JPH10153133A - Exhaust brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an abnormal rise of exhaust pressure at the operation time of an exhaust brake with certainty, and secure sufficient braking force under a low speed rotation of an engine. SOLUTION: In this type of exhaust brake device, a brake valve body 12 can be rotated in normal and reverse directions. A piston 14 slid inside an air cylinder 13 as an actuator is located at an intermediate position in a stroke when the brake valve body 12 is fully opened. An exhaust center type three position electromagnetic changeover valve 15 is arranged for switching the rotational direction of the brake valve body 12 from the fully opened state according to an engine speed. A controller 16 is arranged for controlling the changeover valve 15. Clearances S1 between an inner surface 20 of an exhaust flow passage and the brake valve body 12 when the brake valve body 12 is normally rotated and closed, and S2 between an inner surface 20 of the exhaust flow passage and the brake valve body 12 when the brake valve body 12 is conversely rotated and closed are differentiated from each other.

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 in which a brake valve is disposed in an exhaust passage of exhaust gas discharged from an engine of a vehicle or the like, and the brake valve is operated by an actuator. .

[0002]

2. Description of the Related Art FIG. 3 is a schematic diagram showing a main part of a conventional exhaust brake device. In this exhaust brake device, an exhaust brake valve 1 is provided in the middle of an exhaust pipe of an engine (not shown), a brake valve body 3 is attached to a valve shaft 2 of the exhaust brake valve 1, and an exhaust cylinder (not shown) for an actuator is provided. The flow and cutoff of the compressed air from the tank are performed by exciting and demagnetizing the solenoid valve, whereby the rod 5 of the air cylinder 4 is moved in and out, and the clevis 6 connected to the tip of the rod 5 and the outer end of the valve shaft 2 are connected. Installed lever 7
The brake valve element 3 is opened and closed via.

The air cylinder 4 has two stopper bolts 8 and 9 projecting obliquely so as to restrict the rotation range of the lever 7. When the lever 7 comes into contact with the stopper bolts 8 and 9, The brake valve element 3 is set to the open state and the closed state, respectively. In the exhaust brake device, the exhaust brake operates when the brake valve element 3 is in the closed state.

In order to prevent the exhaust valve of the engine from being damaged when the exhaust pressure between the exhaust valve of the engine and the exhaust brake valve 1 is excessively increased when the brake valve element 3 is closed, the brake valve element is used. A gap between the valve 3 and the inner surface of the exhaust passage is provided as a valve gap S. In this case, in order to change the valve gap S, adjustment was performed only with the stopper bolt 9 on the closed side.

[0005]

In the case of such a conventional exhaust brake valve 1, since the valve gap S is adjusted only by the stopper bolt 9 on the closing side, only one set value is set for the valve gap S. Can not. If the valve gap S is too large, the braking force is insufficient, and if it is too small, an excessive load is applied to the engine, which has a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional drawbacks, and has as its object to make it possible to take two set values of a valve clearance so that abnormal exhaust pressure during operation of an exhaust brake can be obtained. Exhaust brake that can reliably prevent a rise in exhaust pressure, ensure a sufficient amount of braking force when the engine is running at low speed, and increase the amount of exhaust leak at high speed rotation to prevent an increase in exhaust pressure It is to provide a device.

[0007]

According to the present invention, a brake valve is disposed in an exhaust passage of exhaust gas discharged from an engine, and the brake valve is operated by an actuator. In the exhaust brake device, the brake valve body is rotatable in both forward and reverse directions, and the brake valve body is rotated in the forward direction to close the valve, and the brake valve body is rotated in the reverse direction to close the valve. The gap between the inner surface of the exhaust passage and the brake valve body can be set to different sizes at different times.

[0008]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an exhaust brake device according to an embodiment of the present invention.

In this exhaust brake device, a brake valve body 12 of an exhaust brake valve 11 is disposed in an exhaust passage of exhaust gas discharged through an exhaust valve of an engine, and the brake valve body 12 can rotate in both forward and reverse directions. The piston 14 that slides in the air cylinder 13 as an actuator is located at an intermediate position of the stroke when the brake valve body 12 is fully opened, and changes the rotation direction from the fully opened state of the brake valve body 12 according to the engine speed. Switching valve 15 for switching between forward and reverse
And a controller 16 for controlling the switching valve 15.

The exhaust brake device has an exhaust brake valve 11 and an air cylinder 13 mounted on a common plate 17, so that when the brake valve body 12 is rotated in the forward direction to close the valve, the brake valve body 12 is closed. The gap between the inner surface 20 of the exhaust passage and the brake valve body 12 can be set to different sizes between when the valve is rotated in the reverse direction and the valve is closed.

