WO2017154204A1

WO2017154204A1 - Valve device

Info

Publication number: WO2017154204A1
Application number: PCT/JP2016/057786
Authority: WO
Inventors: 克典高井
Original assignee: 三菱電機株式会社
Priority date: 2016-03-11
Filing date: 2016-03-11
Publication date: 2017-09-14

Abstract

A valve (33) has a recessed section (33c) in a contact section (33b) that is in contact with a valve seat (35), and when the valve is closed, a contact area between the valve (33) and the valve seat (35) is reduced compared with the case having no recessed section (33c).

Description

Valve device

This invention relates to a valve device for controlling the flow rate of a fluid, and more particularly to a valve device provided on the exhaust side of an engine.

For example, as described in Patent Document 1, in the case of a step type valve in which a valve abuts on a stepped portion provided in a fluid passage, a valve on one side and a back surface on the other side of the valve with the rotation center axis as a boundary Abuts against a stepped portion that is a sheet. At this time, since the outer peripheral curved surface of the valve does not contact the fluid passage, a gap is generated between the outer peripheral curved surface of the valve and the fluid passage. This gap can prevent biting into the fluid passage even if the valve is thermally expanded. In addition, the overlap between the front and back surfaces of the valve and the valve seat prevents the valve and the valve seat from coming into contact with each other due to the difference in the coefficient of linear expansion between the valve and the valve seat. The valve seat leakage can be suppressed.

International Publication No. 2012/001736

However, the structure as described in Patent Document 1 has a large overlap margin, that is, a contact area between the valve seat and the valve when the valve is closed. Therefore, when the structure is applied to a valve device that is provided on the exhaust side of the engine and in which an exhaust gas component flows through a fluid passage, such as an exhaust gas recirculation valve (hereinafter referred to as an EGR valve), for example, Exhaust gas components adhered to the wide overlap margin with the valve seat, and there was a risk of sticking between the valve and the valve seat.

The present invention has been made to solve the above-described problems, and has a structure in which a valve on one side and a back on the other side are in contact with a valve seat with the rotation center axis as a boundary. Even if it exists, it aims at obtaining the valve apparatus which can reduce the possibility of the adhering between the valve | bulb and valve seat by adhesion of an exhaust gas component.

A valve device according to the present invention is provided on the exhaust side of an engine, and a valve shaft that rotates around an axis, a valve that rotates integrally with the valve shaft to open and close a fluid passage, and an annular shape that is provided on an inner surface of the fluid passage A valve seat that abuts against the front surface on one side and the back surface on the other side of the valve shaft with the rotation center axis of the valve shaft as a boundary. The contact portion has a concave portion.

According to the present invention, even if the valve has a structure in which the front surface on one side and the back surface on the other side are in contact with the valve seat with the rotation center axis as a boundary, the valve is in contact with the valve seat. By having a recess in the surface, the risk of sticking between the valve and the valve seat due to the adhesion of exhaust gas components can be reduced.

It is a perspective view which shows the valve apparatus which concerns on Embodiment 1 of this invention. It is a top view which shows a valve | bulb. It is sectional drawing which cut | disconnected the valve | bulb part. It is a figure which expands and shows a part of FIG. It is a figure which shows the modification of the valve apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing which cut | disconnected the valve | bulb part at the time of using a valve seat as a different material from a housing.

Hereinafter, in order to explain the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
FIG. 1 is a perspective view showing a valve device 1 according to Embodiment 1 of the present invention. FIG. 1 shows a case where the valve device 1 is embodied as an EGR valve that circulates engine exhaust gas into an intake passage. The valve device 1 is a step type butterfly valve, and the valve 33 rotates integrally with the valve shaft 32 to open and close the fluid passage 34. As its configuration, the valve device 1 includes an actuator unit 10, a gear unit 20, and a valve unit 30.

The actuator unit 10 has a motor 11 therein and generates a rotational driving force for opening and closing the valve 33. The output shaft of the motor 11 is attached to a gear mechanism disposed inside the gear unit 20.

