Riding work vehicle

• US 9,783,203 B2
• Filed: 06/24/2015
• Issued: 10/10/2017
• Est. Priority Date: 03/09/2011
• Status: Active Grant

• Current Assignee: Kubota Corporation
• Original Assignee: Kubota Corporation
• Inventors: Koike, Kazuo, Ito, Hirokazu
• Primary Examiner(s): Hilgendorf, Dale W
• Application Number:
  US14/749,155
• Publication Number:
  US 20150289444A1
• Time in Patent Office: 839 Days
• CPC Class Codes: A01D 2101/00 Lawn-mowers
• CPC Class Codes: A01D 34/006 Control or measuring arrangements
• CPC Class Codes: A01D 34/64 mounted on a vehicle, e.g. a tractor, or drawn by an animal or a vehicle A01D34/695 takes precedence
• CPC Class Codes: A01D 34/78 electric
• CPC Class Codes: A01D 69/02 electric
• CPC Class Codes: B60L 1/003 to auxiliary motors, e.g. for pumps, compressors
• CPC Class Codes: B60L 15/2036 Electric differentials, e.g. for supporting steering vehicles
• CPC Class Codes: B60L 2200/40 Working vehicles
• CPC Class Codes: B60L 2220/44 Wheel Hub motors, i.e. integrated in the wheel hub
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/24 Steering angle
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/461 Speed
• CPC Class Codes: B60L 2250/24 by lever actuation
• CPC Class Codes: B60L 2250/26 by pedal actuation
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60W 2300/156 Ridable lawn mowers
• CPC Class Codes: B60W 30/1886 Controlling power supply to auxiliary devices
• CPC Class Codes: H02P 23/14 : Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

The present invention provides a riding work vehicle that includes a vehicle body having a driver seat; a driving wheel unit supporting the vehicle body; a working electric motor that drives a work unit having a work device; an electric motor controller controlling an operation of the working electric motor in a steady mode or a power saving mode in which consumed power is smaller than the steady mode; and a work load evaluator that evaluates load of the working electric motor. In the riding work vehicle, the electric motor controller operates the working electric motor in the power saving mode in a case where the load of the working electric motor evaluated by the work load evaluator is low load lower than a threshold value.

Claims

1. A riding mower comprising:

a vehicle body having a driver seat;

a driving wheel unit supporting the vehicle body;

a mower unit having a rotating blade that performs mowing work;

a working electric motor that drives the rotating blade;

an electric motor controller controlling an operation of the working electric motor in each of;

a steady mode; and

a power saving mode in which consumed power is less than the steady mode; and

a work load evaluator evaluating a load of the working electric motor,

wherein the electric motor controller operates the working electric motor in the power saving mode in a case where the load of the working electric motor is evaluated by the work load evaluator and is determined to be lower than a threshold value, and

wherein the riding mower operates with the following modes of operation;

the power saving mode is maintained for a predetermined time when the load of the working electric motor in lower than the threshold value; and

the working electric motor is instantly switched to the steady mode when the load of the working electric motor is equal to or greater than the threshold value.

2. The riding mower according to claim 1, wherein the work load evaluator derives a load evaluation value by using at least one of:

a supply current value to the working electric motor;

a rotation number of the working electric motor; and

/or

an input parameter indicative of mowing work being performed.

3. The riding mower according to claim 2, further comprising:

a threshold value setter setting the threshold value and being in communication with the work load evaluator.

4. The riding mower according to claim 1, further comprising:

a threshold value setter setting the threshold value and being in communication with the work load evaluator and the mower controller.

5. The riding mower according to claim 4, wherein the power saving mode occurs during at least one of the following conditions:

the vehicle body is in a ceased state;

the riding mower is determined to be traveling without mowing work needing to be performed;

an amount discharged from a discharge outlet of the mowing unit is determined to be substantially zero; and

/or

a mower deck is in an elevated position.