The exhaust brake valve 11 is provided with a rotatable valve shaft 22 in a valve box 21 forming a part of an exhaust flow passage, and a butterfly type brake valve body 12 is mounted on the valve shaft 22. , A lever 23 attached to the outer end of the valve shaft 22 is disposed substantially parallel to the brake valve body 12,
A link 24 is rotatably pin-joined to the distal end of 3.

The exhaust brake valve 11 is provided with mounting pieces 26 and 27 protruding from two sides of the valve box 21 in the same manner as in the prior art.
The stopper bolts 28, 29 are screwed obliquely to each other, and can be fixed with lock nuts 30, 31, and the stopper bolts 28, 29 projecting from the corresponding mounting pieces 26, 27 respectively.
By adjusting the protrusion dimensions of the heads 28a, 29a of the 29, the position where the lever 23 comes into contact and stops is adjusted.

In this embodiment, when fully open, the brake valve body 12 is substantially parallel to the axis of the valve box 21, and from this state, the lever 23 rotates counterclockwise in FIG. Valve gap S when closed
_1, the lever 23 is set to be narrower than the valve clearance S ₂ when in the closed state rotates clockwise, upon actuation of the exhaust brake, becomes closed, the operation of the exhaust brake When released, it becomes fully open.

The air cylinder 13 includes a cylindrical cylinder body 33 and a piston 14 sliding within the cylinder body 33.
And both ends of the cylinder body 33 are respectively
4, 35, and through the portion of the cylinder body 33 near the lids 34, 35, the supply / discharge port 3
6, 3 provided with a rod 3 connected to the piston 14.
8 penetrates one lid 35, and the tip of the rod 38 is pin-joined to the end of the link 24. An O-ring 39 is arranged on the inner periphery of the through hole 35 a of the lid 35.

The piston 14 has a piston ring 4
0 are fitted, and two working pressure chambers 4
1 and 42, and are urged from both directions by compression springs 43 and 44 in the working pressure chambers 41 and 42, respectively.
When the compressed air in the working pressure chambers 41 and 42 is discharged, the urging forces from both directions are balanced and the cylinder is stopped at an intermediate position in the cylinder body 33.

Then, the air cylinder 13 is
4 is stopped at the intermediate position, the brake valve element 12
Is fully opened, and when compressed air is supplied to one working pressure chamber 41 and exhausted from the other working pressure chamber 42 and released to atmospheric pressure, the protruding length of the rod 38 becomes longer and the lever 23 is moved clockwise. When the compressed air is supplied from one working pressure chamber 41 to the other working pressure chamber 42 and the compressed air is supplied to the other working pressure chamber 41, the length of the rod 38 protruding becomes short, and the lever 23 is rotated counterclockwise.

The switching valve 15 is an exhaust center type three-position solenoid valve having an exhaust port 50 and two supply / discharge ports 51, 52, each of which corresponds to the air cylinder 13. The supply and discharge ports 36 and 37 are connected by respective pipes 53 and 54, and the controller 16 is connected to terminals 55 and 56 of the electromagnetic coils at both ends by respective signal lines 57 and 58.

In the position A where the electromagnetic coil at one end is excited, the switching valve 15 is evacuated from one working pressure chamber 41 and simultaneously supplied with compressed air from an air source 59 to the other working pressure chamber 42. At a position B where the electromagnetic coil on the other end is excited, compressed air is supplied from one air source 59 to one working pressure chamber 41 and exhausted from the other working pressure chamber 42 at the same time. 4
1, 42 are released from the exhaust port 50 to atmospheric pressure.

The controller 16 includes a clutch switch C
L, an accelerator switch AC and an exhaust brake switch E are connected in series, and an engine speed N is input. When operating the exhaust brake, the controller 16 controls the engine speed N (rp.
m. ) Is 1200 or less, the switching valve 15 is set to the position A, and when the engine speed N exceeds 1200, the switching valve 15 is set to the position B.

The operation of the exhaust brake device according to the above embodiment will be described. When the exhaust brake device is not operated, both the exhaust brake switch E and both electromagnetic coils of the switching valve 15 are off, the switching valve 15 is at the center position C, and both the operating pressure chambers 41 and 42 are Open to atmospheric pressure, piston 14 is in an intermediate position. As a result, the brake valve element 12 is in a fully open state.

When operating the exhaust brake device,
When the driver manually turns on the exhaust brake switch E while the clutch switch CL and the accelerator switch AC are on, the signal from the controller 16 according to the engine speed N causes the engine speed N
When (rpm) is 1200 or less, the switching valve 15 is set to the position A. Thereby, one working pressure chamber 41
Is released to the atmospheric pressure, compressed air is supplied to the other working pressure chamber 42, the piston 14 slides in a direction to reduce the one working pressure chamber 41, and the rod 38 enters to push the brake valve body 12 back. rotate clockwise to close the brake valve 12 at the narrower state in which the valve clearance S _1.

