JPH0814018A - Valve actuator and engine using it - Google Patents

Abstract

PURPOSE:To regulate opening of a valve continuously and stably and simplify fail-safe at failure and the structure of an intake tube, etc. CONSTITUTION:A valve actuator comprises a shaft 22 which is arranged along the opening/closing direction of a valve 21 and has one end for attaching a valve body 21a of a valve 21 and a drive means 23 for reciprocating it in its longitudinal direction, and the drive means 23 is provided with a motor 26 and a linear movement means 27 for reciprocating the rotor 25 in the axial C direction. Screw parts 22a, 36a for shifting rotary action of the rotor 25 to reciprocating action of the shaft 22 by mutual screwing are provided in the shaft 22 and the rotor 25, a guide means 37 which suppresses its rotation and supports so as to linearly move in the axis C direction is provided in the shaft 22, and the linear movement means 27 is formed from a temperature sensing material which can be expanded/contracted according to temperature change so that the valve body 21a is operated in a fail-safe side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve actuator and an engine using the same, and more particularly, to a bypass pipe for circulating air to be supplied to a combustion chamber during idling operation or cold start of an engine of an automobile or the like. The present invention relates to an actuator suitable for adjusting the valve opening degree.

[0002]

2. Description of the Related Art Generally, an engine of an automobile or the like has a structure shown in FIG.
As shown in FIG. 7 and FIG. 7, a main intake pipe 2 for supplying air into the combustion chamber 1 is provided, and the main intake pipe 2 is for adjusting the air supply amount in conjunction with an accelerator (not shown). A throttle valve 3 (main intake air amount adjustment valve) is provided. And when the accelerator is not stepped on,
The throttle valve 3 is fully closed.

However, the accelerator is not stepped on when the engine 4 is stopped or when the engine is idling. During the idling operation, it is appropriate to maintain the idling speed of the engine 4. Air supply is needed. For this reason, conventionally, the main intake pipe 2 is provided with a bypass pipe 5 that communicates the front and rear of the throttle valve 3, and by adjusting the opening degree of the valve 6 provided in the bypass pipe 5, proper air flow during idling operation can be achieved. It is designed to maintain the supply.

That is, for example, when the cooling / heating device operates or the motor for the power steering or the power window operates during the idling operation, the load acting on the engine 4 fluctuates. Unless the amount of fuel and air are supplied, the engine 4 will stop. Therefore, it is possible to maintain a stable idling operation state by changing the air supply amount according to the load change and at the same time injecting the fuel corresponding to the supplied air amount from the injection valve 7. There is.

Further, when the temperature of the cooling water of the engine 4 before starting is extremely low in cold regions or during severe winters, it is necessary to increase the fuel supply to the combustion chamber 1 in the idling operation immediately after starting. There is. Therefore, as shown in FIG. 7, a bypass pipe 8 different from the bypass pipe 5 is provided in the main intake pipe 2 in order to secure a fuel supply amount at the time of cold start.
Is provided and the valve 9 (first idle control valve) provided in the bypass pipe 8 is opened to secure the air flow rate to the combustion chamber 1.

By the way, conventionally, the valve 6 provided in the bypass pipe 5 is provided with a valve actuator 10 composed of a solenoid, and the valve body 6a of the valve 6 is reciprocated by turning on and off the electric power supplied to the solenoid. By moving, the bypass pipe 5 was fully opened and fully closed.

However, the adjustment of the opening degree of the valve 6 by the solenoid is basically binary as described above, and by changing the duty of the supplied electric power,
Even when an appropriate opening adjustment is performed, it is necessary to maintain the opening due to a delicate balance between the elastic force of the spring and the magnetic force, and it is difficult to perform fine opening adjustment. . Particularly, since the pressure of the air flowing into the bypass pipe 5 fluctuates, it is difficult to stably arrange the valve body 6a at a fixed position. Therefore, in recent years, the bypass pipe 5
As the valve actuator 10, a system has been proposed in which a motor is used instead of the solenoid.

