Design and Simulation for Disk-Type Magnetorheological Fluid

Transmission Device

Lifeng Wang, Yiwei Zhang

, Juan Yan and Chuanjiang Li

College of Mechanical Engineering, Chongqing Three Gorges University, Chongqing, China

Keywords: Magnetorheological Fluid, Transmission Device, Mechanism Analysis, Magnetic Circuit Simulation.

Abstract: The magnetorheological fluidtransmission device (MRTD) are chosen as study object for few mature

magnetorheological fluid devices. Firstly, the working principle of MRTD introduced and a disk-type MRTD

is designed based on the magneto-rheological Bingham model. Secondly, the magnetic circuit of MRTD is

designed and the magnetic circuit materials in the device are selected. Finally, the magnetic circuit simulation

are carried out based on finite element analysis software Ansoft Maxwell, thus, the distributions cloud picture

of magnetic field under different excitation currents are obtained.The designed MRTD is able to meet the

working requirements and provides reference and basis for optimal design of magnetorheological fluid

devices.

1 INTRODUCTION

Magnetorheological fluids (MRF) are composed of

micron sized ferromagnetic particles and additives

with modification function dispersed in the carrier

liquid to form a suspension system (Wang, 2015; (Liu,

2013; Cvek, 2020). This system can produce obvious

magnetorheological effect under the action of

magnetic field. When there is no external magnetic

field, it behaves as Newtonian fluid state. When the

external magnetic field is applied, the internal

magnetic particles will form chains along the

direction of the magnetic field within a few

milliseconds, changing from a liquid state to a solid-

like state, showing controllable shear yield strength

(Zhu, 2020). As such transformation is reversible,

rapid and controllable, MRF has been increasingly

applied in automotive brakes, clutches, dampers,

medical instruments, aerospace and other fields

(Desai, 2020; Kim, 2018).

The magnetorheological fluid transmission

device (MRTD) has attracted extensive attention from

scholars at home and abroad because of its simple

control, low energy consumption and short response

time. Since Lord Company developed the first

magnetorheological fluid brake in 1997, the

transmission device has been studied deeply in

foreign countries, and a series of achievements have

been made. Gopalswamy (Gopalswamy, 1998) of

General Motors in the United States successfully

developed the magnetorheological fluid clutch.

Kavlicoglu (GopKavlicoglu, 2007) from University

of Nevada studied the response time and performance

of the magnetorheological fluid limited slip clutch.of

MRF limited slip differential clutch of response time

and performance are analyzed. Great progress has

also been made in the study of magnetic transmission

in China. Meng Weijia (Meng, 2022) carried out the

structural design and simulation experiment of the

double-plate magnetorheological fluid clutch. Guo

Jiangchuan (Guo, 2022) studied the influence of

current, clearance and speed difference on the

transmission performance of magnetorheological

fluid clutch through experiments. Li Xing (Li, 2011)

designed a disc-type magnetorheological soft starting

device and optimized its structural parameters

through magnetic field simulation analysis.

There are many patents related to MRTD or

continuously variable speed device, but there are few

mature products. In this paper, a disc MRTD is

designed, of which the magnetic field are analyzed

and simulated. Magnetic circuit design of MRTD is

verified by magnetic flux density test-bed.

Wang, L., Zhang, Y., Yan, J. and Li, C.

Design and Simulation for Disk-type Magnetorheological Fluid Transmission Device.

DOI: 10.5220/0012142400003562

In Proceedings of the 1st International Conference on Data Processing, Control and Simulation (ICDPCS 2023), pages 23-27

ISBN: 978-989-758-675-0

 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)

2 MECHANISM ANALYSIS OF

MRTD

2.1 Working Principle of MRTD

The working principle of the MRTD is shown in

Figure 1. The driving and driven disks are filled with

magnetorheological fluid and placed in a controllable

magnetic field B. The magnetic field direction is

along the axial direction of the device. Different

magnetic field strengths are obtained by adjusting the

size of the excitation current. The MRF will produce

corresponding rheological effects and can transfer a

certain amount of torque.

