PURPOSE: To enhance the maximum lift speed and allow high prescure injection by forming a sharp reduction part in which lift speed is sharply reduced in the front part of a second cam part, and a gradual reduction part in which the lift speed is constant or gradually reduced in the rear part.
CONSTITUTION: A plunger cam 7 rotates and reciprocates together with a cam 4 to pressurize the fuel in a fuel pressurizing chamber 8. The cam ridge 41 of the cam 4 consists of a lift part 41c from a rotating directional front end 41a to a top part 41b and a descending part 41e from the top part 41b to a rear end 41d, and the lift part 41c is formed of a first cam part 411 in which the lift speed is sharply increased at an angle α1, a second cam part 412 continued to its rear end A in which the lift speed is reduced, and a third cam part 413 continued to the rear end B in which the lift speed is sharply reduced at an angle α2. The second cam part 412 is formed of a sharp reduction part 414 with an angle α3, and a gradual reduction part 415 with an angle α4 and the maximum lift speed of the first cam part 411 is increased by the sharp reduction part 414. Thus, the cam 4 is used in a distributor type injection pump, whereby its injection pressure can be enhanced.
NAKAMURA HISASHI
KUNISHIMA AKIRA
YOSHIZU FUMITSUGU
