JP6256223B2 - Exhaust control valve - Google Patents

Description

  The present invention relates to an exhaust control valve, and more particularly to an exhaust gas (exhaust) recirculation device that recirculates a part of exhaust gas (exhaust gas) discharged from a cylinder of an internal combustion engine (engine) to an intake pipe as EGR gas. It relates to the exhaust gas recirculation (EGR) control valve used.

[Conventional technology]
2. Description of the Related Art Conventionally, in vehicles such as automobiles, an exhaust gas (exhaust) recirculation device (EGR system) that recirculates a part of exhaust gas (exhaust gas) discharged from a cylinder of an internal combustion engine (engine) to an intake pipe as EGR gas. ) Is installed. In this EGR system, an EGR gas flow rate control valve (hereinafter referred to as an EGR control valve) that controls the flow rate of EGR gas introduced into the cylinder of the engine is installed.

As an example of such an EGR control valve, as shown in FIG. 9, a double poppet valve (hereinafter referred to as an EGR valve) that reciprocates in the axial direction of the housing 101, the first and second poppet valve bodies 102 and the valve shaft 103. And an electric actuator 104 that opens and closes the EGR valve is known (for example, see Patent Document 1).
The valve body of the housing 101 is provided with a flow path 105 through which EGR gas flows and two first and second seats 106 provided around the flow path 105. In addition, the bearing portion 107 of the housing 101 is provided with a bearing hole 108 that opens from the flow path wall surface of the flow path 105 and extends from the flow path side opening to the back side opening.

  The EGR valve includes two first and second poppet valve bodies 102 that open and close the flow path 105 in contact with and away from the first and second seats 106 of the housing 101, and the first and second poppet valve bodies 102. It has the one valve shaft 103 connected so that integral movement was possible. The valve shaft 103 is supported by a bearing portion 107 of the housing 101 through a cylindrical bearing member 111 so as to be reciprocally movable in the axial direction.

  Further, a seal member 112 is provided in the bearing hole 108 on the flow path side with respect to the bearing member 111. Further, on the flow path side of the seal member 112, a filter 114 is provided in which a wire mesh is housed and held in a cup-shaped (bottomed cylindrical shape) holder pipe 113 having one end opened and the other end closed. In addition, an insertion hole through which the valve shaft 103 of the EGR valve is reciprocally moved is provided at the bottom of the holder pipe 113. The housing 101 is provided with a return spring 115 that urges the EGR valve in the valve closing (full closing) direction with respect to the valve shaft 103.

[Conventional technical problems]
By the way, when the engine is in operation such that the engine opens the EGR control valve and the EGR valve opens, the passage 105 of the housing 101 passes through the exhaust particles (combustion residue, carbon particles, etc.). Particulate matter: PM) and EGR gas containing liquid components such as unburned fuel flow.
Therefore, the PM contained in the high-temperature EGR gas flowing through the flow path 105 adheres to the surfaces of the EGR valve, particularly the first and second poppet valve bodies 102 and the valve shaft 103, using a liquid component such as unburned fuel as a binder. As a result, a deposit (hereinafter, deposit) may be formed.

  Here, in the EGR control valve of Conventional Example 1, when the EGR control valve is opened, the first and second poppet valve bodies 102 are separated from the first and second seats 106 to open the flow path 105. The intermediate portion of the valve shaft 103 located in the bearing portion 107 and the filter 114 of the housing 101 moves into the flow path 105 from the insertion hole of the holder pipe 113 and is exposed to the high temperature EGR gas. Deposits adhere to the outer peripheral surface of the intermediate portion.

When the intermediate portion of the valve shaft 103 protruding into the flow path 105 returns to the holder pipe 113 and the filter 114 when the EGR control valve is closed, the deposit attached to the intermediate portion of the valve shaft 103 is removed from the filter 114. It is to be collected (captured).
However, deposits deposited and deposited on the valve shaft 103 of the EGR valve under a high temperature environment of the engine EGR (exhaust) system may have high adhesiveness, and are not collected by the filter 114 but are collected on the valve shaft 103. If the EGR valve is closed while deposit is attached, the deposit may enter the bearing hole 108 of the bearing portion 107.

Therefore, it is conceivable to add a deposit removing function (scraping function) for scraping the deposit adhering to the valve shaft 103 of the EGR valve when the EGR valve is reciprocated (opened / closed) to the filter 114 of the EGR control valve of Conventional Example 1. .
Thus, when the deposit removing function is added to the filter 114, it is necessary to make the contact force between the valve shaft 103 of the EGR valve and the filter 114 stronger than the current one. When the contact force between the valve shaft 103 and the filter 114 is increased in this way, a large sliding resistance is obtained when the EGR valve is reciprocated (opened / closed) in the axial direction, and the valve shaft 103 of the EGR valve and the filter 114 are increased. There is a possibility that the sliding characteristics between the two will deteriorate.

International Publication No. 2010/018650

  The purpose of the present invention is to increase the contact force between the valve shaft of the valve and the filter to increase the deposit scraping effect by the filter, while reducing the sliding resistance of the valve shaft against the filter to prevent malfunction of the valve ( An object of the present invention is to provide an exhaust control valve that can be suppressed.

According to the invention described in claim 1 (exhaust control valve), a wire mesh structure (shaped) filter made of a material having a larger linear expansion coefficient than the valve stem and pipe of the valve is used. A valve shaft made of a small material and a pipe made of a material having a smaller linear expansion coefficient than the filter are arranged so as to close a filling space between the outer surface of the valve shaft of the valve and the inner surface of the pipe. The valve shaft is formed of a first metal having a linear expansion coefficient substantially the same as that of the pipe, and the filter is formed of a second metal that is more excellent in low temperature shrinkage and high temperature expansion than the first metal. Yes. As a result, the contact force between the filter and the valve shaft increases with the thermal expansion of the filter under a relatively high temperature environment due to the difference in linear expansion coefficient between the filter and the valve shaft and the pipe of the valve. In addition, when the usage environment is a relatively low temperature environment, an effect of reducing the contact force between the filter and the valve shaft can be obtained.

  Also, in the high temperature environment of the exhaust system of the internal combustion engine, the deposit adhering to the valve shaft of the valve has a property of softening at a high temperature, so that the deposit is combined with the effect of increasing the contact force between the filter and the valve shaft. A large deposit scraping effect can be obtained only at high temperatures when softening. Moreover, since the effect of reducing the contact force between the filter and the valve shaft is obtained at a low temperature when the deposit is cured, the sliding resistance of the valve shaft of the valve can be reduced. Therefore, since the reciprocating motion in the axial direction of the valve shaft with respect to the filter becomes good, the occurrence of valve malfunction can be suppressed.

It is sectional drawing which showed the shaft bearing part of the EGR control valve (Example 1). (Example 1) which was the top view which showed the EGR control valve of the state which removed the sensor cover. It is sectional drawing which showed the EGR control valve (Example 1). It is sectional drawing which showed the EGR control valve (Example 1). It is the perspective view which showed the poppet valve assembly and the electric actuator (Example 1). It is the perspective view which showed the poppet valve assembly and the electric actuator (Example 1). (A) is an explanatory view showing the effect of reducing sliding resistance when the use environment of the EGR control valve is relatively low, such as immediately after the engine is started, and (b) is the use of the EGR control valve as during engine operation. It is explanatory drawing which showed the deposit scraping effect when an environment is comparatively high temperature (Example 1). (A) is sectional drawing which showed the surrounding structure of the EGR valve at the time of valve closing, (b) is sectional drawing which showed the surrounding structure of the EGR valve at the time of valve opening (Example 1). It is sectional drawing which showed the EGR control valve (conventional example 1).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Configuration of Example 1]
1 to 8 show an EGR control valve (Embodiment 1) used in an EGR system to which the present invention is applied.

