Rotary shafts – gudgeons – housings – and flexible couplings for ro – Housing – Flexible housing
Reexamination Certificate
1998-08-14
2001-04-24
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Housing
Flexible housing
C277S637000, C403S381000
Reexamination Certificate
active
06220969
ABSTRACT:
FIELD OF INVENTION
This invention relates to universal joint seals and more particularly relates to a clampless boot for sealing a universal joint such as a constant velocity joint.
BACKGROUND OF THE INVENTION
In the early 1980's the automotive industry began to switch production from rear wheel drive vehicles to front wheel drive vehicles. Generally, front wheel drive passenger vehicles are now more common than rear wheel drive vehicles. This change resulted in a significant redesign of vehicle drive systems. Today, front wheel drive vehicles typically have two driveaxles, one to connect each front wheel with the vehicle transmission. In four wheel drive and independent rear suspension vehicles the automobile can have four driveaxles. Each driveaxle typically requires two constant velocity (CV) joints, a type of universal joint, to allow for movement of the driveaxles in relation to the transmission as the vehicle wheels encounter uneven terrain.
Because of the proximity of the CV joints to a highway or road, CV joints require a flexible ‘boot’, which is attached over the joint to protect it from stones, debris and other external contaminants while retaining lubricants and maintaining integrity of the precision internal bearing surfaces of the CV joint. It is well known in the prior art to use band clamps for the attachment of boots to CV joints, and crimp-style clamps have been the preferred means for attaching boots for the past decade. Crimp-style clamps have an outwardly projecting deformable crimp lug by which the clamp is installed, as described in U.S. Pat. No. 5,105,509. This method is favoured for its simplicity as a mechanical means to retain and seal the boot to the CV joint.
More recently, anti-lock braking systems (ABS) have been installed on vehicles to provide improved vehicle braking. Originally, such a safety device was mainly installed in higher priced vehicles, but ABS is now becoming a standard installation on many vehicles. On front wheel drive vehicles, anti-lock braking systems have an ABS wheel position ring encircling the CV joint adjacent the wheel, and an ABS sensor suspended from the vehicle chassis mounted proximate the position ring so as monitor wheel rotation. This location is disadvantageous as it is typically adjacent the crimp-style clamp affixing the boot. The positioning of the ABS sensor greatly reduces the amount of radial clearance available around the CV joint to which the crimp-style clamp is installed, creating a risk of interference between the crimped clamp and the ABS sensor. Such interference can damage the sensor during wheel rotation while the vehicle is operating. Similarly, affixing a crimp style clamp during a repair of the vehicle could result in inadvertent damage to the sensor and render the ABS inoperative.
The reduced clearance necessary for the ABS sensor has forced the development of lower profile crimps on crimp-style clamps. For example, Canadian Patent No. 1,286,094 discloses an earless or lugless clamp structure. However, at the original equipment manufacturer (O.E.M.) level these lower profile crimp style clamps can be only utilized when softer boot compounds are used, due to their inherent lower crimping loads. Generally, the use of a clamp results in greater complexity and cost in the assembly of the vehicle, and raise the likelihood of damage to the ABS sensor during replacement.
A further disadvantage to the use of clamps to affix boots to CV Joints has arisen due to new materials now used to manufacture boots. It is well known in the art to mould boots from neoprene, however, it has been determined that neoprene is susceptible to damage from heat from the vehicle's engine, which can lead to premature deterioration of the boot Silicone has also been commonly used, but more recently, Hytrel®, a product of Dupont Chemical Inc. is being used for its superior resilience to vehicle engine heat and imperviousness to debris and other environmental contaminants present on highways and other vehicle driving surfaces. While Hytrel® is proving to be a superior material for CV boots, it's properties require a high pressure to adequately secure the boot to the CV joint. Thus, in order to provide low profile clamps with sufficient crimping pressure, it is now commonplace to use a swage ring or compression ring as described in U.S. Pat. No. 5,768,752, which further increases the complexity of vehicle design and assembly.
It will be apparent that other universal joints can suffer from some of the foregoing disadvantages. For example, the rack and pinion steering unit universal joint is also located near to the vehicle driving surface, thereby necessitating a protective boot.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a novel means to attach a boot to a universal joint that obviates or mitigates at least one of the disadvantages of the prior art.
In a first, broadest aspect of the present invention a universal joint and boot assembly is provided. The universal joint is comprised of a first and second member engaging one another to transmit torque between the members. The first member has a circumferential groove formed on its exterior. The assembly also includes a boot for sealing the engagement between the first and second members of the universal joint The boot comprises a flexible hollow body with a continuous rib extending from an inner surface of the body, and the rib is formed in any suitable fashion so as to be received within the groove on the first member, such that the boot is sealed to the first member. The boot can be sealed to the second member using the aforementioned rib and groove configuration, or any other conventional means well known in the art can be used.
In a preferred embodiment of the first aspect of the present invention, the universal joint is a constant velocity joint, such as those commonly found on the driveshafts between the transmission and the front-wheels of a front wheel drive vehicle.
In another preferred embodiment of the first aspect, the rib on the boot comprises a rectilinear throat and an arrow-shaped head, and the groove on the first member of the universal joint comprises a wider portion complementary to the head and a narrow portion complementary to the throat.
In another preferred embodiment of the first aspect, the rib on the boot comprises a rectilinear throat and a cylindrical head, and the groove comprises a wider portion complementary to the head and narrow portion complementary to the throat.
In another preferred embodiment of the first aspect, the universal joint is a universal joint on a rack and pinion steering system. Such a universal joint is commonly the double-yoke style as is well known in the art, and it will be appreciated that the first member, ie. the first yoke, of the universal joint has suitable surface for a circumferential groove.
In a second broad aspect of the present invention, a boot for sealing a universal joint is provided. The universal joint has a first and second member for transmitting torque therebetween, and the first member has a circumferential groove. The boot comprises a flexible hollow body and a continuous rib extending from an inner surface of the body. The rib on the body is coincident with the groove when the boot is positioned on the universal joint, and the rib cooperates with the groove to maintain the boot in position on the universal joint.
In a third broad aspect of the present invention, a universal joint and boot assembly is provided. The universal joint comprises a first and second member engaging one another to transmit torque therebetween, and the first member has a circumferential rib. The boot for sealing the engagement between the first and second members has a flexible hollow body with a continuous groove in an inner surface of the body of the boot, and the rib is designed as as to be received in the groove such that said boot is sealed to the first member.
REFERENCES:
patent: 1871883 (1932-08-01), Geyer
patent: 1998791 (1935-04-01), Schanz
patent: 2283139 (1942-
Binda Greg
Browne Lynne H.
Gowling Lafleur Henderson Strathy
St. Louis Stamping Inc.
LandOfFree
Clampless universal joint and boot assembly does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Clampless universal joint and boot assembly, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Clampless universal joint and boot assembly will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2548644