• 드라이브 ㆍ 컨트롤
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• 제12권4호
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• pp.77-81
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• 2015

In general, the gears of mixer reducer for concrete mixer truck make use of the differential type planetary gear system to rotate mixer drum smoothly on the initial conditions. The planetary gear system is very important part of mixer reducer for concrete mixer truck because of strength problem. In the present study, calculating the gear specifications and analyzing the gear bending & compressive stresses of the differential planetary gear system for mixer reducer are necessary to analyze gear bending and compressive stresses confidently, for optimal design of the planetary gear system in respect to cost and reliability. As a result, analyzing actual gear bending and compressive stresses of the planetary gear system using Lewes & Hertz equation and verifying the calculated specifications of the planetary gear system, evaluate the results with the data of allowable bending and compressive stress from the Stress-No. of cycles curves of gears.

• Tribology and Lubricants
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• 제35권1호
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• pp.71-76
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• 2019

The differential planetary gear reducer as a main component of the concrete mixer driving mechanism requires a strong torque to mix concrete compounds. As this component is currently dependent on imports, it is necessary to develop it by conducting a study on vibration analysis and the resonance problem. The noise and vibration of a concrete mixer reducer increase owing to the transmission error of planetary gears, and the damage of components occurs owing to the problems in design and production. In this study, the tooth-passing frequency is calculated to evaluate the noise and vibration of a mixer reducer, and a fast Fourier transform (FFT) analysis is conducted through a vibration test using an acceleration sensor. The vibration of the reducer is measured at three points of input and output of the shaft and planetary gear housing with fixed and variable revolutions per minute. The operating conditions of gears and bearings are evaluated by performing the FFT analysis, and the resonance problem is verified. The results show that No. 1 pinion and ring gears revolve disproportionately. The amplitude values appear high, and the wear of tooth faces occur in tooth-passing frequencies and harmonic components of No. 1 and No. 2 pinion-ring gears. Therefore, we conclude that design changes in the reducer and a correction of tooth profiles are required.

• 드라이브 ㆍ 컨트롤
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• 제14권1호
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• pp.1-7
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• 2017

The power train of a concrete truck mixer reducer includes differential planetary gears to get a large reduction ratio for operating the mixer drum in a compact structure. These differential planetary gears are a very important part of the mixer reducer where strength problems are the main concern. Gear bending stress, gear compressive stress and scoring failure are the main concerns. Many failures in differential planetary gears are due to the insufficient gear strength and resonance problems caused by major excitation forces such as gear mating failure in the transmission. In the present study, where the excitation frequencies are the gear tooth passing frequencies of the mating gears, a Campbell diagram is used to calculate differential planetary gear critical speeds. Mode shapes and natural frequencies of the differential planetary gears are calculated by CATIA V5. These are used to predict gear resonance failures by comparing the working speed range with the critical speeds due to the gear transmission errors of the differential planetary gears.

• 대한기계학회논문집A
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• 제35권11호
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• pp.1399-1406
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• 2011

수처리 공정에는 반드시 교반기 전용 감속기가 사용된다. 본 연구에서는 사용 중의 누유를 방지하고 토크효율 향상을 위한 전용 누유방지형 감속기를 개발하였다. 설계 개선된 감속기 시제품을 개발하는데 있어서, CAD 및 CNC 고속가공기를 사용하여 실물모형(Mock up), 금형 등을 제작하였다. 특히 누유방지 구조인 감속기 시제품의 하부 하우징에 대한 구조적 안전성을 평가하고자 상용 유한요소 해석코드인 ALGOR 을 이용하였다. 해석 결과, 최대 von Mises 응력이 항복응력보다 낮은 123 N/$mm^2$ 으로 안전하였으며, 고유진동수는 650~700 Hz 이었다. 그리고 토크효율은 95.87%로서 이전 연구결과 (88.45%)에 비하여 약 8% 향상되었다. 소음 수준은 75 dB, 사용 중 누유 및 이상 소음은 발생하지 않았다. 따라서 항상된 감속기 시제품을 최적 설계하여 성공적으로 개발하였다.