Research On Vibration Transmission And Noise Radiation Of Bent-axis Type Hydraulic Piston Motor

The vibration intensity and noise level of hydraulic system are getting higher and higher especially when the hydraulic system develops in the direction of high pressure,high speed,and digitalization,which not only seriously affect service life and reliability of hydraulic components,but also endanger the physical and mental health of workers.Therefore,research on vibration and noise reduction of hydraulic components is attracting more and more attention in the industry.Bent-axis type hydraulic piston motor is widely used in various construction machinery fields because of its high power to weight ratio,high pressure resistance and high speed drive.As an important actuator of hydraulic systems,they are also one of the main noise sources of hydraulic systems.At present,there are few studies on the vibration and noise reduction of axial piston motor.Therefore,this paper takes a certain type of bent-axis type piston motor as the research object,studies the vibration transmission and noise radiation of the motor and guides the structural optimization..The main research contents in this paper are as follows:First of all,the structure and working principle of the bent-axis type hydraulic piston motor are introduced in detail,and the kinematics analysis of the piston and the motion mechanism is carried out.The internal excitation source and its excitation frequency of the bent-axis type piston motor are studied based on the working principle of the plunger motor and the analysis of the motion mechanism.From the excitation source,the internal vibration transmission path of the piston motor is analyzed,and the final receptor of the vibration transmission is the shell of the piston motor.Taking the eccentric and unbalance of the motor rotating body as a single excitation source,the physical model and mathematical model of the internal mechanical vibration transmission path of the bent-axis type piston motor are established.The vibration characteristics of the shell and the rear end cover are obtained by MATLAB programming.Secondly,taking the outer shell of the bent-axis type hydraulic piston motor as the research object,the finite element model of the outer shell is established,and the modal analysis is carried out to obtain its natural frequency and modal shape.Then,the harmonic response analysis is performed for the severely vibrated area,and the vibration characteristics and changing laws of the outer shell of the piston motor at each excitation frequency are studied according to the harmonic response analysis.A boundary element model of the outer shell of the bent-axis type hydraulic hydraulic piston motor is established based on the results of modal analysis and harmonic response analysis.The noise radiation simulation is conducted to obtain a frequency with a large contribution of noise radiation.Then,the topology optimization of the shell structure of the inclined axis type piston motor is performed based on the results of vibration and noise simulation analysis.Combined with the results of modal analysis and topology optimization,the vibration and noise reduction of the shell structure is optimized,the vibration characteristics of the structure are compared before and after the improvement,and then the final structural optimization scheme is determined.The vibration characteristics,strength analysis and noise simulation analysis of the optimized shell structure are carried out to verify the effectiveness of the structure.Finally,based on the existing experimental conditions,vibration and noise test experiments of the piston motor is performed in a semi-anechoic room to study the vibration and noise characteristics of the bent-axis type piston motor.The acceleration frequency spectrum and the acoustic pressure level spectrum of the piston motor under different speeds and different pressures are compared with the theoretical calculation,and the main exciting source and noise source in the motor are identified.The innovation of this paper is that the method of combining the harmonic response with the acoustic boundary element to obtain the vibration and acoustic radiation characteristics of the motor shell,which is helpful to clear the sound radiation of the structure at the design stage and greatly improve the design efficiency.The topology optimization is applied to the study of vibration and noise reduction of the bent-axis type piston motor to guide the structure optimization,which can increase the power density of the plunger motor.And provide a new idea for the vibration and noise reduction of the motor.