• Title, Summary, Keyword: Gear steps

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Study on Accelerated Life Test Design for a Gear Type Lubrication Pump for Automatic Transmission (자동변속기 윤활용 기어펌프의 가속 수명시험 설계에 관한 연구)

  • Park, Jong-Won;Jung, Dong-Soo
    • Journal of Applied Reliability
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    • v.12 no.3
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    • pp.201-213
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    • 2012
  • A gear type lubrication pump is an essential component of the powertrain and has a major role for supplying oil to the gears and bearings in automatic transmission with a hydraulic clutch. Therefore, the durability test code design of lubrication pump is very important to ensure the reliability of the entire transmission and the vehicle. In this study, the design process for the life testing of lubrication pump has been generalized by four steps. The four design steps of the life testing of lubrication pump consist of the configuration of load spectrum, rain flow counting and analysis of load level, the equivalent damage assessment and test code generation. In fact, the load spectrum should be obtained from the field operating condition but that kind of data is the top secret of manufacturers. This is not open to the public in general. So we could use the artificially simulated load spectrum instead of field obtained one and focused on the development of the general process for designing the life test of a gear type lubrication pump. Reliability goals for lubrication pump, pressure, torque, temperature and load spectrum, if present, as appropriate for the given test conditions, accelerated life testing for the lubrication pump can be designed by the developed design steps.

Development of a Design System for Multi-Stage Gear Drives (2nd Report : Development of a Generalized New Design Algortitm

  • Chong, Tae-Hyong;Inho Bae
    • International Journal of Precision Engineering and Manufacturing
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    • v.2 no.2
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    • pp.65-72
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    • 2001
  • The design of multi-stage gear drives is a time-consuming process, since on includes more complicated problems, which are not considered in the design of single-stage gear drives. The designer has th determine the number of reduction stages and the gear ratios of each reduction state. In addition, the design problems include not only the dimensional design but also the configuration design of gear drive elements. There is no definite rule and principle for these types of design problems. Thus the design practices largely depend on the sense and the experiences of the designer , and consequently result in undesirable design solution. We propose a new generalized design algorithm to support the designer at the preliminary design phase of multi-stage gear drives. The proposed design algorithm automates the design process by integrating the dimensional design and the configuration design process. The algorithm consists of four steps. In the first step, a designer determines the number of reduction stage. In the second step. gear ratios se chosen by using the random search method. In the third step, the values of basic design parameter are chosen by using the generate and test method. Then, the values of other dimension, such ad pitch diameter, outer diameter, and face width, are calculated for the configuration design in the final step. The strength and durability of a gear is guaranteed by the bending strength and the pitting resistance rating practices by using the AGMA rating formulas. In the final step, the configuration design is carried out b using the simulated annealing algorithm. The positions of gears and shafts are determined to minimize the geometrical volume(size) of a gearbox, while satisfying spatial constraints between them. These steps are carried out iteratively until a desirable solution is acquired. The propose design algorithm has been applied to the preliminary design of four-stage gear drives in order to validate the availability. The design solution have shown considerably good results in both aspects of the dimensional and the configuration design.

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Transient EHL Analysis on Spur Gear Teeth with Consideration of Gear Kinematics

  • Koo, Young-Pil
    • Journal of Mechanical Science and Technology
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    • v.18 no.8
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    • pp.1319-1326
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    • 2004
  • Transient 3-dimensional elasto-hydrodynamic lubrication (EHL) analysis is performed on the contacting teeth surfaces of involute spur gears. Kinematics of the gear and the pinion are taken into account to get accurate geometric clearance around the EHL region of the contacting teeth. The surface pressure and film thickness distribution for the whole contact faces in a lubricated condition at several time steps are obtained through the analysis. Besides the pressure spike at the outlet region, a representative phenomenon in EHL regime, the pressure at the inlet region is slightly higher than that of the center region. The film thickness of transient condition is thicker than that of steady condition.

