Bearing Cap Venting for Pressure Control
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Solution Overview
Problem
The existing hub bearing designs for driven wheels face issues with high internal pressure during the attachment of the protective cap, leading to increased rotary torque, reduced sealing effectiveness, and potential oblique attachment, which can affect the accuracy of antilock brake systems (ABS) and increase fuel consumption.
Innovation Solution
A cap for the bearing device with a cylindrical part and a lid part, featuring an annular seal and ventilation parts such as through holes or notches, which allow air to escape during fitting, preventing pressure buildup and ensuring proper sealing without obstructing the sealing function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the protective cap is press-fitted into the outer race member to maintain strength and sealing property, then the fit strength and sealing property are improved, but the internal pressure in the bearing space becomes significantly high
Solution Approach 1:
The protective cap is divided into a cylindrical part and a lid part that can be assembled separately. The cylindrical part is press-fitted into the outer race member first, establishing the fit strength, while the lid part is attached later to complete the sealing without requiring high press-fit force that would generate excessive internal pressure
Solution Approach 2:
A seal ring is introduced as an intermediary component between the protective cap and the outer race member. This seal ring maintains the sealing property while allowing the cap to be attached with lower press-fit force, thereby reducing the internal pressure generated during assembly
2Strength
If the protective cap is press-fitted into the outer race member, then the fit strength is improved, but the rotary torque of the inner race member increases
Solution Approach 1:
The protective cap is divided into a cylindrical part and a lid part. The cylindrical part is press-fitted to provide fit strength, while the lid part is attached separately with minimal force, avoiding the generation of excessive internal pressure that would increase rotary torque
Solution Approach 2:
The cylindrical part is press-fitted into the outer race member as a preliminary step to establish fit strength. The lid part is then attached with minimal force, preventing excessive internal pressure buildup that would otherwise increase the rotary torque of the inner race member
3Reliability
If the protective cap is attached under high internal pressure, then the sealing property is improved, but the protective cap becomes obliquely attached
Solution Approach 1:
The protective cap is segmented into a cylindrical part and a lid part. The cylindrical part is press-fitted first with controlled force to establish sealing without excessive internal pressure, and the lid part is attached later in a separate step, ensuring proper alignment and preventing oblique attachment
Solution Approach 2:
The cylindrical part is press-fitted into the outer race member as a preliminary step with controlled force to establish the sealing interface. The lid part is then attached in a subsequent step with minimal force, preventing excessive internal pressure that would cause oblique attachment and ensuring accurate positioning
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
The solution effectively suppresses internal pressure increases, maintains accurate ABS detection, reduces rotary torque, and ensures long-term sealing integrity, thereby enhancing the operational efficiency and reliability of the hub bearing.
Implementation Method 1
In the course of fitting the cylindrical part to the outer race member, the ventilation part allows air to pass between inside and outside of a bearing space
Implementation Method 2
an annular seal part configured to, when being fitted to the outer race member, intervene in a compressed state between the cap for the bearing device and the outer race member
Data Source
AI summary
A cap for bearing device is attached to one end portion of an outer race member in a bearing device to block an opening portion, and includes: a cylindrical part that is fitted to the outer race member; a lid part configured to block an end portion of the cylindrical part; an annular seal part configured to, when being fitted to the outer race member, be compressed between the cap for the bearing device and the outer race member; and a ventilation part, which, in the course of fitting the cylindrical part to the outer race member, allows air to pass between inside and outside of a bearing space, and in the state where the cylindrical part is fitted to the outer race member, the ventilation is shut down.