JP2018080584A - Exhaust recirculation valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent corrosion caused by condensation water in part of a housing forming a bag space on a flow passage side of a seal member in an EGR valve.SOLUTION: An EGR valve 1 includes: a valve housing 10A having a flow passage 6; a valve seat 7 disposed in the flow passage 6 and including a valve hole 7a; a valve element 8 provided in the flow passage 6 so as to enable seating on the valve seat 7; a rotating shaft 9 rotated to open/close the valve element 8 relative to the valve seat 7; bearings 11, 12 for rotatably supporting the rotating shaft 9 in the valve housing 10A; a lip seal 13 provided between the rotating shaft 9 and the valve housing 10A between the flow passage 6 and the bearing 12 and comprising an elastic body; and a bag space 16 formed between the flow passage 6 and the lip seal 13. The EGR valve 1 is disposed so that the rotating shaft 9 extends horizontally while mounted on a vehicle. The valve housing 10A includes a water vent passage 17 communicated with the flow passage 6 from the bag space 16, corresponding to a lowest section of the bag space 16.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an exhaust gas recirculation valve provided in an engine system for adjusting the flow rate of exhaust gas recirculation gas flowing through an exhaust gas recirculation passage.

  Conventionally, as this kind of technology, for example, an exhaust gas recirculation valve (EGR valve) including a double eccentric valve described in Patent Document 1 below is known. This double eccentric valve is configured to improve the sealing performance when fully closed and to prevent wear due to drag between the valve body and the valve seat when the valve body rotates. That is, the double eccentric valve has a valve seat including a valve hole and a seat surface formed at an edge of the valve hole, a valve body having a seal surface corresponding to the seat surface formed on the outer periphery, and the valve body is rotated. A rotating shaft to be driven, a drive mechanism for rotating the rotating shaft, and a bearing for supporting the rotating shaft. The valve seat and the valve body are disposed in a flow path formed in the valve housing. The flow path is divided into an upstream flow path and a downstream flow path with respect to the fluid flow with the valve seat as a boundary, and the valve element is disposed in the upstream flow path.

  Here, in FIG. 9, a part of EGR valve is shown with sectional drawing. Adjacent to the flow path 51, a rubber lip seal 54 is provided between the rotary shaft 52 and the valve housing 53. The lip seal 54 is separated from the flow path 51 by a deposit guard 55 formed in a part of the valve housing 53 on the flow path 51 side from the lip seal 54. The deposit guard 55 prevents the deposit from entering the lip seal 54 side from the flow path 51. A gap 56 is formed between the rotating shaft 52 and the deposit guard 55 to prevent the deposit from entering and allow the rotating shaft 52 to rotate. In the valve housing 53, a bag space 57 having a gap 56 as an inlet is formed between the deposit guard 55 and the lip seal 54. Here, the rotating shaft 52 can be formed of SUS, and the valve housing 53 can be formed of aluminum. In FIG. 9, “58” indicates a part of the valve seat provided in the flow path 51, and “59” indicates a part of the valve body fixed to the distal end portion of the rotating shaft 52.

International Publication No. 2016/002599

  By the way, in the EGR valve of patent document 1, as shown in FIG. 9, the case where an EGR valve is arrange | positioned and used for a motor vehicle so that the rotating shaft 52 may extend horizontally can be assumed. For this reason, for example, when EGR gas enters the bag space 57 from the flow path 51 through the gap 56 when the engine is started at a low temperature, condensed water is generated in the bag space 57, and the condensed water is not discharged and the bag space is discharged. 57 may remain. If this condensed water is strongly oxidized, corrosion may occur and progress in the portion of the valve housing 53 forming the bag space 57, and the sealing function of the lip seal 54 may be impaired.

  The present invention has been made in view of the above circumstances, and an object thereof is to prevent the occurrence of corrosion due to condensed water in a part of the housing that forms the bag space on the flow path side from the seal member. An exhaust recirculation valve is provided.

  In order to achieve the above object, an invention according to claim 1 includes a housing including a flow path through which exhaust gas recirculation gas flows, a valve seat disposed in the flow path and including a valve hole, and a valve seat in the flow path. A valve body provided so as to be seated; a rotary shaft that is rotated to open and close the valve body with respect to the valve seat; a bearing that rotatably supports the rotary shaft in the housing; a flow path and a bearing; A seal member made of an elastic body provided between the rotary shaft and the housing, and a bag space formed between the rotary shaft and the housing between the flow path and the seal member, In the exhaust gas recirculation valve configured to open the valve body by rotating the rotation shaft from the fully closed state where the valve body is seated on the valve seat, the exhaust recirculation valve is configured so that the rotation shaft is horizontal when mounted on the vehicle. The housing is arranged to extend at least at the bottom of the bag space And response, and the spirit of the drain passage communicating from the bag space to the flow path is provided.

