Transmission structure

A transmission structure that continuously changes reference rotary power of a drive shaft operatively coupled to a drive source and transmits the changed reference rotary power to a travel output shaft defining a vehicle speed, the transmission structure comprising:

• a main transmission unit that has a speed change output device outputting transmission rotary power continuously changed at least between a first-speed stage and a second-speed stage and a planetary gear mechanism combining the reference rotary power and the transmission rotary power and that outputs combined output of the planetary gear mechanism as travel rotary power;
• an auxiliary transmission unit that can change the travel rotary power from the main transmission unit in multiple stages and transmit the changed travel rotary power to the travel output shaft, the auxiliary transmission unit including a low-speed stage transmission path and a high-speed stage transmission path, through which the travel rotary power from the main transmission unit is transmitted to the travel output shaft at a forward-side low-speed gear ratio and a forward-side high-speed gear ratio, respectively, and low-speed stage and high-speed stage clutch mechanisms that respectively engage/disengage the low-speed stage and high-speed stage transmission paths;
• a main speed change manipulation member and an auxiliary speed change manipulation member for manipulating the main transmission unit and the auxiliary transmission unit, respectively;
• and
• a controller, wherein
• the main transmission unit can select between a first-speed stage transmission state and a second-speed stage transmission state, where in the first-speed stage transmission state, a speed of the combined output of the planetary gear mechanism being increased as the transmission rotary power is shifted from the first-speed stage side toward the second-speed stage side;
• and, in the second-speed stage transmission state, the highest speed in the first-speed stage transmission state is set as the lowest speed, and the speed of the combined output of the planetary gear mechanism is increased as the transmission rotary power is shifted from the second-speed stage side to the first-speed stage side,
• the controller controls operation of the auxiliary transmission unit to realize a low-speed stage state by engagement of the low-speed stage clutch mechanism and a high-speed stage state by engagement of the high-speed stage clutch mechanism according to a manipulation of the auxiliary speed change manipulation member, and
• the controller further:
• realizes a first-speed stage transmission state when the vehicle speed in the low-speed stage state does not exceed a low-speed stage switching speed or the vehicle speed in the high-speed stage state does not exceed a high-speed stage switching speed;
• realizes the second-speed stage transmission state when the vehicle speed in the low-speed stage state exceeds the low-speed stage switching speed or the vehicle speed in the high-speed stage state exceeds the high-speed stage switching speed;
• controls operation of the main transmission unit by setting the vehicle speed that is defined by a manipulation position of the main speed change manipulation member as a target vehicle speed for each of the low-speed stage state and the high-speed stage state;
• in the case where a switching manipulation of a gear stage is performed by the auxiliary speed change manipulation member when the travel output shaft is rotationally driven and the vehicle speed is equal to or lower than the low-speed stage switching speed, realizes an idle running state by shifting a pre-switching engagement clutch mechanism, which has been engaged before the switching manipulation by the auxiliary speed change manipulation member, of the low-speed stage and high-speed stage clutch mechanisms, to a disengaged state, and controls operation of the speed change output device to obtain a vehicle speed that corresponds to an actual vehicle speed at the time in a post-switching gear state realized by a post-switching engagement clutch mechanism, which should be engaged after the switching manipulation by the auxiliary speed change manipulation member, of the low-speed stage and high-speed stage clutch mechanisms, during the idle running state;
• and
• thereafter shifts the post-switching engagement clutch mechanism to an engaged state, and, in the post-switching gear state, controls the operation of the speed change output device by setting the vehicle speed that is defined by the manipulation position of the main speed change manipulation member at the time as the target vehicle speed.

A transmission structure that continuously changes reference rotary power of a drive shaft operatively coupled to a drive source and transmits the changed reference rotary power to a travel output shaft defining a vehicle speed, the transmission structure comprising:

