Planetary gear train of automatic transmission for vehicle

Abstract

A planetary gear train of an automatic transmission for a vehicle may include an input shaft receiving torque of an engine, an output shaft outputting torque of the engine, a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, a first shaft, a second shaft, a third shaft, a fourth shaft directly connected to the input shaft, a fifth shaft selectively connectable to the second shaft, a sixth shaft selectively connectable to the fifth shaft, a seventh shaft selectively connectable to the fourth shaft and the fifth shaft, and an eighth shaft directly connected to the output shaft.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]The present application claims priority to Korean Patent Application No. 10-2016-0032992, filed Mar. 18, 2016, the entire contents of which is incorporated herein for all purposes by this reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to an automatic transmission for a vehicle. More particularly, the present invention relates to a planetary gear train of an automatic transmission for a vehicle that improves power delivery performance and fuel economy by achieving ten forward speed stages with a minimum number of constituent elements being used and improves silent driving of the vehicle by using an operation point positioned at a low engine speed.[0004]2. Description of Related Art[0005]Generally, an automatic transmission achieving more speed stages has been developed to enhance fuel economy and optimize drivability. Recent increases in oil prices are triggering stiff competition in ...

AI Technical Summary

Benefits of technology

The invention provides a planetary gear train for an automatic transmission in a vehicle that has multiple forward and reverse speed stages, resulting in improved power delivery performance and fuel economy. The gear train also improves silent driving of the vehicle by using an operation point positioned at a low rotation speed region of the engine. The gear train maximizes driving efficiency of the engine and improves power delivery performance and fuel consumption.

Problems solved by technology

Recent increases in oil prices are triggering stiff competition in enhancing fuel consumption of a vehicle.

However, in the automatic transmission, as the number of speed stages increase, the number of internal components (particularly, planetary gear sets) increase, and as a result, a length of the transmission increases.

This may deteriorate installability and / or power flow efficiency and may increase production cost, and weight.

In this case, since the length of the automatic transmission increases, mountability may be deteriorated.

In recent planetary gear trains, one planetary gear set is disposed above another planetary gear set, but structures of automatic transmissions to which parallel planetary gear sets is applied are very limited.

However, shift feel may be deteriorated.

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