To provide a hydrostatic continuously-variable-transmission (CVT) which can suppress the temperature rise of working fluid in a closed hydraulic circuit.
The hydrostatic continuously-variable-transmission (CVT) is configured so as to carry out the continuously variable speed changing by connecting a hydraulic pump P and a hydraulic motor M via a closed hydraulic circuit, and by variably controlling the displacement of the hydraulic motor. A valve spool 70 is arranged in a spool bore 6d formed in an output shaft 6 of the transmission, which output shaft rotatably supports the hydraulic pump and the hydraulic motor. The output shaft 6 of the transmission is provided with outside branched oil passages 6b, 6c which communicate with an outside passage 57 and are opened to the spool bore, and an inside branched oil passage 6a which communicates with an inside passage 56, and is opened to the spool bore. The valve spool can move between the clutch disengaging position for allowing the outside branched oil passages 6b, 6c to communicate with the inside branched oil passage 6a by a right groove portion 72 provided on the outer periphery of the valve spool 70 and the clutch engaging position for closing at least a high pressure clutch port by the central land portion 73 of the valve spool. The right groove portion 72 communicates with the outside via a discharging oil passage having an orifice hole 70d.
| JP4451171 | Hydrostatic continuously variable transmission |
| WO/1984/001804 | INFINITELY VARIABLE HYDRAULIC TRANSMISSION |
| JP3079230 | SWASH PLATE TYPE HYDRAULIC GEAR |
NAKAMURA KAZUHIKO
SAKAKIBARA KENJI
SUGANO YOSHIHISA
MITSUBORI TOSHIMASA