  According to the configuration of the present invention, even if condensed water is generated in the bag space of the housing, the condensed water is removed from the bag space via the drain passage provided corresponding to at least the lowermost portion of the bag space. It is discharged to the flow path. Therefore, the condensed water remaining in the bag space is reduced. Even if the minute oxide in the condensed water remains in the bag space, the minute oxide is diluted by the condensed water generated in the bag space and is discharged to the flow path through the drain passage.

  To achieve the above object, according to a second aspect of the present invention, in the first aspect of the present invention, the housing is continuous with the first inner wall portion between the flow path and the seal member, and the first inner wall portion. And a rust preventive film is formed on the first inner wall portion and at least a part of the second inner wall portion on the flow path side. The purpose.

  According to the configuration of the invention, in addition to the action of the invention according to claim 1, a rust-proof coating is formed on the first inner wall portion and at least a part of the second inner wall portion on the flow path side. Even if a minute oxide remains in the bag space, corrosion of the first inner wall portion is suppressed by the rust preventive coating. Moreover, the penetration | invasion of the condensed water from a bag space between a sealing member and a 2nd inner wall part is suppressed by a rust preventive film.

  In order to achieve the above object, according to a third aspect of the present invention, in the second aspect of the present invention, the tip portion of the anticorrosive coating, which is a portion where the radial outer peripheral surface of the seal member contacts is tapered. The purpose is to be formed.

  According to the configuration of the above invention, in addition to the action of the invention according to claim 2, when the seal member is assembled between the rotary shaft and the housing, the seal is prevented from the tip of the anticorrosive film formed on the second inner wall portion. The member is moved in the direction of the antirust coating. Since the front-end | tip part of a rust preventive film makes a taper at this time, the radial direction outer peripheral surface of a sealing member moves toward the rust preventive film smoothly.

  In order to achieve the above object, the invention according to claim 4 is the invention according to claim 2 or 3, wherein the rust preventive film is formed of a resin material.

  According to the configuration of the above invention, in addition to the action of the invention according to claim 2 or 3, since the rust preventive film is formed of the resin material, it is applied to the second inner wall portion for forming the rust preventive film. Material application becomes easy.

  In order to achieve the above object, the invention according to claim 5 is the invention according to any one of claims 2 to 4, wherein in the bag space, the rotation shaft is disposed between the rotation shaft and the first inner wall portion. The purpose is to provide blades that rotate integrally.

  According to the configuration of the above invention, in addition to the operation of the invention according to any one of claims 2 to 4, when opening and closing the valve body, the blade rotates together with the rotation shaft, and the blade slides on the first inner wall portion. As a result, the carbon adhering to the first inner wall is swept down into the bag space.

  According to the first aspect of the present invention, it is possible to prevent the occurrence of corrosion due to condensed water in a part of the housing that forms the bag space on the flow path side from the seal member.

  According to invention of Claim 2, in addition to the effect of invention of Claim 1, the 1st inner wall part which forms bag space, and the 2nd inner wall part 19 which the radial direction outer peripheral surface of a seal member contacts, , The occurrence of corrosion due to condensed water can be prevented. In addition, it is possible to prevent the seal member from being displaced between the rotating shaft and the housing.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 2, the assembling property of the seal member between the rotating shaft and the housing can be improved.

  According to the invention described in claim 4, in addition to the effect of the invention described in claim 2 or 3, the formation of the rust preventive film on the second inner wall portion can be facilitated.

  According to the invention described in claim 5, in addition to the effect of the invention described in any one of claims 2 to 4, carbon deposition in the bag space can be prevented.

The longitudinal cross-sectional view which concerns on 1st Embodiment and shows an EGR valve. The expanded sectional view which concerns on 1st Embodiment and shows the inside of the dashed-dotted line square of FIG. The AA sectional view taken on the line of FIG. 2 which shows an EGR valve according to the first embodiment. The expanded sectional view according to FIG. 2 which concerns on 2nd Embodiment and shows a part of EGR valve. Sectional drawing which concerns on 3rd Embodiment and shows a part of EGR valve. The expanded sectional view which concerns on 3rd Embodiment and shows the inside of the dashed-dotted line square of FIG. An expanded sectional view showing a part of EGR valve concerning a 4th embodiment. The BB sectional drawing of FIG. 7 which concerns on 4th Embodiment and shows an EGR valve. Sectional drawing which concerns on a prior art example and shows a part of EGR valve.