An internal combustion engine control device (engine control system) according to the present embodiment includes an exhaust gas (exhaust gas) from an exhaust pipe of an internal combustion engine (engine) such as a diesel engine for traveling on a vehicle mounted on a vehicle such as an automobile. An exhaust gas recirculation device (exhaust device for an internal combustion engine: hereinafter referred to as an EGR system) that recirculates (recirculates) EGR gas, which is a part of the EGR gas, is provided.
An intake duct (intake pipe) that forms an intake passage through which intake air (new air) or EGR gas that has passed through the air cleaner flows is connected to an intake port of each cylinder of the engine via an intake manifold. Further, an exhaust duct (exhaust pipe) that forms an exhaust passage through which exhaust gas discharged from a combustion chamber formed in each cylinder of the engine flows is connected to an exhaust port of each cylinder of the engine via an exhaust manifold. Yes.

The EGR system includes an EGR gas pipe that recirculates EGR gas from the engine exhaust system to the engine intake system. In the EGR gas pipe, an EGR gas flow path (described later) is formed for allowing EGR gas to flow from the exhaust manifold or the exhaust passage in the exhaust pipe to the intake manifold or the intake passage in the intake pipe. The EGR gas pipe is provided with an exhaust gas recirculation control valve (hereinafter referred to as EGR control valve) that variably controls (adjusts) the flow rate of the EGR gas flowing through the EGR gas flow path.
Here, the EGR system is used as an EGR valve control device (EGR control device for an internal combustion engine) that controls opening and closing of a poppet valve (poppet type EGR valve: hereinafter referred to as EGR valve) of an EGR control valve based on the operating state of the engine. .

The EGR control valve includes a housing 1 in which an EGR gas flow path is formed, a poppet valve assembly that is accommodated in the housing 1 so as to be reciprocally movable, and the poppet valve assembly is opened and closed in the axial direction of the EGR valve. And an electric actuator.
The poppet valve assembly is integrated with the EGR valve (valve body 2, valve shaft 3) that opens and closes the EGR gas passage in the housing 1, the return spring 4 that urges the EGR valve in the valve closing direction, and the valve shaft 3. And a scotch yoke 5 having a U-shaped cross section (or a rectangular cross section) connected in a movable manner.

The EGR valve includes an annular valve body 2 that is accommodated in the valve body 6 of the housing 1 so as to be reciprocally movable, and a valve shaft 3 that is accommodated in the shaft bearing portion 7 of the housing 1 so as to be reciprocally movable. ing.
The valve body 2 is a poppet valve body that opens and closes (changes the opening area) an EGR gas flow path formed in the valve body 6 by contacting and separating from the valve seat 11 assembled to the valve body 6.
The valve shaft 3 is a valve shaft that is connected to the valve main body 2 so as to be movable together and extends straight in the axial direction of the EGR valve (valve operating direction, reciprocating direction). The valve body 2 is supported and fixed on the outer periphery of one end portion (tip portion) of the valve shaft 3 in the axial direction. A scotch yoke 5 is coupled and fixed to the outer periphery of the other end portion (base end portion) of the valve shaft 3 in the axial direction.

The housing 1 accommodates a valve body 2, a valve body 6 having an EGR gas flow passage formed therein, a cylindrical (or rectangular tube) shaft bearing portion 7 that accommodates the valve shaft 3, and the like. Provided.
The housing 1 also includes a motor case 8 that houses and holds the motor M, a gear case 9 that houses a speed reduction mechanism (hereinafter referred to as a gear train) that reduces the rotation of the motor M by two steps and transmits it to the output member. Provided.
Here, the gear case 9 has an accommodation recess (a gear to be described later) for accommodating an electric actuator, particularly a gear train, etc., between the sensor cover 10 on which a rotation angle sensor (not shown) as an EGR valve opening sensor is mounted. Containment chamber).

An annular valve seat 11 on which the valve body 2 can be seated is press-fitted and fixed to the inner periphery of the partition wall (partition portion) of the valve body 6, that is, the flow passage wall surface of the constricted portion of the EGR gas flow passage. The shaft bearing portion 7 has a first bearing hole (hereinafter referred to as a bearing hole) 12 through which the valve shaft 3 penetrates in the axial direction. In the bearing hole 12, a bearing component for supporting the valve shaft 3 so as to be slidable in the axial direction is provided. This bearing component is held and fixed to the inner periphery of the shaft bearing portion 7, that is, the hole wall surface of the bearing hole 12. As bearing parts, a metal bearing (first bearing member) 13, a seal member 14, a baffle 15 and a wire mesh filter (hereinafter referred to as a filter) 16 are used.
Details of the valve body 6, the shaft bearing portion 7 and the bearing parts of the housing 1 will be described later.

Next, details of the EGR valve used in the EGR control valve of the present embodiment will be briefly described with reference to FIGS.
The EGR control valve of the present embodiment is in a fully closed (valve closed) state in which the valve body 2 is seated on the valve seat (seat edge) of the valve seat 11 of the valve body 6 and the flow path hole 18 which is a valve hole is closed (valve closed). 8), when the motor M is energized, the power (opening force) of the electric actuator is applied to the valve body 2 via the scotch yoke 5 and the valve shaft 3, so that the valve body 2 is connected to the EGR from the inlet port. The flow path hole 18 is opened by a predetermined valve lift amount toward the flow path hole 17 side, which is an inlet side flow path into which gas flows, that is, upstream of the EGR gas (exhaust) flow direction. The poppet type EGR valve is used.

As described above, the EGR valve is configured by the valve body 2 and the valve shaft 3.
The valve body 2 is made of a heat-resistant metal such as stainless steel. The valve body 2 is a valve head that closes and opens the EGR gas flow path (inlet port → flow path holes 17 to 19 → outlet port) by contacting and separating from the valve seat 11 of the valve body 6.

  Further, a frustoconical valve seal surface (valve face) that can be seated on the seat edge of the valve seat 11 is integrally provided on the outer peripheral portion of the valve body 2. In addition, a fitting hole that fits to the outer periphery of the tip end of the valve shaft 3 in the axial direction is integrally provided in the central portion of the valve body 2. The valve body 2 is welded and fixed to the outer periphery of the tip end of the valve shaft 3 in the axial direction using, for example, welding means such as arc welding (TIG welding, resistance welding) or laser welding.

The valve shaft 3 is formed of a heat-resistant metal (first metal) such as stainless steel having substantially the same linear expansion coefficient as that of the baffle 15, for example. That is, the valve shaft 3 is made of a material having a smaller linear expansion coefficient than the filter 16.
The valve shaft 3 is a valve stem that reciprocates in the axial direction of the EGR valve in conjunction with the rotational displacement of the output member. Further, the valve shaft 3 extends straight in the axial direction from the base end side located on the back side of the bearing hole 12 of the housing 1 toward the tip end side protruding into the flow path hole 19. Further, the valve shaft 3 is fitted (accommodated) in the bearing hole 12 of the shaft bearing portion 7 so as to be reciprocally movable.
Note that a poppet type EGR valve in which the valve body 2 and the valve shaft 3 are formed as an integral part may be used.

