Air flow rate control apparatus

Abstract

A throttle control apparatus for an engine on a vehicle is provided, in which the number of component parts in the position detection means and the driven means is reduced to improve the accuracy in its position control and at the same time an integrated wiring is achieved and connectors are aggregated. The position detection means for detecting the position of a control valve, the driven means for controlling the position of the control valve, the means for processing control signals, an output from the position control means for controlling the position of the control valve are disposed within a sealed space defined by a body supporting a control valve shaft, and a cover. Based on the fact that the number of component parts of the position detection means may be reduced, the mechanical hysteresis and electrical hysteresis may also be reduced to improve the accuracy in controlling the control valve position, and it is possible to aggregate the connectors.

1. An air flow rate control apparatus for controlling an amount of air to be taken into an engine, comprising:
 a control valve disposed within an air flow passage through which an air flows;   a body defining a portion of the air flow passage and rotatably accommodating said control valve;   a cover attached to said body;   a motor driven means for driving said control valve to a predetermined opening degree;   a switching means for selectively disconnecting said driven means from said control valve;   a detector for detecting a rotational position of a valve shaft to which said control valve is mounted as an opening degree of said control valve said detector disposed at an end portion of said valve shaft opposite to said motor driven means; and   a controller for processing a controlled variable of an opening degree of said control valve in accordance with a detection signal from the detector and outputting to said driven means a command signal corresponding to said controlled variable; and   an interface portion allowing an electrical data exchange among said detector, said driven means and said controller, and/or an electrical data exchange between these components and the outside of said apparatus through said interface portion, said interface portion disposed at the same side of said valve shaft as said detector is.   
     
     
       2. A motor driven throttle valve system comprising:
 a throttle body in which a throttle valve is mounted;   a recess portion provided adjacent said throttle valve for housing therein a motor for driving said throttle valve; and   a through hole for communicating said recess portion the outside thereof, through which an electric wire extends from said motor to the outside.   
     
     
       3. A motor driven throttle valve system comprising:
 a throttle body with an air intake passage;   a throttle valve element disposed in said air intake passage for changing an effective cross sectional area of said passage   a throttle shaft rotatably mounted in said throttle body for swinging said throttle valve element;   a motor for driving said throttle shaft through gear means provided on one end portion of said throttle shaft;   a position sensor provided on the other end portion of said throttle shaft for detecting a rotational displacement of said shaft;   a recess portion provided in said throttle body adjacent said throttle valve element for housing therein a motor for driving said throttle valve;   a through hole for communicating said recess portion with the outside thereof, through which an electric wire extends from said motor to the outside;   a cover member attached to said throttle body for covering said position sensor, through which electric wires from said motor and said position sensor extend out of the system.   
     
     
       4. A motor driven throttle valve system comprising:
 a body provided therein with an air intake passage;   a shaft rotatably mounted in said body;   a throttle valve element fixedly mounted to said shaft for changing an effective cross sectional area of said passage in accordance with a swing of said shaft;   a cover attached to said body to define therebetween a space;   a sensor disposed within said space for detecting an angular displacement of said shaft;   a motor mounted to said body;   a mechanism for transmitting a rotational torque from said motor to said shaft; and   a connector mounted to said cover, said connector including an output terminal of said sensor and an input terminal of said motor means.   
     
     
       5. A motor driven throttle valve system according to  claim 1 , further comprising a lost motion spring mechanism for applying a rotational force against said shaft so as to characterize a transmission characteristic of a torque to be transmitted from said motor to said shaft through said torque transmission mechanism, said spring mechanism being disposed within said space. 
     
     
       6. A motor driven throttle valve system according to  claim 1 , wherein said means and said torque transmission mechanism are provided on opposite end portions of said shaft. 
     
     
       7. A motor driven throttle valve system according to  claim 6 , further comprising a lost motion spring mechanism for applying a rotational force against said shaft so as to characterize a transmission characteristic of a torque to be transmitted from said motor to said shaft through said torque transmission mechanism, said spring mechanism being disposed within said space. 
     
