Wheel Imbalance Research Articles

Influence of pollution of passenger car wheels on the quality of their balance

The article has a methodological intent, which consists in the desire to digitize the degree of influence of contamination of the wheel rims of passenger cars on the quality of their balancing. In a specific study, other aspects that influence the magnitude of the residual imbalance of wheels of cars and SUVs will be omitted, such as: the production of metal components of the machine (shaft, cone, flange), the central hole of the wheel rims, the difference in the angle of attack of the cones, the use of finger adapters and others. These parameters are taken as a constant; we will consider the effect of only dirt on the wheels of various cars. Three cars took part in the experiment: Lada Largus, UAZ Patriot, BMW X4M Competition. Keywords road transport, wheel, operation, balancing stand, safety, wheel imbalance, wheel washing, road safety

Rotary dressing and cylindrical grinding simulation for lead pattern prediction

A kinematic model of rotary dressing - cylindrical grinding for lead pattern prediction is presented. Analysis of dressing and grinding parameters, dressing forces, and wheel imbalance effects has been conducted, providing a comprehensive look at the interrelationships between them and the resulting lead pattern. For model validation, a series of experimental tests has been performed, where workpiece and simulation lead has been characterized according to MBN 31,007–7 standard. Results emphasize the significance of modelling and translate it into a useful tool for selecting optimal dressing and grinding parameters for achieving specific surface qualities where lead is minimised or eliminated.

Diagnosis of the Pneumatic Wheel Condition Based on Vibration Analysis of the Sprung Mass in the Vehicle Self-Diagnostics System.

This paper presents a method for the multi-criteria classification of data in terms of identifying pneumatic wheel imbalance on the basis of vehicle body vibrations in normal operation conditions. The paper uses an expert system based on search graphs that apply source features of objects and distances from points in the space of classified objects (the metric used). Rules generated for data obtained from tests performed under stationary and road conditions using a chassis dynamometer were used to develop the expert system. The recorded linear acceleration signals of the vehicle body were analyzed in the frequency domain for which the power spectral density was determined. The power field values for selected harmonics of the spectrum consistent with the angular velocity of the wheel were adopted for further analysis. In the developed expert system, the Kamada-Kawai model was used to arrange the nodes of the decision tree graph. Based on the developed database containing learning and testing data for each vehicle speed and wheel balance condition, the probability of the wheel imbalance condition was determined. As a result of the analysis, it was determined that the highest probability of identifying wheel imbalance equal to almost 100% was obtained in the vehicle speed range of 50 km/h to 70 km/h. This is known as the pre-resonance range in relation to the eigenfrequency of the wheel vibrations. As the vehicle speed increases, the accuracy of the data classification for identifying wheel imbalance in relation to the learning data decreases to 50% for the speed of 90 km/h.

Modelling of Off-Road Truck Tire-Rim Slip Using Finite Element Analysis

<div class="section abstract"><div class="htmlview paragraph">Slip or relative rotation between the tire and rim is a significant concern for vehicle operation and wheel manufacturing since it leads to wheel imbalance and vibration as well as power losses. A slip situation typically occurs due to improper bead lubrication and mounting, irregularities in the bead seat, and extreme loading conditions with high torques and low tire pressures. Currently, there are relatively few published studies on the tire-rim interface, and they mainly focus on topics such as the mounting process, load transfer, and friction modelling. This leaves a gap to explore the measurement and variation of gross tire-rim slip under the dynamic conditions of a driven tire. In this paper, a previously developed and validated FEA truck tire model was modified to include a frictional contact surface between the tire and rim, and then the slip ratio between the tire and rim was measured under different operating conditions. The new model’s static behavior was compared to the previously validated model with the fixed tire-rim connection, then the model parameters such as vertical load, inflation pressure, drawbar load, longitudinal wheel speed, and tire-rim friction were varied and their effects on the tire-rim slip of the driven truck tire were investigated. It was discovered that factors affecting the torque transmitted through the wheel, including the tire-rim friction, vertical load, and inflation pressure, had the most significant effect, while the longitudinal wheel speed had a minimal effect on the tire-rim slip. The findings of this research work will be useful for determining the tire-rim slip under various operating conditions.</div></div>