<First Embodiment>
Hereinafter, a first embodiment in which an exhaust gas recirculation valve of the present invention is embodied in an automobile gasoline engine system will be described in detail with reference to the drawings.

  FIG. 1 is a longitudinal sectional view of an exhaust gas recirculation valve (EGR valve) 1. FIG. 1 shows an arrangement state of an EGR valve 1 provided in an encoper of an automobile, in which the upper side shows the sky and the lower side shows the ground. The EGR valve 1 has a flow rate of EGR gas in an exhaust gas recirculation passage (EGR passage) in which a part of the exhaust gas discharged from the engine to the exhaust passage flows as an exhaust gas recirculation gas (EGR gas) to the intake passage and is recirculated to the engine. Provided to adjust.

  In this embodiment, the EGR valve 1 is constituted by an electric valve having a variable opening. The EGR valve 1 desirably has characteristics of large flow rate, high response, and high resolution. Therefore, in this embodiment, as a structure of the EGR valve 1, for example, a “double eccentric valve” described in Japanese Patent No. 5759646 can be adopted as a basic configuration. This double eccentric valve is configured for large flow control.

  The EGR valve 1 includes a valve portion 2 constituted by a double eccentric valve, a motor portion (not shown) incorporating a motor, and a speed reduction mechanism portion 3 including a plurality of gears. The valve unit 2 includes a flow path 6 through which EGR gas flows. In the flow path 6, the valve seat 7, the valve body 8, and the distal end portions of the rotary shaft 9 are disposed. The rotational force of the motor is transmitted to the rotation shaft 9 via the speed reduction mechanism unit 3.

  FIG. 1 shows a fully closed state in which the valve body 8 is seated on the valve seat 7. A valve seat 7 is incorporated in the step portion 6 a of the flow path 6. The valve seat 7 has an annular shape and has a valve hole 7a in the center. The valve body 8 has a disc shape and is provided so as to be seated on the valve seat 7. The valve body 8 is fixed to the tip of the rotating shaft 9. The rotating shaft 9 is rotated to open and close the valve body 8 with respect to the valve seat 7. In FIG. 1, the flow path 6 is divided into an upstream flow path 6 </ b> A and a downstream flow path 6 </ b> B in the flow of EGR gas, with the valve seat 7 as a boundary. In this embodiment, below the valve seat 7 shows the upstream flow path 6A, and above the valve seat 7 shows the downstream flow path 6B. The valve body 8 and the rotating shaft 9 are disposed in the upstream flow path 6A. The upstream flow path 6A is connected to the exhaust passage through the EGR passage. The downstream channel 6B is connected to the intake passage via the EGR passage.

  As shown in FIG. 1, the EGR valve 1 includes a housing 10 as a main component in addition to the valve seat 7, the valve body 8 and the rotating shaft 9. The housing 10 includes an aluminum valve housing 10A including the valve portion 2 and the like, and a synthetic resin end frame 10B that closes an opening end of the valve housing 10A. The valve seat 7, the valve body 8, and the rotating shaft 9 are provided in the valve housing 10A. The valve body 8 is fixed to a pin 9 a at the tip which is the free end of the rotating shaft 9. The rotating shaft 9 has a base end portion 9b on the opposite side of the pin 9a, and is cantilevered by the valve housing 10A at the base end portion 9b. The base end portion 9b of the rotating shaft 9 is rotatably supported by the valve housing 10A via a first bearing 11 and a second bearing 12 that are disposed apart from each other. The second bearing 12 is disposed closer to the flow path 6 than the first bearing 11. In this embodiment, detailed description of the motor unit, the speed reduction mechanism unit 3 and the like is omitted.

  Therefore, as shown in FIG. 1, when the rotating shaft 9 is rotated (forward rotation) from the fully closed state where the valve body 8 is seated on the valve seat 7, the valve body 8 is rotated together with the rotating shaft 9, and the valve The valve body 8 opens the seat 7. On the other hand, by rotating the rotating shaft 9 in the reverse direction from the valve body 8 opened, the valve body 8 rotates in the reverse direction together with the rotating shaft 9, and the valve body 8 is closed with respect to the valve seat 7.

