Vacuum Pump Grease Vibration Damping and Heat Dissipation
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Solution Overview
Problem
Conventional vacuum pumps with ball bearings face challenges in reducing vibration transmission due to insufficient elastic support stiffness, which affects heat radiation performance and longevity.
Innovation Solution
A vacuum pump design featuring a ball bearing supported by elastic members with a soft consistency grease (NLGI No. 1.5 or less) filled in the clearance between the outer ring and the base, along with a heat radiation member for improved thermal conductivity, reduces radial support stiffness and enhances heat radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a gel layer is provided in the clearance between the inner sleeve and outer sleeve to improve heat radiation, then heat radiation performance is improved, but the support stiffness in the radial direction cannot be sufficiently reduced
Solution Approach 1:
The patent changes the physical state parameter of the filling material from gel (solid-like) to grease (semi-fluid), which fundamentally alters both the thermal conduction and mechanical support properties. The grease consistency (NLGI No. 1.5 or less) is specifically selected to achieve low support stiffness while maintaining adequate heat radiation capability through fluid thermal conduction.
Solution Approach 2:
The patent applies hydraulic principles by using grease as a fluid medium to fill the clearance space. The grease acts as a hydraulic cushion that provides elastic support with low stiffness while simultaneously serving as a thermal conduction medium for heat radiation from the ball bearing.
2Object-generated harmful factors
If the elastic modulus is sufficiently reduced to damp vibration, then vibration transmission is reduced, but heat radiation performance deteriorates
Solution Approach 1:
The patent changes the material parameter from solid gel to semi-fluid grease, which has fundamentally different mechanical and thermal properties. The grease's low viscosity and fluidity enable it to act as an effective vibration damper while its thermal conduction properties maintain heat radiation capability.
Solution Approach 2:
The grease serves as an intermediary substance that mediates between the ball bearing and the outer sleeve. It provides vibration damping through its fluid characteristics while simultaneously conducting heat away from the ball bearing, thus resolving the contradiction between vibration reduction and heat radiation.
3Strength
If soft consistency grease is used to reduce support stiffness, then vibration damping is improved, but grease may flow out of the clearance region
Solution Approach 1:
The patent specifies a particular grease consistency range (NLGI No. 1.5 or less) that balances fluidity for vibration damping with sufficient viscosity to prevent leakage. This parameter optimization ensures the grease remains in the clearance region while providing the desired low stiffness support.
Solution Approach 2:
The grease is specifically applied in the clearance region between the ball bearing and outer sleeve, where it provides localized vibration damping. The elastic members provide structural containment in this specific region, creating a localized system where the grease's soft consistency benefits vibration reduction without causing leakage problems.
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 effectively reduces vibration transmission while maintaining heat radiation performance and extending the lifespan of the grease by preventing evaporation and deterioration.
Implementation Method 1
a grease which is filled between the outer ring and the holding section, the grease having a consistency of NLGI No. 1.5 or less
Implementation Method 2
a heat radiation member including a contact section being in contact with the outer ring and a heat radiation section extending from the contact section and disposed in the region filled with the grease, the heat radiation member having a higher thermal conductivity than the outer ring
Implementation Method 3
a holding section which elastically holds an outer ring of the ball bearing
Data Source
AI summary
A vacuum pump comprises: a ball bearing which supports a rotor; a holding section which elastically holds an outer ring of the ball bearing; and a grease which is filled between the outer ring and the holding section, the grease having a consistency of NLGI No. 1.5 or less.