JP2001132495A - Throttle control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the wrong contact between the brush of a throttle sensor and base plate and detect a correct throttle opening by preventing the entering of a slide worn powder between parts and a vibration worn powder between parts by an engine vibration. SOLUTION: The brush 18a of a sensor 22 is fixed to the outer end of a throttle shaft 2 projected from a cover 15 and the sensor 22 is stored in the sensor chamber 24 formed on the outside of the cover 15. As a gear chamber 24 for storing a gear and sensor chamber 24 are isolated through a dust seal 17, the worn powder is not entered in the sensor chamber 24 and as a wrong contact is not generated by piling up between the brash 18a and sensor base plate 19, the detection ability of the sensor is not dropped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle control device for controlling an intake air amount of an internal combustion engine, and more particularly to an improvement in the reliability of a throttle sensor for detecting an opening of a throttle valve.

[0002]

2. Description of the Related Art Conventionally, an ECU (Electronic Control Uni
t) A motor that rotates in accordance with a signal from t) opens and closes a throttle valve fixed to a throttle shaft via a gear (reduction gear mechanism) to control the engine speed. Drive gear fixed to the throttle shaft, a throttle gear fixed to the throttle shaft, an intermediate gear mediating the two gears, a return spring for urging the throttle valve in the closing direction, and a throttle sensor unit for detecting the throttle valve opening ( Hereinafter, it is simply referred to as a “sensor unit”). A throttle control device in which both ends of a throttle shaft protrude outward from a bearing of a throttle body main body, a reduction gear mechanism is connected to one end of the throttle shaft, and a sensor unit is connected to the other end of the throttle shaft is known. (For example, see Japanese Patent Application Laid-Open No. 10-15959).
No. 1).

In the prior art described in Japanese Patent Application Laid-Open No. Hei 10-159591, the reduction gear mechanism is connected to one end of the throttle shaft, and the sensor is connected to the other end. It is necessary to provide a gear case and a sensor case at the other end, and there is a problem that the structure of the throttle body is complicated and the number of parts is increased. Therefore, it is conceivable to improve the prior art described in Japanese Patent Application Laid-Open No. Hei 10-159591 to arrange a reduction gear mechanism, a sensor unit, and the like on one side of the throttle shaft and accommodate the same in one room. (See Japanese Patent Application No. 11-68855 filed by the present applicant). In the present invention, which is not known, in FIGS.
Intermediate gear 22, throttle gear 18, fully closed position adjustment screw 23,
A brush 16 for a throttle sensor, a substrate 17 and the like are surrounded by a cover 32 and housed in the same room.

When the reduction gear mechanism, the sensor section, and the like are housed in one room, sliding wear powder generated between the gears or between the spring and the guide abutting on the spring causes the brush of the sensor section and the substrate (resistor) to move. The contact may accumulate and accumulate, resulting in a contact failure and a failure to detect the correct throttle opening. As a countermeasure, the frictional friction between the parts is achieved by mounting a sensor part consisting of a brush and a substrate near the throttle bore of the throttle shaft and covering it with a cylindrical cover with a lid that is configured to fit into the throttle body body. There is a plan to prevent the ingress of powder,
It is unavoidable that vibration friction powder due to engine vibration generated between the cover and the throttle body main body accumulates between the brush and the substrate to cause a contact failure and prevent the correct throttle opening from being detected. In addition, by providing the sensor unit in a deep place near the throttle bore, it is difficult to measure the brush pressing force when assembling the throttle body,
There is a problem that the number of work steps increases and the assembly cost increases.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a throttle control device for an internal combustion engine, which prevents sliding wear powder between parts and vibration wear powder between parts due to engine vibration from entering, thereby reducing the friction of the brush of the throttle sensor. A first object is to prevent a contact failure between substrates (resistors) and to detect a correct throttle opening, and a second object is to reduce assembling work steps and assembling costs. Subject. It is conceivable that a sensor chamber is formed outside the cover of the gear chamber, the sensor section is housed in the sensor chamber, and a breathing hole is provided in the chamber wall of the sensor chamber. In this case, the third problem is to prevent wear powder in the gear chamber from adhering to the sensor section of the sensor chamber through the breathing hole, so that the breathing hole is not blocked by water droplets entering the sensor chamber or the gear chamber. Is the fourth problem.