• a main transmission unit that has a speed change output device outputting transmission rotary power continuously changed at least between a first-speed stage and a second-speed stage and a planetary gear mechanism combining the reference rotary power and the transmission rotary power and that outputs combined output of the planetary gear mechanism as travel rotary power;
• an auxiliary transmission unit that can change the travel rotary power from the main transmission unit in multiple stages and transmit the changed travel rotary power to the travel output shaft, the auxiliary transmission unit including a low-speed stage transmission path and a high-speed stage transmission path, through which the travel rotary power from the main transmission unit is transmitted to the travel output shaft at a forward-side low-speed gear ratio and a forward-side high-speed gear ratio, respectively, and low-speed stage and high-speed stage clutch mechanisms that respectively engage/disengage the low-speed stage and high-speed stage transmission paths;
• a main speed change manipulation member and an auxiliary speed change manipulation member for manipulating the main transmission unit and the auxiliary transmission unit, respectively;
• and
• a controller, wherein
• the main transmission unit can select between a first-speed stage transmission state and a second-speed stage transmission state, where in the first-speed stage transmission state, a speed of the combined output of the planetary gear mechanism being increased as the transmission rotary power is shifted from the first-speed stage side toward the second-speed stage side;
• and, in the second-speed stage transmission state, the highest speed in the first-speed stage transmission state is set as the lowest speed, and the speed of the combined output of the planetary gear mechanism is increased from the lowest speed as the transmission rotary power is shifted from the second-speed stage side to the first-speed stage side,
• the controller controls operation of the auxiliary transmission unit to realize a low-speed stage state by engagement of the low-speed stage clutch mechanism and a high-speed stage state by engagement of the high-speed stage clutch mechanism according to a manipulation of the auxiliary speed change manipulation member, and
• the controller further:
• realizes the first-speed stage transmission state when the vehicle speed in the low-speed stage state does not exceed a low-speed stage switching speed or the vehicle speed in the high-speed stage state does not exceed a high-speed stage switching speed;
• realizes the second-speed stage transmission state when the vehicle speed in the low-speed stage state exceeds the low-speed stage switching speed or the vehicle speed in the high-speed stage state exceeds the high-speed stage switching speed;
• controls operation of the main transmission unit by setting the vehicle speed that is defined by a manipulation position of the main speed change manipulation member as a target vehicle speed for each of the low-speed stage state and the high-speed stage state;
• further, in the case where a switching manipulation of a gear stage is performed by the auxiliary speed change manipulation member when the travel output shaft is rotationally driven, the vehicle speed is equal to or higher than the low-speed stage switching speed and is equal to or lower than the high-speed stage switching speed, realizes an idle running state by shifting a pre-switching engagement clutch mechanism, which has been engaged before the switching manipulation by the auxiliary speed change manipulation member, of the low-speed stage and high-speed stage clutch mechanisms, to a disengaged state, and switches between the first-speed stage transmission state and the second-speed stage transmission state after controlling operation of the speed change output device to obtain the switching speed in the pre-switching gear state, which has been realized by the pre-switching engagement clutch mechanism, during the idle running state;
• further, controls the operation of the speed change output device to obtain a vehicle speed corresponding to an actual vehicle speed at the time in the post-switching gear state realized by the post-switching engagement clutch mechanism, which should be engaged after the switching manipulation by the auxiliary speed change manipulation member, of the low-speed stage and high-speed stage clutch mechanisms;
• and
• thereafter shifts the post-switching engagement clutch mechanism to an engaged state, and, in the post-switching gear state, controls the operation of the speed change output device by setting the vehicle speed that is defined by the manipulation position of the main speed change manipulation member at the time as the target vehicle speed.

A transmission structure that continuously changes reference rotary power of a drive shaft operatively coupled to a drive source and transmits the changed reference rotary power to a travel output shaft defining a vehicle speed, the transmission structure comprising:

• a main transmission unit that has a speed change output device outputting transmission rotary power continuously changed at least between a first-speed stage and a second-speed stage and a planetary gear mechanism combining the reference rotary power and the transmission rotary power and that outputs combined output of the planetary gear mechanism as travel rotary power;
• an auxiliary transmission unit that can change the travel rotary power from the main transmission unit in multiple stages and transmit the changed travel rotary power to the travel output shaft, the auxiliary transmission unit including a low-speed stage transmission path and a high-speed stage transmission path, through which the travel rotary power from the main transmission unit is transmitted to the travel output shaft at a forward-side low-speed gear ratio and a forward-side high-speed gear ratio, respectively, and low-speed stage and high-speed stage clutch mechanisms that respectively engage/disengage the low-speed stage and high-speed stage transmission paths;
• a main speed change manipulation member and an auxiliary speed change manipulation member for manipulating the main transmission unit and the auxiliary transmission unit, respectively;
• and
• a controller, wherein
• the main transmission unit can select between a first-speed stage transmission state and a second-speed stage transmission state, where in the first-speed stage transmission state, a speed of the combined output of the planetary gear mechanism being increased as the transmission rotary power is shifted from the first-speed stage side toward the second-speed stage side;
• and, in the second-speed stage transmission state, the highest speed in the first-speed stage transmission state is set as the lowest speed, and the speed of the combined output of the planetary gear mechanism is increased from the lowest speed as the transmission rotary power is shifted from the second-speed stage side to the first-speed stage side,
• the controller controls operation of the auxiliary transmission unit to realize a low-speed stage state by engagement of the low-speed stage clutch mechanism and a high-speed stage state by engagement of the high-speed stage clutch mechanism according to a manipulation of the auxiliary speed change manipulation member, and
• the controller further:
• realizes the first-speed stage transmission state when the vehicle speed in the low-speed stage state does not exceed a low-speed stage switching speed or the vehicle speed in the high-speed stage state does not exceed a high-speed stage switching speed;
• realizes the second-speed stage transmission state when the vehicle speed in the low-speed stage state exceeds the low-speed stage switching speed or the vehicle speed in the high-speed stage state exceeds the high-speed stage switching speed;
• then, controls operation of the main transmission unit by setting the vehicle speed that is defined by a manipulation position of the main speed change manipulation member as a target vehicle speed for each of the low-speed stage state and the high-speed stage state;
• further, in the case where a switching manipulation of a gear stage is performed by the auxiliary speed change manipulation member when the travel output shaft is rotationally driven and the vehicle speed is equal to or higher than the high-speed stage switching speed and equal to or lower than a low-speed stage highest speed, realizes an idle running state by shifting a pre-switching engagement clutch mechanism, which has been engaged before the switching manipulation by the auxiliary speed change manipulation member, of the low-speed stage and high-speed stage clutch mechanisms, to a disengaged state, and controls operation of the speed change output device to obtain a vehicle speed that corresponds to an actual vehicle speed at the time in a post-switching gear state realized by a post-switching engagement clutch mechanism, which should be engaged after the switching manipulation by the auxiliary speed change manipulation member, of the low-speed stage and high-speed stage clutch mechanisms, during the idle running state;
• and
• thereafter shifts the post-switching engagement clutch mechanism to an engaged state, and, in the post-switching gear state, controls the operation of the speed change output device by setting the vehicle speed that is defined by the manipulation position of the main speed change manipulation member at the time as the target vehicle speed.

