JP2748292B2 - Air brake device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air brake device for a vehicle having an auxiliary brake.

[0002]

2. Description of the Related Art A conventional vehicle converts kinetic energy into frictional energy at the time of braking and radiates it to the atmosphere. However, in order to save energy and reduce exhaust gas, a braking energy regeneration system that utilizes braking energy at the time of deceleration of the vehicle and reuses it when starting and accelerating is being developed for practical use.

FIG. 1 shows an example of the configuration of a pressure-accumulation type braking energy regeneration system, in which a hydraulic pump / motor 3 is connected to an axle 1 via a gearbox 2 and one port 3a of the hydraulic pump / motor 3 is operated. Oil tank 4 with other port 3
b is connected to an accumulator 6 via a switching valve (return valve) 5, and the tilt angle of the hydraulic pump / motor 3 is controlled by the control unit 9 according to the brake signal from the brake pedal 7 and the accelerator pedal 8 and the accelerator signal ( And the switching valve 5 is controlled. Thus, the braking energy regeneration system 10 is configured.

When the brake pedal 7 is depressed during braking,
The control unit 9 controls the tilt angle of the hydraulic pump / motor 3. The hydraulic pump / motor 3 is driven by wheels to operate as a pump, pumps oil from a hydraulic oil tank 4 to an oil chamber 6a of an accumulator 6 through a switching valve 5, and presses a piston 6b leftward in the figure to generate gas. The nitrogen gas (N ₂ ) sealed in the chamber 6c is compressed. Thereby, the kinetic energy of the vehicle at the time of braking is accumulated in the accumulator 6 via the hydraulic pressure. At this time, the braking energy regeneration system 10 functions as an auxiliary brake.

At the time of starting and accelerating, the control unit 9 detects the starting operation of the driver such as the transmission gear position, the stepping amount of the clutch pedal, the accelerator opening, etc., and opens the switching valve 5 and the hydraulic pump / motor 3.
The tilt angle of the motor is controlled, the oil accumulated in the accumulator 6 is caused to flow in the direction opposite to the braking, the torque is generated by the hydraulic pump / motor 3 to be a hydraulic motor, and the wheels are driven to generate an engine. Assist power. This allows
NO _X in the exhaust gas during start and acceleration, improvement of reduction and fuel consumption of CO ₂ and black smoke can be reduced. The braking energy regeneration system 10 is effective for a route bus or the like that travels in an urban area where starting and stopping are frequently performed.

FIG. 2 shows an air brake device of the braking energy regenerating system (hereinafter referred to as "auxiliary brake") 10 and a service brake (main brake) 15. When the brake pedal 7 is depressed, the amount of depression depends on the amount of depression. Air pressure is supplied from the air tank 12 to the differential pressure valve 13 through the brake valve 11 that opens. A bypass passage 31 is provided in the differential pressure valve 13, and a bypass valve (on-off solenoid valve) 19 for opening and closing the bypass passage 31 is connected in the middle of the bypass passage 31. The differential pressure valve 13 opens when the air pressure at the input port 13a becomes higher than the air pressure at the output port 13b and the differential pressure exceeds a set pressure. The bypass valve 19 is opened when not energized and closed when energized. An exhaust valve 22 is provided on the input side of the air master 16.
The valve is opened when not energized and closed when energized.

When the stepping speed of the brake pedal 7 in the initial stage of stepping is high, the control unit 9 deactivates the bypass valve 19 to open the bypass passage 31 and the differential pressure valve 1
3, the air pressure is supplied to the air master 16 to operate the service brake 15 and the exhaust valve 2
2 is performed. That is, the control unit 9
When the bypass passage 31 is open, the exhaust valve 22
Is closed to shut off the air passage 32 from the atmosphere. Thus, the air pressure discharged from the brake valve 11 is supplied to the air master 16 through the bypass passage 31 and the air passage 32, and the main brake device 17 operates. That is, the service brake 15 operates to decelerate the vehicle.

