JPH0315688B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a digital dynamic unbalance testing machine that measures the dynamic unbalance (expressed by the dynamic unbalance amount and dynamic unbalance angle) of a rotating body of rotating equipment.
In particular, the present invention relates to a dynamic unbalance measuring device for a rotating body (hereinafter referred to as a rotor) having two unbalance correction surfaces, such as the armature of a general-purpose motor.

Generally, if the rotor has an unbalance that exceeds the allowable limit, vibration and noise will be generated during operation, which will significantly reduce the efficiency and life of the rotating equipment, so it is necessary to measure the rotor and dynamic unbalance and correct the unbalanced part. There is. And recent rotating equipment has become faster,
Since there is a strong demand for high performance and low cost, automating the motion balance measurement and subsequent imbalance correction process and improving the accuracy have become issues.

By the way, calculations, storage and display in the circuit section of the measuring device of the conventional dynamic balance tester were all analog type.

However, it has become possible to relatively easily produce high-performance machines for dynamic imbalance correction at low cost using microcomputers and numerical control devices, which have developed rapidly in recent years. Since the device uses digital signals and requires digital values as unbalance data to the corrector, conventional measuring instruments cannot be directly connected.

In addition, with the measuring instruments of conventional dynamic balance testers,
This is called pre-driving before measurement.

Adjustment work for setting the constants of the vibration system in the measuring instrument, that is, adjusting the potentiometers 6 to 15 while monitoring the unbalance amount and angle indicators 1 to 4 in Fig. 1.
It is necessary to operate the changeover switch 6, and this adjustment work is so delicate that only an experienced person can do it, and if the adjustment is incorrect, the measurement accuracy will be deteriorated.

Even when a person reads an unbalance using an indicator, there are problems such as errors due to individual differences in reading and a reading limit due to the size of the minimum scale due to the limit of the size of the indicator.

As will be explained later, in order to measure dynamic unbalance, a circuit is first required that separates and calculates the amplitude and phase of the unbalance signal component that has a predetermined relationship with the dynamic unbalance from the vibration detector output. be. In conventional measuring instruments, a synchronous rectifier circuit and a smoothing circuit are used to convert the amplitude of only the sine wave component and cosine wave component of the unbalanced signal component in the vibration detector into the corresponding DC voltage. many. Therefore, unless the time constant of the smoothing circuit is lengthened, there will be no sufficient filter effect, and it will take several times as long to stabilize the DC voltage, so there is a drawback that the measurement time as a measuring instrument becomes long, and analog Measurement errors also occurred due to DC voltage amplification in the calculation circuit and drift associated with calculation.

As described above, conventional measuring instruments have problems such as automatic correction of unbalance, adjustment during preliminary drive, and measurement accuracy measurement time, and the present invention solves these problems by making it a digital measuring instrument. It is something that will be resolved.

Hereinafter, as an example, the case of a measuring instrument for a horizontal dynamic balance tester will be explained based on FIGS. 2 to 5. Figure 2 is a panel diagram of the measuring instrument, 16, 18
is a number display that displays the amount of unbalance between the left and right correction surfaces including the decimal point, and 17 and 18 are number displays that indicate the unbalance angle between the left and right correction surfaces, eliminating individual differences in reading with conventional analog indicators. There is. 26 is a confirmation lamp for the operator, which will be explained later.

Reference numeral 20 is a changeover switch, which is set to Q ₂ during normal measurement and set to Q ₁ during pre-driving, push button switches 21, 22, 23, trial weight weight setting digital switch 24, and trial weight angle setting digital switch. 25 is used. FIG. 3 shows a simplified diagram of the main body of a general horizontal dynamic balance tester. When the drive motor 27 rotates, the transmission pulley 28, belt 29, and tension pulleys 30, 31
The rotor 33 to be tested, which rests on the stretched belt 32, rotates freely due to friction with the belt 32. The shaft of the rotor 33 has two bearings 3 on the left and right.
4 and 35, and vibration detectors 36 and 37 are installed independently on the left and right sides to detect vibrations of the bearings. In addition, the bearings are made of spring materials 38 and 39.
It is supported so that it can move freely only in the horizontal direction. When the rotor 33 rotates, the dynamic unbalance of the rotor causes the bearing to vibrate, so that a sinusoidal unbalance signal voltage synchronized with the rotational speed of the rotor is generated in the left and right vibration detectors 36 and 37. The actual signal voltage has various noise components superimposed on it, resulting in output waveforms such as S _L and S _R shown in FIG. 4, for example.

