JP2004100484A - Exhaust gas recirculation valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce slide resistance when a plunger is displaced along an axial direction inside a sleeve member. <P>SOLUTION: This valve includes a base part 22 in which an inlet port 26 and an outlet port 28 for exhaust gas to communicate are formed; a housing 40 which is connected with an upper part of the base part 22 and in which a driving part 90 is disposed in an inner part; the sleeve member 106 which is attached inside the driving part 90 and comprises non-magnetic material; the plunger 110 which is provided under driving work of the driving part 90 along the inner-periphery surface of the sleeve member 106 so as to freely slide and in which a DLC coating 114 is applied to the outer-periphery surface; a valve stem 38 which is provided under displacement work in the axial line direction of the plunger 110 so as to be integrally displaced; and a valve body 36 connected with the front end part of the valve stem 38 and opens/closes a valve seat 34 for communicating the exhausted gas. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exhaust gas recirculation valve, and more particularly, to an exhaust gas recirculation valve in which a sliding surface of a movable member and / or a fixed member is subjected to a surface treatment.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, for example, an exhaust gas recirculation valve has been used to remove harmful components emitted from an internal combustion engine. The exhaust gas recirculation valve recirculates exhaust gas discharged from the internal combustion engine to an intake system, and reduces exhaust gas and harmful components such as NOx contained in the exhaust gas. It has the function of communicating with the system.
[0003]
Generally, an exhaust gas recirculation valve performs a displacement operation by driving a valve body that opens and closes a recirculation path that connects an intake system and an exhaust system of an internal combustion engine, and a valve shaft that is connected to the valve body. And a drive unit.
[0004]
The exhaust gas recirculation valve has an armature that is displaced along the axial direction under the driving action of the driving device, and the armature is integrally connected to the valve shaft. When the armature is displaced in the axial direction, the outer peripheral surface slides along the inner peripheral surface of the guide sleeve mounted inside the driving device (for example, see Patent Document 1).
[0005]
[Patent Document 1]
JP 2001-197715 A (Page 2, FIG. 8)
[0006]
[Problems to be solved by the invention]
By the way, in the exhaust gas recirculation valve according to the related art, when the armature is displaced along the axial direction integrally with the valve shaft under the driving action of the driving device, a sliding resistance is generated between the armature and the guide sleeve. Occurs. At that time, the armature and the guide sleeve are worn due to sliding resistance, and the durability is reduced due to long-term use.
[0007]
In addition, the amount of displacement of the valve shaft, which is displaced integrally with the armature, changes due to wear of the armature, and it is difficult to control the flow rate of exhaust gas flowing through the recirculation path with high accuracy. .
[0008]
The present invention has been made in consideration of the above-described problems, and provides an exhaust gas recirculation valve capable of reducing sliding resistance when a movable member is displaced and improving durability and accuracy. The purpose is to do.
[0009]
[Means for Solving the Problems]
To achieve the above object, the present invention provides a base having a valve seat and a circulation flow path for exhaust gas,
A valve stem that includes a valve body that opens and closes a circulation flow path of the exhaust gas, and extends outward through the base.
A drive unit for displacing the valve shaft integrally with the valve body,
A valve shaft guide that is provided between the drive unit and the base unit and that supports the valve shaft in a displaceable manner;
An exhaust gas recirculation valve having
A fixing member attached to the driving unit,
A movable member that slides in the axial direction along the inner wall surface of the fixed member,
With
A sliding surface of the movable member with respect to the fixed member and / or an inner wall surface of the fixed member is surface-treated with an amorphous carbon material.
[0010]
According to the present invention, the inner wall surface of the fixed member mounted on the drive unit and / or the sliding surface of the movable member that slides in the axial direction along the inner wall surface of the fixed member are surface-treated with the amorphous carbon material. Thereby, the sliding resistance when the movable member slides along the inner wall surface of the fixed member along the axial direction can be reduced, and the slidability can be improved. Therefore, since the wear amount of the movable member and the fixed member is reduced, the durability of the movable member and the fixed member on which the movable member slides can be improved.
[0011]
Further, the wear resistance of the movable member and the fixed member can be improved, and the movable member can be accurately displaced with respect to the fixed member. Therefore, the valve shaft is accurately displaced along the axial direction with the displacement of the movable member, and the flow rate of the exhaust gas flowing through the circulation passage can be controlled with high accuracy.