The valve shaft 3 includes first and second projecting shaft portions 21 and 22 on both sides in the axial direction thereof.
Between the first and second projecting shaft portions 21 and 22, an intermediate shaft portion 23 disposed in the bearing hole 12 of the shaft bearing portion 7 is provided.
The first protruding shaft portion 21 is provided on one end side (tip end side) of the valve shaft 3 in the axial direction, protrudes from the opening 24 on the flow path side of the bearing hole 12 into the flow path hole 19, and extends from the flow path hole 19. The valve seat 11 is configured to pass through the flow path hole 18 and protrude into the flow path hole 17.
A coupling shaft portion that couples and fixes the valve main body 2 by welding is provided on the outer periphery (tip outer periphery) on the distal end side of the first protruding shaft portion 21. Thereby, the valve body 2 and the valve shaft 3 are connected so as to be movable together.

The second projecting shaft portion 22 is provided on the other end side (base end side) of the valve shaft 3 in the axial direction, and accommodates the actuator from the opening 25 on the back side of the bearing hole 12 and the opening of the sliding hole of the metal bearing 13. Project into the chamber 26. The second projecting shaft portion 22 is press-fitted into a fitting portion (described later) of the scotch yoke 5 after its base end portion passes through a through-hole penetrating the central portion of the annular spring seat 27. Has been. The proximal end portion of the second protruding shaft portion 22 has an outer diameter smaller than that of the second protruding shaft portion 22 on the intermediate shaft portion 23 side.
An annular step (locking portion, annular step surface) capable of locking the locked portion (inner peripheral portion) of the spring seat 27 is provided on the outer periphery of the second protruding shaft portion 22. .
The base end portion of the second projecting shaft portion 22 of the valve shaft 3 may be coupled and fixed by caulking the fitting portion of the scotch yoke 5 or using a coupling means such as arc welding or laser welding. Further, the valve shaft 3 and the scotch yoke 5 may be formed as an integral part.

The return spring 4 is installed so as to surround the shaft bearing portion 7 of the housing 1 and the second projecting shaft portion 22 of the valve shaft 3 in a spiral manner. The return spring 4 is a coiled compression spring that generates an elastic force that urges the EGR valve in the valve closing (fully closed) direction with respect to the valve shaft 3.
The return spring 4 is a coil portion spirally wound between the spring seat portion of the spring seat 27 and the spring seat portion of the bottom portion of the housing 1 (the bottom portion of the cylindrical groove 28 on the outer peripheral side of the shaft bearing portion 7). have.
The inner peripheral portion of the spring seat 27 is sandwiched between the illustrated lower end surface of the fitting portion of the scotch yoke 5 and the annular step surface of the second protruding shaft portion 22. Thereby, the spring seat 27 is connected (fixed) to the valve shaft 3 so as to be movable together.

Next, details of the electric actuator of the present embodiment will be briefly described with reference to FIGS.
The electric actuator of the present embodiment, when supplied with electric power, decelerates the rotation of the motor M that generates rotational power (driving torque) that reciprocates (opens and closes) the EGR valve and the motor shaft 29 of the motor M by two stages. Then, the gear train (deceleration mechanism) that transmits to the output shaft (described later) and the rotational reciprocating (rotating) motion of the output gear (described later) of this gear train are converted into the linear reciprocating motion of the EGR valve (the axial direction of the EGR valve). An output member configured to include a part of the speed reduction mechanism and the conversion mechanism, and outputs the drive torque of the motor M to the yoke side, and the rotation of the output member. A rotation angle detection device for detecting the angle.

The gear train is a synthetic resin or metal pinion gear (input gear, motor gear) 31 fixed to the outer periphery of the motor shaft 29 of the motor M, and a synthetic resin or metal intermediate that rotates in mesh with the pinion gear 31. A gear 32, an output gear (valve gear) 33 made of synthetic resin that rotates in mesh with the intermediate gear 32, an intermediate valve shaft 34 that is arranged in parallel with the motor shaft 29, and a motor shaft 29 and the intermediate valve shaft 34 that are arranged in parallel. The output shaft 35 is provided.
Here, the intermediate gear 32 is rotatably fitted to the outer periphery of the intermediate valve shaft 34. The intermediate gear 32 is formed with a large-diameter gear (intermediate gear teeth) 36 that meshes with the pinion gear 31 and a small-diameter gear (intermediate gear teeth) 37 that meshes with the output gear 33.

The output member transmits the driving torque of the motor M to the EGR valve via the Scotch yoke 5. The output member includes an output gear 33 that rotates in response to the driving torque of the motor M, an output shaft 35 that is installed on the rotation center axis of the output gear 33 and is connected to the output gear 33 so as to be integrally rotatable, An output lever 41 connected to the output shaft 35 so as to be integrally rotatable, an eccentric pin (hereinafter referred to as a pivot pin) 42 held at a protruding end of the output lever 41, and an outer periphery of the pivot pin 42 are rotatably supported. Ball bearings (follower) 43, dual ball bearings (second bearing members) 45 and 46 that support the output shaft 35 so as to be slidable in the rotation direction, and outer circumferences of these double ball bearings 45 and 46 And a cylindrical collar 47 which is press-fitted and fixed to the main body.
The cylindrical collar 47 is not shown in FIG. Further, the cylindrical collar 47 may not be provided.

A hollow cylindrical boss 51 is integrally formed on the inner peripheral portion of the output gear 33 of the gear train. Further, the output gear 33 has a partially cylindrical (fan-shaped) tooth forming portion 52 on the outer side in the radial direction from the cylindrical boss 51. On the outer periphery of the tooth forming portion 52, output gear teeth 53 that mesh with the intermediate gear teeth 37 are formed in a fan shape by a predetermined angle.
A metal plate 54 is insert-molded in the output gear 33 so as to close the opening on one end side (valve side) of the cylindrical boss 51. In the central portion of the metal plate 54, a fitting hole having a two-surface width (a structure for preventing the output shaft 35 from rotating idly and a rotation preventing structure) is formed through. In the fitting hole, the fitting shaft portion 55 of the output shaft 35 is fitted and fixed in a state where the fitting shaft portion 55 is prevented from rotating. Thereby, the output gear 33 and the output shaft 35 are connected so as to be integrally rotatable.

The output shaft 35 includes first and second projecting shaft portions on both sides in the rotational axis direction. An intermediate shaft portion is provided between the first and second protruding shaft portions.
The first projecting shaft portion is provided with a fitting shaft portion 55 having a two-surface width. The fitting shaft portion 55 may have a quadrangular cross section.
The second protruding shaft portion has a circular cross section. In addition, you may provide 2 surface width in a 2nd protrusion shaft part.
The inner rings of the double ball bearings 45 and 46 are fitted and held on the outer periphery of the intermediate shaft portion of the output shaft 35 by press fitting. The intermediate shaft portion of the output shaft 35 is rotatably disposed in a bearing hole of a shaft bearing portion (bearing holder) 56 of the gear case 9 of the housing 1.

The conversion mechanism includes a scotch yoke 5, an output lever 41, a pivot pin 42, a follower 43, and the like.
The scotch yoke 5 is accommodated in the actuator accommodating chamber 26. The scotch yoke 5 has a fitting portion 57 coupled to the outer periphery of the second protruding shaft portion 22 of the valve shaft 3. Thereby, the valve shaft 3 and the scotch yoke 5 are connected so as to be movable together. The scotch yoke 5 receives the driving torque of the motor M from the pivot pin 42 via the follower 43 and reciprocates in the axial direction of the valve shaft 3.
Further, a yoke groove 58 into which the follower 43 is slidably inserted is formed in the scotch yoke 5.

