JP5454358B2 - Valve drive device - Google Patents

Description

  The present invention relates to a valve driving device that drives a valve by decelerating the rotation of a rotating shaft of a motor with a speed reducing mechanism and converting the rotational motion of the speed reducing mechanism into a reciprocating linear motion. The present invention relates to a valve driving device suitable for use in an actuator for EGR valve control.

[Conventional technology]
2. Description of the Related Art Conventionally, as a valve driving device for driving a valve, as shown in FIGS. 12 and 13, an electric actuator including an electric motor 101 and a rod 102 that reciprocates in an axial direction is known (for example, Patent Document 1). reference).
The electric actuator includes a reduction mechanism that reduces the rotation of the electric motor 101 in two steps, a reciprocating slider link mechanism that converts the rotational movement of the reduction mechanism into a linear movement of the rod 102, and a thrust that supports the rod 102 in the reciprocating movement direction. And a bearing 103. The thrust bearing 103 has a through-hole penetrating in the axial direction of the rod 102 and is held and fixed in the bearing hole of the actuator case.
The reduction mechanism includes a pinion gear 104 fixed to the output shaft of the electric motor 101, an intermediate gear 105 that rotates in mesh with the pinion gear 104, a final gear 106 that rotates in mesh with the intermediate gear 105, and the like. The intermediate gear 105 is rotatably attached to the outer periphery of the support shaft 111. The final gear 106 is rotatably attached to the outer periphery of the support shaft 112.

A toggle lever 107 is connected to the rod 102 of the electric actuator via a first pivot 113. Further, a toggle lever 107 is connected to the final gear 106 via a second pivot 114. The first pivot 113 is driven into the first fitting hole of the toggle lever 107 and fixed to the toggle lever 107, and the second pivot 114 is driven into the second fitting hole of the toggle lever 107 and moved to the toggle lever 107. It is fixed to.
In the electric actuator described in Patent Document 1, the electric motor 101 rotates the three gears 104 to 106 of the speed reduction mechanism, and the toggle lever 107 connected to the final gear 106 via the second pivot 114 moves the rod 102 in the axial direction. The rotary motion of the final gear 106 is converted into a reciprocating linear motion of the rod 102 by pressing (or pulling back).
Here, 108 is a disc-shaped valve that is controlled to open and close by an electric actuator. A link lever 119 is installed between the rod 102 and the valve 108.

[Conventional technical problems]
By the way, in recent years, with the tightening of exhaust gas regulations for engines mounted on automobiles, it has become obligatory to install exhaust gas related OBD (fault diagnosis function by in-vehicle diagnostic device).
Therefore, when the electric actuator described in Patent Document 1 is used as a valve driving device for EGR valve opening / closing control or waste gate valve opening / closing control, it is necessary to directly detect the stroke position of the rod 102 as an OBD requirement. . However, the electric actuator described in Patent Document 1 cannot directly detect the stroke position of the rod 102.

In addition, in the electric actuator described in Patent Document 1, a sensing lever (sensing unit) 109 is described for directly detecting the stroke position of the rod 102, but the relationship between the sensing lever 109 and the stroke sensor (sensor body). Is not clearly described.
Further, in the electric actuator described in Patent Document 1, when the link lever 119 moves, the rod 102 swings around the axis line due to the illustrated structure. In order to absorb the vibration of the rod 102, play is provided, but the operation of the link lever 119 does not follow the movement of the rod 102. As a result, the movement of the valve 108 to be controlled by the electric actuator and the movement of the rod 102 do not coincide with each other, and the controllability of the stroke amount of the rod 102 is deteriorated.
Further, when the link lever 119 is not provided with backlash, in the structure shown in the figure, since the vibration of the rod 102 cannot be absorbed, a force is applied to the thrust bearing 103 of the rod 102, and the rod 102 squeezes the inner periphery of the thrust bearing 103. 102 may become inoperable.

International Publication No. 2009/062928 Pamphlet

  An object of the present invention is to provide a valve drive device that can directly detect a stroke position of a rod that is a final operation stage. Another object of the present invention is to provide a valve drive device that can improve the controllability of the stroke amount of the rod. Furthermore, it is providing the valve drive device which can detect the failure of a rod.

The invention according to claim 1 is a valve driving device that performs opening / closing control of the valve in accordance with the amount of movement of the rod in the stroke axis direction (reciprocating direction) (the amount of stroke of the rod). And a rod stroke detecting means having a sensor for detecting the stroke position of the sensing unit.
According to the first aspect of the present invention, since the sensing unit is integrally installed on the rod for controlling the opening and closing of the valve, the stroke position of the rod, which is the final operation stage of the valve driving device, can be directly detected. . As a result, since the detection accuracy of the stroke position of the rod is improved, the controllability of the stroke amount of the rod, that is, the controllability of the valve opening degree control can be improved. Further, when the stroke position of the sensing unit detected by the sensor does not reach or approach the set target position even after a predetermined time has elapsed, it can be determined that the rod or the valve drive device is out of order. That is, failure diagnosis of the valve, rod or valve drive device can be performed. Thereby, the OBD requirement can be satisfied.

Further , according to the present invention , the cam groove having a shape corresponding to the operation pattern of the valve, the cam rotating with the rotation of the speed reduction mechanism, and the follower movably inserted in the cam groove of the cam are provided. It constitutes a conversion mechanism.
Further , according to the present invention , the sensing unit is integrated with the rod having the support shaft that rotatably supports the follower, one end side connected to the cam via the follower and the support shaft, and the other end side connected to the valve. It is installed.

Further, according to the present invention , the force that the follower pushes the cam through the support shaft of the rod becomes a load when the motor is driven, but the load acting direction on the center line in the axial direction of the rod and the contact surface between the cam and the follower Therefore, the load from the rod (valve reaction force) does not work in the direction of rotating the cam.
Therefore, when the valve is fully closed and fully opened, the motor holding current required to hold the valve in a stationary state at the fully closed and fully open positions of the valve is reduced against the load from the rod (valve reaction force). As a result, power consumption can be reduced.
Here, it is assumed that the valve driving device of the present invention is applied to an actuator that is frequently used to drive the valve to the fully closed position and the fully open position (for example, an actuator that controls opening and closing of a waste gate valve or an EGR valve). However, power consumption (current consumption) when the valve is fully closed and fully open can be reduced.

According to the second aspect of the present invention, the force that the follower pushes the cam through the support shaft of the rod becomes a load when the motor is driven, but when the valve is fully closed or fully opened, the load on the center line in the axial direction of the rod Since the action direction and the common tangential direction on the contact surface of the cam and follower are perpendicular to each other, the load from the rod (valve reaction force) does not work in the direction of rotating the cam. Become.
Therefore, when the valve is fully closed or fully open, the motor holding current required to hold the valve in a stationary state in the valve fully closed or fully open position against the load from the rod (valve reaction force) is reduced. As a result, power consumption can be reduced.
Further , according to the present invention , the positional relationship (configuration) is such that the rotation center of the cam and the rotation center of the follower are on the center line in the axial direction of the rod. Thereby, when the valve is fully closed or fully opened, the motor holding current required to hold the valve in the fully closed position or the fully open position of the valve can be effectively reduced, so that the power consumption can be further reduced.
Furthermore, according to the present invention, when the valve fully closed side in the load acting direction of the rod is used as a reference, the positional relationship (configuration) is set in the order of the follower, the rotation center of the cam, and the rod. Thereby, when the valve is fully closed or fully opened, the motor holding current required to hold the valve in the fully closed position or the fully open position of the valve can be effectively reduced, so that the power consumption can be further reduced.

According to the third aspect of the present invention, the first gear that is rotationally driven by the motor and the first gear that decelerates the rotation of the motor (output shaft thereof) (so as to have a predetermined reduction ratio) and the first gear. The second gear rotates while meshing with the gear.
As the speed reduction mechanism, for example, a two-stage reduction gear mechanism having a pinion gear fixed to the output shaft of the motor, an intermediate gear that rotates while meshing with the pinion gear, a final gear that meshes with the intermediate gear, and the like may be used. Further, a multistage reduction gear mechanism having a worm gear (other helical gear, spur gear, output gear) or the like may be used as the reduction mechanism.

According to the fourth aspect of the present invention, the straight line connecting the rotation center of the cam and the rotation center of the follower is substantially coincident with the straight line connecting the rotation center of the cam and the rotation center of the first gear (substantially on the same straight line). It is a positional relationship (configuration).
Here, when the rotation shaft of the second gear and the rotation shaft of the cam are made common (configured with the same parts), the rotation angle of the cam and the operation angle of the second gear are equal.
At this time, the straight line connecting the rotation center of the cam and the rotation center of the follower, the rotation center of the cam (= rotation center of the second gear) and the rotation center of the first gear (= engagement of the first gear and the second gear). With the positional relationship in which the straight line connecting (position) substantially matches, the operation locus of the second gear can be substantially matched (inserted) in the operation locus (projection surface) of the cam. Accordingly, the physique of the valve drive device can be reduced in size compared with a device in which the cam operation locus and the second gear operation locus are significantly different, and therefore, the mountability to a vehicle or the like can be improved.

