Hydromechanical steering transmission

Claim 2

A hydromechanical drive and steer transmission having an input, a first output and a second output, and means for coupling said input to said outputs including: a. hydraulic drive means; said hydraulic drive means including a first hydraulic motor and a second hydraulic motor, means coupling said motors to said input, and means for selectively varying the rotational output speed of each said hydraulic motor; means coupling said first motor to said first output; means coupling said second motor to said second output; a steering differential including a first input, a second input and an output; means coupling said first hydraulic motor to said first input of said steering differential; means coupling said second hydraulic motor to said second input of said steering differential; said output of said steering differential providing an average output of said first and second inputs; b. mechanical drive means coupled to said input and including: selective means for selectively coupling said mechAnical drive means to said first output and said second output; and selective means for selectively coupling said output of said steering differential to said mechanical drive means; whereby selective actuation of said selective means in different modes causes said transmission to drive in distinct ranges.

Claim 3

A hydromechanical transmission as defined in claim 1 and wherein said first hydraulic motor and said second hydraulic motor are ball piston pump-motor units.

Claim 4

A hydromechanical trasmission as defined in claim 1, and wherein said steering differential is a planetary set wherein said first input comprises a planetary carrier, said second input is a sun gear and said output is a ring gear.

Claim 5

A hydromechanical transmission as defined in claim 1 wherein said selective means for selectively coupling said mechanical drive means to said first and second outputs includes a plurality of clutch devices whereby actuation of said devices in a first mode causes said transmission to drive solely through said hydraulic drive means in a hydrostatic range, actuation of said devices in a second mode actuates said means for selectively coupling said output of said steering differential and causes said transmission to drive through both said hydraulic drive means and said mechanical drive means in a hydromechanical range, and actuation of said devices in a third mode causes said transmission to operate in a different hydromechanical range.

Claim 6

A hydromechanical drive and steer transmission having an input, a first output shaft and a second output shaft, and means for coupling said input to said output shafts including: a. hydraulic drive means coupled to said input including: a first hydraulic motor, a second hydraulic motor and means for selectively varying the rotational output speed of each said hydraulic motor; means coupling said first motor to said first output shaft, said means including a first planet gear set having a sun gear, a planetary carrier and a ring gear, said first motor being coupled to said sun gear and said output shaft being coupled to said planetary carrier; means coupling said second motor to said second output shaft, said means including a second planet gear set having a sun gear, a planetary carrier and a ring gear, said motor being coupled to said sun gear and said output being coupled to said planetary carrier; a steering differential including a first input, a second input and an output; means coupling said first hydraulic motor to said first input of said steering differential; means coupling said second hydraulic motor to said second input of said steering differential; said output of said steering differential providing an average output of said first and second inputs; b. mechanical drive means coupled to said input and including: a clutch for selectively coupling said output of said steering differential to said mechanical drive means; and plural selective clutch means for coupling said mechanical drive means to said ring gear of said first planet gear set and said ring gear of said second planet gear set; whereby activation of said plural selective clutch means in one mode causes said transmission to drive through said hydraulic means in a hydrostatic first range, activation in a second mode engages said clutch and causes said transmission to drive through both said hydraulic means and said mechanical means in a hydromechanical second range.

Claim 7

A hydromechanical drive and steer transmission having an input, a first output shaft and a second output shaft, and means for coupling said input to said output shafts including: a. hydraulic drive means coupled to said input including: a first hydraulic motor, a second hydraulic motor and means for selectively varying the rotational output speed of each said hydraulic motor; means coupling said first motor to said first output shaft, said means including a first planet gear set having a sun gear, a planetary carrier and a ring gear, said first motor being coupled to said sun gear and said output shaft being coupled to said planetary carrier; means coupling said second motor to said second output shaft, said means including a second planet gear set having a sun gear, a planetary carrier and a ring gear, said motor being coupled to said sun gear and said output being coupled to said planetary carrier; a steering differential including a first input, a second input and an output; means coupling said first hydraulic motor to said first input of said steering differential; means coupling said second hydraulic motor to said second input of said steering differential; said output of said steering differential providing an average output of said first and second inputs; b. mechanical drive means coupled to said input and including: a clutch for selectively coupling said output of said steering differential to said mechanical drive means; and plural selective clutch means for coupling said mechanical drive means to said ring gear of said first planet gear set and said ring gear of said second planet gear set; whereby activation of said plural selective clutch means in one mode causes said transmission to drive through said hydraulic means in a hydrostatic first range, activation in a second mode engages said clutch and causes said transmission to drive through both said hydraulic means and said mechanical means in a hydromechanical second range.