The output lever 41 is a link lever that drives and connects the output shaft 35, the pivot pin 42 and the follower 43, and transmits the driving torque of the motor M to the pivot pin 42 and the follower 43. The output lever 41 is disposed in the actuator housing chamber 26.
The base end portion of the output lever 41 is provided with a first fitting hole for press-fitting so that the second protruding shaft portion of the output shaft 35 penetrates in the axial direction thereof. Further, a second fitting hole is provided at the tip of the output lever 41. The second fitting hole is provided at a position eccentric from the rotation center axis of the second protruding shaft portion of the output shaft 35 by a predetermined distance.

  The pivot pin 42 is driven into the second fitting hole of the output lever 41 and is press-fitted and fixed to the distal end portion (output portion) of the output lever 41. The pivot pin 42 is inserted into the yoke groove 58 of the scotch yoke 5 together with the follower 43. Further, the pivot pin 42 projects into the actuator housing chamber 26 from the opening of a bearing hole (described later) of the shaft bearing portion of the gear case 9 and the end surfaces of the double ball bearings 45 and 46.

The follower 43 is housed in the actuator housing chamber 26 together with the scotch yoke 5. The follower 43 is rotatably supported on the outer periphery of the pivot pin 42 and is slidably (rolled) into the yoke groove 58 of the scotch yoke 5. Further, the follower 43 is provided at a position eccentric from the rotation center axis of the second projecting shaft portion of the output shaft 35 by a predetermined distance. Further, the follower 43 is connected to the output shaft 35 via the output lever 41 and the pivot pin 42 so as to be integrally rotatable.
The actuator housing chamber 26 formed outside the housing 1 houses functional components such as the return spring 4, the conversion mechanism, and the spring seat 27.

Here, the motor M which is a power source of the electric actuator is electrically connected to an external power source (battery) via a motor drive circuit electronically controlled by an engine control unit (electronic control unit: hereinafter referred to as ECU). .
The ECU includes a microcomputer having a known structure including functions of a CPU, a memory (ROM, RAM, EEPROM, etc.), an input circuit (input unit), an output circuit (output unit), a power supply circuit, and a timer circuit. Is provided.

Here, when the ignition switch is turned on (IG / ON), the ECU first outputs various sensor output signals necessary to calculate (calculate) the engine operating status (engine information) or operating conditions (state). Is configured to acquire (input).
Output signals (electrical signals) from various sensors are A / D converted by an A / D conversion circuit and then input to an input unit of a microcomputer. This microcomputer has not only a rotation angle sensor but also an air flow meter, a crank angle sensor, an accelerator opening sensor, a throttle opening sensor, an intake air temperature sensor, a water temperature sensor, and an exhaust gas sensor (air-fuel ratio sensor, oxygen concentration sensor) ) Etc. are connected.

The rotation angle detection device includes a cylindrical magnetic circuit unit installed so as to be rotatable integrally with the output member, and valve position information (valve opening degree, stroke amount) of the EGR control valve by measuring the rotation angle of the magnetic circuit unit. And a change in the relative rotation angle between the magnetic circuit unit and the rotation angle sensor is detected by a magnetic change applied to the rotation angle sensor from the magnetic circuit unit.
The magnetic circuit unit is fixed to the inner periphery of the cylindrical boss 51 of the output gear 33 with an adhesive or the like. The magnetic circuit section includes a pair of partial cylindrical sensor yokes 61 that are divided into two in the diameter direction of the cylindrical boss 51, and a pair of sensor magnets that are arranged with the magnetic poles facing in the same direction between the divided sections of the sensor yoke 61. (Magnet) 62 is provided.
When the cylindrical boss 51 of the output gear 33 is made of synthetic resin, the magnetic circuit portion may be insert-molded on the cylindrical boss 51.

The rotation angle sensor is sandwiched and held between opposing portions of a pair of stator cores installed in the sensor mounting portion of the sensor cover 10. This rotation angle sensor is mainly composed of a Hall IC that outputs an output signal (analog voltage signal) corresponding to the magnetic flux density interlinking the magnetic sensing surface of the semiconductor Hall element to the ECU.
Instead of the Hall IC, a non-contact type magnetic detection element such as a Hall element alone or a magnetoresistive element may be used.

Next, details of the housing 1 of the present embodiment will be briefly described with reference to FIGS.
As described above, the housing 1 of this embodiment includes the valve body 6, the shaft bearing portion 7, the motor case 8, and the gear case 9.
The upstream end surface of the valve body 6 is provided with a flange-like coupling flange 63 that is coupled to the coupling end surface of the branch portion of the exhaust pipe or the coupling flange of the EGR gas pipe by screw fastening using a plurality of screws.
Further, on the downstream end face of the valve body 6, a flange-like coupling flange 64 is provided that is coupled to the coupling end surface of the coupling portion of the intake pipe or the coupling flange of the EGR gas pipe by screw fastening using a plurality of screws. .
These coupling flanges have coupling end faces that are attached to engine-side (vehicle-side) fixing members such as an exhaust pipe branch or an intake pipe merging section. As a result, the EGR control valve is fixed to the engine-side (vehicle-side) fixing member.

  An EGR gas flow path (flow path holes 17 to 19) is formed inside the valve body 6. Further, the valve body 6 has an EGR gas flow path from a first flow path (inlet side flow path: flow path hole 17) located upstream of the valve seat 11 in the exhaust flow direction and from the valve seat 11. In addition, an annular (cylindrical) partition wall (partition portion) is formed which is partitioned into a second flow path (exit-side flow path: flow path hole 19) located on the downstream side in the exhaust flow direction.

The outer periphery of the valve seat 11 having a rectangular cross section is press-fitted and fixed to the inner peripheral portion of the partition wall of the valve body 6. An annular valve seat on which the EGR valve can be seated is provided at the seat edge of the valve seat 11. Further, a flow path hole (valve hole) 18 through which the EGR gas passes is formed inside the valve seat 11.
The first flow path (flow path hole 17) is an inlet flow path through which EGR gas flows from an inlet port (flow path inlet) opened at the upstream end face of the valve body 6.
The flow path hole 18 is a valve hole (communication hole) that is provided so as to penetrate the central portion of the valve seat 11 and communicates the flow path hole 17 and the flow path hole 19.
The second flow path (flow path hole 19) is an outlet flow path that guides the EGR gas that has flowed from the flow path hole 18 to an outlet port that is open at the downstream end face of the valve body 6.

The shaft bearing portion 7 is a cylindrical first bearing holder that holds the outer ring portion of the metal bearing 13. The shaft bearing portion 7 is disposed so as to surround the metal bearing 13 in the circumferential direction.
Inside the shaft bearing portion 7 is formed a bearing hole 12 that opens at the flow path wall surface of the flow path hole 19 and extends straight from the flow path side opening 24 to the back side opening 25 in the axial direction of the valve shaft 3. ing. The valve shaft 3 is fitted into the bearing hole 12 so as to be capable of reciprocating in the axial direction.
In addition, an opening 24 on the flow path side that is opened on the flow path wall surface of the flow path hole 19 is formed on one end side (flow path hole side, flow path side) of the bearing hole 12 in the axial direction.
In addition, an opening 25 on the back side opened by the wall surface of the actuator housing chamber 26 is formed on the other end side in the axial direction of the bearing hole 12 (opposite side and back side with respect to the flow path hole side).

