JP3745573B2 - Throttle control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a throttle control device for controlling the amount of intake air of an internal combustion engine, and relates to improving the reliability of a throttle sensor for detecting the opening of a throttle valve.
[0002]
[Prior art]
Conventionally, an electric throttle control device that controls an engine speed by opening and closing a throttle valve fixed to a throttle shaft via a gear (reduction gear mechanism) by a motor that rotates according to a signal from an ECU (Electronic Control Unit). Detects a drive gear fixed to the motor output shaft, a throttle gear fixed to the throttle shaft, an intermediate gear that mediates the two gears, a return spring that biases the throttle valve in the closing direction, and a throttle valve opening degree. For example, a throttle sensor unit (hereinafter simply referred to as “sensor unit”). A throttle control device is known in which both ends of the throttle shaft project outward from the bearings of the throttle 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. (See, for example, JP-A-10-159591).
[0003]
In the prior art described in Japanese Patent Laid-Open No. 10-159591, the speed reduction gear mechanism is connected to one end of the throttle shaft and the sensor unit is connected to the other end, so that the gear case is connected to one end of the throttle shaft. And a sensor case at the other end, which has a problem that the structure of the throttle body is complicated and the number of parts increases. Therefore, it is conceivable to improve the conventional technique described in Japanese Patent Application Laid-Open No. 10-1559591 and arrange a reduction gear mechanism, a sensor unit, etc. on one side of the throttle shaft so as to be accommodated in one room. (See Japanese Patent Application No. 11-68855 related to the applicant's application). 2 and 11, the drive gear 20, the intermediate gear 22, the throttle gear 18, the fully closed position adjusting screw 23, the throttle sensor brush 16, the substrate 17, and the like are surrounded by the cover 32 in FIG. 2 and FIG. It is housed in the room.
[0004]
When the reduction gear mechanism, sensor unit, etc. are housed in one room, the sliding wear powder generated between the gears or between the spring and the guide abutting against it is between the brush of the sensor unit and the substrate (resistor). If it enters and accumulates, contact failure may occur and the correct throttle opening may not be detected. As a countermeasure, sliding friction between parts is achieved by attaching a sensor part consisting of a brush and a substrate in the vicinity of the throttle bore part of the throttle shaft and covering it with a cylindrical cover with a lid that is configured to fit into the throttle body body. Although it is conceivable to prevent the ingress of powder, vibration friction powder due to engine vibration generated between the cover and the throttle body body accumulates between the brush and the substrate, resulting in poor contact, and the correct throttle opening cannot be detected. The fear cannot be denied. In addition, by providing the sensor part in a deep part near the throttle bore, the work for measuring the brush pressing force at the time of assembling the throttle body is difficult, and there is a problem that the work man-hour increases and the assembling cost increases. .
[0005]
[Problems to be solved by 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 from entering between parts due to engine vibration, and poor contact between the brush and the substrate (resistor) of the throttle sensor. It is a first problem to be able to detect the correct throttle opening and to reduce the assembling cost by reducing the assembling work man-hours. It is conceivable that a sensor chamber is formed outside the gear chamber cover, the sensor portion is accommodated 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 portion 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. This is the fourth problem.