According to the fifth aspect of the present invention, the rod stroke detecting means has the stroke detection direction of the sensing unit in a direction parallel to the stroke axis direction (reciprocating direction) of the rod. That is, the sensing unit is integrally installed on the rod in parallel with the stroke detection direction of the sensing unit and the stroke axis direction (reciprocating direction) of the rod.
Thereby, the effect of the invention of claim 1 can be improved.
The rod axis center line extending straight in the stroke axis direction (reciprocating direction) of the rod center and the center line extending straight in the stroke detection direction of the sensing unit coincide with the center line of the sensing unit. If the stroke detection direction and the rod stroke axis direction (reciprocating direction) are parallel, they may be installed offset from the rod axis center line.

According to the sixth aspect of the present invention, the rod bearing for supporting the rod in the stroke axial direction (reciprocating direction) and the slide shaft extended in the direction parallel to the axial direction of the rod bearing are provided. .
When the motor is driven from the fully closed position to the open position (including the intermediate position and the fully open position), or when the valve is driven from the fully open position to the closed position (including the intermediate position and the fully closed position). Furthermore, by moving the rod in parallel along the two axes of the rod bearing (in the axial direction) and the slide shaft (in the axial direction), the rod bearing and the slide shaft play back and forth in the stroke axis direction (reciprocating direction) of the rod. And swing in the rotational direction can be regulated. Therefore, since the movement of the sensing unit installed integrally with the rod is restricted, the sensing unit can be moved in a “linear” manner. As a result, the detection accuracy of the stroke position of the rod can be improved.

According to the seventh aspect of the present invention, the valve is a poppet valve installed on the tip side of the rod in the stroke axis direction (reciprocating direction).
In this case, the valve drive device can be used as an actuator that controls opening and closing of an exhaust gas control valve such as an EGR valve.

According to the eighth aspect of the present invention, the link mechanism for converting the linear motion of the rod into the rotational motion of the valve is installed between the rod and the valve of the valve driving device.
This link mechanism has a lever or the like for connecting the rod and the valve.
The rod has a first hinge pin that rotatably supports the lever. For example, the first hinge pin is formed integrally with the rod or fixed to the rod.
The valve has a second hinge pin that rotatably supports the lever. For example, the second hinge pin is formed integrally with the valve or fixed to the valve.
The valve driven by the rod of the valve driving device is a hinge valve connected to the tip end side in the stroke axial direction (reciprocating direction) of the rod via the first hinge pin, the lever and the second hinge pin.
In this case, the valve drive device can be used as an actuator for controlling opening and closing of an exhaust gas control valve such as a waste gate valve or an EGR valve, or as an actuator for controlling a variable capacity turbocharger.

According to invention of Claim 9, the rod is comprised by the 1st rod connected with a conversion mechanism, and the 2nd rod connected with a valve | bulb. The valve drive device has a rod bearing that supports the first rod in the stroke axis direction (reciprocating direction), and a rotary joint that connects the first rod and the second rod (spherical body (ball), socket with nut). Guides, spherical bearings, and connecting pins).
By the way, when the second rod strokes in one side of the stroke axis direction (reciprocating direction) (for example, the valve opening side or the valve closing side) to rotate the lever, the second rod swings according to the rotation range of the lever. (For example, the second rod swings in the rotational direction around its central axis).

Here, in the case where the first rod and the second rod are integral parts, when the second rod is shaken, a radial force is applied (acted) to the rod bearing, and the first rod moves the inner circumference of the rod bearing. This may cause the first rod to become inoperable. Therefore, the first rod and the second rod are configured as separate parts, and a rotary joint is installed between the first rod and the second rod, so that the swing of the second rod is absorbed by the rotary joint. .
As a result, it is possible to suppress the occurrence of a problem that the first rod squeezes the inner periphery of the rod bearing and the first rod becomes inoperable.

According to the invention described in claim 10, the center line of the rod in the stroke axis direction (reciprocating direction) and the center line of the lever operating angle (the center of the angle between the center line when the lever is fully closed and the center line when the lever is fully open) (Line) and the vertical relationship (configuration). Thereby, the deflection angle of the rod due to the opening and closing of the valve becomes the smallest.
Here, when the rod stroke amount is set to be small (rod runout <play between the rod and the rod bearing), even if the first rod and the second rod are integral parts, the rod However, it is possible to suppress the trouble that the rod becomes inoperable due to the inner circumference of the rod bearing.
Further, when the rod stroke amount is set to be large, the sliding range of the rotary universal joint can be reduced, so that the reliability of the rotary universal joint can be improved.

According to the eleventh aspect of the present invention, the sensing unit installed integrally with the rod includes a magnetic body. In addition, the component adjacent to the sensing unit is formed (configured) by a nonmagnetic material. The sensor has a non-contact type magnetic detection element that detects a change in the magnetic field generated by the magnet in response to the stroke position of the sensing unit.

(Example 1) which is the explanatory view which showed the valve fully closed state of the electric actuator. (Example 1) which is sectional drawing which showed the valve | bulb fully closed state of the electric actuator. It is explanatory drawing which showed the valve full open state of the electric actuator (Example 1). (Example 1) which is sectional drawing which showed the valve | bulb fully open state of the electric actuator. It is explanatory drawing which showed the connection positional relationship of a rod and a link lever (Example 1, 3, and 4). (Example 2) which is the explanatory drawing which showed the valve fully closed state of the electric actuator. (Example 3) which is the explanatory drawing which showed the valve fully closed state of the electric actuator. (Example 3) which is sectional drawing which showed the valve | bulb fully closed state of the electric actuator. (Example 3) which is the explanatory drawing which showed the valve full open state of the electric actuator. (Example 3) which is sectional drawing which showed the valve | bulb fully open state of the electric actuator. (Example 4) which is the explanatory drawing which showed the valve fully closed state of the electric actuator. It is the front view which showed the electric actuator (conventional technique). It is the side view which showed the electric actuator (prior art).

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The present invention directly detects the stroke position of the rod which is the final operation stage, improves the controllability of the stroke amount of the rod, and detects the failure of the rod. That was realized. In addition, it was realized by installing the sensing unit integrally on the guide that strokes with the rod.
Specific embodiments will be described in detail with respect to the following four examples. Examples 1 and 2 show examples to which the present invention is applied. Examples 3 and 4 These show reference examples to which the present invention is not applied.

[Configuration of Example 1]
FIGS. 1 to 5 show Embodiment 1 of the present invention, and FIGS. 1 and 2 are views showing the operating state of the electric actuator when the wastegate valve (hinge valve) is fully closed. FIG. 4 is a view showing an operating state of the electric actuator when the waste gate valve is fully opened.

The valve drive device of the present embodiment is used as an electric actuator that opens and closes a waste gate valve (hinge valve) 1.
The waste gate valve 1 is a valve body of an exhaust gas control valve that opens and closes a waste gate flow path of a turbocharger installed in an internal combustion engine (engine). The waste gate valve 1 is a valve operating range from a valve fully closed position (see FIG. 1) to a valve fully open position (see FIG. 3) based on a control signal from an engine control unit (ECU) during engine operation. The opening area (exhaust gas distribution area) of the waste gate flow path is changed by the rotation operation.
An L-shaped shaft 2 is integrally provided on the rear surface of the waste gate valve 1 (partition wall: the end surface opposite to the seating surface seated on the valve seat).
Details of the waste gate valve 1 will be described later.

The electric actuator includes a rod 4 that reciprocally moves in the axial direction while being coupled to the shaft 2 of the waste gate valve 1 via a link mechanism such as a link lever 3. This electric actuator performs opening / closing control of the waste gate valve 1 in accordance with the amount of movement (the stroke amount of the rod 4) of the rod 4 in the stroke axis direction (load application direction).
In addition to the rod 4, the electric actuator includes a rod bearing (thrust bearing) 6 that slidably supports the rod 4 in its reciprocating direction (the stroke axis direction of the rod 4), and a parallel axis direction of the thrust bearing 6. Coil shaft 8 for generating a biasing force (spring load) for biasing the waste gate valve 1 toward the closing side (valve full closing side) with respect to the slide shaft 7 and the rod 4 extending in a proper direction, and the rod 4 A rod stroke detection device (sensing unit 9, stroke sensor S) for detecting the stroke position of the cylinder, and an actuator case for housing components such as the thrust bearing 6 and the slide shaft 7. Here, the rod 4 of the electric actuator has its tip end side in the stroke axis direction protruding from the annular end surface of the actuator case to the outside of the actuator case.
The details of the electric actuator will be described later.

