JPH07269376A - Butterfly valve - Google Patents

Abstract

PURPOSE:To make minimum the finish processing of the valve seat portion inner surface of a butterfly valve and reduce man-hours by projecting inward an annular valve seat portion having a flow passage direction width equivalent to at least the thickness of the outer periphery edge portion of a valve body, on the inner periphery surface of a body opposite to the outer periphery edge position of the valve body at the time of valve opening. CONSTITUTION:A butterfly valve 1 is applied to, for example, an exhaust shutter for exhaust brake, and a valve body 4 falls into a valve opening state by coming into contact with a valve seat portion 6 at a fixed inclination angle theta, in regard to the axis center of a body 2 and becomes fully opened in the state of being in parallel with the axis center. The valve seat portion 6 forms an annular shape that inclines at the same angle on the inner periphery surface of the body 2 opposite to the outer periphery edge position of the valve body 4 at the time of valve closing and a integrally cast by being projected a little inward, and the inner periphery surface is made to be a finish surface of high precision by cutting or grinding processing. As a portion that projects as the valve seat portion 6 in the body 2 forms an annular shape and its flow passage direction width is short, the range of finish processing necessary for contact with the valve body 4 is made minimum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve applied to, for example, an exhaust shutter for an exhaust brake provided in an exhaust gas passage of an automobile engine.

[0002]

2. Description of the Related Art Conventionally, as a butterfly valve of this type,
There is known a structure in which a disc-shaped valve body forming an ellipse is rotatably supported around an axis orthogonal to the internal flow passage in a cylindrical body having an internal flow passage extending in the axial direction thereof. ing.

The body of such a butterfly valve is
It is generally made of cast products, and its inner peripheral surface is
In order to improve the fluid tightness when the valve is closed, the entire inner peripheral surface is finished with high precision by machining such as cutting or polishing.

[0004]

In the above-mentioned conventional butterfly valve, since the entire inner peripheral surface of the body is subjected to high-precision finishing, a large number of man-hours are required for cutting or polishing and the productivity is increased. And the consumption of cutting tools and grindstones, etc., resulting in economical waste.

The present invention has been made in view of the above circumstances, and provides a butterfly valve in which the finishing work on the inner surface of the body is minimized, the number of man-hours at the time of manufacturing is reduced, and the manufacturing is inexpensive. The purpose is to

[0006]

In order to achieve the above-mentioned object, the present invention is supported in a body having a cylindrical internal flow passage so as to be rotatable about an axis orthogonal to the internal flow passage. In a butterfly valve containing a disc-shaped valve body, the inner peripheral surface of the body corresponding to the outer peripheral edge position of the valve body when the valve is closed, at least the wall thickness of the outer peripheral edge portion of the valve body. An annular valve seat portion having a corresponding flow direction width,
It is characterized in that it is formed so as to project inward of the body.

In the present invention, preferably, the body is preferably formed by casting, and the inner peripheral surface of the valve seat portion is cut or polished to provide a highly accurate finished surface (claim 2). Further, it is desirable that the body is made of a pipe having a valve seat portion that is projected inward by plastic working, and that the inner peripheral surface of the valve seat portion is a highly accurate finished surface by cutting or polishing. Good (Claim 3).

[0008]

According to the above-mentioned structure, since the portion projecting as the valve seat portion in the body is annular and has a short width in the flow passage direction, the finishing work required for contact with the valve body can be achieved. The range is extremely small compared with the conventional one.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view of a central portion of a butterfly valve body, and FIG. 2 is a partially cutaway exploded perspective view of the entire butterfly valve.

The butterfly valve (1) of this embodiment is composed of a cylindrical cast product and has a body (2) having an internal flow path (2a) along the axial direction (a), and the inside of this body (2). And an elliptical disk-shaped valve body (4) rotatably supported via an axis (3) orthogonal to the internal flow path (2a).

The butterfly valve (1) is connected to an exhaust pipe (5) of an automobile engine, for example, and is used as an exhaust shutter for an exhaust brake.

