Engine Rear Seal Lip Dynamics for Mud Water Sealing
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Solution Overview
Problem
Existing engine rear seals fail to effectively prevent muddy water from entering the engine oil in the rear end portion of a crankshaft, leading to compromised sealing performance and increased rotary torque.
Innovation Solution
An engine rear seal with a contact-type muddy water preventing seal, featuring an inclined scraper-shaped seal lip that contacts the end plate at low speeds and moves away due to centrifugal force at high speeds, combined with an oil seal and a narrow axial gap between the seal and flywheel, to enhance sealing performance and reduce sliding torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-contact type dust seal is provided in the motor exterior side of the oil seal, then the sealing performance is improved, but muddy water enters through the gap portion of the non-contact type seal
Solution Approach 1:
The sealing system is divided into multiple functional segments: the oil seal for primary sealing, the non-contact type dust seal for dust protection, and the newly added contact-type muddy water preventing seal specifically for muddy water barrier. This segmentation allows each component to address specific contamination types without compromising overall sealing performance.
Solution Approach 2:
The contact-type muddy water preventing seal acts as an intermediary barrier between the muddy water environment and the internal sealing components. It specifically targets muddy water particles before they can reach the oil seal and non-contact dust seal, protecting these components from muddy water damage while maintaining their original sealing functions.
2Object-affected harmful factors
If a contact type seal is used to prevent muddy water entry, then muddy water sealing performance is improved, but rotary torque increases due to friction
Solution Approach 1:
The contact-type muddy water preventing seal is designed with localized sealing properties only where necessary for muddy water protection. The seal lip contacts the end plate surface at specific points to create an effective barrier against muddy water, while the contact area is minimized to reduce frictional resistance and rotary torque.
Solution Approach 2:
The seal lip of the contact-type muddy water preventing seal is designed with dynamic characteristics that allow it to adapt to operating conditions. The flexibility and material properties enable the seal to maintain effective contact for muddy water prevention while accommodating shaft rotation with minimal friction, thus reducing rotary torque increase.
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 significantly improves muddy water sealing performance while minimizing the increase in sliding torque, ensuring effective sealing even at low speeds and reducing wear, thus extending the seal's lifespan.
Implementation Method 1
the lip end moves away from the end surface in the motor exterior side of the end plate on the basis of an action of a centrifugal force when the shaft rotates at a high speed
Data Source
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AI summary
Provided is an engine rear seal that can further improve mud water seal properties and that can inhibit an increase in rotation torque. To achieve this objective, there is provided an engine rear seal mounted on an engine rear section in which an end plate is arranged on the machine exterior side of a housing and a flywheel is connected to a shaft arranged on the machine exterior side of the end plate, the engine rear seal comprising: an oil seal, and a mud water prevention seal arranged on the machine exterior side of the oil seal. The mud water prevention seal integrally has an attachment section, and a seal lip provided in the exterior radial direction from the attachment section and used for making close sliding contact with the edge surface of the machine exterior side of the end plate. The seal lip has a sloped lip edge back surface section, and has a structure in which the lip edge is in contact with the end plate during low speed rotation and is set at a distance from the end plate by the effect of centrifugal force during high speed rotation.