The application of the safest anti loose nut in th

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The application of shipilao locknut on CY6102 diesel engine shock absorber

an effective measure to solve the failure of CY6102 diesel engine shock absorber

------ shipilao locknut

song Jindong, 1 Wang Shouyuan, 1 Yu HongZu, 2 zhudajun

(1 Chaoyang Diesel Engine Co., Ltd., 2 Shanghai Dite precision fasteners Co., Ltd.)

abstract: there often happened many cases that dampers of CY6102 sires diesel engines opened and

oil left from the dampers, which caused the engines fail to operate and even damaged engines

By applying Spiralock nut manufactured by Spiralock Corporation (US), and modifying the damper’s

connection structure accordingly, the above failures have been eliminated and the damper’s

performance has been improved, hence improving the engines reliability.

Abstract: the shock absorber of CY6102 diesel engine has failed for many times, such as oil leakage, etc., resulting in the failure of the diesel engine to work normally. Haydale's scientists have been using functional fossil graphene to improve the performance of carbon fiber composites in the aerospace industry, and even lead to the damage of the diesel engine. After adopting the new type of locknut developed and produced by the US company, and making the corresponding improvement design for the connecting structure of the shock absorber, the diesel engine not only eliminates the failure of the shock absorber of the diesel engine under strong vibration, but also improves the shock absorption performance of the shock absorber and improves the reliability of the whole diesel engine

1 preface

cy6102 series diesel engine is a mature product of Dongfeng Chaoyang Diesel Engine Co., Ltd. there are many variants, which are mainly used to provide the power of trucks and large buses, and there are hundreds of types of vehicle applications. One of the shortcomings of this series of diesel engines is that there are often failures such as shock absorber failure and oil leakage, which make the diesel engine unable to operate normally. Many customers have strong complaints and large economic losses. Through the analysis and Research on the failure of shock absorber, oil leakage and other faults, this paper puts forward the use of the new type anti loose nut of Spitzer as a measure to solve the problem, which has been proved to be very effective by practice

2 fault analysis

investigate and analyze the failed shock absorber, and find that the problem is mainly caused by the loose fastening nut of the shock absorber

the shock absorber is fixed through the cone sleeve, the flat key plays a positioning role, and the outer end shaft is fastened with ordinary nuts. Moreover, this type of shock absorber has increased its length according to the requirements of users, making the working conditions more stringent. When the diesel engine is running, the shock absorber bears complex high-frequency reciprocating torsional vibration and violent transverse vibration. These vibrations gradually destroy the pre tightening state of the nut, causing the nut to loosen, so the shock absorber often loosens, oil leakage and other faults. Facing the implementation of China's automobile recall system, the task of solving this defect is very urgent

3 solution

in order to solve the problem of loose fastening nuts of shock absorbers, many improvements have been made in design and technology over the years, but the problem of loose nuts has not been fundamentally solved. These include the use of fine thread, increasing the tightening torque of the nut, coating anti loose glue, adding washers and so on. Some methods also bring new problems of difficult disassembly, resulting in new complaints from customers

the original structure was improved after learning that the new type of spilon nut has excellent anti loosening effect, and that the use of the new type of spilon nut can make the complex locking knot with high efficiency, complete functions, convenient operation and simplified structure

3.1 the locking principle of the shiplock locknut

the shiplock locknut is a new type of anti loose fastener using the internal thread technology of shiplock. The internal thread technology was invented by the American company schpileup, and was first used on the main engine of spacecraft. It has been widely used in automobiles and construction machinery in the United States, and is a mature technology

according to the research of the US company, due to the manufacturing error of the ordinary standard thread, the pre tightening force borne by each tooth shape is very uneven. The force borne on the thread surface of the first and second teeth accounts for more than 70% of the total load, and other teeth are basically in a floating state. The locking force caused by friction is small, so under the condition of vibration load, it is easy to overcome the pre tightening force on the thread contact surface and produce looseness. At the same time, there is friction contact on one side of the screw tooth, and there is a gap on the other side. This is why ordinary threaded fasteners are very easy to loosen when subjected to transverse vibration

