Line pressure control device for hydraulic control system of automatic transmission

Patent · Tue Jul 14 04:00:00 EDT 1987

OSTI ID:6340946

Kumura, H; Abo, K; Hirano, H; Yamamuro, S; Nakano, M

This patent describes a line pressure control device for a hydraulic control system of an automatic transmission, comprising: a fluid pump for producing a line pressure; line pressure passage means connected to the fluid pump for distributing the line pressure; a source of intake manifold vacuum; a vacuum diaphragm unit connected to the source of intake manifold vacuum for producing a variable force depending upon variations of the intake manifold vacuum; and a control valve connected to the line pressure passage means and having a valve spool movable to regulate the line pressure based upon the force applied from the vacuum diaphragm unit; the vacuum diaphragm unit including a casing having an inner wall, parallel first and second diaphragms disposed within the casing, vacuum chamber means defined within the casing by one side of the first diaphragm and by one side of the second diaphragm, atmospheric pressure chamber means defined within the casing by other sides of both the first and the second diaphragms in such a manner that the first diaphragm is subject to a differential pressure. It is urged away from the valve spool while the second diaphragm is subject to a differential pressure by which it is urged toward the valve spool. Spring means urges the first diaphragm toward the valve spool while the second diaphragm moves away from the valve spool, and rod means for connecting the first and second diaphragms to the valve spool. The first and second diaphragms, the spring means and the rod means are constructed and arranged so that the force reduces as the intake manifold vacuum increases and is supplied from the first diaphragm to the valve spool through the rod means when the intake manifold vacuum is lower than a first predetermined value.

• Assignee: Nissan Motor Co., Ltd., Yokohama
• Patent Number(s): US 4679466
• OSTI ID: 6340946
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330602* -- Vehicle Design Factors-- Engine-Transmission Matching
CONTROL
CONTROL EQUIPMENT
EQUIPMENT
FLOW REGULATORS
FLUIDS
HYDRAULIC CONTROL DEVICES
HYDRAULIC FLUIDS
MACHINE PARTS
MECHANICAL TRANSMISSIONS
PRESSURE CONTROL
PRESSURE REGULATORS
PUMPS
VACUUM SYSTEMS
VALVES
VEHICLES
WORKING FLUIDS