[0012]
Further, in the order of a coating layer made of silicon or chromium, and an amorphous carbon material in a radially outward direction from a sliding surface of the movable member and / or in a radially inward direction from an inner peripheral surface of the fixed member. It is preferable to perform a surface treatment. Since the coating layer is formed in advance as a base when applying the amorphous carbon material to the movable member and / or the fixed member, the surface treatment with the amorphous carbon material is more reliably performed on the movable member and / or the fixed member. Because it can be applied.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the exhaust gas recirculation valve according to the present invention will be described below in detail with reference to the accompanying drawings.
[0014]
In FIG. 1, reference numeral 10 indicates an exhaust gas recirculation valve according to an embodiment of the present invention. The exhaust gas recirculation valve 10 includes a valve unit 20 that controls circulation of exhaust gas from an exhaust system (not shown) of the internal combustion engine to an intake system, a guide unit 50, and a driving unit 90 that drives the valve unit 20. And a sensor section 160 for measuring the open / closed state of the valve section 20.
[0015]
The valve portion 20 includes a base portion 22. An inlet port 26 connected to an exhaust system of the internal combustion engine and an outlet port 28 connected to an intake system of the internal combustion engine are formed at, for example, a lower portion of the base portion 22. The inlet port 26 and the outlet port 28 are formed with a hole 30 defined above the inlet port 26 and a recirculation passage 32 which is a circulation flow path of exhaust gas defined in the base 22. And are communicated by.
[0016]
The hole 30 is formed so as to open from the upper part of the inlet port 26 to the upper surface of the base 22. An annular valve seat 34 is disposed at the inlet port 26, and a valve shaft 38 that penetrates the base 22 through the inlet port 26 and the hole 30 is inserted into the valve seat 34.
[0017]
A valve body 36 is connected to one end of the valve shaft 38. The valve body 36 can open and close the inlet port 26 by being separated from or seated on the valve seat 34.
[0018]
The housing 40 is formed of, for example, a metal material, and has a cylindrical side wall 42 and a bottom wall 44 integrally and horizontally extending from a lower end of the side wall 42. A window 45 is formed in the housing 40 across the side wall 42 and the bottom wall 44, and the inside of the housing 40 communicates with the outside (atmosphere side) via the window 45. Further, a hole 46 is defined substantially at the center of the bottom wall 44, and the valve shaft 38 is coaxially inserted through the valve shaft guide 52 fitted in the hole 46. That is, the valve shaft 38 inserted into the housing 40 is supported by the guide part 50 so as to be slidable in the vertical direction.
[0019]
The guide portion 50 includes a valve shaft guide 52 formed of a heat-resistant material (for example, a carbon sintered body or stainless steel) for supporting the valve shaft 38. The valve shaft guide 52 has a shaft insertion hole 54 and a bearing escape portion 55 defined therein, and includes an under cover 60 and an upper cover 66 formed of a heat-resistant material disposed coaxially with the valve shaft 38. It is fitted so as to be surrounded and shielded from the outside.
[0020]
The under cover 60 is formed in a substantially cup shape, and a first flange portion 62 extending radially outward from the opened upper end is engaged with an annular groove 63 defined in a substantially central portion of the upper surface of the base 22. Is stopped. Further, a first hole 64 for inserting the valve shaft 38 is defined in the closed bottom surface of the under cover 60.
[0021]
The upper cover 66 is formed in a substantially cup shape, and a second hole 74 through which the valve shaft 38 is inserted is defined at a substantially central portion of an upper portion thereof. The second flange portion 72 provided on the housing 40 is locked to the lower surface of the housing 40.
[0022]
The first flange portion 62 and the second flange portion 72 are sandwiched between the lower surface of the housing 40 and the upper surface of the base 22 with a sealing member 78 interposed therebetween, and are fixed by a plurality of screws 76. A plurality (for example, three) of screw holes 79 for inserting the screws 76 are defined in the seal member 78. Here, the valve shaft 38 is inserted into the guide portion 50 through the shaft insertion hole 54 of the valve shaft guide 52, the first hole 64 of the under cover 60, and the second hole 74 of the upper cover 66. The valve shaft 38 is supported so as to be displaceable along the axial direction.
[0023]
The cover portion 80 includes a cover member 82 having a substantially cup shape, and a flange portion 84 is integrally provided at an open upper end of the cover member 82 so as to extend in a radially outward direction. A hole 86 having a diameter corresponding to the upper cover 66 is defined at a substantially central portion of the cover member 82, and the upper cover 66 is fitted into the hole 86. A plurality of ventilation holes 88 are defined around the hole 86. The flange portion 84 of the cover member 82 is fixed to a second support member 94 described later by welding or the like.
