JPH0921334A - Exhaust brake device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a large braking effect immediately after the operation of an exhaust brake without opening the exhaust valve. A valve body (20) formed in an exhaust pipe (6) and having an elliptical plate shape that rotates around an axis orthogonal to a pipe axis is linked to a single-acting fluid pressure cylinder (9) to open and close the vehicle. In the exhaust brake device for braking the valve body 20, the valve body 20 is centered on the valve shaft 19 when the valve is closed by the valve shaft 19 which is eccentric to the pipe shaft center O of the exhaust pipe 6 by a required dimension. The valve body 20 is supported so that the long side thereof inclines toward the exhaust gas downstream side, and the valve body 20 is provided with the pressure adjusting hole 2
5, the pressure adjusting hole 25 is opened and closed by the reed valve 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust brake device used for braking a moving vehicle.

[0002]

2. Description of the Related Art Exhaust brakes are intended to enhance the braking effect when a so-called engine brake is used. By operating an exhaust shutter provided in an exhaust pipe to block the exhaust passage and increase the internal pressure of an exhaust manifold, The engine acts as a compressor to obtain a braking effect.

FIG. 4 schematically shows a conventional exhaust brake device. (1) is an engine cylinder, (2) is a piston, (3) is an exhaust valve, (4) is an intake valve, and (5) is. Is an exhaust manifold, (6) is an exhaust pipe, (7) is an intake manifold, and (8) is an intake pipe.

The exhaust pipe (6) and the intake pipe (8) are respectively
A butterfly valve type exhaust shutter (11) and an intake shutter (12) which are opened and closed by a first air cylinder (9) and a second air cylinder (10) are provided, and both air cylinders (9) and (10) are provided. The compressed air in the air tank (13) is simultaneously supplied via the solenoid valve (15) and the air pipe (14). (16) is a solenoid valve
It is an accelerator switch for actuating (15).

In the above-mentioned device, an accelerator pedal (not shown) is actuated to operate the accelerator pedal.
When you release your foot from (17), the accelerator switch (16) will close and the solenoid valve (15) will open.
Compressed air is supplied to (9) and (10), and the exhaust shutter (11) and the intake shutter (12) are closed at the same time.

As a result, the internal pressure of the exhaust manifold (5) rises rapidly and the reciprocating motion of the piston (2) is restricted,
A great braking effect is obtained.

[0007]

In such an exhaust brake device, in order to enhance the braking effect, the exhaust shutter (11) is rapidly closed to instantly increase the internal pressure of the exhaust manifold (5). Is desirable. However, when the exhaust shutter (11) is rapidly closed during high-speed operation, the internal pressure of the exhaust manifold (5) rises above the set load of the valve spring (not shown) of the exhaust valve (3), and the valve is closed. Exhaust valve
(3) is forcibly opened, and compressed air flows back to the intake manifold (7) side, making a loud noise, or the exhaust valve (3) abuts the head of the piston (2). , May damage them.

In order to prevent the above problems from occurring, the opening of the exhaust shutter (11) is finely controlled so that the pressure in the exhaust manifold does not exceed the opening pressure of the exhaust valve. There is a need to.

However, in order to do so, it is necessary to provide a sensor for detecting the pressure inside the exhaust manifold, a control means for controlling the actuator for operating the exhaust shutter, and the like, which complicates the control system. Since the number of parts increases, the cost becomes high.

The present invention has been made in view of the above problems, and by changing the shape and support form of the exhaust shutter, a large braking effect can be obtained immediately after the exhaust brake is activated without opening the exhaust valve. It is an object of the present invention to provide an exhaust brake device of the above type.

