• Tribology and Lubricants
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• 제34권6호
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• pp.325-331
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• 2018

Automobiles and systems requiring high gear ratios and high power densities generally use worm gears. In particular, as worm gears have a small volume and self-locking function, home appliances such as refrigerators and washers consist of worm gears. We can classify worm gears into cylindrical worms and rectangular worms. According to the AGMA standard, there are four types of cylindrical worms, ZA, ZN, ZK and ZI, depending on the machining of the worm shaft. It is preferable to use a ZI-type worm shaft, which is a combination of a worm wheel having an involute helical tooth surface and a conjugate tooth surface. However, in many cases, industries mostly use ZK, ZN, and ZA worm shafts because of the ease of processing. This paper presents numerical approaches to produce ZI and ZA worm surfaces and worm wheel. For the analysis of the transmission error of a worm gear system, this study (1) generates surface profile functions of ZI profile worm gear and worm shaft based on the common rack theory, (2) adopts the Newton-Raphson method for the analysis of the gear surface contact condition, and (3) presents and compares the corresponding transmission errors of ZI and ZA worm gears.

• 동력기계공학회지
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• 제11권4호
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• pp.65-71
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• 2007

According to the survey, abnormal condition of the system is the main source for interrupting an elevator service, especially faults in worm gears used for the traction machine. Worm gear is popularly used in traction machine for middle and low speed elevators. Elevators need high reliability and stability, because they are closely related to human life. Usually, traction machine is applied to drive the elevators that have height about 35 m and it is an important mechanical unit for riding quality in elevators. There are some research results about types of vibration fault for worm gear in International Association Elevator Engineers (IAEE). But this study concerns with diagnosis of various faults in elevator worm gear using vibration signal. The analysis of fault characteristics is compared with previous researches in traction machine.

• 동력기계공학회지
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• 제20권1호
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• pp.57-62
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• 2016

In this study, design the core part of the driving of the robot. The power of the driving is window motor for automobiles obtained by using a method of directly to the motor shaft of the worm gear type. The decelerator consists of a worm gear to receive power from the motor shaft, Helical gear contact to worm gear, a pinion gear to be connected in line with the helical gear, and an output shaft to be engaged to the pinion gear. Drive system by using the power from the motor shaft based on the deceleration gear designed by the gear ratio set by the gear teeth increases the torque.

• 한국자동차공학회논문집
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• 제22권1호
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• pp.77-84
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• 2014

The worm gear is used in the motor drive system of automotive CVVL because of its compactness and self-locking ability. A ZK worm and an involute helical gear can be meshed in order to reduce production cost. However, the gearing is not suitable for the reliability and the NVH problem. To improve the dynamic performances, an optimal design process is considered. The transmission error is calculated theoretically and minimized with the several gear design parameters. An inequality condition such as the teeth interference elimination is added.

• 한국융합학회논문지
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• 제2권2호
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• pp.27-34
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• 2011

본 연구는 호빙 가공공정 없이 워엄 휠 기어 형상을 만들기 위한 워엄 휠의 개발을 위한 제품을 만드는 것이다. 호빙 가공 공정이 없기 때문에, 증가된 생산성과 등가의 품질을 가지는 플라스틱 워엄 휠이 결국 만들어지게 된다. 그 결과, 이 제품은 현대 모비스, 만도, TRW, KOYO/NSK/Showa(Japan), Delphai(Amercia)에 판매 될 것이다. 핵심 기술 및 전략은 다음과 같다. 워엄 휠의 성형을 위한 기술 보호는 최근 "헬리컬 기어(No. 10-2008-0105908) 성형"이 특허 공정으로 되어 있다. 나아가, "보스 삽입을 위한 위치 결정을 위한 성형 시스템"을 위한 특허 절차가 준비 중이다. 기어 기계가공 절차 없이 호빙 머신에 기어 성형 절차로서, 무엇보다 먼저, 기어를 만드는 코어 개발 기술이 주된 주제이다. 따라서, 코어 및 성형 기초가 초기 순서로 개발되지 않아서, 현재 개발되는 워엄 휠의 경우, 기어는 이차적으로 호빙 M/C로 기계가공 된다. 최종적으로는, 성형 기초 구조체를 위한 특허가 본 연구결과로 만들어질 예정이다.

