Deformation Of Wheel Research Articles

Effect of Wheel Elasticity on Grinding Stability

Grinding stability was analyzed concerned with contact deformation and contact stiffness of wheels. Elastic deformations of the grinding wheel were measured with inductance sensors. Dynamic grinding system model was set up. Relation between contact stiffness and chatter growing index was analyzed. Chatter suppression experiments with variable grinding speeds were carried out. When wheel is in contact with a workpiece, contact deformation can occur. The contact stiffness of grinding wheel is a variable. The relation between chatter growing index and contact stiffness is an increasing function. Chatter growing index can be decreased by lowering contact stiffness of wheel. The grinding system stability will be improved with variable grinding speed.

Interrelation between various mathematical models of the deformation of elastic wheels

Simulation of the rheological properties of elastic wheels by the Volterra integral equations of the second kind with the Koltunov kernel of the nonlinear hereditary theory of viscoelasticity and by the differential equations that under certain conditions approximately replace the adopted integral equations is suggested. The interrelationship between two different types of mathematical models of the deformation of elastic wheels is shown: without account for the time factor and with account for this factor, as well as of the rheological models: integral and differential equations. For some elastic wheels the parameters of the suggested governing equations have been found from experimental data.

Near surface deformation of rails and wheels in a curve and during acceleration and braking

A hierarchical concept for describing the rolling/sliding contact of a wheel on a rail is proposed, which is developed to model the near surface deformation of the contacting partners depending on the vehicle system dynamics. In principal the vehicle dynamics simulation delivers the input for a static finite element model for the elastic-plastic rolling/sliding contact investigation. To include also more realistic rough surfaces in the calculations, which is absolutely necessary to predict the highly deformed surface layer as observed in wheels and rails, a further refinement of the mesh is necessary and performed. The output values of the static finite element model are now boundary conditions for the finite element micro-model. The results of this micro-model correspond well with the micro-structural investigations of wheel and rail surfaces.

1531 トレーラディスクホイールにおけるボルトの緩みと軸直角力の集中(J07-2 締結・接合部の力学・プロセスと信頼性評価(2) 締結・接合,ジョイントセッション,21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

Loosening of the wheel bolts may be the cause of accidents where the wheel falls off while the trailer is running. When the transverse force of wheel bolts exceeds a certain proportion of the bolt shaft force, the wheel nut begins to loosen. Loosening of a wheel bolt may influence on the deformation of wheel and the transverse forces of other wheel bolts increase, and the bolts may also loosen. In this report the 3-dimensional deformation of the disk wheels and the transverse forces on the wheel bolt are determined by 3-dimensional numerical analysis. In the result, by loosening of 1 bolt the transverse forces at lower position of wheel increase and the concentration at the upper position of wheel cancel.

2P1-A22 圧電発電によって駆動するセンサ情報送信システム(エコ・ロボティクス・メカトロニクス)

We propose a wireless signal transmitting system by gaining energy from the surroundings. As all of energy needed by this system is gained from the surroundings, there are no necessities for refilling fuel or changing battery. For example, Tire Pressure Monitoring System (TPMS) needs such a maintenance-free sensor system. The system consists of a piezoelectric generator, a capacitor, and a circuit. The circuit watches the capacitor's storage and supplies energy to the transmitter. We made an experiment to gain energy from the deformation of a car wheel with the generator. The energy from the environment is estimated to be about 20mW. This estimation shows that we can drive a transmitter for 1 second after 7 second's charge. We were also able to drive the transmitter in another environment from which the generator gains a little energy, so this system is available not only on wheel's surface but also in general environments.

