JP3737874B2 - Cover structure for driving part of electric exhaust gas recirculation valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionMotorizedMore particularly, the exhaust gas recirculation valve drive cover structureMotorizedOf the exhaust gas recirculation valveelectromagneticA part of the drive unit is configured to be surrounded by the cover memberMotorizedThe present invention relates to a cover structure for a driving part of an exhaust gas recirculation valve.
[0002]
[Prior art]
Conventionally, for example, an exhaust gas recirculation valve has been used to remove harmful components discharged from an internal combustion engine. The exhaust gas recirculation valve recirculates the exhaust gas discharged from the internal combustion engine to the intake system and reduces harmful components such as NOx contained in the exhaust gas to reduce the harmful components such as NOx. Has the function of communicating with the system.
[0003]
Generally, an exhaust gas recirculation valve is driven via a valve that opens and closes a recirculation path that connects an intake system and an exhaust system of an internal combustion engine by a valve body, and a valve shaft that connects the valve to the valve body. A drive device and guide means for supporting the valve shaft so as to be able to advance and retreat are provided. Between the drive device and the guide means, heat of exhaust gas introduced into the valve is transmitted to the drive device. A space for preventing this is provided.
[0004]
As shown in FIG. 3 of US Pat. No. 5,460,146 (hereinafter referred to as the first conventional example), the conventional guide means is a plate that also serves as a spring guide with which the lower end of the spring abuts. It arrange | positions at the bottom part side of a housing, and is comprised so that the bottom part and drive part of this housing may be interrupted | blocked.
[0005]
In addition, as is apparent from FIG. 1 of US Pat. No. 5,588,414 (hereinafter referred to as a second conventional example), the guide means belonging to another prior art is a lower side that constitutes the drive device. The magnetic pole piece is fixed to the magnetic pole piece, and the guide member and the lower magnetic pole piece block the space between the bottom portion of the housing and the driving portion.
[0006]
[Problems to be solved by the invention]
However, in the first conventional example, since the plate is exposed at the bottom of the housing, when contaminated water or the like enters from the shaft insertion hole defined in the plate, the lower end of the spring becomes the contaminated water or the like. There is a concern that corrosion may occur due to touching.
[0007]
Further, in the second conventional example, since the structure in which the guide member is fixed to the lower magnetic pole piece is adopted, the shape of the lower magnetic pole piece becomes complicated and the manufacturing thereof is not easy. is there.
[0008]
  The present invention has been made to solve the above-described disadvantages, and can be easily processed and assembled.electromagneticIt is possible to reliably prevent entry into the drive unitMotorizedIt is an object of the present invention to provide a cover structure for a driving part of an exhaust gas recirculation valve.
[0009]
[Means for Solving the Problems]
  In order to solve the above problems, the present invention provides:
  A valve body for opening and closing a fluid flow path defined in the valve base;Has a cooling windowDisposed in the housing and displaces the valve body integrally with the valve shaft.electromagneticA drive unit, and a guide unit that supports the valve shaft in a displaceable manner;A cover member provided inside the housing and surrounding the electromagnetic drive part or the guide part, or a part of the electromagnetic drive part and the guide part;Consist ofMotorizedConfigure the exhaust gas recirculation valveMotorizedThe exhaust gas recirculation valve drive unit cover structure,
  The cover member is defined in a central portion, and a hole portion into which the guide portion is fitted,
  A through hole formed from the peripheral edge to the central portion and rising upward, and formed between the peripheral edge and the central portion;
  With
  The cover member is fixed to a magnetic pole member constituting the electromagnetic drive unit.It is characterized by that.
[0010]
  According to the present invention,electromagneticDrive unit or guide unit, orelectromagneticA part of the drive part and the guide part is surrounded by a cover member.Since the cover member is fixed to the magnetic pole member constituting the electromagnetic drive unit, when the contaminated water or the like enters the housing, the cover member is prevented from entering the electromagnetic drive unit. Also, the cover member is easy to assemble because it is fitted to the guide part through the hole in the center part, and since it is formed to rise upward from the peripheral part toward the center part, AboveContaminated water, etc.Circulates from the central side toward the peripheral side,Entering the guide is prevented.