[0006]

According to the present invention, a throttle shaft rotatably (rotatably) traversing an intake passage is rotationally driven by a motor via a gear (reduction gear mechanism), and the throttle shaft is attached to the throttle shaft. In a throttle control device for an internal combustion engine that controls an intake air amount by opening and closing a fixed throttle valve, a brush of a sensor unit for detecting an opening degree of the throttle valve is attached to an outer end of the throttle shaft protruding from a cover. While fixing
A throttle control device for an internal combustion engine, wherein the sensor unit is housed in a sensor chamber formed outside a cover and is isolated from a gear chamber that houses the gear through a seal member. One configuration. The present invention relates to the first
In the configuration, a second configuration is such that the brush of the sensor unit is outwardly fixed outside a brush lever. According to a third aspect of the present invention, in the first and second configurations, a breathing hole is provided in a chamber wall of the sensor chamber that houses the sensor unit. According to a fourth configuration of the present invention, in the first to third configurations, the fixed shaft of the intermediate gear is supported by both the throttle body main body and the cover. The present invention
In the first configuration, a fifth configuration is such that a breathing hole is arranged at a position facing a portion deviated in the lateral direction from the resistor embedded in the sensor substrate. The present invention relates to the third or fifth aspect.
In the configuration, the breathing hole is arranged at a position facing a portion deviating outward from the brush moving range from the brush position when the throttle is fully used, which is less frequently used than the brush position when the throttle is fully closed. Configuration. The present invention
In the third configuration, a seventh configuration is such that an auxiliary hole having a diameter larger than that of the breathing hole is formed on one or both of the sensor chamber side and the gear chamber side of the breathing hole via a step.

[0007]

1 and 2 show a first embodiment of a throttle control device for an internal combustion engine according to the present invention. 1 and 2, a throttle shaft 2 is freely rotatably fitted across an intake passage 1a provided in the center of a throttle body main body 1, and a throttle valve 3 is fixed to the throttle shaft 2 with a screw 4. I have. The throttle shaft 2 is rotatably held by bearings 5a and 5b fitted to bearings 1b and 1c on the inner surface of the cylindrical body of the throttle body main body 1. A throttle gear 6 is fitted to one end (right side in FIG. 1) 2 a of the throttle shaft 2 to form an integral detent structure, which is fixed with a nut 7. A relief lever 8 is loosely fitted on the outer periphery of the throttle shaft 2, and the relief lever 8 is engaged with the throttle gear 6.

[0008] A coil spring 9 is mounted between the relief lever 8 and the throttle body 1, and the coil spring 9 urges the throttle valve 3 in a closing direction. A coil spring 10 is also mounted between the throttle gear 6 and the relief lever 8, and the coil spring 10 urges the relief lever 8 in a returning direction. A plug 11 is attached to an end of the other (left side in FIG. 1) tubular body, and the other end 2 b of the throttle shaft 2 is sealed in the throttle body 1. The throttle body 1 has
A motor 12 is fixed in parallel with the axis of the throttle shaft 2, and a drive gear 13 is fitted and integrally fixed to the tip of the output rotation shaft of the motor 12. The other end of the fixed shaft 14a is press-fitted and fixed to the throttle body 1, and the intermediate gear 14 is rotatably mounted on the outer periphery of the fixed shaft 14a.
The large diameter portion 14b of the gear 14 meshes with the drive gear 13, and the throttle gear 6 meshes with the small diameter portion 14c of the intermediate gear 14.

A cover 15 covers the gears 6, 13, 14, the relief lever 8, the coil springs 9, 10, and the like. The cover 15 is attached to the throttle body 1 by a seal ring (O-ring) 16.
It is assembled in a more airtight manner. The outer end 2c of the throttle shaft 2 protrudes from the insertion hole of the cover 15, and is sealed by a dust seal 17 to seal dust. A brush lever 18 is fitted and fixed to the outer end 2c of the throttle shaft 2, and a conductive elastic brush 18a
Are integrally fixed to the brush lever 18. Brush 18
a is fixed to the outside (the right side in FIG. 1) of the brush lever 18 outward. A sensor board 19 is assembled at a position facing the brush 18a, and four resistor elements 27 are attached to the sensor board 19.
(See FIG. 2) is embedded. The resistor 27 has an arc shape corresponding to the rotation locus of the brush 18a, and the tips of the four brushes 18a constantly press and contact each resistor 27. The sensor substrate 19 is in contact with and fixed to the cover 15 by a plate 21 via an elastic packing 20, and the plate 21 is fixed to the cover 15 by welding. As shown in FIG. 2, the cover 15 is fixed to the throttle body 1 with six bolts 26.

