JP5145187B2 - Intake device for internal combustion engine - Google Patents

Description

  The present invention relates to an intake device for an internal combustion engine that opens and closes an air flow path communicating with a combustion chamber of the internal combustion engine, and more particularly to an intake device for an internal combustion engine that controls intake air supplied to the combustion chamber of the internal combustion engine.

[Conventional technology]
2. Description of the Related Art Conventionally, as an intake device for an internal combustion engine, a throttle device that adjusts the flow rate (intake air amount) of intake air supplied to a combustion chamber of the internal combustion engine has been proposed (see, for example, Patent Document 1). As shown in FIGS. 8 to 11, the throttle valve used in the throttle device of the internal combustion engine is a disc-like shape in which a metal shaft 102 is insert-molded in the axial direction portion of the valve body 101 made of synthetic resin. A butterfly type resin mold valve (butterfly valve) is used.

  Here, the synthetic resin butterfly valve (conventional example 1) shown in FIGS. 8 and 9 is centered around the rotation shaft in the throttle bore (air flow path) 104 of the synthetic resin or metal throttle body 103. And is rotatably housed. This butterfly valve has a tapered cross-sectional shape in which the cross-sectional shape in the direction perpendicular to the rotation axis direction gradually decreases in thickness from the shaft 102 toward the outer peripheral end. In other words, the butterfly valve has a tapered cross-sectional shape in which both front and back side surfaces of the valve main body 101 are symmetrically inclined from the axial direction portion where the shaft 102 is insert-molded toward the outer peripheral end surface. Further, on both front and back side surfaces of the valve body 101, a plurality of rectifying ribs 105 extending in a direction perpendicular to the rotation axis direction and inclined along the respective tapered surfaces are provided.

  A tapered surface (slit) 106 having a predetermined taper angle is formed between the adjacent rectifying ribs 105. As shown in FIG. 8, the outer peripheral edge of the valve main body 101 is formed with an outer peripheral edge 107 that is gently inclined along the outer periphery of the valve main body 101 with a constant width. A flat surface without an inclination is formed between the outer peripheral edge 107 and the end of each tapered surface 106. Further, when the surface of the valve main body 101 shown in FIG. 8 is the front side surface of the valve main body 101, the butterfly valve is formed in the same shape as the front side surface of the valve main body 101. .

  The butterfly valve (conventional example 2) shown in FIGS. 10 and 11 has a tapered cross-sectional shape in which the cross-sectional shape in the direction perpendicular to the rotational axis direction gradually decreases in thickness from the shaft 102 toward the outer peripheral end. It has become. Further, the butterfly valve is provided with grooves 108 that extend in the direction perpendicular to the rotation axis direction through the valve center (the central portion of the throttle bore 104 when the valve is fully opened) on both the front and back sides of the valve body 101. The groove 108 is formed between the two rectifying ribs 105 as shown in FIG. Further, at the central portion of the groove 108, a part of the outer peripheral surface of the shaft 102 is exposed. However, the wall thickness of the valve body 101 at the exposed portion is substantially the same as the outer diameter of the shaft 102 as shown in FIG.

  As described above, the synthetic resin butterfly valve described in Patent Document 1 (conventional examples 1 and 2) is characterized by an axial portion (valve body) that covers the outer periphery of the shaft 102 and extends in the rotational axis direction. The taper surfaces 106, the rectifying ribs 105, and the grooves 108 extending in the direction perpendicular to the rotation axis direction of the shaft 102 are formed on the front and back side surfaces of the valve body 101. Thus, when the butterfly valve is viewed from the side, a streamline shape such as a substantially rhombus is formed. Therefore, when the butterfly valve is fully opened in the throttle bore 104 of the throttle body 103, the flow of the intake air on both the front and back sides of the valve body 101 is parallel to the throttle bore 104 and is disturbed by the butterfly valve. Will not occur. As a result, the pressure loss when the butterfly valve is fully opened can be reduced, and the air flow rate when the butterfly valve is fully opened, that is, the fully open flow rate can be increased.

[Conventional technical problems]
However, in the synthetic resin butterfly valve described in Patent Document 1 (conventional examples 1 and 2), the thickness of the valve body 101 in the axial direction, that is, the thickness of the resin near the shaft increases. Voids are likely to occur inside the axial portion, that is, inside the resin near the shaft.
For this reason, since the holding pressure is not sufficiently applied to the molten resin injected and filled in the cavity due to the volume difference between the gate and the cavity of the resin mold for injection molding the butterfly valve, the molding shrinkage of the valve body 101 is stabilized. Therefore, the dimensional accuracy of the valve body 101 deteriorates. Further, the resistance to cold and heat decreases due to the difference in coefficient of linear expansion between the synthetic resin valve body 101 and the metal shaft 102, and the valve body 101 is peeled off from the shaft 102 or near the interface between the valve body 101 and the shaft 102. Tends to be the starting point of resin cracking, and there is a problem that quality is deteriorated.

In addition, in a throttle device for an internal combustion engine, a negative pressure (intake negative pressure lower than atmospheric pressure) generated downstream of the butterfly valve is applied to the butterfly valve, or burns in a combustion chamber of the internal combustion engine other than normal combustion There is a possibility that pressure fluctuation caused by (backfire) may be applied to the butterfly valve. For this reason, in the case of a butterfly valve in which a metal shaft 102 is insert-molded in the axial direction portion of the valve body 101 made of synthetic resin, it is not possible to secure a strength that can withstand excessive pressure such as suction negative pressure or backfire. There is sex.
These effects are considered to be more noticeable as the diameter of the disc-shaped butterfly valve (valve body 101) increases.
JP 2007-127191 A

  An object of the present invention is to provide an intake device for an internal combustion engine capable of ensuring strength and improving quality without impairing the fully opened flow rate performance.

According to the first aspect of the present invention, the butterfly valve that controls the air supplied to the combustion chamber of the internal combustion engine by opening and closing the air flow path is constituted by a metal shaft and a resin valve body. . And the cross section perpendicular | vertical to the direction (perpendicular | vertical direction with respect to a rotating shaft direction) orthogonal to the axial direction of the axial direction part of a valve | bulb main body is formed in the streamline shape.
As a result, when the butterfly valve is fully opened in the duct, the air flow on both the front and back sides of the valve body is parallel to the air flow path, and the air is not disturbed by the axial direction portion of the butterfly valve. As a result, the pressure loss when the butterfly valve is fully opened can be reduced, so that the air flow rate when the butterfly valve is fully opened, that is, the fully open flow rate can be increased.

