CONTROL STRUCTURE FOR CONTINUOUSLY VARIABLE TRANSMISSION TYPE WORKING VEHICLE

摘要

PROBLEM TO BE SOLVED: To prevent a practical vehicle speed from getting different from a supposed speed by controlling an output shaft by a shift position correcting means, when an error is generated between a set shift output rotation speed and a detecting shift output rotation speed in setting the advancement. SOLUTION: A movable swash plate of a hydraulic pump moves to a set position by a lever operation of a continuously variable transmission 3 and the lever set position is detected by a lever angle sensor S3. When a set value is set in a rotation speed setting device 23 in response to the detected value and the setting of the advancing area of the movable swash plate position is confirmed, a controller C reads the set value by the set device 23 based on the detected value. It confirms that it is within a work rating rotation speed or less and reads the value detected by a rotation speed sensor S2. An error allowable quantity is calculated based on the rotation speed set value, and when the rotation speed detection value is higher than the upper limit value of the error allowable range of the rotation speed set value, the movable swash plate is moved to the low speed side by a swash plate control motor 8 so as to reduce the vehicle speed. The vehicle speed is increased in the reversed case. The practical vehicle speed is thus matched to the supposed shift position rightly.