  FIG. 2 is an enlarged cross-sectional view showing the inside of the chain line square S1 of FIG. FIG. 3 shows the EGR valve 1 by a cross-sectional view taken along line AA of FIG. As shown in FIG. 1, the EGR valve 1 is arranged so that the rotating shaft 9 extends horizontally when mounted on an automobile. As shown in FIGS. 1 to 3, a lip seal 13 made of an elastic body is provided between the flow path 6 and the second bearing 12 and between the rotary shaft 9 and the valve housing 10 </ b> A. General rubbers (elastomers) such as natural rubber or synthetic rubber can be used for the elastic body. The lip seal 13 corresponds to an example of a seal member of the present invention. The lip seal 13 is separated from the flow path 6 with a deposition guard 14 formed in the valve housing 10 </ b> A adjacent to the flow path 6. Due to the presence of the deposit guard 14, the intrusion of deposit from the flow path 6 to the lip seal 13 side is suppressed. A gap 15 is formed between the rotating shaft 9 and the deposit guard 14 so as to restrict the intrusion of deposit and allow the rotating shaft 9 to rotate. Further, in the valve housing 10A, a bag space 16 having a gap 15 as an inlet is formed between the deposition guard 14 and the lip seal 13 between the rotary shaft 9 and the valve housing 10A. In this embodiment, the rotating shaft 9 is made of SUS, and the valve housing 10A is made of aluminum.

  Here, when the EGR gas enters the bag space 16 from the upstream flow path 6A through the gap 15 when the engine is started at a low temperature, condensed water is generated in the bag space 16, and the condensed water is not discharged and the bag space is discharged. 16 may remain. If this condensed water is strongly oxidized, corrosion may occur and proceed at the portion of the valve housing 10A forming the bag space 16, and the sealing function of the lip seal 13 may be impaired. Therefore, the EGR valve 1 of this embodiment includes the following corrosion prevention structure.

  As shown in FIGS. 2 and 3, the corrosion prevention structure of this embodiment includes a drainage passage 17 formed in the deposit guard 14 in a hole shape. The drainage passage 17 is formed in the deposit guard 14 between the upstream flow path 6 </ b> A and the bag space 16 so as to correspond to the lowermost part of the bag space 16. The drainage passage 17 communicates from the bag space 16 to the upstream flow path 6A.

  According to the configuration of the EGR valve 1 of this embodiment described above, even if condensed water is generated in the bag space 16 of the valve housing 10 </ b> A, the condensed water is drained at the bottom of the bag space 16. It is discharged from the bag space 16 through the passage 17 to the upstream flow path 6A. Therefore, the condensed water remaining in the bag space 16 is reduced. Even if the minute oxide in the condensed water remains in the bag space 16, the minute oxide is diluted by the condensed water generated in the bag space 16 next, and the upstream flow path 6 </ b> A is passed through the drain passage 17. Is discharged. For this reason, generation | occurrence | production of the corrosion by condensed water can be prevented in a part of valve housing 10A which forms the bag space 16 on the flow path 6 side from the lip seal 13.

Second Embodiment
Next, a second embodiment in which the EGR valve of the present invention is embodied in an automobile gasoline engine system will be described in detail with reference to the drawings.

  In the following description, components equivalent to those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described. This embodiment is different from the first embodiment in terms of the corrosion prevention structure.

  In this embodiment, an EGR passage in which the EGR valve 1 is provided is assumed to have a type in which its inlet is connected to an exhaust passage downstream of the catalyst. The deposit hardly penetrates into this type of EGR passage, and the deposit hardly flows into the flow path 6 of the EGR valve 1. Therefore, in the EGR valve 1 of this embodiment, the deposit guard that separates the upstream flow path 6A and the bag space 16 is omitted.

  4 shows a part of the EGR valve 1 in an enlarged cross-sectional view similar to FIG. As shown in FIG. 4, in this embodiment, a portion adjacent to the flow path 6 of the valve housing 10 </ b> A is a drainage passage 17 corresponding to the entire circumference of the rotating shaft 9. In addition, the valve housing 10 </ b> A is continuous with the first inner wall portion 18 (inner wall portion in a range indicated by E <b> 1 in FIG. 4) between the flow path 6 and the lip seal 13 and the lip seal 13. 2nd inner wall part 19 (inner wall part of the range shown by E2 in FIG. 4) which the radial direction outer peripheral surface 13a contacts. A rust preventive coating 20 is formed on most of the first inner wall portion 18 and a part of the second inner wall portion 19 on the flow path 6 side. This rust preventive coating 20 is formed of a resin material. In this embodiment, a material such as Teflon (registered trademark) coat or epoxy (cation) is used as the resin material. The rust preventive coating 20 can be formed by applying these materials to the first inner wall portion 18 and the second inner wall portion 19 and baking them.

