JPH0439147A - Safety securing method for automatic air filling into tire - Google Patents

Abstract

PURPOSE:To secure safety reliability with an invariably monitored fail-safe system by keeping the (a) contact relay of a noise-insensitive timer in the closed state with valve opened state maintaining signals periodically outputted from a central processor, and holding a valve open drive signal outputted to a charging solenoid valve. CONSTITUTION:A noise-insensitive timer 43 with the (a) contact relay 46 not affected by noise such as a spark is prevented from being automatically returned to the contact open side after a fixed period elapses by valve opened state maintaining signals periodically outputted from a central processor 24 confirming all safety check items, and a valve open drive signal outputted to a normally- closed charging solenoid valve 12 is maintained. If an abnormality occurs on at least one of safety check items, the valve opened state maintaining signals are not outputted correctly from the central processor 24, the noise-insensitive timer 43 is automatically returned to the contact open side, the valve open drive signal to the charging solenoid valve 12 is cut off, and it is returned to the normally-closed position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a method for ensuring safety when automatically filling tires of automobiles, aircraft, etc. with air.

(Prior art) As shown in Japanese Patent Publication No. 1-9976, the tire pressure is measured by a pneumatic sensor through a hose connected to the tire, and the difference between the set tire pressure and the measured tire pressure is used to detect the tire pressure. Determine the filling time or air release time (air release time) from the tire, electronically control the solenoid valve connected to the hose, and fill the tire with air or release air from the tire through the hose. There is an air automatic filling method.

This type of automatic air filling method uses a central processing unit (hereinafter referred to as CP).
It is essential for safety that the electronic control device, which is made up of U) and peripheral equipment (air pressure sensors, etc.), is not malfunctioning, and that a large amount of charging time may be erroneously commanded. There is a risk of the tire bursting.

In this way, equipment that can be life-threatening if it malfunctions,
Adequate failsafe systems are essential as well as traffic lights.

(Problem to be solved by the invention) Today, the reliability of CPUs has improved, but in terms of final reliability, the semiconductor system including the CPU and pneumatic sensor can be destroyed in an instant by a lightning strike or strong radiation. Considering this, there is no point in trying to increase the reliability by multiplexing the CPU and the air pressure sensor, and it will only increase the cost.

The present invention has been made in view of the above points, and is a system for automatically filling air into tires using an electronic control device composed of a microcomputer central processing unit and peripheral devices, which are susceptible to noise such as sparks. The object of the present invention is to provide a safety ensuring method that can ensure safety and reliability in the event that the central processing unit or the like is destroyed by a fail-safe system that is constantly monitored.

[Structure of the invention]

(Means for Solving the Problems) The invention of claim 1 controls the charging solenoid valve 12 and the discharge solenoid valve 14 by an electronic control device constituted by a central processing unit 24 of a microcomputer and peripheral devices. The automatic tire air control system controls the filling time of the tire 18 by the filling solenoid valve 12 and the time of air release from the tire 18 by the releasing solenoid valve 14, and controls the tire pressure to converge to the set tire pressure. In the filling method, the noise-insensitive timer 43.55.56, which has the A contact relay 46.63.66, which is not affected by noise such as sparks, automatically returns to the contact DFI side after a certain period of time has passed. The central processing unit 24, which has confirmed all the safety check items such as normality of operation, normality of timekeeping, and non-runaway of the software, is periodically outputted from the central processing unit 24, and the central processing unit 24 Noise insensitive timer 43°55,
The valve opening drive signal output to the normally closed charging electromagnetic valve 12 via the a contacts 46M, 63s, and 6f+s of 56 is maintained, and when an abnormality occurs in at least one of the safety check items, the central processing Taking advantage of the fact that the valve open state maintenance signal is not normally output from the device 24,
The noise insensitive timers 43, 55, and 56 are automatically returned to the open contact side, and the noise insensitive timers 43, 55, and 56 cut off the valve opening drive signal from the central processing unit 24 to the charging electromagnetic valve 12, and this charging is stopped. This is a method for ensuring safety during automatic tire inflation by returning the air solenoid valve 12 to the normally closed position.

