Elliptical Gears Research Articles

Tooth contact analysis of elliptical bevel gear with different misalignment

Considering the wide use of bevel gear, a new bevel gear type with variable transmission ratio has been proposed. Based on the manufacturing and generating theory of gear, the mathematical equations for the tooth surface of this gear type has been established with two different methods: lead crowning, which meets the commonly used industrial methods with higher efficiency, lower cost and the method with rack cutter shows much clear relationship of gear meshing process. The contact points and characteristics of transmission errors with different misalignment conditions have been presented. Also the feature of contact area on the tooth surface in a whole cycle was developed in this paper. Compared the contact results of elliptical bevel gear with curve face gear, the former has less misalignments sensitivity and better loaded capability.

New type of transverse moving box mechanism for pot seedling transplanting machine

The existing moving box mechanism pot seedling transplanting machine on the market moves too fast when the picked seedling is collected, which negatively impacts the seedling picking performance. In order to improve the performance, two types of variable speed continuous moving box schemes were designed in this study. The first scheme was to apply a spiral-gear moving box spiral shaft with sine curve characteristics in the box moving mechanism, whereas the second one was to change the circular gear in the moving box into an elliptical gear with a speed shifting transmission mechanism. The working mechanism of the mechanical structure was analyzed, and the kinematic model was established. A dynamic analysis of the slider mechanism was performed. A virtual prototype was established according to agronomic parameters, and the virtual prototype experiments were conducted in ADAMS. The physical prototype and the high-speed photography experiment were performed on the test bench of a transplanting machine frame. The theoretical analysis, virtual prototype and physical prototype test results were consistent, which verified the validity of the theoretical model, virtual prototype and physical prototype and ensured the feasibility of the system. Keywords: transplanting machine, rice transplanter, pot seedling, moving box mechanism, variable speed moving box, spiral shaft, elliptic gear DOI: 10.25165/j.ijabe.20181102.2867 Citation: Zhou M L, Hua Z Y, Wang J Y, Wang L, Zhao Y, Yin D Q. New type of transverse moving box mechanism for pot seedling transplanting machine. Int J Agric & Biol Eng, 2018; 11(2): 70–75.

New type of transverse moving box mechanism for pot seedling transplanting machine

The existing moving box mechanism pot seedling transplanting machine on the market moves too fast when the picked seedling is collected, which negatively impacts the seedling picking performance. In order to improve the performance, two types of variable speed continuous moving box schemes were designed in this study. The first scheme was to apply a spiral-gear moving box spiral shaft with sine curve characteristics in the box moving mechanism, whereas the second one was to change the circular gear in the moving box into an elliptical gear with a speed shifting transmission mechanism. The working mechanism of the mechanical structure was analyzed, and the kinematic model was established. A dynamic analysis of the slider mechanism was performed. A virtual prototype was established according to agronomic parameters, and the virtual prototype experiments were conducted in ADAMS. The physical prototype and the high-speed photography experiment were performed on the test bench of a transplanting machine frame. The theoretical analysis, virtual prototype and physical prototype test results were consistent, which verified the validity of the theoretical model, virtual prototype and physical prototype and ensured the feasibility of the system. Keywords: transplanting machine, rice transplanter, pot seedling, moving box mechanism, variable speed moving box, spiral shaft, elliptic gear DOI: 10.25165/j.ijabe.20181102.2867 Citation: Zhou M L, Hua Z Y, Wang J Y, Wang L, Zhao Y, Yin D Q. New type of transverse moving box mechanism for pot seedling transplanting machine. Int J Agric & Biol Eng, 2018; 11(2): 70–75.

Structural and kinematic analysis of a stirred tank planetary drive

Stirred tanks are used in many industries to intensify various physical and chemical processes. Currently, one of the most promising areas of research is the creation of rotationally reciprocating stirred tanks (RRST), which realize high mixing efficiency due to the difference in the velocities of the stirred liquid. As the actuator of RRST, we proposed to use a planetary gear with elliptical gears. Due to the variable transmission ratio of elliptical gearwheels, the rotationally reciprocating motion of the output shaft is ensured with rotational motion of the input shaft. We conducted a structural analysis of the planetary gear by means of the structural mathematical model of mechanisms and machines. A kinematic model of planetary gear has been constructed and studied, resulting in velocity analogue function of the mechanism output shaft.

