• Title/Summary/Keyword: clamping force

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An Experimental Study of Vibrator Amplitude Change for a Clamping Force Dispersion and Friction Coefficient Decrease (체결력 산포와 마찰계수의 감소를 위한 가진기의 진동량 변화 실험)

  • Lee, Geum-Gang;Moon, Seok-Man;Cho, Yong-Joo
    • Tribology and Lubricants
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    • v.27 no.6
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    • pp.332-337
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    • 2011
  • The object of this experimental study is to investigate influences of vibrator amplitude on clamping force in vibration for bolted joint. The experiment is that change the vibrator amplitude to check clamping force. also the friction coefficient calculated by equation to use an obtained in experiments. The main purpose of generation vibrations is decreasing the clamping force dispersion. also If vibration occurs while tightening the bolt is reduced coefficient of friction. In this paper, In experiments to measure the clamping force before vibrator's amplitude changing. Vibrator's amplitude changes to 5.5mm from 4.4mm. As a result, under various vibration condition, relationship of clamping force and Vibrator amplitude.

The Effect of Clamping Angle of a Locker on the Clamping Force of the Wedge Type Rail Clamp (Locker 의 물림각이 쐐기형 레일클램프의 압착력에 미치는 영향 평가)

  • Han D.S.;Lee S.W.;Han G.J.;Ahn C.W.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.1042-1045
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    • 2005
  • The wedge type rail clamp has the operating mechanism: First, the jaw pad clamps a rail with small clamping force. Next as the wind speed increases, the clamping force of the Jaw pad Is Increased by the wedge. The initial clamping force of a jaw pad was determined by the clamping angle of a locker. In this study, we carried out the finite element analysis to evaluate the relationship between the clamping angle of a locker and the clamping force of a jaw pad with respect to the design wind speed, such as 2, 4, 6, 8, and 10m/s, we adopted the wedge type rail clamp fur 50tons class container crane with the wedge angle of $10^{\circ}$.

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Finite Element Analysis of Residual Stress by Cold Expansion Method with Clamping Force in the Plate having Adjacent Holes (인접홀에서 홀확장법과 체결력 고려시, 발생하는 잔류응력 분포에 대한 유한요소해석)

  • Yang Won-Ho;Cho Myoung-Rae;Jang Jae-Soon
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.5 s.182
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    • pp.149-154
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    • 2006
  • The cold expansion method (CEM) is one of the widely used a method to improve the fatigue behavior of materials in aerospace industry. Such improvement is due to the compressive residual stress developed when a tapered mandrel goes through the fastener holes a little smaller than the mandrel. CEM is retarded of crack initiation due to the compressive residual stress developed on the hole surface. Many researchers are studied a finite element analysis of residual stress around fastener hole. But in case of real model, fastener hole has a clamping force after CE. Therefore, it is respected that residual stress distributions should be changed due to clamping forces. In this paper, it was performed finite element analysis of residual stress by clamping force after CE in the plate having adjacent holes. From this study, it has been found that compressive residual stress near the hole increases according to clamping force. Also, the more increase clamping force, the more increases compressive residual stress. However, tensile residual stress increase beyond clamping force area.

A Study on the Clamping Improvement of Precision Screws according to the Materials and Thread Changes (소재와 나사산 변화에 따른 정밀나사의 체결력 향상에 관한 연구)

  • Hwang, Woo Chae;Ra, Seung Woo
    • Journal of the Korean Society for Precision Engineering
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    • v.32 no.6
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    • pp.503-507
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    • 2015
  • In this study, we compare the performance of the screw through the Clamping force of the test materials to change shape and structure, one of the ways to maintain and improve the engaging force to cope with the miniaturization of the fastener threads are further thinner and lighter precision way that can improve the fastening force of the screw results were as follows. The clamping force according to the materials was $7.57N{\cdot}cm$ in SUS XM7 and SWCH18A was $5.97N{\cdot}cm$. This result was to be found to average 13.5% high in the Clamping force of SUS XM7 materials. In the case of the clamping force of the screw thread shape change, the clamping force of symmetrical and asymmetrical thread was $6.78N{\cdot}cm$ and $7.57N{\cdot}cm$. The clamping force of the asymmetrical thread showed an average high of 11.6%.

Influence of Initial Clamping Force of Tension Clamp on Performance of Elastic Rail Fastening System (텐션클램프의 초기 체결력이 탄성레일체결장치의 성능에 미치는 영향)

  • Lee, Dong Wook;Choi, Jung Youl;Baik, Chan Ho;Park, Yong Gul
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.3
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    • pp.1243-1251
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    • 2013
  • The purpose of this study is to investigate the influence of initial clamping force of tension clamp on the performance of an elastic rail fastening system used in sharp curve track. In this study, the initial clamping force and the increasing lateral wheel loads were conducted in the analytical and experimental study, i.e., finite element analysis, laboratory and field test. Using the analytical and experimental results, the performance of the tension clamp was investigated. It was found that the stress of tension clamp depends on the initial clamping force. Therefore the initial clamping force appeared to directly affect the compression stress of the tension clamp. It was found that the compression stress of tension clamp was transferred to the tensile stress by applied the lateral wheel load in service sharp curve track. Further, it was concluded that the initial clamping force was applied on the strengthening force for the tension clamp and then the appropriate initial clamping force was important to ensure a stable performance and long term endurance of tension clamp.

