V-Type Retainer With Rack-Pinion Straying Prevention
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Solution Overview
Problem
Conventional finite linear motion guide units face challenges in preventing retainer straying or wandering, particularly in high-speed and high-acceleration applications, with existing mechanisms either complicating manufacture or not effectively increasing load capacity.
Innovation Solution
A finite linear motion guide unit incorporating a V-type retainer with a rack-and-pinion mechanism, where the retainer is formed with V-shaped concave and convex guide members and windows for needle rollers, and a cross-opening for the pinion, allowing for increased load capacity and precise positioning to prevent retainer straying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rack-and-pinion mechanism is added to prevent retainer straying, then positioning accuracy is improved, but device complexity increases
Solution Approach 1:
The retainer body is integrated with the pinion gear as a single molded unit, combining the retainer function and the straying prevention mechanism into one component. This reduces the number of separate parts while maintaining the rack-and-pinion positioning function, thus improving positioning accuracy without proportionally increasing device complexity.
Solution Approach 2:
The retainer body serves multiple functions simultaneously: it retains the needle rollers, prevents retainer straying through the integrated pinion-rack mechanism, and provides structural support. This multi-functionality reduces the need for additional separate components, addressing the positioning accuracy requirement without excessive complexity increase.
2Strength
If the number of needle rollers is increased to increase load capacity, then rated load is improved, but device complexity increases
Solution Approach 1:
The retainer body is divided into multiple window sections, each accommodating needle rollers. This segmented structure allows systematic arrangement of multiple rollers while maintaining organizational order and ease of assembly, enabling increased load capacity through multiple rollers without proportionally increasing complexity.
Solution Approach 2:
Multiple needle rollers are retained within a single integrated retainer body structure, combining multiple rolling elements into one unified component. This approach increases the rated load capacity through multiple rollers while avoiding the complexity of multiple separate retainer components.
3Strength
If a V-shaped retainer structure is used to increase load capacity, then rated load is improved, but manufacturing precision requirements increase
Solution Approach 1:
The retainer body is molded from synthetic resin material, utilizing polymer properties to achieve the required strength and load capacity. This material choice allows the V-shaped structure to bear loads while being manufacturable through molding processes, balancing manufacturing precision requirements with load capacity improvements.
Solution Approach 2:
The V-shaped geometry of the retainer body is optimized through parameter adjustment in the molding process, allowing the structure to achieve maximum load-bearing capability within the constraints of manufacturability. The specific angular and dimensional parameters are tuned to balance strength requirements with molding precision capabilities.
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 effectively supports high loads, increases the number of needle rollers, and prevents retainer straying, enabling smooth relative sliding motion and precise control, while reducing the weight and inertial forces of the guide members for improved performance.
Implementation Method 1
a rack-and-pinion mechanism serving as a retainer straying prevention mechanism... teeth of the pinion mesh with racks to form a retainer straying prevention mechanism
Implementation Method 2
a plurality of needle rollers disposed between the guide members and serving as rolling elements
Data Source
AI summary
In a finite linear motion guide unit, a retainer for retaining rollers rolling between guide members is formed into a V-like shape to thereby increase a rated load. A first guide member is formed into a V-like concave form, and a second guide member is formed into a V-like convex form. Needle rollers are retained by the V-shaped retainer and roll on a raceway formed by facing surfaces of the guide members. The V-shaped retainer includes a pair of roller retainer plate portions for retaining the needle rollers, and a retainer connection portion. A retainer straying prevention mechanism is composed of a pinion disposed in a cross-opening, and racks disposed on the guide members and meshing with the pinion.