JP2016133076A - Valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain an EGR valve in a valve-closed state even if excessive load torque is applied to a shaft due to a collision or the like of a valve body with a seating seat via foreign matters, and a malfunction occurs in a valve device.SOLUTION: In an EGR valve, when excessive load torque is sequentially applied to a shaft 2, components are connected and released in a connection/release part α which is arranged at shaft drive means 6. Concretely, the pressure insertion of an output shaft 21 and a lever 31 is released by the excessive load torque which is generated between an electric actuator 9 and the shaft 2. As a result, a link mechanism 10 is brought into a free state with respect to the electric actuator 9 in a state that a valve mechanism part 5 is normally maintained. By this constitution, the EGR valve is maintained in a closed state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a valve device in which a shaft and a valve are combined, and more particularly to a fail-safe technique when an excessive load torque is applied directly or indirectly to a shaft.

(Conventional technology)
A valve device in which a shaft and a valve are joined by a joining technique such as welding is known (see, for example, Patent Document 1).
The prior art will be described using Patent Document 1 as an example.
The valve device of Patent Document 1 is an EGR valve that opens and closes an EGR flow path, and includes a valve mechanism portion having a return spring that returns a valve that opens and closes the EGR flow path to a closed position (an example of an initial position), and a valve And shaft driving means for driving a welded shaft (an example of a joining technique).

  The shaft driving means of Patent Document 1 includes an electric actuator that combines an electric motor and a speed reduction mechanism, and a link mechanism (rotating linear conversion means) that converts the rotational motion output by the electric actuator into linear motion. Then, when the shaft is slid in the axial direction by the operation of the electric actuator, the valve is driven and the EGR gas amount returned to the intake passage is adjusted.

(Problems of conventional technology)
In the EGR valve, when the valve in the open state is fully closed, the electric motor is energized in the valve closing direction for the purpose of shortening the time until the valve is fully closed (that is, for the purpose of improving responsiveness). At this time, deceleration control is performed immediately before the valve is closed to prevent the valve from colliding with the seating seat, and “crash noise, wear due to collision, damage due to collision, etc.” is prevented.

  However, when a foreign object is caught between the valve and the seating seat, the valve and the seating sheet collide with each other through the foreign object before starting deceleration. As a result, an excessive load torque due to the collision is applied to the shaft, and there is a concern that a crack may occur in the welding of the shaft and the valve.

  If cracks occur in the welding between the shaft and the valve, the valve may drop from the shaft. If it is assumed that the valve falls from the shaft, not only will EGR gas be uncontrollable, but the valve that opens and closes the EGR channel will be lost, and the EGR channel will always be open.

  In particular, in the case of a gasoline engine that controls the amount of intake air drawn into the engine by a throttle valve, if the valve is lost and the EGR flow path is normally open, engine stall occurs and the engine can be restarted. It will disappear.

In the above, “prior art and its problems” have been described by taking the EGR valve as an example.
However, the possibility of losing the coupling between the shaft and the valve due to excessive load torque being applied to the shaft is not unique to the EGR valve, but various valves having a structure in which the shaft and the valve are coupled. There are concerns that arise in the device.

In the above description, “welding” is used as a specific example of the joining technique.
However, the possibility of losing the coupling between the shaft and the valve due to excessive load torque being applied to the shaft is not unique to welding, such as “press fitting, screw fastening, adhesion, caulking, fitting”, etc. There are also concerns that arise in various coupling technologies.

In the above description, the valve device in which the shaft is slid in the linear direction has been described as an example.
However, the possibility of losing the coupling between the shaft and the valve due to excessive load torque being applied to the shaft is not unique to the valve device in which the shaft is driven to slide in a linear direction. There are also concerns that arise in butterfly valves, hinge valves, and the like.

In the above description, the normally closed type valve device in which the valve is returned to the fully closed position by the action of the return spring has been described as an example.
However, the possibility of losing the coupling between the shaft and the valve due to excessive load torque being applied to the shaft is not unique to the normally closed type valve device, and the valve is fully opened by the action of the return spring. It is a normally open type that returns to the position, or a valve device that returns the valve to a different opening (intermediate opening, opening of the valve dead zone, etc.) from the fully closed position and the fully open position by the action of the return spring. There are concerns that arise.

JP 2014-043852 A

  The present invention has been made in view of the above-described problems, and the object of the present invention is to provide an initial valve even when a malfunction occurs in the valve device due to excessive load torque being applied to the shaft. To provide a valve device that can be kept in position.

