Lubrication Mode and Selection of the Helicopter Transmission System Roller Bearing

2011 ◽  
Vol 86 ◽  
pp. 156-161
Author(s):  
Jun Peng Qiu ◽  
Mei Yin ◽  
Ling Song Guo
Keyword(s):  
Roller Bearing ◽  
Essential Element ◽  
Transmission System ◽  
Bearing Life ◽  
Lubrication Mode ◽  
Bearing Design ◽  
Helicopter Transmission ◽  
Design And Manufacture ◽  
Normal Work ◽  
Selection Of

The bearings will directly affect the performance of helicopter transmission system whether they are in normal work or not. Lubrication is the essential element for the normal work of bearings. Under the condition of the bearing design and manufacture technique, material technique is becoming more and more advanced, and lubricant becomes “the fifth main part”, which has been got a wide-ranged agreement. One of the most critical factors to improve bearing life is lubricant. This paper analyzes lubrication type and mode, and the failure of helicopter transmission system roller bearing caused by improper lubrication. It further explains the importance of lubrication to the bearings. And how to select lubrication mode and lubricant to improve the bearing life is also summed up.

Five Pad Tilting Pad Bearing Design and Lateral Vibration Characteristics of Small Gas Turbine Supported by It and Roller Bearing

2011 ◽  
Author(s):  
Jin Woong Ha ◽  
Ji Ho Myung ◽  
Jhin Ik Suk
Keyword(s):  
Rigid Body ◽  
Gas Turbine ◽  
Dynamic Properties ◽  
Roller Bearing ◽  
Rigid Body Mode ◽  
Conical Shape ◽  
Tilting Pad ◽  
Bearing Design ◽  
Industrial Gas Turbine ◽  
Selection Of

In tilting pad bearing design process, the selection of the proper configuration type of either a Load-Between-Pad (LBP) or Load-On-Pad (LOP) as well as preload and pivot offset conditions is to be carefully considered. Also the bearing needs to be designed in order to be suited for the rotor-bearing system and operating condition. In this paper, it is observed that the static and dynamic characteristics of a five pad tilting pad bearing for the LBP and LOP configurations are influenced by the variation of preload and pivot offset. In this context, rotor dynamic analysis of the 5 MW industrial gas turbine supported by the tilting pad bearing at the front and roller bearing at the rear is carried out based on the dynamic coefficients of the tilting pad bearing investigated. The result shows that two rigid body critical modes experience various changes according to the influence of the tilting pad bearing uniquely applied to one side of this machine. Mainly, the second critical speed, the rigid body mode of conical shape with high whirling in the tilting pad bearing, is significantly changed by preload and pivot offset regardless of the LBP and LOP configurations. And the first critical mode, the rigid body mode of conical shape with high whirling in the roller bearing, is sensitively affected by preload applied to the LOP configuration and by its asymmetric dynamic properties.

Failures in the Development and Service of the Helicopter Transmission System

2011 ◽  
Vol 86 ◽  
pp. 74-81 ◽  
Author(s):  
Tong Bo Xue ◽  
Gai Qi Li
Keyword(s):  
Transmission System ◽  
Corrective Action ◽  
Mode Characteristic ◽  
Helicopter Transmission ◽  
Design And Manufacture

In this paper the failures which may occur in the development and service of the helicopter transmission system are discussed. The mode, characteristic, cause and corrective action for the failures are summarized. Besides, the measures of the design and manufacture to eliminate the failures are recommended.

Effect Analysis of Polarization Aberration in the Non-Line-of-Sight Azimuth Transmission

2021 ◽  
Author(s):  
Zhiyong Yang ◽  
Junchen Song ◽  
Wei Cai ◽  
Danqiu Qiao ◽  
Gaoxiang Lu
Keyword(s):  
Normal Incidence ◽  
Transmission Error ◽  
Transmission System ◽  
Line Of Sight ◽  
Polarization Angle ◽  
Effect Analysis ◽  
Polarized Beam ◽  
Polarization Maintaining ◽  
Selection Of ◽  
Non Line Of Sight

Abstract Focusing on the problem that the polarization aberration caused by the non-normal incidence of the polarized beam affects the accuracy of the azimuth transmission during the fiber coupling process of the non-line-of-sight azimuth transmission system, this paper starts from the principle of non-line-of-sightazimuth transmission. The polarization aberration relation of the lens-fiber combined interface is established based on the Fresnel formulafor the attenuation difference between the horizontal and vertical electric vectors. Further, the azimuth solution model affected by polarization aberration is established. Numerical simulation results show that in non-normal incidence, no polarization aberration will occur when the polarization angle between the incident ray and incident surface is 0° or 90°. Otherwise, the polarization aberration changes toward the incident surface, and the azimuth transmission error will increase with the increase of the polarization aberration. Last, the optimization measures are proposed. This is of great significancefor further improvement of the azimuth transmission system based on polarization-maintaining fibers, the selection of the instrument,and the improvement of the system measurement accuracy.