고속철도차량용 차륜 불평형에 의한 동적 거동 특성 연구

회전체는 질량 중심선이 축의 기하학적 중심선과 일치하지 않을 때 불평형이 발생한다. 윤축은 두 개의 차륜과 한 개의 차축으로 조립되어 철도차량을 주행시키는 회전체 역할을 하고, 차륜 재질의 불균일, 마모, 윤축 조립과정의 오차 등으로 인해 불평형이 발생할 수 있다. 또한 윤축은 축의 직경이 가늘고 고속으로 회전함으로 불평형 질량에 의한 진동의 영향이 더욱 두드러지게 나타나고 이로 인해 철도차량 고속 주행 시 주행안전성 및 주행거동에 영향을 미칠 수 있다. 그러므로 본 연구에서는 차륜 불평형이 고속철도차량의 동적 거동에 미치는 영향을 철도차량 다물체 동역학 해석 도구인 VI-Rail를 이용하여 해석을 수행하였다. 해석결과에서 차륜 불평형량이 증가할수록 철도차량 대차의 임계속도가 감소됨을 확인할 수 있었고, 차륜 불평형량이 주행 중 차량동적거동 악영향을 미침으로 고속주행에서는 반드시 차륜 불평형량에 대한 관리가 필요함을 확인할 수 있었다. 또한 이 연구로 차륜 불평형량의 정적 및 동적 관리 필요성을 국내 철도차량 운영기관에 제시하였다. This occurs when the unbalanced rotating body is inconsistent with the mass center line axis geometric center line. Wheelsets are assembled by a single axle with two wheels and a rotating body of a running railway vehicle. Owing to non-uniformity of the wheel material, the wear, and error of the wheel and axle assembly may cause an imbalance. Wheelsets will suffer the effects of vibrations due to the unbalanced mass, which becomes more pronounced due to the thin and high-speed rotation compared to the shaft diameter This can affect the driving safety and the running behavior of a rail car during high-speed running. Therefore, this study examined this unbalanced wheel using a railway vehicle multibody dynamics analysis tool to assess the impact of the dynamic VI-Rail movement of high-speed railway vehicles. Increasing the extent of wheel imbalance on the analysis confirmed that the critical speed of a railway vehicle bogie is reduced and the high-speed traveling dropped below the vehicle dynamic behaviour. Therefore, the adverse effects of the amount of a wheel imbalance on travel highlight the need for management of wheel imbalances. In addition, the static and dynamic management needs of a wheel imbalance need to be presented to the national rail vehicles operating agency.

Modeling vibrations of manual grinding machine ИП2014П

Mathematical models of the manual grinding machine (MGM) ИП2014П were given and their analysis in idling and working stroke conditions was performed. An adequacy of the presented mathemati­cal models with the real modeling object was achieved. The results of the analysis of existing standard requirements to unbalanced masses of abrasive wheels based on the compliance with requirements to local vibrations, affecting the operator were provided. By modeling vibrations on the left handle of the MGM in the idling conditions, it was found that the wheel imbalance is equal to 0.004 mкр on its radius, i. e., at its maximum permissible value according to GOST 23182-78 does not guarantee fulfilling sanitary standards. An assessment of the vibration safety of the MGM in idling and working stroke conditions with abrasive wheels made using tradi­tional shaping technology was carried out. It was found that with the existing ПП 150х25х32 wheel shaping technology, maximum error of the wheel shape and placing it on the spindle of the MGM lead to the vibration excitation on the left handle of the MGM in the idling conditions in the range of (33÷49) mm/s, and (26÷56) mm/s in the working stroke conditions, which is on average 1.6 times higher than sanitary standards.

3211 高速鉄道車両用腰掛の複合的振動の解析 : MBD詳細モデル構築を目指して(OS1-2 振動の低減,OS1 交通・物流システムの高速化、利便性、快適性の向上,オーガナイズド・セッション(OS))

In recent years, the technology development in high speed railway vehicle that aims for further service improvement, ride comfort improvement and reduction of energy consumption has been continued. Therefore, design of lightweight high speed railway vehicle seat that provides good ride comfort to passenger is needed. In previous studies, it is revealed that the high frequency vibrations around 30-40Hz are occurred due to the wheel imbalance and they have a harmful influence on ride comfort. For these reasons, the objective of this study is to analyze vibration mechanism of the seat to obtain the guideline to design the seat which can reduce the high frequency vibration. Therefore, this paper describes the results of vibration experiment using two-seater seat and shaking to clarify the vibration characteristics of the seat.