The shaft bearing portion 7 is formed in a cylindrical shape so as to surround the metal bearing 13 in the circumferential direction. The shaft bearing portion 7 includes an annular first step having a function as a first restricting portion for restricting the press-fit fixing position of the metal bearing 13 and a second restricting portion for restricting the press-fit fixing position of the seal member 14. An annular second step having the function is provided.
The bearing hole 12 has a bearing press-fitting hole for press-fitting the outer ring part of the metal bearing 13, a seal press-fitting hole for press-fitting the outer ring part of the seal member 14, and a cylindrical shape that holds the outer periphery of the baffle 15. The receiving hole (pipe press-fitting hole) is provided.

A concave motor housing chamber 59 for housing the motor M is formed inside the motor case 8. The opening of the motor case 8 is closed by the front bracket 65 of the motor M.
A gear housing chamber 60 for housing a gear train is formed inside the gear case 9. The opening of the gear case 9 is closed with a sensor cover 10. Further, a flange-like coupling flange 66 that is coupled to the coupling end surface of the sensor cover 10 by screw fastening is provided on the opening periphery of the gear case 9.

A cylindrical shaft bearing portion 56 that holds the outer ring portion of the double ball bearings 45 and 46 and the cylindrical collar 47 is integrally formed in the gear case 9. The shaft bearing portion 56 is disposed so as to surround the double ball bearings 45 and 46 and the cylindrical collar 47 in the circumferential direction.
The shaft bearing portion 56 is a second bearing holder that holds the outer ring portion of the cylindrical collar 47 or the outer ring of the double ball bearings 45 and 46. A second bearing hole (hereinafter referred to as a bearing hole) into which the output shaft 35 is rotatably inserted is provided in the shaft bearing portion 56. The bearing hole has a press-fitting hole in which the outer ring portion of the cylindrical collar 47 is press-fitted and fixed. The actuator housing chamber 26 formed between the shaft bearing portions 7 and 56 of the housing 1 is a synthetic resin that is coupled to the coupling portion of the valve body 6 or the coupling portion of the gear case 9 by screw fastening using a plurality of screws. Alternatively, it is closed by a metal case cover 67.

The sensor cover 10 is made of synthetic resin. The sensor cover 10 is provided with a flange-like coupling flange 69 that is coupled to the coupling end surface of the coupling flange 64 of the gear case 9 by screw fastening using a plurality of screws 68.
The sensor cover 10 includes a pair of brush terminals projecting outward from the front bracket 65 of the motor M and an internal connection connector (not shown) for electrical connection between the pair of motor terminals and a pair of first terminals. An external connection connector (not shown) is provided for electrical connection between the first and second motor terminals and the plurality of sensor terminals and an external circuit (ECU or battery).

Next, details of the metal bearing 13 of the present embodiment will be briefly described with reference to FIGS.
The metal bearing 13 is a cylindrical sintered oil-impregnated bearing (cylindrical sliding bearing, metal bush) formed of a sintered material, having a large number of pores therein, and impregnating the internal pores with lubricating oil, A large number of internal pore openings (surface pores) are formed on the hole wall surface (inner peripheral surface) of the sliding hole. The metal bearing 13 penetrates into the internal pores by negative pressure due to linear movement in the forward direction (opening direction) or backward direction (valve closing direction) of the valve shaft 3 inserted into the sliding hole. The lubricating oil oozes out from the opening of the sliding surface (inner peripheral surface) with the valve shaft 3 to form an oil film on the sliding portion between the inner peripheral surface of the metal bearing 13 and the outer peripheral surface of the valve shaft 3. The valve shaft 3 is supported by the oil film so as to be reciprocally movable.

The metal bearing 13 supports the valve shaft 3 so as to be slidable in the moving direction. Inside the metal bearing 13 is formed a through hole that supports the outer peripheral surface of the valve shaft 3 so as to be slidable in the moving direction. A sliding clearance for smooth reciprocation of the valve shaft 3 is provided between the outer peripheral surface of the valve shaft 3 and the inner peripheral surface of the metal bearing 13.
The metal bearing 13 has a cylindrical outer ring portion that is press-fitted and fixed to the wall surface of the bearing press-fitting hole of the shaft bearing portion 7. The outer peripheral portion of the outer ring portion is used as a press-fit fixing portion that is hermetically press-fitted and fixed to the bearing press-fit hole of the shaft bearing portion 7. Further, the outer ring portion is in contact with the first step of the shaft bearing portion 7, thereby restricting the press-fitting and fixing position of the metal bearing 13.

Next, details of the seal member 14 of this embodiment will be briefly described with reference to FIGS. The seal member 14 is a hermetic seal reinforced by, for example, an L-shaped metal reinforcing ring 71 and an I-shaped metal reinforcing ring 72, and is a synthetic rubber capable of elastic deformation in the radial direction and the thrust direction of the valve shaft 3. A seal rubber (elastically deformable portion) 73 is provided.
The seal member 14 is accommodated in a seal press-fitting hole on the flow path side of the bearing hole 12 relative to the metal bearing 13 so as to surround the periphery of the valve shaft 3 in the circumferential direction. This is an airtight seal member that hermetically seals between the hole wall surface and the outer peripheral surface of the valve shaft 3.

The metal reinforcing rings 71 and 72 have a cylindrical outer ring portion that is press-fitted and fixed to the wall surface of the seal press-fitting hole of the bearing hole 12 of the shaft bearing portion 7. The outer peripheral portion of the outer ring portion is used as a press-fit fixing portion that is press-fit and fixed in a fluid-tight manner into the seal press-fit hole of the bearing hole 12. Further, the outer ring portion is in contact with the second step of the shaft bearing portion 7, thereby restricting the press-fitting and fixing position of the seal member 14.
The seal rubber 73 is made of a synthetic rubber such as fluorine rubber, nitrile rubber or acrylic rubber having good slidability.
The seal rubber 73 is a gasket (dust seal) that hermetically seals an annular gap formed between the inner periphery of the shaft bearing portion 7 of the valve body 6 and the outer periphery of the intermediate shaft portion 23 of the valve shaft 3. It has a function.

The seal rubber 73 is installed inside the shaft bearing portion 7 of the valve body 6 so as to surround the periphery of the intermediate shaft portion 23 of the valve shaft 3 in the circumferential direction.
The seal rubber 73 is formed in, for example, an L-shape, and an annular portion that surrounds the periphery of the intermediate shaft portion 23 of the valve shaft 3 in the circumferential direction, and obliquely protrudes toward the valve shaft 3 from the inner periphery of the annular portion. And an annular sealing lip. Although this seal lip contacts the outer peripheral surface (sliding surface) of the intermediate shaft portion 23 of the valve shaft 3, the shaft can slide.

Next, details of the baffle 15 of the present embodiment will be briefly described with reference to FIGS.
The baffle 15 has a cup shape (bottomed cylindrical shape) that is open at one end and closed at the other end, and foreign matters (including PM and deposits) contained in the EGR gas flowing through the flow path hole 19 are the bearing holes 12. A cup baffle that suppresses entry into the inside. The baffle 15 is formed of a first metal such as thin stainless steel having a linear expansion coefficient substantially the same as that of the valve shaft 3, for example. That is, the baffle 15 is made of a material having a smaller linear expansion coefficient than the filter 16.