The invention of claim 2 is based on the confirmation results of safety check items such as normality of filling, normality of timekeeping, and non-runaway of software, and is based on the verification result that damage to the output boat of the central processing unit 24 is unlikely to occur. At the output turn, the central processing unit 24
This is a method for ensuring safety during automatic tire air filling in which a valve open state maintenance signal is periodically output from a large number of output boats PCI to PC6 to prevent the noise insensitive timer 43 from automatically returning to the contact open side.

The invention of claim 3 provides eight contacts 631.66 of a plurality of noise insensitive timers 55.56 connected in series! This is a method of ensuring safety during automatic tire inflation in which the contacts are kept closed by a plurality of valve open state maintenance signals that are periodically output from the central processing unit 1!24 that has confirmed all safety check items.

(Function) The invention of claim 1 provides that when an abnormality occurs in at least one of the safety check items during the filling of the tire 18, which is controlled to converge to a set pressure by setting the filling and releasing times, the central processing The normal valve open state maintenance signal is no longer output from the device 24, and the noise-insensitive and reliable simple noise-insensitive timers 43, 55, and 56 fall to the fail-safe side, and the valve opening drive for the charging solenoid valve 12 is disabled. The signal goes out and charging is stopped.

In the invention of claim 2, when an abnormality occurs in at least one of the safety check items, the output turns from the plurality of output ports PcI-PC6 of the central processing unit 24 are disrupted.
Since the periodic valve open state maintenance signal cannot be obtained and the noise insensitive timer 43 automatically returns to the contact open side, the charging solenoid valve 1
The valve opening drive signal for 2 disappears and charging is stopped.

According to the third aspect of the invention, when an abnormality occurs in at least one of the safety check items, an abnormality occurs in at least one valve open state maintenance signal output from the central processing unit 24, and the corresponding noise insensitive timer 55 or 56 is activated. A contact 63! Alternatively, at least one of the valves 661 becomes open, the valve opening drive signal for the charging electromagnetic valve 12 disappears, and charging is stopped.

(Examples) Hereinafter, the present invention will be described in detail with reference to examples shown in the drawings.

First, an automatic tire air filling device, which is a premise of the safety ensuring method of the present invention, will be explained with reference to FIGS. 8 to 13.

As shown in FIG. 8, the compressor 11 has a normally closed charging solenoid valve (hereinafter referred to as the charging valve) 12.
It is communicatively connected to the hose reel 13 via. This air supply system includes a normally open solenoid valve for air release (hereinafter referred to as
A vent valve (referred to as a vent valve) 14 and a pneumatic sensor 15 are also provided. Since the air release valve 14 is normally open for safety reasons, it is kept closed by coil excitation except during air release operation.

A connector 17 is provided at the tip of the hose 16 pulled out from the hose reel 13, and this connector 17 connects to the tire 1.
It is connected to the air supply port 19 of No.8. This air supply port 19 is provided with a check valve 20 . The air pressure sensor 15 is
The tire internal pressure is measured via the hose reel 13, hose 16, connector 17, and tire-side check valve 20.

When the tire side check valve 20 is connected to the connector 17, the rod 22 of the check valve 21 built in the connector 17 is connected to the tire side check valve 20.
is pushed open against the compression coil spring 23. The check valve 21 of the connector 17 is also opened by the reaction force from the check valve 20 of the air supply port 19, but when the pressure on the check valve 20 is released, it is closed by the hose internal pressure.

Figure 9 shows the solenoid of the filling valve 12! 2! A block diagram of a control system for controlling energization of the solenoid 141 of the air release valve 14 by a microcomputer is shown. A read-only memory (ROM) for the central processing unit (hereinafter referred to as CPU) 24 of this microcomputer includes calculation formulas or restore tables for charging and releasing air.

For example, when creating a restoration table for filling, in a filling experiment conducted on the tire 18 through the check valve 20, 21, as shown in FIG. 10, the tire capacity,
Since the charging characteristic expressed by the relationship between the charging source pressure Pl+ and the charging gradient K is obtained, this relationship is made into a charging restore table and mapped to the ROM of the microcomputer.

