JP3207367B2 - Arithmetic circuit of tire FV machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an arithmetic circuit for a tire FV machine.

[0002]

2. Description of the Related Art Conventionally, tire RFV, LFV, LF
D, CONICITY etc. various FV (Force Va)
In order to test whether or not the tire FV machine for measuring the relationship (Ration) functions accurately, a master tire having various known FV values is actually measured by the FV machine, and the measured value is compared with the measured value. The accuracy was confirmed by comparing with a known FV value.

[0003]

However, when a master tire is used as described above, only rough measurement accuracy of the entire FV machine can be guaranteed. In addition, as an accuracy test of the analog arithmetic unit, although the output of the load cell could be calibrated, the analog arithmetic unit such as a SUB amplifier, a GAIN amplifier, a low-pass filter, and an A / D conversion circuit that processes dynamic data was used. The accuracy test could not be performed. In addition, since the master tire must be mounted on the FV machine and the FV machine must be operated in the automatic or manual mode, there is a problem that the workability of the inspection is deteriorated, it takes time, and the safety is poor. .

Therefore, the present invention solves the above-mentioned problems, and can easily and accurately inspect and calibrate the accuracy of an analog arithmetic circuit without operating a tire FV machine.
It is another object of the present invention to provide an arithmetic circuit for a tire FV machine with high safety.

[0005]

In order to achieve the above object, an arithmetic circuit of a tire FV machine according to the present invention comprises: a reference signal input means for inputting a reference signal to an analog arithmetic unit of the tire FV machine; An operation unit calculates the reference signal and outputs an output signal, which is input, calculates a detection value, and compares the detection value with a reference value of the reference signal to calculate an error of the analog operation unit. And a display processing means for displaying an error of the analog operation unit calculated by the comparison operation means on a display unit.

Further, the reference signal input means is configured to adjust the reference value of the reference signal in a plurality of steps, and the display processing means displays the error of the analog operation section at each reference value of the reference signal in the display section. Is preferably displayed. Further, the comparison calculation means is configured to determine whether or not the error of the analog calculation unit is within a range of an allowable error and to send a pass / fail determination result signal to the display processing means,
Preferably, the display processing means is configured to display the result of the pass / fail judgment on the display unit.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on the illustrated embodiments.

FIG. 1 shows the RFV, LFV and LF of the tire.
D, CONICITY, etc. FV (Force Vari)
1) shows a tire FV machine for measuring the tire FV, wherein 1 is a detection unit for detecting the FV of the tire to be measured,
Reference numeral 2 denotes a calculation circuit for calculating the FV signal detected by the detection unit 1 and checking and calibrating the accuracy of the analog calculation unit. Reference numeral 4 denotes a display unit comprising a display 5 and a printer 11. Reference numeral 6 denotes input means such as a keyboard. Is shown. The detection unit 1 exemplifies a case for RFV detection, and includes a TOP load cell 40, a BOT load cell 41, and load cell amplifiers 42 and 43 for amplifying analog signals from the load cells 40 and 41.

Thus, the arithmetic circuit {ie, arithmetic circuit 2} of the tire FV machine according to the present invention is provided with an analog arithmetic circuit 7 for performing an analog arithmetic operation on the signal sent from the detection unit 1.
And a digital operation circuit 9 that performs processing such as operation of signals sent from the analog operation circuit 7 and output to the display unit 4.
And a reference signal input means 3 for inputting a reference signal to the analog operation unit 8 (to be described in detail later) at the time of accuracy inspection / calibration of the analog operation circuit 7.

The analog operation circuit 7 is connected to the output side of the SUM amplifier 44 for adding and amplifying the signals from the load cell amplifiers 42 and 43 of the detection section 1 and calibrates the normal (normal measurement state). (Accuracy inspection / calibration state) and a changeover switch 45 having a terminal for outputting an analog signal s for sampling, and a SU when the changeover switch 45 is in a normal state.
An analog operation unit 8 connected to the M amplifier 44 and connected to the reference signal input means 3 at the time of calibration;
It includes a sampling synchronization means 47 for converting the analog signal s to the digital signal d ₁ for inputting at sampling synchronization pulses to the digital arithmetic circuit 9, a.

