• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.69-74
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• 2008

The heat generated by the brake system of vehicles results in reduction of friction force on the brake surface and vibration during a braking. To solve these problems, extensive research for the brake shape has been conducted such as drilling cooling holes on the brake disc, accommodating ventilated holes and etc. In this study, we suggest the circumferential pressing type brake disc in order to improve its cooling performance. In order to compare the cooling-down efficiency between the conventional side-pressing type and the circumferential-pressing type, we adopted the FMVSS 105-77 as thermal analysis conditions and This newly proposed concept has been verified using Thermal-structure Coupled Field Analysis along with comparative analysis with the existing ventilated disk.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.367-368
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• 2006

Today, the Artificial Intervertebral Disc (AID) is being developed by increasing the oblique of the endplate gradually. In other words, Ultra-high Molecular Weight Polyethylene (UHMWPE) which is apply to the sliding core of the AID, does not change the shape but alters the oblique of endplate. However, the unreasonable increase of degree of freedom (DOF) can result in the aggravation of the bone fusion and the initial stability and it can also lead to the increase of the concentrated force in core. For these reasons, it is necessary to develop the advanced techniques, which choose the most adequate DOF. In this study, the new optimized modeling of the sliding core and the endplate, the fatigue characteristics, the crack propagation and the formation mechanism of wearing debris was studied and the minimizing technique will be derived from this research.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.820-825
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• 2004

This paper deals with friction-induced vibration of disc brake system under constant friction coefficient. A linear, finite element parameter model to represent the floating caliper disc brake system is proposed. The complex eigenvalues are used to investigate the dynamic stability and in order to verify simulations which are based on the FEM model, the experimental modal test and the dynamometer test are performed. The comparison of experimental and simulation results shows a good agreement and the analysis indicates that mode coupling due to friction force is responsible for disc brake squeal. And squeal type instability is investigated by using the parametric rotor simulation. This indicates parameters which have influence on the propensity of brake squeal. This helped to validate the FEM model and establish confidence in the simulation results. Also they may be useful during real disk brake model.

• The Journal of the Korean dental association
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• v.57 no.4
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• pp.204-212
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• 2019

Introduction : Patients with temporomandibular disorder may have various ear-related symptoms. If an excessive load is applied to the ear area due to the skeletal shape of the mandibular condyle or malposition of the disc, an auditory problems may occur. Case report : The patient was referred to our clinic due to the suspicion of temporomandibular disorder from the local otorhinolaryngology clinic. A few days ago, his right ear could not be heard. MRI showed that the left TMJ disc was anterior displacement with reduction, the right TMJ disc was anteromedial displacement without reduction. Also Right mandibular condyle showed sclerotic bone change, subchondral cyst and was compressing the frontal wall of the ear on MRI view. Right TMJ arthroplasty was done under the diagnosis of right TMJ osteoarthritis and osteochondroma. Postoperative intermaxillary fixation was done with SAS screw and elastics for 2 weeks. One month after the operation, hearing and TMJ discomfort were recovered without any complications. Conclusions As seen in this case, hearing loss due to benign tumor-like lesions of the temporomandibular joint should be treated surgically to restore the TMJ function and hearing.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.2
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• pp.28-34
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• 1998

Powder metallurgy processes are able to form Net-Shape products and have been widely used in the production of automobile parts to improve its productivity. However, because of pores in powder products, the toughness of powder products are generally poor. Therefore, forged products are used in parts which suffer severe fatigue loads. In this paper, the choice of powder materials and production processes such as mixing, compaction, sintering, heat treatment to produce automobile spline hub are studied. Three type of materials are selected and processed and its microstructure and properties are investigated by tensile test, compression ring test, and impact test. Materials and processing methods are selected from the results. Finally, experimental spline hubs are manufactured by selected processes from selected powders and proved by torsional durability test.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.4
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• pp.86-91
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• 2007

The heat generated by the brake system of vehicles results in reduction of friction force on the brake surface and vibration when breaking. These problems play essential part in break's performance. To solve these problems, extensive research has been conducted such as drilling cooling holes on the brake pud, accommodating ventilated holes and etc. In this study, we suggest the compression of brake in circumferential direction in order to improve its cooling performance. And we analyzed comparing temperature distribution which is generated accomplishing heat analysis at each disc.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.6
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• pp.89-94
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• 2011

The wear characteristics between nonmetal and metals have been investigated using a disc on disc system. The specimens of nonmetal are made by the nylon and teflon materials. The specimens of the metal are used as eight kinds of along their hardness. The kinds of metals are copper(Hv96), aluminum(Hv186), brass(Hv234), aluminum bronze(Hv294), stainless steel(Hv327), annealing mild steel(Hv345), mild steel(Hv372), Hard steel(Hv434). In this study, a upper and lower specimens have been used the same size and shape. Using experimental data we figured the relationship between friction coefficient of nonmetal and metals. We figured the relationship between friction temperature of nonmetal and metals. The result had been verified a wear characteristics of nonmetal and metals in the wear tests.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.5
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• pp.544-549
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• 2009

Thermal brake judder caused by the high friction heat of the brake disk. Hot thermal judder makes serious problems such as to be unstability to drivers or to decrease braking force of automobile. Because thermal judder vibration makes high vibration occurrence and thermal deformation of brake disk. Therefore it Is necessary to reduce or eleminate thermal Judder phenomenon by understanding and investigation. This paper introduces the thermal deformation arising from friction heat generation in braking and proposes the FEM analysis to predict the distribution of temperature and thermal deformation. the results of the FEM analysis show the deformed shape and temperature distribution of the disk brake. The optimization is performed to minimize the thermal judder of ventilated disc brake that is induced by the thermal deformation of the disk brake.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.4
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• pp.126-132
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• 2008

The vibration and disturbances from operating the compact disk layer have an effect on the play ability. As the excitation sources of the compact disk player, there are the vibration of the motors and gears, impact by mechanical parts and the external excitations. So, most of the compact disk player have a anti-vibrational system, which is included some rubber or oil dampers. In this study, the vibration characteristics of rubber damper which is used home compact disk player are investigated. The materials and shape of rubber damper are changed, and the transmissibility is measured. As a conclusion, the natural frequency is moved to higher frequency and the transmissibility is reduced by the increasing rubber stiffness. In comparison to butyl rubber damper, the transmissibility of silicon damper was increased by larger restitution elasticity. The hollow damper was effective to reduced the transmissibility.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.961-966
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• 2001

The schematic design process is formulated to develop the vibroisolating rubber mount in optical disc drives. The dynamic model of vibration isolation system is established by using a rigid body with 6 degree of freedom and linear springs with damping property. Considering the practical vibration condition of DVDP(Digital Versatile Disk Player), the required properties of vibroisolating rubber mounts are investigated. Also finite element model of a vibroisolating rubber mount is used to obtain shape design concept and identify the characteristics of a rubber mount which satisfies the required properties from previous design stage. Finally the evaluation method of dynamic properties of vibroisolating rubber mounts is established by utilizing modal test method. Based on the developed process, vibroisolating rubber mounts with a good performance have been developed.