     
       8. An air flow rate control apparatus for controlling an amount of air to be taken into an engine, comprising:
 a control valve disposed within an air flow passage through which said air flows;   a body defining a portion of said air flow passage and rotatably accommodating said control valve;   a cover attached to said body;   a motor driven means for driving said control valve to a predetermined opening degree;   a detector for detecting a rotational position of a valve shaft to which said control valve is mounted as an opening degree of said control valve, said detector disposed at an end portion of said valve shaft opposite to said motor driven means; and   an interface portion for allowing an electrical data exchange between said detector and said driven means, and the outside of said apparatus through said interface portion, said interface portion disposed at the same side of said valve shaft as said detector is.   
     
     
       9. An apparatus according to  claim 8 , wherein an opening for allowing a communication between said space and the outside thereof is provided. 
     
     
       10. An apparatus according to  claim 8 , wherein said interface portion is provided on said cover. 
     
     
       11. An apparatus according to  claim 8 , wherein said driven means further comprises a switching means capable of selectively disconnecting said driven means from said control valve. 
     
     
       12. An apparatus according to  claim 11 , wherein an opening for allowing a communication between said space and the outside thereof is provided. 
     
     
       13. An apparatus according to  claim 11 , wherein said interface portion is provided on said cover. 
     
     
       14. A throttle valve system comprising:
 a throttle body with an air intake passage;   a throttle valve element disposed in said air intake passage for changing an effective cross sectional area of said passage;   a throttle valve shaft rotatably mounted on a bearing in said throttle body for swinging said throttle valve element;   a first metal bushing press-fitted at an outer periphery thereof to a recess portion of said throttle body and coaxially said throttle shaft; and   a throttle position sensor, said sensor including:
 a sensor element; 
 a second metal bushing fitted to said first metal bushing to support said sensor element; 
 a slider rotatably mounted to said second metal bushing; 
 a transmitting member provided between said throttle valve shaft and said slider thereby said slider is rotated by said throttle valve shaft; 
 a conductive element provided on the surface of said throttle position sensor element; and 
 a slider element mounted on said slider for providing electrical contact to said conductive element. 
   
     
     
       15. A system according to  claim 14 , wherein a sealing rubber ring is provided between an inner periphery of said first metal bushing and an outer periphery of said throttle valve shaft. 
     
     
       16. A system according to  claim 14 , wherein said slider is axially urged by means of a spring, thereby being in contact with said conductive element at a predetermined contact pressure. 
     
     
       17. A motor driven throttle valve system comprising:
 a throttle body with an air intake passage;   a throttle valve element disposed in said air intake passage for changing an effective cross sectional area of said passage;   a throttle valve shaft rotatably mounted in said throttle body for swinging said throttle valve element;   a motor for driving said throttle valve shaft through gear means provided on one end portion of said throttle valve shaft;   a throttle position sensor provided on the other end portion of said throttle valve shaft for detecting a rotational displacement of said throttle valve shaft;   a recess portion provided in said throttle body adjacent said throttle valve element for housing therein said motor;   a microcomputer electrically connected to said throttle position sensor and said motor; and   a cover member attached to said throttle body for covering said throttle position sensor and said microcomputer.   
     
     
       18. A system according to  claim 17 , said throttle position sensor is covered by a control unit attached to said throttle body, and wherein said microcomputer is attached to said control unit, and wherein said control unit is covered by said cover member. 
     
     
       19. A system according to  claim 17 , wherein said microcomputer is electrically connected to an accelerator position sensor. 
     
     
       20. A system according to  claim 19 , wherein said accelerator position sensor is attached to said cover. 
     
     
       21. An airflow rate control apparatus of an engine comprising:
 a throttle valve for controlling an airflow rate of the engine;   a throttle shaft rotatably supporting the throttle valve with respect to a throttle body;   a motor for the throttle shaft;   a speed reduction gear mechanism for transmitting rotation of the motor to said gear;   a ball bearing attached to the throttle body to support the throttle shaft on the speed reduction mechanism side thereof;   a gear cover attached to the throttle body to cover the speed reduction gear mechanism; and   a sealing mechanism provided between the throttle shaft and the throttle body so as to achieve a seal between the speed reduction mechanism and the ball bearing.   
     
