Rotary shafts – gudgeons – housings – and flexible couplings for ro – Coupling accommodates drive between members having... – Tripod coupling
Reexamination Certificate
1998-08-24
2001-01-23
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Coupling accommodates drive between members having...
Tripod coupling
Reexamination Certificate
active
06176786
ABSTRACT:
TECHNICAL FIELD
This invention relates to an improved design for a tripod-type constant velocity universal joint.
BACKGROUND ART
Constant velocity universal joints are couplings used in automobiles to allow a rotational speed to be transmitted from a driving to a driven shaft which are not angularly aligned. One type of constant velocity universal joint commonly used in today's automobiles is the tripod universal joint. Tripod-type universal joints are characterized by a housing disposed around an inner joint which has a plurality of arms projecting therefrom for traveling in the grooves of the housing. A common feature of tripod universal joints is their plunging or end motion character. Plunging tripod universal joints allow the interconnection shafts to change length during operation and are currently the most widely used inboard (transmission side) joint in front-wheel drive vehicles.
The various types of tripod universal joints utilized today are often characterized by the different methods available for connecting or attaching tripod arms to the inner joint member. One variety of tripod joint exists in the art wherein a “spider” is splined to a drive shaft, the spider being an annular ring having three arms integrally formed thereon. At the upper portion of each arm, a trunnion is rotatably supported for riding in the grooves of the housing.
For background purposes, another method of tripod joint arm connection is shown by way of example in U.S. Pat. No. 4,384,860 (“the '860 patent”) issued to Schmid. The '860 patent shows a constant velocity joint having a female joint half with three axial grooves. As disclosed therein, a trunnion is placed in each groove for making rolling contact against the sides of the grooves. Each trunnion has a turnpin for turningly supporting the rollers in a male joint half. It is this variety of tripod joint to which the teachings according to the present invention may be applied.
During articulation and angular movement of a constant velocity joint of the type disclosed in the '860 patent, movement of the joint components may result in sliding friction, particularly on the turnpins with respect to the male joint half. Further, due to the rotational movement of the turnpin in the male joint half, a constant velocity joint of this variety may sometimes experience noise, vibration and harshness, as well as shuddering, during operation. However, the '860 patent does not resolve these issues.
Consequently, an improved constant velocity joint design is desired for tripod joints having a female joint half, better known in the art as an outer joint or outer race, and a male joint half, which is commonly referred to in the art as an inner joint. This type of joint has trunnions which are supported within the male joint half. Such an improved design should seek to correct or alleviate any noise, vibration and harshness in this type of joint, as well as lessen any shuddering experienced during operation. Further, such an improved design should also reduce any sliding friction which may result from the radial movement and rotational movement of the turnpin with respect to the male joint half during operation.
BRIEF SUMMARY OF THE INVENTION
It is an object according to the present invention to provide a tripod constant velocity joint of the male and female joint halves variety which exhibits reduced or negligible noise, vibration and harshness characteristics during operation.
It is another object according to the present invention to provide a tripod constant velocity joint which exhibits reduced or negligible shuddering during operation.
It is a further object according to the present invention to provide a tripod constant velocity joint which exhibits reduced sliding friction as the turnpins, or arms, are slidingly and radially moved in the inner joint.
It is a still a further object according to the present invention to provide a tripod constant velocity joint which accommodates endwise movement within the joint itself with a minimum of frictional resistance since the arms are themselves supported on the inner joint by needle roller bearings.
In carrying out the above objects, features and advantages according to the present invention, the invention provides a tripod universal joint assembly having a substantially annular outer race with three circumferentially distributed and longitudinally extending recesses. These recesses are parallel to the longitudinal axis of the outer race. Further provided is an inner joint member disposed within the outer race which has three circumferentially distributed radial bores formed therein. These bores define a centrally disposed cavity therebetween. A plurality of arm members each having a cylindrical body portion is disposed in a respective radial bore. Each arm member has a head portion which projects from the inner joint member out of the bore for engaging a respective recess of the outer race. There is further provided in the tripod universal joint assembly a spherical member disposed in the cavity of the inner joint for maintaining engagement of the head portion to the recess during articulation of the tripod universal joint.
The tripod universal joint according to the present invention further includes a plurality of annular bearing assemblies, each being disposed between the cylindrical body portion of the arm member and its respective radial bore. Each annular bearing assembly provides a bearing contact surface for the radial and rotatable movement of each arm member with respect to its respective adjacent radial bore.
In a preferred embodiment, each roller assembly of the tripod universal joint includes a plurality of needle roller bearings which provide a bearing contact surface between the cylindrical body portion of the arm member and its respective adjacent radial bore. In another preferred embodiment, an annular cage is provided which supports the plurality of needle roller bearings.
In another embodiment, provided according to the present invention is a constant velocity tripod joint which has an outer joint with an inner surface having three circumferentially equispaced axis-parallel tracks. Also included is an inner joint which is disposed within the outer joint and has a star-shaped cross section. The inner joint has three radially extending bores and a centrally disposed cavity located therein. Further included is a plurality of arm members each disposed in a corresponding bore and having a head portion projecting therefrom. Each head portion engages a corresponding track of the outer joint. Each arm member is rotatably and radially movable relative to the inner joint.
A plurality of annular roller assemblies is included, each assembly being rotatably disposed on a corresponding arm. Each annular roller assembly includes a plurality of needle bearings which is supported by an annular cage. While the annular cage directly engages its respective bore, each plurality of needle bearings engages its respective arm member, thereby providing a bearing surface between the arm member and the bore. Moreover, there is also included a controlling member which is disposed in the cavity of the inner joint and controls the radial movement of each arm member. Preferably, the controlling member is a spherical body such as a ball. In still another embodiment, the head portion of each arm member is trunnion-like and, in other words, has a partial spherical exterior surface for engaging a corresponding track of the outer race. Still in another preferred embodiment, the inner joint has a shoulder portion formed therein for supporting each annular roller assembly in its corresponding bore.
REFERENCES:
patent: 1172964 (1916-02-01), Evans
patent: 3930378 (1976-01-01), Schmid
patent: 4384860 (1983-05-01), Schmid
patent: 5728004 (1998-03-01), Dziegielewski
patent: 2750854 (1978-05-01), None
patent: 350954 (1905-06-01), None
patent: 2141208 (1984-12-01), None
Binda Greg
Browne Lynne H.
GKN Automotive Inc.
Nylander Mick A.
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