Patent GB-1166726-A (GB)
Title: Improvements in or relating to Power Transmission Mechanism Providing Changes of Gear Ratio
Inventor: POWER JOHN FORDHAM
IPC: F16H3/66
Filed: 1967-04-03
Abstract: 1,166,726. Variable speed epicyclic gear. AUTOMOTIVE PRODUCTS CO. Ltd. 12 March, 1968 [3 April, 1967], No. 15067/67. Heading F2D. A power transmission comprises clusters of two bevel pinions 14, 15 rotating together about axes which lie in planes radiating from an axis about which their carrier is rotatable, and meshing with other driving bevel gears 17, 19 and a driven bevel gear 22 rotating about the carrier axis. Clutches 27, 29 couple one or other of the driving bevel gears to an input shaft 10 and an additional clutch 28 couples the carrier 13 to the input shaft so that the carrier can be caused to rotate at the same speed as the input shaft. Function summary.-The transmission, which has fluid-operated clutches and brakes operated either manually or automatically in response to engine speed, provides three speed reduction ratios, a direct drive, two overdrive ratios and one reverse gear ratio. 1st Gear operation.-The clutch 27, which is engaged by a piston 54 acting on levers 56, couples a casing 26, driven by the input shaft 10 to a third shaft 12, so that the first input shaft bevel gear 17 rotates the output shaft 11 through the bevel gear clusters 14, 15 and the output bevel gear 22. This produces a reaction tending to rotate the carrier 13 backwardly which is absorbed by a one-way clutch 37. 2nd Gear operation.-Clutch 27 is engaged between casing 26 and third shaft 12 and a brake 34 is engaged on a drum 35 carrying a fourth bevel gear 23. The bevel pinion clusters 14, 15 are rotated by the first input bevel gear 17 causing the outer pinions 15 to roll around the fourth bevel gear 23 to rotate the output bevel gear 22 at a higher speed than if the carrier 13 was stationary. 3rd Gear operation.-Clutch 27 and a brake 32 are engaged. The latter acts on the driven member 31 of the clutch 29 which is connected to the second input bevel gear 19 so that the clusters 14, 15 are driven in the same manner as in 2nd Gear operation but roll around the second input bevel gear 19. Direct drive operation.-Clutches 27, 28 between the casing 26 and both the third shaft 12 and the sleeve 18 are engaged so that the whole train rotates bodily. Clutch 28 is engaged by a piston 55 acting on a lever 57. 1st Overdrive operation.-The clutch 28 between casing 26 and sleeve 18 is engaged and the brake 32 is applied to the driven member 31 of clutch 29 to stop the second driving bevel gear 19. Carrier 13 rotates with input shaft 10 causing inner bevel pinion 14 to roll around bevel gear 19 causing the outer bevel pinion 15 to drive the output bevel gear at a higher speed than the input shaft 10. 2nd Overdrive operation.-Clutch 28 between casing 26 and first sleeve 18 is engaged and the brake 34 is applied to drum 36 mounting the fourth bevel gear 23 providing the same effect as in 1st Overdrive operation except that clusters 14, 15 roll around the bevel gear 23 instead of bevel gear 19. Reverse drive operation.-Movement of a piston 64 engages the clutch 29 between casing 26 and a second sleeve 21 so that bevel gear 19 drives clusters 14, 15 and brake 33 is applied to stop carrier 13. Output bevel gear 22 and output shaft 11 are thus rotated in the opposite direction to the input shaft 10. The axes of the clusters 14, 15 may be displaced from the position normal to the axes of the carrier member to incline outwardly towards the input shaft end in order to lower the reverse gear ratio with respect to the 1st gear ratio and to change the relative values of all gear ratios.