[0011]
  Further, since the cover member is provided with a through hole between the peripheral portion and the central portion, the contaminated water or the like that has entered the cover member through the through hole is accumulated in the peripheral portion, and again, It is discharged through the through hole. Accordingly, contaminated water or the like is prevented from entering the electromagnetic drive unit or the guide unit.
[0012]
  furtherAlsoSince the cover member is interposed between the magnetic pole member and the guide portion, the guide portion fitted to the cover member can be configured to be short. Further, since the magnetic pole member is configured to be fitted to the guide portion via the cover member, the structure of the magnetic pole member can be simplified, and the processing thereof is facilitated.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, according to the present inventionMotorizedA preferred embodiment of the cover structure for the drive part of the exhaust gas recirculation valve will be described in detail with reference to the accompanying drawings.
[0015]
First, the exhaust gas recirculation valve 10 to which the cover unit 80 is applied together with the cover unit 80 as the cover structure according to the present embodiment will be described.
[0016]
As shown in FIG. 1, the exhaust gas recirculation valve 10 includes a valve unit 20 that controls circulation of exhaust gas from an exhaust system (not shown) of an internal combustion engine coupled to the exhaust gas recirculation valve 10 to the intake system, The guide unit 50 includes a driving unit 90 that drives the valve unit 20, and a sensor unit 160 that measures the open / closed state of the valve unit 20.
[0017]
The valve unit 20 includes a valve base 22, and an inlet port 26 connected to the exhaust system of the internal combustion engine and an outlet port 28 connected to the intake system of the internal combustion engine, for example, on the lower surface of the valve base 22. The inlet port 26 and the outlet port 28 communicate with each other by an upper hole 30 defined in the upper portion of the inlet port 26 and a recirculation path 32 defined in the valve base 22. . The upper hole 30 is formed so as to open from the upper part of the inlet port 26 to the upper surface of the valve base 22. An annular valve seat 34 is disposed in the inlet port 26, and a valve shaft 38 penetrating the valve base 22 is inserted into the valve seat 34 through the inlet port 26 and the upper hole 30. A valve main body 36 is connected to the tip of the valve shaft 38, and the valve main body 36 can open and close the inlet port 26 by contacting the lower end of the valve seat 34. The upper surface of the valve base 22 is brought into contact with the lower surface of the housing 40 via a seal member 78 described later, and is fixed to the housing 40 by, for example, a plurality of screws 76.
[0018]
The housing 40 is formed of, for example, a metal material, and includes a cylindrical side wall 42 and a bottom wall 44 that integrally extends from the lower end of the side wall 42 and extends in the horizontal direction in FIG. Further, a window portion 45 is formed in the housing 40 across the side wall 42 and the bottom wall 44, and the inside and outside (atmosphere side) of the housing 40 communicate with each other through the window portion 45. Furthermore, a hole 46 is defined in a substantially central portion of the bottom wall 44, and the valve shaft 38 is coaxially inserted through a guide member 52 fitted in the hole 46. That is, the valve shaft 38 inserted into the housing 40 is supported by the guide portion 50.
[0019]
The guide portion 50 includes the guide member 52 formed of a heat resistant material (for example, a carbon sintered body) for supporting the valve shaft 38. The guide member 52 has a shaft insertion hole 54 defined therein. It has a substantially cylindrical shape, and is formed of an integrally formed product having large and small diameters, the upper portion being a large diameter portion 58 and the lower portion being a small diameter portion 56. The guide member 52 is sandwiched inside and shielded from the outside by a first guide cover 60 and a second guide cover 66 made of a heat-resistant material disposed coaxially with the valve shaft 38. . In this case, spaces are formed between the first guide cover 60 and the lower surface of the guide member 52 and between the second guide cover 66 and the upper surface of the guide member 52, respectively.
[0020]
The first guide cover 60 is formed in a substantially cup shape having an inner diameter corresponding to the small-diameter portion 56 of the guide member 52, and a first flange portion 62 is integrally provided at the opened upper end so as to be directed outward. . Further, a first hole 64 for inserting the valve shaft 38 is defined in the closed bottom surface of the first guide cover 60. The first guide cover 60 is inserted into the upper hole 30 of the valve portion 20 with the first flange portion 62 side up, and is annularly defined by the first flange portion 62 at the center of the upper surface of the valve base 22. The groove 63 is fitted and locked.
