JP3011604B2 - Structure of bearing hole of exhaust shutter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing hole of an exhaust shutter for rotatably providing a shaft in a bearing hole provided in a shutter housing, mounting a butterfly valve on the shaft, and opening and closing an exhaust passage from an engine. Regarding the structure.

[0002]

2. Description of the Related Art A technique is known in which an exhaust shutter is provided in an exhaust passage of an engine of a vehicle and the shutter is closed to increase a braking force of an engine brake (for example, Japanese Utility Model Application Laid-Open No. Sho 62-43143). .

[0003]

However, in the above technique, the temperature of the butterfly valve rises due to the high-temperature exhaust and expands in the axial direction of the shaft. In addition, there is a problem that the opening and closing operation of the butterfly valve becomes difficult.

Accordingly, it is an object of the present invention to provide a structure of a bearing hole of an exhaust shutter in which a butterfly valve always operates normally.

[0005]

According to the present invention, a bush provided in a shutter housing is provided with a rotatable shaft, a butterfly valve is mounted on the shaft, and an exhaust shutter for opening and closing an exhaust passage from an engine is provided. In the structure of the bearing hole, both ends of the bearing hole provided on the shutter housing on the butterfly valve side are chamfered to a surface width of 1 mm to 3 mm.

[0006]

[0007]

Since the present invention is constructed as described above, even if the butterfly valve extends in the axial direction of the shaft due to thermal expansion, the mounting hole of the bearing for rotatably mounting the shaft of the butterfly valve is provided. Since the end on the butterfly valve side is chamfered, the operation of the butterfly valve does not become uncomfortable.

If the chamfer is 1 mm or less in width, the chamfer is not sufficient, and it is not possible to sufficiently reduce the bitterness of the butterfly valve. If the surface width is 3 mm or more, the gap may be too large, the leakage of exhaust gas may be too large, or the butterfly valve may not operate normally due to a bias. Preferably, the surface width is 2 mm.

[0009]

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

Referring to FIG. 1, a passage 5 through which exhaust gas of an engine passes is provided in a housing 1 of an exhaust shutter. Referring to FIG. 2, a bearing hole 6 orthogonal to the passage 5 is provided with a rotatable shaft. A butterfly valve 3 is fixed to the shaft 2. And
The end of the bearing hole 6 on the butterfly valve 3 side is chamfered over the entire circumference to form a chamfered portion 7 (shown on the right side in FIG. 2).

Reference numeral 4 denotes a lever fixed to one end of the shaft 2 for operating the butterfly valve 3.

Therefore, when the butterfly valve 3 extends in the axial direction of the shaft 2 due to thermal expansion, the edge between the bearing hole 6 of the housing 1 and the inner peripheral surface of the passage 5 is formed without the chamfered portion 7. Interference with the outer peripheral edge of When the chamfered portion 7 is provided, as shown in FIG. 2, it can be smoothly rotated without interfering with the outer peripheral end surface of the butterfly valve 3. And in this case,
If the chamfer is less than C1 (1 mm in width), it is not enough, and it cannot be sufficiently improved that the butterfly valve 3 becomes harsh.
On the other hand, if it is C3 (surface width: 3 mm) or more, the leakage of gas from the chamfered portion 7 is too large.
The valve may not operate normally due to bias.

Therefore, C1 to C3 (surface width 1 mm to 3 m
With the chamfering of m), the butterfly valve operates normally without being troubled, but it is preferable to chamfer to C2 (surface width 2 mm).

[Brief description of the drawings]

FIG. 1 is a front view of a main part of an exhaust shutter showing one embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Shutter housing 2 ... Shaft 3 ... Butterfly valve 4 ... Lever 6 ... Bearing hole 7 ... Chamfered part

Claims (1)

(57) [Claims] 1. A structure of a bearing hole of an exhaust shutter for rotatably providing a shaft to a bush provided in a shutter housing, attaching a butterfly valve to the shaft, and opening and closing an exhaust passage from an engine. A structure of a bearing hole of an exhaust shutter, wherein end portions of the provided bearing holes on both sides of the butterfly valve are chamfered to a surface width of 1 mm to 3 mm.