JPH08319903A - Exhaust gas recirculation control valve - Google Patents

Abstract

PURPOSE: To reduce the number of component parts and to miniaturize a control device as a whole by providing one diaphragm, which divides the inside of a case into a vacuum chamber and an atmospheric pressure chamber, in the case and deforming the diaphragm in order to move a rod. CONSTITUTION: A diaphragm 5 is provided, which is installed in a case 1 composed of an upper case 2 and a lower case 2 and which divides the inside of the case 1 into a vacuum chamber 11 and an atmospheric pressure chamber 10. A rod 6 is provided, which goes through the lower case 3 and whose one end is connected to the diaphragm 5. A valve 7 is provided, which is connected to the other end of the rod 6 and which is situated in a flow passage 16, in which the exhaust gas flows, in order to open or close a part of the flow passage 16. In addition, a bush 12 is provided, which is attached to the lower case 3 in order to support the rod 6 in a freely movable manner. With this, the number of parts can be reduced, thereby simplifying the structure as a whole and miniaturizing the control device as a whole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation control valve, and more particularly to an exhaust gas recirculation control valve used for recirculating exhaust gas from an automobile engine or the like and having a valve operated by negative pressure. It is about valves.

[0002]

2. Description of the Related Art Generally, an exhaust gas recirculation control valve having a valve which is used to recirculate exhaust gas from an automobile engine or the like and which operates by negative pressure is shown in FIG. Is configured.

That is, this recirculation control valve is provided in a case 31 composed of an upper case 32 and a lower case 33, and in the case 31, there are two chambers, an atmospheric pressure chamber 40 and a negative pressure chamber 41. Diaphragm 35
A rod 36 having one end connected to the center of the diaphragm 35 through the lower case 33, and a valve connected to the other end of the rod 36 and opening / closing a part of a flow path 46 through which exhaust gas flows. 37 and.

The diaphragm 35 is made of an elastic material such as rubber and has a disk shape. The peripheral edge of the diaphragm 35 is sandwiched between the peripheral edge of the upper case 32 and the peripheral edge of the lower case 33. ing.

An atmospheric pressure chamber 4 is provided on the upper surface side of the diaphragm 35.
0 is formed, the inside of the atmospheric pressure chamber 40 is opened to the atmosphere through a hole 32a provided at the top of the upper case 32, and the negative pressure chamber 41 is formed on the lower surface side of the diaphragm 35. Is connected to a pressure supply source (not shown) via a pipe member 38 provided on the side of the lower case 33.

The lower case 33 has a double structure composed of an inner case 34a and an outer case 34b, and a rod 36 is inserted through the central portion thereof.

A sealing diaphragm 39 made of an elastic material such as rubber is attached to the rod insertion portion of the inner case 34a, and the sealing diaphragm 39 seals between the inner case 34a and the rod 36, so that a negative pressure is applied. The inside of the chamber 41 is completely sealed.

A bush 42 is attached to the rod insertion portion of the outer case 34b, and the bush 42 allows the rod 3 to pass through.
6 is supported so as to be reciprocally movable in the vertical direction.

A spacer 50 is mounted on the peripheral surface of the rod 36 located in the negative pressure chamber 41, and the spacer 50 causes a predetermined volume between the diaphragm 35 and the sealing diaphragm 39, that is, the negative pressure chamber 41. It is supposed to be retained in the value.

A spring 44 is mounted between the diaphragm 35 and the sealing diaphragm 39, and the urging force of the spring 44 holds the diaphragm 35 at a predetermined position in the case 31 in a steady state.

A valve 37 connected to the other end (lower end) of the rod 36 has a cylindrical shape with its lower end closed.
The lower end has a flange portion 37 that projects radially outwardly in an annular shape.
a is integrally formed, and the peripheral edge portion on the upper surface side of the flange portion 37a is chamfered at a predetermined angle, and an annular valve portion 37b that can abut on a portion of the passage 46 through which exhaust gas flows.
Is formed.

The valve 37 is located in the substantially L-shaped flow passage 46 of the pipe joint 55, and is attached to an annular valve seat 47 mounted in an annular step portion 46a formed in a part of the flow passage 46. It moves from the direction of the flow to the direction of the front and contacts.

