A method of controlling an automatic transmission is provided. The automatic transmission includes first and second frictional engageable elements and a hydraulic mechanism. The method includes controlling a first hydraulic pressure control valve of the first element to adjust hydraulic pressure to a given value in a first period in response to the gear shift command and increase the hydraulic pressure until first friction plates engaged in a second period, and a second hydraulic pressure control valve of the second element to pre-charge in response to the gear shift command, maintain the hydraulic pressure at a lower value than a highest target value immediately after the pre-charging, and increase the hydraulic pressure until second friction plates engaged immediately after the maintaining the pressure, a time length of the first period being shorter than a time length between a start of the pre-charging and a start of the increasing the pressure.

A method of controlling an automatic transmission is provided. The automatic transmission includes a piston having first and second surfaces opposite from each other, friction plates, engaging and disengaging hydraulic pressure chambers for supplying/discharging hydraulic pressure and directing the piston to push the friction plates to be engaged and disengaged, a hydraulic pressure control valve for supplying/discharging hydraulic pressure to/from the chambers, and first and second oil paths communicating the valve with the chambers. The second surface has a larger area for receiving hydraulic pressure than the first surface. The method includes controlling the disengaged friction plates to be engaged by adjusting the hydraulic pressure to a first pressure in a first period in response to a gear shift command and adjusting the hydraulic pressure to a second pressure in a second period. The first pressure is changed depending on a state of the automatic transmission.

A method of controlling an automatic transmission is provided. The automatic transmission includes a piston having first and second surfaces opposite from each other, friction plates, engaging and disengaging hydraulic pressure chambers for supplying hydraulic pressure and directing the piston to push the friction plates to be engaged and disengaged, a hydraulic pressure control valve for supplying and discharging hydraulic pressure to and from the chambers, and first and second oil paths communicating the valve with the chambers. The second surface has a larger area for receiving hydraulic pressure than that of the first surface. The method includes controlling the friction plates to change from the disengaged state to the engaged state. Controlling the friction plates includes adjusting the hydraulic pressure to a first instruction pressure in a first period in response to a gear shift command, and to a second instruction pressure in a second period.

A transmission structure of the present invention causes, during a period from a time point when a rotational speed of a drive rotational power reaches a predetermined first/second speed stage shift-up start speed until a first/second speed stage shift-up end time point, one of an input-side clutch mechanism pair and an output-side clutch mechanism pair to be in a double transmitting state, and causes, in the double transmitting state, a first clutch mechanism and a second clutch mechanism of the other one of the input-side clutch mechanism pair and the output-side clutch mechanism pair to be shifted to a disengagement sate and an engagement state, respectively, while having frictional plate slid.

The invention relates to a shifting device for a motor vehicle transmission, comprising a first coupling component, a second coupling component rotatable about a transmission axis (A), an inner friction ring which has a conical surface on a radially outer face, an outer friction ring which has a conical surface on a radially inner face, and an intermediate friction ring which comprises a friction cone and is connected to the second coupling component for joint rotation with and for axial displacement with respect to the second coupling component, whilst the inner friction ring and the outer friction ring are connected to the first coupling component for joint rotation with and for axial displacement with respect to the first coupling component. The friction cone extends between the conical surfaces of the inner friction ring and outer friction ring, the coupling components being decoupled in the rotation direction in an axial starting position of the outer friction ring and being coupled in a frictional fit in the rotation direction in an axial frictional fit position of the outer friction ring. The intermediate friction ring has a C-shaped ring cross section extending peripherally in the circumferential direction, comprising a radially outer linear cone limb which forms the friction cone and comprises two substantially parallel conical friction surfaces, and comprising a radially inner linear axial limb which is integrally connected to the cone limb by a radial web.

A shift power transmission apparatus of a tractor that has a small up-down width or a small transverse width and a short front-rear length. A shift output unit is located further toward a vehicle rear side than a combined planetary power transmission unit. A planetary unit output axis and a shift unit input axis are coaxial with each other. A power transmission unit, that transmits motive power from an engine to a continuously variable transmission unit and the combined planetary power transmission unit, includes a rotary power transmission shaft, a pump transmission unit and a planetary transmission unit, the rotary power transmission shaft being interlockingly joined to an output shaft of the engine and extending in a direction along a vehicle front-rear direction, the pump transmission unit being configured to input motive power of the rotary power transmission shaft to the continuously variable transmission unit, and the planetary transmission unit being configured to input motive power of the rotary power transmission shaft to the combined planetary power transmission unit.

In a release mechanism of a brake device used in a power transmission process, a motor supplies power, an output shaft of the motor is connected to the brake device, the brake device is formed by at least one friction disc and a brake disc, and a lining is installed on a side of the brake disc facing the friction disc, and a side is acted by an elastic member and attached with the friction disc to produce a braking effect. The release mechanism is connected to the brake device and capable of eliminating the braking effect of the brake device when needed, so that a machine can be operated to complete a stroke to improve the safety of use.

An automatic transmission includes a clutch having a drum section, a hub, a friction plate, a piston that presses the friction plate, a hydraulic chamber to which hydraulic oil is supplied to urge the piston in a direction toward the friction plate, and a cancellation chamber to which hydraulic oil is supplied to cancel a centrifugal hydraulic pressure applied to the hydraulic oil in the hydraulic chamber, and the piston is interposed between the hydraulic chamber and the cancellation chamber. The drum section includes communication passages that extend in a radial direction and respectively communicate with the hydraulic chamber and the cancellation chamber. Of the communication passages, in the communication passage that communicates with the cancellation chamber, an adjustment member is provided at an end portion on a radially inner side, and can adjust an atmospheric air release position of the communication passage in the radial direction.

A method of controlling an automatic transmission is provided. The automatic transmission includes a piston having first and second surfaces opposite from each other, friction plates, engaging and disengaging hydraulic pressure chambers for supplying and discharging hydraulic pressure and directing the piston to push the friction plates to be engaged and disengaged, a hydraulic pressure control valve for supplying and discharging hydraulic pressure to and from the chambers, first and second oil paths communicating the valve with the chambers, and a pressure reducing valve disposed in the second oil path and for preventing hydraulic pressure of the disengaging hydraulic pressure chamber from exceeding a given set pressure. The second surface has a larger area for receiving hydraulic pressure than an area of the first surface for receiving hydraulic pressure. The method includes changing the given set pressure according to information regarding a state of the automatic transmission.

A method of controlling an automatic transmission mounted on a vehicle having an automatic engine stop mechanism for automatically stopping and restarting an engine, is provided. The transmission includes a piston having first and second surfaces, friction plates, engaging and disengaging hydraulic pressure chambers, a hydraulic pressure control valve for supplying/discharging hydraulic pressure to/from the chambers, first and second oil paths communicating the control valve with the chambers, a pressure reducing valve for preventing pressure of the disengaging chamber from exceeding a given set pressure, a hydraulic pressure supply device for supplying pressure to the control valve in the automatic stop state, and a mechanical oil pump for supplying pressure to the control valve while the engine is driving, the second surface having a larger pressure receiving area than the first surface. The method includes adjusting the set pressure to be lower in the automatic stop state than while driving.