JPH058619A - Tire pressure control device - Google Patents

Abstract

PURPOSE:To improve the durability of a tire pressure control device by which the tire pressure of wheels can be controlled from the car body side in a car running condition. CONSTITUTION:A pressure control device 70 mainly consisting of a compressor 10, booster valves 42 to 46, and reducing valves 60 and 62, and controlled.by a controller 72, is connected to the tire inner chambers 26 and 36 of the right side and the left side wheels, passing through rotary air seal devices 22 and 32, and manual coaks 24 and 34. Furthermore, when the boosting speed of the pressure of the pressure control device 70, when the controller 72 is used for the tire pressure control, is fast abnormally, the tire control is stopped and the pressure is made at the atmosperic pressure. On the other hand, when the reducing speed of the pressure in the tire pressure controlling condition is fast abnormally, the pressure control device 70 is converted to the boosting operation, and when the boosting speed of the pressure at that time is fast abnormally, the tire pressure control is stopped making the pressure at the atmospheric pressure. And after that in either case, when the pressure becomes to the pressure of the releasing or higher, the tire pressure control is to be restarted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire pressure control device capable of automatically controlling a tire pressure of a wheel from a vehicle body side while the vehicle is traveling, and particularly to a load applied to the tire pressure control device. It is related to the technology of improving the reliability of the device by reducing it.

[0002]

2. Description of the Related Art A tire pressure control device is generally used in Japanese Utility Model Laid-Open No. 63-63.
As described in JP-A-82606, the air inlet / outlet of the tire inner chamber, which is the air chamber in the tire of the wheel, is passed through a rotary air seal device provided at the center of the wheel to a pressure control device on the vehicle body side. It is connected to the controller and is configured to perform tire pressure control for monitoring the tire pressure with a pressure sensor and increasing or decreasing the tire pressure via a pressure control device to control the tire pressure to a target pressure. The pressure control device is usually configured to include a pressure source such as a compressor, a solenoid valve, etc., and the rotary air seal device forms an air passage between a rotating member that rotates with a wheel and a non-rotating member. Therefore, it is usually composed mainly of an air seal including a rubber lip.

[0003]

In this type of tire pressure control device, it is important to improve the reliability of, for example, the rotary air seal device in order to always ensure a normal tire pressure. However, studies by the applicant have revealed that it is difficult for the conventional tire pressure control device to sufficiently improve the reliability of the rotary air seal device. In the conventional tire pressure control device, the pressure control device and the rotary air seal device are made to communicate with the tire inner chamber regardless of whether or not it is necessary to change the tire pressure by the pressure control device. This is because, for example, the lip of the device is constantly kept in sliding contact with the surface of the rotating member under a considerably high pressure.

An object of the present invention is to improve the reliability of a rotary air seal device in a tire pressure control device.

[0005]

The gist of the present invention is to provide a tire pressure control device including the rotary air seal device, a pressure control device, a controller and a pressure sensor, wherein a rotary air seal device is installed from an air inlet / outlet port of a tire inner chamber. A manually operated on-off valve is provided on the air inlet / outlet side of the rotary air seal device in the tire outer chamber, which is an air chamber extending through the pressure control device, and the on-off valve is operated in accordance with the manual operation. And the rotary air seal device are communicated with each other, and the closed state that shuts them off from each other, and the pressure sensor is a portion of the tire outer chamber on the pressure control device side with respect to the on-off valve. The pressure reducing rate of the pressure of the pressure control device at the time of tire pressure control is detected by using the pressure sensor, and the controller is provided with If earlier than pressure reference value,
The pressure control device is operated to increase the pressure, and the pressure increase speed of the pressure control device at that time is detected using the pressure sensor.If the pressure increase speed is faster than the pressure increase reference value, the pressure control device The reason is that the pressure is atmospheric pressure.

The on-off valve is usually connected to the air inlet / outlet of the tire inner chamber. For example, it is connected to the air inlet / outlet of the rotary air seal device on the tire inner chamber side. Of these, the rotary air seal device can be connected to any position as long as it is located at one position on the air inlet / outlet side.