The baffle 15 is installed between the outer peripheral surface of the intermediate shaft portion 23 of the valve shaft 3 and the inner peripheral surface of the shaft bearing portion 7 (hole wall surface of the bearing hole 12). The baffle 15 is held on the flow path side of the bearing hole 12 relative to the metal bearing 13 and the seal member 14, and partially enters the flow path hole 19 from the bearing hole 12 through the opening 24 on the flow path side of the bearing hole 12. Is installed to protrude.
The baffle 15 includes a hollow cylindrical holder pipe 81 that covers the periphery of the intermediate shaft portion 23 of the valve shaft 3 with a cylindrical (or rectangular tube) filling space 80 and an opening 24 on the flow path side of the bearing hole 12. An annular (or angular) cover 82 is provided.

The holder pipe 81 has a predetermined plate thickness and is extended in the axial direction so as to follow the outer peripheral surface of the intermediate shaft portion 23 of the valve shaft 3. The holder pipe 81 has a pipe base end portion held in the bearing hole 12 of the shaft bearing portion 7, a pipe protruding portion that protrudes into the flow passage hole 19 from the opening 24 on the flow passage side of the bearing hole 12, and the like. ing.
The pipe base end portion has a cylindrical outer ring portion that is press-fitted and fixed to the wall surface of the pipe press-fitting hole of the bearing hole 12 of the shaft bearing portion 7 so as to contact the metal reinforcing rings 71 and 72 of the seal member 14. doing.
The pipe protrusion is exposed in the flow path hole 19 so as to be directly exposed to the high-temperature EGR gas flowing through the flow path hole 19, and suppresses the entry of foreign matter contained in the EGR gas into the bearing hole 12. It has a function as a baffle pipe.

The cover 82 has a predetermined plate thickness and is formed in an annular shape (or a rectangular ring shape) so as to surround the periphery of the intermediate shaft portion 23 of the valve shaft 3 in the circumferential direction. An insertion hole 83 is formed through the center of the cover 82 in the thickness direction. Further, the cover 82 is exposed in the flow path hole 19 so as to be directly exposed to the high-temperature EGR gas flowing through the flow path hole 19, so that foreign matter contained in the EGR gas can enter the bearing hole 12. It has a function as a baffle plate to suppress.
The insertion hole 83 passes through the cover 82 so as to communicate with the inside and outside of the cover 82, and is arranged so that the intermediate shaft portion 23 of the valve shaft 3 is inserted in the axial direction thereof.
A predetermined clearance is formed between the intermediate shaft portion 23 of the valve shaft 3 and the cover 82 so that the valve shaft 3 can reciprocate in the axial direction.

Next, details of the filter 16 of this embodiment will be briefly described with reference to FIGS.
The filter 16 has a wire mesh structure made of a material having a larger linear expansion coefficient than the valve shaft 3 and the baffle 15. The filter 16 is formed by filling a wire mesh obtained by knitting a fine metal wire (wire, fine metal wire) made of a second metal such as an aluminum alloy, which is excellent in low temperature shrinkage and high temperature expansibility, than the first metal into a filling space 80. It is filled and arranged.
The filter 16 is filled and disposed in the filling space 80 so as to block between the outer peripheral surface of the intermediate shaft portion 23 of the valve shaft 3 and the inner peripheral surface of the holder pipe 81 of the baffle 15.
The filling space 80 includes an axial space between the end faces of the metal reinforcing rings 71 and 72 and the seal rubber 73 of the seal member 14 and the inner surface of the cover 82, and an outer peripheral surface of the intermediate shaft portion 23 of the valve shaft 3 and the baffle 15. The holder pipe 81 has a radial space with the inner peripheral surface.

[Operation of Example 1]
Next, the operation of the EGR control valve used in the EGR system of this embodiment will be briefly described with reference to FIGS.
Here, FIG. 8A is a view showing a closed (fully closed) state in which the valve body 2 is seated on the valve seat 11 and closes the flow passage holes 17 to 19.
FIG. 8B shows a valve opening state in which the valve body 2 opens (lifts) from the valve seat 11 to the flow path hole 17 side by a predetermined valve lift amount to open the flow path holes 17 to 19. FIG.

The motor M that reciprocates the EGR valve of this embodiment is configured to be energized and controlled by the ECU.
Here, when the ignition switch is turned on (IG / ON), the ECU first outputs various sensor output signals necessary to calculate (calculate) the engine operating status (engine information) or operating conditions (state). Is obtained (input), and the motor M of the electric actuator is electronically controlled based on the operating state or operating conditions of the engine and the program stored in the ROM.

Here, in an operation situation where the power supply to the motor M is not performed (engine operation situation), the valve body 2 is seated on the seat edge (valve seat) of the valve seat 11 by the urging force of the return spring 4. The valve seat 11 is closed (fully closed) to close the flow path hole 18 (see FIG. 8A).
Therefore, the EGR gas flow path (flow) formed in the valve body 6 is closed by closing the flow path hole 18 which is a communication hole (valve hole of the EGR control valve) formed through the central portion of the valve seat 11. The passage holes 17 to 19) are closed. Thereby, EGR gas does not mix in clean intake air (fresh air) that has passed through the air cleaner (EGR cut).

Next, when the operation state (engine operation state) is such that the EGR control valve is opened, the EGR valve opens to a predetermined valve opening (valve lift amount or stroke amount) corresponding to the operation state. To open the valve.
Then, electric power (motor drive current or motor applied voltage) is supplied to the inner conductor (motor winding portion, armature coil, etc.) of the motor M, and the inner conductor of the motor M is opened in the valve opening direction (opening side of the EGR valve). Motor drive current flows. Therefore, the motor shaft 29 of the motor M rotates in the valve opening direction. As a result, the driving torque of the motor M is transmitted to the pinion gear 31, the intermediate gear 32, and the output gear 33.
Then, the output shaft 35 connected to the output gear 33 so as to rotate together with the output gear 33 rotates in the valve opening direction by a predetermined rotation angle as the output gear 33 rotates.

Then, the output lever 41 to which the drive torque is transmitted from the output shaft 35 rotates in the valve opening direction by a predetermined rotation angle (a rotation angle equal to the operation angle of the output gear 33) as the output shaft 35 rotates.
Here, the pivot pin 42 is attached to a protruding end portion of the output lever 41, that is, a position eccentric from the rotation center axis of the output shaft 35 by a predetermined radial distance. When the output shaft 35 and the output lever 41 are rotated, the follower 43 supported by the pivot pin 42 is brought into sliding contact with the groove side surface of the yoke groove 58 of the scotch yoke 5 when the output shaft 35 and the output lever 41 rotate. The rotational movement of the output shaft 35 and the output lever 41 is converted into a linear (reciprocating) movement of the valve shaft 3.

The valve shaft 3 and the scotch yoke 5 linearly move to the poppet valve body opening side (the opening side of the EGR valve) against the urging force of the return spring 4. At this time, since the valve shaft 3 is guided in the moving direction by the metal bearing 13 of the shaft bearing portion 7, the valve shaft 3 also moves linearly toward the poppet valve body opening side.
As the valve shaft 3 moves linearly, the valve body 2 connected to the valve shaft 3 so as to move integrally with the valve shaft 3 is detached from the valve seat 11 and is a predetermined valve lift amount corresponding to the operating state of the engine. By opening outward toward the flow path hole 17 side, the valve hole of the valve seat 11 is opened (see FIG. 8B).

