JP2000110951A - Butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the gas pressure in the upstream while the valve element of a butterfly valve is in the middle position from half opening to full opening from exceeding the gas pressure in the full close condition. SOLUTION: A concave part in spherical form 24a are formed upstream and downstream of that cylindrical inner surface region of a valve body 23 including an area confronting the valve element 4 to be rotated, and a pressure regulating groove 24c is formed from the part nearer the upstream to a certain extent of the center of the concave part 24a toward the downstream, and the pressure of the passing gas is adjusted by rotating the valve element 4, and thus a butterfly valve 21 is constructed, wherein a bypass passage 30 is formed in the concave part 24a to put the upstream and down stream in mutual communication in the condition that the valve element 4 is intermediately opened from the position where no gas pressure is applied in the upstream as the starting point when the valve element 4 is to be closed, and the position at the upstream end of the groove 24c and the position at the upstream end 31 of the bypass passage 30 are formed in the mutual overlapping region C for opening and closing of the valve element 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve in which the upper limit of the upstream pressure during the transition from a half-open state to a fully closed state does not exceed the upstream pressure in the fully closed state. In particular, the present invention relates to a butterfly valve suitable for an exhaust brake valve used for an exhaust brake device mounted on an automobile or the like, a warming valve used for a warming device, and the like.

[0002]

2. Description of the Related Art Exhaust brake devices are installed mainly in trucks and buses, and close an exhaust brake valve disposed in the exhaust pipe of an engine, that is, a butterfly valve to increase exhaust gas pressure. The vehicle is effectively braked on a long downhill road or the like.

Conventionally, as this type of butterfly valve, for example, there is one shown in FIG. In FIG. 4, the butterfly valve 1 includes a valve body 3 forming a part of an exhaust gas passage 2 of an engine, and a disc-shaped valve body 4 disposed inside the valve body 3. The rotary shaft 5 supporting the valve body 4 is connected to the valve body 3 via cylindrical bearing members (bushes) 6 and 7 and a packing (seal ring or labyrinth seal) 8.
Is mounted to be rotatable.

[0004] At the axial position of the drive shaft of the actuator (not shown), a rotational driving force is transmitted from the actuator to a lever 9 fixed to one end of the rotary shaft 5, and the rotary shaft 5 is rotated. The exhaust gas passage 2 is opened and closed by the valve body 4. FIG.
Indicates a valve open state.

When the exhaust valve operates, that is, when the exhaust valve 2 completely closes the exhaust gas passage 2 when the exhaust valve is operated, that is, when the valve element 4 is closed, the butterfly valve 1 exhausts gas. Acts on the engine as excessive load,
Therefore, the engine is stopped. Therefore, a small gap is provided between the valve body 4 and the peripheral surface of the exhaust gas passage 2 or a hole is formed in the valve body 4 without completely closing the exhaust gas passage 2. are doing.

During operation of the exhaust brake device or the warm-up device, high-speed exhaust gas discharged from the gap between the valve body 4 and the valve body 3 flows through the wall surface 3a of the valve body 3, so that Friction often caused the airflow noise of "shoe". There is a problem that the airflow noise propagates to the outside and causes noise. For this reason, the driver of the car has been uncomfortable.

When the butterfly valve 1 is operated,
In particular, immediately before closing the valve, the gap (exhaust gas passage area) between the peripheral portion of the valve element 4 and the valve body 3 changes, so that the exhaust gas pressure and the exhaust gas flow rate with respect to the angle of the valve element 4. Greatly changed, the adjustment was difficult, the performance of the brake device and the warming device was likely to be unstable, and there was a possibility that white smoke and black smoke were discharged.

