Patent ID: 6361465
Filing Date: 2002-03-26
Classification: F16H

Abstract:
A control device of an automatic transmission, which comprises a plurality of forward driving gear positions and a backward driving gear position that are achieved by engaging and disengaging a plurality of friction elements and which is capable of changing said plurality of forward driving gear positions by an automatic shift or a manual shift according to driving conditions, said control device of the automatic transmission comprising:(a) a first friction element that is engaged at least at a lowest speed forward driving gear position or at the backward driving gear position; (b) a pressure regulating valve that is connected to an output oil channel connected to a first oil channel connected to said first friction element, a second oil channel supplied with an original pressure, a third oil channel that is drained if the forward driving gear position is designated and that is supplied with a rear range pressure if the backward driving gear position is designated, and a fourth oil channel supplied with an oil pressure for changing pressure regulating state, said pressure regulating valve outputting a rear range pressure to said output oil channel if said third oil channel is supplied with the rear range pressure, outputting an oil pressure regulated to such an extent as not to engage said first friction element to said output oil channel if said third oil channel is drained and said fourth oil channel is not supplied with oil pressure, and outputting an oil pressure regulated according to the oil pressure supplied to said fourth oil channel if said third oil channel is drained and said fourth oil channel is supplied with the oil pressure; (c) a first shift valve that is connected to said fourth oil channel, a fifth oil channel supplied with a control pressure for controlling said pressure regulating valve and a sixth oil channel connected to a timing solenoid valve, said first shift valve supplying a control pressure to said fourth oil channel by connecting said fifth oil channel and said fourth oil channel when said timing solenoid valve is turned off and draining said fourth oil channel when said timing solenoid valve is turned on; (d) a shift control part that keeps said timing solenoid valve on for a predetermined time when the gear position is automatically shifted from a gear position at which said first friction element is unengaged to a gear position at which said first friction element is engaged, and then turns off said timing solenoid valve; and that switches said timing solenoid valve to an OFF state when the gear position is manually shifted from a gear position at which said first friction element is unengaged to a gear position at which said first friction element is engaged; and (e) wherein an oil pressure for engaging said friction element is supplied to said first oil channel from said pressure regulating valve when said control pressure acts on said pressure regulating valve through said fourth oil channel.