Planetary gear transmission systems or components – With means to vary drive ratio or disconnect drive – Ratio shift initiated by reverse rotation of input shaft
Reexamination Certificate
2000-01-13
2001-04-03
Estremsky, Sherry (Department: 3681)
Planetary gear transmission systems or components
With means to vary drive ratio or disconnect drive
Ratio shift initiated by reverse rotation of input shaft
C475S292000, C475S297000
Reexamination Certificate
active
06210300
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to a one-way clutch for use in parallel with a friction clutch in a planetary transmission. More specifically, the present invention relates to a reversible one-way clutch for use in parallel with a friction clutch to drive the low and reverse gears in a planetary transmission.
BACKGROUND OF THE INVENTION
In current transmission housings, there are a variety of ways to drive the low and reverse gears in a planetary transmission. These current systems utilize conventional designs which yield high cost and high parasitic losses.
Many current systems include a conventional low/reverse multifriction plate clutch pack positioned in parallel with a one-way clutch to ground a carrier of a planetary gear set to a transmission housing. These systems that utilize multi-pack clutches are inefficient and result in high parasitic losses. These prior systems also have high torque requirements, which results in relatively high cost.
Other current systems utilize a double-wrapped band in parallel with a one-way clutch to ground a carrier of a planetary gear set to a transmission housing. These systems that a utilize double-wrapped band require a relatively large amount of space to be implemented and therefore consume a large amount of space in the transmission housing. These systems that utilize double-wrapped bands require a relatively large amount of radial space to be implemented and therefore consume a large amount of space in the transmission housing. Moreover, because these prior systems with double-wrapped bands allow for slippage, which also results in inefficiency and high parasitic losses, they also have a high torque requirement, which makes them relatively expensive to manufacture and use.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a system for driving a transmission in low and reverse gears that provides lower cost and lower parasitic losses than conventional systems.
It is a further object of the present invention to provide a low/reverse gear system that takes up significantly less space in a transmission housing than current low/reverse gear systems.
It is a still further object of the present invention to provide a low/reverse gear system that can be easily retrofitted to existing transmissions to improve their efficiency at minimal cost and without taking up additional space.
In accordance with the above objects of the present invention, an improved system for driving a planetary transmission in reverse and low gear is provided. The planetary transmission is in communication with an input shaft to provide rotation thereto. The rotation from the input shaft is transferred to an input planetary assembly, including a sun gear, a pinion gear, a ring gear, and a carrier assembly. A reverse clutch is included which is in rotational communication with the input planetary assembly. To drive the planetary transmission in reverse, the reverse clutch, comprising a friction pack, is caused to spin at engine speed. This reverse clutch is then brought into engagement with the sun gear, which is in communication with an output shaft, to drive the transmission in reverse gear.
A low gear clutch is included which is in rotational communication with the input planetary assembly to drive the transmission in low gear. To drive the planetary transmission in low gear, the input planetary assembly is connected to an output planetary assembly, including a sun gear, an output pinion gear, an output ring gear, and an output carrier assembly. The low gear clutch drives the input ring gear, while the output carrier assembly is fixed. The output ring gear is thus rotating in a direction to drive the transmission in low gear. The output ring gear is in rotational communication with the output shaft. The reverse and low gear clutches are in communication with a reversible one-way clutch which is engaged by the appropriate clutch as required, depending upon in which gear the transmission is to be driven. An actuator is in communication with the reversible one-way clutch to bias the reversible clutch in the appropriate direction to assist in driving the transmission in the appropriate gear.
The reversible one-way clutch includes an outer race and an inner race. A clammed surface is located on either the outer race inner peripheral surface or the inner race outer peripheral surface. A plurality of cam engaging surface members are positioned between the outer race inner peripheral surface and the inner race outer peripheral surface. A biasing plate is in communication with the reversible one-way clutch to bias the reversible one-way clutch based on the actuator to allow either the low or reverse Clutch to drive the planetary transmission.
These and other features and advantages of the present invention will become apparent from the following description of the invention, when viewed in accordance with the accompanying drawings and appended claims.
REFERENCES:
patent: 5135444 (1992-08-01), Hattori
patent: 2096251 (1982-10-01), None
patent: 61-074940 (1986-04-01), None
Braford Thomas
Costin Daniel P.
Artz & Artz P.C.
Borg-Warner Inc.
Dziegielewski Greg
Estremsky Sherry
Waddell Tisha D.
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