Nsk Corporation

Makoto Fujinami

Nobuo Goto

Hiroshi Kato

Hiroyuki Itoh

Takashi Imanishi

Hisashi Machida

Nobuaki Mitamura

Seiji Higuchi

Kiyoshi Okubo

Hiroshi Fukushima

Hiroyuki Ito

Kouji Ishikawa

Hiroshi Iwasa

Satoshi Kadokawa

Moichi Chiba

Masayoshi Shimizuya

Noriyuki Takeo

Takeyuki Yoshiba

Katsuhiro Ikezawa

Makoto Hinohara

Syuuichi Tsubouchi

Koji Ishikawa

Even when used at a high rotation speed, outside parts in relation to the radial direction of a cage, of the circumferential parts of a pocketare kept from being worn away by outside end surfacesof rollers. Moreover the rollersare kept from sliding on the inside the pockets, to thereby stabilize the performance of rotation support parts. The outside end surfaceof the rolleris made a ball convex surface, so that the center part of the outside end surfacecan be freely in contact with the inner peripheral surface of a second outside cylindrical portion. In a condition with the rollersdisplaced radially outward of the cagedue to centrifugal force, a PV value of a rubbing part between the outside end surfaceand the opposite surface is kept low, and the wear of this rubbing part is suppressed.

Thrust roller bearing

It is an object of the invention to provide a needle bearing which can prevent occurrence of flake and seizure in the bearing parts even under such severe lubricating condition as provided by a compressor for a car air conditioner or a planetary unit for an automatic transmission. The needle bearing is structured by barrel grinding the raceway surface of a ring and the surface of a rolling body without using a ceramic-related abrasive such as alumina or silicon carbide.

Needle bearing and method for grinding bearing parts thereof

A loading cam apparatus for a toroidal type continuously variable transmission includes: a first cam surface formed to have concave and convex portions thereon along a circumferential direction thereo, a second cam surface formed to have concave and convex portions thereon along a circumferential direction thereof and to oppose to the first cam surface along an axial direction thereof, a plurality of rolling elements sandwiched between the first cam surface and the second cam surface, and a retainer for holding the plurality of rolling elements in a freely rotatable state. The retainer includes a retainer main body of a circular annular shape, and pockets provided at outer periphery portions of the retainer main body for holding the plurality of rolling elements, respectively. The retainer main body is formed by carbonitriding material of iron system with a carbon concentration in a range from 0.02 to 0.20 wt % both inclusive.

Loading cam apparatus for toroidal type continuously variable transmission

A toroidal type continuously variable transmission, includes: at least one pair of disks concentrically disposed on each other and rotatably supported independent from each other; a trunnion swingable about a pivot shaft; a displacement shaft including a support shaft portion and a pivot shaft portion that are parallel and eccentric to each other, the support shaft portion rotatably supported to the circular hole of the trunnion through a radial bearing, the pivot shaft portion being protruded from an inner surface of the middle portion of the trunnion; a power roller nipped between the concave surfaces of the pair of disks while being rotatably supported on an outer circumferential surface of the pivot shaft portion; and a thrust bearings located between the power roller and the inner surface of the middle portion of the trunnions. An eccentric quantity of the displacement shaft being a distance between the support shaft portion and the pivot shaft portion is within a range from 5 mm to 15 mm.

Toroidal type continuously variable transmission

In order to facilitate an assembling operation of a structure which is correctly operated with a proper positional relation, in a power roller unit for a toroidal type continuously variable transmission according to the present invention, a displacement shaft, a power roller, a radial needle bearing, a thrust ball bearing and a thrust needle bearing are pre-assembled to a trunnion. After dimensional relations and operation conditions of the constructural parts of the assembly or unit are ascertained, the assembly is assembled within a housing together with other unit, thereby completing the toroidal type continuously variable transmission.

Power roller unit and output disc unit for toroidal type continuously variable transmission

In the toroidal-type continuously variable transmission, the torque transmission shaft includes a flange portion formed in one end thereof, while a securing portion is formed in the end-face side half section of the flange portion so as to be able to secure a tool thereto when tightly fastening a loading nut to a external thread portion formed in the torque transmission shaft . And, the outer peripheral surface of the securing portion is formed as a polygonally cylindrical shape having four or more flat surfaces. Also, after the torque transmission shaft is heat-carburized and the surface of a cylindrical portion formed in the torque transmission shaft is removed, the external thread portion is worked, which makes it possible not only to secure the hardness of the adjoining portions of the external thread portion but also to control the hardness of the external thread portion itself. Further, branch oil supply passages and used to supply oil to ball splines and are formed at the positions of the torque transmission shaft that are shifted in the axial direction of the torque transmission shaft from the positions of balls , which respectively construct the ball splines and

Toroidal-type continuously variable transmission

A toroidal type continuously variable transmission, includes: at least one pair of disks concentrically disposed on each other and rotatably supported independent from each other; a trunnion swingable about a pivot shaft; a displacement shaft including a support shaft portion and a pivot shaft portion that are parallel and eccentric to each other, the support shaft portion rotatably supported to the circular hole of the trunnion through a radial bearing, the pivot shaft portion being protruded from an inner surface of the middle portion of said trunnion; a power roller nipped between the concave surfaces of the pair of disks while being rotatably supported on an outer circumferential surface of the pivot shaft portion; and a thrust bearings located between the power roller and the inner surface of the middle portion of the trunnions. An eccentric quantity of the displacement shaft being a distance between the support shaft portion and the pivot shaft portion is within a range from 5 mm to 15 mm.

