JP2806083B2 - Tire balance 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 tire balance measuring device for measuring a tire unbalance, and more particularly to a tire balance measuring device for measuring an unbalance of a tire while the tire is mounted on a vehicle. It relates to a tire on the car balancer that indicates a position.

[0002]

2. Description of the Related Art As a conventional tire-on-the-car balancer, for example, there is one shown in FIG. This tire balance measuring device supports a wheel 2 on which a tire 1 is mounted via a hub 3, and a longitudinal acceleration sensor 7 is mounted on a spindle 6 mounted on a strut 4 and a suspension lower arm 5. The reflective tape 8 is stuck to. The acceleration sensor 7 detects the acceleration of the longitudinal vibration caused by the imbalance of the tire 1 or the like, and outputs an acceleration detection signal. The optical fiber sensor 10 is turned ON (or OFF) by the light reflected from the reflection tape 8, and an ON / OFF signal of one pulse is output for each rotation of the tire. Then, the acceleration detection signal is amplified by the amplifier 11 and input to the analyzer main body 12. The ON / OFF signal is amplified by the optical fiber sensor amplifier 13 and input to the analyzer main body.

In this tire balance measuring device, measurement is performed as follows. First, the vehicle is driven on a chassis dynamo or the like, and a vehicle speed Vkm / h at which the longitudinal vibration of the tire is maximized, for example, when shimming occurs or steering vibration increases. Next, in order to quantify the amount of imbalance, as shown in FIG.
4 (for example, 20 g) are attached to the positions of the reflection tapes 8 at the wheel ends of the left and right tires, respectively.

When the vehicle travels at a constant speed of Vkm / h, an ON / OFF signal corresponding to the rotation speed of the tire 1 as shown in FIG. 16 is obtained from the optical fiber sensor 10 as a pulse waveform. When it is taken into the analyzer main body 12 and its cycle is counted, the tire rotation primary frequency f ₁ is obtained. At the same time, a vibration as shown in FIG. 17 synthesized by the dummy weight 14 and the unbalance of the tire 1 and the like is obtained from the longitudinal acceleration sensor 7, and an acceleration detection signal obtained by detecting the vibration as acceleration is taken into the analyzer main body 12. When a Fast Fourier Transform (FFT) analysis is performed and its power spectrum is expressed, a distribution as shown in FIG. 18 is obtained. This peak of vibration due to imbalance in the rotating primary frequency f ₁ appears in the power spectrum, detects this as the peak value P _1.

When this peak value P ₁ is observed over time,
It varies with time as shown in FIG. 19, the peak value P ₁ when a certain time has elapsed converges to a constant value P.alpha. The variation of the peak value P ₁ than that caused by the difference of the unbalanced position of the left and right wheels, change of the peak value P ₁ when unbalanced position of the left and right wheels are the same is minimized, maximized at different 180 °. After a certain time, the peak value P
_The reason why ₁ converges to the constant value Pα is that the relative position of the unbalance between the left and right wheels changes with time, which is due to a variation in the diameter of the left and right wheels, a difference in air pressure, and the like.
The time required for the peak value P ₁ is converged to a constant value P.alpha, and fluctuation cycle of P ₁ is a vehicle, vehicle type, also depends on the operating conditions and the like.

Accordingly, conventional records the fluctuations of the peak value P ₁ in a pen recorder 15, the operator to check the convergence to the predetermined value Pα while observing the waveform, the measurement at the first 0 ° Weight Determine the end. When the balance is corrected by the so-called four-point method, after completion of the measurement at the 0 ° weight, the same measurement is performed by replacing the dummy weights 14 at the positions of 90 °, 180 °, and 270 ° shown in FIG. each constant value _{Pα 0, Pα 90, Pα 180} , obtain P.alpha _270.

Next, in the graph as shown in FIG. 13, the 0 ° constant value Pα ₀ is plotted in the positive direction of the Y axis, and is plotted as a 0 ° vector V _0.
α it ₉₀ is plotted in the negative direction of the X-axis and the vector V ₉₀ of 90 °, and the 180 ° constant value P.alpha ₁₈₀ negative direction plotted by the vector V ₁₈₀ of it 180 ° in the Y-axis, the The 270 ° constant value Pα ₂₇₀ is plotted in the positive direction of the X axis, and is set as a 270 ° vector V ₂₇₀ .

Next, the vector V ₀ and the vector V ₁₈₀
Midpoint y _UB and the midpoint of the vector V ₉₀ and the vector V ₂₇₀ x of
_{When UB} is obtained and a vector V _UB connecting the coordinates (x _UB , y _UB ) and the origin is obtained, this is the unbalance weight of the tire, and its angle (position). Therefore, the vector 180 ° opposite to the unbalance vector V _UB is the balance vector V _B. Also unbalanced weight UB
Is calculated by the following equation.

[0009] _{UB = W D · | V UB} | / | V AV | ......... (1) However, W _D: dummy weight weight _{| V UB | = (x UB} 2 + y UB 2) 1/2 ......... (2) Also, | V _AV | = (| V ₀ | + | V ₉₀ | + | V ₁₈₀ | + | V ₂₇₀ |) / 4 (3) The balance angle Θ _B is obtained by the following equation (4). Can be

Θ _B = Θ _U ± 180 ° (4) where Θ _U = tan ^-1 (y _UB / x _UB ) (5) Therefore, the balance of the weight UB at the position of the angle Θ _B Attaching weights will help balance the tires.

[0011]

However, in the conventional tire balance measuring device, the peak value of the power spectrum at the primary rotational frequency is recorded by a pen recorder, and the operator can monitor the fluctuation state of the spectrum peak. While observing, it was judged that the measurement was completed when it was considered to have stabilized to the constant value, and this was notified to the driver of the vehicle on the chassis dynamo.

[0012] Therefore, whether the fluctuation of the peak value is stabilized to a constant value largely depends on the experience and intuition of the operator, the judgment criterion differs for each operator, the measurement result tends to vary, and the accurate unbalanced weight can be obtained. And the measurement of the position was difficult. In addition, two workers, a worker who observes the pen recorder and a driver of the vehicle, require a lot of man-hours and work efficiency is poor.