Under the action of magnetic field, the

constitutive equation of MRF can be described by

Bingham model, and its expression can be calculated

as follows:

)sgn()(

ττγ

ττηγγττ

≥+= B

Where τ is the shear stress generated by MRF, τ

is the yield stress of MRF, γ is the shear stress of MRF

and η is the viscosity coefficient of MRF. In the figure

1, r

and r

are the inner diameter and outer diameter

of the driving and driven disks respectively. Take a

micro ring with a radial width of d

on the disk with a

radius of r, then the micro torque transmitted by MRF

on the micro ring surface can be expressed as follows:

drrdT

πτ

⋅=

Assume that the speed of the driving disk and

driven disk is ω

and ω

respectively. The shear

stressγcan be calculated as follows:

()=rhrh

ωω ω

=- Δ

From this, it can be concluded that the torque

transmitted by MRTD in the working area is:

)(

rrdrrT

−

+−=⋅=



πτ

2.2 Structure Design of MRTD

The designed MRTD is shown in Figure 2. MRTD is

composed of 1- housing, 2-yoke, 3-coil, 4-magnetic

separator ring, 5-driving disk, 6-bearing seat, 7-

bearing, 8-nut, 9-input shaft, 10-oil seal, 11- driven

disk, 12-hexagon socket bolt and 13-driven disk. The

power is input from the driving shaft, the driving disk

is fixedly connected with the driving shaft, and the

driven disk is fixedly connected with the driven shaft.

MRF is filled between the driving and driven disks,

which is sealed by the fluorine rubber oil seal with

high temperature resistance and good wear resistance.

When the current is applied to the excitation coil, the

working gap between the driving and driven disks

produces a magnetic field, and MRF has a rheological

effect. The power is transferred to the driven disk

through MRF, and then output through the driven

shaft. The torque can be adjusted by controlling the

input current of different excitation coils.

Figure 1: Working principle diagram of MRTD.

ICDPCS 2023 - The International Conference on Data Processing, Control and Simulation

Figure 2: Working principle diagram.

3 MAGNETIC CIRCUIT

ANALYZE AND SIMULATION

OF MRTD

3.1 Magnetic Circuit Design of MRTD

The experiment and research show that the shear

stress formed when the magnetic line of force passes

through the shear direction of MRF vertically is much

greater than that formed when the magnetic line of

force passes through the shear direction of MRF in

parallel. Therefore, the magnetic circuit design has a

crucial influence on the torque that can be transmitted

by the magnetorheological fluid transmission device.

When designing the magnetic circuit, ensure that the

magnetic force line passes through the working gap

formed by the driving and driven disks vertically.

Magnetoresistance is a parameter in the

magnetic circuit of MRTD. Applying current to the

excitation coil can generate magnetic field in the

working area, but when the magnetic flux passes

through the gap in the magnetic circuit, the magnetic

flux density will decrease, because a part of the

magnetic flux is lost in the non gap, forming magnetic

leakage, which leads to the formation of magnetic

resistance in the magnetic circuit. According to Ohm's

law of magnetic circuit, the magnetic resistance of

magnetic circuit is expressed as:

NI L

ΦΦ

===

Where R

is magnetic circuit magnetoresistance

-1

), F

is magnetomotive force (A), Φ is magnetic

flux (Wb), N is total coil turns, I is excitation coil

current (A), L is magnetic circuit length (m), μ Is the

magnetic permeability (H/m), and A is the sectional

plane perpendicular to the magnetic line of force (m

According to the above formula, in order to

reduce the magnetic resistance of the magnetic circuit,

materials with high permeability should be selected

when designing the magnetic circuit of the device.

Permeability reflects the transfer ability of materials

to magnetic lines of force. When designing the

magnetic circuit, materials with high magnetic

permeability should be selected, so that when the

excitation current and the number of winding turns

are the same, the MRF placed in the working gap can

obtain greater magnetic field strength. The drive

device uses a coil with a certain number of turns as

the magnetic field generator, which is used to meet

the required magnetic field strength in the working

area. The selection and design of excitation coil

mainly consider the parameters such as heat loss,

material, wire diameter and turns.