When the negative pressure is not supplied to the negative pressure chamber 41 of the exhaust gas recirculation control valve configured as described above, the diaphragm 35 causes the diaphragm 35 to move to a predetermined position in the case 31 by the urging force of the spring 44. The valve portion 37b of the valve 37, which is held by the valve 35 and is connected to the diaphragm 35 via the rod 36, comes into contact with the valve seat 47 of the flow path 46, the flow path 46 is closed, and the exhaust gas flows through the flow path 46. Is prevented from doing.

On the other hand, when negative pressure is supplied to the negative pressure chamber 41 from a pressure supply source (not shown), the diaphragm 35 is displaced downward against the biasing force of the spring 44, and
Following the displacement of the diaphragm 35, the rod 36 and the valve 37 integrally move downward, the valve portion 37b of the valve 37 is separated from the valve seat 47 of the flow path 46, and the flow path 46 is opened so that the flow path 46 is opened. Exhaust gas is allowed to flow through.

As described above, by supplying or stopping the supply of the negative pressure to the negative pressure chamber 41, a part of the flow path 46 through which the exhaust gas flows is opened or closed, and the recirculation of the exhaust gas is allowed or It will be blocked.

However, in the exhaust gas recirculation control valve as described above, the peripheral edge of the diaphragm 35 is sandwiched between the upper and lower cases 32 and 33, and the diaphragm 35 is held.
Since the atmospheric pressure chamber 40 is formed on the upper surface side of the and the negative pressure chamber 41 is formed on the lower surface side of the diaphragm 35,
It is necessary to seal the rod insertion portion of the lower case 33.

Therefore, the lower case 33 is replaced with the inner case 34a.
And an outer case 34b are formed in a double structure, and an inner case 34a is formed.
It is necessary to attach a sealing diaphragm 39 to the rod insertion portion of the above to seal the negative pressure chamber 41 and to attach a bush 42 to the rod insertion portion of the outer case 34b to support the rod 36 so as to be vertically reciprocable. There is. Further, in order to maintain a predetermined space between the diaphragm 35 and the sealing diaphragm 39, it is necessary to mount the spacer 50 on the peripheral surface of the rod 36. Therefore, the number of parts increases and the overall structure becomes complicated.

Further, since a part of the negative pressure chamber 41 is composed of the sealing diaphragm 39, a large force against the elastic force of the sealing diaphragm 39 is required to drive the rod 36. It is necessary to increase the size of the diaphragm 35, which increases the size of the whole.

The present invention solves the problems of the conventional ones described above, and reduces the number of parts to simplify the overall structure and reduce the size of the exhaust gas. It is intended to provide a recirculation control valve.

[0020]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a case including an upper case and a lower case, the case being provided in the case, and the inside of the case being a negative pressure chamber and an atmospheric pressure. A diaphragm that is divided into two chambers, a rod that is inserted through the lower case and one end of which is connected to the diaphragm, and a rod that is connected to the other end of the rod and that is located in a flow path through which exhaust gas flows. A means including a valve that opens and closes a part of the lever and a bush that is attached to the lower case and movably supports the rod is adopted. The lower case is equipped with a seal member that seals the insertion portion of the rod. The diaphragm is equipped with a seal member that seals the insertion portion of the rod, and the sealing member A means for forming a cooling portion for introducing outside air around the is adopted.

[0021]

The present invention, by adopting the above means,
In the state where the negative pressure is not supplied to the negative pressure chamber, the diaphragm is located at a predetermined position in the case, and the valve connected to the diaphragm via the rod blocks a part of the flow path through which the exhaust gas flows. The exhaust gas is prevented from flowing in the flow path. On the other hand, when negative pressure is supplied to the negative pressure chamber, the diaphragm is displaced and the rod and valve move integrally as the diaphragm moves, opening the part of the flow path through which the exhaust gas flows. However, the exhaust gas is allowed to flow in the flow path.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention shown in the drawings will be described below. FIG. 1 shows a first embodiment of an exhaust gas recirculation control valve according to the present invention. This exhaust gas recirculation control valve includes a case 1 composed of an upper case 2 and a lower case 3, and a case. 1, a diaphragm 5 that divides the inside of the case 1 into two chambers, an atmospheric pressure chamber 10 and a negative pressure chamber 11, and a central portion of the lower case 3 is inserted to connect one end to the central portion of the diaphragm 5. And a valve 7 that is connected to the other end of the rod 6 and that opens and closes a part of the flow path 16 through which exhaust gas flows.

