Joint Seal Speed-Controlled Ventilation for CVJ Pressure Management
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Solution Overview
Problem
Existing constant velocity universal joint sealing systems face challenges in managing ventilation to prevent pressure buildup and water/dirt ingress, especially under increased temperature and off-road conditions, without compromising the structural integrity of the shaft journal and convoluted boot.
Innovation Solution
A speed-controlled ventilation system is integrated into the joint seal, utilizing axial slots between radially elastic fingers and a sealing lip that changes shape under centrifugal force, allowing for pressure release at high speeds while maintaining a sealed condition at low speeds, eliminating the need for longitudinal grooves or channels in the shaft journal and collar.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If longitudinal grooves or channels are provided in the shaft journal or collar for ventilation, then pressure release is enabled, but the structural integrity and carrying cross-section of the shaft journal is weakened
Solution Approach 1:
The ventilation function is extracted from the shaft journal structure by using the slots between the axial fingers of the securing sleeve instead. This eliminates the need for grooves or channels in the shaft journal, preserving its structural integrity while still providing pressure release capability through the alternative ventilation path provided by the finger slots.
2Stress or pressure
If a ventilation system is added to the joint seal, then pressure control is improved, but the device complexity increases
Solution Approach 1:
The ventilation system is merged with the existing axial securing sleeve structure by utilizing the slots between its axial fingers. The sealing lip on the rolling boot is integrated with the same structure that provides axial securing. This combination eliminates the need for separate ventilation components, reducing overall device complexity while maintaining effective pressure control.
Solution Approach 2:
The axial securing sleeve serves multiple functions: it provides axial securing of the constant velocity universal joint, creates ventilation channels through its axial fingers, and works with the sealing lip to provide both sealing and pressure release. This multi-functionality reduces the number of separate components needed, simplifying the overall device structure.
3Stress or pressure
If the sealing lip is designed to lift off at increased speed, then pressure release is enabled, but the sealing effectiveness at low speed may be compromised
Solution Approach 1:
The sealing lip is designed with dynamic characteristics that allow it to change its sealing engagement based on operating conditions. At low speeds, the lip maintains contact with the shaft journal surface for effective sealing. At increased speeds, centrifugal forces cause the lip to lift off, enabling pressure release. This dynamic behavior ensures both sealing effectiveness and pressure control are achieved under different operating conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides a cost-effective and operationally safe sealing system that maintains the structural integrity of the shaft journal and convoluted boot, effectively preventing water and dirt ingress during low-speed operations while allowing pressure release at higher speeds, ensuring reliable performance in varying conditions.
Implementation Method 1
At an increased speed, the sealing lip, under the influence of the centrifugal force, can deform itself from the conical shape to a more pronounced radial planar shape, so that there is freed an annular gap from where the free ends of the slots can be connected to the environment.
Implementation Method 2
axial fixing of the constant velocity universal joint relative to the shaft journal is effected by an axial securing sleeve which is connected to the inner joint part and which ends in individual axial fingers which radially elastically engage an annular groove in the shaft journal
Data Source
AI summary
A joint seal of a constant velocity universal joint which has a sealing effect relative to a shaft journal includes an axial securing sleeve which is connected to the inner joint part and which ends in individual axial fingers which radially elastically engage an annular groove in the shaft journal, wherein the ventilation channels for the joint interior of the constant velocity universal joint are formed by axial slots between the individual axial fingers which freely end in the interior of the rolling boot and can be closed towards the outside of the rolling boot by a sealing lip which is formed on to the rolling boot, which, in the position of rest, annularly sealingly contacts the shaft journal and which, at an increased speed, lifts off the shaft journal to expose the ventilation channels.