In addition, a first slit extending in a direction orthogonal to the axial direction of the axial portion from the axial portion toward the outer peripheral end is formed on the front side surface of the valve body, and the axial portion is formed on the back side surface of the valve body. A second slit extending in a direction perpendicular to the axial direction of the axial portion from the outer periphery toward the outer peripheral end is formed. Then, the valve body, the center line of the slit width direction of the first slit is offset arranged with respect to the center line of the slit width direction of the second slit.
As a result, compared with the case where the slit position formed on the front side surface of the valve body and the slit position formed on the back side surface of the valve body are opposed to each other, the inside of the resin valve body, that is, the inside of the resin The diameter of the contact circle is reduced, the thickness of the resin valve body in the axial direction, that is, the thickness of the resin near the shaft is reduced, and voids generated by the thickness can be reduced. As a result, the cross-sectional shape of the valve body maintains the streamline shape with low resistance to the flow of air supplied to the combustion chamber of the internal combustion engine, while maintaining the axial thickness of the resin valve body, that is, near the shaft By reducing the resin wall thickness, it is possible to secure the strength and improve the quality of the resin valve body without impairing the fully opened flow rate performance.

According to the second aspect of the present invention, the center line in the slit width direction of the first slit is offset from the center line in the slit width direction of the second slit so as to be closer to one side in the axial direction of the axial portion. Yes. As a result, the cross-sectional shape of the valve body maintains the streamline shape with low resistance to the flow of air supplied to the combustion chamber of the internal combustion engine, while maintaining the thickness of the axial portion of the resin valve body, that is, near the shaft By reducing the resin wall thickness, the strength of the resin valve body can be secured and the moldability and quality can be improved without impairing the fully opened flow rate performance.
According to the third aspect of the present invention, the butterfly valve is a resin molded valve that covers the shaft in the axial direction of the valve body.

According to the fourth aspect of the present invention, the first tapered surface inclined downward from the axial direction portion toward the outer peripheral end is formed on the front side surface of the valve body, and the axial direction portion is formed on the back side surface of the valve body. A second tapered surface inclined downward toward the outer peripheral end is formed. This maintains the cross-sectional shape with low resistance to the flow of air supplied to the combustion chamber of the internal combustion engine, and does not impair the fully open flow rate performance.
According to the fifth aspect of the present invention, the first tapered surface on the front side surface of the valve body is formed with a plurality of first slits provided at predetermined intervals along the axial direction of the axial direction portion, and the valve A plurality of second slits provided at predetermined intervals along the axial direction of the axial portion are formed in the second tapered surface on the back side surface of the main body. As a result, the cross-sectional shape of the valve body maintains the streamline shape with low resistance to the flow of air supplied to the combustion chamber of the internal combustion engine, while maintaining the thickness of the axial portion of the resin valve body, that is, near the shaft By reducing the resin wall thickness, the strength of the resin valve body can be secured and the moldability and quality can be improved without impairing the fully opened flow rate performance.

According to the sixth aspect of the present invention, the valve body has a plurality of first tapered surfaces which are partitioned from each other by the plurality of first slits and are provided at predetermined intervals along the axial direction of the axial portion. doing. The valve main body has a plurality of second tapered surfaces which are partitioned from each other by a plurality of second slits and provided at predetermined intervals along the axial direction of the axial direction portion.
The slit width of at least one first slit of the plurality of first slits is narrower than the surface width of at least one first tapered surface of the plurality of first tapered surfaces, and the plurality of second slits. The slit width of at least one second slit is narrower than the surface width of at least one second tapered surface of the plurality of second tapered surfaces.
As a result, the valve made of resin compared to the type in which the slit width of the first slit is wider than the surface width of the first tapered surface and the slit width of the second slit is wider than the surface width of the second tapered surface. Since the effect of reducing the thickness of the axial portion of the main body, that is, the resin thickness in the vicinity of the shaft is large, the amount of voids generated can be further reduced.

According to the seventh aspect of the present invention, the distance between the first taper surface and the second taper surface is a, the slit wall surface on one side of the slit width direction of the first slit and the slit width direction of the second slit. When the distance between the slit wall surface on the other side is b, the relationship of a> b is satisfied.
As a result, the effect of reducing the wall thickness in the axial direction of the valve body made of resin, that is, the resin wall thickness in the vicinity of the shaft is greater than that set in the relationship of a ≦ b. It can be further reduced.

  The best mode for carrying out the present invention has a shape with low resistance to the flow of air supplied to the combustion chamber of the internal combustion engine, with the aim of ensuring strength and improving the quality without impairing the full flow rate performance. This was achieved by reducing the resin wall thickness near the shaft while maintaining it. Specifically, a cross-sectional shape of the valve body, that is, a cross-section perpendicular to the direction perpendicular to the axial direction of the axial portion is formed in a streamline shape. The position of the first slit formed on the front side surface of the valve body is offset with respect to the position of the second slit formed on the back side surface of the valve body.

[Configuration of Example 1]
FIGS. 1 to 7 show Embodiment 1 of the present invention, FIGS. 1 and 2 show an electronic throttle device for an internal combustion engine, and FIGS. 3 and 4 show a butterfly valve made of synthetic resin. It is a figure.

  The internal combustion engine (engine) of the present embodiment is equipped with an air cleaner, an electronic throttle device, and the like. Moreover, the engine is mounted in the engine room of a car, for example. Here, the engine outputs engine output (for example, engine output) by thermal energy obtained by burning a mixture of clean intake air filtered by an air cleaner (air cleaner of an internal combustion engine) and fuel injected from an injector in a combustion chamber. This is a gasoline engine that obtains (shaft torque = engine torque).