[0021]
The second guide cover 66 is formed in a substantially cup shape, the upper side thereof is a small diameter portion 68 having a smaller diameter than the lower side, and the lower side is a large diameter portion corresponding to the large diameter portion 58 of the guide member 52. 70. A second hole 74 for inserting the valve shaft 38 is defined in the closed upper surface of the second guide cover 66, and a second flange portion 72 is directed outward at the opened lower end. Provided integrally. The second guide cover 66 is inserted into the housing 40 through the hole 46 with the second flange portion 72 facing downward, and is locked to the lower surface of the housing 40 by the second flange portion 72. With this configuration, the guide member 52 is shielded from the bottom portion of the housing 40 by the second guide cover 66, so that contaminated water or the like that has entered the housing 40 is prevented from entering the guide member 52.
[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 valve base 22 with the seal member 78 interposed therebetween, and are fixed by the plurality of screws 76 as described above. The Here, the valve shaft 38 is inserted into the guide portion 50 through the shaft insertion hole 54 of the guide member 52, the first hole 64 of the first guide cover 60, and the second hole 74 of the second guide cover 66. It is supported so as to be displaceable along the direction.
[0023]
As shown in FIG. 2, the cover portion 80 as the cover structure according to the present embodiment includes a substantially cup-shaped cover member 82, and a flange portion 84 is directed outwardly at the opened upper end of the cover member 82. And are provided integrally. In addition, a hole 86 having a diameter corresponding to the small diameter portion 68 of the second guide cover 66 is defined at a substantially central portion of the cover member 82, and a plurality of ventilation holes 88 are defined around the hole 86. In this case, it is preferable that the cover member 82 is formed in a convex shape that is inclined upward from its peripheral edge to the central portion. Then, the flange portion 84 of the cover member 82 is fixed to a second support member 94 described later by welding or the like, and the small diameter portion 68 of the second guide cover 66 is fitted into the hole portion 86 (see FIG. 1).
[0024]
That is, the bottom portion of the housing 40 (the space formed between the bottom wall 44, the side wall 42 of the housing 40 and the bottom surface of the second support member 94 and the sleeve member 106 constituting the drive unit 90 described later) and the drive. The cover member 82 is interposed between the portion 90 (particularly on the sleeve member 106 side) and the second hole 74 of the second guide cover 66. As described above, the cover member 82 extends from the periphery to the central portion. Therefore, the contaminated water or the like that has entered the cover member 82 through the vent hole 88 is accumulated in the concave portion formed around the convex portion, and again passes through the convex portion. It is discharged through the pores 88. Therefore, contaminated water or the like that has entered the housing 40 through the window 45 is prevented from entering the inside of the second guide cover 66 (guide member 52) or the drive unit 90 (particularly, inside the sleeve member 106). The Further, exhaust gas that has entered the housing 40 along the valve shaft 38 via the first hole 64 of the first guide cover 60, the shaft insertion hole 54 of the guide member 52, and the second hole 74 of the second guide cover 66. Is discharged to the outside of the housing 40 through the vent hole 88 and the window portion 45.
[0025]
The driving unit 90 includes a first support member 92 and a second support member 94 each having a substantially cylindrical inner hole so that the first support member 92 is positioned at the top and the second support member 94 is positioned at the bottom. A set of magnetic pole members is formed in the housing 40.
[0026]
The first support member 92 extends so as to be orthogonal to the valve shaft 38 and has a first flange portion 96 whose end is fixed to the upper portion of the housing 40, and a first cylinder extending along the valve shaft 38. Part 93.
[0027]
On the other hand, the second support member 94 extends along the valve shaft 38, the second flange portion 98 extending perpendicularly to the valve shaft 38 and having an end fixed to the lower portion of the housing 40, and The first support member 92 includes a first cylindrical portion 93 and a second cylindrical portion 97 facing the first cylindrical portion 93. Here, the 2nd cylindrical part 97 is formed in the taper shape which becomes a small diameter as the outer periphery goes up. With such a structure, an electromagnetic force in the axial direction applied to the plunger 110 described later is proportional to the position of the plunger 110.
