Rolling-Element Mold Guiding and Centering for Low-Wear Alignment
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Solution Overview
Problem
Existing guiding and centering devices for mold halves in forming tools suffer from unbalanced friction, jittering, and high wear, leading to reduced workpiece quality and shortened service life, and require additional lubrication and fine centering units.
Innovation Solution
A guiding and centering device with a protruding guide body and guide recess featuring a rolling element cage and preload mechanism, utilizing a spring element and axial retainer to ensure precise alignment and low wear, eliminating the need for separate fine centering devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sliding bush and guide column are used for guiding mold halves, then the structure is simple and easy to manufacture, but unbalanced friction causes jittering and reduces workpiece quality
Solution Approach 1:
A polymeric insert is introduced as an intermediary component between the guide column and guide bush. This insert features a hardened outer surface for precise guiding and a softer inner surface that reduces friction and prevents jittering, thereby maintaining manufacturing simplicity while improving workpiece quality
Solution Approach 2:
The guide bush is constructed as a composite structure with a metallic base material and a polymeric insert. This composite design combines the structural strength of metal with the low-friction properties of polymer, eliminating jittering while maintaining the simple sliding bush structure
2Device complexity
If sliding bush and guide column are used for guiding mold halves, then the structure is simple, but high friction leads to increased wear and shortened service life
Solution Approach 1:
The polymeric insert acts as a mediator between the guide column and guide bush, providing a low-friction interface that significantly reduces wear on both components, thereby extending service life while maintaining the simple overall device structure
Solution Approach 2:
The polymeric insert is designed as a replaceable component that can be easily replaced when worn. This allows the expensive metallic guide column and bush to be preserved, extending their service life while using a lower-cost, easily replaceable insert
3Device complexity
If sliding bush and guide column are used for guiding mold halves, then no additional components are needed, but lubrication is required to reduce friction
Solution Approach 1:
The polymeric insert material itself provides self-lubricating properties through its inherent low-friction surface characteristics, eliminating the need for external lubrication systems while maintaining simple device structure
Solution Approach 2:
The friction characteristics of the guiding interface are changed by selecting polymeric materials with inherently low coefficients of friction. This material parameter change eliminates the need for lubrication while maintaining the simple sliding bush structure
4Manufacturing precision
If separate positioning device is added to ensure precise alignment, then alignment accuracy is improved, but device complexity increases
Solution Approach 1:
The guiding and positioning functions are merged into a single integrated system. The polymeric insert within the guide bush simultaneously provides precise alignment through its hardened outer surface and positioning accuracy through its precise fit, eliminating the need for separate positioning devices
Solution Approach 2:
The guide bush with polymeric insert is designed to perform multiple functions: guiding the mold halves, ensuring precise alignment, and providing positioning accuracy. This multi-functional design eliminates the need for additional separate positioning devices, maintaining device simplicity
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
Provides play-free guidance with high repeatability and reduced wear, extending service life and allowing for low-lubrication operation, suitable for various molding tools with adaptable dimensions.
Implementation Method 1
a rolling element cage (16) with rolling elements (17) inserted in rows (18), by means of which the two mold halves are guided into and precisely centered in the closed position
Implementation Method 2
to reduce friction along the bearing surfaces when mating the members together
Implementation Method 3
a spring element and axial retainer to ensure precise alignment and low wear
Implementation Method 4
utilizing a spring element and axial retainer to ensure precise alignment
Data Source
Figure 1~2
Figure 3
Figure 4a~4b
AI summary
The present invention relates to a guiding and centering device (10) for a forming tool (2), in particular an injection molding or die-casting tool, comprising a first mold half (1) and a second mold half (5) which are guided by guide means (7) from a closed position in which the respective separating surfaces of both mold halves (1; 5) are pressed against one another into an opened position and vice versa. This guiding and centering device (10) comprises a protruding guiding body (4) formed as a circular cylindrical bolt (12) provided at the first mold half (1), a guiding recess (6) formed as a bush (14) with an circular cylindrical inner surface (20) provided at the second mold half (5) and a rolling element cage (16) with rolling elements (17) inserted in rows (18), by means of which the two mold halves (1; 5) are guided and precisely centered in the closed position. The rolling element cage (16) is supported by the circular cylindrical inner surface (20) of the bush (14) and positioned via positioning means (30) in such a way that when closing the forming tool the circular cylindrical bolt (12) runs practically simultaneously in a first row of rolling elements (18.1) and a second row of rolling elements (18.2) of the rolling element cage (16).