Rotary vane pump having enhanced cold start priming

A sliding vane rotary hydraulic pump comprising:

• a housing;
• a rotor mounted in the housing for rotation about an axis, having multiple vane slots adapted to receive a radially sliding vane therein;
• a cam surrounding said rotor, having multiple arcuate surfaces facing the vanes and adapted for contact thereby, said surfaces being spaced mutually around the rotor axis;
• a first pressure plate located at a first axial side of the rotor, having an inlet port and an outlet port spaced mutually around the rotor axis, having a first passage aligned with the radially inner end of the vane slots and extending angularly from the inlet port to the outlet port;
• and
• a second pressure plate located at a second axial side of the rotor, having an inlet port and an outlet port spaced mutually around the rotor axis and aligned with corresponding ports of the first pressure plate, the space between the cam, rotor, vanes and pressure plates defining pumping chambers whose size increases as distance of the arcuate surfaces from the rotor increases and decreases as distance of the arcuate surfaces from the rotor decreases, having a blind passage aligned with the radially inner end of the vane slots and extending angularly across the outlet port, and having a second passage aligned with the radially inner end of the vane slots, extending angularly across the inlet port and communicating with the outlet port.

A sliding vane rotary hydraulic pump comprising:

• a housing;
• a rotor mounted in the housing for rotation about an axis, having multiple vane slots adapted to receive a radially sliding vane therein;
• a cam surrounding said rotor, having multiple pairs of arcuate surfaces facing the vanes and adapted for contact thereby, each pair of surfaces having a rise zone in which vanes contacting the cam slide radially outward when the rotor turns and a fall zone in which vanes contacting the cam slide radially inward when the rotor turns, the rise zones being spaced mutually by a fall zone;
• a first pressure plate located at a first axial side of the rotor, having
• first and second inlet ports;
• first and second outlet ports, the first and second inlet ports being spaced mutually by the first outlet port in the direction of rotation;
• a first passage extending angularly from the first inlet port to the first outlet port;
• a second passage aligned with the radially inner end of the vane slots and extending angularly from the second inlet port to the second outlet port;
• and
• a second pressure plate located at a second axial side of the rotor, having
• first and second inlet ports;
• first and second outlet ports, the first and second inlet ports being spaced mutually by the first outlet port in the direction of rotation and aligned with corresponding inlet and outlet ports of the first pressure plate, the space between the cam, rotor, vanes and pressure plates defining pumping chambers whose size increases as distance of the arcuate surfaces from the rotor increases and decreases as distance of the arcuate surfaces from the rotor decreases;
• a first blind passage aligned with the radially inner end of the vane slots and extending angularly across the first outlet port;
• a second blind passage aligned with the radially inner end of the vane slots and extending angularly across the second outlet port;
• and
• a third passage aligned with the radially inner end of the vane slots and extending angularly across the first inlet port of the second pressure plate and communicating with an outlet port;
• and
• a fourth passage aligned with the radially inner end of the vane slots and extending angularly across the second inlet port of the second pressure plate and communicating with an outlet port.