Patent ID: 8538642
Filing Date: 2013-09-17
Classification: F16H

Abstract:
1. A range determination apparatus, comprising: a gear speed change mechanism including a plurality of planetary gears each transmitting an output torque of a drive source and a plurality of friction engagement elements operative to have respective operation states changed to either an engagement state or a disengagement state, the gear speed change mechanism being used with an automatic transmission realizing speed changes with a torque transmission path of the gear speed change mechanism changed by the operation states of the friction engagement elements, and a real shift range determination being performed based on the operation states of the friction engagement elements; oil pressure control means for controlling oil pressures that change the operation states of the friction engagement elements; a plurality of oil pressure detection means for detecting the oil pressures controlled by the oil pressure control means; memory means for storing operation patterns respectively indicative of the operation states of the friction engagement elements; speed change determination means for determining whether or not the automatic transmission is in a speed change state where the operation states of the friction engagement elements are each being changed by the oil pressure control means; and shift range determination means for determining a current shift range, wherein when the automatic transmission is judged by the speed change determination means to not be in the speed change state in which the operation states of the friction engagement elements are each being changed, the shift range determination means determines the current shift range based on the operation patterns stored in the memory means and oil pressure detection results detected by the oil pressure detection means, and wherein when the automatic transmission is judged by the speed change determination means to be in the speed change state in which the operation states of the friction engagement elements are each being changed, the shift range determination means determines the current shift range to be a drive range obtained prior to the speed change state.