• 한국기계가공학회지
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• 제17권1호
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• pp.1-7
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• 2018

We aimed to develop a high quality 3.5 ton class swing reducer by studying the efficiency improvement of the reducer through the optimum design and performance evaluation of the assembled, high efficiency, lightweight 3.5 ton swing reducer. Based on the optimal design of the worm and worm wheel, the optimal manufacturing method of the worm wheel, the optimized casing design, and the optimum design of the output pinion, Respectively. Therefore, in this paper, to improve the efficiency of the worm gear reducer system, we will develop the manufacturing technology and verify the mass production by combining the manufacturing process design, processing and assembling technology according to the optimization design. We have conducted research to realize mass production by product verification such as product efficiency, reliability and durability according to optimal design of worm gear reducer.

• Journal of Biosystems Engineering
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• 제22권4호
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• pp.497-502
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• 1997

Automation facilities of greenhouses have been continuously developed. However, the conventional two-stage worm gear reducer reveals some problems, including low transmission efficiency. The worm gear reducer also have some difficulties in manufacturing and short life. Therefore, this study was performed to develop a planetary gear reducer, having a high Sear reduction ratio and high torque transmission efficiency. The planetary gear system consisted of a fixed ring gear and a 2-teeth differential ring gear turning slow, as the planetary pinion orbits fast around the fixed ring gear. The developed gear system can achieve a high speed reduction rate at one stage. The reducing system was employed to the greenhouse ventilation system. The reducer has the transmission efficiency of 70.5%, 2∼3 times longer life time, and twofold roll-up torque at an affordable price, comparing with conventional reducers. This reducer can be also applied to many industrial equipments, such as industrial crane, hoist, elevator and gondola etc.

• 한국기계기술학회지
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• 제13권4호
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• pp.137-141
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• 2011

Driving mechanism, the central part of a robot, was designed in this study. Power for the motive drive was acquired by directly connecting the motor shaft in worm shape of the low-end DC motor, car window motor, to a decelerator. The decelerator consists of a worm gear to receive power from the motor shaft, a pinion gear to be connected in line with the worm gear, and an output shaft to be engaged to the pinion gear. Motion driving is achieved by the power from the motor shaft with the designed gears, transferred to the deceleration mechanism and to the output gear.

• 한국산업융합학회 논문집
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• 제24권5호
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• pp.589-596
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• 2021

In this study, the optimum gating system was designed, and the two zinc alloy worm gears were manufactured in single process by applying a symmetrical gating system with 2 runners. The SRG ratio is set to 1 : 0.9 : 0.6, and the cross-sectional shapes such as sprue, runner and gate are designed. In order to determine whether the design of the gating system is appropriate, casting analysis was carried out. It takes 4.380 s to charge the casting 100%, 0.55 to 0.6 m/s at the gates and solidification begins after the casting is fully charged. The amount of air entrapment is 2% in the left gear and 6% in the right gear. Hot spots occurred in the center hole of the gear, and pores were found to occur around the upper part of the hole. Therefore, the design of the casting method is suitable for worm gears. CT analysis showed that all parts of worm gear were distributed with fine pores and some coarse pores were distributed around the central hole of worm gear. The yield strength and tensile strength were 220 MPa, 285 MPa, and the elongation rate was 8%. Vickers hardness is 82 HV.

• 한국자동차공학회논문집
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• 제5권1호
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• pp.207-216
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• 1997

We developed the durability estimation and design systems to minimize the volume, considering the durability, efficiency, and design requirements of worm gears. That is, we consider each kind of factors affecting on durability on the basis of AGMA Standard for the cylindrical and double-enveloping worm gears. We also estimate input power on the basis of wear and durability, bending strength and deflection of worm shaft, and we developed the durability estimation and design systems of power transmission worm gears introducing the optimal design method on the personal computer to be easily used in field. Also, we developed a method which converts the design variables obtained from the optimal design method to integer values(number of worm threads, number of worm threads, number of worm wheel teeth, etc.,) to be used in real design and production. The developed durability estimation and design method can be easily applied to the design of worm gears used as power transmission devices in machineries and is expected to be used for weight minimization of worm gear unit.