As the engine, a multi-cylinder diesel engine having a plurality of cylinders is employed. An intake pipe through which intake air flows is connected to a plurality of intake ports (for each cylinder) of the engine. A turbocharger compressor, an intercooler, a throttle valve, an intake manifold, and the like are installed in the middle of the intake pipe.
An exhaust pipe through which exhaust gas flows is connected to a plurality of exhaust ports (for each cylinder) of the engine. In the middle of the exhaust pipe, an exhaust manifold, a turbocharger turbine, and the like are installed.

The turbocharger is a turbocharger that includes a turbine and a compressor, compresses intake air by the compressor, and sends the compressed air to a combustion chamber for each cylinder of the engine.
The turbine includes a spiral turbine housing. A turbine impeller (turbine wheel) is installed in the turbine housing.
The compressor includes a spiral compressor housing. A compressor impeller (compressor wheel) is installed in the compressor housing. Further, the turbine impeller and the compressor impeller are coupled so as to rotate together by a rotor shaft.
In the turbocharger, when the turbine impeller is rotationally driven by the exhaust gas, the compressor impeller also rotates, and the compressor impeller compresses the intake air.

Here, the wastegate flow path and the wastegate valve 1 are provided in the turbine housing of the turbocharger of the present embodiment.
The waste gate flow path is a bypass passage (fluid) for allowing the exhaust gas introduced into the turbine housing to pass through the turbine impeller, that is, bypass the turbine impeller and flow to the exhaust passage downstream of the turbine impeller. Passage).
Alternatively, the waste gate flow path branches the exhaust gas flowing out from the engine from the downstream side of the exhaust manifold assembly, and joins the intake passage downstream of the turbocharger turbine in the exhaust gas flow direction. It is a bypass passage (fluid passage) for bypassing exhaust gas from the turbine housing.

The waste gate channel of the present embodiment communicates the upstream communication hole (waist gate port) opened at the partition wall at the inlet of the turbine housing and the downstream communication hole opened at the partition wall at the outlet of the turbine housing.
The waste gate valve 1 is formed in a disk shape with a metal material such as stainless steel. The waste gate valve 1 is connected to the tip of the rod 4 of the electric actuator in the axial direction, and is seated on and separated from the partition wall (valve seat) at the inlet of the turbine housing. This is an exhaust gas control valve that opens and closes the gate port.

Between the shaft 2 of the waste gate valve 1 and the rod 4 of the electric actuator, a link mechanism for converting the linear motion of the rod 4 of the electric actuator into the rotational motion of the waste gate valve 1 is installed.
In this link mechanism, as shown in FIGS. 1, 3 and 5, one end side is connected to the front end side in the load acting direction (reciprocating direction) of the rod 4 of the electric actuator, and the other end side is the waste gate valve 1. And a link lever 3 connected to the tip side of the shaft 2 (the side opposite to the valve side).
Here, a first hinge pin 11 that is driven from the back surface side of the rod 4 and protrudes to the front surface side is fixed (or integrally formed) to the distal end side in the load acting direction of the rod 4.
A second hinge pin 12 protruding in the same direction as the first hinge pin 11 is integrally formed (or fixed) on the shaft 2 of the waste gate valve 1.

The link lever 3 is rotatably supported on the outer periphery of the first hinge pin 11. The link lever 3 is fixed to the second hinge pin 12.
The first hinge pin 11 rotatably supports the waste gate valve 1, the shaft 2, the link lever 3, and the like.
The 2nd hinge pin 12 is being fixed to the electric actuator side edge part of the shaft 2 bent at right angle in the middle. The second hinge pin 12 is rotatably supported on the side wall portion of the turbine housing of the turbocharger. The center of the second hinge pin 12 is the center of rotation of the waste gate valve 1.
As described above, the waste gate valve 1 constitutes a hinge valve connected to the distal end side of the rod 4 in the load acting direction via the first hinge pin 11, the link lever 3, and the second hinge pin 12.

Next, details of the electric actuator of this embodiment will be described with reference to FIGS.
In addition to the rod 4, the thrust bearing 6 and the coil spring 8, the electric actuator includes a slide shaft 7 arranged in parallel to the rod 4, a sensing unit 9 installed integrally with the rod 4, and the sensing unit 9. A stroke sensor S that detects the stroke position of the motor, an electric motor M that generates a driving force (motor torque) upon receipt of electric power, a reduction mechanism that decelerates the rotation of the electric motor M by two stages, A conversion mechanism that converts rotational motion into reciprocating linear motion and an actuator case that accommodates these components are provided.

The reduction mechanism is composed of three reduction gears. The reduction mechanism includes a pinion gear (motor gear) 14 fixed to a motor shaft (rotary shaft, output shaft) 13 of the electric motor M, an intermediate gear (first gear) 15 that rotates in mesh with the pinion gear 14, and the intermediate gear 15. And a final gear (second gear) 16 that rotates in mesh with the gear.
The conversion mechanism includes a rotating plate cam 17, a follower 19 that is movably inserted into a cam groove 18 of the plate cam 17, and a pivot pin 20 that rotatably supports the follower 19.

Here, the actuator case of the electric actuator includes a motor housing 21 that accommodates and holds the electric motor M, a gear housing 22 that rotatably accommodates the speed reduction mechanism and the conversion mechanism, and a sensor cover that closes the opening of the gear housing 22 ( Lid) 23.
The motor housing 21 and the gear housing 22 are made of a metal material. The sensor cover 23 is formed of a metal material or a resin material.
The rod 4 of the electric actuator extends straight in the load acting direction in the same direction as the axial direction. The rod 4 is connected to the shaft 2 of the waste gate valve 1 via a first rod 24 connected (connected) to the plate cam 17 via the follower 19 and the pivot pin 20 and a link mechanism (link lever 3 or the like). The plate-shaped second rod 26 to be connected (connected), and the rotatable joint 28 that connects the first connecting portion 25 of the first rod 24 and the second connecting portion 27 of the second rod 26 are configured. These rod parts are made of a metal material (non-magnetic material) such as stainless steel.

The first rod 24 includes a plate-like input portion 31 that receives a load from the plate cam 17 via the follower 19 and the pivot pin 20 and a relay portion (connection) having a circular shape that is slidably supported by the thrust bearing 6. Rod) 32.
A fitting hole 33 into which the pivot pin 20 is fitted is formed at one end of the input portion 31 in the axial direction (the end opposite to the relay portion 32 side). The pivot pin 20 is driven from the back side of the input unit 31 and protrudes to the front side to be connected (fixed) to the input unit 31.
The surface of the input unit 31 is a sensing unit mounting surface for fixing the sensing unit 9 by resin molding or screw fastening.

Further, a guide arm 34 protrudes outward from one side surface of the input unit 31. The guide arm 34 is formed with a bearing hole 35 penetrating in the axial direction of the slide shaft 7. A thrust bearing 36 slidably supported on the outer periphery of the slide shaft 7 is press-fitted into the hole wall surface of the bearing hole 35. A through hole (sliding hole) penetrating in the axial direction of the slide shaft 7 is formed in the thrust bearing 36.
The relay part 32 is welded and fixed to the other end side of the input part 31. An annular spring seat 37, which is a load receiving portion that receives a load biased from the coil spring 8 toward the valve fully closed side in the load acting direction, is mounted on the outer periphery of the relay portion 32. Further, the relay portion 32 is formed with an outer peripheral screw 38 for fastening and fixing the rotatable universal joint 28. The outer peripheral screw 38 protrudes from the thrust bearing 6 toward the second rod 26 and is formed on the outer periphery of the columnar first connecting portion 25 connected to the rotatable joint 28.

A plate-like second connecting portion 27 connected to the rotatable joint 28 is provided at one end portion of the second rod 26 in the axial direction (end portion on the relay portion 32 side). The second connecting portion 27 is formed with a fitting hole (not shown) into which the rotatable joint 28 is fitted.
A fitting hole (not shown) into which the first hinge pin 11 is fitted is formed at the other end portion in the axial direction of the second rod 26 (end portion on the opposite side to the relay portion 32 side). The first hinge pin 11 is driven from the back surface side of the second rod 26, protrudes to the front surface side, and is connected (fixed) to the second rod 26.

The rotatable joint 28 includes a socket 41 that is fastened and fixed to the first connecting portion 25 of the first rod 24, a connecting pin 42 that is press-fitted and fixed to the second connecting portion 27 of the second rod 26, and the socket 41 and the connecting pin. And a spherical bearing installed between the two.
The socket 41 is provided with a sleeve 43 that is fitted to the outer periphery of the first connecting portion 25. A nut 44 that is screwed onto the outer peripheral screw 38 is fixed to the sleeve 43.
The connecting pin 42 is driven from the front surface side of the second connecting portion 27 and protrudes to the back surface side, penetrates the spherical bearing, and further protrudes to the back surface side of the spherical bearing, and then the tip of the protruding portion is crushed into a bowl shape. Are connected (fixed) to the second rod 26.