  The engine also includes an intake duct (intake duct, intake pipe) for introducing intake air into the combustion chamber of each cylinder of the engine, and exhaust gas from the combustion chamber of each cylinder of the engine via an exhaust purification device. And an exhaust duct (exhaust duct, exhaust pipe). An intake passage is formed inside the intake duct for introducing clean outside air (clean air) filtered by the air cleaner into the throttle body of the electronic throttle device via the air cleaner hose (air hose). The intake duct has an air cleaner case, an air cleaner hose, a throttle body, a surge tank, an intake manifold, and the like.

The engine body is composed of a cylinder head, a cylinder block, and the like. An intake port (intake port) formed on one side of the cylinder head is opened and closed by a poppet type intake valve (intake valve), and an exhaust port (exhaust port) formed on the other side of the cylinder head is a poppet. It is opened and closed by a mold exhaust valve (exhaust valve). Furthermore, a spark plug is attached to the cylinder head so that the tip end portion is exposed in the combustion chamber of each cylinder of the engine. The cylinder head is provided with an injector (electromagnetic fuel injection valve) that injects fuel into the intake port at an optimal timing.
A piston coupled to the crankshaft via a connecting rod is supported in a cylinder bore formed inside the cylinder block so as to be slidable in the sliding direction.

The air cleaner is installed in the uppermost stream portion of the intake duct of the engine and houses a filter element (filter element) that captures and removes impurities (dust such as dust, dust, and sand) contained in the outside air.
The air cleaner hose is an intake pipe that connects the air cleaner and the throttle body. The air cleaner hose is formed of a flexible rubber-based elastic body (or a resin material such as a synthetic resin having flexibility). The air cleaner hose is airtightly coupled to the upper end of the throttle body in the intake flow direction.

  The electronic throttle device according to the present embodiment includes a throttle body that is airtightly coupled to the middle of an intake duct of an engine, particularly to a downstream end of an air cleaner hose, and an interior of a throttle bore wall (hereinafter referred to as a cylindrical portion) 1 of the throttle body. A throttle valve (butterfly valve) for opening and closing the (throttle bore 11), an actuator (valve driving device) including a motor for driving the butterfly valve, and a power supplied to the motor coil in accordance with the operating state of the engine. In addition, an engine control unit (hereinafter referred to as ECU) that controls a throttle opening corresponding to the valve angle of the butterfly valve in association with each system such as an ignition device and a fuel injection device is provided.

The electronic throttle device drives the motor according to the accelerator operation amount of the driver to change the throttle opening, and the flow rate of intake air (intake air amount, intake air amount) supplied to the combustion chamber of each cylinder of the engine ) Is variably controlled to control the engine rotation speed or the engine output shaft torque. The accelerator operation amount corresponds to the amount by which the driver depresses the accelerator pedal.
In addition to the throttle body and the butterfly valve, the electronic throttle device includes a return spring that urges the butterfly valve in the valve closing operation direction (the direction in which the valve returns to the fully closed direction). In this embodiment, a coil spring is used as the return spring.

The throttle body of the present embodiment has a cylindrical portion (duct) 1 having a cylindrical shape in which a throttle bore 11 having a circular cross section is formed. The throttle body is formed in a predetermined shape from a resin material or a metal material. The cylindrical portion 1 of the throttle body is a housing that holds the butterfly valve in the rotation direction from the fully closed position to the fully open position, and is tightened to the surge tank (or intake manifold) with bolts or the like. It is fixed.
In this embodiment, the intake air filtered by the air cleaner flows into the throttle bore 11 from the inlet portion opened at the upper end portion of the cylindrical portion 1 of the throttle body and is shown at the lower end portion of the cylindrical portion 1 of the throttle body. It is configured to be sucked into an intake port and a combustion chamber of each cylinder of the engine through a surge tank connected to an outlet portion opened at, and an intake manifold.

The cylindrical part 1 accommodates a butterfly valve in an openable and closable manner. The cylindrical portion 1 has a throttle bore (air flow path, intake passage) 11. Thus, the cylindrical portion 1 constitutes an intake air introduction duct (housing) for introducing intake air into the combustion chamber for each cylinder of the engine. The throttle bore 11 extends straight from the inlet side opening end of the cylindrical portion 1 toward the outlet side opening end.
A sensor cover 12 that holds and fixes a throttle opening sensor that detects the throttle opening is attached to the end of the cylindrical portion 1 in the rotation axis direction (the right end in the drawing in FIG. 1). A motor housing 13 that houses a motor is integrally formed in the throttle body or the outer wall portion of the cylindrical portion 1.

In addition, the cylindrical portion 1 is provided with a pair (two) of first and second shaft bearing portions 14 and 15 that are disposed to face each other with a throttle bore 11 therebetween. Inside these first and second shaft bearing portions 14 and 15, shaft housing holes having a circular cross section extending in the rotation axis direction of the butterfly valve are provided.
A first bearing (sliding bearing) 16 that pivotally supports one end portion (first projecting portion 21) in the rotation axis direction of the shaft 2 is provided on the inner periphery (accommodating hole wall surface) of the shaft accommodating hole of the first shaft bearing portion 14. Mated and held. That is, the first shaft bearing portion 14 supports the one end portion (first projecting portion 21) in the rotation axis direction of the shaft 2 slidably in the rotation direction via the first bearing 16. Further, a second bearing (sliding bearing) that pivotally supports the other end portion (second projecting portion 22) in the rotation axis direction of the shaft 2 is provided on the inner periphery (accommodating hole wall surface) of the shaft accommodating hole of the second shaft bearing portion 15. 17 is fitted and held. That is, the second shaft bearing portion 15 supports the other end portion (second projecting portion 22) in the rotation axis direction of the shaft 2 via the second bearing 17 so as to be slidable in the rotation direction.
Here, a sliding bearing is used as the first bearing 16, and a sliding bearing (or a rolling bearing or a ball bearing) is used as the second bearing 17.

  The butterfly valve of the present embodiment is installed in the throttle bore 11 communicating with the combustion chambers and intake ports of all cylinders of the engine so as to be freely opened and closed. This butterfly valve is housed in a throttle body cylindrical portion 1 (throttle bore 11) so as to be openable and closable, and is a rotary intake control valve that rotates relative to the cylindrical portion 1 of the throttle body, that is, the center of the shaft 2. This is a disk-like throttle valve that rotates around an axis to open and close the throttle bore 11. The butterfly valve rotates in the valve operating range from the fully closed position to the fully open position (changes the rotation angle) based on a control signal from the ECU during engine operation, thereby opening the opening area of the throttle bore 11. By changing the (intake air flow area), the flow rate of the intake air is variably controlled.

