JP4556570B2 - Tire pressure adjusting device - Google Patents

Description

  The present invention relates to a tire air pressure adjusting device that adjusts the air pressure of a tire used in a vehicle such as an automobile by control from the vehicle body side.

  Tires only function when infused with air. If the air is lower than the specified value, there is an influence such as an increase in resistance due to deformation or a decrease in steering performance. On the other hand, if the air pressure is too high, the tire will hardly be deformed, but there will be effects such as increased vibration and poor ride comfort, and a reduced ground contact area.

Therefore, various methods for adjusting the air pressure in the tire from the vehicle body side, such as increasing or decreasing the pressure, have been proposed. For example, Patent Document 1 discloses a mechanism in which an air pressure adjusting valve including a diaphragm valve and a spool valve is installed on the tire side, and a pressure control valve and a pressure release valve are installed on the vehicle body side. This mechanism controls the air pressure adjusting valve to a pressure-increasing, neutral, or pressure-reducing position based on the pressure difference between the air pressure in the tire air chamber and the air pressure supplied from the vehicle body adjusted by the pressure control valve and the pressure release valve. To do. According to this, when the vehicle is stopped, the tire pressure can be controlled arbitrarily or completely automatically from the passenger compartment even when the vehicle is running.
JP-A-4-287705

  As described above, there is disclosed a configuration in which the air pressure adjusting valve provided on the tire side is controlled by a pressure difference instead of electrical control. However, the present inventor further increases the certainty of airtight maintenance of the tire air chamber. I found a way to increase it.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a tire pressure adjusting device that increases the reliability of the airtightness of the tire air chamber.

In order to solve the above-described problem, a tire air pressure adjusting device according to an aspect of the present invention includes a tire air pressure adjusting device that adjusts the air pressure in the tire according to a pressure difference between the air pressure in the tire and the air pressure supplied from the vehicle body. A first block including a valve for pressurizing air pressure in the tire; a second block including a valve for reducing the air pressure in the tire; and a third block for maintaining the air pressure in the tire. And a biasing means for biasing the movable unit integrally formed by the first to third blocks so that the third block is selected in a state where the atmospheric pressure is supplied from the vehicle body side. Depending on the pressure difference between the air pressure in the tire and the air pressure supplied from the vehicle body, one of the first to third blocks is selected by the movement of the movable unit, and the port leading to the tire and the port The selected block is arranged between the port leading to the vehicle body and the block functions.

  According to this aspect, by performing control such as pressure increase by selecting a block, it is possible to increase the certainty of the air tightness holding of the tire air chamber as compared with the case of controlling by moving the position of at least one valve. it can.

Further, According to an aspect of this, by unitizing the blocks corresponding to the increasing pressure, etc., it can be facilitated pneumatic control.

Moreover, according to the aspect of this, in a state in which the vehicle body is the atmospheric pressure is supplied, without providing a mechanism such as a diaphragm valve, it is possible to maintain the state that holds the air pressure in the tire.

In a state where the air pressure supplied from the vehicle body is pressurized from the vehicle body side so that the air pressure supplied from the vehicle body is lower than the air pressure in the tire by a predetermined value, the second block may be selected against the urging means. According to this aspect, the air pressure in the tire can be reduced while being pressurized from the vehicle body side.
A tire air pressure adjusting device according to another aspect of the present invention is a tire air pressure adjusting device that adjusts the air pressure in a tire according to a pressure difference between the air pressure in the tire and the air pressure supplied from the vehicle body side. A first block including a valve for pressurizing the air pressure, a second block including a valve for reducing the air pressure in the tire, a third block for maintaining the air pressure in the tire, and a large block from the vehicle body side. Urging means for urging the movable unit integrally formed by the first to third blocks so that the third block is selected in a state where the atmospheric pressure is supplied. The air pressure in the tire acts on one side of the movable unit, the air pressure supplied from the vehicle body acts on the other side of the movable unit, and resists the biasing means according to the air pressure supplied from the vehicle side. When the movable unit moves, any one of the first to third blocks is selected, and the selected block is arranged between the port leading to the inside of the tire and the port leading to the vehicle body side. Works.

  According to the present invention, it is possible to increase the reliability of the airtight maintenance of the tire air chamber.

