Electrorheological Fluids
Electrorheological(ER) fluids are of high interest because potentially they can provide simple, quiet, and fast interfaces between electrical controls and mechanical systems. However, a problem with ER fluids to date is that the yield strength is too low for many practical applications. The main drawback of this approach is that the large dielectric contrast between the solid particles and the fluid can give rise to a large electrical current and breakdown.
In the present invention, a new idea is proposed whereby the extremely large electric field usually present in a electrolytic double layer is harnessed to advantage, giving yield strength of the novel materials reaches a 50kPa high. The new ER solid particles fabricated consists of high dielectric nano-particles with an average diameter of 70nm, which are surface activated so that the surface ions are mobile, forming a electrolytic double layer. The experimental results and theorectical calculation shown that the new class ionic ER fluids are one order of magnitude better than those available on the market, with very little electrical power requirement.
1. The fabrication methodology is very simple and low cost mass production is easily achievable
2. The liquid-solid transformation is completely reversible and can be achieved within 10 milliseconds
3. Low current even under high electric field, thus low power consumption
4. The viscosity of the suspension is low in the absence of an electric field
5. Small size particles resolve the problem with sedimentation
- Applications related to motion transmission
- Electrical vehicles of the future
- As microgears for motor devices
Patent Number: US6852251B2
Application Number: US2002243668A
Inventor: Sheng, Ping | Wen, Weijia | Chan, Che Ting | Ge, Weikun | Yang, Shihe
Priority Date: 16 Sep 2002
Priority Number: US6852251B2
Application Date: 16 Sep 2002
Publication Date: 8 Feb 2005
IPC Current: C07C005141 | C07C005507 | C07F001900 | C10M010102 | C10M010504 | C10M010506 | C10M010708 | C10M010750 | C10M013316 | C10M013320 | C10M013900 | C10M016904 | C10M017100 | C10N001002 | C10N001004 | C10N001008 | C10N002006 | C10N004014
US Class: 252512 | 252073 | 252500 | 2525181 | 2525191
Assignee Applicant: The Hong Kong University of Science & Technology
Title: Electrorheological fluids
Usefulness: Electrorheological fluids
Summary: The fluid is used for electrorheological system (claimed). It can be used in automotive clutches, ABS brakes, shock absorption, vibration damping and micro-electric mechanical systems.
Novelty: Electrorheological fluid for e.g. automotive brakes, shock absorption and vibration damping, comprises composite particles suspended in electrically insulating hydrophobic liquid, where the composite particles are metal salts
Chemical/Material
Chemical/Material Application
16 Sep 2002
US 6852251
TTC.PA.173
Hong Kong
