Hub Bearing Seal with Labyrinth Side Lip for Torque Reduction
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Solution Overview
Problem
Conventional sealing devices for hub bearing seals in motor vehicles experience torque increases and reduced sealing performance at high speeds due to sliding heat generation, leading to permanent deformation and muddy water intrusion when using radial lips, and omitting these lips compromises sealing effectiveness.
Innovation Solution
A sealing device with a combination of a first and second side lip, where the second side lip is positioned closer to the object of sealing and has a smaller interference allowance than the first side lip, and can be formed as a labyrinth structure with zero interference, to minimize torque and enhance sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a radial lip is used to seal against muddy water, then sealing performance is improved, but sliding heat generation increases causing permanent deformation at high speeds
Solution Approach 1:
The patent removes the radial lip (axial lip) from the seal structure to eliminate the source of excessive sliding heat generation. By extracting this problematic component, the seal can operate at high speeds without permanent deformation while maintaining sealing effectiveness through alternative means.
Solution Approach 2:
The patent changes the contact mechanism from peripheral surface contact (radial lip) to end surface contact (side lips). This parameter change in the sealing approach reduces the sliding heat generation while maintaining sealing performance against muddy water and dust.
2Temperature
If the radial lip is omitted to suppress sliding heat generation, then heat generation is reduced, but sealing performance against muddy water deteriorates
Solution Approach 1:
The patent divides the sealing function into multiple side lips positioned at different locations. The first side lip seals the gap between the seal member and slinger, while the second side lip seals the gap between the first side lip and slinger, collectively providing muddy water resistance without requiring a radial lip.
Solution Approach 2:
The first side lip acts as an intermediary element between the seal member and slinger, creating a sealing barrier that prevents muddy water intrusion. The second side lip then seals the gap between the first side lip and slinger, providing redundant sealing without direct contact that would generate excessive heat.
3Reliability
If a second side lip is added at the outer side of the first side lip with the same shape, then sealing performance is improved, but torque increases significantly reducing the benefit of omitting the radial lip
Solution Approach 1:
The patent applies different interference allowances to different side lips based on their specific sealing requirements. The first side lip has a larger interference allowance for primary sealing, while the second side lip has a smaller interference allowance sufficient for its secondary sealing function, optimizing the balance between sealing performance and torque.
Solution Approach 2:
The patent changes the interference allowance parameter for the second side lip to be smaller than that of the first side lip. This parameter optimization reduces the torque generated by the second side lip while maintaining adequate sealing performance, thereby preserving the benefits of omitting the radial lip.
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 configuration reduces torque and improves sealing performance by protecting the first side lip from foreign materials while maintaining effective sealing against muddy water and dust, thereby extending the service life of the seal.
Implementation Method 1
the second side lip 20 is formed as a labyrinth structure which is in non-contact with the axial end surface 33a of the flange portion 33 of the slinger 31
Implementation Method 2
a first side lip 19 slidably coming into close contact with an axial end surface of its mate member, and a second side lip 20 arranged closer to an object of sealing than the first side lip 19
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A sealing device (1) formed by combining a seal member (11) and a slinger (31), the seal member (11) having a first side lip (19) slidably in close contact with an axial end surface (33a) of the slinger (31), the seal member (11) further having a second side lip (20) disposed at a position that is on the outside of the first side lip (19) and is nearer an object to be sealed than the first side lip (19), wherein torque generated during the sliding is minimized as much as possible. To achieve this, the second side lip (20) is shaped so as to have smaller interference than the first side lip (19). The interference of the second side lip (20) may be set to zero by providing it with a labyrinth structure in which the second side lip (20) is not in contact with the axial end surface (33a) of the slinger (31).