Nissan Motor Company Limited

Jatco Corporation

Jun Sugihara

Toshikazu Oshidari

Haruhito Mori

Hiromasa Sakai

Toshifumi Hibi

Masatoshi Fukuyama

Masaki Nakano

Jun Watanabe

Haruyoshi Kumura

Motoharu Nishio

Daiki Tanaka

Tsuyoshi Sakuma

Tsutomu Yamazaki

Osamu Shimoyama

A four-wheel drive system for a hybrid vehicle includes at least two motor-generators and a single engine connected to a differential having multiple degrees of freedom. In some embodiments, by adjusting the outputs of the motor-generators, a controller allocates power from the engine, to or from each of the motor-generators, to the front wheels and to the rear wheels, each of which is connected to an element of the differential. The relationship between the elements of the differential is represented by an alignment chart of the differential.

Hybrid four-wheel-drive

A speed change device has an input member rotatable in opposite directions to transmit higher torque as its rotation angle becomes larger, and a variable angle-ratio change mechanism including rollers and teethed wheels that are arranged in parallel to each other. The rollers and teethed wheels are respectively connected to rotate together with each other. The teeth of the wheels have a clearance on a pitch circle between their adjacent teeth so that the clearance is larger than a slip amount of the rollers in a low torque range where the rollers transmit low torque with bypassing the wheels in a normal operation. The wheels are engaged with each other to transmit high torque in a high torque range where the high torque is applied in an exceptional operation and the rollers slip larger than the slip amount in the low torque range.

Speed change device and steering system

When, with engine kept stopped, driven road wheels are turned, the toroidal type continuously variable transmission is suppressed from shifting toward a higher speed side. That is, when, with the engine kept stopped, the road wheels are turned in a reverse direction due to a traction of a motor vehicle with its front end facing backward, an extra oil pump driven by the road wheels produces an oil pressure which is applied to a hydraulic servo mechanism to keep a speed change ratio at a lower speed side. While, when, with the engine kept stopped, the road wheels are turned in a forward direction due to a traction of the motor vehicle with its front end facing forward, the oil pressure produced by the extra oil pump is not practically used. Under this condition, a biasing spring suppresses a servo piston from moving in a direction to bring about a speed change ratio for the higher speed side.

Toroidal type continuously variable transmission

In a toroidal continuously variable transmission, a primary oil pump is driven by an engine, whereas a secondary oil pump is driven in response to rotation of a road wheel. A hydraulic servo mechanism is connected to a trunnion to create an offset of the trunnion from a neutral position for a tilting motion of the power roller. Also provided is a hydraulic system that supplies the hydraulic pressure discharged from the secondary pump to the hydraulic servo mechanism to prevent the offset of the trunnion in the trunnion-axis direction, corresponding to an upshift, occurring owing to rotation of the road wheel in a stopped state of the engine. A modulated hydraulic pressure, which is constantly produced by the hydraulic system during operation of the engine, acts to hold the secondary pump at either of an inoperative state and an unloaded condition during the operation of the engine.

Toroidal continuously variable transmission

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.

A toroidal continuously variable transmission including input and output disks rotatable about a common first axis, and power rollers interposed therebetween and supported on trunnions to rotate about a second axis. The trunnions are displaceable along a third axis extending perpendicular to the second axis and pivotally moveable about the third axis. A link connects the trunnions. A link support supports the link to allow the displacement and pivotal movement of the trunnions. A pin extending parallel to the first axis and a pin guide having an open end cooperate to support the link so as to swing about the pin and offset along the third axis. The pin is disposed on one of the link and the link support, and the pin guide is disposed on the other. Upon mounting the link to the link support, the pin is radially inserted into the pin guide through the open end.

A ratio control for a toroidal-type traction drive comprises toroidal discs defining a toroidal cavity. Traction roller assemblies have pivot trunnions rotatably supporting traction rollers. A ratio control element is provided, which is positionable to establish various ratios between the toroidal discs. A feedback structure is connected to the ratio control element and includes a ratio control valve to hydraulically control the traction roller assemblies, and a cam follower. A feedback cam is provided, which cooperates with the cam follower. A lost motion cam actuator is provided between a predetermined pivot trunnion and the feedback cam to permit limited independent deflected movement of the predetermined pivot trunnion from the pivot axis thereof without requiring corresponding movement of the feedback cam.

