Wheel Stiffness Research Articles

A General Approach for Determining Dynamic Forces in Spur Gears

A model is presented taking into account off line-of-action, non-linear wheel stiffness by using the finite element method, and elasticity coupling between the gear teeth. The contact points are determined by searching the common normal using the undeformed, but otherwise true theoretical, tooth shapes where the teeth have a tip rounding to prevent contact singularity in off line-of-action points. A comparative study is included, which shows the important influence of the elastic coupling and off line-of-action.

Dynamics of the Mechanical Levitation Control System for Maglev Transport Vehicle (Effect of Guide Wheel Stiffness and Dead Zone Element)

This paper describes the effect on ride quality and levitation performance of the guide wheel stiffness and the dead zone element of the permanent magnetic suspension system with the mechanical air gap controller. A vehicle dynamic model with the guide wheel stiffness is constructed and the stability criteria for the levitation is derived. The relation between the dynamic characteristics of the vehicle and control lever ratio is analyzed. Seventeen DOF full model simulation results, where nonlinear characteristics of magnet and primary spring are also considered, indicate that the levitation performance of the vehicle is largely affected by the dead zone in the mechanical air gap controller and that the deterioration of the levitation performance can be suppressed by a large control lever ratio.

Influence of Guideway Surface Roughness on a Magnetically Levitated Vehicle with Mechanical Levitation Control. 3rd Report, The Influence of Guide Wheel Stiffness and Dead Zone Element of the Controller.

A theoretical analysis and a simulation study on the dynamic characteristics of a Maglev transport vehicle with a mechanical levitation control system are performed. In this paper, the effect of the guide wheel stiffness and the dead zone element of the controller, which are expected to exert a large influence on vehicle levitation performance and ride quality, is described. After the construction of the vehicle dynamic model with the guide wheel stiffness, the stability criteria for the levitation are derived. The relationship between the dynamic characteristics of the vehicle and control lever ratio is analyzed. The simulation is carried out to confirm the obtained results by using the 17 DOF full model that includes pitching and rolling motion of the vehicle. The simulation results show that a low control lever ratio causes a sudden deterioration of levitation performance if there is a dead zone in the controller, and that a suitable control lever ratio which is unaffected by the dead zone is proposed.

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.

Biomechanics of liver injury by steering wheel loading.

Abdominal injury induced by steering wheel contact at a velocity of 32 km/hr was investigated using anesthetized swine as the surrogate on a Hyge sled. The lower rim of the wheel was positioned 5 cm below the xyphoid. By varying wheel stiffness, wheel orientation, and column angle, resultant abdominal injury ranged from fatal or critical to minor or none. Wheel stiffness was found to be the primary determinant of abdominal injury severity. The mechanism of abdominal injury was identified to be the rim impacting the abdomen and exceeding a combined velocity and compression sensitive tolerance limit. Abdominal injury occurred within the initial 15 ms of wheel contact before whole body movement of the surrogate of column compression, which were initiated by hub contact with the thorax. The severity of abdominal injury correlated with the peak viscous response which can be represented by the product of the instantaneous velocity of abdominal deformation and abdominal compression. It did not correlate with spinal acceleration.

プランジ研削における被削材再生びびり振動に関する理論的解析

A work regenerative chatter in plunge grinding is theoretically studied in this paper. A dynamic grinding force due to the penetrating volocity is derived from a simple basis of a constant volumetric grinding energy theorem for the work material. The contact behaviour between the surfaces of the grinding wheel and work is also included in the analysis and it is shown that each contact stiffness of the grinding wheel and work should be separately treated in the vibration system in plunge grinding. A new block diagram for the regenerative chatter in plunge grinding is introduced and the critical conditions for the chatter vibrations are discussed. The results obtained are as follows. The effects of a number of the grinding variables such as the structural dynamic stiffness, damping coefficient, the natural frequency, the volumetric grinding energy of the material, the plunge velocity, the diameter of the work and wheel, grinding width and the contact stiffness of the wheel and work, on the stability of the chatter are all calculated. The effects of the structural stiffness and the grinding width on the chatter are much different from the results expected in other investigations given by many researchers. The structural stiffness has only small effect on stabilizing the chatter at relatively large grinding width. The large grinding width may also cause to suppress the chatter.