[0007]

The control pressure chamber to which the pressure of the pressure control device acts is an air chamber which reaches the tire inner chamber from the pressure control device through the on-off valve when the on-off valve is in the open state, whereas the on-off valve is In the closed state, the air chamber extends from the pressure control device to the on-off valve. Since the volume of the control pressure chamber in the latter case is usually much smaller than the volume of the control pressure chamber in the former case, when the pressure control device is operated to increase or decrease pressure, The pressure of the pressure control device, that is, the pressure increasing speed or the pressure decreasing speed of the pressure detected by the pressure sensor becomes faster when the on-off valve is in the closed state than when it is in the open state. However, it is conceivable that the reason why the decompression speed becomes faster is not only that the on-off valve is closed but also that the tire bursts, for example, although the on-off valve is open.

Based on such a fact, in the tire pressure control device according to the present invention, the pressure reducing rate of the pressure of the pressure control device at the time of tire pressure control is detected by using the pressure sensor, and the pressure reducing rate is the pressure reducing reference. If it is faster than the value, it is expected that the on-off valve will be in the closed state immediately, and the pressure control device will not increase the pressure by increasing the pressure of the pressure control device to atmospheric pressure by stopping the tire pressure control. The pressure increase rate of the pressure of the pressure control device at that time is detected using the pressure sensor, and it is expected that the on-off valve is closed only when the pressure increase rate is faster than the pressure increase reference value. The tire pressure control is stopped and the pressure of the pressure control device is set to atmospheric pressure. When the depressurization rate is faster than the depressurization reference value, the pressure of the pressure control device is set to the atmospheric pressure on condition that the pressure increase rate is also faster than the pressure increase reference value.

The "controller" in the present invention is, for example, a pressure increasing speed of the pressure control device during tire pressure control (different from the pressure increasing speed when the pressure reducing speed is higher than the pressure reducing reference value). If is faster than the pressure increase reference value, the pressure of the pressure control device can be immediately set to atmospheric pressure by predicting that the on-off valve is in the closed state.

[0010]

Therefore, according to the present invention, for example, the fact that the on-off valve is in the open state and the tire is bursting is prevented from being erroneously recognized as the fact that the on-off valve is in the closed state.
If the open / closed state of the on-off valve is correctly predicted and the on-off valve is closed, tire pressure control is stopped, the pressure of the pressure control device is set to atmospheric pressure, and the rotating air seal device is not put under unnecessary pressure As a result, the durability of the rotary air seal device is improved, and the reliability of the tire pressure control device is improved.

Further, according to the present invention, since the tire pressure control is stopped when the on-off valve is closed, the tire pressure control is not hunted and the pressure control device is not frequently operated in vain. The effect is also obtained. The volume of the control pressure chamber on which the pressure of the pressure control device acts is considerably smaller when the pressure control device is disconnected from the tire inner chamber than when communicating with the tire inner chamber. Therefore, if the pressure control device is operated even if the on-off valve is closed, the pressure inside the control pressure chamber changes sensitively, and pressure control may occur due to response delay of the solenoid valve, pressure sensor, etc. Hunting causes the pressure control device to frequently operate in vain.

Further, according to the present invention, even if the rotary air seal device is damaged and the sealing function is impaired, a normal tire pressure can be secured in the tire inner chamber as long as the open / close valve is in the closed state. There is also a fail-safe effect that the vehicle travel can be secured.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tire pressure control device according to an embodiment of the present invention will be described in detail below with reference to the drawings. 1 in FIG.
Reference numeral 0 is a compressor as a pressure source. An air passage 14 extends from the outlet port of the compressor 10, and two air passages 16 and 18 branch off from the end thereof. One of the air passages 16 reaches a tire inner chamber 26 of the right wheel through a pressure sensor 18, an air filter 20, a rotary air seal device 22 provided in the center of the right wheel of the vehicle, and a manual cock 24 as an opening / closing valve, and the other of the other. Similarly to the air passage 18, the pressure sensor 28, the air filter 30, and the rotary air seal device 32 provided at the center of the left wheel of the vehicle.
Further, it reaches the tire inner chamber 36 of the left wheel through the manual cock 34 as an opening / closing valve.

The manual cocks 24 and 34 are respectively connected to air inlets and outlets (not shown) of the tire inner chambers 26 and 36. Further, the manual cocks 24, 34 are operated by the driver of the vehicle so as to be closed when the tire pressure control is not necessary and opened only when the tire pressure control is necessary.

