차량용 수동 변속기의 후진변속울림 방지장치에 대한 고찰

Varieties of reverse braking systems for manual transmission are investigated. Reverse braking system is different from synchronizer mechanism which is used for forward gears in automotive manual transmission. The purpose of reverse braking system of manual transmission is to eliminate clashing or grinding noise when shifting to reverse gear. In the constant mesh arrangement, reverse idler gear has to engage two other gears to complete torque flow when the vehicle is stationary while shifting to reverse, input shaft with the reverse pinion could still be spinning due to clutch disk inertia and this will create the clashing or grinding noise. The reverse braking system stops the rotation of the input shaft and prevents clashing noise. Clashing noise by reverse gear shifting strongly depends on driver’s behavior as described, e.g., enough spin down time, more over 3 sec, will seldom generate clashing noise even without reverse braking system. However the reverse brake will guarantee that at all times, the spinning input shaft is stopped even when shifting quickly to reverse. Characteristics of each reverse braking system is reviewed and tabulated for better understanding.