The present invention has been made in view of such a problem, and it has been possible to automatically perform a portion which has been conventionally judged by a human to accurately measure an unbalanced weight and position, and to reduce the number of man-hours. It is an object of the present invention to provide a tire balance measuring device capable of improving the working efficiency by reducing the load.

[0014]

Means for Solving the Problems] The problems tire balance measuring apparatus according to the present invention sac Chi請 Motomeko 1 resolve is as shown in FIG. 1, a plurality of positions set in advance, predetermined U
Measure the tire rotation balance while replacing the eight.
The predetermined weight is in a predetermined location.
A rotation detecting means for detecting at least one of the rotational speed of the right and left tires mounted on a vehicle in a state attached to the
Acceleration detecting means mounted on a rotation support portion of the left and right tires with a predetermined weight attached to a predetermined location and detecting vibration of the support portion as acceleration; Time to calculate next frequency
A rolling primary frequency calculating means, and analyzing means for frequency analyzing a signal of the acceleration detecting means, obtained by the frequency analysis
It was the time of the acceleration amplitude in the rotation primary frequency band
Against to determine the amount of change is a predetermined value or near previously set, put to the weight attachment point at that time
Determining means that the detection of the tire rotation balance state has been completed, and the determining means determines that all of the plurality of locations have been detected.
Detection of tire rotation balance when weights are attached
When the acceleration is completed, the acceleration amplitude value changes with time.
It is characterized in that a processing means for calculating a <br/> tire rotation balance weight and balance position with reduction amount.

According to a second aspect of the present invention, in the tire balance measuring device, the analyzing means frequency-analyzes a signal from the left and right tire acceleration detecting means and calculates a tire acceleration power spectrum as the acceleration amplitude value. This
Of the primary rotation frequency of the tire acceleration power spectrum
Vibration takes the value and the average value thereof crests of temporal variation the acceleration
And means for calculating a change amount with respect to time of width values, the determining means determines that at least one of the temporal change amount of the crests average of the left and right tire acceleration power spectrum falls below a predetermined value And the Ue at that time
Detection of tire rotation balance condition
Means for completing the job , wherein the predetermined means includes a plurality of items.
Tire rotation variation with weight attached at all locations
When the detection of Nsu state is completed, and is characterized in that it comprises means for calculating the said tire rotation balance weight and balance position by using the value of the peak portion of the temporal variation of the tire acceleration power spectrum .

In the tire balance measuring device according to a third aspect of the present invention, the analyzing means frequency-analyzes the signal of the left and right tire acceleration detecting means to calculate a tire acceleration power spectrum as the acceleration amplitude value. This
Of the primary rotation frequency of the tire acceleration power spectrum
And the difference between the value of the peak portion of the time-dependent fluctuation and the value of the peak portion detected last time with the change amount of the acceleration amplitude value with respect to time.
And means for to operation, said determining means determines that at least one of the difference of the difference between the values of the peak portions of the left and right tire acceleration power spectrum falls below a predetermined value
The tire rotation bar at the weight attachment point at that time.
Means for determining that the lance state has been detected , wherein the predetermined means is a state in which the weights are attached at all of the plurality of locations.
When the detection of the tire rotation balance state in is completed,
Of the time variation of the tire acceleration power spectrum
The tire rotation balance weight and balance position using the values
It is characterized in further comprising means for calculating and.

According to a fourth aspect of the present invention, in the tire balance measuring device, the analyzing means frequency-analyzes a signal of the left and right tire acceleration detecting means and calculates a tire acceleration power spectrum as the acceleration amplitude value. This
Of the primary rotation frequency of the tire acceleration power spectrum
Kicking the crest value and therewith valley value and the successive average of the fluctuation obtained by the temporal variation find the center value, the difference the acceleration amplitude value of the central value and the previous calculated center value On time
Means for calculating as a change amount with respect to the weight , wherein the determination means determines that at least one of the differences between the center values of the left and right tire acceleration power spectra has become equal to or less than a predetermined value , and the weight at that time is determined. At the mounting point
Means for determining that the ear rotation balance state has been detected , wherein the predetermined means comprises a way at all of the plurality of locations.
Detection of the tire rotation balance with the
When the, is characterized in that it comprises means for calculating the said tire rotation balance weight and balance position by using the value of the peak portion of the time-varying <br/> movement of the tire acceleration power spectrum.

In the tire balance measuring device according to a fifth aspect of the present invention, the discriminating means includes means for instructing termination of the detection of the acceleration signal when the discrimination is completed. .

[0019]

According to the tire balance measuring device of the present invention, a predetermined weight is attached to a predetermined location.
In this state, the vibration of the rotation support portions of the left and right tires mounted on the vehicle is detected as acceleration and
The rotation speed is detected, and the rotation frequency of the tire is determined from the rotation speed.
And calculate the frequency of the detected acceleration,
If it is determined that the amount of change in the acceleration amplitude value with respect to time in the rotation primary frequency range obtained by the frequency analysis is equal to or near a predetermined value set in advance ,
Detection of tire balance condition at weight attachment point
When the weight is completed, this weight is
Repeat the above steps while
When the detection of the ear balance state is completed, the acceleration amplitude
Since the tire rotation balance weight and the balance position are calculated using the amount of change of the value with respect to time , the frequency-analyzed signal of the acceleration detecting means , that is, the rotation 1 of the acceleration amplitude value, is calculated.
The amount of change over time in the next frequency range is quantified.

According to the tire balance measuring device of the present invention, the acceleration amplitude is obtained by the frequency analysis.
The rotation 1 of the tire acceleration power spectrum as a value
Wherein the average value of mountain portion of the temporal variation in the next frequency pressurized
Calculated as the change amount with respect to time of the velocity amplitude value, the amount of change in crest average value of the data <br/> tire acceleration power spectrum to determine that it is now less than a predetermined value, the weight at that time
Detection of the tire balance state at the mounting location is completed
Tire balance at all weight attachment points
After the state of the discovery is complete, on the basis of the value of the peak portion of the tire acceleration power spectrum variation, it calculates a the tire rotational balance weight and balance position.