[0024]
The driving unit 90 includes a first support member 92 and a second support member 94 having a substantially cylindrical inner hole. The first support member 92 is located at the upper part, and the second support member 94 is located at the lower part. Are arranged in the housing 40 to form a set of magnetic pole members.
[0025]
The first support member 92 extends in a direction perpendicular to the valve shaft 38 and has a first flange portion 96 having an end fixed to an upper portion of the housing 40, and a cylindrical member extending along the valve shaft 38. And a first bulging portion 93. On the other hand, the second support member 94 extends perpendicular to the valve shaft 38 and has a second flange portion 98 whose end is fixed to a lower portion of the housing 40, and extends along the valve shaft 38, The first support member 92 includes a first bulge portion 93 and a cylindrical second bulge portion 97 facing the first bulge portion 93. Here, the second bulging portion 97 is formed in a tapered shape having a smaller diameter as its outer periphery extends upward.
[0026]
The first support member 92 and the second support member 94 are fixed to the inner surface of the side wall 42 by a first flange portion 96 and a second flange portion 98 formed on each outer peripheral surface, respectively, and a lower surface of the second flange portion 98 is provided. , A flange portion 84 of the cover member 82 is fixed. Here, a space is formed by the second support member 94, the side wall 42 and the bottom wall 44 of the housing 40, and this space communicates with the outside through the window 45.
[0027]
A coil 102 for driving the valve shaft 38 is provided in a space 100 formed by the first support member 92, the second support member 94, and the housing 40. The coil 102 is wound around a bobbin 101 made of a nonmetallic material, and the bobbin 101 is elastically fixed to the first support member 92 by a spring washer 104 on the second support member 94. A power source (not shown) is connected to the coil 102.
[0028]
A sleeve member (fixing member) 106 formed of a non-magnetic material and having a substantially cup shape is inserted into the inner hole of the first support member 92 and the second support member 94 with its bottom face down. The upper end of the sleeve member 106 is locked to the upper end of the first support member 92 by a protrusion 108 formed by curving outward. On the bottom surface of the sleeve member 106, a downwardly convex cup-shaped protrusion 116 functioning as a guide for a first elastic member 132 described later is formed, and is inserted into the housing 40 at a substantially central portion thereof. An insertion hole (not shown) through which the valve shaft 38 is inserted is defined.
[0029]
A substantially cylindrical plunger (movable member) 110 made of a magnetic material is slidably inserted inside the sleeve member 106 on the inner surface of the sleeve member 106 coaxially with the valve shaft 38. The plunger 110 and the valve shaft 38 are connected by connecting means 120 via a protrusion 112 formed on the inner surface of the plunger 110. Here, a predetermined gap is provided between the valve shaft 38 and the protrusion 112 of the plunger 110.
[0030]
As shown in FIGS. 2 and 3, an amorphous carbon material (DLC-diamond-like carbon) coating (hereinafter, referred to as DLC coating) 114 having high hardness is provided on the outer peripheral surface (sliding surface) of the plunger 110. It has been subjected. In this case, the DLC coating 114 applied to the outer peripheral surface is preferably formed to have a thickness in the range of 0.2 to 10 μm.
[0031]
That is, by applying the DLC coating 114 to the outer peripheral surface of the plunger 110, the slidability when the plunger 110 slides along the inner peripheral surface (inner wall surface) of the sleeve member 106 is improved, and the slidability is improved. Since the wear of the plunger 110 is suppressed with the improvement of the durability, the durability can be improved.
[0032]
Further, the DLC coating 114 is not limited to being directly applied to the outer peripheral surface of the plunger 110, and as shown in FIG. 4, for example, a silicon film and / or a chromium film A two-layer coating may be used in which a coating layer 118 made of is coated and a DLC coating 114 is applied thereon. In this case, the coating layer 118 may have a thickness in the range of 0.1 to 2 μm, and the DLC coating 114 applied on the coating layer 118 may have a thickness in the range of 0.2 to 10 μm. Good to do.
[0033]
The coating layer 118 made of a silicon coating and / or a chrome coating applied to the outer peripheral surface of the plunger 110 is arbitrarily selected based on the material of the plunger 110 to be coated. That is, by previously forming the coating layer 118 on the outer peripheral surface of the plunger 110 as a base of the DLC coating 114, the DLC coating 114 can be more reliably applied to the plunger 110.