Then, from this charging restore table, the set tire pressure (target data) T is determined as shown in Fig. 11.
By dividing the difference between GD and the measured tire pressure (tire data) TRD by the filling gradient K, an approximate value of the filling time T can be obtained.

Similarly, when creating a restore table for air release, in an air release experiment conducted from the tire 18 through the check valve 20.2+, as shown in FIG. 12, the tire capacity,
Since the air release characteristic expressed by the relationship between the measured tire pressure TRD and the air release gradient K is obtained, this relationship is made into an air release restore table and mapped in the ROM of the microcomputer. From this air release restore table, as shown in FIG. 13, the air release time T is estimated by dividing the difference between the measured tire pressure TRD and the set tire pressure TGD by the air release gradient Ka. can be found.

Next, the operation of the automatic tire air filling device shown in FIGS. 8 to 13 will be briefly explained. All calculation processing is done by CPU
24.

As shown in FIG. 10, the filling gradient K is determined from the tire capacity and the original pressure pH from the compressor 11. Further, the set tire pressure TGD is set using a key switch or the like, and the measured tire pressure TlID is obtained by the air pressure sensor 15 through the hose 16. Furthermore, the set tire pressure TGD
The differential pressure ΔP between the measured tire indenter 11D and the measured tire indenter 11D is determined. next,
As shown in FIG. 11, the filling time T is determined from this differential pressure ΔP, the filling gradient, and the like. Then, the filling valve 12 is opened and closed for this filling time T.

When the differential pressure ΔP is not positive, the measured tire pressure TRD is higher than the set tire pressure TGD, so in order to release air, first, air is released from the tire capacity and the measured tire indenter RD as explained in FIG. Find the gradient Kll. Next, as shown in FIG. 13, the absolute value of the differential pressure ΔP and the air discharge gradient K,
Find the air release time T from . And this air release time T
, the air release valve 14 is opened and closed.

In both the charging mode and the air release mode, the differential pressure Δ between the measured tire pressure TRD after air charging and air release and the set tire pressure TGD
The charging or releasing of air is repeated until the absolute value of P becomes smaller than the allowable error, and finally, when the absolute value of the differential pressure Δ■) becomes smaller than the allowable error, the charging and releasing operations are completed.

Next, a first embodiment of the safety ensuring method of the present invention will be described based on FIGS. 1 to 4. This embodiment shows the case where multiple output ports of the CPU can be utilized for this security.

As shown in FIG. 1, a variable resistor 31 for ensuring reliability of the air pressure sensor 15 is connected to an AD converter 32 of the CPU 24. The source pressure Pl+ of the compressor 11 is set in the variable resistor 31 by manual dial operation or by a simple pressure/displacement converter (pneumatic cylinder) 33 operated by the source pressure Pl+ from the compressor 11. Then, the measured value of the source pressure taken into the CPU 24 from the air pressure sensor 15 via the A-D converter 34 is compared with the source pressure set value of the variable resistor 31 to check for abnormality, deterioration, etc. of the sensor 15. do. Note that the source pressure pH may be set using a hard wire instead of the variable resistor 31.

Numerous outputs related to ensuring the safety of the CPU 24) Pct
- The PC 6 is a fail-safe CMOS (co
mplementIB me 1-oxidessai
eaadIIclor) is connected to the AND gate 42 of the eaadIIclor. The output part of this AND gate 42 is connected to a noise insensitive timer 43.

This noise insensitive timer 43 is composed of a resistor 44, a capacitor 45, and an a contact relay 46.

None of these components are susceptible to noise such as sparks and radiation.

The output port PB for the filling valve 12 of the CPU 24 is connected to the solenoid 12 of the filling valve 12 via the a contact 461 of the a contact relay 46 and the amplifier (power relay) 47.
Connected to 1.

Next, safety check items that are constantly checked in the main routine of the CPU 24 (a) (b) (c) (d) (e)
Explain. These confirm the normality of charging, the normality of timing, and the absence of runaway software.