When the depression of the brake pedal 7 becomes constant,
The control unit 9 biases the bypass valve 19 to close the bypass passage 31. That is, the control unit 9 is supplied with sensor signals from the pressure sensor 21 provided on the input side of the Eamasuta 16, the air pressure P ₂ is greater than the preload P ₃ to be imparted to the air passage 32 ( When P ₂ > P ₃ ), the exhaust valve 22 is opened, the air pressure in the air passage 32 is exhausted to the atmosphere, and the auxiliary brake 10
Activate Thereafter, the control unit 9 closes the exhaust valve 22 when the air pressure in the air passage 32 is discharged and decreases to satisfy P ₂ ≦ P ₃ .

[0009]

By the way, in the brake system configured as described above, the control unit 9
In the early stage of the depression of the brake pedal 7, the exhaust valve 22 is closed and the service brake 15 is mainly operated. Then, when the depression of the brake pedal 7 becomes constant, the exhaust valve 22 is opened and the auxiliary brake 10 is opened. Is mainly operated to reduce the working ratio of the service brake 15 and increase the braking force of the auxiliary brake 10. However, since the exhaust valve 22 is electrically controlled by the control unit 9 and is connected to the air passage 32 on the input side of the air master 16, the exhaust valve 22 fails and the exhaust valve 22 If the valve remains open when it must be closed, the air pressure will not be supplied to the air master 16 and the service brake 15 will not operate.

[0010] The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an air brake device capable of always ensuring operation of a service brake.

[0011]

In order to achieve the above object, an air brake device according to the present invention includes an auxiliary brake in addition to a service brake operated by a brake pedal, and a brake operated by the brake pedal. A differential pressure valve is provided between the valve and the air master of the service brake, and a bypass valve is provided in a bypass passage that bypasses the differential pressure valve, while an exhaust valve is connected to an input side of the air master, and according to a depression state of a brake pedal,
In the air brake device, which controls the opening and closing of the bypass valve and the exhaust valve so as to vary the ratio contributing to the control of the auxiliary brake and the service brake, a control is provided between the input side of the air master and the exhaust valve. A valve is provided, and the control valve receives supply of air pressure from an outlet of the brake valve, and when the air pressure reaches a predetermined pressure or more, shuts off the flow of air from the air master to the exhaust valve.

[0012]

According to the control valve of the present invention, the air pressure of a predetermined pressure is supplied from the outlet side of the brake valve to cut off the flow of the air pressure from the inlet side of the air master to the exhaust valve.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIGS. The same members as those in FIG. 2 are denoted by the same reference numerals. In FIG. 3, an input port of the brake valve 11 of the air brake device is an air tank 12.
The output port is connected to the input port 13a of the differential pressure valve 13 by an air passage 30. The output port 13b of the differential pressure valve 13 is connected to the air master 16 of the service brake 15 through the bypass valve 20 and the air passage 32. It is possible. The air master 16 is connected to the main brake device 17.

The air passage 30 is provided with a pressure sensor 14, and the differential pressure valve 13 is provided with a bypass passage 31. The bypass passage 31 has one end connected to the air passage 30 downstream of the pressure sensor 14, and the other end connected to the air master 16 via the bypass valve 20 and the air passage 32. Pressure sensor 14, bypass valve 20
Is connected to a control unit (C / U) 9, which has an auxiliary brake 10
Are electrically connected.

The brake valve 11 is connected to the brake pedal 7
The valve is opened in accordance with the amount of depression of the valve, and the air pressure in the air tank 12 is supplied to the air passage 30. The differential pressure valve 13 is connected to the input port 1
When the air pressure of the air master 3a becomes higher than the air pressure of the output port 13b and the differential pressure exceeds the set pressure, the valve opens and the air master 1
Air pressure is supplied to the 6 side. The air master 16 drives the main brake device 17 according to the air pressure supplied from the air tank 12 to apply a braking force to the wheels. Pressure sensor 1
4 detects the air pressure (primary-side air pressure) P ₁ in the air passage 30, outputs a corresponding sensor signal (brake signal), and supplies it to the control unit 9.

The bypass valve 20 is a 4-port, 2-position electromagnetic directional switching valve, which is controlled by the control unit 9 to be switched to the rest position 20A by the spring force of the return spring when the solenoid 20s is deenergized. When 20s is energized, it is switched to the operating position 20B. When the bypass valve 20 is switched to the rest position 20A, the output port 1 of the differential pressure valve 13
3b and the bypass passage 31 and the air master 1
6 is switched to the operating position 20B, the output port 13b of the differential pressure valve 13 and the air master 16 are connected, and the bypass passage 31 is closed.