For this reason, the present inventors have improved the butterfly valve 1 and have already proposed a butterfly valve shown in FIG. That is, in FIGS. 5 and 6,
The butterfly valve 11 has a valve body 4 fixed to a rotating shaft 5 disposed inside a valve body 13 forming a part of the gas passage 2, and rotates the rotating shaft 5 to rotate the valve body. 4, the gas passage 2 is opened and closed. And the valve body 1
3, a concave spherical block 14 is formed on and downstream of the cylindrical inner peripheral surface including a region facing the valve element 4 which is rotated by the rotation shaft 5. A streamline block 15 having a streamline curved surface 15a is connected or connected to the upstream side of the spherical block 14.

A pressure adjustment groove (or pressure change amount adjustment groove) 14a is formed upstream or downstream (downstream in FIG. 5) from the central portion of the concave spherical block 14, and the valve is provided. The rotation of the body 4 adjusts the pressure of the passing gas (pressure change amount). (Japanese Patent Application Hei 10-250
No. 588) Further, the concave spherical block 1 of the butterfly valve 11
4, when the valve body 4 is closed (valve closing position d), the upstream side and the downstream side communicate with each other at an intermediate opening position b of the valve body 4 starting from a position where the gas pressure on the upstream side is not applied. A bypass passage 16 is formed. (Corresponds to Figure 8 in Japanese Patent Application No. 10-250588)

[0010]

In such a butterfly valve 11, according to the figure showing the change of the exhaust gas pressure on the upstream side with respect to the valve angle in FIG.
However, the exhaust gas pressure in the range of the valve angle A from the fully open state (the valve body 4 is at a position parallel to the passage axis) to the valve position a is such that the exhaust gas flows downstream through the bypass passage 16. As it flows, it gradually rises and becomes constant at the valve position a. Thereafter, the exhaust gas pressure becomes constant in a range B (half-open state) up to the valve position b.

Next, when the valve body 4 is in the range of the valve angle C from the valve position b to the valve position c, the pressure adjusting groove 1
Since the opening end of the bypass passage 16 is closed without communicating with the exhaust gas 4a, the exhaust gas pressure rises rapidly. Thereafter, the valve element 4 communicates with the pressure adjusting groove 14a in the range of the valve angle D from the valve position c to the valve position d (fully closed state), and gradually increases the opening area according to the valve angle. Therefore, the exhaust gas pressure gradually rises after dropping.

However, in the range of the valve angle C during the transition of the valve element 4 from the half-open state to the fully closed state, the exhaust gas pressure sharply increases, and often the exhaust gas pressure increases.
There is a problem that the exhaust gas pressure exceeds the exhaust gas pressure in the fully closed state of the valve body 4 in the range of the valve angle D where the valve 4a communicates, and the engine may be broken down. .

The present invention has been made in view of such a point.
The object of the present invention is to solve the above-mentioned problem and to provide a butterfly in which the exhaust gas pressure on the upstream side at the intermediate position between the half-open position and the fully closed position does not exceed the gas pressure in the fully closed state when the valve is closed. It is to provide a valve.

Another object of the present invention is, for example, a butterfly valve used for an exhaust brake valve of an exhaust brake device mounted on an automobile or the like, a warming valve of a warming device, and the like. An object of the present invention is to provide a butterfly valve in which an exhaust gas pressure and an exhaust gas flow rate at a close intermediate position are stabilized.

[0015]

According to a first aspect of the present invention, a valve body fixed to a rotating shaft is provided inside a valve body forming a part of a gas passage. A valve that rotates the rotation shaft and opens and closes the gas passage by the valve body, and includes an inner peripheral surface of the valve body and a region facing the valve body that is rotated by the rotation shaft. On the inner peripheral surface of the cylinder, on the downstream side, a concave spherical shape portion is formed, and on the upstream side of the concave spherical shape portion, a streamline portion having a streamline curved surface is connected, and the concave spherical shape portion is formed. A pressure change amount adjusting groove is formed upstream or downstream from a central portion of the butterfly valve, and the pressure change amount of the passing gas is adjusted by the rotation of the valve body.

