JP2673620B2 - Tire pressure control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire pressure control device capable of automatically controlling a tire pressure of a wheel from a vehicle body side while a 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 by reducing the.

[0002]

2. Description of the Related Art A tire pressure control device is generally used in Japanese Utility Model Laid-Open Sho 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 the controller is configured to perform tire pressure control for monitoring the tire pressure with a pressure sensor and increasing or decreasing the tire pressure via the pressure control device to control the target tire 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 the wheel and a non-rotating member. Therefore, it is usually composed mainly of an air seal including a rubber lip.

[0003]

In the tire pressure control device of this type, 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, research by the applicant has 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 always 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]

[Means for Solving the Problems] As a problem, follow the present invention
The tire pressure control device is (a) installed in the center of the wheel.
And a rotating air seal device installed on the car body (b)
A pressure control device for controlling the pressure of air, (c) the tire
The inner chamber and the pressure control device are provided with the rotary air seal device.
Air passages that connect to each other via a rotating air seal
The device separates the wheel side partial passage and the vehicle body side partial passage.
(D) provided on the wheel side partial passage, and manually
Depending on the operation, the tire inner chamber and the rotary air seal device
The open state that allows the device to communicate with each other, and they are isolated from each other
An on-off valve that switches to a closed state that
Of the pressure control device from the position where the on-off valve is arranged
It is provided in the part of and detects the pressure of the air in that part.
Pressure sensor, (f) the pressure sensor and the pressure control device
Connected to and the pressure detected by the pressure sensor is the target
A controller that controls the pressure control device to be equal to the pressure.
Controller, the controller depressurizes the pressure control device.
Pressure is detected by the pressure sensor during operation
However, the depressurization rate, which is the rate of change of the detected pressure, is
When the decompression standard value is exceeded, which is not exceeded when the on-off valve is open
Stops the depressurization operation and increases the pressure.
The pressure is detected by the pressure sensor during operation and the detected pressure
The pressure increase rate, which is the rate of change of force, is too high when the on-off valve is open.
If the pressure increase reference value is exceeded, the pressure increase operation is stopped.
A controller that controls the pressure of the pressure control device to atmospheric pressure
It is solved by including and.

[0006] Incidentally, the opening and closing valve is a common to connect to the air inlet and outlet in the chamber tires, for example, a rotary air seals device, etc. connected to the air inlet and outlet of the tire in the chamber side, et
(A) It can be connected to any position of the passage on the air inlet / outlet side of the rotary air seal device.

[0007]

The control pressure chamber to which the pressure of the pressure control device acts is an air chamber that 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 open / close valve is in the closed state than when the open / close valve 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 these facts, in the tire pressure control device according to the present invention, the pressure reducing speed of the pressure control device at the time of tire pressure control is based on the output signal of the pressure sensor.
If the pressure reduction rate is faster than the pressure reduction reference value, the on-off valve is expected to be in the closed state immediately, the tire pressure control is stopped, and the pressure of the pressure control device is set to atmospheric pressure. The pressure control device is operated to increase pressure,
At that time, the pressure increasing speed of the pressure control device is the pressure sensor.
It is detected based on the output signal, the first time when the pressure increase rate is higher than the pressure increase reference value, the on-off valve is expected to be in the closed state, the pressure of the tire pressure control is stopped by the pressure control device atmospheric pressure It is said that 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.

[0009] Incidentally, "controller" in the present invention are, for example, pressure increase rate of the pressure of the pressure control device when the tire pressure control (described above, different from the pressure increase rate when decompression speed is higher than the reduced pressure reference value) Is faster than the pressure increase reference value, the pressure of the pressure control device can be immediately set to the 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 can be 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 in the closed state, the tire pressure control is stopped, the pressure of the pressure control device is set to atmospheric pressure, and the rotary 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 in the closed state, the tire pressure control is not hunted and the pressure control device is not frequently operated in vain. You can also get the effect. The volume of the control pressure chamber in 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 in the control pressure chamber changes sensitively, and pressure control is caused due to response delay of the solenoid valve, pressure sensor, etc. Hunting can cause 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 ensured in the tire inner chamber as long as the open / close valve is in the closed state, and thus a normal tire pressure is maintained. 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. In FIG. 1, 1
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 air passage 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 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.
And, it goes to 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 connected to air inlets and outlets (not shown) of the tire inner chambers 26 and 36, respectively. 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 moisture 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 provided. The pressure increasing valve 42 is always closed, but it is opened when the solenoid is excited 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 type 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 the 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 against the valve seat is diminished, and the sealing performance is slightly reduced.

Since the pressure boosting valves 42 to 46 have such a one-way self-sealing property, the pressure boosting 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 to 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 the tire inner chambers 26, 36 side to 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, 36 side and the compressor 10 side are reliably shut off from each other. By the way, the compressor 10 not only functions as a pressure source for tire pressure control, but also as a pressure source for a vehicle air brake. Therefore, the bidirectional self-sealing property is realized by the pressure increase valves 42 to 46, so that both the securement of the tire pressure and the securement of the air brake force are reliably ensured. In the figure, the broken lines with arrows attached to the pressure increasing valves 42 to 46 indicate the direction of self-sealing.

