# Optimum design of the crosshead of the hottest uni

2022-10-15
• Detail

The main function of universal joint which can bring great value is to transmit torque between shafts on different axes. It is widely used between transmission shafts and coupling forks of all kinds of trucks. It is a weak link to reasonably design the structure of the universal joint spider only to produce the best results. Due to the lack of effective means for comprehensive analysis, the strength of various parts of the product is uneven, some parts of the stress concentration, some parts of the blank is too wide and thick, there is a lot of material waste, which is not conducive to improving the bearing capacity of the product. Therefore, we use three-dimensional modeling and finite element analysis technology to optimize the design of JN150 universal joint spider to achieve the purpose of reducing weight and cost

carry out stress analysis on the cross shaft before optimization

1 Build a three-dimensional model

use pro/e large-scale three-dimensional modeling software to make the three-dimensional model of the cross shaft before optimization. Because many small chamfers and fillets have a great impact on the strength of the cross shaft, they cannot be simplified when building the model. The calculated weight of the model is 2.15kg

2. Stress analysis

use ANSYS large-scale finite element analysis software to analyze the stress of the model. Specific analysis conditions: apply bending load, and the rated static load is 5246.4n m. The allowable stress of the material is 450MPa

Figure 1 shows the stress distribution diagram. From the figure, it can be seen that the maximum stress occurs at journal R, and the maximum stress value is 434mpa, close to the allowable stress 450MPa. If the safety factor of 2.5 times is calculated, the maximum static load that the shaft can bear is 450/434 × five thousand two hundred and forty-six point four × 2.5＝13600N. m。

Figure 1 stress distribution of the cross shaft before optimization

from the stress distribution shown in Figure 1, it can be seen that the stress distribution of the whole cross shaft is uneven, and a large blue area appears in the middle blank part. The stress in this area is very small relative to the maximum stress value, and there is excess material, which can reduce the blank size and achieve the purpose of weight reduction

formulate optimization scheme

according to the stress analysis of the spider, formulate an improvement scheme: the arc at the root of the spider journal is increased from R2 to R4; The journal diameter is increased from 24mm to 26.7mm; The thickness of intermediate blank is reduced from 36mm to 28mm; The diameter of the outer circle of the blank is reduced from 104mm to 96mm

stress analysis of the optimized spider

1 Establish a three-dimensional model

use pro/e large-scale three-dimensional modeling software to make the optimized three-dimensional model of the spider. The model is shown in Figure 2, and the calculated weight is 1.79kg

Figure 2 optimized spider model

2 Stress analysis

use the same conditions to conduct finite element analysis on the optimized spider, and the analysis results are shown in Figure 3. It can be seen from the figure that the maximum stress is still at the journal R, but the maximum stress value is reduced to 297.1mpa, which is far less than the allowable stress value of 450MPa. Compared with the maximum stress value of the cross shaft model before optimization, it is reduced by 136.9 MPa. Plus 2.5 times the safety factor, the maximum static load that the cross shaft can bear after optimization is 450/297.1 × five thousand two hundred and forty-six point four × 2.5＝19866N. m。

Fig. 3 stress distribution diagram of cross shaft after optimization

according to the above analysis results, the bearing capacity of the optimized cross shaft model is increased by 6266n compared with the cross shaft model before optimization m. The increase ratio is (19866-13600) ÷ 13600 × 100%＝46％。 The material was reduced by 0.36kg, and the weight reduction ratio was (2.15-1. The China Mining Federation also awarded Jixi the title of "graphite city of China" 79) ÷ 2.15 × 100% its output is about 25% higher than that of the traditional screw extruder = 17%

validation

trial produce 20 samples according to the optimized spider, and the average weight of 20 samples is 1.78kg; Before optimization, the actual average weight of the sample was 2.14 kg, and the actual weight reduction ratio was 20%, which achieved the expected weight reduction effect

the load-bearing capacity of the optimized cross axle is verified by bench performance test. Two pieces of cross axle before and after optimization are taken for static torsion test. The test results are as follows: the static torsion strength of two pieces of cross axle before optimization is 16608 N.m and 15702 N.m respectively, and the static torsion strength of two pieces of cross axle after optimization is 19158n respectively m、19172N. m. It is basically consistent with the results of finite element analysis, and the actual increase of bearing capacity is 18%

conclusion

through the product optimization design and verification of JN150 universal joint spider using three-dimensional modeling and finite element analysis technology, the average weight of each part is reduced by 0.36kg, and the bearing capacity of the spider is increased by 18%. At the same time, the expected goal of weight reduction, consumption reduction and performance improvement is achieved

it is very effective to apply finite element analysis and optimization design to reduce the weight of parts and improve the performance, especially in the environment of increasingly scarce global resources, which is worthy of our promotion and application in a broader field. (end)

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