Automatic transmission for vehicle

摘要

A vehicle automatic transmission of a multistage type includes multiple engagement elements having an engagement state switched by an oil pressure to selectively establish a plurality of shift stages based on a combination of engagement and release of the multiple engagement elements according to an oil pressure supplied from a hydraulic circuit, each of the shift stages being established by engagement of two or more engagement elements of the multiple engagement elements, at least one of the multiple engagement elements being a normally closed engagement element engaged when no oil pressure is supplied from the hydraulic circuit, and the normally closed engagement element being a meshing engagement element.

主权项

1. A vehicle automatic transmission comprising:
multiple engagement elements including an engagement state switched by an oil pressure to selectively establish a plurality of shift stages based on a combination of engagement and release of the multiple engagement elements according to an oil pressure supplied from a hydraulic circuit, each of the shift stages being established by engagement of two or more engagement elements of the multiple engagement elements, at least one of the multiple engagement elements being a normally closed engagement element engaged when no oil pressure is supplied from the hydraulic circuit, and the normally closed engagement element being a meshing engagement element, wherein when a first shift stage including a largest shift ratio of forward shift stages is established in the automatic transmission, at least one of the multiple engagement elements engaged is the normally closed engagement element, and at least one of the multiple engagement elements engaged is a normally opened engagement element released when no oil pressure is supplied from the hydraulic circuit, and wherein two meshing brakes are included as the normally closed engagement elements, and rotating elements fixed to a non-rotating member by engagement of the respective meshing brakes are directly or indirectly coupled to an output rotating member of the automatic transmission.