SPEED CHANGE CONTROL METHOD FOR RUNNING TYPE SERVICE MACHINE

摘要

PURPOSE:To improve riding comfortableness at starting phase by making the duration time for forward first speed larger than that for forward second speed if high speed more than forward third speed is selected when a transmission is presently set in back gear or neutral. CONSTITUTION:In electrification control of the solenoid of a solenoid valve of the hydraulic unit in the transmission gear of a combine harvester, a formula 't(T7)-t(NDT7)>t(T3)' is satisfied provided that t(T7) is the width of pulse generated in ICT7 used for a timer, t(T3) is the width of pulse generated in ICT3 for similar use and t(NDT7) is a delay time of a on-delay circuit NDT7. Accordingly, the time under low speed run (forward first speed) until high speed run of forward third speed is obtained is made long, and the time under intermediate speed run (forward second speed) is made short. Then, uncomfortable feeling at quick start is well suppressed and comfortable feeling of ride can be obtained.