[0028]
As described above, the first support member 92 and the second support member 94 are fixed to the inner surface of the side wall 42 by the first flange portion 96 and the second flange portion 98 formed on the respective outer peripheral surfaces, and the second flange portion. The flange portion 84 of the cover member 82 is fixed to the lower surface of 98. Here, a space is formed from 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 portion 45. In this case, since the heat of the exhaust gas transmitted into the housing 40 through the valve unit 20 and the guide unit 50 is discharged to the outside through the window unit 45, the heat is transmitted to the drive unit 90 side. That is blocked.
[0029]
A coil 102 for driving the valve shaft 38 is disposed in the space 100 formed by the first support member 92, the second support member 94 and the housing 40, and is fixed by a spring washer 104. A power supply device (not shown) is connected to the coil 102. In the inner holes of the first support member 92 and the second support member 94, a sleeve member 106 made of a non-magnetic material and having a substantially cup shape is inserted with its bottom face down, and the sleeve member 106 opened. The upper end of the first support member 92 is locked to the upper end of the first support member 92 by a protrusion 108 formed by curving the upper end of the first support member 92 outward. A concave portion 116 is formed on the bottom surface of the sleeve member 106 and has a downward convex cup shape and functions as a guide for a first elastic member 132 to be described later, and a valve inserted into the housing 40 at the approximate center thereof. A hole through which the shaft 38 is inserted is defined.
[0030]
Inside the sleeve member 106, a substantially cylindrical plunger 110 made of a magnetic material is inserted slidably on the inner surface of the sleeve member 106 and coaxially with the valve shaft 38. The plunger 110 and the valve shaft 38 are connected by a 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, and by configuring in this way, a direction orthogonal to the axis of the plunger 110 and the valve shaft 38. Relative displacement is allowed, and drive of the valve shaft 38 is not hindered due to misalignment of the plunger 110 or fluctuation in the direction perpendicular to the axis of the valve shaft 38. Accordingly, it is easy to manufacture the plunger 110 (particularly, the projection 112), and the guide member 52 that supports the valve shaft 38 can be configured to be short.
[0031]
The connecting means 120 includes a first retainer 122. The first retainer 122 is formed in a substantially disk shape having a smaller diameter than the inner diameter of the plunger 110 corresponding to the recess 116 formed in the bottom surface of the sleeve member 106, and its outer periphery. A first curved portion 123 that is curved downward is provided at the end. In addition, a first engagement hole 124 is defined substantially at the center of the first retainer 122, and the first engagement hole 124 is inserted into a first annular groove 130 defined on the outer peripheral surface of the valve shaft 38. The first elastic member 132 and / or the second elastic member 134 is fixed to the valve shaft 38 by upward biasing.
[0032]
The first elastic member 132 is formed in a substantially cylindrical shape having a diameter corresponding to the concave portion 116 of the first retainer 122 and the sleeve member 106, and is arranged coaxially with the valve shaft 38 between the first retainer 122 and the concave portion 116. Established. At this time, the displacement of the first elastic member 132 in the horizontal direction in FIG. 1 is restricted by the inclined configuration around the first bending portion 123 and the recess 116 of the first retainer 122.
[0033]
The second elastic member 134 is formed in a substantially cylindrical shape having a smaller diameter than the first elastic member 132, and is disposed coaxially with the valve shaft 38 inside the first elastic member 132. The second elastic member 134 has an upper end abutting on the first retainer 122 and a lower end abutting on the second retainer 136, and biases the first retainer 122 upward and the second retainer 136 downward. At this time, the displacement of the second elastic member 134 in the horizontal direction in FIG. 1 is restricted by the valve shaft 38 and the second bending portion 138 of the second retainer 136.
[0034]
The second retainer 136 is disposed on the valve shaft 38 that is spaced apart from the first retainer 122 by a predetermined distance. 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 that is curved upward is provided at the outer peripheral end thereof. It is done. By the second bending portion 138, the horizontal displacement of the second elastic member 134 is restricted in the drawing. Further, a second engaging hole 140 is defined in a substantially central portion of the second retainer 136, and the second engaging hole 140 is fitted into a second annular groove 144 formed in the valve shaft 38 to thereby form the valve. It is engaged with the shaft 38 and is fixed by a downward urging force by the second elastic member 134. In this case, the second retainer 136 restricts the lower limit of the plunger 110 by contacting the recess 116 of the sleeve member 106.