A wiring (not shown) for outputting the resistance value (opening detection value) of the resistor 27 of the sensor board 19 is
And a connector (not shown) formed integrally with the connector. With the above configuration, the brush 18a and the sensor substrate 19
The sensor section 22 is accommodated in a sensor chamber 24 formed by the cover 15 and the plate 21, and the sensor chamber wall of the cover 15
The gear chamber (gear train chamber) 23 is isolated by 15a.
At a substantially central portion of the sensor chamber wall 15a, a breathing hole 15b for allowing air (gas) in the sensor chamber 24 to escape is formed.
The breathing hole 15b should be provided in accordance with the amount of corrosive gas components generated from the synthetic resin or rubber used in the sensor chamber 24. If this is provided, the effect of preventing wear powder from entering is slightly reduced. Acts in the direction.

The location where the breathing hole 15b is provided is not limited to the sensor chamber wall 15a, but may be provided on the cover 15 or the plate 21 to allow gas to escape directly to the atmosphere. Further, a breathing hole 1d for a gear chamber is provided at an upper portion of the throttle body main body 1, and a water drainage hole 1e is provided at a position corresponding to a lowermost portion of the throttle body main body 1, so that water enters the gear chamber 23 by any chance. In some cases, it is configured to allow water to flow out. In addition, when water does not splash due to the on-board condition,
The use of the seal ring 16 can be eliminated. The front end (one end) of the fixed shaft 14a of the intermediate gear 14 is fitted into a shaft hole 15c provided in the cover 15, and the fixed shaft 14a is
And the throttle body 1 are supported on both shafts. An output signal (electric signal) is supplied to the motor 12 from a connector (not shown) integrally formed on the cover 15 with the electrode 15 d.
Is done through

Next, the first operation of the embodiment of the present invention will be described. When an electric signal from an ECU (not shown) is supplied to the motor 12 from the electrode 15d, the motor 12 rotates (rotates) in accordance with the electric signal, and the driving gear 13 at the end of the motor driving shaft drives the intermediate gear 14 to rotate. The large diameter portion 14b rotates. Then, the throttle gear 6 meshing with the small diameter portion 14c of the intermediate gear 14 rotates to open and close the throttle valve 3. The fixed shaft 14a of the intermediate gear 14 includes the throttle body 1 and the cover 15
Therefore, the driving force of the driving gear 13 is divided into two by the two bearings, and the length of the press-fitting portion on the throttle body 1 side can be reduced by half. In addition, since the amount of distortion of the fixed shaft 14a is also reduced by half, the amount of sliding between gears is also reduced, the amount of sliding friction powder generated is reduced, and the durability is improved.

Abrasion powder generated by sliding or vibration of the gears 13, 14, 6 and the coil springs 9, 10 is removed from the sensor chamber wall 15a.
And the dust seal 17 prevents entry into the sensor chamber 24, and adhesion between the brush 18a and the sensor substrate 19 is extremely reduced. Breathing hole 15 provided in sensor room wall 15a
It is more effective to prevent wear powder from entering as much as possible, but it is necessary to provide b in accordance with the generation of corrosive gas components generated from synthetic resins and rubbers used in the sensor chamber 24. There is. When the breathing hole 15b is provided, the air in the sensor chamber 24 can be circulated in cooperation with the dust seal 17, and the inside of the sensor chamber 24 can be updated with fresh air. The brush 18a is the outer end 2 of the throttle shaft 2.
c, that is, outside the cover 15 and the brush lever 18
When the throttle body 30 is assembled, the pressing force of the brush 18a against the sensor substrate 19 can be efficiently measured in a short time when the throttle body 30 is assembled. be able to.

In the first embodiment of the present invention, the breathing hole 15b
Is formed at a position (substantially at the center of the sensor chamber wall 15a) opposed to the substantially center of the arc-shaped resistor (sensor resistor) 27. As shown in FIG. 2, this position corresponds to an intermediate position between the position of the brush lever 18 when the throttle valve is fully closed and the position of the brush lever 18 when the throttle valve is fully opened. Since the breathing hole 15b is provided at the portion facing the position of the resistor 27 which is frequently used in this way, when the wear powder of the gear chamber 23 enters the sensor chamber 24 through the breather hole 15b, the wear powder is removed by the resistor powder. There is a high possibility that the sensor adheres to the frequently used portion of 27 and the sensor output signal becomes abnormal.

