JPH07208217A - Butterfly valve device for exhaust brake - Google Patents

Abstract

PURPOSE:To minimize the amount of exhaust gas leaked outside through a bearing and prevent the fixture of a seal member to a valve stem or the non- smooth rotational movement of the valve stem. CONSTITUTION:A seal member (seal ring) 13 externally mounted adjacent to the inward side end of a bearing member (bush) 6 for a valve stem 4 is always put in close contact with the inner periphery of a fitting hole 1b. When exhaust pressure from a flow passage 2 is applied to the seal member 13, the seal member 13 is closely fixed to the side end of the bearing member 6, so that, a gap between the outer periphery of the bearing member 6 and the inner periphery of the fitting hole 1b is closed.

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 provided in an exhaust gas passage of an automobile engine.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional butterfly valve device, in which a body (1) having a substantially cylindrical cross section is provided with
A valve body (5) whose both ends are held by a pair of left and right valve shafts (3) and (4) orthogonal to the flow path (2) is rotatably accommodated.

Both valve shafts (3) and (4) are bushes (6) loosely fitted in fitting holes (1b) of thick parts (1a) of both side walls of the body (1).
Is rotatably supported by the valve body, and the drive lever (7) bolted to the end of the drive side valve shaft (4) penetrating the body (1) and protruding to the right (5) is opened and closed.

The fitting hole (1b) on the left side is closed by a closing member (8) which is press-fitted into the side end portion thereof. The flow path (2) of the part located inside the bush (6) and inside the fitting hole (1b)
A large diameter portion (4a) having a diameter substantially equal to that of the bush (6) is formed in a portion close to.

In the gap formed between the large diameter portion (4a) and the bush (6), one seal ring (9) is also provided on the outer surface of the bush (6) and the thick portion (1a). Two large and small seal rings (11) and (12) are externally fitted to the outer peripheral surface between the holding plate (10) bolted to the opening end of the seal ring (11) and (12), respectively. The respective seal rings (9), (11) and (12) prevent the exhaust gas in the flow path (2) from leaking to the outside through the bearing portion of the valve shaft (4).

[0006]

The conventional butterfly valve device described above has a problem in its seal structure. That is, as shown in an enlarged view in FIG. 4, the bush (6) takes into account the thermal expansion of itself, the body (1) and the valve shaft (4),
The valve shaft (4) and the fitting hole (1b) are fitted with a slight gap (exaggeratedly shown) (for example, 0.01 mm for the valve shaft and 0.08 mm for the fitting hole). It is common. In such a butterfly valve device, when the inner seal ring (9) is externally fitted to the valve shaft (4) with a gap with respect to the fitting hole (1b), it is fitted from the flow path (2). The high-temperature and high-pressure exhaust gas leaking into the hole (1b) easily enters the larger gap between the bush (6) and the fitting hole (1b), and the outer seal ring (11) (12). It leaks to the outside through a small gap between the two.

In this case, carbon soot contained in the exhaust gas adheres to the outer peripheral surfaces of the fitting hole (1b) and the bush (6), and an oxide film is formed on the mutual contact surfaces. Then, the frictional resistance between the outer peripheral surface of the bush (6) and the inner peripheral surface of the fitting hole (1b) increases, and the rotation of the valve shaft (4) becomes unsmooth.

Further, since the seal ring (9) is brought into close contact with the outer peripheral surface of the valve shaft (4), the seal ring (9) is attached to the valve shaft (4).
If the seal ring (9) sticks to the outer peripheral surface of the valve shaft (4) at a position deviated to the large diameter portion (4a) side of the valve shaft (4), the exhaust pressure from the flow path (2) will be released. ), It cannot move to the right and come into close contact with the bush (6). Therefore, the exhaust gas passing through the gap between the seal ring (9) and the bush (6) is ) And the bush (6).

When the seal ring (9) is further fixed to the valve shaft (4), the seal ring (9) rotates integrally with the valve shaft (4), and the surfaces facing the bush (6) rub against each other. , There is a risk of abrading the contact surfaces of each other. In this case, the gap between the seal ring (9) fitting part becomes larger than necessary,
It is also possible that the amount of exhaust gas leakage increases.

The present invention has been made to solve the above problems, and minimizes the amount of exhaust gas leaking to the outside through the bearing portion, and the seal member is fixed to the valve shaft. An object of the present invention is to provide an exhaust brake butterfly valve device capable of preventing the rotation of a valve shaft from becoming unsmooth.

[0011]

In order to achieve the above object, the present invention provides a valve body housed in a flow path of a body by a valve shaft having one shaft end portion penetrating the body and protruding to the outside. In a butterfly valve device for an exhaust brake, which is supported and rotatably supports both ends of the valve shaft by bearing members loosely fitted in fitting holes communicating with the flow passages formed in both side walls of a body. A ring-shaped seal member is provided at a portion of the valve shaft on the side penetrating the body in the vicinity of the inner side end surface of the bearing member, and the outer peripheral surface of the seal member is closely contacted with the inner peripheral surface of the fitting hole. It is characterized in that a slight gap is formed with respect to the outer peripheral surface of the shaft, and the shaft is externally fitted.

[0012] Preferably, a large diameter portion is formed on a portion of the valve shaft located inward of the bearing member and within the fitting hole, and a large gap is formed between the large diameter portion and the bearing member. It is preferable to provide a seal member.

[0013]

According to the present invention, the seal member externally fitted to a portion of the valve shaft close to the inner side end surface of the bearing member is always in close contact with the inner peripheral surface of the fitting hole and flows into the seal member. When the exhaust pressure from the passage acts, the seal member comes into close contact with the side end surface of the bearing member, thereby closing the gap formed between the outer peripheral surface of the bearing member and the inner peripheral surface of the fitting hole. Therefore, it is possible to prevent the exhaust gas flowing from the flow path into the fitting hole from leaking to the outside through the gap.

