Nsk Corporation

Nobuo Goto

Takashi Imanishi

Hiroshi Kato

Makoto Fujinami

Hiroyuki Itoh

Hisashi Machida

Kouji Ishikawa

Nobuaki Mitamura

Seiji Higuchi

Masami Tanaka

Yasuo Murakami

Hiroki Nishii

Norihisa Kobayashi

Kiyoshi Okubo

Hirotoshi Aramaki

Hiroshi Fukushima

Tomofumi Yamashita

Masayoshi Shimizuya

Yutaka Sato

Hiroyuki Ito

Hiromichi Takemura

Yuji Nakano

Tomonobu Yoshikawa

Yuya Daikoku

Kinji Yukawa

Toshirou Toyoda

Shouji Yokoyama

Koji Ishikawa

Tutomu Abe

Construction of a toroidal continuously-variable transmission is achieved that simplifies the manufacture of parts, management of parts and assembly work, is able to easily reduce costs, stabilizes speed change operations, and is processed easily. An outer ringof a thrust rolling bearing is supported so as to be able to pivotally displace by engaging a concave sectionthat is provided on the outside surface of the outer ringwith a cylindrical convex surfaceof a support beamof a trunnion. Displacement of the outer ringin the axial direction of the support beamis limited by engaging a concave groovethat is formed around the inside surface of the concave sectionin the circumferential direction around the support beamwith a protrusionthat is formed around the outer-circumferential surface of the support beam

Toroidal continuously-variable transmission

A trunnion of a toroidal-type continuously variable transmission has a support plate portion for supporting a displacement shaft and a pair of bent wall portions respectively bent toward the inner surface side of the support plate portion. The support plate portion and the pair of bent wall portions cooperates together in defining a pocket portion for storing a power roller therein. Pivot shafts are disposed concentrically with each other on the outer surfaces of the pair of bent wall portions. The pair of bent wall portions are connected together by a connecting member. The connecting member includes a pressure receive portion contactable with the inner surface of the pocket portion in a direction intersecting substantially at right angles to the thrust direction and receiving a pressing force acting on the pocket portion to crush the pocket portion.

Toroidal-type continuously variable transmission

A toroidal-type continuously variable transmission which includes: a casing; input and output disks respectively including inner surfaces, disposed concentrically with each other inside the casing, and supported so as to rotate independently of each other; a plurality of trunnions each including even-numbered pivot shafts existing at right angles to a central-axis direction of the disks and disposed concentrically with to in parallel to each other, and being swingable about the pivot shafts; a plurality of shift shafts respectively projected out from the trunnions; a plurality of power rollers held by and between respective inner surfaces of the disks so as to be rotatably supported on the shift shafts; and a support member fixed directly to the casing and supporting the pivot shafts so as to be shifted in an axial and an inclined rotation direction thereof.

A power roller bearing of a toroidal-type continuously variable transmission unit that is used for a transmission of an automobile or the like comprises a power roller, an outer race, balls, a retainer, etc. Annular raceway grooves are formed individually on the respective opposite end faces of the outer race and the power roller. Treated-surface layers for enhancing the endurance of the power roller bearing are formed individually on the respective surfaces of the raceway grooves. The treated-surface layers include super-finished surfaces with the surface roughness of 0.05 Rad or less, formed individually on the raceway grooves, and low-friction layers formed individually on the super-finished surfaces. Alternatively, the treated-surface layers include residual compression stress layers formed on the respective surface layer portions of the raceway grooves by shot-preening.

Power roller bearing of toroidal-type continuously variable transmission unit

An output side disk includes a penetration hole for penetration of an input shaft therethrough, and a securing groove formed in the inner peripheral surface of the penetration hole for preventing a needle roller bearing from slipping out in the axis O direction of the input shaft. The first connecting portion R of the securing groove is formed as a surface the section of which has an arc-like shape of a large radius of curvature, whereas the second connecting portion R of the securing groove is formed as a surface the section of which has an arc-like shape of a small radius of curvature.

A double-cavity toroidal-type continuously variable transmission includes a case, a drive shaft and a toroidal transmission mechanism portion. The toroidal transmission mechanism portion includes a gear housing for supporting an output gear, and a yoke for supporting a pivot shaft of a trunnion in an oscillatable manner. The support post for supporting the yoke and a fixing member for fixing the gear housing and the support post to the case are connected together or are formed as an integral body.

Double-cavity toroidal-type continuously variable transmission and method for assembling same

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

In the toroidal-type continuously variable transmission, the radial clearance of a second radial needle roller bearing for supporting the power roller on the periphery of the pivot shaft portion of the displacement shaft is set larger than the radial clearance of a first radial needle roller bearing for supporting a support shaft portion on a trunnion . By increasing the radial clearance of the second radial needle roller bearing in this manner, an increase in the surface pressures in the contact portions between the rolling surfaces of needle rollers and the inner peripheral surface of the power roller and the outer peripheral surface of the pivot shaft portion can be restricted, thereby enhancing the durability of the toroidal-type continuously variable transmission. Also, by reducing the radial clearance of the first radial needle roller bearing , the inclination of the displacement shaft is minimized, thereby stabilizing the rotation speed change operation thereof.

In a toroidal-type continuously variable transmission, at least one of components including inner and outer races of a power roller bearing, an input disk, and an output disk is composed of an alloy steel material containing C: 0.15 to 0.5 wt %, Si: 0.1 to 1.5 wt %, Mn: 0.1 to 1.5 wt %, Cr: 0.5 to 3.0 wt %, and at least one kind selected from Mo: 0.1 to 3.0 wt % and V: 0.1 to 3.0 wt %, a content of 0 in the alloy steel material being set to be not more than 9 ppm; and the surface of the at least one component after carbonitriding, hardening and tempering treatments is set to contain C: 0.8 to 1.2 wt % and N: 0.05 to 0.20 wt %, and the at least one component has surface hardness of Hv 720 or more, and Mo.V carbide/carbonitride, the average particle size of which is in a range of from 50 nm to 500 nm is dispersed and precipitated on a race surface or in a range of from the race surface to a deep position where a maximum shearing stress is generated.

In a toroidal-type continuously variable transmission, a plurality of trunnions is respectively swingable about a pair of mutually concentric pivot shafts through a plurality of radial needle roller bearings respectively supporting the pivot shafts. Each of the radial needle roller bearings includes: an outer race interposed between an outer peripheral surface of the pivot shaft and an inner peripheral surface of the circular hole of the support plate, the outer race having an outer peripheral surface formed in a spherically convex surface; and a plurality of needle rollers respectively disposed on the inside diameter side of the outer race. The outer race is formed with an inwardly facing flange portion on the inner peripheral surface of the end portion thereof.

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

In a toroidal-type continuously variable transmission, there is provided a thrust rolling bearing interposed between a power roller and a trunnion for supporting a thrust-direction load applied to the power roller. The thrust rolling bearing includes a plurality of rolling elements and a retainer rollably holding the plurality of rolling elements. The retainer defines a circular-ring-shaped main body and a plurality of pockets respectively formed in the main body for rollably holding the plurality of rolling elements. A clearance between the pocket and the rolling element is set in the range of 0.6 to 6.0% of the ball diameter of the rolling element.

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.

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Kanagawa, Japan

Nobuo Goto