Therefore, among the output signals S _L and S _R (referred to as vibration signals) of the vibration detectors 36 and 37 containing such noise components, unbalance signal components, that is, frequency components synchronized with the rotational speed of the rotor are detected. Circuits for measuring the magnitude and phase of are required for each of the left and right sides.

On the other hand, in order to measure dynamic unbalance, it is necessary to determine the amount of unbalance at which position (angle) of the rotor as a reference (0 degrees), so a phase reference point is required. It is.
Therefore, as shown in Fig. 3, there is a mark 40 on the rotor 33.
, and detect this with the mark detector 41, and use the rising edge (or falling edge) of the pulse signal shown in FIG. 4 S _P as the reference phase. By counting the output S _P of the mark detector for one second, the number of revolutions of the rotor can also be measured. (S _P is referred to as a reference phase signal) When the rotation of the motor becomes stable and the number of rotations of the rotor becomes stable, a measurement start signal STA shown in FIG. 5 is output from the tester main body to the measuring instrument.

Here, to explain the theory of the vibration system, in Fig. 5, the parts numbered 33 to 41 are the same as those explained in Fig. 3, and the dynamic unbalance vector on the left correction surface of the rotor is expressed as U. → _L ,
The unbalance vector on the right side is set as U→ _R , and from among the outputs S _L and S _R of the respective vibration detectors 36 and 37, the output signal S _P of the mark detector 41 is used to synchronize with the rotation speed of the rotor. Assuming that only those components can be extracted, let the voltage vectors be V→ _L and V→ _R . In this vibration system, the following equation holds true based on vibration theory.

U → _L = A → V → _L + B → V → _R ... (1) U → _R = C → V → _L + D → V → _R ... (2) Here, A →, B →, C →, D→ is a vector constant specific to this vibration system including the rotor, which is determined by the shape of the rotor, the weight of items attached to the vibration system such as weight bearings, the sensitivity and mounting position of the vibration detector, the mounting position of the mark detector, etc. be.

Next, we will explain a method of calculating only the unbalanced signal component in the vibration signals S _L and S _R including noise components using a microcomputer.
This will be explained with reference to FIG.

In FIG. 5, the signal S _P of the mark detector 41
is amplified and shaped by the preamplifier 42 and input to the flip-flop circuit 43, which outputs a signal that is inverted every cycle as shown in the signal S1 in FIG. 44 is an oscillator that oscillates pulses at a period less than about 1/1000 of the period T _S of the vibration signal, and its output is input to a gate circuit 45.
A signal S2 is obtained under the control of the signal S1.
The signal S2 is input to the counter 46 and counted.

Therefore, if the counter 46 is reset at time _T0 , it counts the pulses of the oscillator 33 from the pulse output time _T0 of the reference phase signal _SP to the output time _T1 of the next pulse, so that the final If the count value is M, then one pulse interval of the oscillator 44, that is, S2
Since one period of vibration T _S is 360 degrees, the pulse interval θ is θ≒360/M (degrees) (3). Therefore, the angle of the vibration signal at the rise of each pulse of S2 is θ°, 2θ°, 3θ°...360
°
(=Mθ°). On the other hand, the output of the counter 46
ADR is 0, 1, 2...M in order as shown in Figure 4.
and increases.

By the way, the vibration signals S _L and S _R are each independently amplified by preamplifiers 47 and 48, and input to A-D converters 49 and 50 that can discriminate polarity. Since the aforementioned signal S2 is given as a conversion start signal to the A-D converters 49 and 50, A-D conversion is started from the rising edge of the pulse of S2, and upon completion, the voltage is converted into digital conversion data D _AL and D _AR . Completion signal pulses S3 and S4 are output. this data
D _AL , D _AR and completion signals S3 and S4 serve as data inputs and write pulse signals for the memory circuits 51 and 52, respectively, and digital values of the oscillating voltage are written at each pulse timing of S3 and S4. As mentioned above, since the address inputs of the memory circuits 51 and 52 are connected to the output of the counter 46, the vibration signals are sequentially transmitted at the angle θ.
The value of S _L1 and S _R1 is “1” and the value of angle 2θ S _L2 ,
S _R2 will be stored as address "2"... That is, the last vibration signal voltage S _LM , S _RM in FIG.
The value of is stored at address "M", and the value of S _LQ at address Q,
S _RQ is stored at address "Q".