Dynamics of rotationally reciprocating stirred tank with planetary actuator

The article investigates the dynamics of rotationally reciprocating stirred tank (RRST), whose actuator is the original planetary mechanism with elliptical gears. The dynamic model is constructed by reduction of driving forces, masses and moments to the reduction link (the input shaft of the actuator). The study of the resulting dynamic model was carried out by energy-mass method. As a result of the dynamic analysis we determined the necessary moment of driven forces and found the reduction link law of motion. The flywheel has been designed to ensure the required coefficient of rotation irregularity. Resulting dynamic model can be used for development and research of rotationally reciprocating stirred tanks.

Study of a vibrating propulsion system for marine vessels: Evaluation of the efficiency for a boat 13 m long

This paper illustrates recent advancements relative to a non-conventional propulsion system for boats and is based on two previous papers of the author presented at a conference (see Muscia, 2015a,b). The system does not consider propellers and utilizes the vibration generated by two or more pairs of counter rotating masses. The resultant of the centrifugal forces applies an alternate thrust to the hull that oscillates forward and backward along the longitudinal axis of the boat. The different hydrodynamic drag forces that oppose to the oscillation produce a prevalently forward motion of the vessel. The vibration that causes the motion can be suitably defined to maximize the forward displacement and the efficiency propulsion of the system. This result is obtained by using elliptical gears to rotate the counter rotating masses. The computation of the propulsion efficiency is based on a suitable physical mathematical model. Correlations between numerical experiments on models and possible full scale application are discussed. Some remarks in relation to practical applications and critical issues of the propulsive solution are illustrated. The results have been obtained with reference to a CAD model of a real boat already manufactured whose length is approximately equal to 13 m.

Optimal Design and Development of a Double-Crank Potted Rice Seedling Transplanting Mechanism

<abstract> <b><sc>Abstract.</sc></b> This study invented a simple-type potted rice seedling transplanting mechanism based on elliptical gears in combination with a double-crank five-bar mechanism. A reliable seedling picking and planting mechanism is proposed. The optimal design requirements of the transplanting mechanism, imitating manual transplanting of potted rice seedlings, were analyzed. The working principles of a theoretical model and kinematic characteristics of the transplanting mechanism were analyzed. Computer-aided analysis and optimization software based on Visual Basic 6.0 was developed and used to obtain a set of trajectory and attitude parameters that satisfy the transplanting operation requirements by the human-computer interactive technique. The optimized parameters were used for virtual manufacturing and simulation testing of the transplanting mechanism. The transplanting mechanism was subjected to high-speed photography bench tests by idling and seedling picking/planting verification. Prototype machine testing results were consistent with the theoretical analysis and virtual simulation results, verifying the validity and feasibility of each approach. The seedling picking test generated a high success rate of 98% at a carrier rotation speed of 100 rpm. Field tests of the prototype machine revealed success, and the transplanting process met the requirements of potted rice seedling transplanting.

Structure and kinematics of a planetary converter of the rotational motion into the reciprocating rotary motion

The problem of the structural synthesis of a mechanism for converting rotational motion into reciprocating rotary motion has been considered. In accordance with the synthesis conditions and the found solutions, a planetary mechanism with elliptical gears has been proposed and its kinematic analysis has been performed. It has been shown that the rocking angle and the asymmetry factor of the working stroke of the mechanism depend on the selection of the eccentricities of elliptical gears.

Meshing Condition and Kinematic Properties of non-circular Gear

The gearing with changing transmission gear ratio are used in the practice, even though the "standard" gearing with constant transmission gear ratio are used more often. The article examines the mesh conditions proposed in elliptical gears, as I speed and power ratios in this proposed gearings. The work is devoted to the analysis of these kinematic conditions in the proposed gearings and examines their differences from "standard" ring gear transmission with a constant transference number. The problem is solved for elliptical, eccentric gear with a continuously variable gear ratio to a range from 0.5 through 1 to 2.

