US 12,173,788 B2
Control system and method thereof for multispeed transmission
Eric Tryon, Fishers, IN (US); Charles F. Long, Zionsville, IN (US); and Bryan Hagelskamp, Carmel, IN (US)
Assigned to ALLISON TRANSMISSION, INC., Indianapolis, IN (US)
Filed by ALLISON TRANSMISSION, INC., Indianapolis, IN (US)
Filed on Jun. 26, 2023, as Appl. No. 18/214,043.
Application 18/214,043 is a continuation of application No. 17/343,933, filed on Jun. 10, 2021, granted, now 11,725,724.
Application 17/343,933 is a continuation of application No. 16/013,032, filed on Jun. 20, 2018, granted, now 11,047,474.
Claims priority of provisional application 62/527,202, filed on Jun. 30, 2017.
Prior Publication US 2023/0332682 A1, Oct. 19, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. F16H 61/02 (2006.01); F15B 11/20 (2006.01); F15B 13/06 (2006.01); F16H 61/00 (2006.01); F16H 61/12 (2010.01); F16H 59/68 (2006.01)
CPC F16H 61/0021 (2013.01) [F15B 11/20 (2013.01); F15B 13/06 (2013.01); F16H 61/0206 (2013.01); F16H 61/12 (2013.01); F15B 2211/71 (2013.01); F16H 2059/683 (2013.01); F16H 2061/026 (2013.01); F16H 2061/1204 (2013.01); F16H 2061/1292 (2013.01); F16H 2200/0065 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An electro-hydraulic control system for a multispeed transmission, comprising:
a controller for operably controlling the transmission;
a fluid source for supplying hydraulic fluid;
a plurality of torque-transmitting mechanisms being operably selected between an applied and an unapplied state to achieve a plurality of ranges including at least one reverse, a neutral, and a plurality of forward ranges, wherein in any one of the plurality of forward ranges only two of the plurality of torque-transmitting mechanisms are in the applied state;
a plurality of shift valves each of which is disposed in fluid communication with the fluid source and configured to move between a stroked position and a de-stroked position, the plurality of shift valves including at least a first shift valve, a second shift valve and a third shift valve;
wherein, when operating in a first forward range at a high transmission output speed, a first torque-transmitting mechanism and a second torque-transmitting mechanism are in their applied states and the other of the plurality of torque-transmitting mechanisms are in their unapplied states;
wherein, when a shift from the first forward range to neutral is made immediately followed by a loss of electrical power in the system, a hydraulic latch is formed by hydraulic fluid against at least one of the first, second and third shift valves such that the at least one of the first, second and third shift valves is maintained in its stroked position due to the latch.