CN-122029262-A - Magnetorheological fluid and mechanical device

CN122029262ACN 122029262 ACN122029262 ACN 122029262ACN-122029262-A

Abstract

The invention provides a magnetorheological fluid and a mechanical device which have small viscosity when not excited, good resistance when excited and improved lubricity. A magnetorheological fluid comprises magnetic particles and a dispersion medium, wherein the dispersion medium comprises base oil and double-terminal higher fatty acid ester modified silicone oil and/or side chain type higher fatty acid ester modified silicone oil.

Inventors

Ishizaki Hiroku
LUO HEMING

Assignees

索马龙株式会社

Dates

Publication Date: 20260512
Application Date: 20241029
Priority Date: 20231110

Claims (6)

1. A magnetorheological fluid comprising magnetic particles and a dispersion medium, The dispersion medium comprises a base oil and a double-terminal higher fatty acid ester-modified silicone oil, and/or a side chain-type higher fatty acid ester-modified silicone oil.
2. The magnetorheological fluid of claim 1, wherein, The higher fatty acid in the double-terminal higher fatty acid ester modified silicone oil and the side chain higher fatty acid ester modified silicone oil is saturated fatty acid with 13-20 carbon atoms and/or unsaturated fatty acid with 13-20 carbon atoms.
3. The magnetorheological fluid of claim 1, wherein, The higher fatty acid esters in the double-terminal higher fatty acid ester modified silicone oil and the side chain higher fatty acid ester modified silicone oil are fatty acid esters composed of saturated fatty acids with 13-20 carbon atoms and/or unsaturated fatty acids with 13-20 carbon atoms and methyl.
4. The magnetorheological fluid of claim 1, wherein, The total content of the double-terminal higher fatty acid ester-modified silicone oil and the side chain higher fatty acid ester-modified silicone oil is 0.8-10% by mass relative to the total amount of the magnetorheological fluid.
5. The magnetorheological fluid of claim 1, wherein, The magnetorheological fluid further comprises an anti-wear agent.
6. A mechanical device using the magnetorheological fluid according to any one of claims 1 to 5.

Description

Magnetorheological fluid and mechanical device Technical Field The present invention relates to magnetorheological fluids and mechanical devices. And more particularly, to a magnetorheological fluid and a mechanical device for controlling frictional force acting between objects in various mechanical devices such as a brake, a clutch, a vibration isolator, and a damper of a vibration damper. Background Magnetorheological (Magneto Rheological: MR) fluid is a fluid in which magnetic particles such as magnetizable metal particles are dispersed in a dispersion medium. When no magnetic field is applied, the magnetorheological fluid has magnetic particles randomly suspended in a dispersion medium and functions as a fluid. On the other hand, when a magnetic field is applied, the magnetic particles form many clusters to be thickened, and the internal stress increases. Magnetorheological fluid acts like a rigid body due to the increase in internal stress, and exhibits resistance to shear flow and pressure flow. With such characteristics, magnetorheological fluids are used in various mechanical devices such as brakes, clutches, vibration isolators, dampers of vibration dampers, and the like, in order to control frictional forces acting between objects. Therefore, when a magnetic field is not applied to the magnetorheological fluid (when not excited), the drag resistance (viscous resistance) is required to be small, and therefore, the smaller the viscosity of the magnetorheological fluid is, the more preferable. On the other hand, when a magnetic field is applied to the magnetorheological fluid (when excited), the greater the resistance to the shear flow and the pressure flow (hereinafter also referred to as "resistance when excited") is more preferable. The resistance at the time of excitation was evaluated by measuring a torque value, viscosity, shear stress, or the like. In the present specification, the resistance at the time of excitation is evaluated by measuring the viscosity at the time of excitation. Patent document 1 proposes a magnetorheological fluid in which a carrier liquid contains predetermined amounts of magnetic particles, a clay mineral dispersion stabilizer, and a surfactant. Prior art literature Patent literature Patent document 1 Japanese patent laid-open publication No. 2002-121578 Disclosure of Invention Problems to be solved by the invention However, the magnetorheological fluid described in patent document 1 has a small viscosity when no magnetic field is applied, but has a small resistance when excited, which is unsatisfactory. Further, if the magnetic particles are added to increase the resistance during excitation, there is a problem that the lubricity of the magnetorheological fluid is lowered and the abrasion resistance is adversely affected. The present invention has been made in view of the above-described problems, and an object thereof is to provide a magnetorheological fluid and a mechanical device which have a low viscosity when not excited, have a good resistance when excited, and have improved lubricity. Solution for solving the problem In order to solve the above-mentioned problems, the present invention is defined as the following [1] to [6]. [1] A magnetorheological fluid comprising magnetic particles and a dispersion medium comprising a base oil and a di-terminal higher fatty acid ester-modified silicone oil, and/or a side chain higher fatty acid ester-modified silicone oil. [2] The magnetorheological fluid according to the item [1], wherein the higher fatty acid in the double-terminal higher fatty acid ester-modified silicone oil and the side chain higher fatty acid ester-modified silicone oil is a saturated fatty acid having 13 to 20 carbon atoms and/or an unsaturated fatty acid having 13 to 20 carbon atoms. [3] The magnetorheological fluid according to [1] or [2], wherein the higher fatty acid ester in the double-terminal higher fatty acid ester-modified silicone oil and the side chain higher fatty acid ester-modified silicone oil is a fatty acid ester composed of a saturated fatty acid having 13 to 20 carbon atoms and/or an unsaturated fatty acid having 13 to 20 carbon atoms and a methyl group. [4] The magnetorheological fluid according to any one of the above [1] to [3], wherein the total content of the double-terminal higher fatty acid ester-modified silicone oil and the side chain higher fatty acid ester-modified silicone oil is 0.8 to 10 mass% relative to the total amount of the magnetorheological fluid. [5] The magnetorheological fluid of any one of [1] to [4], further comprising an abrasion resistant agent. [6] A mechanical device using the magnetorheological fluid of any one of the above [1] to [5 ]. Effects of the invention According to the embodiment of the present invention, a magnetorheological fluid and a mechanical device having a small viscosity when not excited, a good resistance when excited, and improved lubricity can be provided. Detailed Description The