JPH0332759Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to the structure of an exhaust throttle valve installed in an exhaust passage of an engine.

(Prior Art) It is known to provide an exhaust throttle valve in the exhaust passage of an engine and use the back pressure when the exhaust is throttled to operate an exhaust brake or a warm-up device. Japanese Patent Publication No. 50-6915 discloses a device in which a single exhaust throttle valve is installed in the exhaust passage, and the back pressure when the valve is throttled can be used as both a warm-up accelerating device and an exhaust brake device. has been done. This throttle valve has a structure in which a valve body having a cross-sectional shape complementary to the exhaust passage is fixed to a spindle that is pivotally supported on the exhaust passage wall.
The exhaust throttle valve is opened and closed by rotating the valve body. In this case, the spindle is
It is fitted into a cylindrical bush and is supported by the shaft.
Normal lubrication with lubricating oil is impossible for the sliding contact between the inner surface of the bush and the outer surface of the spindle due to the high temperature. Therefore, a certain clearance is provided between the bush and the spindle, and exhaust gas is introduced into this clearance. However, this is now done using carbon components in the exhaust gas.

(Problems to be Solved) The above-mentioned throttle valve lubrication structure is advantageous in that it does not require a special lubrication mechanism, but the clearance between the bush and the spindle is required to obtain the above-mentioned lubrication effect. Because of this, the backlash between the bushing and the spindle inevitably increases, resulting in vibration noise and exhaust gas passing through this clearance to the outside. Leakage and the resulting noise become a problem. Also, such large wobble means that
This results in an adverse effect on the durability of the throttle valve bearing.

(Means for solving the above problems) In view of the above problems, the present invention aims to reduce the clearance between the throttle valve spindle and the bushing to prevent the adverse effects while ensuring the desired lubrication performance. The purpose is

The exhaust throttle valve according to the present invention includes a cylindrical bush inserted into a bearing hole formed in the exhaust passage wall, a spindle rotatably fitted into the bush.
A valve body is fixed to the spindle and arranged in the exhaust passage, and as the spindle rotates, the valve body rotates to open and close the exhaust passage.

The spindle is provided with a through hole, and when the throttle valve is closed, one opening opens to the exhaust passage upstream of the throttle valve, and the other opening opens to the bush and the spindle. It is characterized in that it is configured to open in the downstream part of the clearance between the

(Function) When the throttle valve is closed, exhaust pressure acts on the valve from the upstream side, so it is pressed against the downstream side of the spindle and comes into sliding contact with the inner surface of the bush mainly on the downstream side. According to the present invention, in this state, one of the through holes opens on the upstream side of the exhaust passage.
Exhaust gas is introduced into the through hole from this opening.
At this time, one opening of the through hole is opened downstream of the clearance, and the exhaust gas introduced into the through hole flows out downstream of the clearance, near the pressure contact area between the bush and the spindle. Lubricate.

(Description of Embodiment) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Referring to FIG. 1, an exhaust throttle valve 1 according to the present invention is shown, and the throttle valve 1 has an exhaust passage 2 inside.
It is adapted to be attached to an exhaust pipe 3 in which an exhaust pipe 3 is formed. The throttle valve includes a valve housing 4 constituting a part of the exhaust pipe 3, a cylindrical bush 5 fitted into a bearing hole 4a of the valve housing 4, and the bush 5.
The valve body 7 includes a spindle 6 that is housed so as to rotate while slidingly contacting the exhaust passage 2, and a valve body 7 that is fixed to the spindle 6 and opens and closes the exhaust passage 2 in accordance with the rotation of the spindle 6. A seal ring 6b is inserted between the spindle 6 and the flange portion 8 at a position adjacent to the bush 5 in the axial direction. A plate-like member 10 is fixed to one end of the housing 4 by bolts 9, and the plate-like member 10 has the housing 4 attached to it.
A through hole 10a having a screw is formed at a position aligned with the bearing hole 4a. A bolt 11 is screwed into the through hole 10a, and biases the spindle 6 in the axial direction at the end surface 6a via a leaf spring 12. Further, a casing 14 of an operating unit of the throttle valve 1 is fixed to the other end of the housing 4 by a bolt 13. The spindle 6 also has a through hole 15 that diagonally passes through the spindle 6.
One opening 15a of the through hole 15 opens into the exhaust passage 2, and the other opening 15a opens into the exhaust passage 2.
5b is open to the inner surface of the bush 5. 1st
The illustrated state is when the throttle valve 1 is in an open state, and the front side of the paper is the upstream side of the exhaust passage. Referring also to FIG. 2, when the throttle valve 1 is in the closed state as shown by the imaginary line in FIG. , through hole 1
The opening 15b of No. 5 opens on the downstream side of the inner surface of the bush. In this case, as shown in principle in FIG. 3, a certain clearance 16 is provided between the spindle 6 and the bush 5, and the exhaust gas is introduced into this clearance 16, and the carbon component of the exhaust gas is , the inner surface of the bush 5 and the spindle 6
The sliding contact area with the outer surface of the holder is lubricated. When the throttle valve 1 is closed, the exhaust pressure pushes the valve body 7 downstream, thereby causing the spindle 6
is in sliding contact with the inner surface of the bush 5 on the downstream side.
According to this example, exhaust gas is introduced from the upstream side of the throttle valve into the clearance portion near the sliding contact portion through the through hole 15, and lubricates this portion.

(Effects of the Present Invention) According to the present invention, exhaust gas is introduced through the through hole provided in the spindle, and this makes it possible to sufficiently lubricate the sliding contact between the outer surface of the spindle and the inner surface of the bushing. The clearance between the bush and the spindle can be reduced.
That is, the present invention can eliminate the adverse effects caused by large clearances while ensuring sufficient lubricity.

[Brief explanation of drawings]

FIG. 1 is an overall view of an exhaust throttle valve according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG.
The figure is a schematic diagram showing the principle of the closed state of the throttle valve. 1...throttle valve, 2...intake passage, 3...exhaust pipe,
4...Valve housing, 5...Button, 6...Spindle, 7...Valve body, 15...Through hole.

Claims (1)

[Scope of utility model registration request] A cylindrical bush inserted into a bearing hole formed in an exhaust passage wall, a spindle rotatably fitted into the bush, and a valve body fixed to the spindle and disposed in the exhaust passage. In an engine throttle valve structure in which the valve body rotates in response to rotation of a spindle to open and close an exhaust passage, the spindle is provided with a through hole, and the through hole is configured to: When the throttle valve is closed, one opening opens into the exhaust passage upstream of the throttle valve, and the other opening opens into the downstream part of the clearance between the bush and the spindle. Features the engine's exhaust throttle valve structure.