Patent GB-1190972-A (GB)
Title: Improvements in or relating to Gearboxes
IPC: F16H3/44
Filed: 1967-05-18
Abstract: 1,190,972. Change-speed gear. SOC. ANON. DE VEHICULES INDUSTRIELS ET D'EQUIPEMENTS MECANIQUES SAVIEM. 18 May, 1967 [18 May, 1966], No. 23250/67. Heading F2D. A change-speed gear comprises a countershaft gear C having two input pinions 10, 11 which are selectively driven either separately through input clutches 3, 1 or differentially together through a bevel differential gear 5, 7, 8 and a third input clutch 2. As shown the countershaft gear has pinions 17, 18, 19, 30 freely rotatable on a countershaft C and respectively in permanent mesh with the input pinions 11, 10 and pinion 12, 29 freely rotatable on an output shaft B. The pinions 17, 19, 30, 12, 29 are selectively connected to the counter and output shafts C, B by dog clutches 21, 23, 14 and dog clutches 16, 22 respectively connect the input pinion 10 to the output shaft B and interconnect the pinions 18, 19. A pinion 20 fast with the countershaft C meshes a pinion 13 freely rotatable on the output shaft B and connectible thereto by a dog clutch 15. The odd ratios are in geometric progression and a synchronizing train comprises an additional countershaft D carrying a fixed pinion 34 in mesh with the input pinion 11 and freely rotatable pinions 33, 31 in mesh with the input pinion 10 and a pinion 32 fast with the pinion 10. The pinions 33, 31 are selectively connected to the countershaft D by friction clutches 37, 38. The lowest three ratios are provided by engaging the dog clutches 15, 21, 22, 23 with pinions 13, 17, 18, 19, first speed being through the clutch 3 and gear pairs 10, 18; 20, 13. In second speed the clutch 2 drives differentially through gear pairs 10, 18; 11, 17 to the final gear pair 20, 13 and third speed is through the clutch 1 and gear pairs 11, 17; 20, 13. During shift to fourth ratio the dog clutch 23 is initially disengaged whereafter the clutch 38 is engaged to synchronize the elements of the dog clutch 14 prior to its engagement. When the dog clutch 14 is engaged the clutches 1, 38 are disengaged and the clutch 2 engaged to drive differentially through gear pairs 10, 18; 11, 17 and 19, 12; 20, 13. Fifth speed is through the clutch 3 and gear pairs 10, 18; 19, 12. For sixth speed the dog clutch 15 is disengaged and the dog clutch 23 engaged with the pinion 19 after synchronism produced by engaging the clutch 37. The clutch 2 then drives differentially through the gear pairs 10, 18 ; 11, 17 to the gear pair 19, 12. Seventh speed is through the clutch 1 and gear pairs 11, 17 ; 19, 12. Eighth speed is produced by disengaging the dog clutch 22 and engaging the dog clutch 16 whereupon the clutch 2 drives differentially directly through the dog clutch 16 and through the gear pairs 11, 17; 19, 12. Ninth speed, direct drive, is through the clutch 3 and dog clutch 16. For tenth speed the dog clutch 14 is disengaged and the dog clutch 22 engaged, the clutch 2 driving differentially directly through the dog clutch 16 and through the gear pairs 11, 17; 18, 10 whilst eleventh speed is through the clutch 1 and gear pairs 11, 17 ; 18, 10. A creeper speed is provided by engaging the dog clutches 15, 22, 23 with the pinions 13, 18, 30, the clutch 1 driving through gear pairs 10, 18; 19, 12; 29, 30; 20, 13. For reverse the carrier 7 of the bevel differential is held by a brake 28 and the-clutch 1 drives the input pinion 10 of the creeper power path in reverse. In Figs. 1 and 14 (not shown) the additional synchronizing train D is omitted and the individual dog clutches may have synchronizing means therein. In Fig. 1 the creeper gear pair 29, 30 is omitted.