Therefore, when the flow path hole 18 of the valve seat 11 is opened, the EGR gas flow path (flow path holes 17 to 19) formed in the valve body 6 is opened.
For this reason, the EGR gas that is a part of the exhaust gas flowing out from each cylinder of the engine passes through the EGR gas passage from the branch portion of the exhaust passage formed in the exhaust pipe, and the intake passage formed in the intake pipe It is recirculated to the confluence part. Thereby, EGR gas is mixed in the intake air supplied to each cylinder of the engine.
Thereby, harmful substances (for example, NOx) contained in the exhaust gas are reduced.

  At this time, when the EGR valve is closed, the intermediate shaft portion 23 of the valve shaft 3 is in the bearing hole 12, the seal member 14 or the baffle 15 of the shaft bearing portion 7 as shown in FIGS. The portion (portion shown by mesh in FIG. 8) A is located in the flow path from the insertion hole 83 of the baffle 15 by the stroke of the valve body 2 as shown in FIGS. 7 and 8B. Project into the hole 19. For this reason, the valve body 2, the first protruding shaft portion 21 of the valve shaft 3 and the intermediate shaft portion 23 protruding into the flow passage hole 19 are exposed to EGR gas flowing in the flow passage holes 17 to 19. As described above, deposits adhere to the outer peripheral surfaces of the valve body 2, the first projecting shaft portion 21 of the valve shaft 3, and the intermediate shaft portion 23.

Further, when the operation state (engine operation state) is such that the EGR control valve is fully closed (closed), electric power (motor drive current or motor applied voltage) is supplied to the inner conductor of the motor M, A motor drive current in the valve closing direction (the EGR valve closing side) flows through the conductor. Therefore, the motor shaft 29 of the motor M rotates in the valve closing direction.
As a result, the valve body 2 and the valve shaft 3 are driven to close to assist the urging force of the return spring 4 to close.
Therefore, when the flow path hole 18 of the valve seat 11 is closed, the EGR gas flow path (flow path holes 17 to 19) formed in the valve body 6 is closed. Thereby, EGR gas does not mix in clean intake air (fresh air) that has passed through the air cleaner (EGR cut).

At this time, as shown in FIGS. 7 and 8A, the portion A of the intermediate shaft portion 23 protruding into the flow passage hole 19 at the time of opening / closing of the EGR valve has a bearing hole 12, The seal member 14 or the baffle 15 is returned.
When passing through the insertion hole 83 of the baffle 15, the intermediate shaft portion protrudes from the outer peripheral surface of the intermediate shaft portion 23 rather than the clearance between the intermediate shaft portion 23 of the valve shaft 3 and the cover 82 of the baffle 15. The deposit attached to the outer peripheral surface of the baffle 23 is scraped off by the cover 82 of the baffle 15.
The remaining deposit is collected or captured by the filter 16 that is filled in the filling space 80.

  By the way, in the EGR control valve of this embodiment, since the linear expansion coefficient of the filter 16 is larger than the linear expansion coefficients of the valve shaft 3 and the baffle 15, the valve is operated when the environmental temperature is relatively high, that is, in a high temperature environment. The contact force of the filter 16 with respect to the outer peripheral surface of the intermediate shaft portion 23 of the shaft 3 increases (see the white arrow in FIG. 7B). That is, when the use environment of the EGR control valve is relatively high, such as during engine operation, the deposit scraping effect is obtained by the large contact force of the annular portion of the filter 16 with respect to the outer peripheral surface of the valve shaft 3. At this time, since the deposit attached to the valve shaft 3 is softened, the effect of scraping off the deposit by the annular portion of the filter 16 is increased.

  Therefore, the filter 16 filled in the filling space 80 of the baffle 15 held by the shaft bearing portion 7 has an annular portion that contacts the outer peripheral surface of the intermediate shaft portion 23 of the valve shaft 3. A scraping function for scraping off deposits adhering to the outer peripheral surface of the portion 23 is provided. In particular, even in the case of a deposit having high adhesiveness attached to the intermediate shaft portion 23 of the valve shaft 3 under the high temperature environment of the engine EGR system, the outer peripheral surface of the intermediate shaft portion 23 of the valve shaft 3 at the annular portion of the filter 16 Can be scraped off.

On the other hand, when the usage environment of the EGR control valve is relatively low, such as immediately after engine startup such as in cold weather, that is, in a low temperature environment, the contact force of the annular portion of the filter 16 with the outer peripheral surface of the valve shaft 3 is small (FIG. 7). (See the white arrow in (a)). At this time, the deposit adhering to the valve shaft 3 is cured (deposited and solidified), but the sliding resistance of the valve shaft 3 with respect to the annular portion of the filter 16 is reduced due to a decrease in the contact force of the annular portion of the filter 16.
Thereby, in the EGR control valve of the present embodiment, the sliding resistance between the filter 16 and the valve shaft 3 becomes smaller as the environmental temperature is lower.

[Effect of Example 1]
As described above, in the EGR control valve of the present embodiment, the valve between the outer peripheral surface of the valve shaft 3 made of a material having a smaller linear expansion coefficient than the filter 16 and the inner peripheral surface of the holder pipe 81 of the baffle 15 is provided. A wire mesh structure filter 16 made of a material having a larger linear expansion coefficient than the shaft 3 and the baffle 15 is disposed. In particular, a filter 16 having a wire mesh structure is filled in the filling space 80.

The valve shaft 3 is formed of a first metal (for example, stainless steel) having a linear expansion coefficient substantially the same as that of the baffle 15.
On the other hand, the filter 16 is formed of a second metal (for example, an aluminum alloy or the like) that is more excellent in low temperature shrinkage and high temperature expansion than the first metal. That is, the filter 16 has a wire mesh structure made of a material having a larger linear expansion coefficient than the valve shaft 3 and the baffle 15.

  As a result, when the deposit flows at a relatively high temperature, the contact force between the filter 16 and the valve shaft 3 increases with the thermal expansion of the filter 16 due to the difference in coefficient of linear expansion between the valve shaft 3 and the baffle 15 and the filter 16. The effect is obtained. That is, in the high temperature environment of the EGR system of the engine (temperature environment where the EGR valve is exposed to high temperature EGR gas), the deposit adhering to the valve shaft 3 has a property of softening at a high temperature. Along with the collecting effect, the deposit scraping effect can be obtained by a large contact force of the annular portion of the filter 16 at a relatively high temperature when the deposit is softened.

On the other hand, when the deposit is cured at a relatively low temperature, the effect of reducing the contact force between the filter 16 and the valve shaft 3 can be obtained due to the difference in coefficient of linear expansion between the valve shaft 3 and the baffle 15 and the filter 16. That is, since the contact force between the filter 16 and the valve shaft 3 is reduced in a low temperature environment immediately after the engine is started, the sliding resistance of the valve shaft 3 can be reduced.
Therefore, since the slidability between the valve shaft 3 and the filter 16 can be improved, the reciprocating motion of the valve shaft 3 in the axial direction with respect to the filter 16 is improved. Thereby, even when the deposit removing function for scraping off the highly adhesive deposit from the outer peripheral surface of the intermediate shaft portion 23 of the valve shaft 3 is added to the filter 16, it is possible to suppress the occurrence of malfunction of the EGR valve.

