Abstract: A downsized power transmission unit having engagement devices. A first engagement device comprises a cylindrical first sleeve, and a second engagement device comprises a cylindrical second sleeve to which the first sleeve is inserted at least partially. First spline teeth and first dog teeth are formed on an inner circumferential surface of the first sleeve. Second spline teeth are formed on any one of an inner circumferential surface and an outer circumferential surface of the second sleeve, and second dog teeth are formed on the other one of the inner circumferential surface and the outer circumferential surface of the second sleeve.

Abstract: A shift mechanism switches power transmission paths among a first transmission shaft, a second transmission shaft, and a third transmission shaft that are concentrically arranged on a rotational axis. The shift mechanism has a drive drum that is provided so as to be coaxial with the rotational axis and pivotable about the rotational axis, and a first driven drum and a second driven drum that are arranged on the rotational axis so as to be concentric with the drive drum and move along the rotational axis as the drive drum pivots. As the first driven drum moves, a first shift sleeve advances and retreats, and the first transmission shaft and the second transmission shaft are connected and disconnected. In addition, as the second driven drum moves, a second shift sleeve advances and retreats, and the second transmission shaft and the third transmission shaft are connected and disconnected.

Abstract: A control system for a hybrid vehicle that shift an operating mode to an appropriate mode from a low mode or high mode. The hybrid vehicle comprises a power split mechanism connected to an engine and a first motor. When a required brake torque of a prime mover cannot be achieved during propulsion in an operating mode established by engaging one of clutches while stopping the engine, the control system excites a motoring of the engine by the first motor while maintaining engagement of the clutch engaged to establish the current operating mode.

Abstract: A power transmission unit that can prevent unintentional disengagement of a clutch. A first set of teeth formed on an outer circumferential surface of a first rotary member is engaged with a third set of teeth formed on an inner circumferential surface of a second rotary member. A second set of teeth formed on an inner circumferential surface of the first rotary member is meshed with a fourth set of teeth formed on an outer circumferential surface of a third rotary member. A center of engagement between the first set of teeth and the third set of teeth is situated at a point withdrawn from a center of engagement between the second set of teeth and the fourth set of teeth in the direction to disengage the first set of teeth from the third set of teeth.

Abstract: A meshing engagement device includes a movable member; a first engaging element; a spring member; first engaging teeth formed on the first engaging element; and a second engaging element having second engaging teeth which engage with the first engaging teeth. Further, the meshing engagement device switches between an engagement state and a disengagement state, and the engagement state includes: a first engagement state where the spring member is brought into a state where the spring member is contracted in the axial direction; and a second engagement state where the spring member is brought into a state where the spring member is further contracted in the axial direction compared to the spring member in the first engagement state.

Abstract: A control system for a power transmission unit configured to shift an operating mode smoothly by manipulating engagement devices, and to simplify a structure of the power transmission unit. The control system is configured to reduce a speed difference between an axially stationary engagement element and a reciprocatable engagement element of a second engagement device when shifting from a first continuously variable mode to a second continuously variable mode by engaging the second engagement device. After the second engagement device has been engaged completely, a first engagement device is disengaged.

Abstract: A shift mechanism switches power transmission paths among a first transmission shaft, a second transmission shaft, and a third transmission shaft that are concentrically arranged on a rotational axis. The shift mechanism has a drive drum that is provided so as to be coaxial with the rotational axis and pivotable about the rotational axis, and a first driven drum and a second driven drum that are arranged on the rotational axis so as to be concentric with the drive drum and move along the rotational axis as the drive drum pivots. As the first driven drum moves, a first shift sleeve advances and retreats, and the first transmission shaft and the second transmission shaft are connected and disconnected. In addition, as the second driven drum moves, a second shift sleeve advances and retreats, and the second transmission shaft and the third transmission shaft are connected and disconnected.

Abstract: A power transmission unit that can prevent unintentional disengagement of a clutch. A first set of teeth formed on an outer circumferential surface of a first rotary member is engaged with a third set of teeth formed on an inner circumferential surface of a second rotary member. A second set of teeth formed on an inner circumferential surface of the first rotary member is meshed with a fourth set of teeth formed on an outer circumferential surface of a third rotary member. A center of engagement between the first set of teeth and the third set of teeth is situated at a point withdrawn from a center of engagement between the second set of teeth and the fourth set of teeth in the direction to disengage the first set of teeth from the third set of teeth.

Abstract: A control system for a power transmission unit configured to shift an operating mode smoothly by manipulating engagement devices, and to simplify a structure of the power transmission unit. The control system is configured to reduce a speed difference between an axially stationary engagement element and a reciprocatable engagement element of a second engagement device when shifting from a first continuously variable mode to a second continuously variable mode by engaging the second engagement device. After the second engagement device has been engaged completely, a first engagement device is disengaged.

Abstract: A control system for a vehicle that prevents an unintentional mode change when a command signal cannot be transmitted to an engagement device. In the vehicle, HV-Lo mode is established by connecting a carrier to a carrier by a first clutch while disconnecting the carrier from a ring gear by a second clutch, and HV-Lo mode is established by disconnecting the carrier from the carrier by the first clutch while connecting the carrier to the ring gear by the second clutch. A normally stay clutch is used as at least one of the first clutch and the second clutch.

