WO2000063542A1

WO2000063542A1 - Intake gas amount control device of internal combustion engine

Info

Publication number: WO2000063542A1
Application number: PCT/JP2000/002261
Authority: WO
Inventors: Katsunari Takagi; Mikihiko Suzuki; Kensuke Imada; Takeshi Sugiyama
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 1999-04-15
Filing date: 2000-04-07
Publication date: 2000-10-26

Abstract

An intake gas amount control device of an internal combustion engine which is small in size and weight, excellent in mountability, and small in number of parts, and is improved in engine speed controllability and meshing of speed reduction gears, comprising a synthetic resin housing forming, inside the device, an intake gas passage of the internal combustion engine, a valve stem installed rotatably in the intake gas passage, a throttle valve which is installed on the valve stem and controls a flowing air amount in the intake gas passage, a motor which is insert-formed in the housing and drives the valve stem through a speed reduction mechanism, and a sensor which is installed near a connection part between the valve stem and the speed reduction mechanism and detects the rotating angle of the valve stem, wherein the drive shaft of the motor and the valve stem are disposed in parallel with each other, and a resin contraction compensation is applied to a synthetic resin housing forming mold so that a deformation due to its contraction does not occur at the time of cooling of the resin.

Description

Description Intake air volume control system for internal combustion engine

The present invention relates to an intake amount control device that controls an intake air amount according to a traveling state of a vehicle. Background art

FIG. 7 shows a configuration of a conventional intake air amount control device for an internal combustion engine. In the figure, 1 is a housing of a throttle body made of an aluminum alloy die-cast, 2 is an intake passage provided inside the housing 1, and 3 is a throttle which is rotatably supported at both ends of the housing 1 and penetrates the intake passage 2 and restricts the air. The throttle valve 4 is a valve shaft to which the valve 4 is attached. The throttle valve 4 rotates the intake passage 2 from the fully closed position to the fully open position by rotating the valve shaft 3 to control the amount of intake air. A sensor 5 for detecting a rotation angle of the valve shaft 3 is arranged at one end of the valve shaft 3, and a speed reduction mechanism driven by a motor 6 is connected to the other end. Reference numeral 7 denotes a connector for externally connecting the sensor 5.

The motor 6 includes a rotor 9 fixed to a drive shaft 8 and a stator 10 .The drive shaft 8 is arranged on the same axis as the valve shaft 3 and has a gear 8 a at the tip, Driven by being coupled to the valve shaft 3 via a reduction mechanism composed of reduction gears 11, 13 and a reduction gear support 12. The stator 10 is held by a synthetic resin housing 15 that integrally forms a connector 14 for external opening of the motor 6, and the motor housing 15 is connected to one end of the throttle body housing 1. It is fixed by screws and the slot poddy and the motor 6 are integrated. As described above, the sensor 5 is screwed to the end of the throttle body opposite to the motor mounting portion.

In the conventional intake air amount control device shown in FIG. 7, the motor 6 is controlled by a control device (not shown) and receives the feed pack by the sensor 5. Drives et valve shaft 3, but sets retain閧度the throttle valve 4 so that the intake amount determined by the traveling state of the accelerator state and the vehicle, in recent years, in order to suppress the exhaust gas containing C 0 ₂ In addition, as the miniaturization of each part of the vehicle is promoted, the throttle pod, the motor 6 and the sensor 5 are separately formed, and there is a limit to the reduction in size and weight in a configuration in which these are integrally assembled. The housing 1 of the torque body also had the rigidity required for assembling the motor 6 and the like, and required high precision in the bore diameter, so it was necessary to use aluminum alloy die casting at the expense of weight. In addition, since the motor 6 and the sensor 5 are mounted on both sides of the valve shaft 3 in the axial direction, the axial dimension is increased, so that the assemblability to the internal combustion engine is poor, and the number of parts has to be increased. I didn't get it.

Further, simply replacing the material of the housing of the conventional intake air amount control device shown in Fig. 7 with a synthetic resin would result in poor roundness and dimensions of the bore diameter of the intake passage in the intake control section, and poor dimensional accuracy of the high-speed gear portion. The fully closed leakage flow rate is large and the desired engine idle speed cannot be controlled. ② Poor throttle opening controllability due to poor meshing of the reduction gear (gear pack lash is large and does not operate smoothly). ③ Problems such as gear abrasion occur due to poor meshing of the reduction gear, and bad seals due to warpage of the cover mounting surface.