Analysis of Factors Affecting Fuel Consumption of Agricultural Tractor (농용 트랙터 연료소모량에 미치는 요인분석)

  • Park, Seok-Ho;Kim, Young-Jung;Im, Dong-Hyeok;Kim, Chung-Kill;Jang, Yang;Kim, Sung-Su
    • Journal of Biosystems Engineering
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    • v.35 no.3
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    • pp.151-157
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    • 2010
  • The objective of this study was to analyze the factors affecting on fuel consumption of agricultural tractor. According to the statistical analysis, fuel consumption of agricultural tractor was considerably influenced by kind of operation, throttle engine speed and gear steps of tractor but much less by kind of soil. Specific fuel consumption of the tractor in plowing, dry paddy tilling, wet paddy tilling and wet paddy levelling was 0.33~0.36, 0.30~0.45, 0.19~0.34, 0.28~0.39 L/$kW{\cdot}h$, respectively, and $CO_2$ emission was 0.36~0.45, 0.35~0.58, 0.22~0.42, 0.24~0.37 kg/$kW{\cdot}h$, respectively. Specific fuel consumption and $CO_2$ emission increased as throttle engine speed increased but reversely proportional with gear step of tractor, by which one can reduce fuel consumption and $CO_2$ emission with practicing of "Gear up & Throttle Down" technique in paddy operations.

Development of Design System for Multi-Stage Gear Drives Using Simulated Annealing Algorithm (시뮬레이티드 어닐링을 이용한 다단 치차장치의 설계 시스템 개발)

  • 정태형
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.464-469
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    • 1999
  • Recently, the need for designing multi-stage gear drive has been increased as the hear drives are used more in the applications with high-speed and small volume. The design of multi-stage gear drives includes not only dimensional design but also configuration design of various machine elements. Until now, however, the researches on the design of gear drives are mainly focused on the single-stage gear drives and the design practices for multi-stage gear drives, especially in configuration design activity, mainly depend on the experiences and 'sense' of the designer by trial and error. We propose a design algorithm to automate the dimension design and the configuration design of multi-stage gear drives. The design process consists of four steps. The number of stage should be determined in the first step. In second step, the gear ratios of each reduction stage are determined using random search, and the ratios are basic input for the dimension design of gears, which is performed by the exhaustive search in third step. The designs of gears are guaranteed by the pitting resistance and bending strength rating practices by AGMA rating formulas. In configuration design, the positions of gears are determined to minimize the volume of gearbox using simulated annealing algorithm. The effectiveness of the algorithm is assured by the design example of a 4-stage gear drive.

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Development of a Design System for Multi-Stage Gear Drives (2nd Report: Development of a Generalized New Design Algorithm) (다단 치차장치 설계 시스템 개발에 관한 연구(제 2보: 일반화된 신설계 알고리즘의 개발))

  • Chong, Tae-Hyong;Bae, In-Ho;Park, Gyung-Jin
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.10
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    • pp.192-199
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    • 2000
  • The design of multi-stage gear drives is a time-consuming process because it includes more complicated problems, which are not considered in the design of single-stage gear drives. The designer has no determine the number of reduction stages and the gear ratios of each reduction stage. In addition, the design problems include not only dimensional design but also configuration design of gear drive elements. There is no definite rule or principle for these types of design problems. Thus the design practices largely depend on the sense and the experiences of the designer, and consequently result in undesirable design solution. A new and generalized design algorithm has been proposed to support the designer at the preliminary phase of the design of multi-stage gear drives. The proposed design algorithm automates the design process by integrating the dimensional design and the configuration design process. The algorithm consists of four steps. In the first step, the user determines the number of reduction stages. In the second step, gear ratios of every stage are chosen using the random search method. The values of the basic design parameters of a gear are chose in the third step by using the generate and test method. Then the values of the dimensions, such as pitch diameter, outer diameter and face width, are calculated for the configuration design in the next step. The strength and durability of each gear is guaranteed by the bending strength and the pitting resistance rating practices by using AGMA rating formulas. In the final step, the configuration design is carried out using simulated annealing algorithm. The positions of gears and shafts are determined to minimize the geometrical volume (size) of a gearbox while avoiding interferences between them. These steps are carried out iteratively until a desirable solution is acquired. The proposed design algorithm is applied to the preliminary design of four-stage gear drives in order to validate the availability. The design solution has considerably good results in both aspects of the dimensional and the configuration design.

