JP4899130B2 - Butterfly valve - Google Patents

Description

  The present invention relates to a butterfly valve, and more specifically, a bearing provided in a through hole formed in a housing, a valve shaft rotatably supported by the bearing, and an end of the valve shaft provided from the valve shaft. A valve body holding portion having a large diameter, and a sealing means for sealing between the end portion on the gas passage side of the bearing and the end portion on the bearing side of the valve body holding portion. It is related with the provided butterfly valve.

Conventionally, a housing in which a gas passage through which a gas flows and a through hole formed in a direction intersecting the gas passage is formed, a bearing provided in the through hole, and a shaft rotatably supported by the bearing. A valve shaft, a valve body holding portion provided at an end of the valve shaft on the gas passage side and having a larger diameter than the valve shaft, and connected to the valve body holding portion to open and close the gas passage There is known a butterfly valve comprising: a valve body that seals and a seal ring that is sandwiched between an end portion on the gas passage side of the bearing and an end portion on the bearing side of the valve body holding portion to seal them Yes. (Patent Document 1)
According to the butterfly valve described in Patent Document 1, the valve body, the valve body holding portion, and the valve shaft are integrally biased toward the bearing side by the pressure of the exhaust gas flowing through the gas passage. The seal ring is held between the bearing and the valve body holding portion to prevent the exhaust gas from leaking from the through hole.
JP 2004-353695 A

Here, the valve shaft and the valve body holding portion are manufactured integrally, and the stepped portion formed at the boundary between the valve shaft and the valve body holding portion has an R shape in order to maintain strength and simplify the processing process. A shape may be formed.
In the case where such an R shape is formed, if the seal ring is pinched between the bearing and the valve body holding portion, the inner peripheral surface of the seal ring may be deformed or inclined due to interference with the R shape. As a result, there was a problem that the sealing performance deteriorated.
In view of such a problem, the present invention provides a butterfly valve capable of obtaining high sealing performance when a sealing means is sandwiched between a bearing and a valve body holding portion.

That is, the butterfly valve according to claim 1 includes a housing in which a gas passage through which a gas flows and a through hole formed in a direction intersecting the gas passage is formed, and a bearing provided in the through hole. A valve shaft rotatably supported by the bearing, a valve body holding portion provided at an end of the valve shaft on the gas passage side and having a larger diameter than the valve shaft, and the valve body holding A valve body that is connected to a portion and opens and closes the gas passage, and a sealing means that seals between the end of the bearing on the gas passage side and the end of the valve body holding portion on the bearing side In the butterfly valve with
An R shape is formed in the step portion formed at the boundary between the valve shaft and the valve body holding portion,
At least one first seal ring that abuts the end of the bearing on the gas passage side to seal the corresponding contact portion, and the end of the valve body holding portion on the bearing side contacts the corresponding contact. A second seal ring that seals the part, and abuts the first seal ring and the second seal ring to seal the corresponding contact part,
Also, the inner peripheral surface of the second seal ring and the R shape are prevented from interfering with each other, and the thickness of the second seal ring is set so that the inner peripheral surface of the first seal ring and the R shape do not interfere with each other. It is characterized by its thickness.

  According to the present invention, by providing the second seal ring, the first seal ring interferes with the R shape even when the first and second seal rings are sandwiched between the bearing and the valve body holding portion. Therefore, it is not deformed or tilted, so that high sealing performance can be obtained without providing a step for removing the R shape.

The present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows a butterfly valve 1 used in an exhaust brake device, and the butterfly valve 1 is disposed in the middle of an exhaust pipe (not shown). And by opening and closing the exhaust pipe by this butterfly valve 1, a conventionally known exhaust brake action can be obtained.
The butterfly valve 1 includes a housing 2 provided in the middle of the exhaust pipe, a disc-shaped valve body 3 disposed in the housing 2, and a valve that is pivotally supported by the housing 2 to open and close the valve body 3. A shaft 4 is provided.
An outer end portion of the valve shaft 4 is connected to an actuator (not shown), and a valve body holding portion 5 for holding the valve body 3 is formed at an inner end portion. The exhaust pipe is opened and closed by rotating the valve body 3 through the valve shaft 4 and the valve body holding portion 5 by the actuator.