마찰을 고려한 노즈 랜딩기어의 비선형 쉬미 해석

쉬미는 항공기의 이착륙 시 랜딩기어가 주행도중 측방향 및 조향방향의 진동이 발생하는 현상이다. 쉬미 현상은 스트럿의 낮은 강성, 랜딩기어 내부의 유격, 휠의 불균형이나 마모된 부품 등으로 인해 발생하며, 항공기의 안정성을 저하시킨다. 본 연구는 소형항공기의 쉬미 안정성 검토를 위해 수행되었다. 수치해석을 위하여 소형항공기의 전방 착륙장치를 선형시스템으로 모델링하고 상태방정식을 수립하였다. 근궤적 기법을 이용한 주파수 영역 해석과 4차 Runge-Kutta 방법을 이용한 시간영역 해석을 통해 쉬미 현상을 예측하였고 주요 변수의 설계범위를 검토하였다. 현 착륙장치는 와셔의 압축력을 이용하여 조향 방향 마찰을 가함으로써 쉬미현상을 저감하는 기법을 채택하고 있으므로 마찰을 기술함수를 이용하여 선형화시키고 상태방정식에 적용하여 해석을 수행함으로써 쉬미의 발생이 저감되는 결과를 확인하였다. Shimmy is a self-excited vibration in lateral and torsional directions of a landing gear during either the take-off or landing. It is caused by a couple of conditions such as a low torsional stiffness of the strut, a free-play in the landing gear, a wheel imbalance, or worn parts, and it may make the aircraft unstable. This study was performed for an analysis of the shimmy stability on a small aircraft. A nose landing gear was modeled as a linear system and characterized by state-equations which were used to analyze the stability both in the frequency and time-domain for predicting whether the shimmy occurs and investigating a good design range of the important parameters. The root-locus method and the 4th Runge-Kutta method were used for each analysis. Because the present system has a simple mechanism using a friction to reinforce the stability, the friction, a non-linear factor, was linearized by a describing function and considered in the analysis and observed the result of the instability reduction.

Vibration analysis of rail grinding using a twin-wheel grinder

Grinding is the final process of machining a rail. Conventionally, the rail’s surfaces are ground by a single-wheel grinder. The vibrations caused by the grinding process can greatly influence the final surface roughness and dimensional accuracy of the rail. This research investigates performance achieved by using two grinding wheels simultaneously and symmetrically on two opposite surfaces of a rail. In practical terms, the feed force from the two grinding wheels cannot be aligned perfectly, and the imbalance and/or imperfect roundness of the grinding wheels will certainly result in vibrations during the grinding process. This study applies an impedance method to determine rail vibration and the grinding instability, such as chatter caused by feed force misalignment and grinding wheel imbalance. When compared to conventional single-wheel grinding, the results indicate twin-wheel grinding reduces rail vibration, leading to low incidence of grinding chatter and better grinding performance. However, feed force misalignment between the two grinding wheels can lead to increased chatter, and both resonance and chatter may occur at lower grinding speeds as feed force misalignment increases. Results also show that feed force misalignment has a greater effect on rail vibration and chatter than imbalance asynchronization between the two grinding wheels.

Influence of controlled tool orientation on pattern formation and waviness in surface grinding

The surface of ground components can exhibit quality impairments which are attributed to grinding wheel irregularities. A remaining grinding wheel imbalance or a non-uniform grinding wheel topography results in a radial run-out which strongly affects the generated surface. By measuring and adjusting the phase-shift of the grinding wheel orientation during consecutive grinding passes, the resulting workpiece surfaces can significantly be improved. Experimental investigations show a strong effect of the phase-shift on the waviness profile and the pattern formation, as the pattern wave length coincides with the tangential feed. Setting the phase-shift directly affects the engagement conditions like the contact stiffness, remarkably influencing the dynamic process behaviour. The amplitudes of the normal force at rotational frequency have a strong effect on the workpiece surface, which can be influenced by a variation of the phase-shift. Constancy of table oscillating period will further increase due to faster machine control hardware, making longer periods of constant phase-shifts more likely to occur. As this parameter is mostly uncontrolled, it can cause intermittent grinding errors.

