Narrow range hydromechanical transmission

Claim 2

A power transmission comprising driving means, a planetary gear train drivably connected to said driving means and having first and second sets of planet gears with a common carrier serving as one output of said planetary gear train, one set of planet gears being intermeshed with the other, an input gear driven by said driving means and meshed with the planet gears of said first set, an output gear in mesh with the planet gears of said second set, and a reaction gear in mesh with said first set of said planet gears, a final output means, means for alTernately connecting the output from said carrier and the output from said output gear to said final output means, and means connecting said reaction gear to said driving means through a pair of hydraulic units, one serving as a pump while the other serves as a motor and vice versa, for regulating the torque applied to said planet gears.

Claim 3

The power transmission of claim 1 having clutching means for connecting said final output means to said means connecting said reaction gear to said driving means.

Claim 4

The power transmission of claim 1 wherein during the time each said output gear is engaged, the hydraulic unit serving as a motor at the lowest output speed within the speed range of that output gear decreases its stroke as the output speed increases until said stroke reaches zero and then increases its stroke in the opposite direction as that said hydraulic unit automatically becomes a pump, while the other hydraulic unit, serving as a pump at the lowest output speed within the speed range of that output decreases its speed, and at zero speed becomes a motor with its speed thereafter increasing in the opposite direction as the output speed increases further.

Claim 5

The power transmission of claim 3 wherein at the shift from the output of said output gear to the output of said carrier as the means connected to said final output means, the hydraulic unit which before the shift was serving as a motor immediately thereafter serves as a pump, and vice versa.

Claim 6

The power transmission of claim 4 having means for determining that the ratio of maximum to minimum output speed, at a constant input speed, is the same for each planetary output.

Claim 7

A power transmission comprising input means, output means, and a pair of gear trains for alternately connecting said input means with the output means and providing transmission ranges of different ratios, each train including a planetary gear set with the planet gears of a first set being intermeshed with the planet gears of a second set and a common carrier for both sets of planet gears, said input means being connected to the planet gears of the first planetary gear set through a ring gear, said common carrier comprising an output member of one said gear train, a first sun gear comprising an output member of the other said gear train and meshed with the planet gears of the second planetary gear set, a second sun gear meshed with the planet gears of said first set and serving as the reaction member, a reaction shaft connected to and in driving relation with said second sun gear and a first hydraulic unit connected to and in driving relation with said reaction shaft, a second hydraulic unit connected hydraulically to said first hydraulic unit and in driving relation with said input means, one said hydraulic unit being operated as a pump while the other is operated as a motor and vice versa, the end of a said range of one train overlapping the end of a said range of the other train, and means for alternately connecting and disconnecting the gear trains to the output means at said overlapping ends, whereby power is transmitted alternately from said gear trains to drive the output means through its speed range.

Claim 8

A power transmission comprising input means, output means, and a pair of gear trains for alternately connecting said input means with the output means and providing transmission ranges of different ratios, each train including a planetary gear set with the planet gears of a first set being intermeshed with the planet gears of a second set and a common carrier for both sets of planet gears, said input means being connected to the planet gears of the first planetary gear set through a ring gear, said common carrier comprising an output member of one said gear train, a first sun gear comprising an output member of the other said gear train and meshed with the planet gears of the second planetary gear set, a second sun gear meshed with the planet gears of said first set and serving as the reaction member, a reaction shaft connected to and in driving relation with said second sun gear and a first hydraulic unit connected to and in driving relation with said reaction shaft, a second hydraulic unit connected hydraulically to said first hydraulic unit and in driving relation with said input means, one said hydraulic unit being operated as a pump while the other is operated as a motor and vice versa, the end of a said range of one train overlapping the end of a said range of the other train, and means for alternately connecting and disconnecting the gear trains to the output means at said overlapping ends, whereby power is transmitted alternately from said gear trains to drive the output means through its speed range.

Claim 9

The power transmission of claim 6 having means for determining that the ratio of maximum to minimum output speed, at a constant input speed, is the same in each train.

Claim 10

The power transmission of claim 6 wherein said first hydraulic unit has a variable stroke and said second hydraulic unit has a fixed stroke.

Claim 11

The power transmission of claim 6 having means for alternately connecting and disconnecting said reaction shaft to said output means, said reaction shaft being connected to said output means when both said gear trains are disconnected from said output means, for starting purposes and for reverse operation, with an overlapping shift from the starting combination to one said gear train.

Claim 12

A power transmission comprising an input shaft, AN output shaft, first and second input gears mounted on said input shaft, a planetary gear arrangement having a common carrier carrying first and second sets of planet gears intermeshed with each other, an output sun gear, a reaction sun gear, and a ring gear having integral therewith a gear meshed with said first input gear, said common carrier having integral therewith an output gear, first and second gears mounted on said output shaft, first and second clutches for respectively clutching said first and second gears to said output shaft, said first gear being meshed with said carrier''s output gear, a gear rigidly integral with said sun output gear and meshed with said second gear on said output shaft, a reaction shaft connected to and in driving relation with said reaction sun gear, a first hydraulic unit connected to and in driving relation with said reaction shaft, a second hydraulic unit connected hydraulically to said first hydraulic unit, an auxiliary shaft supporting and in driving relation with said second hydraulic unit, and a gear on said auxiliary shaft meshing with said second input gear, one said hydraulic unit being operated as a pump while the other is operated as a motor and vice versa.

Claim 13

A power transmission comprising an input shaft, AN output shaft, first and second input gears mounted on said input shaft, a planetary gear arrangement having a common carrier carrying first and second sets of planet gears intermeshed with each other, an output sun gear, a reaction sun gear, and a ring gear having integral therewith a gear meshed with said first input gear, said common carrier having integral therewith an output gear, first and second gears mounted on said output shaft, first and second clutches for respectively clutching said first and second gears to said output shaft, said first gear being meshed with said carrier''s output gear, a gear rigidly integral with said sun output gear and meshed with said second gear on said output shaft, a reaction shaft connected to and in driving relation with said reaction sun gear, a first hydraulic unit connected to and in driving relation with said reaction shaft, a second hydraulic unit connected hydraulically to said first hydraulic unit, an auxiliary shaft supporting and in driving relation with said second hydraulic unit, and a gear on said auxiliary shaft meshing with said second input gear, one said hydraulic unit being operated as a pump while the other is operated as a motor and vice versa.

Claim 14

The power transmission of claim 10 wherein the stroke of said first hydraulic unit is variable and the stroke of said second hydraulic unit is fixed.

Claim 15

The power transmission of claim 10 having a third gear on said output shaft, an intermediate gear meshed with said third gear, a gear mounted on said reaction shaft, a second intermediate gear meshed with the said gear mounted on said reaction shaft, and a third clutch for alternately connecting and disconnecting said intermediate gears to each other for starting and for reverse operations, with an overlapping shift from the starting combination to said first clutch.

Claim 16

The power transmission of claim 10 having auxiliary pump means driven by said auxiliary shaft.