# US 2009/0260901 A1 · Electric ground working vehicle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2009/0260901 A1 - Document ID: US20090260901A1 - Status: Published application - Kind: A1 - Application number: 12/426,051 - Filed: 2009-04-17 - Published: 2009-10-22 - Earliest claimed: 2008-04-18 - Assignees: Kanzaki Kokyukoki Mfg. Co., Ltd. - Inventors: Norihiro ISHII; Kengo SASAHARA; Tomoyuki EBIHARA; Kazunari KOGA - Web page: https://patentgrep.com/patent/US20090260901A1 ## CPC - B62D 11/003: {Electric or electronic control systems} - A01D 34/78: electric - B60L 7/26: Controlling the braking effect - B60L 15/2036: {Electric differentials, e.g. for supporting steering vehicles} - B60L 50/61: by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles - B62D 11/04: by means of separate power sources - B60K 7/0007: {the motor being electric} - B60L 2200/40: Working vehicles - B60L 2220/12: Induction machines - B60L 2220/16: DC brushless machines - B60L 2220/44: Wheel Hub motors, i.e. integrated in the wheel hub - B60L 2250/26: by pedal actuation - Y02T 10/62: Hybrid vehicles - Y02T 10/64: Electric machine technologies in electromobility - Y02T 10/70: Energy storage systems for electromobility, e.g. batteries - Y02T 10/7072: Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors - Y02T 10/72: Electric energy management in electromobility - B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M) - A01D: HARVESTING; MOWING - B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES - 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 - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract There is provided an electric ground working vehicle including a left wheel and a right wheel, at least one caster, a working apparatus, an acceleration operating element for performing acceleration instructions, a turn operating element for performing turn instructions, and a control unit. The left wheel and the right wheel are independently driven by left and right electric motors respectively. The control unit controls a regenerative brake driving unit so that electric power is regenerated from the left and right electric motors to an electric power source unit when the acceleration operating element is not operated during traveling to regeneratively brake the left and right wheels. The control unit controls the brake force of the wheels so that the brake force of the wheel at the inside of a turn, among the left wheel and the right wheel, can be made greater than the brake force of the wheel at the outside of a turn when the acceleration operating element is not operated during traveling and turn instructions are inputted from the turn operating element. ## Claims ### Claim 1 An electric ground working vehicle comprising: a left wheel and a right wheel, being main driving wheels, which are independently driven by a left electric motor and a right electric motor respectively; at least one caster, being a steering control wheel, which is freely steerable; a working apparatus driven for ground working; an acceleration operating element for performing acceleration instructions; a turn operating element for performing turn instructions; and a control unit; wherein the control unit controls force applied to the wheels, being the brake force or driving force of the wheels, so that the rotating speed of a wheel at the inside of a turn, of the left wheel and the right wheel, can be made lower than the rotating speed of the wheel at the outside of a turn, when the acceleration operating element is not operated during traveling, and turn instructions are inputted from the turn operating element. ### Claim 2 (depends on 1) The electric ground working vehicle according to claim 1, wherein the control unit controls a regenerative brake driving unit so that electric power is regenerated from the left electric motor and the right electric motor to an electric power source unit when the acceleration operating element is not operated during traveling to regeneratively brake the left wheel and the right wheel, and controls the brake force of the wheels so that the brake force of the wheel at the inside of a turn, of the left wheel and the right wheel, can be greater than the brake force of the wheel at the outside of a turn when the acceleration operating element is not operated during traveling and turn instructions are inputted from the turn operating element. ### Claim 3 (depends on 2) The electric ground working vehicle according to claim 2, wherein the control unit controls the regenerative brake driving unit corresponding to at least one of the left electric motor and the right electric motor so that a turn-inside regenerative brake force obtained from the electric motor corresponding to the wheel at the inside of a turn, of the left wheel and the right wheel, can be made greater than a turn-outside regenerative brake force obtained from the electric motor corresponding to the wheel at the outside of a turn when the acceleration operating element is not operated during traveling and turn instructions are inputted from the turn operating element. ### Claim 4 (depends on 2) The electric ground working vehicle according to claim 2, further comprising: a left friction brake unit and a right friction brake unit which are provided in correspondence with the left wheel and the right wheel, and whose brake forces can be independently controlled; wherein the control unit controls the friction brake units so that a turn-inside friction brake force obtained from the friction brake unit corresponding to the wheel at the inside of a turn, of the left wheel and the right wheel, can be greater than a turn-outside friction brake force obtained from the friction brake unit corresponding to the wheel at the outside of a turn when the acceleration operating element is not operated during traveling and turn instructions are inputted from the turn operating element. ### Claim 5 (depends on 2) The electric ground working vehicle according to claim 2, wherein the control unit controls the brake force of the wheel so that the sum of the brake forces of the left wheel and the right wheel obtained when the acceleration operating element is not operated during traveling and turn instructions are inputted from the turn operating element can be made greater than a moving-straight regenerative brake force obtained from the left