Fluid Bearing Unit Torque Reduction via Low-Temperature Ester Lubricant
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fluid bearing units using monoester-based lubricants face challenges in reducing torque and maintaining fluidity at low temperatures, especially in extreme cold environments, limiting their operational range and efficiency in miniaturized and portable equipment.
Innovation Solution
The use of an ester derived from 1,5-pentanediol with a saturated monovalent fatty acid as a base oil, combined with a mixture of esters or polyolester/diester additives, enhances low-temperature fluidity and reduces torque, allowing the fluid bearing unit to operate effectively at temperatures below -40°C without significant increases in bearing torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If monoester-based lubricant is used to reduce bearing torque, then torque is reduced, but low-temperature fluidity is lost and the lubricant may solidify
Solution Approach 1:
The patent uses a composite lubricant formulation combining ester base oil with specific additives (polyolester and/or diester) to achieve both low torque and maintained fluidity at low temperatures. This composite approach allows the lubricant to exhibit desirable properties that neither component alone could provide.
Solution Approach 2:
The patent modifies the chemical composition parameters of the lubricant by specifying ester base oil with controlled viscosity (10-50 cSt at 40°C) and adding specific additives in controlled amounts (0.1-10 wt% polyolester and/or diester). These parameter changes enable the lubricant to maintain appropriate fluidity across a wide temperature range while keeping torque low.
2Force
If lubricant viscosity is reduced to lower bearing torque, then torque is reduced, but heat resistance is compromised
Solution Approach 1:
The patent employs a composite lubricant system where the ester base oil provides low viscosity for reduced torque, while the added polyolester and/or diester components contribute to thermal stability and heat resistance. This composite structure allows simultaneous optimization of both torque and temperature performance.
Solution Approach 2:
The patent carefully controls the viscosity parameter of the ester base oil (10-50 cSt at 40°C) to balance torque reduction with heat resistance. The addition of specific amounts of polyolester and/or diester (0.1-10 wt%) further adjusts the temperature-viscosity characteristics to maintain both low torque and adequate heat resistance.
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 configuration enables the fluid bearing unit to maintain low torque and operational reliability at extremely low temperatures, reducing motor current consumption and extending the operating temperature range of spindle motors.
Implementation Method 1
a lubricant in a gap between the shaft and the bearing is collected by dynamic pressure generating grooves formed in one of the shaft and the bearing, so that pressure is generated in the gap and the shaft is supported by the bearing in a non-contact manner
Implementation Method 2
an ester derived from 1,5-pentanediol having one alkyl side chain and saturated monovalent fatty acid having 5 to 8 carbon atoms... since an ester having low viscosity and excellent low temperature fluidity is used as the base oil of the lubricant
Data Source
AI summary
The present invention provides a fluid bearing unit capable of achieving lower torque and lower current consumption in comparison with a conventional bearing unit, and a spindle motor using the same. The present invention employs an ester derived from 1,5-pentanediol having one alkyl side chain and saturated monovalent fatty acid having 5 to 8 carbon atoms as a base oil of a lubricant with which a gap between a shaft and a sleeve is filled.