A drain tank 40 for removing water from the air discharged from the compressor 10 is provided in the air passage 14, and a pressure increasing valve 42 common to the left and right wheels is further provided. The booster valve 42 is always closed, but when the solenoid is excited, it opens to open the compressor 1
High-pressure air from 0 is supplied to the air passages 16 and 18.
Further, pressure increasing valves 44 and 46 are also provided in the air passages 16 and 18, respectively. The pressure increasing valve 44 is for the right wheel only, and the pressure increasing valve 46 is
Is dedicated to the left wheel. These pressure increase valves 44, 4
Similarly to the pressure increasing valve 42, 6 is also always closed, but when the solenoid is excited, it opens to supply high-pressure air from the pressure increasing valve 42 to the tire inner chambers 26, 36.

Each of the pressure increasing valves 42, 44 and 46 is a poppet type opening / closing valve having two ports and two positions (hereinafter, simply referred to as a poppet valve). By the way, this kind of poppet valve generally has a one-way self-sealing property. In this poppet valve, the respective pressures of its two ports act in opposite directions on the poppet as a valve element, and as a result, the pressure in one port (hereinafter referred to as the first port pressure) is the poppet. On the contrary, the pressure in the other port (hereinafter, referred to as the second port pressure) acts in the direction in which the poppet is seated on the valve seat, and in the direction in which the poppet is separated from the valve seat.
Therefore, when the first port pressure is higher than the second port pressure, the poppet is strongly pressed against the valve seat to improve the sealing performance, but when the second port pressure is higher than the first port pressure, the poppet valve spring is pushed. The force that pushes the valve against the valve seat is diminished, and the sealing performance is slightly reduced.

Since the pressure increasing valves 42 to 46 have such a one-way self-sealing property, the pressure increasing valve 42 has the first port on the compressor 10 side and the second port on the tire inner chambers 26, 36 side. While the one-way self-sealing property in the direction from the compressor 10 side toward the tire inner chambers 26, 36 side is realized, the first port of each pressure increasing valve 44, 46 has the first port of each tire inner chamber 26, 36 side, The two ports are on the side of the compressor 10, and the one-way self-sealing property in the direction from each tire inner chamber 26, 36 side toward the compressor 10 side is realized. That is, as long as all the pressure increasing valves 42 to 46 are closed, the tire inner chambers 26 and 36 side and the compressor 10 side are reliably shut off from each other. By the way, the compressor 10 functions not only as a pressure source for tire pressure control but also as a pressure source for an air brake of a vehicle. Therefore, since the pressure boosting valves 42 to 46 realize the bidirectional self-sealing property, both the securement of the tire pressure and the securement of the air brake force are surely ensured. In the figure, the broken lines with arrows attached to the pressure increasing valves 42 to 46 indicate the self-sealing direction.

Each pressure increasing valve 4 of each air passage 16, 18
Air passages 50 and 52 are connected to portions between the pressure sensors 4 and 46 and the pressure sensors 18 and 28, respectively. Each of the air passages 50 and 52 is exposed to the atmosphere via a dedicated pressure reducing valve 60 and 62 and a silencer 64 common to them.

The pressure reducing valves 60 and 62 are always closed, but they are opened when the solenoid is excited to open the respective tire inner chambers 2.
6 and 36 are opened to the atmosphere to reduce the tire pressure. The pressure reducing valves 60 and 62 are also poppet type, and as shown by broken lines with arrows in the figure, one-way self-sealing property is realized from the tire inner chambers 26 and 36 side toward the atmosphere side. ing.

As is clear from the above description, in this embodiment, the compressor 10, the air passages 14, 50,
52, the portion of the air passages 16 and 18 on the compressor 10 side from the connection point with the air passages 50 and 52, the drain tank 40, the pressure increasing valves 42 to 46, the pressure reducing valves 60 and 62, and the silencer 64, and the compressor 10 is driven. Motor 66
A pressure control device 70 is constituted by the and. Also,
For the right wheel, the tire outer chamber is constituted by the manual cock 24 and the portion of the air passage 16 that connects the connection point with the air passage 50 to the manual cock 24. For the left wheel, the manual cock 34 and the air are provided. A portion of the passage 18 that connects the connection point with the air passage 52 and the manual cock 34 constitutes an outer tire chamber.

The pressure increasing valves 42 to 46, the pressure reducing valves 60 and 62, the motor 66 and the pressure sensors 18 and 28 are connected to a controller 72 mainly composed of a computer.
A target pressure setting means 74 for setting a target pressure of the tire pressure is connected to the controller 72. The target pressure setting means 74 has a select switch that is operated by the driver of the vehicle and that switches the setting of the target pressure to three stages of high, medium, and low, and the height according to the operating state of the select switch. To the controller 72.

