Clutch changeover circuit for non-stage transmission

Abstract

Disclosed is a clutch changeover circuit suitably used for a multi-stage stationary non-stage transmission. Valve bodies of pressure regulating valves (211, 221, 231, 241) are respectively provided with throttle passages (311, 321, 331, 341) communicating therewith in such a manner that hydraulic oil flows to the clutch sides when they are closed, since the sliding of the clutches or damage thereto can occur if pressure regulating valves having good override characteristics are used. Accordingly, at the time of changing over the clutch, since hydraulic oil flows at least by a portion corresponding to the rate of flow of leaking oil, it is possible to prevent the clutches from sliding or becoming damaged while using regulating valves having good override characteristics. In addition, the circuit is provided with common oil passages (301, 302) leading to a plurality of clutches corresponding to speed stages that are not adjacent to each other, and pressure regulating valves (411, 421) and pressure reducing valves (412, 422) that are used jointly for the plurality of stages are provided in these common oil passages, thereby simplifying the circuit configuration by reducing by half the number of these conventionally employed valves.

Dependencies are inferred from the claim text.