A pressure sensor 21 is provided in an air passage 32 connecting the discharge port of the bypass valve 20 and the input port of the air master 16. The pressure sensor 21 detects the air pressure (secondary air pressure) P ₂ supplied to the air master 16.
And supplies a corresponding sensor signal to the control unit 9. The exhaust valve 22 is connected to the air passage 32 via a control valve 23.
Air pressure P ₂ of 2 is adapted to be adjusted. This exhaust valve 22 is an electromagnetic on-off valve, and its solenoid 22s is
It is connected to the control unit 9. When the solenoid 22s is deenergized, the exhaust valve 22 is switched to the rest position 22A to shut off the air passage 32 from the atmosphere. When the exhaust valve 22 is energized, the exhaust valve 22 is switched to the operating position 22B and changes the air passage 32 to the atmosphere. Communicate.

The control valve 23 is connected to the control port 2
3a is connected to the middle of the bypass passage 31 on the outlet side of the brake valve 11 via the air passage 34, and is connected to the input port 23b.
Is connected to the air passage 32 on the inlet side of the air master, and the output port 23 d is connected to the exhaust valve 22. The control valve 23 closes the input port 23b and the output port 23d when the air pressure supplied to the control port 23a becomes equal to or higher than the set pressure, and closes the exhaust valve 22 from the air passage 32.
Air passage 33 leading to the control port 23a.
If the air pressure supplied to the
3b and the output port 23d are opened to open the air passage 32.
The air passage 33 from the to the exhaust valve 22 is opened.

Here, an example of the control valve 23 will be described with reference to FIG. As shown in FIG. 4, the control valve 23 includes a valve housing, and the control port 23a and the input port 23 described above are provided in the valve housing.
In addition to b and the output port 23d, a fourth port 23c is provided, and the fourth port 23c is connected to the air passage 32. A first cylinder hole 40 connected to the control port 23a and a second cylinder hole 41 connected to the fourth port 23c are formed in the valve housing. A third cylinder hole 42 is formed between the first cylinder hole 40 and the second cylinder hole 41. One opening of the third cylinder hole 42 is positioned so as to protrude into the first cylinder hole 40, and the other opening end is connected to the second cylinder hole 41. The first cylinder hole 40 communicates with the output port 23d, and the third cylinder hole 42 communicates with the input port 23b.

In the first and third cylinder holes 40 and 42,
A piston mechanism is housed, and this piston mechanism
As shown in FIG. 4, mainly the piston 43 and the piston spring 4
It consists of four. The piston 43 has a large piston portion 43.
a and a small piston portion 43b, and the small piston portion 43b is formed of a tubular body. A hole 46 penetrating in the radial direction of the small piston portion 43b is provided in a portion where a step is formed between the small piston portion 43b and the large piston portion 43a. The large piston portion 43a of the piston 43 is O
The small piston portion 43b is also fitted into the third cylinder hole 42 via the O-ring 48 via the ring 47. The piston 43 can slide up and down in the first and third cylinder holes 40 and 42. The distal end on the opening end side of the small piston portion 43b has a smaller diameter than the third cylinder hole 42. The piston 43 is normally positioned on the control port 23a side by being pushed by the piston spring 44, and at this time, the open end of the small piston portion 43b is slightly before the other open end of the second cylinder hole 41. And is not in contact with a valve body 50 of a valve body mechanism described later.

On the other hand, a valve body mechanism is accommodated in the second cylinder hole 41 of the fourth port 23c. The valve body mechanism includes a valve body 50 and a valve body spring 51, and the valve body 50 is
Normally, a valve opening formed between the second cylinder hole 41 and the third cylinder hole 42 is closed by being pushed by the valve body spring 51. The valve body 50 is in contact with the open end of the small piston portion 43b of the piston 43 and can be pushed down. In FIG. 4, reference numeral 52 denotes a stopper of the valve body 50.