Computer ROM of controller 72
A tire pressure control program is stored in. The controller 72 executes the tire pressure control program to cause the pressure sensors 18 and 28 to detect the tire pressure (more precisely, the pressure control device 7 detected by the pressure sensors 18 and 28).
The pressure increasing valves 42 to 46 and the pressure reducing valves 60 and 62 are controlled so that the tire pressure becomes the target pressure while monitoring (zero pressure).

The state of the tire pressure control will be described below with reference to FIG.
The pressure increasing mode flowchart, the pressure reducing mode flowchart in FIG. 3, and the change in the operating state of each operating component in FIG. 4 will be described. Before the controller 72 is powered on, the pressure increasing valves 42 to 46 and the pressure reducing valves 60 and 62 are all closed.

First, the case where the power of the controller 72 is turned on to start the tire pressure control this time with the manual cocks 24 and 34 in the open state will be described.

In this case, the controller 72 first determines whether or not the tire pressures of the right and left wheels are within the target range defined by the target pressure ± α [kPa] by using the pressure sensors 18 and 28. ..

The value of this α is obtained immediately after the controller 72 is turned on, immediately after the setting of the target pressure by the select switch is changed, and immediately after it is determined that the manual cocks 24 and 34 are moved from the closed state to the open state ( The determination will be described later in detail) and is 10 and otherwise 30. In the above cases, the target range is set narrow according to the performance of the pressure control device 70 and the pressure sensors 18 and 28, while in other cases, the tire temperature and road surface irregularities are used to determine the tire range. The target range is set wide in consideration of variations in tire pressure due to input to the tire.

When the tire pressure is within the target range, the controller 72 maintains the tire pressure by keeping the pressure increasing valve 42 or the like as it is, and when the tire pressure is out of the target range, the controller 72 operates the pressure increasing valve 42 or the like. ..

Hereinafter, the case where it is determined that the tire pressure is lower than the target range and the case where it is determined that the tire pressure is higher than the target range will be described in order. Incidentally, since the tire pressure originally changes independently between the right wheel and the left wheel,
Although the tire pressure is not always equal between the two wheels, it is assumed for the sake of simplicity that the tire pressure changes while being kept equal between the two wheels.

First, when it is determined that the tire pressure is lower than the target range, the controller 72 shifts to the pressure increasing mode, turns on the compressor 10 and excites the pressure increasing valves 42 to 46. Switch to the open state.
As a result, high-pressure air is generated by the pressure increasing valve 42 and each pressure increasing valve 44,
The tire pressure of each wheel is increased by being supplied into the tire inner chambers 26, 36 through the order of 46. If this pressure increase is performed for a certain time (for example, 60 seconds), the controller 72
Calculates the pressure increase rate by dividing the amount of pressure increase during that period by the constant time.

The speed at which the control pressure is increased is such that the tire does not burst and the air pressure in the tire pressure control device (to be exact, the air passage between the compressor 10 and the manual cocks 24, 34) is increased. If there is no leakage (hereinafter, simply referred to as air leakage), and if the manual cocks 24 and 34 are in the open state, the speed is higher than the lower limit reference speed (0) and equal to or lower than the upper limit reference speed (positive value). When there is no leakage and the manual cocks 24 and 34 are in the closed state, the speed becomes higher than the upper limit reference speed. Also, the manual cocks 24 and 34 are in the open state and the tire is bursting, or the air leakage is In some cases, it will be less than the lower limit reference speed.

Regarding the tire pressure control this time, it is assumed that the manual cocks 24, 34 are in the open state (no air leakage or tire burst), so this time, the pressure increase rate is the upper limit reference speed and the lower limit reference speed. It is determined to correspond to the case between (and in the case of “normal” in FIG. 2).
In this case, the pressure-increasing valves 42 to 46 are kept open even after that, and the tire pressure increases. After the end of the determination, the controller 72 periodically detects the tire pressure (more accurately, an estimated tire pressure described later) by the pressure sensors 18 and 28, and the control is defined by the target pressure ± 10 [kPa]. It is periodically determined whether or not it is within the range (unlike the previous target range, its width is unchanged).

