Improvements in or relating to dual-clutch transmissions

Abstract

A dual-clutch transmission (10), for a vehicle, comprises an odd gears clutch (11) and an associated odd gears shaft (12) supporting at least two odd-numbered rotary gears (13, 14, 16, 17), the odd gears clutch (11) being for transmitting rotary input drive via a 5 selected one of the odd-numbered rotary gears (13, 14, 16, 17) to a driven rotary shaft (18); an even gears clutch (19) and an associated even gears shaft (21) supporting at least two even-numbered rotary gears (22, 23, 24, 26), the even gears clutch (13) being for transmitting rotary input drive via a selected one of the even-numbered rotary gears (22, 23, 24, 26) to the driven rotary shaft (18). The driven rotary shaft (18) is selectively 10 connectable to one respective said odd- or even-numbered gear (13, 14, 16, 17, 22, 23,24, 26) at a time and the odd and even gears clutches (11, 19) are arranged to transmit drive on a mutually exclusive basis. The dual-clutch transmission (10) includes at least first and second rangeselection gears (27, 28) that are mutually exclusively releasably engageable to transfer drive from the driven rotary shaft (18) to an output shaft (20) so as selectively to permit selection of at least a first range transmission ratio or a second range transmission ratio between at least one said selected even or odd rotary gear (13, 14, 16, 17, 22, 23, 24, 26) and the output shaft (20) wherebyto permit selection of a relatively low output ratio range or a first higher output ratio range that is higher than the relatively low output ratio range. The dual-clutch transmission (10) further includes at least a first bypass drive line (31) including at least two mutually engaged bypass rotary gears (32, 33, 34, 36) and a bypass clutch (37) for selectively effecting driving engagement of at least two mutually engaged bypass rotary gears (32, 33, 34, 36) with the output shaft (20), the at least two mutually engaged bypass rotary gears (32, 33, 34, 36) when the bypass clutch (37) is engagedgiving rise to a first intermediate 25 transmission ratio that is intermediate the highest gear ratio of the relatively low output ratio range and the lowest gear ratio of the first higher output ratio range.

Description

technical field [0001] The invention relates to a dual clutch transmission (DCT) for a vehicle. Background technique [0002] Like all variable vehicle transmissions, a DCT converts the rotary drive input from the engine crankshaft into a rotary drive output that feeds, for example, a differential or other final drive assembly, where the gear ratio varies between the rotary input and the rotary output and has the ability to select the prevailing (prevailing) gear ratio. [0003] The DCT was originally developed for racing cars, ultra-high performance supercars and some high performance motorcycles. DCTs are required in such applications, partly because DCTs can be easily configured as fully automatic or semi-automatic transmissions (where the driver of the vehicle can implement sequential shifts, for example by using steering wheel-mounted shift paddles or shifter buttons). gear), while providing very fast ratio changeover times. [0004] A DCT is characterized by the exi...

AI Technical Summary

Problems solved by technology

[0018] Due to the need to accelerate the entire vehicle mass and several large rotating components after a range shift that may take a second or more to adversely affect the economy

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