[Modification]
In this embodiment, as a motion direction conversion mechanism that converts the rotational reciprocating (rotating) motion of the output gear 33 or the output shaft 35 of the gear train into the linear reciprocating motion of the EGR valve (the reciprocating motion in the axial direction of the valve shaft 3). Although a conversion mechanism including the scotch yoke 5, the output lever 41, the pivot pin 42, the follower 43, and the like is employed, a conversion mechanism including a cam or a screw may be employed as the movement direction conversion mechanism.
In the present embodiment, as an actuator for opening and closing the EGR valve in its axial direction,
Although an electric actuator having a motor M, a gear train and a conversion mechanism is employed, an electromagnetic (solenoid) actuator or a fluid pressure actuator may be employed.

In this embodiment, the exhaust control valve of the present invention is applied to an EGR control valve used in an exhaust gas circulation device (EGR system) of an internal combustion engine. However, the exhaust control valve of the present invention is applied to an EGR system of an internal combustion engine. You may apply to the EGR cooler bypass valve etc. which are built in. Further, the present invention may be applied to a waste gate valve, a scroll flow path switching valve, an exhaust flow rate control valve, an exhaust pressure control valve, an exhaust flow path switching valve, an exhaust throttle valve, or the like incorporated in an exhaust system of an internal combustion engine.
Poppet-type EGR valves are used as the EGR control valve and exhaust control valve. However, a butterfly valve, flap valve, plate valve, rotary valve, etc. are provided through a conversion mechanism between the valve and the shaft. A rotary valve such as a valve may be employed. A double poppet valve may be employed.
Moreover, you may use the operating rod extended in an axial direction instead of the valve shaft 3 as a shaft (valve shaft).

Further, before assembling the output lever 41 to the second projecting shaft portion (output portion) 22 of the output shaft 35, the output lever 41, the pivot pin 42 and the follower 43 are assembled in advance, and these followers are unitized (sub-assembly). A subassembly may be configured, and the follower subassembly may be assembled to the second projecting shaft portion (output portion) 22 of the output shaft 35.
Further, instead of the follower 43 formed of a ball bearing, a follower roller that is rotatably supported on the outer periphery of a pivot pin (support shaft) 42 may be used.

  In this embodiment, as a valve of the EGR (exhaust) control valve, the valve main body 2 is moved from the closed (full closed) state in which the poppet valve body (valve main body 2) is seated on the valve seat 11 of the valve seat 11 of the housing 1. Is an open valve type poppet type that opens (lifts) by a predetermined valve lift amount toward a first flow path (flow path hole 17) formed upstream of the valve seat 11 in the exhaust flow direction. Although the EGR valve is adopted, the poppet valve body is used as a valve of the EGR (exhaust) control valve from the closed (fully closed) state where the poppet valve body is seated on the valve seat 11 of the valve seat 11 of the housing 1. A poppet type EGR of an inner opening valve type that opens (lifts) inward by a predetermined valve lift amount toward a second flow path (flow path hole 19) formed downstream of the valve seat 11 in the exhaust flow direction. Adopting a valve And it may be.

In the present embodiment, as the bearing hole of the shaft bearing portion 7 of the housing 1, the second flow located downstream of the valve seat 11 in the exhaust flow direction (for example, the intake passage side in the intake pipe of the internal combustion engine (engine)). A bearing hole 12 that is open at the flow path wall surface of the path (flow path hole 19) and extends from the flow path side opening 24 to the back side is employed. As a bearing hole of the shaft bearing portion 7 of the housing 1, a valve It opens at the flow passage wall surface of the first flow passage (flow passage hole 17) located upstream of the seat 11 in the exhaust flow direction (for example, the exhaust passage side in the exhaust pipe of the internal combustion engine (engine)). A bearing hole extending from the road-side opening to the back side may be employed.
In this case, the first protruding shaft portion 21 of the valve shaft (valve shaft 3) of the EGR valve protrudes from the opening of the bearing hole to the first flow path (flow path hole 17), and the first flow path (flow path hole 17). ) Through the valve hole (channel hole 18) and project into the second channel (channel hole 19).

In this embodiment, a frustoconical valve seal surface that can be seated on the seat edge (valve seat) of the valve seat 11 is provided on the outer periphery of the poppet valve body (valve body 2). An annular valve seal surface that can be seated on the opening periphery (valve seat) of the valve seat 11 may be provided.
For example, a multi-cylinder gasoline engine may be used instead of a multi-cylinder diesel engine as an internal combustion engine (engine) mounted on a vehicle such as an automobile. Moreover, you may apply to a single cylinder engine.

1 Housing 2 Valve body (poppet valve body)
3 Valve shaft (valve shaft)
7 Shaft bearing 11 Valve seat 12 Bearing hole 13 Metal bearing (bearing member)
14 Seal member 15 Baffle 16 Filter

Claims (6)

In an exhaust control valve that controls the flow of exhaust discharged from a cylinder of an internal combustion engine,
(A) An opening is formed at the flow path (17-19) through which the exhaust flows, the annular sheet (11) provided around the flow path (17-19), and the wall surface of the flow path (17-19), And a housing (1, 6, 7) having a bearing hole (12) extending from the flow path side opening (24) to the back side;
(B) A valve body (2) that opens and closes the flow path (17 to 19) by contacting and separating from the seat (11), and the valve body (2) are provided so as to be movable together with the bearing hole (12 ) Having a valve shaft (3) accommodated in a reciprocating manner in the valve body (2) and a valve reciprocating in the axial direction of the valve shaft (3);
(C) a cylindrical bearing member (4) that is installed on the back side of the bearing hole (12) and supports the valve shaft (3) so as to be slidable in the axial direction;
(D) A hollow cylindrical pipe (81) which is installed closer to the flow path of the bearing hole (12) than the bearing member (4) and covers the periphery of the valve shaft (3) with a filling space (80) therebetween. )When,
(E) Collecting or trapping foreign matter that is disposed in the filling space (80) so as to block between the outer surface of the valve shaft (3) and the inner surface of the pipe (81). And a filter (16)
The filter (16) employs a wire mesh made of a material having a larger linear expansion coefficient than the valve shaft (3) and the pipe (81) ,
The valve shaft (3) is made of a first metal having substantially the same linear expansion coefficient as the pipe (81).
Is formed,
The filter (16) is more excellent in low temperature shrinkage and high temperature expansion than the first metal.
An exhaust control valve formed of two metals . The exhaust control valve according to claim 1,
The exhaust control valve according to claim 1, wherein the pipe (81) is provided on a cup-shaped baffle (15) that suppresses intrusion of foreign matter contained in the exhaust into the bearing hole (12). The exhaust control valve according to claim 2,
The baffle (15) has a cover (82) that is connected to the flow path side end of the pipe (81) and covers the flow path side opening (24) of the bearing hole (12). Exhaust control valve. The exhaust control valve according to claim 3,
The baffle (15) has an insertion hole (83) that passes through the cover (82) so as to communicate with the inside and outside of the cover (82) and that allows the valve shaft (3) to be inserted in the axial direction thereof. Exhaust control valve to do. The exhaust control valve according to any one of claims 1 to 4,
The filter (16) has an annular portion that contacts the outer surface of the valve stem (3);
When the temperature environment of the filter (16) is a high temperature environment, the annular portion of the filter (16)
Has a scraping function for scraping off deposits adhering to the outer surface of the valve shaft (3).
Exhaust control valve, characterized by that. The exhaust control valve according to any one of claims 1 to 5,
The valve shaft (3) and the pipe (81) are more linearly expanded than the filter (16).
An exhaust control valve characterized by comprising a small material .

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