초록 ▼

A pump system of the reciprocating piston type is described, which facilitates direct motor drive and cylinder sealing. A threaded middle potion of the piston is engaged by a nut connected to rotate with the rotor of an electric motor, in a manner that minimizes loading on the rotor by the use of a

A pump system of the reciprocating piston type is described, which facilitates direct motor drive and cylinder sealing. A threaded middle potion of the piston is engaged by a nut connected to rotate with the rotor of an electric motor, in a manner that minimizes loading on the rotor by the use of a coupling that transmits torque to the nut but permits it to shift axially and radially with respect to the rotor. The nut has a threaded hydrostatic bearing for engaging the threaded piston portion, with an oil-carrying groove in the nut being interrupted. A fluid emitting seal located at the entrance to each cylinder, can serve to center the piston within the cylinder, wash the piston, and to aid in sealing. The piston can have a long stroke to diameter ratio to minimize reciprocations and wear on valves at high pressures. The voltage applied to the motor can be reversed prior to the piston reaching the end of its stroke, to permit pressure on the piston to aid in reversing the motor.

대표청구항 ▼

A pump comprising: a cylinder having inlet and outlet means for receiving and allowing the exit of fluid; a piston having an end portion in said cylinder and a threaded portion; a motor having a stator and a rotor; nut means coupled to said rotor to rotate with it, and threadably engaged with said p

A pump comprising: a cylinder having inlet and outlet means for receiving and allowing the exit of fluid; a piston having an end portion in said cylinder and a threaded portion; a motor having a stator and a rotor; nut means coupled to said rotor to rotate with it, and threadably engaged with said piston threaded portion, said nut means including walls defining an internal thread, a channel extending in a helix along said walls, and pressured fluid feed means coupled to said channel to provide hydraulic fluid to said channel; said channel having a plurality of interruptions therealong forming barriers to the free flow of fluid between channel portions that lie on opposite sides of the barrier, and said feed means including a plurality of restricted feed conduits leading to different of said channel portions to supply fluid thereto.