Eight-speed automatic transmission and power transmission method thereof

The invention discloses an eight-speed automatic transmission and a power transmission method thereof, and belongs to the field of transmissions. The transmission comprises four groups of planet rowswhich are the first planet row, the second planet row, the third planet row and the fourth planet row in sequence from left to right. Each planet row is provided with a sun gear, a gear ring, a planetcarrier and multiple planet gears. Three overgears are arranged in a novel power transmission scheme of the transmission, the transmission ratio range is wide, the transmission efficiency of the automatic transmission is effectively improved, the fuel economy is improved, tail gas harmful gas emission of vehicles is reduced, the eight-speed automatic transmission can be arranged on the rear drivevehicles, and the power performance of the vehicles is further improved. 本发明公开了一种八速自动变速器及其动力传递方法，属于变速器领域，变速器包括四组行星排，从左往右依次为第一行星排、第二行星排、第三行星排和第四行星排，所述四组行星排均设置有太阳轮、齿圈、行星架及若干个行星轮。本发明变速器的新动力传递方案中包含有3个超速档，且传动比范围广，将有效改善自动变速器的传递效率、提升