Further, when the power supply to the motor is stopped when the engine is stopped, the butterfly valve is in a fully closed position (or an intermediate opening state slightly opened from the fully closed position (intermediate position) by an urging force such as a return spring, for example. )).
The butterfly valve includes a metal shaft 2 rotatably supported by shaft bearing portions 14 and 15 provided in the cylindrical portion 1 of the throttle body, and a disc-shaped valve body 3 supported by the shaft 2. Have.
When the butterfly valve is set to the fully closed position, both the front and back sides of the valve body 3 are opened with respect to a vertical line perpendicular to the flow path direction of the cylindrical portion 1 of the throttle body (the axial direction of the throttle bore 11). The valve is arranged so as to be slightly inclined by a predetermined rotation angle in the valve operating direction.
Here, the butterfly valve of the present embodiment is a resin mold valve in which a cylindrical shaft 2 formed of metal is insert-molded in a state in which both end portions in the rotation axis direction protrude.
The details of the butterfly valve, particularly the shaft 2 and the valve body 3 will be described later.

  Here, the actuator that drives the shaft 2 of the butterfly valve in the valve opening operation direction or the valve closing operation direction is a motor that generates a driving force when supplied with electric power, and the rotational motion of the output shaft of the motor to the shaft 2. It is an electric actuator configured to include a power transmission mechanism for transmitting. The power transmission mechanism is constituted by a gear reduction mechanism that reduces the rotation speed of the motor to a predetermined reduction ratio and increases the driving force (motor torque) of the motor. This gear reduction mechanism has a pinion gear (motor gear) fixed to the output shaft of the motor, an intermediate reduction gear that rotates in mesh with the motor gear, and a final reduction gear that rotates in engagement with the intermediate reduction gear. Note that the output shaft of the motor may be directly connected to the shaft 2.

The motor is electrically connected to a battery mounted on the automobile via a motor drive circuit electronically controlled by the ECU. This motor is built in a motor housing 13 formed integrally with the throttle body.
Here, for example, when electric power is supplied to the coil of the rotor, the motor that generates the driving force for driving the shaft 2 of the butterfly valve is configured to be energized (driven) by the ECU. The ECU includes a CPU for performing control processing and arithmetic processing, a storage device (memory such as ROM and RAM) for storing a control program or control logic and various data, an input circuit (input unit), an output circuit (output unit), A microcomputer having a known structure configured to include functions such as a power supply circuit and a timer is provided.

Then, when an ignition switch (not shown) is turned on (IG / ON), the ECU drives the shaft 2 of the butterfly valve of the electronic throttle device based on a control program or control logic stored in the memory of the microcomputer. The motor coil is energized and controlled, and the ignition device (ignition coil, spark plug, etc.) and fuel injection device (electric fuel pump, injector, etc.) are driven. Thereby, during the operation of the engine, the throttle opening (intake air flow rate), the fuel injection amount, and the like are controlled so as to become control command values (control target values), respectively.
The ECU includes the throttle opening control, ignition control, fuel injection control, and the like based on a control program or control logic stored in the memory of the microcomputer when the ignition switch is turned off (IG / OFF). The engine control is forcibly terminated.

Further, a crank angle sensor, an accelerator opening sensor, and a throttle opening sensor are connected to the ECU. In addition, a cooling water temperature sensor, an intake air temperature sensor, an air flow meter, and an intake pressure sensor are connected to the ECU. Sensor signals from these various sensors are A / D converted by an A / D converter and then input to a microcomputer.
The crank angle sensor, the accelerator opening sensor, the throttle opening sensor, the cooling water temperature sensor, the intake air temperature sensor, the air flow meter, the intake pressure sensor, and the like constitute an operation state detection means for detecting the operation state of the engine. The throttle opening sensor is a non-contact rotation angle detection device that detects the throttle opening, and is a split permanent magnet (magnet) fixed to the inner peripheral side of the final reduction gear. And a non-contact type magnetic detection element that is held and fixed to the sensor mounting portion of the sensor cover 12. As the non-contact type magnetic detection element, any one of a Hall element, a Hall IC, or a magnetoresistive element is used.
Here, the ECU feedback-controls the power supplied to the motor coil so that there is no deviation between the accelerator opening signal output from the accelerator opening sensor and the throttle opening signal output from the throttle opening sensor. Yes.

Next, the details of the butterfly valve of this embodiment, particularly the shaft 2 and the valve body 3, will be described with reference to FIGS.
The butterfly valve has a cross-sectional shape of the valve body 3, that is, a rhombus in which a cross section perpendicular to the axial direction of the axial direction portion 4 gradually decreases in thickness from the axial direction portion 4 toward the outer peripheral end. It is formed in a streamline shape.
The shaft 2 is integrally formed in a cylindrical shape (round bar shape) with a metal such as brass or stainless steel (or an aluminum alloy or a magnesium alloy containing a copper-based metal). The shaft 2 extends straight in the direction of the rotation axis.
The shaft 2 includes a first projecting portion 21 projecting outward from the annular end surface of one end portion (first cylindrical portion) 18 of the valve body 3 in the rotational axis direction, and the other end portion of the valve body 3 in the rotational axis direction. (Second cylindrical portion) Provided between the second projecting portion 22 projecting outward from the annular end surface of the 19 and the two first and second projecting portions 21, 22 and integrally connecting the valve body 3. It has a valve holding part. One of the two first and second protrusions 21 and 22 (for example, the second protrusion 22) is drivingly connected to the output shaft of the motor via a power transmission mechanism.

The 1st protrusion part 21 is inserted in the shaft accommodation hole of the 1st shaft bearing part 14 provided in the one end side of the rotating shaft direction of the shaft 2 of a butterfly valve. A part or the whole of the outer peripheral surface of the first protrusion 21 functions as a first sliding surface that slides freely with respect to the inner periphery of the first sliding hole of the first bearing 16.
The 2nd protrusion part 22 is inserted in the shaft accommodation hole of the 2nd shaft bearing part 15 provided in the other end side of the rotating shaft direction of the shaft 2 of a butterfly valve. A part or the whole of the outer peripheral surface of the second protrusion 22 functions as a second sliding surface that slides rotatably with respect to the inner periphery of the second sliding hole of the second bearing 17.