Now, the signal S1 is input to a vibration signal of a microcomputer 54 (hereinafter abbreviated as microcomputer) via an interface circuit 53. The microcomputer 54 starts calculation, which will be described later, from the fall time _T1 of the signal _S0 according to the program flow in the program memory 55 in which the program is stored, and also outputs a calculation-in-progress signal S5 and outputs a calculation in progress signal S5 to the flip-flop. 43. When the calculation is completed, this signal S5 is turned off. Then, since the falling differentiation circuit 56 outputs the reset pulse signal S6 at the falling edge of S5, the counter 46 is reset by the signal S6. The reset state continues until _T2 , which is the same state as the initial state _T0 in FIG.

Because the calculation took a long time, if the calculation does not finish during the period T ₁ to _{T 2} , the calculation in progress signal S5 is
Since it remains ON, the flip-flop circuit 43
remains reset and does not reverse even at _T2 . Therefore, the gate circuit 45 is opened and A-
The D conversion start signal S2 is never generated, and the contents of the storage circuit do not change. If the calculation signal S5 is off before the next phase reference signal S _P turns on, the output of the flip-flop circuit 43 is inverted at the fall of this S _P and becomes the initial state.

When the calculation signal S5 turns ON, the memory circuits 51 and 52 store A- at the address ADR specified by the counter 46.
From the previous state in which the D-converted vibration signal data D _AL and D _AR are written and stored, the vibration signal data stored according to the address data A _L and A _R specified by the microcomputer are transferred to the data buses D _L and D _A. It is possible to switch to a state where it can be read out. Also,
The microcomputer reads the value of the output ADR of the counter 46 via the interface circuit 53, and outputs the signal S2.
The pulse interval θ can be calculated using equation (3).

The microcomputer 58 uses Fourier transform to calculate the amplitude values of the sine wave component and cosine wave component of the unbalance signal component synchronized with the rotation of the rotor from the vibration signals S _L and S _R separately for the left and right sides. I will explain how to do that. The microcomputer 58 first reads the final count value M of the counter and calculates the above formula (3), and calculates A-D.
Calculate the conversion data acquisition angle interval θ. Next, the voltage value S _L1 of the left vibration signal stored in order from address “1” in the left vibration signal storage circuit 51,
_{S L2 , .}

X _L = 1/M {S _L1 cosθ°＋S _L2 cos2θ°＋…S _LM co
sMθ°}=1/M _M 〓 ^Q=1 S _LQ cosQθ° ...(4) Similarly, Y _L =1/M _M 〓 ^Q=1 S _LQ sinQθ° ...(5) The program memory 55 is In addition to such calculation programs, there is a memory area (called a RAM area) where the contents can be freely written and read, and the calculated values of X _L and Y _L are temporarily stored in a part of the microcontroller. Remember it. When these operations are completed, the microcomputer similarly calculates the cosine wave component X _R and sine wave component Y _L of the vibration signal on the right using the following equations (6) and (7), and stores them in the RAM area. .

X _R = 1/M _M 〓 ^Q=1 S _RQ cosQθ° ……(6) Y _R = 1/M _M 〓 ^Q=1 S _RQ sinQθ° ……(7) Vibration is caused by equations (4) to (7) The unbalance component signal within one period of the signals S _L and S _R was calculated, but if the noise component is large or the period of the noise component is close to the rotation period of the rotor, the noise component may be However, it is inaccurate to determine the unbalanced signal component based on the result of the above calculation only once.
Therefore, a more accurate value can be obtained by repeating this calculation over several dozen cycles or more and calculating the average value of the answers.

The operation is performed as follows.

When the measurement start signal STA from the test machine body turns ON, the microcomputer senses this via the interface circuit 53, and when the S1 signal turns OFF, it first turns ON and OFF the calculation signal S5. A reset pulse S is generated by creating a pulse signal, resetting the flip-flop 43, and generated by the differentiating circuit 56.
At step 6, the counter 46 is also reset to its initial state. After that, each circuit operates as described above and formula (4)
In steps (7) to (7), the initial calculation values X _L1 , Y _L1 , X _R1 , and Y _R1 are calculated, and these values are stored in the program memory RAM area. In the next cycle, another
In the RAM area, add the new X _L2 calculated using the above calculation,
Store the values of Y _L2 , X _R2 , and Y _R2 . Repeat the same below.