When the tire pressure enters the control range due to the pressure increase, the controller 72 controls the pressure increase valves 42 to 46.
And wait until a fixed time (for example, 1 second) elapses. It waits until the air flow between the booster valves 42 to 46 and the tire inner chambers 26, 36 becomes sufficiently quiet. If the air flow becomes quiet enough, the controller 72
The tire pressure is again detected by the pressure sensors 18 and 28 (true tire pressure is detected), and it is determined whether or not the tire pressure is within the control range. If so, it is determined that the tire pressure is truly within the control range. After making a determination, the process returns to the above-described step of determining whether or not the tire pressure is within the target range, but if it is determined that the tire pressure is insufficient for the control range, the pressure increase mode is continued and the tire pressure is When it is determined that is excessive with respect to the control range, the pressure increasing mode is switched to the pressure reducing mode described later.

The case where it is determined that the tire pressure is lower than the target range has been described above. However, when it is determined that the tire pressure is higher than the target range, the controller 72 shifts to the pressure reducing mode to reduce the pressure. The valves 60 and 62 are excited and opened to release the air in the tire inner chambers 26 and 36 to the atmosphere through the pressure reducing valves 60 and 62. Controller 7
After performing this pressure reduction for a fixed time (for example, 30 seconds), 2 calculates the pressure reduction rate in the same manner as in the case of pressure increase, and determines the magnitude relationship between the pressure reduction rate and the upper limit reference speed and the lower limit reference speed.

Since it is assumed that the manual cocks 24 and 34 are open (no air leakage or tire burst) this time, if the pressure reducing speed is between the lower limit reference speed and the upper limit reference speed this time. (In FIG. 3, the case of “normal” is determined). Then the controller 7
In No. 2, similarly to the case of the pressure increase mode, it is determined whether or not the tire pressure is within the control range. Then, if it is determined that the tire pressure is within the control range, the process returns to the determination step of whether or not the tire pressure is within the target range, but if it is determined that the tire pressure is excessive with respect to the control range, the pressure reduction mode is set. If it is determined that the tire pressure is insufficient for the control range, the pressure reducing mode is replaced with the pressure increasing mode.

Therefore, when the tire pressure control is performed in a state where the manual cocks 24 and 34 are kept open, the operating state of each operating component is changed, for example, as shown in FIG.

That is, first, since the tire pressure has dropped from the target range, the compressor 10 is turned on and the pressure increase valves 42 to 46 are opened. During this pressure increase, the estimated tire pressure (temporary tire pressure in a state where the air flow is still still) is periodically detected (the true tire pressure is estimated) by using the pressure sensors 18 and 28, and eventually, Assuming that the control range has been entered, the compressor 10 is OF
In the F state, the pressure increase valves 42 to 46 are closed, and it is waited for the air flow between the pressure control device 70 and the tire inner chambers 26, 36 to stop. When the air flow has stopped, the true tire pressure is detected (measured) using the pressure sensors 18 and 28, and since it becomes higher than the control range, the pressure reducing valves 60 and 62 are opened. .. Thereafter, similarly to the case of increasing the pressure, the tire pressure is measured and the magnitude is judged.

The case where the manual cocks 24 and 34 are in the open state has been described above, but the manual cocks 24 and 3 will be described below.
The case where 4 is in the closed state will be described.

As in the previous case, the controller 72
Determines whether the tire pressure of each of the right and left wheels (more precisely, the control pressure of the pressure control device 70) is within the target range, and it is determined that the control pressure is smaller than the target range. If it is determined that the pressure is larger than the target range, the mode is changed to the pressure increasing mode.

If the pressure increasing mode is entered, the controller 7
2 is similar to the previous case, the pressure increase speed is calculated and the pressure increase speed is judged to be large or small. This time, the manual cock 24,
Since it is assumed that 34 is in the closed state (no air leakage), this time, it is determined that the case corresponds to the case where the pressure increasing speed is faster than the upper limit reference speed (indicated by "sudden increase" in FIG. 2). Then, the controller 72 uses the manual cock 2
4, 34 are determined to be in the closed state, the pressure increase valves 42 to 46 are demagnetized to return to the closed state, the current pressure increase operation is stopped (the tire pressure control this time is stopped), and the compressor 10 is turned on. Turn off. Further, the pressure reducing valves 60, 6
2 is opened for a fixed time (for example, 1 to 2 seconds) to reduce the tire pressure to atmospheric pressure.

