Machine element or mechanism – Gearing – Interchangeably locked
Reexamination Certificate
1999-08-24
2001-06-12
Estremsky, Sherry (Department: 3681)
Machine element or mechanism
Gearing
Interchangeably locked
C074S329000, C074S331000, C074S333000
Reexamination Certificate
active
06244123
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention.
This invention relates to the field of manual transmissions for motor vehicles, especially to those in which gears are changed without disconnecting an engine from the transmission input.
2. Description of the Prior Art
U.S. Pat. No. 4,461,188 A1 disclosed a multiple-speed gearbox of 3-shaft design, especially for motor vehicles.
In the known multiple-speed gearboxes of three-shaft design, especially for motor vehicles, use is likewise made of a selectively switchable dual friction-disc clutch in order to drive a central input shaft and a concentric hollow input shaft, and a large number of gear pairs, which mesh with one another, are connected in a driving manner to their shafts via corresponding synchronizing clutches. The known multiple-speed gearbox is in this case constructed in such a way that both of the gearbox shafts to be designated layshafts or countershafts are designed as output drive shafts, which act on a final output drive gear via a corresponding output drive pinion in each case.
In the known multiple-speed gearbox, the gear pairs are arranged in such a way that essentially only the four forward speeds and one reverse speed, which are desired for a vehicle are provided.
SUMMARY OF THE INVENTION
The object of the invention is to provide a multiple-speed gearbox of three-shaft design, especially for motor vehicles, in which, by means of the strategic arrangement of the gear pairs in conjunction with their synchronizing clutches, a large number of gear steps having different ratios can be provided, from which, in an application in the motor vehicle, various sets of at least six forward speed steps and at least one reverse speed in each case are provided by means of selective switching of the double friction-disc clutch and the synchronizing clutches and, in their selection of the ratio, can be adapted to the internal combustion drive engine and its torque being used in each case.
This object is achieved according to the invention in a multiple-speed gearbox for motor vehicles that includes a first input shaft; a second hollow input shaft concentric with and surrounding the first input shaft; first and second mutually parallel countershafts substantially parallel to the input shafts[, the first countershaft having an output drive pinion driveably connectable to an output shaft; first and second selectively switchable friction clutches, the first clutch connected to the first input shaft, the second clutch connected to the second input shaft; pairs of meshing gears, each pair having a first member supported on one of the first and second input shafts and a second member supported on one of the first and second countershafts, each pair having a gear fixed to the shaft on which it is supported and a gear journalled on the shaft on which it is supported; synchronizers for driveably connecting the journalled gears to the shafts on which they are supported located, a first synchronizer located between two journalled gears supported on the first input shaft, a second synchronizer located between two journalled gears supported on the second input shaft, a third synchronizer located between two journalled gears supported on the first countershaft, a fourth synchronizer located between two journalled gears supported on the first countershaft; and the first input shaft connectable to the second input shaft by a synchronizer clutch.
REFERENCES:
patent: 4461188 (1984-07-01), Fisher
patent: 5458014 (1995-10-01), Thomas et al.
patent: 5609062 (1997-03-01), Reynolds
patent: 5761961 (1998-06-01), Krauss et al.
patent: 6023987 (2000-02-01), Forsyth
patent: 6044931 (2000-04-01), Reed, Jr. et al.
patent: 6050152 (2000-04-01), Alfredsson
Dahl Peter
Eggert Ulrich
Hegerath Andreas
Nett Hans Peter
Estremsky Sherry
Ford Global Technologies Inc.
Ford Global Technologies Inc.
Lewis Tisha D.
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