Further, in the first embodiment of the present invention, since the shape of the breathing hole 15b is a circular hole perpendicular to the surface of the sensor chamber wall 15a, water droplets that have entered the gear chamber 23 or the sensor chamber 24 are not affected by the water drop. When moving along the wall 15a, water droplets may flow into the round hole and block the round hole. When the round hole is closed with water drops,
The corrosive gas in the sensor chamber 24 cannot be discharged, and the corrosive gas may corrode the resistor 27 and the brush 18a.

FIGS. 3 and 4 show a second embodiment of the throttle control device for an internal combustion engine according to the present invention. Embodiment 2
The first embodiment of the present invention solves the above-mentioned disadvantages of the first breathing hole 15b, and is characterized by the position and shape of the breathing hole (hole) 15b. In the description of the second embodiment, the same members as those of the first embodiment are provided.
The same reference numerals are given and the description of those parts is omitted.

As clearly shown in FIGS. 3 and 4, the second breathing hole 15b of the embodiment is opened at the upper end of the sensor chamber 24, and this position is located in the lateral direction (the sensor). (On the substrate 19). In addition, the position of the breathing hole 15b is opposed to a portion of the brush position when the throttle is fully opened, which is less frequently used than the brush position when the throttle is fully closed, and which is outside the moving range of the brush lever 18 and the brush 18a. ing.

As described above, since the breathing hole 15b is disposed at a position opposed to a portion which is least related to the use position of the brush 18a, the abrasion powder of the gear chamber 23 enters the sensor chamber 24 through the breathing hole 15b. Then, the abrasion powder adheres to an unused portion (a portion where the brush 18a does not contact) or a least frequently used portion of the resistor 27, and the effect of the abrasion dust on the sensor output signal is reduced. Further, since the abrasion powder adheres to the unused portion or the least frequently used portion of the resistor 27, it is possible to prevent the abrasion dust from being scattered by the brush 18a to the entire sensor substrate 19 and the resistor 27. Reference numeral 38 denotes a water pool groove.

As clearly shown in FIG. 3 (b), in the second embodiment, one or both of the sensor chamber 24 side and the gear chamber 23 side of the breathing hole 15b is perpendicular to the axis of the breathing hole 15b. Step 3
A diameter sufficiently larger than the breathing hole 15b through 2, 33 (2 to 3
Auxiliary holes 34 and 35 (double diameter) are formed. here,
Since the axial length of the breathing hole 15b is equal to the thickness of the sensor chamber wall 15a, the auxiliary holes 34 and 35 are mainly formed inside the cylindrical bodies 36 and 37, and the auxiliary holes 34 and 35 have the same diameter. Has been. If there is no possibility that water drops will enter the gear chamber 23, the step 33 on the gear chamber 23 side, the auxiliary hole 35, the cylindrical body
37 can be omitted, and when there is no possibility that water droplets enter the sensor chamber 24, the step 32 on the sensor chamber 24 side,
The auxiliary hole 34 and the cylindrical body 36 can be omitted.

Due to the presence of the steps 32, 33 and the auxiliary holes 34, 35, when water droplets entering the gear chamber 23 or the sensor chamber 24 move along the sensor chamber wall 15a, the water droplets are removed by the auxiliary holes 34, 35 and the step holes. The water droplets caught by the parts 32 and 33 are prevented from reaching the breathing hole 15b and blocking the breathing hole 15b with moisture. Therefore, the discharge of the corrosive gas in the sensor chamber 24 is not hindered.

[0021]

According to the first aspect of the present invention, the sensor chamber is constituted by the cover and the plate separately from the gear chamber, and the sensor section is accommodated in the sensor chamber. Does not enter the sensor chamber and does not accumulate between the brush and the sensor substrate to cause a contact failure. Therefore, the ability to detect the throttle opening is not reduced, and the correct throttle opening is detected. be able to.
According to the second aspect, the brush is fixed outwardly to the outside of the brush lever, so that it is easy to measure the pressing force of the brush when assembling the throttle body, and the assembling operation man-hour can be reduced. Costs can be reduced.

According to the third aspect of the present invention, a breathing hole is provided in a sensor chamber wall for accommodating the sensor section, so that a corrosive gas generated from synthetic resin or rubber used in the sensor chamber is scavenged to remove the brush or the like. Corrosion of the sensor substrate can be prevented. According to the fourth aspect, since both ends of the fixed shaft of the intermediate gear are supported, the driving force of the drive gear is divided into two by the two bearings, and the length of the press-fitted portion into the throttle body can be reduced by half. , The amount of sliding between gears also decreases, the amount of sliding wear powder generated decreases, and the durability of the gears improves.