The valve body 3 is integrally formed of a synthetic resin such as a thermoplastic resin excellent in heat resistance (for example, polyphenylene sulfide: PPS or polybutylene terephthalate: PBT or polyamide resin: PA or polypropylene: PP or polyetherimide: PEI). Has been.
Here, the valve main body 3 has a disk-shaped portion that extends radially on the outer diameter side in the radial direction around the intersection of the central axis in the flow path direction of the cylindrical portion 1 of the throttle body and the central axis of the shaft 2. doing. The flow path direction of the cylindrical portion 1 of the throttle body refers to the vertical direction when the electronic throttle device is mounted on the automobile (the vertical direction of the automobile, the vertical direction in the direction of gravity), and the axial direction of the throttle bore 11 (Vertical direction shown in FIG. 2).

Further, the disc-shaped part of the valve body 3 has an axial part (intermediate outer diameter part) 4 extending in the rotational axis direction (diameter direction). The axial direction portion 4 constitutes a shaft covering portion that covers the valve holding portion of the shaft 2, that is, a resin mold that insert-molds the valve holding portion of the shaft 2.
Maximum outer diameter portions (flange portions) 23 and 24 larger than the outer diameter of the axial direction portion 4 are provided at both ends of the axial direction portion 4 of the valve body 3 in the rotation axis direction. Between the axial direction part 4 and the largest outer diameter parts 23 and 24, it is the inclined surface (taper surface) or conical surface of a predetermined inclination angle.
A first cylindrical portion (minimum outer diameter portion) having a smaller diameter than the axial direction portion 4 and the maximum outer diameter portion 23 from one end surface of the axial direction portion 4 of the valve body 3 in the rotation axis direction, that is, the end surface of the maximum outer diameter portion 23. ) 18 protrudes. Further, from the other end surface in the rotation axis direction of the axial direction portion 4 of the valve body 3, that is, from the end surface of the maximum outer diameter portion 24, the second cylindrical portion (minimum outer diameter) smaller than the axial direction portion 4 and the maximum outer diameter portion 24. (Diameter part) 19 protrudes.

The disk-shaped portion of the valve body 3 has a streamlined cross section perpendicular to the direction orthogonal to the axial direction of the axial portion 4. Further, the disc-shaped portion of the valve body 3 has two semi-disc-shaped portions (upstream and downstream discs, which are arranged stepwise in the thickness direction of the disc-shaped portion with the axial direction portion 4 as a boundary. (Hereinafter referred to as a valve disc of the valve body 3) 5 and 6.
In the present embodiment, when the butterfly valve is fully closed, as shown in FIG. 1, the valve disk 6 is disposed on the lower side in the direction of gravity than the valve disk 5. In the butterfly valve, when the surface of the valve body 3 shown in FIG. 2 is the front side surface of the valve body 3, the opposite side is the back side surface of the valve body 3. Further, in this embodiment, when the butterfly valve is fully opened, as shown in FIG. 2, the valve disk 6 is disposed downstream of the valve disk 5 in the intake flow direction (flow path direction).
Here, on the front and back side surfaces of the valve discs 5 and 6 of the valve body 3, the first and first slanting down in the direction perpendicular to the axial direction of the axial portion 4 from the axial portion 4 toward the outer peripheral end. Two taper surfaces are respectively formed.
The outer peripheral end 25 of the valve disc 3 of the valve body 3 is formed with an outer peripheral end edge 25 that is gently inclined along the outer periphery of the valve disc 5 with a predetermined width (the width on the bearing side is wider than the width on the center side). ing. The outer peripheral edge of the valve disc 6 of the valve body 3 has an outer peripheral edge 26 that is gently inclined along the outer periphery of the valve disc 6 and has a predetermined width (the width on the center side is smaller than the outer peripheral edge 25). The width on the bearing side is narrower than 25, and the width on the bearing side is wider than the width on the center side.

The first taper surface formed on the front side surfaces of the valve discs 5 and 6 of the valve body 3 has a direction orthogonal to the axial direction of the axial direction portion 4 from the axial direction portion 4 toward the outer peripheral edges 25 and 26. A plurality of first slits 31 extending in the (vertical direction) are formed.
The second taper surface formed on the back side surfaces of the valve discs 5 and 6 of the valve body 3 is a direction orthogonal to the axial direction of the axial direction portion 4 from the axial direction portion 4 toward the outer peripheral edges 25 and 26. A plurality of second slits 32 extending in the (vertical direction) are formed.
The first tapered surfaces formed on the front side surface of the valve body 3 are partitioned from each other by a plurality of first slits 31, and a plurality of first tapers provided at predetermined intervals along the axial direction of the axial portion 4. 1 rectification taper surface (or 1st protrusion rib or 1st rectification rib) 41 is constituted. In addition, the second tapered surfaces formed on the back side surface of the valve body 3 are partitioned from each other by a plurality of second slits 32, and a plurality of second tapered surfaces provided at predetermined intervals along the axial direction of the axial direction portion 4. It is comprised by 2 rectification | straightening taper surfaces (or 2nd protrusion rib or 2nd rectification rib) 42 grade | etc.,.

  The plurality of first slits 31 are provided at predetermined intervals along the axial direction of the axial portion 4 on the front side surfaces of the valve disks 5 and 6 of the valve body 3. These first slits 31 are disposed symmetrically about the central axis of the first groove 51 provided in the central portion of the front side surface of the valve disc 5 of the valve main body 3. The valve disk 6 is arranged symmetrically about the longest first rectifying taper surface 41 arranged at the center of the front side surface. The plurality of first slits 31 are provided such that the slit width gradually increases from the axial portion 4 toward the outer peripheral edges 25 and 26. The plurality of first slits 31 are slit wall surfaces (side surfaces) on one side (right side shown in FIG. 6) and slits on the other side (left side shown in FIG. 6) on both sides of the groove bottom surface having a predetermined groove depth. Wall surfaces (side surfaces) are formed.

