Patent ID: 7017343

Claim:
A hydraulic pump for supplying fluid to a hydraulic motor for driving an axle, comprising: a movable swash plate for adjusting the amount of fluid supplied to said hydraulic motor, wherein said movable swash plate is shiftable between a neutral position for substantially zeroing the amount of fluid supplied to said hydraulic motor and a maximum position for maximizing the amount of fluid supplied to said hydraulic motor through a fixed intermediate position for supplying a certain amount of fluid to said hydraulic motor; a housing formed with a fluid sump therein, said housing having a pump support portion, wherein said hydraulic pump is disposed in said fluid sump and rotatably supported by said pump support portion of said housing; a hydraulic circuit formed in said pump support portion of said housing so as to fluidly connect said hydraulic pump to said hydraulic motor; and means for controlling hydraulic pressure in said hydraulic circuit, said means mechanically interlocking with said movable swash plate of said hydraulic pump, wherein said means keeps a certain low hydraulic pressure in said hydraulic circuit lower than a value for ensuring substantial traveling drive of said axle before said movable swash plate shifted from said neutral position reaches said fixed intermediate position.