[0011]

SUMMARY OF THE INVENTION According to the present invention, the above object is to provide a single-acting fluid pressure cylinder with a valve body having an elliptical plate shape which is rotatable about an axis orthogonal to a pipe axis provided in an exhaust pipe. In an exhaust brake device that brakes the vehicle by opening and closing the valve body in a closed manner, the valve body is eccentric to the center of the exhaust pipe laterally by a required dimension. The long side of the valve element centering on the valve shaft is supported so as to incline toward the exhaust downstream side, and a pressure adjusting hole is formed in the valve element so that the pressure adjusting hole is oriented substantially in the plate thickness direction. This is solved by providing a pressure regulating valve for the valve so that it can be opened when the pressure in the exhaust manifold reaches a predetermined upper limit pressure.

[0012]

When the exhaust brake is actuated, the valve cylinder closes the flow path of the exhaust pipe by the fluid pressure cylinder to increase the internal pressure of the exhaust manifold, so that a large braking effect can be obtained as in the conventional case.

When the pressure in the exhaust manifold suddenly rises, the valve element in which the valve shaft is eccentric to the side of the pipe axis center is
It is forcibly opened slightly against the pressing force of the fluid pressure cylinder, and the pressure regulating valve is opened to open the pressure adjusting hole. As a result, the pressure inside the exhaust manifold is suddenly reduced,
The exhaust valve is prevented from being forced open.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. It should be noted that the same members as those in the above-described conventional example are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIGS. 1 and 2, in a cylindrical valve box (18) connected to the exhaust pipe (6) at a position close to the exhaust manifold (5), a valve shaft (19 2) is a butterfly-type valve body (20) in the form of an elliptical plate fixed to FIG.
The valve is housed so as to be rotatable between a valve closed position indicated by a solid line and a valve opened position indicated by an imaginary line.

The valve shaft (19) is supported on the peripheral wall of the valve box (18) by eccentricizing the center of rotation (P) of the valve shaft (P) laterally (upward in FIG. 2) from the pipe shaft center (O). ing. This allows the valve body
In (20), the length of the lower half around the valve shaft (19) is longer than the upper half by the required dimension, and when the valve is closed, the long side inclines toward the exhaust downstream side, The entire valve body (20) is inclined forward toward the exhaust gas upstream side.

A drive arm (21) is fixed to the outer end of the valve shaft (19) protruding from the valve box (18), and a long hole (22) is formed at its free end.
Are drilled. The long hole (22) has a first air cylinder.
A connector (23) fixed to the tip of the piston rod (9a) in (9) is pin-pivoted.

The first air cylinder (9) has an air pipe (14).
And an electromagnetic valve (15), and is connected to a constant pressure air tank (24) whose internal pressure is maintained at a predetermined constant pressure.

A pressure adjusting hole (25) is formed in the lower half portion of the valve body (20) so as to extend substantially in the plate thickness direction. The pressure adjusting hole (25)
Is always closed by a reed valve (pressure regulating valve) (26) attached to the exhaust gas downstream side surface of the valve body (20).

The reed valve (26) is opened when the pressure in the exhaust manifold (5) reaches a pressure slightly lower than the set load of the valve spring of the exhaust valve (3), and the pressure adjusting hole (25) is opened. The spring force is set so that it opens.

In the above embodiment, when the foot is released from the accelerator pedal (17) to operate the exhaust brake, as shown in FIG.
As shown in FIG. 2 and FIG. 2, the solenoid valve (15) is operated by the accelerator switch (16), and the first and second air cylinders (9) are
Compressed air is simultaneously supplied to (10), the intake shutter (12) is closed to a predetermined opening, and the valve body (20) is closed to the fully closed position.

As a result, the internal pressure of the exhaust manifold (5) suddenly rises and a braking effect is obtained.

When the vehicle is operating at high speed, the valve body (20) is suddenly closed, and the internal pressure of the exhaust manifold (5) is a predetermined upper limit pressure, that is, a set of a valve spring (not shown) of the exhaust valve (3). When the load is increased significantly beyond the load, the reed valve (26) opens to open the pressure adjusting hole (25) as shown in FIG.
The valve body (20) has a rotation axis (P) of its valve shaft (19) at the exhaust pipe (6).
Since it is eccentric with respect to the center (O) of the valve, the rotational moment acting on the elongated lower half valve body (20) becomes large, and the piston rod of the first air cylinder (9) ( It opens slightly against the pressing force of 9a).

