Patent ID: 7291078
Filing Date: 2007-11-06
Classification: F16H

Abstract:
1. A gear change control system of a belt-type continuously variable transmission, comprising: I) a movable pulley piston chamber for causing a thrust force to a movable pulley which varies a groove width of each of a primary pulley and a secondary pulley, the movable pulley piston chamber having a double-piston constitution including: II) a communication passage communicating the primary clamp chamber with the secondary clamp chamber, a clamp chamber's applied pressure area on a primary side being substantially equal to a clamp chamber's applied pressure area on a secondary side; III) a gear change control valve for controlling an oil pressure of the cylinder chamber; IV) a clamping force setting valve disposed between an oil pressure source and the communication passage, the clamping force setting valve setting an oil pressure of the clamp chamber; and V) a gear change control section for achieving a certain gear change ratio by outputting an instruction signal to the gear change control valve and the clamping force setting valve in accordance with a sensed traveling state, the gear change control section including: