Motor Housing-Bracket Caulking for Stronger EPS Assembly
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Solution Overview
Problem
The connection between the housing and bracket in electric power steering system motors is prone to reduced fastening force, leading to noise, vibration, and durability issues due to the use of bolts or rivets, which can result in a weak joining state.
Innovation Solution
A motor assembly method involving the formation of coupling holes in one component and plastic parts in the other, followed by caulking to secure the housing and bracket, eliminating the need for separate fastening means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fastening members such as bolts or rivets are used to connect the housing and bracket, then the connection can be assembled, but the fastening force is reduced and the connection cannot be maintained in a firm state
Solution Approach 1:
The connection structure is divided into multiple coupling holes distributed around the support hole, with each hole providing independent fastening. This segmentation allows the total fastening force to be distributed across multiple points, preventing localized failure and maintaining overall connection stability.
Solution Approach 2:
The plastic part is inserted into the coupling hole formed in the housing, creating a nested structure where the plastic fastening element is housed within the metal component. This nesting provides both structural support and secure fastening through the interference fit and deformation mechanism.
2Ease of manufacture
If fastening members such as bolts or rivets are used to connect the housing and bracket, then the connection can be assembled, but noise and vibration occur during operation
Solution Approach 1:
The connection method transitions from mechanical fastening with clearance (bolts/rivets) to interference fit with plastic deformation. The plastic part is deformed to expand and lock within the coupling hole, creating a rigid connection that eliminates operational clearance and prevents vibration-induced noise.
Solution Approach 2:
The connection utilizes composite construction combining the metal housing with a plastic fastening element. The plastic material provides damping properties that reduce vibration and noise while maintaining the structural integrity of the metal components.
3Ease of manufacture
If fastening members such as bolts or rivets are used to connect the housing and bracket, then the connection can be assembled, but durability is significantly deteriorated
Solution Approach 1:
The coupling holes are pre-formed in the housing with precise dimensions and surface treatments before assembly. This preliminary preparation ensures proper fit and deformation characteristics, enabling reliable permanent fastening that maintains durability throughout the product lifecycle.
Solution Approach 2:
The plastic part deforms under pressing force to expand and lock itself within the coupling hole, creating a self-securing connection. This self-service mechanism eliminates the need for additional fastening operations and ensures consistent durability through the material's own deformation properties.
4Strength
If separate fastening means are used to connect the housing and bracket, then the connection can be secured, but the number of parts increases and productivity decreases
Solution Approach 1:
The fastening function is merged into the bracket structure itself through the integrated plastic part. This eliminates the need for separate fastening components and reduces the total part count, while maintaining strong joining strength through the deformation-based locking mechanism.
Solution Approach 2:
The plastic part performs multiple functions: structural support, vibration damping, and permanent fastening. This self-service capability eliminates the need for separate fastening operations, reducing assembly steps and improving productivity while maintaining connection strength.
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 approach enhances the joining strength, reduces defect rates, and increases productivity by maintaining a robust connection without additional parts.
Implementation Method 1
pressing the at least one plastic deformable part of the bracket toward the housing with a pressurizer such that the at least one plastic deformable part is deformed to form a protrusion inserted into the at least one coupling hole of the housing and a catch projection expanded from the protrusion and supported on an inner surface of the housing
Data Source
AI summary
In a motor and a method of assembling a motor, a coupling hole is formed in one of a housing and a fixing bracket and a plastic deformation part is formed in the other, and then stacked and fixed by caulking, so that the joining is maintained in a firm state and the defect rate can be drastically reduced, and the number of parts can be reduced and productivity can be increased without a separate fastening means.