• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.13 no.6
• /
• pp.61-65
• /
• 2014

Construction heat insulating material for construction is used in large amounts in industry. In the manufacturing process of this insulation material, a thermal insulation material is completed while a polymer in a liquid state passes through Hall breaker. At this time, the quality and form of a product are determined by a hole in the breaker according to the oil pressure of the fluid and the change of the flow velocity. The friction wear action with regard to partner movement between the two levels of quality of materials affects the performance and the lifetimes of machine parts. In this study of a friction test, SM45C, which is a material used to create brake holes, was used. PVC was used to create the specimen. Moreover, an experiment divided a lubricous state and an unlubricated condition. The resulting value over the load of a pin, the revolving speed of a disk, and the standby state of an experimental result disk could be acquired.

• Composites Research
• /
• v.13 no.6
• /
• pp.55-62
• /
• 2000

The strength test was done for the Carbon/Carbon rotor disk which is the critical part of a carbon/carbon brake system in an operating time. The loading fixture was designed for the static strength test of a single carbon/carbon brake disk using finite element analysis. To simulate the real dynamic system in a static condition, the friction surface of the rotor disk was fixed and static load was applied to the rotor slot in the circumferential direction. The described failure mechanism of the brake disk can be described as matrix cracking occurred first at the contact surface of the rotor slot, subsequent delamination from the cracked contact surface, and the final fracture at the notch of the rotor.

• Tribology and Lubricants
• /
• v.29 no.1
• /
• pp.1-6
• /
• 2013

Hydraulic transmission is the main component delivering power to the drive wheels of an excavator during forward and backward movement, and it has low speed, high torque and high speed, low torque gear change ratios as a forward/backward two-speed main function. It also has additional function of ensuring that the excavator is stably fixed on the ground with the built-in parking brake during excavation operations. In this study, optimal design specifications are determined by modeling and simulating about the multi-disc-type friction clutch, which is the main component improving the reliability of the hydraulic transmission for a 14-ton wheel excavator, and the friction properties of the transmission clutch are analyzed by performing sample tests.

• Tribology and Lubricants
• /
• v.27 no.4
• /
• pp.213-217
• /
• 2011

In this study, friction characteristics using elastomeric actuator with Magneto-rheological (MR) materials are identified. Typically, Magneto-rheological materials are divided into two groups by MR fluid in fluid state and MR elastomer in solid state like rubber. The stiffness characteristics of Magneto-rheological material can be changed as magnetic field is applied. MR fluid has been applied to various industry fields such as to brake, clutch, damper, engine mount and etc. However, MR fluid has been used under the sealed condition to prevent leaking issues. In order to overcome these problems, MR elastomer that has same property as MR fluid has been developed and studied. MR elastomer mainly consists of polymer material such as natural rubber or silicon rubber with particles that can be polarized with magnetic field. And it is called as a smart material since its stiffness and damping characteristics can be changed. In this study, MR elastomer is produced and pin-on-disc tests are carried out to identify the friction characteristics of the material. Several test conditions are applied to evaluate the feasibility to use as a smart actuator in the field of vibration control.

• Journal of Powder Materials
• /
• v.30 no.5
• /
• pp.415-423
• /
• 2023

With the increasing attention to environmental pollution caused by particulate matter globally, the automotive industry has also become increasingly interested in particulate matter, especially particulate matter generated by automobile brake systems. Here, we designed a coating composition and analyzed its mechanical properties to reduce particulate matter generated by brake systems during braking of vehicles. We designed a composition to check the mechanical properties change by adding Cr₃C₂ and YSZ to the WC-Ni-Cr composite composition. Based on the designed composition, coating samples were manufactured, and the coating properties were analyzed by Vickers hardness and ball-on-disk tests. As a result of the experiments, we found that the hardness and friction coefficient of the coating increased as the amount of Cr₃C₂ added decreased. Furthermore, we found that the hardness of the coating layer decreased when YSZ was added at 20vol%, but the friction coefficient was higher than the composition with Cr₃C₂ addition.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.1
• /
• pp.21-30
• /
• 2017

