Planetary gear train is a critical transmission component in large equipment such as helicopters and wind turbines. Conducting damage perception of planetary gear trains is of great significance for the safe operation...Planetary gear train is a critical transmission component in large equipment such as helicopters and wind turbines. Conducting damage perception of planetary gear trains is of great significance for the safe operation of equipment. Existing methods for damage perception of planetary gear trains mainly rely on linear vibration analysis. However, these methods based on linear vibration signal analysis face challenges such as rich vibration sources, complex signal coupling and modulation mechanisms, significant influence of transmission paths, and difficulties in separating damage information. This paper proposes a method for separating instantaneous angular speed (IAS) signals for planetary gear fault diagnosis. Firstly, this method obtains encoder pulse signals through a built-in encoder. Based on this, it calculates the IAS signals using the Hilbert transform, and obtains the time-domain synchronous average signal of the IAS of the planetary gear through time-domain synchronous averaging technology, thus realizing the fault diagnosis of the planetary gear train. Experimental results validate the effectiveness of the calculated IAS signals, demonstrating that the time-domain synchronous averaging technology can highlight impact characteristics, effectively separate and extract fault impacts, greatly reduce the testing cost of experiments, and provide an effective tool for the fault diagnosis of planetary gear trains.展开更多
To select or develop an appropriate actuator is one of the key and difficult issues in the study of semi-active controlled landing gear. Performance of the actuator may directly affect the effectiveness of semi-active...To select or develop an appropriate actuator is one of the key and difficult issues in the study of semi-active controlled landing gear. Performance of the actuator may directly affect the effectiveness of semi-active control. In this article, parallel high-speed solenoid valves are chosen to be the actuators for the semi-active controlled landing gear and being studied. A nonlinear high-speed solenoid valve model is developed with the consideration of magnetic saturation characteristics and verified by test. According to the design rule of keeping the peak load as small as possible while absorbing the specified shock energy, a fuzzy PD control rule is designed. By the rule controller parameters can be self-regulated. The simulation results indicate that the semi-active control based on high-speed solenoid valve can effectively improve the control performance and reduce impact load during landing.展开更多
On the basis of deep investigation of locomotive traction gears manufactured at home and abroad , a variety of measures are putted forward to improve the driving load-bearing capacity and working life of our country&#...On the basis of deep investigation of locomotive traction gears manufactured at home and abroad , a variety of measures are putted forward to improve the driving load-bearing capacity and working life of our country's high-speed locomotive traction gears. The measures include the fol- lowing five aspects : optimally selecting the material and heat treatment process , optimally designing the tooth profile . reasonably choosing the manufacture accuracy and technique , optimally choosing the lubricant and the way of lubrication and seal , improving the dynamic feature of the gearing. In the respect of the tooth profile , a hob with optimal cutter angles is designed to make root thickness on the dangerous section as large as possible and the stress concentration as small as possible. Ad- dendum modification coefficient is optimized to minimize the maximum flash temperature in the course of meshing. Finally . finite element analysis method is used to calculate the deformation and the stress of teeth accurately. And on this basis , optimal profile correction and axial modification have been designed with regard to the start , continuious running and high speed travel of the loco- motive .展开更多
A cycloidal speed reducer employing gears with permanent magnets acting as teeth is described. The magnets, which have their axes radially oriented in both the orbiting gear and the fixed internal gear, are inserted i...A cycloidal speed reducer employing gears with permanent magnets acting as teeth is described. The magnets, which have their axes radially oriented in both the orbiting gear and the fixed internal gear, are inserted in holes drilled in nonmagnetic rims without protruding from the cylindrical exposed surfaces. Because the orbiting gear is not restrained radially, it contacts the fixed gear and rolls on its inner surface. A normal force is developed at the contact point between the gears to balance the magnetic attraction and the centrifugal force of the orbiting gear. The friction available due to this normal force increases the transmission’s torque capacity, which is further increased by elimination of the gap between the gears. Also, the radial load on the supporting orbiting gear bearing is eliminated. A prototype with a reduction ratio of 26 is being tested.展开更多
文摘Planetary gear train is a critical transmission component in large equipment such as helicopters and wind turbines. Conducting damage perception of planetary gear trains is of great significance for the safe operation of equipment. Existing methods for damage perception of planetary gear trains mainly rely on linear vibration analysis. However, these methods based on linear vibration signal analysis face challenges such as rich vibration sources, complex signal coupling and modulation mechanisms, significant influence of transmission paths, and difficulties in separating damage information. This paper proposes a method for separating instantaneous angular speed (IAS) signals for planetary gear fault diagnosis. Firstly, this method obtains encoder pulse signals through a built-in encoder. Based on this, it calculates the IAS signals using the Hilbert transform, and obtains the time-domain synchronous average signal of the IAS of the planetary gear through time-domain synchronous averaging technology, thus realizing the fault diagnosis of the planetary gear train. Experimental results validate the effectiveness of the calculated IAS signals, demonstrating that the time-domain synchronous averaging technology can highlight impact characteristics, effectively separate and extract fault impacts, greatly reduce the testing cost of experiments, and provide an effective tool for the fault diagnosis of planetary gear trains.
基金Aeronautical Science Foundation of China (04B52012, 98B52023)
文摘To select or develop an appropriate actuator is one of the key and difficult issues in the study of semi-active controlled landing gear. Performance of the actuator may directly affect the effectiveness of semi-active control. In this article, parallel high-speed solenoid valves are chosen to be the actuators for the semi-active controlled landing gear and being studied. A nonlinear high-speed solenoid valve model is developed with the consideration of magnetic saturation characteristics and verified by test. According to the design rule of keeping the peak load as small as possible while absorbing the specified shock energy, a fuzzy PD control rule is designed. By the rule controller parameters can be self-regulated. The simulation results indicate that the semi-active control based on high-speed solenoid valve can effectively improve the control performance and reduce impact load during landing.
文摘On the basis of deep investigation of locomotive traction gears manufactured at home and abroad , a variety of measures are putted forward to improve the driving load-bearing capacity and working life of our country's high-speed locomotive traction gears. The measures include the fol- lowing five aspects : optimally selecting the material and heat treatment process , optimally designing the tooth profile . reasonably choosing the manufacture accuracy and technique , optimally choosing the lubricant and the way of lubrication and seal , improving the dynamic feature of the gearing. In the respect of the tooth profile , a hob with optimal cutter angles is designed to make root thickness on the dangerous section as large as possible and the stress concentration as small as possible. Ad- dendum modification coefficient is optimized to minimize the maximum flash temperature in the course of meshing. Finally . finite element analysis method is used to calculate the deformation and the stress of teeth accurately. And on this basis , optimal profile correction and axial modification have been designed with regard to the start , continuious running and high speed travel of the loco- motive .
文摘A cycloidal speed reducer employing gears with permanent magnets acting as teeth is described. The magnets, which have their axes radially oriented in both the orbiting gear and the fixed internal gear, are inserted in holes drilled in nonmagnetic rims without protruding from the cylindrical exposed surfaces. Because the orbiting gear is not restrained radially, it contacts the fixed gear and rolls on its inner surface. A normal force is developed at the contact point between the gears to balance the magnetic attraction and the centrifugal force of the orbiting gear. The friction available due to this normal force increases the transmission’s torque capacity, which is further increased by elimination of the gap between the gears. Also, the radial load on the supporting orbiting gear bearing is eliminated. A prototype with a reduction ratio of 26 is being tested.