Nuevo par de engranajes no circulares para reducir las aceleraciones del eje: Comparación con engranajes sinusoidales y elípticos

Se presenta un nuevo par de engranajes no circulares para obtener pequeñas aceleraciones del eje. Las formas de los engranajes pueden ser controladas dependiendo de la máxima aceleración y suavidad de los contornos requeridos. Se hace una comparación con engranajes elípticos y sinusoidales. Los resultados muestran que, para engranajes de dos lóbulos, los valores máximos y mínimos de los radios polares y de la relación de transmisión son iguales para los perfiles desarrollados y los sinusoidales, pero difieren para los elípticos. En contraste, los valores máximos de la aceleración angular, aceleración tangencial y ángulo de presión difieren. Se concluye que los nuevos perfiles proporcionan pequeñas aceleraciones angulares y tangenciales y menores ángulos de presión, excepto que los elípticos pueden exhibir menores aceleraciones tangenciales y ángulos de presión para grandes variaciones de la velocidad. Consecuentemente, las cargas y esfuerzos podrían ser menores. Esto podría resultar en sistemas más compactos.

305 楕円歯車装置の振動低減(機素潤滑設計I)

305 楕円歯車装置の振動低減(機素潤滑設計I)

Parameter Modification Guiding Optimization Design and Tests of a Rotary Transplanting Mechanism for Rice Plug Seedlings

A parameter modification guiding optimization method combined with fuzzy optimization was applied to improve the design of a rice plug seedling transplanting mechanism using a planetary gear train with elliptical gears and an incomplete non-circular gear. The laboratory kinematics was examined, and seedling transplanting tests were conducted. Based on the work principle analysis of the transplanting mechanism for rice plug seedlings, numerical kinematic objective functions were established using fuzzy objectives requirements such as transplanting trajectory and posture. Subordinate functions were determined to describe the objective functions. Then the optimization model of the mechanism was constructed which took the value of the subordinate degree of objective functions as the optimization objectives and the motion interference, height of the transplanting trajectory and mechanical structure as the constraint conditions. Parameter guiding optimization software based on Visual Basic 6.0 was developed independently to determine a set of better parameters for the mechanism, which can reduce dependence on expert experience and improve the efficiency of the design. The mechanism structure was designed, and a physical prototype was manufactured. A high-speed digital video camera and image processing technology were used to perform the kinematics bench tests to obtain the transplanting trajectory and posture of the mechanism. The consistency between the test results and theoretical results shows that the optimized mechanism can satisfy the transplanting requirements and that the design method and results are also accurate. Finally, rice seedling transplanting tests were conducted to verify the transplanting performance of the mechanism. The mechanism extracted 200 seedlings per minute per row with a success ratio of 95.89%; the mechanism also displayed a good effect in seedling pushing, showing that the mechanism could be applied in a practical machine.

Performance improvement of a vibration driven system for marine vessels

In this paper some developments concerning the possibility of generating a rectilinear motion of bodies partially or totally submerged subject to vibration, without the use of propellers, are presented. The motion is obtained by a device equipped with counterrotating masses installed in the vessel that vibrates along the longitudinal direction. The hull has a suitably shaped stern. The study considers an analysis for evaluating the energy that the propulsion system consumes in relation to its performances. A further objective was to maximize the speed of the system while keeping certain parameters unchanged relating to the equations of motion of the device and suitably allocating the counterrotating masses. This result is obtained by using elliptical gears to transmit the motion from the driving motor to a double pair of counterrotating masses. Such a solution allows us to reach the variability of the angular velocity of the counterrotating masses during each revolution in accordance with certain laws that maximize the thrust applied to the vessel preferentially along a direction in respect of the opposite one, all being equal. Finally, a formulation to compute the propulsive efficiency of the device study and the results of the numerical simulations carried out are illustrated.

Kinematic Analysis of Mechanism for Converting Rotational Motion into Reciprocating Rotational Motion

The authors propose a distinctive construction of the planetary mechanism with elliptical gears designed to convert rotational motion into reciprocating rotational (oscillating) one. We conducted a kinematic analysis of the mechanism, found the variation of the rotation angle, the angular velocity analogue and angular acceleration analogue of the mechanism output shaft. The developed mechanism is a classic planetary mechanism and is more reliable and compact in comparison with the lever and electromagnetic inverters.

