JPH0329604B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a tire puncture detection device for detecting a tire puncture of a vehicle running on a track using pneumatic tires.

(Prior art) Conventionally, for example, as disclosed in Japanese Patent Publication No. 58-51483, the load on a tire is detected by a load detector installed on the track, and the load signal is received and the waveform of a normal tire is detected. A known device is designed to determine whether the waveform is caused by a flat tire or a flat tire. In this device, the electrical system of the load detector using a load cell installed on the ground, for example, the signal itself may become distorted due to aging changes in resistance values, deformation or wear of the mechanism, changes in frictional resistance, etc. Become. Therefore, a load detector that is installed and used for a long period of time must be equipped with a device to correct the zero point, and from the viewpoint of ease of maintenance, the number of extra detection means such as sensors should be minimized. It is preferable to do so. (Object of the Invention) The present invention was made to solve such conventional problems, and includes a tire puncture detection device equipped with a zero point correction device and a separate sensor for zero point correction. without providing
The present invention provides a tire puncture detection device capable of performing zero point correction using a tire puncture detection signal.

(Structure of the Invention) The first gist of the present invention is to provide a load detector that detects the load from the coaxial left and right pneumatic tires using a pair of left and right pressure receivers installed on a track, and a signal from the load detector. a determination display means for processing and determining and displaying a tire puncture; a counter for counting the number of passing axles by counting the signal from the load detector; and a detection means for detecting that the train has finished passing; The automatic zero point correction circuit is configured to perform zero point correction of the load detector based on a signal from the detection means indicating completion of passage of the vehicle.

A second gist of the present invention is that the above configuration further includes a control device, and when a load detection signal is received during execution of zero point correction, the zero point correction processing is stopped, and the load detection signal and the next one are The control device is configured to perform zero point correction after a predetermined period of time after input of the load detection signal.

The above predetermined time is the first load detection signal and the second load detection signal.
What is necessary is to measure the time between the load detection signal and set the time to the time obtained by multiplying that time by a predetermined coefficient.

In the above configuration, it is detected that the train has finished passing, and the zero point correction process is executed based on the detection signal. In addition, in the second invention, if the next train approaches while the zero point correction process is being executed, the puncture is not detected for the first axle and at least the second axis, and the zero point correction process is performed after the next train has passed. I try to do it.

(Example) First, the configuration of the tire puncture detection section will be explained. In FIG. 2, 1 is a left side load detector that detects the load from, for example, the left tire among the left and right pneumatic tires on the same axis, and 2 is a right side load sensor that detects the load from the right tire. Sensor 2 may be any sensor as long as it can extract load signals in time series, and usually a load cell, pressure-sensitive switch, piezoelectric element, etc. is used, and this is installed on the tire rolling surface of the vehicle track. Both detectors 1,
2, if the internal pressure of both tires is normal, the third
As shown in Figures A and B, substantially similar waveform signals A and B are output with no significant difference in tire ground contact lengths t ₁ , t ₂ and load peak values p ₁ , p ₂ . On the other hand, in the case of an abnormal (flat) tire, a large change occurs in the detection signal on the abnormal tire side. FIGS. 3C, D, and E show the case where a change occurs in the output signal of the right side detector 2 due to a puncture of the right side tire. C is the load detector 2 where the auxiliary wheel built into the tire or coaxially attached is still present, such as when the tire first got punctured.
The output signal _B1 is shown when the tire internal pressure is maintained at a level that does not cause contact with the tire. Output signal B ₁ at this time is a normal signal (output signal of left side detector 1)
Compared to A, the tire contact length t ₂ is larger and the load peak value p ₂ is smaller. In addition, in D, the internal pressure decreases further and the auxiliary wheel hits the load detector 2,
As a result, the load peak value is reduced in the middle of the tire passage.
p ₂ is protruding, showing an output signal B ₂ that is approximately equivalent to the normal peak value p ₁ , and E is an output signal in which the load transmission by the auxiliary wheel has further increased and the protrusion amount of the load peak value p ₂ has increased. Showing B ₃ .

