Apparatus and method for disengaging a clutch after a shift command unless a clutch pedal is in a clutch slipping state

A shift control apparatus for a transmission coupled to a power source, comprising:

• a clutch provided between the power source and the transmission, said clutch including a clutch plate movable between an off-clutch position and an on-clutch position;
• a shift control section for delivering a shift command for shifting a gear to a target gear position determined based on a driving state of the power source;
• a gear shift unit for shifting the gear to the target gear position in response to the shift command;
• a first clutch control section for delivering, in association with the shift command, a first clutch control command representative of a target clutch operating state which varies between an off-clutch state and an on-clutch state;
• a second clutch control section for delivering a second clutch control command in response to an operational position of a clutch pedal, which is operable by a driver, the second clutch control command representing a target clutch operating state which varies between the off-clutch state and the on-clutch state;
• and
• an actuator for switching the clutch between the off-clutch state and the on-clutch state, said actuator being operable in accordance with the one of the first and second clutch control commands which represents the target clutch operating state closer to the off-clutch state,
• wherein said first clutch control section delivers a first clutch stroke command serving as the first clutch control command and representative of a target clutch plate position which varies between the off-clutch position and the on-clutch position,
• said second clutch control section delivers a second clutch stroke command serving as the second clutch control command and representative of a target clutch plate position which varies between the off-clutch position and the on-clutch position in accordance with the operational position of the clutch pedal, and
• said actuator is operable in accordance with the one of the first and second clutch control commands which represents the target clutch plate position closer to the off-clutch position, and
• wherein said actuator includes a movable member coupled to the clutch plate and having first and second pressure-receiving portions,
• said movable member moves in a direction of causing the clutch plate to move toward the off-clutch position, wherein a pressure is applied to at least one of said first and second pressure-receiving portions,
• the clutch includes an urging member which urges the clutch plate toward the on-clutch position, and
• said first and second clutch control sections apply first and second pressures, serving as the first and second clutch stroke commands, to said first and second pressure-receiving portions, respectively.

The shift control apparatus for a transmission coupled to a power source, comprising:

• a clutch provided between the power source and the transmission, said clutch including a clutch plate movable between an off-clutch position and an on-clutch position;
• a shift control section for delivering a shift command for shifting a gear to a target gear position determined based on a driving state of the power source;
• a gear shift unit for shifting the gear to the target gear position in response to the shift command;
• a first clutch control section for delivering, in association with the shift command, a first clutch control command representative of a target clutch operating state which varies between an off-clutch state and an on-clutch state;
• a second clutch control section for delivering a second clutch control command in response to an operational position of a clutch pedal, which is operable by a driver, the second clutch control command representing a target clutch operating state which varies between the off-clutch state and the on-clutch state;
• and
• an actuator for switching the clutch between the off-clutch state and the on-clutch state, said actuator being operable in accordance with the one of the first and second clutch control commands which represents the target clutch operating state closer to the off-clutch state,
• wherein said first clutch control section delivers a first clutch stroke command serving as the first clutch control command and representative of a target clutch plate position which varies between the off-clutch position and the on-clutch position,
• said second clutch control section delivers a second clutch stroke command serving as the second clutch control command and representative of a target clutch plate position which varies between the off-clutch position and the on-clutch position in accordance with the operational position of the clutch pedal, and
• said actuator is operable in accordance with the one of the first and second clutch control commands which represents the target clutch plate position closer to the off-clutch position, and
• wherein said first clutch control section includes a pressurized air source, a switching valve interposed in an air passage through which the pressurized air source is connected with a first pressure-receiving portion of the actuator, and a switching valve actuating means for switching said switching valve between a communicating position where said first pressure-receiving portion is communicated with said pressurized air source and a shut-off position where communication between said first pressure-receiving portion and said pressurized air source is prohibited,
• said pressurized air source supplies said first pressure-receiving portion with pressurized air serving as the first clutch stroke command when said switching valve is in the communicating position, and
• said second clutch control section includes a hydraulic source for generating a hydraulic pressure which varies depending on the operational position of the clutch pedal, and applies a hydraulic pressure serving as a second clutch stroke command to a second pressure-receiving portion of the actuator.

A shift control method for controlling a transmission coupled to a power source via a clutch whose operating state is variable between an on-clutch state and an off-clutch state in response to a driver's clutch pedal manipulation, comprising:

• (a) judging whether an operational position of the clutch pedal falls within either of an off-clutch region and an on-clutch region when a shift command for instructing a gear shift is generated;
• (b) actuating the clutch to establish the off-clutch state when the step (a) judges that the operational position of the clutch pedal falls within either of the off-clutch region and the on-clutch region;
• (c) automatically executing the gear shift in the transmission in accordance with the shift command after the off-clutch state is established;
• and
• (d) actuating the clutch to establish the on-clutch state after the automatic gear shifting is completed.