The valve body (4) contacts the valve seat (6) at a constant inclination angle (θ) with respect to the axis of the body (2),
The valve is set to be in a closed state (solid line in FIG. 1) and fully open in a state parallel to the axis of the body (2) (imaginary line in FIG. 1).

In this structure, the valve seat portion (6) is formed on the inner peripheral surface of the body (2) corresponding to the outer peripheral edge position of the valve body (4) when the valve is closed, at the same angle as the angle (θ). It is formed in a slanting annular shape, and is integrally cast by slightly projecting inward of the body (2). The dimension (b) of the valve seat portion (6) along the flow path direction is set to be slightly larger than the wall thickness of the outer peripheral edge portion of the valve body (4). Inner surface (6
In a), the finished surface has high precision by cutting or polishing.

When the valve is used, the shaft (3) of the valve body (4) is rotated about the shaft (3) by a predetermined angle by a drive mechanism (not shown) (see arrow (c) in FIG. 1). As described above, the valve body (4) is brought into contact with the valve seat portion (6) to close the valve, and the valve is fully opened when the angle (θ) becomes zero.

According to the butterfly valve (1) of this embodiment constructed as described above, the portion projecting as the valve seat portion (6) in the body (2) is annular and has a short width in the flow path direction. Therefore, the range of finishing required for contact with the valve body (4) is extremely small compared with the conventional case. For example, when this finishing process is performed by cutting with a cutting tool, the holding of the tool is improved, and when it is performed by polishing, the holding of the grindstone is improved. To be Further, the work efficiency is improved by the reduction of the processing range and the productivity is increased, which leads to the reduction of the product cost.

FIG. 3 shows another embodiment of the present invention (an embodiment of the invention described in claim 3). In this embodiment, the body (2) is formed of a pipe and one of its outer peripheral surface is formed. The valve seat portion (6) is formed by reducing the diameter of the portion by plastic working (drawing) and slightly projecting it inward.

The inner peripheral surface of the valve seat portion (6) is the same as described above.
It has a high-precision finished surface by cutting or polishing.
According to this embodiment, there is an advantage that the manufacturing process can be remarkably simplified as compared with the one formed by the above-mentioned casting.
The dimension (b) of the valve seat portion (6) of the present invention does not necessarily have to be the same as that of the above-mentioned embodiment, and is approximately the same as the wall thickness of the outer peripheral edge portion of the valve body (4). Good.

[0018]

As described in detail in the above embodiments, according to the inventions of claims 1 to 3, the size of the valve seat portion integrated with the body can be minimized to reduce the finishing work on the inner surface of the body. By doing so, the number of manufacturing steps can be reduced, the productivity can be improved, and an inexpensive butterfly valve can be provided. Particularly, according to the invention of claim 3, since the manufacturing process is simplified, a cheaper butterfly valve can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts showing an embodiment of a butterfly valve according to the present invention.

FIG. 2 is a partially cutaway exploded perspective view showing the overall configuration of the embodiment.

FIG. 3 is a vertical sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 (1) Butterfly valve (2) Body (3) Shaft (4) Valve body (6) Valve seat (6a) Inner peripheral surface

Claims (3)

[Claims] 1. A body having a cylindrical internal flow path,
A butterfly valve comprising a disc-shaped valve body rotatably supported about an axis orthogonal to the internal flow path, the butterfly valve having an inner peripheral portion of the body corresponding to an outer peripheral edge position of the valve body when the valve is closed. A butterfly valve, characterized in that an annular valve seat portion having a width in the flow passage direction corresponding to at least the thickness of the outer peripheral edge portion of the valve body is formed on the peripheral surface so as to project inward of the body. 2. The butterfly valve according to claim 1, wherein the body is formed by casting, and the inner peripheral surface of the valve seat portion has a highly accurate finished surface by cutting or polishing. 3. The body is made of a pipe having a valve seat portion that is projected inward by plastic working, and the inner peripheral surface of the valve seat portion is a highly accurate finished surface by cutting or polishing. The butterfly valve according to claim 1, which is characterized in that.