The present invention has been made in order to solve such problems, and it is possible to improve the mountability by reducing the weight and the axial dimension, to improve the controllability of the engine speed, and to improve the engagement of the reduction gear. It is another object of the present invention to provide an intake air amount control device for an internal combustion engine capable of reducing the number of parts and improving the assemblability accordingly. Disclosure of the invention

An intake air amount control device for an internal combustion engine according to the present invention includes: a housing made of a synthetic resin forming an intake passage of the internal combustion engine therein; a valve shaft rotatably provided in the intake passage of the housing; A throttle valve mounted on the housing to control the amount of air flowing through the intake passage, and insert molded into the housing, The motor includes a motor that drives a valve shaft through a speed reduction mechanism, and a sensor that is provided near a joint between the valve shaft and the speed reduction mechanism and that detects a rotation angle of the valve shaft.

In addition, the drive shaft of the motor and the valve shaft are arranged in parallel.

In addition, the synthetic resin housing is designed to anticipate changes in dimensions such as the roundness of the intake passage due to shrinkage during resin molding and cooling, and the mounting pitch of the motor drive shaft and valve shaft. Correct the mold dimensions, or eliminate roundness in the vicinity of the intake passage, which requires accuracy such as roundness and passage diameter, etc., and provide reinforcement ribs at a position away from the intake passage. It is manufactured by reducing the dimensional change due to shrinkage during resin cooling and ensuring accuracy.

Furthermore, the motor is constituted by a DC motor or a DC brushless motor.

Furthermore, the connector for external opening of the motor and the connector for external opening of the sensor are formed integrally with the housing.

Further, the external outlet connector of the motor and the external outlet connector of the sensor are formed integrally with the cover covering the end face of the housing.

In addition, one of the external connector for the motor and the external connector for the sensor is formed integrally with the housing and the other with the cover.

Furthermore, the connector for externally connecting the motor and the connector for externally connecting the sensor are integrally integrated and molded. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a partial cross-sectional top view showing a structure of an intake air amount control device according to Embodiment 1 of the present invention.

FIG. 2 is a partial cross-sectional top view showing the structure of the intake air amount control device according to Embodiment 2 of the present invention. FIG. 3 is a schematic sectional view showing a molding die without resin shrinkage compensation for molding the resin housing of the intake air amount control device.

FIG. 4 is a schematic sectional view showing the housing of the intake air amount control device formed by using the forming die of FIG.

FIG. 5 is a schematic cross-sectional view showing a molding die with resin shrinkage compensation for molding the resin housing of the intake air amount control device of the present invention.

FIG. 6 is a schematic sectional view showing the housing of the intake air amount control device formed by using the forming die of FIG.

FIG. 7 is a partial cross-sectional top view showing the structure of a conventional intake air amount control device. BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1

FIG. 1 is a partial cross-sectional view of an intake air amount control device for an internal combustion engine according to a first embodiment of the present invention. In the figure, reference numeral 16 denotes a throttle body housing, in which an intake passage 2 for supplying intake air to the internal combustion engine 2 has an intake control section 17 having an inner diameter, and a motor storage section 18 for storing the motor 6 is the same. It is molded integrally with synthetic resin.

Numeral 3 is a valve shaft which is rotatably supported at both ends by a bearing 19 provided in an intake control section 17 of a housing 16, penetrates the intake passage 2 and has a throttle valve 4 attached thereto. The valve 4 is configured to rotate the intake passage 2 from the fully closed position to the fully open position by rotating the valve shaft 3 to control the amount of intake air, and a motor shaft is provided at one end of the valve shaft 3. And a speed reduction mechanism driven by the motor.

The stator 10 of the motor 6 is attached to the motor housing 18 of the housing 16 by insert molding, and the rotor 9 having the drive shaft 8 has the drive shaft 8 of the motor housing 18 of the housing 16. Both ends are supported by bearings 20 and 21 provided on the shaft, are arranged in parallel with the valve shaft 3, and a gear 8 a is attached to the tip of the driving shaft 8. 1 1 is a reduction gear that forms part of the reduction mechanism, and cooperates with other gears (not shown) to rotate the motor Slow down the rotation and drive the valve shaft 3. Reference numeral 2 denotes a sensor, which is provided in the vicinity of a connection portion of the valve shaft 3 with the deceleration 4 and detects the rotation angle of the valve shaft 3 to control the driving position of the motor 6. Reference numeral 23 denotes a connector integrally formed with the housing 16 and integrated into the sensor 22 and an external outlet of the motor 6, and 24 denotes a drive of the valve shaft 3 by the motor 6. It is a cover to cover. A DC motor is used for motor 6, and a DC brushless motor is used for further reliability.

In addition, in the housing 16 of the intake air amount control device shown in Fig. 1, the vicinity of the intake passage 2 which requires accuracy such as roundness and passage diameter as resin shrinkage compensation, and motor 6 or motor 6 It is also effective to reduce the amount of resin by providing a gap G by eliminating the meat between the storage sections 18. Further, a reinforcing rib R is provided at a position distant from the suction passage 2, so that a change in dimension due to shrinkage during cooling of the resin can be reduced to ensure accuracy.

