Research on gas spring funnel type auxiliary device

The new air spring structure adopting the hourglass-type auxiliary spring has the same structure, and the air spring is composed of a combination of a screw seal and a pressure self-sealing. The upper sub-port of the airbag is closely attached to the upper cover by the inner buckle and the screw. It can ensure the sealing reliability of the air spring when the vehicle generates a large lateral displacement through the small radius curve; the lower sub-port of the airbag is pressure-sealed to fit the airbag in the groove of the auxiliary spring. The flexural deformation part of the airbag is fitted by a plurality of arcs and tangent lines of different radii, which not only avoids stress concentration inside the airbag, but also improves the service life of the bellows. The auxiliary spring features a new hourglass structure with low vertical and lateral stiffness. The auxiliary spring is connected in series with the air spring airbag and acts as an emergency spring when the air spring is running without air.

The auxiliary spring is in an operating state and is deformed by a compressive load. When designing the free-form shape, it is necessary to consider the connection of multiple arcs and the amount of deformation under compression load, the distribution of rubber stress, and the position of the center of gravity. Theoretical analysis and calculation Since the new air spring only changes the auxiliary spring of the prototype air spring, this paper only explains the calculation of the auxiliary spring.

The hourglass-type auxiliary spring adopts a new design, and its free-state structure and simplified calculation model are shown. Using MARC finite element analysis software, it is discretized into an 8-equivalent isoparametric HERRMANN incompressible unit. The discrete model has 4176 units and 5040 nodes, including 2970 rubber units and 1206 metal units. Different vertical loads are applied to the calculation model, and the stress distribution under different load conditions is analyzed. The results show that the rubber stress distribution is uniform under various load conditions and there is no stress concentration. The profile of the stress distribution of the section when the vertical loads are 55kN, 90kN and 110kN. In order to assist the load-displacement curve of the spring, the corresponding tangent stiffness can be obtained from this: the stiffness is 2863N/mm when the vertical load is 55kN; the stiffness is 4361N/mm when the vertical load is 90kN; and the stiffness is 110kN when the vertical load is 110kN. 5133N/mm.

Auxiliary spring structure and simplified structure Auxiliary spring section stress distribution cloud map (when vertical load is 55kN) Auxiliary spring section stress distribution cloud map (when vertical load is 90kN) 3 Experimental study to understand the characteristics of hourglass auxiliary spring and its relationship to air The effect of the spring composition is first tested separately on the auxiliary spring, and then the performance of the entire air spring composition is tested and compared with the prototype air spring. The auxiliary spring was subjected to performance tests such as vertical, lateral stiffness test and vertical fatigue. The air spring composition was tested for vertical and lateral stiffness, lateral deformation capacity test and fatigue resistance test.

The air spring fatigue test conducted a torsional fatigue test with an amplitude of 60 mm on an air spring using an hourglass-type auxiliary spring. After the end of the 600,000-cycle fatigue test, the air spring still satisfies the airtightness requirement. Surface inspection of the auxiliary spring after decomposition did not reveal abnormal phenomena such as cracks, delamination, and local bulging, indicating that the hourglass-type auxiliary spring has sufficient fatigue resistance.

The application of the new auxiliary spring structure is based on the advantages of the hourglass-type auxiliary spring, which is gradually being applied to practical products. The Sifang Vehicle Research Institute adopted the improved design of the hourglass-type auxiliary spring, which was approved by Changchun Railway Vehicle Co., Ltd. and New Zealand customers. Later, the line dynamics test was carried out to prove that the indicators were excellent. Since the beginning of mass loading in April 2008, the effect has been excellent. In 2009, in the second phase of the Wuhan Metro Line 1 project, the Sifang Institute once again proposed the design of the hourglass-type auxiliary spring, which has an advantage in comparison with foreign programs. The prototype developed passed the user's first inspection. , got the order.

At the end of the day, the tapered auxiliary spring can achieve lower vertical stiffness, but its lateral stiffness is larger, and the rubber of the tapered auxiliary spring is mainly subjected to shear stress during operation, so the production process is required to be high, and the product is also It is prone to defects; the hourglass-type auxiliary spring is mainly subjected to compressive stress during operation, and the requirements for the production process are relatively simple. Although the hourglass-type auxiliary spring has not been widely promoted, it has more advantages than the existing flat-plate auxiliary spring. With the accumulation of experience in the application of hourglass-type auxiliary springs, related technologies will continue to improve.