When an excessive load torque is applied to the shaft, the connection between the components existing in the load torque transmission path is released upon receiving the excessive load torque. In this manner, the shaft driving means is intentionally provided with a coupling release portion for releasing the coupling.
For this reason, even if a malfunction occurs in the valve device due to excessive load torque being applied to the shaft, the coupling of parts is released in the shaft driving means to keep the valve mechanism part normal. Therefore, the valve can be kept at the initial position by the action of the return spring.

(A) Cross section of EGR valve along axial direction of output shaft, (b) Cross section of EGR valve along vertical direction with respect to axial direction of output shaft. It is an external view of an EGR valve showing the inside of the electric actuator with the sensor cover removed. It is a claim corresponding figure of an EGR valve.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the invention will be described in detail with reference to the drawings.

  [Example] disclosed below is a specific example of the present invention, and it goes without saying that the present invention is not limited to the example.

[Example 1]
Embodiment 1 will be described with reference to FIGS. In the following description, the upper side of FIG. 1 will be referred to as the upper side, and the lower side of FIG. 1 will be referred to as the lower side. However, this vertical direction is a direction for explaining the embodiment and does not relate to the mounting direction of the vehicle. .
In this embodiment, the present invention is applied to an EGR valve that opens and closes an EGR flow path 1 that returns a part of exhaust gas discharged from the engine as EGR gas to the intake side of the engine.

An exhaust gas recirculation device (EGR device) is mounted on an engine for vehicle travel.
The exhaust gas recirculation device is a well-known technique in which part of exhaust gas discharged from the engine is returned to the intake side of the engine as EGR gas, thereby mixing EGR gas, which is non-combustible gas, into part of the intake air.
The exhaust gas recirculation device includes an EGR valve that opens and closes the EGR flow path 1 for returning a part of the exhaust gas flowing through the exhaust passage to the intake passage and adjusts the opening thereof.

  The EGR valve may be a high-pressure EGR valve that returns EGR gas to a high negative pressure generation range in the intake passage (intake downstream of the throttle valve), or a low negative pressure generation range in the intake passage (intake upstream of the throttle valve). Side: For example, a low-pressure EGR valve that returns EGR gas to the intake upstream side of the compressor in the case of a turbocharged vehicle may be used.

The EGR valve is a specific example of the valve device, and includes a valve 3 that is driven to open and close via a shaft 2 that is supported slidably in the axial direction, and a return spring 4 that returns the valve 3 to an initial position. It has a valve mechanism section 5 and a shaft driving means 6 for driving the shaft 2, and the shaft 2 and the valve 3 are coupled by welding (an example of a coupling technique).
Of course, the valve mechanism 5 used for the EGR valve is a normally closed type in which the valve 3 is closed by the urging force of the return spring 4.

  The shaft driving means 6 includes an electric actuator 9 in which an electric motor 7 (rotational torque generating means for converting electric power into rotational torque) and a speed reduction mechanism 8 (torque amplifying means for amplifying rotational torque output from the electric motor 7) are combined. And a link mechanism 10 that is interposed between the electric actuator 9 and the shaft 2 and transmits the output of the electric actuator 9 to the shaft 2.

Hereinafter, the EGR valve will be described more specifically.
The EGR valve includes a housing 11 in which a part of the EGR flow path 1 is formed, and the valve mechanism 5 and the shaft driving means 6 described above are provided in the housing 11.

A specific structure of the valve mechanism 5 will be described.
The valve mechanism 5
A shaft 2 slidably supported in the vertical direction (axial direction) with respect to the housing 11;
A valve 3 connected to the shaft 2 by welding;
A return spring 4 that biases the shaft 2 in the valve closing direction (upward);
It is configured with.

The housing 11 is made of, for example, aluminum, and a ring plate-shaped seating sheet 12 provided by a member (such as stainless steel) having excellent heat resistance, corrosion resistance, and wear resistance is fixed at a position where the valve 3 is seated. Has been placed.
A sensor cover 13 that covers the electric actuator 9 and a link cover 14 that covers the link mechanism 10 are assembled to the housing 11 by screwing or caulking technology.
In addition, the code | symbol 15 provided in the housing 11 is a flange for vehicle fixation.

