Search Results

The demand for quieter vehicle interiors increases year after year. The dynamic force transmission of rolling tires from the road surface to the spindles is a critical factor in vehicle interior noise. We investigated the dynamic force transmission of a rolling tire as it relates to reducing vehicle interior noise. A test with a tire rolling over a cleat was conducted in order to measure the road forces and the spindle forces. The transfer function of the rolling tire was identified from the experimental results by applying multi dimensional spectral analysis. In addition, Computer Aided Engineering (CAE) technology has advanced recently. This enables prediction of spindle forces early in the design stage. One of the most important issues in predicting spindle forces accurately is to clarify the distribution of road forces. This paper also describes the distribution of the dynamic road forces of the rolling tire.

Current simulation of Noise, Vibration and Harshness (NVH) using Computer Aided Engineering (CAE) often uses a large DOF and detailed finite element model along with improvement of CAE technology and computational performance. By using a detailed model, predictions of precise vibration characteristics become possible. However, the number of eigenmodes in the target frequency range increases and engineers require a lot of time to examine eigenmodes and establish countermeasures. In this paper, a practical method of efficient and effective analysis by classifying target eigenmodes into a small number of groups is proposed. The classification is executed based on the relation between the dynamic characteristics of the entire automotive body structure and substructures.

Dual mass flywheel (DMF) is a well-known isolation system for vehicle drivetrain. DMF has two typical elastic energy storage systems: long travel arc springs and in-series spring units (including two or more springs) and sliding shoes connected in series. DMF has such complex nonlinear characteristics as torque-dependent torsional stiffness and rotational speed-dependent hysteresis friction due to its dependency of centrifugal force that is applied to components and radial force of springs. Because of this complexity, sub-harmonic vibration (SHV) may occur under certain circumstances, such as under light-load and high-rotational conditions. In general, since SHV’s frequency is 1/2 or 1/3 of the engine’s combustion frequency and may cause human discomfort, DMF must be designed robust against such nonlinear vibration. In this paper to reduce the SHV occurrence and to show a more robust design indicator, the SHV causing the mechanism is researched by testing and 1D CAE modeling.