Pitch curve design defects modification for non-circular bevel gear

A novel pitch curve design method for non-circular bevel gear is presented to simplify design of non-circular bevel gear. Pitch curve equation for non-circular bevel gear is deduced based on geometrical relationships between pitch cone surface of non-circular gear with parallel axis and spherical surface. Then, transmission ratio function is transformed into pitch curve design defects modification equation and mathematical expression between modification factor and pitch curve design parameters for non-circular bevel gear is derived. By using the expression, modification value of pitch curve can be determined rapidly and accurately. Simulation results for high-order elliptical bevel gear and Pascal curve bevel gear demonstrate that the proposed modification method can be applied to pitch curve design for other types of non-circular bevel gear. Design and verification efficiency for non-circular bevel gear are improved effectively by employing the proposed pitch curve design defects modification method.

Meshing principle and transmission analysis of a beveloid non-circular gear

To improve the stability and accuracy of non-circular gear transmission, a beveloid non-circular gear transmission scheme was developed to reduce the meshing impact and achieve backlash adjustment. When using the beveloid rack as the medium, the instantaneous contact line of the beveloid non-circular gear pair was shown to be a straight line, and the tooth surface was shown to be a ruled surface based on the transmission relationship between the rack centerline and the non-circular pitch curve. The zero-modification method was employed to develop the beveloid non-circular gear. Further, the generation method for the tooth profile of the modified non-circular gear was reviewed, and a digital solid model was developed for the beveloid non-circular gear. The physical contact simulation method was used to analyze the meshing backlash, and the influence of the axial displacement adjustment on the meshing backlash of the gear pair was obtained. By considering a pair of beveloid elliptic gears as an example, machining and transmission experiments were conducted, with results showing smooth gear-pair meshing and the anticipated backlash adjustment effect.

Tooth Profile Design and Kinematic Mechanism Simulation of Higher-order Elliptic Gears Based on MAPLE

Tooth Profile Design and Kinematic Mechanism Simulation of Higher-order Elliptic Gears Based on MAPLE

머신비전을 이용한 타원형 기어 검사 시스템에 관한 연구

타원형 기어는 오발 유량계에 사용되는 특수기어로써 타원형 모양에 의해 생긴 공간으로 물을 흘려보내 계측한다. 본 연구의 목적은 타원형 기어의 가공정도를 판단하고 불량을 가려내는 시스템을 머신비전을 이용하여 개발하는 것이다. 각종 산업분야에서 자동화가 확산되면서 머신미전의 수요는 늘고 있으며 업계전반의 생산공정 중 검사 공정에서 빼놓을 수 없는 인자가 되었다. 하지만 머신비전을 이용한 기어측정은 기어의 형상이 복잡하다는 이유로 잘 사용되지 않고 있다. 본 연구에서는 머신비전을 이용한 검사 프로그램으로 타원형 기어의 측정이 가능함을 보였으며 본 연구에서 설계한 타원형 기어의 가공정도를 판단할 수 있었다.

G1510404 楕円歯車を用いた簡易発電システムの開発([G151-04]ロボティクス・メカトロニクス部門一般セッション(4))

G1510404 楕円歯車を用いた簡易発電システムの開発([G151-04]ロボティクス・メカトロニクス部門一般セッション(4))

Transmission Theory and Typical Structure of Nonuniform Mechanism with Movable Teeth

Thanks to characteristics of compact structure, high load strength and good manufacture technics, the movable teeth transmission is expanded to the nonuniform transmission filed. The basic structure of nonconstant mechanism with movable rods is introduced. The profile formula of inner ring is constructed by simple cosine function and the outer is built under given transmission ratio. The continuous rotation condition, the transmission efficiency and the pressure angle among the rods, inner and outer rings of movable teeth device are discussed, which could provide theory base for its design. In addition, according to the initial position of movable rods, the mechanism is divided to two basic types. Ten different results are developed by fixing the rods, inner ring and outer ring separately. A movable teeth device with kinematic feature of elliptical gears is designed. An analysis of ten motion types of the mechanism is made under a set of same geometric datum. The simulation states that the nonuniform mechanism with movable teeth has bright application prospects by means of simple manufacturing process and transmission diversity.