| 摘要 |
PROBLEM TO BE SOLVED: To effectively reduce gear chattering noise of a gear train by forming, on a cam, a protrude for canceling a torque in a positive direction applied on a camshaft by pushing a plunger by a return spring, in a pump wherein a plunger is protruded up against the return spring by the cam and fuel is forcibly supplied. SOLUTION: In a gear train for driving a camshaft 29 of a fuel injection pump, gear chattering noise is not generated since a working face of each gear 71 to 74 for forming the gear train is not changed in the case where the camshaft 29 is driven by a crankshaft 70 at all times. When rotating speed of the crankshaft 70 is fluctuated, rotating speed of the camshaft 29 is accelerated, the working face is inversed, and gear chattering noise is generated. For solving a speed difference between both the shafts 29 and 70, a protrude 78 is formed in an initial region of a part 77 of rising gradient in a cam 30. It is thus possible to effectively reduce gear chattering noise and noise in association with the gear chattering noise without exerting wrong effect on a fuel injection operation.
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