The spherical bearing includes a guide (outer race) 45 having a concave spherical surface on the inner periphery and a ball (spherical body, inner race) 46 having a convex spherical surface on the outer periphery. The guide 45 is integrally provided at the end of the sleeve 43 of the socket 41 on the connection pin 42 side. The guide 45 is formed in an annular shape so as to surround the periphery of the connecting pin 42 in the circumferential direction.
The convex spherical surface of the ball 46 has a predetermined radius of curvature centered on the same center point as the center of curvature of the concave spherical surface of the guide 45.
The rotatable joint 28 can swing the second connecting portion 27 about the first rod 24 and the second rod 26 about the center line perpendicular to the central axis of the first connecting portion 25 (rotatable). ). Thereby, since the shake of the second rod 26 can be absorbed, the first rod 24 does not shake in the rotation direction.

Here, a bearing hole 48 penetrating in the axial direction of the rod 4 is formed in the cylindrical bearing holder 47 positioned on the valve side from the side wall of the gear housing 22. The thrust bearing 6 is press-fitted into the hole wall surface of the bearing hole 48.
The thrust bearing 6 supports the relay portion 32 of the first rod 24 of the rod 4 so as to be slidable in the stroke axis direction (reciprocating direction). A through hole (sliding hole) penetrating in the axial direction of the rod 4 is formed in the thrust bearing 6.

Further, a fitting hole 50 penetrating in the axial direction of the slide shaft 7 is formed in a cylindrical fitting portion 49 disposed on a side wall parallel to the axial direction of the bearing hole 48 of the bearing holder 47 of the gear housing 22. Has been. The slide shaft 7 is press-fitted into the hole wall surface of the fitting hole 50.
The slide shaft 7 is driven from the inner surface side of the fitting portion 49 and connected (fixed) to the gear housing 22. The slide shaft 7 is a columnar guide rail that extends straight in a direction parallel to the axial direction of the through hole of the thrust bearing 6. A guide arm 34 integrally formed with the first rod 24 of the rod 4 is supported on the outer periphery of the slide shaft 7 through a thrust bearing 36 so as to be slidable in the axial direction of the slide shaft 7. . Thereby, the slide shaft 7 can guide the guide arm 34 of the rod 4 in a direction parallel to the stroke axis direction (reciprocating direction) of the rod 4.
As a result, the rod 4 of the electric actuator can be translated along two axes, the axial direction of the through hole of the thrust bearing 6 and the axial direction of the slide shaft 7.

A coil spring 8 is housed in a cylindrical spring holder 51 that protrudes from the side wall of the gear housing 22 toward the valve side.
The coil spring 8 is a rod (valve) urging means that generates an urging force (load) that urges the rod 4 toward the side of closing the waste gate valve 1 (valve fully closed side). One end of the coil spring 8 is held by a spring seat 37 provided on the first rod 24 of the rod 4, and the other end of the coil spring 8 is an annular connection connecting the end of the bearing holder 47 and the spring holder 51. Is held by a partition wall (closed wall) 52 of the main body.
As a result, a spring load from the coil spring 8 (a load for urging the valve fully closed) acts on the rod 4 of the electric actuator, particularly the first rod 24.

  The speed reduction mechanism constitutes a power transmission mechanism that transmits the torque of the electric motor M to the conversion mechanism. As described above, the speed reduction mechanism includes the pinion gear 14, the intermediate gear 15, the final gear 16, and the like. The speed reduction mechanism includes two first and second support shafts (intermediate gear shaft and final gear shaft) 53 and 54 that are arranged in parallel to the motor shaft 13 of the electric motor M. The intermediate gear shaft 53 and the final gear shaft 54 are arranged in parallel with each other. Further, the three gears 14 to 16 are housed rotatably in the reduction gear housing space of the gear housing 22.

  The intermediate gear shaft 53 is driven into the fitting hole of the gear housing 22 and is press-fitted and fixed to the fitting portion of the gear housing 22. The center axis of the intermediate gear shaft 53 constitutes the rotation center of the intermediate gear 15. Further, an annular circumferential groove is formed on the outer periphery of the protruding portion protruding from the end face of the intermediate gear 15 of the intermediate gear shaft 53. In this circumferential groove, a washer and a C-ring are mounted to prevent the intermediate gear 15 from coming off from the intermediate gear shaft 53 when the intermediate gear 15 is fitted on the outer periphery of the intermediate gear shaft 53.

  The final gear shaft 54 is driven into the fitting hole 55 of the gear housing 22 and is press-fitted and fixed to the cylindrical fitting portion 56. The central axis of the final gear shaft 54 constitutes the center of rotation of the final gear 16. The final gear 16 is rotatably supported on the outer periphery of the final gear shaft 54 via two bearings (bearings) 57. An annular circumferential groove is formed on the outer periphery of the protruding portion of the final gear shaft 54 that protrudes from the end face of the final gear 16. In the circumferential groove, a washer and a C-ring are mounted to prevent the final gear 16 from coming off from the final gear shaft 54 when the final gear 16 is fitted on the outer periphery of the final gear shaft 54.

The pinion gear 14 is formed of a metal material or a resin material. The pinion gear 14 is press-fitted and fixed to the outer periphery of the motor shaft 13. On the outer periphery of the pinion gear 14, a plurality of convex teeth (pinion gear portions) 61 that mesh with the intermediate gear 15 are formed in the entire circumferential direction.
The intermediate gear 15 is made of a metal material or a resin material, and is rotatably fitted to the outer periphery of the intermediate gear shaft 53. The intermediate gear 15 has a cylindrical portion installed so as to surround the periphery of the intermediate gear shaft 53 in the circumferential direction. An annular maximum outer diameter portion (large diameter portion) is integrally formed on the outer periphery of the cylindrical portion.

A plurality of convex teeth (large-diameter gear portions) 62 that mesh with the convex teeth 61 of the pinion gear 14 are formed on the outer periphery of the large-diameter portion of the intermediate gear 15 in the entire circumferential direction. A plurality of convex teeth (small-diameter gear portions) 63 that mesh with the final gear 16 are formed on the outer periphery of the cylindrical portion (small-diameter portion).
The final gear 16 is formed of a metal material or a resin material, and is rotatably fitted to the outer periphery of the final gear shaft 54 via two bearings 57. The final gear 16 has a cylindrical portion installed so as to surround the periphery of the final gear shaft 54 in the circumferential direction. This cylindrical portion has a flange 64 that extends in a fan shape from the outer peripheral surface of the cylindrical portion.
On the outer peripheral portion of the flange 64 of the final gear 16, a plurality of convex teeth (fan-shaped large-diameter gear portions) 65 that mesh with the convex teeth 63 of the intermediate gear 15 are formed in a fan shape by a predetermined angle.

The conversion mechanism is a movement direction conversion mechanism that converts the rotational movement of the final gear 16 into the linear movement of the rod 4. The conversion mechanism includes a plate cam 17 that rotates integrally with the final gear 16 around the final gear shaft 54 of the final gear 16, a follower 19 that is movably inserted into the cam groove 18 of the plate cam 17, and A pivot pin 20 or the like that rotatably supports the follower 19 is configured.
The plate cam 17 is formed in a predetermined shape from a metal material, and is fixed to the cam mounting portion of the final gear 16. When the final gear 16 is made of a resin material, the plate cam 17 is insert-molded into the final gear 16. Further, when the final gear 16 is formed of a metal material, the final gear 16 and the plate cam 17 may be integrated with sintered metal or the like. With this configuration, the rotation axis of the final gear 16 and the rotation axis of the plate cam 17 are shared, so that the rotation center of the final gear 16 (rotation center of the final gear shaft 54) and the rotation of the plate cam 17 are shared. The center matches. Further, the operating angle of the final gear 16 (final gear operating angle) is equal to the rotational angle of the plate cam 17 (cam rotational angle).

The cam groove 18 of the plate cam 17 is a curved guide portion corresponding to the operation pattern of the waste gate valve 1.
Here, the cam shape of the plate cam 17 and the rotation angle of the plate cam 17 are determined with respect to the rod stroke amount required to drive the waste gate valve 1 from the fully closed position to the fully open position.

The follower 19 is formed in a cylindrical shape from a metal material, and is rotatably fitted to the outer periphery of the pivot pin 20. The follower 19 has a cylindrical portion so as to surround the periphery of the pivot pin 20 in the circumferential direction.
The pivot pin 20 is driven into the fitting hole 33 of the rod 4 and is press-fitted and fixed to the rod 4. In addition, a flange that is crushed and crimped to prevent the follower 19 from coming off is formed on the protruding portion that protrudes from the end surface of the cylindrical portion of the follower 19 of the pivot pin 20.
Further, the rotation center of the follower 19 is installed on the load acting direction (stroke axis direction) of the rod 4 together with the rotation center of the plate cam 17.

