JP2015059530A - Exhaust gas recirculation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas recirculation device capable of reducing an EGR gas leakage flow rate during valve fully-closed time during which a valve element 10 fully closes an EGR passage 2.SOLUTION: An EGR valve 4 can restrict an abutment clearance 26a of a seal ring 26 from moving in a circular direction of a valve element 10 since an outer circumferential shape of the seal ring 26 is set to an elliptical shape and the seal ring 26 can be thereby whirl-stopped on a cylindrical nozzle 6. Furthermore, the seal ring 26 is arranged so that a long axis direction of the elliptical shape is set to an axial direction of the shaft 9 in a view from an axial center direction of the cylindrical nozzle 6, and the abutment clearance 26a is arranged in a direction in which the clearance is made smaller during valve fully-closed time, that is, in a direction in which the shaft 9 is inclined in response to a reaction of the spring 26. This can reduce an area of the abutment clearance 26a exposed from an outside diameter of the valve element 10 (a portion of the abutment clearance 26a protruding to an outside of the valve element 10 with respect to a circumferential groove 25) and, therefore, reduce an EGR gas leakage flow rate during the valve fully-closed time.

Description

  The present invention relates to an exhaust gas recirculation device provided in an exhaust gas recirculation passage for recirculating a part of exhaust gas discharged from an internal combustion engine to an intake side.

There exists patent document 1 as a prior art which concerns on an exhaust-gas recirculation apparatus.
The exhaust gas recirculation device includes a housing that forms an EGR passage, and an EGR valve that adjusts the flow rate of EGR gas that flows through the EGR passage.
As shown in FIG. 8, the EGR valve includes a shaft 100, a valve body 110 fixed to the end of the shaft 100, and the EGR passage and the valve body 110 when the valve body 110 fully closes the EGR passage. It is comprised with the seal ring 120 for plugging up the clearance gap produced between them.
The seal ring 120 is fitted into a circumferential groove 111 formed on the outer periphery of the valve body 110 with a joint gap 121 at one place in the circumferential direction, and movement in the circumferential direction is restricted by the following detent portion. ing. As shown in FIG. 9, the anti-rotation portion includes a pair of convex portions 122 provided at both ends of the seal ring 120 and a plane portion 112 formed in the circumferential groove 111 of the valve body 110. The convex part 122 abuts against the flat part 112 to prevent the seal ring 120 from rotating.

JP 2008-223505 A

By the way, in the EGR valve, since the valve body 110 is fixed to the end of the shaft 100 by welding, a shift occurs between the center of the EGR passage and the center of the valve body 110 due to the influence of welding distortion of the shaft 100.
Further, the EGR valve is biased in the valve closing direction by a spring, and the shaft 100 is inclined when the reaction force of the spring is applied to the end of the shaft 100. As a result, the valve body 110 fixed to the end portion of the shaft 100 is displaced in a direction in which the shaft 100 is inclined, so that a deviation occurs between the center of the EGR passage and the center of the valve body 110.
For this reason, when the valve body 110 fully closes the EGR passage, the gap generated between the outer periphery of the valve body 100 and the inner periphery of the EGR passage is not uniform over the entire periphery of the valve body 110. The gap is small when the center is shifted from the center of the EGR passage, and the gap is large on the opposite side.

However, the prior art of Patent Document 1 does not consider that the center of the valve body 110 is deviated from the center of the EGR passage, that is, the gap generated between the EGR passage and the valve body 110 is rotated in the direction of the smallest. There is no stop. In other words, since the anti-rotation portion is provided in the direction in which the gap is relatively large, the area of the joint gap 121 of the seal ring 120 located at the anti-rotation portion is increased. As a result, the EGR gas leakage flow rate when the valve is fully closed increases.
The present invention has been made to solve the above problems, and an object of the present invention is to provide an exhaust gas recirculation device capable of reducing the EGR gas leakage flow rate when the valve is fully closed.