By repeating such calculations for a certain period of time (for example, 3 seconds) after the measurement start STA from the motion balance tester body is turned on, Fourier transform values over several dozen cycles or more can be obtained. Next, these average values L _X ,
Calculate L _Y , R _X , and R _Y . When the sum is accumulated C times, it is expressed by the following equation.

L _{X =} 1 _/ C (X _L1 +X _L2 +X _L3 +...X _LC ) ⁼ 1/ _{C C 〓} ^P= ₁ … ₍ 9 ₎ R _X = ¹ / _{C C 〓} ^P= 1 Count and
It also requires a program to be stored in its own register or RAM area.

Considering the composite _voltage vectors L _{O and R O of L} →
The difference in the reference point of the mounting position of 7 and the preamplifier 42,
43 and 44, the phase is delayed by δ _L degrees and δ _R degrees, respectively, with respect to the reference phase signal. However, since the magnitude thereof is proportional to the magnitude of the unbalance signal components V→ _L , V _R in the outputs S _L , S _R of the vibration detectors 36, 37, k _L , k _R are positive. As a constant, V→ _L =k _L ∠δ° _L・L→ ₀ =k _L δ° _L (L _X +jL _Y )……(
12) V→ _R =k _R ∠δ° _R・R→ ₀ =k _R δ° _R (R _X +jR _Y )……(
13) becomes. However, (j ² = -1) Substituting into the vibration theory formulas (1) and (2), U→ _L = A→・k _L ∠δ° _L (L _X +jL _Y )+B→・k _{R
δ ° R ( R _ _ _ _
° R ( R _ _ _} +jR _Y ) ...(16) U → _R = (e+jf) (L _X +jL _Y ) + (g+jh) (R _X +
jR _Y ) ...(17) becomes.

However, A→k _L ∠δ° _L = a+jb, B→k _R ∠δ° _R = c+jd C→k _L ∠δ° _L = e+jf, D→k _R ∠δ° _R = g+jh The values of a to h above are , is a constant specific to this vibration system, but as mentioned above, its value changes depending on the shape and weight of the rotor.

Therefore, it is necessary to measure and set these eight unknown constants every time the rotor model changes, and this corresponds to the work called preliminary driving described above.

Next, using the calculated values of L _X , L _Y , R _X , and R _Y , the microcomputer 54 executes will explain the operation of calculating the left and right dynamic unbalance and angle of the rotor, as well as the constants, along with the operating procedure for the operator.

In FIG. 5, the parts numbered 16 to 26 are the same as those explained in FIG. The microcomputer 54 detects the states of the switches 20 to 25 via the interface circuit 53, and displays the left unbalance amount and angle on the number displays 16 and 17, and the right unbalance amount and angle on the number displays 18 and 19. Display each. Furthermore, for automatic correction, digital signal outputs of left and right unbalance amounts and angles, EX and OUT, are outputted from the interface circuit 53. In addition,
26 is a confirmation lamp for the worker and microcomputer 5
ON-OFF control is performed by 4.

Now, pre-driving is performed using any rotor, and the operating procedure is as follows: 1. Set the selector switch 20 to the _Q1 position and notify the microcomputer of pre-driving. 2. The operator moves the rotor to balance the test machine itself. and rotate the drive motor. When the rotational speed of the rotor becomes constant and the vibration state becomes stable, the measurement start signal STA is output from the test machine body, so the microcomputer performs the above calculation,
Store the values of L _X , L _Y , R _X , and R _Y . Now, _let L _{X =} L _X1 , _{L Y = L Y1} , R Similar to equations (16) and (17) where the balance vector is U → _R1 , U → _L1 = (a + jb) (L _X1 + jL _Y1 ) + (c + jd) (R _X1 + R _Y1 ) ... (18) U → _R1 =(e+jf)(L _X1 +jL _Y1 ) +(g+ _jh ) ₍ R

The _{microcomputer} memorizes the calculated L _X , L _Y , _R Press 21 and
A state in which the calculation formulas (18) and (19) hold, that is, the left and right unbalanced signal components obtained by calculation.
Tell the microcontroller that L _X = L _X1 , L _Y = L _Y1 , R _X = R _X1 , and R _Y = R _Y1 . Then, the lamp 26 is turned off under the control of the microcomputer.

