WORK VEHICLE AND METHOD OF CONTROLLING WORK VEHICLE
First Claim
1. A work vehicle, comprising:
- an engine;
a hydraulic pump configured to be driven by the engine;
a work implement configured to be driven by a hydraulic oil discharged from the hydraulic pump;
a travelling apparatus configured to be driven by the engine;
a power transmission configured to transmit a driving force from the engine to the travelling apparatus;
a controller configured to control the power transmission; and
an operating device configured to be operated by an operator,the power transmission includingan input shaft,an output shaft,a gear mechanism having a planetary gear mechanism, the gear mechanism being configured to transmit a rotation of the input shaft to the output shaft,a motor connected to a rotary element of the planetary gear mechanism,a first clutch for switching a transmission path for the driving force in the power transmission into a first mode, anda second clutch for switching the transmission path for the driving force in the power transmission into a second mode,when the transmission path is set in the first mode, the first clutch being configured to be engaged and the second clutch being configured to be disengaged,when the transmission path is set in the second mode, the second clutch being configured to be engaged and the first clutch being configured to be disengaged,in the power transmission, a speed ratio of the output shaft to the input shaft varying when a rotational speed of the motor varies,when a speed ratio parameter corresponding to the speed ratio is a predetermined mode switching threshold, a rotational speed ratio of the motor to the input shaft in the first mode and a rotational speed ratio of the motor to the input shaft in the second mode becoming equal, andthe controller includinga clutch controlling unit configured to switch the transmission path from one to the other of the first and second modes when the speed ratio parameter reaches the mode switching threshold,a trigger operation detecting unit configured to detect whether or not a predetermined operation is performed by the operator, anda timer configured to measure a period of time elapsed from a first point of time at which the transmission path is switched into the other mode,the clutch controlling unit being configured to keep setting the transmission path in the other mode even when the speed ratio parameter again reaches the mode switching threshold until a switching prohibition period expires as long as the elapsed period of time is within the switching prohibition period, the switching prohibition period having a predetermined initial value, andthe trigger operation detecting unit being configured to make the switching prohibition period expire when detecting the predetermined operation in the switching prohibition period.
1 Assignment
0 Petitions
Accused Products
Abstract
A power transmission includes first and second clutches for switching a transmission path for a driving force therein. A clutch controlling unit provided for a work vehicle is configured to switch the transmission path from one to the other of first and second modes when a speed ratio parameter reaches a mode switching threshold. The clutch controlling unit is configured to keep setting the transmission path in the other mode even when the speed ratio parameter again reaches the mode switching threshold until a switching prohibition period having a predetermined initial value expires as long as a period of time elapsed after mode switching is included in the switching prohibition period. A trigger detecting unit provided for the work vehicle is configured to make the switching prohibition period expire when detecting a predetermined operation in the switching prohibition period.
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Citations
14 Claims
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1. A work vehicle, comprising:
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an engine; a hydraulic pump configured to be driven by the engine; a work implement configured to be driven by a hydraulic oil discharged from the hydraulic pump; a travelling apparatus configured to be driven by the engine; a power transmission configured to transmit a driving force from the engine to the travelling apparatus; a controller configured to control the power transmission; and an operating device configured to be operated by an operator, the power transmission including an input shaft, an output shaft, a gear mechanism having a planetary gear mechanism, the gear mechanism being configured to transmit a rotation of the input shaft to the output shaft, a motor connected to a rotary element of the planetary gear mechanism, a first clutch for switching a transmission path for the driving force in the power transmission into a first mode, and a second clutch for switching the transmission path for the driving force in the power transmission into a second mode, when the transmission path is set in the first mode, the first clutch being configured to be engaged and the second clutch being configured to be disengaged, when the transmission path is set in the second mode, the second clutch being configured to be engaged and the first clutch being configured to be disengaged, in the power transmission, a speed ratio of the output shaft to the input shaft varying when a rotational speed of the motor varies, when a speed ratio parameter corresponding to the speed ratio is a predetermined mode switching threshold, a rotational speed ratio of the motor to the input shaft in the first mode and a rotational speed ratio of the motor to the input shaft in the second mode becoming equal, and the controller including a clutch controlling unit configured to switch the transmission path from one to the other of the first and second modes when the speed ratio parameter reaches the mode switching threshold, a trigger operation detecting unit configured to detect whether or not a predetermined operation is performed by the operator, and a timer configured to measure a period of time elapsed from a first point of time at which the transmission path is switched into the other mode, the clutch controlling unit being configured to keep setting the transmission path in the other mode even when the speed ratio parameter again reaches the mode switching threshold until a switching prohibition period expires as long as the elapsed period of time is within the switching prohibition period, the switching prohibition period having a predetermined initial value, and the trigger operation detecting unit being configured to make the switching prohibition period expire when detecting the predetermined operation in the switching prohibition period. - View Dependent Claims (2, 7, 8, 9, 10, 11, 12)
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3. A work vehicle, comprising:
