| 摘要 |
PURPOSE:To improve escapability at a muddy place or the like by providing in an oil chamber at the back surface of the piston of a hydraulic clutch changing drive into a 2 wheel or 4 wheel drive, a spring consisting of a form memorizing alloy which elongates when the temperature of oil has reached above a fixed temperature. CONSTITUTION:A driving force transmission which is interveniently provided between a front wheel drive shaft 10 and a rear wheel drive shaft 11 has a hydraulic clutch 12 which is put into the state of contact by means of the discharged oil of a differential pump 16 discharging pressure oil according to the rotational speed difference between both shafts 10, 11. The hydraulic clutch 12 is made up of a number of clutch plates 13, a piston 14 which pushes these clutch plates 13 in the direction of contact and an oil chamber 15 supplied with pressure oil to push-move the piston 14. In this instance, a spring 21 consisting of a form memorizing alloy is provided at the back surface of the piston 14 of the oil chamber 15 of the hydraulic clutch 12. This spring is made to be form-memorized so as to elongate at above a fixed temperature, and enables the hydraulic clutch 12 to be locked in the state of contact at its elongation time.
|