The electric motor M is a power source for the electric actuator and is housed and held in the motor housing space of the motor housing 21. The electric motor M is configured to be energized and controlled by the ECU.
The ECU is provided with a microcomputer having a known structure that includes functions of a CPU, a ROM, a RAM, and the like. Then, the ECU performs an electric actuator for the throttle valve, a waste gate based on sensor output signals of various sensors such as a stroke sensor S, a crank angle sensor, an accelerator opening sensor, a throttle opening sensor, a boost pressure sensor, and a vehicle speed sensor. The electric actuator of the valve 1 is controlled.

The stroke sensor S constitutes a rod stroke detection device that detects the stroke position of the rod 4 together with the sensing unit 9 installed integrally with the rod 4.
First, the sensing unit 9 includes a magnetic field (a magnet) that generates a magnetic force, and a magnetic block (a magnetic body). The sensing unit 9 is integrally installed on the rod 4 by molding or screw fastening on the sensing unit mounting surface of the input unit 31 of the first rod 24 of the rod 4. Note that the sensing unit 9 may be formed of only a magnetic body by installing a magnet on the stroke sensor S side.

The stroke sensor S is installed on the sensor cover 23 so as to be positioned in the middle of the magnetic circuit formed with the sensing unit 9. The stroke sensor S includes a Hall IC installed to face the magnet or magnetic block of the sensing unit 9 and a magnetic block (magnetic material) that concentrates the magnetic flux emitted from the magnet on the Hall IC together with the magnetic block of the sensing unit 9. ) Etc.
A magnetic circuit is formed by the magnet and magnetic block of the sensing unit 9 and the Hall IC and magnetic block of the stroke sensor S.

  The Hall IC is an IC chip in which a Hall element (non-contact type magnetic detection element) that detects a magnetic field that changes in accordance with the stroke position of the sensing unit 9 and an amplifier circuit are integrated, and is connected to the Hall IC itself. A voltage signal (sensor output signal) corresponding to the intersecting magnetic flux density is output to the ECU. As a non-contact type magnetic detection element, a Hall element alone or a magnetoresistive element (MR element) may be used instead of the Hall IC. Further, a variable resistance potentiometer (contact type position detecting element) may be used as the stroke sensor S instead of the non-contact type magnetic detecting element.

  In the stroke sensor S, when the waste gate valve 1 is between the fully closed position and the fully open position, the stroke position of the sensing unit 9 (relative position with respect to the reference position) corresponds to the stroke amount of the rod 4. The stroke position of the rod 4 corresponds to the valve opening degree of the waste gate valve 1. Therefore, the ECU measures the stroke position of the sensing unit 9, that is, the sensor output signal output in response to the change of the magnetic field, determines the stroke amount of the rod 4, and determines the waste gate valve from the stroke amount of the rod 4. It is possible to obtain the valve opening of 1 and obtain the flow rate of the exhaust gas flowing through the waste gate flow path from this valve opening.

  Here, as a method of sensing the stroke position of the sensing unit 9, when performing non-contact magnetic detection using a Hall IC, a Hall element or an MR element, the sensing unit 9 and the Hall IC of the stroke sensor S If there is a magnetic body in the vicinity of the magnetic circuit constituted by the above, there is a possibility that the magnetic field detected by the non-contact type magnetic detection element cannot be secured stably. Therefore, in the electric actuator of the present embodiment, the parts (rod 4, final gear 16, plate cam 17, follower 19, pivot pin 20, final gear shaft 54) close to the sensing unit 9 are made of non-magnetic material (stainless steel or the like). By using non-magnetic metal, non-magnetic resin, etc., the influence of disturbance on the magnetic circuit is avoided.

[Operation of Example 1]
Next, the operation of the electric actuator for performing opening / closing control of the waste gate valve 1 of the present embodiment will be briefly described with reference to FIGS.

The ECU controls the power supply to the electric motor M so that the waste gate valve 1 is fully closed when the supercharging pressure detected by the supercharging pressure sensor is less than the set value.
As a result, the components of the electric actuator remain in the fully closed state shown in FIGS. 1 and 2, and the waste gate valve 1 continues to be fully closed. As a result, the waste gate channel is closed.
As a result, the entire amount of exhaust gas discharged from the engine flows from the inlet portion of the turbine housing of the turbocharger, rotates the turbine impeller, and is discharged from the outlet portion of the turbine housing.
On the other hand, the intake air sucked into the intake pipe is compressed by the compressor impeller driven by the rotation of the turbine impeller, and the pressure (supercharging pressure) increases. The intake air whose pressure has increased is sucked into the engine.

The ECU controls the electric motor so that the waste gate valve 1 is fully opened when the supercharging pressure detected by the supercharging pressure sensor rises above a set value, that is, when it exceeds a preset maximum supercharging pressure. Control power supply to M.
As a result, the motor shaft 13 of the electric motor M rotates in the fully open direction. As a result, the motor torque is transmitted to the pinion gear 14, the intermediate gear 15, and the final gear 16. Then, the plate cam 17 to which the motor torque is transmitted from the final gear 16 rotates in the fully open direction by a predetermined rotation angle (a rotation angle equal to the operation angle of the final gear 16) as the final gear 16 rotates.

Then, the pivot pin 20 slides (slids) on the cam groove 18 and moves from the fully closed position to the fully open position of the cam groove 18, so that the first rod 24 of the rod 4 compresses the coil spring 8 and the rod. 4 is linearly moved (extruded) toward the valve opening side in the load acting direction. Then, as the rod 4 moves linearly, the first connecting portion 25 of the first rod 24, the rotatable joint 28 (socket 41, spherical bearing, connecting pin 42), and the second connecting portion 27 of the second rod 26 become the rod. 4 linearly moves to the valve opening side in the load acting direction.
Further, as the second rod 26 moves linearly, the first hinge pin 11 moves linearly to the valve opening side in the load acting direction of the rod 4, so that the link lever 3 is centered on the second hinge pin 12. It rotates in the fully open direction. Then, as the second hinge pin 12 rotates, the waste gate valve 1 also rotates in the fully open direction around the second hinge pin 12. As a result, the waste gate valve 1 is detached from the valve seat and is fully opened, so that the waste gate flow path is opened.
As a result, a part of the exhaust gas flowing from the engine to the inlet portion of the turbine housing is discharged to the outlet portion of the turbine housing through the waste gate flow path that bypasses the turbine impeller. As a result, the exhaust energy acting on the turbine impeller is reduced and the rotational speed of the turbine impeller is reduced, so that the turbocharger is prevented from over-rotating.
In addition, the supercharging pressure or the exhaust pressure does not become excessive. Further, the turbine impeller is prevented from being damaged due to excessive rotation of the turbine impeller.

The ECU controls power supply to the electric motor M so that the waste gate valve 1 is fully closed when the supercharging pressure detected by the supercharging pressure sensor is lower than a set value.
As a result, the motor shaft 13 of the electric motor M rotates in the fully closed direction. As a result, the motor torque is transmitted to the pinion gear 14, the intermediate gear 15, the final gear 16, and the plate cam 17. Then, the plate cam 17 rotates in the fully closed direction by a predetermined rotation angle as the final gear 16 rotates.
Then, the pivot pin 20 slides (slids) on the cam groove 18 and moves from the fully open position to the fully closed position of the cam groove 18, whereby the rod 4 moves linearly toward the valve closing side in the load acting direction of the rod 4. Do (retracted). Then, along with the linear movement of the rod 4, the first connecting portion 25 of the first rod 24, the rotatable joint 28 (socket 41, spherical bearing, connecting pin 42), and the second connecting portion 27 of the second rod 26 become the rod 4. It moves linearly toward the valve closing side in the load application direction. Further, as the second rod 26 moves linearly, the first hinge pin 11 moves linearly toward the valve closing side in the load acting direction of the rod 4, so that the link lever 3 moves in the fully closed direction around the second hinge pin 12. Rotate to. Then, as the second hinge pin 12 rotates, the waste gate valve 1 also rotates in the fully closed direction around the second hinge pin 12. Accordingly, the waste gate valve 1 is seated on the valve seat and is fully closed, so that the waste gate flow path is closed.

[Feature 1 of Example 1]
As described above, in the electric actuator of this embodiment, as shown in FIG. 5, the linear movement of the rod 4 is performed between the shaft 2 of the waste gate valve 1 and the rod 4 of the electric actuator. A link mechanism that converts to the rotational motion of is installed. This link mechanism includes a link lever 3 having one end connected to the second rod 26 of the rod 4 via the first hinge pin 11 and the other end connected to the shaft 2 of the waste gate valve 1 via the second hinge pin 12. It is constituted by.