3 Stop the drive motor and add a test weight of known weight at a position α degrees from the photo mark position on the left correction surface of the same rotor. Set the rotor on the test machine body again and rotate the drive motor. The calculated values in this case are L _X = L _X2 , L _Y =
_{Assuming that L Y2 , R _ _ _} 20), and this unbalance vector is added to the left correction plane, so the following relationship holds true.

_{U → L1} +W→ _L = (a+ _jb ) (L _X2 +jL _Y2 ) + ( _c +jd) ( _{R X2} + R _Y2 ) ... (22) The operator confirms that the lamp 26 is lit, sets the weight W ₁ of the test weight and its angle α on the digital switches 24 and 25, and then presses the push button switch 22. Then, the microcomputer inputs the numerical values of the digital switches 24 and 25 and stores them in the RAM area as W _L grams and α degrees, and also stores the unbalance signal components calculated at this time in the respective RAM areas L _X2 and L _Y2 , _RX2 ,
Store the value of R _Y2 .

4 Stop the drive motor, remove the trial weight attached to the left side correction surface of the rotor, and add an immediate value trial weight at the β degree position on the right side correction surface. The weight may be different from the weight added to the right correction surface. As for the weight W _R , the following formula holds true as in the case on the left.

W → _R = W _R cosβ° + jW _R sinβ°……(23) When the rotor rotates, an STA signal is output, and the unbalanced signal components L _X , L _Y , R _X , R _Y are sent to the microcontroller.
have them calculate. _{If these values} in _{this state are respectively L} +R _Y3 ) ...(24) U→ _R1 +W→ _R = (e+jf) (L _X3 +jL _Y3 ) +(g+jh) (R _X3 +R _Y3 ) ...(25)

The operator similarly confirms that the lamp 26 is lit, sets the values of W _R and β on the digital switches 24 and 25, and presses the push button switch 23. Then, the microcontroller reads the digital switch values and reads L _X3 , L _Y3 , R _X3 , R _Y3
are stored in their respective RAM areas.

Next, L _X1 ~ _{L X3} , L _Y1 ~ in equations (18) to (25)
Using L _Y3 , R _X1 to R _X3 , R _Y1 to R _Y3 , W _L , aW _R , and β as constants, the values of eight constants a to h are calculated as unknowns.

To simplify the calculation, if we assume that the angle α = β = 0° added by the trial weight, equations (20) and (23) become W → _L = W _L ... (20a) W → _R = W _R ...(23a) _Now , _{K 1 =} L _{X1 −L X2} ... ₍ 26) _{K 2 = R …} (29) K ₅ = _{L X1} −L _X3 … ₍ 30) _{K 6} = _{R X1 −R Y3} ...(33) Δ=(K ₁ ² +K ₃ ² )(K ₆ ² +K ₈ ² )+(K ₂ ² +K ₄ ² )(K ₅ ² +K
₇ ² ) + 2 {(K ₂ K ₃ −K ₁ K ₄ ) (K ₅ K ₈ −K ₆ K ₇ ) −(K ₁ K ₂ +K ₃ K ₄ )(K ₅ K ₆ +K ₇ K ₈ )}… ...(34) and solving the unknown constant, a=W _L /Δ{K ₄ (K ₅ K ₈ −K ₆ K ₇ )+K ₂ (K ₅ K ₆ +K ₇ K ₈
)−K ₁ (K ₆ ² +K ₈ ² )} b=W _L /Δ{K ₂ (K ₅ K ₈ −K ₆ K ₇ )−K ₄ (K ₅ K ₆ +K ₇ K ₈
)+K ₃ (K ₆ ² +K ₈ ² )}……(35) c=W _L /Δ{K ₁ (K ₅ K ₆ +K ₇ K ₈ )−K ₃ (K ₅ K ₈ −K ₆ K ₇
)−K ₂ (K ₅ ² +K ₇ ² )}……(36) d=W _L /Δ{−K ₃ (K ₅ K ₆ +K ₇ K ₈ )−K ₁ (K ₅ K ₈ −K ₆
K ₇ )+K ₄ ² (K ₅ ² +K ₇ ² )}...(38) e=W _R /Δ{K ₆ (K ₁ K ₂ +K ₃ K ₄ )−K ₈ (K ₂ K ₃ −K ₁ K ₄
)−K ₅ (K ₂ ² +K ₄ ² )}……(39) f=W _R /Δ{K ₈ (K ₁ K ₂ +K ₃ K ₄ )−K ₆ (K ₂ K ₃ −K ₁ K ₄
)+K ₇ (K ₂ ² +K ₄ ² )}...(40) g=W _R /Δ{K ₅ (K ₁ K ₂ +K ₃ K ₄ )+K ₇ (K ₂ K ₃ −K ₁ K ₄
)−K ₆ (K ₁ ² +K ₃ ² )}……(41) h=W _R /Δ{K ₅ (K ₂ K ₃ −K ₁ K ₄ )−K ₇ (K ₁ K ₂ +K ₃ K ₄
) + K ₈ (K ₁ ² + K ₃ ² )}...(42).