[0035]
A third retainer 146 is disposed on the upper side of the first retainer 122 along the valve shaft 38 so as to be slidable with respect to the valve shaft 38. The third retainer 146 is formed in a substantially disc shape having a diameter substantially the same as that of the first retainer 122, and a third curved portion 148 that is curved upward is provided at an outer peripheral end thereof. A sliding hole 150 for inserting the valve shaft 38 is defined at a substantially central portion of the third retainer 146. The third retainer 146 is urged downward by the third elastic member 154.
[0036]
The third elastic member 154 is formed in a substantially cylindrical shape corresponding to the third retainer 146 and having substantially the same diameter as the first elastic member 132, and the valve shaft 38 is interposed between the third retainer 146 and the sensor case 162. And coaxially arranged. The horizontal displacement of the third elastic member 154 in FIG. 1 is restricted by the third curved portion 148 of the third retainer 146 and the outer peripheral surface of the bearing 166 formed at the lower end of the sensor case 162.
[0037]
The plunger 110 is formed with a protrusion 112 that protrudes toward the valve shaft 38, and the third retainer 146 contacts the upper surface of the protrusion 112 and the first retainer 122 contacts the lower surface. In the state where no current or voltage is applied to the coil 102, the plunger 110 is stopped at the upper limit position by the upward biasing by the first elastic member 132. At this time, the valve body 36 is seated on the valve seat 34 (closed state). Here, the third elastic member 154 urges the plunger 110 downward via the third retainer 146, thereby causing the plunger 110 to collide with the lower surface of the sensor case 162 and to the valve seat 34 of the valve body 36. Shock is shocked in the event of a collision. Further, the protrusion 112 of the plunger 110 is always in contact with the first retainer 122, and vibrations that may occur when the first retainer 122 is separated from the protrusion 112 are prevented.
[0038]
The sensor unit 160 includes a sensor case 162 made of, for example, a resin material that accommodates the sensor unit 160, and the sensor case 162 is connected to the upper portion of the housing 40. A 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 portion 20 by the valve body 36 is transmitted to the sensor via the valve shaft 38 and the sensor rod 164 and is measured by the sensor. The measurement result is sent to a control circuit (not shown) via a connector (not shown) disposed in the sensor case 162. In addition, a connector (not shown) for connecting the coil 102 and a power supply device (not shown) is provided in the sensor case 162, and a connecting portion between the sensor case 162 and the housing 40 is fixed by a fixing means 170. .
[0039]
The fixing means 170 includes an annular groove 190 having a substantially U-shaped cross section defined on the outer peripheral surface of the upper end side of the housing 40, and a step portion 192 formed on the outer peripheral surface of the lower side of the sensor case 162. A crown-like elastic body 172 that fixes the joint surface between the sensor case 162 and the housing 40 is attached to the joint portion between the 162 and the housing 40 via the annular groove 190 and the step portion 192.
[0040]
The coronal elastic body 172 has an annular cylindrical portion 174 corresponding to the shape of the outer peripheral surface of the sensor case 162 and the housing 40 to which the coronal elastic body 172 is attached, and a flange portion is provided at the upper end of the cylindrical portion 174. 176 is integrally provided inwardly. Here, the coronal elastic body 172 is formed of, for example, a metal material having excellent elasticity. The flange portion 176 abuts on the step portion 192 of the sensor case 162 and presses the sensor case 162 by its elastic force.
[0041]
The cylindrical portion 174 is provided with a plurality of raised portions 180 at positions corresponding to the annular groove 190 of the housing 40. The cut-and-raised portion 180 is engaged with the annular groove 190 to prevent the crown-like elastic body 172 from falling off. That is, the coronal elastic body 172 fixes the joint surface between the sensor case 162 and the housing 40 by the interaction between the engagement of the cut and raised portion 180 with the annular groove 190 and the pressing of the step portion 192 by the flange portion 176.