[0006]
[Means for Solving the Problems]
The present invention relates to an internal combustion engine in which a throttle shaft provided so as to be able to rotate across an intake passage is rotated 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, a sensor brush for detecting the opening degree of the throttle valve is fixed to the outer end portion of the throttle shaft protruding from the cover, and the sensor portion is formed on the outside of the cover. It is accommodated in a room, accommodates the gear, is isolated from the gear chamber adjacent to the sensor chamber, and seals the throttle shaft and the insertion hole of the cover for projecting the outer end portion of the throttle shaft with a seal member . And a breathing hole for allowing air in the sensor chamber to escape to the chamber wall on the gear chamber side of the sensor chamber By comprising a first structure. The present invention, in the first configuration, a resistive element embedded in the sensor substrate, at a position opposed to the outside the transverse portion, and a second configuration in that a breathing hole. In the first configuration , the present invention provides a breathing hole at a position opposite to a portion outside the brush movement range from the brush position when the throttle is fully opened, which is less frequently used than the brush position when the throttle is fully closed. The arrangement is the third configuration . The present invention, in the first configuration, the sensor chamber side of the breathing hole, and a fourth structure that it has an auxiliary bore of larger diameter than the ventilation hole via a step portion on one or both of the gear chamber side.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
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 rotatably fitted across an intake passage 1a provided in the center of the throttle body 1, and a throttle valve 3 is fixed to the throttle shaft 2 with a screw 4. Yes. The throttle shaft 2 is rotatably held by bearings 5a and 5b fitted to bearing portions 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 2 a (right side in FIG. 1) of the throttle shaft 2 to form an integral rotation preventing structure, and is fixed by 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 body 1, and the throttle valve 3 is urged by the coil spring 9 in the closing direction. A coil spring 10 is also mounted between the throttle gear 6 and the relief lever 8, and the relief lever 8 is biased by the coil spring 10 in a returning direction. A plug 11 is attached to the end of the other cylindrical body (left side in FIG. 1), and the other end 2 b of the throttle shaft 2 is sealed in the throttle body 1. A motor 12 is fixed to the throttle body 1 in parallel with the axis of the throttle shaft 2, and a drive gear 13 is fitted and 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 an intermediate gear 14 is rotatably assembled to the outer periphery of the fixed shaft 14a. The large diameter portion 14b of the intermediate gear 14 is engaged with the drive gear 13, and the throttle The gear 6 is configured to mesh with the small diameter portion 14c of the intermediate gear 14.
[0009]
A cover 15 covers the gears 6, 13, 14, the relief lever 8, the coil springs 9, 10, etc., and the cover 15 is assembled to the throttle body main body 1 while being kept airtight by a seal ring (O-ring) 16. The outer end portion 2 c of the throttle shaft 2 protrudes from the insertion hole of the cover 15 and is sealed by sealing dust with a dust seal 17. A brush lever 18 is fitted and fixed to the outer end 2 c of the throttle shaft 2, and a brush 18 a made of a conductive elastic body is integrally fixed to the brush lever 18. The brush 18a is fixed to the outside (right side in FIG. 1) of the brush lever 18 outward. A sensor substrate 19 is assembled at a position opposite to the brush 18a, and four resistors 27 (see FIG. 2) are embedded in the sensor substrate 19. The shape of the resistor 27 has an arc shape corresponding to the rotation trajectory of the brush 18a, and the tips of the four brushes 18a always press and contact each resistor 27. The sensor substrate 19 is in contact with and fixed to the cover 15 by a plate 21 through 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 main body 1 with six bolts 26.
[0010]
Wirings (not shown) for outputting the resistance value (opening detection value) of the resistor 27 of the sensor substrate 19 are led out from a connector part (not shown) formed integrally with the cover 15. With the above-described configuration, the sensor unit 22 including the brush 18a and the sensor substrate 19 is accommodated in the sensor chamber 24 formed by the cover 15 and the plate 21, and the gear chamber (gear train chamber) is formed by the sensor chamber wall 15a of the cover 15. ) Isolated from 23. A breathing hole 15b for escaping air (gas) in the sensor chamber 24 is provided in the substantially central portion of the sensor chamber wall 15a. The breathing hole 15b should be provided according to the amount of corrosive gas components generated from the synthetic resin or rubber used in the sensor chamber 24, and if this is provided, the effect of preventing wear powder from entering is slightly diminished. Acts on direction.
[0011]
The place 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 the gas to escape directly into the atmosphere. In addition, a gear chamber breathing hole 1d is provided at the upper part of the throttle body main body 1, and a water drain hole 1e is provided at a position corresponding to the lowermost part 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. It should be noted that the use of the seal ring 16 can be abolished when water is not applied due to the in-vehicle state. The distal 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 supported on both shafts by the cover 15 and the throttle body body 1. Supply of an output signal (electrical signal) to the motor 12 is performed through an electrode 15d from a connector portion (not shown) formed integrally with the cover 15.
[0012]
Next, the first operation of the embodiment of the present invention will be described. When an electrical signal from an ECU (not shown) is supplied from the electrode 15d to the motor 12, the motor 12 rotates (rotates) in accordance with the electrical signal, and the intermediate gear 14 is driven by the drive gear 13 at the tip of the motor drive shaft. 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. Since the fixed shaft 14a of the intermediate gear 14 is pivotally supported by both the throttle body 1 and the cover 15, the driving force of the drive gear 13 is divided by both bearings, and the length of the press-fitting portion on the throttle body 1 is halved. can do. Further, since the amount of strain of the fixed shaft 14a is also halved, the amount of sliding between the gears is reduced, the amount of sliding friction powder generated is reduced, and the durability is improved.
