Power transmission for four-wheel drive vehicle

Claim 2

A power transmission for a four-wheel drive vehicle including a transmission casing arranged to be secured to a cylinder block of a prime mover of the vehicle, a change-speed gearing mounted within said transmission casing and having an input shaft drivingly connected to an output shaft of said prime mover, and an intermediate differential unit assembled within said transmission casing and drivingly connected to an output shaft of said change-speed gearing to be applied with a driving torque from said prime mover through said change-speed gearing for transmitting the driving torque to a first drive shaft for front-wheel drive and to a second drive shaft for rear-wheel drive, said intermediate differential unit being characterized by: a differential casing rotatably mounted within said transmission casing and drivingly connected to the output shaft of said change-speed gearing; a pinion gear rotatably mounted within said differential casing; a plurality of first side gears concentrically mounted within said differential casing for relative rotation and being in meshing engagement with said pinion gear, said first side gears being formed in different diameter and arranged to be drivingly connected to one of said drive shafts; a second side gear rotatably mounted within said differential casing, said second side gear being in meshing engagement with said pinion gear and drivingly connected to the other drive shaft; and means for selectively connecting said first side gears to the one of said drive shafts.

Claim 3

A power transmission as claimed in Claim 1, wherein said pinion gear is integrally formed with a plurality of stepped toothed portions which are respectively meshed with said first side gears.

Claim 4

A power transmission as claimed in Claim 1, wherein the output shaft of said change-speed gearing is in the form of a hollow shaft arranged in surrounding relationship with said second drive shaft, and said first drive shaft is arranged in parallel with the output shaft of said change-speed gearing.

Claim 5

A power transmission as claimed in Claim 3, wherein said differential casing is arranged coaxially with the output shaft of said change-speed gearing.

Claim 6

A power transmi3sion as claimed in Claim 3, wherein said differential casing is arranged in parallel with the output shaft of said change-speed gearing.

Claim 7

A power transmission for a four-wheel drive vehicle equipped with a prime mover at an intermediate portion thereof, said pover transmission including a transmission casing arranged to be secured to a cylinder block of said prime mover, a change-speed gearing mounted within said transmission casing and having an input shaft drivingly connected to an output shaft of said prime mover and an output shaft arranged in parallel with the input shaft, and an intermediate differential unit assembled within said transmission casing and drivingly connected to the output shaft of said change-speed gearing to be applied wi:h a driving torque from said prime mover through said change-speed gearing for distributing the driving torque to a first drive shaft for front-wheel drive and to a second drive shaft for rear-wheel drive, said intermediate differential unit being characterized by: a differential casing rotatably mounted within said transmission casing and drivingly connected to the output shaft of said change-speed gearing; a pair of pinion gears rotatably mounted within said differential casing, said pinion gears each being integrally formed with a plurality of stepped toothed portions; a plurality of first side gears concentrically mounted within said differential casing for relative rotation and being in meshing engagement with the respective toothed portions of said pinion gears, said first side gears being formed in different diameter and arranged to be drivingly connected to one of said drive shafts; a second side gear rotatably mounted within said differential casing, said second side gear being in meshing engagement with a pair of toothed portions of said pinion gears and drivingly connected to the other drive shaft; and a shift mechanism for selectively connecting said first side gears to the one of said drive shafts.

Claim 8

A power transmission for a four-wheel drive vehicle equipped with a prime mover at an intermediate portion thereof, said pover transmission including a transmission casing arranged to be secured to a cylinder block of said prime mover, a change-speed gearing mounted within said transmission casing and having an input shaft drivingly connected to an output shaft of said prime mover and an output shaft arranged in parallel with the input shaft, and an intermediate differential unit assembled within said transmission casing and drivingly connected to the output shaft of said change-speed gearing to be applied wi:h a driving torque from said prime mover through said change-speed gearing for distributing the driving torque to a first drive shaft for front-wheel drive and to a second drive shaft for rear-wheel drive, said intermediate differential unit being characterized by: a differential casing rotatably mounted within said transmission casing and drivingly connected to the output shaft of said change-speed gearing; a pair of pinion gears rotatably mounted within said differential casing, said pinion gears each being integrally formed with a plurality of stepped toothed portions; a plurality of first side gears concentrically mounted within said differential casing for relative rotation and being in meshing engagement with the respective toothed portions of said pinion gears, said first side gears being formed in different diameter and arranged to be drivingly connected to one of said drive shafts; a second side gear rotatably mounted within said differential casing, said second side gear being in meshing engagement with a pair of toothed portions of said pinion gears and drivingly connected to the other drive shaft; and a shift mechanism for selectively connecting said first side gears to the one of said drive shafts.

Claim 9

A power transmission as claimed in Claim 6, wherein said shift mechanism includes a slide shaft axially slidably disposec through said first side gears and drivingly connected to the one of said drive shafts, said slide shaft being airanged to be selectively engaged with said first side gears.

Claim 10

A power transmission as claimed in Claim 6, wherein a restriction mechanism is assembled between said differential casing and said second side gear to restrict excessive relative rotation between said casing and said second side gear.

Claim 11

A power transmission as claimed in Claim 7, wherein said first side cears are arranged to be interconnected by said slide shaft.

Claim 12

A power transmission as claimed in Claim 6, wherein the output shaft of said change-speed gearing is in the form of a hollow shaft arranged in surrounding relationship with said second drive shaft, and wherein said differential casing is arranged in parallel with the output and input shafts of said change-speed gearing.