Ntn Corporation

Junichi Izumino

Minoru Ishijima

Kenta Yamazaki

Kenji Konaka

Hisaaki Kura

Kenji Terada

Akira Sera

Manabu Hoshino

Shunsuke Makino

Jiahua Miao

Hiroshi Murakami

A manufacturing method for a tripod type constant velocity universal joint includes, when forging a raw-shaped material corresponding to each of three journals into a journal shape using a molding surface of a die and in a state where a relief portion is provided on a raw-shaped-material-leading-end-side of the die, molding an outer peripheral surface of the raw-shaped material into a projected round shape. The molding occurring with a tapered surface formed on the molding surface with which the outer peripheral surface of the raw-shaped material is held in contact and a recessed round surface formed between the molding surface and the tapered surface.

Tripod type constant-velocity universal joint and method for producing the same

A tripod-type constant-velocity universal joint has a journal raw profile with reduced weight and a reduced number of manufacturing steps. A leading end corner portion of the journal raw profile is held with use of a die and forged. By the forging, at the part including an elliptically longitudinal side relatively on a leading end portion side of an outer peripheral surface of each of journals, edge portions reducing a lateral sectional area of each of the journals toward a leading end side thereof are formed, and tapered surfaces are formed on the leading end side of the edge portions. Centering on each of the journals is performed by causing two points on an elliptically longitudinal side of the edge portions to abut against a centering jig.

Tripod-type constant-velocity universal joint and method of manufacturing the same

A fixed constant velocity universal joint of a structure, which easily allows incorporation of an inner ring into a cage without impairing a function of the joint, is provided. The fixed constant velocity universal joint has an outer ring having in an inner spherical surface thereof a plurality of track grooves arranged at equal circumferential intervals and extending axially toward an open end, an inner ring having in an outer spherical surface thereof a plurality of axially extending track grooves paired with the track grooves of the outer ring and arranged at equal circumferential intervals, a plurality of balls interposed between the track grooves of the outer ring and the track grooves of the inner ring, for transmitting torque, and a cage interposed between the inner spherical surface of the outer ring and the outer spherical surface of the inner ring, for holding the balls, in which an outer ring open end side of the outer spherical surface of the inner ring is cut off, with a boundary portion between a cutoff portion thereby obtained and the outer spherical surface being rounded.

Fixed constant velocity universal joint

A tripod constant velocity universal joint includes among others an inner joint member having a bossand journalsradially protruding from the boss, a radius of curvature Ras viewed in a cross section of a journal bottom partconnecting the bossto the journaland as measured at opposing locations in a circumferential direction of the joint is larger than a radius of curvature Rof the journal bottom part as viewed in its cross section and as measured at opposing locations in an axial direction of the joint and Rgradually decreases down to R.

Tripod constant velocity universal joint

In a tripod type constant velocity joint, in order to produce a recovery couple to correct the inclination of the rolling direction of a roller and to reduce surface pressure without using angular contact provided by a Gothic arch-shaped roller guide surface, it is arranged that where rand rare the minimum and maximum values, respectively, of the radius of curvature of the generatrix for the outer peripheral surface of the roller within the range where solid contact is effected by elastic deformation of the contact section between the roller and the roller guide surface under a predetermined torque load with respect to the radius of curvature of the roller guide surface, the radius of curvature (r) of the generatrix be set in the range r&#x2266;r&#x2266;r

Tripod type constant velocity joint

A tripod type constant velocity joint including a hollow cylindrical housing fixed to the end of a first rotary shaft and formed with axially extending recessed grooves opened at one axial end and located at circumferentially trisectional positions on the inner peripheral surface, a tripod consisting of a boss fixed to the end of a second rotary shaft, and end-spherical trunnion journals radially projecting from circumferentially trisectional positions on the boss, and roller assemblies each consisting of an inner roller swingably fitted at the inner peripheral surface thereof on the spherical outer peripheral surface of the trunnion journal, and an outer roller supported for rotation and axial movement on the outer peripheral surface of the inner roller through needle rollers, wherein the outer rollers are received in the recessed grooves in the housing and are rollable axially of the housing.

A tripod type constant velocity universal joint that includes an outer joint member having three track grooves axially extending on an inner circumferential surface thereof; an inner joint member having three radially projecting trunnions; a boot fitted to an outer periphery of the outer joint member at an end portion and to a shaft extended from the inner joint member at another end portion to seal an inner region of the joint; wherein the outer joint member includes a first reduced-thickness portion on an outer periphery thereof in a region corresponding to the region between the track grooves, and a second reduced-thickness portion on an outer periphery thereof in a region corresponding to the region where the track grooves are located; and wherein the second reduced-thickness portion is of a groove shape axially extending with respect to the outer joint member.

