Range-switching device of automatic transmission, and control method of the device
AssigneeToyota Jidosha Kabushiki Kaisha
InventorNaoki Nishimura
Life of this patent
Estimating the term…
Abstract
A range-switching device of an automatic transmission has a control device that executes a fail-safe process of prohibiting the changing to the parking range if a parking load greater than or equal to a predetermined value occurs when the vehicle is at rest.
Claims15
A range-switching device of an automatic transmission for a vehicle that selects a transmission range in the automatic transmission in accordance with need, comprising
- a control device that executes a fail-safe process of prohibiting changing of the transmission range to a parking range when there is a request for changing of the transmission range to the parking range if it is estimated that the changing from the parking range to another range would be impossible on an assumption that the transmission range is switched to the parking range.
A control method of a range-switching device of an automatic transmission for a vehicle that selects a transmission range in the automatic transmission in accordance with need, comprising:
- executing a fail-safe process of prohibiting changing of the transmission range to a parking range when there is a request for changing of the transmission range to the parking range if it is estimated that the changing from the parking range to another range would be impossible on an assumption that the transmission range is switched to the parking range.
A range-switching device of an automatic transmission for a vehicle that selects a transmission range in the automatic transmission in accordance with need, comprising:
- a control device that executes a fail-safe process of prohibiting changing of the transmission range to a parking range if there is a parking load greater than or equal to a predetermined value when the vehicle is at rest;
- a range selection portion for selecting a transmission range;
- a driving device that switches the transmission range to a range selected by the range selection portion;
- a parking lock device that causes an output shaft of the automatic transmission to be in an unrotatable state when the parking range is selected in the range selection portion,
- wherein the control device executes a shift process of controlling the driving device or controlling the parking lock device in order to switch the transmission range to a range selected by the range selection portion or switch the transmission range to an appropriate range in accordance with a state of run of the vehicle;
- and
- wherein in order to execute the fail-safe process, the control device has:
- a load estimation portion that estimates the parking load when the vehicle is at rest;
- a determination portion that determines whether or not the changing to the parking range is allowable by comparing a result of estimation by the load estimation portion with a predetermined threshold value;
- and
- a coping portion that prohibits the changing to the parking range if the determination portion determines that the changing to the parking range is not allowable.
Dependencies are inferred from the claim text.