Dog Clutch Without Angular Backlash

Abstract

Dog clutches are simple and inexpensive mechanisms for shifting gears. However, their usage in automotive gearboxes was limited due to angular backlash in the engaged state and the resulting discomfort. Based on a thorough research of existing solutions, a new and unique design of a dog clutch without angular backlash was developed and later patented. The angular backlash is minimized due to the purely mechanical blocking mechanism. The new dog clutch is interchangeable with conventional gearshift mechanisms without additional modifications and requires an external synchronization system. The design of the new dog clutch with blocking mechanism is described in detail with a focus on the innovative parts – gearshift dogs and the blocking mechanism. Adaptation for sequential shifting was carried out and the clutch was complemented by a design and simulation program. Two prototypes of the clutch were manufactured in cooperation with an industrial partner and verified on the test bench inside a gearbox. These prototypes were tested for functionality, service life, and comfort during gearshift. The test bench had to be significantly modified and updated to make these tests possible. The verification was judged successful. The dog clutch with blocking mechanism is suitable for shifting gears in automotive gearboxes, in particular of hybrid and electric vehicles equipped with electric motor. It is able to eliminate some shortcomings of conventional dog clutches, as described in the research part.

Zubové spojky jsou jednoduché a levné mechanismy pro řazení převodových stupňů. Jejich použití v automobilových převodovkách však bylo omezeno úhlovou vůlí v zařazeném stavu a z toho plynoucím zhoršením jízdního komfortu. Na základě rešerše stávajících řešení byla vyvinuta a později patentována nová a unikátní konstrukce zubové spojky bez úhlové vůle. Vůle je minimalizována díky čistě mechanickému jisticímu mechanismu. Nová zubová spojka je zaměnitelná za konvenční mechanismy řazení bez dodatečných úprav a vyžaduje systém vnější synchronizace otáček.