That is, this valve actuator 1
In No. 0, a female screw hole is formed in the rotating shaft of the motor, the male screw formed on the shaft 10a is screwed into the female screw hole, and rotation of the shaft 10a is suppressed. According to this, when the rotor is rotated by the operation of the motor and the female screw hole is rotated with the rotation of the rotor, the shaft 10a, which is prevented from rotating, causes the male screw to follow the female screw hole, It can be moved in the axial direction. Therefore, if the valve body 6a of the valve 6 is attached to the tip of the shaft 10a, the valve body 6a can be arranged at an arbitrary position by the operation of the motor and the opening degree of the bypass pipe 5 can be adjusted steplessly. Become.

[0009]

By the way, the valve actuator 10 using the motor as described above has an advantage that the opening degree of the valve 6 of the bypass pipe 5 can be adjusted steplessly. When the coil is broken, the valve 6 cannot be controlled. However,
In the normal idling operation state, the opening degree of the valve 6 is maintained, and the disadvantage is stopped to such an extent that the idling operation becomes unstable. On the other hand, in order to simplify the structure around the intake pipe 2, it is considered that the normal idle operation valve 6 having the same general function and the fast idle control valve 9 are realized by the same valve. There is.

However, in order to carry out the stepless opening adjustment, when this is realized by the valve actuator 10 using the motor as described above, the distribution area to be adjusted by the fast idle control valve 9 However, the above-mentioned inconvenience becomes serious because the flow area is much larger than the flow area to be adjusted by the valve 6 for normal idling operation.

That is, when the engine 4 is started by opening the valve of the bypass pipe largely at the time of low temperature start and the motor fails in the idling operation state, the bypass pipe is kept in the wide open state, so Fuel supply is made to an extent unthinkable in the idling operation state. Therefore, it is possible that the number of revolutions of the engine 4 becomes abnormally high. Such a situation is not preferable from the viewpoint of fail-safe design of the engine 4.

The present invention has been made in view of the above-mentioned circumstances, and adjusts the valve opening steplessly and stably, and arranges the valve body of the valve on the fail-safe side when a failure occurs. It is an object of the present invention to provide a valve actuator and an engine using the same, which is capable of simplifying the structure of the intake pipe.

[0013]

In order to achieve the above object, the present invention provides a shaft arranged along the opening / closing direction of a valve and having a valve body of the valve attached to one end thereof, and a reciprocating shaft in the longitudinal direction thereof. A motor having a stator fixed to an external structure and a rotor rotatably supported in the stator and movable in the axial direction; and the rotor. A linear movement unit that reciprocates in the axial direction with respect to the stator, and the shaft and the rotor are provided with screw portions that are screwed into each other to convert the rotational movement of the rotor into the reciprocating movement of the shaft. The shaft is provided with guide means for inhibiting the rotation thereof and supporting the shaft so as to be linearly movable in the axial direction, and the linear movement means is arranged between the stator and the rotor. Is proposed a valve actuator made of a temperature-sensitive material is caused to stretch due to temperature changes.

In the above valve actuator, it is effective if the temperature sensing material is made of a shape memory alloy and the stator and the rotor are fixed in a connected state. In addition, a cylinder chamber is provided between the stator and the rotor, the volume of which changes in accordance with the movement of the rotor in the axial direction, and the temperature sensing material is a fluid-tight sealed structure in the cylinder chamber. Good. Further, in the above valve actuator, the motor may be a stepping motor.

Further, the present invention proposes an engine in which the valve actuator is attached to a valve of a bypass pipe which communicates the front and rear of the main intake air amount adjusting valve of the intake pipe. In this engine, it is effective to provide a flow path for circulating the fluid inside the engine, the temperature of which rises with the operation of the engine, around the linear movement means.

[0016]

According to the valve actuator of the present invention, the shaft is reciprocally moved in the longitudinal direction by the operation of the drive means, and the valve element of the valve attached to one end of the shaft is moved in the opening / closing direction of the valve. In this case, when the motor of the driving means is operated, the rotor of the stator fixed to the external structure is rotated around the axis. Since the rotor and the shaft are provided with screw portions that are screwed into each other, the rotation of the rotor is converted into reciprocating movement of the shaft by the screw portions.
As a result, the position of the valve element can be changed according to the rotation angle of the rotor, and the opening degree of the valve can be set arbitrarily.

When the linear moving means of the driving means is actuated, the rotor is reciprocally moved in the axial direction with respect to the stator, and the moving range of the valve element by the motor is shifted in the axial direction. Become. In this case, since the linear moving means is made of the temperature sensing material, it is possible to change the moving range of the valve body according to the temperature change.
Therefore, in any facility or device in which the valve is installed, the valve body of the valve is shifted to the closing direction or the opening direction according to the temperature change of the working fluid, etc., and the fail-safe design or the automatic adjustment design is easily performed. It becomes possible.

Further, if the temperature sensing material is made of a shape memory alloy that connects the stator and the rotor, the temperature sensing material expands and contracts due to temperature changes, and the position of the rotor with respect to the stator changes in accordance with the expansion and contraction. Is possible. Further, between the stator and the rotor, a cylinder chamber whose volume is changed according to the movement of the rotor in the axial direction is provided, and the temperature sensing material is composed of a fluid sealed in a liquid-tight state in the cylinder chamber. Then, the volume of the temperature sensing material made of fluid changes with the temperature change, and the volume of the cylinder chamber is changed, so that the rotor is moved in the axial direction with respect to the stator. Also,
If the motor is a stepping motor, open loop control can be adopted, the control system can be simplified, and cumulative error can be reduced to perform highly accurate valve opening adjustment.

According to the engine of the present invention, the opening degree of the valve of the bypass pipe is adjusted by the valve actuator having the above structure. Therefore, since the flow area of the bypass pipe is adjusted steplessly and stably, it becomes possible to circulate a desired flow rate of air, and at the same time, the opening degree is maintained so as not to be changed by the air flow. Become. As a result, an appropriate amount of air can be circulated according to the load change of the engine, so that the idling operation can be stably maintained.

Further, since the reciprocating movement of the valve by the motor is carried out during the normal idling operation, and the reciprocating movement of the rotor by the linear moving means can be carried out during the idling operation at the cold start, the bypass pipe and the valve Is unified and the structure of the intake pipe is simplified. In this case, if the linear movement means is a temperature sensing material, the opening of the bypass pipe is set to a small value during normal idling operation when the engine is warm, so even if the motor fails, the rotation in idling operation It is possible to prevent an abnormal increase in the number.

Further, in the above engine, there is provided a flow passage for circulating a fluid in the engine whose temperature rises with the operation of the engine, such as a fluid such as cooling water, lubricating oil and exhaust gas, around the linear moving means. By doing so, it becomes possible for the linear movement means to reliably detect the temperature condition of the engine.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a valve actuator and an engine using the same according to the present invention will be described below with reference to FIGS. As shown in FIG. 1, a valve actuator 20 according to the present embodiment includes a rod-shaped shaft 22 to which a valve body 21a of a valve 21 is attached at its tip,
It is composed of a drive means 23 for moving the shaft 22 in its longitudinal direction.

The driving means 23 includes a stepping motor 26 having a stator 24 and a rotor 25, and a linear moving means 27 for reciprocating the rotor 25 of the stepping motor 26 in the axial direction of the stator 24.
Is provided. The stator 24 of the stepping motor 26 is composed of a casing 28 fixed to an external structure such as an engine bypass pipe, which will be described later, and a bobbin 29 arranged inside the casing 28. The bobbin 29
Are formed in an annular shape that accommodates the coil 30 formed in an annular shape, and are arranged side by side in the direction of the axis C.

As shown in FIG. 3, each bobbin 29 is provided with a plurality of trapezoidal pole teeth 29a, 29b arranged in the circumferential direction so as to form the inner peripheral surface thereof in an array state. The pole teeth 29a and 29b are provided so as to alternately have different magnetic poles along the circumferential direction. Further, the coil 30 is composed of two windings for each bobbin 29, and the pole teeth 29a.
The magnetic pole appearing at 29b can be changed.

