| 摘要 |
PURPOSE:To accurately detect an input rotational speed regardless of a speed change shift. CONSTITUTION:In a rotational speed detecting device for an automatic transmission, the first clutch drum 33, rotated with an input shaft 30 in at least all the forward shifts, is arranged in an internal peripheral side of the second clutch drum 37 not rotated in the predetermined forward shift. The second clutch drum 37 is formed of nonmagnetic material and also to arrange an electromagnetic pickup 46, which outputs a signal by changing a magnetic field according to rotation of the first clutch drum 33, in the peripheral side of the second clutch drum 37. Accordingly, since the second clutch drum 37 not acts as a magnetic shield material, a rotational speed of the input shaft 30 can be always and accurately detected through the first clutch drum 33 integrally formed with the input shaft 30. |