As a result, the pressure in the exhaust manifold (5) is sharply reduced, and the exhaust valve (3) is prevented from being forcibly opened. When the pressure in the exhaust manifold (5) is reduced to a predetermined pressure, the valve body (20) is fully closed again, and then the pressure in the exhaust manifold (5) approaches the valve opening pressure of the exhaust valve (3). When it reaches the exhaust manifold, only the reed valve (26) repeats opening and closing as shown in FIG.
The pressure in (5) is slightly lower than the opening pressure of the exhaust valve (3),
Finely adjusted so that the pressure is maintained at a substantially constant level.

The opening degree and timing of the valve body (20) at this time are appropriately determined by the eccentric amount of the valve shaft (19), the length of the drive arm (21), the pressure in the constant pressure air tank (24) and the like. It can be adjusted arbitrarily by setting to.

As described above, when the reed valve (26) is provided on the valve body (20) to open and close the pressure adjusting hole (25) having a relatively small opening area, the valve body (20) itself is slightly opened and the exhaust manifold is opened. (5)
Since the pressure fluctuation range near the upper limit pressure can be made smaller than the pressure inside is reduced, the efficiency of the exhaust brake is improved.

Further, during low speed operation in which the pressure in the exhaust manifold (5) rises relatively slowly, the pressure is sufficiently reduced by opening / closing only the reed valve (26), so the valve body (20) is opened to greatly reduce the pressure. do not have to.

[0028]

According to the present invention, even if the valve body is suddenly closed and the pressure in the exhaust manifold is rapidly increased, the valve body and the pressure regulating valve are automatically slightly opened at a predetermined pressure. Since the pressure is adjusted, a large braking effect can be obtained immediately after the exhaust brake is activated without opening the exhaust valve. Further, since the pressure adjusting valve opens and closes the pressure adjusting hole, the pressure inside the exhaust manifold can be finely adjusted, so that the pressure fluctuation range becomes small and the exhaust brake becomes more effective.

[Brief description of drawings]

FIG. 1 is a schematic front view showing one embodiment of the present invention.

FIG. 2 is a vertical sectional front view showing the details of the valve body support portion.

FIG. 3 is a vertical sectional front view showing a state in which the valve element and the reed valve are opened when the exhaust brake is activated.

FIG. 4 is a vertical sectional front view showing a state in which only the reed valve is opened.

FIG. 5 is a schematic front view of a conventional exhaust brake device.

[Explanation of symbols]

 (1) Cylinder (2) Piston (3) Exhaust valve (4) Intake valve (5) Exhaust manifold (6) Exhaust pipe (7) Intake manifold (8) Intake pipe (9) First air cylinder (9a) Piston rod (10) Second air cylinder (11) Exhaust shutter (12) Intake shutter (13) Air tank (14) Air pipe (15) Solenoid valve (16) Accelerator switch (17) Accelerator pedal (18) Valve box (19) Valve shaft (20) Valve body (21) Drive arm (22) Long hole (23) Connecting tool (24) Constant pressure air tank (25) Pressure adjusting hole (26) Reed valve (pressure regulating valve)

Claims (1)

[Claims] 1. A vehicle is braked by opening and closing an elliptical plate-shaped valve body, which is provided in an exhaust pipe and rotates about an axis orthogonal to a pipe axis, in association with a single-acting fluid pressure cylinder. In the exhaust brake device configured as described above, the valve body is eccentrically sized laterally with respect to the center axis of the exhaust pipe so that the long side of the valve body centered on the valve shaft is exhausted when the valve is closed. While supporting to incline toward the downstream side,
A pressure adjusting hole is formed in the valve body so as to extend substantially in the plate thickness direction, and a pressure adjusting valve for opening and closing the pressure adjusting hole can be opened when the pressure in the exhaust manifold reaches a predetermined upper limit pressure. An exhaust brake device characterized by being provided on the valve body.