A transmission device for a hybrid vehicle including: a plurality of shift dog clutches each arranged to selectively engage the movable side gear of one of the shift gear rows with the other of the main shaft and the counter shaft; a main clutch disposed between the internal combustion engine and the main shaft; a first motor gear disposed to be raced with respect to a motor output shaft connected to the motor, and constantly interlocked with the main shaft; a second motor gear disposed to be raced with respect to the motor output shaft, and constantly interlocked with the counter shaft; a motor dog clutch arranged to selectively engage one of the first and second motor gears with the motor output shaft; and a controller configured to control actuations of the shift dog clutch, the main clutch, and the motor dog clutch.

A hydraulic control system includes a hydraulic pump driven by an electric motor, a solenoid valve having an output that controls the positions of a pressure regulator valve and a third, stator shift valve. The solenoid valve is a normally high, variable force solenoid valve which provides a control signal to the second and third valves. The second, pressure regulator valve is a multiple port valve which controls hydraulic fluid flow both to a transmission oil cooler (ATOC) and to an exhaust port, thereby maintaining a desired system pressure. The third, stator shift valve is also a multiple port valve and it controls fluid flow to the stator of the electric pump motor to provide cooling and to a dog clutch of the transmission to disengage it.

At the time when a hydraulic actuator is operated to engage a dog clutch, after it is detected that a hydraulic pressure for operating the hydraulic actuator is higher than or equal to a predetermined hydraulic pressure, it is determined whether the dog clutch is not engaged. Therefore, non-engagement determination due to insufficient hydraulic pressure for operating the hydraulic actuator is prevented. Thus, at the time when the hydraulic actuator is operated to engage the dog clutch, it is possible to prevent consumption of time to engage the dog clutch due to unnecessary re-engagement operation.

A first engagement member includes a first meshing portion and rotates integrally with a first shaft. A second engagement member includes a second meshing portion configured to mesh with the first meshing portion and rotates integrally with a second shaft. An electric clutch device drives the first engagement member via a pressing member that extends and contracts in response to drive of a clutch actuator. When the electric clutch device is to be engaged, the first shaft command computation unit sets the first shaft rotation speed command value to be smaller than the rotation speed of the second shaft. Further, after the rotation speed of the first shaft matches the first shaft rotation speed command value, the first shaft command computation unit sets the first shaft rotation speed command value to be gradually closer to the rotation speed of the second shaft.

An automatic transmission system includes a housing containing automatic transmission fluid (ATF), a plurality of clutches configured to be engaged to generate gear ratios corresponding to forward speeds of the automatic transmission, wherein one clutch of the plurality of clutches is a friction clutch movable between a disengaged state, an engaged state utilized to create one or more gear ratios of the automatic transmission, and a slippingly engaged state between the disengaged state and the engaged state where the friction clutch is not engaged to create a gear ratio of the automatic transmission, and a controller configured to selectively move the friction clutch to the slippingly engaged state when the friction clutch is not being utilized to generate the one or more gear ratios, such that the friction clutch generates heat from friction to thereby rapidly heat the ATF in the housing and improve operating efficiency of the transmission.

Provided is a control device for a four-wheel drive which can maintain driving stability while restraining noise and vibration. A control device includes: a second control device that, when at least one of front wheel has slipped, engages a dog clutch after rotating a propeller shaft by a rotational force transmitted via first and second friction clutches; and a third control device that, if a predetermined condition is satisfied when the front wheels are not slipping, engages the dog clutch after rotating the propeller shaft by the rotational force transmitted via the first and second friction clutches. The time required to synchronize the dog clutch by the third control device is longer than that required to synchronize the dog clutch by the second control device.

An engagement device includes: an engaged body configured to rotate in conjunction with a rotary shaft; an engaging body arranged coaxially with the engaged body and configured to engage with the engaged body by movement in an axial direction; a power source configured to provide thrust to the engaging body in the axial direction; and a hub member configured to couple the engaging body to a torque receiver which receives torque transmitted from the engaged body at a time the engaging body engages with the engaged body. The engaged body, the engaging body, and the power source are accommodated in a closed space, and the hub member is at least a part of an outer shell forming the closed space.

A control device includes: an engagement mechanism having a first engagement element and a second engagement element; and an actuator that generates a thrust that brings the first engagement element and the second engagement element close to each other when the engagement mechanism is engaged. The control device performs engagement with the thrust of the actuator when a differential rotation speed of the engagement mechanism is less than a predetermined value. In the control device, a parameter indicating an operating state of the actuator is detected, a target differential rotation speed is calculated in accordance with a value of the detected parameter, and the differential rotation speed is controlled to the calculated target differential rotation speed.

A dog clutch engagement method of an electric four-wheel drive vehicle includes steps of: when dog clutch engagement is requested during driving, determining a target synchronization speed of the input gear to be a sum of an estimated speed and an offset speed of the output gear; operating a drive unit so that an input gear follows the target synchronization speed; when an actual speed of the input gear reaches the target synchronization speed, moving a sleeve to a meeting position at which the sleeve is in contact with the input gear; and when the actual speed of the input gear is synchronized with an actual speed of the output gear, transporting the sleeve to an engagement position at which the input gear and the output gear are coupled.

A transmission for a vehicle includes a first rotating member for rotation about an axis and a second rotating member for rotation about the axis. The first rotating member and the second rotating member are connectable to each other such that the first rotating member and the second rotating member are rotationally locked relative to each other for transferring torque between the first rotating member and the second rotating member. The transmission comprises a sensor arrangement for measuring a relative angular position of the first rotating member and the second rotating member while at least one of the first rotating member and the second rotating member is rotating.