The shaft 2 is a movable member made of metal (such as stainless steel) that is slidably supported only in the vertical direction (axial direction), and has a substantially cylindrical bar shape.
Specifically, the shaft 2 is inserted inside a bearing (metal bearing or the like) 16 fixed by press-fitting or the like inside a bearing receiving hole formed in the housing 11, and slides in the axial direction with respect to the housing 11. It is supported freely. Then, when the shaft 2 moves in the axial direction, the valve 3 moves in the axial direction.
A pipe 17 and an oil seal 18 are disposed between the housing 11 and the shaft 2 and connected to the EGR flow path 1 to prevent deposits and EGR gas from entering upward (on the bearing 16 side). .

The valve 3 is a metal (stainless steel, etc.) umbrella valve that is joined to the lower end of the shaft 2 by welding. The valve 3 moves in the axial direction integrally with the shaft 2 to open and close the EGR flow path 1. The opening area is variable. And the valve 3 adjusts the amount of EGR gas returned to the intake passage by changing the opening area of the EGR flow path 1.
Specifically, the valve 3 is closed when seated on the seating seat 12, and the valve 3 is opened when the valve 3 is separated below the seating seat 12. The degree of communication (opening area) between the upstream side and the downstream side of the valve 3 increases as the amount by which the valve 3 separates downward from the seating seat 12 (valve lowering amount) increases.

The return spring 4 is a compression coil spring disposed around the shaft 2, and applies a restoring force to the shaft 2 via the spring seat 19.
Specifically, the return spring 4 is sandwiched between the housing 11 and the spring seat 19 in a compressed state.

The spring seat 19 abuts on a yoke 34 (a component of the link mechanism 10 that is coupled to the shaft 2), which will be described later, and a restoring force (an upward spring force) of the return spring 4 is applied to the shaft 2 via the yoke 34. To tell.
Unlike this embodiment, the spring seat 19 is directly fixed to the shaft 2 or the spring seat 19 is brought into contact with the step provided on the shaft 2 (step between the lower small diameter portion and the upper large diameter portion). The restoring force of the return spring 4 (upward spring force) may be transmitted to the shaft 2.

A specific configuration of the electric actuator 9 will be described.
The electric actuator 9 rotationally drives an output shaft 21 that is an output shaft thereof.
An electric motor 7 that generates rotational torque when energized;
A speed reduction mechanism 8 that amplifies the rotational torque of the electric motor 7 and transmits the amplified torque to the output shaft 21;
A rotation angle sensor 22 for detecting the rotation angle of the output shaft 21;
It is configured with.

  The electric motor 7 is a well-known DC motor that changes the rotation direction when the energization direction is switched and generates a rotational torque according to the energization amount. After being inserted into the motor housing chamber formed in the housing 11, the electric motor 7 is screwed. It is fixed to the housing 11 by 23 or the like.

The speed reduction mechanism 8 is accommodated in a space formed between the housing 11 and the sensor cover 13.
The speed reduction mechanism 8 of this embodiment is a gear speed reducer in which a plurality of gears are combined,
A pinion gear (motor gear) 24 that rotates integrally with the electric motor 7;
An intermediate gear 25 that is rotationally driven by the pinion gear 24;
An output gear (final gear) 26 that is rotationally driven by the intermediate gear 25;
The output gear 26 rotates integrally with the output shaft 21.

The pinion gear 24 is a small-diameter external gear coupled to the output shaft of the electric motor 7.
The intermediate gear 25 is a double gear in which a large-diameter gear 25 a and a small-diameter gear 25 b are provided concentrically. A support shaft provided at the center of the intermediate gear 25 is rotatable by the housing 11 and the sensor cover 13. Supported. The large diameter gear 25 a in the intermediate gear 25 is always meshed with the pinion gear 24, and the small diameter gear 25 b in the intermediate gear 25 is always meshed with the output gear 26.

The output gear 26 is a large-diameter external gear that is formed by inserting a fastening plate 26a that is coupled to the end portion of the output shaft 21 by caulking or the like. The external gear is an intermediate gear 25 (specifically, a small-diameter gear 25b). It is provided only in the meshing range.
The output gear 26 transmits the rotational torque amplified by the reduction in the order of the pinion gear 24 → the large diameter gear 25 a → the small diameter gear 25 b → the output gear 26 to the output shaft 21.

