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US 5,113,720 AGranted
Apparatus for controlling gear box
AssigneeKabushiki Kaisha Komatsu Seisakusho
InventorsYoshio Asayama, Makio Tsubota, Yasunori Okura, Takayuki Sato
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AssigneeKabushiki Kaisha Komatsu Seisakusho
InventorsYoshio Asayama, Makio Tsubota, Yasunori Okura, Takayuki Sato
Estimating the term…
During shift change, a discrimination is made as to a load, a quantity of residual hydraulic oil in respective shift change clutches (F, R, 1 to 4) and a state of shift change which has been effected from what speed stage to what speed stage so that a pattern of electrical commands to be issued to pressure control valves for required shift change clutches is variably controlled depending on results derived from the above discrimination. Thus, smooth shift change can always be achieved regardless of running conditions. Electrical commands to be fed to the respective pressure control valves are compared with electrical currents outputted from drive circuits and outputs from clutch pressure detecting means for each clutch, whereby an abnormality is detected with the relevant clutch based on results derived from the comparison. Once an abnormality is detected, an adequate disposal for processing the abnormality is executed so as to reliably prevent double engagement from taking place with clutches.
An apparatus for controlling a gear box including a plurality of shift change clutches, a plurality of pressure control valves separately connected to said shift change clutches to individually control hydraulic pressure in each of said shift change clutches, each of said pressure control valves comprising a first valve including a spool having an orifice formed at an output port thereof which leads to a clutch, said first valve being opened and closed by a differential pressure across said orifice, and a spring, and a second valve in the form of a pressure control valve adapted to be actuated in response to an electric signal, said second valve operating to open said first valve by feeding to the first valve hydraulic oil delivered from a hydraulic pump during the shift change and gradually increasing clutch hydraulic pressure after filling said clutch with oil and a plurality of drive circuits for feeding an electric current to said pressure control valves in response to an input clutch hydraulic pressure command;
An apparatus for controlling a gear box including a plurality of pressure control valves separately connected to a plurality of shift change clutches to individually control hydraulic pressure in said shift change clutches and a plurality of drive circuits for feeding to said pressure control valves an electric current corresponding to an inputted clutch hydraulic pressure command, said apparatus comprising;
Dependencies are inferred from the claim text.