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A seal ring of PEEK material was developed and shown to withstand high pressure and high shaft velocity. This was made possible by cooling the ring material using leakage through an engineered passage at the cut junction. The cooling effect of leakage rate was modeled thermodynamically, and calculated leakage rates were compared to measured results.

This paper introduces a new simulation test method by using IR analysis which is capable of evaluating the rate of deterioration of VMQ (Silicone) rubber material applied in engine crankshaft seal applications. IR analysis is used to measure the rate of change of the Si-C/Si-0 ratio which indicates the level of deterioration of VMQ material from the hydrolysis of the siloxane bond. Applying the new analysis method, laboratory test conditions could be improved to more closely simulate field conditions.

In the seal ring used for the rotating portion of the automatic transmission, we have developed a seal ring in which the wear of the ring is reduced to 1/10 under PV-value of 12MPa · m/s and equivalent at PV-value of 30MPa·m/s and also the frictional torque of the rotating portion is reduced to 1/2 when compared with the conventional PTFE seal ring. This has been achieved by means of improvement of the oil pocket's shape, size, and the distance between oil pockets equally spaced on the side surface of the seal ring.

Transmission manufactures have been required of performance improvement and miniaturization for the AT (automatic transmission) or CVT (continuously variable transmission) unit from car manufactures. Current unit is composed of Aluminum piston, O-ring (or D-ring) and drift ball. We changed design from O-ring to lip type seal and aluminum piston to high strength steel plate piston in order to miniaturize. On the other hand, we changed drift ball to canceler in order to make faster response. At this time, we selected new lip design and developed high tensile strength ACM to keep as same oil pressure resistance and durability as current O-ring. In addition, we could have lower friction with new design of lip shape.

This study aimed to visualize crack initiation and propagation of rubber at low temperatures. Typical fatigue behavior such as cracking at only the compressed part of rubber products like dustcovers during oscillation tests at ultra-low temperatures have been reported [1]. Rubber products are usually used at temperatures where good rubber elasticity can be obtained. However, in some cases, they are used near glass transition temperatures at which rubber elasticity is poor. Fatigue failures of rubbers generally occur due to existing defects in the rubber material, and rubber tends to fracture easily near glass transition temperatures due to cracking on the surface of the compressed side of the rubber. The observation of the crack initiation process of rubber is difficult at low temperatures because the fracture patterns on rubber disappear when elasticity is recovered at room temperature.

Wear of a seal is greatly dependent on the environmental conditions such as the temperature, the speed, the lubrication condition and the design factors such as the total contact load and the contact width of the seal lip. In this presentation, the authors discuss the phenomenon of abnormal wear of the reciprocating seal for an automatic transmission by investigating from a lubrication theory viewpoint. An improved seal usable in severe conditions was developed as a result of this study and is also explained.

Upgrading of the performance and the durability of bellow boots used to seal constant-velocity joints are essential to seet the demand for higher performance and longer life automobiles. In this discussion about bellows boots for sealing constant-velocity joints, examples and analysis results of bench tests for studying wear and fatigue durability are presented.

The characteristics of the elastomer material and the fiber cloth reinforcing material have been analyzed as related to diaphragm durability. Investigated were diaphragms used for waste gate actuators for controlling the boost pressure of turbochargers. In this presentation, the authors verify the importance of the elastomer material fatigue resistance under high temperatures and the elongation properties, including directional properties of the fiber cloth reinforcing material for the durability of the diaphragms.

The oil strainer is used in an automatic transmission in an effort to trap contaminated particles in the transmission oil and protect the valves and other parts from wearing prematurely. Recently in order to increase the reliability of the transmission, non-woven fabric has been used for the filtering material as it has good contamination trapping ability. On the other hand, oil-passing characteristics decrease by using non-woven fabrics as a filtering material. We analyzed the oil flow in an oil strainer by performing a computer simuration and at the same time obtained good results which were confirmed by visualization.