Axial piston pumps are commonly used as key equipment in the petroleum industry to transport crude oil and petroleum products. Outlet flow pulsation refers to the periodic change of pump outlet flow in a certain period of time, which will have a certain impact on the petroleum industry. The export flow pulsation will affect the transportation stability of petroleum products, and the export flow pulsation will also affect the quality of petroleum products. The transition zone of the high and low pressure conversion of the distribution disc throttle groove during the operation of the axial piston pump will affect the flow backflow at its outlet, which further affects the flow pulsation. Therefore, the key parameters of different distribution trays are studied. The influence of the key parameters of the V-groove and the U-groove on the flow pulsation of the distribution plate was studied, and the U-shaped groove was optimized, and a V-shaped opening was added at the end of the U-shaped groove to reduce the flow pulsation.
The hydraulic braking system of metro vehicles has the characteristics of high working pressure,good response characteristics,high efficiency and compact structure.The working principle and structure of hydraulic braking system and hydraulic control unit are analyzed,and the sliding reason of metro vehicle during braking is studied.Based on the characteristics of independent wheels of metro vehicles,the hydraulic braking uses braking deceleration,deceleration change and speed difference as input,and the output is pressure output coefficient.According to experience,fuzzy rules and membership functions are designed.The hydraulic braking anti-skid scheme is designed based on fuzzy control.Through MATLAB simulation analysis,the expected anti-skid effect is obtained,and the effectiveness of fuzzy control in the hydraulic anti-skid scheme is verified.
据中国工程机械工业协会对主要制造企业统计 挖掘机:据中国工程机械工业协会对挖掘机主要制造企业统计,2023年10月销售各类挖掘机14584台,同比下降28.9％,其中国内6796台,同比下降40.1％;出口 7788台,同比下降14.9％. 2023年1-10月,共销售挖掘机163396台,同比下降26％;其中国内74871台,同比下降43％;出口 88525台,同比下降1.04％. 装载机:据中国工程机械工业协会对装载机主要制造企业统计,2023年10月销售各类装载机7517台,同比下降20.4％.其中国内市场销量4339台,同比下降31.2％;出口销量3178台,同比增长1.08％.
Aiming at the characteristics of small volume and high measurement accuracy of valve displacement sensor,an automatic calibration device for valve displacement sensor is designed.In the research process,the structure design and software control of the calibration system are introduced in detail,and the measurement uncertainty is analyzed emphatically.The calibration device can realize the indirect drive of the servo motor,which drives the lead screw.The drive platform connected to the lead screw drives the iron core to move,and the high-precision grating ruler connected to the drive platform feeds back the displacement of the iron core.Automatic calibration can be carried out by analyzing the relationship between the input and output of the sensor.Experiments were carried out on the designed automatic calibration device.The experimental results show that the calibration effect of the device is good,and it is suitable for the calibration of valve displacement sensor(accuracy class 0.01,range less than 200 mm),with high practical value.
This paper introduces the main components of the compressed air system,and takes the pilot plant of a ceramic project as an example,analyzes the specific selection of the air compressor,dryer,filter and air receiver of the compressed air system.For the construction conditions of the compressed air station building,the required conditions are proposed from the civil engineering,HVAC,electrical,water supply and drainage disciplines.