(b) Figure 3 (a) Confirmation of normality of filling Figure 3 (a)
If the system is working normally, the charging time (counted by the interrupt timer in the CPU) should decrease each time charging is performed, so the first charging time is 11, and the second charging time is 11.
It is confirmed that the relationship 11>+2>13 holds between the first filling time 12 and the third filling time 13. When this relationship breaks down, it is considered that there is an abnormality.

(b) Figure 3 (b) Time measurement normality confirmation Figure 3 (b)
is executed by the interrupt timer on the software in the CPU.
It is sufficient to count a safety time 10, which is about 10 to 20% overtime from the expected filling time, and confirm that air filling is completed within this safe time 10. Safety time 1
If air filling is not completed within 0, it is assumed that there is an abnormality.

(c) Figure 4 Time measurement normality confirmation Figure 4 (a) shows a certain source pressure pH set in the CPU.
It is a diagram showing the relationship between filling time and tire pressure in
It suffices if the relationship is within a certain safety judgment range that differs depending on the light car, medium-sized car, and large car, but when the CPU determines that the time has reached the limit judgment range, the 4th
As shown in Figure (b), the tire pressure is checked at regular intervals before being inflated.

This FIG. 4(b) shows a method of predicting tire pressure at high speed from the change in gauge pressure of the air pressure sensor 15 that occurs at the moment when the filling valve 12 is closed. Since there is resistance from the check valves 20 and 21 between the sensor 15 and the tire 18, even after the filling valve 12 is closed during air filling,
It takes time for the internal pressure remaining in the hose 16 to stabilize within the tire 18, so when the filling valve 12 is closed, the air pressure sensor! 5, in order to immediately read the internal pressure of the tire 18, the check valve 20.21 of the tire 18 is assumed to be a resistance R, and the internal volume of the hose 16 is assumed to be a capacity C.
At the initial stage of the transition of air movement from the hose 16 to the tire 18, the combination of the check valve 20, 21 and the hose 16 is regarded as a primary lag system, and the constant time constant (RC) is used to stabilize the system. The tire internal pressure is estimated at the initial stage of the transition of the hose internal pressure change. Specifically, as explained in detail in the specification and drawings of Japanese Patent Application No. 1-249499, the first-order differential value (gradient) near the start of air movement from the hose 16 to the tire 18 is determined; The ultimately stable hose internal pressure (=tire internal pressure) is predicted by the product of this first-order differential value (gradient) and time constant (RC).

It is confirmed that the predicted tire pressure does not reach the set value or its vicinity, and when it does, the system itself is not abnormal, but it is determined that there is an abnormality from a safety standpoint.

(d) Watchdog timer (confirming that the software does not run out of control) The above safety check items include the above air pressure sensor 1.
In addition to checking based on the information obtained from step 5, for example, a watchdog timer within the software may be used to check for runaway within the software.

(e) Air pressure sensor (confirming the normality of the sensor) Air pressure sensor 1
5 is deteriorated or damaged, the source pressure measurement value is taken into the CPU 24 from the air pressure sensor 15 via the A-D converter 34, and the source pressure measurement value is taken into the CPU 24 from the variable resistor 31 via the A-D converter 32. Since the error with the input source pressure setting value exceeds the allowable range, the sensor 15 is abnormal.
Deterioration etc. can be confirmed.

Next, the operation of the embodiment shown in FIG. 1 will be explained with reference to FIG. 2.

As for the software in the CPU interrupt timer that is counting the charging time, the above safety check items (a), (b), (c),
Check d)(e), etc., and if all are normal,
The software of the CPU 24 sends an output port valve open state maintenance signal (101010), which has an extremely low probability of occurring when the CPU is damaged by lightning, from a large number of output boats Pct to PC6 related to ensuring the safety of the CPU 24 at regular intervals. Make it output. Since there is an inverter 41 as shown in Fig. 1, 111111 is input to the AND gate 42 at fixed time intervals, and as shown in Fig. 2(a).
A regular rectangular wave as shown in is outputted from this AND gate 42 to a noise-insensitive timer 43.

