JP2004132182A - Throttle valve drive device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a throttle valve drive device of simple structure at low cost, which can stop water infiltration at an expansion chamber even if a throttle body is soaked in the water, and can easily drain the water collected within the expansion chamber. <P>SOLUTION: In this throttle valve drive device, a throttle valve 3 is disposed in an intake system of an internal combustion engine, and a throttle shaft 4 thereof is journaled to by a throttle body 1 to allow rotation of the throttle valve 3. Driving force of a motor 20 is transmitted to the throttle shaft 4 through a power transmission mechanism 30 to open/close the throttle valve 3. Further, in this throttle valve drive device, the throttle body 1 is provided with a motor housing chamber 7 housing the motor 20 and a transmission mechanism housing chamber 8 housing the power transmission mechanism 30. At a lower part of the throttle body 1, the expansion chamber 10 is disposed to communicate with the motor housing chamber 7 and transmission mechanism housing chamber 8 through communicating holes 18, 19. A drain port 17 is formed in a bottom part of the expansion chamber 10, and a vent hole 15 is disposed to the expansion chamber 10 below the communicating holes 18, 19 and above the drain port 17. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a throttle valve driving device driven by a motor of an internal combustion engine.
[0002]
[Prior art]
A butterfly type throttle valve disposed in an intake system of the internal combustion engine is rotatably provided with its throttle shaft supported by a throttle body, and the driving force of a motor is transmitted to the throttle shaft via a power transmission mechanism. Conventionally, there is a throttle valve driving device in which a throttle valve is opened and closed.
[0003]
There is an example in which an expansion chamber is provided below a power transmission mechanism (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-3-50347 (pages 6, 7; FIG. 3)
[0005]
The above publication describes the following configuration.
That is, a chamber, which is an expansion chamber, is integrally formed below a gear box that houses a gear train, which is a power transmission mechanism. A drain is formed.
In addition, a ventilation hole communicating with the atmosphere is provided on the upper wall of the gear box.
[0006]
Water condensed in the gear box and the motor chamber can be drained from the drain through the drain hole, and direct ingress of water from the outside is prevented by the chamber.
Further, since the volumes of the gear box and the motor housing chamber are expanded by the chamber, the chamber can prevent the water from being sucked into the gear box at the same time when the inside of the gear box or the like is cooled and the outside air is sucked.
[0007]
[Problems to be solved by the invention]
However, since the ventilation hole is provided in the upper wall of the gear box, the opening of the ventilation hole is opened to the atmosphere through a filter such as an air cleaner in order to prevent water from entering the ventilation hole. In this case, a pipe is required from the bottom to the vent hole, which is disadvantageous in terms of cost and man-hour for assembling.
[0008]
Although the vent facilitates draining of the chamber, when the throttle body is immersed in water, the vent is provided in the upper part of the gear box, and the vent is provided through the drain through the chamber. Therefore, water easily penetrates into the gear box to a height corresponding to the water surface.
[0009]
Further, since the chamber is formed integrally with the gear box, complicated processing is required.
[0010]
SUMMARY OF THE INVENTION The present invention has been made in view of such a point, and an object of the present invention is to prevent water from entering the expansion chamber even if the throttle body is immersed in water, and to discharge water accumulated in the expansion chamber. Another object of the present invention is to provide an inexpensive throttle valve driving device having a simple structure.
[0011]
Means for Solving the Problems and Functions and Effects
In order to achieve the above object, according to the present invention, a throttle valve provided in an intake system of an internal combustion engine is rotatably provided with its throttle shaft supported by a throttle body, and is provided with a throttle valve. In a throttle valve driving device in which a driving force is transmitted to the throttle shaft via a power transmission mechanism to open and close the throttle valve, a motor housing chamber for housing the motor in the throttle body and the power transmission mechanism are provided. A transmission mechanism accommodating chamber for accommodating the motor is provided, and an extension chamber communicating with the motor accommodation chamber and the transmission mechanism accommodating chamber through a communication hole is provided below the throttle body, and a drain port is formed at a bottom of the extension chamber. A throttle valve driving device for an internal combustion engine, wherein the expansion chamber is provided with a vent hole communicating with the atmosphere below the communication hole and above the drain port. .