The diaphragm 5 is made of an elastic material such as rubber and has a disk shape.
It is designed to be sandwiched between the peripheral edge of the lower case 3 and the peripheral edge of the lower case 3.

The upper case 2 has a tubular shape with its upper end closed, and a pipe member 8 for communicating the inside and outside of the upper case 2 is attached to the top of the upper case 2, and the upper case 2 is connected through this pipe member 8. The negative pressure chamber 11 formed between the inner surface of the diaphragm and the upper surface of the diaphragm 5 is connected to a pressure supply source (not shown).

The lower case 3 has a cylindrical shape with a closed lower end, and an opening 3 for communicating the inside and the outside with a side portion thereof.
a is provided, and the atmospheric pressure chamber 10 formed between the inner surface of the lower case 3 and the lower surface of the diaphragm 5 is opened to the atmosphere through the opening 3a.

The rod 6 is adapted to be inserted through the central portion of the closed portion of the lower case 3. Lower case 3
A bush 12 having a tubular shape is attached to the rod insertion portion of the rod 6, and the bush 12 supports the rod 6 so as to be capable of reciprocating in the vertical direction. 18 is bush 12
It is a packing that seals between the lower case 3 and the lower case 3.

An annular filter 13 is attached to the lower part of the bush 12, and the rod 6 is attached by the filter 13.
Impurities contained in the exhaust gas are prevented from entering between the bush 12 and the bush 12.

A spring 14 is mounted between the inner surface of the upper case 2 and the upper surface of the diaphragm 5, and the urging force of the spring 14 holds the diaphragm 5 at a predetermined position in the case 1 in a steady state. is there.

The center of the diaphragm 5 is sandwiched by a pair of retainers 15, 15 from above and below.
One end (upper end) of the rod 6 is connected to the center of the diaphragm 5 while penetrating the center of the diaphragm 5.

The valve 7 has a tubular shape with its upper end closed, and the rod 6 is provided at the central portion of the closed upper end.
The other end (lower end) of the is connected. A flange portion 7a, which projects annularly outward in the radial direction, is integrally provided at the upper end portion of the valve 7, and the peripheral edge portion on the lower surface side of the flange portion 7a is chamfered at a predetermined angle over the entire circumference. A valve portion 7b which can come into contact with a valve seat 17 described later is formed.

The valve 7 is provided in the flow passage 16 of the pipe joint 19 having a substantially L shape, and the valve portion 7b thereof is provided in the flow passage 16.
An annular valve seat 17 mounted in an annular stepped portion 16a provided in a part of the valve moves in the direction from the source of the flow to the abutting direction.

Next, the operation of the above-described device will be described. First, when the negative pressure is not supplied into the negative pressure chamber 11, the diaphragm 5 is held at a predetermined position in the case 1 by the urging force of the spring 14 and is connected to the diaphragm 5 via the rod 6. Valve part 7 of valve 7
b comes into contact with the valve seat 17 of the flow path 16, and the flow path 16 is closed to prevent exhaust gas from flowing through the flow path 16.

On the other hand, when a negative pressure is supplied to the negative pressure chamber 11 from a pressure supply source (not shown), the diaphragm 5 is displaced upward in the figure, and the displacement of the diaphragm 5 is followed so that the rod 6 and the valve 7 are integrated. Move to the upper part of the figure, valve 7
Of the flow path 16 is separated from the valve seat 17 of the flow path 16
Is opened and exhaust gas is allowed to flow in the flow path 16.

As described above, by supplying or stopping the supply of the negative pressure into the negative pressure chamber 11, the valve 7 connected to the diaphragm 5 via the rod 6 opens or closes the flow path 16 and exhausts the gas. Gas recirculation is allowed or blocked.

