Asymmetric Rack-and-Pinion Linear Motion Guide
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Solution Overview
Problem
Current finite linear motion guide units face challenges in miniaturization, high-speed acceleration/deceleration, and assembly ease, particularly with deeper raceway grooves that can lead to incorrect assembly of the rack within the guideway members.
Innovation Solution
A miniaturized linear motion guide unit with a rack-and-pinion mechanism featuring asymmetrical connecting bars and grooves, a retainer plate with tilted windows, and a pinion wheel integrated with the holder, made of thermoplastic resin, to prevent discrepancies and simplify assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deeper raceway grooves are used in guideway members, then the rack can be retained more securely, but the rack becomes easier to assemble incorrectly in the wrong orientation
Solution Approach 1:
The patent applies asymmetry by making the connecting bars of the rack different in width (first connecting bar wider than second connecting bar) and the grooves in the guideway members different in shape (first groove wider than second groove). This asymmetric design ensures that the rack can only be assembled in the correct orientation, preventing incorrect assembly while maintaining secure retention through the deeper grooves.
2Volume of moving object
If the linear motion guide unit is miniaturized, then it becomes more compact and suitable for small-sized applications, but the number of discrete components increases making assembly more difficult
Solution Approach 1:
The patent merges the holder and retainer plate into a single integrated component. The holder has a retainer plate portion and a pinion holder portion formed as one piece, eliminating the need for separate holder and retainer plate components. This reduces assembly complexity while maintaining the miniaturized size of the guide unit.
3Force
If more rollers are placed in a predetermined length to increase load capacity, then the holder plate must be made more rigid to prevent warping, but this increases the complexity of the holder structure
Solution Approach 1:
The holder and retainer plate are integrated into a single component, which simplifies the overall structure while providing the necessary rigidity to support multiple rollers. The integrated design eliminates the need for separate reinforcement structures that would otherwise be required to prevent warping of a rigid holder plate with multiple rollers.
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 ensures accurate and easy assembly of the rack within the guideway members, supports high-speed and high-loaded conditions, and reduces production costs through a simpler, compact design with fewer components.
Implementation Method 1
more than one rolling element of cylindrical roller lying between the guideway members
Implementation Method 2
a pinion wheel supported for rotation in a hole made in the retainer plate
Data Source
AI summary
A small-sized finite linear motion guide unit is provided in which there is provided a rack-and-pinion arrangement to prevent any discrepancy between retainer plates to make sure of relative sliding movement of guideways. A rack is composed of teeth portions and a pair of connecting bars to fasten the teeth thereon. The connecting bars are different in widthwise length to form asymmetrical shapes. The grooves for a rack made on the guideway includes a middle groove to get the rack to mate with the pinion, and sidewise grooves lying on both sides of the middle groove and having the connecting bars different in widthwise length to make an asymmetric shape.