• Title/Summary/Keyword: Gear Clearance

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Analytical Study on Improvement in Load Sharing for Planetary Gear Set using Floating Ring Gear

  • Chung, Woo-Jin;Choi, Kyujeong;Oh, Jooseon;Park, Young-Jun;Lee, Ki-Hun
    • Journal of Biosystems Engineering
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    • v.43 no.4
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    • pp.263-272
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    • 2018
  • Purpose: The load on the planet gear of a planetary gear set is uniformly distributed. However, manufacturing and assembly errors cause uneven load sharing in the planetary gear set. To solve this problem, most studies have suggested applying a floating sun gear to the planetary gear set. However, the effect of the floating ring gear and floating carrier has not been extensively studied. This study aimed to investigate the effect of the floating ring gear. Methods: Two models were developed; one was the fixed ring gear model, and the other was the floating ring gear model. In the fixed ring gear model, the clearance between the ring gear and the housing was $0{\mu}m$, and in the floating ring gear model, the clearance was from $10{\mu}m$ to $100{\mu}m$. The load sharing of the planetary gear set was evaluated by the load sharing factor. Results: Our study showed that with increase in clearance, the load sharing factor of the planetary gear set approached unity. In addition, when the clearance increased above a certain level by which a fully floating ring gear was achieved, the load sharing factor was not affected by the clearance. Conclusions: This indicates that the fully floating ring gear increased the power density of the planetary gearbox by uniformly dividing the load of the planetary gear set. For this reason, the size of the gearbox could be decreased by using a fully floating ring gear.

Study on Noise Reduction of an Industrial Take-out Robot (산업용 취출로봇의 소음 저감에 대한 연구)

  • Cho, Jae-Yun;Kim, Deok-Su;Chung, Jin-Tai
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.1
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    • pp.41-46
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    • 2011
  • In this paper, we experimentally investigate factors that decrease in noise of a industrial take-out robot at driving state. For this, we analyse change in the noise of the take-out robot with gear machining accuracy and clearance. In order to calculate the noise related to gear machining accuracy that is based upon the Japanese Industrial Standard(JIS), we equally increase motor speed from 0 rpm to 1250 rpm. In addition, to investigate influence of clearance on noise, we evenly change clearance from 0.5 mm to 1.2 mm. These experiments show that clearance is more effective factor than gear machining accuracy to reduce the noise of the take-out robot.

Two-dimensional numerical simulation of volumetric gear pump flow (회전용적형 기어펌프 유동의 2차원 수치해석)

  • Lee, Jung-Ho;Park, Jong-Won;Kim, Tae-Goo;Lee, Sang-Wook
    • The KSFM Journal of Fluid Machinery
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    • v.13 no.5
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    • pp.17-21
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    • 2010
  • A volumetric gear pump is often used in extensive industrial applications to provide both high pressure and sufficiently high flow rate by physical displacement of finite volume of fluid with each revolution. To better understand the unsteady flow characteristics within the pump, numerical simulations were conducted by using moving dynamic meshing (MDM) techniques in commercially available CFD software, FLUENT. The effects of rotor clearance size and rotational speed of rotor on the flow characteristics, specially the temporal variation of velocity and pressure field, which is a main source of flow noise, was investigated. The results showed that significant reverse flow is developed in the rotor clearance and that its size is one of the most important factors affecting flow characteristics and pressure pulsation.

Mode Characteristics of Spur Gears and Ball-Bearing Stiffness (볼 베어링의 강성과 스퍼기어 계의 모드 특성)

  • Park, Chan IL
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.5
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    • pp.489-495
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    • 2016
  • This study focuses on a detailed ball-bearing model for spur gears. The nonlinear ball-bearing stiffness with radial clearance is derived and calculated. The bearing stiffness is used to the 3-degree-of-freedom (DOF) spur gear system model. The mode characteristics of the gear system model are analyzed and verified by performing finite-element analysis (FEA). From the results, the bearing stiffness on the radial clearance was more sensitive under low-load conditions compared to high-load conditions. The bearing stiffness significantly affected the gear dynamics in the low-frequency region, while the mesh stiffness affected the high natural frequency.

A Study on the Design of Fuel Transfer Pumps Gear Part for the Aircraft (항공기용 연료이송펌프 기어부 설계에 관한 연구)

  • Lee, Jung-hoon;Kim, Joon-tae
    • Journal of Aerospace System Engineering
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    • v.14 no.1
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    • pp.1-7
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    • 2020
  • This paper discusses a series of procedures and results for designing the gear part of a fuel transfer pump for an aircraft, developed as an independent technology for the first time in Korea. A gear pump type is selected because the design requirements of the fuel transfer pump are met by a gear pump with a characteristics of less leakage inside than a vane pump with superior overall performance. The gear housing is designed with suitable clearance, considering the outer diameter of the gear, which is the main factor on which the flow can be determined. Additionally, the calculation of the required hydraulic and axial force for the motor to drive the fuel transfer pump was performed.

