Lhe swelling sets and sliding pulley failure, how to reform?

Lhe swelling sets and sliding pulley failure, how to reform? 2019 - 12 - 17 xiang-dong xin ( The big carbon new material technology co. , LTD. ) Authors for expansion sleeve connection structure modification and redesign, not only meet the requirements of the repair, and successfully applied in production practice, achieved good using effect. Mechanical transmission is widely used in mechanical engineering, mainly refers to the use of mechanical transmission power and motion transmission. Mechanical transmission according to the power transmission way, mainly has the ways such as chain, gear drive and belt drive. Drive belt is in the middle of flexible transmission way, because the belt elastic, and by the friction transmission, therefore it has simple structure, stable transmission, low noise, can buffer vibration absorption, overload will belt on the pulley when sliding, overload protection effect to the other parts, applicable to the center from the advantages of large transmission, the most widely used in mechanical transmission, especially the V belt in the belt transmission, application is very extensive. The pulley and shaft assembly, one of the most common for linkage; But key connection because of the pulley and shaft concentricity is not good, large vibration of the high-speed rotational motion of the so high in some high speed machine tools and precision machine tool often choose lhe swelling on the set of the structure of the form. 1. Problem of my company CGK62 combination milling processing line mill power head ( Diameter of 800 mm) , the power transmission is through the pulley drive with a diameter of 300 mm, the pulley through a tight set of expansion and shaft assembly connection. In the long run, due to the frequent start-stop mill, shaft and assortments of tight, tight set of lhe swelling failure between pulley and sliding, the loss of transmission capacity, its structure is shown in figure 1. Heave tight set of local structure as shown in figure 2, consists of a set of within the opening coat, opening, taut and 12 M8 within the six-party of bolt. Lhe swelling principle: through the bolt to tighten set 2 and tighten set 4 to pull among, due to the tension between set and opening set for two-way contact cone, the opening of the inner sleeve opening clearance, inner diameter is reduced, so that the set of banding on the transmission shaft; Similarly, taut and openings for double cone contact between coat, make opening coat of the opening gap, diameter increases, so that the coat lhe swelling in with round hole. Through the analysis of the structure of lhe swelling sets need to control in the process of manufacturing the following two points: (1) set of two-way taper inside and outside, two tighten the taper sleeve ( A total of four contact) Must be consistent. (2) the inner diameter of the inner sleeve and the outside diameter of the pulley diameter of axle, coat inner fitting clearance of two requirements must be the same. The guarantee of above two parts manufacturing process is very difficult, and there will always be errors in machining, the manufacturing precision increase inevitably increase the cost of manufacture. Especially the inner diameter of the inner sleeve and the outside diameter of the pulley diameter of axle, coat inner fitting clearance in two different causes: (1) inner sleeve and the shaft collar die, pull tight set, but the coat and expansion force of pulley and isn't enough, transmission with coat and slippage between pulley and lose the phenomenon. (2) coats and pulley has been tight, taut sets of the fixed, but the inner sleeve and the shaft banding strength is not enough, when drive slippage between inner sleeve and the shaft and lose the phenomenon. Through careful analysis and field observation lhe swelling of skid grinding condition, found mainly in between coat and pulleys. Through contact manufacturer, need to send the pulley and shaft to factory to repair the belt wheel inner hole after the match to make lhe swelling, so need a month time limit for a project, waiting for the machine tool should be shutdown. 2. Structure to improve the field after discussion decision, lhe swelling jacket structure, use of internal machine to processing and manufacturing. Heave tight set of improved new structure as shown in figure 3. Heave tight set of improved local parts as shown in figure 4, the structure is composed of five parts: the coat pressure and open coat, opening cover, inside casing pressure and 12 six-party bolt M12. Inside and outside the casing pressure LAN respectively with bolt holes on the surface of the pulley ends. Lhe swelling method: first in the belt wheel inner hole into the coat, coat pressure with the bolt and the pulley and fixed, pulley, together with the open coat sleeve on the shaft adjust assembly location ( It can locate the other processing set of implementation) ； In the opening set and insert coat shaft head, with a bolt on the pulley another face pressure inside casing pressure, push the inner sleeve into the coat at the same time; Continue to tighten bolts inside casing pressure LAN, can make the inner sleeve banding on the shaft at the same time let the coat lhe swelling with round hole. Advantages: the unit structure is simple, there is only one interface lhe swelling process of relative sliding, only need to ensure that a taper interface ( The original structure has four taper interface must be the same) ； Without requiring inner sleeve and the shaft, coat the same as the fitting clearance of pulleys; Machining accuracy in addition to the taper fit, no accuracy, simple manufacturing, and processing time. 3. Effect analysis of the improvement of the structure of the lhe swelling sets greatly shorten the time to repair, according to normal to return factory repair, at least 1 months or more, and mill machine tool power head shaft to be removed, repaired and reinstall again. The power head for precision machining power head, back after assembly accuracy will also have change; After transforming don't need to remove the power head shaft, so the accuracy will not change. Use the heave tight set of repair cost is low, normal return to factory maintenance, back and forth transportation cost and upkeep to tens of thousands of yuan. Modified internal processing costs less than 1000 yuan. The part modification after 7 months of continuous use, the effect is very good, has certain promotion value. Source: the metal processing ( Cold working) 12, 2016