  One embodiment of the present invention is a tire air pressure control system that controls an air pressure in a tire to an appropriate value in accordance with a road surface condition or a running condition, and is provided on the tire side, and supplies air from the vehicle body side when pressure is reduced or increased. Provided is a tire pressure adjusting device for receiving air or exhausting air, and otherwise ensuring air tightness of the tire.

  FIG. 1 is an overall configuration diagram of a tire pressure control system 10 according to the present embodiment. A suspension (not shown) is mounted between the vehicle body 12 and each of the wheels 20FR, 20FL, 20RR, 20RL (hereinafter collectively referred to as “wheels 20” as appropriate). The wheel 20 is mainly composed of a wheel and a rubber tire, and a tire air chamber is formed between the wheel and the rubber tire. Note that symbols FR, FL, RR, and RL indicate the positions on the right front, left front, right rear, and left rear, respectively.

  Any one of the wheels 20 is provided with a wheel speed sensor 36 that detects the number of rotations of the wheel. The wheel speed sensor 36 may be provided corresponding to each wheel.

  The wheel 20 is provided with air pressure sensors 22FL, 22FR, 22RR, and 22RL (hereinafter collectively referred to as “air pressure sensor 22” as appropriate) for detecting the pressure in the tire air chamber. Detection signals from the air pressure sensor 22 and the wheel speed sensor 36 are supplied to an electronic control device 80 (hereinafter referred to as “ECU 80”) provided in the vehicle body. The air pressure sensor 22 may be provided in the middle of the air supply line 90 communicating with the tire air chamber instead of being provided in the tire air chamber.

  Rotating air seals 32FR, 32FL, 32RR, and 32RL are provided between the vehicle body 12 and the wheels 20, respectively, so that air can be introduced into the tire air chamber of the wheels 20 from the vehicle body 12 side. The rotating air seal is provided in the hub of the wheel 20 and communicates with an air supply line 90 of the vehicle body 12 and the tire air chamber, and a seal that allows the wheel 20 to rotate while keeping this airtight. It is made of a material (not shown), and air can be supplied into the tire air chamber of the wheel 20 while the vehicle is running.

  At the tip of the rotating air seal 32, tire pressure adjusting devices 30FR, 30FL, 30RR, 30RL for switching the communication state or the blocking state of each wheel 20 with the tire air chamber (hereinafter, these are collectively referred to as "tire pressure adjusting device 30"). Is provided). The detailed structure and operation of the tire pressure adjusting device will be described later.

  In the middle of the air supply line 90 communicating with the rotary air seal 32, tire pressure control valves 42FR, 42FL, 42RR, 42RL corresponding to the wheels 20FR, 20FL, 20RR, 20RL (hereinafter referred to as “tire pressure control valves” as appropriate). 42 ”). The tire pressure control valve 42 is electrically connected to the ECU 80, and can be switched between a valve open state and a valve closed state in accordance with a signal from the ECU 80.

  The vehicle body 12 is provided with a compressor 60 for compressing and supplying air to the air supply line 90. The motor 62 supplies power to the compressor 60. When the motor 62 rotates, air is taken in from the outside through the air inlet 64 and is compressed by the compressor 60. The compressed air flows into the dryer 74. The dryer 74 contains a desiccant such as silica gel, and dries inflowed air and supplies it to the air supply line 90.

  The vehicle body 12 may further include a high-pressure tank 66 that can store compressed air supplied from the compressor 60 and a high-pressure tank valve 68 that controls the flow of air into and out of the high-pressure tank. The high-pressure tank 66 is maintained at, for example, 700 to 800 kPa by sending compressed air from the compressor 60. By supplying the compressed air from both the high-pressure tank 66 and the compressor 60 to the tire air chamber, the responsiveness when the tire pressure is increased can be improved. Therefore, if the capacity of the compressor 60 is sufficient, the high-pressure tank 66 may not be provided in the vehicle body 12.

  The air supplied from the dryer 74 flows into the air supply line 90 communicating with the tire air chamber via the check valve 78. The check valve 78 is opened when air is supplied from the compressor 60 side, and allows air to flow through the air supply line 90, thereby preventing air flow in the reverse direction. An orifice 76 is provided so as to bypass the check valve 78. The air from the air supply line 90 flows into the orifice 76 and then flows into the dryer 74 after the flow velocity is reduced. By doing so, moisture absorbed by the silica gel of the dryer 74 can be reduced. The air that has passed through the dryer 74 is discharged from the silencer 72 through the exhaust valve 70 to the outside of the vehicle.

