HYDRAULIC CONTROL DEVICE FOR AUTOMATIC TRANSMISSION

摘要

PROBLEM TO BE SOLVED: To provide an orifice having a high silencing effect without increasing the number of kinds of a separate plates and interference of a valve body with a seal part. SOLUTION: A one-way orifice 22 comprises a first hole 16a formed in a separate plate 16 so as to intercommunicate valve bodies 12 and 14 of which a hydraulic circuit 10 consists; and a second hole 18g arranged in the valve body 12 and formed in the bottom 18a of a cup 18 normally-energized in the direction of the separate plate 16 through the force of a spring 20. The second hole 18g comprises a minimum throttle diameter part 18h, consisting of the outer peripheral part of a hole part in such a way that a protrusion part 18c being a conical trapezoidal hole 18b is formed by press-molding in an internal direction from an outer side end part 18e centering around a hole part formed in the central part of the bottom 18a of the cup 18; and a hole part expanded in a comical shape from the minimum throttle diameter part 18h toward an inner side end part 18f by the hole part.