Further, the rotor 25 is constructed such that a plurality of strip-shaped magnetic poles 31 along the axis C direction are arrayed in the circumferential direction on the outer peripheral surface formed in a cylindrical shape. The magnetic poles 31 of the rotor 25 are magnetized so as to have different magnetic poles alternately in the circumferential direction, and the pole teeth 29a and 29 of the stator 24 are magnetized.
It is arranged so as to form a ring-shaped minute gap with b. The rotor 25 thus formed includes a flange 32 fixed to the casing 24 and a casing 28.
It is rotatably attached via a bearing 35 to a sliding housing 34 which is movably supported in the direction of the axis C by a cylindrical sliding bearing portion 33 provided on the inner surface.

Further, the rotor 25 is provided with a center hole 36 formed at the center thereof along the direction of the axis C, and inside the center hole 36, a female screw 36a (screw portion) is formed. Has been formed. Further, the shaft 22 is provided on its outer peripheral surface with a male screw 22a (screw portion) that is screwed into the female screw 36a of the rotor 25, and a guide groove 22b formed along the longitudinal direction. A key member 32a provided on the flange 32 is inserted and arranged in the guide groove 22b. The key member 32a and the guide groove 22b constitute guide means 37 for guiding the movement of the shaft 22.

By engaging the key member 32a with the groove wall of the guide groove 22b, the guide means 37 suppresses the rotation of the shaft 22 which is about to be rotated along with the rotation of the rotor 25, and the guide groove 22b. Only the movement of the shaft 22 in the direction of the axis C along the axis is allowed. Therefore, the rotational force of the stepping motor 26 is converted into a propulsive force for moving the shaft 22 in the direction of the axis C by the male screw 22a and the female screw 36a screwed together, and the shaft 22 is guided by the guide means 37. It is possible to reciprocate in the direction of the axis C.

The linear moving means 27 is a temperature sensing material made of a material such as a shape memory alloy, and is formed in a coil spring shape, for example. The linear moving means 27 is provided with a recess 38 of a heat transfer block 38 provided between a sliding housing 34 supporting the rotor 25 and a casing 28.
The heat transfer block 38 and the sliding housing 34 have both ends fixed to the heat transfer block 38 and the housing 38. Therefore, when the linear moving means 27 is heated and the temperature rises, the linear moving means 27 is deformed in a direction extending in the axis C direction and linearly moves the rotor 25 with respect to the stator 24 in one direction along the axis C direction. When the temperature drops, the rotor 25 can be linearly moved in the opposite direction.

The heat transfer block 38 is made of a material having a high heat conductivity such as aluminum.
A conduit 39 (flow path) made of a copper pipe or the like is embedded in the inside thereof. The conduit 39 is the linear movement means 2
It is arranged so as to surround the concave portion 38a accommodating 7 and allows the cooling water for the engine to be described later to flow therethrough. As a result, the temperature of the cooling water is immediately detected by the linear moving means 27 via the conduit 39 and the heat transfer block 38. 1 and 2, reference numeral 40 denotes a terminal for energizing the coil 30,
Reference numeral 41 is a spring for eliminating backlash between the male screw 22a of the shaft 22 and the female screw 22a of the rotor 25.

The valve actuator 20 formed in this way can be used, for example, as shown in FIG.
It is used by being attached to the valve body 21a of the valve 21 provided in the bypass pipe 44 of the intake pipe 43. That is, for example, in a cold region or in a severe winter season, when the cooling water is cold before the engine 42 is started, the cooling water in the pipe 39 of the heat transfer block 38 is also in a low temperature state, and the linear moving means is used. 27 is contracted by sensing the low temperature state. Therefore, the rotor 25 is arranged in a state of being moved in the direction of retracting the shaft 22, and the valve body 21a attached to the tip of the shaft 22 is arranged in a position where the valve 21 is wide open.