The link mechanism of the present embodiment includes a load acting direction (stroke axis direction) on the center line in the axial direction of the rod 4 (on the rod axis center line RC) and a center line of the operating angle of the link lever 3 (lever fully closed). This is a positional relationship (configuration) in which the hour center line LCC and the angle center line LC of the lever fully opened center line LCO) intersect perpendicularly.
As a result, the swing angle of the rod 4 due to the opening and closing of the waste gate valve 1 becomes the smallest, so when the stroke amount of the rod 4 is set to be small (the swing of the rod 4 <the backlash between the rod 4 and the thrust bearing 6), Even if the first rod 24 and the second rod 26 are formed as an integral part, the rod 4 squeezes the inner periphery of the through hole of the thrust bearing 6 and the rod 4, that is, the electric actuator becomes inoperable. Can be prevented from occurring. Further, when the stroke amount of the rod 4 is set to be large, the sliding range of the rotatable joint 28 can be reduced, so that the reliability of the rotatable joint 28 can be improved.

In the electric actuator, the sensing unit 9 is integrally installed on the rod 4 connected to the waste gate valve 1 via the link lever 3 of the link mechanism. Since the stroke position of the sensing unit 9 that moves integrally with the first rod 24 of the rod 4 is detected by the Hall IC of the stroke sensor S, the stroke position of the rod 4 that is the final operation stage of the electric actuator is directly detected. be able to. As a result, since the detection accuracy of the stroke position of the rod 4 is improved, the controllability of the stroke amount of the rod 4, that is, the controllability of the opening control of the waste gate valve 1 can be improved.
In addition, if the stroke position of the sensing unit 9 detected by the Hall IC of the stroke sensor S does not reach or approach the set target position even after a predetermined time has elapsed, a failure of the rod 4 or the electric actuator (for example, It can be determined that the waste gate valve 1 or the rod 4 is inoperable). That is, failure diagnosis of the waste gate valve 1, the rod 4 or the electric actuator can be performed. Thereby, the OBD requirement can be satisfied.

Further, in the electric actuator of the present embodiment, a thrust bearing 6 that supports the rod 4 in the stroke axial direction (reciprocating direction), and a slide shaft 7 extended in a direction parallel to the axial direction of the thrust bearing 6, It has.
When the waste gate valve 1 is driven from the fully closed position to the open position (including the intermediate position and fully open position) by the electric motor M, the speed reduction mechanism, and the conversion mechanism, or the waste gate valve 1 is closed from the fully open position. When the motor is driven to the valve position (including the intermediate position and the fully closed position), the rod 4 is translated along the two axes of the axial direction of the through hole of the thrust bearing 6 and the axial direction of the slide shaft 7. The thrust bearing 6 and the slide shaft 7 can regulate the backlash of the rod 4 in the stroke axis direction (reciprocating direction) and the swing in the rotational direction. Therefore, since the movement of the sensing unit 9 installed integrally with the rod 4 is restricted, the sensing unit 9 can be moved in a “linear” manner. As a result, the detection accuracy of the stroke position of the rod 4 can be improved.

Here, when the second rod 26 is stroked to one side (for example, the valve opening side or the valve closing side) in the stroke axis direction (reciprocating direction) and the link lever 3 is rotated, the rotation range of the link lever 3 is changed. As a result, the second rod 26 swings. For example, the second rod 26 swings in the rotational direction around its central axis.
Here, in the case where the first rod 24 and the second rod 26 are integral parts, when the second rod 26 shakes, a radial force is applied (acted) to the thrust bearing 6, and the first rod 24 is thrust. There is a possibility that the first rod 24 may become inoperable due to the inner circumference of the through hole of the bearing 6.

Therefore, in the electric actuator of this embodiment, the rod 4 is connected to the plate cam 17 via the follower 19 and the pivot pin 20, and the waste gate is connected via the link mechanism such as the link lever 3. The second rod 26 connected to the shaft 2 of the valve 1 is divided into separate parts.
A rotatable joint 28 is installed between the first connecting portion 25 of the first rod 24 and the second connecting portion 27 of the second rod 26. The rotatable joint 28 includes a socket 41 coupled to the first coupling portion 25 of the first rod 24, a coupling pin 42 coupled to the second coupling portion 27 of the second rod 26, and the socket 41 and the coupling pin 42. It is comprised by the spherical bearing etc. which were installed between.
As described above, the first rod 24 and the second rod 26 are configured as separate parts, and rotate between the first connecting portion 25 of the first rod 24 and the second connecting portion 27 of the second rod 26. By installing the universal joint 28, the vibration of the second rod 26 can be absorbed by the spherical bearing of the rotary universal joint 28. As a result, it is possible to prevent the first rod 24 from twisting the inner periphery of the through hole of the thrust bearing 6 and causing the first rod 24, that is, the electric actuator to become inoperable.

[Feature 2 of Example 1]
Here, in the electric actuator, generally, when the waste gate valve 1 is fully closed or fully opened, the side surface of the follower 19 pushes the groove side surface of the cam groove 18 of the plate cam 17 through the pivot pin 20 of the rod 4 ( (Valve reaction force) becomes a load when the motor is fully closed or fully opened.
When the load (valve reaction force) from the rod 4 acts in a direction in which the plate cam 17 is rotated in the direction of closing or opening the waste gate valve 1, the plate cam 17 rotates in the valve fully closed direction or the valve fully open direction. Since there is a possibility, in order to place the waste gate valve 1 in a stationary state in the fully open position or the fully closed position, a large amount of motor holding current is required even when the waste gate valve 1 is fully opened or fully closed.

Therefore, in the electric actuator of this embodiment, when the waste gate valve 1 is fully opened and fully closed, the load acting direction on the center line in the axial direction of the rod 4 (on the rod axis center line RC) and the cam of the plate cam 17 This is a positional relationship (configuration) in which the common tangent T direction on the contact surface between the groove side surface of the groove 18 and the side surface of the follower 19 intersects perpendicularly.
Further, the electric actuator has a positional relationship (configuration) in which the rotation center CO of the plate cam 17 and the rotation center FO of the follower 19 are on the rod axis center line RC. Further, in the electric actuator, when the valve fully closed side in the load acting direction of the rod 4 is used as a reference, that is, the follower 19 positioned on the valve fully closed side in the load acting direction of the rod 4 is the head, the follower 19 and the plate The rotation center CO of the cam 17, the relay portion 32 of the first rod 24 of the rod 4, the rotatable joint 28, and the second rod 26 are arranged in this order (configuration).

With the structure as described above, when the waste gate valve 1 is fully opened and fully closed, the force that the follower 19 inserted into the cam groove 18 through the rod 4 pushes the groove side surface of the cam groove 18 of the plate cam 17 when the motor is driven. The load acting direction on the rod axis center line RC and the common tangent T direction on the contact surface between the side surface of the cam groove 18 of the plate cam 17 and the side surface of the follower 19 intersect perpendicularly. Therefore, the load (valve reaction force) transmitted from the rod 4 to the plate cam 17 does not work in the direction in which the plate cam 17 is rotated.
Accordingly, when the waste gate valve 1 is fully opened and fully closed, the waste gate valve 1 is held at a fully open position and a fully closed position against the load (valve reaction force) transmitted from the rod 4 to the plate cam 17. Since both the motor holding current required for this can be reduced, power consumption can be suppressed.
Here, even when the waste gate valve 1 is applied to a frequently used electric actuator that drives the waste gate valve 1 to the fully closed position and the fully open position as in this embodiment, the waste gate valve 1 is fully closed and fully opened. Power consumption (current consumption) can be reduced.

Further, in the electric actuator of this embodiment, a straight line connecting the rotation center CO of the plate cam 17 and the rotation center FO of the follower 19 and a straight line connecting the rotation center CO of the plate cam 17 and the rotation center CGO of the intermediate gear 15. Is a positional relationship (configuration) that substantially matches.
Here, when the rotating shaft of the final gear 16 and the rotating shaft of the plate cam 17 are made common (configured with the same parts), the operating angle of the final gear 16 and the rotating angle of the plate cam 17 become equal. At this time, a straight line connecting the rotation center CO of the plate cam 17 and the rotation center FO of the follower 19, the rotation center of the plate cam 17 (= the rotation center of the final gear 16) CO, and the rotation center CGO of the intermediate gear 15 (= intermediate) Since the positional relationship in which the straight line connecting the convex teeth 63 of the gear 15 and the convex teeth 65 of the final gear 16 substantially coincides with each other, the final gear is within the projection plane of the operation locus of the plate cam 17. The 16 operation trajectories can be substantially matched (inserted). Therefore, the physique of the electric actuator can be reduced in size as compared with a device in which the operation locus of the plate cam 17 and the operation locus of the final gear 16 are greatly different, so that the mountability in the engine room of a vehicle such as an automobile can be improved. it can.

  FIG. 6 is a diagram showing an electric actuator for driving an EGR valve according to a second embodiment of the present invention.

The engine has an exhaust gas for recirculating EGR gas, which is part of the engine exhaust gas, from the exhaust pipe to the intake pipe for the purpose of reducing harmful substances (NOx, etc.) contained in the engine exhaust gas. An exhaust gas recirculation device (EGR device) provided with a recirculation pipe (EGR gas pipe) is installed. An exhaust gas flow control valve is installed in the middle of the EGR gas pipe.
The exhaust gas flow rate control valve includes an EGR valve 67 that variably controls the flow rate of EGR gas that flows inside the EGR gas pipe, and an electric actuator that is a valve drive device that controls opening and closing of the EGR valve 67 according to the stroke amount of the rod 4. I have.