[0034]
Further, as shown in FIG. 5, instead of the outer peripheral surface of the plunger 110, the DLC coating 114 may be applied to the inner peripheral surface of the sleeve member 106. In this case, a two-layer coating in which a coating layer 118 made of a silicon coating and / or a chromium coating is formed on the inner peripheral surface of the sleeve member 106 and a DLC coating 114 is further formed thereon may be adopted.
[0035]
Further, as shown in FIG. 6, the DLC coating 114 may be applied to both the outer peripheral surface of the plunger 110 and the inner peripheral surface of the sleeve member 106. Even in that case, a coating layer 118 made of a silicon coating and / or a chrome coating may be applied to both the outer peripheral surface of the plunger 110 and the inner peripheral surface of the sleeve member 106, and the DLC coating 114 may be applied thereon. The coating layer 118 is not limited to a silicon coating or a chromium coating. That is, by previously forming the coating layer 118 on the outer peripheral surface of the plunger 110 as a base of the DLC coating 114, the DLC coating 114 can be more reliably applied to the plunger 110 and the sleeve member 106.
[0036]
As shown in FIG. 1, the connecting means 120 includes a first retainer 122 having a diameter smaller than the inner diameter of the plunger 110 corresponding to the protrusion 116 formed on the bottom surface of the sleeve member 106. A first curved portion 123 that is formed in a substantially disk shape and that is curved downward is provided on the outer peripheral end. A first engagement hole 124 is defined substantially at the center of the first retainer 122, and the first engagement hole 124 is fitted into a first annular groove 130 defined on the outer peripheral surface of the valve shaft 38. Thus, the first elastic member 132 and / or the second elastic member 134 fix the valve shaft 38 by upward urging.
[0037]
The first elastic member 132 is disposed coaxially with the valve shaft 38 between the first retainer 122 and the protrusion 116.
[0038]
The second elastic member 134 is disposed coaxially with the valve shaft 38 inside the first elastic member 132. The upper end of the second elastic member 134 contacts the first retainer 122, and the lower end of the second elastic member 134 contacts the second retainer 136, thereby urging the first retainer 122 upward. 136 is urged downward.
[0039]
The second retainer 136 is disposed on the valve shaft 38 at a predetermined distance below the first retainer 122. The second retainer 136 is formed in a substantially disk shape having a smaller diameter than the first retainer 122 corresponding to the second elastic member 134, and a second curved portion 138 curved upward is provided at an outer peripheral end thereof. .
[0040]
A second engagement hole 140 is defined substantially at the center of the second retainer 136, and the second engagement hole 140 is fitted into a second annular groove 144 formed in the valve shaft 38 by inserting the second engagement hole 140 into the second annular groove 144. It is engaged with the valve shaft 38 and is fixed by downward biasing by the second elastic member 134. In this case, the second retainer 136 restricts the lower limit of the movement range of the plunger 110 by abutting on the protrusion 116 of the sleeve member 106.
[0041]
A third retainer 146 is slidably disposed on the upper side of the first retainer 122 along the valve shaft 38 with respect to the valve shaft 38. The third retainer 146 is formed in a substantially disk shape having substantially the same diameter as the first retainer 122, and has a third curved portion 148 curved upward at the outer peripheral end. At a substantially central portion of the third retainer 146, a slide hole 150 for inserting the valve shaft 38 is defined. Then, the third retainer 146 is urged downward by the third elastic member 154.
[0042]
The third elastic member 154 is formed in a substantially cylindrical shape having substantially the same diameter as the first elastic member 132 corresponding to the third retainer 146, and is coaxial with the valve shaft 38 between the third retainer 146 and the sensor case 162. Arranged above.
[0043]
The plunger 110 is formed with a protrusion 112 protruding toward the valve shaft 38. The upper surface of the protrusion 112 is in contact with the third retainer 146, and the lower surface thereof is in contact with the first retainer 122. When no current is supplied to the coil 102, the plunger 110 is stopped at the upper limit position by the upward bias of the first elastic member 132. At this time, the valve body 36 is seated on the valve seat 34 (valve closed state).
[0044]
The sensor section 160 includes a sensor case 162 formed of, for example, a resin material. The sensor case 162 is connected to an upper portion of the housing 40. The sensor rod 164 of the sensor unit 160 connected to a sensor (not shown) is supported by a bearing 166, and the tip of the sensor rod 164 is connected to the rear end of the valve shaft 38. The open / closed state of the valve section 20 by the valve body 36 is transmitted to the sensor via the valve shaft 38 and the sensor rod 164, and measured by the sensor. This measurement result is sent to a control circuit (not shown) via a connector section 168 provided in the sensor case 162. A connector 168 for connecting the coil 102 to a power supply (not shown) is provided in the sensor case 162, and a connection portion between the sensor case 162 and the housing 40 is fixed by fixing means 170.
