Rotary shafts – gudgeons – housings – and flexible couplings for ro – Coupling accommodates drive between members having... – Coupling transmits torque via radially spaced ball
Reexamination Certificate
2000-06-09
2001-04-24
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Coupling accommodates drive between members having...
Coupling transmits torque via radially spaced ball
C464S139000, C464S906000
Reexamination Certificate
active
06220967
ABSTRACT:
TECHNICAL FIELD
This invention relates to an improved venting constant velocity universal joint and specifically to a constant velocity joint vent plug.
BACKGROUND ART
Constant velocity universal joints are well known in the art and are employed where transmission of a constant velocity rotary motion is desired or required. The tripod joint is characterized by a bell-shaped outer race (housing) disposed around an inner race.
One common type of constant velocity universal joint is a fixed or Rzeppa style. Fixed constant velocity joints are generally grease lubricated for life and sealed by an elastomeric sealing boot when used on some drive shafts. Most constant velocity universal joints are sealed in order to retain grease inside the joint while keeping contaminants and foreign matter, such as dirt and water, out of the joint. In order to achieve this protection, the constant velocity joint is usually enclosed at the open end of the outer race by a sealing boot made of rubber, thermoplastic or urethane. Such sealing and protection of the constant velocity joint is necessary because, once the inner chamber of the outer joint is partially-filled and thus lubricated, it is generally lubricated for life.
It is often necessary to vent the constant velocity joint in order to minimize air pressure fluctuations due to expansion and contraction of the air within the joint during operation of the joint. Further, in some circumstances the constant velocity joint boot may “blow out” or rupture during high speed operation. Venting is required when using a rubber material for the boot.
U.S. Pat. No. 4,319,467 issued to Hegler et al. discloses a seal vent subassembly press fitted into the collar bore of a universal joint. The subassembly includes a vent disc which is nested in a seal disc to form a venting arrangement to the exterior of the housing by way of various holes and chambers. However, this vent hole may still be subject to grease buildup during a static state or operative state.
U.S. Pat. No. 6,010,409, issued to GKN Automotive, Inc. discloses a vent regulator device adapted for use in a constant velocity joint including a housing having an inner surface defining an inner cavity. The inner surface includes an annular portion, and a domed portion which has a relatively small vent hole centrally located therein. The vent regulator device further includes a member having a first end and a second end where the first end is mounted to the inner surface of the housing and the second end is disposed proximate the vent hole. When the constant velocity joint is in one of either a static state and an active state rotating at speeds below a predetermined threshold, the vent hole is overlappingly covered by the first end of the member, thereby preventing grease from penetrating the hole. Moreover, when the constant velocity joint is in an active state rotating at speeds above the predetermined threshold, centrifugal forces cause the second end of the member to move away radially from the vent hole to allow venting of air therethrough.
Consequently, an improved constant velocity joint design is provided which allows for reliable venting of the joint when large quantities of grease are contained therein. In addition, the design should eliminate grease flow out of the joint and not allow any foreign matter into the joint.
BRIEF SUMMARY OF THE INVENTION
It is an object according to the present invention to provide a system for venting a constant velocity joint without a loss of grease or other internal joint lubricant.
It is still a further object according to the present invention to provide a constant velocity joint which includes a vent plug for effectively venting the joint.
In carrying out the above objects, features and advantages of the present invention, provided is a vent plug for use with a universal joint having an outer race including a vent aperture, the vent plug comprising an elongate body portion having a first end and a second end, a retention cap disposed adjacent the first end and a vent cavity extending from the first end to the second end, the elongate body having a rigid outer surface receivable within the vent aperture, wherein the retention cap includes an escape aperture in communication with the vent cavity allowing the universal joint to vent internal pressure during high speed operation.
It is still a further object according to the present invention to provide a venting constant velocity joint system including a constant velocity joint having an outer race and an inner race, the outer race having an outer wall, an inner wall and a back wall, the inner race defining a vent aperture extending from the outer wall to the inner wall, a vent plug having an elongate body portion including a first end and a second end, a retention cap disposed adjacent the first end and a vent cavity extending from the first end to the second end and located between the back wall and the inner race, the elongate body having a rigid outer surface receivable within the vent aperture wherein the retention cap includes an escape aperture in communication with the cavity allowing the universal joint to vent internal pressure during operation.
It is yet another object of the present invention to provide a venting constant velocity joint system with a vent plug having an elongate body including a retention lip disposed between the first end and the second end of the elongate body for use in retaining the vent plug within the vent aperture.
It is still another object of the present invention to provide a venting constant velocity joint which prevents the entry of outside contaminants.
It is another object of the present invention to provide a venting constant velocity joint system of having a vent plug with an escape aperture defined by a slit having a width in a range from 0.10 millimeters to 0.20 millimeters, a length from 3 millimeters to 5 millimeters and a height from 0.5 millimeters to 1.0 millimeters.
It is another object of the present invention to provide a venting constant velocity joint system of wherein the vent plug is manufactured from thermal plastic elastomer with a durometer hardness in a range from 70 to 120.
It is another object of the present invention to provide a venting constant velocity joint system of wherein vent plug extends downwardly into the constant velocity joint at least to the centerline of the constant velocity joint.
It is still another object of the present invention to provide a venting constant velocity joint system with a vent plug having retention lip with a frustoconical section and an engagement surface whereby the engagement surface contacts the inner wall of the outer race and the retention cap engages the outer wall of the outer race such that the vent plug is retained within the outer race.
In high speed operation a venting of the constant velocity universal joint is useful in relieving internal pressure created by the grease volatility caused by sometimes high internal operating temperatures. In operation, when the constant velocity universal joint is in operation, internal pressure is continually relieved as air passes through the slit
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to the atmosphere thereby stabilizing pressure between the joint and outside atmosphere.
It is yet another object of the present invention to provide a venting constant velocity joint having an outer race with an inner wall which defines an first angle and said retention lip engagement surface defines a second angle which is substantially equal to said first angle.
The above objects and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.
REFERENCES:
patent: 3488979 (1970-01-01), Croset
patent: 4319467 (1982-03-01), Hegler
patent: 4893608 (1990-01-01), Reaser
patent: 5704838 (1998-01-01), Teale
patent: 6010409 (2000-01-01), Johnson
patent: 6042479 (2000-03-01), Hopson et al.
Browne Lynne H.
Dunwoody Aaron
GKN Automotive Inc.
Nylander Mick A.
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