The housing 2 is formed with a gas passage 2a for accommodating the valve body 3 and a through hole 2b which is formed perpendicularly to the gas passage 2a and supports the valve shaft 4. The gas passage 2a is connected to the exhaust pipe.
A bearing 6 that rotatably supports the valve shaft 4 is press-fitted and fixed in the through hole 2b, and an end surface of the bearing 6 on the gas passage 2a side is an opening portion of the through hole 2b that opens to the gas passage 2a. It is located slightly on the actuator side.
The bearing 6 is press-fitted and fixed in the through hole 2b, thereby sealing between the outer peripheral surface of the bearing 6 and the inner peripheral surface of the through hole 2b in an airtight state.

The valve shaft 4 is rotatably supported by the bearing 6, so that a minute gap is formed between the inner peripheral surface of the bearing 6 and the outer peripheral surface of the valve shaft 4.
The valve shaft 4 and the valve body holding portion 5 are manufactured integrally, and the outer diameter of the valve body holding portion 5 is manufactured to be larger than the outer diameter of the valve shaft 4. A step portion is formed.
The stepped portion is formed with an R shape R having an arcuate cross section, and this R shape R is used for a tool such as an end mill used when the valve shaft 4 and the valve body holding portion 5 are manufactured integrally. It is formed by the tip shape.
In order to reduce the R-shape R, it is necessary to use a tool having a small tip R, which causes problems such as a longer processing time and increased processing steps such as tool replacement.

And in the butterfly valve 1 of the present embodiment, in order to prevent the exhaust gas flowing through the gas passage 2a from flowing out from the through hole 2b, the following between the bearing 6 and the valve body holding portion 5 is as follows. Sealing means are provided.
This sealing means is composed of two stainless steel first and second seal rings 11 and 12. In addition, as the sealing means 11, a material obtained by nitriding stainless steel or an aluminum bronze alloy may be used.
The first seal ring 11 is provided on the bearing 6 side. The outer peripheral surface has a smaller diameter than the through hole 2b, and the inner peripheral surface has a diameter substantially the same as the outer peripheral surface of the valve shaft 4. ing. For this reason, sealing is performed by the inner peripheral surface of the first seal ring 11 and the outer peripheral surface of the valve shaft 4.
The second seal ring 12 is provided on the valve body holding part 5 side, and the outer peripheral surface has a smaller diameter than the through hole 2b, and the inner peripheral surface does not interfere with the R shape R. It has become.
Specifically, the diameter of the inner peripheral surface of the second seal ring 12 is larger than the diameter of the terminal portion on the valve body holding portion 5 side in the R shape R.
Furthermore, the thickness of the second seal ring 12 is such that the inner peripheral surface of the first seal ring does not interfere with the R shape R. Specifically, the first and second seal rings 11 are used. , 12 is sandwiched, the position of the end face on the bearing 6 side of the second seal ring 12 is positioned on the bearing 6 side rather than the position of the terminal portion on the valve shaft 4 side of the R-shaped R. Yes.

With the sealing means having the above configuration, the following sealing effect can be obtained.
When the valve shaft 4 is urged toward the outer peripheral side of the gas passage 2a by the exhaust gas flowing through the gas passage 2a, the end face on the bearing 6 side of the valve body holding portion 5 and the end face on the gas passage 2a side of the bearing 6 The first and second seal rings 11 and 12 are held between them.
As a result, sealing is performed between the end of the bearing 6 on the gas passage 2 a side and the first seal ring 11, and sealing is performed between the end of the valve body holder 5 on the bearing 6 side and the second seal ring 12. Further, the first seal ring 11 and the second seal ring 12 are sealed.
Further, since the seal is performed between the outer peripheral surface of the bearing 6 and the inner peripheral surface of the through hole 2b, and further, the seal is performed between the inner peripheral surface of the first seal ring 11 and the outer peripheral surface of the valve shaft 4. The gas passage 2a and the through hole 2b are sealed by the bearing 6 and the first and second seal rings 11 and 12, and it is possible to prevent the exhaust gas from leaking from the gas passage 2a through the through hole 2b. it can.
When the first and second seal rings 11 and 12 are sandwiched between the end face of the valve body holding part 5 on the bearing 6 side and the end face of the bearing 6 on the gas passage 2a side, the second seal ring 12 Therefore, the R-shape R and the first seal ring 11 do not interfere with each other, so that a seal failure due to deformation or inclination of the first seal ring 11 does not occur.
Further, since a space is formed between the inner peripheral surface of the through hole 2b and the outer peripheral surfaces of the first and second seal rings 11 and 12, soot in the exhaust gas flowing through the gas passage 2a in this space. The first and second seal rings 11 and 12 are not fixed to the through-hole 2b by the scissors even if they are clogged, and the sealing performance by the first and second seal rings 11 and 12 can be maintained for a long time. .
Although neither the inner peripheral surface nor the outer peripheral surface of the second seal ring 12 is in contact with the valve shaft 4 or the through hole 2b, the inner peripheral surface of the second seal ring 12 is the R-shaped R-shaped valve body holding part 5. Since it is located in the vicinity of the outer peripheral side in the radial direction of the side end portion, the second seal ring 12 hardly swings with respect to the first seal ring 11 in practice, and the sealing performance can be maintained.