Particularly, when a large diameter portion is formed on a portion of the valve shaft located inward of the bearing member and inside the fitting hole, and a seal member is arranged in a gap between the large diameter portion and the bearing member, Since the passage through which the exhaust gas leaks becomes a labyrinth, the amount of exhaust gas that leaks to the outside through the bearing portion becomes smaller.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Since the present invention is an improvement of the above-mentioned conventional butterfly valve device, the same members are denoted by the same reference numerals, detailed description thereof will be omitted, and only the main parts of the device will be enlarged. And illustrated.

In FIG. 1, the large diameter portion (4a) and the bush (6)
A ring-shaped flat washer-shaped seal ring (13) is provided on the valve shaft (4) between the side end surface and the outer peripheral surface of the valve hole (1b).
The outer peripheral surface of the valve shaft (4) is closely fitted to the inner peripheral surface thereof and is fitted on the outer peripheral surface of the valve shaft (4) with a gap (0.01 mm, for example) that does not contact each other. A gap is formed between the seal ring (13) and the large diameter portion (4a) and the bush (6) to the extent that they do not rotate integrally with them. With such a seal structure, when the valve body (5) closes the flow path (2) and the exhaust pressure from the flow path (2) acts on the seal ring (13), the seal ring (13) Is pressed to the right and comes into close contact with the side end surface of the bush (6), closing the opening end of the gap formed between the outer peripheral surface of the bush (6) and the inner peripheral surface of the fitting hole (1b). To do.

As a result, the exhaust gas flowing from the flow path (2) into the fitting hole (15) is discharged to the outside through the gap between the bush (6) and the fitting hole (1b). Prevents the bush
There is no risk that carbon sand or the like will adhere to the outer peripheral surface of (6) or the fitting hole (1b) and the rotation of the valve shaft (5) will not be smooth.

Further, since the seal ring (13) is fitted onto the valve shaft (4) with a gap, the seal ring (13) is fitted.
Does not stick to the valve stem (4). As a result, the seal ring (13) and the valve shaft (4) rotate integrally, and the opposing surfaces of the seal ring (13) and the bush (6) rub against each other,
It is prevented that these surfaces are worn, and that the wear increases the gap between the fitting portions of the seal ring (13) and increases the amount of leak of exhaust gas.

Further, since the seal ring (13) is arranged in the gap between the large diameter portion (4a) and the bush (6), the passage through which exhaust gas leaks becomes a labyrinth and passes through the bearing portion. The amount of exhaust gas that leaks out to the outside becomes smaller.

In the above embodiment, the seal ring
Exhaust gas that has passed through the gap between (13) and the valve shaft (4)
It is expected that it will penetrate into the gap formed between (6) and the valve shaft (4), but the valve shaft of the seal ring (13) and bush (6)
Since the gap with respect to (4) is extremely small, the amount of exhaust gas leaked outside through these gaps is very small.

The seal ring (13) may be a flat spring washer instead of the flat washer type, as shown in FIG.
When this is mounted, it may be elastically deformed in the diameter reducing direction and inserted into the fitting hole (1b), and the cut abutments at the time of mounting may be brought into close contact with each other.

[0022]

According to the present invention, the following effects can be obtained.

(A) Since the seal member (seal ring) prevents the exhaust gas from entering the gap between the bush and the fitting hole, the amount of the exhaust gas leaked from the bearing portion is greater than in the conventional case. Is halved.

(B) As a result of stopping the invasion of exhaust gas into the gap between the bush and the fitting hole, carbon and the like will not adhere to the bush and the fitting hole, and an oxide film will not be formed. The rotation of the valve shaft is prevented from becoming unsmooth.

(C) Since the seal member does not stick to the valve shaft, sliding wear is prevented from occurring between the seal member and the bush, and as a result, the clearance between the seal member fitting portions becomes large. Thus, it is possible to prevent the leakage amount of exhaust gas from increasing.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional plan view of a main part of a butterfly valve device showing an embodiment of the present invention.

FIG. 2 is another embodiment of the seal ring.

FIG. 3 is a cross-sectional plan view of a conventional butterfly valve device to which the present invention is applied.

FIG. 4 is an enlarged cross-sectional plan view of the bearing portion on the right side in FIG.

[Explanation of symbols]

 (1) Body (1a) Thick part (1b) Fitting hole (2) Flow path (3) (4) Valve shaft (4a) Large diameter part (5) Valve body (6) Bush (bearing member) (7) ) Drive lever (8) Closing member (9) (11) (12) Seal ring (seal member) (10) Holding plate (13) Seal ring (seal member)

Claims (2)

[Claims] 1. A valve body housed in a flow path of a body is supported by a valve shaft having one of shaft end portions penetrating the body and protruding to the outside, and both end portions of the valve shaft are provided on both sides of the body. In a butterfly valve device for an exhaust brake, which is rotatably supported by a bearing member loosely fitted in a fitting hole communicating with the flow passage formed in a wall, among the bearing members in the valve shaft on the side penetrating the body. The ring-shaped seal member is closely fitted to the inner peripheral surface of the fitting hole at a portion close to the side end surface on one side, and a slight gap is formed between the outer peripheral surface of the valve shaft and the outer peripheral surface of the valve shaft. A butterfly valve device for an exhaust brake, which is characterized. 2. A large-diameter portion is formed on a portion of the valve shaft that is located inward of the bearing member and inside the fitting hole, and a seal is formed in a gap formed between the large-diameter portion and the bearing member. The exhaust brake butterfly valve device according to claim 1, further comprising a member.