[0042]
The cover portion 80 according to the present embodiment is basically configured as described above, and next, its operation and effects will be described.
[0043]
First, the assembly work of the cover unit 80 will be described.
[0044]
The cover member 82 constituting the cover portion 80 has a flange portion 84 fixed to a second flange portion 98 formed on the outer peripheral surface of the second support member 94 by welding or the like, and is integrated with the second support member 94. It is fixed in the housing 40. Then, the small diameter portion 68 of the second guide cover 66 is inserted into the hole portion 86.
[0045]
Next, the operation of the cover unit 80 will be described including the operation of the exhaust gas recirculation valve 10.
[0046]
In the exhaust gas recirculation valve 10, the valve unit 20 is opened by applying a current or voltage to the coil 102 of the driving unit 90, and the application of the current or voltage to the coil 102 is stopped. The valve section 20 is closed.
[0047]
That is, when a predetermined current or voltage is applied to the coil 102 from a power supply device (not shown) based on an instruction from a control circuit (not shown), a magnetic field is generated from the coil 102 and the plunger 110 moves downward. To receive electromagnetic force. Here, since the second cylindrical portion 97 of the second support member 94 is formed in a taper shape having a smaller diameter as the outer periphery thereof goes upward, the electromagnetic force in the axial direction applied to the plunger 110 is applied to the plunger 110. Proportional to position.
[0048]
When the plunger 110 presses the first retainer 122 via the projection 112 and is displaced downward while resisting the elastic force of the first elastic member 132, the valve shaft 38 connected to the first retainer 122 is The guide member 52 is displaced downward under the guide action. At this time, the valve main body 36 coupled to the valve shaft 38 is displaced downward and separated from the valve seat 34, whereby the inlet port 26 and the outlet port 28 are communicated with each other (valve open state). The plunger 110 stops at a position where the electromagnetic force described above 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 or voltage applied to the coil 102.
[0049]
Here, the lower limit position of the plunger 110 is regulated by the second retainer 136. Therefore, it is avoided that the plunger 110 collides with the bottom surface of the sleeve member 106 and is damaged.
[0050]
Next, when the application of the current or voltage to the coil 102 is stopped, the plunger 110 is lifted by the upward biasing by the elastic force of the first elastic member 132, and accordingly, the valve shaft 38 moves the guide of the guide member 52. Displaces upward under action. The valve main body 36 coupled to the valve shaft 38 is seated on the valve seat 34, and the inlet port 26 is closed (valve closed state).
[0051]
Here, the third elastic member 154 urges the plunger 110 downward via the third retainer 146, thereby buffering the impact when the plunger 110 collides with the lower surface of the sensor case 162, and The impact at the time of collision of the valve body 36 against the valve seat 34 is also buffered via the valve shaft 38 and the second retainer 136. Further, by the downward urging by the third elastic member 154, the protrusion 112 of the plunger 110 is always in contact with the first retainer 122, and the occurrence of vibration due to the separation thereof is prevented. Further, since the plunger 110 and the first retainer 122 are not directly coupled, the inertial force of the plunger 110 is not applied to the valve shaft 38 during the valve closing operation. Therefore, when the valve body 36 collides with the valve seat 34, the valve body 36 or the valve seat 34 is prevented from being damaged.
[0052]
Further, since a predetermined gap is provided between the valve shaft 38 and the protrusion 112 of the plunger 110, relative displacement in a direction perpendicular to the axis line between the plunger 110 and the valve shaft 38 is allowed, and The drive of the valve shaft 38 is not hindered due to the misalignment of the plunger 110 or the fluctuation in the direction perpendicular to the axis of the valve shaft 38.
[0053]
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 the measurement result by the sensor is fed back to the control circuit.
[0054]
By the way, when the valve shaft 38 is displaced, the exhaust gas passes through the first hole 64 of the first guide cover 60, the shaft insertion hole 54 of the guide member 52, and the second hole 74 of the second guide cover 66. However, since the exhaust gas is at a higher pressure than the atmosphere side, the exhaust gas is likely to enter between the second guide cover 66 and the drive unit 90, so that the exhaust gas passes through the vent hole 88 of the cover member 82 and the window portion 45 of the housing 40. It is discharged outside the housing 40 (see FIG. 3).