When the calculation of the eight constants a to h is completed, the microcomputer turns off the lamp 26.

Preliminary driving is completed with the above three measurements, and any unbalance of the rotor can be measured.

To perform a measurement, the operator must press the changeover switch 20.
is switched to the Q2 position to notify the microcomputer that unbalance measurement will be performed, and the microcomputer senses this via the interface circuit 57 and receives the measurement start signal STA from the test machine main body.
Calculate unbalanced signal components L _X , L _Y , R _X , R _Y . Next, based on this value, the unbalance between the left and right correction surfaces of the rotor is calculated. That is, if the left and right unbalance amounts of the rotor are U _L and U _R and the unbalance angles are φ _L and φ _R , respectively, then U _L = U→ _L ∠φ _L °=U _L cosφ _L °＋jU _L sinφ _L
...(43) U _R =U→ _R ∠φ _R °=U _R cosφ _R °＋jU _L sinφ _R .
...(44) Therefore, transforming equation (17), U _L = √( _X − _Y + _X − _Y ) ² + (
_Y + _X + _Y + _X ) ² ...(45) φ _L. ＝tan ^-1 aL _X −bL _Y ＋cR _X −dR _Y ／aL _Y ＋bL _X ＋cR _Y ＋d
R _X ……(46) _Similarly ^, from equation ( _{18 ) ,} U _R =√(
_Y + _X + _Y + _X ) ² ...(47) φ _R. = tan ^-1 eL _X −fL _Y +gR _X −hR _Y /eL _Y +fL _X +gR _Y +h
R _X ... (48) Therefore, these U _L , φ _L , U _R , and φ _R are displayed on the number displays 16, 17, 18, and 19, respectively.

As in this calculation example, the installation angle α of the trial weight,
In many cases, β may be fixed at 0 degrees, but it is clear that if it is particularly necessary, α and β can be set in the digital switch 25 and the calculation formula can be solved in the same way. It is generally inconvenient to fix the set values of the test weights W _L and W _R , but if it is okay to fix them, register the values as constants in the microcontroller's program memory 55. Keep it, digital switch 24
can be eliminated.

The A/D converter used in this embodiment is capable of decomposing ±1 volt into 1 bit for polarity determination and 11 bits, and commercially available LSi can be obtained at low cost. When the input value of the A-D converter exceeds 1 volt, a changeover switch is placed in front of the A-D converter, and the signal is divided and inputted to the A-D converter. By adding a program to control this partial pressure switch, it is possible to manufacture a measuring instrument that can automatically measure a wide range of unbalance amounts.

On the other hand, in order to calculate the unbalance components _{L X , L Y} , _R It is better to have fewer noise components in the input. For this purpose, the preamplifiers 47, 48 and the A-D converter 4
9 and 50, a bandpass filter is inserted that allows only the vicinity of the unbalanced signal frequency pole to pass through. Although the bandpass filter causes a phase shift of the unbalanced component, this phase shift is also included in δ _L and δ _R in equations (12) and (13), so all calculation formulas described so far No need to change.

In the example, as shown in FIG.
We have devised a way to reduce the number of circuits by sequentially capturing and storing the vibration signals between cycles in a memory circuit and performing calculations during the next cycle, but one by one the same memory circuit, counter, frequency divider circuit, and gate are used. If a circuit is provided, and when one side is writing A-D conversion data, the microcomputer reads and calculates the data stored in the other memory circuit, and this process is repeated alternately. It becomes possible to extract the balance signal component.

