Nissan Motor Company Limited

Jatco Corporation

Haruhito Mori

Masaki Nakano

Jun Sugihara

Toshifumi Hibi

Jun Watanabe

Toshikazu Oshidari

Haruyoshi Kumura

Yuusuke Minagawa

Masatoshi Fukuyama

Eio Sagara

Ryuichi Murase

Kunihiko Morikawa

Tsutomu Yamazaki

Takeo Yoshida

Masayuki Nagai

Keiichi Kawashima

In a toroidal continuously variable transmission, a roller-and-cage bearing assembly is interleaved between a power-roller outer ring and a trunnion power-roller accommodating portion to permit a parallel translation of a power roller in an axial direction of input and output disks. A cage of the roller-and-cage bearing assembly is formed with an oval slotted hole. A disk-shaped member is attached to the trunnion power-roller accommodating portion. The slotted hole and the disk-shaped member are fitted to each other to define a predetermined clearance that limits a displacement of the roller-and-cage bearing assembly in a direction perpendicular to both a rotation axis of the power roller and a trunnion axis to a set displacement.

Toroidal continuously variable transmission

A toroidal continuously variable transmission includes an input disk, an output disk facing the input disk, a power roller gripped between the input disk and output disk, a pedestal which supports the power roller free to rotate about a power roller rotation axis, and a trunnion which gyrates about a trunnion gyration axis. The trunnion includes a first plane portion perpendicular to the power roller rotation axis, two second plane portions perpendicular to the first plane portion and facing each other across the power roller rotation axis and two inclined portions between the first plane portion and the second plane portions, respectively. A roller bearing unit, including a cage housing a roller, supports the pedestal on the trunnion so that the pedestal is free to slide in a direction that is perpendicular to both the trunnion gyration axis and power roller rotation axis. Limiting members, that limit the slide amount of the cage of the power roller bearing relative to the trunnion, are provided on the inclined portions. In this way, the projections serve as a rib, which raises the rigidity of the trunnion. Therefore, deformation of the trunnion is reduced even if overload acts on the trunnion via power roller.

A wall mounting structure for a dual cavity toroidal continuously variable transmission (CVT) including two toroidal speed change units. Each toroidal speed change unit includes a pair of input and output disks rotatable about a common rotation axis, the input disks being axially spaced from each other, the output disks being disposed between the input disks and axially opposed to each other in a spaced relation, and a gear set drivingly connected with the output disks. The wall mounting structure includes a transmission case accommodating the toroidal speed change units, an intermediate wall disposed between the output disks and accommodating the gear set, and a fastener fixing the intermediate wall to the transmission case and extending in a direction perpendicular to the rotation axis of the output disks.

WALL MOUNTING STRUCTURE FOR DUAL CAVITY TOROIDAL CONTINUOUSLY VARIABLE TRANSMISSION AND METHOD OF ASSEMBLING THE DUAL CAVITY TOROIDAL CONTINUOUSLY VARIABLE TRANSMISSION WITH THE WALL MOUNTING STRUCTURE

A toroidal continuously-variable transmission includes a tilt rotation stopper structure to limit a range of rotation of a trunnion supporting a power roller in a toroidal cavity between input and output disks, so as to prevent contact points of the power roller with the input and output disks from deviating from respective rolling contact surfaces. The tilt rotation stopper structure includes a link-side stopper provided in a lower or upper link in a region separated from a left and right tilt rotation synchronizing wire, and a trunnion-side stopper provided in a side of an axial movement limiting member.

Toroidal continuously-variable transmission

In a toroidal type continuously variable transmission, a pair of power rollers are operatively interposed between input and output discs. Each power roller includes a power inner roller frictionally engaged with the input and output discs, a power outer roller receiving an axial load applied to the power inner roller from the input and output discs, a ball bearing operatively interposed between the power inner and outer rollers and a shaft receiving a radial load applied to the power inner roller from the input and output discs. The shaft is a one-body member comprising a first shaft portion on which the power outer roller is coaxially and tightly disposed and a second shaft portion on which the power inner roller is coaxially and rotatably disposed. The power outer roller and the shaft are produced separately. Upon assembly, these two parts are coupled together to constitute an integrated unit.

Toroidal type continuously variable transimission

Plural cooling passages extending radially are formed from the inner circumference to the outer circumference and within an output disk common to two toroidal transmission units. Lubricating oil which has reached an annular space between the output disk and the main shaft via holes from an oil passage in the main shaft, flows into the cooling passages inside the output disk, and the output disk is thereby cooled from inside.

Cooling and lubricating mechanism of toroidal continuously variable transmission

A toroidal continuously variable transmission ( ) comprises input disks ( ), output disks ( ) facing the input disks, power rollers ( ) gripped between the input disks and output disks, a pedestal ( ) which supports the power rollers free to rotate, trunnions ( ) and roller bearing units ( ) which support the pedestals on the trunnions so that they are free to slide in the direction perpendicular to the trunnion gyration axis ( ) and power roller rotation axis ( ), and further comprises projections ( ) which limit the slide amount of a cage ( ) of the roller bearing unit relative to the trunnions. In this way, even if the power roller repeatedly slides relative to the trunnion ( ) in the direction perpendicular to the trunnion gyration axis ( ) and power roller rotation axis ( ), the cage ( ) does not protrude from the trunnion ( ), support of the load acting on the power roller is not insufficient, and the cage ( ) is prevented from interfering with the input and output disks as it would do if it protruded.