Prediction of wheel wear in urban railway transport: comparison of existing models

One of the most important maintenance costs in tramway transport comes from wear of wheel profiles. In the highly competitive railway market, the prediction of wear is then a major concern of the constructors. In this article, we present and compare four models well adapted to tramway conditions, involving contacts on the rolling tread and on the flange with very different sliding and pressure conditions. Moreover, all models can be implemented from the natural outputs of the railway simulation packages classically used in industry for the dynamics design of the vehicles. The first one, proposed by Jendel, is based on the well-known Archard's wear model. Enblom continues Jendel's approach by taking into account the contribution of wheel deformation on the sliding velocity. The last two models, developed by Zobory, and Pearce and Sherratt, determine the wear from the energy dissipation in the contact area. The models are first compared on a theoretical basis and, for that purpose, are rewritten in a common form. Two cases are distinguished: mild wear as arising on the rolling tread and severe wear as arising on the flange. The models are also compared in the practical case of an urban transport vehicle running on circular tracks with different curve radii. Although the models show equivalent trends according to the theoretical study, important discrepancies appear between estimated wear depths. All models are actually dependent on experimental coefficients and it is likely that they were estimated in different conditions. On the other hand, a reasonable agreement can be found in some particular conditions. As an example, Zobory's, Enblom's and Jendel's models are very close to each other in severe wear conditions. This work shows that a general and reliable model could probably be developed from all positive aspects of the existing ones.

Investigations of silicon wafer grinding using finite element analysis

Silicon wafers are used as substrates to build more than 90% of integrated circuits. One of the manufacturing processes for silicon wafers is grinding. This paper reports the investigations of silicon wafer grinding using Finite Element Analysis (FEA). FEA models are first used to study the effects of process parameters on waviness reduction in the grinding of wire-sawn wafers on a rigid chuck. Then, soft-pad grinding of wire-sawn wafers is modelled using FEA to study the effects of pad properties on waviness reduction. Finally, FEA is used to study the elastic deformation of the grinding wheel, providing an explanation for the central dimples on ground wafers.

Research on NC Point-Grinding of the Curve Based on Normal Tracing

This paper presents a new technology, which is the normal tracing, for NC point-grinding of the curve. The development of the technology is based on the simultaneous three-axis machining. By controlling the superposition between the rotary surface of the grinding wheel and the normal vector of the curve, point contact between them is realized. So grinding just like turning, the abrasive machining of the complex curve is easy to be realized. The main advantage of the technology is the fact that it can not only reduce the deformation of the grinding wheel and simplify the NC programming, but also improve surface quality and profile accuracy. This paper builds the mathematic model of the normal tracing by analyzing the geometric property and the kinematic relationship between the wheel and the work piece. Then the control algorithm of the normal tracing is given and used in a new-type digital curve grinder successfully, MD9040 developed by ourselves.

3-Dimensional Analysis of Deformation of Disk Wheels and Transverse Force of Wheel Bolts

3-Dimensional Analysis of Deformation of Disk Wheels and Transverse Force of Wheel Bolts

Analysis of wheel–rail interaction using FE software

In this article, research into the influence of interacting wheel and rail profiles on the distribution of contact zones and stresses is presented. The influence of contact forces on the deformation of rolling carload wheels and rails, and the influence of this deformation on the redistribution of the contact stresses is also investigated. The quasi-Hertz method as well as a finite element (FE) method were included as basis of mathematical simulation. With these tools, distributions of contact zones for different angles of attack of the wheelsets were defined. The problem was solved in three-dimensions. The offered technique to solve the contact problem has been used for the improvement of operating wheels.

The compensation of geometrical errors on forming grinding

Form grinding produces a surface with a particular profile. In a plug-grinding system, the shaped wheels transfer their profile to the ground work surface. Several factors affect the geometrical errors that occur in grinding, including thermal deformation, the cutting forces of the workpiece and the wear and the plastic deformation of the grinding wheel, owing to the different profile sections of a grinding wheel diameter. This work develops a mathematical model of the thermal deformation and cutting forces by utilizing the thermal bending moment and specified grinding energy proposed in other research. The wear and deformation of a grinding wheel are analyzed using experimental data. The model is formulated using simple contours and the resulting predictions of geometrical errors are compensated for by altering the path of a diamond tool using the CNC controller in the grinding machine. In addition, a series of experiments is carried out on different slopes with box convex and concave profiles. These results demonstrate that the geometrical errors that occur commonly in form grinding can be reduced by more than 70%.

