Toyota Jidosha Kabushiki Kaisha

Kabushiki Kaisha Toyota Chuo Kenkyusho

Isamu Shiotsu

Hirotsugu Yoshino

Akihiko Ichikawa

Takaho Kawakami

Motoki Tabuchi

Hideaki Komada

Seiji Kuwahara

Yosuke Suzuki

Fusahiro Tsukano

Shinichi Takeuchi

Jun Yabuta

Tomohiro Yoshimura

Yuuki Masui

Atsushi Honda

Takeshi Kamiya

Yasumitsu Osada

Yukihiro Inaba

Tomoyasu Kurimoto

Junichi Muraoka

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.

Shift mechanism for power transmission device

A dog clutch for a vehicle includes gear-side meshing teeth provided on a shifting gear fitted so as to be rotatable relative to a shaft, and a dog ring disposed adjacent to the shifting gear in the axial direction of the shaft. The dog ring includes a first ring, a second ring, and springs interposed between the two rings. The first ring is provided with meshing teeth that can be meshed with the gear-side meshing teeth of the shifting gear. The second ring is provided with meshing teeth that can be meshed with the gear-side meshing teeth of the shifting gear. The springs are provided on the inner peripheral side of a circle that is centered on a rotational axis and that circumscribes a portion of the meshing teeth of the first ring and the second ring positioned on the outermost peripheral side.

Dog clutch for vehicle

A dog clutch includes a gear () mounted on a power transmission shaft (), first and second dog rings (), a fork (), springs (), and cam grooves (). The cam grooves () each include a first slope surface () inclined from the axial direction toward the positive rotation direction as the first slope surface () approaches the gear () and a second parallel surface () parallel to the axial direction. The first dog ring () includes first cam protrusions () to be engaged with the respective first slope surfaces (), and the second dog ring () includes second cam protrusions () to be engaged with the respective second parallel surfaces (). This structure prevents the dog rings and the fork from coming into contact with each other, thereby avoiding generation of abrasion and increasing the transmission efficiency.

Dog clutch and transmission

A dog clutch includes a rotating member including first dog teeth, an annular dog ring including second dog teeth, and an annular dog sleeve. The rotating member includes first protrusions protruding radially outwardly from the outer circumferences of crests or troughs of the first dog teeth, the dog sleeve includes second protrusions that are configured to come into contact with the first protrusions in a circumferential direction when the dog sleeve moves toward the rotating member in an axial direction, and the first dog teeth and the second dog teeth are disposed at positions at which the first dog teeth and the second dog teeth are able to be engaged with each other in the circumferential direction in a state in which the first protrusions and the second protrusions are in contact with each other.

Dog clutch

A meshing-type engagement device includes a first member, a second member, a pressing mechanism, and a reaction force mechanism. The first member is provided with a plurality of first dog teeth. The second member is provided with a plurality of second dog teeth. The pressing mechanism is configured to press the first member to the second member side. The reaction force mechanism is configured to generate a reaction force with respect to a pressing force pressing the first member for the first dog teeth and the second dog teeth to mesh with each other such that the amount of increase in the reaction force with respect to a movement of the first member is larger at a position further on the second member side than a predetermined position compared to the amount of increase to the predetermined position when the first member is pressed.

Meshing-type engagement device

A translational force Fh to one side in a rotational axis direction is caused to act from a hydraulic piston to a sleeve when an engaged stage between an engagement tooth and an engaged tooth is maintained, so that translation of the sleeve to the other side in the rotational axis direction and consequent disengagement of the engagement tooth and the engaged tooth can be prevented. Therefore, the engaged state between the engagement member and the engaged member can be stably maintained regardless of the condition of the torque acting from the drive source to the engagement member.

Engagement device and automatic transmission

A control system for a meshing type engagement mechanism includes a meshing type engagement mechanism and an electronic control unit. The electronic control unit is configured to allow a fluid chamber to be filled with a fluid by putting a switching valve into a cut-off state after respective dog teeth mesh with each other by a second member reaching a predetermined position determined in advance in response to a fluid pressure of the fluid chamber such that the second member is pressed in the direction in which the second member is separated from a first member by a release force depending on the torque transmitted between a surface of a first tooth and a surface of a second tooth, the fluid pressure of the fluid chamber is increased, and an engagement state between the first member and the second member is maintained by the fluid pressure which is increased.

Control system for meshing type engagement mechanism

Under the condition that the rotation speed of a first rotating shaft is higher than that of a second rotating shaft, supported portions go through right-handed helical flutes to perform an engaging operation. Under the condition that the rotation speed of the first rotating shaft is lower than that of the second rotating shaft, the supported portions go through left-handed helical flutes to perform the engaging operation. In a releasing operation, the supported portions go through the right-handed helical flutes to release a clutch mechanism under the condition that the rotation speed of the first rotating shaft is lower than that of the second rotating shaft, and the supported portions go through the left-handed helical flutes to release the clutch mechanism under the condition that the rotation speed of the first rotating shaft is higher than that of the second rotating shaft.

Growing community of inventors

Nagakute, Japan

Isamu Shiotsu