Valves and valve actuation – Biased trip – Electrical trip actuation
Reexamination Certificate
2000-04-25
2001-07-03
Kaufman, Joseph A. (Department: 3754)
Valves and valve actuation
Biased trip
Electrical trip actuation
C251S129110
Reexamination Certificate
active
06254058
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
MICROFICHE APPENDIX
Not Applicable
BACKGROUND OF THE INVENTION
The present invention relates to servomotor operated rotary valves and particularly valves of the type intended for on-board motor vehicle application such, as for example, valves employed for diverting flow of air as between plural passages in an engine inlet manifold.
Currently some automotive engines employ different length passages in the inlet manifold for producing different flow characteristics in different regimes of the engine speed/load envelope and a motorized diverter valve is employed for switching air flow from one set of passages to another as the flow requirements of the engine are increased with increasing load and/or speed. The motorized diverter valve for such an application must, of necessity, be small in volume and have a minimal current draw, yet provide fast response in order that the diverter valve can adequately respond to operator throttle input demands. In a typical passenger car or light truck application the engine electronic computer for generating an electrical control signal to drive the diverter valve motor.
Furthermore, it is required to have a high degree of accuracy in positioning the valve during rotation in order to achieve the desired precise amount of flow diversion for engine inlet air in order that the engine operation may be optimized without adversely effecting the combustion and resultant emissions. The electronic engine computer also controls the electrically operated fuel injectors with an algorithm which includes throttle position as an input.
Thus, it has been desired to have a small low current motor for an engine manifold diverter valve capable of operating on a typical low voltage direct current vehicle power supply and which can provide desired accuracy of valve positioning, quick response and sufficient torque to move the valve readily to the desired operating position. Heretofore, this has been achieved by using a gear reduction train with a numerically high overall ratio of a motor input shaft rotation to output valve shaft rotation.
However, it has also been a requirement that such a rotary diverter valve for engine air inlet manifold applications have a provision for return to an initial rotational position in the event of servomotor failure or loss of electrical power once the valve has been rotated from the initial position to an operational air diverting position. However, where a high numerical ratio of speed reduction has been provided between the motor input shaft and the valve shaft, it has been found virtually impossible to provide a spring return for the valve inasmuch as the return spring must have adequate stored energy from winding to back drive the motor shaft through the mechanical disadvantage of the gear train when driven by applying the spring torque to the valve shaft.
Thus, it has long been desired to provide a way or means of spring returning a motor driven rotary diverter valve drivers by a small low current having a high numerical gear reduction in a manner which does not require a heavy return spring resulting in additional drive motor loading in order to overcome the torque of the return spring.
The motorized diverter valve for such engine applications must also be reliable and relatively low in manufacturing cost so as not to render the desired engine control prohibitively costly for high-volume, mass-produced vehicle engines.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a servomotor operated rotary diverter valve having a small subfractional horsepower low voltage drive motor driving the rotary valve through a gear train having a numerically high reduction for providing accurate positioning of the diverter valve and has provision for spring returning of the diverter valve to an initial position in the event of motor failure during operation of the valve.
The servomotor driven rotary diverter valve of the present invention has particular suitability for an engine air inlet manifold diverter application and provides a relatively high degree of positional accuracy for the diverter valve, relatively low manufacturing cost, reliability and compact design.
The servomotor driven valve of the present invention utilizes a differential planetary gear train with the servomotor driving the sun gear and the torsion return spring biased directly to the planetary carrier for providing return spring drive to the carrier for returning the valve to the initial position in the event of a motor failure during operation.
The servomotor driven diverter valve of the present invention utilizes a planetary drive having the motor driving a sun gear engaging a first set of teeth on the carrier mounted planetary gears, which first set of teeth also engage an output ring gear connected to the valve shaft. A second set of teeth are provided coaxially mounted on each of the planetary gears and have a greater pitch diameter than the first set of teeth which second set of teeth engage a fixed ring gear. The arrangement of the differential planetary gears enables the motor to wind a low spring rate torsion spring during motor operation. The return spring is wound by rotation of the planetary carrier to store enough energy to rotate the carrier if the motor operation ceases; and, the carrier is then able to drive the output through the second stage reduction to return the valve to the initial position. The gear reduction between the motor driven sun gear and the first stage planetary reduction is sufficient to enable a low current subfractional horsepower motor to drive the planet carrier and wind the return spring.
The present invention thus provides a solution to the above-described problem of providing a high degree of accuracy of positioning of a rotary diverter valve from a small low current low voltage drive motor with a numerically high ratio of input shaft speed reduction in a compact configuration and yet provides for spring return of the rotary valve member in the event of motor failure during operation without the use of a heavy return spring and increased motor power requirement.
REFERENCES:
patent: 5117784 (1992-06-01), Schechter et al.
patent: 5182498 (1993-01-01), Stuhr
patent: 5230411 (1993-07-01), Nishida et al.
patent: 5634842 (1997-06-01), Becker
patent: 5988319 (1999-11-01), Hudson et al.
Bonderer D H
Eaton Corporation
Johnston Roger A.
Kaufman Joseph A.
LandOfFree
Spring returning a rotary valve with a differential... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Spring returning a rotary valve with a differential..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spring returning a rotary valve with a differential... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2543727