The tire pressure is reduced to the atmospheric pressure after it is determined that the manual cocks 24 and 34 are in the closed state, so that the rotary air seal devices 22 and 32 are prevented from being unnecessarily put under the pressure. This is to detect the fact that the manual cocks 24, 34 are opened after it is determined that the cocks 24, 34 are in the closed state.

After it is determined that the manual cocks 24, 34 are in the closed state, the control pressures are increased by the pressure increasing valves 42 to 46 to a height considerably higher than the tire pressure, and the manual cocks 24, 34 are opened in this state. It is possible, for example, to use the fact that the control pressure is reduced to the tire pressure to detect the fact that the manual cocks 24, 34 are opened. However, in this case, the rotary air seal devices 22, 32
Will always be under pressure. Therefore, in the present embodiment, when it is determined that the manual cocks 24, 34 are in the closed state, the pressure reducing valves 60, 62 are opened and the control pressure is reduced to atmospheric pressure.

On the other hand, when the pressure reducing mode is entered, the controller 72 calculates the pressure reducing rate and determines the magnitude of the pressure reducing rate in the same manner as in the previous case, but this time, the manual cocks 24 and 34 are closed. Since it is assumed that (no air leakage), this time, when the depressurization speed is faster than the upper limit reference speed (this is one aspect of the “depressurization reference value” in the present invention) (in FIG. 3, “sudden decrease”). (When represented)). However, in this case, unlike the case of the pressure increasing mode, the controller 72 does not immediately determine that the manual cocks 24 and 34 are in the closed state. Specifically, the controller 72 shifts to the aforementioned pressure increasing mode after closing the pressure reducing valves 60 and 62. The controller 72 calculates the pressure increase rate, calculates the pressure increase rate, and determines the magnitude of the pressure increase rate, and if the pressure increase rate is faster than the upper limit reference speed (this is one aspect of the “pressure increase reference value” in the present invention). Is determined that the manual cocks 24, 34 are closed and there is no air leakage, and if the pressure increase speed is less than or equal to the lower limit reference speed, the manual cocks 24, 34 are open and the tire is It is determined that there is a burst or there is an air leak.

After it is determined that the manual cocks 24 and 34 are closed and the tire pressure control this time is stopped, the controller 72 periodically detects the control pressure using the pressure sensors 18 and 28, It is periodically determined whether or not it has risen to a predetermined release pressure (for example, 50 [kPa]) or more. If it is determined that the control pressure does not rise above the release pressure, the controller 72 determines that the manual cock 2
When it is determined that the control pressure has risen above the release pressure, it is determined that the manual cocks 24 and 34 have been opened. The determination is returned to the determination step of whether or not the tire pressure is within the target range, and the tire pressure control this time is restarted from there.

After the manual cocks 24, 34 are determined to be in the closed state and the control pressure is reduced to atmospheric pressure, the control pressure is reduced by a slight air leak from the manual cocks 24, 34 or the pressure increasing valves 42-46. May rise from atmospheric pressure. In this case, when the control pressure reaches the release pressure due to the increase, the controller 72 controls the pressure control device 70 so that the control pressure falls within the control range. At this time, if the manual cocks 24 and 34 are in the closed state, it is determined that the manual cocks 24 and 34 are in the closed state due to the rapid increase in the pressure increase rate, and the control pressure is reduced to the atmospheric pressure again.

Further, this time, the controller 72, when the pressure increasing speed is equal to or lower than the lower limit reference speed (in FIG. 2,
If it is determined that “there is no pressure increase or decompression”), the manual cocks 24 and 34 are in the open state and the tire is bursting or there is air leakage, and then the tire or The driver of the vehicle is warned that there is something wrong with the tire pressure control device, the compressor 10 is turned off, and the tire pressure control is completed and the power is automatically turned off. After that, again the controller 72
The controller 72 does not restart the tire pressure control unless the power is turned on. If the decompression speed is less than or equal to the lower limit reference speed this time (in FIG. 3,
The tire pressure control is also terminated when it is determined that the case "represents" no pressure drop ") is applicable.

As is clear from the above description, in the present embodiment, the manual cocks 24, 34 are determined from the changing speed of the pressure.
If the open / closed state is determined, and if it is determined to be in the closed state, the variable pressure operation of the pressure control device 70 is stopped to prevent hunting of the pressure control. Therefore, the durability of the tire pressure control device is improved, and the reliability of the tire pressure control device is improved.