According to the tire balance measuring device of the present invention, the acceleration amplitude is obtained by the frequency analysis.
The rotation 1 of the tire acceleration power spectrum as a value
The difference between the peak value of the temporal change at the next frequency and the previous value
Calculated as a change amount of the acceleration amplitude value with respect to time ,
The difference between the value of the peak portion of the tire acceleration power spectrum is determined that it is now less than a predetermined value, the weight at that time
Detection of the tire balance state at the mounting location is completed
Tire balance at all weight attachment points
After the state of the discovery is complete, on the basis of the value of the peak portion of the tire acceleration power spectrum variation, it calculates a the tire rotational balance weight and balance position.

According to the tire balance measuring device of the present invention, the acceleration amplitude based on the frequency analysis is obtained.
The rotation 1 of the tire acceleration power spectrum as a value
The difference between the peak value and the valley value of the temporal variation at the next frequency from the previous value of the center value of the variation is calculated at the time of the acceleration amplitude value.
Calculated as the change amount for between, that difference in the center value of the tire acceleration power spectrum falls below a predetermined value <br/> to determine tire in weight attachment point at that time
It is assumed that the detection of balance has been completed, and all
Detection of the tire balance at the point where the
Et al., The tire acceleration power crest value of spectrum variation
Based on, for calculating the said tire rotation balance weight and balance position.

According to the tire balance measuring device of the present invention, when the determining means completes the determination, an instruction to terminate the detection of the acceleration signal is issued.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 2, the wheel 2 on which the tire 1 is mounted is fastened to the hub 3 mounted on the spindle 6 by bolts and nuts, as shown in FIG. The spindle 6 is connected to and supported by the strut 4 and the suspension lower arm 5. A longitudinal acceleration sensor 7 is attached to the spindle 6 by bonding or the like. The acceleration sensor 7 detects longitudinal vibration caused by imbalance of the tire 1 or the like, and generates an acceleration detection signal corresponding to the detected value. Output.
A reflection tape 8 is adhered to the tire 1 or the wheel 2, and reflected light from the reflection tape 8 is incident on an optical fiber sensor 10 provided to face the reflection tape 8. 10 outputs an ON / OFF electric signal of one pulse per one rotation of the wheel.

The acceleration detection signal is amplified by the amplifier 11 and input to the main body 12 of the analyzer. The ON / OFF signal of the optical fiber sensor 10 is amplified by an optical fiber sensor amplifier 13 and
2 is input. The remote switch 9 is connected to the analyzer main body 12. As shown in FIG. 4, a microcomputer 14 for performing main operations, recording, and reading, an A / D converter 15 for A / D converting a signal input to the microcomputer 14, An anti-aliasing filter 16 for cutting high-frequency components of the acceleration detection signal from the acceleration sensor 7; an interface circuit 17 for shaping the waveform between the microcomputer 14 and the remote switch 9; Liquid crystal display 1 to display
8, a printer 19 and the like. As shown in FIG. 3, the analyzer main body 12 is provided with a signal input terminal 13a from the optical fiber sensor amplifier 13, a signal input terminal 11a from the amplifier 11, and a power switch 25.

The remote switch 9 includes a rotary switch 20 for inputting a voltage proportional to the weight of the dummy weight 14 to the A / D converter 15 when the weight of the dummy weight 14 is selected, and a start switch 2 for instructing the start of sampling.
1. There are provided a cancel switch 22 for canceling sampling and calculation, a reset switch 23 for initializing an analysis program, and a lamp 24 which is turned on at the end of measurement.

Next, the operation of the analyzer main body 12 in this embodiment will be described. In this embodiment, as shown in FIG. 7, a temporal variation of a power spectrum as a tire acceleration amplitude value obtained by performing a fast Fourier transform analysis of a longitudinal acceleration detection value is obtained, and a peak as a variation with respect to the time is obtained. When the amount of change in the partial average value is equal to or less than a predetermined value,
Tire balance at the place where the dummy weight is attached at that time
It is assumed that the status detection has been completed, and this is
The tire rotation balance weight and its position are repeatedly calculated at the location where the dimmy weight is attached . Then, when the power switch 25 is turned on, the apparatus is in an operating state, and measurement and calculation are performed according to a program written in the memory of the microcomputer 14. The main routine shown in the flowchart of FIG. 5 is written in the memory in advance.

First, in step S1, the start switch 2
1 is checked, and if the switch 21 is ON, data sampling is started at a predetermined cycle (for example, 15.6 ms). Then, the process proceeds to step S2, where the rotation detection signal from the optical fiber sensor 10 is output. The data is read by the I / O port of the microcomputer 14, and then, in step S3
To the low level of the voltage of the rotation detection signal and H
A change point (edge) of the high level is detected and, for example, Lo
The rotation period T _N from the rise from w to High to the next rise is calculated, and in the next step S4, the average value T _AV of these rotation periods is calculated.

Next, in step S5, an acceleration detection signal from the longitudinal acceleration sensor 7 mounted on the left and right spindles 6 is read, and this acceleration detection signal is A / D converted and stored in a predetermined memory area of the microcomputer 14. I do. Then the number of data of the acceleration detection signal and proceeds to step S6 fast Fourier transform (FFT) a predetermined number necessary for the analysis, it is determined whether or not a e.g. N _S = 256 pieces store data number N _S is predetermined If it does not reach the number 256 data sampling of the predetermined period shifts to the step S2 is repeated, the number of data N _S is a predetermined number of 256
If the number has been reached, the process proceeds to step S7.

[0030] In the next step S7, the rotational primary frequency f ₁ is calculated by the following equation (6) from the mean value T _AV of the rotation cycle. f ₁ = 1 / T _AV (6) Then, the flow shifts to step S8 to analyze the acceleration detection signal of the left tire among the acceleration detection signals stored in the memory area, and then shifts to step S9. This F
From the left front longitudinal acceleration power spectrum distribution obtained by the FT analysis, a left power spectrum value P _LN at the rotation primary frequency f ₁ is obtained. Similarly proceeds to step S10 to FFT analysis acceleration detection signal of the right tires, we obtain the right power spectrum values P _RN in the rotating primary frequency f ₁ of the right tire then goes to step S11.