Each pressure boosting valve 4 in 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 through 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 each tire inner chamber 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, realize one-way self-sealing property 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
The pressure control device 70 is constituted by the and. Also,
Regarding the right wheel, the air passage 50 of the air passage 16
This is mainly due to the part that connects the connection point of the
An example of the "air chamber" in Ming is constructed, and for the left wheel , the connection point of the air passage 18 with the air passage 52 and the
The part that connects the ear inner chamber 36 with another
An example is constructed.

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 tire pressure is connected to the controller 72. The target pressure setting means 74 has a select switch operated by the driver of the vehicle and switches the setting of the target pressure into three steps of high / medium / low, and the height according to the operation 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 so that the tire pressure becomes the target pressure while monitoring the tire pressure (correctly, the pressure detected by the pressure sensors 18 and 28) by the pressure sensors 18 and 28. , Pressure increase valves 42-46
And controlling the pressure reducing valves 60, 62.

The state of the tire pressure control will be described below with reference to FIG.
Of the pressure increasing mode, the flow chart of the pressure reducing mode of FIG. 3, and the example of the change of the operating state of each operating component in FIG. 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 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 target pressure is changed by the select switch, and immediately after it is determined that the manual cocks 24 and 34 have been moved from the closed state to the open state ( The determination will be described later in detail) and 10 in all other cases. 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 the road surface unevenness are used to determine the target range. The target range is widely set in consideration of variations in tire pressure due to input to the tire.

If the tire pressure is within the target range, the controller 72 keeps the pressure increasing valve 42 or the like as it is, and maintains the tire pressure. On the other hand, if 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. In addition, 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 energizes the pressure increasing valves 42 to 46. Switch to the open state.
As a result, high-pressure air is transferred to the pressure increasing valve 42 and each pressure increasing valve 44,
The tire pressure of each wheel is increased by being supplied to each of the tire inner chambers 26, 36 through 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 pressure increase amount during that period by the constant time.

The pressure increasing speed of the pressure control device 70 is such that the tire does not burst and the tire pressure control device (to be exact, the compressor 10 and the manual cocks 24, 34).
There is no air leak (hereinafter, simply referred to as “air leak”) in the air passage between and, and when the manual cocks 24 and 34 are in the open state, they are faster than the lower limit reference speed (0) and the upper limit reference speed. although (positive value) or less, there is no air leakage, and faster than the upper limit reference speed when the manual cock 24 and 34 is in the closed state, also, there manual cock 24 and 34 in the open state If the tire is bursting or there is air leak, the speed will be less than the lower limit reference speed. this child
The same applies to the depressurization rate. That is, this implementation
In the example, the upper limit reference speed of the pressure increasing rate is set in the present invention.
This is an example of the "pressure increase reference value", which is the upper limit reference speed of the pressure reduction speed.
The degree is an example of the “decompression reference value”. In addition, pressure control
The pressure of the device 70 is detected by the pressure sensors 18 and 28.
Pressure is the same, but the manual cocks 24 and 34 are closed
Since it does not always match the tire pressure,
In order to distinguish it from the tire pressure by taste, it is called the control pressure below.
U.

Regarding the tire pressure control this time, assuming that the manual cocks 24, 34 are in the open state (no air leakage or tire burst), this time the pressure increase speed is equal to the upper limit reference speed and the lower limit reference speed. If it is in between (in FIG. 2,
It is determined to correspond to (in the case of “normal”). In this case, the pressure increase valves 42 to 46 are kept open even after that, and the tire pressure is increased. After the completion 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 waits for a fixed time (for example, 1 second) to elapse. It waits until the air flow between the pressure boosting 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 (the 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 procedure returns to the above-described step for 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 If is determined to be 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.

If it is assumed that the manual cocks 24 and 34 are open this time (no air leak or tire burst),
This time, it is determined to correspond to the case where the decompression speed is between the lower limit reference speed and the upper limit reference speed (indicated by “normal” in FIG. 3). After that, the controller 72 determines whether or not the tire pressure is within the control range, as in the case of the pressure increase mode. Then, if it is determined that the tire pressure is within the control range, the process returns to the step of determining 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) 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 increasing 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. . After that, the tire pressure is measured and the magnitude is determined in the same manner as in the case of increasing the pressure.

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 (correctly, the control pressure ) is within the target range, and if the control pressure is determined to be less than the target range, increase the pressure. When it is determined that the mode is larger than the target range, the pressure reducing mode is entered.

