• 제목/요약/키워드: wheel & axle

검색결과 145건 처리시간 0.035초

의자차 뒷바퀴 축의 위치에 따른 의자차 추진력과 지구력 (The Force and Endurance During Wheelchair Propulsion by Three Different Rear Axle Positions)

  • 이미영;김수일
    • 한국전문물리치료학회지
    • /
    • 제10권2호
    • /
    • pp.1-10
    • /
    • 2003
  • This study was carried out to help the comprehensive rehabilitation of spinal cord injuries by measuring propulsion force and endurance exerted on wheelchair handrims, and predicting the differences among three different rear axle positions. The BTE (Baltimore Therapeutic Exerciser) work simulator was used on 9 paraplegia to test the force and endurance during wheelchair propulsion. The 141 large wheel of the BTE work simulator and a standard wheelchair with removed handrims were used for simulating wheelchair propulsion. The neurological and demographical characteristics of the patients were collected by personal interviews and direct examinations. The Kruskal-Wallis test was used to compare force and endurance among the groups. The strongest maximum isometric strength was produced when the rear axle of the wheelchair and the acromion process were on the same coronal plane. Although there were no significant differences statistically, moving the rear axle forward did result in greater isotonic strength. The research suggests that better functional activity of persons with paraplegia is possible when the rear axle of the wheelchair is appropriately adjusted.

  • PDF

완화 홈이 가공된 액슬구동축의 응력집중 및 피로수명 평가 (Investigation of Stress Concentration and Fatigue Life of Axle Drive Shaft with Relief Groove)

  • 신재명;한승호;한동섭
    • 한국기계가공학회지
    • /
    • 제11권1호
    • /
    • pp.88-94
    • /
    • 2012
  • An axle drive shaft with double joint shaft, cross kit and yoke has an important role by transferring power and changing steering angle between axle and wheel in power train system. It has been used widely in the heavy machinery requiring a high reliability in the power train system. At fatigue failures of the axle drive shaft with the long span, a relatively high stress concentration at a snap ring groove on the drive shaft brings to significant fatigue damages under repeated loading condition. As Peterson's suggestions on this study, a relief groove in the vicinity of the snap ring groove is applied by decreasing the stress concentration and improving the fatigue life of axle drive shaft. By using FEM analysis, the decreasing effect of the stress concentration and extended fatigue life are due to the change of design parameters related with size and location of the relief groove. The relief groove with the design parameters such as d/b=2.0 and r/h=1.2 enables to decrease the stress concentration of 22.3% and increase the fatigue life more than 3 times by comparing with no relief groove application.

페룰의 연삭 가공 특성에 관한 연구 (A Study of Grinding Characteristic of Ferrule)

  • 이석우;최헌종;최영재;안건준
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2003년도 춘계학술대회
    • /
    • pp.974-979
    • /
    • 2003
  • As recently optical communication industry is developed, request of optical communication part is increased. Ferrule is very important part which determines transmission efficiency and quality of information in the optical communication part. Most of ferrule processes are grinding which request high processing precision. Particularly, concentricity and cylindricity of inner and outer diameter is very important. The co-axle grinding process of ferrule is to make its concentricity all of uniform before centerless grinding. Surface integrity of ferrule is affected by kind of grinding wheels, grinding conditions, and characteristic of workpiece and equipment. In this study, surface integrity of workpiece according to change of grinding wheel speed, feed rate, regulating wheel speed and grinding force is investigate to improve the concentricity and roundness of ferrule from many experiments.

  • PDF

자동차 휠 동력계의 하중 검출 신호 처리 방법 (Load Measurement Algorithm for a Vehicle Wheel Dynamometer)

  • 이진성;정규원
    • 한국생산제조학회지
    • /
    • 제26권4호
    • /
    • pp.418-424
    • /
    • 2017
  • A wheel dynamometer was installed between the rim and axle hub to measure the forces and moments applied to a vehicle. The wheel dynamometer was composed of sensing and signal processing components. Because the sensing component contained a complex structure to sense the six components of the forces and moments and the wheel rotated along with the vehicle movement, sophisticated signal processing hardware and a software algorithm were used. The strains and the calibration matrices of the wheel dynamometer along the wheel rotation angle were investigated using FEM. From the analysis, the calibration matrices were simplified using a spline interpolation. Based upon these results, the signal processing component could be effectively designed and the firmware software could be simplified.

철도차량 차축 재료의 파괴특성 적외선열화상 모니터링 (Infrared Thermographic Monitoring for Failure Characterization in Railway Axle Materials)

  • 김정국
    • 비파괴검사학회지
    • /
    • 제30권2호
    • /
    • pp.116-120
    • /
    • 2010
  • 차축과 차륜으로 구성되는 철도차량 윤축은 차량의 운행과 관련하여 안전과 직결되는 중요한 철도 부품의 하나이다. 본 연구에서는 철도차량의 차축 재료의 인장파괴거동에 대한 특성을 분석하였다. 20년 이상 운행된 전기기관차 및 디젤전기기관차의 차축 시편에 대하여 연장시험을 수행하였다. 인장시험 동안 시편의 파괴특성을 모니터링하기 위해 고속 적외선카메라가 사용되었는데, 인장시험 동안의 시편 표변의 온도 변화를 모니터링하여 온도 분포로부터 인장파괴거동을 설명하고 파괴모드를 규명하고자 하였다.

