Patent attributes
In a traveling transmission in which an auxiliary transmission is interposed between a main clutch and a mechanical transmission, the auxiliary transmission is configured such that power transmission is cut out interlockingly with the disengagement operation of the main clutch. For example, the auxiliary transmission is configured as a high-low speed selector device including a hydraulic-operated first hydraulic clutch and a spring-operated second hydraulic clutch. Preferably, there should be provided a controller for changing the position of a direction switching valve for the first and second hydraulic clutches based on the operation of an operating member such as a pedal for disengaging the main clutch. According to the present invention, it is possible to shorten a time required for a speed change operation by the mechanical transmission and, also, to achieve a smooth operation by the mechanical transmission.