A toroidal type continuously variable transmission includes trunnions ( ) formed with shoulder portions ( ) which oppose an upper link ( ) and a lower link ( ), and projections ( ) on the links ( ) which can slide on the shoulder portions ( ) when the links ( ) perform swinging movement. Along with forming the trunnions ( ) in single units by forging, step portions ( B) are arranged between the shoulder portions ( ) and sloping portions ( ) of the offset portions ( A). Planar portions ( A) are formed in the shoulder portions ( ) which can slide on the projections ( ) by cutting or grinding so that their radiuses R from the rotation axes ( C) up to the end portions of the step portions ( B) are set in advance.

Toroidal type continuously variable transmission and method for manufacturing trunnion

Power rollers are comprised by an inner roller making frictional contact between the input and output disks and an outer roller supporting a contact load input from the input and output disks to the inner roller through a ball bearing . An inner radial hole is provided on the inner roller to support a pivot shaft . The inner radial hole opens near the outer roller and is covered by a bottom part on a side opposite to the outer roller. In this manner, compression deformation of the inner roller is suppressed when a load is applied to the inner roller. Thus smooth rotational motion of the power roller is maintained and component durability can be increased.

A power roller ( ) comprises a power roller inner wheel ( ) in frictional contact with a input/output disks ( ), a power roller outer wheel ( ) provided in a trunnion ( ), a ball bearing ( ) interposed between the power roller inner wheel ( ) and the power roller outer wheel ( ), and an inner wheel supporting shaft ( ) which supports the power roller inner wheel ( ) such that it is free to rotate, the shaft having a shaft base part ( ) supported in the trunnion ( ), and arranged so that the radial support rigidity is set high in a gyration axis direction and set low in the direction perpendicular to the trunnion gyration axis ( ) and the power roller rotation axis ( ). When one of the disks is pressed and displaced in the direction of the other disk by the press member, the power roller inner wheel ( ) displaces with the ball bearing ( ) by the displacement of the one of the disks Therefore, as the radial support rigidity of the inner wheel supporting shaft ( ) is different depending on the support direction, a slide function of the power roller ( ) can be provided by a simple structure having a small number of component parts which does not have a slide mechanism.

In a toroidal type continuously variable transmission, shoulder portions are formed on a trunnion which opposes an upper link or a lower link, and projecting portions are formed on the links which slidably contact the shoulder portions when the links execute swinging movement. The end portions of the projecting portions which slidably contact the shoulder portions are formed with arcuate faces.

Toroidal type continuously variable transmission and method of manufacturing link

Even in the case where a driver switches a select lever from D range to N range and returns it back to D range during the running of a vehicle, a speed change control device prevents the operation of sudden speed change caused by a difference between a transmission input rotational speed and the actual input rotating speed of a toroidal transmission unit while in the N range. Accordingly, an automatic transmission comprises a forward-reverse switching mechanism, an impelling mechanism and a toroidal transmission unit which are sequentially arranged from the driving source side of a vehicle, and further comprises a speed change control device for controlling the operation of the above. A notch as a rotational speed signaling section is provided on the outer periphery of a loading cam, for example, among rotating members in the area from an output member of the above forward-reverse switching mechanism to an input disc of the above toroidal transmission unit, and the notch is detected by a rotation sensor arranged in the vicinity of the outer periphery to detect the rotational speed of the loading cam and input the same to the speed change control device.

Toroidal type automatic transmission for motor vehicles

A power roller (,C,,D,,C,,D) of a toroidal continuously variable transmission is supported by a pedestal (,) such that it is free to rotate. A first roller bearing (,A) supporting the pedestal (,) in the trunnion (,) against a horizontal load which makes a right angle with an input shaft (,) of the transmission, and a second roller bearing (,B,,C) supporting the pedestal (,) in the trunnion (,) against a vertical load which makes a right angle with the input shaft (,) of the transmission, are provided between the trunnion (,) and the pedestal (,). These roller bearings (,A), (,B), (,C) permit the pedestal (,) to easily displace parallel to the input shaft (,).

A shift control apparatus of a continuously variable transmission for a vehicle comprises sensors for detecting operating conditions of the transmission and a motor connected to the transmission. A controller of the shift control apparatus stores different shift maps and employs one of them according to a driver's command or vehicle driving condition. The controller decides a target value of an input rotation speed of the transmission from an output rotation speed of the transmission and the load condition of a motor on the basis of the shift map and continuously changes a gear ratio of the transmission so that the transmission input rotation speed is adjusted to the target value. The controller can change the rate of the shift speed indicative of a time period of a gear ratio changing operation according to a driver's command.

Shift control apparatus for continuously variable transmission

A lower section (,) of a piston boss (,) of a hydraulic cylinder (,) is formed with a small radius and is inserted into a fixed gap provided with respect to the inner peripheral face of the cylinder through hole (,). A thrust force F is applied to trunnions (,) supporting power rollers (,) and the trunnions (,) deform about a support position connected by an upper link (,) and a lower link (,). At the same time, even if the lower end (,) of the piston boss (,) undergoes a large inclination, no adverse effect results on the inner peripheral face of the cylinder through hole (,). Even if the sliding section of the piston undergoes a large inclination together with a deformation of the trunnions (,), local wear and damage to the sliding face on the cylinder inner periphery can be avoided.

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Yokohama, Japan

Haruhito Mori