The output signals from both detectors 1 and 2 are as follows:
The waveform synthesizer 3 shown in FIG. 2 synthesizes the signals in a subtractive manner. The synthesized waveform by synthesizer 3 is
4. Corresponding to FIG. Figure 3 A, B
In the normal tire range, as shown in Fig. 4A and B, the tire contact lengths t ₁ and t ₂ and the load peak values p ₁ and p ₂ of the left tire side signal A and the right tire side signal B are slightly different from each other. Due to the difference, in the case of the examples shown in FIGS. 3A and 3B, signals C and D are taken out almost only on the negative side.
In contrast, the right tire was punctured in Figure 3 C, D,
In the abnormal region of E, waveform signals E, F, and G spanning both positive and negative sides are extracted as shown in FIG. 4, C, D, and E.

The output signals C to G from the waveform synthesizer 3 are input to the positive and negative level comparators 4 and 5 shown in FIG. +L, -L), and if the composite waveform signal exceeds this reference value +L, -L,
As shown in FIG. 5, a pulse signal corresponding to the exceeded portion (number of times) is output. That is, the fourth
In the case of composite waveform signals C and D in figures A and B, two negative side pulse signals C ₁ , C ₂ and
D ₁ and D ₂ are output. In the case of composite waveform signal E in FIG. 4C, which is a puncture signal, the positive side 1
, two on the negative side, a total of three pulse signals E ₁ , E ₂ , E ₃ ,
In the case of composite waveform signal F in FIG. 4D, positive and negative 2
In the case of a composite waveform signal G of four pulse signals F ₁ to F ₄ and E, a total of five pulse signals G ₁ to _{G 5} , two on the positive side and three on the negative side, are output.

As mentioned above, when a tire is punctured, a total of three or more pulse signals are output from the positive and negative level comparators 4 and 5. This pulse signal is transmitted to the logic section 14.
is sent to counters 6 and 7 through counters 6 and 7.
The total number of pulses counted in step 7 and then passed through the adder circuit 23 and counted by the judge 8 as described above (the number of times the composite waveform exceeds the positive and negative reference values +L, -L) and the preset reference pulse number. (2 pulses), and if the number of pulses exceeds this reference value (3 or more), it is determined to be abnormal (punk), and while the reset signal Rs described later is being input, the above abnormal signal is The information is input from the determiner 8 to a display unit 9 equipped with an indicator light and the like. In addition, in the determiner 8,
It is determined that there is an abnormality on the condition that pulses are output from both counters 6 and 7, and when pulses are output from only one [such as the case of Fig. 5 A and B]
, even if the number of pulses is large, it is not determined to be abnormal.

Furthermore, when the signals sent from the load detectors 1 and 2 in Fig. 2 to the trigger circuits 11 and 12 exceed a predetermined trigger level _L1 , pulse signals a and b shown in Fig. 6 A and B are output. be done. This level (first
level) L ₁ to improve detection accuracy.
It is set to a small value within a range that is not affected by errors in the zero points of the load detectors 1 and 2. These pulse signals (first signals) a and b are input to the OR circuit 13 in FIG. 2, and a reset signal R is outputted [FIG. 6C]. It is input together with output signals 4 and 5.

As shown in FIG. 7, the logic section 14 includes an OR circuit 1 which receives the output signals of the comparators 4 and 5 as one input.
5, 16, and a knot circuit 1 that inverts this signal.
7, 18, first AND circuits 19, 20 which input the output signals of the NOT circuits 17, 18 and the OR circuits 15, 16, and the AND circuit 1.
It consists of second AND circuits 21 and 22 which AND the output signals of 9 and 20 and the reset signal. Note that the output signals of the second AND circuits 21 and 22 are also input to the OR circuits 15 and 16. As a basic principle, this logic unit 14 counts the mutual behavior of the composite waveform: (a) Exceeding the positive reference value + L → exceeding the negative reference value - L (B) Exceeding the negative reference value - L → exceeding the positive reference value + L It is something to do. That is, when a signal is generated only from the comparator 4, the signal is sent to the AND circuit 19 through the OR circuit 15, and at this time, since the AND circuit 19 does not have a signal from the comparator 5, The NOR circuit 17 side is turned on and a signal is sent to the first AND circuit 21, and since the reset signal R is also sent here, a signal is sent to the counter 6. Similarly, if a signal is generated only from the comparator 5, the signal is sent to the counter 7.

