| 摘要 |
PURPOSE:To prevent the connection of a clutch during the selection operation of an auxiliary transmission and eliminate the gear sqeak, etc., by installing an auxiliary transmission operation protecting circuit for prohibiting the stop of the selection control of the auxiliary transmission, when the selection operation of the auxiliary transmission is detected. CONSTITUTION:In a control circuit 26, a subselection control circuit 27 for connecting and disconnecting a clutch and selection-controlling an auxiliary transmission in the ordinary traveling is installed. Further, a selection prohibiting circuit 72 for suspending the selection control of the auxiliary transmission in the first speed shift of a main transmission, lowering of the lubricating oil temperature for the auxiliary transmission, and the reduction of the air pressure for operating an actuator is installed. Further, an auxiliary transmission protecting circuit 73 for prohibiting the compulsory stop of the selection control for the auxiliary transmission in the selection of the auxiliary transmission is installed. When the circuit 72 operates, the third transistor 76 operates as opening switch, and the supply of electricity into the first solenoid valve 25 is suspended, and a clutch is connected. In order to prevent this phenomenon, the operation of the circuit 72 is suspended by the circuit 73 during the selection of the auxiliary transmission. |