[0012]
Since the ventilation hole communicating with the atmosphere is located below the communication hole and above the drain port, even if the throttle body is immersed in water, it is possible to take in the air of the capacity of the expansion chamber, and If the vent holes are blocked by the intruded water, the infiltration of water can be suppressed up to the expansion chamber.
[0013]
Further, drainage of water accumulated in the expansion chamber is easily performed by the ventilation hole.
Further, since the ventilation hole is provided in the expansion chamber provided below the throttle body, water does not directly enter from the ventilation hole without special piping, which is advantageous in terms of cost and assembly man-hour.
[0014]
Note that water condensed in the transmission mechanism housing chamber and the motor housing chamber can be discharged from the drain port through the communication hole, and direct ingress of water from the outside is prevented by the expansion chamber.
Furthermore, since the capacity of the transmission mechanism housing chamber and the motor housing chamber is expanded by the chamber, it is necessary to secure intake air through the communication hole even when the inside of the transmission mechanism housing chamber or the like cools down and the internal pressure drops when wet. In such a case, even if water is sucked in at the same time when the outside air is sucked, it is possible to prevent water from penetrating into the transmission mechanism accommodating chamber or the like up to the expansion chamber.
[0015]
According to a second aspect of the present invention, in the throttle valve driving device for an internal combustion engine according to the first aspect, the vent hole is formed of a cylindrical wall formed by inwardly expanding a part of a bottom wall of the expansion chamber. It is characterized in that it is formed at the tip.
[0016]
When the throttle body is immersed in water, the drain port at the bottom of the expansion chamber and the lower end opening of the recess formed by the cylindrical wall are almost simultaneously immersed in water and closed, so that the vent hole at the tip end is a vent hole. Thus, it is possible to prevent water from entering the expansion chamber up to the water surface.
[0017]
According to a third aspect of the present invention, in the throttle valve driving device for an internal combustion engine according to the second aspect, the cylinder wall bulges upward from a bottom wall of the expansion chamber and communicates with the atmosphere formed by the cylinder wall. It is characterized in that the space forms a conical recess having a conical shape whose diameter decreases as it goes upward.
[0018]
Since the concave portion formed by the cylindrical wall has a conical shape in which the diameter decreases as it goes upward, water that has entered the conical concave portion is quickly discharged.
[0019]
According to a fourth aspect of the present invention, in the throttle valve driving device for an internal combustion engine according to the second or third aspect, the vent hole is formed from an upper wall to a side wall of the cylindrical wall.
[0020]
Since the ventilation hole is formed to be bent from the upper wall to the side wall of the cylindrical wall, generation of a water film due to surface tension can be prevented, so that prompt drainage can be promoted.
[0021]
According to a fifth aspect of the present invention, in the throttle valve driving device for an internal combustion engine according to the first aspect, the drain port is formed on a side wall of a concave wall in which a part of a bottom wall of the expansion chamber is bulged slightly inward. It is characterized by being performed.
[0022]
Since the drainage hole is formed as a vertical hole in the side wall of the concave wall, the generation of a water film due to surface tension can be prevented, so that the drainage is not hindered.
[0023]
According to a sixth aspect of the present invention, in the throttle valve driving device for an internal combustion engine according to any one of the first to fifth aspects, the expansion chamber includes a box body separate from the throttle body. It is characterized by being attached to a body.
[0024]
The expansion chamber is constructed by attaching a box separate from the throttle body to the throttle body, so that complicated processing is not required during manufacturing and costs can be reduced, and the throttle body is shared and only the expansion chamber is used. Can be modified to suit various internal combustion engines and vehicle mounting positions.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. The internal combustion engine and the throttle body 1 according to the present embodiment are mounted in an engine room of a vehicle.
[0026]
A front view, a left side view, a partially omitted rear view, and a bottom view of the throttle body 1 in the posture in which the vehicle is mounted are shown in FIGS. 1, 2, 3 and 4, respectively.
FIG. 5 is a sectional view taken along line VV in FIG.
[0027]
A butterfly type throttle valve 3 is provided in a main bore 2 of the throttle body 1 so as to be rotatable with a throttle shaft 4 via a bearing 5 integrally with the throttle shaft 4.
[0028]
The main bore 2 has a left-right direction as an intake direction, and a throttle shaft 4 is axially supported in a front-rear direction.