The relay 46 of the noise-insensitive timer 43 is excited by one rectangular wave from the AND gate 42 for a certain period of time determined by the resistance value of the resistor 44 and the capacitance of the capacitor 45, and after the certain period of time has elapsed, the a contact 46! The contact automatically returns to the open side, but the above safety check item (a) (
B) (C) (D) (E) etc. are all normal, the second
Since a regular rectangular wave is continuously output from the AND gate 42 as shown in FIG. 2(a), the relay 46 of the noise insensitive timer 43 is continuously energized as shown in FIG. 2(b). The a contact 46& is held closed.

In this way, the valve open state maintenance signal (( Out cover turn 101010)
By blocking the output port PB of the CPU 24 with the a contact 461 of the noise insensitive timer 43 and the amplifier (
The valve opening drive signal output to the solenoid 12M of the normally closed charging electromagnetic valve 12 via the power relay) 47 is maintained.

The CPU was destroyed by a lightning strike, etc., and the electronic control system went awry, causing the above safety check items (a), (b), (c), (d) (
When even one of the above (e) etc. is abnormal, the probability that the valve open state maintenance signal 101010 is outputted from the output ports Pct to PC6 is extremely low. Therefore, in this abnormal situation, there is a very high probability that this valve open state maintenance signal will not be output normally, and therefore the waveform shown in FIG. 2(a) will not be obtained, and the capacitor 45 will not be charged. , the noise-insensitive timer 43 automatically returns the a contact 461 of the relay 46 to the contact open side after counting for a short period of time, and the CP
The valve opening drive signal from the output port PR of U24 to the solenoid 12r of the charging electromagnetic valve 12 is cut off. This results in
The filling electromagnetic valve 12 automatically returns to the normally closed position, stops filling the tire 18, and prevents a tire bursting accident due to runaway filling.

Output ports PC1 to ensure the safety of the CPU 24
The larger the number of PCs 6, the more accurately the state of destruction of the CPU can be grasped, but using the large number of output ports of the CPU 24 for such safety measures is not desirable in terms of effective use of the CPU 24.

Therefore, the inverter 41 and the AND gate 42
The functions may be processed on the software of the microcomputer, or may be implemented as safety ensuring means as shown in FIGS. 5 to 7.

Next, referring to FIGS. 5 to 7, the CPU 24
We will explain how to ensure safety by using fewer boats.

4 boats of CPU24: Sl, Ill, S2.
The set port S1 and reset port Ill of the flip-flop 5I and the set port S2 and reset port R2 of the flip-flop 52 are connected to R2, respectively. Furthermore, the output port A of the flip-flop 51
and output port B of flip-flop 52 is connected to AND gate 53, inverter port A l n v of flip-flop 51 and inverter port B of flip-flop 52. , are connected to the AND gate 54. The output part of the AND gate 53 is a noise insensitive timer 5.
5, and the output of the AND gate 54 is connected to a noise insensitive timer 56.

One noise insensitive timer 55 is connected to a resistor 61. It is composed of a capacitor 62 and an a contact relay 63. The other noise-insensitive timer 56 includes a resistor 64, a capacitor 65, and an a contact relay 66. None of these components are susceptible to noise such as sparks and radiation. A relay 63 provided to the two noise insensitive timers 55 and 56. 66 a
Contacts 631 and 66t are connected in series.

The output port PR for the filling valve 12 of the CPU 24 is connected to the two noise-insensitive timers 55 and 56 connected in series.
A contact 63! , 66! and the solenoid 12 of the filling valve 12 via the amplifier (power relay) 47!
connected to.

The flip-flop 51. 52 and AND gate 53. 54 is CMO3 (
coIlplemenNr7 mehl-oxide-
seIliconduclo+) and TTL (1
+5nsislor-1daynsmouth1or-logic
), but as shown in FIG. 6, this flip-flop 51. 52 and AND gate 53. -5
Function 4 can also be processed on the CPU software, so if you do so, the output port related to ensuring the safety of the CPU 24 can be moved from port 4 in Figure 5 to port 2 in Figure 6.
Can be reduced to a boat.