The pressure change amount adjusting groove is formed on the downstream side from a portion slightly closer to the upstream side of the central portion of the concave spherical shape portion, and is formed in the concave spherical shape portion when the valve body is closed. Starting from a position where the gas pressure is not applied, a bypass passage communicating between the upstream side and the downstream side at the intermediate opening position of the valve body is formed, and the pressure change amount with respect to opening and closing of the valve body is formed. The position of the upstream end of the adjustment groove and the position of the upstream end of the bypass passage are formed in a region overlapping each other.

The intermediate opening position of the valve element is between the half-open position and the valve closing position of the valve element.

The bypass passage includes a through hole that opens on the valve body side and an expansion chamber that communicates with the downstream side, and the length of the through hole is 0.7 to 2 mm.

Further, the material of the concave spherical shape portion and the streamline portion is made of martensitic heat-resistant steel having high corrosion resistance and heat resistance to exhaust gas of an engine.

Further, from the upstream end of the valve body,
An assembling groove for assembling the rotating shaft to which the valve body is fixed is provided on an inner wall surface of the concave spherical portion reaching a portion where the rotating shaft is supported.

Since the present invention is configured as described above, a concave spherical portion is formed at the center of the valve body, and the operating angle of the valve body of the butterfly valve is changed from a half open state to a fully closed state. The upper limit or the maximum value of the exhaust gas pressure on the upstream side at the intermediate position is not larger than the gas pressure in the fully closed state to protect the engine.

Since the through-hole, which constitutes the bypass passage and opens to the valve body, has a passage shape communicating with the inside of the valve body, there is a concern that the exhaust gas pressure may increase due to the accumulation of carbon contained in the exhaust gas. However, the through hole
An orifice-shaped thin aperture (length direction of the through-hole) is used to form a thin aperture to form a half-open pressure relief hole that does not cause carbon deposition or increase in exhaust pressure. Exhaust gas passing through the pressure relief hole (the through hole) having a small thickness (length) is introduced into the expansion chamber communicating therewith without adhering carbon to the periphery thereof. Therefore, there is no effect on the exhaust pressure.

Further, the bottom surface is the inner peripheral surface of the valve body, and the depth of the central portion is shallow.
Since the change of the back pressure with respect to the valve angle of the adjusting groove is small, it is possible to adjust the small flow rate of the exhaust gas. Therefore, when the butterfly valve is operated, adjustment of the exhaust gas pressure and the exhaust gas flow rate becomes easy.

[0024] Since a groove for assembling the rotary shaft to which the valve body is fixed is provided on the inner wall surface on the downstream side of the valve body, productivity and maintainability of the butterfly valve are improved. I have.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 3
1 shows an embodiment of a butterfly valve according to the present invention, and FIG.
FIG. 2 is a cross-sectional view, FIG. 2 is a diagram showing a positional relationship between the pressure adjusting groove and the bypass passage with respect to the valve angle of the valve body, and FIG. 3 is a diagram showing a change in the exhaust gas pressure on the upstream side with respect to the valve angle. 4
7 to the same members or the same parts as those in FIG.

In FIG. 1, a butterfly valve 21 in this embodiment is used as an exhaust brake valve of an exhaust brake device or a warm-up valve of a warm-up device. The butterfly valve 21 has mounting flanges at one end and near a support hole of the rotary shaft 5 to which the valve body 4 is fixed, and has a substantially cylindrical valve body forming a part of the exhaust gas passage 2. 23, a concave spherical block 24 fitted in the valve main body 23 to form the internal passage 22, and a concave spherical block 24 similarly fitted in the valve main body 23 to form the internal passage 12. 2
A streamline block 25 joined to the upstream side of the rotary shaft 4 and the rotating shaft 5 disposed in the concave spherical block 24 so as to be openable and closable.
And a disc-shaped valve element 4 fixed to the valve body.