     
       22. An apparatus according to claim 21, wherein said gear cover is fixed to the throttle body, and a sealing member is interposed therebetween. 
     
     
       23. An apparatus according to claim 21, wherein a stopper is formed in said gear cover for restricting a thrust position of an intermediate gear of the speed reduction gear. 
     
     
       24. An apparatus according to claim 21, wherein
 said gear attached to the throttle shaft has a shape which is lacking a part thereof in a circumferential direction, and   the throttle body is provided with a stopper for receiving a lacked end surface of the lack portion of the gear attached to the throttle shaft.   
     
     
       25. An apparatus according to claim 24, wherein said stopper is fixed to an attachment seat of the throttle body. 
     
     
       26. An apparatus according to claim 25, wherein said stopper is constituted by an adjustable screw. 
     
     
       27. An apparatus according to claim 21, further comprising a bearing bore formed in the throttle body, through which bore said throttle shaft extends; a cover attached to the throttle body to cover an end of the throttle shaft; and a throttle sensor for detecting rotation of the throttle shaft; wherein said throttle sensor is provided with a sliding resistor and a brush. 
     
     
       28. An apparatus according to claim 27, wherein said brush is rotated with the throttle shaft. 
     
     
       29. An apparatus according to claim 27, wherein
 one end of the throttle shaft on a side on which the throttle sensor is provided is supported by a metal bearing provided in the throttle body, and   said sealing mechanism is provided in a portion of the throttle shaft, which portion protrudes from the metal bearing.   
     
     
       30. An apparatus according to claim 29, wherein said sealing mechanism comprises a metal bushing pressed into a recess portion of the throttle body around the protruding portion of the throttle shaft from the metal bearing, and a rubber seal installed between the metal bush and a periphery of the throttle shaft. 
     
     
       31. An apparatus according to claim 27, wherein said throttle sensor comprises a resistor circuit board fixed to the throttle body, and a brush fixed to the throttle shaft so as to slide on a resistor body of the resistor circuit board. 
     
     
       32. An apparatus according to claim 31, wherein
 a metal bushing having a sleeve is pressed into a recess portion of the throttle body, the recess portion being located around a portion of the throttle shaft protruding from the bearing bore;   another metal bushing is rotatably supported by the sleeve of the metal bushing; and   said throttle sensor comprises a brush attached to said other metal bushing.   
     
     
       33. An airflow rate control apparatus of an engine comprising:
 a throttle valve for controlling an airflow rate of the engine;   a throttle shaft rotatably supporting the throttle valve with respect to a throttle body;   a gear fixed to one end of the throttle shaft;   a motor fixed to the throttle body;   a speed reduction gear mechanism for transmitting rotation of the motor to the gear;   a ball bearing attached to the throttle body to support the throttle shaft on the speed reduction mechanism side thereof; and   a metal bearing attached to the throttle body to support the throttle shaft on the opposite side to the speed reduction gear mechanism side thereof.   
     
     
       34. An apparatus according to claim 33, further comprising a bearing bore formed in the throttle body, through which bore said throttle shaft extends; and a cover attached to the throttle body to cover an end of the throttle shaft; wherein said throttle sensor is provided with a sliding resistor and a brush. 
     
     
       35. An apparatus according to claim 34, wherein said brush is rotated with the throttle shaft. 
     
     
       36. An apparatus according to claim 33, further comprising a sealing mechanism provided between the throttle shaft and the throttle body to achieve a seal between the speed reduction mechanism and the ball bearing. 
     
     
       37. An apparatus according to claim 36, further comprising a sealing mechanism provided between the throttle body and a periphery of the throttle shaft protruding from the metal housing.