Hydraulic apparatus with axially aligned hydraulic units

Claim 2

Hydraulic apparatus with axially aligned hydraulic units, comprising, in combination, first and second hydraulic units having first and second stator means and first and second rotary means, respectively, said first and second rotary means having a common axis; connecting means having an engaged condition connecting said first and second rotary means for rotation about said common axis so that said first and second hydraulic units are simultaneously operated as pumps when said first rotary means is driven, and as hydraulic motors when a fluid medium under pressure is supplied to said first hydraulic units, and a disengaged condition disconnecting said first and second rotary means so that only said first hydraulic unit operates as pump or motor, respectively; and operating means for placing said connecting means selectively in said engaged and disengaged conditions.

Claim 3

Hydraulic apparatus as claimed in claim 1 comprising a housing enveloping said first and second hydraulic units and said connecting means; and wherein said operating means are partly located outside of said housing.

Claim 4

Hydraulic apparatus as claimed in claim 1 wherein said first and second rotary means have axially aligned first and second shafts having adjacent inner end portions; and wherein said connecting means include coupling means connecting and disconnecting said shaft end portions in said engaged and disengaged conditions, respectively.

Claim 5

Hydraulic apparatus as claimed in claim 3 wherein said coupling means include outer peripheral axially extending coupling projections and recesses on said shaft end portions, and a coupling sleeve having inner axially extending coupLing recesses and projections engaging said coupling recesses and projection of one of said shaft end portions, and engaging also said coupling recesses and projections of the other shaft end portion in said engaged condition for connecting said first and second shafts for rotation while axially aligning said shaft end portions; and comprising first and second bearing means for supporting said first and second shafts spaced from said end portions so that said coupling sleeve functions as a bearing.

Claim 6

Hydraulic apparatus as claimed in claim 4 wherein said operating means are connected with said coupling sleeve for moving the same in axial direction between engaged and disengaged positions, respectively, for connecting and disconnecting said shaft end portions.

Claim 7

Hydraulic apparatus as claimed in claim 3 wherein said coupling means include a coupling sleeve mounted on one of said shaft end portions for axial movement and being connected with the same for rotation in said disengaged condition, and enveloping both said shaft end portions in said engaged condition, and being connected also with the other shaft end portion for rotation in said engaged condition; and wherein said coupling sleeve has a bearing portion supporting the other shaft end portion for rotation so that said shaft end portions are aligned with each other whereby said coupling sleeve performs the function of a bearing.

Claim 8

Hydraulic apparatus as claimed in claim 1 wherein said first and second hydraulic units are first and second axial piston pumps; wherein said first and second rotary means include axially aligned first and second shafts, tiltable swash plates on said first and second shafts, and first and second cylinder and piston means on said first and second shafts; wherein said first and second hydraulic units include valve plate means between said first and second cylinder and piston means, said valve plate means having inlets and outlets for said first and second hydraulic units; wherein said connecting means comprise coupling means for said first and second shafts; and comprising a housing enveloping said first and second hydraulic units and said coupling means.

Claim 9

Hydraulic apparatus as claimed in claim 1 wherein said connecting means include coupling means for connecting and disconnecting said first and second rotary means; wherein said operating means include lever means connected with said coupling means for operating the same; and comprising a housing enveloping said first and second hydraulic units and said coupling means, and having a sealed opening through which said lever means projects for manual operation of said coupling means.

Claim 10

Hydraulic apparatus as claimed in claim 8 wherein at least one of said rotary means includes a shaft; wherein said coupling means is mounted on the other rotary means for axial movement between engaged and disengaged positions; and wherein said operating means include an annular operating means connected with said shaft for rotation and mounted on said shaft for axial movement, means connecting said annular operating means with said coupling means, and means connecting said annular operating means with said lever means so that said coupling means can be operated by said lever means.

Claim 11

Hydraulic apparatus as claimed in claim 1 wherein said first rotary means includes a first shaft adapted to be driven by a prime mover when said first hydraulic unit operates as a pump; wherein said second rotary means includes a second shaft axially aligned with said first shaft and adapted to serve as an output shaft when said second hydraulic unit is operated as a hydraulic motor; and comprising valve means having a control position for hydraulically connecting said first and second hydraulic units when said connecting means is in said disengaged condition so that said first hydraulic unit operating as a pump drives said second hydraulic unit operating as a hydraulic motor whereby said first and second hydraulic units form a hydrostatic Transmission, said valve means having another position for guiding fluid from at least one of said hydraulic units to a consumer outlet.

Claim 12

Hydraulic apparatus as claimed in claim 10 comprising an output shaft means; and a coupling for connecting said second shaft with said output means when said first shaft is driven by the prime mover and said first and second hydraulic unit operate as a hydrostatic transmission.

Claim 13

Hydraulic apparatus as claimed in claim 1 wherein said first rotary means includes a first shaft adapted to be driven by a prime mover so that said first rotary unit operates as a pump; wherein said second rotary means includes a second shaft adapted to serve as an output shaft when said connecting means is in said disengaged condition and said second hydraulic unit operates as a hydraulic motor, and adapted to serve as a drive shaft for said second hydraulic unit operating as a pump when said connecting means is in said engaged condition; comprising valve means and conduit means hydraulically connecting said first and second hydraulic units, said valve means being operable between a first control position in which in said disengaged condition of said connecting means only said first hydraulic unit operates as a pump, a second control position in which in said engaged condition of said connecting means said first and second hydraulic units both operate as pumps, and a third control position hydraulically connecting said first and second units so that in said disengaged condition of said connecting means, said second hydraulic unit operates as a hydraulic motor hydraulically driven by said first unit operating as a pump and forming a hydrostatic transmission with the same.

Claim 14

Hydraulic apparatus as claimed in claim 12 comprising an auxiliary pump and a container for a fluid medium communicating with the low-pressure inlet of said auxiliary pump; and wherein said third control position said valve means hydraulically connect the high-pressure outlet of said auxiliary pump with the input of said first hydraulic unit operating as a pump.

Claim 15

Hydraulic apparatus as claimed in claim 13 wherein said valve means include a first valve having a first position hydraulically connecting in said first control position the output of said first hydraulic unit with a consumer, a second position connecting in said second control position the outlets of both said first and second hydraulic units with the consumer, and a third position connecting in said third control position the outlet of said first hydraulic unit with the input of said second hydraulic unit, and a second valve having a first position connecting in said third control position the output of said auxiliary pump with the output of said second hydraulic unit and with the input of said first hydraulic unit, and a second position connecting in said first and second control positions the inlet of said first hydraulic unit and the outlet of said auxiliary pump with said container.