The concave spherical block 24 is press-fitted from the exhaust gas upstream side of the valve body 23, and the upstream exhaust gas acting on the side surface of the concave spherical block 24 via the streamline block 25. The gas pressure causes the valve body 23 to come into contact with a step 23 a provided on the valve body 23. The concave spherical block 24 may be formed integrally with the valve main body 23, and the streamline block 25 may be formed integrally with the valve main body 23.

The valve body 23 communicates with the internal passage 22 in the same manner as the structure shown in FIG.
2, a pair of rotary shaft support holes formed concentrically on both sides so as to cross the shaft 2. Inside these support holes, cylindrical bearing members (bushings) 6, 7 are tightly fitted. By press fitting. And the bearing members 6, 7
The rotary shaft 5 supporting and fixing the valve body 4 is rotatably attached to the valve body 23. Also,
The one or both rotation shaft support holes, particularly the rotation shaft 5
The exhaust gas flowing through the exhaust gas passage 22 is sealed by a packing (seal ring or labyrinth seal) 8 so as not to leak outside.

Then, a rotational driving force is transmitted from the actuator to the lever 9 fixed to one end of the rotary shaft 5, the rotary shaft 5 is rotated, and the exhaust gas passage 22 is The valve 4 opens and closes. The solid line and the dashed line of the valve element 4 in FIG.
The state of the valve element 4 at each position where the state shifts from the half-open state to the fully closed state is shown.

Next, in FIG. 1, the concave spherical block 24 fitted to the inner peripheral surface of the valve main body 23 of the butterfly valve 21
With the rotation of the valve body 4, a concave spherical shape portion 24a is formed on the upstream side and the downstream side around the rotation shaft 5 over a region opposed to the peripheral portion of the valve body 4 which is opened and closed.

The streamline block 25, which is arranged and joined to the upstream side of the concave spherical block 24, has an upstream end of the concave spherical portion 24a and an inner peripheral surface of an upstream end of the valve body 23. Is formed by a streamline portion 25a having a smooth streamlined curved surface as much as possible, and the streamline portion 25a connects both ends smoothly to minimize the pressure loss of gas passing therethrough. I have. In addition, the concave spherical block 2
4 between the downstream end of the concave spherical shape portion 24a and the downstream inner peripheral surface of the valve body 23.
The inner diameter of the valve body 23 side, which is larger than the inner diameter of the downstream end of the valve body 23, forms an edge-shaped step portion 24b, which is connected by the step portion 24b.

In this embodiment, the material of the valve body 23 is low-cost gray cast iron, and the material of the concave spherical block 24 and the streamline block 25 is corrosion resistant and heat resistant to engine exhaust gas. Large martensitic heat-resistant steel is used.

On the other hand, the bottom surface is formed on the inner peripheral surface of the valve main body 23 from a portion slightly upstream of the central portion of the concave spherical shape portion 24a formed on the inner peripheral surface of the concave spherical block 24 to the downstream side. A single or a plurality of (in this embodiment, a single) pressure adjustment groove 24c is formed as an intermediate-pressure exhaust-pressure adjustment groove parallel to. Since the depth thereof is relatively shallow in the central portion of the concave spherical shape portion 24a, the rotation of the valve body 4 immediately before the valve closes causes the adjustment spherical shape of the concave spherical shape portion 24a of the adjusting groove 24c. The amount of pressure change of the exhaust gas passing near the central portion can be finely adjusted. The shape of the pressure adjusting groove 24c can be arbitrarily determined in order to obtain a pressure and a flow rate with respect to a desired valve angle.

