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Some of the frequencies of transmission gear whine noise reach up to several kHz. High-frequency gear whine noise is mostly transmitted by air (airborne); therefore, it is critical to reduce transmission radiation noise. This paper presents how to solve the problem of high-frequency noise in the range of 2.0 - 4.1kHz by experiment using Inverse Boundary Element Method (IBEM) and by computer simulation using Boundary Element Method (BEM).

We have developed injection molding technologies consist of a new high-strength long-glass fiber reinforced polypropylene (PPLGF). They are key technologies of new modular design for substantial reductions of weight and cost, offering integrated functionality. The strength of injection molded parts are three times stronger than that of the conventional material. This technology makes it possible to replace parts from steel stamping and press molded glass-mat reinforced polypropylene. The front end and door modules of Atenza / Mazda6, Demio / Mazda2, RX-8 employs the module carriers using this material, resulting in dramatic weight and cost savings. (Fig. 1)

We have developed injection molding technologies consist of a new high-strength long-glass fiber reinforced polypropylene (PPLGF). They are key technologies of new modular design for substantial reductions of weight and cost, offering integrated functionality. The strength of injection molded parts are three times stronger than that of the conventional material. This technology makes it possible to replace parts from steel stamping and press molded glass-mat reinforced polypropylene. The front end and door modules of Mazda 6 employ the module carriers using this material, resulting in dramatic weight and cost savings.

New press forming method was developed for ensuring shape-accuracy of draw parts with high strength steel sheet(HSS) of very high tensile strength such as 780MPa. In the new method, step drawing method was combined with crash forming method by applying cam flange die structure to drawing dies. Furthermore, the die structure in the method is simple. At the trial press-forming by the model die even with 780MPa high strength steel sheets, the side wall warps in particular were restrained within a specified tolerance, that is ±0.00067[1/mm] of the variation of curvature(Δ 1/ ρ). Now the method is applied to press-forming some automotive body parts, such as front side member, etc.

Reduction of transmission error by gear tooth profile optimization and tuning of gear resonance modes are known as effective methods for gear noise reduction. This paper concentrates on structuring a process for reducing gear noise using the latter method. The procedure comprises a study of gear noise mechanism from transmission error to radiation noise, an application of Steyer's method in gear frequency analysis and implementation of an invented device called “noise reduction ring”. This inexpensive and practical ring reduces gear noise drastically by 10dB, which is predicted by the simulation and verified by the experiment.

Thixomolding® produces net-shape parts from Magnesium alloys in a single step process involving high speed injection molding of semi-solid thixotropic alloys. A description of the process and status of commercial developments will be presented.. The mechanical properties and microstructures of Thixomolded® AZ-91D magnesium materials will be presented. Tensile strengths of semi-solid AZ-91D at both room temperature and elevated temperatures ( 373K, 423K) are compared with die cast AZ-91D. Data on enhanced creep properties of Thixomolded® AZ91-D alloy relative to die cast AZ-91D will be examined with respect to relative changes in microstructural features. Controlling the percent solids in the semi-solid state prior to injection molding can lead to improved creep performance for use in net-shape automotive components.

In the present study, numerical simulation coupling convection and radiation in vehicle was done to analyze the formation of the temperature field under the non-uniform thermal condition. The scaled cabin model of simplified compact car was used and the thermal condition was determined. The fore floor, the top side of the inst. panel, the front window and the ceiling were heat source. The lateral side walls were cooled by the outdoor air and the other surfaces were adiabatic. It is same with the experimental condition presented in Part 5. In order to analyze the individual influence of each heat source, Contribution Ratio of Indoor climate (CRI) index was used. CRI is defined as the ratio of the temperature rise at a point from one individual heat source to the temperature rise under the perfect mixing conditions for the same heat source.