FLUID-STRUCTURE INTERACTION ANALYSIS OF EXTERNAL GEAR PUMP (회전용적형 기어펌프의 유체-구조연동 전산해석)

  • Lee, J.H.;Kim, T.G.;Lee, S.W.
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.83-85
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    • 2010
  • A hydraulic gear pump is widely used in many industrial applications to provide both high pressure and high flow rate by physical displacement of finite volume of fluid with each revolution. In this study, two dimensional fluid-structure interaction simulation of gear pump flow was carried out to examine detailed complex flow patterns and structural stress distribution on rotors by using a commercial software ADINA. The effect of rotor clearance size on the flow characteristics, specially the temporal variation of velocity and pressure field, which is a main source of flow noise, also was investigated.

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Influence of Working Variables in Simplified Gear Shaving Process (단순 기어형상의 셰이빙가공에 있어서 작업 변수의 영향)

  • Lee, K.S.;Jung, J.Y.;Kim, J.H.
    • Transactions of Materials Processing
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    • v.19 no.5
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    • pp.290-295
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    • 2010
  • Shaving technology is one of the significant metal forming technologies which can make the smooth and fine sheared surface of products after shearing process. The sheared surface on the side wall of the cutting edge is very important because it functions as a basic surface for measuring the dimensions of product. Effective sheared surface after shaving can be influenced by several working variables such as shaving allowance, shaving clearance, type of material and profile of cutting edge. The influence of these variables on shaving characteristics was investigated in this study. A cut-off die to make the simplified gear-shaped products was manufactured. Three kinds of sheet metals (AL5052, SPCC and SAPH440) of 3mm thickness were firstly sheared and then shaved for four shaving allowances and three sharing clearances. It was shown through experiments that the optimum working condition to give the maximum effective sheared surface in shaving was found ; Shaving allowance is 0.2mm and Shaving clearance is 0.01mm.

Optimization of Mold for Fineblanking Forming of Sector Gear for Recliner (리클라이너 용 섹터기어의 파인 블랭킹 성형을 위한 금형의 최적화)

  • Lee, K.Y.;Nam, K.W.;Moon, C.K.
    • Journal of Power System Engineering
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    • v.15 no.6
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    • pp.53-58
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    • 2011
  • To optimization of mlod for fineblanking forming of sector gear of recliner, it was analyzed the effect of clearance, V-ring height, V-ring position, blank holding force and counter punch force. In case of 0.003 mm of clearancs, the finest shear plane was obtained, but optimization between die and punch clearance was 0.005 mm. The height of V-ring was 0.7 mm. In case of increasing of hold force, the size of shear plane got better and the decrement of thickness became smaller. Both the size of shear plane and the decrement of thickness increased according to increasing of counter punch force.

Study on the Direct Steering System using Rack and Pinion for Ultra-Small Vehicles (랙 & 피니언 기어를 이용한 소형 자동차의 직접 조향 방식에 관한 연구)

  • Kim, Soon-Ho;Kang, Min-Cheol
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.1
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    • pp.127-134
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    • 2002
  • This study present a direct steering system using rack and pinion for ultra-small vehicles. The traditional small vehicles for special use had the limitation of space by reason of short wheel tread. These vehicles has adopted a indirect steering system or a center arm system for steering. The disadvantages of these system were deterioration of gear efficiency and increase of parts. For direct-linkage to both knuckles, steering system is made up of out-side tie rods, tie-rod ends, and gear box. Thus, the proposed system has a minimum number of parts. The experimental results show a maximum efficiency at minimum steering angle and a minimum clearance circle. These effects were accomplished by adopting a Ackerman-Jantaud theory.

Flow Analysis for Optimal Design of Small Gear Pump (소형 기어펌프 최적화 설계를 위한 유동해석)

  • Lee, Suk-Young;Kim, Seung-Chul
    • Journal of Energy Engineering
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    • v.24 no.1
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    • pp.88-96
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    • 2015
  • Gear pump has a simple structure high reliability, easy operation and maintenance, widely used as a source of hydraulic system of hydraulic. In general, the gear pump was designed using variety of variables, the variables through the analysis of the mass flow rate and efficiency. In this paper, three-dimensional flow of the gear pump, in order to produce the optimal design of product, analysis was performed by using commercial software ANSYS v15.0 CFX. And then, combination of design parameters selected by ANSYS was carried out to confirm the simulation result. The efficiency and mass flow rate of the gear pump were studied by varying its rotational speed and the clearance between the gear tip and the housing. In the simulation results, as the rotational speed were increased, the average mass flow rate and efficiency increased. Furthermore, as the clearance between the gear tip and the housing was increased, the average mass flow rate and efficiency decreased.