• Tribology and Lubricants
• /
• 제18권4호
• /
• pp.305-311
• /
• 2002

Three different kinds of brake discs including two coated brake discs and one steel disc were tested under the same experimental conditions on a reduced scale braking test bench. A braking test bench was specially designed to analyse thermo-mechanical and frictional behaviors of two types of brake with different sizes in stop and hold braking modes. Plasma spray coating technique was also used to coat the discs with ceramic powder. During the test four commercial brake pads were coupled with discs. Ceramic coated discs showed good stability in friction coefficient at high speed and high energy braking conditions. But they caused large wear loss of pad mass compared with the steel disc. It was shown that thermal barrier effect in ceramic coated discs adjusted the thermal partition between pad and disc. For a steel disc. it showed fluctuating friction coefficient at high speed but small wear loss of pad mass compared with ceramic coated discs.

• 한국공작기계학회논문집
• /
• 제15권1호
• /
• pp.88-94
• /
• 2006

A typical disk brake system consists of caliper housing, piston, seal and two pads etc. The configuration of seal groove, dimension of piston and seal, and seal material properties are important ones for brake performance, as these affect the retraction of piston. The rubber seal is designed to perform dual functions of sealing the brake oil at brake-applied and retracting the caliper piston at brake-released. In this paper, the seal stress is analyzed using Finite Element Method and experiment is conducted by Taguchi's Method. We attempt to quantify the critical design factors in the seal groove and evaluate their impact on some of brake performance factors. The investigation obtained from this study can not only enhance the seal groove design optimization, but also reduce product prototype testing and development time.

• 한국소음진동공학회논문집
• /
• 제19권10호
• /
• pp.1092-1098
• /
• 2009

The squeal propensity of an automotive disc brake system is studied in the theoretical and computational manner. The rotating disc is in contact with two stationary pads and the nonlinear friction is engaged on the contact surface. The friction-coupled equations of motion are derived in the finite element(FE) of the actual brake disc and pad. From the general definition of friction force, the rotation and in-plane mode effects can be included properly in the brake squeal model. The eigenvalue sensitivity analysis and the mode shape visualization at squeal frequencies are also conducted for the detailed investigation. It is found that the squeal propensity is strongly influenced by rotation effect and the in-plane mode can be involved in squeal generation.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 1998년도 제27회 춘계학술대회
• /
• pp.97-107
• /
• 1998

Three different kinds of brake discs including two coated brake discs and one steel disc were tested under the same experimental conditions on a reduced scale braking test bench. Braking test bench was specially designed to analyse thermo-mechanical and frictional behaviors of two sizes of brake discs in stop and hold braking modes. And Plasma spray coating technique was used to coat ceramic powder on the discs. In the test four commercial brake pads were coupled with discs. Ceramic coated discs had shown good stability in friction coefficient at high speed and high energy braking conditions. But they caused large pad mass wear loss compared with the steel disc. It was shown that thermal barrier effect in ceramic coated discs adjusted the thermal partition between pad and disc. For a steel disc, it had shown fluctuating friction coefficient at high speed but a fittie pad mass wear loss compared with ceramic coated discs.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
• /
• pp.26-31
• /
• 2000

There are various noises generated by friction. Among the rest, eliminating squeal noise generated during braking is an important task for the improvement of vehicle passengers' comfort. The parameters affecting brake squeal noise are the material properties of the braking pad, the dynamic properties of the brake parts and the dimensions of the brake assembly etc. Also, the squeal noise changes its inherent form with the normal load and sliding speed. In this study, the characteristics of brake squeal noise generated by friction is analyzed experimentally. The experiment focused on the analysis of friction self-excited vibration and squeal noise level. Friction self-excited vibration is caused by the dry friction between pads and rotor, and occurs as a function of their relative sliding speeds. And Friction self-excited vibration is raised the brake squeal noise.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2002년도 추계학술대회 논문집(II)
• /
• pp.779-786
• /
• 2002