The gear unit 20 has the gear mechanism inside. The output shaft of the motor 11 and the valve shaft 32 are connected via this gear mechanism, and the rotational driving force of the motor 11 is transmitted to the valve shaft 32 via the gear mechanism.
For example, a pinion gear attached to the output shaft of the motor 11 and the valve shaft 32 are engaged with each other by a gear, and the rotational driving force of the motor 11 is directly transmitted to the valve shaft 32.
As shown in FIG. 1, the actuator unit 10 is attached to the gear unit 20.

The valve section 30 is provided with a fluid passage 34 through which exhaust gas flows in the housing 31 and is connected to a pipe line (not shown) through which exhaust gas flows. The housing 31 is made of, for example, aluminum or stainless steel.
An annular step is provided on the inner surface of the cylindrical fluid passage 34 to form a valve seat 35. The valve 33 is fixed to the valve shaft 32. When the valve shaft 32 rotates around the rotation center axis X by the driving force of the motor 11, the valve 33 also rotates integrally with the valve shaft 32, changing the amount of clearance between the valve seat 35 and the exhaust gas. Control the flow rate. The rotation center axis X corresponds to the axis of the valve shaft 32 itself.

2 is a plan view showing the valve 33 fixed to the valve shaft 32, and FIG. 3 is a cross-sectional view of the valve portion 30 taken along the line AA in FIG. As shown in FIG. 3, the rotation center axis X coincides with the approximate center position of the thickness of the valve 33.
The valve 33 is fixed to the valve shaft 32 using a screw 36. In the bulb 33, an arc-shaped groove 33a is formed on the outer peripheral edge thereof. A similar arc-shaped groove 33a is also formed on the back surface of the valve 33 shown in FIG. 2, so that the valve 33 can be handled without distinction between the front and back sides.
When the valve 33 is closed, the valve 33 abuts on the valve seat 35 at the substantially semicircular surface on one side and the reverse surface of the semicircular side on the other side with the rotation center axis X as a boundary. The contact portion 33b is a portion sandwiched between the broken line L and the edge of the valve 33 in FIG. The contact portion 33 b is a portion of the valve 33 that overlaps the valve seat 35. Although FIG. 2 shows a case where the contact portion 33b is formed on the right side of the paper with the rotation center axis X as a boundary, it is a matter of course that the contact portion 33b may be formed on the left side of the paper surface. As shown in the drawing, the contact portion 33b has a recess 33c formed by a groove 33a in a part thereof.
In FIG. 3, the counterclockwise direction is the valve opening direction of the valve 33.

FIG. 4 is an enlarged view of a part of FIG. Since the valve 33 has the recess 33c in the contact portion 33b with the valve seat 35, the contact area between the valve seat 35 and the valve 33 when the valve is closed is reduced as compared with the case where there is no recess 33c. Therefore, the risk of sticking between the valve 33 and the valve seat 35 due to the adhesion of exhaust gas components can be reduced. Further, the valve 33 and the valve seat 35 overlap with each other over a width h in the drawing, and the valve 33 and the valve seat 35 are not in contact with each other due to a difference in linear expansion coefficient between the valve 33 and the valve seat 35. Is preventing. Thereby, the valve seat leak at the time of valve closing can be suppressed. Further, since the outer peripheral curved surface 33 d of the valve 33 does not contact the fluid passage 34, a gap is generated between the outer peripheral curved surface 33 d and the fluid passage 34. This clearance can prevent biting into the fluid passage 34 even when the valve 33 is thermally expanded.

Further, the recess 33c is connected to the second recess 33e located on the inner peripheral side with respect to the contact portion 33b. The inner peripheral side means a side closer to the center of the valve 33. In the illustrated example, the second concave portion 33e is formed by a portion of the groove 33a on the inner peripheral side with respect to the concave portion 33c. Thereby, the fluid can flow into the concave portion 33c, and the pressure P of the fluid that flows in acts as an assist when the valve 33 is opened.