the structure of the spilon thread is different from that of the ordinary standard thread. There is a 30 ° wedge surface at the bottom of the internal thread tooth groove. When the nut is matched with the ordinary external thread, the crown of the external thread is tightly wedged into the 30 ° wedge surface of the internal thread root, resulting in a great locking force, and each thread plays a locking role, and the force is uniform. At the same time, the normal force exerted on the wedge-shaped surface forms an included angle of 60 ° with the axis of the bolt, rather than the 30 ° angle of ordinary standard thread. Obviously, the normal force generated by the former is much greater than that of the latter, and the ability of anti loosening friction and anti lateral vibration will inevitably be greatly increased

3.2 improved design scheme and implementation

in order to completely solve the problem of loosening the fastening nut of the shock absorber, the sibilo locknut was introduced into the CY6102 series diesel engine, and the structure of this part was redesigned

the basic idea of the new design is to replace the original ordinary fine tooth nut with the spilon locknut on the condition that the basic size of the original structure remains unchanged. At the same time, remove the taper sleeve and washer used for locking in the original structure to optimize the structure. According to the characteristics and requirements of the spilon locknut, the pitch of the thread and the length of the thread section are correspondingly increased in the design, and the shock absorber is also changed accordingly

due to the cancellation of the taper sleeve, in addition to reducing the processing cost, it can effectively avoid the residual small gap during assembly caused by the processing accuracy and the hidden trouble caused thereby. The length of the key is increased, and the matching relationship between the hub and the shaft is also adjusted. The structure is simpler and more compact than the original one

3.3 requirements for the external thread and assembly of the spilon locknut

when using the spilon locknut, the external thread processing and the assembly of fasteners must pay attention to the following matters:

(1) there must be no decarburization layer during the external thread processing, and the outer diameter of the thread must meet the requirements of the drawing

(2) all parts must be kept clean before assembly

(3) the external thread surface needs to be coated with a little clean engine oil during assembly

(4) the pre tightening torque value is 1200 nm

(5) that is, 811 high nickel cathode material must have mandatory tightening regulations

4 performance and reliability verification

the first is the bench test of the diesel engine. The reliability test of 1000 h bench proves that the anti loosening effect of the Gabriel locknut is very good. At the same time, the vibration damping performance of the shock absorber is tested, and the results show that the vibration damping performance of the shock absorber with the use of the Gabriel locknut is better than the original structure. The torsional vibration characteristics of the original structure, the maximum torsional vibration angle is more than 0.4 degrees; The torsional vibration characteristics of the improved structure have reduced the maximum torsional vibration angle to less than 0.15 degrees, and the torsional vibration performance has been improved to a certain extent, which meets the requirements of the whole machine for torsional vibration control and improves the reliability as a whole

then carry out on-site reliability test. The experiments of refitting the old structure machine with spare parts were carried out respectively, and the user responded well. It has been installed in small batches for several times and put into use on the market. After 30000 kilometers of driving, there were no failures such as the loosening of the shock absorber and oil leakage, which proved that the improvement was successful. Now it is ready to be used on all 6-cylinder engines

5 summary

in view of the failures of CY6102 diesel engine shock absorber, such as falling off and oil leakage for many times, the Schroeder locknut was introduced, and the corresponding structural changes were made to the shock absorber, and the following results were achieved:

(1) the shock absorber was eradicated

(2) the shock absorption performance of the shock absorber was improved

(3) the improved shock absorber has simple structure, few parts and convenient assembly

(4) due to the cancellation of the cone sleeve, the manufacturing cost of the improved shock absorber is greatly reduced, and the maintenance cost is also reduced

(5) the reliability of the whole machine is improved due to the simple and reliable structure and the improved vibration damping performance of the shock absorber


1 mechanical design manual International Science and technology feast "dinner" nbsp; New material industry: Ningbo, Beijing: Chemical Industry Press, 2002.1

2. Technical report of the spilon locknut Shanghai: China wholly-owned company of American firm, June, 2002 (end)

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