Patent ID: 7447582
Filing Date: 2008-11-04
Classification: F16H,Y10T

Abstract:
1. An oil pressure control apparatus for an automatic transmission comprising: plural frictional engagement elements capable of establishing plural forward shift stages in a automatic transmission by combinations of engagement and disengagement of the plural frictional engagement elements; and a controller configured to select at least one of the plural frictional engagement elements to be supplied with oil pressure in accordance with one of the combinations of engagement and disengagement of the plural frictional engagement elements and to supply oil pressure to the at least one of the plural frictional engagement elements, the controller comprising: wherein in the shift stage selected by the shift stage selecting means, oil with line pressure is supplied to a first frictional engagement element from among the plural frictional engagement elements and a second frictional engagement element corresponding to the first frictional engagement element from among the plural frictional engagement elements for the shift stage selected by the shift stage selecting means, and wherein in the shift stage selected by the shift stage selecting means, a difference between the output-side rotational speed of the first frictional engagement element and an input-side rotational speed of the second frictional engagement element is a minimum of those between the output-side rotational speed of the first frictional engagement elements for the plural forward shift stages and the input-side rotational speed of the second frictional engagement elements for the plural forward shift stages.