Then, the process proceeds to step S12 to execute the above-described steps.
Left power spectrum value P obtained in step S9_LNAnd the previous calculation
Left power spectrum value P_LOΔP_LCalculate
You. At this time, from the memory of the microcomputer 14
The difference ΔP of the left power spectrum value recorded in the previous calculation
_LOIs read in advance. Next, the process proceeds to step S13 and the left
Power spectrum value difference ΔP_LIs determined, and ΔP_L
If> 0, left power spectrum value P_LNIs increasing
And the process moves to step S16. On the other hand, ΔP_L≤
If 0, left power spectrum value P_LNIs decreasing
Then, the process proceeds to step S14, and the previous left power spectrum
Difference ΔP_LOIs determined, and ΔP _LO> 0
If left power spectrum value P_LNChanged from increase to decrease
Judgment is the peak of power spectrum fluctuation, and the next step
In step S15, the current left power spectrum value P_LNThis time
Yamabe P_LMAAnd the previous Yamabe P_LMATo Yamabe P_LMAOAs
Update recording is performed, and the process proceeds to step S16. Also before
In step S14, ΔP_LOIf ≤0, pull last time
Subsequently, the left power spectrum value P_LNIs determined to be on the decline
Then, the process proceeds to step S16.

In this step S16, the aforementioned step S1
The difference ΔP _R between the right power spectrum value P _RN obtained in step 1 and the right power spectrum value P _RO obtained in the previous calculation is calculated. At this time, the difference ΔP _RO of the right power spectrum value recorded in the previous calculation is read from the memory of the microcomputer 14. Next, the flow shifts to step S17 to determine the sign of the difference ΔP _R between the right power spectrum values. If ΔP _R > 0, it is determined that the right power spectrum value P _RN is increasing, and the flow shifts to step S20. On the other hand, if ΔP _R ≦ 0, it is determined that the right power spectrum value P _RN is decreasing, and the flow shifts to step S18 to determine the sign of the previous difference ΔP _RO between the right power spectrum values, and ΔP _RO > 0. If so, it is determined that the right power spectrum value P _RN is the peak of the power spectrum fluctuation that has changed from increasing to decreasing, and in the next step S19, the current right power spectrum value P _RN is set as the current peak P _RMA , The previous peak P _RMA is recorded as the peak P _RMAO , and the _{process proceeds} to step S20. If ΔP _RO ≦ 0 in step S18, it is determined that the right power spectrum value _PRN is continuously decreasing during the previous calculation, and the process proceeds to step S20.

In this step S20, the previous peak average value P _{LMAVO of the} left power spectrum fluctuation and the current peak P _LMA
Then, the _{left peak} average value P _LMAV is calculated. Although there are various methods for this calculation, in this embodiment, a half value P _LMAVO / 2 of the previous peak average value and a half value P _LMA / of the current peak portion are used.
Adding the 2 and left angle portions mean P _LMAV and, then proceeds to step S21 to calculate the difference [Delta] P _LMAD between the previous left angle section average value P _LMAVO and the current left angle section average value P _LMAV.

Next, the flow shifts to step S22, where the right power
The previous peak average value P of the fluctuation of the spectrum _RMAVOAnd this time Yamabe
P_RMAAnd the right peak average value P_RMAVIn step S20
And then proceed to step S23
Previous right peak average value P_RMAVOAnd the right peak average value P of this time
_RMAVΔP_RMADIs calculated. Next, in step S24
To the absolute value of the difference between the left peak average values | ΔP_LMAD|
Predetermined predetermined value α₁Judge whether it is greater than
| ΔP_LMAD|> Α₁If so, proceed to step S2
To repeat the above flow chart, | ΔP_LMAD| ≦ α
₁If so, the process proceeds to step S25.

In step S25, the right mountain part average value is calculated.
Absolute value of the difference | ΔP_RMAD| Is a predetermined value α set in advance₁
Is greater than or equal to | ΔP_RMAD|> Α₁That
If the process proceeds to step S2,
Repetition, | ΔP_RMAD| ≦ α ₁If so, step S26
Move to In the next step S26, the left mountain part average value
Absolute value of the difference | ΔP_LMAD| Also the difference between the right peak average value
Vs. | P_RMAD| Is also a predetermined value α₁Smaller than the left
The peak of the peak value fluctuation of the right power spectrum is asymptotically low.
It is determined that the measurement has been completed.
Outputs a signal to turn on the lamp 24 and turns on the lamp 24
And let the operator perceive the end of the measurement.

Next, the processing shifts to step S27, where the counter C
₁ to "1" is added (initial value is "0"), then proceeds to step S28 proceeds to step S29 if the counter C ₁ = 1, the position of the dummy weights in this step S29 0 ° Assuming that the measurement in the state of being attached to the end is completed, the peak values P _LMA and P _{RMA of the} left and right power spectrum fluctuations are recorded in the memory of the microcomputer 14 as the peak values P _L0 and P _R0 of 0 °, and the step S
Then, the process returns to 1 to wait for the start switch 21.

Next, a dummy weight is set at a position of 90 °.
When the start switch 21 is turned on, the step
From step S1 to step S26, measure in the same manner as above.
The end lamp 24 is turned on. And the step S2
7 and the counter C ₁When "1" is added to
The counter C₁= 2, so steps S28 and S3
0, and the process shifts to the step S31.
Assume that the measurement is completed with the
Left and right powers calculated by this flowchart
Peak value P of the spectrum fluctuation_LMA, P_RMAIs 90 °
Value P_L90, P _R90As the microcomputer 14
It is recorded in the memory and returns to step S1 to start
Switch 21 wait state.

Next, when the dummy weight is changed to the position of 180 ° and the start switch 21 is turned on, the measurement end lamp 24 is turned on in the same manner as described above in steps S1 to S26. And the step S
Since 27 is "1" in the counter C ₁ goes to the the counter C ₁ = 3 when summed, step S28, S
After going through steps S30 and S32 to step S33, the values P _LMA and P _RMA of the peaks of the left and right power spectrum fluctuations calculated by the present flowchart are determined assuming that the measurement with the dummy weight attached at the 180 ° position has been completed. Is 18
The peak values P _L180 and P _{R180 at} 0 ° are recorded in the memory of the microcomputer 14, and the process returns to step S1 to wait for the start switch 21.