The EGR valve 67 is a valve body that sits on and disengages from a valve seat 68 installed inside the EGR gas pipe to close and open an exhaust gas passage (EGR gas passage) 69.
Similarly to the first embodiment, the electric actuator includes a rod 4, a thrust bearing 6, a coil spring 8, an electric motor M, a reduction mechanism (three reduction gears: a pinion gear 14, an intermediate gear 15, and a final gear 16). , A conversion mechanism (plate cam 17, follower 19, pivot pin 20) and an actuator case (motor housing 21, gear housing 22, sensor cover 23) for accommodating them.

Unlike the first embodiment, the rod 4 includes only the first rod 24 having the input unit 31 and the relay unit 32. An EGR valve 67, which is a valve body of an exhaust gas flow control valve, is connected to the distal end side (first connecting portion 25 side) of the relay portion 32 of the first rod 24 in the axial direction. The EGR valve 67 is a poppet valve installed at the tip of the electric actuator rod 4 in the axial direction (load acting direction). Further, the EGR valve 67 is configured such that the back side of the disk-like portion (valve head) is seated on the valve seat 68.
The exhaust gas flow control valve may be installed at a branch portion between the exhaust passage of the exhaust pipe and the EGR gas passage 69 of the EGR gas pipe, and the intake passage of the intake pipe and the EGR gas passage 69 of the EGR gas pipe. You may install in the junction with.

  FIGS. 7 to 10 show Embodiment 3 of the present invention, and FIGS. 7 and 8 show the operating state of the electric actuator when the waste gate valve (hinge valve) is fully closed. FIG. 10 is a view showing an operating state of the electric actuator when the waste gate valve is fully opened.

On the surface of the final gear 16 of the speed reduction mechanism of the present embodiment, a fitting hole (not shown) is formed in which a first pivot pin 71 that rotatably supports the link lever 70 of the conversion mechanism is fitted. . The rod 4 of the electric actuator has a first connecting portion 25 having a circular cross section, a plate-like second connecting portion 27, and the like. A fitting hole 33 into which a second pivot pin (coupling portion of the conversion mechanism) 72 is fitted is formed on one end side in the axial direction of the first coupling portion 25.
A slide guide 5 that reciprocates (slides) on the slide shaft 7 in the axial direction is connected to the first connecting portion 25 of the rod 4 via a second pivot pin 72. A fitting hole 74 into which the second pivot pin 72 is fitted is formed in a portion overlapping the first connecting portion 25 of the slide guide 5.

  On the sensing unit mounting surface of the slide guide 5, the sensing unit 9 is integrally installed by molding or screw fastening. The sensor cover 23 is mounted with a stroke sensor S provided with a Hall IC so as to face the sensing unit 9. A guide arm 75 protrudes outward from one side surface of the slide guide 5. The guide arm 75 is formed with a bearing hole 76 penetrating in the axial direction of the slide shaft 7. Two thrust bearings 77 that are slidably supported on the outer periphery of the slide shaft 7 are press-fitted into the hole wall surface of the bearing hole 76. Inside the thrust bearing 77, a through hole (sliding hole) penetrating in the axial direction of the slide shaft 7 is formed.

A guide arm 75 formed integrally with the slide guide 5 is guided to the outer periphery of the slide shaft 7 through a thrust bearing 77 in a direction parallel to the stroke axis direction (reciprocating direction) of the rod 4. be able to.
The cylindrical portion 78 of the gear housing 22 is formed with a bearing hole 79 through which the rod 4 passes in the axial direction. 7 to 10, unlike the first and second embodiments, the rod bearing (thrust bearing 6) is not mounted. However, the back wall of the bearing hole 79 is allowed to play with the rod 4. However, you may install the bearing which supports the rod 4 slidably to the axial direction.

As in the first and second embodiments, the speed reduction mechanism of the present embodiment includes a pinion gear 14, an intermediate gear 15, a final gear 16, and the like. The central axis of the intermediate gear shaft 53 constitutes the rotation center of the intermediate gear 15. The central axis of the final gear shaft 54 constitutes the center of rotation of the final gear 16.
The conversion mechanism of the present embodiment has a link lever 70 or the like having one end connected to the final gear 16 and the other end connected to the rod 4.
Here, the first pivot pin 71 is fixed (or integrally formed) in the fitting hole of the final gear 16 so as to protrude to the surface side of the final gear 16.
A second pivot pin 72 that protrudes in the same direction as the first pivot pin 71 is integrally formed (or fixed) in the fitting hole 33 of the rod 4.
A first pin insertion hole 81 through which the first pivot pin 71 passes is formed on one end side of the link lever 70. Further, a second pin insertion hole 82 through which the second pivot pin 72 passes is formed on the other end side of the link lever 70. The link lever 70 is rotatably supported on the outer periphery of the first pivot pin 71. The link lever 70 is rotatably supported on the outer periphery of the second pivot pin 72.

  Here, the conversion mechanism such as the electric actuator, in particular, the link lever 70, operates as a reciprocating slider link even when the slide guide 5 is not installed. Corresponding to the rotation range of the link lever (the lever connecting the second connecting portion 27 of the rod 4 and the shaft 2 of the waste gate valve 1), the first and second connecting portions 25, 27 of the rod 4 are shaken. . When the sensing unit 9 is integrally installed on the rod 4 so as to detect the stroke position (movement) of the rod 4, the shake of the first and second connecting portions 25 and 27 of the rod 4 is caused by the stroke sensor S. There is a possibility of affecting the detection accuracy of the Hall IC.

  Therefore, in the electric actuator of this embodiment, the slide shaft 7 is installed in a direction parallel to the stroke axis direction (reciprocating direction) of the first and second connecting portions 25 and 27 of the rod 4, and the second pivot pin The slide guide 5 connected to the first connection portion 25 of the rod 4 is installed on the slide shaft 7 via 72, and the sensing unit 9 is installed integrally on the sensing unit mounting surface of the slide guide 5. Thus, the slide guide 5 reciprocates (slides) on the slide shaft 7 in the axial direction of the slide shaft 7. As a result, the stroke position of the rod 4 is detected by the ECU that inputs the sensor output signal from the Hall IC by detecting the stroke position of the sensing unit 9 by the Hall IC of the stroke sensor S without being affected by the deflection of the rod 4. Since the position (movement) can be detected with high accuracy, the detection accuracy of the stroke sensor S can be improved. Thereby, the controllability of the stroke amount of the rod 4 and the opening degree control of the waste gate valve 1 can be improved.

  Also in the electric actuator of the present embodiment, as in the first embodiment, the configuration of the link mechanism installed between the shaft 2 of the waste gate valve 1 and the rod 4 of the electric actuator has a structure in the axial direction of the rod 4. The center line (rod axis center line RC) and the center line LC of the operating angle of the link lever 3 are perpendicularly intersected (see FIG. 5).

  FIG. 11 shows Embodiment 4 of the present invention, and is a diagram showing an operating state of the electric actuator when the waste gate valve (hinge valve) is fully closed.

As in the third embodiment, the electric actuator of the present embodiment includes a slide guide 5 that is coupled to the first rod 24 of the rod 4 via the second pivot pin 72.
As in the third embodiment, the conversion mechanism of the present embodiment is a link lever that converts the rotation of the final gear 16 of the speed reduction mechanism into the linear motion (reciprocating movement in the stroke axis direction) of the rod 4, slide guide 5, and sensing unit 9. 70 etc.
Similarly to the first embodiment, the electric actuator includes a thrust bearing 6 that slidably supports the first rod 24 of the rod 4 in the stroke axis direction (reciprocating direction), and a through-hole of the thrust bearing 6. And a slide shaft 7 extended in a direction parallel to the axial direction.

The thrust bearing 6 is press-fitted into the hole wall surface of the bearing hole 48 of the bearing holder 47 of the gear housing 22. The slide shaft 7 is press-fitted into the hole wall surface of the fitting hole 50 of the fitting portion 49 of the gear housing 22.
As described above, in the electric actuator of the present embodiment, the thrust bearing 6 is added to the configuration of the third embodiment. Thereby, the slide guide 5, the thrust bearing 6 and the slide shaft 7 can regulate the swing in the sliding direction (stroke axis direction) and the swing in the rotation direction of the rod 4 between the rod 4 and the slide guide 5. Similarly, the detection accuracy (sensing accuracy) of the Hall IC of the stroke sensor S can be improved.