  FIG. 2 is a block diagram illustrating a configuration of the tire pressure control system 10 according to the present embodiment. The ECU 80 receives the tire air pressure of each wheel 20 detected by the air pressure sensors 22FR, 22FL, 22RR, and 22RL and the wheel speed detected by the wheel speed sensor 36.

  The tire air pressure control system 10 may include an air pressure switching device (not shown) that can select the air pressure in the tire air chamber by a driver's switch operation. A switch 52 is provided. As a result, it is possible to realize driving that meets the driver's preference. On / off information of the air pressure changeover switch 52 is also input to the ECU 80.

  The ECU 80 is electrically connected to a tire pressure control valve 42FR, 42FL, 42RR, 42RL, an exhaust valve 70, a high-pressure tank valve 68, and a motor 62 that drives the compressor 60. The ECU 80 outputs control signals to these control valves and the motor 62 based on the signals from the various sensors and switches described above.

  The internal configuration of the ECU 80 is represented by a functional block diagram. Each block shown here can be realized in hardware by an element and a mechanical device including a computer CPU and memory, and in software by a computer program or the like. It is drawn as a functional block to be realized. Therefore, those skilled in the art will understand that these functional blocks can be realized in various forms by a combination of hardware and software.

  A vehicle speed calculation unit 82 in the ECU 80 calculates the vehicle speed of the vehicle based on the wheel rotation speed detected by the wheel speed sensor 36. The tire air pressure determination unit 86 determines the height of the tire air pressure of each wheel 20 with respect to the target value based on the signal from the air pressure sensor 22. The air pressure control unit 88 sets a target value of tire air pressure in accordance with a switch operation by a driver or a predetermined algorithm. Then, the air pressure control unit 88 appropriately controls the opening and closing of the tire air pressure control valve 42, the high pressure tank valve 68, and the exhaust valve 70 based on the determination result in the tire air pressure determination unit 86, so that the tire air pressure of the wheel 20 is adjusted to the respective values. Try to reach the target value.

  When the tire air pressure is smaller than the target value set by the air pressure control unit 88, the air pressure control unit 88 sends a signal to the motor 62 and the dryer 74 to generate compressed air. At this time, compressed air having a value higher than the air pressure of the tire air chamber is created. The air pressure control unit 88 outputs a signal for opening the high-pressure tank valve 68 in the middle of the passage communicating with the tire air chamber of each wheel. As a result, the air compressed by the compressor 60 and the compressed air accumulated in the high-pressure tank 66 are supplied to the dryer 74, the opened check valve 78, the air supply line 90, the tire pressure control valve 42, and the tire pressure adjusting device 30. Through the tire air chamber and the air pressure rises.

  When the tire air pressure is larger than the target value set by the air pressure control unit 88, the air pressure control unit 88 creates compressed air in the same manner as described above, and supplies the compressed air to the tire air pressure adjusting device 30. At this time, compressed air having a pneumatic pressure adjusted by a method described later is created. Then, air flows out from the tire air chamber through the tire air pressure adjusting device 30, and is discharged from the silencer 72 through the rotating air seal 32, the air supply line 90, and the exhaust valve 70.

  When sealing the tire air chamber, the air pressure control unit 88 opens the exhaust valve 70 to release the air. When the atmospheric pressure is supplied from the vehicle body side, the tire air pressure adjusting device 30 seals the tire air chamber. This detailed configuration will be described later.

  One of the roles of the tire air pressure adjusting device 30 according to the present embodiment is to not apply tire air pressure to the rotating air seal at the normal time when the tire air pressure is not controlled. This is because when the tire air pressure is applied to the rotating air seal, the wear of the seal increases, and the life of the seal decreases. Further, by providing the tire pressure adjusting device 30 on the wheel 20, an electric signal is sent to the tire pressure adjusting device 30 by controlling the compressor and each control valve provided on the vehicle body side with the ECU 80 as will be described later. It is possible to switch the supply, discharge, or sealing of air to the tire air chamber from the side of the vehicle body without the need to provide it and without adding new components to the existing tire pressure control system.

  Hereinafter, the structure and operation of the tire pressure adjusting device 30 will be described with reference to FIGS. 3 to 5.

  FIG. 3 is a diagram showing a configuration of the tire air pressure adjusting device 30 and shows a state when the tire air chamber is sealed without adjusting the air pressure. The movable unit 100 of the tire pressure adjusting device 30 includes a first block 102, a second block 104, and a third block 106. The first block 102 is a block for pressurizing the tire air chamber, and includes a check valve. This check valve opens when air is supplied from the vehicle body side, and prevents the flow of air in the reverse direction.

