This paper introduces a new design for the synchromesh gear boxes, which serves dual purpose of economizing the production cost and time of the gears manufacturing and enhancing the shift experience by reducing the shift effort.
This is achieved by making changes in the “Entry chamfers” which are the angles placed on the shift sleeve and gear dog teeth, and the “Back Taper Angle” also placed on the shift sleeve and gear dog teeth. In the new design the “Entry chamfer angles” is reduced from 120° (in the existing design) to 90° and is made “Un-symmetric” from “Symmetric”. This help in reducing the shift effort, hence enhancing the shift experience by making it smooth.
Another change is the “Back Taper Angle”, which is eliminated from the sleeve and the gear dog teeth and is repositioned on the hub, keeping all other important design parameters like strut / insert design, gear cone angle, gear cone finish, number of cones, cone friction material the same.
The new design ensures that the change in back taper angle position does not compromise its function of avoiding the “Gear jump out”. As per existing design for making the back taper angle on the sleeve and gear dog teeth special machining operations are required which increase the production cost and time. But according in new design for making the same angle (back taper angle) on the hub, only simple machining operations are enough. There is no need of any special machining operation, so this helps in reducing the production cost and time in making gears.