# يعض انواع سيور نقل الحركه.



## عبير عبد الرحمن (19 أغسطس 2009)

_:75::75::75:_

_flat belts_ made from joined hides were first on the scene, however modern flat belts are of composite construction with cord reinforcement. They are particularly suitable for high speeds.




_V-belts_ comprise cord tensile members located at



the pitchline, embedded in a relatively soft matrix which is encased in a wear resistant cover. The wedging action of a V-belt in a pulley groove results in a drive which is more compact than a flat belt drive, but short centre V-belt drives are not conducive to shock absorption.



_Wedge belts_ are narrower and thus lighter than V-belts. Centrifugal effects which reduce belt-pulley contact pressure and hence frictional torque are therefore not so deleterious in wedge belt drives as they are in V-belt drives.



Modern materials allow _cut_ belts to dispense with a separate cover. The belt illustrated also incorporates slots on the underside known as _*cogging*_ which alleviate deleterious bending stresses as the belt is forced to conform to pulley curvature. Cogging should not be confused with the teeth on . . . . 



_Synchous_ _timing belt_ drives are positive rather than friction drives as they rely on gear- like teeth on pulley and belt enabled by modern materials and manufactureing methods. They are mentioned here only for completeness - we shall not examine them further.



If a single V-belt is inadequate for power transmission then multiple belts and corresponding multi- grooved pulleys are necessary - this pulley is equipped with a tapered bush for axle clamping without the stress concentration associated with a key.



The rather extreme short-centre drive on the left illustrates a problem with multiple belts - how to ensure equitable load sharing between flexible belts whose as-manufactured dimensional tolerances are significanty looser than those of machined components .








function. The main load- carrying elements are the tensile members, often in tEach component of a V-belt performs a particular he form of longitudinally stiff rayon cords located near the centroidal axis of the belt's cross-section, embedded in a relatively soft elastomeric matrix whose main purpose is to channel the load from the contacts with the groove sides into the tensile members. 

:20::20::20:منقول


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## AHMAD-1976 (20 أغسطس 2009)

مشكورةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةةة


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## محمود عزت احمد (2 نوفمبر 2009)

*جزاك الله كل خير يااخي*​


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## hmadaalaam (2 نوفمبر 2009)

*حاولت التواصل مع المهندسه عبير لاستشارتها في بعض امور العمل لعلمي بخربتها الواسعه في مجال الهندسه ولكني لم استطيع لان مشاكرتي في المنتدي اقل من 50 ارجو من المهندسه عبير محاول التواصل معي لو هذا ممكن للاستفاده من خبراتها ولها جزيل الشكر*​


هذا اول رد مني علي موضوعك وقد لاقي منكي عدم اهتمام برجاء محاوله التوصال معي عبر الاميل ان امكن احتاج الي مساعده منكي
جزاكي الله خير


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## hmadaalaam (3 نوفمبر 2009)

اسف يا بش مهندسه عبير حاولت الرد عليكي ولكن مشاركاتي لم تتجاوز الخمسين ولا استطيع ارسال رسالتي اليكي


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## mahamadnshat (7 أكتوبر 2012)

شكرااااااااااااا


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