A hydraulic control system for a continuously variable transmission (CVT) includes a pressure regulator subsystem, a selection valve in downstream fluid communication with the pressure regulator subsystem, the selection valve configured to control a flow of pressurized oil from the pressure regulator subsystem to a primary pulley circuit and a secondary pulley circuit, the primary pulley circuit in fluid communication with a primary pulley and the secondary pulley circuit in communication with a secondary pulley, and a ratio control pump disposed in fluid communication between the primary pulley circuit and the secondary pulley circuit, wherein rotation of the ratio control pump in a first direction pumps pressurized oil from the secondary pulley circuit to the primary pulley circuit and rotation of the control pump in a second direction pumps pressurized oil from the primary pulley circuit to the secondary pulley circuit to change a ratio of the CVT.

An object of the present invention is to provide a continuously variable transmission in which a magnitude relationship between a piston area of a primary pulley and a piston area of a secondary pulley is specified. As means for achieving the object, a continuously variable transmission includes: an electric oil pump disposed in an oil path between a piston oil chamber of a primary pulley and a piston oil chamber of a secondary pulley; and a controlling portion configured to control the entry and exit of oil in the piston oil chamber of the primary pulley by the electric oil pump. A piston area of the primary pulley in the continuously variable transmission is smaller than a piston area of the secondary pulley.

A control apparatus of a transmission includes the transmission that is configured to perform shifting operation with use of a control pressure derived from an actuating oil to be supplied to a hydraulic pressure unit. The control apparatus includes a hydraulic pressure supply source, a switcher, a control pressure adjusting valve, an abnormality detector, and a controller. The controller is configured to control the shifting operation of the transmission to keep a revolution speed of an engine, in an abnormal period in which an abnormality of the switcher is detected by the abnormality detector, at a value that is equal to or greater than an abnormal lower limit value. The abnormal lower limit value is higher than a normal lower limit value in a normal period. The normal period is prior to the detection of abnormality of the switcher by the abnormality detector.

A hydraulic control system for a continuously variable transmission (CVT) includes a pressure regulator subsystem, a selection valve in downstream fluid communication with the pressure regulator subsystem, the selection valve configured to control a flow of pressurized oil from the pressure regulator subsystem to a primary pulley circuit and a secondary pulley circuit, the primary pulley circuit in fluid communication with a primary pulley and the secondary pulley circuit in communication with a secondary pulley, and a ratio control pump disposed in fluid communication between the primary pulley circuit and the secondary pulley circuit, wherein rotation of the ratio control pump in a first direction pumps pressurized oil from the secondary pulley circuit to the primary pulley circuit and rotation of the control pump in a second direction pumps pressurized oil from the primary pulley circuit to the secondary pulley circuit to change a ratio of the CVT.

The continuously variable transmission (CVT) assembly includes a CVT including a drive pulley, a driven pulley, and an endless rotatable device coupled between the drive pulley and the driven pulley. The CVT assembly also includes an actuator coupled to the drive pulley. The CVT assembly also includes an angle sensor coupled to the endless rotatable device such that the angle sensor is configured to measure an angular position of the endless rotatable device. The CVT assembly also includes a controller in communication with the actuator and the angle sensor. The controller is programmed to: (a) determine a speed ratio of the CVT based on the angular position of the endless rotatable device; and (b) control the actuator to adjust the clamping force exerted on the drive pulley in response to determining the speed ratio of the CVT.

An object of the present invention is to provide a continuously variable transmission in which a magnitude relationship between a piston area of a primary pulley and a piston area of a secondary pulley is specified. As means for achieving the object, a continuously variable transmission includes: an electric oil pump disposed in an oil path between a piston oil chamber of a primary pulley and a piston oil chamber of a secondary pulley; and a controlling portion configured to control the entry and exit of oil in the piston oil chamber of the primary pulley by the electric oil pump. A piston area of the primary pulley in the continuously variable transmission is smaller than a piston area of the secondary pulley.

A control apparatus of a transmission includes the transmission that is configured to perform shifting operation with use of a control pressure derived from an actuating oil to be supplied to a hydraulic pressure unit. The control apparatus includes a hydraulic pressure supply source, a switcher, a control pressure adjusting valve, an abnormality detector, and a controller. The controller is configured to control the shifting operation of the transmission to keep a revolution speed of an engine, in an abnormal period in which an abnormality of the switcher is detected by the abnormality detector, at a value that is equal to or greater than an abnormal lower limit value. The abnormal lower limit value is higher than a normal lower limit value in a normal period. The normal period is prior to the detection of abnormality of the switcher by the abnormality detector.

The continuously variable transmission (CVT) assembly includes a CVT including a drive pulley, a driven pulley, and an endless rotatable device coupled between the drive pulley and the driven pulley. The CVT assembly also includes an actuator coupled to the drive pulley. The CVT assembly also includes an angle sensor coupled to the endless rotatable device such that the angle sensor is configured to measure an angular position of the endless rotatable device. The CVT assembly also includes a controller in communication with the actuator and the angle sensor. The controller is programmed to: (a) determine a speed ratio of the CVT based on the angular position of the endless rotatable device; and (b) control the actuator to adjust the clamping force exerted on the drive pulley in response to determining the speed ratio of the CVT.

A transmission comprising: a primary pulley; a secondary pulley; a transmission member wound around the primary pulley and the secondary pulley; an oil pump configured to supply oil; a hydraulic control circuit configured to adjust a pressure of the oil supplied from the oil pump to a line pressure which is a source pressure of a primary pulley pressure supplied to the primary pulley and a secondary pulley pressure supplied to the secondary pulley; a line pressure detection unit configured to detect the line pressure; and a controller configured to control the hydraulic control circuit, wherein the controller is configured to select, as a target pulley pressure, a higher one of a target value of the primary pulley pressure and a target value of the secondary pulley pressure, variably set, according to an oil temperature, a target differential pressure including a detection variation of the line pressure detection unit that varies according to the oil temperature, set a target line pressure which is a target value of the line pressure to a total pressure of the target pulley pressure and the target differential pressure, and control the hydraulic control circuit such that the detected line pressure is adjusted to the target line pressure.

A transmission comprising: a primary pulley; a secondary pulley; a transmission member wound around the primary pulley and the secondary pulley; an oil pump configured to supply oil; a hydraulic control circuit configured to adjust a pressure of the oil supplied from the oil pump to a line pressure which is a source pressure of a primary pulley pressure supplied to the primary pulley and a secondary pulley pressure supplied to the secondary pulley; a line pressure detection unit configured to detect the line pressure; and a controller configured to control the hydraulic control circuit, wherein the controller is configured to select, as a target pulley pressure, a higher one of a target value of the primary pulley pressure and a target value of the secondary pulley pressure, variably set, according to an oil temperature, a target differential pressure including a detection variation of the line pressure detection unit that varies according to the oil temperature, set a target line pressure which is a target value of the line pressure to a total pressure of the target pulley pressure and the target differential pressure, and control the hydraulic control circuit such that the detected line pressure is adjusted to the target line pressure.