FIG. 3 shows experimental results for detecting the amount of leakage of exhaust gas to the outside through the through-hole 2b for the butterfly valve 1 of the present embodiment and the conventional butterfly valve 1 shown in Patent Document 1 above. It is.
In this experiment, 100 KPa exhaust gas was circulated in the gas passage 2a as exhaust gas, and the amount of exhaust gas leaked from the through hole 2b was detected.
Further, the valve shaft 4 and the valve body holder 5 used in this experiment have the same shape. In other words, an R-shaped R having the same radius is formed between the valve shaft 4 and the valve body holding portion 5.
As shown in the experimental results, the amount of exhaust gas leakage in the butterfly valve 1 of the present embodiment is less than half of the amount of exhaust gas leakage in the conventional butterfly valve, providing good sealing performance. I can understand that.
In addition, in order to obtain the experimental result (leakage amount: 0.5-4 L / min) described in FIG. 4 of the said patent document 1, it forms between the valve shaft 4 and the valve body holding | maintenance part 5. FIG. Processing to make the R shape R as small as possible is required.

  In addition, although the said Example demonstrated the case where this invention was applied to the butterfly valve 1 of an exhaust brake device, the butterfly valve 1 of the said this Example is a flow control valve of an exhaust-gas recirculation apparatus (EGR), It can also be used for an exhaust throttle valve, an exhaust switching valve, and the like.

Sectional drawing about the butterfly valve concerning a present Example The expanded sectional view of the sealing means vicinity in the said butterfly valve. The figure which shows the experimental result which detected the leakage amount of exhaust gas about a present Example and a conventional product.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Butterfly valve 2 Housing 2a Gas passage 2b Through-hole 3 Valve body 4 Valve shaft 5 Valve body holding | maintenance part 6 Bearing 11 1st seal ring 12 2nd seal ring

Claims (2)

A housing in which a gas passage through which a gas flows and a through hole formed in a direction intersecting the gas passage is formed, a bearing provided in the through hole, and a valve rotatably supported by the bearing A valve body holding portion formed at the end of the valve shaft on the gas passage side and having a larger diameter than the valve shaft, and a valve connected to the valve body holding portion to open and close the gas passage A butterfly valve comprising a body, and a sealing means for sealing between the end portion on the gas passage side of the bearing and the end portion on the bearing side of the valve body holding portion,
An R shape is formed in the step portion formed at the boundary between the valve shaft and the valve body holding portion,
At least one first seal ring that abuts the end of the bearing on the gas passage side to seal the corresponding contact portion, and the end of the valve body holding portion on the bearing side contacts the corresponding contact. A second seal ring that seals the part, and abuts the first seal ring and the second seal ring to seal the corresponding contact part,
Also, the inner peripheral surface of the second seal ring and the R shape are prevented from interfering with each other, and the thickness of the second seal ring is set so that the inner peripheral surface of the first seal ring and the R shape do not interfere with each other. A butterfly valve characterized by its thickness. The bearing is press-fitted into the through hole of the housing to seal between the outer peripheral surface of the bearing and the inner peripheral surface of the through hole,
2. The butterfly valve according to claim 1, wherein a diameter of an outer peripheral surface of each of the first and second seal rings is smaller than a diameter of the through hole.

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