Furthermore, in this embodiment, it is not immediately determined that the manual cocks 24 and 34 are in the closed state because the pressure reducing speed is abnormally fast, and the pressure is increased instead of being reduced.
Only when the boosting speed is abnormally fast does manual cock 2
It is determined that the manual cocks 24 and 34 are in the closed state, so that the manual cocks 24 and 34 can detect the fact that the manual cocks 24 and 34 are in the open state and the tire is bursting or that there is an air leak. It is also possible to obtain the effect that it is possible to prevent the false recognition of the fact that the closed state is present.

Further, in the present embodiment, if it is determined that the manual cocks 24, 34 are closed, the pressure control device 70 is depressurized and the control pressure thereof is reduced to atmospheric pressure. The rotary air seal devices 22 and 32 do not need to be put under pressure unnecessarily, the durability thereof is improved, and the reliability of the tire pressure control device is further improved.

Further, in this embodiment, the manual cock 2
The open / closed state of 4, 34 is detected by using the pressure sensors 18, 28 that should originally detect the tire pressure, and it is not essential to add a dedicated component for the detection, so that no extra cost is required. The effect is also obtained.

Further, in this embodiment, the manual cocks 24 and 3 are operated while the tire pressure control by the controller 72 is stopped.
4 is opened, the fact is automatically detected by the controller 72, and the suspended tire pressure control is automatically restarted.
It is not indispensable to input the fact to the controller 72 every time the valves 4, 34 are opened, and the usability of the tire pressure control device is improved.

As a measure for preventing hunting in pressure control in the conventional tire pressure control device, the manual cock 2 is used.
It is conceivable to increase the volume of the air chamber between the pressure control device 70 and the pressure control device 70. By doing so, hunting is certainly reduced to some extent. However, it is inevitable that the space for mounting the tire pressure control device in the vehicle and the cost of the device will increase. On the other hand, in the present embodiment, since hunting is prevented without increasing the volume of the air chamber, it is possible to obtain an effect that the installation space of the tire pressure control device and the device cost do not increase.

In this embodiment, the target pressure for tire pressure control is set according to the driver's operation. For example, the running state of the vehicle (including the road surface state) is detected. The target pressure may be automatically set accordingly.

While one embodiment of the present invention has been described in detail with reference to the drawings, various modifications and improvements can be made based on the knowledge of those skilled in the art without departing from the scope of the claims. Of course, the present invention can be carried out in the manner in which it is applied.

[Brief description of drawings]

FIG. 1 is a system diagram of a tire pressure control device that is an embodiment of the present invention.

FIG. 2 is a flowchart for explaining a tire pressure control program used by a computer of the tire pressure control device.

FIG. 3 is another flowchart for explaining the tire pressure control program.

FIG. 4 is a diagram for explaining an example of the tire pressure control.

[Explanation of symbols]

 10 Compressor 18,28 Pressure sensor 22,32 Rotating air seal device 24,34 Manual cock 26,36 Tire inner chamber 42,44,46 Pressure increasing valve 60,62 Pressure reducing valve 70 Pressure control device 72 Controller

Claims (1)

Claim: What is claimed is: 1. An air inlet / outlet of a tire inner chamber, which is an air chamber in a tire of a wheel, is connected to a pressure control device on the vehicle body side via a rotary air seal device provided at the center of the wheel. In the tire pressure control device for performing tire pressure control in which the controller controls the target pressure by increasing or reducing the tire pressure through the pressure control device while monitoring the tire pressure by the pressure sensor, A manually operated on-off valve is provided at a portion of the tire outer chamber, which is an air chamber extending through the rotary air seal device to the pressure control device, on the air inlet / outlet side of the rotary air seal device, and the on / off valve is manually operated. Accordingly, the tire inner chamber and the rotary air seal device may be in either an open state in which they communicate with each other or a closed state in which they are blocked from each other. In the above, the pressure sensor is provided in a portion of the tire outer chamber on the side of the pressure control device with respect to the on-off valve, and the controller controls the pressure reduction speed of the pressure control device during the tire pressure control. When using the pressure sensor to detect, and if the pressure reduction rate is faster than the pressure reduction reference value, the pressure control device is caused to increase the pressure, and the pressure increase speed of the pressure control device at that time is measured using the pressure sensor. A tire pressure control device characterized in that the pressure of the pressure control device is set to atmospheric pressure when the detected pressure increase speed is faster than a pressure increase reference value.