GB1003911A - Improvements in relating to variable speed gears - Google Patents

Abstract

1,003,911. Change-speed epicyclic and reverse gear; ratchet clutches. MASSEY-FERGUSON (UNITED KINGDOM) Ltd. Oct. 5, 1961 [Oct. 11, 1960], No. 34730/60. Headings F2C, and F2D. [Also in Division B7] In a three-speed sun-ring epicyclic gear 25 for tractors, which gear is capable of gear-shift under load, a sun 29 (or annulus, Fig. 3, not shown) is fixed, an input shaft 23 selectively drives a rotatable annulus 65 (or sun, Fig. 3, not shown) through a one-way clutch 62, or a planet carrier 73 through a manually-controlled, hydraulically actuated, multiplate friction clutch 69, and an output shaft 31 is selectively driven by the planet carrier through a further one-way clutch 93, or by the rotatable annulus (or sun) through a further manually-controlled, hydraulically actuated, multiplate friction clutch 81. The one-way clutches 62, 81 comprise spring-engaged, facially toothed clutch members mounted on helical splines to disengage on overrun. Reduced drive is by disengagement of both friction clutches 69, 81 for drive through the one-way clutch 62, the annulus 65, the carrier 73 and the one-way clutch 93. Direct drive is by engagement of the friction clutch 69 only for drive through the latter, the carrier and the one-way clutch 93, the clutch 62 overrunning; alternatively by engagement of the friction clutch 81 only for drive through the one-way clutch 62, the annulus and the friction clutch 81, the clutch 93 overrunning. Overdrive is by engagement of both friction clutches 69, 81 for drive through the friction clutch 69, the carrier, the annulus and the friction clutch 81, both clutches 62, 93 overrunning. Control is by a manuallyshiftable valve. In the arrangement shown, which provides nine speeds both forward and reverse, a bevel reversing gear 34 and a further three-speed sun-ring epicyclic gear 58 are arranged in series following the epicyclic gear 25. The reversing gear 34 comprises bevel pinions 38 mounted on a carrier 46 and meshing side wheels 39, 40 respectively splined to a gear 33 driven by a gear 32 on the output shaft 31 of the gear 25 and to a hollow layshaft 37 which drives a hollow input shaft 136 of the further epicyclic gear 58 through gears 57, 56. Leftward and rightward movement of a clutch/brake ring 45 splined on the carrier 46 respectively clutches the carrier to the gear 33 to lock-up the reversing gear for forward drive, and brakes the carrier by engagement with a fixed ring 52 for reverse drive. The further epicyclic gear may be similar to that, 25, or, as shown, may comprise a fixed annulus 130, a dog clutch sleeve 137 splined on the hollow input shaft 136 and leftwardly and rightwardly slidable respectively to engage a sun 134 or a planet carrier 132 and a dog clutch sleeve 144 splined on an output shaft 59 driving the tractor rear-axle gearing and rightwardly and leftwardly slidable respectively to engage the sun 134 or the carrier 132. The further epicyclic gear provides reduced drive when both sleeves 137, 144 are shifted to the left for drive through the sun 134 and carrier 132, direct drive when the sleeves 137, 144 are shifted to the left and right respectively for drive through the sun, and overdrive when both sleeves 137, 144 are shifted to the right for drive through the carrier and the sun. In an arrangement in which the further epicyclic gear is similar to that, 25, to enable gear-shift under load for all speeds, it is essential, due to the oneway clutches, to position the reversing gear following the further epicyclic gear, unless a limited range of reverse speeds is acceptable or means are provided for locking in and out the one-way clutches. A hollow shaft 14 surrounding the input shaft 23 drives, through gears 15, 16, a shaft 17 having splined thereto a collar 20 which couples the shaft 17 to a powertake-off and comprises a gear 21 driving an oil pump for the gear control system. The shafts 23 and 14 are engine driven through a dual plate clutch (not shown), whereby the power take-off and the tractor land-wheel drive are successively disconnected by clutch pedal depression. In Fig. 2 (not shown), the first epicyclic gear is layshaft mounted and drives the further epicyclic gear, mounted coaxially with the engine-driven input shaft, through a forward and reverse spur gearing controlled by a sliding dog clutch.