Fast valve actuation system for an automatic transmission
AssigneeAllison Transmission, Inc.
InventorsCharles F. Long, Darren J. Weber
Life of this patent
Estimating the term…
Abstract
A fast valve actuation system for an automatic vehicle transmission includes a pair of spring-biased shift valves. Solenoids control the application of pressurized hydraulic fluid to the head of each of the shift valves. Each shift valve has at least one port that is coupled to a fluid chamber of a torque transferring mechanism of an automatic transmission. The position of each of the shift valves determines whether its ports are connected with fluid pressure. Fluid passages connect the head of each shift valve to the spring pocket of the other shift valve.
Claims20
An electro-hydraulic control for an automatic transmission, comprising
- a first shift valve axially translatable in a first valve chamber of a hydraulic control circuit for an automatic transmission, the first shift valve comprising a first valve head, a first spool, a first plurality of axially-spaced lands defining a plurality of ports on the first shift valve, at least one of the ports being in fluid communication with a first torque transferring mechanism of the automatic transmission, and a first spring chamber axially spaced from the first valve head,
- a first electro-hydraulic actuator having a first output in fluid communication with the first shift valve,
- a second shift valve axially translatable in a second valve chamber of the hydraulic control circuit, the second shift valve comprising a second valve head, a second spool, a second plurality of axially-spaced lands defining a plurality of ports on the second shift valve, at least one of the ports being in fluid communication with a second torque transferring mechanism of the automatic transmission, and a second spring chamber axially spaced from the second valve head,
- a second electro-hydraulic actuator having a second output in fluid communication with the second shift valve,
- a first passage fluidly coupling the first valve head and the second spring chamber to the first output, and
- a second passage fluidly coupling the second valve head and the first spring chamber to the second output.
An automatic transmission, comprising:
- a variable ratio unit to transfer torque from a vehicle drive unit to a transmission output shaft, and
- a hydraulic circuit fluidly coupled to the variable ratio unit, the hydraulic circuit comprising
- a first fluid chamber pressurizable to apply a first torque transferring mechanism of the variable ratio unit,
- a second fluid chamber pressurizable to apply a second torque transferring mechanism of the variable ratio unit,
- a first shift valve fluidly coupled to the first fluid chamber to selectively direct fluid pressure to the first fluid chamber, and
- a second shift valve fluidly coupled to the second fluid chamber to selectively direct fluid pressure to the second fluid chamber, the first and second shift valves being in fluid communication with each other to connect one of the first and second fluid chambers to fluid pressure and disconnect the other of the first and second fluid chambers from fluid pressure in rapid succession.
Dependencies are inferred from the claim text.