Fig. 3 is a schematic cross-sectional view of a molding die 35 for manufacturing the housing 16 of the intake air amount control device by resin molding, and Fig. 4 uses the molding die 35 of Fig. 3. The housing 36 of the intake air amount control device formed in this way is shown in a sectional view. The molding die shown in Fig. 3 takes into account deformation due to resin shrinkage, such as the required change in roundness and dimensions due to the shrinkage of the housing material due to the synthetic resin due to the molding resin cooling. Not. Accordingly, the cross-sectional shape of the obtained intake passage 37 of the housing 36 is such that the inner diameter in the direction of the axis A1 of the valve shaft is D1 and the inner diameter in the direction perpendicular to the axis A1 is shorter than D1. It is an ellipse of D2. In addition, since the resin around the intake passage 37 is deformed due to resin shrinkage, the motor housing 38 protruding from the main body of the housing 36 is also distorted, and its axis A 2 becomes the axis A 1 of the valve shaft. It is no longer parallel to.

FIG. 5 is a schematic cross-sectional view of a molding die 40 with resin shrinkage compensation for manufacturing the housing 16 of the intake air amount control device by resin molding. FIG. 6 shows the molding of FIG. The housing 16 of the intake air amount control device formed by using the mold 40 is shown in a sectional view. The molding die 40 shown in Fig. 5 is deformed due to shrinkage during molding resin cooling because the housing material is synthetic resin. In addition, resin shrinkage compensation is performed by considering deformation due to resin shrinkage such as required roundness of inner diameter and change in dimensions. As a typical example of the molding die 40 shown in FIG. 5 that is significantly different from the molding die 35 shown in FIG. 3, the hollow portion forming the intake passage 2 of the housing 16 is The cross section of the child 4 2 is not a perfect circle, and the diameter D 3 in the direction of the axis A 1 of the valve shaft is shorter than the diameter D 4 in the direction perpendicular to the axis A 1. Is formed in a distorted shape, and in particular, the axis A 3 of the cavity 43 forming the motor housing 18 has an intake passage 4 with respect to the axis A 1 of the valve shaft. For example, it is inclined in the direction approaching as it moves away from the center of 1.

As described above, according to the present invention, since the housing material is a synthetic resin, the housing is deformed by shrinkage during cooling of the molding resin, and the roundness and dimensions of the inner diameter are changed. In addition, resin shrinkage compensation is performed as an elliptical shape (molded with a mold whose shape and dimensions are corrected to allow for deformation). It is also effective as a resin shrinkage compensation to reduce the amount of resin by eliminating the wall between the vicinity of the intake passage and the motor, which requires accuracy such as roundness and passage diameter, etc. Further, a reinforcing rib is provided at a position distant from the intake passage, so that a change in dimensions due to shrinkage during resin cooling can be reduced to ensure accuracy.

In the housing 16 shown in FIG. 6 obtained by using such a molding die 40, the cross-sectional shape of the intake passage 2 is a perfect circle in order to compensate for the above-mentioned resin shrinkage. The evening storage section 18 also has no distortion, and its axis A 2 is parallel to the axis A 1 of the valve shaft.

In the intake air amount control device for an internal combustion engine according to the first embodiment of the present invention configured as described above, the stator 10 of the motor 6 is integrated with the throttle body housing 16 by insert molding. ing. Therefore, the housing 16 which does not require rigidity for mounting the motor can be formed of synthetic resin. In addition, the housing was molded with a mold whose shape and dimensions were corrected to allow for deformation, and by reducing the thickness near the intake passage and devising the position of the reinforcing ribs, the dimensions of the housing were refined. The degree has improved. The controllability of the engine speed can be improved, and the number of parts can be reduced and the weight can be reduced. Also, the drive shaft 8 of the motor 6 and the valve shaft 3 of the throttle body are arranged in parallel, and the sensor 22 is housed near the joint with the reduction mechanism of the valve shaft 3, so that the axial dimension can be shortened. This is effective in obtaining an intake amount control device for an internal combustion engine with good mountability. Further, the mounting holes of the bearings 19 supporting the valve shaft 3 and the mounting holes of the bearings 20 and 21 supporting the drive shaft 8 of the motor 6 are formed at the same time. Since the hole between holes can be made with high precision by molding with the corrected mold, the gearing of the reduction mechanism is improved, the gear noise is reduced, and the rotational position accuracy of the throttle valve 4 is improved. Can be possible. The connectors 23 and 23 may be separated from the connectors for the motor 6 and the sensor 22 and formed integrally with the housing 16 without being consolidated depending on the wiring. Embodiment 2

FIG. 2 is a partial sectional view of an intake air amount control device for an internal combustion engine according to a second embodiment of the present invention. This embodiment is different from the first embodiment in that a yoke 26 and a bracket Using a DC motor, which is a completed product with 27, and insert-molding it into the housing 16 as in the first embodiment, the housing 16 can be made of synthetic resin. The connector 28 for the motor 25 and the connector 30 for the sensor 22 are integrally formed on the cover 28 that covers the drive unit of the valve shaft 3 by the motor 25. Are different.

