Importance

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Abstract

A continuously variable transmission includes a pump (258) driven by an input shaft (256) against a wedge-shaped swashplate (260). Hydraulic fluid pressurized in the pump flows through ports (402) in a pump cylinder block (422) into kidney-shaped slots (406) in the swashplate (260), and from there flows into and pressurizes a series of cylinders (394) in a motor cylinder block (366). The pump and motor exert first and second components of torque on a swashplate (260) in the rotational direction on the input shaft (256), and the hydraulic system pressure in the swashplate slots exerts a third component of torque in the same direction on the swashplate (260). The third torque component is a product of the hydraulic system pressure and the differential area of the two ends of the high pressure slot (406P) at the narrow and thick sides of the wedge-shaped swashplate (260). The swashplate (260) drives an output shaft (266) through an output sleeve (264) pinned to the outside peripheral edge ( 416) of the swashplate (260). The input/output ratio of the transmission is controlled by controlling the tilt angle of the swashplate (260) with a control sleeve (268), coupled at one end to the swashplate (260) through a coupling mechanism (267) and coupled at the other end through a bearing (528) to an axially movable control cylinder (270). The axial position of the control cylinder (270) is hydraulically controlled by a follower valve system (269) which moves the control cylinder (270) to positions uniquely corresponding to positions of a manually or automatically positioned control rod (636).

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First Claim