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an engine; a hydraulic pump configured to be driven by the engine; a work implement configured to be driven by a hydraulic oil discharged from the hydraulic pump; a travelling apparatus configured to be driven by the engine; a power transmission configured to transmit a driving force from the engine to the travelling apparatus; and a controller configured to control the power transmission, the power transmission including an input shaft, an output shaft, a gear mechanism having a planetary gear mechanism, the gear mechanism being configured to transmit a rotation of the input shaft to the output shaft, a motor connected to a rotary element of the planetary gear mechanism, a first clutch for switching a transmission path for the driving force in the power transmission into a first mode, and a second clutch for switching the transmission path for the driving force in the power transmission into a second mode, when the transmission path is set in the first mode, the first clutch being configured to be engaged and the second clutch being configured to be disengaged, when the transmission path is set in the second mode, the second clutch being configured to be engaged and the first clutch being configured to be disengaged, in the power transmission, a speed ratio of the output shaft to the input shaft varying when a rotational speed of the motor varies, when a speed ratio parameter corresponding to the speed ratio is a predetermined mode switching threshold, a rotational speed ratio of the motor to the input shaft in the first mode and a rotational speed ratio of the motor to the input shaft in the second mode becoming equal, and the controller including a clutch controlling unit configured to switch the transmission path from one to the other of the first and second modes when the speed ratio parameter reaches the mode switching threshold, a timer configured to measure a period of time elapsed from a first point of time at which the transmission path is switched into the other mode, and a speed ratio variation detecting unit configured to detect whether or not the speed ratio parameter deviates from a third range including the mode switching threshold, the clutch controlling unit being configured to keep setting the transmission path in the other mode even when the speed ratio parameter again reaches the mode switching threshold until a switching prohibition period expires as long as the elapsed period of time is included in the switching prohibition period, the switching prohibition period having a predetermined initial value, and the speed ratio variation detecting unit being configured to make the switching prohibition period expire when detecting deviation of the speed ratio parameter from the third range including the mode switching threshold. - View Dependent Claims (4, 5, 6)
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13. A method of controlling a work vehicle equipped with a power transmission,
the power transmission including an input shaft, an output shaft, a gear mechanism having a planetary gear mechanism, the gear mechanism being configured to transmit a rotation of the input shaft to the output shaft, a motor connected to a rotary element of the planetary gear mechanism, a first clutch for switching a transmission path for a driving force in the power transmission into a first mode, and a second clutch for switching the transmission path for the driving force in the power transmission into a second mode, when the transmission path is set in the first mode, the first clutch being configured to be engaged and the second clutch being configured to be disengaged, when the transmission path is set in the second mode, the second clutch being configured to be engaged and the first clutch being configured to be disengaged, in the power transmission, a speed ratio of the output shaft to the input shaft varying when a rotational speed of the motor varies, when a speed ratio parameter corresponding to the speed ratio is a predetermined mode switching threshold, a rotational speed ratio of the motor to the input shaft in the first mode and a rotational speed ratio of the motor to the input shaft in the second mode becoming equal, and the control method comprising: -
switching the transmission path from one to the other of the first and second modes when the speed ratio parameter reaches the mode switching threshold, detecting whether or not a predetermined operation is performed by an operator, measuring a period of time elapsed from a first point of time at which the transmission path is switched into the other mode, setting the transmission path in the other mode even when the speed ratio parameter again reaches the mode switching threshold until a switching prohibition period expires as long as the elapsed period of time is within the switching prohibition period, the switching prohibition period having a predetermined initial value, and making the switching prohibition period expire when the predetermined operation is detected in the switching prohibition period.
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14. A method of controlling a work vehicle equipped with a power transmission,
the power transmission including an input shaft, an output shaft, a gear mechanism having a planetary gear mechanism, the gear mechanism being configured to transmit a rotation of the input shaft to the output shaft, a motor connected to a rotary element of the planetary gear mechanism, a first clutch for switching a transmission path for a driving force in the power transmission into a first mode, and a second clutch for switching the transmission path for the driving force in the power transmission into a second mode, when the transmission path is set in the first mode, the first clutch being configured to be engaged and the second clutch being configured to be disengaged, when the transmission path is set in the second mode, the second clutch being configured to be engaged and the first clutch being configured to be disengaged, in the power transmission, a speed ratio of the output shaft to the input shaft varying when a rotational speed of the motor varies, when a speed ratio parameter corresponding to the speed ratio is a predetermined mode switching threshold, a rotational speed ratio of the motor to the input shaft in the first mode and a rotational speed ratio of the motor to the input shaft in the second mode becoming equal, and the control method comprising: -
switching the transmission path from one to the other of the first and second modes when the speed ratio parameter reaches the mode switching threshold, measuring a period of time elapsed from a first point of time at which the transmission path is switched into the other mode, detecting whether or not the speed ratio parameter deviates from a predetermined third range including the mode switching threshold, setting the transmission path in the other mode even when the speed ratio parameter again reaches the mode switching threshold until a switching prohibition period expires as long as the elapsed period of time is within the switching prohibition period, the switching prohibition period having a predetermined initial value, and making the switching prohibition period expire when deviation of the speed ratio parameter from the third range including the mode switching threshold is detected.
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Specification