With this configuration, a standard mode motor can be used without specializing the mode for driving the throttle valve, and the degree of freedom in the arrangement of the connectors is increased. Improved controllability of engine speed, reduced number of parts, reduced weight, improved mounting characteristics by shortening the axial dimension, reduced gear noise by increasing the precision of the mounting hole pitch of the valve shaft 3 and motor 25, An intake air amount control device for an internal combustion engine having an effect of improving the rotational position accuracy of the throttle valve 4 and the like can be obtained. In addition, the motor and sensor connectors are separated into a housing and a cover, and are integrally formed therewith. You can also. Industrial applicability

As described above, the motor and the motor are insert-molded and integrated by the throttle body housing, the drive shaft of the motor and the valve shaft of the throttle body are arranged in parallel, and the sensor is connected to the valve. Since the housing is provided at the joint of the shaft and the speed reducer, the housing that does not require rigidity for assembling the motor is made of synthetic resin, so that the number of parts and the weight can be reduced.

In addition, the housing was molded using a mold whose shape and dimensions were corrected to allow for deformation during molding of the synthetic resin, or by eliminating the flesh for one hour near the intake passage and devising the position of reinforcing ribs. The change in dimensions due to shrinkage during resin cooling can be reduced, and the roundness of the bore of the intake passage inside the intake control section, the dimensions and the dimensional accuracy of the reduction gear section are improved, and the desired engine idle speed is achieved. Control and good reduction gear engagement, improving throttle opening controllability ・ Improving gear abrasion resistance ・ Gear noise can be reduced, and seal failure due to improved cover mounting surface dimensional accuracy Thus, it is possible to obtain an excellent intake air amount control device for an internal combustion engine such that the axial dimension can be reduced and the mountability is improved.

Claims

The scope of the claims

1. A housing made of a synthetic resin forming an intake passage of an internal combustion engine therein, a valve shaft rotatably provided in the intake passage of the housing, and an air flow amount of the intake passage attached to the valve shaft. A throttle valve to be controlled; a motor formed by insert molding in the housing, which drives the valve shaft via a speed reduction mechanism; and a motor provided near a joint between the valve shaft and the speed reduction mechanism. An intake air amount control device for an internal combustion engine, comprising: a sensor for detecting a rotation angle.

2. In view of the change in dimensions of places where precision is required, such as the roundness of the intake passage due to shrinkage during resin cooling and the mounting pitch of the drive shaft and valve shaft due to shrinkage during resin cooling, The product is manufactured in a mold with resin shrinkage compensation for shape and Z or dimensions.

2. The intake air amount control device for an internal combustion engine according to 1.

3. In the synthetic resin housing, there is no wall between the intake passage and the motor, which requires precision such as roundness and passage diameter, to reduce dimensional changes due to shrinkage during resin cooling. 3. The intake air amount control device for an internal combustion engine according to claim 1, wherein

4. In a synthetic resin housing, in order to eliminate the flesh between the vicinity of the intake passage and the motor that requires accuracy such as roundness and / or passage diameter, and to secure the strength of the housing. 3. The intake air amount control device for an internal combustion engine according to claim 1, wherein a reinforcing rib is provided at a position distant from the intake passage to reduce a dimensional change due to shrinkage during resin cooling.

5. The intake air amount control device for an internal combustion engine according to any one of claims 1 to 4, wherein the drive shaft and the valve shaft of the motor are arranged in parallel with each other.

6. The intake air amount control device for an internal combustion engine according to claim 1, wherein the motor is a DC motor or a DC brushless motor.

7. The intake air amount control device for an internal combustion engine according to claim 1, wherein the external outlet connector of the motor and the external outlet connector of the sensor are formed integrally with the housing.

8. The internal combustion engine according to any one of claims 1 to 5, characterized in that the external outlet connector of the motor and the external outlet connector of the sensor are integrally formed with a cover that covers an end surface of the housing. Engine air intake control device.

9. The connector according to any one of claims 1 to 5, wherein one of the external outlet connector of the motor and the external outlet connector of the sensor is integrally formed with the housing and the other is integrally formed with the cover. Air intake control device for internal combustion engine.

10. The intake air amount control for an internal combustion engine according to claim 7 or 8, wherein the external outlet connector of the motor and the external outlet connector of the sensor are integrally formed and molded. apparatus.