When the control pressure (air pressure) supplied to the control port 23a is lower than the predetermined pressure Ps, the control valve 23 pushes the piston 43 of the piston mechanism upward by the piston spring 44 to move in the direction of the control port 23a. The small piston portion 43b is connected between the input port 23b and the output port 23d from the open end of the small piston portion 43b through the internal passage, the hole 46, and the first cylinder hole 40. The control pressure (air pressure) of the control port 23a is equal to the predetermined pressure Ps.
Then, the piston 43 is pushed down, the open end of the small piston portion 43b is brought into contact with the valve body 50 of the valve body mechanism, the open end is closed, and the connection passage from the input port 23b to the output port 23d. Is shut off. When the piston 43 is further pushed down, the hole 46 of the small piston portion 43b is immersed in the third cylinder hole 42 and closed.

The opening and closing operation of the control valve 23 described above is clear from the graph shown in FIG.
When the control valve 23 moves from the closed state to the open state,
There is a hysteresis effect due to the relationship between the valve body 50 and the open end of the small piston 43b. When a sensor signal is supplied from the pressure sensor 14, the control unit 9 controls the auxiliary brake 10 and controls the bypass valve 20. The control unit 9 obtains a change amount of the air pressure discharged from the brake valve 11, that is, a stepping speed of the brake pedal 7 based on a change in the sensor signal from the pressure sensor 14, and the stepping speed is slow and smaller than a predetermined value. Sometimes, the bypass valve 20 is urged to close the bypass passage 31,
When the stepping speed is higher than a predetermined value, the bypass valve 20 is deenergized and the bypass passage 31 is opened.

The control unit 9 controls the exhaust valve 22 based on a sensor signal from the pressure sensor 21 to control the air pressure P ₂ in the air passage 32 to a predetermined pressure P ₃ . The predetermined pressure P ₃ is a pre-pressure P ₃ for reducing the response delay of the service brake 15 when the brake pedal 7 is further depressed, and is a low air pressure of, for example, about 0.1 to 0.4 kg / cm ² .

The brake valve 11 is provided for the brake pedal 7
Is closed when is released, and the pressure sensor 14 does not output a signal. The control unit 9 holds the auxiliary brake 10 in a non-operating state and deenergizes the bypass valve 20. Bypass valve 20
Is switched to the rest position 20A (FIG. 3) when the power is deenergized, the output port 13b side of the differential pressure valve 13 is closed, and the bypass passage 31 is connected to the air master 16.

When the brake pedal 7 is depressed, the brake valve 11 opens in response to this, and the air pressure in the air tank 12 is supplied to the air passage 30. Pressure sensor 14
Detects the air pressure on the primary side and supplies a corresponding sensor signal to the control unit 9. The control unit 9 activates the auxiliary brake 10 in response to a sensor signal supplied from the pressure sensor 14 to start recovery of braking energy, and at the same time, urges the bypass valve 20 to switch to the operating position 20B and shuts off the bypass passage 31. Then, the output port 13b of the differential pressure valve 13 and the air passage 32 are connected. The service brake 15 does not operate until the differential pressure valve 13 is opened, and a braking force is applied only by the auxiliary brake 10.

When the depression speed of the brake pedal 7 in the initial stage of the depression is high, the control unit 9 deactivates the bypass valve 20 to open the bypass passage 31, and the differential pressure valve 1
The air pressure is directly supplied to the air master 16 by bypassing 3 to immediately activate the service brake 15 and control the exhaust valve 22. That is, when the bypass passage 31 is open, the control unit 9
The exhaust valve 22 is switched to the rest position 22A and closed, and the air passage 32 is shut off from the atmosphere. As a result, the air pressure discharged from the brake valve 11 is supplied to the air master 16 through the bypass passage 31 and the air passage 32 without escaping to the atmosphere, and the main brake device 17 operates, that is, the service brake 15 operates to decelerate the vehicle. Is done.

When the depression of the brake pedal 7 is constant, the control unit 9 urges the bypass valve 20 to close the bypass passage 31. Thereafter, the control unit 9, the secondary-side air pressure P ₂ is greater than the preload P ₃ to be given to the air passage 32 when (P _2>
P ₃ ), the exhaust valve 22 is urged to switch to the operating position 22B, and the valve is opened, and the air pressure in the air passage 32 (secondary air pressure)
P ₂ is discharged to the atmosphere via the control valve 23. Further, when the air pressure in the air passage 32 is discharged and reduced to P ₂ ≦ P ₃ , the control unit 9 closes the exhaust valve 22 and ends the control of the air brake device.