  However, since the anticorrosive film 20 formed of a resin material such as Teflon coat or epoxy has a relatively small coefficient of friction, when the lip seal 13 is assembled, the anticorrosive film 20 between the lip seal 13 and the anticorrosive film 20 There is a possibility that slipping occurs and the lip seal 13 is displaced. Therefore, in this embodiment, the portion of the outer peripheral surface 13a in the radial direction of the lip seal 13 that is in contact with the rust preventive coating 20 is a half of the outer peripheral surface 13a on the flow path 6 side, and the second outer peripheral surface 13a. The half of the bearing 12 is in direct contact with the second inner wall portion 19.

  In FIG. 4, a convex portion 21 that narrows the drainage passage 17 is provided above the rotation shaft 9 and between the valve seat 7 and the bag space 16. The convex portion 21 prevents the lip seal 13 from coming out to the upstream flow path 6A.

  According to the configuration of the EGR valve 1 of this embodiment described above, the condensed water generated in the bag space 16 is discharged from the bag space 16 to the upstream flow path 6A via the drainage passage 17, so that the first implementation Actions and effects equivalent to the form can be obtained. In addition, according to the configuration of this embodiment, the anticorrosive coating 20 is formed on the first inner wall portion 18 and at least a part of the second inner wall portion 19 on the flow path 6 side. Even if the minute oxide remains, the corrosion of the first inner wall portion 18 is suppressed by the rust preventive coating 20. Further, the entry of condensed water from the bag space 16 between the lip seal 13 and the second inner wall portion 19 is suppressed by the rust preventive coating 20. For this reason, generation | occurrence | production of the corrosion by condensed water can be prevented in the 1st inner wall part 18 which forms the bag space 16, and the 2nd inner wall part 19 which the radial direction outer peripheral surface 13a of the lip seal 13 contacts. Further, a part of the outer peripheral surface 13a in the radial direction of the lip seal 13 is in direct contact with the second inner wall portion 19 having a relatively large friction coefficient instead of the antirust coating 20. For this reason, the position shift of the lip seal 13 can be prevented between the rotating shaft 9 and the valve housing 10A.

  Further, according to the configuration of this embodiment, since the rust preventive coating 20 is formed of a resin material, it is easy to apply the material onto the second inner wall portion 19 for forming the rust preventive coating 20. For this reason, formation of the antirust coating 20 on the second inner wall portion 19 can be facilitated.

<Third Embodiment>
Next, a third embodiment in which the EGR valve of the present invention is embodied in an automobile gasoline engine system will be described in detail with reference to the drawings.

  This embodiment is different from the second embodiment in terms of the corrosion prevention structure. FIG. 5 is a sectional view showing a part of the EGR valve 1. FIG. 6 is an enlarged cross-sectional view showing the inside of the chain line square S2 of FIG. As shown in FIGS. 5 and 6, in this embodiment, the tip portion 20 a of the rust preventive coating 20 that is in contact with the radially outer peripheral surface 13 a of the lip seal 13 is tapered. Here, as shown in FIG. 6, the thickness α of the antirust coating 20 can be set to about “20 μm”.

  Therefore, according to the configuration of this embodiment, in addition to the operations and effects of the second embodiment, the following operations and effects can be obtained. That is, when the lip seal 13 is assembled between the rotary shaft 9 and the valve housing 10A, the lip seal 13 is moved in the direction of the rust preventive coating 20 from the tip portion of the rust preventive coating 20 formed on the second inner wall portion 19. . At this time, since the tip portion 20a of the rust preventive coating 20 is tapered, the radially outer peripheral surface 13a of the lip seal 13 moves smoothly toward the rust preventive coating 20. For this reason, the assembling property of the lip seal 13 between the rotating shaft 9 and the valve housing 10A can be improved.

<Fourth embodiment>
Next, a fourth embodiment in which the EGR valve of the present invention is embodied in an automobile gasoline engine system will be described in detail with reference to the drawings.