  The groove bottom surfaces of the plurality of first slits 31 formed in the valve disc 5 of the valve body 3 are descending inclined surfaces (curved surfaces, convex curved surfaces) having a steep inclination angle on the axial direction portion 4 side. Up to the end edge 25 is a downward inclined surface with a gentle inclination angle, and is smoothly connected to the outer peripheral edge 25. Further, the groove bottom surfaces of the plurality of first slits 31 formed on the valve disk 6 of the valve body 3 are descending inclined surfaces (curved surfaces, convex curved surfaces) having a steep inclination angle on the axial direction portion 4 side. Up to the end edge 26 is a downwardly inclined surface with a gentle inclination angle, and is smoothly connected to the outer peripheral edge 26. The steep slope on the valve disc 6 side is gentler and longer than the steep slope on the valve disc 5 side. In other words, the width of the valve disk 6 in the axial direction portion 4 is wider in the vertical direction perpendicular to the axial direction of the axial direction portion 4 on the front side surface of the valve body 3 than in the valve disk 5 side. .

  The plurality of second slits 32 are provided at predetermined intervals along the axial direction of the axial portion 4 on the back side surfaces of the valve disks 5 and 6 of the valve body 3. These second slits 32 are arranged symmetrically about the longest second rectifying taper surface 42 arranged at the center of the back side surface of the valve disc 5 of the valve body 3. These are arranged symmetrically about the central axis of the second groove 52 provided at the center of the back side surface of the valve disk 6. The plurality of second slits 32 are provided such that the slit width gradually increases from the axial portion 4 toward the outer peripheral edges 25 and 26. The plurality of second slits 32 are provided on both sides of the groove bottom surface having a predetermined groove depth, on one side (right side shown in FIG. 6) and on the other side (left side shown in FIG. 6). Wall surfaces (side surfaces) are formed.

  The groove bottom surfaces of the plurality of second slits 32 formed in the valve disk 5 of the valve body 3 are descending inclined surfaces (curved surfaces, convex curved surfaces) having a steep inclination angle on the axial direction portion 4 side. Up to the end edge 25 is a downward inclined surface with a gentle inclination angle, and is smoothly connected to the outer peripheral edge 25. The groove bottom surfaces of the plurality of second slits 32 formed on the valve disk 6 of the valve body 3 are descending inclined surfaces (curved surfaces, convex curved surfaces) having a steep inclination angle on the axial direction portion 4 side. Up to the end edge 26 is a downwardly inclined surface with a gentle inclination angle, and is smoothly connected to the outer peripheral edge 26. The steep slope on the valve disc 5 side is gentler and longer than the steep slope on the valve disc 6 side. That is, the axial direction portion 4 has a width of the valve disc 5 wider in the vertical direction perpendicular to the axial direction of the axial direction portion 4 on the back side surface of the valve body 3 than the width on the valve disc 6 side. .

  The plurality of first rectifying taper surfaces 41 are inclined surfaces inclined downward at a predetermined inclination angle (taper angle) from the axial direction portion 4 toward the outer peripheral edges 25 and 26 and smoothly connected to the outer peripheral edges 25 and 26. ing. These first rectifying taper surfaces 41 may be the first protrusion ribs or the top surfaces of the first rectification ribs that protrude from the groove bottom surfaces of the plurality of first slits 31 to one side (front side surface) in the plate thickness direction. The plurality of second rectifying tapered surfaces 42 are inclined surfaces inclined downward at a predetermined inclination angle (taper angle) from the axial direction portion 4 toward the outer peripheral edges 25 and 26, and are smoothly connected to the outer peripheral edges 25 and 26. ing. These second rectifying taper surfaces 42 may be the second protrusion ribs or the top surfaces of the second rectification ribs protruding from the groove bottom surfaces of the plurality of second slits 32 to the other side (back side surface) in the plate thickness direction.

A first groove 51 is formed in the central portion of the front side surface of the valve disc 5 of the valve body 3 and extends straight in the direction orthogonal to the axial direction of the axial portion 4 through the center of the valve disc 5. ing. Further, a second groove 52 is formed in the central portion of the back side surface of the valve disc 6 of the valve body 3 and extends straight in the direction perpendicular to the axial direction of the axial direction portion 4 through the center of the valve disc 6. ing.
Here, in the butterfly valve of this embodiment, the position of the first slit 31 is closer to one side in the axial direction of the axial portion 4 than the position of the second slit 32 (one side: the right side shown in FIGS. 5 and 6). Is offset. That is, the center line in the slit width direction of the first slit 31 is closer to one side (the right side in FIG. 5 and FIG. 6) in the axial direction of the axial portion 4 than the center line in the slit width direction of the second slit 32. Offset placement.

Further, as shown in FIG. 6, the butterfly valve has a distance (dimension in the plate thickness direction) between the first rectifying taper surface 41 and the second rectification taper surface 42, and the slits of the adjacent first slits 31. The distance between the slit wall surface on one side in the width direction and the slit wall surface on the other side in the slit width direction of the second slit 32 (rotation axis direction, axial direction of the axial portion 4, direction perpendicular to the plate thickness direction) Is set (designed) so as to satisfy the relationship of a> b. That is, the distance (b) between the slit wall surface on one side in the slit width direction of the adjacent first slit 31 and the slit wall surface on the other side in the slit width direction of the second slit 32 is the adjacent first rectifying taper surface. When the distance between 41 and the second rectifying taper surface 42 is a, it is set (designed) so as to satisfy the relationship of a> b. In addition, since the thickness of the axial direction part 4 of the valve body 3 made of synthetic resin, that is, the resin thickness in the vicinity of the shaft is greatly reduced as compared with that set in the relationship of a ≦ b, the valve body 3 The amount of voids generated in the thick part (inside the synthetic resin) can be further reduced.
The slit width (d) of the first and second slits 31 and 32 is set so as to satisfy the relationship of c> d, where c is the surface width of the first and second rectifying taper surfaces 41 and 42. (Designed) That is, each slit width (d) of the plurality of first slits 31 is narrower than each taper surface width (c) of the plurality of first rectifying tapered surfaces 41. Each slit width (d) of the plurality of second slits 32 is narrower than each taper surface width (c) of the plurality of second rectifying tapered surfaces 42. In addition, since the effect of reducing the thickness of the axial portion 4 of the synthetic resin valve body 3, that is, the resin thickness in the vicinity of the shaft is greater than that set in the relationship of c ≦ d, the valve body 3 The amount of voids generated in the thick part (inside the synthetic resin) can be further reduced.