  The present invention according to claim 1 is provided in an exhaust gas recirculation passage for returning a part of exhaust gas discharged from the internal combustion engine (hereinafter referred to as EGR gas) to the intake side of the internal combustion engine. A housing forming an EGR passage, an EGR valve for adjusting the flow rate of EGR gas flowing through the EGR passage, valve driving means for driving the EGR valve using a motor as a power source, and the EGR valve in the valve closing direction The EGR valve is rotatably supported by the housing via a bearing, and has one end projecting into the EGR passage and one end of the shaft fixed to the EGR valve. The valve body is arranged inside the EGR passage and rotates integrally with the shaft to change the opening area of the EGR passage, and is mounted in a circumferential groove formed on the entire outer periphery of the valve body. An exhaust gas recirculation device comprising a seal ring that closes a gap generated between the EGR passage and the valve body when the valve body is fully closed, and the seal ring has an elliptical outer peripheral shape. A seal ring from a linear direction (hereinafter referred to as the passage direction) perpendicular to the radial direction of the EGR passage, having a gap at one place in the circumferential direction intersecting the elliptical minor axis direction. The elliptical long axis direction is arranged in the axial direction of the shaft, and the abutment gap is arranged in the direction in which the shaft tilts in response to the reaction force of the spring when the valve is fully closed. At the end of the shaft with the valve body inclined at a predetermined angle with respect to the EGR passage so that the outer peripheral shape when the seal ring when the valve is fully closed is projected in the passage direction matches the inner peripheral shape of the EGR passage. Be fixed And butterflies.

In the invention according to claim 1, since the seal ring is prevented from rotating with respect to the EGR passage by making the outer peripheral shape of the seal ring elliptical, the joint gap of the seal ring moves in the circumferential direction of the valve body. Can be regulated. The seal ring is arranged such that the major axis direction of the ellipse is directed toward the axial direction of the shaft when viewed from the passage direction. Further, the valve body fixed to one end of the shaft is biased in the direction in which the shaft tilts due to the reaction force of the spring when the valve is fully closed. A gap generated between the outer periphery of the body is reduced.
On the other hand, the seal ring has an abutment gap formed at one place in the circumferential direction intersecting the elliptical minor axis direction, and the abutment gap is arranged in a direction in which the valve body is biased. That is, the abutment gap is arranged in the direction in which the gap between the valve body and the EGR passage is reduced. As a result, the area of the abutment gap exposed from the outer diameter of the valve body (abutment gap at the part protruding from the circumferential groove to the outside of the valve body) is reduced, thereby reducing the EGR gas leakage flow rate when the valve is fully closed. it can.

  The present invention according to claim 2 is provided in the exhaust gas recirculation passage for returning a part of exhaust gas (hereinafter referred to as EGR gas) discharged from the internal combustion engine to the intake side of the internal combustion engine. A housing forming an EGR passage, an EGR valve for adjusting the flow rate of EGR gas flowing through the EGR passage, valve driving means for driving the EGR valve using a motor as a power source, and the EGR valve in the valve closing direction The EGR valve is rotatably supported by the housing via a bearing, and has one end protruding into the EGR passage and a weld on one end of the shaft. And a valve body that is disposed inside the EGR passage and rotates integrally with the shaft to vary the opening area of the EGR passage, and a circumferential direction formed on the entire outer periphery of the valve body The exhaust gas recirculation device is provided with a seal ring that closes a gap generated between the EGR passage and the valve body when the valve body is fully closed. The entire circumferential shape of the bottom surface of the directional groove (hereinafter referred to as the groove bottom shape) is formed in an elliptical shape, and when the valve is fully closed, the shaft tilts in response to the reaction force of the spring, so that the center of the valve element is more The direction of deviation is defined as the X direction, the direction in which the center of the valve body deviates from the center of the EGR passage due to the welding distortion of the shaft is defined as the Y direction, and the half straight line rx extending in the X direction from the center of the valve body and the center of the valve body When the inferior angle sandwiched by the half straight line ry extending in the Y direction from the center is defined as the central angle α, the seal ring is provided in an elliptical shape in which the entire inner peripheral shape entering the circumferential groove corresponds to the groove bottom shape. Have a gap at one place in the circumferential direction, The abutment gap is arranged within the range of the central angle α.

In the invention according to claim 2, the seal ring is prevented from rotating by providing the groove bottom shape formed in the valve body as an ellipse and providing the inner peripheral shape of the seal ring as an ellipse corresponding to the groove bottom shape. Therefore, it can control that the joint gap of a seal ring moves to the peripheral direction of a valve body.
Moreover, the seal ring arrange | positions the joint gap in the range of center angle (alpha). The center angle α is a half straight line rx extending in the direction (X direction) in which the center of the valve body deviates from the center of the EGR passage due to the inclination of the shaft, and the direction in which the center of the valve body deviates from the center of the EGR passage due to welding distortion of the shaft ( It is an inferior angle sandwiched by a half straight line ry extending in the (Y direction). That is, it represents a range in which the valve body is biased due to the influence of the shaft inclination and welding distortion. Within this range (within the range of the central angle α), it occurs between the inner periphery of the EGR passage and the outer periphery of the valve body. The gap becomes smaller. Therefore, by arranging the seal ring joint gap within the range of the central angle α, the area of the joint gap exposed from the outer diameter of the valve body (the joint gap of the portion protruding from the circumferential groove to the outside of the valve body). Therefore, the leakage flow rate of EGR gas when the valve is fully closed can be reduced.