Next, the operation of the embodiment shown in FIG. 5 or 6 will be explained with reference to FIG. 7.

If all of the above safety check items (a), (b), (c), (d), and (e) are normal, the CPU software sends a valve open state maintenance signal to the CPU 24's Sl,
The set signal S1 and the reset signal R1 are periodically output from the R+ port alternately, and the S2. Since the set signal S2 and the reset signal R2 are output periodically from the R2 port with different phases,
As shown in FIG. 7(a), the flip-flop 51
A rectangular signal (0°1) with waveform B is output from the flip-flop 52, and a rectangular signal (0,1) with waveform B is output from flip-flop 52.
) is output.

The AND gate 53 determines that these A waveforms and B waveforms are (
1, 1), outputs Z=1.

Further, the AND gate 54 is configured such that the A waveform and the B waveform are (0
, 0), only when its inverted signal (A, , , .

Receives B, , )= (1, 1) and outputs Y=1. The Z waveform and Y waveform are shown in FIG. 7(b).

The relays 63, 66 of the noise-insensitive timers 55, 56 change the resistance value of the resistor 61, 64 and the capacitor 6 by one square wave from the AND gate 53, 54, respectively.
It is energized for a certain period of time determined by the eight factors in 2.65, and after that certain period of time, the A contacts 63> and 661 automatically return to the contact open side, but the safety confirmation check items (a), (b), and (c) above are met. As long as (d), (e), etc. are all normal,
Regular rectangular waves Z and Y as shown in Figure 7(b)
However, from the AND gate 53°54, the noise insensitive timer 55
．． 56, the Z relay 63 of the noise insensitive timer 55 and the Y relay 6G of the noise insensitive timer 56 are continuously energized as shown in FIG. After passing through IW, Z relay 63 and Y relay 66 a contacts 63g and 66g
are both held closed.

In this way, all the safety check items (a), (b), (c), (d), (e), etc. are confirmed for the a contacts 631 and 66 of the two noise-insensitive timers 55 and 56 connected in series. A plurality of valve open state maintenance signals 31. which are periodically output from the CPU 24. R1, S2. R2 (in the case of Figure 5)
Alternatively, by keeping the contact closed using the valve open state maintenance signals z and y (in the case of Fig. 6), normally closed charging is performed from the output port PB of the CPU 24 via the a contact 631° 661 and the amplifier (power relay) 47. Solenoid 12 of solenoid valve 12 for! The valve open drive signal output to the valve is maintained.

On the other hand, if an abnormality in inflation, an abnormality in timing, or a software runaway occurs, the software built into the CPU disrupts the rhythm of at least one of the A waveform and B waveform shown in FIG. 7(a). It will be done. For example, CPU
When the set signal is no longer output from the S1 port of 24 and the A waveform remains at 0, the Y waveform from the AND gate 54 can be obtained, but the Z waveform from the AND gate 53 cannot be obtained, and the Z relay 63 A contact is ti3M
Since the valve automatically returns to the open state, the valve opening drive signal for the filling valve 12 disappears, charging is stopped, and the risk of runaway filling due to CPU damage or the like can be avoided.

Note that the a-contact relay 46.63.66 of the noise-insensitive timer 43.55.56 includes a photovoltaic diode and a MOS FET (nel!l-oxide-sem
iconduclotlield-tllccl-1+
tnsislo+)
Highly reliable semiconductor relays such as ETIJ relays (manufactured by NEC Corporation) are also included. The optical MO3FET relay can block noise between a light emitting diode and a photovoltaic diode employed in its input section.

In addition, in the embodiment, a charging solenoid valve 12 and an air discharge solenoid valve 14 are provided.
Although the present invention is not limited to this, the filling valve 12 and the release valve 14 are configured separately by a three-position switching valve.
may be configured integrally.