Claim 8

A hydromechanical transmission as defined in claim 5 and wherein said first hydraulic motor and said second hydraulic motor are ball piston pump-motor units.

Claim 9

A hydromechanical transmission as defined in claim 5 and wherein said steering differential is a planetary gear set wherein said first input comprises a planetary carrier, said second input is a sun gear and said output is a ring gear of said gear set.

Claim 10

A hydromechanical transmission as defined in claim 6 wherein said plural clutch means for selectively coupling said mecHanical drive means to said ring gears of said first and second planet gears includes means for coupling said mechanical drive means to said ring gears in a third mode to provide an additional hydromechanical range.

Claim 11

In a multirange hydromechanical steering transmission, the improvement comprising a differential device responsive to two independent speed outputs of a steering range mechanism, said differential device interconnecting said steering range mechanism and the mechanism of an other range to introduce the average speed of said outputs as one of a plurality of inputs to said other range mechanism whereby steering is accomplished solely through said steering range mechanism.

Claim 12

In a multirange hydromechanical steering transmission, the improvement comprising a differential device responsive to two independent speed outputs of a steering range mechanism, said differential device interconnecting said steering range mechanism and the mechanism of an other range to introduce the average speed of said outputs as one of a plurality of inputs to said other range mechanism whereby steering is accomplished solely through said steering range mechanism.

Claim 13

The improvement is a multirange hydromechanical steering transmission of claim 9 wherein said differential is a mechanical differential, and said other range is a higher range than said one range and said average speed is introduced into said second, higher range through a single gear set in said second, higher range mechanism.

Claim 14

The improvement in a multirange hydromechanical steering transmission of claim 10 wherein said first range mechanism includes right and left hydraulic components having variable hydraulic displacement and said second range is a hydromechanical range.

Claim 15

In a multirange hydromechanical steering transmission having power input means; a hydrostatic first range including mechanical input drive means responsive to said power input means, adjustable hydraulic propulsive and steering means responsive to said drive means, two output shaft means responsive to said propulsive and steering means, the speed of each said output shaft means being independently adjustable by said adjustable propulsive and steering means to provide steering; two transmission output devices, one said device being responsive to each said output shaft means of said first range; and a hydromechanical second range including a mechanical input drive means responsive to said power input means, gear set means and output gear means for transmitting second range output to said two transmission output devices; a speed averaging differential device having two input elements and one output element interposed between said first and second ranges with each said input element being connected to a different said output shaft means of said first range and said output element being connected to said gear set means of said second range for transmitting to said second range, for second range operation, a speed that is the average of the two outputs of said adjustable hydraulic propulsive and steering means whereby steering is accomplished in both ranges by adjustment of said first range propulsive and steering means, the output speed of said transmission in first range is a function of said power input means and said hydraulic propulsive and steering means, and the output speed of said transmission in second range is a function of the output of said first range, said power input means, said gear set means and said transmission output devices.

Claim 16

In a multirange hydromechanical steering transmission having power input means; a hydrostatic first range including mechanical input drive means responsive to said power input means, adjustable hydraulic propulsive and steering means responsive to said drive means, two output shaft means responsive to said propulsive and steering means, the speed of each said output shaft means being independently adjustable by said adjustable propulsive and steering means to provide steering; two transmission output devices, one said device being responsive to each said output shaft means of said first range; and a hydromechanical second range including a mechanical input drive means responsive to said power input means, gear set means and output gear means for transmitting second range output to said two transmission output devices; a speed averaging differential device having two input elements and one output element interposed between said first and second ranges with each said input element being connected to a different said output shaft means of said first range and said output element being connected to said gear set means of said second range for transmitting to said second range, for second range operation, a speed that is the average of the two outputs of said adjustable hydraulic propulsive and steering means whereby steering is accomplished in both ranges by adjustment of said first range propulsive and steering means, the output speed of said transmission in first range is a function of said power input means and said hydraulic propulsive and steering means, and the output speed of said transmission in second range is a function of the output of said first range, said power input means, said gear set means and said transmission output devices.