Even if the exhaust valve 22 fails and must be in the open state when it must be in the closed state,
When the depression of the brake pedal 7 becomes constant and the bypass valve 20 is switched to the operating position 20B, the brake valve 1 is connected to the control port 23a of the control valve 23.
1, the air pressure supplied from the outlet side through the air passage 34 can be raised, and when this air pressure, that is, the control pressure becomes equal to or higher than a predetermined pressure, the piston 43 of the control valve 23 is pushed down and the input port 23b And the output port 23d is closed. As a result, the air master 1
Since the air passage 33 from 6 to the exhaust valve 22 is shut off,
The operation of the service brake (main brake) 15 is reliably ensured.

The control of the exhaust valve 22 is determined by the open / close operation.
Preload P which is the breaking reference_ThreePrimary air pressure P instead of₁And differential pressure
Set pressure P of valve 13₀Difference (P₁−P₀) And (P_Two
> P ₁−P₀) Or (P_Two≤P₁−P₀)
No, secondary air pressure P_TwoSet pressure P₀Lower to below, auxiliary
Slightly activates service brake in conjunction with bouquet 10
You may make it do.

In the above embodiment, a 4-port 2-position electromagnetic directional control valve is used as the bypass valve 20. However, the present invention is not limited to this, and the electromagnetic valve merely opens and closes the bypass passage as shown in FIG. Of course, may be used. Further, instead of the 4-port control valve 23 shown in FIG. 4, a 3-port sequence valve may be used.

[0032]

As described above, according to the air brake device of the present invention, since the control valve is provided between the passage connecting the input side of the air master and the exhaust valve, the exhaust valve may fail. Then, even if the valve is in the open state although it must be in the closed state, when the air pressure on the outlet side of the brake valve becomes higher than a predetermined pressure, the control valve receives the supply of the air pressure, Since the air master operates by shutting off the flow of air pressure from the inlet side of the air master to the exhaust valve, the air pressure to be supplied to the air master is prevented from flowing out to the exhaust valve, and the operation of the service brake is securely ensured. There is an effect that the performance can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an outline of a braking energy regeneration system.

FIG. 2 is a configuration diagram illustrating an air brake device of a vehicle equipped with the braking energy regeneration system of FIG. 1;

FIG. 3 is a configuration diagram showing one embodiment of an air brake device according to the present invention.

FIG. 4 is a sectional view of a control valve.

FIG. 5 is a graph showing an opening and closing operation of a control valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Axle 2 Gear box 3 Hydraulic pump / motor 4 Hydraulic oil tank 5 Switching valve 6 Accumulator 7 Brake pedal 8 Accelerator 9 Control unit 10 Braking energy regeneration system (auxiliary brake) 11 Brake valve 13 Differential pressure valve 14, 21 Pressure sensor 15 Service Brake (main brake) 16 Air master 17 Main brake device 19, 20 Bypass valve (solenoid valve) 22 Exhaust valve 23 Control valve 23a Control port 23b Input port 23c Fourth port 24d Output port 30, 32, 33, 34 Air passage 31 Bypass Passage 40 First cylinder hole 41 Second cylinder hole 42 Third cylinder hole 43 Piston 50 Valve element

Claims (1)

(57) [Claims] An auxiliary brake is provided in addition to a service brake operated by a brake pedal. A differential pressure valve is provided between a brake valve operated by the brake pedal and an air master of the service brake, and the differential pressure valve is bypassed. While providing a bypass valve in the bypass passage to connect an exhaust valve to the input side of the air master,
An air brake device that controls the opening and closing of the bypass valve and the exhaust valve in accordance with the depressed state of a brake pedal to vary the rate of contribution to the control of the auxiliary brake and the service brake. A control valve is provided between the exhaust valve and the control valve. The control valve receives supply of air pressure from an outlet of the brake valve. When the air pressure reaches a predetermined pressure or more, the control valve controls the flow of air from the air master to the exhaust valve. An air brake device characterized by shutting off.