In the exhaust gas recirculation control valve according to this embodiment constructed as described above, the case 1 is divided into the negative pressure chamber 11 and the atmospheric pressure chamber 10 by the single diaphragm 5. Since the negative pressure chamber 11 is formed on the upper surface side of the diaphragm 5 and the atmospheric pressure chamber 10 is formed on the lower surface side of the diaphragm 5, a sealing diaphragm is used to seal the negative pressure chamber 11. Besides, it is not necessary to use a spacer to secure the volume of the negative pressure chamber 11. Therefore, the number of components can be significantly reduced, and the overall configuration can be simplified.

Further, since it is sufficient to displace one diaphragm 5 to drive the rod 6, the rod 6 can be driven without enlarging the diaphragm 5, and the overall size can be greatly reduced. Will be possible.

Further, since the atmospheric pressure chamber 10 is formed on the lower surface side of the diaphragm 5, the inside of the atmospheric pressure chamber 10 is opened to the atmosphere through the opening 3a provided on the side portion of the lower case 3. Even if high-temperature exhaust gas enters the lower case 3 through the space between the bush 12 and the rod 6, the cool air taken in through the opening 3a can sufficiently cool the lower case 3. Therefore, the diaphragm 5 is not heated and deteriorated by the high temperature exhaust gas,
The durability can be greatly increased.

FIG. 2 shows a second embodiment of the exhaust gas recirculation control valve according to the present invention. This exhaust gas recirculation control valve is provided at the center of the closed lower end of the lower case 3. A cylindrical projection 3b having a closed upper end is integrally provided, and the rod 6 is inserted into the center of the projection 3b, and an inner portion of the projection 3b has an annular shape that can abut the peripheral surface of the rod 6 at the center. Since the seal member 20 made of an elastic material such as annular rubber having the lip portion 20a is mounted, and the other structure is the same as that shown in the first embodiment, The same parts as those shown in the first embodiment are designated by the same reference numerals, and detailed description of the configuration will be omitted.

As in the case of the first embodiment, even in the case of this embodiment, when the negative pressure is not supplied into the negative pressure chamber 11, the urging force of the spring 14 causes The diaphragm 5 is held at a predetermined position in the case 1, and the valve portion 7b of the valve 7 connected to the diaphragm 5 via the rod 6 contacts the valve seat 17 of the flow passage 16 to close the flow passage 16. As a result, exhaust gas is prevented from flowing through the flow path 16.

On the other hand, when negative pressure is supplied to the negative pressure chamber 11 from a pressure supply source (not shown), the diaphragm 5 is displaced upward in the figure, and the rod 6 and the valve 7 follow the displacement of the diaphragm 5. The valve portion 7b of the valve 7 separates from the valve seat 17 of the flow passage 16 by moving integrally with the flow passage 1
6 is opened and exhaust gas is allowed to flow in the flow path 16.

As described above, by supplying or stopping the supply of the negative pressure into the negative pressure chamber 11, the valve 7 connected to the diaphragm 5 via the rod 6 opens or closes the flow path 16 and exhausts the gas. Gas recirculation is allowed or blocked.

Even in the exhaust gas recirculation control valve according to this embodiment configured as described above, as in the case of the first embodiment, the inside of the case 1 is formed by the single diaphragm 5 in the negative pressure chamber. 11 and atmospheric pressure chamber 10 are divided into two chambers,
Since the negative pressure chamber 11 is formed on the upper surface side of the diaphragm 5 and the atmospheric pressure chamber 10 is formed on the lower surface side of the diaphragm 5, a sealing diaphragm is not required to seal the negative pressure chamber 11. And the negative pressure chamber 11
It is not necessary to attach a spacer to the peripheral surface of the rod 6 to secure the volume of the above. Therefore, the number of constituent parts can be reduced, and the overall structure can be greatly simplified.

Further, since it is sufficient to displace one diaphragm 5 to drive the rod 6, the rod 6 can be driven without increasing the size of the diaphragm 5 and the overall size can be greatly reduced. You will be able to

Further, an atmospheric pressure chamber 10 is formed on the lower surface side of the diaphragm 5, and the inside of the atmospheric pressure chamber 10 is opened to the atmosphere through an opening 3a provided on a side portion of the lower case 3, and the lower end of the lower case 3 is opened. Providing a protrusion 3b on the inside of the rod 6
Since the seal member 20 having the lip portion 20a for sealing between the bush 12 and the rod 6 is mounted, even if exhaust gas enters between the bush 12 and the rod 6 into the protrusion 3b of the lower case 3, The exhaust gas is prevented from flowing into the diaphragm 5 side, and the diaphragm 5 is not exposed to the high temperature exhaust gas. Moreover, since the external cool air is taken into the lower case 3 through the opening 3a of the lower case 3, the seal member 20 can be effectively cooled through the protrusions 3b, and the deterioration of the seal member 20 due to heat is prevented. Therefore, the durability can be significantly increased.

