| 摘要 |
1,247,275. Reversing gear; friction clutches. CATERPILLAR TRACTOR CO. 25 Nov., 1969 [12 Dec., 1968], No. 57531/69. Headings F2C and F2D. A marine reversing gear comprises nested multi-disc friction clutches 27, 25 housed in a casing 15, fast with an engine-driven flywheel 17, and selectively hydraulically operated by a freely floating common piston 37 for ahead or astern drive to an output shaft 23 via a quill shaft 31 and gears 19, 51 or an inner shaft 29 and gears 21, 69, 71 respectively to a hollow shaft 53 which drives a planetary final drive reduction gear 59, the planet carrier 61 of which is integrally formed with the output shaft 23. The hydraulic pressure is supplied via a control valve 75 and ducts 79 or 87 to one or other side (45 or 47) of the common piston 37 for ahead or astern drive via centrifugally responsive dump valves 83 or 89, the appropriate valve piston 91 being inwardly moved by the hydraulic pressure to close an exhaust port 95 and connect the clutch piston chambers 45 or 47 to the pressure supply via ducts 93, the valve pistons 91 being outwardly moved centrifugally, on cut off of hydraulic pressure via the control valve 75, to evacuate the clutch piston chambers via the exhaust ports 95 and 97 for clutch disengagement, the outer clutch discs 35 being shaped in a Belleville spring form to ensure complete clutch disc separation. The freely floating common piston 37 rotatably slips during initial clutch engagement to avoid shock loading and effect a smooth clutch take-up. |
