Machine element or mechanism – Gearing – Interchangeably locked
Patent
1993-07-02
1995-02-14
Bonck, Rodney H.
Machine element or mechanism
Gearing
Interchangeably locked
F16H 304
Patent
active
053884728
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a motor vehicle gearbox with an input shaft, a pair of counter-shafts, an output shaft and pairwise cooperating gear wheels on the input and counter-shafts and on the output and counter-shafts, at least one gear wheel in each pair of cooperating gear wheels being rotatably mounted and lockable on its shaft by means of engaging clutch means, the clutch means for locking cooperating gear wheels on the input and counter-shafts being friction clutches, the counter-shafts being coordinated with synchronizing means independent of the clutch means, by means of which synchronizing means the respective counter-shaft can be accelerated up to a certain engine speed determined by the selected gear.
BACKGROUND OF THE INVENTION
Double counter-shafts are used, on the one hand, in gearboxes in which it is desired, with a given length of gearbox, to obtain more gear ratios than what is practically possible in a conventional gearbox design with one counter-shaft, and, on the other hand, in so-called powershift gearboxes, i.e. gearboxes with double clutches, each cooperating with an individual counter-shaft. In such gearboxes the gear speeds are preselected and shifting is thereafter effected by disengaging one clutch and engaging the other clutch.
Various solutions are known for achieving a compact gearbox design of the powershift type with a large number of gear ratios. In one type which is known by SE 8700583-1 (corresponding to US-A-4,876,907) two concentric input shafts are used driving individual counter-shafts which can be engaged alternately with the aid of a pair of multiple disc clutches arranged in series outside the gearbox. Synchronization is achieved with the aid of a central synchronizing clutch on one of the counter-shafts. In another gearbox type with double counter-shafts, which is known by e.g. GB-A-2,110,324, a single input shaft drives simultaneously two gear wheels which, via individual clutches arranged inside the housing on the respective counter-shafts, can be locked to its shaft and establish a drive train between the input shaft and the output shaft via either counter-shaft. The synchronization is achieved with the aid of a two-part synchronizing device, which in this version is formed by a synchronizing clutch on either counter-shaft. In this gearbox, the torque is transmitted from the input shaft to the output shaft in all gear ratios Via a counter-shaft. The gearbox thus has no direct drive gear ratio.
OBJECT OF THE INVENTION
The purpose of the present invention is to provide a gearbox of the type described by way of introduction which combines the advantages of the known gearboxes as described above at the same time as individual disadvantages, such as excessive design length, due to placing the clutches in series outside the gearbox housing as compared to beside each other inside the housing, and the lack of a direct drive gear, are eliminated.
SUMMARY OF THE INVENTION
This is achieved according to the invention by virtue of the fact that the input shaft has a gear wheel rotatably mounted thereon, which engages a gear wheel on one of the counter-shafts and is lockable, on the one hand, by means of one of said friction clutches, to said input shaft and, on the other hand, relative to the output shaft by means of one of the other engaging clutch means. The gearbox according to the invention uses a single input shaft and friction clutches arranged in the housing on individual shafts, which provides a simple mounting of the input shaft and a short length of the transmission as a whole. By arranging these clutches on one of the counter-shafts and on the input shaft instead of on both counter-shafts, and also mounting a gear wheel which can be locked relative to the output shaft with the aid of a common engaging sleeve and relative to the input shaft with the aid of one of the friction clutches, there is obtained both direct drive in the highest gear speed and powershift into the highest gear.
BRIEF DESCRIPTION OF THE DRAWINGS
The
REFERENCES:
patent: 4685343 (1987-08-01), Ehrlinger et al.
patent: 4727764 (1988-03-01), Klaue
patent: 4831894 (1989-05-01), Braun
patent: 5079965 (1992-01-01), Leber et al.
patent: 5239887 (1993-08-01), Muller et al.
AB Volvo
Bonck Rodney H.
Wittels Daniel
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