STRUCTURE OF AUTOMATIC TRANSMISSION OF WORKING CAR

摘要

PROBLEM TO BE SOLVED: To carry out an appropriate automatic speed changing operation without causing such strange feeling that the swash plate of a variable displacement motor is switched over from a low speed position to a high speed position irrespective of an operator's intention. SOLUTION: An automatic transmission comprises: an operating position detecting means 29 for detecting the operating position of a speed change operating member 24 to be manually operated; a load detecting means 47 for detecting an engine load; a motor operating means 55 for switching over the swash plate of the variable displacement motor 17 provided in a hydrostatic non-stage transmission device 10 to any of two stages high and low; and a control means 31 for controlling the operation of the motor operating means 55. The control means 31 controls the operation of the motor operating means 55 such that the swash plate 17A of the variable displacement motor 17 is changed from the low speed position to the high speed position when the speed lowering operation of the speed change operating member 24 has not been detected from the detection by the operating position detecting means 29, in the state where it is detected from the detection of the load detecting means 47 that the engine load has been lowered to be lower than a preset value for changing the low and high speeds. COPYRIGHT: (C)2008,JPO&INPIT