[0055]
Further, by adopting a configuration in which the second guide cover 66 is fitted to the cover member 82 attached to the second support member 94, the bottom portion of the housing 40, the drive unit 90 (especially the sleeve member 106 side), and the above-mentioned The cover member 82 is interposed between the second hole 74 of the second guide cover 66. In addition, as described above, the bottom surface of the cover member 82 is formed in a convex shape that is inclined upward from the peripheral edge to the center portion thereof, so that the contaminated water or the like that has entered the cover member 82 through the vent hole 88 or the like. Accumulates in a concave portion formed around the convex portion and is discharged again through the vent hole 88. Accordingly, the contaminated water or the like that has entered the housing 40 through the window 45 is exposed between the small diameter portion 68 of the valve shaft 38 and the bottom surface of the sleeve member 106, and further, the second guide cover 66 Entering the inside (guide member 52) or the drive unit 90 (particularly, inside the sleeve member 106) is avoided.
[0056]
Further, since the cover member 82 is formed in a substantially cup shape separately from the second support member 94 as described above, the cover member 82 can be easily manufactured by pressing or the like, and The structure of the second support member 94 is also simple and easy to manufacture. Further, since the cover member 82 is fixed to the second support member 94 by welding or the like, it can be easily assembled.
[0057]
Furthermore, since the cover member 82 is fixed to the second support member 94 and is formed so as to protrude to the guide portion 50 side, the guide portion 50 (the second guide cover 66 that fits with the cover member 82) is formed. And the guide member 52 accommodated in the inside can be comprised in short length. Therefore, the entire exhaust gas recirculation valve 10 can be reduced in size.
[0058]
Various modifications can be made to the cover portion 80 configured as described above. For example, the cover member 82 may be provided with a ventilation groove 200 formed by cutting out a part of the outer periphery of the hole 86 instead of the ventilation hole 88 (see FIG. 4).
[0059]
In addition, even if the cover member 82 is directly fitted to the guide member 52 without providing the second guide cover 66 in the guide portion 50, the shaft insertion hole 54 or the drive of the guide member 52 is driven as in the above case. An effect of preventing contaminated water or the like from entering the portion 90 (particularly the sleeve member 106 side) is obtained.
[0060]
【The invention's effect】
  According to the present inventionMotorizedAccording to the cover structure for the exhaust gas recirculation valve drive unit, it can be easily processed and assembled, and contaminated water, etc.electromagneticDrive partAnd guide sectionIt is possible to reliably prevent entry. Therefore, it is possible to realize an exhaust gas recirculation valve that has a simple configuration and is highly durable without causing corrosion or the like.MotorizedA cover structure for the drive part of the exhaust gas recirculation valve is obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an exhaust gas recirculation valve to which a cover structure according to the present embodiment is applied.
FIG. 2 is a perspective view showing a cover structure according to the present embodiment.
FIG. 3 is a partial cross-sectional view showing a cover structure according to the present embodiment.
FIG. 4 is a perspective view showing another example of a cover structure according to the present embodiment.
[Explanation of symbols]
10 ... Exhaust gas recirculation valve 20 ... Valve part
40 ... Housing 50 ... Guide part
66 ... Second guide cover 80 ... Cover part
82 ... Cover member 84 ... Flange
86 ... hole 90 ... driving unit
94. Second support member

Claims (1)

A valve body that opens and closes a fluid flow path defined in the valve base; an electromagnetic drive unit that is disposed in a housing having a cooling window; and that displaces the valve body integrally with a valve shaft; A guide portion that supports the valve shaft so as to be displaceable, and a cover member that is provided inside the housing and surrounds the electromagnetic drive portion or the guide portion, or a part of the electromagnetic drive portion and the guide portion. A cover structure for the drive part of the electric exhaust gas recirculation valve constituting the electric exhaust gas recirculation valve,
The cover member is defined in a central portion, and a hole portion into which the guide portion is fitted,
A through hole formed from the peripheral edge to the central portion and rising upward, and formed between the peripheral edge and the central portion;
With
It said cover member is secured to said pole member constituting an electromagnetic driving unit driver cover structure of an electric exhaust gas recirculation valve according to claim Rukoto.

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