  The output shaft 21 driven by the output gear 26 is a cylindrical rod-shaped metal (iron, stainless steel, etc.) shaft body rotatably supported by bearings (for example, a plurality of ball bearings) 28 supported by the housing 11. A small-diameter shaft portion that is inserted into a lever 31 (to be described later) and is coupled to the lever 31 is provided at the distal end portion. Further, the shaft core of the output shaft 21 is provided at a right angle (horizontal direction) with respect to the shaft core (vertical direction) of the shaft 2.

A specific configuration of the link mechanism 10 will be described.
The link mechanism 10 of this embodiment is a rotational linear conversion means that converts the rotational motion of the electric actuator 9 into the linear motion of the shaft 2.
A lever 31 that rotates integrally with the output shaft 21;
An arcuate shaft 32 that rotates integrally with the lever 31 and moves in the arc direction around the output shaft 21;
A follower 33 that is rotatably mounted around the arcuate shaft 32;
A yoke 34 that engages with the follower 33 only in the vertical direction;
It is configured with.

  The lever 31 is a metal (iron, stainless steel, etc.) member that transmits the rotational torque of the output shaft 21 to the arcuate shaft 32 and drives the arcuate shaft 32 in the arc direction. The output shaft 21 and the lever 31 are They are joined by press-fitting (an example of a joining technique).

  As described above, the arcuate shaft 32 is a cylindrical rod-shaped metal (iron, stainless steel, etc.) shaft member that moves in the arc direction by the rotation of the lever 31, and the axis of the arcuate shaft 32 is the output shaft. 21 is provided parallel to the axis of the shaft 21 and perpendicular to the axis of the shaft 2. The arcuate shaft 32 may be provided integrally with the lever 31, but in this embodiment, the lever 31 and the arcuate shaft 32 are coupled by press fitting.

  The follower 33 is an annular rolling element (such as a bearing) that is fitted around the arcuate shaft 32 and is rotatable with respect to the arcuate shaft 32. The follower 33 has an outer peripheral surface provided on the yoke 34. It fits inside the recess 34a.

The yoke 34 is a metal (aluminum, iron, stainless steel, etc.) member that is joined to the upper end of the shaft 2 by press fitting, and moves only in the vertical direction together with the shaft 2.
The yoke 34 converts the movement of the follower 33 in the arc direction (same as the movement of the arc-moving shaft 32 in the arc direction) into the movement of the shaft 2 in the axial direction. A recess 34a having a substantially U-shaped cross section is provided.

  The concave portion 34 a has parallel surfaces that sandwich the follower 33 in the vertical direction, and the yoke 34 moves in the vertical direction together with the follower 33 when the follower 33 moves in the vertical direction. Further, the recess 34a is provided so as not to come into contact with the follower 33 even when the follower 33 moves in the horizontal direction, and is provided so as to release a moving component in the left-right direction of the follower 33. That is, it is provided so that only the vertical movement component of the movement of the follower 33 in the arc direction is transmitted to the yoke 34 by the contact portion of the recess 34 a and the follower 33.

The rotation angle sensor 22 is a position sensor that detects the opening degree of the valve 3 by detecting the rotation angle of the output shaft 21, and an output signal corresponding to the rotation angle of the output shaft 21 (corresponding to the opening degree of the valve 3). (In this embodiment, the sensor voltage) is output to an ECU (abbreviation of engine control unit).
Specifically, the rotation angle sensor 22 is a magnetic sensor that detects relative rotation of two members in a non-contact manner, and has a substantially cylindrical shape that is inserted into the output gear 26 and rotates integrally with the output shaft 21. The magnetic circuit unit and a magnetic detection unit that is attached to the sensor cover 13 and arranged in a non-contact manner with respect to the magnetic circuit unit. The output signal generated by the magnetic detection unit (specifically, the Hall IC is The sensor voltage to be output) is given to the ECU.

  The ECU is a well-known electronic control device equipped with a microcomputer, and the rotation angle of the output shaft 21 (that is, the actual opening of the valve 3) detected by the rotation angle sensor 22 is the engine operating state (engine speed). EGR control means (control program) is provided for controlling the electric motor 7 so that the target rotation angle (that is, the target opening degree of the valve 3) calculated in accordance with the accelerator opening degree or the like.

