| 摘要 |
A machine for the manufacture of variable ratio racks such as are used in the steering gear of cars, the machine having a plurality of pairs of broaching blades and a holding fixture for holding at least one rack blank so that it can be indexed about a central point of the rack. The machine is arranged so that as either the broach blades are moved past the rack blank or the rack blank is moved past the broach blades pairs of corresponding teeth on each side of the center line are formed simultaneously, the rack blank being indexed to an angle to suit the angle of inclination of a pair of teeth about to be cut to the longitudinal axis of the rack. The machine produces a rack blank in which pairs of teeth of different form and different angular inclination are formed to a shape closely approximating the final shape of the teeth which is achieved by an additional step such as pressing or machining. |