Prediction and test of stable transmission time of spiral bevel gear during a loss-of-lubrication event in helicopter transmission system

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yanzhong Wang ◽  
Kai Yang ◽  
Wen Tang
Keyword(s):  
Transmission System ◽  
Bevel Gear ◽  
Transmission Time ◽  
Tooth Surface ◽  
Spiral Bevel Gear ◽  
Content Type ◽  
Surface Burn ◽  
Spiral Bevel ◽  
Helicopter Transmission ◽  
Stable Transmission

Purpose This paper aims to establish a prediction model of stable transmission time of spiral bevel gear during a loss-of-lubrication event in helicopter transmission system. Design/methodology/approach To observe the temperature change of spiral bevel gear during working condition, a test rig of spiral bevel gear was developed according to the requirements of experiments and carried out verification experiments. Findings The prediction is verified by the test of detecting the temperature of oil pool. The main damage form of helicopter spiral bevel gears under starved lubrication is tooth surface burn. The stable running time under oil-free lubrication is mainly determined by the degree of tooth surface burn control. Originality/value The experimental data of the spiral bevel gear oil-free lubrication process are basically consistent with the simulation prediction results. The results lay a foundation for the working life design of spiral bevel gear in helicopter transmission system under starved lubrication.

scholarly journals A Life Estimation Method of Helicopter Transmission System Key-parts

2018 ◽  
Vol 382 ◽  
pp. 052016
Author(s):  
Qing Mei ◽  
Tiancai Guo ◽  
Tongbo Xue ◽  
Hua Wen ◽  
Zhenrong Huang
Keyword(s):  
Estimation Method ◽  
Transmission System ◽  
Life Estimation ◽  
Helicopter Transmission

scholarly journals Strategies to Control Performance of 3D-Printed, Cable-Driven Soft Polymer Actuators: From Simple Architectures to Gripper Prototype

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 846 ◽  
Author(s):  
Viacheslav Slesarenko ◽  
Seiji Engelkemier ◽  
Pavel Galich ◽  
Dmitry Vladimirsky ◽  
Gregory Klein ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Weight Lifting ◽  
Polymer Actuators ◽  
Cable Channel ◽  
Polymer Actuator ◽  
3D Printed ◽  
Soft Polymer ◽  
Soft Actuators ◽  
Design And Manufacture ◽  
Selection Of

The following is a study of the performance of soft cable-driven polymer actuators produced by multimaterial 3D printing. We demonstrate that the mechanical response of the polymer actuator with an embedded cable can be flexibly tuned through the targeted selection of actuator architecture. Various strategies, such as the addition of discrete or periodic stiff inserts, the sectioning of the actuator, or the shifting of the cable channel are employed to demonstrate ways to achieve more controllable deformed shape during weight lifting or reduce the required actuation force. To illustrate these concepts, we design and manufacture a prototype of the soft polymer gripper, which is capable of manipulating small, delicate objects. The explored strategies can be utilized in other types of soft actuators, employing, for instance, actuation by means of electroactive polymers.

Theoretical Study on the Influence of Planet Gear Rim Thickness and Bearing Clearance on Calculated Bearing Life

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Andreas Fingerle ◽  
Jonas Hochrein ◽  
Michael Otto ◽  
Karsten Stahl
Keyword(s):  
High Efficiency ◽  
Roller Bearing ◽  
The Body ◽  
Fem Model ◽  
Bearing Life ◽  
Bearing Load ◽  
Rolling Elements ◽  
Planet Gear ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

Abstract Planetary gearboxes are becoming more popular due to their high-power density and potentially high efficiency. When the planet bearings are internally mounted, the body of the planet gear has to be hollow. The demand for large outer diameters due to high-load requirements might result in a small planet rim thickness. Depending on the rim thickness, its rigidity may become very low. Due to the low stiffness and the special load conditions caused by the double meshing, the deformation of the planet and its bearings are unique. In this paper, the influence of rim thickness on bearing load and lifetime is examined. The analysis is performed with a finite element method (FEM) model of a planet rim with a built-in cylindrical roller bearing. With the resulting planet deformation from the FEM calculation, the load distribution on the rolling elements in the bearing and the bearing lifetime according to ISO/TS 16281:2008 has been evaluated.

Theoretical Study on the Influence of Planet Gear Rim Thickness and Bearing Clearance on Calculated Bearing Life

2019 ◽  
Author(s):  
Andreas Fingerle ◽  
Jonas Hochrein ◽  
Michael Otto ◽  
Karsten Stahl
Keyword(s):  
High Efficiency ◽  
Roller Bearing ◽  
The Body ◽  
Fem Model ◽  
Bearing Life ◽  
Bearing Load ◽  
Rolling Elements ◽  
Planet Gear ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

Abstract Planetary gearboxes are becoming more popular due to their high power density and potentially high efficiency. When the planet bearings are internally mounted, the body of the planet gear has to be hollow. The demand for large outer diameters due to high load requirements might result in a small planet rim thickness. Depending on the rim thickness, its rigidity may become very low. Due to the low stiffness and the special load conditions caused by the double meshing, the deformation of the planet and its bearings are unique. In this paper, the influence of rim thickness on bearing load and lifetime are examined. The analysis is performed with an FEM model of a planet rim with a built-in cylindrical roller bearing. With the resulting planet deformation from the FEM calculation, the load distribution on the rolling elements in the bearing and the bearing lifetime according to ISO/TS 16281:2008 have been evaluated.

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