JPH08312794A - Exhaust brake butterfly valve device - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to prevent the bearing from being exposed to high-temperature exhaust gas to cause seizure or the like between the fitting hole and the rotating shaft, and to improve the sealing property of the seal ring. [Structure] A bearing 9 is loosely fitted in a fitting hole 5 provided in the valve holder 3 so as to communicate with the pipe line 4 through which exhaust gas flows and to be orthogonal to the pipe line 4, and the pipe line 4 Valve body 6 housed inside
In the exhaust brake butterfly valve device in which the rotary shaft 7 is rotatably supported by the bearing 9, a flat plate ring-shaped seal member 16 is provided inward of the bearing 9 on the rotary shaft 7. The outer peripheral surface is the fitting hole 5
The outer peripheral surface of the bearing 9 is closely fitted to the inner peripheral surface of the bearing 9 and is externally fitted so as to come into contact with the side surface of the bearing 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust brake butterfly valve device for controlling a braking force by opening and closing an exhaust passage of an automobile engine, and more particularly to a rotary shaft for rotating a valve body. Related to the support structure.

[0002]

2. Description of the Related Art FIGS. 4 and 5 show a conventional butterfly valve device, which includes an exhaust manifold (1) and an exhaust pipe.
It is provided between (2). In the butterfly valve device, a fitting hole (5) orthogonal to the conduit (4) is coaxially provided in the opposing tube wall (3a) of the valve holder (3) having a substantially cylindrical cross section. . The elliptical plate-shaped valve body (6) housed in the pipe line (4) has a pair of left and right rotating shafts (7) and (8) press-fitted on both sides thereof, with both fitting holes (5). Bearings loosely fitted inside (9)
It is rotatably supported by the valve holder (3).

The valve body (6) operates the handle (10) which engages with the one rotating shaft (7) penetrating the valve holding body (3) and protruding leftward. As a result, the valve can be rotated between the valve open position shown by the solid line in FIG. 5 and the valve close position shown by the two-dot chain line.

The bearing (9) is loosely fitted to a portion of the rotary shafts (7) and (8) located in the fitting hole (5) and close to the pipe line (4). On the rotary shafts (7) and (8) outside the bearing (9), two large and small flat plate ring-shaped stainless steel seal rings (12) and (13) are alternately fitted to each other to form a large diameter. The seal ring (12) is in contact with the inner surface of the fitting hole (5), and the seal ring (13) with a small diameter is in contact with the outer peripheral surface of the rotating shaft (7) (see FIG. 6). At the opening end face of the fitting hole (5), the through hole (1
The cover plate (14) having 4a) and the closing plate (15) are fixed to each other to prevent the seal rings (12) (13) and the bearing (9) from coming off. As shown in FIG. 7, each of the seal rings (12) and (13) has a shape in which a part in the circumferential direction is cut off.

In the above butterfly valve device, by arranging large and small seal rings (12) and (13) alternately,
A labyrinth is formed between the two to prevent the exhaust gas flowing in the pipe (4) from leaking to the outside through the penetrating portion of the rotary shaft (7) in the valve holder (3). .

[0006]

In the conventional butterfly valve device described above, the bearing (9) is located closer to the valve body (6) than the respective seal rings (12) and (13), that is, the pipe line (4). Since they are arranged facing each other, they are easily exposed to the high temperature exhaust gas flowing in the pipe (4) to be heated, and are easily affected by the exhaust gas flowing into the fitting hole (5). As a result, an oxide film will be formed on the surface of the bearing (9), carbon or soot will adhere, and a large thermal expansion will occur.
The rotary shaft may be seized between the inner surface of the fitting hole (5) and the rotary shafts (7) and (8), or the frictional resistance may increase.
(7) There is a problem that the rotation of (8) becomes unsmooth.

Further, since the seal rings (12) and (13) are partly cut off in the circumferential direction, exhaust gas easily leaks from the part and enters the fitting hole (5). Further, when exposed to high-temperature exhaust gas, the elastic force is lost due to sagging, and the sealing property may be deteriorated. further,
If the seal rings (12) and (13) are made of the same material, when they rotate together with the rotating shafts (7) and (8), their sliding contact surfaces cause cohesive wear, resulting in sealability. There is also a problem that is damaged.

