The paper is dedicated to design of a new dog-clutch gearshift mechanism for passenger car gearboxes with external synchronization. There are two main targets of presented work:
Replace the standard synchronizer with cheap and compact shift device, which will keep the internal architecture of classical manual transmission.
Keep all the other important functions of synchronizer:
minimal circular backlash to avoid clash during change of sense of the torque flow,
prevent unwanted disengagement,
guarantee the shift anytime,
determine neutral position (preferably).
Czech Technical University in Prague is for several years active in the field of design and testing of shift mechanisms, as well as in design of new shift clutches. The currently presented clutch is 3rd generation of inventions of dog clutch systems. All clutches were fabricated as prototype and tested. All designs will be briefly described in the paper.
To observe the real life function the prototype was assembled into the passenger car gearbox between the IIIrd and IVth speed. The transmission was equipped with external synchronization device. With help of external synchronization device the different relative speeds between the free rotating wheel and shaft can be preset. The impact of speed difference on shift smoothness can be evaluated with help of vibration measurement. The results were compared with the same gearbox equipped with classical synchronizer.
The currently presented clutch minimizes the number of pieces, shortens the length, and lowers the weight and costs of shift clutch with respect to the standard synchronizer.