[Operation of Example 1]
Next, the operation of the intake device (electronic throttle device) of the internal combustion engine of this embodiment will be briefly described with reference to FIGS.

When the engine key switch is turned on, that is, when the ignition switch is turned on (IG / ON), the ECU controls the energization of the motor of the electronic throttle device (butterfly valve, etc.), and also the ignition device (ignition coil, spark plug, etc.) A fuel injection device (electric fuel pump, injector, etc.) is driven. As a result, the engine is operated.
Here, when the driver depresses the accelerator pedal, the accelerator opening signal output from the accelerator opening sensor is input to the ECU. Then, electric power is supplied to the motor so that the butterfly valve has a predetermined throttle opening (rotation angle) by the ECU, and the output shaft of the motor rotates. As a result, the shaft 2 that is drivingly connected to the output shaft of the motor rotates by the rotation angle corresponding to the depression amount (accelerator operation amount) of the accelerator pedal against the urging force of the return spring.

Therefore, the butterfly valve held by the shaft 2 is driven in a direction (a valve opening operation direction) that opens from the fully closed position to the fully opened position.
When a specific cylinder of the engine moves from an exhaust stroke to an intake stroke in which the intake valve opens and the piston descends, the negative pressure (pressure lower than atmospheric pressure) in the combustion chamber of the cylinder increases as the piston descends. The air-fuel mixture is sucked from the intake port that is open. At this time, since the throttle bore 11 of the throttle body is opened by a predetermined valve angle (throttle opening of the electronic throttle device) in the middle of the intake duct, the engine speed corresponds to the amount of depression of the accelerator pedal (accelerator operation amount). The speed is changed.

[Effect of Example 1]
As described above, the butterfly valve used as the throttle valve of the electronic throttle device of the internal combustion engine of the present embodiment is rotatable on the first and second shaft bearing portions 14 and 15 provided in the cylindrical portion 1 of the throttle body. A metal shaft 2 to be supported and a synthetic resin valve body 3 supported by the shaft 2 are configured. This butterfly valve is a resin molded valve in which a metal shaft 2 is insert-molded (covered) at the center of an axial portion 4 of a valve body 3 made of synthetic resin.

In the butterfly valve, a cross section perpendicular to the direction perpendicular to the axial direction of the axial portion 4 of the valve body 3 (perpendicular to the rotational axis direction) is formed in a streamline shape such as a rhombus. . That is, the cross-sectional shape of the valve body 3 is a cross-sectional shape with a low resistance to the flow of intake air supplied to the combustion chamber for each cylinder of the engine.
Thus, when the butterfly valve is fully opened in the cylindrical portion 1 of the throttle body, the flow of the intake air on both the front and back sides of the valve body 3 is parallel to the throttle bore 11, and the axis of the valve body 3 of the butterfly valve The direction portion 4 does not disturb the intake air. As a result, the pressure loss when the butterfly valve is fully opened can be reduced, so that the air flow rate when the butterfly valve is fully opened, that is, the fully open flow rate can be increased.

  A plurality of first and second surfaces extending in a direction orthogonal to the axial direction of the axial direction portion 4 from the axial direction portion 4 toward the outer peripheral ends 25 and 26 on both front and back side surfaces of the valve discs 5 and 6 of the valve main body 3. Second slits 31 and 32 are formed. In the butterfly valve of this embodiment, the position of the first slit 31 is offset from the position of the second slit 32 closer to one side in the axial direction of the axial portion 4 (one side: the right side shown in FIGS. 5 and 6). doing. That is, the center line in the slit width direction of the first slit 31 is closer to one side (the right side in FIG. 5 and FIG. 6) in the axial direction of the axial portion 4 than the center line in the slit width direction of the second slit 32. Offset placement. That is, the center of the slit width of the first slit 31 is not formed at the opposite position (axisymmetric with respect to the shaft 2) on the front and back side surfaces of the valve disks 5 and 6 of the valve body 3.

  As a result, when the center position of the taper surface (slit) 106 formed on the front side surface of the valve body 101 and the center position of the taper surface (slit) 106 formed on the back side surface of the valve body 101 are arranged to face each other ( The inside diameter of the synthetic resin valve body 3, that is, the inscribed circle inside the resin is smaller than that of the synthetic resin valve body 3 (see FIG. 7B). Specifically, even when the plate thicknesses of the valve bodies 3 and 101 are the same and the distance between the slit groove bottom surfaces of the front and back sides of the valve bodies 3 and 101 is the same, both sides of the valve body 101 are front and back. The diameter of the inscribed circle inside the resin in contact with each edge of the slit 106 is φ3.6, whereas the first and second surfaces formed on both front and back sides of the valve discs 5 and 6 of the valve body 3 are as follows. The diameter of the inscribed circle inside the resin in contact with each edge of the slits 31 and 32 is φ3.1, and compared with the conventional examples 1 and 2 shown in FIG. 7A, the inside of the valve body 3 made of synthetic resin, that is, the resin It can be seen that the inner inscribed circle diameter becomes smaller.

  Therefore, in the butterfly valve used as the throttle valve of the electronic throttle device of the internal combustion engine of this embodiment, the thickness of the axial portion 4 of the valve body 3 made of synthetic resin, that is, the resin thickness in the vicinity of the shaft 2 is thin. Thus, the amount of voids generated in the synthetic resin can be reduced. As a result, the axial direction portion of the valve body 3 made of synthetic resin is maintained while maintaining a streamline shape with a low resistance to the flow of intake air supplied to the combustion chamber for each cylinder of the engine as the cross-sectional shape of the valve body 3. By reducing the thickness of the resin 4, that is, the thickness of the resin in the vicinity of the shaft 2, the strength of the valve body 3 made of synthetic resin can be secured and the resin moldability and quality can be improved without impairing the fully opened flow rate performance. it can.