A transmission structure that continuously changes reference rotary power of a drive shaft operatively coupled to a drive source and transmits the changed reference rotary power to a travel output shaft defining a vehicle speed, the transmission structure comprising:

• a main transmission unit that has a speed change output device outputting transmission rotary power continuously changed at least between a first-speed stage and a second-speed stage and a planetary gear mechanism combining the reference rotary power and the transmission rotary power and that outputs combined output of the planetary gear mechanism as travel rotary power;
• an auxiliary transmission unit that can change the travel rotary power from the main transmission unit in multiple stages and transmit the changed travel rotary power to the travel output shaft, the auxiliary transmission unit including a low-speed stage transmission path and a high-speed stage transmission path, through which the travel rotary power from the main transmission unit is transmitted to the travel output shaft at a forward-side low-speed gear ratio and a forward-side high-speed gear ratio, respectively, and low-speed stage and high-speed stage clutch mechanisms that respectively engage/disengage the low-speed stage and high-speed stage transmission paths;
• a main speed change manipulation member and an auxiliary speed change manipulation member for manipulating the main transmission unit and the auxiliary transmission unit, respectively;
• and
• a controller, wherein
• the main transmission unit can select between a first-speed stage transmission state and a second-speed stage transmission state, where in the first-speed stage transmission state, a speed of the combined output of the planetary gear mechanism being increased as the transmission rotary power is shifted from the first-speed stage side toward the second-speed stage side;
• and, in the second-speed stage transmission state, the highest speed in the first-speed stage transmission state is set as the lowest speed, and the speed of the combined output of the planetary gear mechanism is increased from the lowest speed as the transmission rotary power is shifted from the second-speed stage side to the first-speed stage side,
• the controller controls operation of the auxiliary transmission unit to realize a low-speed stage state by engagement of the low-speed stage clutch mechanism and a high-speed stage state by engagement of the high-speed stage clutch mechanism according to a manipulation of the auxiliary speed change manipulation member, and
• the controller further:
• realizes the first-speed stage transmission state when the vehicle speed in the low-speed stage state does not exceed a low-speed stage switching speed or the vehicle speed in the high-speed stage state does not exceed a high-speed stage switching speed;
• realizes the second-speed stage transmission state when the vehicle speed in the low-speed stage state exceeds the low-speed stage switching speed or the vehicle speed in the high-speed stage state exceeds the high-speed stage switching speed;
• then, controls operation of the main transmission unit by setting the vehicle speed that is defined by a manipulation position of the main speed change manipulation member as a target vehicle speed for each of the low-speed stage state and the high-speed stage state;
• further, in the case where a switching manipulation from a high-speed stage to a low-speed stage is performed by the auxiliary speed change manipulation member when the travel output shaft is rotationally driven and the vehicle speed is equal to or higher than the low-speed stage highest speed, controls operation of the speed change output device to reduce the vehicle speed to the low-speed stage highest speed while maintaining an engaged state of the high-speed stage clutch mechanism, realizes an idle running state by shifting the high-speed stage clutch mechanism to a disengaged state after the deceleration, and controls the operation of the speed change output device to obtain a vehicle speed that corresponds to an actual vehicle speed at the time in the low-speed stage state realized by the low-speed stage clutch mechanism during the idle running state;
• and
• thereafter shifts the low-speed stage clutch mechanism to an engaged state, and, in the low-speed stage state, controls the operation of the speed change output device by setting the vehicle speed that is defined by the manipulation position of the main speed change manipulation member at the time as the target vehicle speed.