This disclosure generally relates to an automatic bicycle, particularly to a hydraulic automatic transmission bicycle which can automatically and adaptively change gear ratios. More particularly, this disclosure relates to those hydraulic automatic transmission bicycles which use fluid pressure to change such gear ratios, and which include various hydraulic automatic transmissions which may be provided in various configurations and may operate in various methods and sequences to provide automatic and infinitely variable gear ratios.

A main winch system of a rotary drilling rig includes a main action loop, a pilot control loop, and a feedback control loop. The main action loop includes an engine, a hydraulic pump, a main control valve, a balance valve, a main winch motor, and an oil tank. The pilot control loop includes a pilot handle, a solenoid valve I, a pressure relay, and the main control valve in the main action loop. The feedback control loop includes a solenoid valve II and the hydraulic pump and the main control valve in the main action loop. In response to a lifting action of the pilot handle for the main winch, under the control of a button, the solenoid valve II is energized continuously, and the solenoid valve I is energized and de-energized according to a given rule.

A work vehicle includes a power source, a travel device, a power transmission device, and a control device. The power transmission device includes a hydrostatic continuously variable transmission having a relief valve capable of setting a relief pressure, and is configured to transmit power of the power source to the travel device. The control device includes a relief pressure setting unit configured to set the relief pressure of the relief valve in accordance with a target output value of the travel device.

A gear shifting apparatus for a multi-speed transmission includes: a shifting unit controlling gear shifting by a torque of an actuator; and a parking unit controlling a parking state by the torque of the actuator. In particular, the actuator includes a control motor transmitting a driving torque to driven gears of the shifting and parking units through a drive gear, and the shifting unit includes: a fork slider slidably mounted on a fork rail; a shift fork integrally formed with the fork slider; a finger drum connected to a first driven gear engaged with the drive gear, and having a finger end; and a shift lug that rotates about a lug shaft and includes two lug ends having a different length from each other. The shift lug interacts with the finger end, and has a coupler end coupled with a pocket portion formed at the fork slider.

A gear shifting apparatus for a multi-speed transmission includes: a shifting unit controlling gear shifting by a torque of an actuator; and a parking unit controlling a parking state by the torque of the actuator. In particular, the actuator includes a control motor transmitting a driving torque to driven gears of the shifting and parking units through a drive gear, and the shifting unit includes: a fork slider slidably mounted on a fork rail; a shift fork integrally formed with the fork slider; a finger drum connected to a first driven gear engaged with the drive gear, and having a finger end; and a shift lug that rotates about a lug shaft and includes two lug ends having a different length from each other. The shift lug interacts with the finger end, and has a coupler end coupled with a pocket portion formed at the fork slider.

A gear shifting apparatus for a multi-speed transmission includes: a shifting unit controlling gear shifting by a torque of an actuator; and a parking unit controlling a parking state by the torque of the actuator. In particular, the actuator includes a control motor transmitting a driving torque to a first driven gear of the shifting unit and a second driven gear of the parking unit through a drive gear externally gear-meshed with the driven gears, and the shifting unit includes: a fork slider slidably mounted on a fork rail, a shift fork integrally formed with the fork slider, a cam block connected to the first driven gear engaged with the drive gear and having a cam surface on an exterior circumference for shift-stages, a cam contact pin integrally formed with the fork slider and contacting the cam surface, and a return spring mounted around the fork rail.

A gear shifting apparatus for a multi-speed transmission includes: a shifting unit controlling gear shifting by a torque of an actuator; and a parking unit controlling a parking state by the torque of the actuator. In particular, the actuator includes a control motor transmitting a driving torque to a first driven gear of the shifting unit and a second driven gear of the parking unit through a drive gear externally gear-meshed with the driven gears, and the shifting unit includes: a fork slider slidably mounted on a fork rail, a shift fork integrally formed with the fork slider, a cam block connected to the first driven gear engaged with the drive gear and having a cam surface on an exterior circumference for shift-stages, a cam contact pin integrally formed with the fork slider and contacting the cam surface, and a return spring mounted around the fork rail.

A work vehicle that includes a hydraulic system. The hydraulic system includes a hydraulic motor that generates rotational power for one or more wheels on the work vehicle. A hydraulic pump couples to the hydraulic motor. The hydraulic pump pumps hydraulic fluid to the hydraulic motor. A hydraulic shift control system controls shifting of the hydraulic system. The hydraulic shift control system includes a controller that controls a hydraulic motor volume of the hydraulic motor and a fluid volume pumped by the hydraulic pump to gradually change a speed of the work vehicle during a shift.

A method for controlling a transmission device of a vehicle. The device includes a hydraulic transmission. The displacement of the hydraulic pump is controlled so that it delivers to the n hydraulic motors a constant flow that is proportional to the speed of the wheels rotated by the drive. The displacement control of the hydraulic pump is carried out by a correction constant and a correction variable. The correction variable is determined in real time. The correction constant includes the sum of a theoretical constant and an adjusted constant. The theoretical constant is defined according to the theoretical behaviour of the hydraulic transmission. The adjusted constant is defined and corrected when the vehicle is in predetermined conditions of use, in order to reflect the real state of the vehicle.

A method for controlling a transmission device of a vehicle. The device includes a hydraulic transmission. The displacement of the hydraulic pump is controlled so that it delivers to the n hydraulic motors a constant flow that is proportional to the speed of the wheels rotated by the drive. The displacement control of the hydraulic pump is carried out by a correction constant and a correction variable. The correction variable is determined in real time. The correction constant includes the sum of a theoretical constant and an adjusted constant. The theoretical constant is defined according to the theoretical behaviour of the hydraulic transmission. The adjusted constant is defined and corrected when the vehicle is in predetermined conditions of use, in order to reflect the real state of the vehicle.