  The second block 104 is a block for decompressing the tire air chamber, and includes a check valve. This check valve opens when air is supplied from the tire side, and prevents the flow of air in the reverse direction. The third block 106 is a block for blocking the first port connected to the tire air chamber and the second port connected to the air supply line 90 on the vehicle body side and sealing the tire air chamber.

  The movable unit 100 is provided with biasing means 108 and 110 composed of a spring or the like on a housing (not shown) or the like. Further, the pressure of the first port on the tire side acts on the left side surface of any of the blocks and the movable unit 100 described above. On the other hand, the pressure of the second port on the vehicle body acts on one of the above-described blocks and the right side surface of the movable unit 100.

  When the air pressure is not adjusted, that is, when the tire air chamber is sealed, the third block 106 is arranged between the first port and the second port with the second port open to the atmosphere. To do. Specifically, the pressure difference acting on both sides due to the pressure of the first port when the tire air chamber is sealed, and the pressure of the second port when the tire is released to the atmosphere, the size and mass of each block And the characteristics of the urging means 108 and 110 on both sides of the movable unit are set to optimum values. The optimum value can be obtained theoretically, but detailed adjustment may be obtained experimentally. Here, since the tire pressure is higher than the atmospheric pressure in the state where the second port is opened to the atmosphere, the pressure difference is a force that moves the movable unit 100 to the right in the drawing.

  Next, the operation of the tire pressure adjusting device 30 when the tire pressure is increased will be described with reference to FIG. When increasing the tire air pressure, first, the air pressure control unit 88 sends high-pressure air to the second port. Then, the pressure by the air acts on any block and the right side surface of the movable unit 100. When the pressure of the second port becomes larger than the pressure of the first port, a force that moves the movable unit 100 to the left in the drawing works. Further, when the force reaches a predetermined magnitude, the movable unit 100 is moved to the left against the urging means 108 and 110.

  As illustrated, the first block 102 is arranged between the first port and the second port. Since the first block 102 includes a valve communicating from the second port to the first port, high-pressure air can be supplied from the vehicle body side to the tire air chamber.

  Next, the operation of the tire pressure adjusting device 30 when stopping the tire pressure increase will be described. When the tire air pressure reaches a desired pressure, the air pressure control unit 88 stops supplying high-pressure air and opens the second port to the atmosphere. Then, since the first port has a higher pressure than the second port, the movable unit 100 is pushed rightward in FIG. As shown in FIG. 3, the third block 106 is arranged between the first port and the second port. When the supply of high-pressure air is stopped in this way, the tire air chamber is kept airtight.

  Next, with reference to FIG. 5, the operation of the tire pressure adjusting device 30 when the tire is depressurized will be described. When the tire pressure is reduced, the air pressure control unit 88 sends high-pressure air to the second port so that the air pressure of the second port is lower than the air pressure of the first port by a predetermined value. Then, the first port becomes higher in pressure by the predetermined amount than the second port, and the movable unit 100 is pushed rightward from the state of FIG. Then, as shown in FIG. 5, the movable unit 100 moves to the right by one block, and the second block 104 is arranged between the first port and the second port. Since the second block 104 includes a valve communicating from the first port to the second port, the air in the tire air chamber can be discharged.

  In other words, the pressure difference is such that the movable unit 100 maintains the second block 104 at a position between the first port and the second port against the biasing means 108 and 110. Necessary between the second port. This pressure difference is set to the predetermined value. When the air pressure control unit 88 recognizes that the tire air pressure has been reduced from the detection value of the air pressure sensor 22, it sends a control signal to the motor 62 and the dryer 74 so as to reduce the air supplied to the port 2 correspondingly. . Further, control signals are also sent to the high-pressure tank valve 68 and the exhaust valve 70 as necessary. In this way, the second block can be maintained between the first port and the second port by always controlling the pressure difference to be constant.

  The operation of the tire pressure adjusting device 30 when stopping the pressure reduction of the tire pressure is the same as the procedure for stopping the pressure increase.

