Disc Drive Suspension Flexure with Trapezoidal Conductors
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Solution Overview
Problem
Conventional suspension systems for disc drives face limitations in bending stiffness and electrical conductivity, with existing conductors exhibiting low peel strength and high bending stiffness, which can affect signal transfer and slider attitude.
Innovation Solution
A suspension system with a flexure featuring a metal base member, a circuit member with a trapezoidal cross-section conductors formed by etching deposited copper on a resin base member, and spring portions that reduce bending stiffness while enhancing peel strength and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conductors with rectangular cross-section are used in conventional flexures, then the manufacturing process is simple, but the peel strength against bending is limited
Solution Approach 1:
The conductor cross-section is designed as a trapezoid rather than a rectangle, with the wider base facing the resin base member. This asymmetric geometry increases the contact area between the conductor and resin base member, thereby enhancing peel strength and resistance to bending forces while maintaining manufacturing feasibility through standard etching processes
2Reliability
If rolled copper is used for conductors, then the bending stiffness is higher, but the electrical conductivity is lower and it cannot handle high-speed signal transfer
Solution Approach 1:
The patent specifies using deposited copper instead of rolled copper, changing the material parameter to achieve higher electrical conductivity suitable for high-speed signal transfer. The trapezoidal cross-section geometry is also optimized to provide appropriate bending stiffness characteristics while maintaining the superior electrical properties of deposited copper
3Stability of the object's composition
If the circuit member is made with higher bending stiffness, then the structural stability is improved, but the spring characteristics adversely affect the roll or pitch static attitude of the slider
Solution Approach 1:
The flexure structure is designed with spatial variation in stiffness characteristics. The circuit member and resin base member are configured to provide appropriate local stiffness properties that maintain structural stability while allowing necessary flexibility for slider positioning. The trapezoidal conductor geometry contributes to optimized local mechanical properties in the circuit member regions
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 achieves a balance of low bending stiffness and high electrical conductivity, improving signal transfer and maintaining accurate slider orientation by reducing the influence on pitch and roll stiffness.
Implementation Method 1
conductors of predetermined circuit patterns formed by etching a deposited copper layer deposited on the resin base member
Implementation Method 2
A bending stress may act in the thickness direction in some flexures with a circuit member
Data Source
AI summary
A suspension for disc drive includes a base plate, a load beam, and a flexure. The flexure includes a metal base member and a circuit member disposed along the metal base member. The circuit member extends in a longitudinal direction of the load beam. The circuit member includes a resin base member formed of an electrically insulating resin and conductors. The conductors are formed into predetermined circuit patterns by etching a deposited copper layer deposited on the resin base member. Each conductor has a cross section in the shape of a trapezoid such that the width of a surface of the conductor which faces the resin base member is greater than that of a surface of the conductor on the side opposite from the resin base member.