Cam shaft for fuel injection pump

A cam shaft having at least two cams, each cam driving a plunger of fuel injection pump provided for each cylinder of an internal combustion engine, the cam shaft having a longitudinal direction, comprising:

• a first cam formed on the cam shaft and having a first cam profile of nearly fan shape for lifting a first plunger, the first cam profile having a first lift increment segment, a first lift decrement segment and a first maximum lift maintenance segment connecting the first lift increment and decrement segments;
• and
• a second cam formed on the shaft and having a second cam profile of nearly fan shape symmetrical with the first cam with respect to a center of the cam shaft for lifting a second plunger, the second cam being spaced from the first cam in the longitudinal direction of the cam shaft, the second cam profile having a second lift increment segment, a second lift decrement segment and a second maximum lift maintenance segment connecting the second lift increment and decrement segments, the first lift increment segment overlapping the second lift decrement segment as viewed in the longitudinal direction of the cam shaft such that torque produced by the first lift increment segment is counterbalanced by the second lift decrement segment, and the first lift decrement segment overlapping the second lift increment segment as viewed in the longitudinal direction of the cam shaft such that torque produced by the second lift increment segment is counterbalanced by the first lift decrement segment.