4-wheel drive transmission control system

Patent · Tue Jun 16 00:00:00 EDT 1987

OSTI ID:6299277

Hosono, C; Hayakawa, Y; Kubo, S; Taga, Y; Nakamura, S

This patent describes a control system for a 4-wheel drive transmission including a transfer unit capable of establishing 2-wheel drive mode and 4-wheel drive mode by operation of first hydraulic means and capable of establishing low-speed and high-speed gear positions in the 4-wheel drive mode by operation of second and third hydraulic means, the control system comprising: a source of oil at line pressure; a manual valve having: an inlet port connected to the line pressure source, a first outlet port, a second outlet port for supplying the line pressure directly to the first hydraulic means, a first drain port, a second drain port, and a spool mechanically connected to a shift lever and shiftable between first, second and third positions; the inlet port being in fluid communication with the first outlet port and the second outlet port being in fluid communication with the second drain port when the spool is in the first position, the inlet port being in fluid communication with the first and second outlet ports when the spool is in the second position, the inlet port being in fluid communication with the second outlet port and the first outlet port being in fluid communication with the first drain port when the spool is in the third position; an automatic transfer control mechanism for supplying oil at a control pressure which varies according to vehicle speed; an inhibitor valve having: a first chamber; a second chamber; and a spool shiftable between a high-speed position and a low-speed position to selectively connect the oil pressure source and the second or third hydraulic means.

• Assignee: Aisin-Warner Limited and Toyota Motor Corp.
• Patent Number(s): US 4673072
• OSTI ID: 6299277
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330602* -- Vehicle Design Factors-- Engine-Transmission Matching
CONTROL
CONTROL EQUIPMENT
CONTROL SYSTEMS
DRAINAGE
EQUIPMENT
FLOW REGULATORS
HYDRAULIC CONTROL DEVICES
INTAKE STRUCTURES
LUBRICANTS
LUBRICATING OILS
MACHINE PARTS
MECHANICAL STRUCTURES
MECHANICAL TRANSMISSIONS
OILS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
PETROLEUM PRODUCTS
PRESSURE CONTROL
VALVES
VEHICLES
VELOCITY