The present invention has been made in view of the above problems of the prior art. The bearing is exposed to high temperature exhaust gas, and seizure between the fitting hole and the rotating shaft may occur. It is an object of the present invention to provide a butterfly valve device for an exhaust brake, which is capable of preventing the occurrence thereof and improving the sealing performance of a sealing member.

[0009]

According to the present invention, the above problems can be solved as follows. (1) A valve body in which a bearing is loosely fitted in a fitting hole provided in a valve holding body so as to communicate with a pipeline through which exhaust gas flows and to be orthogonal to the pipeline, and the valve body is accommodated in the pipeline. In a butterfly valve device for an exhaust brake, wherein the rotary shaft of the rotary shaft is rotatably supported by the bearing, a flat plate ring-shaped seal member is fitted on the outer peripheral surface of the rotary shaft inward of the bearing. The outer peripheral surface is closely fitted to the inner peripheral surface of the dowel hole and is externally fitted so as to come into contact with the side surface of the bearing.

(2) In the above item (1), a flat plate ring-shaped second seal member, which is in close contact with the outer peripheral surface of the rotary shaft, is provided on the rotary shaft between the bearing and the seal member, and the opposing surfaces of the seal members are opposed to each other. They are fitted so that they can contact each other.

(3) In the above item (1) or (2), a salt bath nitriding treatment is applied to at least one surface of each seal member.

[0012]

The exhaust gas which is about to flow into the fitting hole is sealed by fitting the flat plate ring-shaped sealing member, which is in close contact with the inner peripheral surface of the fitting hole, onto the rotary shaft inward of the bearing. Since it is blocked by, the amount reaching the bearing is small,
It also prevents the bearings from being directly exposed to hot exhaust gases.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. It should be noted that the same members as those of the conventional example are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows a first embodiment of the present invention, in which a bearing portion on the rotary shaft (7) side which penetrates the valve holder (3) is shown in an enlarged manner. The other bearing has the same structure except that the rotary shaft does not pass through the valve holder (3), and is not shown.

A seal ring having a large diameter is arranged in order from the valve body (6) side in a portion located in the fitting hole (5) on the outer peripheral surface of the rotating shaft (7) formed of heat resistant steel (for example, SUH36). (16),
The bearing (9), the large-diameter seal ring (18), the small-diameter seal ring (19), and the seal cap (20) are externally fitted.

Each of the seal rings (16), (18) and (19) is made of stainless steel (for example, SUS304) and formed into a flat plate ring shape shown in FIG. The large-diameter seal rings (16) and (18) are fitted onto the fitting hole (5) with a small gap (for example, 0.01 mm), and the small-diameter seal rings (19) also rotate. axis
It is fitted with a slight gap (0.01 mm, for example) to (7).

The bearing (9) has a rotating shaft in consideration of its thermal expansion.
It is fitted with a slight gap between (7) and the fitting hole (5).

Large and small seal rings (1
8) Salt bath nitriding on either or both surfaces of (19)
(Tuffride) is applied to improve the wear resistance of the contact surface.

The seal cap (20) is press-fitted into the fitting hole (5) with a slight gap formed between the seal cap (20) and the rotary shaft (7), and each seal ring (16) (18) (19) or The bearing (9) is adapted to be held in place.

When the valve body (6) is closed and the pressure of the exhaust gas in the exhaust pipe rises, the gas pressure causes the respective seal rings to rise.
(16) (18) (19) and the bearing (9) are pressed toward the lid plate (14), so that the side surfaces of each of these members and the outermost small-diameter seal ring (19) and seal cap The sides of (20) come into close contact with each other.

On the other hand, the outer peripheral surfaces of the large-diameter seal rings 16 and 18 are the inner peripheral surfaces of the fitting holes 5 and the small-diameter seal rings.
Since the inner peripheral surface of (19) is in close contact with the outer peripheral surface of the rotary shaft (7), the amount of exhaust gas flowing into the fitting hole (5) to the outside is minimized. Can be suppressed. Since the bearing (9) is placed outside the seal ring (16) to prevent it from being directly exposed to exhaust gas, its outer peripheral surface oxidizes, carbon etc. adhere, and a large thermal expansion occurs. Will not cause. As a result, the bearing (9) does not seize in the fitting hole (5) or the rotary shaft (7) and the frictional resistance does not increase, and the rotary shaft (7) can always be smoothly rotated.

