# US 9,750,191 B2 · Electro-hydraulic drive system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,750,191 B2 - Document ID: US9750191B2 - Status: Granted - Kind: B2 - Application number: 15/254,674 - Filed: 2016-09-01 - Published: 2016-12-22 - Granted: 2017-09-05 - Earliest claimed: 2012-05-10 - Assignees: Parker-Hannifin Corporation - Applicants: Parker-Hannifin Corporation - Inventors: Jason Scot Richardson; Ryan Schroeder; Victor Connor; Kenneth Jackson - Web page: https://patentgrep.com/patent/US9750191B2 ## CPC - A01D 69/025: {Electric hybrid systems} - A01D 69/03: fluid - B60K 17/105: {Units comprising at least a part of the gearing and a torque-transmitting axle, e.g. transaxles (B60K17/14 takes precedence)} - F01C 1/103: {the two members rotating simultaneously around their respective axes} - F04B 17/03: driven by electric motors - F04C 2/102: {the two members rotating simultaneously around their respective axes} - F04C 15/008: {Prime movers} - F15B 11/17: using two or more pumps - H02K 7/006: {Structural association of a motor or generator with the drive train of a motor vehicle} - H02K 7/1815: {structurally associated with reciprocating piston engines (general aspects of generating sets, e.g. housing, F02B63/04)} - B60Y 2200/223: Ridable lawn mowers - B60Y 2200/90: Vehicles comprising electric prime movers - F04C 2240/40: Electric motor - F15B 2211/20515: Electric motor - F15B 2211/2053: Type of pump - F15B 2211/7058: Rotary output members - A01D: HARVESTING; MOWING - 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 - F01C: ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES (internal-combustion aspects F02B53/00, F02B55/00) - F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F) - F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS - F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - B60Y: INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY ## Abstract Provided is an electro-hydraulic drive system including first and second electro-hydraulic transmissions for driving respective wheels, the transmissions each including an electric motor, a hydraulic pump driven by the electric motor, and a hydraulic motor drive by the hydraulic pump. When used in a turf vehicle, such as a zero-turn-radius mower, the electro-hydraulic drive system operates the wheels independently from an engine of the mower, thereby allowing the mower to be moved without having to start the engine. In this way, power consumption is lowered and total efficiency of the mower is increased. ## Claims ### Claim 1 A mower comprising: an engine; an electro-hydraulic drive system including: a first electro-hydraulic transmission for driving a first wheel, the first electro-hydraulic transmission including a first electric motor, a first hydraulic pump coupled to and driven by the first electric motor, and a first hydraulic motor coupled to and driven by the first hydraulic pump, the hydraulic motor including an output shaft for driving the wheel; and a second electro-hydraulic transmission for driving a second wheel, the second electro-hydraulic transmission including a second electric motor, a second hydraulic pump coupled to and driven by the second electric motor, and a second hydraulic motor coupled to and driven by the second hydraulic pump, the hydraulic motor including an output shaft for driving the wheel, wherein the electro-hydraulic drive system is operable during a normal operating state of the engine and wherein the electro-hydraulic drive system is operable when the engine is in a non-operating state. ### Claim 2 (depends on 1) The mower according to claim 1, further including at least one controller coupled to the first and second electric motors for controlling the first and second electric motors. ### Claim 3 (depends on 2) The mower according to claim 2, further including a storage device coupled to the controller, wherein the storage device is configured to power the first and second electric motors. ### Claim 4 (depends on 3) The mower according to claim 3, wherein the storage device includes at least one battery and/or capacitor. ### Claim 5 (depends on 1) The mower according to claim 1, wherein the first and second hydraulic pumps are gerotor pumps. ### Claim 6 (depends on 1) The mower according to claim 1, wherein the first and second hydraulic motors are gerotor motors. ### Claim 7 (depends on 1) The mower according to claim 1, wherein the first and second electro-hydraulic transmissions additionally include first and second reservoirs respectively for fluid to flow to/from the respective hydraulic pump. ### Claim 8 (depends on 1) The mower according to claim 1, wherein the first and second electro-hydraulic transmissions additionally include first and second pump plates respectively that house the first and second hydraulic pumps respectively. ### Claim 9 (depends on 8) The mower according to claim 8, wherein the first and second electro-hydraulic transmissions additionally include first and second porting plates respectively, each porting plate having a pump mount surface coupled to the respective pump plate and a motor mount surface coupled to an end port plate of the respective hydraulic motor, wherein the porting plates include first and second fluid passages for directing hydraulic fluid between the hydraulic pumps and hydraulic motors. ### Claim 10 (depends on 9) The mower according to claim 9, wherein the pump mount surface of each porting plate includes a path for allowing hydraulic fluid to flow to/from a cavity in the pump mount surface below the hydraulic pump from/to a reservoir. ### Claim 11 (depends on 9) The mower according to claim 9, wherein the first and second electro-hydraulic transmissions additionally include first and second valve plates coupled to the first and second pump plates respectively on sides of the pump plates opposite the porting plates, wherein the valve plates house respective bypass valves for bypassing the electro-hydraulic drive system. ### Claim 12 (depends on 1) The mower according to claim 1, wherein the first and second electric motors include first and second output shafts respectively, and the first and second hydraulic pumps include first and second input shafts respectively, wherein the first and second output shafts are respectively coupled to the first and second input shafts for driving the respective hydraulic pumps. ### Claim 13 (depends on 12) The mower according to claim 12, wherein the first and second electro-hydraulic transmissions additionally include first and second couplers respectively that couple the first and second input shafts to the first and second output shafts respectively. ### Claim 14 A mower including: a frame; a mower deck supported by the frame; an engine mounted to the frame and configured to power the mower deck; an electro-hydraulic drive system including: a first electro-hydraulic transmission for driving a first wheel, the first electro-hydraulic transmission including a first electric motor, a first hydraulic pump coupled to and driven by the first electric motor, and a first hydraulic motor coupled to and driven by the first hydraulic pump, the hydraulic motor including an output shaft for driving the wheel, wherein each of the first hydraulic pump, the first electric motor, and the first hydraulic motor are mounted relative to a first common housing; and a second electro-hydraulic transmission for driving a second wheel, the second electro-hydraulic transmission including a second electric motor, a second hydraulic pump coupled to and driven by the second electric motor, and a second hydraulic motor coupled to and driven by the second hydraulic pump, the hydraulic motor including an output shaft for driving the wheel, wherein each of the second hydraulic pump, the second electric motor, and the second hydraulic motor are mounted relative to a second common housing; and a controller coupled to the first and second electric motors for controlling the first and second motors, wherein the electro-hydraulic drive system is operable during a normal operating state of the engine and wherein the electro-hydraulic drive system is operable when the engine is in a non-operating state. ### Claim 15 (depends on 14) The mower according to claim 14, further including a storage device coupled to the controller, wherein the storage device is configured to power the first and second electric motors. ### Claim 16 (depends on 15) The mower according to claim 15, wherein the electro-hydraulic drive system operates independently from the engine. ### Claim 17 (depends on 15) The mower according to claim 15, further including a generator coupled to the controller and an output shaft of the engine, the generator being configured to charge the storage device. ### Claim 18 (depends on 1) The mower of claim 1, wherein the electro-hydraulic drive system is modular, the first electro-hydraulic transmission being a first module and the second electro-hydraulic transmission being a second module.