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Properties of a three disc cycloid gear as a result of bench test

Pawelski Z., Zdziennicki Z., Uszpolewicz G.

Journal of KONES

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2018

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Vol. 25, No. 2

269--280

EN

The most common design solution are cycloidal gearboxes with two discs, in which the reaction forces of bearings from the working discs create a bending moment on the high-speed input shaft, additionally affecting bearings. In the article are presented the results of tests of the cycloid gear prototype with three discs. Instead of the second disc, the introduction of two side discs, 1800 from the centre disc, allows you to reduce this moment to zero. To compensate for the unbalance of the shaft, the side discs have half the width of the centre disc. Each disc works with its own, separate set of bronze rollers, separated by Teflon washers, which should reduce the friction forces. In the article are presented the results of the tests of the cycloid gear prototype determining basic parameters such as efficiency, torque fluctuations on the input and output shaft, housing vibrations in three directions. FFT analysis of registered parameters showed high compliance of the designated frequencies for different measured signals. The assumed advantages, i.e. high efficiency and low vibration level in the tested range, were confirmed. The results are presented in the form of three-dimensional graphs as functions of speed and torque. High efficiency (80-90) % was obtained for load moments above 150 Nm, which is practically independent of the rotational speed with which the cycloid gearing works. The oil temperature during the tests was maintained in the range of 36oC ± 2oC. The maximal torque of the cycloidal gear was 500 Nm.

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Modelling of a permanent magnet motor with an inverter in a drive system of a car. Part 2

Pawelski Z., Uszpolewicz G.

Journal of KONES

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2018

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Vol. 25, No. 4

325--335

EN

The article presents a mathematical model of a permanent magnet motor, powered by a three-phase source of sinusoidal voltage, and a control method. Cooperation between numerical integration algorithms in the differential equation system of the motor and an inverter has been verified. The results of numerical simulations are presented in a graphic form. This article is an extension of the publication [12], in which a model of a drive system was proposed, consisting of: a battery, a supercapacitor and a method of controlling these energy sources during a driving cycle of a vehicle. For vector control, the mathematical model of a synchronous machine in the dq coordinate system is the most common one. The most important feature of this control method is the fact that the iq component of the rotor current vector determines the value of motor torque, and the component id – the value of magnetic flux. In the article, the emphasis is put on how inverters work. Their basic task is to generate such currents iabc or voltages uabc to obtain torque without ripples. It leads to development of different control concepts for achieving this goal, which are related to the modelling of magnetic fluxes in a stator and in an inverter.

3

Impact of the geometry accuracy of the cycloidal gear output shaft with pins of the efficiency and vibrations

Pawelski Z., Zdziennicki Z., Uszpolewicz G., Mitukiewicz G., Ormezowski J.

Journal of KONES

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2018

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Vol. 25, No. 4

337--345

EN

Cycloidal gear is characterized by [2]: – Large ratio (up to 171:1) from one stage of reduction, which minimizes the weight and dimensions of the reducer. – Minimizing the centrifugal forces as the only high-speed element is the input shaft with an eccentric bearing. – Minimizing internal clearance due to simultaneous meshing of a large number of teeth. In contrast to gears with involute teeth, 10-50% of teeth are found in cycloidal gears with simultaneous meshing. It depends on the size of the gear and the load. The minimum number of teeth engages when running in bulk. – Low noise and low vibration for large torques and variable speeds. – High efficiency in a wide range of loads, because rolling elements are used in every place responsible for the transfer of torque. – Permissible load up to 500% of the rated torque. All above mention point lead into long-term and trouble-free operation, however the above features require high accuracy. The article described comparison of efficiency, vibration and noise obtained for 3 cycloidal gear modules: 1. Two-disc gear with single rollers for both discs (Chmurawa prototype [1]). 2. Three-disc gearbox with separate rollers for each disc (new idea) with gear components: output shaft with pins, housing with rollers (wheel with internal tooting), and input shaft, made with the manual lathe. 3. The same three-disc gearbox with output shaft with pins made with the CNC. Different levels of accuracy and thus corresponding vibration patterns were obtained.

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Atesting capabilities of a new test rig, with a planetary gear unit examined as an example

Pawelski Z., Uszpolewicz G., Zdziennicki Z.

Archiwum Motoryzacji

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2017

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Vol. 77, nr 3

111--132

EN

The article describes a test rig built at the Department of Vehicles and Fundamentals of Machine Design, Lodz University of Technology (TUL), for static and dynamic examination of vehicle and machinery driveline components. Adequate installed power of the propulsion system and extensive instrumentation of the test rig makes it possible to examine various prototype mechanical transmission units with power capacities of up to several ten kilowatts and to carry out a broad spectrum of measurements with high accuracy. During the tests, such variables as vibrations in any direction, gear shaft speeds, torques, noise levels, and various oil parameters, e.g. temperature, moisture content, or ferromagnetic debris content, may be recorded. Additional equipment enables precise alignment of all the rotating parts in the test rig drive train and determination of oil viscosity before and after the test. An important feature of the test rig is a possibility of changing the drive direction without demounting the object under test. This can be done thanks to an inverter control system, which enables electric machine operation modes to be switched over from motor to generator and vice versa. In the subsequent part of the article, selected results of testing a planetary gear unit with a geometric gear ratio of 3.1372 have been presented, which include efficiency, FFT analysis of vibrations, and noise level data. The test results have confirmed the suitability of the test rig for multipurpose applications and for comprehensive diagnosing of driveline components.

PL

W artykule opisano stanowisko do statycznych i dynamicznych badań podzespołów układów napędowych zbudowane w Katedrze Pojazdów i Podstaw Budowy Maszyn Politechniki Łódzkiej. Moc urządzeń napędowych zainstalowana na stanowisku, pozwala na badanie różnych prototypów przekładni mechanicznych o mocach do kilkudziesięciu kilowatów a bogate jego oprzyrządowanie umożliwia przeprowadzenie szerokiego spektrum pomiarów z wysoką dokładnością. W trakcie badań rejestrowane są takie zmienne jak drgania w dowolnym kierunku, prędkości obrotowe wałów przekładni, momenty obrotowe, poziom hałasu oraz parametry oleju takie jak temperatura, zawartość wilgoci i ścieru ferromagnetycznego. Dodatkowe wyposażenie umożliwia precyzyjne ustawienie współosiowe wszystkich elementów wirujących w linii napędowej stanowiska oraz określenie lepkości oleju przed i po badaniach. Istotną cechą stanowiska jest możliwość zamiany kierunku napędu bez demontażu badanego obiektu, co jest możliwe dzięki układowi sterowania falownikami umożliwiającemu zmianę charakteru pracy maszyn elektrycznych z silnika na generator i odwrotnie. W dalszej części przedstawiono wybrane wyniki badań przekładni planetarnej o przełożeniu kinematycznym 3,1372: określenie sprawności, analizę częstotliwościową drgań oraz poziom hałasu. Badania potwierdziły uniwersalność stanowiska i możliwość wszechstronnego diagnozowania podzespołów układów napędowych.