Further, as shown in FIG. 1, the concave spherical block 24 is provided at a position facing the position of the pressure adjusting groove 24c at a position where the exhaust gas pressure is not applied when the valve body 4 is closed. And the intermediate opening positions b to c of the valve body 4
In the range C, a bypass passage 30 that connects the upstream side and the downstream side is formed. The bypass passage 30 is
Specifically, the length of the opening on the valve body 4 side is 0.7 to 2 m.
m (in this embodiment, 0.7 mm), the through-hole 31 communicates with the through-hole 31 and the downstream side, and the concave spherical block 2
Expansion chamber 32 formed between the valve body 4 and the valve body 23
Consists of

The through hole 31 opening to the valve body 4 side
Is a orifice-like thin (longitudinal) orifice with a passage area of approximately 7.1 mm ² , and has a shape of a half-open pressure relief hole that prevents carbon deposition and exhaust pressure rise. . The through hole (pressure relief hole) 31 having a small thickness.
The exhaust gas passing therethrough is introduced into the expansion chamber 32 communicating therewith without adhering or accumulating carbon around the exhaust gas. In the expansion chamber 32, the gas flow velocity decreases, so that carbon in the exhaust gas adheres and easily accumulates. However, since the passage area is large, for example,
Adhesion has no effect on exhaust gas pressure. Therefore,
The minimum passage area of the bypass passage 30 always has a length of
Since the through hole (pressure relief hole) 31 has a diameter of 0.7 to 2 mm, there is no fluctuation in exhaust pressure due to carbon adhesion.

The upstream end 2 of the pressure adjusting groove 24c
The position of 4d and the position of the through hole 31 at the upstream end of the bypass passage 30 are in a region where the opening and closing of the valve element 4 overlap each other, and in a region of the valve angle C shown in FIG. Is formed.

That is, according to FIG. 2 and FIG. 3, the exhaust gas pressure in the range of the valve angle A from the fully opened state to the valve position point a when the exhaust gas passes through the bypass passage 30 is shown. Flow to the downstream side, so that it gradually rises and becomes constant at the valve position a.
(Half-open state) and remains constant.

Next, in the range of the valve angle C from the valve position b to the valve position c, the valve body 4 gradually closes the through-hole (opening) 31 of the bypass passage 30 while controlling the pressure adjustment. Since the upstream end 24d of the groove 24c is gradually communicated, the exhaust gas pressure is substantially constant without increasing, and its value (maximum value) does not exceed the gas pressure in the fully closed state. . At this time, the passage area of the through hole (opening) 31 of the bypass passage 30 and the pressure adjustment groove 24
The sum with the passage area of the upstream end 24d of c is changed smoothly according to the valve angle. Thereafter, the valve element 4 communicates with the pressure adjusting groove 24c in the range of the valve angle D from the valve position c to the valve position d (fully closed state), and gradually increases the opening area according to the valve angle. Expanding, the exhaust gas pressure rises slowly.

FIG. 3 shows that the exhaust gas pressure is 0 mmHg when the valve element 4 is fully open and 35 mm when the valve element 4 is half open.
0 mmHg and 650 mmHg when fully closed. Since the exhaust gas pressure is inversely proportional to the passage area, the passage area changes gradually and smoothly when the butterfly valve 21 transitions from fully open to fully closed.

Further, in order to facilitate the assembly of the rotary shaft 5 to which the valve element 4 is fixedly attached to the valve body 23, a substantially central portion of the concave spherical block 24 is provided from the upstream end of the valve body 23. Two mounting grooves 26 formed parallel to the gas passage are provided on the inner wall surface leading to the (rotational shaft 5 mounting portion).

Note that the technology of the present invention is not limited to the technology in the above-described embodiment, and may be implemented by means of other modes that perform the same function. Various changes and additions are possible.

[0042]

As is apparent from the above description, according to the butterfly valve of the present invention, the pressure variation adjusting groove is formed downstream from a portion slightly closer to the upstream side of the central portion of the concave spherical shape portion, When the valve body is closed, a bypass passage communicating with the upstream side and the downstream side at an intermediate opening position of the valve body is formed in the concave spherical shape portion, starting from a position where the gas pressure on the upstream side is not applied when the valve body is closed. In addition, the position of the upstream end of the pressure change amount adjusting groove and the position of the upstream end of the bypass passage are formed in an overlapping area with respect to the opening and closing of the valve body. In particular, the gas pressure on the upstream side at the intermediate position of the valve element from the half-open state to the fully closed state does not exceed the gas pressure in the fully closed state, and therefore, there is no possibility that the engine may fail.

