Patent ID: 8185284
Filing Date: 2012-05-22
Classification: F16D,F16H

Abstract:
1. A control device of an automatic transmission comprising a rotation transmission mechanism for transmitting the rotation of a prime mover mounted on a vehicle to a transmission mechanism, and an input clutch for controlling to connect and disconnect the rotation transmitted from the rotation transmission mechanism, the control device including a control means that causes the fluid pressure for the input clutch to be reduced, and executes the neutral control of bringing the input clutch in an engagement state into a half-engagement state, in a case where the vehicle is in a stopped state, and the control means executing the in-neutral control of maintaining the half-engagement state of the input clutch during the neutral control, wherein the control device further includes a differential rotation detecting means that detects differential rotation between the input-side engine speed and output-side rotating speed of the rotation transmission mechanism, and wherein the control means causes the fluid pressure for the input clutch to be reduced in a case where the differential rotation detected by the differential rotation detecting means has exceeded a preset differential rotation threshold value in a state where the control for holding the fluid pressure for the input clutch at a fixed pressure is started in order to maintain the half-engagement state of the input clutch during the in-neutral control. wherein the differential rotation detecting means detects as initial differential rotation the differential rotation after the control that holds the fluid pressure for the input clutch at a fixed pressure is started during the in-neutral control, and detects as after-stability differential rotation the differential rotation for every present given period from a point of time where it is determined that the fluid pressure for the input clutch has actually been brought into a stable state on the basis of the execution of the control that holds the fluid pressure for the input clutch at a fixed pressure, and wherein the control means causes the fluid pressure to be reduced in a case where the after-stability differential rotation detected by the differential rotation detecting means has exceeded the differential rotation threshold value, and a subtraction result between the initial differential rotation and the after-stability differential rotation has exceeded a variation threshold value that is preset as a value smaller than the differential rotation threshold value, after it is determined that the fluid pressure for the input clutch has actually been brought into a stable state.