Continuously variable transmission and its hydraulic pressure control method
AssigneesJATCO Ltd, Nissan Motor Co., Ltd.
InventorsSeiichiro Takahashi, Takashi Eguchi, Tomohiro Utagawa, Yuta Ishinabe, Tetsuya Izumi, Takahiro Kobayashi
Life of this patent
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Abstract
A transmission controller determines whether a shift returning to low, changing a speed ratio of a continuously variable transmission to the lowest when a vehicle decelerates, is being performed or not, calculates a primary pressure measured lower limit value at which a belt begins to slip actually, based on a deceleration of the vehicle and the speed ratio of the continuously variable transmission, and sets a lower limit value of a target value of the primary pressure during the shift returning to low as the primary pressure measured lower limit value.
Claims9
A continuously variable transmission that includes a primary pulley, a secondary pulley, and a belt wound therebetween, and that decides a pulley thrusting force by a primary pressure supplied to the primary pulley and a secondary pressure supplied to the secondary pulley, the continuously variable transmission comprising:
- a unit for determining a shift returning to low configured to determine whether the shift returning to low, changing a speed ratio of the continuously variable transmission to lowest when a vehicle decelerates, is being performed or not;
- and
- the unit for computing a measured lower limit value configured to calculate a primary pressure measured lower limit value at which the belt begins to slip actually, based on a deceleration of the vehicle and the speed ratio of the continuously variable transmission,
- wherein a lower limit value of a target value of the primary pressure during the shift returning to low is set as the primary pressure measured lower limit value.
A hydraulic pressure control method of a continuously variable transmission that includes a primary pulley, a secondary pulley, and a belt wound therebetween, and that decides a pulley thrusting force by a primary pressure supplied to the primary pulley and a secondary pressure supplied to the secondary pulley, the hydraulic pressure control method comprising:
- determining whether a shift returning to low, changing a speed ratio of the continuously variable transmission to lowest when a vehicle decelerates, is being performed or not;
- calculating a primary pressure measured lower limit value at which the belt begins to slip actually, based on a deceleration of the vehicle and the speed ratio of the continuously variable transmission;
- and
- setting a lower limit value of a target value of the primary pressure during the shift returning to low as the primary pressure measured lower limit value.
A continuously variable transmission that includes a primary pulley, a secondary pulley, and a belt wound therebetween, and that decides a pulley thrusting force by a primary pressure supplied to the primary pulley and a secondary pressure supplied to the secondary pulley, the continuously variable transmission comprising:
- means for determining a shift returning to low that determines whether the shift returning to low, changing a speed ratio of the continuously variable transmission to lowest when a vehicle decelerates, is being performed or not;
- and
- means for computing a measured lower limit value that calculates a primary pressure measured lower limit value at which the belt begins to slip actually, based on a deceleration of the vehicle and the speed ratio of the continuously variable transmission,
- wherein a lower limit value of a target value of the primary pressure during the shift returning to low is set as the primary pressure measured lower limit value.
Dependencies are inferred from the claim text.