The Friction Brake Pad of High Speed Train is the most important parts in brake system, which is usually made of Cu-based Sintered friction material. This study has been carried out about the formulation effects of sintered friction material and made lots of sample brake pads. Then, we have done the performance test of the developed product by using full scale inertia Dynamo-meter. This performance test (braking speed 300km/h) was conducted as GEC Alsthom Standard test procedure and High Speed Brake Test (braking speed 350km/h) was done at "Poli" in Italy. The friction properties of this product was almost identical with the brake pad which is currently used to TGV. And the temperature of brake disk on braking speed 350Km/h was a little higher.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.396-401
• /
• 2008

The disc-pad brake system is an important part of automobile safety system. During braking, the kinetic energy and potential energies of a moving vehicle are converted into the thermal energy through frictional heat between the brake disc and the pads. Most of the thermal energy dissipated through the brake disc. The temperature could be exceed the critical value for a given material, which leads to undesirable effects, such as the brake fade, premature wear, brake fluid vaporization, bearing failure, thermal cracks, and thermallyexcited vibration. The object of the present study is to investigate temperature field and temperature variation of brake disc and pad during single brake. The brake disc is decelerated at the initial speed with constant acceleration, until the disc comes to stop. The pad-disc brake assembly is built by 3D model with the appropriate boundary condition. In the simulation process, the mechanical loads are applied to the thermomechanical coupling analysis in order to simulate the process of heat produced by friction.

• Tribology and Lubricants
• /
• 제27권2호
• /
• pp.95-100
• /
• 2011

The brake disc materials for railway vehicle have been mainly used cast-iron. The brake disc and pad should be light, resist to a thermal crack and absorb enough friction energy. In order to satisfy this requirement, aluminum alloy brake disc for railway vehicle has been newly developed. The aluminum itself has not been considered the friction material for railway vehicle. However, in the case of aluminum composite with dispersed ceramic particles, friction characteristics, resistance to wear and heat are much improved. In the present study, aluminum composite brake disc of 20% ceramic particle and three kinds of organic pads have been tested in dynamometer. The results show that Al MMC brake disc and pad have good friction coefficient and wear rate, and thermal cracks in brake disc have not been initiated. Also, the Al MMC brake disc can be applied to railway vehicle of 150 km/h.

• Tribology and Lubricants
• /
• 제14권1호
• /
• pp.70-78
• /
• 1998

Two different friction materials (organic and low-metallic pads) for automotive brakes were studied to investigate the anti-fading phenomena during stop. The anti-fading phenomena were pronounced more in the case of using low metallic friction materials than organic friction materials. The main cause of the anti-fading phenomena was the high dependence of friction coefficient on a sliding speed. The anti-fading was prominent when the initial brake temperature was high in the case of low-metallic friction materials due to the strong stick-slip event at high temperature. On the other hand, the anti-fading was not severe in organic friction materials and the effect was reduced at high braking temperature due to the thermal decomposition of organic friction materials. The strong stickslip phenomena of low metallic friction materials at high temperature induced high torque oscillations during drag test. During this experiment two different braking control modes (pressure controlled and torque controlled modes) were compared. The type of the control mode used for brake test significantly affected the friction characteristics.

• 전기전자학회논문지
• /
• 제25권1호
• /
• pp.116-127
• /
• 2021

본 논문에서는 과도 상태 성능 향상이 있는 PLC와 인버터의 동시 제어기법을 제안한다. 기존 기계식 주차설비에서는 PLC만을 활용한 제어 방식이어서 유도전동기에 과전류를 발생시킬 확률이 높고, 브레이크 패드에 마찰로 인한 마모와 손상으로 승차감이 낮아지고, 수명이 단축된다. 이를 개선하기 위해서 PLC와 인버터의 동시 제어를 통한 제어 기법을 적용한 경우 유도전동기에 과전류를 방지하며 브레이크 패드를 보호하고, 승차감 향상, 제어성 상승과 안전성을 확보한다. 제안한 PLC와 인버터의 동시 제어를 통한 제어 방식을 기계식 주차설비에 적용하여 그 타당성을 검증한다.