• Title, Summary, Keyword: Inner Rotor

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Design of Gerotor with Pin-tooth Inner Rotor (핀치형 내부로터의 제로터 설계)

  • Lee, Sung-chul
    • Tribology and Lubricants
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    • v.36 no.2
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    • pp.64-67
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    • 2020
  • In the conventional gerotor design, the circular arc tooth of the outer rotor is first introduced, and then the inner rotor profile is generated by simulating the outer rotor motion while the inner rotor is fixed. The profile generation of tooth meshing exhibits relativity; therefore, the outer rotor profile can be generated by the movement of the inner rotor. In this study, we propose the design of a gerotor with a pin-tooth inner rotor. First, the pin-tooth inner rotor is devised, and then the outer rotor profile is generated. The profile of the inner rotor is simply composed of equally arranged pins along a circle. The root of the inner rotor is designed as a conjugated arc of two pins. The trajectory of the pin center is obtained by the inner rotor operation, and then the outer rotor profile is determined as a parallel curve of the trajectory. In this gerotor design, the inner rotor has a simple configuration, and contact occurs between the pin parts of the inner rotor and the whole profile of the outer rotor. This affects the material selection and machining process. The pin tooth can be used to design the outer and inner rotors, enabling a double gerotor mechanism corresponding to a planetary gear system.

Design and Feasibility Study of Double Gerotor (이중 제로터의 설계 및 응용 가능성에 대한 연구)

  • Lee, Sung-chul
    • Tribology and Lubricants
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    • v.35 no.4
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    • pp.215-221
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    • 2019
  • A gerotor set consists of two elements, an inner rotor and an outer rotor. The outer rotor has one more tooth than the inner rotor and has its centerline positioned at a fixed eccentricity from the centerline of the inner rotor. Although gerotors come in a variety of geometric configurations, all gerotor sets share the basic principle of having generated tooth profiles that provide continuous tight sealing during operation. The size of the gerotor is proportional to the number of teeth and the amount of eccentricity. The interior of an inner rotor with a large number of teeth has an enough space to include other machine elements. In this paper, the double gerotor mechanism, constructed by putting a small gerotor in the interior of a large inner rotor, is conceptualized. The double gerotor set is composed of an inner rotor, a planetary rotor, and an outer rotor. The inside profile of the planetary rotor corresponds to the outer rotor profile of the small gerotor, and the outside profile is the inner rotor profile of the large gerotor. In the double gerotor, the centers of the inner and the outer rotor are coincident because the eccentricities of two gerotors are balanced. The operation of a double gerotor is examined by analyzing the planetary motion, and a feasibility study for application of the double gerotor for hydraulic motors and pumps is performed. The double gerotor set has much application potential as a component of hydraulic systems.

Profile Design of the Inner Rotor of a Gerotor by the Composite Curve of Circular Arcs (원호조합곡선에 의한 제로터 내부로터의 형상설계)

  • Lee Sung-Chul
    • Tribology and Lubricants
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    • v.22 no.2
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    • pp.79-86
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    • 2006
  • As the gerotor set with ideal profile meshes too tight, the reduction in the size of the rotor is generally adopted for a smooth operation. In this paper, a method of the profile modification for providing clearances was proposed. The meshing properties of the gerotor were analyzed and the non-boundary section of the inner rotor was identified, which denoted that the adjacent chambers were in the same pressure state. Clearances were imposed on the non-boundary section of the inner rotor, and then the profile of that section was modified as a composite curve of arcs. The other sections of the inner rotor were also interpolated as arcs. Thus, the whole profile of the inner rotor was designed as a composite curve of arcs.

A Study on the Design Procedure of the Eight Pole Magnetic Bearings for the Inner-rotor and the Outer-rotor Type

  • Lee, Jun-Ho;Park, Chan-Bae;Lee, Byung-Song;Lee, Su-Gil;Kim, Jae-Hee;Jung, Shin-Myung;Lee, Hyung-Woo
    • Journal of Electrical Engineering and Technology
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    • v.8 no.6
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    • pp.1424-1430
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    • 2013
  • This paper presents design procedure of the magnetic bearings used for high-speed electric machines and flywheel energy storage systems. Magnetic bearing can be categorized by inner-rotor type and outer-rotor type according to the position of the rotary disc. These two types are applicable based on application environments such as application space, required attraction force, and controllability. Magnetic bearing is generally designed based on the ratio (geometrical coefficient or geometrical efficiency) of pole width to rotor journal radius but proper ratio is only decided by the analysis. This is the difficulty of the magnetic bearing design. In this paper, proper design technology of the inner-rotor type and outer-rotor-type eight pole magnetic bearings is introduced and compared with the FEM analysis results, which verifies the proposed design procedure is suitable to be applied to the design of the magnetic bearings for the industrial applications and flywheel energy storage system.