유격을 고려한 노즈 랜딩기어의 비선형 쉬미 해석

In this paper, we studied the shimmy phenomena of an aircraft nose landing gear considering free-play. Shimmy is a self-excited vibration in lateral and torsional directions of a landing gear during either the take-off or landing. This phenomena is caused by a couple of conditions such as low torsional stiffness of the strut, friction and free-play in the gear, wheel imbalance, or worn parts, and it may make an aircraft unstable. Free-play non-linearity is linearized by the described function for a stability analysis in a frequency domain, and time marching is performed using the fourth-order Runge-Kutta method. We performed the numerical simulation of the nose landing gear shimmy and investigated its linear and nonlinear characteristics. From the numerical results, we found limit-cycle-oscillations at the speed under linear shimmy speed for the case considering free-play and it can be concluded that the shimmy stability can be decreased by free-play.

Investigation of Dynamic Performance of Super-High Speed CBN Grinding Wheel

The dynamic performance of the grinding wheel system is one of the key factors to affect the super-high speed grinding process The excessive centrifugal stress acted on the wheel body can make the wheel rupture due to the super-high rotary speed of the wheel. And the alternating centrifugal force caused by the wheel imbalance can not only make the spindle and bearings vibration and failure, but also lower the machining precision and the wheel life, as well as make against the safety. In this paper, the centrifugal stress of the high speed grinding wheel and its effect on machining process were analyzed by means of finite element analysis and simulation. The alternating centrifugal force and its effect on the wheel spindle system were investigated. Furthermore, the balance precision of super high speed grinding wheel and system was discussed for achieving the high precision, safety and efficiency machining process.

Lateral Response of Nonlinear Nose Wheel Landing Gear Models with Torsional Free-play

Nose-wheel landing gears can, under certain conditions, exhibit instability in lateral dynamics, causing divergent coupled lateral flexural and torsional oscillations called shimmy. The stability of the system depends on the dynamic characteristics of the gear and tires, nonlinearities in the system, and vibratory modes of the vehicle as a whole, as well as the degree of coupling that exists between them. Shimmy may be caused by a number of conditions such as low torsional stiffness of the strut, free play in the gear, wheel imbalance, or worn parts. Free play in the steering degree of freedom has the potential to significantly reduce the divergent shimmy velocity. Nonlinear behavior of landing gear makes the evaluation of the shimmy phenomenon more complex and its prediction more difficult. This work presents a study of the shimmy instability of a three-degree-of-freedom simplified nose-wheel landing gear model with linear flexible tire model and nonlinearities arising out of torsional free play. Response results are presented for a typical range of values of various problem parameters. Numerical studies bring out several interesting features of the shimmy and its dependence on free play.

New approach to semi-active vibration isolation to improve the pointing performance ofobservation satellites

A momentum-wheel installed to provide attitude-control torque actually producesundesirable force or torque disturbances owing to wheel imbalance and imperfection of theball-bearings. To improve the pointing performance of observation satellites, a vibrationisolator is used to isolate observation devices from these disturbances. This paper comparesthree types of semi-active isolators that consist of a piezoelectric material and aswitch-controlled passive circuit. Since this isolation is implemented by controlling a circuitswitch no external energy is supplied to the system, and so the system is stable even whena malfunction occurs in control. We propose a simple but effective isolation method thatneeds to know only one velocity value instead of the full state of the system. Numericalsimulations with a simple model of an observation satellite demonstrated that the proposedisolator works well to isolate an observation device from disturbances caused by themomentum-wheel, without causing any degradation in the attitude control of satellites.

Some Problems Connected With Balancing of Grinding Wheels

In most publications, the unanimous opinion prevails that an increase of grinding machine vibration as well as deterioration of workpiece quality are observed when the grinding wheel imbalance is on the increase. However, various data on the qualitative influence of wheel imbalance on the realization of the grinding process occur. In this paper a theoretical explanation of the influence of wheel imbalance on the dynamics of grinding, as well as the course and results of investigations proving theoretical considerations, are described. The widely known opinion is that only one-plane balancing of the grinding wheel is sufficient. Also the majority of wheel balancing equipment has the capability of only one-plane imbalance corrections. The purpose of the present paper is to prove that the wheels used in precision grinding always should be balanced in two planes.