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Precision Cold Forging of Spur Gear Using the Alloy Steel (합금강을 이용한 스퍼기어의 정밀 냉간 단조)

  • Choi, J.C.;Choi, Y.
    • Transactions of Materials Processing
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    • v.6 no.6
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    • pp.500-507
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    • 1997
  • The conventional closed-die forgings had been applied to the forging of spur gears. But the forgings require high forging-pressure. In this paper, new precision forging technology have been developed. The developed technology is two steps forging process. Good shaped products are forged successfully with lower forging-pressure than those of conventional forging. The accuracy of the forged spur gear obtained by new precision forging technology is set nearly equal to that of cut spur gear of fourth and fifth class in Korean industrial standard.

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A Study of Effects of the Helical Angle Directions of Planetary Gear Sets on the Axial Forces on Thrust Bearings in an Automatic Transmission (자동변속기 적용 유성기어의 헬릭스 각 방향에 의한 쓰러스트 베어링 작용 축 하중 연구)

  • Kwon, Hyun Sik
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.3
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    • pp.92-99
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    • 2021
  • An automatic transmission, which consists of several decks of planetary gear sets, provides multiple speed and torque ratios by actuating brakes and clutches (mechanical friction components) for connecting central members of the planetary gear sets. The gear set consists of the sun gear, the ring gear, and the carrier supporting multiple planet gears with pin shafts. In designing a new automatic transmission, there are many steps to design and analyze: gears, brakes and clutches, shafts, and other mechanical components. Among them, selecting thrust bearings that not only allow the relative rotation of the central members and other mechanical components but also support axial forces coming from them is important; doing so yields superior driving performance and better fuel efficiency. In selecting thrust bearings, the magnitude of axial forces on them is a critical factor that affects their bearing size and performance; its results are systematically related to the direction of the helical angle of each planetary gear set (a geometric design profile). This research presents the effects of the helical angle direction on the axial forces acting on thrust bearings in an automatic transmission consisting of planetary gear sets. A model transmission was built by analyzing kinematics and power flows and by designing planetary gear sets. The results of the axial forces on thrust bearings were analyzed for all combinations of helix angle directions of the planetary gear sets.

Precision Cold Forging of Spur Gear Using the Alloy Steel (합금강을 이용한 스퍼기어의 정밀 냉간 단조)

  • Choi, J.C.;Choi, Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.172-175
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    • 1997
  • The conventional closed-die forgings had been applied to the forging of spur gears. But the forgings require high forging-pressure. In this paper, new precision forging technology have been developed. The developed technology is two steps forging process. Good shaped products are forged successfully with lower forging-pressure than those of conventional forging

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Non-Steady Elastohydrodynamic Lubrication Analysis on Spur Gear Teeth

  • Kim, H.J.;Kim, Y.D.;Koo, Y.P.;Choi, H.C.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.81-82
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    • 2002
  • A non-steady 3-dimensional elastohydrodynamic lubrication analysis was performed on the contacting teeth surfaces of involute spur gears. Kinematics of the gear and the pinion were taken into account to get accurate geometric clearance around the elastohydrodynamic lubrication region of the contacting teeth. Pressure and film thickness distribution for the whole contacting faces in lubricated condition at several time steps were obtained through the analysis. Besides the pressure spike at the outlet region, a representative phenomenon in elastohydrodynamic lubrication regime, the pressure at the inlet region was slight higher than that of the center region. The film thickness of non-steady condition was thicker than that of steady condition.

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