The output signal of the logic section 14 shown in FIG. 2 is taken into the determiner 8 via the counters 6 and 7 and the adder circuit 23 as described above. The outputs of the counters 6 and 7 and the reset signal R are input to a comparator 24, and it is determined whether the punctured tire is on the right or left side depending on which side, positive or negative, has a larger number of input pulses.

The signal from the load detector 1 is also sent to a trigger circuit 31, and when this signal exceeds a predetermined trigger level _L2 , the signal is sent to an AND circuit 33. Similarly, the signal from the load detector 2 is also sent to the other side of the AND circuit 33 through the trigger circuit 32. This level (second level)
_L2 is set between the expected minimum value of the load peak values at the time of a puncture shown in FIG. 8 and the maximum load caused by a foreign object. above level
A signal of L ₂ or more (second signal) triggers the trigger circuit 31,
32, the AND circuit 33
A signal P is sent to the reset signal generation circuit 34 from which a reset signal Rs is sent to the comparator 24.
and is sent to the determiner 8, and only during that time the comparator 24
and causes the determiner 8 to process. The reset signal R from the OR circuit 13 is also input to the reset signal generating circuit 34.

The reset signal generating circuit 34 is constructed as shown in FIG. That is, an OR circuit 35 which receives the signal P from the AND circuit 33 shown in FIG. 2 as one input, an AND circuit 36 which receives this signal as one input, an off-delay 37 which receives this signal It has an OR circuit 38 which takes as one input, an AND circuit 39 which takes this signal as one input, and a NOT circuit 40 which takes as input the signal R from the OR circuit 13 shown in FIG. The output of the NOT circuit 40 is input to the other side of the AND circuit 39, the output of the AND circuit 39 is input to the other side of the OR circuit 38, and the output of the AND circuit 36 is input to the other side of the OR circuit 35. configured to be entered. Off-day 3 above
Reference numeral 7 is for maintaining the operation of the logic element for a certain period of time, and the hardware may be configured using a circuit element using a capacitor and a resistor, or an off-delay timer. Note that the holding time td is only required to operate the next stage logic element, and this time is usually several milliseconds to several tens of milliseconds.
It is msec.

Figure 10 shows the operation of the reset signal generation system,
By detecting the tire, L ₁ is detected as shown in Figure 10A.
A reset signal R exceeding the trigger level is generated, and then a signal P with a trigger level of level _L2 is generated as shown in FIG. 10B. As a result of the generation of signals R and P, a signal X is generated from the AND circuit 36 (FIG. 9) as shown in FIG. 10C.
As a result, the off-delay 37 is turned on, and its output side is also immediately turned on, and the signal Y is sent to the OR circuit 38 as shown in FIG. 10D. At this time,
The other input side of the AND circuit 39 has a NOT circuit 4.
Since no signal is sent by 0, no output is generated from the AND circuit 39.

When the tire passes and the reset signal R turns off, the other input side of the AND circuit 39 is turned on by the NOT circuit 40, and at this time, the output Y of one input side is also held for a certain period of time by the off-delay 37. Therefore, the AND circuit 39 is kept on for a certain period of time after the input X is turned off. Therefore, the AND circuit 39 is turned on and a reset signal Rs is output as shown in FIG. Performs signal processing. In this way, even if there is a detection signal of level L ₁ or higher, the detection process is not immediately performed, but the detection signal indicating the passing of a tire (signal exceeding level L ₂ ) is detected.
Since it is processed as a tire passing signal only when this occurs, malfunctions due to foreign objects can be reliably prevented.

Furthermore, the present invention can also be applied to tire vehicles that do not have auxiliary wheels. In this case, the third
A tire puncture is determined based on the signals of each C shown in FIGS. Further, the tire puncture detection section may adopt a configuration other than the above.