In the embodiment _{shown in FIG .}
However, since the RAM area of the program memory 55 has the same function as the storage circuit, the microcomputer manages the hardware components (circuits). It becomes possible to use software as a substitute. That is, as shown in FIG. 6 which is the second embodiment, the memory circuits ₅₁ and 52 of _FIG . It can be implemented on the same principle by adding an operation program that the microcomputer sequentially stores in the RAM area of the program memory 55 at the timing of .

Similarly, the differential circuit 5 in FIGS. 5 and 6
It goes without saying that the output signal S6 of No. 6 can be outputted from the interface circuit 53 by adding a microcomputer program.

FIG. 7 is a flow chart showing an outline of the operation of the microcomputer of the first embodiment shown in FIGS. 2 to 5.

In this way, the present invention digitally displays the unbalance amount and angle data and also outputs it to the outside, which eliminates individual differences in reading the indicator, which is a drawback of analog systems, and makes it easier to use with automatic unbalance correction machines. Bonding can also be done easily and inexpensively. Furthermore, there is no adjustment of the potentiometer that is required in the case of an analog measuring instrument, and it is easy to set the digital switch and operate the push button switch. There is also no adjustment error in the potentiometer made by the operator.

On the other hand, calculations, storage, and control are performed by a microcomputer, and most of the circuits are digital circuits, which simplifies the hardware configuration of the measuring instrument and lowers the overall cost. It also disappears.

Furthermore, an oscillator and a counter circuit are used to obtain a counter count value M that is proportional to the rotation period of the rotor, while a signal for one period of the vibration detector is converted into a digital value at the timing of the output pulse of the oscillator and stored. Then, by calculating the unbalance signal component by Fourier transform using the count value M, the average value of the unbalance information can be obtained as stable data in the same measurement time regardless of the high or low rotational speed of the rotor. It will be done. Therefore, compared to conventional measuring instruments, the measurement time is shortened, especially when the rotational speed of the rotor is low, and this has a great industrial advantage of improved productivity.

As described above, the error factors of the measuring device are reduced as described above, and there are significant advantages such as shortening of measurement time.

[Brief explanation of drawings]

Fig. 1 is a panel diagram of a measuring device of a conventional dynamic balance testing machine, Fig. 2 is a panel diagram of a measuring instrument of an embodiment of the present invention, and Fig. 3 is a simplified diagram of the main body of a horizontal dynamic balance testing machine. Figure 4 shows the output S _L of the vibration detector on the left side of the main body, the output S _R on the right side of the main body, and the output of the reference mark detector.
A waveform diagram of S _P and a timing chart of the first embodiment, FIG. 5 is a block diagram of the first embodiment of the present invention,
FIG. 6 is a block diagram of the second embodiment of the present invention, and FIG. 7 is a schematic flowchart of the operation of the microcomputer in the first embodiment. 16... Number display for left unbalance amount, 17...
... Left side unbalance angle number indicator, 18... Right side unbalance amount number indicator, 19... Right side unbalance angle number indicator, 20... Changeover switch, 21
~23...Push button switch, 24,25...Digital switch, 26...Confirmation lamp, 42,4
7, 48... Preamplifier, 43... Flip-flop circuit, 44... Pulse oscillator, 45... Gate circuit, 46... Counter circuit, 49, 50...
A-D converter, 51, 52...Memory circuit, 53...
...Interface circuit, 54...Microcomputer, 55...Program memory, 56...
…Differential circuit, EX.ouT.……External digital output signal.

Claims (1)