[0045]
The exhaust gas recirculation valve 10 according to the present embodiment is basically configured as described above. As an example, in the case where the DLC coating 114 is applied only to the outer peripheral surface of the plunger 110, The operation and the effect will be described.
[0046]
FIG. 1 shows a valve closed state in which the valve body 36 is seated on the valve seat 34 and communication between the inlet port 26 and the outlet port 28 is interrupted.
[0047]
In such a valve closed state, a current is supplied to the coil 102 of the drive unit 90 from a power supply (not shown). Then, a current is supplied to the coil 102 of the drive unit 90 to open the valve unit 20, and the supply of the current to the coil 102 is stopped to close the valve of the valve unit 20. Is
[0048]
That is, when a predetermined value of current is supplied from the power supply to the coil 102 based on an instruction from a control circuit (not shown), a magnetic field is generated from the coil 102, and the plunger 110 moves along the inner peripheral surface of the sleeve member 106. It receives electromagnetic force to move downward. At this time, since the DLC coating 114 having high hardness is applied to the outer peripheral surface of the plunger 110, sliding resistance generated between the outer peripheral surface of the plunger 110 and the inner peripheral surface of the sleeve member 106 can be reduced. . As a result, the slidability of the plunger 110 is improved, and the abrasion of the plunger 110 and the sleeve member 106 due to the improvement in the slidability can be prevented.
[0049]
Further, since the second bulged portion 97 of the second support member 94 is formed in a tapered shape having a smaller diameter as its outer periphery extends upward, the electromagnetic force applied to the plunger 110 in the axial direction is reduced. It is proportional to the position of the plunger 110 along the axial direction.
[0050]
When the plunger 110 presses the first retainer 122 via the protrusion 112 and displaces downward while resisting the elastic force of the first elastic member 132, the valve shaft 38 connected to the first retainer 122. Is displaced downward under the guide action of the valve shaft guide 52. At this time, the valve body 36 connected to the valve shaft 38 is displaced downward and separated from the valve seat 34, so that communication between the inlet port 26 and the outlet port 28 is established (valve open state).
[0051]
Then, the plunger 110 stops at a position where the electromagnetic force and the elastic force of the first elastic member 132 are balanced. That is, the opening / closing amount of the valve unit 20 is determined by the strength of the current supplied to the coil 102.
[0052]
Here, since the lower limit position of the plunger 110 is regulated by the second retainer 136, it is possible to prevent the plunger 110 from colliding with the bottom surface of the sleeve member 106 and being damaged.
[0053]
Next, when the supply of the current to the coil 102 is stopped, the plunger 110 is raised by the upward bias due to the elastic force of the first elastic member 132, and accordingly, the valve shaft 38 moves the valve shaft guide 52. It is displaced upward under the guide action. Then, the valve body 36 connected to the valve shaft 38 is seated on the valve seat 34, and the inlet port 26 is closed (valve closed state). At that time, the DLC coating 114 applied to the outer peripheral surface of the plunger 110 reduces sliding resistance generated between the outer peripheral surface of the plunger 110 and the inner peripheral surface of the sleeve member 106 when the plunger 110 is displaced upward. Is done. As a result, the slidability of the plunger 110 is improved, and the abrasion of the plunger 110 and the sleeve member 106 due to the improvement in the slidability can be prevented.
[0054]
Here, the third elastic member 154 urges the plunger 110 downward through the third retainer 146, thereby buffering an impact when the plunger 110 collides with the lower surface of the sensor case 162, and a valve. Via the shaft 38 and the second retainer 136, the impact when the valve body 36 collides with the valve seat 34 is similarly buffered. In addition, since the projection 112 of the plunger 110 is always in contact with the first retainer 122 by the downward urging by the third elastic member 154, the generation of vibration is prevented.
[0055]
Since the plunger 110 and the first retainer 122 are not directly connected to each other, no inertial force of the plunger 110 is applied to the valve shaft 38 during the valve closing operation. Therefore, when the valve main body 36 collides with the valve seat 34, the valve main body 36 or the valve seat 34 is prevented from being damaged.
[0056]
Further, since a predetermined gap is provided between the valve shaft 38 and the projection 112 of the plunger 110, a relative displacement in a direction orthogonal to the axis of the plunger 110 and the valve shaft 38 is allowed, The driving of the valve shaft 38 is not hindered due to the misalignment of the plunger 110 or the fluctuation of the valve shaft 38 in a direction perpendicular to the axis.