FIG. 3 shows a third embodiment of the exhaust gas recirculation control valve according to the present invention. This exhaust gas recirculation control valve is provided at the center of the closed lower end of the lower case 3. A cylindrical protrusion 3b having a closed upper end is integrally provided, the rod 6 is inserted through the center of the protrusion 3, and the lower part of the pair of retainers 15, 15 that clamps the center of the diaphragm 5 from above and below. The annular seal member 21 having the lip portion 21a on the inner peripheral side is attached to the inner portion of the side retainer 15 and only when the diaphragm 5 is displaced downward, the inner peripheral side of the lip portion 21a surrounds the protrusion 3b. Since the other parts have the same structure as that shown in the first embodiment, the same parts as those shown in the first embodiment are The same number is attached to the structure A detailed description will be omitted.

As in the case of the first embodiment, when the negative pressure is not supplied to the negative pressure chamber 11, the force of the spring 14 exerts the same force as that of the first embodiment. The diaphragm 5 is held at a predetermined position in the case 1, and the valve portion 7b of the valve 7 connected to the diaphragm 5 via the rod 6 abuts on the valve seat 17 of the flow passage 16 to close the flow passage 16. As a result, exhaust gas is prevented from flowing through the flow path 16.

On the other hand, when negative pressure is supplied to the negative pressure chamber 11 from a pressure supply source (not shown), the diaphragm 5 is displaced upward in the figure, and the rod 6 and the valve 7 follow the displacement of the diaphragm 5. The valve portion 7b of the valve 7 separates from the valve seat 17 of the flow passage 16 by moving integrally with the flow passage 1
6 is opened and exhaust gas is allowed to flow in the flow path 16.

As described above, by supplying or stopping the supply of the negative pressure into the negative pressure chamber 11, the valve 7 connected to the diaphragm 5 via the rod 6 opens or closes the flow path 16 and exhausts the gas. Gas recirculation is allowed or blocked.

Even in the exhaust gas recirculation control valve according to this embodiment configured as described above, as in the case of the first embodiment, the inside of the case 1 is formed by the single diaphragm 5 in the negative pressure chamber. 11 and atmospheric pressure chamber 10 are divided into two chambers,
Since the negative pressure chamber 11 is formed on the upper surface side of the diaphragm 5 and the atmospheric pressure chamber 10 is formed on the lower surface side of the diaphragm 5, a sealing diaphragm is not required to seal the negative pressure chamber 11. And the negative pressure chamber 11
It is not necessary to mount a spacer on the peripheral surface of the rod 6 in order to secure the volume of the above. Therefore, the number of constituent parts can be reduced, and the overall structure can be greatly simplified.

Further, since it is sufficient to displace one diaphragm 5 to drive the rod 6, the rod 6 can be driven without enlarging the diaphragm 5 and the overall size can be greatly reduced. You will be able to

Further, an atmospheric pressure chamber 10 is formed on the lower surface side of the diaphragm 5, the inside of the atmospheric pressure chamber 10 is opened to the atmosphere through an opening 3a provided on the side portion of the lower case 3, and the central portion of the diaphragm 5 is opened. A pair of retainers 15 mounted on the
5, the seal member 21 is attached to the inner portion of the lower retainer 15 and the lip portion 21a is attached to the diaphragm 5
The bush 12 and the rod 6 are brought into contact with the peripheral surface of the protrusion 3b of the lower case 3 only when the lower case is displaced downward.
Even if the exhaust gas enters into the protrusion 3b from between, the seal member 21 prevents the exhaust gas from flowing into the diaphragm 5 side, and the diaphragm 5 is not exposed to the high temperature exhaust gas. Moreover, the opening 3 of the lower case 3
The cool air is taken into the lower case 3 from the outside from a, and the cool air is guided into the cooling portion 25 formed around the seal member 21, so that the seal portion of the seal member 21 can be effectively cooled. Therefore, the sealing member 21 is not deteriorated by the heat of the exhaust gas, and the durability can be significantly improved. When the valve 7 opens the flow path 16, the lip portion 2 of the seal member 21
1a is not in contact with the protrusion 3b of the lower case 3, but since the pressure in the flow path 16 is not high, there is almost no possibility that exhaust gas will enter the lower case 3 from between the bush 12 and the rod 6. is there.