1 is a plan view of an EGR valve according to Embodiment 1. FIG. 1 is a cross-sectional view of an EGR device according to Embodiment 1. FIG. It is III-III sectional drawing of the EGR apparatus shown in FIG. It is an expanded sectional view which shows the site | part by which the seal ring was mounted | worn with the circumferential groove | channel of the valve body. It is a block diagram which feedback-controls the opening degree of an EGR valve by ECU. 6 is a plan view of a time EGR valve according to Embodiment 2. FIG. (A) It is a side view of the valve body which concerns on Example 3, (b) It is a side view of the 1st components and 2nd components which comprise a valve body. It is sectional drawing of the EGR valve disclosed by patent document 1. FIG. It is an enlarged view which shows the A section (rotation prevention part) of FIG.

  The mode for carrying out the present invention will be described in detail with reference to the following examples.

[Example 1]
The exhaust gas recirculation device of the present invention is arranged in an exhaust gas recirculation passage (not shown) for returning a part of exhaust gas (hereinafter referred to as EGR gas) discharged from the combustion chamber of the engine to the intake side of the engine. EGR device 1 is provided.
As shown in FIG. 2, the EGR device 1 includes a housing 3 that forms an EGR passage 2, an EGR valve 4 that adjusts the flow rate of EGR gas, valve drive means (described later) that drives the EGR valve 4, and EGR A spring 5 for urging the valve 4 in the valve closing direction, a rotation angle sensor (described later) for detecting the opening degree of the EGR valve 4 and the like are provided.

The housing 3 has an upstream end of the EGR passage 2 connected to the exhaust gas recirculation passage on the exhaust side, and a downstream end of the EGR passage 2 connected to the exhaust gas recirculation passage on the intake side. That is, the EGR passage 2 forms a part of the exhaust gas recirculation passage. As shown in FIG. 3, for example, a stainless steel cylindrical nozzle 6 is inserted into a part of the EGR passage 2.
The EGR valve 4 includes a shaft 9 that is rotatably supported by the housing 3 via two bearings 7 and 8, and a disc-shaped valve body 10 that is fixed to one end of the shaft 9. The valve body 10 rotates integrally with the shaft 9 to change the opening area of the EGR passage 2.
As specific examples of the bearings 7 and 8, in FIG. 2, a ball bearing is used as the bearing 7 and a sliding bearing is used as the bearing 8. Further, a seal member 11 for preventing leakage of EGR gas is disposed between the bearings 7 and 8.

The valve driving means includes a motor 12 that generates torque upon receipt of electric power, and a gear train that amplifies the driving torque of the motor 12 and transmits the amplified torque to the shaft 9.
The motor 12 is a DC motor, for example, and is accommodated in a motor chamber 13 (see FIG. 2) formed in the housing 3.
As shown in FIG. 2, the gear train includes a motor gear 14 attached to the output shaft of the motor 12, a valve gear 15 attached to the other end of the shaft 9, and an intermediate gear 16 that transmits the rotation of the motor gear 14 to the valve gear 15. , 17.
The intermediate gears 16 and 17 are composed of a large-diameter gear 16 that meshes with the motor gear 14 and a small-diameter gear 17 that meshes with the valve gear 15. Both the gears 16 and 17 are integrally formed on the same axis, and a common intermediate shaft is formed. 18 is rotatably supported.

The gear train is disposed in a gear chamber 19 formed on the upper end surface of the housing 3 in the figure, and is covered with a sensor cover 20.
The sensor cover 20 is, for example, a resin molded product, and is assembled to the end surface of the housing 3 where the gear chamber 19 is formed via a seal component 21 and is fixed to the housing 3 by tightening a screw or the like.
The spring 5 biases the EGR valve 4 to the fully closed position when the engine is stopped, that is, when the power supply to the motor 12 is stopped. Further, when the power supply to the motor 12 is interrupted due to some trouble during the operation of the engine 1, the EGR valve 4 can be returned to the fully closed position by the torque of the spring 5.

