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Application of instantaneous speed fluctuation signal in fault diagnosis of axial piston pump |
GU Lichen1, MA Ziwen1*, TIAN Qingqing2, SUN Yu1 |
1. School of Mechanical and Electrical Engineering, Xi′an University of Architecture and Technology, Xi′an, Shaanxi 710000, China; 2. School of Mechanical Engineering, Xi′an Aeronautical University, Xi′an, Shaanxi 710077, China |
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Abstract In view ofthe fact that most of the signals used in valve plate wear fault diagnosis of axial piston pump have non-stationary and nonlinear characteristics. Therefore, a fault diagnosis method of valve plate wear based on instantaneous speed fluctuation(ISF)of axial piston pump was proposed in this paper. In order to overcome the shortcomings of the traditional monitoring signals, the ISF signal has good anti-noise performance and can be transformed into a stable signal in the angle domain after order analysis. The causes of instantaneous speed fluctuation of axial piston pump were revealed through dynamic analysis. The results show that for the axial piston pump with Z pistons, the piston inertia force and the Coulomb friction force at the cylinder/valve plate pair will produce the torque fluctuation Z times the rotational frequency, which will produce a Z-order ISF on the main shaft of the axial piston pump. The change of the pressure in the high pressure cavity of the plunger will produce a torque fluctuation 2Z times of the rotational frequency, which will generate a 2Z-order ISF on the main shaft of the axial piston pump. The theoretical results were verified by experiments under the condition of variable load. The results show that for the axial piston pump with 9 pistons, the variation of the amplitude of the 9th order ISF component can well reflect the different wear condition of the valve plate. With the increase of wear degree of the valve plate deteriorates, the maximum amplitude of the 9th order ISF increases from 1.229 r/min to 2.023 r/min. The amplitude of the 9th order ISF component increases with the aggravation of the valve plate wear.
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Received: 17 April 2020
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