The surface temperature of disc brakes varies during braking, which can affect the friction and wear behavior of braking systems. In order to develop an efficient braking system, the friction and wear behaviors of brake materials need to be clearly understood. In this work, the friction and wear behavior of the C/C-SiC-Cu composite and the Al/SiC composite, which are used in disc braking systems, were investigated. Both the surface temperature and contact pressure were studied. A pin-on-reciprocating tribotester was used for this purpose, in order to control temperature and load. Results showed that the friction varied significantly with temperature and sliding distance. It was found that a transfer layer of compacted wear debris formed on the wear track of the two materials. These layers caused the surface roughness of the wear track to increase. The outcome of this work is expected to serve as a basis for the development of braking systems under various operating conditions.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.15 no.2
• /
• pp.313-318
• /
• 2020

Since the engineering plastics having a melting point of higher than 300 degrees have a high mechanical rigidity, chemical resistance, friction and abrasion performance, those are being highlighted as metal replacement materials in various industries. In this study, 3D printer nozzle with excellent heat dissipation characteristics are designed and analytically verified to form engineering plastics with high melting points in 3D printers based on the melt-lamination modeling method. In order to insulate between the heat block heated to a melting point of filament material and the upper part of the nozzle where the filament is transferred, the heat brake part with low thermal conductivity was designed to have two separate parts, and a cooling fin structure is further applied to the heat brake part to lower steady-state temperature by air convection. Optimized structural design on FDM nozzle part reduces the temperature at the heat sink and at the end part of heat brake by 50% and 14% respectively, compared to the conventional BCnozzle structure.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.786-791
• /
• 2007

Korean high speed train(HSR-350x) has adopted a combined electrical and mechanical(friction) braking system. Brake blending control unit(BBCU) controls each brake system to fulfill the required brake performances such as braking distance, deceleration and jerk. Also the braking system should be designed considering the economical management, such as effective use of generated braking energy and the minimum wear of friction materials(a pad and a brake shoe). In this paper, we establish the disc braking force pattern that reduces the wear of pad in the disc braking system by minimizing the variance of the instantaneous disk baking energy during braking time, and compare the wear mass of pad between the conventional disc braking force pattern and the established results.

• Composites Research
• /
• v.15 no.2
• /
• pp.24-31
• /
• 2002

In this paper, the safety of the crack existing between the load bearing part and the friction part in key slots was evaluated. The repetitive loading test considered impact damage was performed for the various crack models. Also, the probability of the crack propagation and the stress concentration at the crack tip were studied by using a FE analysis. By these method, safety of the disk was confirmed.

• Journal of Institute of Control, Robotics and Systems
• /
• v.16 no.11
• /
• pp.1060-1067
• /
• 2010

In this paper, we present a new type of spherical robot having two arms. This robot, called KisBot, mechanically consists of three parts, a wheel-shaped body and two rotating semi-spheres. In side of each semi-sphere, there exists an arm which is designed based on slider-crank mechanism for space efficiency. KisBot has hybrid types of driving mode: rolling and wheeling. In the rolling mode, the robot folds its arms through inside of itself and uses them as pendulum, then the robot works like a pendulum-driven robot. In the wheeling mode, two arms are extended from inside of the robot and are contacted to the ground, then the robot works like a one-wheel car. The Robot arms can be used as a brake during rolling mode and add friction to the robot for climbing a slope during wheeling mode. We developed a remote controlled type robot for experiment. It contains two DC motors which are located in the center of each semi-sphere for main propulsion, two RC motors for each arm operation, speed controllers for each semi-sphere, batteries for main power source, and other mechanical components. Experiments for the rolling and wheeling mode verify the hybrid driving ability and efficiency of the our proposed spherical robot.