SPEED CHANGE CONTROL METHOD FOR HYDRAULIC SPEED CHANGE/STEERING MACHINE

摘要

PURPOSE:To keep a clutch from a shock and abrasion at the time of changing a speed by multiplying and reducing the speed change step when a velocity difference is caused short of a shock and abrasion at a clutch at the time of changing over the clutch. CONSTITUTION:During a certain speed step, a speed change gear is adapted to conduct multiplying operation when the relative rotational frequency Nup of a clutch at the upper speed step is smaller than a certain value Nc for velocity difference short of shock or abrasion generated at the clutch at the time of changing over the clutch and the target engine rev count NE is smaller than the actual engine rev count nE. When the relative rotational frequency Ndown of the clutch at the lower speed step is smaller than the above value Nc and a value obtained by subtracting a fixed certain rotational frequency Nconst from the target engine rev count NE is larger than the actual engine rev count nE, speed reduction operation is conducted.