Ntn Corporation

Kisao Yamazaki

Masazumi Kobayashi

Kenta Yamazaki

Minoru Ishijima

Hiroyasu Hirukawa

Tohru Nakagawa

Tomoshige Kobayashi

Katsuhiro Sakurai

Hiroshi Kawamura

Hisaaki Kura

Masahiro Ozawa

Yuichi Asano

Teruaki Fujio

Shin Tomogami

Kiyoshige Yamauchi

Aiko Ishikawa

Taku Itagaki

Yoshinori Terasaka

A fixed type constant velocity universal joint has an outer joint member including first track groove portions and second track groove portions. Each of the first track groove portions includes an arc part having a curvature center that is not offset in an axial direction with respect to a joint center. The first track groove portions are inclined in a peripheral direction of the outer joint member with respect to a joint axial line and adjacent to each other in the peripheral direction with inclination directions opposite to each other. Each of the second track groove portions has a different shape than the first track groove portions. Each of the first track groove portions and each of the second track groove portions are connected to each other at a position on an opening side with respect to the joint center.

Fixed type constant velocity universal joint

Track grooves of an outer joint member include first and second track groove portions. Each of the first track groove portions is formed into an arc shape having a curvature center at a position offset to an opening side with respect to a joint center. The first track groove portions are inclined in a peripheral direction of the outer joint member with respect to a joint axial line and adjacent to each other in the peripheral direction with their inclination directions opposite to each other. Each of the second track groove portions includes a linear part and is connected to the each of the first track groove portions at a position on the opening side with respect to the joint center. Track grooves of inner and outer joint members are formed to be mirror-image symmetrical with respect to a joint center plane at an operating angle of 0&#xb0;.

Fixed type constant-velocity universal joint

In a fixed type constant velocity universal joint, track grooves of an outer joint member include first track groove portions positioned on an interior side and second track groove portions positioned on an opening side. The first track groove portions each have an arc-shaped ball raceway center line having a curvature center that is prevented from being offset in an axial direction of the outer joint member with respect to a joint center. Planes each including at least the ball raceway center line and the joint center are inclined with respect to a joint axial line with their inclination directions alternately opposite to each other in the first track groove portions that are adjacent to each other in a peripheral direction of the outer joint member.

In a fixed type constant velocity universal joint, track grooves of an outer joint member include first and second track groove portions positioned on interior and open sides, respectively. Each of the first track groove portions includes an arc-shaped ball raceway center line having a curvature center prevented from being offset in an axial direction of the outer joint member with respect to a joint center. Planes each including at least the ball raceway center line and the joint center are inclined with respect to a joint axial line with their inclination directions opposite to each other in the first track groove portions, which are adjacent to each other in a peripheral direction of the outer joint member. Each of the second track groove portions includes a ball raceway center line having a straight part when being projected onto corresponding one of the planes.

A fixed type constant velocity universal joint includes an outer joint member, an inner joint member, a plurality of balls for transmitting torque provided between track grooves of the outer joint member and track grooves of the inner joint member, and a cage for retaining the balls. Grease is enclosed in the fixed type constant velocity universal joint which includes a thickener and a lubricant component which is constituted by base oil. The grease contains 90% by mass or more of paraffinic mineral oil with respect to the total mass of the lubricant component of the grease, and 3 to 8% by mass of the thickener with respect to the total mass of the components of the grease.

A fixed type constant velocity universal joint has track grooves of an outer joint member including first and second track groove portions located on depth and opening sides, respectively. The first track groove portions each have a circular-arc part having a curvature center that is not offset in an axial direction with respect to a joint center, are inclined in a circumferential direction with respect to a joint axial line, and are adjacent to each other in the circumferential direction with their inclination directions opposite to each other. The second track groove portions have a different shape than the first track groove portions to increase an effective track length with respect to a maximum operating angle. The first and second track groove portions are connected respectively to each other on the opening side with respect to the joint center.

Fixed constant velocity universal joint

A constant velocity universal joint has track shapes which facilitate quality control on a forging die set, securing higher durability through securement of a stable contact state of forging-molded tracks and finishing-processed tracks with respect to balls. At least one of each of track grooves of an outer joint member and each of track grooves of an inner joint member is formed by cold-forging finishing. A track groove bottom side of the at least one of each of the track grooves is formed into a Gothic arch shape in horizontal cross-section, and a track groove opening side of the at least one of each of the track grooves is are each formed into an elliptical shape in horizontal cross-section.

Constant velocity universal joint

An outer joint member for a fixed type constant velocity universal joint contributes to the reduction of the number of man-hours through the reduction of the number of processes after a forging process, to an increase in yield, and to the reduction of manufacturing cost. The outer joint member is made of machine-structural carbon steel. The portions of the outer joint member that are finished by cold forging are track grooves, radially inner spherical-surface portions, a cup-inlet chamfer, track chamfers, track-inlet chamfers, a part except for a boot fixing portion on a radially outer surface of the cup section, and a center hole at an end surface of the shaft section.