6. The riding mower according to claim 1, wherein the load of the working electric motor evaluated by the work load evaluator is determined to be lower than the threshold value during at least one of the following conditions:

the vehicle body is in a ceased state;

the riding mower is determined to be traveling without mowing work needing to be performed;

an amount discharged from a discharge outlet of the mowing unit is determined to be substantially zero; and

/or

a mower deck is in an elevated position.

7. The riding mower according to claim 1, wherein the threshold value is a predetermined threshold value.

8. The riding mower according to claim 1, wherein the threshold value is computed threshold value.

9. The riding mower according to claim 1, wherein the threshold value is compared to a computed load evaluation value.

10. A riding mower comprising:

a vehicle body;

a driver seat;

drive wheels supporting the vehicle body;

a mower unit having a rotating blade that cuts grass;

an electric motor that drives the rotating blade and is configured to operate in each of;

a power saving mode; and

a higher speed and/or higher torque mode utilized during grass cutting;

a motor controller activating;

the power saving mode when grass is not being cut; and

the higher speed and/or higher torque mode when grass is being cut; and

a plurality of sensors including at least a steering condition sensor and at least a work condition sensor; and

a work load evaluator receiving sensory information from the sensors, evaluating a load of the electric motor and communicating with the motor controller,

wherein the evaluated load of the electric motor is compared to a threshold value in determining whether to activate the power saving mode or the higher speed and/or higher torque mode, and

wherein the power saving mode is maintained for a predetermined time when the load of the electric motor in lower than the threshold value.

11. The riding mower according to claim 10, wherein the work load evaluator derives a load evaluation value by using at least one of:

a supply current value to the electric motor;

a rotation number of the electric motor; and

/or

an input parameter indicative of grass cutting being performed.

12. The riding mower according to claim 11, further comprising:

a threshold value setter setting the threshold value and being in communication with the work load evaluator.

13. The riding mower according to claim 10, further comprising:

a threshold value setter setting the threshold value and being in communication with the work load evaluator and the mower controller.

14. The riding mower according to claim 13, wherein the power saving mode occurs during at least one of the following conditions:

the vehicle body is in a ceased state;

the riding mower is determined to be traveling without grass cutting needing to be performed;

an amount of cut grass discharged from a discharge outlet of the mowing unit is determined to be substantially zero; and

/or

a mower deck is in an elevated position.

15. The riding mower according to claim 10, wherein the load of the electric motor evaluated by the work load evaluator is determined to be lower than the threshold value during at least one of the following conditions:

the vehicle body is in a ceased state;

the riding mower is determined to be traveling without grass cutting needing to be performed;

an amount of cut grass discharged from a discharge outlet of the mowing unit is determined to be substantially zero; and

/or

a mower deck is in an elevated position.

16. The riding mower according claim 10, wherein the threshold value is a predetermined threshold value.

17. The riding mower according to claim 10, wherein the threshold value is one of:

a computed threshold value; and

compared to a computed load evaluation value.

18. The riding mower according to claim 10, wherein the riding mower operates with the following mode of operation:

the working electric motor is instantly switched to the higher speed and/or higher torque mode.

19. A riding mower comprising:

a vehicle body;

drive wheels supporting the vehicle body;

a plurality of sensors;

a mower unit having a rotating blade that cuts grass;

an electric motor that drives the rotating blade and is configured to operate in each of;

a power saving mode; and

a higher speed and/or higher torque mode utilized during grass cutting; and

a controller receiving inputs from the sensors and activating;

the power saving mode so that the electric motor operates for a first predetermined time with less power and less speed than when in the higher speed and/or higher torque mode; and

the higher speed and/or higher torque mode so that the electric motor operates for a second predetermined time with more power and more speed than when in the power saving mode; and

the controller comprising;

a stored or computed threshold value;

a work load evaluator; and

a motor controller;

wherein the controller compares a value to the stored or computed threshold value in determining whether to activate the power saving mode or the higher speed and/or higher torque mode.