Electric Power Steering Bus Bar with Plated and Cut Surfaces
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Solution Overview
Problem
The existing electric power steering controllers require time and effort to manufacture due to the need for multiple types of bus bars and complex assembly processes, which also limits their size reduction in narrow vehicle spaces.
Innovation Solution
A bus bar configuration with a plating layer on one surface and a cutting plane on the other allows for both wire bonding and resistance welding, simplifying the manufacturing process and reducing size by eliminating the need for masking materials and optimizing terminal placement parallel to the circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple types of bus bars are used for different joining methods, then joining versatility is improved, but manufacturing complexity and time increase
Solution Approach 1:
The bus bar is designed with different surface characteristics at different locations: one surface has a plating layer suitable for wire bonding, while another surface has a cutting plane exposing the metal plate for resistance welding. This local differentiation allows a single bus bar component to support multiple joining methods without increasing overall complexity
Solution Approach 2:
The bus bar is designed as a universal component that can accommodate both wire bonding and resistance welding joining methods through its multi-functional surface design, eliminating the need for separate specialized bus bars for each joining method
2Manufacturing precision
If masking material is used during plating to expose specific portions, then plating precision is improved, but manufacturing time and effort increase
Solution Approach 1:
The plating layer is applied to the entire outer surface of the bus bar in advance, before any cutting operations. This preliminary plating eliminates the need for masking during the plating process, as the full surface is plated uniformly and subsequently cut to the required shape
Solution Approach 2:
Instead of the conventional approach of masking specific areas during plating to expose portions, the invention inverts the sequence by plating the entire surface first and then cutting away unnecessary portions, achieving the same result without masking steps
3Ease of manufacture
If the terminal is arranged perpendicular to the circuit board, then electrical connection is simplified, but controller size increases
Solution Approach 1:
The terminal is repositioned from a perpendicular arrangement (one dimension) to a parallel arrangement relative to the circuit board (changing the spatial dimension). This dimensional change allows the terminal to be positioned in a space that reduces the overall controller footprint while maintaining effective electrical connection capability
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 manufacturing time and cost while enabling a more compact controller design, enhancing the flexibility of electric power steering systems in narrow vehicle spaces.
Implementation Method 1
a joining method suitable for joining to a plating layer, such as wire bonding, may be applied to joining a component to the plating layer
Implementation Method 2
a joining method suitable for joining to metal, such as resistance welding, may be applied to joining a component to the cutting plane
Data Source
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AI summary
An ECU includes a power board (49), a first bus bar (78) and a second bus bar (79). The first bus bar (78) and the second bus bar (79) are retained by a retaining member (76) made of synthetic resin. The bus bars (78, 79) each are formed in such a manner that a metal plate of which an outer surface plated with a nickel plating layer (78a, 79a) is cut along a predetermined cutting plane (78c, 79c). Sixth portions (96a, 96b, 106a, 106b) of the respective bus bars (78, 79), are exposed from the retaining member (76). The cutting planes (78c, 79c) at the respective sixth portions (96a, 96b, 106a, 106b) are parallel to a principal surface (49a) of the power board (49), and are joined to terminals (81b, 82b, 81c, 82c) of respective capacitors (81, 82) by resistance welding. Bonding wires (99, 110) are respectively joined to the nickel plating layers (78a, 79a) of the bus bars (78, 79).