Hollow Rack Bar Tooth Forming with Stepwise Mandrel Sizing
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Solution Overview
Problem
Existing methods for manufacturing hollow rack bars require multiple mandrel insertions to achieve desired tooth width, leading to increased manufacturing costs and reduced lifetime of the teeth forming die.
Innovation Solution
The method involves using mandrels with progressively larger heights and stepwise reduction in the width of the pressing portion to form teeth on a hollow shaft member, allowing for easier enlargement of tooth width with fewer mandrel insertions and extending the life of the forming die.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the number of mandrel insertions is increased to achieve wider tooth width, then the tooth width becomes wider, but the lifetime of the teeth forming die is shortened and manufacturing cost increases
Solution Approach 1:
The mandrel pressing portion width is dynamically adjusted across different insertion stages. Earlier insertions use mandrels with larger pressing portion widths to efficiently expand tooth width, while later insertions use mandrels with smaller pressing portion widths to minimize die load and preserve die lifetime, creating a dynamic adaptation strategy that balances productivity and equipment durability
Solution Approach 2:
The pressing portion width parameter of the mandrel is changed systematically across insertion sequences. By varying this critical parameter - larger widths initially for rapid expansion, smaller widths subsequently for precision and die protection - the process optimizes both tooth width achievement and teeth forming die preservation without requiring increased insertion frequency
2Area of moving object
If the number of mandrel insertions is increased to achieve wider tooth width, then the tooth width becomes wider, but the manufacturing cost increases
Solution Approach 1:
The mandrel pressing portion width is dynamically adjusted across different insertion stages. Earlier insertions use mandrels with larger pressing portion widths to efficiently expand tooth width, while later insertions use mandrels with smaller pressing portion widths to minimize die load and preserve die lifetime, creating a dynamic adaptation strategy that balances productivity and equipment durability
Solution Approach 2:
The pressing portion width parameter of the mandrel is changed systematically across insertion sequences. By varying this critical parameter - larger widths initially for rapid expansion, smaller widths subsequently for precision and die protection - the process optimizes both tooth width achievement and teeth forming die preservation without requiring increased insertion frequency
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 effectively enlarges tooth width with fewer mandrel insertions, reducing manufacturing costs and prolonging the life of the teeth forming die while maintaining precision in tooth formation.
Implementation Method 1
the material of the teeth base portion is plastically worked by the mandrels and enters the grooves of the teeth forming die
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A rack bar (14) is manufactured by sequentially inserting a plurality of mandrels into a hollow shaft member with a teeth forming die being pressed against an external surface of a teeth base portion of the shaft member, such that the size of the mandrel in the height direction is increased in a stepwise manner and such that the size of the pressing portion of the mandrel in the width direction is reduced in a stepwise manner. The manufactured rack bar (14) has a first worked surface (15) and a second worked surface (16), both formed on an internal surface of the teeth base portion in a recessed manner and extending in the axial direction. The second worked surface is formed at a central portion of the first worked surface with respect to a tooth-width direction.