Development and performance evaluation of lateral control simulation-based multi-body dynamics model for autonomous agricultural tractor

  • Mo A Son;Hyeon Ho Jeon;Seung Yun Baek;Seung Min Baek;Wan Soo Kim;Yeon Soo Kim;Dae Yun Shin;Ryu Gap Lim;Yong Joo Kim
    • 농업과학연구
    • /
    • 제50권4호
    • /
    • pp.773-784
    • /
    • 2023
  • In this study, we developed a dynamic model and steering controller model for an autonomous tractor and evaluated their performance. The traction force was measured using a 6-component load cell, and the rotational speed of the wheels was monitored using proximity sensors installed on the axles. Torque sensors were employed to measure the axle torque. The PI (proportional integral) controller's coefficients were determined using the trial-error method. The coefficient of the P varied in the range of 0.1 - 0.5 and the I coefficient was determined in 3 increments of 0.01, 0.05, and 0.1. To validate the simulation model, we conducted RMS (root mean square) comparisons between the measured data of axle torque and the simulation results. The performance of the steering controller model was evaluated by analyzing the damping ratio calculated with the first and second overshoots. The average front and rear axle torque ranged from 3.29 - 3.44 and 6.98 - 7.41 kNm, respectively. The average rotational speed of the wheel ranged from 29.21 - 30.55 rpm at the front, and from 21.46 - 21.63 rpm at the rear. The steering controller model exhibited the most stable control performance when the coefficients of P and I were set at 0.5 and 0.01, respectively. The RMS analysis of the axle torque results indicated that the left and right wheel errors were approximately 1.52% and 2.61% (at front) and 7.45% and 7.28% (at rear), respectively.

틸팅열차의 원곡선부 주행시 안전성 평가 (Safety evaluation of tilting train on circular curve)

  • 김상수;엄기영;배재형
    • 한국철도학회:학술대회논문집
    • /
    • 한국철도학회 2010년도 춘계학술대회 논문집
    • /
    • pp.1703-1712
    • /
    • 2010
  • The safety of tilting train running on curved track is, in general, evaluated with a derailment coefficient calculated by the ratio of wheel load and lateral force, Particularly on curve, the wheel load and lateral force on rail may cause trackbed to be deformed, depending on their intensity, and moreover, often result in critical accident such as derailment. This study hence was intended to identify the cause of wheel load and lateral force so as to suggest the allowable wheel load reduction rate, lateral force limit and derailment coefficient, thereby quantitatively evaluating the operational safety of tilting train. This study therefore was aimed to analyze the wheel load and lateral force occurred during tilting train's operation on circular curve in such a way of comparing with traditional trains, by axle and speed, in a bid to eventually evaluate the operational safety of tilting train.

  • PDF

Stress Analysis in the Elastic-Plastic Analysis of Railway Wheels

  • Ashofteh, Roya Sadat;Mohammadnia, Ali
    • International Journal of Railway
    • /
    • 제7권1호
    • /
    • pp.1-7
    • /
    • 2014
  • Fatigue and wear in wheels is often due to the forces and loading. These certainly have fundamental effects on reducing the wheel life and increasing the costs related to repairing and maintenance. Modeling and stress analysis of a wheel sample existing in the Iranian fleet have been performed in its contact with U33 and UIC60 rails. The results have been reviewed and analyzed in elastic and elastic-plastic phase and under static (railcar weight) and quasi static loads. Moreover, effects of wheel diameter, axle load, wheel material, rail type are analyzed.

차륜 불평형이 있는 철도차량의 동적해석 (Dynamic Analysis of Railway Vehicle with Wheel Unbalance)

  • 이승일;최연선
    • 대한기계학회논문집A
    • /
    • 제37권11호
    • /
    • pp.1387-1395
    • /
    • 2013
  • 차륜 불평형은 차륜의 무게중심이 윤축의 기하학적 중심축에서 벗어나 있을 때 발생한다. 차륜 불평형을 수정하지 않고 주행하면 불평형에 의한 원심력이 차체의 진동을 발생시키게 되며 차륜의 마모를 촉진시키거나 차축 베어링에 손상을 주게 된다. 본 연구에서는 철도차량 동적해석을 통하여 차륜 불평형이 차량 임계속도와 차체 진동에 미치는 영향을 검토하였다. 차륜 불평형은 임계속도를 감소시키고 차체 공진을 유발할 수 있음을 알 수 있었다. 또한 차륜의 정적, 동적 불평형에 따른 차체진동을 해석함으로써 불평형 수정은 양면 밸런싱이 필요함을 밝혔다.

접지면 중앙에서 3차원 방향의 충격 가진에 의한 타이어의 3차원 진동형이 축에 미치는 영향 (3-D Vibration Modes of the Tire in Ground Contact and Its Effects on Axle When Excited by a 3-D Impact at the Center of Contact Patch)

  • 김용우;남진영
    • 한국자동차공학회논문집
    • /
    • 제11권6호
    • /
    • pp.171-182
    • /
    • 2003
  • Tire vibration modes are known to play a key role in vehicle ride and comfort characteristics. Inputs to the tire such as impacts, rough road surface, tire nonuniformities, and tread patterns can potentially excite tire vibration. In this study, experimental modal analysis on the tire in ground contact are performed by a 3-D impact at the center of contact patch to investigate which modes of tire influence the vibration of wheel and axle. Through the experiment, the vibration transmission properties from tire to axle are examined. And we have compared the influential tire modes when the tire is excited by a vertical impact with those when excited by the 3-D impact. Additionally, the modes of ground contact tire are compared with those of the suspended tire.