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A hydraulic pump with an unloading function which comprises a pump body, a spring chamber formed in the pump body and communicating with a fluid reservoir, a pump chamber formed in the pump body and communicating with the spring chamber and an accumulator through a suction valve and a delivery valve

A hydraulic pump with an unloading function which comprises a pump body, a spring chamber formed in the pump body and communicating with a fluid reservoir, a pump chamber formed in the pump body and communicating with the spring chamber and an accumulator through a suction valve and a delivery valve, respectively. An operation chamber is also formed in the pump body and accommodates a drive member such as a pump drive shaft. A plunger slidably extending through a first partition between the spring chamber and the pump chamber, and a tappet having a smaller diameter than that of the plunger and slidably extends through a second partition between the pump chamber and the operation chamber to abut against the plunger. A spring is accommodated in the spring chamber and is adapted to apply a predetermined resilient force to the plunger to bias it toward the tappet.

대표청구항 ▼

A hydraulic pump comprising a pump body including first and second partitions dividing said pump body into a spring chamber, a pump chamber and an operation chamber, said first partition being between said spring chamber and said pump chamber, said second partition being between said pump chamber an

A hydraulic pump comprising a pump body including first and second partitions dividing said pump body into a spring chamber, a pump chamber and an operation chamber, said first partition being between said spring chamber and said pump chamber, said second partition being between said pump chamber and operation chamber, said spring chamber having a fluid inlet, suction valve means connecting said pump chamber and spring chamber for providing communication therebetween when said pump chamber is at a reduced pressure, delivery valve means connected to said pump chamber for delivering fluid therefrom when fluid in said pump chamber is at elevated pressure, a drive member in said operation chamber, a tappet slidably engaged in said second partition and driven by said drive member, a plunger slidably engaged in said first partition and disengagably contacted by said tappet, said plunger and tappet being operative in said pump chamber to increase and decrease the pressure of the fluid therein, said tappet having a smaller diameter than said plunger, and spring means in said spring chamber acting on said plunger for resiliently biasing the same against said tappet.