FIG. 2 is a graph for explaining the operation of the sampling synchronization means 47 at the time of calibration. The analog signal s is a sine wave. Thus, by sampling corresponding to amplitude of the analog signal s to the sampling synchronization pulses 48 ..., into a digital signal d _1. Note that the sampling synchronization pulses 48 are output at 128 pulses / second during calibration, and are output at 128 pulses / second during normal operation.
Pulse / rotary rotary encoder output.

Returning to FIG. 1, the analog operation unit 8
Is a SUB amplifier that subtracts a static component of a signal sent from the changeover switch 45 and extracts only a force variation component, and a GAIN that amplifies an FV component that is a minute voltage (for example, by a factor of 10).
Having an amplifier, a low pass filter for precision drop prevention due to the influence of high-order component (noise component), and A / D converter circuit for converting an analog FV signal to a digital signal d _2, a. The output side of the analog operation unit 8 is connected to the digital operation circuit 9, and the digital signal d ₂ is sent from the analog operation unit 8 to the digital operation circuit 9.

Next, as shown in FIG. 3, the reference signal input means 3 includes a line filter 13 connected to an external AC power supply 46 such as a household power supply and a noise filter connected to the output side of the line filter 13. A power supply unit 16 comprising a DC power supply 15 connected to an output side of the noise filter 14; a transmitting unit 17; and an output level (reference value) connected to the transmitting unit 17 and controlled by a level adjustment switch 21. A reference signal generating circuit 20 including a first amplifier 18 that can be adjusted in a plurality of stages and a second amplifier 19 connected to the output side of the first amplifier 18 and outputting a reference signal is provided. That is, the reference signal input means 3 is configured to be able to adjust the reference value of the reference signal in a plurality of steps.

Further, as shown in FIG. 4, the reference signal input means 3 is formed as a separate body accommodated in a casing 22, and a level adjusting switch 21 is provided on the outer surface of the casing 22.
And a power switch 23, a fuse 24, a pilot lamp 25, an anode terminal 26 for reference signal output, a cathode terminal 27, and a ground terminal 28 for grounding one side of a shielded wire of the signal cable for noise prevention. . Then, the reference signal input means 3 is connected to the analog operation circuit 7 by a signal cable 29 having a shield line (see FIG. 1).

Here, as shown in FIG. 5, the reference signal b output from the reference signal input means 3 is a sine wave (output from the 1 Hz transmission circuit). The peak value P of the sine wave is a voltage corresponding to a reference value (FV value) of six stages of 0, 10, 20, 30, 40, and 50 kgf. That is, the peak-to-peak value P can be adjusted in six steps by the level adjustment switch 21 described above. Note that F is an offset of the reference signal b, and the offset F is variable.

Next, as shown in FIG. 6, the digital operation circuit 9 receives the output signal which is obtained by calculating the reference signal in the analog operation section 8 and calculates a detection value. A comparison operation means for comparing the reference value of the reference signal with the reference value to calculate an error of the analog operation section;
And a display processing means 12 for displaying the information. Here, the comparison operation means 10 compares the reference signal from the reference signal input means 3 as an input and the detected value (measurement result) displayed on the display 5 as an output.
It is.

The comparison operation means 10 is configured to judge whether or not the error of the analog operation section 8 is within an allowable error range and to send a pass / fail judgment result signal to the display processing means 12. You. Further, the display processing means 12 is configured to display the result of the pass / fail judgment on the display unit 4 and to display the error of the analog operation unit 8 at each reference value of the reference signal on the display unit 4.
Is configured to be displayed. Actually, the digital operation circuit 9 is composed of a personal computer, and the accuracy inspection and calibration of the analog operation unit 8 are performed by software (calibration program). The pass / fail judgment is made, for example, when the peak-to-peak value P of the reference signal is 0, 10, 20, 30, 4
For each of the six levels of reference values (FV values) of 0 and 50 kgf, if the value is within the range of ± 0.5 kgf, it is judged as pass, and ± 0.5 kgf
If it is outside the range of kgf, it will be rejected.

If the changeover switch 45 is set to the normal state (returning to FIG. 1), the tire to be measured is set in the detecting section 1, and the tire FV machine is operated, the FV of the tire to be measured can be measured. . That is, the FV signal detected by the detection unit 1 is calculated by the analog calculation circuit 7, further processed by the digital calculation circuit 9, and the FV value is displayed on the display 5 of the display unit 4 and the printer 11. . At this time, the reference signal input means 3 is connected to the analog arithmetic circuit 7
Separate from

If the changeover switch 45 is switched to the calibration side, the accuracy test and calibration of the analog operation section 8 can be performed. The accuracy inspection / calibration method of the analog operation unit 8 will now be described with reference to the flowchart of FIG. First, the reference signal input means 3 is connected to the analog operation circuit 7 by a signal cable. Next, the changeover switch 45 is switched to the calibration side. Thereafter, it is determined whether or not the operation preparation of the printer 11 for printing the inspection result has been completed. If not, the determination is made again. If completed, the level adjustment switch 21 of the reference signal input means 3 is determined. Displays an instruction to select "0" on the display 5.