  This embodiment is different from the second embodiment in terms of the corrosion prevention structure. FIG. 7 shows a part of the EGR valve 1 in an enlarged sectional view. FIG. 8 shows the EGR valve 1 by a sectional view taken along line BB in FIG. As shown in FIGS. 7 and 8, in this embodiment, in the bag space 16, the rotating shaft 9 rotates integrally with the rotating shaft 9 between the antirust coating 20 formed on the first inner wall portion 18 and the rotating shaft 9. A blade 22 is provided. As shown in FIG. 8, the blade 22 includes four blades 22 a arranged at equiangular intervals around the rotation shaft 9, and the outer periphery of the blade 22 a is provided so as to be in contact with the anticorrosive coating 20. The blades 22 rotate integrally with the rotary shaft 9 in order to discharge carbon that is about to enter the bag space 16 and condensed water generated in the bag space 16 from the upstream channel 6A. .

  Therefore, according to the configuration of this embodiment, in addition to the operations and effects of the second embodiment, the following operations and effects can be obtained. That is, in the EGR valve 1, when the valve body 8 is opened and closed, the blade 22 rotates together with the rotating shaft 9, and the blade 22 is slidably contacted with the first inner wall portion 18, thereby attaching to the first inner wall portion 18. Carbon is swept into the bag space 16. Further, the carbon that has been swept down into the bag space 16 is discharged to the upstream flow path 6 </ b> A through the drainage passage 17. For this reason, accumulation of carbon in the bag space 16 can be prevented.

  The present invention is not limited to the above-described embodiments, and a part of the configuration can be changed as appropriate without departing from the spirit of the invention.

  (1) In the second to fourth embodiments, the deposition guard 14 is omitted from between the flow path 6 and the bag space 16, but the deposition guard is provided in the configuration of the second to fourth embodiments, and the hole A water drainage passage may be provided.

  (2) In the fourth embodiment, by sweeping the blade 22 a of the blade 22, the carbon that is swept away can be guided toward the drainage passage 17.

  (3) In the second to fourth embodiments, a part of the radial outer peripheral surface 13a of the lip seal 13 is provided so as to contact the rust preventive coating 20, but the entire radial outer peripheral surface of the lip seal is used. It can also be provided so as to be in contact with the anticorrosive coating.

  The present invention can be used for an exhaust gas recirculation device (EGR device) provided in an engine.

1 EGR valve (exhaust gas recirculation valve)
6 Flow path 6A Upstream flow path 7 Valve seat 7a Valve hole 8 Valve body 9 Rotating shaft 10 Housing 10A Valve housing 11 First bearing 12 Second bearing 13 Lip seal (seal member)
13a Radial outer peripheral surface 14 Depot guard 15 Gap 16 Bag space 17 Drain passage 18 First inner wall portion 19 Second inner wall portion 20 Anticorrosive coating 20a Tip portion 21 Convex portion 22 Blade

Claims (5)

A housing including a flow path through which exhaust recirculation gas flows;
A valve seat disposed in the flow path and including a valve hole;
A valve body provided so as to be seated on the valve seat in the flow path;
A rotating shaft that is rotated to open and close the valve body with respect to the valve seat;
A bearing for rotatably supporting the rotating shaft in the housing;
A seal member made of an elastic body provided between the rotating shaft and the housing between the flow path and the bearing;
A bag space formed between the rotary shaft and the housing is provided between the flow path and the seal member, and the rotary shaft is rotated from a fully closed state where the valve body is seated on the valve seat. In the exhaust gas recirculation valve configured to open the valve body by causing
The exhaust gas recirculation valve is arranged so that the rotating shaft extends horizontally in a vehicle-mounted state,
The exhaust gas recirculation valve, wherein the housing is provided with a drainage passage communicating with the flow path from the bag space, corresponding to at least a lowermost portion of the bag space. The housing includes a first inner wall portion between the flow path and the seal member, and a second inner wall portion continuous with the first inner wall portion and in contact with a radially outer peripheral surface of the seal member,
2. The exhaust gas recirculation valve according to claim 1, wherein a rust preventive film is formed on the first inner wall portion and at least a part of the second inner wall portion on the flow path side.   3. The exhaust gas recirculation valve according to claim 2, wherein a portion of the tip portion of the rust preventive coating that is in contact with the radially outer peripheral surface of the seal member is tapered.   The exhaust gas recirculation valve according to claim 2 or 3, wherein the antirust coating is formed of a resin material.   5. The exhaust gas recirculation valve according to claim 2, wherein a blade that rotates integrally with the rotation shaft is provided between the rotation shaft and the first inner wall portion in the bag space. .

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