Then, the lip portion 21a of the seal member 21.
Is the projection 3b only when the diaphragm 5 is displaced downward.
Since it comes into contact with the peripheral surface of the lip portion 21, the wear of the lip portion 21a can be minimized.

[0053]

The present invention has the following effects by being configured as in claim 1. That is,
Since it is sufficient to provide one diaphragm inside the case to divide the case into two chambers, a negative pressure chamber and an atmospheric pressure chamber, the number of components can be reduced and the overall configuration is greatly simplified. It will be possible to transform. Further, since it is sufficient to displace one diaphragm to move the rod, the rod can be driven without increasing the size of the diaphragm, and the overall size can be greatly reduced. Moreover, by having the structure as in claim 2, the same effect as that of claim 1 can be obtained, and the following effect can be obtained. That is, since the rod insertion portion of the lower case is sealed by the sealing member, it is possible to prevent the exhaust gas from acting on the diaphragm, and the diaphragm is exposed to the high temperature exhaust gas to promote deterioration. This will not happen and the durability will be greatly improved. Further, the structure as claimed in claim 3 provides the same effect as that of claim 1 and the following effect. That is, since the outside air is introduced into the cooling portion formed around the seal member attached to the diaphragm, the seal portion of the seal member can be effectively cooled. Therefore, the seal portion of the seal member can be prevented from being deteriorated by the heat of the exhaust gas, and the rod member of the lower case can be stably sealed for a long period of time by the seal member.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a first embodiment of an exhaust gas recirculation control valve according to the present invention.

FIG. 2 is a vertical sectional view showing a second embodiment of the exhaust gas recirculation control valve according to the present invention.

FIG. 3 is a vertical cross-sectional view showing a third embodiment of the exhaust gas recirculation control valve according to the present invention.

FIG. 4 is a longitudinal sectional view showing an example of a conventional exhaust gas recirculation control valve.

[Explanation of symbols]

 1, 31 ...... Case 2, 32 ...... Upper case 3, 33 ...... Lower case 3a ...... Aperture 3b ...... Projection 5, 35, 39 ...... Diaphragm 6,36 ...... Rod 7,37 ...... Valve 7a , 37a ... Flange portion 7b, 37b ... Valve portion 8, 38 ... Pipe member 10, 40 ... Atmospheric pressure chamber 11, 41 ... Negative pressure chamber 12, 42 ... Bushing 13 ... Filter 14, 44 ... ... Spring 15 ... Retainer 16, 46 ... Flow path 16a, 46a ... Step portion 17, 47 ... Valve seat 18 ... Packing 19, 55 ... Pipe joint 20, 21 ... Sealing member 20a, 21a ... Lip part 25 ...... Cooling part 32a ...... Hole 34a ...... Inner case 34b ...... Outer case 50 ...... Spacer

Claims (3)

[Claims] 1. A case (1) comprising an upper case (2) and a lower case (3), a case (1) provided in the case (1), and a negative pressure chamber (11) and an atmospheric pressure in the case (1). Room (1
0) a diaphragm (5) which is divided into two chambers, a rod (6) having one end connected to the diaphragm (5) through the lower case (3), and the other end of the rod (6). A valve (7) that is connected to the lower case (3) and is located in a flow path (16) through which exhaust gas flows and opens and closes a part of the valve (7) to move the rod (6). An exhaust gas recirculation control valve, characterized in that it comprises a bush (12) that supports the exhaust gas. 2. The exhaust gas recirculation control valve according to claim 1, wherein a seal member (20) for sealing the insertion portion of the rod (6) is attached to the lower case (3). 3. The diaphragm (5) is equipped with a seal member (21) for sealing the insertion part of the rod (6), and a cooling part (25) for introducing outside air around the seal member (21). The exhaust gas recirculation control valve according to claim 1, wherein