JPH0227152Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an exhaust brake valve for a vehicle such as a truck or a bus, and more specifically, to an improvement of a slide type exhaust brake valve.

In order to increase the effectiveness of engine braking in a vehicle equipped with a diesel engine, it is effective to install an exhaust brake valve in the exhaust system of the engine. As such exhaust brake valves, the so-called butterfly type and the slide type are well known.

However, in the former butterfly type exhaust brake valve, since the valve is constantly exposed to exhaust gas, the bearing part of the valve tends to become stuck, and it is difficult to maintain a high degree of sealing of the valve. In addition, with the latter type of sliding exhaust brake valve, the valve protrudes from the valve chamber and blocks the exhaust passage only when the exhaust brake is activated, and when the exhaust brake is not activated, the valve is retracted into the valve chamber, so that the valve This has the advantage that the thermal load can be reduced, and since the valve can be brought into surface contact with the valve seat, the degree of sealing of the valve can be increased and the braking force of the exhaust brake can be increased.

However, with a sliding exhaust brake valve,
Carbon and the like attached to the valve tend to peel off due to contact with the housing and accumulate in the valve chamber. In particular, when the valve chamber is formed downward from the exhaust passage, the accumulated carbon is not substantially discharged, which may cause malfunction or malfunction of the valve.

This invention was made in view of the above, and
The high-pressure air discharged from the air cylinder that slides the sliding valve is actively used to forcefully ventilate the valve chamber each time the valve opens and closes, thereby removing carbon, etc. that tend to accumulate inside the valve chamber. The purpose is to prevent malfunction and functional failure of the slide type exhaust brake valve by blowing it out into the exhaust passage.

In order to achieve this object, the present invention forms a valve chamber in a housing interposed in the exhaust passage of the engine, and includes a valve slidably housed in the valve chamber and an air cylinder attached to the outside of the housing. The slide type exhaust brake valve is connected to a piston via a rod so that as the piston slides, the valve moves into and out of the valve chamber into the exhaust passage to open and close the exhaust passage. connecting an air supply/exhaust passage provided in the air cylinder to an air passage leading to the innermost end of the valve chamber and an air supply passage extending from an air supply source;
Moreover, the feature is characterized in that a switching valve is provided which connects the supply/exhaust passage to the air supply passage when air is supplied to the air cylinder, and switches and connects the supply/exhaust passage to the ventilation passage when the air cylinder is exhausted. There is.

Therefore, when the supply/exhaust passage is connected to the air supply passage via the switching valve, air is supplied from the air supply passage to the air cylinder via the supply/exhaust passage, so that the valve does not open from the valve chamber. The protrusion operates to close the exhaust passage. Further, when the supply/exhaust passage is switched and connected to the ventilation passage, the air that has been supplied to the air cylinder is ejected from the supply/exhaust passage through the ventilation passage to the innermost end of the valve chamber. Therefore, in this state, the valve is retracted (retracted) into the valve chamber, contrary to the above-mentioned air supply, but in this retracted state, air is discharged to the exhaust passage through the valve chamber. At the same time, the valves being stored in the valve chamber are cooled down, and at the same time carbon, etc. that have entered the valve chamber are blown away and cleaned.
Valve malfunctions are prevented.

Embodiments of the present invention will be described in detail below with reference to the drawings.

An exhaust passage 6 is formed in a housing 2 interposed in the middle of an exhaust pipe 1 extending from an exhaust manifold of an engine to a muffler, and a valve chamber 4 is formed substantially perpendicular to the passage 3. A valve 5 is slidably accommodated in the valve chamber 4, and the piston 7 of the air cylinder 6 attached to the lower part of the housing 2 and the valve 5 are connected via a rod 8, so that the air cylinder When air is supplied to the piston 6 and the piston 7 is moved upward in the figure against the spring 9, the valve 5 in the valve chamber 4 protrudes into the exhaust passage 3 and closes this passage 3.

On the other hand, the air supply and exhaust passage 1 provided in the air cylinder 6
0 is equipped with a switching valve 11, which connects an air passage 12 to the innermost end (bottom) of the valve chamber 4 and an air supply passage 13 extending from an air supply source via a control valve (not shown). is connected to the supply/exhaust passage 10 via the switching valve 11.

Here, the switching valve 11 is constituted by, for example, a swing valve, and when air is supplied from the air supply path 13 to the air cylinder 6 via the air supply and exhaust path 10 as the control valve opens. This air flow swings as shown by the solid line in the drawing to close the ventilation passage 12, and conversely, when the control valve closes and the air supply passage 13 is opened to the atmosphere, the air supply and exhaust As the air flows from the passage 10 toward the air supply passage 13, the switching valve 11 swings toward the air supply passage 13, as shown by the two-dot chain line in the drawing, so as to switch and connect the supply and exhaust passage 10 to the ventilation passage 12. It's summery. In the figure, 14 is a breathing hole that communicates the back chamber of the piston 7 with the atmosphere, 15 is a small hole provided in the valve 5, and 16 is a small hole provided in the valve 5 to close the small hole 15 when the valve 5 is closed. This is an auxiliary valve that opens a small hole 15 when the valve 5 is opened to reduce the pressure difference between the upstream and downstream sides of the valve 5.

