| 摘要 |
1,200,261. Change-speed control. SCANIAVABIS A.B. 13 March, 1968 [17 March, 1967], No. 12178/68. Heading F2D. A two-speed epicyclic gear unit 4 between input and output shafts 3, 12 is actuated by an axially movable shift collar 41 engageable with the planet carrier 20 or sun pinion 35 and rotated into synchronism prior to engagement by one of a pair of friction clutches 10, 11, the shift rod 56 carrying pistons 60 and 61, 62 of conjointly operable pneumatic servo actuators 54, 55 for a clutch-operating yoke 50 and a collar shift fork 44. The pistons 61, 62 are permitted limited axial movement on rod 56 by stop rings 63, 64, 65. The shift cylinder 55 is provided with air supply lines 84, 86 and an exhaust line 85, the synchronizer cylinder 54 being provided with supply lines 71, 72 connected to lines 84, 86 through valves 73, 74. The air inlet ports in shift cylinder 55 are smaller than those in synchronizer cylinder 54 to ensure rapid operation of synchronizer piston 60. To effect a gear change air is supplied simultaneously to the appropriate ends of cylinders 54, 55, piston 60 operating immediately through yoke 50 to engage clutch 10 or 11, so that collar 41 is rotating at appropriate speed when moved to the engaging position by rod 56 and fork 44. Upon completion of gear change the appropriate valve 73, 74, by engagement of its lower end in a recess in shift rod 56, is opened to exhaust synchronizer cylinder 54 and thus release the engaged clutch. |