〔Effect of the invention〕

According to the invention of claim 1, the a-contact relay of the noise-insensitive timer, which is not affected by noise, is closed by the valve open state maintenance signal periodically output from the central processing unit that has confirmed all the safety check items. The valve opening drive signal output from the central processing unit to the normally closed charging solenoid valve is maintained in order to achieve failsafe, so the central processing unit and pneumatic pressure, which are susceptible to noise such as sparks, When air is automatically filled into tires using sensors, etc., safety and reliability in the event that the central processing unit, etc. is destroyed can be ensured by a fail-safe system that is constantly monitored and configured by the noise-insensitive timer, etc. . Also, this method
There is also the advantage that it can be realized at low cost using inexpensive relays and the like.

According to the invention of claim 2, from a large number of output ports of a central processing unit for which all safety check items have been confirmed, the valve open state maintenance signal of the output ports, which is unlikely to occur due to breakage of the output ports, is periodically transmitted. Since the noise insensitive timer is prevented from automatically returning to the contact open side, the more output ports used to ensure safety, the more
This also has the effect of increasing reliability.

According to the invention of claim 3, the plurality of noise insensitive timers connected in series are activated by the plurality of valve open state maintenance signals periodically output from the output port of the central processing unit that has confirmed all the safety check items. Since the a-contact is kept in the closed state, a highly reliable method of ensuring safety can be obtained using fewer output ports.

[Brief explanation of drawings]

Figure 1 is a circuit diagram showing an embodiment of the method for ensuring safety during automatic tire inflation according to the present invention, Figure 2 is a diagram showing its electrical signal waveform, and Figures 3 (a) and (b) are safety checks. Examples of matters (
A charging characteristic graph explaining (b), Figure 4 (a) (
b) is a charging characteristic graph explaining the safety check item example (c), FIG. 5 is a circuit diagram showing another embodiment of the present invention, and FIG. 6 is a circuit showing a modification of the embodiment in FIG. 7 is an electric signal waveform diagram for explaining the operation of the embodiment shown in FIG. 5 or the embodiment shown in FIG. 6, and FIG. A cross-sectional view of the hose connection part, Figure 9 is a system diagram of the microcomputer control system, Figure 10 is a graph for determining the filling gradient, Figure 11 is a graph for determining the filling time, and Figure 12 is the air release. The graph for determining the gradient and FIG. 13 are the graphs for determining the air release time. 12. Solenoid valve for charging, 14. Solenoid valve for releasing air, 18.
・Tire, 24・・Central processing unit, 43.55.56・
Noise insensitive timer, 46.63.66...Rele 461
, 633 , 661 ・A contact. -3! ”≧u

Claims (3)

[Claims] (1) An electronic control device composed of a microcomputer's central processing unit and peripheral devices controls the charging solenoid valve and the air release solenoid valve to determine the time and amount of time for the tire to be filled by the charging solenoid valve. In an automatic tire air filling method that controls the air release time from the tire using an air release solenoid valve and controls the tire pressure to converge to the set tire pressure, a noise-insensitive timer with an A contact relay that is not affected by noise is used. The automatic return to the open side of the contact after a certain period of time is prevented by a valve open state maintenance signal that is periodically output from the central processing unit that has confirmed all safety check items, and the central processing unit sets a noise-insensitive timer. maintains the valve open drive signal output to the normally closed charging solenoid valve via the a contact of the Taking advantage of the fact that the signal is not output normally, the noise-insensitive timer automatically returns to the contact open side, and this noise-insensitive timer cuts off the valve opening drive signal from the central processing unit to the charging solenoid valve. A method for ensuring safety during automatic tire inflation, characterized by returning an air solenoid valve to a normally closed position. (2) From the numerous output ports of the central processing unit for which all safety check items have been confirmed, valve open state maintenance signals are periodically output with an output pattern that is unlikely to occur in the event of damage to the output ports, and 2. The method for ensuring safety during automatic tire air filling according to claim 1, characterized in that the dead timer is prevented from automatically returning to the contact open side. (3) The a-contacts of the multiple noise-insensitive timers connected in series are kept in the closed state by multiple valve-open state maintenance signals that are periodically output from the central processing unit that has confirmed all safety check items. The method for ensuring safety during automatic tire air filling according to claim 1.