In the above configuration, when the control valve opens and air is supplied to the air supply path 13, the pressure (flow) of this air causes the switching valve 11 to move toward the ventilation path 12 as shown by the solid line in the figure. It is pressed and swung to close the ventilation passage 12 and maintain communication between the air supply passage 13 and the supply/exhaust passage 10. Therefore, the air supplied to the air supply path 13 flows into the air cylinder 6 through the air supply and exhaust path 10, and the pressure of this air pushes up the piston 7 against the spring 9.
When the piston 7 rises in this manner, the valve 5 is pushed into the exhaust passage 3 via the rod 8 and closes this passage 3. Therefore, air cylinder 6
When air is supplied to the exhaust passage 3, the back pressure of the engine increases and the exhaust brake is activated.

Further, when the control valve (not shown) is closed and the air supply passage 13 is opened to the atmosphere, the air supply and exhaust passage 1
Air begins to flow from 0 toward the air supply path 13. Then, due to this air flow, the switching valve 11 is pushed and swung toward the air supply path 13 as shown by the two-dot chain line in the drawing, so that the air supply and exhaust path that was previously connected to the air supply path 13 is 10 is switched and connected to the air passage 12. Therefore, the air in the air cylinder 6 is ejected and supplied from the supply/exhaust passage 10 to the innermost end (bottom) of the valve chamber 4 via the ventilation passage 12. Then, the air ejected into the valve chamber 4 flows out into the exhaust passage 3 together with carbon and the like that tend to accumulate in the chamber 4, so that the inside of the valve chamber 4 is forcibly cleaned. Therefore, carbon and the like separated from the valve 5 are not deposited in the valve chamber 4, and malfunction of the valve 5 can be prevented. Furthermore, since the valve 5 is cooled by the air flowing out into the exhaust passage 3 through the valve chamber 4 as described above, the temperature of the valve 5 can be lowered, and functional deterioration such as poor adhesion due to thermal deformation can be prevented. Ru.

Note that as the air is exhausted from the air cylinder 6, the piston 7 is pushed down by the tension of the spring 9.
Since the valve 5 is pulled back into the valve chamber 4 via the rod 8, the exhaust brake is of course released in synchronization with the exhaust from the air cylinder 6.

In the above embodiment, the switching valve 12 is configured as a swing valve so that the switching operation of the valve 12 is performed using the flow of air in the air supply/exhaust passage 10. The present invention is not limited to this, and the switching valve may be configured with a solenoid valve to function as a control valve. or,
If there is a risk that engine exhaust gas may flow backwards from the valve chamber 4 to the air cylinder 6 through the air passage 12, a check valve may be installed in the air passage 12.
Additionally, it is desirable to install an air filter in the suction hole 14 of the air cylinder 6 to prevent inhalation of dust and the like.

As explained above, according to the present invention, the exhaust air (air) from the air cylinder is ejected and supplied to the innermost end of the valve chamber, and is discharged through the valve chamber to the exhaust passage, thereby forcibly ventilating the valve chamber. Therefore, carbon etc. peeled off from the valve etc. do not accumulate in the valve chamber, and malfunction of the valve can be prevented. In addition, when ventilating (cleaning) the valve chamber as described above, the housing and valve are forcibly cooled, reducing thermal deformation and preventing functional failures such as poor adhesion, which improves the reliability of the slide type exhaust brake valve. The properties and durability can be improved. Furthermore, since the air is discharged into the exhaust passage through the valve chamber as described above, the sound of air discharge can be significantly reduced, and the noise emitted from this type of exhaust brake valve can also be reduced.

[Brief explanation of the drawing]

The figure is a sectional view showing an embodiment of the present invention. 1... Exhaust pipe, 2... Housing, 3... Exhaust passage, 4... Valve chamber, 5... Valve, 6... Air cylinder, 7... Piston, 8... Rod, 9
... Spring, 10 ... Supply and exhaust path, 11 ... Switching valve, 12 ... Ventilation path, 13 ... Air supply path, 14 ...
...breathing hole.

Claims (1)

[Scope of utility model registration request] By forming a valve chamber in a housing interposed in the exhaust passage of the engine, and connecting the valve slidably housed in the valve chamber and the piston of an air cylinder attached to the outside of the housing via a rod, In the slide type exhaust brake valve, the valve is moved in and out of the valve chamber as the piston slides to open and close the exhaust passage, and the supply and exhaust passage provided in the air cylinder is connected to the innermost end of the valve chamber. and an air supply path extending from an air supply source, and connects the air supply and exhaust path to the air supply path when supplying air to the air cylinder, while A slide type exhaust brake valve characterized in that a switching valve is provided for selectively connecting the supply/exhaust passage to the ventilation passage.