Relationship between the Initial Clamping Force and the Sliding Distance of the Rail Clamp according to the Wedge Angle (쐐기각에 따른 레일클램프의 초기 압착력과 밀림거리 사이의 관계)

  • Han D.S.;Lee S.W.;Kwon S.K.;Han G.J.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.379-380
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    • 2006
  • In this study we dealt with the relationship between the initial clamping force and the sliding distance in the wedge type rail clamp. The sliding distance is determined by the wedge angle and the initial clamping force. In order to derive the relation formula between the wedge angle and the sliding distance, we ad opt 5-kinds of the wedge angle, such as 2, 4, 6, 8, $10^{\circ}$. And then we analyze the effect of the initial clamping force on the sliding distance.

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A Clamping Force Estimation Method in Electric Parking Brake Systems (전자 제어식 주차브레이크 시스템의 제동력 추정 기법)

  • Jang, Min-Seok;Lee, Young-Ok;Lee, Won-Goo;Lee, Choong-Woo;Son, Young-Sup;Chung, Chung-Choo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.12
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    • pp.2291-2299
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    • 2008
  • Hall effect force sensors have been used to measure clamping force in conventional Electric Parking Brake(EPB) systems. Estimation of clamping force without the sensors has drawn attentions due to mounting space limitations and cost issues. Removing the sensor requires the estimation of the initial contact point where the clamping force is effectively applied to the brake pads. In this paper, we propose how to estimate the initial contact point finding the relation between the angular velocity of an actuator and the initial contact point. For force estimation a look-up table is used as a function of the displacement of parking cable from the initial contact point. The proposed method is validated by experiments. From the experimental results we observe that the proposed method satisfies the specifications. The designed method is also able to estimate clamping force although parking cables are loosened and brake pads are worn out. Applying the proposed method enables manufacturing of low cost EPB systems.

A Study on the Clamping Force Estimation and Failsafe Control Algorithm Design of the Electronic Wedge Brake System (Electronic Wedge Brake 시스템의 클램핑력 추정 및 Failsafe 제어 알고리즘 설계에 관한 연구)

  • Chung, Seunghwan;Lee, Hyeongcheol
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.1
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    • pp.16-23
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    • 2016
  • The EWB(electronic wedge brake) is one in which the braking force is developed in a wedge and caliper system and applied to a disk and wedge mechanism. The advantage of the wedge structure is that it produces self-reinforcing effect and hence, utilizes minimal motor power, resulting in reduced gear and current. The extent of use of clamping force sensors and protection from failure of the EWB system directly depends on the level of vehicle mass production. This study investigated the mathematical equations, simulation modeling, and failsafe control algorithm for the clamping force sensor of the EWB and validated the simulations. As this EWB system modeling can be applied to motor inductance, resistance, screw inertia, stiffness, and wedge mass and angle, this study could improve the accuracy of simulation of the EWB. The simulation results demonstrated the braking force, motor speed, and current of the EWB system when the driver desired to the step and pulse the brake force inputs. Moreover, this paper demonstrated that the proposed failsafe control algorithm accurately detects faults in the clamping force sensor, if any.

Creative Design of the Wedge Type Rail Clamp to set the Initial Clamping Force (초기압착력 설정을 위한 쐐기형 레일클램프의 창의적 설계)

  • Han, Dong-Seop;Kim, Yong;Lee, Seong-Wook;Han, Geun-Jo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.6 no.3
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    • pp.58-64
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    • 2007
  • The clamping force of a jaw pad is determined by the displacements of main part when two lockers are locked, after the clamping angle of a locker was set up in the wedge type rail clamp for a container crane. In this time, if the resistance of wedge frame generates due to several factors, the clamping angle of a locker to display the initial clamping force will be changed because of the reduction of displacement of extension bar. This resistance is determined by the eccentric distance between the roller and the wedge, and by the gap between the wedge frame and outer frame. In this study we measured the tensile force of both extension bar through the performance test of the prototype rail clamp in order to evaluate the effect of the resistance of wedge frame on the clamping force of the wedge type rail clamp.

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Evaluation of Clamping Characteristics for Subminiature Screws According to Thread Angle Variation (초소형 나사의 나사산 각도변화에 따른 체결특성 평가)

  • Min, Kyeong Bin;Kim, Jong Bong;Park, Keun;Ra, Seung Woo
    • Journal of the Korean Society for Precision Engineering
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    • v.31 no.9
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    • pp.839-846
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    • 2014
  • Recent trends in the miniaturization and weight reduction of portable electronic parts have driven the use of subminiature screws with a micrometer-scale pitch. As both screw length and pitch decrease in subminiature screws, the resulting clamping force becomes diminishes. In this work, Finite element (FE) analysis is performed to evaluate clamping force of a screw assembly, with a comparison with experimental result. To improve clamping force of subminiature screws, a new screw design is considered by modifying screw thread angle: the thread angle is varied as an asymmetric way unlike the conventional symmetric thread angle. FE analyses are then performed to compare the clamping characteristics of each subminiature screw with different thread angle. The effect of thread angles on the clamping force is then discussed in terms of structural safety for both positive and negative screws.