electric motor and the right electric motor when the acceleration operating element is not operated during traveling and moving-straight instructions are inputted from the turn operating element. ### Claim 6 (depends on 2) The electric ground working vehicle according to claim 2, further comprising, an initial brake force setting operation unit for discretionally setting the same initial brake forces in the left wheel and the right wheel, including the regenerative brake forces obtained from the left electric motor and the right electric motor when the acceleration operating element is not operated during traveling straight. ### Claim 7 (depends on 6) The electric ground working vehicle according claim 6, wherein if a target brake force of at least one of the left wheel and the right wheel calculated from an initial brake force setting value calculated in response to a signal from the initial brake force setting operation unit, and the steering direction and the steering amount of the turn operating element, is greater than the maximum regenerative brake force that can be generated on at least one of the left wheel and the right wheel according to the chargeable leeway of the electric power source unit, the left friction brake unit and the right friction brake unit provided in correspondence with the left wheel and the right wheel are controlled so that a shortage uncompensated by the maximum regenerative brake force of the target brake force can be compensated by the friction brake force. ### Claim 8 (depends on 6) The electric ground working vehicle according claim 6, wherein if a target brake force of at least one of the left wheel and the right wheel calculated from an initial brake force setting value calculated in response to a signal from the initial brake force setting operation unit, and the steering direction and the steering amount of the turn operating element, is greater than the maximum regenerative brake force that can be generated on at least one of the left wheel and the right wheel according to the chargeable leeway of the electric power source unit, a driver circuit, being the regenerative brake driving unit, is controlled so that at least one of the left electric motor and the right electric motor can generate a reverse torque to cause the electric power source unit to supply a driving electric power to at least one of the left electric motor and the right electric motor, thereby generating the target brake force on the left wheel and the right wheel. ### Claim 9 (depends on 2) The electric ground working vehicle according to claim 2, further comprising: roll angle detecting unit for detecting a roll angle of the vehicle and inputting the detected signal to the control unit; wherein the control unit includes the roll angle correcting unit for correcting the brake forces of the left wheel and the right wheel according to the roll angle so that the vehicle can be turned in the direction corresponding to the direction steered by the turn operating element when the acceleration operating element is not operated during traveling and the roll angle represented by a signal from the roll angle detecting unit is not zero. ### Claim 10 (depends on 1) The electric ground working vehicle according to claim 1, wherein the acceleration operating element is an acceleration pedal and the turn operating element is a steering wheel. ### Claim 11 (depends on 2) The electric ground working vehicle according to claim 2, wherein the acceleration operating element is an acceleration pedal and the turn operating element is a steering wheel. ### Claim 12 (depends on 1) The electric ground working vehicle according to claim 1, wherein the acceleration operating element and the turn operating element are formed by a single common operating element, and the common operating element is moved in other directions, or pushed forward or backward and rotated around an axis, to enable separate functioning as an acceleration operating element and a turn operating element. ### Claim 13 (depends on 2) The electric ground working vehicle according to claim 2, wherein the acceleration operating element and the turn operating element are formed by a single common operating element, and the common operating element is moved in other directions, or pushed forward or backward and rotated around an axis, to enable separate functioning as an acceleration operating element and a turn operating element. ### Claim 14 (depends on 1) The electric ground working vehicle according to claim 1, further comprising: detecting unit for detecting the rotating speeds of the left wheel and the right wheel; wherein the control unit is capable of controlling the rotating speeds and the brake forces of the left wheel and the right wheel and controls the wheel at the outside of a turn, of the left wheel and the right wheel, so that the brake force becomes zero or constant, and controls the wheels so that the inside wheel rotating speed of the wheel at the inside of a turn, of the left wheel and the right wheel, can be made lower than the outside wheel rotating speed calculated from the outside wheel rotating speed of the wheel at the outside of a turn detected by the detecting unit, and the turn instruction value from the turn operating element when the acceleration operating element is not operated during traveling and turn instructions are inputted from the turn operating element. ### Claim 15 (depends on 1) The electric ground working vehicle according to claim 1, further comprising: detecting unit for detecting the rotating speeds of the left and the right wheel; wherein the control unit is capable of controlling the rotating speeds and the brake forces of the left wheel and the right wheel and controls the wheel at the inside of a turn, of the left wheel and the right wheel so that the brake force becomes zero or constant, and controls the wheels so that the outside wheel rotating speed of the wheel at the outside of a turn, of the left wheel and the right wheel can be higher than the inside wheel rotating speed calculated from the inside wheel rotating speed of the wheel at the inside of a turn detected by the detecting unit, and the turn instruction value from the turn operating element when the acceleration operating element is not operated during traveling and turn instructions are inputted from the turn operating element.