Further, since each of the seal rings (16), (18) and (19) is closed in a ring shape, as in the conventional case, the exhaust gas is exposed to high temperature exhaust gas to cause fatigue or exhaust gas. There is no leakage. In addition, large and small seal rings (1
8) Since one or both surfaces of (19) are subjected to salt bath nitriding treatment, there is no risk of causing cohesive wear even if they are made of the same material.

Next, a second embodiment of the present invention will be described with reference to FIG. The same members as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In the second embodiment, between the large-diameter seal ring (16) and the bearing (9) similar to the first embodiment described above, a small-diameter seal ring (21) that is in close contact with the rotating shaft (7) is provided. ) Is additionally provided, and only the small-diameter seal ring (19) is provided outside the bearing (9). Also at this time, the large and small seal rings (1
6) It is preferable to subject one or both surfaces of (21) to salt bath nitriding treatment. The positions of the large-diameter seal ring (16) and the small-diameter seal ring (21) may be reversed.

According to the second embodiment, the bearing (9) is
Since it is located outside the two large and small seal rings (16) and (21), it is unlikely to be affected by heat, and both seal rings
(16) Since the sealing performance of (21) is improved, the amount of exhaust gas flowing into the bearing (9) side is extremely small. as a result,
The effect of preventing seizure between the rotary shaft (7) and the fitting hole (5) is enhanced, and the rotary shaft can be rotated more smoothly.

In each of the above embodiments, the rotary shaft (7)
The salt bath nitriding treatment may also be applied to the surface of the above, and by doing so, the wear resistance of the contact surface with each seal ring or bearing can be improved.

[0027]

According to the present invention, the following effects can be obtained. (a) It is possible to prevent an oxide film from being formed on the contact surface between the bearing and the rotary shaft or the fitting hole, or to prevent carbon or the like from adhering to the rotary shaft. Instead, it can always be rotated smoothly. Further, since the seal member is closed in the form of a ring, it is prevented that the seal member is exposed to high temperature exhaust gas to cause fatigue and the exhaust gas leaks out.

(B) According to the second aspect of the invention, since the thermal effect of the bearing is small and the sealing performance is improved, the effect of preventing seizure between the bearing and the rotary shaft and the fitting hole is enhanced. The rotary shaft can be rotated more smoothly.

(C) According to the third aspect of the invention, even if both seal members are made of the same material, adhesive wear does not occur on their contact surfaces.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional plan view of a bearing portion of a butterfly valve device according to a first embodiment of the present invention.

FIG. 2 is likewise an enlarged perspective view of the seal ring.

FIG. 3 is likewise an enlarged cross-sectional plan view of the bearing portion of the second embodiment.

FIG. 4 is a cross-sectional plan view of a conventional butterfly valve device.

FIG. 5 is a vertical sectional side view of the same.

FIG. 6 is likewise an enlarged cross-sectional plan view of the bearing portion.

FIG. 7 is an enlarged perspective view of the seal ring.

[Explanation of symbols]

 (1) Exhaust manifold (2) Exhaust pipe (3) Valve holder (4) Pipe line (5) Fitting hole (6) Valve body (7) (8) Rotating shaft (9) Bearing (10) Handle (14a ) Through hole (15) Closure plate (16) Large-diameter seal ring (seal member) (18) Large-diameter seal ring (19) Small-diameter seal ring (21) Seal cap (22) Small-diameter seal ring (second Seal member)

Claims (3)

[Claims] 1. A bearing is loosely fitted in a fitting hole provided in a valve holding body so as to communicate with a pipeline through which exhaust gas flows and to be orthogonal to the pipeline, and the bearing is housed in the pipeline. An exhaust brake butterfly valve device, wherein a rotary shaft of a valve element is rotatably supported by the bearing, wherein a flat plate ring-shaped seal member is provided on an inner peripheral surface of the rotary shaft inwardly of the bearing. A butterfly valve device for an exhaust brake, characterized in that the valve is closely fitted to the inner peripheral surface of the fitting hole and is externally fitted so as to come into contact with the side surface of the bearing. 2. A flat plate ring-shaped second seal member, which is in close contact with the outer peripheral surface of the rotary shaft, is provided on the rotary shaft between the bearing and the seal member so that the facing surfaces of both seal members can contact each other. The exhaust valve butterfly valve device according to claim 1, wherein the butterfly valve device is externally fitted. 3. The butterfly valve device for an exhaust brake according to claim 1, wherein at least one surface of each seal member is subjected to a salt bath nitriding treatment.