In FIG. 1, adders 41 and 42 are provided between each load detector 1 and 2 and the tire puncture detection circuit 100 and trigger circuits 11 and 12 shown in FIG.
The signals from each load detector 1 and 2 are transmitted to automatic zero point correction circuits (AZ circuits) 43 and 44, and a signal indicating that AZ processing is in progress is sent to an OR circuit 46. correction circuit 43,
The signal from 44 is also sent to adders 41 and 42, where it is combined with the signals from load detectors 1 and 2. trigger circuit 11,
The signal from 12 is sent to the AND circuit 53 through the OR circuit 51, and the display signal e during automatic zero point correction calculation from the OR circuit 46 is also sent to the AND circuit 53 through the OR circuit 52.

The automatic zero point correction circuits 43 and 44 output a bias signal to zero the load detectors 1 and 2 based on the outputs of the load detectors 1 and 2 when receiving the automatic zero point correction activation signal, and when activated. It takes some time before it is output. For this reason, the signal e is output during calculation.

The signal from the AND circuit 53 is sent to the OR circuit 54.
is sent to the AND circuit 55 and the AND circuit 58 through the reset signal Ro.
The signal is sent to the comparator 24 and adder circuit 23 in the figure.
The signal from AND circuit 53 is also sent to OR circuit 52 and OR circuit 56.

The signal from the OR circuit 51 is sent to an AND circuit 55 and a counter 61, and from the counter 61 is sent through a determiner 62 and an OR circuit 45 to the automatic zero point correction circuit 43. Although not shown, a similar signal is also sent to the automatic zero point correction circuit 44. The total number of axes Nv is input to the determiner 62,
The signal from the counter 61 is the total number of axles of each train Nv
If the value exceeds the value, the counter 61 is reset by the signal from the determiner 62, and an automatic zero point correction (AZ) start signal is outputted to the automatic zero point correction circuits 43 and 44 through the OR circuit 45. .

The signal from the OR circuit 56 is input to a timing pulse generation circuit 60, and its output is sent to the set input section of the timer 70 through a NOT circuit 71, and is also sent to the set input section of the timer 70 through an OR circuit 72.
is sent to the reset input. Further, the signal from the timing pulse generation circuit 60 is sent to the determining element 75 through the counter 81 and the determining device 82, thereby opening and closing the determining element 75. The determination unit 82 is configured to set the first axis and second axis of the passing vehicle.

The output tA from the timer 70 is sent to a comparator 73 and a multiplier 74, where it is multiplied by a time factor nAZ and sent from the holder 76 to the comparator 73 through a decision element 75. Then, the comparator 73 receives the signal from the timer 70.
tA and the signal tAZ from the retainer 76 are compared,
Only when tA is greater than tAZ, it is sent from the OR circuit 45 to the automatic zero point correction circuits 43 and 44 through the delay time element 77, and also to the AND circuit 58 through the NOT circuit 57. Furthermore, the signal from the delay time element 77 is transmitted from the OR circuit 72 to the timer 7.
0, the counter 81 and the holder 76, respectively.

FIG. 11 shows a waveform diagram when a load detection signal is generated during automatic zero point correction processing, where line 110 is the original zero point, and broken lines 101 and 102 are the first zero point of each train.
The original waveforms of the axis and the second axis, line 105, indicate the automatic zero point correction processing signal, and when the load detection signal 101 is generated during the automatic zero point correction processing, the load detection signal becomes a signal 103 that is lower by the correction amount H, and the zero point 1
07 also falls from the original zero point 110. This correction amount H is the waveform 1 of the load detection signal at the deviated zero point.
03 and the following axle signal waveform 104 are set to exceed level _L1 .

In other words, the setting is such that the number of axes can be counted even if the automatic zero point correction process starts near the peak value of the input waveform of the load signal.

If a load detection signal for the 1st axis occurs during automatic zero point correction processing, the time between the 1st axis and the 2nd axis
tA1 is counted, and automatic zero point correction processing (re-automatic zero point correction processing signal 106) is performed again after time tAZ from when the load detection signal of the second axis falls below _L1 . The zero point 107 that has gone awry due to this is the original zero point 110.
will be returned to.

That is, if the next train approaches while the automatic zero point correction process is being executed, the puncture detection process for the first axis and at least the second axis is not performed.