Vibratory Cut-Off Grinding.

In conventional cut-off grinding, the elastic deformation of the grinding wheel is large, and the flatness of the cut-off surface becomes low. Moreover, in the cut-off grinding of carbon steels, the burn mark occurs often on the cut-off surface. In order to improve the flatness of the cut-off surface and to prevent the occurrence of the burn mark, vibratory cut-off grinding is proposed in this study. The workpiece is forced to vibrate in the table feed direction, that is to say, the frequency f is 30 Hz and the amplitude 2 A is from 0.45 to 2.75 mm. In order to clarify the effectiveness of the vibratory cut-off grinding, the grinding performance were experimentally investigated. The main results obtained are as follows: (1) Vibratory cut-off grinding is effective for the improvement of the flatness of the cut-off surface and for the prevention of the burn mark in case of SKH51. (2) In the conventional cut-off grinding of SKH51, the smaller slicing distance causes both the burn mark and the burr. However, both the burn mark and the burr are prevented in the vibratory cut-off grinding. (3) The grinding power in the vibratory cut-off grinding becomes smaller than that in the conven- tional cut-off grinding. (4) The wheel wear volume in the vibratory cut-off grinding of alumina ceramics became smaller than that in the conventional cut-off grinding. However, in case of SKH51 the vibratory cut-off grinding makes the wheel wear volume large. This was caused by the fast maximum work speed Vwmax.

APPROACHES TO PREDICT THE VEHICLE DYNAMICS ON SOFT SOIL

ABSTRACT This paper deals with the dynamic behavior of vehicles, especially on soft ground. Two different ways of simulation are described. One is based on the rigid body simulation program ADAMS, the other approach uses the Finite-Element-Method in conjunction with a dynamic solving algorithm. By the presented simulation results it is pointed out, that on soft soil a self excitation of the wheel exists which is caused by the deformation of the ground. The influence of this effect becomes critical when the second wheel of the vehicle is excited by the left back deformations of the first wheel. Additional measurements, investigating the dynamic influence on the behavior of the soil are used in a third, simple simulation model, based on the rigid wheel approach of BEKKER. The results show that the critical effect of self excitation is reduced by the dynamic damping behavior of the soil.

内部研削における砥石と工作物の熱変形挙動から考察した形状創成機構の研究

In this report in order to make clear the form generation mechanism in the internal plunge grinding process, the thermal deformations of wheel and workpiece are measured with both workpiece width and grinding time. Main conclusions obtained are as follows: (1) In the internal plunge grinding, by contrast to the surface or external grinding, the workpiece surface expands with the thermal deformation in the opposite direction of wheel surface. (2) The ground workpiece profile becomes an extremely concave profile, because the wheel surface expands just like a barrel shape due to the thermal deformation of wheel. (3) In contraction process of the thermal deformation of workpiece the concavity decreases but after grinding the concavity is left as an error of surface profile.

Ｘ線ミラー用気相成長炭化けい素の延性研削

This paper deals with ultra-precision grinding of chemical vapor deposited silicon carbide (CVD-SiC) for high power X-ray mirrors. CVD-SiC samples were ground by a numerically controlled surface grinder with variously-bonded diamond wheels, so as to get smooth surface roughness and high profile accuracy without a polishing process. SD4000-M wheel can grind CVD-SiC samples without fracture on the finished surface that is 3nm Ra in surface roughness and 0.3 μm in profile accuracy. Resinoid bonded wheels can easily get the smoother surface roughness, however, profile accuracy is limited at 0.9 μm due to the wheel deformation. The worn SD2000-M wheel can also get the ductile mode grinding on CVD-SiC samples. The surface fracture rate on ground surface strongly depends upon the grain size of diamond grits as well as the feed and depth of cut.

