measuring resolution even when the rotational frequency of the shaft changes is realized.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. 1 (a) and 1 (b) show a high-pressure turbine rotor 1 of a shaft 3 on which a high-pressure turbine rotor 1a, a low-pressure turbine rotor 1b, and a generator rotor 2 are sequentially provided.
Non-contact type gears 4a, 4b provided at the shaft end on the a-side and the shaft end on the generator rotor 2 side, and non-contact type which are respectively provided to face the teeth of the gears 4a, 4b and output detection signals Pa, Pb, respectively. electromagnetic rotary pulse detector 5a, 5b, the rotary encoder 10, the rotary encoder 10 and the rotation pulse detector 5a for outputting the connected signal P _e in the axial end of the generator rotor 2 side of the shaft 3, respectively from 5b of the output signal P _e, the phase difference counter 1 for outputting a P _a, the oscillation wave number of the rotary encoder 10 to input P _b △ N
1 and a D / A converter 12 for inputting the oscillation wave number ΔN from the counter 11 and outputting an analog signal.

In the above, the rotary encoder 10
Oscillates a wavenumber signal P _e is a fixed number for one rotation of the shaft 3, and outputs. Phase difference counter 11 is gated on at the rising edge of the input signal P _a of the input P _e from the rotary encoder 10 from the non-contact type electromagnetic rotary pulse detector 5a, the input from the non-contact type electromagnetic rotary pulse detector 5b gated off at the rising edge of the signal P _b, and counts the oscillation wave number △ N of this period of the rotary encoder 10.

The count value ΔN is transmitted to the D / A converter 12
Output from the D / A converter 12 as an analog signal.
It is. Note that the oscillation frequency of the rotary encoder 10 is
Number f _eCan be obtained by the following equation (1).

F _e = K · fr _r (1) where K is the number of oscillation waves per one rotation of the shaft 3, and _fr is This is the rotation frequency of the shaft 3.

[0035] In this embodiment, it is assumed that high frequency reference signal frequency f _c in the formula (8) in the conventional device is replaced by the oscillation frequency f _e of the rotary encoder 10, the count value △ N of the phase difference counter 11 _i is represented by the following equation (2).

[0036] _{△ N i = (K / 360} ) · (△ θ + △ θ i) .................. (2) Since the above formula (2) is not included rotational frequency f _r of the shaft, count value △ N _i is the value that is directly proportional to the torsional angular displacement, not affected by the axial rotation frequency f _r.

The measurement resolution is determined by the number of oscillation waves per rotation of the rotary encoder shaft. For example, when a rotary encoder of 36000 pulses / rotation is used, the measurement can be performed at a measurement resolution of 1/100 degrees regardless of the rotation.

As described above, a measuring apparatus capable of maintaining a constant measuring resolution even when the rotational speed of the shaft changes is realized.

[0039]

The torsion angle displacement measuring device according to the present invention has
A rotary encoder that outputs a fixed number of wave number signals with respect to rotation is provided at the end of the rotating machine shaft system, and a plurality of coaxially provided rotating pulse detectors are provided opposite to each other, and the same plurality of rotating pulses are provided. The phase difference counter to which the detector and the rotary encoder are connected gates the wave number signal output by the rotary encoder by the output signal of the rotation pulse detector by gate-on and gate-off, even when the rotation frequency of the shaft changes, A measurement device capable of maintaining a constant measurement resolution is realized.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an embodiment of the present invention, in which (a) is an explanatory view of a rotary pulse detector and a rotary encoder provided in a turbine generator, and (b) is a rotary pulse detector and a rotary encoder. Is connected to the phase difference counter and D /
It is explanatory drawing of an A converter.

FIG. 2 is an explanatory diagram of a conventional device.

FIG. 3 is an explanatory diagram of a pulse waveform according to the conventional device.

[Explanation of symbols]

 3 axis 4a, 4b Gear 5a, 5b Non-contact electromagnetic rotation pulse detector 10 Rotary encoder 11 Phase difference counter 12 D / A converter

Claims (1)

(57) [Claims] 1. A gear installed at a plurality of points on a rotating machine shaft system, a non-contact type electromagnetic rotating pulse detector provided on the stationary side opposed thereto, and a gear provided at an end of the rotating machine shaft. A rotary encoder 10, a phase difference counter to which the rotary encoder and the plurality of rotation pulse detectors are connected, and a D / A converter to which the counter is connected. apparatus.