Rotary shafts – gudgeons – housings – and flexible couplings for ro – Housing – Flexible housing
Reexamination Certificate
2002-05-02
2004-09-21
Bagnell, David (Department: 3672)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Housing
Flexible housing
Reexamination Certificate
active
06793584
ABSTRACT:
TECHNICAL FIELD
The present invention generally relates to constant velocity joints, and more particularly, relates to a labyrinth style vent for use in an constant velocity high-speed joint.
DESCRIPTION OF RELATED ART
Constant velocity joints (CV joints) are common components in automotive vehicles. Typically constant velocity joints are used where transmission of a constant velocity rotary motion is desired or required. The common types of constant velocity joints are plunging tripod, fixed tripod, a plunging ball joint and a fixed ball joint. These common types of constant velocity joints are either usually in a mono block style or disk style. These constant velocity joints currently are used in front wheel drive vehicles or rear wheel drive vehicles and on the propeller shafts found in rear wheel drive, all wheel drive and four-wheel drive vehicles. Plunging CV joints allow for axial movement during operation without the use of slip splines.
Constant velocity joints are generally grease lubricated for life and sealed by a boot. Thus, constant velocity joints are sealed in order to retain grease inside the joints while keeping contaminants and foreign matter, such as dirt and water, out of the joint. 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 a rubber, thermoplastic, silicone or other pliable material. The opposite end of the outer race is generally enclosed by a dome or cap, known as a grease cap in the case of a disk type joint. A mono block or integral stem and race design style does not use a grease cap. Instead it is sealed by the internal geometry of the outer race. The sealing and protection of the constant velocity joint is necessary because contamination of the inner chamber may cause internal damage and destruction of the joint. Furthermore, once the inner chamber of the constant velocity joint is lubricated, it is lubricated for life
During operation, the constant velocity joint creates internal pressure in the inner chamber of the joint. The higher the speeds that the constant velocity joint rotates at the greater these pressures become. These pressures have to be vented to the outer atmosphere in order to prevent pressure build up which occurs during operation of the joint and may destroy the boot. If the pressure build up is allowed to reach critical state, the boot may crack and have a blowout thus losing sealablity. Certain constant velocity joint designs are vented by placing a small hole generally in the center of the grease cap or at lease one hole around the outer periphery of the outer race. These prior methods of venting the gas are not completely reliable because if the constant velocity joint is in a static state and not rotating, the lubricating grease may migrate towards the vent hole and block or hinder its function of venting any internal gas pressure. This type of vent may also allow the infiltration of contaminants into the internal chamber of the constant velocity joint. Furthermore, the constant velocity joint has a tendency, after running for long periods of time, to create very high temperatures along with the high pressures which are vented through the prior art vent holes. However, if the constant velocity joint is submerged or saturated in water or other contaminants, the water or other contaminants will, via a pressure differential, be sucked into the constant velocity joint thus contaminating the grease and reducing the life of the constant velocity joint. Therefore, the introduction of water and other contaminants through the vent hole may reduce the life expectancy of the constant velocity joint.
Therefore, there is a need in the art for a constant velocity joint that will prevent the build up of internal gas pressure while eliminating the ingress of contaminants into the constant velocity joint. Furthermore, there is a need in the art for a vent that is low in cost, easy to manufacture and install on the constant velocity joint.
DISCLOSURE OF THE INVENTION
One object of the present invention is to provide an improved constant velocity joint.
Another object of the present invention is to provide a new vent solution for a constant velocity joint.
Yet a further object of the present invention is to provide a vent for a constant velocity joint that is capable of releasing gas under pressure to the atmosphere.
Still a further object of the present invention is to provide a vent that will prevent the entry of contaminants and water into the constant velocity joint inner chamber.
Yet a further object of the present invention is to provide a constant velocity joint that will vent and allow equalization of pressure internally from the constant velocity joint relative to the atmosphere along a shaft of the constant velocity joint.
To achieve the foregoing objects, a vent for a constant velocity joint is disclosed. The constant velocity joint vent includes a body generally having a cylindrical shape. The vent also includes a first axial channel on the inside surface of the body. A semi circumferential channel is in communication with the first axial channel on one end thereof. The vent also includes a second axial channel in communication with the semi circumferential channel on another end thereof. The vent also includes a diaphragm in communication with the second axial channel. The diaphragm allows for pressure to be released and also prevent the ingress of contaminants into the constant velocity joint.
One advantage of the present invention is that the constant velocity joint includes a vent that allows for equalization of pressure inside the constant velocity joint to the outer atmosphere.
A further advantage of the present invention is that the constant velocity joint vent will top the entry of contaminants into the constant velocity joint internal chamber.
Still a further advantage of the present invention is that the vent is specifically tuned to work at the high speeds of the constant velocity joint and still allows for the venting between the outside atmosphere and the internal chamber of the constant velocity joint.
Yet another advantage of the present invention is that the constant velocity joint vent is directly molded into the inside surface of the boot thus reducing the complexity of the manufacturing and installation of the vent feature.
Other objects, features and advantages of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4224808 (1980-09-01), Gehrke
patent: 4282722 (1981-08-01), Orain
patent: 4392838 (1983-07-01), Welschof et al.
patent: 4559025 (1985-12-01), Dore
patent: 6179717 (2001-01-01), Schwarzler
Miller Michael James
Ramey John A.
Bagnell David
Brumbaugh Jennifer M.
GKN Driveline North America, Inc.
Nylander Mick A.
Thompson K.
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