Also, the butterfly valve of the present invention
If used for the exhaust brake valve of an exhaust brake device installed in an automobile, etc., or the warming valve of a warming device, the exhaust gas pressure and exhaust gas flow are stabilized during operation, especially in the intermediate position near the valve closing. Is done. Further, since an assembling groove for assembling the rotary shaft to which the valve body is fixed is provided on the inner wall surface on the upstream side of the valve body, productivity and maintainability of the butterfly valve are improved. Have been.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a positional relationship between a pressure adjusting groove and a bypass passage with respect to a valve angle of the valve body of FIG. 1;

FIG. 3 is a diagram showing a change in upstream exhaust gas pressure with respect to the valve angle in FIG. 1;

FIG. 4 is a sectional view showing a conventional butterfly valve.

FIG. 5 is a cross-sectional view showing an improved conventional butterfly valve.

6 is a diagram showing a positional relationship between a pressure adjustment groove and a bypass passage with respect to a valve angle of the valve body of FIG. 5;

FIG. 7 is a diagram showing a change in upstream exhaust gas pressure with respect to the valve angle in FIG. 5;

[Explanation of symbols]

 2, 22 Exhaust gas passage 4 Valve body 5 Rotary shaft 11, 21 Butterfly valve 13, 23 Valve body 14, 24 Concave spherical block 14a, 24c Pressure adjustment groove (pressure change amount adjustment groove) 15, 25 Streamline block 15a, 25a Streamline curved surface or streamline portion 24a Concave spherical shape portion 24d Upstream end 26 Assembly groove 30 Bypass passage 31 Through hole 32 Expansion chamber

Claims (5)

[Claims] 1. A valve body fixed to a rotating shaft is disposed inside a valve body forming a part of a gas passage, and the rotating shaft is rotated to open and close the gas passage by the valve body. A concave spherical shape portion is formed on the inner peripheral surface of the valve main body, on the downstream side above the cylindrical inner peripheral surface including a region facing the valve body rotated by the rotation shaft. A streamline portion having a streamline curved surface is connected to the upstream side of the concave spherical shape portion, and a pressure change amount adjusting groove is provided upstream or downstream from a central portion of the concave spherical shape portion. Formed,
In the butterfly valve, in which the pressure change amount of the gas passing therethrough is adjusted by the rotation of the valve body, the pressure change amount adjustment groove extends from a portion slightly closer to the upstream side of the central portion of the concave spherical shape portion to the downstream side. A bypass formed in the concave spherical shape portion and communicating the upstream side and the downstream side at an intermediate opening position of the valve body from a position where the gas pressure on the upstream side is not applied when the valve body is closed. A passage is formed, and the position of the upstream end of the pressure change amount adjusting groove and the position of the upstream end of the bypass passage are formed in an overlapping region with respect to opening and closing of the valve body. A butterfly valve characterized by the following. 2. The butterfly valve according to claim 1, wherein the intermediate opening position of the valve element is between a half-open position and a valve closing position of the valve element. 3. The bypass passage includes a through hole that opens on the valve body side and an expansion chamber that communicates with the downstream side, and the length of the through hole is 0.7 to 2 mm. The butterfly valve according to claim 1. 4. The butterfly according to claim 1, wherein the material of the concave spherical shape portion and the streamline portion is martensitic heat-resistant steel having high corrosion resistance to engine exhaust gas and heat resistance. valve. 5. An assembling method for assembling the rotary shaft, wherein the valve body is fixed to an inner wall surface extending from an upstream end of the valve body to a portion of the concave spherical portion where the rotary shaft is supported, 2. An assembly groove is provided.
Butterfly valve according to 1.