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Technical Paper

Valve Spring with High Fatigue Resistance for Automotive Engine

Recently, SiCr clean steel wire for springs on automotive engine valves has been developed. This report describes the characteristics of valve springs subjected to a new manufacturing process using SiCr clean steel wire. The process developed by the authors is as follows: First, form a helical spring with SiCr clean steel wire. Next, quench using the distortion preventing technic --Marquenching--. Temper at a temperature lower than the conventional temperature. Shot peen to the surface layer of the spring. And lastly, polish electrolytically to remove micro surface defects formed through shot peening. Using this new manufacturing process, a valve spring with high fatigue resistance can be produced. At the test stress of 588MPa(τm)±490MPa (τa), the number of cycles to fracture was above 100 million, while the number of cycles to fracture was 4 million using the conventional process with the SiCr clean steel which has the best fatigue resistance for commercial use.
Technical Paper

Rotary Car Air Conditioner Made with P/M Al-Si Wrought Alloys

We have developed new P/M Al-Si wrought alloys having high strength and high wear resistance for use in the rotors and vanes of rotary car air conditioners. In addition, combined with the development of near-net-shape extrusion technologies, through a joint project with Diesel Kiki Co.,Ltd., we have succeeded in the world's first mass production of rotors made of P/M aluminum wrought alloy. In this paper, the properties and production technology of vanes and rotors made with new P/M Al-Si wrought alloys are presented.
Technical Paper

Lubrication Pump Made of Rapidly Solidified Aluminum Alloy for High Performance Engine

An internal gear-type pump has advantages compared with an external involute gear-type pump, for example, higher mechanical or volumetric efficiency, considerable reduction of weight and dimension in the oil-pump system[1]. This paper presents characteristics of the internal gear type rotors with a modified trochoidal profile in the oil-pump system, and new P/M(Powder Metallurgy) aluminum alloys which satisfy required wear properties as the lubrication oil-pump rotors. Also, the advantage of high volumetric efficiency and discharge performance and excellent properties of the oil-pump rotor with a modified trochoid profile were combined with a R/S (Rapidly Solidified) aluminum alloy in the scavenging pump for racing car engine. Good results without wear or damage after an actual race are also reported.
Technical Paper

High-Speed Machining of Titanium by New PCD Tools

The paper deals with the end-milling machinability of α-β titanium alloy (Ti-6AI-4V alloy) by new PCD (Polycrystal-line Diamond) cutting tools at high cutting speeds in order to develop a new technology for a high productivity titanium finishing. The main focus of this paper is on investigating the relationships among cutting conditions, PCD tool materials, and tool wear. It was found that the edge engagement time of cutting tools with titanium workpiece has a great effect on PCD tool wear. Compared to cemented carbide tools, PCD tools have a longer tool life, especially at higher cutting speeds. The geometric shape of cutting edges and tool material greatly influences the performance of PCD tools in cutting titanium alloy.
Technical Paper

Diesel Particulate Filter Made of Porous Metal

A diesel particulate filter (DPF) using porous metal for a filter, due to its high thermal conductivity, and a radiation heater for a regeneration device, due to its uniform distribution of temperature, has been developed. When high trapping efficiency is required, filter thickness should be increased. However, the thicker filter has a problem of low regeneration efficiency caused by the declination of temperature in the direction of thickness in the filter. In order to improve regeneration efficiency, a filter-heater structure which achieves uniform distribution of temperature was designed by using computer simulation and confirmed good regeneration efficiency of this structure in the experiment.
Technical Paper

Development of a Method to Predict Fatigue Failure Life of Junction Block Bracket Using CAE

With the rapid advances in electronic control within automobiles, the junction block (J/B), primarily used for electrical transmission and electrical wiring, has begun to house electronic control units. It is evolving into an active component with smart functions that also controls vehicle devices, at the core of the wiring harness. We have developed a method using CAE to predict the fatigue failure life of J/B brackets for use as a design-assist tool in the early stage of J/B development. Failure of J/B brackets starts with the repetitive stress generated in the brackets during resonance. This stress is maximum at primary natural vibration which is the lowest frequency during resonance. By accurately estimating the above-mentioned stresses using CAE, we established a method to determine the number of vibrations at which fatigue failure of the J/B bracket would occur (fatigue failure life) from the fatigue failure life characteristics of the material.
Journal Article

Development of High Strength Aluminum Wires for Low-Voltage Automotive Wiring Harnesses

The weight of wire harnesses increases with the growing number of systems used in the vehicle in recent years. For the purpose of reducing the weight of wire harnesses, aluminum instead of the conventional copper is getting popular as a wire conductor. The conventional Al wire, however, is not able to be used for small gauge wires such as the sizes of 0.35mm2 and 0.5mm2 and wires used in the engine compartment due to its insufficient conductor strength. For this reason, we tried to develop a stronger aluminum alloy that has conductor strength equivalent to or stronger than that of copper. For the first time in the industry, we have successfully developed a high-strength aluminum alloy wire. Starting with the application of 0.35mm2 wire for engine wire harnesses, we began mass production in April 2015. This paper reports the development of high-strength aluminum alloy that can be used for small gauge wires and wires used in the engine compartment.
Journal Article

Development of Aluminum Wire for Low-Voltage Automotive Wiring Harnesses

From the viewpoint of reducing the environmental impacts by automobile emission, improving fuel efficiency is essential. That is why automobiles need to be lightened. However, more and more electrical systems have been necessary in an automobile to ensure safety and comfort. With the increase in the number of electrical systems, the weight of Electrical Distribution System (EDS) also has become increased. In order to reduce the weight of EDS, it was decided to evaluate a change of material from copper to aluminum. In fact, aluminum wires have been used for high-voltage wires, but they have almost never been used for low-voltage wires. SUMITOMO ELECTRIC GROUP developed an aluminum wire that is available for low-voltage wire harnesses and started mass production of the wire from October 2010. In this paper, I'm reporting mainly on our development of a new aluminum alloy that can be used for aluminum wires.