When the engine 42 is started, a large amount of air is supplied through the bypass pipe 44 with the valve 21 widely opened, and a large amount of fuel is injected into the combustion chamber 45 according to the supplied air amount. As a result, a good combustion state is secured. Therefore, a stable idling operation state is achieved even at the time of cold start.

When the idling operation at the time of starting is continued and the cooling water of the engine 42 is warmed up, the heat is detected by the linear moving means 27 via the pipe 39 and the heat transfer block 38, and this is detected. According to the linear moving means 2
7 is expanded, and the rotor 25 is moved in the direction in which the shaft 22 is projected from the casing 28. Therefore, the valve body 21a is moved so as to reduce the opening degree of the valve 21 of the bypass pipe 44, and the supply air amount is reduced. As a result, the rotation speed of the engine 42 is reduced, and the engine 42 enters a normal idling operation state.

In this case, when the load on the engine 42 changes due to the operation of a cooling / heating device (not shown), power steering, etc., the coil 30 of the stepping motor 26 is energized accordingly, and the rotor 25 is rotated at an appropriate angle. Is rotated. Then, the female screw 36a of the rotor 25
The shaft 22 having the male screw 22a screwed into is linearly moved while being guided in the direction of the axis C by the guide means 37, and the position of the valve body 21a is displaced.

That is, by operating the stepping motor 26, the opening degree of the valve 21 is adjusted so as to achieve an appropriate supply air amount according to the load fluctuation, and the idling operation state is stably maintained. In this case,
Since the valve body 21a is moved by the stepping motor 26, its position can be finely changed. Therefore, it is possible to realize a slight change in the opening degree and achieve a good idling operation state.

As described above, the shaft 22 applies the rotational force of the stepping motor 26 to the female screw 36a and the male screw 2.
2a and is linearly moved in the direction of the axis C. Therefore, the shaft 22 is moved from the air flow via the valve body 21a.
The pressure applied to the stepping motor 26 is received by the screws 36a and 22a, and is held so that the reverse torque is not applied to the stepping motor 26. Thereby, the valve body 21
The position of a is stably maintained so as not to change due to the airflow, and a stable idling operation state can be maintained.

Next, in the valve actuator 20 of this embodiment, the case where the stepping motor 26 fails due to the disconnection of the coil 30 will be described below. First, in a normal idling operation state, when the stepping motor 26 fails, the valve body 21a becomes uncontrollable, so that a good idling operation state cannot be maintained. Therefore, when a load change occurs in the engine 42, the idling operation may stop.

On the other hand, when the load of the engine 42 fluctuates in the direction of lightening, it is conceivable that the rotational speed of the engine 42 may slightly increase. However, according to the valve actuator 20 of the present embodiment, when the stepping motor 26 fails, the valve body 21a is stopped at that position, so that the rotation speed of the engine 42 is abnormally increased. The situation is avoided.

Further, even when the stepping motor 26 fails in the idling operation state at the time of cold start, the valve element 2 by the stepping motor 26 is similarly operated as described above.
Since the control of 1a becomes impossible, it becomes difficult to maintain a good idling operation state according to the load fluctuation. Here, if the above failure occurs with the valve 21 wide open, a large amount of air will flow into the combustion chamber 45, but since the engine 42 is in a low temperature state,
The number of rotations does not become abnormally high. When the idling operation progresses and the cooling water of the engine 42 warms up, the temperature sensing material, which is the linear moving means 37, senses the temperature change and expands. It becomes the idling operation state.

That is, according to the valve actuator 20 of the present embodiment, even if a failure occurs in the stepping motor 26 during idling operation at the time of cold start, it is possible to avoid an abnormal increase in the rotational speed of the engine 42. be able to. Therefore, the actuator for the valve and the fast idle control valve used for the normal idling operation can be realized by the single valve actuator 20, so that the intake pipe 43
The surrounding structure can be simplified.

Next, a second embodiment of the valve actuator according to the present invention will be described with reference to FIG. The valve actuator 50 of this embodiment is different from the valve actuator 20 of the first embodiment in the linear movement means 51.

