Regulator valve for hydraulic control system including variable displacement pump
A hydraulic control system is described for an automotive automatic transmission comprising: an automatic transmission actuated by hydraulic fluid; a variable capacity pump for supplying hydraulic fluid under pressure for actuating the automatic transmission. The pump has a control arrangement including a control chamber which varies the capacity of the pump in response to the pressure prevailing therein. A pressure regulator valve is described for regulating the output of the pump by draining off some of the fluid discharged by the pump and developing a control pressure, the regulator valve including a bore formed with: a first port which receives the output of the pump, a second port which fluidly communicates with the control chamber, and a drain port, the regulator valve further including a spool which is reciprocatively disposed in the bore and which is formed with first and second lands. The first land defines a first variable orifice between the first and second ports and the second land defining a second variable orifice between the second and drain ports; and a fixed flow restriction within the bore, for restricting fluid communication between the first and second ports and the second and drain ports. The fixed flow restriction is defined between the wall of the bore and a first portion of the spool which extends between the first and second lands. The portion has a diameter which is selected with respect to the diameter of that portion of the bore in which it is disposed so as to define a gap having a maximum width of 1.5 mm.
- Assignee:
- Nissan Motor Co., Ltd., Yokohama
- Patent Number(s):
- US 4632638
- OSTI ID:
- 6777372
- Country of Publication:
- United States
- Language:
- English
Similar Records
Automatic transmission for automotive vehicles
4-wheel drive transmission control system
Related Subjects
330602* -- Vehicle Design Factors-- Engine-Transmission Matching
CONTROL EQUIPMENT
DIMENSIONS
DRAINAGE
EQUIPMENT
FLOW REGULATORS
FLUIDS
HYDRAULIC CONTROL DEVICES
HYDRAULIC FLUIDS
MACHINE PARTS
MECHANICAL TRANSMISSIONS
OPENINGS
ORIFICES
PRESSURE REGULATORS
PUMPS
VALVES
VEHICLES
WIDTH
WORKING FLUIDS