The rotation angle sensor is configured, for example, by arranging a Hall IC 23 inside a permanent magnet 22 mounted on the inner periphery of the valve gear 15. The Hall IC 23 outputs an electric signal (voltage) proportional to the magnetic flux density penetrating the Hall element to the ECU 24 (see FIG. 5) by rotating the permanent magnet 22 together with the valve gear 15.
As shown in FIG. 5, the ECU 24 calculates the target opening of the EGR valve 4 according to the operating state of the engine 1 grasped from the accelerator opening, the engine speed, etc., and detects the EGR valve 4 detected by the Hall IC 23. The power supplied to the motor 12 is feedback-controlled so that the actual opening of the motor coincides with the target opening.

Next, the configuration of the EGR valve 4 having the features of the present invention will be described in detail.
As shown in FIG. 4, the EGR valve 4 has a circumferential groove 25 formed on the outer peripheral surface of the valve body 10 over the entire circumference, and a seal ring 26 is attached to the circumferential groove 25. The seal ring 26 has a sealing function of closing a gap generated between the inner periphery of the cylindrical nozzle 6 and the outer periphery of the valve body 10 when the valve body 10 fully closes the EGR passage 2. The seal ring 26 is formed by bending a wire having a rectangular cross section made of a metal material such as stainless steel into an ellipse (see FIG. 1), and intersects the short axis direction (the left-right direction in the drawing) of the ellipse. A gap 26a is provided at one place in the circumferential direction. The abutment gap 26a refers to a gap formed between both ends of an elliptically bent wire, that is, between both ends facing in the circumferential direction.

  When viewed from the axial center direction of the cylindrical nozzle 6, the seal ring 26 according to the first embodiment is disposed with the major axis direction of the ellipse directed in the axial direction (the vertical direction in the drawing) of the shaft 9 as shown in FIG. 1. In addition, the abutment gap 26a is arranged in a direction (arrow direction in the drawing) in which the gap when the valve is fully closed is reduced. Note that the seal ring 26 shown in FIG. 1 is illustrated with an ellipse emphasized to clarify the shape, and is actually close to a circle with a smaller difference between the major axis and the minor axis than the ellipse shown in FIG. It is oval. Further, the axial direction of the cylindrical nozzle 6 refers to a linear direction orthogonal to the radial direction of the cylindrical nozzle 6 (straight line ZZ direction in FIGS. 3 and 4).

  By the way, in the EGR valve 4, the shaft 9 is slightly inclined by the reaction force of the spring 5 urging in the valve closing direction being applied to the other end of the shaft 9. Therefore, the valve body 10 that is cantilevered at one end of the shaft 9 is biased in the direction in which the shaft 9 is inclined inside the cylindrical nozzle 6, and therefore, between the center of the cylindrical nozzle 6 and the center of the valve body 10. Deviation occurs. Therefore, the gap generated between the outer periphery of the valve body 10 and the inner periphery of the cylindrical nozzle 6 when the valve is fully closed is not uniform over the entire periphery of the valve body 10, and the center of the valve body 10 is the center of the cylindrical nozzle 6. The gap is small in the direction of deviation, and the gap is large on the opposite side. Therefore, in the first embodiment, the joint gap 26a of the seal ring 26 is arranged in a direction in which the gap when the valve is fully closed is reduced, that is, in a direction in which the center of the valve body 10 is shifted from the center of the cylindrical nozzle 6 due to the inclination of the shaft 9. ing.

  Furthermore, the EGR valve 4 is axially oriented so that the outer peripheral shape when the seal ring 26 when the valve is fully closed is projected in the axial direction of the cylindrical nozzle 6 matches the inner peripheral shape (circular) of the cylindrical nozzle 6. On the other hand, the valve body 10 is fixed to the end of the shaft 9 in a state of being inclined at a predetermined angle θ. In other words, the outer peripheral shape (elliptical shape) of the seal ring 26 is a shape when obliquely cut at a predetermined angle θ with respect to the axial direction of the cylindrical nozzle 6, and the cylindrical nozzle 6 has a predetermined angle θ. The valve body 10 is fixed to the shaft 9 in a state where it is inclined with respect to the axial direction.

