Compound transmission

A compound transmission (110) comprising a multiple speed first section (112) connected in series with a multiple speed second section (114), said first and second sections contained within a common housing defining a forward end wall (116A) and a rearward end wall (116B);

• said first section comprising an input shaft for connection to a prime mover, at least one input gear fixable to said input shaft, a mainshaft generally coaxial with said input shaft and extending into said second section, at least one first section countershaft rotatably supported in said housing and having a first first section countershaft gear (130) and a second first section countershaft gear (134, 136) fixed thereto, said first first section countershaft gear constantly meshed with said input gear, at least one mainshaft gear surrounding said mainshaft and constantly meshed with said second first section countershaft gear and first section clutch means carried by said mainshaft for selectively fixing said mainshaft gear to said mainshaft for rotation therewith;
• said second section comprising at least one second section countershaft coaxial with said first section countershaft and rotatably supported in said housing, an output shaft generally coaxial with said mainshaft rotatably supported in said housing, a first second section countershaft gear (168, 170) and a second second section countershaft gear (170, 172) fixed to said second section countershaft, said first second section countershaft gear constantly meshed with a first central gear (174, 176) fixable to said mainshaft, at least one second central gear (176, 178) constantly meshed with said second second section countershaft gear and second section clutch means (180, 182) for selectively clutching at least one of (i) said first central gear to said mainshaft, (ii) said second central gear to said output shaft, and (iii) said mainshaft to said output shaft;
• said transmission characterized by:
• said first and second section countershafts being independently rotatable in said housing and together defining an assembly of countershafts rotatably supported in said housing solely by bearing means (126, 162D) mounted in said forward end wall and in said rearward end wall.

A vehicular compound change gear transmission (110/310) comprising a multiple speed main transmission section (112/312) connected in series with a multiple speed auxiliary transmission section (114/314) of one of the range, splitter or combined range/splitter type, said main transmission section and auxiliary transmission section contained within the common transmission housing (116/316) defining a forward end wall (116A/316A) and a rearward end wall (116B/316B);

• said main transmission section comprising an input shaft (118/318) for connection to a prime mover and rotatably supported in said housing by input shaft bearings (118C/318C) carried by said forward end wall, at least one input gear (120/320) rotatably fixable to said input shaft for rotation therewith, a mainshaft (146) generally coaxial with said input shaft and extending into said auxiliary transmission section, a plurality of main section countershafts (124) equally circumferentially spaced about said mainshaft, rotatably supported in said housing and driven by said input shaft, a plurality of main section countershaft gears (134, 136, 138) fixed to each of said main section countershafts, one of said main section countershaft gears fixed to each of said main section countershafts constantly meshed with said input gear, a plurality of mainshaft gears (140, 142, 144) surrounding said mainshaft and each constantly meshed with one of said main section countershaft gears fixed to each of said main section countershafts and main section clutch means (148, 150) carried by said mainshaft for selectively fixing selected ones of said mainshaft gears to said mainshaft for rotation therewith;
• said auxiliary transmission section (114) comprising a plurality of substantially identical auxiliary section countershafts (162) coaxial with said main section countershafts and rotatably supported in said housing, an output shaft (158) generally coaxial with said input shaft and said mainshaft and rotatably supported in said housing by output shaft bearing mean (158D) carried by said rearward end wall (116B), a first auxiliary section countershaft gear (168, 170) and a second auxiliary section countershaft gear (170, 172) fixed to each of said auxiliary section countershafts, said first auxiliary section countershaft gear constantly meshed with a first central gear (174, 176) fixable to said mainshaft, a second central gear (176, 178) constantly meshed with a second auxiliary section countershaft gear fixed to each of said auxiliary section countershafts and auxiliary section clutch means (182) for selectively clutching at least one of (i) said first central gear to said mainshaft, (ii) said second central gear to said output shaft or (iii) said mainshaft to said output shaft;
• said transmission characterized by:
• said main transmission section countershafts and said auxiliary section countershafts being independently rotatable in said housing and coaxial ones of said main transmission section countershafts and said auxiliary transmission countershafts together defining an assembly of countershafts rotatably supported in said housing solely by bearing means (124A, 162D) mounted in said forward end wall and in said rearward end wall.