Note that the above tAZ is obtained by multiplying tA1 by nAZ, and this nAZ is set so that tAZ is a sufficient time for the fluctuations in the load detection signal to subside when the second axis passes. Further, it is also possible to detect that the zero point after the automatic zero point correction process has moved to the negative side beyond a certain set limit, and then perform the automatic zero point correction process again. Furthermore, after passing the first axis, the automatic zero point correction process may be performed again after a certain set time.

In FIG. 1, each axle of the train is detected by the load detectors 1 and 2, and when the axles of the train reach the total number of axles Nv as counted by the counter 61,
This is determined by the determiner 62 and outputted as a train passing completion signal to reset the counter 61. At the same time, an automatic zero point correction start signal is sent to the automatic zero point correction circuits 43 and 44 through the OR circuit 45, and the adder Load detection signals sent from 41 and 42 to the tire puncture detection circuit 100 are subjected to automatic zero point correction processing.

During this automatic zero point correction process, the processing signal e is sent to the AND circuit 53 through the OR circuits 46 and 52, but if a load detection signal exceeding level _L1 is generated during this process, the signal f is sent from the AND circuit 53.
is sent to the timing pulse generation circuit 60 through the OR circuit 56, and a reset signal Ro is sent to the addition circuit 23 and comparator 24 in FIG. 2 to stop the tire puncture detection process.

Further, the timing pulse generation circuit 60 generates a first pulse by inputting the signal f, and inputs the first pulse to the timer 70. Next, a second pulse is input to the timer 70 due to the signal exceeding the level L ₁ from the load detector, and the time value h (output tA) between these two pulses is sent to the comparator 73 and input to the multiplier 74. timekeeping factor
Multiplied by nAZ. On the other hand, the pulse from the timing pulse generation circuit 60 is input to the counter 81, and the determining element 75 is turned on in the determining device 82 only in the case of the first axis and the second axis. Therefore, the value multiplied by the multiplier 74 is transferred from the determination element 75 to the holder 7.
6 and held. Signals from the third axis onward are not sent to the holder 76 because the determining element 75 is turned off by the determining device 82.

The timer 70 starts counting a new time by inputting the second pulse from the timing pulse generation circuit 60, and this is sent to the comparator 73. Normally, the third and subsequent axes pass at similar intervals. comparator 73
There is no output from. From timer 70 to comparator 73
When the signal sent to tAZ becomes larger than tAZ, it passes from the comparator 73 to the delay time element 77 and is sent from the OR circuit 45 to the automatic zero point correction circuit 4 as an automatic zero point correction start signal.
3 and 44, and is also sent as a reset signal to the timer 70, counter 81, and holder 76 to reset them, respectively.

Next, the above operation will be explained using the flowchart shown in FIG. First, if a signal is sent from the load detector while waiting for the next train within a predetermined time after a train has passed, the signal is set to a level in step _S1 .
It is determined whether the level L ₁ has been exceeded or whether it is distortion. If the level L ₁ has been exceeded, the process returns to the beginning of the step; if it has not exceeded the level L 1, zero point correction processing is started in step S ₂ .
If a load detection signal is input during this process, it is determined in step _S3 whether the signal exceeds level _L1 , and if it has not exceeded level L1, the process proceeds to step _S4 .
It is determined whether the zero point correction processing has been completed or there is distortion. If it has not been completed, the process returns to step _S3 , and if it has been completed, the process returns to the beginning of the flow and enters the waiting state for the next train.

If the level _L1 is exceeded in step _S3 , it is determined in step _S5 whether or not the zero point correction process has been completed, and if completed, the number of passing axles (1) is counted in step _S6 . Next, in step _S7 it is determined whether the signal has fallen below level _L1 , and if it has fallen, then in step _S8 the time measurement of tA1 (passage time between axles) is started. Next, in step _S9 , it is determined whether the signal of the next axis has exceeded the level _L1 and has further decreased below the level _L1 .
Stop the time measurement of tA1 at _S10 . and step
In _S11 , the time tA1 is multiplied by the time factor nAZ to set the time tAZ until the zero point correction process.

Note that this time nAZ is set to be a sufficient time for the fluctuations in the load signal when the axle passes through to subside.