Next, when the dummy weight is changed to a position of 270 ° and the start switch 21 is turned on, the measurement end lamp 24 is turned on in the same manner as described above in steps S1 to S26. And the step S
Since 27 is "1" in the counter C ₁ shifts to become when summed with the counter C ₁ = 4, step S28, S
After going through steps S30 and S32 to step S34, the values P _LMA and P _RMA of the peaks of the left and right power spectrum fluctuations calculated by the present flowchart are determined assuming that the measurement with the dummy weight attached at the position of 270 ° is completed. Is 27
The peak values P _L270 and P _{R270 at} 0 ° are recorded in the memory of the microcomputer 14 and the subroutine shown in FIG. 6 is programmed to calculate the balance weight and the position of the tire in step S35. ₁ is reset to "0", and the program is initialized. On the other hand, the worker attaches the displayed balance weight to the displayed position, and ends a series of operations.

[0040] In the flowchart of FIG. 5, step S2 to S4, S7 corresponds to the arithmetic means of the present invention, the step S5, S6, S8 ~S11 corresponds to the analyzing means, step S 12 ~S26 said Steps S27 to S36 correspond to processing means. Next, a subroutine shown in the flowchart of FIG. 6 programmed as step S35 of FIG. 5 will be described.

First, in step S37, a dummy wafer is set.
Signal according to the select position of the light setting switch 20
Converted by the A / D converter 15 and a dummy
Weight weight W_DAnd proceed to the next step S38.
Step S29 of the flowchart of FIG.
Peak value P of left power spectrum calculated in S33 _L0
And P_L180From the half value of the difference in the Y-axis direction shown in FIG.
Imbalance weight P_LYAnd then proceed to the next step S39.
Step S31 of the flowchart of FIG.
Peak value P of the left power spectrum calculated in S34
_L90And P_L270From the half value of the difference in the X-axis direction shown in FIG.
Unbalance weight P_LXIs calculated.

Next, the process proceeds to step S40, where the magnitude V _L of the left unbalance vector is calculated from the unbalance weight P _{LY in} the Y-axis direction and the unbalance weight P _{LX in the} X-axis direction by the following equation (7). Calculating a ^{_{V L = (P LY 2 +}} P LX 2) 1/2 ......... (7) then the average value P _L4 of the peak value P _L0 to P _{L2 70} of the left power spectrum and proceeds to step S41. Then, the process proceeds to step S42, wherein the weight W of the dummy weight is obtained.
_D , the left imbalance vector magnitude V _L , and the average value P _{L4 of the} left power spectrum peak values are used to calculate the left unbalance weight B _{L according} to the following equation (8).

B _L = W _D · V _L / P _L4 (8) Next, the flow shifts to step S43 to _{calculate the} unbalance weight P _{LY in the} Y-axis direction and the unbalance weight P _{LX in} the X-axis direction. The angle Θ _LU is calculated from the absolute value according to the following equation (9). ^{_{Θ LU = tan -1 (| P}} LY | / | P LX |) ......... (9) then unbalanced weight of the Y-axis direction and proceeds to step S44 P _LY and the X-axis direction of the unbalanced weight P _From the sign (±) of _LX, the angle Θ _LU is 1 on the graph shown in FIG.
4 quadrant from quadrant (counterclockwise) to determine the presence in the quadrant of the throat, the left unbalance angle theta _LU legitimate from between this and the angle theta _LU 'seek, the left unbalance angle theta _LU'
The left balance angle _{LB LB at} which the balance weight on the opposite side of 180 ° should be attached is calculated by the following equation (10).

Θ _LB = Θ _LU '± 180 ° (10) In this case, if the left unbalance angle Θ _LU ' is 180 ° or more, the left balance angle Θ _LB becomes Θ _LB = Θ _LU '-180 °. .. (10) ', and if the left unbalance angle ° _LU ' is 180 ° or less, the left balance angle Θ _LB is obtained by ＋ _LB = Θ _LU '+ 180 °.

Next, the process proceeds to step S45, and the same as above is performed.
And the peak value P of the right power spectrum_R0And P_R180of
From the half value of the difference, the unbalance weight in the Y-axis direction shown in FIG.
Quantity P _RYIs calculated, and the process proceeds to the next step S46, where the right power
-Peak value of spectrum P_{R9 0}And P_R270Half the difference between
From the unbalance weight P in the X-axis direction shown in FIG._RXTotal
Calculate.

[0046] Then the size V _R of the transition to the Y-axis direction of the unbalanced weight P _RY and the X-axis direction of the right unbalance vectors from unbalanced weight P _RX in step S47 is calculated by the following Expression 11. Calculating the ^{_{V R = (P RY 2 +}} P RX 2) 1/2 ......... (11) then the average value P _R4 of the right power peak value P _R0 to P _{R2 70} of the spectrum shifts to step S48. Then, the process proceeds to step S49, where the weight W of the dummy weight is obtained.
_D, and calculates the size V _R, the following 12 formula right unbalance weight B _R from the mean value P _R4 of the peak value of the right power spectrum of the right unbalance vectors.

B _R = W _D · V _R / P _R4 (12) Next, the process proceeds to step S50, where the absolute value of the unbalance weight P _{RY in the} Y-axis direction and the unbalance weight P _{RX in} the X-axis direction is _calculated. The angle _{RU RU} is calculated from the value by the following equation (13). Θ _RU = tan ⁻¹ (| P _RY | / | P _RX |) (13) Next, the process proceeds to step S51, where the unbalance weight P _{RY in the} Y-axis direction and the unbalance weight P in the X-axis direction are set. _From the sign (±) of _RX , it is determined in which quadrant the angle _{RU RU} is located to determine a regular right unbalance angle Θ _RU ′, and the balance on the opposite side of this right unbalance angle バ ラ_ンス_RU ′ by 180 ° is determined. Right balance angle to which weight should be attached ウ エ_RB below 14
It is calculated by the formula.

