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Ring gear is an important part of high power transmission system. Because of its thin wall and low stiffness, it is easy to cause deformation in the process of gear shaping, which affects its accuracy. Therefore, how to ensure the quality of gear ring gear insertion is an urgent research topic. In this paper, the influence of cutting parameters of gear shaper on the deformation of gear ring is studied by finite element simulation and practical test. The results show that the influence of main cutting parameters on the deformation of 42CrMo ring gear is radial feed, circumferential feed, stroke speed, and cutting depth. In the actual gear shaping process, the cutting parameters can be adjusted according to this deformation law, so as to control the deformation of the ring gear. [ABSTRACT FROM AUTHOR]

Complex mechanical products involve many specialized fields such as machinery, electronics, hydraulics, and computers, so their initial cost is usually higher. In addition, regular and irregular maintenance are also needed to extend their service life, so that the cost of the product in its life cycle will be increased. Therefore, for the manufacturing enterprises of complex mechanical products, it is very important to achieve the best matching between reliability and economy. In order to survive in the fierce market competition, it is necessary to compare with other similar products in the market, so as to clearly understand the level of their products, find out the gap, and improve it. However, the existing product reliability assessment methods based on probability and statistics theory cannot provide such help for them to solve this problem. Therefore, this paper puts forward a method to evaluate and improve complex mechanical products by using a data envelopment analysis (DEA) model considering the reliability and economy of product comprehensively. Through the relative effectiveness of DEA, the same type of products on the market can be compared, providing specific method for enterprises to evaluate and improve their own product level to achieve the best matching of economy and reliability. This paper introduces the principle and steps of this method and takes the hydraulic component manufacturing enterprise as an example to carry out practical research, which verifies the feasibility and effectiveness of this method. [ABSTRACT FROM AUTHOR]

Hydraulic reciprocating seals are dynamic sealing elements used in hydraulic actuators that play a very important role in preventing leakage. In this paper, a multisensor monitoring scheme including Fiber Bragg Grating sensors, fluid pressure sensors, and reciprocating displacement sensor was designed to analyze the leakage of hydraulic cylinder in a complete reciprocating work cycle. A complete hydraulic cylinder reciprocating cycle includes the extending process of piston rod, the full extension of piston rod, the retracting process of piston rod, and the full retraction of piston rod. Through an especially designed test bench, multisensor monitoring data were obtained under different wear degree of the piston seals. The analysis results show that there will be a “pull-back effect” in the return stroke of the piston seal. Therefore, leakage-based monitoring methods used in existing studies may not accurately reflect the wear of piston seals. If it is desired to detect wear of the piston seal during its actual operation, the contact pressure of the piston seal must be monitored. The paper also discusses the wear feature extraction method and how to deal with multiple features extracted from multisensor monitoring signals. [ABSTRACT FROM AUTHOR]

Tungsten carbide end mills have been widely used for titanium alloys machining, but they have severe problems of high damage rate, which lead to abnormal increase of the machining cost. Although there are many relevant research such as the material preparation and the structural design of cutting tools, the parameter optimization of titanium alloys machining process and so on, but this problems still have not been solved very well. Therefore, other possible influencing factors must also be considered. The present study focuses on the preparation of tungsten carbide end mills, an experimental study was conducted which includes the microstructure comparative analysis of the material surface layer in the different positions of tungsten carbide end mills, and the grinding effect comparison of tungsten carbide materials between different grinding parameters. The main findings include: (1) The internal micro cracks already exist in surface layer of cutting edge even these tungsten carbide end mills have not been involved in machining process; (2) In the surface layer of tungsten carbide tools, different types and levels of residual stress will be generated by different grinding process parameters, once they are engaged in the intermittent cutting process, the internal micro cracks and residual stress in the surface layer will have complex interaction with the cutting force and temperature, which can prompt the propagation of the cracks and eventually lead to catastrophic destruction of the cutting edges. It can provide an important basis for the preventive measures to eliminate the potential factors that affect the service life of the cutting tool in the fabrication stages. [ABSTRACT FROM AUTHOR]

• The degradation process of hydraulic reciprocating seal is studied. • The deteriorating parameters are extracted based on monitoring data. • Reliability prediction model of the hydraulic reciprocating seal is established. • The applicable conditions of the reliability prediction model are discussed. It is of great significance to analyze the degradation process of the hydraulic reciprocating seal and accurately predict its reliability for taking corresponding measures timely and avoiding losses and accidents. However, the degradation process of a hydraulic reciprocating seal largely depends on actual working parameters of hydraulic cylinder. Therefore, the performance degradation process of the hydraulic reciprocating seal must be studied according to the actual working process parameters of the hydraulic cylinder. In this paper, the degradation process of hydraulic reciprocating seal is studied in a specially designed experimental system. The experimental data are monitored by fiber Bragg grating (FBG) sensor, pressure sensor and friction sensor. The extraction method of performance degradation parameters of the hydraulic reciprocating seal is studied. The reliability prediction model is established, namely R-N curve, which can describe the performance deteriorating process of the hydraulic reciprocating seal. [ABSTRACT FROM AUTHOR]

In this paper, a pressure compensated sealing method is proposed to solve the problem that the piston rod seal does not have the sealing compensation capability after wear. The pressure compensation simulation and experimental research on piston rod seals with different degrees of wear were carried out. In the experimental study, the monitoring data was collected by fiber Bragg grating sensors, tension sensors, pressure sensors and displacement sensors, and the parameters that reflect the sealing performance and friction characteristics are extracted therefrom. The relationship between the compensation pressure and the parameters under different degrees of wear was analyzed. The results show that the pressure compensation sealing method can improve the sealing performance of the sealing ring. • A pressure compensation method is proposed to improve the sealing ability after the seal is worn. • The method was verified by piston rod seals with different degrees of wear. • Nine parameters were extracted from the data collected by the four sensors. • The pressure compensation seal has certain sealing compensation ability. • The relationship of the sealing performance and friction characteristics is revealed. [ABSTRACT FROM AUTHOR]