Below the main bore 2, the throttle body 1 has a hot water passage 6 (a lower opening is closed by a plug 6a having a communication pipe) formed on the front side, and a motor housing chamber 7 formed on the rear side. I have.
[0029]
The rear side of the throttle body 1 is covered with a gear cover 9 from behind to form a gear chamber 8.
A box-shaped expansion case 11 is attached to the throttle body 1 below the motor housing chamber 7 to form an expansion chamber 10 therein.
[0030]
The motor housing chamber 7 formed below the throttle body 1 has a long cylindrical shape in the front-rear direction, and is open to a rear gear chamber 8. A motor 20 is inserted through this opening to allow the motor 20 to be inserted. The flange 21 attached to the rear end is fixed to the opening peripheral portion 7a of the throttle body 1 by a bolt 22 (see FIG. 3).
[0031]
A drive shaft 20a protruding rearward of the motor 20 extends through the flange 21 into the gear chamber 8, and a small-diameter drive gear 31 is fitted to a distal end thereof.
On the other hand, the throttle shaft 4, which is integrally formed with the throttle valve 3 and extends in the front-rear direction, penetrates the seal member 23 and extends rearward to reach the gear chamber 8. In addition to urging in the closing direction, a default spring 25 is interposed to urge the throttle valve 3 in the opening direction.
[0032]
The default spring 25 keeps the throttle valve 3 slightly opened (about 7 degrees) when the driving of the motor 20 is stopped, and enables the limp-home running when a failure occurs.
[0033]
A large-diameter driven gear 35 with missing teeth is fitted to the rear end of the throttle shaft 4 that reaches the gear chamber 8.
An intermediate shaft 32 is provided between the drive gear 31 and the driven gear 35 in the gear chamber 8 and spans the throttle body 1 and the gear cover 9. A large-diameter intermediate gear 33 and a small-diameter intermediate gear 34 are integrally formed on the intermediate shaft 32. The large-diameter intermediate gear 33 meshes with the drive gear 31 and the small-diameter intermediate gear 34 meshes with the driven gear 35 to form the reduction gear mechanism 30 that is a power transmission mechanism.
[0034]
That is, the rotation of the drive gear 31 driven by the motor 20 is transmitted to the throttle shaft 4 via the reduction gear mechanism 30, and the throttle valve 3 is opened against the return spring 23.
[0035]
A gasket 9a is inserted into the mating surface of the gear cover 9 corresponding to the mating surface 1b (see FIG. 3) of the rectangular frame 1a surrounding the gear chamber 8 on the rear surface of the throttle body 1, and the gear cover 9 is mounted on the rear surface of the throttle body 1. Then, the mating surface is sealed by the gasket 9a, and the gear chamber 8 in which the internal reduction gear mechanism 30 is housed is substantially watertightly sealed (see FIG. 5).
[0036]
On the lower surface of the throttle body 1, that is, the lower surface of the motor housing 7, a rectangular frame 1 c surrounding the expansion chamber 10 extends downward, and an upper wall 1 d in the rectangular frame 1 c is formed of the motor housing 7 having an axis in the front-rear direction. As shown in FIG. 6, the right side (the left side in FIG. 6) is deeply recessed and forms an upper space of the expansion chamber 10.
[0037]
On the other hand, the expansion case 11 constituting the center and lower space of the expansion chamber 10 is formed in a box shape by a rectangular side wall 12 and a bottom wall 13 corresponding to the rectangular frame 1c on the throttle body 1 side. An annular groove 12b is formed (see FIG. 8), a gasket 12c is fitted into the annular groove 12b, and the mating surface 12a of the side wall 12 is overlapped with the mating surface of the rectangular frame 1c on the throttle body 1 side with the gasket 12c interposed. At the same time, the expansion chamber 10 is substantially watertightly sealed, and the four corners are screwed with bolts 11a to attach the expansion case 11.
[0038]
On the bottom wall 13 of the extension case 11, a portion offset to the left from the center bulges inward in a conical shape to form a conical cylinder wall 14. The conical cylinder wall 14 communicates with the atmosphere formed therein. The concave portion 14a has a conical shape whose diameter decreases as it goes upward.
The diameter of the upper end of the conical recess 14a is about 7 mm, and the diameter of the lower end opening is about 10 mm.