However, as shown in FIG. 5, the recess 33c may be formed so as to be accommodated in the contact portion 33b. Although assistance at the time of valve opening due to fluid pressure cannot be obtained, the contact area of the contact portion 33b with the valve seat 35 at the time of valve closing can be reduced as compared with the case without the recess 33c. The valve 33 and the valve seat 35 overlap with each other over the width h in FIG. 5 in the same manner as in FIG. 4, and the valve 33 and the valve seat 35 are separated by the difference in the linear expansion coefficient between the valve 33 and the valve seat 35. Equivalent to preventing contact.

The width W from the outer peripheral side edge of the groove 33a forming the recess 33c to the edge of the valve 33 is about 2 mm even when the valve device 1 is large and the diameter of the valve 33 is large. Can be secured. On the other hand, the smaller the valve device 1 is and the smaller the diameter of the valve 33 is, the larger the ratio of the width W to the diameter of the valve 33 becomes. Therefore, it is necessary to suppress the width W to an extent that the ratio can be tolerated. Further, the larger the width W, the easier the sticking between the valve 33 and the valve seat 35 due to the adhesion of exhaust gas components. Considering these things, the width W is preferably set to 2 mm or less, for example. Further, considering the minimum allowable sealing performance, the lower limit value of the width W is, for example, 0.5 mm.

Further, FIG. 2 shows the case where the concave portion 33c is formed by the arc-shaped groove 33a which is not continuous over the entire circumference. Such a groove 33a can be easily formed with a lathe or the like, leading to a reduction in manufacturing cost.
However, the recess 33c may be formed by a plurality of independent arc-shaped grooves arranged on the outer peripheral edge of the bulb 33, a plurality of circular depressions, or a plurality of rectangular depressions. In short, it is sufficient if the contact area of the contact portion 33b with the valve seat 35 when the valve is closed can be reduced as compared with the case where there is no recess 33c. Moreover, in the part which overlaps with the valve axis | shaft 32 among the surface and the back surface of the valve | bulb 33, since it does not contact | abut with the valve seat 35, it is not necessary to provide the groove | channel 33a etc. which form the recessed part 33c in the said part.

Further, the recess 33c does not necessarily have to be formed on both the front surface and the back surface of the bulb 33. If it is formed on at least one of the front surface and the back surface of the valve 33, the contact area between the valve seat 35 and the valve 33 is reduced as compared with the case without the recess 33c. The risk of sticking between the valve seats 35 can be reduced. However, if the arc-shaped groove 33a that forms the recess 33c is provided on both the front and back surfaces of the bulb 33, it is not necessary to distinguish between the front and back sides of the bulb 33, and assembly errors during manufacturing can be prevented.

When the valve 33 and the valve seat 35 are made of the same material or a material having a linear expansion coefficient close to each other, the contact state between the valve 33 and the valve seat 35 is kept almost equal regardless of the temperature change. Valve seat leakage when the valve is closed is effectively suppressed over a wide temperature range. For example, valve seat leakage is effectively suppressed even at high temperatures when high-temperature exhaust gas flows.

For example, the valve 33 is preferably made of stainless steel from the viewpoint of heat resistance, strength, and the like. At this time, considering the linear expansion coefficient, the valve seat 35 may be made of stainless steel. However, when the housing 31 is also made of stainless steel in order to obtain the stainless steel valve seat 35, the cost and weight increase. Therefore, while the valve seat 35 is made of stainless steel, the housing 31 is preferably made of aluminum. This can be achieved, for example, by casting stainless steel in the aluminum housing 31 as the valve seat 35, thereby reducing cost and weight. FIG. 6 is a cross-sectional view of the valve portion 30 taken along line AA in FIG. 1 when the valve seat 35 is made of a material different from that of the housing 31.