Ratio control for toroidal-type traction drive incorporating lost motion cam actuator

A speed change control system is equipped with a feedback mechanism which feeds back the gyration angle of a power roller and the axial displacement of the power roller, to a speed change control valve ( ) via a speed change link ( ). The feedback mechanism comprises a cam plate ( ) which outputs a feedback amount according to the gyration angle of the power roller, an L-shaped link ( ) which outputs a feedback amount according to the axial displacement of the power roller, and a feedback link ( ) connected to the cam plate ( ) and L-shaped link ( ), and connected to the speed change link ( ). The feedback gain of the feedback amount according to the axial displacement of the power roller due to the L-shaped link ( ), is varied according to the gyration angle of the power roller.

Speed change control system of toroidal continuously variable transmission

A speed change control valve ( ) houses a spool ( ) of comprising a land ( ) which can face a supply port ( P) supplying an oil pressure, and lands ( ) which can respectively face a pair of drain ports ( D, D) formed on either side of the supply port ( P). Output ports ( L, H) which allow a first and second oil chamber of an hydraulic cylinder to communicate selectively with the supply port ( P) or the drain ports ( D) according to the displacement of a spool ( ), are provided in the speed change control valve ( ). In the neutral position of the spool ( ), the lands ( ) respectively face the drain ports ( D), a width L of the land ( ) is set to be equal to or greater than a width L of the supply port ( P), and a width L of the lands ( ) is set to a width at which the drain port ( D) can open.

Speed change control device for a continuously variable transmission

A lubricating system for a toroidal continuously variable transmission equipped with a trunnion rotatably supporting a power roller gripped between input and output disks so that a gyration angle of the power roller is variable, includes a first lubricating circuit provided for lubrication of a rolling contact surface on which the input and output disks are in friction-contact with the power roller, and a second lubricating circuit provided for lubrication of the trunnion and the power roller. Also provided in the first lubricating circuit is an oil-temperature control device that heats oil of the toroidal continuously variable transmission, so that the oil temperature-controlled by the oil-temperature control device is supplied through the first lubricating circuit into the rolling contact surface.

Lubricating system for toroidal continuously variable transmission

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.

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 friction roller type continuously variable transmission comprises input and output discs arranged on a common axis; friction rollers each being operatively interposed between the input and output discs to transmit torque therebetween; supporting members each rotatably supporting the friction roller and having a shaft extending therefrom; servo-pistons each including a hollow boss portion which has the shaft of the corresponding supporting member slidably received therein, the hollow boss portion being capable of pushing the corresponding supporting member to pivot the corresponding friction roller to continuously change a speed ratio between the input and output discs; and links each connecting corresponding ends of the supporting members to suppress displacement of each friction roller which would occur when the friction roller is applied with a certain thrust from the input and output discs. Articulated structures are provided each being arranged between the hollow boss portion and the corresponding supporting member to permit a pivotal movement of the supporting member relative to the hollow boss portion. Positioning structures are further provided each effecting a relative rotational positioning between the supporting member and the corresponding hollow boss portion.

Friction roller type continuously variable transmission

A toroidal continuously variable transmission (11) having power rollers (18A-18D) held between input discs (19, 20) and output discs (21, 22) and transmitting power and a torque converter (12) having a lock up clutch (12D) connected to the continuously variable transmission (11) are provided. The line pressure of a working fluid supplied from a pump (1) is adjusted by a pressure regulator valve (2), and the adjusted line pressure is introduced to a lock up control valve (5) for controlling a fluid pressure to be supplied to the lock up clutch (12D) of the torque converter (12) through a pressure passage (31). Further, an oil cooler (32) is interposed in a downstream portion of the lock up control valve (5). The lubricating circuit of the continuously variable transmission is separated into a first lubricating circuit 33 for lubricating a bearing member of the power rollers (18A-18D) and a second lubricating circuit (35) for lubricating a rolling surface between the input and output discs (19-22) and the power rollers (18A-18D). The first lubricating circuit (33) is connected to a downstream portion of the cooler (32) and the second lubricating circuit (35) is connected to an upstream portion of the lock up control valve (5).

Hydraulic pressure control device of automatic transmission

Lateral wear of a contact position of a cam face of a precess cam which displaces in response to the gyrational state of a power roller and a cam follower which is provided on a feedback link is reduced. The cam follower (55) which contacts with the cam face (54) of the precess cam (52) is mounted on the feedback link (53) and the cam follower (55) comprises a three-dimensional curve such a rotating barrel-shaped body. Even if the cam face (54) of the precess cam (52) inclines, the cam follower (55) is normally maintained in a stable contact state. In this way, wear is reduced and durability is increased.

Growing community of inventors

Kanagawa, Japan

Jun Sugihara