Then, after selecting "0" with the level adjustment switch 21 of the reference signal input means 3, a predetermined key (for example, a function key of f.1) of the input means 6 is pressed, and the analog operation unit calibration is performed. Start the program.
As a result, the reference signal output from the reference signal input means 3 is calculated by the analog calculation section 8 of the analog calculation circuit 7, and further, the calculation, determination and other processes are performed by the digital calculation circuit 9. Then, the calculation result is displayed (output) on the display 5 and the printer 11.

Thereafter, it is determined whether or not the inspection has been completed for all the reference values. If not, the reference value is manually increased by one step. That is, the level adjustment switch is set so that the reference value is increased by 10 kgf. Switch 21. Thereafter, a predetermined key of the input means 6 is pressed again to start a program for calibrating the analog arithmetic unit, and the digital arithmetic circuit 9 performs calculations, determinations and other processes, and displays the calculation results on the display 5 and the printer 11. Display (output).

Here, an example of the display on the display 5 is shown in FIG. In the figure, 30 is a date display section, 31 is a line to be inspected display, 32 is a judgment result display section for each reference value, 3
3, 34, and 35 are calculation result display sections for reference value, detected value, and error.
6 is an FV type display section, and 37 is an overall judgment result display section. Reference numeral 38 denotes a command display for setting the level adjustment switch 21. The reference value (reference value = 40 in the example) surrounded by the command display 38 (rectangular frame) indicates the level adjustment switch 21.
Is set and then a predetermined key of the input means 6 (not shown) is pressed, and the detected value, error, and judgment at the reference value = 40 are calculated and displayed on the display 5.

Thereafter, when it is determined that the inspection has been completed for all the reference values, it is determined whether the detected value is within a predetermined numerical range (in this case, within ± 0.5 kgf of the reference value) with respect to the reference value. Make a judgment. Specifically, the inspector judges the judgment result displayed on the display 5 or the printer 11 by looking at the judgment result. If it is determined that the value is out of the range, the calibration of the analog operation unit 8 is performed.

This determination and calibration are performed as follows. (a) If all the characteristic values of RFV, LFV and LFD are acceptable (within ± 0.5 kgf of the reference value), no calibration is required. (b) If all the characteristic values of RFV, LFV, and LFD have the same offset value, adjust the offset of the A / D conversion circuit. (c) If all characteristic values of RFV, LFV, and LFD have the same slope (gain) and a difference, the gain of the A / D conversion circuit is adjusted. (d) When each characteristic value has an error independently, (d-1) When the error value exceeds ± 0.5 kgf and is within ± 1.5 kgf, the offset and gain are set by the GAIN amplifier of each characteristic calculation circuit. Make adjustments. (d-2) If the error value exceeds ± 1.5 kgf, check the calculation accuracy of each of the SUB amplifier, the GAIN amplifier, and the low-pass filter, and finely adjust each. The adjustments (a) to (d) are performed by using a DC reference voltage generator and inputting a voltage signal output from the DC reference voltage generator to each amplifier.

After performing the above calibration, the reference value “0” is again set.
Inspection from to "50". Thereafter, when it is determined that the detected value is within a predetermined numerical range (within ± 0.5 kgf) with respect to the reference value, the changeover switch 45 is switched to the normal side. Then, the reference signal input means 3 is removed (the reference signal input means 3 is separated from the analog operation circuit 7).
Thus, the inspection of the analog operation unit 8 is completed.

Note that the detection unit 1 and the analog operation circuit 7
The accuracy test and calibration of the UM amplifier 44 are performed using a reference weight.