Effect of technological factors on the deformation of gear wheels in gas carburizing and quenching

1. Quenching deformation (warping) or parts does not depend on the regime and method of quenching alone but also on the kinds and methods of the preceding gas carburizing and heat treatment. To reduce the scatter and mean magnitude of quenching deformation and warping of large disk wheels with splined hole, we recommend accelerated air cooling of forgings and of forged blanks, high tempering (at 620–640°C, 4 h) after rough machining, heating for quenching in a protective atmosphere with subsequent cooling in oil at 150–180°C. 2. In view of the stronger effect of the placing of the parts in carburization on the quenching deformation, this factor has to be regarded as decisive in the choice of the method of immersing the part in oil in quenching. 3. The effect of each investigated factor on deformation (warping) in quenching is judged according to several measured traits. The reliability of such an effect depend on the “sensitivity” of the structural elements (toothed rim, spline grooves in the hole, etc.) to the technological effects of heat treatment and carburization.

ファインセラミックスの鋳鉄ボンドダイヤモンド砥石によるクリープフィード研削機構

Cast iron bonded diamond (FC-D) grinding wheel is now used for ceramics grinding due to its high performance. The grinding mechanism is investigated experimentally by the measurement of grinding force in rather slow wheel speed and the observation of wear behaviours of abrasives. Main results are : (1) The grinding mechanism of the cast iron bonded grinding wheels resembles that of the metal bonded diamond wheel but the wheel deformation is small and drops of abrasives are not so often in FC-D wheel even under the heavy duty grinding, because the wheel stiffness and holding strength of abrasive are both very high. (2) It is possible to use the FC-D grinding wheel under the condition of flat topped abrasives. In this case, though the grinding force becomes higher, the roughness of ground surface is improved and the grinding ratio is high. (3) When the protrusion amount of abrasives from bonding surface is not enough, the sparking phenomena occurs by the direct contact between bond material and ceramics in heavy grinding and this leads to dressing effect.

The mechanism of corrugation phenomenon on rolling surfaces. (2nd report. Analysis of vibration and deformation mechanism).

To analyze the mechanism of corrugation formation caused by plastic deformation in experiment, vibration and elastic-plastic vibration deformation equations are proposed. The variables used in these equations are displacement of wheel, corrugation profile and deformation per one pass of contact. To measure the deformation per one pass, special experiments are made, and the characteristics of these equations are determined. Then. the property of elastic-plastic deformation and vibration of wheel are examined theoretically in rolling contact to determine the cause of corrugations.

ベルト研削加工面に及ぼすと粒切れ刃高さ分布と弾性変位量の影響

A simulation of abrasive belt grinding process was carried out. In abrasive belt grinding, the height distribution of grain cutting edges changes with the advance of grinding time and the elastic deformation of contact wheel is the cause of the displacement of grain cutting edge position. So, the influence of the height distribution and elastic displacement of the grain cutting edges were investigated by the simulation. As a result of that, the mechanism of residual depth of cut and the finished surface roughness were analyzed theoretically in cylindrical plunge grinding. The obtained main results are as follows. (1) Residual depth of cut and finished surface roughness increase as the height distribution of grain cutting edges becomes wide. (2) In the case of using a rubber contact wheel, the displacement of grain cutting edges makes the residual depth of cut increased. But, the increase of effective cutting edges makes the finished surface roughness improved. (3) Residual depth of cut caused by the height distribution and displacement of the grain cutting edges is almost generated at the start of grinding. (4) It was found that there is an optimum rubber hardness of contact wheel.

Problems in Profile Grinding — Angular Plunge Grinding and Surface Grinding

Profiles can be ground using plane and cylindrical grinding techniques, whereby similar problems are encountered in both cases. For example, it is of importance to know whether cylindrical or asymmetrical profiles are to be ground. When grinding asymmetrical profiles axial forces occur, they can constitute a major problem. There will be deformation of the grinding wheel in an axial direction and the ground profile will be inaccurate. Another problem is the variation of surface roughness over the profile for the different dressing conditions and the different plunge angles used in angular plunge grinding. The right dressing conditions and plunge angle must be selected so as to avoid burn or chatter marks on the workpiece. Other problems are also discussed in this paper.