초록 ▼

A control valve system for controlling the operation of a continuously variable belt-driven motor vehicle transmission includes a first hydraulic pump that supplies fluid to the displacement cylinders of the transmission through a main pressure regulating valve and a transmission ratio control valve

A control valve system for controlling the operation of a continuously variable belt-driven motor vehicle transmission includes a first hydraulic pump that supplies fluid to the displacement cylinders of the transmission through a main pressure regulating valve and a transmission ratio control valve as a function of the setting of the manual selector valve and as a function of the torque requirement and speed of the vehicle. The torque converter is supplied with hydraulic fluid by way of a relief valve which comes into operating in the event of failure of an electronic control unit and a decrease in the vehicle speed. A first emergency operation on/off valve transmits torque at converter discharge pressure, by way of a second emergency on/off valve, as emergency operation control pressure to a transmission ratio control valve.

대표청구항 ▼

A hydraulic valve system for controlling a continuously variable drive ratio automotive vehicle transmission adapted to shift continuously between different drive ratios and having first and second control pulleys driveably connected by an endless traction belt, a displacement cylinder associated wi

A hydraulic valve system for controlling a continuously variable drive ratio automotive vehicle transmission adapted to shift continuously between different drive ratios and having first and second control pulleys driveably connected by an endless traction belt, a displacement cylinder associated with each pulley, the location of the belt on each pulley being radially variable in response to hydraulic fluid pressure in the associated cylinder to shift between the drive ratios, comprising: first and second hydraulic fluid pumps; electronic control means for producing an electrical control signal a ratio pressure control valve coupled to the electronic control means for producing ratio control pressure whose magnitude varies in accordance with the control of the electronic control means; a bypass valve means subject to the control of the ratio control pressure for opening and closing communication between the discharge of the first and second pumps when a drive ratio change is required; ratio control valve means subject to the control of the ratio control pressure and hydraulically connected to the discharge of the first pump for selectively opening hydraulic communication between the discharge of the first pump and the first and second displacement cylinders in accordance with the required drive ratio.