[Modification]
In this embodiment, the valve of the present invention is applied to a butterfly valve that controls the amount of intake air supplied to the combustion chamber of the internal combustion engine (engine). The present invention may be applied to an intake air flow control valve that generates an intake air vortex for promoting combustion. The valve of the present invention may be applied to a valve body of an intake passage opening / closing device that opens and closes an intake passage of an internal combustion engine (engine).
In the present embodiment, the actuator that drives the shaft 2 of the butterfly valve is constituted by an electric actuator provided with a motor and a power transmission mechanism. However, the actuator that drives the shaft of the valve may be an electromagnetic or electric negative pressure. You may comprise by the negative-pressure actuated actuator provided with the control valve.

Further, the intake device for an internal combustion engine of the present invention may be applied to a throttle device for operating the butterfly valve by mechanically transmitting the depression amount of the accelerator pedal to the butterfly valve shaft 2 via a wire.
A diesel engine may be used as the engine. Further, as the engine, not only a multi-cylinder engine but also a single-cylinder engine may be used.
In this embodiment, an air cleaner hose (air hose) is connected between the air cleaner case and the throttle body, but an intake duct may be connected between the air cleaner case and the throttle body.

1 is a plan view showing an electronic throttle device for an internal combustion engine (Example 1). FIG. 1 is a cross-sectional view showing an electronic throttle device for an internal combustion engine (Example 1). It is the perspective view which showed the butterfly valve made from a synthetic resin (Example 1). It is the top view which showed the butterfly valve made from a synthetic resin (Example 1). (A) is the side view which looked at the butterfly valve made from a synthetic resin from the lower side of Drawing 4, and (b) is an AA sectional view of Drawing 4 (Example 1). It is sectional drawing which showed the principal part of the synthetic resin butterfly valve (Example 1). (A) is sectional drawing which showed the synthetic resin butterfly valve (conventional example 1 and 2). (B) is sectional drawing which showed the principal part of the synthetic resin butterfly valve (Example 1). It is sectional drawing which showed the intake device of the internal combustion engine (conventional example 1). (A) is the side view which looked at the butterfly valve from the left side of FIG. 8, (b) is BB sectional drawing of FIG. 8, (c) is CC sectional drawing of FIG. ). It is sectional drawing which showed the intake device of the internal combustion engine (conventional example 2). (A) is the side view which looked at the butterfly valve from the left side of FIG. 10, (b) is DD sectional drawing of FIG. 10, (c) is EE sectional drawing of FIG. ).

Explanation of symbols

1 Cylindrical part of the throttle body (duct, throttle bore wall)
2 Shaft of butterfly valve (resin mold valve) 3 Valve body of butterfly valve (resin mold valve) 4 Axial part of valve body (resin mold)
5 Valve disc of valve body (semi-circular plate, plate valve)
6 Valve disc of valve body (semi-circular plate, plate valve)
11 Throttle bore (air passage, intake passage)
DESCRIPTION OF SYMBOLS 21 1st protrusion part of shaft 22 2nd protrusion part of shaft 25 Outer peripheral edge of valve disc of valve body 26 Outer peripheral edge of valve disc of valve body 31 First slit of valve disc of valve body 32 Valve disc of valve body The second slit 41 of the valve body The first straightening taper surface of the valve disc of the valve body 42 The second straightening taper surface of the valve disc of the valve body

Claims (7)

(A) a duct forming an air flow path communicating with the combustion chamber of the internal combustion engine;
(B) In an intake device for an internal combustion engine including a butterfly valve housed in the duct and opening and closing the air flow path,
The butterfly valve has a metal shaft rotatably supported by the duct, and a resin valve body supported by the shaft,
The valve body has an axial portion extending in the rotational axis direction, and a cross section perpendicular to the axial direction of the axial direction portion is formed in a streamline shape,
A first slit extending in a direction orthogonal to the axial direction of the axial portion from the axial portion toward the outer peripheral end is formed on the front side surface of the valve body,
A second slit extending in a direction orthogonal to the axial direction of the axial portion from the axial portion toward the outer peripheral end is formed on the back side surface of the valve body,
The center line of the slit width direction of the first slit, an intake system for an internal combustion engine, characterized by being arranged offset relative to the center line of the slit width direction of the second slit. The intake device for an internal combustion engine according to claim 1,
The center line of the slit width direction of the first slit, the internal combustion engine, characterized by being arranged offset to one side toward the axial direction of the axial portion with respect to the slit width direction of the center line of the second slit Inhalation device. The intake device for an internal combustion engine according to claim 1 or 2,
The intake device for an internal combustion engine, wherein the butterfly valve is a resin molded valve that covers the shaft in the axial direction portion. The intake device for an internal combustion engine according to any one of claims 1 to 3, wherein a first tapered surface inclined downward from the axial direction portion toward an outer peripheral end is provided on a front side surface of the valve body. Is formed,
An intake device for an internal combustion engine, wherein a second tapered surface inclined downward from the axial direction portion toward the outer peripheral end is formed on the back side surface of the valve body. The intake device for an internal combustion engine according to claim 4,
The first slit is composed of a plurality of first slits provided at predetermined intervals along the axial direction of the axial portion,
The second slit is composed of a plurality of second slits provided at predetermined intervals along the axial direction of the axial portion,
The plurality of first slits are formed in the first tapered surface,
An intake device for an internal combustion engine, wherein the second tapered surface is formed with the plurality of second slits. The intake device for an internal combustion engine according to claim 5,
The first taper surface is composed of a plurality of first taper surfaces that are partitioned from each other by the plurality of first slits and provided at predetermined intervals along the axial direction of the axial direction portion,
The second tapered surface is composed of a plurality of second tapered surfaces that are partitioned from each other by the plurality of second slits and provided at predetermined intervals along the axial direction of the axial direction portion,
The slit width of at least one first slit of the plurality of first slits is narrower than the surface width of at least one first tapered surface of the plurality of first tapered surfaces,
An internal combustion engine characterized in that a slit width of at least one second slit of the plurality of second slits is narrower than a surface width of at least one second tapered surface of the plurality of second tapered surfaces. Inhalation device. The intake device for an internal combustion engine according to any one of claims 4 to 6, wherein a distance between the first tapered surface and the second tapered surface is a,
When the distance between the slit wall surface on one side in the slit width direction of the first slit and the slit wall surface on the other side in the slit width direction of the second slit is b,
a> b
An intake device for an internal combustion engine characterized by satisfying the relationship:

Images