According to the fifth aspect of the present invention, since the breathing hole is disposed at a position facing the portion laterally deviated from the resistor embedded in the sensor substrate, abrasion powder in the gear chamber passes through the breathing hole. When entering the sensor chamber, the abrasion powder hardly adheres to the resistor, and the influence of the abrasion powder on the sensor output signal is reduced. According to a sixth aspect of the present invention, the breathing hole is disposed at a position opposing a portion of the brush that is less frequently used than the brush position when the throttle is fully open compared to the brush position when the throttle is fully closed and that is deviated outward in the brush moving range. ing. Therefore, when the abrasion powder in the gear chamber enters the sensor chamber through the breathing hole, the abrasion powder adheres to an unused portion (a portion where the brush does not contact) or a least frequently used portion of the resistor, and the sensor output is reduced. The effect of the abrasion powder on the signal is reduced. Also,
The abrasion powder adheres to the unused portion or the least frequently used portion of the resistor, so that it is possible to prevent the abrasion dust from being scattered to the entire sensor substrate and resistor by the brush.

According to a seventh aspect of the present invention, the sensor chamber side of the breathing hole is provided.
An auxiliary hole having a diameter larger than the breathing hole was formed in one or both of the gear chamber sides via a step. Therefore, when a water droplet that has entered the gear chamber or the sensor chamber moves along the sensor chamber wall, the water droplet is caught by the auxiliary hole and the step, preventing the water droplet from reaching the breathing hole and closing the breathing hole with moisture. Is done. Therefore, discharge of corrosive gas in the sensor chamber is not hindered.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a throttle control device for an internal combustion engine of the present invention.

FIG. 2 is a right side view of FIG. 1 (turned clockwise by 90 °).

3 (a) is a sectional view showing a second embodiment of the throttle control device for an internal combustion engine according to the present invention, and FIG. 3 (b) is an enlarged view of a breathing hole portion in FIG. 3 (a). It is.

FIG. 4 is a right side view of FIG. 3 (a) (turned clockwise by 90 °).

[Explanation of symbols]

 1: throttle body 1a: intake passage 2: throttle shaft 2c: outer end 3: throttle valve 6: throttle gear 12: motor 13: drive gear 14: intermediate gear 14a: fixed shaft 15: cover 15a: sensor chamber wall 15b : Breathing hole 17: Dust seal 18: Brush lever 18a: Brush 22: Sensor part 23: Gear room 24: Sensor room 27: Resistor 32: Step part 33: Step part 34: Auxiliary hole 35: Auxiliary hole

Continuation of the front page (72) Inventor Nao Kitamura 1-1, Kyowa-cho, Obu-shi, Aichi 1 Ai San Kogyo Co., Ltd. (72) Inventor Takashi Tsuge 1-1-1, Kyowa-cho, Obu-shi, Aichi 3G065 CA00 DA05 DA06 DA15 HA06 HA12 HA15 HA21 HA22

Claims (7)

[Claims] An internal combustion engine in which a throttle shaft rotatably provided across an intake passage is rotationally driven by a motor via a gear, and an intake air amount is controlled by opening and closing a throttle valve fixed to the throttle shaft. In the throttle control device, the brush of the sensor unit for detecting the opening of the throttle valve is fixed to the outer end of the throttle shaft protruding from the cover, and the sensor unit is formed outside the cover. A throttle control device for an internal combustion engine, wherein the throttle control device is housed in a sensor chamber and is isolated from a gear chamber housing the gear via a seal member. 2. The throttle control device for an internal combustion engine according to claim 1, wherein the brush of the sensor section is fixed outwardly outside a brush lever. 3. The throttle control device for an internal combustion engine according to claim 1, wherein a breathing hole is provided in a chamber wall of the sensor chamber accommodating the sensor unit. 4. A fixed shaft of the intermediate gear is supported by both the throttle body main body and the cover.
The throttle control device for an internal combustion engine according to any one of the above. 5. A resistor embedded in a sensor substrate,
4. The throttle control device for an internal combustion engine according to claim 3, wherein a breathing hole is arranged at a position facing the portion deviated in the lateral direction. 6. A breathing hole is located at a position facing a portion of the brush that is less frequently used than the brush position when the throttle is fully open compared to the brush position when the throttle is fully closed and that is outside the range of movement of the brush. 6. The throttle control device for an internal combustion engine according to 3 or 5. 7. The throttle control device for an internal combustion engine according to claim 3, wherein an auxiliary hole having a diameter larger than that of the breathing hole is formed at one or both of the sensor chamber side and the gear chamber side of the breathing hole via a step.