Ball Screw Nut Lubrication via Capillary Felt Plug
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Solution Overview
Problem
Conventional ball screw dust-proof and lubricating devices fail to effectively lubricate when in a vertical position, require frequent replacement of oil-absorbing materials, and often increase the axial length or reduce travel length of the nut.
Innovation Solution
A ball screw design incorporating an oil-absorbing member within the nut, a return unit for ball circulation, and dust-proof members at both ends, which allows for lubrication in any position without the need for oil replacement and maintains the nut's axial length and travel length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radial oil-feeding holes are used to feed lubricant into the helical groove, then lubrication can be provided in horizontal position, but lubrication fails when the ball screw is disposed in a vertical position due to gravity
Solution Approach 1:
An oil-absorbing member (felt plug) is introduced as an intermediary between the oil-feeding hole and the helical groove. This felt plug absorbs lubricant oil and releases it gradually through capillary action, mediating the lubrication process to work effectively in both horizontal and vertical positions regardless of gravity's direction
Solution Approach 2:
The oil-absorbing member is made of porous felt material that can absorb and retain lubricant oil. The porous structure allows the felt to hold oil through absorption and then release it through capillary action to the helical groove, ensuring lubrication works in any orientation
2Reliability
If solid lubricant is used at both ends of the nut, then automatic lubrication is achieved, but the solid lubricant needs to be replaced when used up which is inconvenient
Solution Approach 1:
The oil-absorbing member (felt plug) is designed to be reusable and self-regenerating. After use, it can be cleaned and reused, eliminating the need for frequent replacement. The system provides automatic lubrication while being easy to maintain through simple cleaning operations
Solution Approach 2:
Instead of discarding the oil-absorbing member after one use, the invention allows for recovery and reuse of the felt plug by cleaning it to remove accumulated debris and old lubricant, then reusing it for subsequent lubrication cycles
3Reliability
If an oil-storage device is disposed at one end of the nut to store lubricant oil, then continuous lubrication can be provided, but the axial length of the nut increases and the travel length is reduced
Solution Approach 1:
The oil-guiding hole serves multiple functions: it acts as both a passage for lubricant oil and a storage space for lubricant oil through the oil-absorbing member. This multi-functionality eliminates the need for a separate dedicated oil storage chamber, avoiding additional axial length
Solution Approach 2:
The lubricant storage function is merged with the existing oil-guiding hole structure. The oil-absorbing member placed within the oil-guiding hole creates an integrated lubricant reservoir that utilizes the existing space rather than adding a separate storage component
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
Ensures continuous lubrication of the ball screw in both horizontal and vertical positions without the need for oil replacement, maintaining the nut's dimensions and ensuring effective dust prevention.
Implementation Method 1
an oil-absorbing member (50) made of felt or the like and having one end disposed in the oil-guiding hole (34) and the other end disposed in the radial oil holes (35, 36)
Data Source
AI summary
A ball screw with a dust-proof and lubricating device comprises: a screw, a nut, a plurality of balls, an oil-absorbing member, a return unit, and two dust-proof members. The nut includes an axial oil-guiding hole, a plurality of radial oil holes in communication with the oil-guiding hole and the helical groove of the nut, and an oil-feeding hole in communication with one of the radial oil holes. The oil-absorbing member is disposed in the oil-guiding hole and the radial oil holes. The return unit is disposed in the nut to enable the turning and circulation of the balls. The two dust-proof members are located at both ends of the axial hole. The ball screw can still be lubricated when it is disposed in a vertical position, and the dust-proof and lubricating device which won't add axial length to the nut.