Continuously variable hydro-mechanical transmission

1. A transmission for use with a power source and a load, the transmission comprising:

a primary sun gear adapted to be selectively coupled to the power source;

a hydrostatic power unit including a pump coupled to a motor, the pump being adapted to be driven by the power source;

a ring gear driven by the motor;

a secondary sun gear coupled to a first output shaft;

a compound planetary gear carrier coupled to a second output shaft;

a compound planetary gear carried by the compound planetary gear carrier and in engagement with the ring gear and the secondary sun gear;

a load shaft adapted to be coupled to the load; and

a plurality of range gear sets selectively coupled between the load shaft and one of the first or second output shafts;

wherein the first output shaft and the second output shaft are adapted to be selectively coupled to the load.

2. A transmission for use with a power source and a load, the transmission comprising:

a primary sun gear adapted to be selectively coupled to the power source;

a hydrostatic power unit including a pump coupled to a motor, the pump being adapted to be driven by the power source;

a ring gear driven by the motor;

a secondary usn gear coupled to a first output shaft;

a compound planetary gear carrier coupled to a second output shaft;

a compound planetary gear carried by the compound planetary gear carrier and in engagement with the ring gear and the secondary sun gear;

a load shaft adapted to be coupled to the load;

an intermediate shaft; and

a plurality of range gear sets coupled to the intermediate shaft and selectively coupled between the load shaft and at least one of the first output shaft and the second output shaft, wherein the first output shaft and the second output shaft are adapted to be selectively coupled to the load.

3. The transmission of claim 1 , wherein the plurality of range gear sets include:

an A-range output gear coupled to the intermediate shaft and engaged with an A-range input gear mounted on the second output shaft;

a B-range output gear coupled to the intermediate shaft and engaged with a B-range input gear mounted on the first output shaft;

a C-range output gear coupled to the intermediate shaft and engaged with a C-range input gear mounted on the second output shaft;

a D-range output gear coupled to the intermediate shaft and engaged with a D-range input gear mounted on the first output shaft; and

a plurality of range selectors coupled to the intermediate shaft.

4. The transmission of claim 2 , wherein each range selector is a clutch.

5. The transmission of claim 1 , wherein at least two of the range gear sets are engaged for a selected speed.

6. A work vehicle representing a load in the form of motive and output power, the vehicle comprising:

a power source; and

a transmission including a primary sun gear selectively coupled to the power source; a hydrostatic power unit including a pump coupled to a motor, the pump being driven by the power source; a ring gear driven by the motor; a secondary sun gear coupled to a first output shaft; a compound planetary gear carrier coupled to a second output shaft; a compound planetary gear carried by the compound planetary gear carrier and in engagement with the ring gear and the secondary sun gear; and a selectively actuatable forward power train from the power source to the primary sun gear, wherein the first output shaft and the second output shaft are selectively coupled to the load; and further wherein the forward power train includes a pair of gears between the power source and the primary sun gear and at least one clutch for selectively actuating the forward power train.

7. A work vehicle representing a load in the form of motive and output power, the vehicle comprising:

a power source; and

a transmission including a primary sun gear selectively coupled to the power source; a hydrostatic power unit including a pump coupled to a motor, the pump being driven by the power source; a ring gear driven by the motor; a secondary sun gear coupled to a first output shaft; a compound planetary gear carrier coupled to second output shaft; a compound planetary gear carried by the compound planetary gear carrier and in engagement with the ring gear and the secondary sun gear; a load shaft adapted to be coupled to the load; an intermediate shaft; and a plurality of range gear sets coupled to the intermediate shaft and selectively coupled between the load shaft and at least one of the first output shaft and the second output shaft, wherein the first output shaft and the second output shaft are selectively coupled to the load.

8. The work vehicle of claim 7 , wherein the plurality of range gear sets include an A-range output gear coupled to the intermediate shaft and engaged with an A-range input gear mounted on the second output shaft; a B-range output gear coupled to the intermediate shaft and engaged with a B-range input gear mounted on the first output shaft; a C-range output gear coupled to the intermediate shaft and engaged with a C-range input gear mounted on the second output shaft; a D-range output gear coupled to the intermediate shaft and engaged with a D-range input gear mounted on the first output shaft; and a plurality of range selectors coupled to the intermediate shaft.

9. The work vehicle of claim 8 , wherein each range selector is a clutch.

10. The work vehicle of claim 8 , wherein at least two of the range gear sets are engaged for a selected speed.