Machine element or mechanism – Gearing – Interchangeably locked
Patent
1993-09-22
1995-05-23
Look, Edward K.
Machine element or mechanism
Gearing
Interchangeably locked
74360, F16H 308
Patent
active
054171253
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an automatic transmission for motor vehicles, comprising an input shaft driven by a torque converter, two counter shafts alternately driveable by the input shaft, an output element and gears grouped in pairs on the shafts for driving the output element from the input shaft via one or the other of the counter shafts, at least one gear in each gear pair co-operating between the input shaft and the respective countershaft being freely rotatably mounted on its associated shaft and being lockable to the shaft by means of a friction clutch.
2. Description of the Related Art
Automatic transmissions of this type, i.e. those provided with counter shafts, are simpler and less expensive to manufacture, especially for manufacturers already producing manual transmissions, than are the conventional type of automatic transmission using interconnected sets of planetary gears, wherein the sun gear and/or annulus and cage are locked or released with the aid of brakes and interleaved clutches. Transmissions with twin counter shafts can also be designed significantly shorter in the axial direction than transmissions based on planetary gearing, and this makes them particularly suited for use in front-wheel drive vehicles with transverse engines.
SUMMARY OF THE INVENTION
The purpose of the present invention is, starting from an automatic transmission with twin counter shafts, to provide a transmission which, while maintaining an optimally short length, can be designed to provide great freedom as regards selection of gear ratio at the same time as a single basic design for four forward gear ratios and one reverse gear ratio can be used without modification of the gear and clutch arrangement in both a four-speed transmission for front-wheel drive with a transverse engine and a five-speed transmission for rear-wheel drive with a longitudinally mounted engine.
This is achieved according to the invention by virtue of the fact that said counter shafts have at least one pair of gears, which are rotatably mounted and lockable to their respective shafts by a friction clutch and engage a common driving gear mounted on the input shaft, and at least two additional gears, which are freely rotatably mounted and lockable to their respective counter shafts by a friction clutch, said additional two gears engaging different driving gears on the input shaft.
The design according to the invention makes possible rational manufacture of automatic transmissions for both front-wheel drive and rear-wheel drive vehicles since most of the individual components in the transmissions can be common to both and be identically disposed in the transmission housing in both versions.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in more detail with reference to examples shown in the accompanying drawings, where
FIG. 1 shows a schematic end view of a transmission according to the invention for rear-wheel drive,
FIG. 2 shows a schematic longitudinal section along the line I--I in FIG. 1,
FIG. 3 shows a schematic end view of a transmission according to the invention for front-wheel drive and
FIG. 4 shows a schematic longitudinal section along the line III--III in FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The transmission shown in FIGS. 1 and 2 has a housing 1 with an input shaft 2 which is driven by an engine (not shown) via a conventional hydraulic torque converter 3. The input shaft 2 has a pair of driving gears 4 and 5 fixed to the shaft 2. Driving gear 4 is in engagement with a rotatably mounted gear 8 on a first countershaft 6 and driving gear 5 is in engagement with a rotatably mounted gear 9 on a second counter shaft 7. The gears 8 and 9 can be locked to their respective countershafts by means of first and second multidisk interleaf wet clutches 10 and 11 respectively.
The input shaft 2 has a further gear 12 non rotatably fixed to the shaft, said gear 12 engaging gear 13 rotatably mounted on countershaft 6 and gear 14 rotatably mounted o
REFERENCES:
patent: 2972899 (1961-02-01), Wiggerman
patent: 4375171 (1983-03-01), Morscheck
patent: 4579015 (1986-04-01), Fukui
patent: 4776227 (1988-10-01), Janiszewski
patent: 4960005 (1990-10-01), Kashiwase
AB Volvo
Look Edward K.
Sgantzos Mark
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