Next, in step _S12 , measurement of the elapsed time tX from the completion of the passage of the last axle is started, and step _S13 is started.
This time tX is compared with the above set time tAZ,
If tX becomes larger, the process returns to step _S2 and zero point correction processing is started.

Fig. 13 shows the flow for re-performing the zero point correction process when the load detection signal is generated during the zero point correction process, taking advantage of the fact that the load detection signal deviates to the negative side. There is.

In the figure _, the processing from step S ₁ to step S ₄ is the same as that in FIG _.
If it exceeds the level _L1 , the time measurement of tY (the time of the detection signal exceeding the level _L1 in FIG. 11 in FIG. 11) is started in step S15, and then it is determined in step _S16 whether or not the zero point correction process has been completed. If the process has not been completed, the determination at step _S14 is repeated, and if it has been completed, the process moves to step _S17 . and step
It is determined in _S17 whether the signal has fallen below level _L1 , and if it has fallen below _L1 , it is multiplied by the time factor nAZ in step _S18 to find the time tAZY until the next zero point correction process.

Next, in step _S19 , the above-mentioned tAZY and tY are compared in magnitude, and if tY is larger than tAZY, the time measurement of tY is stopped in step _S20 , and then, in step _S21 , it is determined whether the load signal is smaller than _-L1 . If it is large, the process returns to the beginning of the flow, and if it is small, the zero point correction process is started.

(Effects of the Invention) As explained above, in the tire puncture detection device of the present invention, the tire puncture detection device detects when a train has finished passing, and performs zero point correction processing based on the detection signal. In addition, since there is no need to install a detection means for zero point correction processing on the running surface, manufacturing, installation, and maintenance of the device can be easily performed.

Additionally, since the invention can be configured and installed independently of other devices in the transportation system, the device is also very easy to manufacture, install, and maintain.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of this invention.
Figure 2 is a block diagram of the tire puncture detection section.
Figure 3 is an output waveform diagram of the load detector, Figure 4 is a composite waveform diagram corresponding to its output, Figure 5 is an output waveform diagram from the positive and negative level comparators, and Figures 6 A to C are trigger circuits. 7 is a circuit configuration diagram of the logic section in FIG. 2, FIG. 8 is an explanatory diagram of high and low trigger levels, FIG. 9 is a circuit diagram of the reset signal generation circuit in FIG. 2, and FIG. 11 is an explanatory diagram showing the relationship between the load detection signal and the zero point correction processing, FIG. 12 is a flowchart of the detection processing according to the present invention, and FIG. 13 is a further It is a flowchart of a detection process showing an example. 1, 2...Load detector, 8...Judgment device, 9...
Display unit, 11, 12, 31, 32...Trigger circuit, 24...Comparator, 34...Reset signal generation circuit, 43, 44...Zero point correction processing circuit.

Claims (1)

[Claims] 1. A load detector that detects the load from the coaxial left and right pneumatic tires using a pair of left and right pressure receivers installed on the track, and a signal from the load detector that processes the signals to detect tire punctures. It has a judgment display means for judging and displaying, a counter for counting the number of passing axles by counting the signal from the load detector, a detection means for detecting that the train has finished passing, and an automatic zero point correction circuit. The tire puncture detection device is characterized in that the automatic zero point correction circuit is configured to perform zero point correction of the load detector based on a signal from the detection means indicating completion of passage of the vehicle. 2 A load detector that detects the load from the coaxial left and right pneumatic tires with a pair of left and right pressure receivers installed on the track, and a judgment display that processes the signal from this load detector to determine and display a tire puncture. means, a counter for counting the number of passing axles by counting the signal from the load detector, a detection means for detecting that the train has finished passing, an automatic zero point correction circuit, and a control device, This automatic zero point correction circuit is configured to perform zero point correction of the load detector based on a signal from the detection means indicating completion of passage of the vehicle, and if a load detection signal is received during execution of zero point correction, zero point correction is performed. A tire puncture detection device characterized in that the control device is configured to stop processing and perform zero point correction after a predetermined time after the load detection signal and the next load detection signal are input. 3. The predetermined time is set to a time obtained by measuring the time between the first load detection signal and the second load detection signal and multiplying that time by a predetermined coefficient. The tire puncture detection device according to scope 2.