[Scope of Claims] 1. A mechanism section that applies rotational force to the test object so as not to disturb vibrations generated due to unbalance of the test object when the test object rotates, and a mechanical section on the rotation axis of the test object. Two vibration detectors installed to detect vibrations in different parts and convert them into electrical signals,
a reference phase detector that generates a pulse signal that is synchronized with the rotation of the test object; an oscillator that determines the timing of sampling the output of the vibration detector;
a counter circuit that counts the output pulses of the oscillator for one cycle of the output signal of the reference phase detector; and a counter circuit that counts the output pulses of the oscillator at each timing of the output pulses of the oscillator. two A-D converters for converting into digital values; a first for sequentially storing data from the two A-D converters during one period of the signal of the reference phase detector;
Let M be the count value of the second storage means and the counter circuit, S LQ be the digital value stored in the first storage means, and S _RQ be the digital value stored in the second _storage means. _, the _unbalanced signal components X _{L ,} ^Y _{L ,} X _{R , Y R} ^are _expressed as = 1/M _M 〓 ^Q=1 S _RQ cosQθ° Y _R = 1/M _M 〓 ^Q=1 S _RQ sinQθ _° ;
a second calculation means for calculating _{respective average} values _{L X ,} L _{Y , R} When the unbalance angles are expressed as U _L , U _R , φ _L , and φ _R , respectively, the formula U _L =√( _X − _Y + _X − _Y ) ² −(
_Y + _X + _Y + _X ) ² φ _L = tan ^-1 aL _X −bL _Y +cR _X −dR _Y /aL _Y +bL _X
+cR _Y +dR _X U _R =√( _X − _Y + _X − _Y ) ² +(
_Y + _X + _Y + _X ) ² φ _R = tan ^-1 eL _X −fL _Y +gR _X −hR _Y /eL _Y +fL _X +
gR _Y +hR _Y (where a, b, c, d, e, f, g, h are constants); and the second calculation means when the test specimen is rotated as a first step. The outputs of the calculation means are memorized as L _X1 , L _Y1 , R _X1 , and R _Y1 , and as a second step, a test weight for the weight W _L is attached to the reference angle of the unbalance correction surface on the left side of the specimen. The outputs of the second calculating means when the test specimen is rotated are stored as L _X2 , L _Y2 , R _X2 , R _Y2 , and as a third step, the test weight is removed and the test specimen is rotated instead. The output of the second calculation means when the test specimen is rotated with a weight W _R attached to the reference angle of the unbalance correction plane on the right side is L _X3 , L _Y3 , R _X3 , R a third storage means for storing the data as _Y3 , an input means for signaling the storage timing of each step, and a, b, c, d,
Calculate the values of e, f, g, and h using the formula a=W _L /Δ{K ₄ (K ₅ K ₈ −K ₆ K ₇ )+K ₂ (K ₅ K ₆ +
K ₇ K ₈ )−K ₁ (K ₆ ² +K ₈ ² )} b=W _L /Δ{K ₂ (K ₅ K ₈ −K ₆ K ₇ )−K ₄ (K ₅ K ₆ +
K ₇ K ₈ )−K ₃ (K ₆ ² +K ₈ ² )} c=W _L /Δ{K ₁ (K ₅ K ₆ +K ₇ K ₈ )−K ₃ (K ₅ K ₈ −
K ₆ K ₇ )−K ₂ (K ₅ ² +K ₇ ² )} d=W _L /Δ{−K ₃ (K ₅ K ₆ +K ₇ K ₈ )−K ₁ (K ₅ K ₈
−K ₆ K ₇ )+K ₄ ² (K ₅ ² +K ₇ ² )} e=W _R /Δ{K ₆ (K ₁ K ₂ +K ₃ K ₄ )−K ₈ (K ₂ K ₃ −
K ₁ K ₄ )−K ₅ (K ₂ ² +K ₄ ² )} f=W _R /Δ{K ₈ (K ₁ K ₂ +K ₃ K ₄ )−K ₆ (K ₂ K ₃ −
K ₁ K ₄ )+K ₇ (K ₂ ² +K ₄ ² )} g=W _R /Δ{K ₅ (K ₁ K ₂ +K ₃ K ₄ )+K ₇ (K ₂ K ₃ −
K ₁ K ₄ )−K ₆ (K ₁ ² +K ₃ ² )} h=W _R /Δ{K ₅ (K ₂ K ₃ −K ₁ K ₄ )−K ₇ (K ₁ K ₂ +
K ₃ K ₄ ) + K ₈ (K ₁ ² + K ₃ ² )} However, K ₁ = L _X1 − L _X2 K ₂ = R _X1 − R _X2 K ₃ = L _Y1 − L _Y2 K ₄ = R _Y1 − R _Y2 K _{5 = L X1 −L X3 K 6 = R X1 −R _} ^_ _{_} ^_ _{_} ^_ _{_} ^_ (K ₂ ² +K ₄ ² ) (K ₅ ² +K
₇ ² ) + 2 {(K ₂ K ₃ −K ₁ K ₄ ) (K ₅ K ₈ −K ₆ K ₇ ) −(K ₁ K ₂ +K ₃ K ₄ )(K ₅ K ₆ +K ₇ K ₈ )} a fourth calculation means for calculating and said U _L , φ _L ,
A digital dynamic balance measuring device characterized by being equipped with output means for U _R and φ _R.