Transmission structure

A transmission structure interposed in a transmission path extending from a drive source to traveling wheels, the transmission structure comprising:

• transmission mechanisms which have a plurality of shift gears and a plurality of clutch mechanisms for selecting a desired shift gear from among the plurality of shift gears, and a forward-side clutch mechanism and a reverse-side clutch mechanism which are capable of realizing a forward drive traveling state in which the traveling wheels are driven in a forward direction and a reverse drive traveling state in which the traveling wheels are driven in a reverse direction, respectively;
• a clutch actuator that performs an engagement operation and a disengagement operation of the plurality of clutch mechanisms;
• a continuously variable transmission mechanism that continuously varies rotation power in the plurality of shift gears;
• a gear shift actuator that performs an operation of changing an output of the continuously variable transmission mechanism;
• a traveling state change member selectively operable to a forward position, a neutral position, or a reverse position for determining a traveling direction of a vehicle;
• and
• a control device which operatively controls the clutch actuator and the gear shift actuator,
• wherein the control device
• (1) actuates, in a drive traveling state in which the vehicle traveling direction matches an operation position of the traveling state change member, the clutch actuator so that a clutch mechanism for a shift gear corresponding to the traveling state at that time point is brought to an engaged state, and in addition, the gear shift actuator to obtain a drive rotation speed corresponding to an operation state of the traveling state change member in the shift gear,
• (2) actuates, when the traveling state change member is operated from the forward position or the reverse position to the neutral position, the clutch actuator so that both the forward-side clutch mechanism and the reverse-side clutch mechanism are brought to a disengaged state and a coasting traveling state is realized,
• (3) determines a presumed shift gear corresponding to the coasting traveling state, actuates the clutch actuator so that only one of the clutch mechanisms on a most downstream side in a transmission direction corresponding to the presumed shift gear is brought to a disengaged state and the other clutch mechanisms are brought to an engaged state, and in addition, actuates the gear shift actuator so as to obtain a gear ratio of a continuously variable transmission mechanism which realizes a vehicle speed at that time point with the presumed shift gear, and
• (4) actuates the clutch actuator so that the clutch mechanism on the most downstream side in the transmission direction in the presumed shift gear at the time point is brought to an engaged state when the drive traveling state is resumed from the coasting traveling state to the drive traveling state by an operation of the traveling state change member.

A transmission structure interposed in a transmission path extending from a drive source to traveling wheels, the transmission structure comprising:

• transmission mechanisms which have a plurality of shift gears, and which have a plurality of clutch mechanisms for selecting a desired shift gear from among the plurality of shift gears;
• a clutch actuator that performs engagement and disengagement of the plurality of clutch mechanisms;
• a continuously variable transmission mechanism that continuously varies rotation power in the plurality of shift gears;
• a gear shift actuator that performs an operation of changing the continuously variable transmission mechanism;
• a traveling state change member that is operable by a person;
• and
• the control device that actuates the clutch actuator so as to realize a shift gear corresponding to a vehicle speed, and in addition, actuates the gear shift actuator in response to an operation of the traveling state change member,
• wherein the control device
• (1) actuates, when a power cut-off signal is input in a drive traveling state in a certain shift gear defined based on an operation direction of the traveling state change member and a vehicle speed, the clutch actuator so that only a clutch mechanism on a most downstream side in a transmission direction among the plurality of clutch mechanisms which realize a drive traveling state in the certain shift gear is brought to a disengaged state,
• (2) determines, when the power cut-off signal is valid in a state in which the traveling state change member is operated in a forward or reverse direction, a presumed shift gear which corresponds to a traveling direction corresponding to the operation state of the traveling state change member and which corresponds to a vehicle speed at that time point, actuates the clutch actuator so that only the clutch mechanism on the most downstream side in the transmission direction among the plurality of clutch mechanisms which realize the presumed shift gear is brought to a disengaged state and the other clutch mechanisms are brought to the engaged state, and in addition, actuates the gear shift actuator so that an HST gear ratio which realizes a vehicle speed at that time point in the presumed shift gear is obtained, and
• (3) actuates, when a cancel signal for canceling the power cut-off-signal is input in a state in which the traveling state change member is operated in a forward or reverse direction, the clutch actuator so that the clutch mechanism on the most downstream side in the transmission direction in the presumed shift gear at that time point is brought to an engaged state.

A transmission structure interposed in a transmission path extending from a drive source to traveling wheels, the transmission structure comprising:

• transmission mechanisms that include a forward-side clutch mechanism and a reverse-side clutch mechanism which are capable of realizing a forward drive traveling state in which the traveling wheels are driven in a forward direction and a reverse drive traveling state in which the traveling wheels are driven in a reverse direction, respectively, and a plurality of clutch mechanisms which have a plurality of shift gears and which are used to select a desired shift gear from among the plurality of shift gears;
• a clutch actuator that performs an engagement operation and a disengagement operation of the plurality of clutch mechanisms;
• a continuously variable transmission mechanism that continuously varies rotation power in the plurality of shift gears;
• a gear shift actuator that performs an operation of changing the continuously variable transmission mechanism;
• a traveling state change member that is operable by a person;
• and
• a control device that actuates the clutch actuator so as to realize a shift gear which corresponds to a traveling direction corresponding to a forward-reverse operation of the traveling state change member and which corresponds to a vehicle speed, and in addition, actuates the shift gear actuator in response to a gear shift operation of the traveling state change member,
• wherein the control device
• (1) actuates, when receiving a neutral signal based on a neutral operation shifted from a forward operation or a reverse operation of the traveling state change member, the clutch actuator so that both the forward-side clutch mechanism and the reverse-side clutch mechanism are brought to a disengaged state,
• (2) determines, while the neutral signal is valid, a presumed shift gear corresponding to a vehicle speed at that time point, actuates the clutch actuator so that the disengaged state of the forward-side clutch mechanism and the reverse-side clutch mechanism is maintained and the plurality of clutch mechanisms, other than the forward-side clutch mechanism and the reverse-side clutch mechanism, which realize the presumed shift gear are brought to an engaged state, and in addition, actuates the gear shift actuator so as to obtain an HST gear ratio which realizes the vehicle speed at that time point in the presumed shift gear,
• (3) actuates, when the traveling state change member is operated in the forward direction or the reverse direction, the clutch actuator so that the forward-side clutch mechanism or the reverse-side clutch mechanism corresponding to the operation direction of the traveling state change member is brought to an engaged state in accordance with the operation direction of the traveling state change member.