Design and Simulation for Disk-type Magnetorheological Fluid Transmission Device

Table 1: Selection of magnetic conductive materials for main parts.

Part Yoke Driving and driven disks Magnetic separator ring Coil

Material 20#steel 20#steel Aluminium Copper wire

3.2 Selection of Magnetic Circuit

Materials

The selection of magnetic circuit materials has a great

influence on the magnetic field strength obtained in

the working gap of MRTD. Compared with materials

with smaller permeability, materials with higher

permeability can produce larger magnetic field

strength when the excitation current is smaller. Under

the same excitation current conditions, materials with

higher permeability can obtain greater magnetic field

strength, thereby increasing the transmission torque

of the transmission device. The material selection of

the main parts of MRTD is shown in Table 1.

3.3 Magnetic Circuit Simulation of

MRTD

The magnetic circuit design method is usually to

convert or transfer the energy to the closed loop of

limited magnetic flux designed by engineers, which is

assumed to be linear when calculating the magnetic

permeability of materials. This design method adopts

a simple approximate calculation method, which

easily ignores the influence of magnetoresistance,

magnetic leakage, saturation magnetization effect and

material nonlinearity. Therefore, Ansoft Maxwell is

selected for magnetic field design and numerical

simulation. Starting from the essential characteristics

of ferromagnetic materials, the simulation can

accurately obtain the magnetic field distribution of the

device. The steps of Maxwell3D magnetic field

simulation based on Ansoft software are as follows:

establishing and simplifying geometric models,

simplifying the import of geometric models, defining

material properties, selecting magnetic field analysis

mode, specifying boundary conditions, loading

current excitation, setting solution options, numerical

analysis and post-processing, etc.

Figure 3: Distribution of magnetic flux density under different current.

ICDPCS 2023 - The International Conference on Data Processing, Control and Simulation

The number of turns of the excitation coil of MRTD

designed in this paper is 1500 and the clearance

between the master and slave discs is 2mm.When the

excitation current is 0.5A, 1A, 2A, 3A, the magnetic

induction intensity distribution cloud diagram of the

working gap inside the device is shown in figure 3.

When the excitation current is 0.5A, the magnetic

induction intensity distribution cloud diagram of the

working gap is shown in figure 3(a), and the average

magnetic field is about 0.22T. When the excitation

current is 1A, the magnetic induction intensity

distribution cloud diagram of the working gap is

shown in figure 3(b), and the average magnetic field

is about 0.25T. When the excitation current is 2A, the

magnetic induction intensity distribution cloud

diagram of the working gap is shown in figure 3(c),

and the average magnetic field is about 0.38T. When

the excitation current is 3A, the magnetic induction

intensity distribution cloud diagram of the working

gap is shown in figure 3(d), and the average magnetic

field is about 0.62T. At the same time, it can be seen

that the magnetic field distribution in the working area

at the working clearance of the transmission device is

more uniform; When the number of turns of the

excitation coil is a fixed value, the magnetic field

strength in the working area increases with the

increase of the excitation current; When the excitation

current is 3A, the magnetic induction can reach 0.62T,

which meets the requirements of experimental

research.

4 CONCLUSION

In order to promote the development of

magnetorheological fluid devices, a disk-type MRTD

is designed, of which the magnetic field are analyzed

and simulated. The simulation results show that the

magnetic field distribution in the working area of

MRTD is uniform. When the excitation current is 3A,

the average magnetic field strength in the working

area is 0.62T, meeting the design requirements. The

research in this paper can provide reference and basis

for the optimization design of high-power MRTD.

ACKNOWLEDGMENTS

This work is supported by Science and Technology

Research Project of Chongqing Education

Commission (KJQN202001208, KJQN202201241,

KJQN202001211).

CONFLICTS OF INTEREST

The authors confirm that this article content has no

conflict of interest.

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Design and Simulation for Disk-type Magnetorheological Fluid Transmission Device