Tripod type constant velocity universal joint

The present invention provides a lightweight, compact, and low-cost tripod type constant velocity universal joint while maintaining strength of overall tripod type constant velocity universal joint. The dimensional ratio of each component of the tripod type constant velocity universal joint is set as follows: 0.80&#x3c;Dor&#x3c;0.90, 0.105&#x3c;Tor&#x3c;0.115, 0.025&#x3c;fir&#x3c;0.045, 0.025&#x3c;t&#x3c;0.075, 0.53&#x3c;Dir&#x3c;0.63, 0.065&#x3c;Tir&#x3c;0.085, 0.32&#x3c;Dj&#x3c;0.42, and 0.32&#x3c;Dj&#x3c;0.35. In this event, the subscript 'r' means that each dimension is divided by the trunnion journal pitch circle diameter D (=PCD) of the joint.

A tripod type constant velocity joint comprising a hollow cylindrical housing fixed to the end of a first rotary shaft and formed at the inner peripheral surface thereof with axially extending recessed grooves opened at one axial end and located at circumferentially trisectional positions on the inner peripheral surface, a tripod consisting of a boss fixed to the end of a second rotary shaft, and end-spherical trunnion journals radially projecting from circumferentially trisectional positions on the boss, a roller assemblies each consisting of an inner roller swingably fitted at the inner peripheral surface thereof on the spherical outer peripheral surface of the trunnion journal, and an outer roller supported for rotation and axial movement on the outer peripheral surface of the inner roller through needle rollers, wherein the outer rollers are received in the recessed grooves in the housing and are rollable axially of the housing, each recessed groove consists of guide surfaces contacting the outer peripheral surface of the outer roller and subjected to loads, and guide shoulder surfaces for guiding the outer roller axially of the housing, and only the side of the outer diameter of said boss associated with the end of the second rotary shaft is heavily chamfered. A relief is locally formed along the forged parting line of the trunnion journal. The root of the tripod journal is of non-circular cross-section in which the diameter as measured circumferentially of the joint is larger than the diameter as measured axially of the joint.

A fixed constant velocity joint is provided, which is suitable for an application where a rotational backlash should be avoided. A pressing member is attached to a shaft, and simultaneously a receiving member is attached to a cage. Then, an elastic force of an elastic member elastically bring a pressing part of the pressing member in contact with a receiving part of the receiving member. As a result, an inner race and a cage relatively travel in the axial direction, balls are pushed toward a direction along which wedge-shape ball tracks narrow, and consequently a track clearance in the axial direction decreases.

Fixed constant velocity joint

Tripod type constant velocity joint has a hollow cylindrical housing fixed to the end of a first shaft and has axially extending recessed grooves opened at one axial end and located at circumferentially trisectional positions on an inner peripheral surface. A tripod has a boss fixed to the end of a second shaft with end-spherical trunnion journals radially projecting from circumferentially trisectional positions on the boss. Roller assemblies each have an inner roller fitted on the spherical surface of the trunnion journal and an outer roller supported for rotation and axial movement on the inner roller. The outer rollers are received in the recessed grooves and rollable axially of the housing. Each recessed groove has guide surfaces contacting the outer surface of the outer roller. Guide shoulder surfaces guide the outer roller axially of the housing. A relief is locally formed along a forged parting line of the trunnion journal.

A tripod type constant velocity universal joint that can suppress generation of shudder by reducing the 3rd order cyclic axial force and has high rotation durability. In a double-roller tripod type constant velocity universal joint, a track gap &#x3b4;between one of the roller guiding surfaces formed on both sides of a track groove, which is on the no-load applied side, and an outer circumferential surface of an outer roller is set to satisfy &#x3b4;0.03/A. Also, a shoulder gap &#x3b4;between a guide shoulder surface formed at the bottom of the track groove and a side surface of the outer roller is set to satisfy &#x3b4;0.15&#xd7;A. In both the expressions, a degree of torus A is defined as a ratio of a radius of curvature r of a generatrix of the outer circumferential surface to a radius R of an outer circumference of the outer roller (A=r/R).

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Shizuoka-ken, Japan

Junichi Izumino