In the toroidal-type continuously variable transmission, the radial needle roller bearing includes a plurality of needle rollers, the two end portions of each of the needle rollers in the axial direction thereof are crowned, and the crowning amount is set such that, in the portion of the needle roller that is situated by 7-13% of the axial-direction length toward the axial-direction central portion of the needle roller from the axial-direction end face of the needle roller, the crowning amount is 0.1-0.4% of the outside diameter of the axial-direction central portion of the needle roller. Further, in the inner peripheral surface of the output-side disk, there are formed a fitting portion to be fitted outside with a member rotatable in conjunction with the output-side disk and an outer race raceway portion for the needle roller bearing, in the portion of the inner peripheral surface of the output-side disk that is situated near to the inside surface thereof, there is formed a residual compressive stress layer by shot peening, and the outer race raceway portion is ground so as to remove a portion of the residual compressive stress layer, to thereby form the outer race raceway portion as a smooth surface.

In order to facilitate an assembling operation of a structure which is correctly operated with a proper positional relation, in a power roller unit for a toroidal type continuously variable transmission according to the present invention, a displacement shaft, a power roller, a radial needle bearing, a thrust ball bearing and a thrust needle bearing are pre-assembled to a trunnion. After dimensional relations and operation conditions of the constructural parts of the assembly or unit are ascertained, the assembly is assembled within a housing together with other unit, thereby completing the toroidal type continuously variable transmission. That is to say, according to the present invention, since the dimensional relations and operation conditions of the constructural parts can be ascertained in a condition such parts can easily be disassembled and re-assembled, a structure in which the positional relation between the constructural parts is maintained with high accuracy can be manufactured cheaply without any troublesome operations.

Power roller unit and output disc unit for torodial type continuously variable transmission

A continuously variable transmission provided with a rotary shaft characterized in that a ball spline is formed between an inner peripheral surface of a first disc and an outer peripheral surface of an intermediate portion of a rotary shaft, a restraining members for limiting displacement of balls of a ball spline is provided on an inner side of the inner peripheral surface of the first disc, a small-diametered portion is formed on the outer peripheral surface of the intermediate portion of the rotary shaft and between the first disc and a second disc, and the restraining members is mountable through the small-diametered portion with the restraining members and the small-diametered portion axially aligned with each other.

Continuously variable transmission

An angular bearing of a dual cavity toroidal type continuously variable transmission, includes: a torque input shaft having a shaft-side raceway groove formed in an outer peripheral surface of a flange portion provided in an end thereof; a loading cam unit of a loading cam unit having a disc-side raceway groove formed in an inner peripheral surface of a jointing opening thereof, the loading cam unit located around the end of the torque input shaft; and a plurality of balls held between the shaft-side raceway groove and the disc-side raceway groove to bear thrust loads exerted on the cam disc, wherein each of an angular contact angle between the balls and the shaft-side raceway groove and an angular contact angle between the balls and the disc-side raceway groove is 60&deg; or smaller, and each of a curvature radius of a groove surface of the shaft-side raceway groove and that of a groove surface of the disc-side raceway groove is from 52% to 55% of a diameter of the ball.

Angular bearing of dual cavity toroidal type continuously variable transmission

A cam disk for use in a loading cam mechanism of a toroidal type continuously variable transmission comprises a first projecting portion, a second projecting portion, a flange portion, a cam surface, a bearing raceway and a corner section. The cam disk has metal flows along the cam surface, metal flows along a surface of the raceway, and metal flows along a surface of the corner section. To produce the cam disk, material is shaped into a predetermined form through a first forging step using a first die unit, a second forging step using a second die unit, a third forging step using a third die unit, a finishing step, etc. The metal flows are also formed in these steps.

Cam disk for toroidal type continuously variable transmission

An outer race of a thrust ball bearing supporting a thrust load applied to a power roller is rotatably supported around a displacement shaft. A portion in which the contact pressure between an outer race track and the rolling surface of a rolling member is high changes so that the fatigue of the outer race track does not progress locally. Also, the power roller and the outer race are subjected to predetermined treatment and working. Irrespective of a great thrust load applied during operation, stress is alleviated and the lubricating property of the portion of contact is made good to thereby prevent cracks or early wear from occurring.

Improved input and output discs for toroidal type continuously variable transmissions are obtained by select processing techniques to form hardened layers. Processing techniques include, e.g., carburizing, carbonitriding, and high-frequency induction hardening. Shot peening may be used to impart compressive residual surface stress to predetermined disc portions to enhance resistance to cracking.

The ball spline for use in a troidal-type continuously variable transmission comprises a plurality of spline grooves and a plurality of balls which are arranged in series within spline gaps each constituted by a set of mutually opposing spline grooves, in which, while allowing the movement of the input disc in the direction of an input shaft by means of contact between the spline gaps and balls, the input shaft and input disc can be drivingly connected to each other. In the ball spline, the number of spline gaps is set different from integral multiples of the number of power rollers which are held by and between the input and output discs in contact with the two discs in order to transmit a rotation torque between the input and output discs. Further, each of the spline grooves includes inner and outer peripheral surface side spline grooves, and the shape of each of the sections of the two inner and outer peripheral surface side spline grooves respectively forming the ball spline is formed as a Gothic arch shape. And, the radius of curvature of the section of the groove bottom portion arc surface forming the groove bottom portion of each of the spline grooves is set more than or equal to 15% of the diameter of the ball. Also, the outer peripheral surface side chamfers of the outer peripheral surface side spline groove are set smaller to thereby be able to secure the effective grinding surface of the outer peripheral surface side spline groove.

Growing community of inventors

Kanagawa, Japan

Makoto Fujinami