Outer joint member for fixed constant velocity universal joint

A constant velocity universal joint having a recess-projection engagement configuration in which backlash at a shaft connecting region does not easily occur, and an inner joint component and a shaft can he firmly connected. hi the constant velocity universal joint, the inner joint component and the shaft () fitted into an axis hole () of the inner joint component are connected by die recess-projection engagement configuration. Engagement contacting regions () of projections () and recesses () corresponding thereto are in close contact over the whole region.

A fixed type constant velocity universal joint includes an outer joint member, an inner joint member, a plurality of balls interposed between the outer and inner joint members, and a cage to hold the plurality of balls. At least one of the plurality of track grooves of the outer joint member and the plurality of track grooves of the inner joint member is formed by cold-forging finishing. The outer joint member, the inner joint member, the balls, and the cage are assembled to each other based on matching in which the plurality of balls and the cage each having a rank corresponding to a measured value of a pitch circle diameter of the outer joint member and to a measured value of a pitch circle diameter of the inner joint member, which have been arbitrarily selected, are selected with respect to the arbitrarily selected outer and inner joint members.

Fixed constant velocity universal joint, method of manufacturing fixed constant velocity universal joint, and bearing device adapted for use in driving wheel and using fixed constant velocity universal joint

A fixed type constant velocity universal joint has cutout round portions () provided at two portions of a ball-contact-point corresponding part on a track inlet end () of each of the track grooves () of the outer joint member for reduce biting of balls. The fixed type constant velocity universal joint is capable of achieving reduction of stress generated when balls and edge portions interfere with each other, suppression of chipping of the edge portions, and prolongation of a service life of the joint as a whole. These advantages are achieved even at a time of an unexpected high-angle operation, and in particular even when an angle expected during use of the constant velocity universal joint is exceeded.

Fixed-type, constant-velocity universal joint

A fixed type constant velocity universal joint secures smooth rotation and reduces a load on a cage even at a large operating angle and when bearing large torque. The universal joint includes an outer joint member having an inner spherical surface in which track grooves are circumferentially formed in an axial direction and an inner joint member having an outer spherical surface in which track grooves paired with the track grooves of the outer joint member are circumferentially formed in the axial direction and multiple outer spherical surface portions circumferentially arranged. Balls are interposed between the track grooves of the outer and inner joint members for transmitting torque. A cage is interposed between the inner spherical surface and the outer spherical surface for retaining the balls. A spherical surface angle of the outer spherical surface on a joint opening side is set to 12.5&#xb0; or more.

A light and compact slide-type constant velocity universal joint has a maximum operating angle of 30&#xb0; or more through optimization of a ball contact angle relative to ball grooves, a ball contact ratio, and a cage offset amount. In the slide-type constant velocity universal joint, a ratio of ball diameter to outer ring outer diameter is 0.21 to 0.25, a ratio of ball pitch diameter to outer ring outer diameter is 0.64 to 0.68, a contact angle of the ball groove is 30&#xb0; to 35&#xb0;, a contact ratio of the ball groove is 1.02 to 1.08, and a ratio of cage offset amount to ball pitch diameter is 0.07 to 0.09.

Slide-type constant velocity universal joint

An inner ring is configured to simultaneously ensure the strength thereof and the dimensional accuracy of a female spline portion of a shaft hole thereof in the case where the female spline portion is subjected to heat treatment. Also it is configured to suppress the backlash of spline fit with a shaft. The inner ring is mounted in a constant velocity universal joint for transmitting torque while the inner ring is allowed to be angularly displaced relative to an outer ring and is spline-fitted to a shaft inserted into a shaft hole formed through the inner ring. The inner ring has a hardened layer by means of heat treatment which is formed only in an axial central portion of the shaft hole, but is not formed in remaining inner diameter surface other than the axial central portion.

Constant velocity universal joint and inner member thereof

A technique for improving a strength, especially a fatigue strength of a power transmission shaft provided with a serrated portion for torque transmission such as a spline shaft. A power transmission shaft is serration-fitted to an inner joint member of respective constant velocity joints. A driveshaft is provided with a serrated portion as well as a smooth portion having a cylindrical outer circumferential surface. A cut-up portion is formed at the end portion of the serrated portion. When applying an induction hardening to the smooth portion and the serrated portion, a hardening ratio of the smooth portion is set at a different value from that of the serrated portion, and such that a fatigue strength of the smooth portion becomes equal to or greater than that of the serrated portion.

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Iwata, Japan

Kisao Yamazaki