In the above description, the valve device 1 is used as an EGR valve. However, the valve device 1 may be used as a valve device other than the EGR valve. By using the valve device 1 as a valve device provided on the exhaust side of the engine, the risk of sticking between the valve 33 and the valve seat 35 due to adhesion of exhaust gas components can be reduced. The valve device 1 can be used, for example, as an exhaust throttle valve, a valve used in an exhaust brake, or the like.

In the above description, the groove 33 a is formed in the valve 33 in order to reduce the contact area between the valve seat 35 and the valve 33. Compared with the valve seat 35, the disk-shaped valve 33 is easy to process the grooves 33a on the front surface and the back surface. However, a contact area between the valve seat 35 and the valve 33 may be reduced by forming a groove in the valve seat 35 instead of the valve 33.

As described above, according to the valve device 1 according to the first embodiment, the valve 33 has the concave portion 33c in the contact portion 33b with the valve seat 35, and the valve 33 and the valve seat 35 are closed when the valve is closed. The contact area is reduced as compared with the case where there is no recess 33c. Therefore, the risk of sticking between the valve 33 and the valve seat 35 due to the adhesion of exhaust gas components can be reduced.

Further, the recess 33c is connected to the second recess 33e located on the inner peripheral side with respect to the contact portion 33b. If it does in this way, the assist at the time of opening valve 33 can be obtained.

Further, the recess 33c is formed by an arc-shaped groove 33a. Since the arc-shaped groove 33 a is a groove along the shape of the outer edge of the bulb 33, it is easy to process and form the bulb 33.

Further, the groove 33a is formed on the front surface and the back surface of the bulb 33. In this way, it is not necessary to distinguish between the front and back sides of the valve 33, and assembly errors can be prevented.

In addition, the width from the outer peripheral edge of the groove 33a to the edge of the bulb 33 is 2 mm or less. In this way, the valve device 1 can be designed to function appropriately as a valve device while considering the difficulty of sticking between the valve 33 and the valve seat 35.

In addition, the material of the valve 33 and the material of the valve seat 35 are the same. By aligning the linear expansion coefficients in this manner, valve seat leakage during valve closing is effectively suppressed in a wide temperature range.

Further, the valve 33 and the valve seat 35 are made of stainless steel, and the housing 31 in which the fluid passage 34 is formed is made of aluminum. In this way, the cost and weight of the housing 31 can be reduced.

In the present invention, any component of the embodiment can be modified or any component of the embodiment can be omitted within the scope of the invention.

As described above, the valve device according to the present invention is suitable for use as, for example, an EGR valve because it has a structure that can reduce the risk of sticking between the valve and the valve seat due to adhesion of exhaust gas components.

1 valve device, 10 actuator part, 11 motor, 20 gear part, 30 valve part, 31 housing, 32 valve shaft, 33 valve, 33a groove, 33b abutting part, 33c concave part, 33d outer peripheral curved surface, 33e second concave part, 34 fluid passage, 35 valve seat, 36 screws.

Claims

A valve shaft that rotates about an axis;
A valve that rotates integrally with the valve shaft to open and close the fluid passage;
An annular step provided on the inner surface of the fluid passage, comprising a valve seat abutting on one side surface and the other side back surface of the valve with the rotation center axis of the valve shaft as a boundary;
The said valve has a recessed part in the contact part with the said valve seat in the said surface or the said back surface, The valve apparatus provided in the exhaust side of an engine characterized by the above-mentioned.
The valve device according to claim 1, wherein the concave portion is connected to a second concave portion located on an inner peripheral side with respect to the contact portion.
The valve device according to claim 1, wherein the recess is formed by an arc-shaped groove.
4. The valve device according to claim 3, wherein the groove is formed on the front surface and the back surface.
The valve device according to claim 3, wherein a width from an outer peripheral edge of the groove to an edge of the valve is 2 mm or less.
The valve device according to claim 1, wherein the material of the valve and the material of the valve seat are the same.
The valve device according to claim 1, wherein the valve and the valve seat are made of stainless steel, and the housing in which the fluid passage is formed is made of aluminum.