  Next, a specific design example of the movable unit 100 will be described. Usually, the pressure range of the tire air chamber is about 180 to 350 kPa. Since the movement of the movable unit 100 is controlled by the pressure on the port 2 side, a certain pressure difference is required between the port 1 and the port 2. For example, assuming that the accuracy of the air pressure sensor 22 is about ± 10 kPa, it is sufficient that the differential pressure is about 100 kPa, which is ten times that of the above pressure difference.

Here, the pressure difference at the time of pressurization and pressure reduction is 100 kPa. The radius of the valve is 2 mm. The stroke of each block 102, 104, 106 is 10 mm. k represents the spring constant of the springs as the biasing means 108 and 110.
10k = 1/100 × 2 ² π
k = 1.3 × 10 ⁻⁴ k [kg / mm]

  As described above, according to the tire pressure adjusting device according to the present embodiment, the air to the tire air chamber can be controlled only by controlling the air pressure on the vehicle body side without sending an electrical control signal to the tire pressure adjusting device. Supply, air discharge, and airtight state during non-control can be switched. In general, since the tire pressure adjusting device rotates on the axle together with the wheels, if an electrical control means is attached thereto, the control system becomes very complicated and the possibility of causing a failure increases. It is preferable not to use such electrical means.

  Further, it is not necessary to provide a diaphragm valve unlike the conventional tire pressure adjusting device. By switching the valve in units of blocks and performing control such as pressure increase, the certainty of maintaining the airtightness of the tire air chamber is increased as compared with the case of controlling by moving one valve. Also, a check valve can be used, further increasing its certainty. In addition, it is resistant to aging.

  The present invention has been described above based on the embodiment. It should be understood by those skilled in the art that these embodiments are exemplifications, and that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention. Hereinafter, such modifications will be described.

  The arrangement of the first block 102, the second block 104, and the third block 106 constituting the movable unit 100 is not limited to that described above. In any arrangement, the air pressure of the second port corresponding to the arrangement may be adjusted.

1 is an overall configuration diagram of a pneumatic control system according to an embodiment of the present invention. It is a functional block diagram of a tire pressure control system. It is a figure which shows the state of the tire pressure adjusting device when holding a tire pressure. It is a figure which shows the state of the tire pressure adjusting device when increasing a tire pressure. It is a figure which shows the state of the tire pressure adjusting device when reducing a tire pressure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Tire pressure control system, 22 Air pressure sensor, 30 Tire pressure adjusting device, 32 Rotating air seal, 42 Tire pressure control valve, 68 High pressure tank valve, 70 Exhaust valve, 80 ECU, 88 Air pressure control part, 90 Air supply line, 100 Movable Unit, 102 first block, 104 second block, 106 third block, 108, 110 biasing means.

Claims (3)

A tire pressure adjusting device that adjusts the air pressure in the tire according to the pressure difference between the air pressure in the tire and the air pressure supplied from the vehicle body side,
A first block including a valve for pressurizing air pressure in the tire;
A second block including a valve for reducing the air pressure in the tire;
A third block for maintaining air pressure in the tire;
An urging means for urging a movable unit integrally configured by the first to third blocks so that the third block is selected in a state where atmospheric pressure is supplied from the vehicle body side;
Depending on the pressure difference between the air pressure in the tire and the air pressure supplied from the vehicle body, one of the first to third blocks is selected and communicated with the tire by moving the movable unit. A tire pressure adjusting device, wherein the selected block is arranged between a port and a port communicating with the vehicle body, and the block functions. A tire pressure adjusting device that adjusts the air pressure in the tire according to the pressure difference between the air pressure in the tire and the air pressure supplied from the vehicle body side,
A first block including a valve for pressurizing air pressure in the tire;
A second block including a valve for reducing the air pressure in the tire;
A third block for maintaining air pressure in the tire;
An urging means for urging a movable unit integrally configured by the first to third blocks so that the third block is selected in a state where atmospheric pressure is supplied from the vehicle body side;
The air pressure in the tire acts on one side surface of the movable unit, and the air pressure supplied from the vehicle body side acts on the other side surface of the movable unit,
According to the air pressure supplied from the vehicle body side, when the movable unit moves against the biasing means, any one of the first to third blocks is selected, and a port communicating with the tire The tire pressure adjusting device, wherein the selected block is disposed between a port communicating with the vehicle body and the block functions.   The second block is selected against the biasing means in a state where the air pressure supplied from the vehicle body side is pressurized from the vehicle body side so as to be lower than the air pressure in the tire by a predetermined value. The tire pressure adjusting device according to claim 1 or 2, characterized in that

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