[0039]
The conical cylinder wall 14 bulges from the bottom wall 13 and its tip reaches the same plane as the mating surface 12a of the side wall 12, as shown in FIG. A pore 15 is formed to communicate the expansion chamber 10 with the atmosphere.
[0040]
As shown in FIG. 9, a concave wall 16 bulging inward in a rectangular shape is formed on the bottom wall 13 at one corner near the conical cylinder wall 14 separately from the conical cylinder wall 14.
The concave wall 16 bulges to a depth of about half of the conical cylindrical wall 14, and a part of the rectangular side wall is missing, and a drain hole 17 is formed as a vertical hole of about 2.5 mm × 12 mm. Have been.
[0041]
The concave portion 16a formed by the concave wall 16 is also widened as the opening portion goes downward, and the vertically long drain port 17 reaches the lowermost portion of the expansion case 11, and communicates the expansion chamber 10 with the atmosphere.
The extension case 11 is attached to the lower surface of the throttle body 1 to form the extension chamber 10 therein.
[0042]
As shown in FIGS. 6 and 7, a first communication hole 18 having a diameter of about 3 mm is formed in the upper wall 1d in the rectangular frame 1c of the expansion chamber 10 as shown in FIGS.
As shown in FIGS. 3 and 6, a second communication hole 19 having a diameter of about 3 mm is also formed in a wall that partitions the expansion chamber 10 facing the concave space on the right side of the upper space of the expansion case 11 from the gear chamber 8. Have been.
[0043]
That is, the expansion chamber 10 communicates with the motor accommodation chamber 7 through the first communication hole 18 and also communicates with the gear chamber 8 through the second communication hole 19 to increase the volume of the motor accommodation chamber 7 and the gear chamber 8. Is expanding.
[0044]
In an expansion chamber 10 provided below the throttle body 1 mounted in the engine room of the vehicle, a ventilation hole 15 communicating with the atmosphere above a conical cylindrical wall 14 bulging upward from a bottom wall 13 of the expansion case 11 is It is located below the first and second communication holes 18 and 19 and above the drain hole 17.
[0045]
Normally, water condensed in the motor chamber 7 and the gear chamber 8 enters the expansion chamber 10 through the first and second communication holes 18 and 19 and is discharged through the drain hole 17.
Since the vent hole 15 and the drain port 17 of the expansion chamber 10 have an opening communicating with the atmosphere in the bottom wall 13 of the expansion case 11, water or the like does not normally enter directly.
[0046]
Even if the motor housing chamber 7 or the gear chamber 8 cools down and the internal pressure decreases when the internal pressure drops, the intake air can be secured through the first and second communication holes 18 and 19, and external air is sucked at that time. Even if water is sucked in at the same time, it is possible to prevent water from penetrating to the motor accommodating chamber 7 and the gear chamber 8 up to the extension chamber 10.
[0047]
In the case where the throttle body 1 is immersed in water, if the water surface S reaches the center of the throttle body 1 as shown in FIG. As it penetrates, it penetrates into the conical recess 14a of the conical cylindrical wall 14 and closes the opening of the conical recess 14a.
[0048]
As the inside of the expansion chamber 10 is sealed with the motor accommodating chamber 7 and the gear chamber 8 and air is confined by the blockage of the conical concave portion 14a and the drain hole 17, the expansion chamber 10 is sealed against the external water surface S as shown in FIG. The surface of the water that has entered the inside and the conical recess 14a is maintained at a low position by the pressure of the enclosed air.
[0049]
Therefore, intrusion of water into the motor storage chamber 7 and the gear chamber 8 is prevented, and the first and second communication holes 18 and 19 are maintained in a communication state, so that the suction operation is ensured.
[0050]
In addition, the ventilation hole 15 on the upper part of the conical cylindrical wall 14 bulging upward from the bottom wall 13 of the extension case 11 is also maintained in the communicating state.
Therefore, when the throttle body 1 comes out of the water, the water that has entered the conical concave portion 14a first falls as shown in FIG.
[0051]
Since the diameter of the conical recess 14a increases as it goes downward, water can be quickly drained without retaining water.
[0052]
When the water escapes from the conical recess 14 a, the vent hole 15 allows the expansion chamber 10 to communicate with the atmosphere, and the expansion chamber 10 can be depressurized. Can be discharged.