Θ _RB = Θ _RU '± 180 ° (14) In this case, if the right unbalance angle _{RU RU} ' is 180 ° or more, the right balance angle Θ _RB becomes Θ _RB = Θ _RU '-180 °. (14) ', and if the right unbalance angle Θ _RU ' is 180 ° or less, the right balance angle _{RB RB} is obtained by Θ _RB = Θ _RU '+ 180 ° (14) ".

Then, the flow shifts to step S52, where the left balance weight B _L , the left balance angle Θ _LB , the right balance weight B
_R and the right balance angle Θ _RB are displayed and printed on the liquid crystal display 18 and the printer 19, and the process returns to the main routine to complete a series of unbalance calculations. Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, FIG.
As shown in the above, the variation with time of the power spectrum as the tire acceleration amplitude value is obtained, and the amount of change with respect to the time is obtained.
Then , the difference between the previous mountain part and the current mountain part is directly calculated, and when the difference becomes equal to or less than a predetermined value ,
Of the tire balance at the place where the dummy weight is attached
It is assumed that detection has been completed, and this is
The tire rotation balance weight and its position are repeatedly calculated at the place where the mee weight is attached .

The main device of this embodiment is the same as that of the first embodiment, except for the main routine written in the microcomputer 14. The flowchart is shown in FIG. 8, but steps S1 to S19 in FIG. 8 are the same as steps S1 to S19 in FIG. 5, and steps S27 to S36 are steps S27 to S3 in FIG.
6 and only steps S53 to S57 are different. In step S35, a subroutine similar to that of FIG. 6 is written.

In step S53, the peak P of the current left power spectrum fluctuation calculated in the same manner as in the first embodiment.
Subtract the previous peak P _LMAO from _LMA and calculate the difference ΔP between both left peaks.
Calculate _LMD . Next, the processing shifts to step S54 to change the right peak P _RMA of the right power spectrum variation from the previous peak P _RMA.
RMAO is subtracted to calculate the difference ΔP _RMD between the right and left peaks.

Then, the flow shifts to step S55, where the absolute value | ΔP _LMD | of the difference between the left mountain portions is set to a predetermined value α ₂
Determines whether larger or not, | ΔP _LMD |> Repeat the flowchart goes to alpha ₂ a long if step S2, | shifts to ≦ alpha ₂ a long if step S56 | ΔP _LMD. The absolute value of the difference of the right angle portion in step S56 | ΔP _RMD | it is determined whether the set is greater than a predetermined value alpha ₂ in advance, | ΔP _RMD |> α proceeds to step S2 if ₂ And repeat the above flow chart,
| [Delta] P _RMD | if ≦ alpha ₂ proceeds to step S57.

In the next step S57, the absolute value | ΔP _LMD | of the difference between the left peaks is also the absolute value | ΔP of the difference between the right peaks.
_RMD | since even smaller than the predetermined value alpha _2, the lighting end of measurement lamp 24 of the first embodiment similarly to the remote switch 9 crests of the peak value variation of the left and right power spectrum is determined to asymptotically stable A signal is output to turn on the lamp and the operator is notified of the end of the measurement.

Next, a third embodiment of the present invention will be described with reference to FIG. The data as shown in FIG. 11 in this embodiment
Temporal variation of power spectrum as ear acceleration amplitude
The calculated, as a change amount with respect to that time, obtains the center value of the range from the value and the value of the valley at the crest, when the amount of change in the central value becomes equal to or less than a predetermined value set in advance, at that time
Check the tire balance at the place where the dummy weight is attached.
Has been completed, and this is
-The tire rotation balance weight and its position are repeatedly calculated at the place where the weight is attached .

The main device of this embodiment is the same as that of the first embodiment, except for the main routine written in the microcomputer 14. The flowchart is shown in FIG. 10, but steps S1 to S11 in FIG. 10 are the same as steps S1 to S11 in FIG. 5, and steps S27 to S36 are steps S27 to S36 in FIG.
36, and only the steps S58 to S74 are different. In step S35, a subroutine similar to that of FIG. 6 is written.

In step S58 shown in FIG.
Left longitudinal acceleration power spectrum obtained in the same manner as in the example
Torr value P_LNAnd the left power spectrum value P from the previous calculation_LOWhen
Difference ΔP between_LIs calculated. At this time,
Left power recorded in the previous calculation from the memory of the computer 14
-Spectrum value difference ΔP_LOIs read in advance. Next,
Proceeding to step S59, the left power spectrum value difference ΔP_L
Is determined, and ΔP_L> 0 if left power spectrum
Value P_LNIs determined to be increasing and the process proceeds to step S60.
And the difference ΔP of the previous left power spectrum value_LOThe sign of
And ΔP_LOIf> 0, left power spectrum fluctuation is before
It is determined that the number of times has been increasing since the first time, and step S6 is performed.
Move to 4. In step S60, ΔP
_LOIf ≦ 0, it is assumed that a valley exists during the spectrum fluctuation.
Then, the process proceeds to the next step S61, where the current spectrum value
P_LNTo the valley value P_LMiAnd update it in memory as
Valley value P_LMiAnd the previous peak value P_LMAHalf of the sum of
(P_LMi+ P_LMA) / 2 is the left fluctuation center value P_LMCalculated as
Then, control goes to the step S64.

On the other hand, in step S59, ΔP _L
≦ If 0 is left power spectrum value P _LN is determined to be in reduced, migrate to determine the sign of the difference [Delta] P _LO of the previous left power spectrum value in step S62, the previous if [Delta] P _LO ≦ 0 Subsequently, it is determined that the left power spectrum value P _LN is decreasing, and the flow shifts to the step S64. If ΔP _LO > 0 in step S62, it is determined that a peak exists during the spectrum fluctuation, and in the next step S63, the current left power spectrum value P _{LN is changed} to the peak value P _LN.
It is updated and recorded in the memory as _LMA, and the half value (P _LMi +) of the sum of this peak value P _LMA and the previous valley value P _LMi
P _LMA ) / 2 is calculated as the left fluctuation center value P _LM , and the flow shifts to step S64.