  The EGR control means of the ECU controls energization of the electric motor 7 in the valve closing direction for the purpose of shortening the time until the valve is fully closed when the valve 3 in the valve open state is fully closed. At this time, the EGR control means of the ECU performs the deceleration control of the shaft 2 immediately before closing the valve so that the valve 3 does not collide with the seating seat 12. However, when a foreign object is caught between the valve 3 and the seating seat 12, the valve 3 and the seating sheet 12 collide with each other through the foreign object before starting deceleration, and an excessive load torque is applied to the shaft 2. There are concerns.

Therefore, the EGR valve of this embodiment is provided with a coupling release portion α that intentionally releases the coupling between the components existing in the load torque transmission path when an excessive load torque is applied to the shaft 2. ing.
The coupling release portion α is intentionally provided at a coupling location of components that are driven and connected to the shaft 2 among components constituting the shaft driving means 6.

Specifically, the uncoupling unit α is
A coupling portion between the electric motor 7 and the speed reduction mechanism 8 (in this embodiment, a coupling portion between the output shaft of the electric motor 7 and the pinion gear 24),
A coupling part (for example, a coupling part between the output gear 26 and the output shaft 21) of the parts constituting the speed reduction mechanism 8;
A connecting portion between the speed reduction mechanism 8 and the link mechanism 10 (in this embodiment, a connecting portion between the output shaft 21 and the lever 31),
A connecting portion between parts constituting the link mechanism 10 (for example, a connecting portion between the lever 31 and the arcuate shaft 32),
It is provided in either.

More specifically, in this embodiment, a coupling release portion α is provided at the coupling portion between the output shaft 21 and the lever 31.
This will be described in more detail.
In the prior art, the bonding strength of each part of the EGR valve has been sufficiently increased. In other words, the bonding portion of any component is provided with high bonding strength. As a result, in the prior art, as shown in the upper part of [Table 1] below, “the press-fit strength of the output shaft 21 and the lever 31”, “the press-fit strength of the yoke 34 and the shaft 2”, “the valve 3 and the shaft 2. "Welding strength" was provided at substantially the same strength.

  On the other hand, in this embodiment, as shown in the lower part of [Table 1] below, “the press-fit strength of the yoke 34 and the shaft 2” and “the weld strength of the valve 3 and the shaft 2” are substantially the same as in the prior art. However, “the press-fit strength of the output shaft 21 and the lever 31” is set lower than “the press-fit strength of the yoke 34 and the shaft 2” and “the weld strength of the valve 3 and the shaft 2”.

(Effect of Example 1)
When the ECU 3 fully closes the valve 3 in the valve open state, the electric motor 7 is energized and controlled in the valve closing direction. However, the deceleration control of the shaft 2 is performed immediately before the valve is closed (just before the valve 3 is seated on the seat 12). To prevent the valve 3 from colliding with the seating seat 12.
However, if a foreign object is caught between the valve 3 and the seating sheet 12 and the valve 3 and the seating sheet 12 collide with each other through the foreign object before starting deceleration, an excessive load torque is generated in the shaft 2 due to the collision.

  In the EGR valve of this embodiment, as described above, when an excessive load torque is applied to the shaft 2, the parts are released from the connection at the connection release portion α provided in the shaft driving means 6. Specifically, the coupling between the electric actuator 9 and the link mechanism 10 is released. That is, the press-fitting of the output shaft 21 and the lever 31 is released by an excessive load torque generated between the electric actuator 9 and the shaft 2. As a result, the link mechanism 10 is in a free state with respect to the electric actuator 9 in a state where the valve mechanism portion 5 is normally maintained, and the valve 3 is maintained in the fully closed position by the action of the return spring 4.

  As described above, since the present invention is applied to the EGR valve, even when an excessive load torque is applied to the shaft 2, the coupling is released at the coupling releasing portion α provided in the shaft driving means 6. There is no fear that the valve 3 falls from 2, and the EGR valve is kept closed by the action of the return spring 4.

For this reason, even if the engine in which this embodiment is used is a gasoline engine and the EGR valve malfunctions due to excessive load torque being applied to the shaft 2, the EGR valve is kept closed. There is no problem that the engine stalls and the engine cannot be restarted.
Of course, the present invention is not limited to a gasoline engine, and an effect of keeping the EGR valve closed can be obtained even in a diesel engine or the like.

  In the above embodiment, the shaft 2 and the valve 3 are connected by welding. However, the connecting portion of the shaft 2 and the valve 3 is not limited to welding, but “press fitting, screw fastening, adhesion, caulking, fitting” It is possible to apply various methods such as “combination”.