[0013]
The abrasion powder generated by the sliding or vibration of the gears 13, 14, 6 and the coil springs 9, 10 is blocked by the sensor chamber wall 15a and the dust seal 17, and is prevented from entering the sensor chamber 24. Adhesion with the substrate 19 is extremely reduced. Although it is effective to prevent the introduction of abrasion powder if the breathing hole 15b provided in the sensor chamber wall 15a is not provided as much as possible, the corrosive gas generated from the synthetic resin or rubber used in the sensor chamber 24 It is necessary to provide according to the generation situation of the component. 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 fixed to the outer end 2c of the throttle shaft 2, that is, the outer side of the cover 15 and the outer side of the brush lever 18, so that when the throttle body 30 is assembled, the brush 18a to the sensor board 19 is assembled. Can be measured efficiently in a short time, and the assembly man-hours can be reduced.
[0014]
In the first embodiment of the present invention, the breathing hole 15b is formed at a position facing substantially the center of the arc-shaped resistor (sensor resistor) 27 (substantially the center position of the sensor chamber wall 15a). 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 open. Since the breathing hole 15b is located at the portion facing the position of the resistor 27 that is frequently used in this way, when the wear powder in the gear chamber 23 enters the sensor chamber 24 through the breathing hole 15b, the wear powder is resisted. There is a high possibility that the sensor output signal will become abnormal because it adheres to 27 frequently used parts.
[0015]
In the first embodiment of the present invention, since the shape of the breathing hole 15b is a round hole perpendicular to the surface of the sensor chamber wall 15a, water drops that have entered the gear chamber 23 or the sensor chamber 24 enter the sensor chamber wall 15a. When moving along, there is a possibility that water droplets flow into the round hole and close the round hole. If the round hole is blocked with water droplets, the corrosive gas in the sensor chamber 24 cannot be discharged, and the resistor 27 and the brush 18a may be corroded by the corrosive gas.
[0016]
3 and 4 show a second embodiment of the throttle control device for an internal combustion engine of the present invention. The second embodiment eliminates the above-mentioned drawbacks of the first breathing hole 15b of the present invention 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 in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted.
[0017]
As clearly shown in FIGS. 3 and 4, the second breathing hole 15 b of the embodiment is opened at the upper end of the sensor chamber 24, and this position is located laterally from the resistor 27 (on the sensor substrate 19. It faces the part on the sensor substrate 19 that is off. In addition, the position of the breathing hole 15b is opposed to a portion that deviates in the outward direction of the movement range of the brush lever 18 and the brush 18a from the brush position when the throttle is fully opened compared to the brush position when the throttle is fully closed. ing.
[0018]
Thus, since the breathing hole 15b is arranged at the position opposite to the portion most unrelated to the use location of the brush 18a, when the abrasion powder in the gear chamber 23 enters the sensor chamber 24 through the breathing hole 15b, The wear powder adheres to the unused portion of the resistor 27 (the portion where the brush 18a does not contact) or the least frequently used portion, and the influence of the wear powder 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 powder from being scattered by the brush 18a over the entire sensor substrate 19 and the resistor 27. Reference numeral 38 denotes a water pool groove.
[0019]
As clearly shown in FIG. 3 (b), in the second embodiment, a step portion perpendicular to the axis of the breathing hole 15b is provided on one or both of the breathing hole 15b on the sensor chamber 24 side and the gear chamber 23 side. Auxiliary holes 34 and 35 having a diameter (2 to 3 times larger) than the breathing hole 15b are formed through 32 and 33. Here, since the axial length of the breathing hole 15b is made 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 hole 34 and the auxiliary hole 35 are formed. Are made the same diameter. If there is no possibility of water droplets entering the gear chamber 23, the step 33, the auxiliary hole 35, and the cylindrical body 37 on the gear chamber 23 side can be omitted, and water droplets can enter the sensor chamber 24. If there is no possibility of doing so, the stepped portion 32, the auxiliary hole 34, and the cylindrical body 36 on the sensor chamber 24 side can be omitted.