Abstract: A shift mechanism switches power transmission paths among a first transmission shaft, a second transmission shaft, and a third transmission shaft that are concentrically arranged on a rotational axis. The shift mechanism has a drive drum that is provided so as to be coaxial with the rotational axis and pivotable about the rotational axis, and a first driven drum and a second driven drum that are arranged on the rotational axis so as to be concentric with the drive drum and move along the rotational axis as the drive drum pivots. As the first driven drum moves, a first shift sleeve advances and retreats, and the first transmission shaft and the second transmission shaft are connected and disconnected. In addition, as the second driven drum moves, a second shift sleeve advances and retreats, and the second transmission shaft and the third transmission shaft are connected and disconnected.

Abstract: A shifting mechanism whose axial length is reduced without increasing a manufacturing cost. The shifting mechanism comprises: a cylindrical cam; a serpentine cam groove formed on the cam; a cam follower contacted to the guide section to be reciprocated in an axial direction; and a shift fork connected to the cam follower. The cam follower is pushed onto one of walls of a cam groove serving as a guide wall by a pushing member.

Abstract: A meshing engagement device includes a movable member; a first engaging element; a spring member; first engaging teeth formed on the first engaging element; and a second engaging element having second engaging teeth which engage with the first engaging teeth. Further, the meshing engagement device switches between an engagement state and a disengagement state, and the engagement state includes: a first engagement state where the spring member is brought into a state where the spring member is contracted in the axial direction; and a second engagement state where the spring member is brought into a state where the spring member is further contracted in the axial direction compared to the spring member in the first engagement state.

Abstract: A power transmission apparatus includes a first meshing engagement mechanism that selectively couples a first rotational section and a second rotational section; and a second meshing engagement mechanism that selectively couples a third rotational section and a fourth rotational section. The first meshing engagement mechanism includes a first movable member provided with third meshing teeth that mesh with first meshing teeth provided on one of the first and the second rotational sections. The second meshing engagement mechanism includes a second movable member provided with fourth meshing teeth that mesh with second meshing teeth provided on one of the third and the fourth rotational sections. At least a portion of a first movable region of the third meshing teeth and at least a portion of a second movable region of the fourth meshing teeth overlap with each other in a radial direction with respect to a rotational axis.

Abstract: A first valve is disposed in an oil passage through which the engaging pressure generated by a linear solenoid valve is supplied to A second brake. The first valve is closed when the second brake is released, so as to close the oil passage, and is opened when the second brake is engaged, so as to open the oil passage. A second valve is disposed in a lubricating oil passage through which lubricating oil is supplied to the second brake, and communicates with the linear solenoid valve. The second valve is opened when the engaging pressure is supplied from the linear solenoid valve, so as to open the lubricating oil passage, and is closed when no engaging pressure is generated by the linear solenoid valve.

Abstract: A shift mechanism switches power transmission paths among a first transmission shaft, a second transmission shaft, and a third transmission shaft that are concentrically arranged on a rotational axis. The shift mechanism has a drive drum that is provided so as to be coaxial with the rotational axis and pivotable about the rotational axis, and a first driven drum and a second driven drum that are arranged on the rotational axis so as to be concentric with the drive drum and move along the rotational axis as the drive drum pivots. As the first driven drum moves, a first shift sleeve advances and retreats, and the first transmission shaft and the second transmission shaft are connected and disconnected. In addition, as the second driven drum moves, a second shift sleeve advances and retreats, and the second transmission shaft and the third transmission shaft are connected and disconnected.

Abstract: A control system for a hybrid vehicle that shift an operating mode to an appropriate mode from a low mode or high mode. The hybrid vehicle comprises a power split mechanism connected to an engine and a first motor. When a required brake torque of a prime mover cannot be achieved during propulsion in an operating mode established by engaging one of clutches while stopping the engine, the control system excites a motoring of the engine by the first motor while maintaining engagement of the clutch engaged to establish the current operating mode.

Abstract: A torsional vibration damper that can be arranged in a fluid coupling to downsize a powertrain is provided. The torsional vibration damper has a mass body held in a rotary member in such a manner to be oscillated by torque pulse of the rotary member. The rotary member is arranged in an internal space of a fluid coupling in which a pump impeller, a turbine runner and a predetermined stationary member are held in a casing. A planetary unit that performs a differential action among three rotary elements is arranged in the casing. In the planetary unit, a first rotary element is connected to the stationary member, a second rotary element is connected to the rotary member, and a third rotary element is connected to the turbine runner.

Abstract: A power transmission apparatus includes a first meshing engagement mechanism that selectively couples a first rotational section and a second rotational section; and a second meshing engagement mechanism that selectively couples a third rotational section and a fourth rotational section. The first meshing engagement mechanism includes a first movable member provided with third meshing teeth that mesh with first meshing teeth provided on one of the first and the second rotational sections. The second meshing engagement mechanism includes a second movable member provided with fourth meshing teeth that mesh with second meshing teeth provided on one of the third and the fourth rotational sections. At least a portion of a first movable region of the third meshing teeth and at least a portion of a second movable region of the fourth meshing teeth overlap with each other in a radial direction with respect to a rotational axis.

Abstract: A control system for a vehicle that prevents an unintentional mode change when a command signal cannot be transmitted to an engagement device. In the vehicle, HV-Lo mode is established by connecting a carrier to a carrier by a first clutch while disconnecting the carrier from a ring gear by a second clutch, and HV-Lo mode is established by disconnecting the carrier from the carrier by the first clutch while connecting the carrier to the ring gear by the second clutch. A normally stay clutch is used as at least one of the first clutch and the second clutch.