Experimental of the Rotaing Cryogenic System (회전하는 극저온 시스템의 단열 특성에 관한 실험적 연구)

  • 이창규;정상권
    • Progress in Superconductivity and Cryogenics
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    • v.2 no.1
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    • pp.7-13
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    • 2000
  • A rotating cryogenic system was designed similar to the cooling system for the rotor of a superconducting generator. The experimental rotor has an inner vessel which simulates the winding space of an actual superconducting rotor, and a torque tube of comparable design. This paper describes the evaluation of the total heat leak into the inner vessel that leads to the study of the heat transfer characteristic of the rotating cryogenic system. To examine the insulation performance of the experimental rotor. temperature was measured at each part of the system at various rotaing speeds from 0 rpm to 600 rpm. Total heat leak into the inner vessel was calculated by measuring the boil-off rate of liquid helium. Conduction heat leak to the inner vessel was obtained by the vent tube, and radiation heat leak was calculated by subtracting the conduction heat lent from the total heat leak. There seemed to be no rotaional dependency of total heat leak at least up 600 rpm.

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Finite Element Analysis of a Inner-Rotor Type BLDC Motor without Rotor Core (회전자 철심이 없는 내전형 BLDC 모터의 유한요소 해석)

  • Chang, Hong-Soon;Jung, In-Soung;Baek, Soo-Hyeon
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.49 no.10
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    • pp.652-658
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    • 2000
  • In many cases, ferrite magnets of ferrite bonded magnets used in inner-rotor type small brushless DC(BLDC) motors do not have rotor core. The magnetization directions of permanent magnets do not have only parallel or radial direction. In this case, the characteristics of magnets are different from cored type ones which have uniform magnetization direction. In this paper, the magnetization directions and intensities of a ferrite magnet and a ferrite bonded magnet are analyzed by finite element analysis for magnetization procedure. The characteristics of inner-rotor type BLDC motor are analyzed by using the analyzed results. The validity of the method is verified by comparing the analyzed results with measured ones.

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On the Design Parameters of Gerotor Hydraulic Motors (제로터 유압 모터의 설계 변수에 관한 연구)

  • 김충현;김두인;안효석;정태형;이성철
    • Tribology and Lubricants
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    • v.15 no.1
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    • pp.17-23
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    • 1999
  • A Gerotor hydraulic motor is a planar mechanism consisting of a pair of rotors one of which encloses another rotor. The motion of the inner-rotor relative to the outer-rotor is produced by the pressure difference between the adjacent chambers. A design method of inner-rotor tooth profile using unit tangential vectors is presented in this work. Based on the relationships derived, the influence of the eccentricity of inner-rotor and the radius of circular arc tooth on the flow rate, torque and curvatures were investigated. It was shown that the flow rate and mean torque is proportional to eccentricity, but inversely proportional to the radius of circular arc teeth. Also, the maximum value of the equivalent curvature is increased as the eccentricity and the radius of circular arc teeth increased.

Rotordynamic Characteristics of an APU Gas Turbine Rotor-Bearing System Having a Tie Shaft

  • Lee, An-Sung;Lee, Young-Seob
    • Journal of Mechanical Science and Technology
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    • v.15 no.2
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    • pp.152-159
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    • 2001
  • In this paper it is intended to set-up a sound model of the 60,000rpm 100kW prototype APU gas turbine rotor-bearing system, and particularly to investigate the influences of the tie shaft on the rotordynamic characteristics of the entire APU gas turbine rotor-bearing system, employing the dual shaft model. Firstly, a mock-up APU rotor has been constructed to test and verify the model. Analytical natural frequency results have agreed with the corresponding modal test ones to within 5% difference. Then, the rotordynamic characteristics of the prototype APU rotorbearing system have been investigated. Natural vibration and unbalance response analyses results have shown that the inner tie shaft resonance can cause high enough vibration of the outer main rotor shaft. This could be a concern as the rotor journals operate on very thin air film at high speed. It is concluded as a conservative design practice that the inner tie shaft should be explicitly modeled in the rotordynamic analysis of the APU rotor-bearing system.

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Design and Analysis of Gerotor with Generalized Shapes for Power-Steering Units (파워 스티어링 유닛용 일반형상 제로터의 설계 및 해석)

  • Jeong, Jae-Tack;Shin, Soo-Sik;Kim, Kap-Tae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.7
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    • pp.891-896
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    • 2010
  • A gerotor is used in power-steering units (PSUs) as well as in hydraulic motors or pumps. The inner rotor is developed on the basis of the shape of the outer rotor tooth, which normally has one arc. The method of generating inner rotor on the basis of a generalized shape of outer rotor is analyzed with a view to improve PSU characteristics. An arc-shaped outer rotor with two curvatures was used in the analysis; design parameters such as the shape and curvature of the inner rotor, the flow rate of the gerotor, the position of contact point, and slip velocity are calculated, and these results are shown. This analysis enables us to develop a new design of compact PSUs.