[0020]
Due to the presence of the step portions 32 and 33 and the auxiliary holes 34 and 35, when the water droplets entering the gear chamber 23 or the sensor chamber 24 move along the sensor chamber wall 15a, the water droplets are moved to the auxiliary holes 34 and 35 and the step portions 32, It is captured at 33, and water droplets 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]
【The invention's effect】
According to a first aspect of the present invention, a sensor chamber is constituted by a cover and a plate separately from the gear chamber, the sensor portion is accommodated in the sensor chamber, and a through hole of the cover for projecting the outer end portion of the throttle shaft and the throttle shaft is provided. Is provided with a breathing hole through which the air in the sensor chamber is released on the chamber wall on the gear chamber side of the sensor chamber that houses the sensor unit. Detecting the correct throttle opening without entering the sensor chamber and without accumulating between the brush and the sensor substrate and causing poor contact, and therefore the ability to detect the throttle opening is not reduced. can together with possible, to prevent corrosion of the brush and the sensor substrate by scavenging corrosive gas generated from the synthetic resins and rubbers used in the sensor chamber
[0022]
According to the second aspect of the present invention, since the breathing hole is disposed at a position facing the portion laterally removed from the resistor embedded in the sensor substrate, the wear powder in the gear chamber passes through the breathing hole and enters the sensor chamber. When entering, the wear powder hardly adheres to the resistor, and the influence of the wear powder on the sensor output signal is reduced. According to the third aspect of the present invention, the breathing hole is disposed at a position facing a portion that is less frequently used than the brush position when the throttle is fully closed, and that is out of the brush movement range in the outward direction from the brush position when the throttle is fully open. ing. Therefore, when wear dust in the gear chamber enters the sensor chamber through the breathing hole, the wear dust adheres to the unused portion of the resistor (the portion where the brush does not contact) or the least frequently used portion, and the sensor output The influence of wear particles on the signal is reduced. In addition, since the wear powder adheres to the unused portion or the least frequently used portion of the resistor, it is possible to prevent the wear powder from being scattered by the brush over the entire sensor substrate / resistor.
[0023]
In the fourth aspect of the present invention, an auxiliary hole having a diameter larger than that of the breathing hole is formed on one or both of the breathing hole on the sensor chamber side and the gear chamber side via a stepped portion. Therefore, when water droplets that have entered the gear chamber or sensor chamber move along the sensor chamber wall, the water droplets are caught by the auxiliary hole and the stepped portion, and the water droplets do not reach the breathing hole and block 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 according to the present invention.
FIG. 2 is a right side view of FIG. 1 (rotated right by 90 °).
FIG. 3 (a) is a sectional view showing a second embodiment of the throttle control device for an internal combustion engine of the present invention, and FIG. 3 (b) is an enlarged view of the breathing hole portion of FIG. 3 (a). It is.
FIG. 4 is a right side view of FIG. 3A (rotated right 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 section
23: Gear room
24: Sensor room
27: Resistor
32: Stepped part
33: Stepped part
34: Auxiliary hole
35: Auxiliary hole

Claims (4)

In a throttle control device for an internal combustion engine, in which a throttle shaft that is pivotable 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 ,
While fixing the brush of the sensor unit for detecting the opening degree of the throttle valve to the throttle shaft outer end protruding from the cover,
The sensor unit is accommodated in a sensor chamber formed outside the cover, and the gear is accommodated and isolated from a gear chamber adjacent to the sensor chamber ,
Sealing the throttle shaft and the insertion hole of the cover for projecting the outer end of the throttle shaft with a seal member ;
A throttle control device for an internal combustion engine , wherein a breathing hole for allowing air in the sensor chamber to escape is provided in a chamber wall on the gear chamber side of the sensor chamber . A resistive element embedded in the sensor substrate, at a position opposed to the outside the transverse portion, a throttle control apparatus for an internal combustion engine according to claim 1 wherein placing the said ventilation hole. From the brush position at low throttle fully open frequently used as compared with the throttle fully closed state of the brush position, the internal combustion according to claim 1 wherein placing the said ventilation hole at a position opposed to a portion deviated outward of the movement range of the brush Engine throttle control device. The respiration sensor chamber side of the hole, the throttle control apparatus for an internal combustion engine according to claim 1, wherein via a step portion on one or both of the gear chamber side to form an auxiliary hole of larger diameter than the ventilation hole.

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