Here, as described in the first embodiment, when the second rod 26 of the rod 4 is stroked to one side in the stroke axial direction (reciprocating direction) and the link lever 3 is rotated, the rotation range of the link lever 3 is increased. Accordingly, the second rod 26 swings. When the second rod 26 is shaken, a radial force is applied (acted) to the thrust bearing 6, the first rod 24 squeezes the inner periphery of the through hole of the thrust bearing 6, and the first rod 24 operates. May become impossible.
Therefore, in the electric actuator of the present embodiment, as in the first embodiment, the rod 4 is composed of separate parts of the first rod 24 and the second rod 26, and the first connecting portion 25 of the first rod 24 A rotatable joint 28 is installed between the second connecting portion 27 of the second rod 26. The rotatable joint 28 includes a socket 41, a connecting pin 42, a spherical bearing, and the like, as in the first embodiment.
Therefore, since the vibration of the second rod 26 can be absorbed by the spherical bearing of the rotatable joint 28, the first rod 24 does not swing in the rotation direction around the axis centered on the axis. As a result, it is possible to prevent the first rod 24 from twisting the inner periphery of the through hole of the thrust bearing 6 and causing the first rod 24, that is, the electric actuator to become inoperable.

Also in the electric actuator of this embodiment, the configuration of the link mechanism installed between the shaft 2 of the waste gate valve 1 and the rod 4 of the electric actuator is the same as in the first and third embodiments. The direction center line (rod axis center line RC) and the center line LC of the operating angle of the link lever 3 are perpendicularly intersected (see FIG. 5).
As a result, the swing angle of the rod 4 due to the opening and closing of the waste gate valve 1 becomes the smallest, so when the stroke amount of the rod 4 is set to be small (the swing of the rod 4 <the backlash between the rod 4 and the thrust bearing 6), Even if the first rod 24 and the second rod 26 are formed as an integral part, the rod 4 squeezes the inner periphery of the through hole of the thrust bearing 6 and the rod 4, that is, the electric actuator becomes inoperable. Can be prevented from occurring. Further, when the stroke amount of the rod 4 is set to be large, the sliding range of the rotatable joint 28 can be reduced, so that the reliability of the rotatable joint 28 can be improved.

[Modification]
In this embodiment, the valve drive device of the present invention is applied to an electric actuator for controlling the waste gate valve that controls the opening and closing of the waste gate valve 1. However, as the valve drive device of the present invention, the rod reciprocates linearly. Alternatively, the present invention may be applied to an electric actuator for controlling a variable capacity turbocharger that is converted into a rotary motion of a valve via a lever and controls an open / close state of the valve.

Further, in this embodiment, a hinge valve or a poppet valve is employed as a valve structure driven by a valve driving device. That is, it can be configured as a valve driving device such as an electric actuator regardless of the valve structure driven by the valve driving device. In addition to the waste gate valve 1 and the EGR valve 67, it can also be used as a valve drive device such as an electric actuator for controlling a flow rate control valve for controlling a fluid flow rate. For example, the supercharging pressure may be controlled by adjusting the flow rate of the exhaust gas passing through the waste gate flow path by changing the opening of the waste gate valve 1 continuously or stepwise.
Further, as an engine, not only a diesel engine but also a gasoline engine may be used.

M Electric motor (power source)
S Stroke sensor (rod stroke detection means)
DESCRIPTION OF SYMBOLS 1 Wastegate valve 2 Wastegate valve shaft 3 Link mechanism link lever 4 Electric actuator rod 5 Slide guide 6 Thrust bearing (rod bearing)
7 Slide shaft 8 Coil spring (Rod (valve) biasing means)
9 Sensing part (rod stroke detection means)
11 First hinge pin of link mechanism 12 Second hinge pin of link mechanism 14 Pinion gear of reduction mechanism 15 Intermediate gear (first gear) of reduction mechanism
16 Final gear (second gear) of reduction mechanism
17 Plate cam of the conversion mechanism 18 Cam groove of the plate cam 19 Follower of the conversion mechanism 20 Pivot pin (rod support shaft) of the conversion mechanism
24 1st rod 26 2nd rod 28 Rotating joint 70 Link lever of conversion mechanism 71 First pivot pin of conversion mechanism 72 Second pivot pin (connection part) of conversion mechanism

Claims (11)

It has a rod that reciprocates in the axial direction,
In the valve driving device that performs opening / closing control of the valve according to the amount of movement in the stroke axis direction which is the same direction as the axial direction of the rod,
A speed reduction mechanism that decelerates the rotation of the motor that is the power source;
A conversion mechanism that converts the rotational motion of the speed reduction mechanism into linear motion of the rod;
A rod stroke detecting means having a sensing unit integrally installed on the rod, and a sensor for detecting a stroke position of the sensing unit;
Comprising:
The conversion mechanism is
A cam groove having a shape corresponding to the operation pattern of the valve; and a cam that rotates as the speed reduction mechanism rotates; and a follower that is movably inserted into the cam groove;
The rod has a support shaft that rotatably supports the follower, one end side is connected to the cam via the follower and the support shaft, and the other end side is connected to the valve,
When the valve is fully closed and fully opened, the load acting direction on the center line in the axial direction of the rod and the common tangential direction on the contact surface of the cam and the follower are perpendicular to each other. A valve driving device characterized by that. It has a rod that reciprocates in the axial direction,
In the valve driving device that performs opening / closing control of the valve according to the amount of movement in the stroke axis direction which is the same direction as the axial direction of the rod,
A speed reduction mechanism that decelerates the rotation of the motor that is the power source;
A conversion mechanism that converts the rotational motion of the speed reduction mechanism into linear motion of the rod;
A rod stroke detecting means having a sensing unit integrally installed on the rod, and a sensor for detecting a stroke position of the sensing unit;
Comprising:
The conversion mechanism is
A cam groove having a shape corresponding to the operation pattern of the valve; and a cam that rotates as the speed reduction mechanism rotates; and a follower that is movably inserted into the cam groove ;
The rod has a support shaft that rotatably supports the follower, one end side is connected to the cam via the follower and the support shaft, and the other end side is connected to the valve,
When the valve is fully closed or fully opened, the load acting direction on the center line in the axial direction of the rod and the common tangential direction on the contact surface of the cam and the follower are perpendicular to each other. ,
It is in a positional relationship where the rotation center of the cam and the rotation center of the follower are on the center line in the axial direction of the rod,
When the valve is fully closed in the load acting direction of the rod, the valve drive device is in a positional relationship in which the follower, the rotation center of the cam, and the rod are installed in this order . In the valve drive device according to claim 2,
The valve drive device according to claim 1, wherein the speed reduction mechanism includes a first gear that is rotationally driven by the motor, and a second gear that meshes with the first gear and rotates . In the valve drive device according to claim 2 or claim 3 ,
The straight line connecting the rotation center of the cam and the rotation center of the follower and the straight line connecting the rotation center of the cam and the rotation center of the first gear are substantially in a positional relationship. Valve drive device. In the valve drive device according to any one of claims 2 to 4 ,
The valve drive device according to claim 1, wherein the rod stroke detection means has a stroke detection direction of the sensing unit in a direction parallel to a stroke axis direction of the rod . In the valve drive device according to any one of claims 2 to 5 ,
A rod bearing that supports the rod in the stroke axial direction; and a slide shaft that extends in a direction parallel to the axial direction of the rod bearing,
When the valve is motor-driven from the fully closed position to the valve-opened position, or when the valve is motor-driven from the fully-open position to the valve-closed position, the conversion mechanism moves the two shafts of the rod bearing and the slide shaft. A valve driving device characterized in that the rod is translated along the same . In the valve drive device according to any one of claims 2 to 6 ,
The valve drive device according to claim 1, wherein the valve is a poppet valve installed on a distal end side of the rod in the stroke axial direction. In the valve drive device according to any one of claims 2 to 6 ,
A link mechanism that is installed between the rod and the valve and converts a linear motion of the rod into a rotational motion of the valve;
The link mechanism has a lever that connects the rod and the valve;
The rod has a first hinge pin that rotatably supports the lever ;
The valve has a second hinge pin that rotatably supports the lever;
The valve is through the first hinge pin, the lever, and the second hinge pin.
A valve drive device characterized by being a hinge valve connected to the tip end side in the stroke axial direction of the rod . In the valve drive device according to claim 8 ,
The rod has a first rod connected to the conversion mechanism and a second rod connected to the valve;
A rod bearing for supporting the first rod in the stroke axial direction;
A valve driving device comprising: a rotary joint that connects the first rod and the second rod . In the valve drive device according to claim 8 or 9 ,
2. A valve driving device according to claim 1, wherein a center line of the rod in the stroke axis direction and a center line of the operating angle of the lever are vertically crossed . In the valve drive unit according to any one of claims 2 to 10,
The sensing unit includes a magnetic body,
The component adjacent to the sensing unit is made of a non-magnetic material,
The sensor, the magnetic field is changed to the magnet occurs in response to stroke position of the sensing portion, the valve driving apparatus is characterized in that a magnetic detection element of the non-contact type for detecting a change in the magnetic field .

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