In the linear moving means 51 of the valve actuator 20 of this embodiment, the sliding housing 34 is provided with a convex portion 52 which is fitted in the concave portion 38a provided in the heat transfer block 38, and the concave portion 38a is formed. A fluid 54 made of a material such as wax is enclosed in a cylinder chamber 53 defined by the convex portion 52 and the convex portion 52. The sliding portion between the concave portion 38a and the convex portion is closed in a liquid-tight state by a packing 55 so that the fluid 54 sealed in the cylinder chamber 53 does not leak to the outside of the cylinder chamber 53.

According to the valve actuator 20 constructed as described above, when the temperature of the cooling water is low, the fluid 54 is contracted and the volume of the cylinder chamber 53 is reduced. The shaft 22 is moved in a direction in which it is retracted into the casing 28. When the cooling water is heated, the heat is transferred to the fluid 54 in the cylinder chamber 53 via the heat transfer block 38, and the volume of the fluid 54 increases. As a result, the sliding housing 34 is pressed in the direction in which the volume of the cylinder chamber 53 increases, that is, in the direction in which the shaft 22 projects from the casing 28, and the valve body 21a is moved in the direction in which the valve 21 is closed. Become.

When the engine 42 is stopped and the temperature of the cooling water decreases, the volume of the fluid in the cylinder chamber 53 decreases, so that the sliding housing 34 moves the shaft 22 into the casing 2 by the pressure balance inside and outside the cylinder chamber 53.
It will be moved in the direction of withdrawing into 8. Therefore, the valve actuator 50 of the present embodiment can also achieve the same effect as the valve actuator 20 of the first embodiment.

Although the valve actuators 20 and 50 in the first and second embodiments are applied to the valve 21 of the bypass pipe 44 of the engine 42, the invention is not limited to this. It may be applied to the case of driving any of the valves. Further, in place of the fluid such as the shape memory alloy or wax adopted as the linear moving means 27, 51, any material of which shape or volume is changed with temperature change can be adopted.

Further, as the temperature rises, the shaft 2
Although the valve actuators 20 and 50 that project 2 are described, a valve actuator that retracts the shaft 22 can be configured instead. In this case, in the shape memory alloy, the relationship between the temperature and the length is reversed, and when a fluid such as wax is used, a piston is provided instead of the convex portion 52, If the fluid 54 is enclosed on the side, it is possible to easily cope with the situation.

Further, a female screw 25a is provided on the rotor 25,
Although the male screw 22a screwed to this is provided on the shaft 22, the configuration may be reversed. Further, the material of the heat transfer block 38 or the like is not particularly limited, and instead of the fluid circulating in the pipe 39 being cooling water, for example, in the engine 42 in which the temperature of lubricating oil or the like changes. Other fluids may be adopted.

[0047]

As described above in detail, the valve actuator according to the present invention includes a shaft which is arranged along the opening and closing direction of the valve and which has a valve body attached to one end thereof.
A driving means for reciprocating this in the longitudinal direction thereof, the driving means comprising a motor and a linear moving means for reciprocating the rotor in the axial direction, and the rotor being screwed onto the shaft and the rotor. The screw part that converts the rotating motion of the to the reciprocating motion of the shaft is provided, and the shaft
Since the guide means for suppressing the rotation and supporting the linear movement in the axial direction is provided, and the linear movement means is constituted by the temperature sensing material which can be expanded and contracted by the temperature change,
Within the range of reciprocating movement by the motor, the valve element is finely moved to adjust the valve opening steplessly, and the valve opening is changed according to the temperature change. The effect that the valve body can be moved to the fail-safe side is achieved.

In the above valve actuator, if the temperature sensing material is made of a shape memory alloy and the stator and the rotor are connected to each other, the rotor can be moved to an arbitrary position by the deformation of the shape memory alloy. Therefore, the above effect can be achieved with a simple configuration.

Further, between the stator and the rotor, a cylinder chamber whose volume is changed according to the movement of the rotor in the axial direction is provided, and the temperature sensing material made of fluid is sealed in the cylinder chamber in a liquid-tight state. Also has the same effect as the above effect.

