Lubrication of a manual transmission involves feeding lubricating oil to, for example, bearings for an input shaft and an output shaft, meshing engagements of speed change gears, and loosely-fitting engagements for gears provided for the input and output shafts and a synchronizer. Such oil is typically fed by oil pick-up feeding. Specifically, the oil stored on the bottom of a transmission case is picked up by rotating gears, received by a gutter-shaped oil-feeding member, and then fed to each of those parts to be lubricated.
For example, Patent Document 1 discloses an oil feeding apparatus that is included in a transmission case combined with a case for a differential gear system, and used for a vehicle having a front-engine, front-wheel-drive (FF) layout. The oil feeding apparatus picks up oil with a large-diameter differential ring gear which is arranged at the lowest internal portion of the transmission case and which provides power from the transmission to the differential gear system. Then, the oil feeding apparatus introduces this oil from the front (near the engine) of the transmission to a storage member (oil-feeding member) arranged above input and output shafts such that the oil is poured into a storage part of the storage member. After that, the oil feeding apparatus guides the oil to the rear (across from the engine) of the transmission to allow the oil to drip from an oil-dripping hole which is cut through the bottom of the storage part, to the input shaft, the output shaft, the meshing engagements of the speed change gears, and the synchronizer, as well as to feed the oil from a rear end of the input shaft to an intra-shaft oil passage inside the input shaft.
The oil feeding apparatus disclosed in Patent Document 1, however, primarily uses the differential ring gear to feed the picked up oil to each of the parts to be lubricated. Thus, the oil feeding apparatus cannot sufficiently catch the picked up oil in the storage member when the vehicle is moving backward; that is, when the differential ring gear is rotating in the reverse direction. Hence, when the vehicle is reversed, each of the parts to be lubricated could be fed with the oil in an insufficient amount.
In contrast, Patent Document 2 discloses the use of driven gears that are loosely fitted to an output shaft, which is positioned lower than an input shaft, and in particular, the use of a driven gear having a relatively large diameter and included in a gear train for a transmission gear range of forward and low speed. The rotation of this driven gear allows the oil stored on the bottom of a transmission case to be picked up, and then caught in an oil gutter (i.e., oil-feeding member).
This allows the driven gear (which is loosely fitted to the output shaft and included in the gear train for the transmission gear range of forward and low speed) to rotate in the same direction when the vehicle moves backward as well as forward. As a result, even when the vehicle moves backward, the oil can also be picked up, caught by the oil-feeding member, and then fed to each of those parts to be lubricated.
USPTO Backgrounds
USPTO Backgrounds