A transmission includes a transmission main housing, an intermediate plate secured to the transmission main housing; and a rear housing attached to the intermediate plate. An input shaft is connected to an extension shaft including a plurality of splitter gears selectively couple-able to the extension shaft. A main shaft is rotatably supported on the extension shaft and includes a plurality of main box gears selectively couple-able to the main shaft. A range shaft is drivingly connected to the main shaft and provides input to a planetary gear assembly, the range shaft being supported by a first bearing disposed within the intermediate plate and further including a bore disposed within a forward end. The extension shaft is supported at a first end by a bearing assembly within a partition wall and a second end is supported by a bearing assembly disposed within the bore in the range shaft.

Disclosed is a driving system having an oil circulation structure in which churned oil is collected in a housing and in which the collected oil is efficiently distributed to driving structures, which include a motor and a speed reducer, thereby smoothly cooling and lubricating the respective driving structures. In addition, it is possible to adjust the level of the oil depending on whether the driving structures are in a low-load state or a high-load state, thereby improving lubrication and cooling performance.

A transmission device includes a power-transmission case having a carrier of a reduction gear and a differential case joined to the carrier is supported in a transmission case via case support bearings, a specific planetary gear portion of a planetary gear is disposed on one side of a differential mechanism in an axial direction, and the specific case support bearing is disposed on the other side thereof An oil passage-forming body is provided on an inner wall of the transmission case, the oil passage-forming body comprising an oil collection part that opens upward and can collect lubricating oil splashed up in an area around the specific planetary gear portion within the transmission case accompanying rotation of the power-transmission case, and an oil reservoir part that is continuous from the oil collection part, stores lubricating oil collected by the oil collection part, and supplies the lubricating oil to the specific case support bearing.

A powertrain assembly includes one or several electric motors, a gearbox comprising a gearbox housing, an axle comprising: an axle housing, movable parts inside axle housing, comprising a shaft for a wheel, a lubricating system comprising an axle lubricating device comprising an axle oil sump and a gearbox lubricating device comprising a gearbox oil sump inside the gearbox housing which is a dry sump having an oil storage area which is separate from said gearbox oil sump, a scavenge pump and a first duct configured to retrieve oil from gear box oil sump and to convey the retrieved oil up to the oil storage area, and a main pump and a second duct configured to convey oil from the storage oil area to lubricate the gears of the gearbox.

A differential device is provided with: a ring gear having a tooth row arranged around an axis to mesh with an input gear; an outer case combined with the ring gear and rotatable about the axis; an inner case rotatable about the axis relative to the outer case and having a toothed end with axially projecting dog teeth; a differential gear set supported by the inner case and to be coupled with a pair of axles to allow differential motion between the axles; a clutch member engaging with the outer case and disconnectably connecting with the dog teeth so as to prevent the inner case from rotating relative to the outer case; and perforations penetrating the outer case and opened on an outer face of the outer case, the perforations being so disposed as to expose the dog teeth radially outwardly from the outer case.

An outer-ring lubrication groove pattern formed in an outer-race raceway surface and an inner-race lubrication groove pattern formed in an inner-race raceway surface of a wave generator bearing of a strain wave gearing device are patterns in which linear lubrication grooves having very small widths and depths of several micrometers or less are arranged at fine pitches of several micrometers or less. The inner-race lubrication groove pattern includes a second groove pattern formed in long-axis-side inner-race raceway surface portions to hold the lubricant, and a first groove pattern formed in short-axis-side inner-race raceway surface portions to hold the lubricant and guide the lubricant to the second groove pattern. This configuration improves the contact state between balls and the inner-race and outer-race raceway surfaces of the wave generator bearing, thus reducing the coefficient of friction therebetween.

An internal contact part of a wave generator of a strain wave gearing, a contact part between an externally toothed gear and the wave generator, and tooth surface parts are lubricated by a lubricating fine powder. When the strain wave gearing is in operation, the lubricating fine powder is supplied to the internal contact part and the contact part by a first powder guide that rotates integrally with the wave generator. Having passed through these sections, the lubricating fine powder is supplied to the tooth surface parts by a second powder guide that rotates integrally with the wave generator. Each component part can be reliably lubricated regardless of the orientation of the strain wave gearing during operation.

A differential housing for a differential unit of a vehicle. The differential housing is configured for receiving a differential and an end portion of each of two drive shafts connected by means of the differential. The differential housing has a longitudinal axis. It comprises a peripheral wall which has a substantially tubular shape, and defines an inner space. The differential housing includes at least one hole which extends through the peripheral wall; and a valve mounted in said hole, the valve being configured to allow the passage of oil towards the inner space, and to allow the passage of oil from the inner space towards the outside only below a predetermined valve closing force.

There is provided a work vehicle including a partition wall to keep partition between a first space zone as part of an internal space of the transmission case in which a differential mechanism is located and a second space zone as part of the internal space which is adjacent to the first space zone. An upper space is disposed above the partition wall and configured to allow lubricating oil scooped up from the first space zone by a ring gear to flow in the second space zone. A flow-out path is disposed below the upper space and configured to allow the lubricating oil to flow out of the second space zone to the first space zone.

A variator having at least one roller which runs upon at least one race to transfer drive from one to the other at variable ratio. The variator has a fluid supply for supplying fluid to the race and roller thereby to provide a fluid film by which the roller and the race are separated in use. The roller has a running surface with root means square roughness R.sub.q(roller) and the race having a root means square roughness R.sub.q(race). The variator's specific film thickness is the minimum thickness of the fluid film in normal operation divided by the composite roughness, and is less than 1.0. At least one of the roller and the race has a powder metal surface with a Ra roughness above 0.1 micrometers.