Further, if the motor is configured by a stepping motor, the control system can be simplified and the cost can be reduced, and the cumulative error can be reduced by the open loop control to adjust the valve opening accurately. It has the effect of being able to.

Further, according to the engine of the present invention, since the valve actuator is attached to the valve of the bypass pipe that communicates the front and rear of the main intake air amount adjusting valve of the intake pipe, it is used for normal idling operation. The valve and the fast idle control valve can be opened and closed by one actuator, and the structure around the intake pipe can be simplified. Moreover, fine opening adjustment as described above can be performed during normal idling operation to maintain a good idling operation state, and even if the motor fails during idling operation at cold start. It is possible to prevent the engine speed from increasing abnormally.

Further, in the above-mentioned engine, if the flow path for circulating the fluid inside the engine, the temperature of which rises with the operation of the engine, is provided around the linear moving means, the operating state of the engine is made sensitive to the linear moving means. Since the detection is performed, there is an effect that the opening degree can be adjusted more reliably.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a first embodiment of a valve actuator according to the present invention.

FIG. 2 is a schematic diagram for explaining an internal structure of a motor of the valve actuator of FIG.

FIG. 3 is a vertical cross-sectional view showing a state in which the linear moving means is operated and the valve body is moved in the valve actuator of FIG.

FIG. 4 is a schematic diagram showing an embodiment of an engine according to the present invention to which the valve actuator of FIG. 1 is applied.

FIG. 5 is a vertical cross-sectional view showing a second embodiment of the valve actuator according to the present invention.

FIG. 6 is a schematic diagram showing a normal idling operation state of a conventional engine in which two valves are installed side by side.

FIG. 7 is a schematic diagram showing an idling operation state when the engine of FIG. 6 is cold started.

[Explanation of symbols]

 C axis 3 Throttle valve (main intake amount control valve) 20/50 Valve actuator 21 Valve 21a Valve body 22 Shaft 22a Male screw (screw part) 23 Drive means 24 Stator 25 Rotor 26 Stepping motor (motor) 27/51 Linear movement Means 36a Female screw (screw portion) 37 Guide means 39 Pipe line (flow passage) 42 Engine 44 Bypass pipe (external structure) 53 Cylinder chamber 54 Wax (fluid)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takanori Okawa 1-297 Kitabukurocho, Omiya City, Saitama Prefecture Mitsubishi Materials Corporation Mechatronics & Production System Development Center

Claims (6)

[Claims] 1. A shaft, which is arranged along an opening / closing direction of a valve and has a valve body of the valve attached to one end thereof, and a drive means for reciprocating the shaft in the longitudinal direction thereof. The drive means is an external structure. A motor having a stator fixed to the stator, a rotor rotatably supported in the stator so as to be movable in the axial direction, and linear moving means for reciprocating the rotor in the axial direction with respect to the stator. The shaft and the rotor are provided with a screw portion that is screwed into each other to convert the rotational movement of the rotor into the reciprocating movement of the shaft, and the shaft is prevented from rotating and is linearly movable in the axial direction. A temperature sensing material that is provided with a guide means for supporting the linear movement means, is disposed between the stator and the rotor, and is expanded and contracted by a temperature change. Valve actuator, characterized in that Li Cheng. 2. The valve actuator according to claim 1, wherein the temperature sensing material is made of a shape memory alloy, and the stator and the rotor are fixed in a connected state. 3. A cylinder chamber is provided between the stator and the rotor, the volume of which changes with the axial movement of the rotor, and the temperature sensing material is sealed in a liquid-tight state in the cylinder chamber. The valve actuator according to claim 1, wherein the valve actuator comprises a fluid. 4. The valve actuator according to claim 1, wherein the motor is a stepping motor. 5. The valve actuator according to any one of claims 1 to 4, wherein the valve actuator is attached to a valve of a bypass pipe that communicates the front and rear of the main intake air amount adjusting valve of the intake pipe. engine. 6. The engine according to claim 5, further comprising a flow passage for circulating a fluid inside the engine, the temperature of which rises with the operation of the engine, around the linear movement means.