According to the arithmetic circuit of the tire FV machine, the accuracy inspection and calibration of the analog arithmetic unit 8 which cannot be performed by the conventional inspection method using the master tire can be performed.
It can be carried out. That is, the accuracy test and calibration can be individually performed for all analog circuits such as the SUB amplifier, the GAIN amplifier, the low-pass filter, and the A / D conversion circuit of the analog operation unit 8. In addition, since it is not necessary to use a master tire and it is not necessary to operate the detection unit 1, it is possible to save power and air consumption. And it is excellent in workability and safety. Further, accuracy inspection and calibration can be performed efficiently in a short time and with high accuracy.

Further, since the reference signal input means 3 is formed separately, it can be shared by a plurality of tire FV machines. Therefore, it is possible to make the measurement accuracy difference due to electrical factors extremely small. In addition, a personal computer can be used as the digital operation circuit 9 (comparison operation means 10 and display processing means 12), and calculation, determination, calibration, and the like can be performed by software. Therefore, the capital investment is small. That is, it is only necessary to add the reference signal input means 3, the changeover switch 45, the sampling synchronization means 47, and the calibration software to the conventional FV machine.

The present invention is not limited to the above-described embodiment, but may be modified in design. For example, the level adjusting switch 21 of the reference signal input means 3 may be adjustable in a plurality of stages other than six. For example, 4, 5, 7, or 8 levels may be used.

[0030]

The present invention has the following remarkable effects by the above-mentioned structure.

According to the arithmetic circuit of the tire FV machine according to the first aspect, the accuracy inspection and calibration of the analog arithmetic unit 8 which cannot be performed by the conventional inspection method using the master tire,
It can be carried out. In addition, (SU) of the analog operation unit 8
B amplifier, GAIN amplifier, low pass filter, A / D
Accuracy testing and calibration can be performed individually for all analog circuits (such as conversion circuits). In addition, since it is not necessary to use a master tire and it is not necessary to operate a detection unit to which the tire is attached, power and air consumption can be reduced, and workability and safety are excellent. Further, the accuracy inspection and calibration of the analog operation unit 8 can be performed efficiently in a short time and with high accuracy. Further, if the reference signal input means 3 is formed as a separate body and connected to an analog arithmetic circuit at the time of accuracy inspection, a plurality of tires F
Can be shared by V machines. In addition, it is possible to make the measurement accuracy difference due to electrical factors extremely small.

According to the arithmetic circuit of the tire FV machine according to the second aspect, the same effects as those of the first aspect can be obtained, and the accuracy inspection and calibration of the analog arithmetic section 8 can be performed with higher accuracy. .

According to the arithmetic circuit of the tire FV machine according to the third aspect, the same effect as that of the first or second aspect can be obtained, and whether the error of the analog arithmetic unit is within the allowable error range. Is displayed on the display unit, so that the accuracy inspection and calibration of the analog operation unit 8 can be performed more accurately in a shorter time.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a graph illustrating the operation of a sampling synchronization pulse.

FIG. 3 is a block diagram showing reference signal input means.

FIG. 4 is a front view showing the appearance of a reference signal input unit.

FIG. 5 is a graph illustrating a reference signal.

FIG. 6 is a block diagram of a main part.

FIG. 7 is a flowchart illustrating a method of checking and calibrating the accuracy of an analog operation unit.

FIG. 8 is a front view showing an example of a display on a display.

[Explanation of symbols]

 3 Reference signal input unit 4 Display unit 8 Analog operation unit 10 Comparison operation unit 12 Display processing unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01M 17/02 B60C 19/00

Claims (3)

(57) [Claims] 1. A reference signal input means 3 for inputting a reference signal to an analog operation section 8 of a tire FV machine, and an output signal which is obtained by calculating the reference signal in the analog operation section 8 and is detected. A comparison operation means 10 for calculating an error and comparing the detected value with a reference value of the reference signal to calculate an error of the analog operation section 8;
And a display processing unit (12) for displaying the error of the analog calculation unit (8) calculated in (10) on the display unit (4). 2. The reference signal input means 3 is configured to be able to adjust the reference value of the reference signal in a plurality of steps, and the display processing means 12 is configured to execute the analog operation unit 8 using each reference value of the reference signal.
The arithmetic circuit of the tire FV machine according to claim 1, wherein an error of the tire FV machine is configured to be displayed on the display unit 4. 3. The comparison calculation means 10 is configured to determine whether or not the error of the analog calculation unit 8 is within an allowable error range and to send a pass / fail determination result signal to the display processing means 12. The arithmetic circuit of the tire FV machine according to claim 1 or 2, wherein the display processing means (12) is configured to display a result of the pass / fail judgment on the display unit (4).