When operating the exhaust brake device, the engine speed N is set to 1200 rpm. p. m. Is exceeded, the switching valve 15 is set to the position B by the signal from the controller 16. As a result, compressed air is supplied to one working pressure chamber 41 and exhausted from the other working pressure chamber 42, the piston 14 slides in a direction to expand the one working pressure chamber 41, the rod 38 projects and the brake valve body 12
The rotated clockwise to close the brake valve 12 at the wider state in which the valve clearance S _2.

FIG. 2 shows an engine speed N (rp.p.) during operation of the exhaust brake valve device according to the above embodiment.
m. 4) is a graph showing the relationship between the pressure P and the exhaust pressure P (kg / cm ² ). According to this, the engine speed N is 120
When the engine speed N exceeds 1200, it becomes a constant proportional straight line L ₁ , and when the engine speed N exceeds 1200, it becomes a gentle slope straight line L _{2 in which the} rate of increase of the exhaust pressure P decreases. Can be reliably prevented, the braking force becomes relatively large when the engine is running at a low speed, and the amount of exhaust gas leakage is increased when the engine is running at a high speed to prevent the exhaust pressure from rising.

According to the above-described embodiment of the present invention, when the exhaust brake valve 11 is in the fully opened state, the piston 14 is balanced by receiving the biasing forces from the compression springs 43 and 44 in opposite directions. Since the run-out can be stopped and the stopper bolts 28 and 29 which are screwed obliquely to the mounting pieces 26 and 27 projecting from the two sides of the valve box 21 are used as in the conventional case, a reliable valve is provided. There is an advantage that the gaps S ₁ and S ₂ can be set.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, a type other than an air cylinder may be used as the actuator, and the operation of the switching valve may be performed based on an exhaust pressure sensor instead of the engine speed.

[0026]

According to the first aspect of the present invention, the brake valve is rotatable in both forward and reverse directions, and the brake valve is rotated in the forward direction to close the valve and the brake valve is reversed. The gap between the inner surface of the exhaust flow passage and the brake valve body can be set to different sizes between when the valve is rotated in the direction of rotation and when the valve is closed. It is possible to reliably prevent an abnormal increase in exhaust pressure during operation of the exhaust brake, secure a sufficient braking force at low engine speeds, This has the effect of increasing the amount of leak and preventing an increase in exhaust pressure. According to the second aspect of the present invention, an air cylinder is used as an actuator, and a piston that slides in the air cylinder is set at an intermediate position of a stroke in a fully opened state of a brake valve body, and the brake valve body is set in accordance with the engine speed. A switching valve for switching the direction of rotation from a fully opened state to a normal or reverse direction;
By providing a controller for controlling the operation of the switching valve, forward and reverse switching of the rotation direction of the brake valve body can be performed smoothly. Further, since the switching valve is an exhaust center type three-position solenoid valve that is in the exhaust state at the center position, the forward and reverse switching of the rotation direction of the brake valve body can be performed more smoothly.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an exhaust brake device according to an embodiment of the present invention.

FIG. 2 is a graph showing a relationship between an engine speed N (rpm) and an exhaust pressure P (kg / cm ² ) when the exhaust brake valve according to the embodiment of the present invention operates. is there.

FIG. 3 is a schematic configuration diagram showing a main part of a conventional exhaust brake device.

[Explanation of symbols]

S ₁ , S ₂ Valve gap 11 Exhaust brake valve 12 Brake valve body 13 Air cylinder (actuator) 14 Piston 15 Switching valve 16 Controller 20 Inner surface of exhaust passage 21 Valve box (forms part of exhaust passage) 22 Valve Shaft 23 Lever 28,29 Stopper bolt 41,42 Working pressure chamber

Claims (3)

[Claims] 1. An exhaust brake device in which a brake valve is disposed in an exhaust passage of exhaust gas discharged from an engine and the brake valve is operated by an actuator, the brake valve is rotatable in both forward and reverse directions. When the brake valve body is rotated in the forward direction to close the valve, and when the brake valve body is rotated in the reverse direction to close the valve, the inner surface of the exhaust passage and the brake valve body are An exhaust brake device characterized in that the size of the gap can be set to different sizes. 2. An air cylinder is used as the actuator, and a piston that slides in the air cylinder is set at an intermediate position of a stroke when the brake valve body is fully opened, and the brake valve body is fully opened according to the engine speed. 2. The exhaust brake device according to claim 1, further comprising a switching valve for switching the rotation direction from a normal state to a reverse direction, and a controller for controlling an operation of the switching valve. 3. The exhaust brake device according to claim 2, wherein the switching valve is an exhaust center type three-position solenoid valve that is in an exhaust state at a center position.