[Operation and Effect of Example 1]
In the EGR valve 4 according to the first embodiment, since the outer peripheral shape of the seal ring 26 is elliptical, the seal ring 26 is prevented from rotating with respect to the cylindrical nozzle 6. The movement in the circumferential direction can be restricted.
When viewed from the axial center direction of the cylindrical nozzle 6, the seal ring 26 is arranged so that the major axis direction of the ellipse is directed toward the axial direction of the shaft 9, and the gap when the valve is fully closed is reduced. A gap 26a is arranged. This reduces the area of the abutment gap 26a exposed from the outer diameter of the valve body 10 (the abutment gap 26a of the portion protruding to the outside of the valve body 10 from the circumferential groove 25), so that the EGR gas when the valve is fully closed Leakage flow rate can be reduced.

Hereinafter, other embodiments according to the present invention will be described.
In addition, what shows the component and structure which are common in Example 1 is provided with the same code | symbol as Example 1, and the detailed description is abbreviate | omitted.
[Example 2]
In the EGR valve 4 shown in the second embodiment, as shown in FIG. 6, the entire circumferential shape (hereinafter referred to as groove bottom shape) of the bottom surface of the circumferential groove 25 formed in the valve body 10 has an elliptical shape. The inner peripheral shape of the seal ring 26 is provided in an elliptical shape corresponding to the groove bottom shape. The outer peripheral shape of the seal ring 26 is circular. Further, the joint gap 26a of the seal ring 26 is disposed within the range of the central angle α described below.

The direction in which the center of the valve body 10 deviates from the center of the cylindrical nozzle 6 when the shaft 9 is tilted by the reaction force of the spring 5 when the valve is fully closed is defined as the X direction. A direction deviating from the center of the cylindrical nozzle 6 is defined as a Y direction.
A minor angle sandwiched between a half straight line rx extending from the center of the valve body 10 in the X direction and a half straight line ry extending from the center of the valve body 10 in the Y direction is defined as a central angle α.
In the EGR valve 4 of the present embodiment, the seal ring 26 is prevented from rotating by providing the inner peripheral shape of the seal ring 26 in an elliptical shape corresponding to the groove bottom shape. The movement in the 10 circumferential directions can be restricted.

  Further, the joint gap 26a of the seal ring 26 is disposed within the range of the central angle α. The central angle α represents a range in which the valve body 10 is biased due to the influence of the inclination of the shaft 9 and welding distortion. Within this range (within the range of the central angle α), the inner periphery of the cylindrical nozzle 6 and the valve body 10 are expressed. The gap generated between the outer periphery of the metal and the outer periphery becomes small. Therefore, by arranging the joint gap 26a of the seal ring 26 within the range of the central angle α, the joint gap 26a exposed from the outer diameter of the valve body 10 (the portion protruding from the circumferential groove 25 to the outside of the valve body 10). Therefore, the EGR gas leakage flow rate when the valve is fully closed can be reduced.

Example 3
The EGR valve 4 shown in the third embodiment is an example in which the valve body 10 is divided into at least two parts. For example, the valve body 10 shown in FIG. 7A is composed of two parts divided in the plate thickness direction (the left-right direction in the drawing).
Specifically, as shown in FIG. 5B, the first part 10a that forms one side surface 25a of the circumferential groove 25 and the other side surface 25b and bottom surface 25c of the circumferential groove 25 are formed. The valve body 10 having the circumferential groove 25 is formed by combining the two parts 10a and 10b. Note that the first component 10a and the second component 10b are formed by, for example, providing a positioning pin 10a1 integrally with the first component 10a and fitting it into a positioning hole 10b1 formed in the second component 10b. Misalignment between parts can be prevented.

In the third embodiment, since the first component 10a and the second component 10b can be respectively formed with a mold, the valve body 10 can be easily manufactured. In particular, as explained in the second embodiment, when the groove bottom shape of the circumferential groove 25 is formed in an elliptical shape, it is easier to make it with a die than by cutting, and as a result, the cost can be kept low. be able to.
In addition, although the example which divided | segmented the valve body 10 into 2 parts (1st part 10a and 2nd part 10b) was described in FIG. 7, it does not necessarily need to be 2 parts and it divides | segments into 3 parts or more. It can also be configured.

