Importance

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Abstract

In a continuously-variable-ratio transmission of the toroidal race rolling traction type, each roller is mounted between the opposing disc surfaces in a roller mounting which is displaceable by an hydraulic ram. Each end of the ram has a piston (13 or 14) at the end of the roller mounting sliding in a cylinder (15 or 16). The hydraulic control system has a combined flow divider and pressure control valve (23) which responds to external control forces (C1 or C2) from solenoids to shift the roller mounting. Fluid flow in both hydraulic circuits (P, JJ', L'L, R, T and S, MM', K'K, Q, T) is always equalized by the valve (23). Thus displacement of the spools (S1, S2) away from equilibrium, by restricting inlet and outlet ports (R and S or P and Q), raises the pressure in one ram chamber (16 or 15) and displaces the ram. Moreover, the same pressure tends to return the spools to the equilibrium position. Hydraulic stopping of the ram occurs when either ram chamber port (L' or K') is restricted by a piston approaching its extreme position.

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First Claim