If the pressure increasing mode is entered, the controller 7
2, the pressure increase rate is calculated and the magnitude of the pressure increase rate is determined in the same manner as in the previous case, but this time, the manual cock 24,
Since it is assumed that the valve 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 is determined to be in the closed state, the pressure increase valves 42 to 46 are demagnetized to return to the closed state to stop the current pressure increase operation (stop the current tire pressure control), and the compressor 10 is turned on. Turn off. Further, the pressure reducing valves 60, 6
2 is opened for a certain time (for example, 1 to 2 seconds) to reduce the control pressure to atmospheric pressure.

The control 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 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
Would always be under pressure. Therefore, in this embodiment, when it is determined that the manual cocks 24, 34 are in the closed state, the pressure reducing valves 60, 62 are opened to reduce the control pressure to the 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, it is determined that the case corresponds to the case where the depressurization speed is faster than the upper limit reference speed (indicated by “sudden drop” in FIG. 3). However, in this case, unlike the case of the pressure increasing mode, the controller 72 immediately causes the manual cock 2 to
It is not determined that 4, 34 are in the closed state. Specifically, the controller 72 shifts to the pressure increasing mode described above 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. If the pressure increase rate is faster than the upper limit reference speed, the manual cocks 24, 34 are in the closed state, and the air leakage If it is determined that the pressure increase rate is not higher than the lower limit reference speed, it is determined that the manual cocks 24 and 34 are in the open state and the tire is bursting or there is air leakage.

After it is determined that the manual cocks 24, 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, 28. It is periodically determined whether or not it has risen above a predetermined release pressure (for example, 50 [kPa]). When it is determined that the control pressure does not rise above the release pressure, the controller 72 determines that the manual cock 2
It is determined that the tires 4, 4 and 34 are kept closed, and the tire pressure control this time is continuously stopped. However, if it is determined that the control pressure has risen to the release pressure or more, the manual cocks 24 and 34 are opened. The determination is returned to the determination step of whether the tire pressure is within the target range, and the tire pressure control this time is restarted from there.

After the manual cocks 24 and 34 are determined to be in the closed state and the control pressure is reduced to the atmospheric pressure, the control pressure is reduced by minute air leakage from the manual cocks 24 and 34 or the pressure increasing valves 42 to 46. May rise from atmospheric pressure. In this case, if 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 increasing speed, 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, 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 source is turned on. If the depressurization 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 pressure changing speed.
If the open / closed state of the pressure controller 70 is determined, and if it is determined that the pressure controller 70 is in the closed state, the variable pressure operation of the pressure control device 70 is stopped to prevent hunting of the pressure control. As a result, the durability of the tire pressure control device is improved, and the reliability of the tire pressure control device is improved.

Further, 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 high , and pressure increasing is performed instead of pressure reducing.
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 misidentification of the fact that the vehicle is in the closed state.

Further, in this embodiment, if it is determined that the manual cocks 24, 34 are in the closed state, the pressure control device 70 is depressurized and the control pressure thereof is reduced to the atmospheric pressure. Since 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. You can also get the effect.

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, so that the driver of the vehicle operates the manual cock 2
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 4, 34 and the pressure control device 70 excessively. 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, hunting is prevented without increasing the volume of the air chamber, so that there is an effect that neither the installation space of the tire pressure control device nor the device cost is increased.

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

Although 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 the 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

Continuation of the front page (56) Reference JP-A-1-156110 (JP, A) JP-A-3-67711 (JP, A) JP-A-2-106412 (JP, A) JP-A-2-74406 (JP , A)

Claims (1)

(57) [Claims] 1. A device for controlling a pressure in a tire inner chamber, which is an air chamber in a tire of a wheel, from a vehicle body side, wherein a rotary air seal device provided in the center of the wheel and an air chamber provided in the vehicle body. Pressure control device to control pressure
And the tire inner chamber and the pressure control device with the rotary air shield.
Air passages that connect to each other via the
Partial passage on the wheel side and partial passage on the vehicle body side by the air seal device
It is provided on the wheel side partial passage and is divided according to manual operation.
Communication between the tire inner chamber and the rotary air seal device
Between open and closed to shut them off from each other.
The switching valve and the pressure from the position where the switching valve is installed in the air passage.
It is provided in the part on the side of the control device, and the pressure of the air in that part
A pressure sensor for detecting force , connected to the pressure sensor and the pressure control device,
Make sure that the pressure detected by the sensor is equal to the target pressure.
A controller for controlling the pressure control device,
If the controller is causing the pressure control device to perform depressurization
Of the detected pressure
The decompression rate, which is the rate of change, is too high when the on-off valve is open.
If the decompression standard value is exceeded, the decompression operation is stopped.
To increase the pressure, and the pressure sensor
More pressure is detected and the rate of change of the detected pressure is increased.
The pressure speed exceeds the pressure increase reference value that does not exceed when the on-off valve is open.
If the pressure rises, the pressure boosting operation is stopped and the pressure control device
A tire pressure control device comprising: a controller for setting a pressure to atmospheric pressure .