This development project approached the objective of maintaining automatic transmission (“AT”) functionality by focusing on the filtration ratio of the automatic transmission fluid (“ATF”) strainer with respect to contaminants that are primary factors in reducing the operating accuracy of the oil pressure control valve. First, a filter medium was developed that raised the one-pass filtration ratio for contaminants 10 – 40 μm in diameter to twice the ratio achieved by the current nonwoven fabric used. Next, the filter medium was made with pleats so that it would prevent both the increase in pressure loss and the reduction of dust holding capacity in the filtration area required. In order to prevent the pleats from adhering, a lattice-shaped net was bonded to the front of the filter medium, the molded plastic element was clamped inside a plastic case that fits over the top and bottom, the outer edges were vibration welded, and the filter was put in place. The results from application showed that this ATF strainer was able to achieve a 50% increase in the quantity of contaminants that the oil pressure control valve for an AT can tolerate while maintaining its normal operating accuracy.
Article of Honda R&D Technical Review Vol.14 No.2 (123 - 128)