AUTOMATIC TRANSMISSION FOR VEHICLE

摘要

In a non-forward range, the same gear position as a forward first gear position is established in a stepped transmission. A hydraulic controller includes a second linear solenoid valve and third linear solenoid valve that respectively supply hydraulic pressure to a second clutch and first brake, and a selector valve that is provided in an oil passage upstream of the second and third linear solenoid valves and that switches between a state where hydraulic pressure is supplied to the oil passage and a state where supply of hydraulic pressure is cut off. When the non-forward range is set or when a vehicle is moving backward, the selector valve cuts off supply of hydraulic pressure to the oil passage. Thus, when there is a failure in the second or third linear solenoid valve, it is possible to suitably establish a gear position wherein the vehicle is not allowed to move backward.

主权项

1. An automatic transmission for a vehicle, the automatic transmission comprising:
a rotating machine; a stepped transmission, the rotating machine and the stepped transmission being provided in series with each other in a power transmission path between a drive source and a wheel, a gear position in which the vehicle is allowed to move backward or a gear position in which the vehicle is not allowed to move backward being established in the stepped transmission in a forward range, the same gear position as the gear position in which the vehicle is allowed to move backward being established in the stepped transmission in a non-forward range; and a hydraulic controller configured to control hydraulic pressure that is supplied to the stepped transmission, the hydraulic controller including an electromagnetic valve and an oil passage switching device, the electromagnetic valve being configured to supply hydraulic pressure to an engagement element for establishing the gear position in which the vehicle is not allowed to move backward in the stepped transmission, the oil passage switching device being provided in an oil passage upstream of the electromagnetic valve, the oil passage switching device being configured to switch between a state where hydraulic pressure is supplied to the oil passage and a state where supply of hydraulic pressure is cut off, the oil passage switching device being configured to, when the non-forward range is set or when the vehicle is moving backward, cut off supply of hydraulic pressure to the oil passage.