[0057]
The opening / closing state of the inlet port 26 by the valve body 36 is transmitted to a sensor (not shown) via the valve shaft 38 and the sensor rod 164, and a measurement result by the sensor is fed back to a control circuit (not shown).
[0058]
As described above, in the present embodiment, by applying the DLC coating 114 to the outer peripheral surface of the plunger 110 and / or the inner peripheral surface of the sleeve member 106, the plunger 110 moves the inner peripheral surface of the sleeve member 106 along the axial direction. The sliding resistance of the plunger 110 can be improved by reducing the sliding resistance when sliding. As a result, the wear amount of the plunger 110 and the sleeve member 106 is reduced, so that the durability of the plunger 110 and the sleeve member 106 on which the plunger 110 slides can be improved. Further, by improving the slidability of the plunger 110, the plunger 110 can be slid more smoothly along the inside of the sleeve member 106.
[0059]
Further, by improving the wear resistance of the plunger 110 and the sleeve member 106, the plunger 110 can be displaced with respect to the sleeve member 106 with high accuracy. Therefore, the valve shaft 38 is accurately displaced along the axial direction with the displacement of the plunger 110, and the flow rate of the exhaust gas flowing from the inlet port 26 to the outlet port 28 can be controlled with high accuracy.
[0060]
【The invention's effect】
According to the present invention, the following effects can be obtained.
[0061]
That is, the amorphous carbon material applied to the inner wall surface of the fixed member and / or the sliding surface of the movable member reduces sliding resistance when the movable member slides along the inner wall surface of the fixed member along the axial direction. Thus, the wear amount of the movable member and the fixed member can be reduced, and the durability of the movable member and the fixed member on which the movable member slides can be improved.
[0062]
In addition, by improving the wear resistance of the movable member and the fixed member, the movable member can be displaced with high precision with respect to the fixed member, so that the flow rate of the exhaust gas flowing through the circulation flow path can be precisely controlled. Can be controlled.
[Brief description of the drawings]
FIG. 1 is a partially broken longitudinal sectional view of an exhaust gas recirculation valve according to an embodiment of the present invention.
FIG. 2 is a partially cutaway exploded perspective view of a plunger provided with a DLC coating.
FIG. 3 is an enlarged longitudinal sectional view of a partly omitted plunger provided with a DLC coating.
FIG. 4 is a partially omitted enlarged longitudinal sectional view of a plunger provided with two layers of a DLC coating and a coating layer.
FIG. 5 is an enlarged vertical cross-sectional view of a part of a sleeve member on which a DLC coating is applied;
FIG. 6 is a partially omitted enlarged longitudinal sectional view of a plunger and a sleeve member provided with a DLC coating.
[Explanation of symbols]
Reference Signs List 10 exhaust gas recirculation valve 20 valve part 22 base 26 inlet port 28 outlet port 32 recirculation path 34 valve seat 36 valve body 38 valve shaft 40 housing 50 guide part 52 valve shaft Guide 60 ... Under cover 66 ... Upper cover 80 ... Cover part 82 ... Cover member 90 ... Drive part 92 ... First support member 94 ... Second support member 102 ... Coil 106 ... Sleeve member 110 ... Plunger 114 ... DLC coating 118 ... Coating Layer 160 Sensor part 166 Bearing 168 Connector part 170 Fixing means

Claims (2)

A base having a valve seat and a circulation path for exhaust gas,
A valve stem that includes a valve body that opens and closes a circulation flow path of the exhaust gas, and extends outward through the base.
A drive unit for displacing the valve shaft integrally with the valve body,
A valve shaft guide that is provided between the drive unit and the base unit and that supports the valve shaft in a displaceable manner;
An exhaust gas recirculation valve having
A fixing member attached to the driving unit,
A movable member that slides in the axial direction along the inner wall surface of the fixed member,
With
An exhaust gas recirculation valve characterized in that a sliding surface of the movable member with respect to the fixed member and / or an inner wall surface of the fixed member are subjected to a surface treatment with an amorphous carbon material. The exhaust gas recirculation valve according to claim 1,
Surface treatment in the order of a coating layer made of silicon or chromium and an amorphous carbon material in a radially outward direction from a sliding surface of the movable member and / or in a radially inward direction from an inner peripheral surface of the fixed member. An exhaust gas recirculation valve characterized by being provided with:

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