# US 7,744,499 B2 · Hydro-mechanical transmission > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,744,499 B2 - Document ID: US7744499B2 - Status: Granted - Kind: B2 - Application number: 11/656,818 - Filed: 2007-01-22 - Published: 2008-07-24 - Granted: 2010-06-29 - Earliest claimed: 2007-01-22 - Assignees: Southwest Research Institute - Inventors: Gary Lee Stecklein - Web page: https://patentgrep.com/patent/US7744499B2 ## CPC - B60W 20/40: Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers {(power-up or power-down of the driveline B60W30/192)} - B60K 6/12: by means of a chargeable fluidic accumulator - B60W 10/02: including control of driveline clutches - B60W 10/06: including control of combustion engines - B60W 10/30: including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps - F16H 47/04: the mechanical gearing being of the type with members having orbital motion - F16H 61/4096: with pressure accumulators - F16H 61/462: for achieving a target speed ratio - B60K 2006/126: {the hydraulic accumulator starts the engine} - B60W 20/00: Control systems specially adapted for hybrid vehicles {(hybrid vehicle design, B60K6/00; electric vehicles B60L)} - F16H 61/0403: {Synchronisation before shifting} - F16H 2037/088: {Power-split transmissions with summing differentials, with the input of the CVT connected or connectable to the input shaft} - F16H 2037/0886: {with switching means, e.g. to change ranges} - F16H 2037/106: {with switching means to provide two variator modes or ranges} - F16H 2200/2007: with two sets of orbital gears - F16H 2200/2035: with two engaging means - Y02T 10/62: Hybrid vehicles - B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT - B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES - F16H: GEARING - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A hydro-mechanical transmission system. The system includes an engine having a drive shaft that extends into and supplies power to a gear box having a first and second planetary gear set, wherein the first and second planetary gear set includes a sun with a first ring gear fixed and a carrier coupled to the drive shaft through a double clutch, a hydraulic pump driven by the engine and hydraulically coupled to a hydraulic motor, a low pressure accumulator coupled to the motor and the pump, a high pressure accumulator coupled to the motor and the pump, wherein the hydraulic motor couples to the suns of both planetary gear sets, wherein the engine drives the carrier of the second planetary gear set with the ring of the second planetary gear set coupled to the drive shaft through a double clutch. ## Claims ### Claim 1 A hydro-mechanical transmission system, comprising: an engine having a first shaft that extends into and supplies power to a gear box having a first and second planetary gear sets, wherein the first and second planetary gear sets include coupled suns with a first ring gear fixed and the first gear carrier coupled to a drive shaft through a clutch, a hydraulic pump driven by the engine through a pump shaft and hydraulically coupled to a hydraulic motor, a low pressure accumulator coupled to the motor and the pump, a high pressure accumulator coupled to the motor and the pump, wherein the hydraulic motor is coupled to the suns of both the first and second gears of the planetary gear sets, wherein the engine drives the carrier of the second planetary gear set with the ring of the second planetary gear set coupled to the drive shaft through the clutch. ### Claim 2 (depends on 1) The system of claim 1, wherein the first and second planetary gear sets includes gear ratios that are configured to provide synchronized shifting when the pump to motor displacement ratio is equal to the displacement ratio that exists when the pump is at maximum displacement and the motor is at minimum displacement. ### Claim 3 (depends on 1) The system of claim 1, wherein the system is adapted to provide recovery of brake energy in first gear by taking the pump to zero displacement and taking the motor over center to pump fluid from the low pressure accumulator into the high pressure accumulator. ### Claim 4 (depends on 1) The system of claim 1, wherein the system is adapted to recover brake energy in second gear by taking the pump and motor over center to pump fluid from the low pressure accumulator into the high pressure accumulator. ### Claim 5 (depends on 1) The system of claim 1, wherein the system is adapted to provide acceleration by displacing the motor to provide motive torque. ### Claim 6 (depends on 1) The system of claim 1, wherein the system is adapted to start the engine using the hydraulic pump. ### Claim 7 A method for manufacturing a hydro-mechanical transmission system, comprising: providing an engine having a first shaft that extends into and supplies power to a gear box having a first and second planetary gear sets, wherein the first and second planetary gear sets include coupled suns with a first ring gear fixed and the first gear carrier coupled to a drive shaft through a clutch, providing a hydraulic pump driven by the engine through a pump shaft and hydraulically coupled to a hydraulic motor, providing a low pressure accumulator coupled to the motor and the pump, providing a high pressure accumulator coupled to the motor and the pump, wherein the hydraulic motor is coupled to the suns of both the first and second gears of the planetary gear sets, wherein the engine drives the carrier of the second planetary gear set with the ring of the second planetary gear set coupled to the drive shaft through the clutch. ### Claim 8 (depends on 7) The method of claim 7, wherein the first and second planetary gear sets includes gear ratios that are configured to provide synchronized shifting when the pump to motor displacement ratio is equal to the displacement ratio that exists when the pump is at maximum displacement and the motor is at minimum displacement. ### Claim 9 (depends on 7) The method of claim 7, wherein the system is adapted to provide recovery of brake energy in first gear by taking the pump to zero displacement and taking the motor over center to pump fluid from the low pressure accumulator into the high pressure accumulator. ### Claim 10 (depends on 7) The method of claim 7, wherein the system is adapted to recover brake energy in second gear by taking the pump and motor over center to pump fluid from the low pressure accumulator into the high pressure accumulator. ### Claim 11 (depends on 7) The method of claim 7, wherein the system is adapted to provide acceleration by displacing the motor to provide motive torque. ### Claim 12 (depends on 7) The method of claim 7, wherein the system is adapted to start the engine using the hydraulic pump. ### Claim 13 A method for powering a vehicle, comprising: using a hydro-mechanical transmission system to power the wheels of a vehicle, wherein the hydro-mechanical transmission system comprises an engine having a first shaft that extends into and supplies power to a gear box having a first and second planetary gear sets, wherein the first and second planetary gear set includes coupled suns with a first ring gear fixed and a carrier coupled to a drive shaft through a clutch, a hydraulic pump driven by the engine through a pump shaft and hydraulically coupled to a hydraulic motor, a low pressure accumulator coupled to the motor and the pump, a high pressure accumulator coupled to the motor and the pump, wherein the hydraulic motor is coupled to the suns of both the first and second gears of the planetary gear sets, wherein the engine drives the carrier of the second planetary gear set with the ring of the second planetary gear set coupled to the drive shaft through the clutch. ### Claim 14 (depends on 13) The method of claim 13, wherein the first and second planetary gear sets includes gear ratios that are configured to provide synchronized shifting when the pump to motor displacement ratio is equal to the displacement ratio that exists when the pump is at maximum displacement and the motor is at minimum displacement. ### Claim 15 (depends on 13) The method of claim 13, wherein the system is adapted to provide recovery of brake energy in first gear by taking the pump to zero displacement and taking the motor over center to pump fluid from the low pressure accumulator into the high pressure accumulator. ### Claim 16 (depends on 13) The method of claim 13, wherein the system is adapted to recover brake energy in second gear by taking the pump and motor over center to pump fluid from the low pressure accumulator into the high pressure accumulator. ### Claim 17 (depends on 13) The method of claim 13, wherein the system is adapted to provide acceleration by displacing the motor to provide motive torque. ### Claim 18 (depends on 13) The method of claim 13, wherein the system is adapted to start the engine using the hydraulic pump.