  In the above-described embodiment, an example in which the coupling release portion α (the coupling portion between the output shaft 21 and the lever 31 in the embodiment) is provided by press-fitting is shown. However, the coupling portion that is released by excessive load torque is limited to press-fitting. Instead, various applications such as “welding with reduced strength, screw fastening, adhesion, caulking, and fitting” can be applied.

  In the above embodiment, the coupling release portion α is provided in the coupling portion between the electric actuator 9 and the link mechanism 10 (that is, the coupling portion between the output shaft 21 and the lever 31). You may provide in the coupling | bond part of the electric motor 7 and the speed reduction mechanism 8, "the coupling part of the parts which comprise the speed reduction mechanism 8," and "the coupling part of the parts which comprise the link mechanism 10."

  In the above-described embodiment, an example in which the present invention is applied to a valve device in which the shaft 2 is slidably driven in a linear direction has been described. It may be applied.

In the above embodiment, the link mechanism 10 that converts the movement of the arcuate shaft 32 and the follower 33 in the arc direction into the linear direction using the yoke 34 is shown as an example of the rotating linear conversion means that changes the rotary motion into the linear motion. However, the structure of the link mechanism 10 is not limited, and other rotating linear conversion means such as a cam link using a cam groove or a rack and pinion may be used.
Alternatively, as described above, when a butterfly valve or a hinge valve in which the shaft 2 is rotationally driven is adopted, the link mechanism 10 may be eliminated and the shaft 2 may be directly rotated by the electric actuator 9.

In the above-described embodiment, an example in which a row type (sequentially meshing type) gear reducer is used as an example of the speed reduction mechanism 8 is shown. You may do it.
Alternatively, the speed reduction mechanism 8 may be eliminated. That is, the output of the high torque electric motor 7 may be directly applied to the link mechanism 10. Alternatively, when the link mechanism 10 is abolished, the output of the high torque electric motor 7 may be directly applied to the shaft 2.

  In the above embodiment, an example in which the present invention is applied to a normally closed type valve device has been described. However, the valve 3 is opened differently from the fully closed position and the fully opened position by the action of the normally open type or the return spring 4. The present invention may be applied to a valve device of a type that is returned to a degree (intermediate opening degree, opening degree of valve closing dead zone, etc.).

  In the above embodiment, an example in which the present invention is applied to an EGR valve has been shown. However, if the valve device has a structure in which the shaft 2 and the valve 3 are combined, the present invention is applied to a valve device for other uses. May be.

2 Shaft 3 Valve 4 Return spring 5 Valve mechanism 6 Shaft drive means α Decoupling part

Claims (5)

A valve mechanism (5) having a valve (3) driven to open and close via a slidably supported shaft (2) and having a return spring (4) for returning the valve (3) to an initial position; Shaft drive means (6) for driving the shaft (2),
In the valve device in which the shaft (2) and the valve (3) are combined and provided,
In this valve device, when an excessive load torque is applied to the shaft (2), a coupling release section (for releasing the coupling between the component (21) and the component (31) existing in the transmission path through which the load torque is transmitted) α), and this coupling release part (α) is provided in the shaft driving means (6). The valve device according to claim 1,
The shaft drive means (6) has an electric motor (7) that converts electric power into rotational torque, and an electric actuator (9) that has a speed reduction mechanism (8) that amplifies the rotational torque of the electric motor (7). A link mechanism (10) for transmitting the output of the electric actuator (9) to the shaft (2),
The uncoupling part (α)
A connecting portion between the electric motor (7) and the speed reduction mechanism (8);
A connecting portion between the parts constituting the speed reduction mechanism (8);
A joint between the speed reduction mechanism (8) and the link mechanism (10);
A connecting portion between the parts constituting the link mechanism (10);
It is provided in either of these. The valve apparatus characterized by the above-mentioned. The valve device according to claim 2,
The valve mechanism according to claim 1, wherein the link mechanism (10) is rotating linear conversion means for converting the rotational movement of the electric actuator (9) into the linear movement of the shaft (2). In the valve apparatus as described in any one of Claims 1-3,
The valve mechanism (5) is a normally closed type that closes the valve (3) by the urging force of the return spring (4). The valve device according to claim 4,
This valve device is an EGR valve that opens and closes an EGR flow path (1) for returning a part of exhaust gas discharged from the engine to the intake side of the engine as EGR gas.

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