Tooth Top Research Articles

Numerical Determination of Cutting Parameters for the Control of Klingelnberg Spiral Bevel Gear Geometry

A numerical method for the contact analysis of uniform tooth height epicyclical spiral bevel gears stemming from the Klingelnberg’s Cyclo-Palloid System is proposed. The analysis is based on simultaneous generations of gear surfaces and contact simulation. A theoretical contact identification program has been developed. Conjugated tooth contact is examined. Longitudinal settings of contact patterns or contact across the surfaces from tooth root to tooth top were obtained as a function of machine-settings. The influences of each cutting parameter were isolated and were discussed.

1104 絞りカップを用いた平歯車の試作 : 分流鍛造法による充填率の向上と成形圧力の低減

It was proposed that a production method in which a spur gear was made from the drawn cup by plastic working. This forming method consists of four processes, namely drawing, re-striking, ironing and compressing process. However, the forming of steel gears isn't suitable for the actual production because the forming pressure in the compressing process is too high. And, filling ratio is not also enough. So, It is examined to reduce forming pressure and to improve filling ratio by two types of the divided flow forging method. It is found that divided flow methods be able to improve of filling ratio and to reduce of forming pressure. A deformation mechanism by the FEM simulation is very similar to the experimental result, and it can estimate state of filling up in the tooth top and forming pressure.

Description of five new species of Exogoninae Rioja, 1925 (Polychaeta: Syllidae) associated with the stony coral Mussismilia hispida (Verrill, 1868) in Saõ Paulo State, Brazil

Coral heads of Mussismilia hispida were collected at two islands off the coast of Sa~o Paulo, south-eastern Brazil. Analysis of the syllids associated with these coral heads led to the identification of three new species of Sphaerosyllis: S. isabellae, S. brasiliensis and S. mussismiliaicola, and two of Grubeosyllis: G. breviarticulata and G. longiarticulata, descriptions of which are here presented. Sphaerosyllis isabellae n. sp. is characterized by bulbous antennae, and articulated tentacular and dorsal cirri, with an elongate proximal part and a retractile globular tip, palps densely papillated and blades of compound chaetae very short, nearly without dorsoventral gradation in length; S. brasiliensis n. sp. has a densely papillated body, small and clavate dorsal cirri, and antennae, and a strong dorsoventral gradation in size of the blades of compound chaetae; S. mussismiliaicola n. sp. is characterized by long dorsal cirri and compound chaetae, blades of which are minutely bidentate, with a long spine at the top of the proximal tooth. Grubeosyllis breviarticulata n. sp. is characterized by having long dorsal cirri and short-bladed compound chaetae, while G. longiarticulata n. sp. has compound chaetae with very long bidentate blades. The differences between these new species and those most similar in the two genera are discussed, and a key to all these species is given.

Wear-resisting low noise chain

A chain capable of diminishing noise and wear occurring at the time of engagement of the chain with a sprocket is provided. At least a portion of an inner surface of each inner plate, which comes into opposition to a side face of a tooth top of the sprocket at the time of engagement of the chain with the sprocket, is chamfered in a shape conforming to the contour of a side tooth form of the sprocket tooth top. Since a chamfered portion of an inner surface of each inner plate has a shape conforming to the contour of a side tooth form of a sprocket tooth top, the chamfered portion and the sprocket tooth top come into contact with each other smoothly in a state of face-to-face contact, so that the level of noise generated upon engagement of the chain with the sprocket can be reduced and it is possible to suppress the wear of the inner surface of the inner plate and that of the tooth top of the sprocket.

An Improved Model for Saturated Salient Pole Synchronous Motors

An improved model for the transient analysis of saturated salient pole synchronous motors is presented. With the aid of saturation factors obtained by means of test or finite elements, Park's equations for a synchronous machine are modified to independently account for the saturation of the d and q-axis magnetizing flux linkages in the region of the stator teeth and rotor pole fact as well as saturation of the total flux linking the stator core. The model is used to calculate the starting performance for a direct on line start as well as the transient performance during a load change. Both transients are correlated with both test results and the results predicted by a traditional model employing only d-axis main flux saturation. The new model demonstrates an improvement over more traditional models indicating that an appropriate representation of the main flux and core saturation effects are important for synchronous machine analysis. Figure 1 shows the complete equivalent d-q circuit model developed in the full paper. The inductance Lsa represents the reluctance of flux lines which are primarily in air. Lsc represents the magnetic reluctance of the stator core, Lsb accounts for the leakage inductances which are primarily iron related, i.e., slot leakage, tooth top and harmonic leakage. Lmd, Lmq account for the magnetizing flux linkages representing the MMF drop in the stator tooth top and field pole. In general, all of these inductances except Lsa can saturate.

Lead in teeth: The influence of the tooth type and the sample within a tooth on lead levels

Different sections of permanent teeth have been sampled and the lead levels estimated using carbon furnace AAS. Very high levels of lead (500–3400 μg g −1) and other trace metals (Cd, Cu, Fe and Zn) occur on the surface of the teeth, falling off rapidly a few micrometres into the teeth. Lead levels in the bulk enamel of incisors vary depending on the position within the tooth, the highest values occur on the lingual side near the gums and the lowest levels on the labial side near the tooth top. The ratio of the concentration of lead in enamel to dentine and to circumpulpal dentine was found to be 1:2:6, and within the dentine the lead levels were highest in the root dentine. The root dentine in the permanent teeth of eight, near complete or representative, sets of teeth was analysed for lead. The ratio ([Pb] tooth/[Pb] total set) decreased in the order: first molars > central incisors > lateral incisors > canines > premolars > second molars > third molars. This order inversely correlates with the age of formation or eruption of the teeth, i.e. the older teeth have the highest levels of lead in the dentine. Dentine appears to be the best material to use to estimate lead, particularly in relation to the integrated lead intake of a person. Dentine lead was determined in a small sample of deciduous teeth obtained from children living in rural areas. The levels were found to be slightly less than for children living in new housing urban areas and significantly less than for children living in older houses of urban areas.