Linear Ball Guide Cage With Elongated Slots for Oscillation Wear
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Solution Overview
Problem
Conventional medical devices with linear ball bearings face issues with wear and reduced service life due to mass inertia causing balls to slip or slide at reversal points during high-frequency oscillating movements, leading to undesired wear and reduced guidance quality.
Innovation Solution
The design features elongated ball receptacles with a longitudinal axis transverse to the machine element's axis, allowing balls to move freely and roll on both partners, minimizing bearing cage movement and wear, while enabling easier cleaning and using conventional steel bearing cages without the need for mass reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional linear guides with balls embedded in bores of a bearing cage are used, then the structure is simple and easy to manufacture, but the balls slip or slide at reversal points during high-frequency oscillating movements causing wear and reduced service life
Solution Approach 1:
The bearing cage is segmented into multiple slots, each containing a ball. The slots are designed with specific orientations (some perpendicular, some at angles between 0-90 degrees to the longitudinal axis) to allow balls to move independently in different directions, preventing simultaneous sliding of all balls at reversal points and reducing wear
Solution Approach 2:
The ball receptacles are designed to allow dynamic movement of balls within the slots. During high-frequency oscillating movements, balls can move freely within their slots to adapt to the motion, preventing the bearing cage itself from moving significantly while allowing individual balls to maintain contact with the machine element
2Weight of moving object
If the bearing cage is made from lighter materials such as plastic or ceramic to reduce mass, then the oscillating movement is improved, but plastics suffer from high wear and ceramics are expensive and complex to manufacture
Solution Approach 1:
The design changes the operational parameters by allowing the bearing cage to remain essentially stationary while balls move independently within slots. This eliminates the need to reduce the bearing cage mass, enabling the use of conventional steel bearing cages that are easy to manufacture and maintain high wear resistance
3Ease of manufacture
If conventional linear guides are used, then the structure is compact, but cleaning fluid cannot penetrate effectively between the balls and the ball receptacles
Solution Approach 1:
The bearing cage is divided into multiple discrete slots that create channels for cleaning fluid flow. The spaced arrangement of slots and balls allows cleaning fluid to penetrate effectively between the balls and the bearing cage structure, improving cleanability while maintaining a compact overall structure
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 design minimizes wear and tear, extends the service life of the medical device, and improves cleanability by decoupling ball movement from the bearing cage, allowing for high-frequency oscillations without significant bearing cage movement and reducing the risk of sliding over the machine element.
Implementation Method 1
the balls in the elongated ball receptacles can move back and forth and thus roll on one or both sliding partners, for example, the guided machine element
Implementation Method 2
Due to inertia, at the reversal point of the oscillation, the balls can slip or slide on their respective running surfaces
Implementation Method 3
the plurality of ball receptacles are designed in the form of elongated holes, wherein the plurality of elongated holes have a free movement length for the ball movably arranged in them
Data Source
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AI summary
The invention relates to a medical device (10) with a machine element (20) mounted in a linearly movable manner and at least one linear guide (38) defining a longitudinal axis (34) and comprising a ball bearing (40), which is used to guide a linear movement of the machine element parallel to the longitudinal axis, said at least one ball bearing comprising a plurality of balls (42) which are held in a movable manner in corresponding ball receiving elements (44) and guide the machine element. The aim of the invention is to improve the guiding of the machine element. To this end, the plurality of ball receiving elements is designed in the form of long holes (48).