Motion Guide Device Ball Collision Damage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motion guide devices suffer from damage to the scooping portion due to concentrated stress from continuously colliding balls, especially when the moving block operates at high speeds, as the tapered shape of the scooping portion leads to fatigue and potential damage.
Innovation Solution
A motion guide device design that eliminates the need for a tapered scooping portion by using a first contact surface adjacent to the ball rolling surface and a second contact surface across it, guiding balls through the direction changing path without scooping, allowing the contact surface to be thicker and reducing stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the scooping portion is formed with a tapered shape to guide balls into the direction changing path, then the balls can be effectively scooped from the ball rolling surface, but the contact area with the ball is small leading to increased contact pressure and damage to the scooping portion
Solution Approach 1:
The invention changes the geometric parameters of the scooping portion by replacing the tapered shape with a substantially U-shaped cross-section. This parameter change increases the contact area with the ball, thereby reducing contact pressure and preventing damage to the scooping portion while maintaining the ball guiding function
Solution Approach 2:
The invention applies curvature by forming the scooping portion with a U-shaped cross-section that has curved surfaces conforming to the spherical shape of the balls. The curved surface of the scooping portion matches the spherical shape of the balls, increasing contact area and reducing stress concentration compared to the tapered shape
2Strength
If the leading end of the scooping portion is formed into a planar shape to increase contact area with the ball, then contact pressure is reduced, but the taper shape remains and stress concentration still occurs leading to fatigue damage
Solution Approach 1:
The invention replaces the planar leading end with a curved surface that conforms to the spherical shape of the balls. This curvature ensures uniform stress distribution across the contact area, preventing stress concentration and fatigue damage while maintaining large contact area
Solution Approach 2:
The invention changes the geometric parameters by eliminating the taper shape entirely and adopting a U-shaped cross-section with uniform thickness. This parameter change distributes stress evenly across the scooping portion, preventing fatigue damage while maintaining adequate contact area
3Ease of operation
If the scooping portion is arranged at the wedge-shaped space between the ball spherical surface and the ball rolling surface to scoop the balls, then the ball guiding function is achieved, but the scooping portion is subjected to concentrated stress from continuously colliding balls
Solution Approach 1:
The invention uses a curved surface in the scooping portion that matches the spherical shape of the balls, allowing smooth ball separation from the load ball path without concentrated stress. The curved surface enables balls to transition smoothly into the direction changing path, achieving ball separation function while distributing stress evenly
Solution Approach 2:
The invention changes the geometric parameters by replacing the wedge-shaped arrangement with a U-shaped cross-section having uniform thickness. This parameter change eliminates stress concentration while maintaining the ball separation function through the curved surface configuration
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
Prevents damage to the lid member from ball collisions and enables high-speed operation of the moving block by distributing the contact pressure more evenly, ensuring the lid member remains intact and functional.
Implementation Method 1
a track member having a ball rolling surface extending in a longitudinal direction thereof; a moving member main body having a load ball rolling surface that is opposed to the ball rolling surface to form a load ball path
Implementation Method 2
a first contact surface that is provided adjacent to one side portion of the ball rolling surface and is continuous with the direction changing path so as to intersect with the load ball path, the first contact surface guiding the plurality of balls rolling on the ball rolling surface to another side portion of the ball rolling surface
Data Source
AI summary
Provided is a motion guide device capable of preventing a lid member from being damaged due to collision of balls and operating a moving block on a track rail at high speed. The motion guide device includes: a track member having a ball rolling surface; a moving member main body having a load ball rolling surface that forms a load ball path between the load ball rolling surface and the ball rolling surface, and a ball return path provided in parallel to the load ball path); a lid member having a direction changing path that connects the load ball path and the ball return path to each other to form an endless circulation path; and balls arranged in the endless circulation path. The lid member includes an introducing portion of the direction changing path, which includes a first contact surface continuous with the direction changing path.