[0053]
In addition, since the ventilation hole 15 on the upper part of the conical cylinder wall 14 is formed to be bent from the upper wall to the side wall of the conical cylinder wall 14, the generation of a water film due to surface tension can be prevented. It prevents the expansion chamber 10 from being depressurized due to being closed, and promptly drains water.
[0054]
In addition, since the drain port 17 is also formed as a vertical hole in the side wall of the concave wall 16, the generation of a water film due to surface tension can be prevented, so that the drain is not hindered.
[0055]
Since the expansion chamber 10 is configured by attaching an expansion case 11 separate from the throttle body 1 to the throttle body 1, the manufacturing cost of the throttle body 1 can be reduced without requiring complicated processing.
[0056]
Further, the throttle body 1 can be made common and the expansion case 11 alone can be changed to easily adapt to various internal combustion engines and vehicle mounting positions.
[Brief description of the drawings]
FIG. 1 is a front view of a throttle body according to an embodiment of the present invention.
FIG. 2 is a left side view of the same.
FIG. 3 is a rear view in which the same parts are omitted.
FIG. 4 is a bottom view of the same.
FIG. 5 is a sectional view taken along the line VV of FIG. 1;
FIG. 6 is a partial cross-sectional view along the line VI-VI in FIG. 4;
FIG. 7 is a partial cross-sectional view along the line VII-VII in FIG. 4;
FIG. 8 is a top view of the extension case.
9 is a partial cross-sectional view along the line IX-IX in FIG.
FIG. 10 is a sectional view showing a state where the throttle body is immersed in water.
FIG. 11 is a sectional view showing a state immediately after the throttle body comes out of water.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Throttle body, 2 ... Main bore, 3 ... Throttle valve, 4 ... Throttle shaft, 5 ... Bearing, 6 ... Hot water passage, 7 ... Motor accommodation room, 8 ... Gear room, 9 ... Gear cover, 10 ... Expansion room, 11 ... Expansion case, 12 ... side wall, 13 ... bottom wall, 14 ... conical cylinder wall, 15 ... vent hole, 16 ... concave wall, 17 ... drain port, 18 ... first communication hole, 19 ... second communication hole, 20 ... motor , 21 ... flange, 23 ... seal member, 24 ... return spring, 25 ... default spring, 30 ... reduction gear mechanism, 31 ... drive gear, 32 ... intermediate shaft, 33 ... large diameter intermediate gear, 34 ... small diameter intermediate gear, 35 ... the driven gear.

Claims (6)

A throttle valve disposed in an intake system of the internal combustion engine is rotatably provided with its throttle shaft pivotally supported by a throttle body, and a driving force of a motor is transmitted to the throttle shaft via a power transmission mechanism. In a throttle valve drive device in which an opening and closing operation of a throttle valve is performed,
A motor housing chamber for housing the motor in the throttle body and a transmission mechanism housing chamber for housing the power transmission mechanism are provided,
An expansion chamber communicating with the motor housing chamber and the transmission mechanism housing chamber through a communication hole is provided below the throttle body,
A drain port is formed at the bottom of the expansion chamber,
A throttle valve driving device for an internal combustion engine, wherein a ventilation hole communicating with the atmosphere is provided in the expansion chamber below the communication hole and above the drain port. 2. The throttle valve drive for an internal combustion engine according to claim 1, wherein the vent hole is formed at a distal end portion of a cylindrical wall in which a part of a bottom wall of the expansion chamber is inwardly bulged in a cylindrical shape. apparatus. The cylinder wall swells upward from a bottom wall of the expansion chamber,
3. The throttle valve driving device for an internal combustion engine according to claim 2, wherein an inner space formed by the cylindrical wall and communicating with the atmosphere forms a conical concave portion having a conical shape whose diameter decreases as it goes upward. 4. The throttle valve driving device for an internal combustion engine according to claim 2, wherein the ventilation hole is formed from an upper wall to a side wall of the cylinder wall. 2. The throttle valve driving device for an internal combustion engine according to claim 1, wherein the drain port is formed on a side wall of a concave wall which is formed by slightly inwardly expanding a part of a bottom wall of the expansion chamber. The throttle of an internal combustion engine according to any one of claims 1 to 5, wherein the expansion chamber is configured by attaching a box separate from the throttle body to the throttle body. Valve drive.

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