DESCRIPTION OF SYMBOLS 1 EGR apparatus 2 EGR channel | path 3 Housing 4 EGR valve 5 Spring 7 Bearing 8 Bearing 9 Shaft 10 Valve body 12 Motor (valve drive means)
14 Motor gear (valve drive means)
15 Valve gear (valve drive means)
16 Large diameter gear (valve drive means)
17 Small diameter gear (valve drive means)
25 Circumferential groove 26 Seal ring 26a Abutting gap

Claims (3)

An EGR passage which is disposed in an exhaust gas recirculation passage for returning a part of exhaust gas discharged from the internal combustion engine (hereinafter referred to as EGR gas) to the intake side of the internal combustion engine and forms a part of the exhaust gas recirculation passage A housing (3) forming (2);
An EGR valve (4) for adjusting the flow rate of EGR gas flowing through the EGR passage (2);
Valve driving means for driving the EGR valve (4) using a motor (12) as a power source;
A spring (5) for urging the EGR valve (4) in the valve closing direction;
The EGR valve (4)
A shaft (9) that is rotatably supported by the housing (3) via a bearing and has one end protruding into the EGR passage (2);
A valve which is fixed to one end of the shaft (9) and is disposed inside the EGR passage (2), and rotates integrally with the shaft (9) to vary the opening area of the EGR passage (2). Body (10);
The EGR passage (25) is attached to a circumferential groove (25) formed on the entire outer periphery of the valve body (10) so that the valve body (10) fully closes the EGR passage (2). 2) an exhaust gas recirculation device comprising a seal ring (26) for closing a gap formed between the valve body (10) and
The seal ring (26) has an outer peripheral shape that is elliptical, and has an abutment gap (26a) at one location in the circumferential direction that intersects the minor axis direction of the elliptical shape, and the EGR passage (2) When the seal ring (26) is viewed from a linear direction perpendicular to the radial direction (hereinafter referred to as a passage direction), the elliptical long axis direction is disposed toward the axial direction of the shaft (9), In addition, the joint gap (26a) is disposed in a direction in which the shaft (9) is inclined by receiving a reaction force of the spring (5) when the valve is fully closed.
The EGR valve (4) is configured so that the outer peripheral shape when the seal ring (26) when the valve is fully closed is projected in the passage direction matches the inner peripheral shape of the EGR passage (2). An exhaust gas recirculation device characterized in that the valve element (10) is fixed to the end of the shaft (9) in a state of being inclined at a predetermined angle with respect to the passage (2). An EGR passage which is disposed in an exhaust gas recirculation passage for returning a part of exhaust gas discharged from the internal combustion engine (hereinafter referred to as EGR gas) to the intake side of the internal combustion engine and forms a part of the exhaust gas recirculation passage A housing (3) forming (2);
An EGR valve (4) for adjusting the flow rate of EGR gas flowing through the EGR passage (2);
Valve driving means for driving the EGR valve (4) using a motor (12) as a power source;
A spring (5) for urging the EGR valve (4) in the valve closing direction;
The EGR valve (4)
A shaft (9) that is rotatably supported by the housing (3) via a bearing and has one end protruding into the EGR passage (2);
The shaft (9) is fixed to one end of the shaft by welding and disposed inside the EGR passage (2), and rotates integrally with the shaft (9) to change the opening area of the EGR passage (2). A valve body (10) to
The EGR passage (25) is attached to a circumferential groove (25) formed on the entire outer periphery of the valve body (10) so that the valve body (10) fully closes the EGR passage (2). 2) an exhaust gas recirculation device comprising a seal ring (26) for closing a gap formed between the valve body (10) and
In the valve body (10), the entire circumferential shape of the bottom surface of the circumferential groove (25) (hereinafter referred to as the groove bottom shape) is formed in an elliptical shape.
The direction in which the center of the valve body (10) is displaced from the center of the EGR passage (2) when the shaft (9) is tilted by the reaction force of the spring (5) when the valve is fully closed is defined as the X direction. And
A direction in which the center of the valve body (10) is displaced from the center of the EGR passage (2) due to welding distortion of the shaft (9) is defined as a Y direction,
When an inferior angle between a half line rx extending in the X direction from the center of the valve body (10) and a half line ry extending in the Y direction from the center of the valve body (10) is defined as a center angle α,
The seal ring (26) is provided in an elliptical shape in which the entire inner circumferential shape entering the circumferential groove (25) corresponds to the groove bottom shape, and an abutment gap (26a) is provided at one place in the circumferential direction. ), And the joint gap (26a) is arranged within the range of the central angle α. The exhaust gas recirculation device according to claim 1 or 2,
The valve body (10) is divided into at least two parts (10a, 10b), and the circumferential groove (25) is formed by combining the two parts (10a, 10b). Exhaust gas recirculation device.

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