Electric Power Steering Driving Unit Protrusion Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric power steering systems face issues with water and foreign matter entering the motor case through worn boots, leading to mechanical locking or electrical shorts due to rust, which can cause the system to malfunction.
Innovation Solution
A driving unit with a stator, rotor, shaft, housing, protrusion, and sealing member is designed, where the protrusion has a hole for the shaft and a sealing member that prevents water from entering by allowing it to drip down the housing's outer surface, reducing wear on the sealing member and preventing water entry into the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If boots are used to seal the rack housing, then water entry is prevented initially, but the boots wear out due to impact by foreign matter and aged deterioration, allowing impure water to enter
Solution Approach 1:
The patent extracts the sealing function from the boots and relocates it to the protrusion structure. The protrusion extends from the housing outer surface to form a sealed barrier, separating the sealing function from the boot components. This allows the sealing capability to be maintained independently of boot deterioration.
Solution Approach 2:
The protrusion acts as an intermediary element between the housing and the external environment. It creates an intermediate sealed space that prevents direct contact between impure water and the internal components, mediating the protection against water entry even when boots are worn.
2Reliability
If impure water enters the motor case through worn boots, then mechanical locking or electrical short occurs due to rust, but adding more sealing components increases device complexity
Solution Approach 1:
The patent merges the sealing function with the existing protrusion structure (such as a mounting flange or structural protrusion). By integrating the sealing capability into an existing structural element rather than adding a separate sealing component, the protection against water entry is achieved without increasing device complexity.
Solution Approach 2:
The protrusion serves multiple functions: it provides structural support or mounting functionality while simultaneously creating a sealed barrier against water entry. This multi-functionality eliminates the need for additional dedicated sealing components, maintaining simplicity while enhancing protection.
3Reliability
If a sealing member is placed in the hole of the protrusion, then water entry is blocked, but the sealing member wears due to contact with impure water containing foreign matter
Solution Approach 1:
The protrusion structure is designed to intercept and redirect impure water flow before it reaches the sealing member. By creating a sealed barrier at the protrusion outer surface, the system performs preliminary protection, preventing contaminated water from contacting and wearing the sealing member.
Solution Approach 2:
The patent converts the potential harmful effect of impure water contact into a beneficial flow pattern. The protrusion structure guides water flow along its outer surface in a controlled manner, causing water to drip down away from the sealing member rather than directly contacting it, thus transforming the water flow from a harmful force into a controlled pathway that protects the sealing member.
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 prevents water and foreign matter from entering the housing, reducing the risk of mechanical locking and electrical shorts, ensuring the electric power steering system operates reliably.
Implementation Method 1
the impure water drops along the outer circumferential surface of the protrusion, when the impure water is brought into contact with the outer surface positioned at one side of the housing in an axial direction of the rotor, and then the impure water goes down under gravity along the outer surface of the housing
Data Source
AI summary
A driving unit includes a stator, a rotor, a shaft, a housing, a protrusion, a small pulley, and a sealing member. The rotor is rotatably disposed relative to the stator. The shaft rotates together with the rotor. The housing houses the stator and the rotor. The protrusion protrudes from an outer surface of the housing toward an outside of the housing. The outer surface is positioned at one side of the housing in an axial direction of the rotor. The small pulley is disposed at an end of the shaft protruding toward the outside of the housing through a hole formed in the protrusion. The small pulley is cylindrical shaped. The sealing member seals a space between an inner surface of the hole of the protrusion and an outer surface of the shaft.