Step S64 is the same as in the first embodiment.
Front-rear acceleration power spectrum value P obtained by_RNWhen
Right power spectrum value P from previous calculation_ROΔP
_RIs calculated. At this time, the microcomputer 14
Right power spectrum recorded from the previous calculation from memory
Value difference ΔP_ROIs read in advance. Next, in step S65
Shift to right power spectrum value difference ΔP_RDetermine sign of
And ΔP_R> 0, right power spectrum value P_RNIs increased
Is determined to be in progress, the process proceeds to step S66, and
Power spectrum value difference ΔP_ROIs determined, and ΔP_RO
If> 0, the right power spectrum fluctuation continues from the previous time
And the process proceeds to step S70.
You. In step S66, ΔP _RO≤0
If a valley exists during the spectrum fluctuation,
Proceeding to step S67, the current spectrum value P_RNThe valley
Value of P_RMiIs recorded in the memory as the value P
_RMiAnd the previous peak value P_RMAAnd half of the sum (P_RMi+
P_RMA) / 2 is the central value of the right fluctuation P_RMCalculated as
The process moves to step S70.

On the other hand, in step S65, ΔP _R
If ≦ 0 right power spectrum values P _RN is judged to be in reduced, migrate to determine the sign of the difference [Delta] P _RO previous right power spectrum values in step S68, the previous if [Delta] P _RO ≦ 0 Then, it is determined that the right power spectrum value P _RN is decreasing, and the flow shifts to step S70. If ΔP _RO > 0 in step S68, it is determined that a peak exists during the spectrum fluctuation, and in the next step S69, the current right power spectrum value P _{RN is changed} to the peak value P _R.
It is updated and recorded in the memory as _RMA, and the half value (P _RMi +) of the sum of the peak value P _RMA and the previous valley value P _RMi
P _RMA ) / 2 is calculated as the right fluctuation center value P _RM , and the flow shifts to step S 70.

[0060] The step S70 in the previous variation central value P from the calculated current left fluctuation center value P _LM as
Subtract _LMO and calculate their difference ΔP _LM . Next, the process proceeds to step S71, in which the previous right fluctuation center value P _RMO is subtracted from the current right fluctuation center value P _RM , and a difference ΔP _RM between them is calculated. Next, the flow shifts to step S72, where the absolute value | ΔP _LM | of the difference between the left fluctuation center values is set to a predetermined value α ₃
Determines whether larger or not, | ΔP _LM |> α and migrate repeatedly the flowchart in ₃ a long if step S2, | ΔP _LM | if ≦ alpha ₃ proceeds to step S73.

[0061] The absolute value of the difference between the right change center value in step S73 | determines whether the set is greater than a predetermined value alpha ₃ in advance, | | [Delta] P _RM said long> alpha is ₃ | [Delta] P _RM transition to the step S2 repeatedly flowchart of the, | [Delta] P _RM | if ≦ alpha ₃ proceeds to step S74. In the next step S74, the absolute value | ΔP _LM | of the difference between the left fluctuation center values is also the absolute value | Δ of the difference between the right fluctuation center values.
P _RM | is smaller than the predetermined value α _3, the signal for turning on the measurement end lamp 24 of the remote switch 9 is determined similarly to the first embodiment, judging that the center value fluctuation of the left and right power spectrum has been asymptotically stabilized. Is output to turn on the lamp 24 to make the operator perceive the end of the measurement.

FIG. 12 shows the relationship between the predetermined values α _{1 to} α ₃ , that is, the fluctuation convergence range of the power spectrum value and the tire rotation imbalance weight. As is clear from this figure,
For example, when the convergence range is set to ± 0.5 dB, the measurement accuracy of the unbalanced weight increases, but the time required for the convergence determination increases. Conversely, if the convergence range is set to ± 2 dB, the measurement accuracy is reduced, but the time required for convergence determination is reduced. It can be seen that if the measurement error of the unbalance weight that is normally set is 8 g or less, the convergence range may be set to ± 2 dB.

It is not necessary to use each of the above embodiments alone, and by combining them, more accurate measurement can be performed. In each embodiment, the left and right tires are measured at the same time, but it is needless to say that the measurement for each tire is also possible. Further, in the above embodiment, the frequency analysis is performed by the FFT. However, the frequency analysis can be performed by, for example, a band-pass filter.

Further, in the above embodiment, the case where the microcomputer is applied as the main body of the analyzer has been described. However, the present invention is not limited to this, and the comparison circuit,
An electronic circuit such as an arithmetic circuit and a theoretical circuit may be combined.

[0065]

According to the tire balance measuring device of the present invention, a state in which a predetermined weight is attached to a predetermined position.
Vibration of the rotation supporting portions of the right and left tires mounted on a vehicle in state
Detects motion as acceleration and detects the number of rotations
And calculates the rotational primary frequency of the tire from the rotational speed
Along with frequency analysis of the detected acceleration and frequency analysis
If it is determined that the amount of change in the acceleration amplitude value with respect to time in the primary rotation frequency range obtained by the above is equal to or near a predetermined value set in advance , the weight at that time is determined.
When the detection of the tire balance state at the attachment point has been completed
Then, change the weight to the specified
Repeat for all tire weight baluns
When the detection of the acceleration state is completed,
Since the tire rotation balance weight and the balance position are calculated and displayed using the amount of change with respect to, the conventional,
The amount of change in the acceleration amplitude value over time in the primary frequency range of tire rotation, which relied on the experience and intuition of the operator, is quantified, and the measurement of the balance weight and its position is not dispersed, enabling more accurate measurement. Become. In addition, the acceleration vibration in the primary rotational frequency range obtained by the frequency analysis
Since the operator does not need to observe the convergence state of the change of the width value with respect to time , the number of steps can be reduced and the working efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a basic configuration of a tire balance measuring device of the present invention.

FIG. 2 is a system diagram showing an embodiment of the tire balance measuring device of the present invention.

FIG. 3 is a schematic external view of a tire balance measuring device of the present invention.

FIG. 4 is a block diagram of the tire balance measuring device of the present invention.

FIG. 5 is a flowchart showing a main routine in a first embodiment of the tire balance measuring device of the present invention.

FIG. 6 is a flowchart showing a subroutine in the embodiment of the tire balance measuring device of the present invention.

FIG. 7 is an explanatory diagram for judging power spectrum fluctuation in the first embodiment of the tire balance measuring device of the present invention.

FIG. 8 is a flowchart showing a main routine in a second embodiment of the tire balance measuring device of the present invention.

FIG. 9 is an explanatory diagram for judging a power spectrum fluctuation in the second embodiment of the tire balance measuring device of the present invention.

FIG. 10 is a flowchart showing a main routine in a third embodiment of the tire balance measuring device of the present invention.

FIG. 11 is an explanatory diagram for determining a power spectrum fluctuation in the third embodiment of the tire balance measuring device of the present invention.

FIG. 12 is an explanatory diagram showing a relationship between a convergence value of power spectrum fluctuation and a tire rotation imbalance amount.

FIG. 13 is an explanatory diagram for calculating a tire rotation balance weight and its position.

FIG. 14 is a system diagram of a conventional tire balance measuring device.

FIG. 15 is an explanatory diagram of a tire rotation balance measurement procedure.

FIG. 16 is an explanatory diagram of a tire rotation pulse.

FIG. 17 is an explanatory diagram of longitudinal acceleration caused by tire rotational vibration.

FIG. 18 is an explanatory diagram of a power spectrum distribution obtained by frequency analysis of longitudinal acceleration.

FIG. 19 is an explanatory diagram of a peak value fluctuation of a power spectrum.

[Explanation of symbols]

1 is a tire, 2 is a wheel, 3 is a hub, 4 is a strut, 5 is a lower suspension arm, 6 is a spindle,
7 is an acceleration sensor, 8 is a reflection tape, 9 is a remote switch, 10 is an optical fiber sensor, 11 is an amplifier, 12 is an analyzer main body, 13 is an optical fiber sensor amplifier, 14 is a microcomputer, 15 is an A / D converter, 16
Is an anti-aliasing filter, 17 is an interface circuit, 18 is a liquid crystal display, 19 is a printer, 20 is a dummy weight rotary switch, 21 is a sampling start switch, 22 is a cancel switch, 23 is a reset switch, 24 is a measurement end lamp, 25 is a power switch

Claims (5)

(57) [Claims] A predetermined cue is provided at a plurality of predetermined locations.
Measure the tire rotation balance while replacing the eight.
The predetermined weight is in a predetermined location.
A rotation detecting means for detecting at least one of the rotational speed of the right and left tires mounted on a vehicle in a state attached to the
Acceleration detecting means mounted on a rotation support portion of the left and right tires with a predetermined weight attached to a predetermined location and detecting vibration of the support portion as acceleration; Time to calculate next frequency
A rolling primary frequency calculating means, and analyzing means for frequency analyzing a signal of the acceleration detecting means, obtained by the frequency analysis
It was the time of the acceleration amplitude in the rotation primary frequency band
Against to determine the amount of change is a predetermined value or near previously set, put to the weight attachment point at that time
Determining means that the detection of the tire rotation balance state has been completed, and the determining means determines that all of the plurality of locations have been detected.
Detection of tire rotation balance when weights are attached
When the acceleration is completed, the acceleration amplitude value changes with time.
Volume of the tire balance measuring apparatus characterized by comprising a processing means for calculating a <br/> tire rotation balance weight and balance position with. Wherein said analyzing means includes means for calculating a tire acceleration power spectrum as the acceleration amplitude value by frequency analysis of signals the right and left tire acceleration detecting means, this
Of the primary rotation frequency of the tire acceleration power spectrum
Vibration takes the value and the average value thereof crests of temporal variation the acceleration
And means for calculating a change amount with respect to time of width values, the determining means determines that at least one of the temporal change amount of the crests average of the left and right tire acceleration power spectrum falls below a predetermined value And the Ue at that time
Detection of tire rotation balance condition
Means for completing the job , wherein the predetermined means includes a plurality of items.
Tire rotation variation with weight attached at all locations
Claim detection Nsu state when completed, characterized by comprising means for calculating and said tire rotation balance weight and balance position by using the value of the peak portion of the temporal variation of the tire acceleration power spectrum 1 The tire balance measuring device according to the above. Wherein said analyzing means includes means for calculating a tire acceleration power spectrum as the acceleration amplitude value by frequency analysis of signals the right and left tire acceleration detecting means, this
Of the primary rotation frequency of the tire acceleration power spectrum
And the difference between the value of the peak portion of the time-dependent fluctuation and the value of the peak portion detected last time with the change amount of the acceleration amplitude value with respect to time.
And means for to operation, said determining means determines that at least one of the difference of the difference between the values of the peak portions of the left and right tire acceleration power spectrum falls below a predetermined value
The tire rotation bar at the weight attachment point at that time.
Means for determining that the lance state has been detected , wherein the predetermined means is a state in which the weights are attached at all of the plurality of locations.
When the detection of the tire rotation balance state in is completed,
Of the time variation of the tire acceleration power spectrum
The tire rotation balance weight and balance position using the values
2. The tire balance measuring device according to claim 1, further comprising means for calculating the following. Wherein said analyzing means includes means for calculating a tire acceleration power spectrum as the acceleration amplitude value by frequency analysis of signals the right and left tire acceleration detecting means, this
Of the primary rotation frequency of the tire acceleration power spectrum
Kicking the crest value and therewith valley value and the successive average of the fluctuation obtained by the temporal variation find the center value, the difference the acceleration amplitude value of the central value and the previous calculated center value On time
Means for calculating as a change amount with respect to the weight , wherein the determination means determines that at least one of the differences between the center values of the left and right tire acceleration power spectra has become equal to or less than a predetermined value , and the weight at that time is determined. At the mounting point
Means for determining that the ear rotation balance state has been detected , wherein the predetermined means comprises a way at all of the plurality of locations.
Detection of the tire rotation balance with the
When the claim 1, wherein further comprising means for calculating and said tire rotation balance weight and balance position by using the value of the peak portion of the time-varying <br/> movement of the tire acceleration power spectrum Tire balance measuring device. 5. The tire balance measuring device according to claim 2, wherein the determination means includes means for instructing termination of the detection of the acceleration signal when the determination is completed.