Planetary Type Research Articles

Finite element analysis and experimental research on multi-wheel planetary intermittent type spinning mechanism for internally-externally toothed parts with thin-wall cup-shaped

In this paper, a multi-wheel planetary intermittent type spinning process was investigated through finite element analysis(FEA) and process experiment. The spinning deformation mechanism of cup-shaped internally-externally toothed parts was studied by simulating the planetary spinning process. The distribution of the transient stresses in the contact zones between the roller and blank, and the equivalent plastic strains after spinning were analyzed. The location and causes of defects were determined through analyzing three-dimensional stress and equivalent strain. By comparing the distribution of workpiece thickness after spinning with the simulation result, it has indicated that this research is favorable for developing the technological forming criterion to guide the practical manufacture processes.

Optical and Dielectric Properties of PMMA/α-Fe2O3–ZnO Nanocomposite Films

In this study, α-Fe2O3–ZnO mixed particles were incorporated into the poly methyl methacrylate (PMMA) matrix by using solvent casting process. In order to prepare a powder mixture, mechanical milling process was used. α-Fe2O3 synthesized by precipitation method and ZnO nanoparticles were mixed with same amount and milled with planetary type ball milling machine for 1 h. Morphological and structural examinations of the produced powders were conducted with scanning electron microscopy (SEM) and X-ray diffraction (XRD). Optical and dielectrical properties of composite materials produced with different amount of reinforcement (0.1 wt%, 0.5 wt% and 1.0 wt%) were examined by using UV–Vis spectrophotometry and vector network analyzer (VNA). It was observed that optical transmittance reduced with increasing reinforcement amount. Dielectric properties of produced pellet composites with 4 mm thickness were conducted between 70 and 110 GHz and the results showed that the real and complex permittivity and dielectric loss values of PMMA/α-Fe2O3 is higher than those of neat PMMA, PMMA/ZnO and PMMA/α-Fe2O3–ZnO.

Periodic Motion and Stability of Gravitational Planar Triple Systems

The stability of gravitational triple systems is a well known problem in celestial mechanics. The basic model used is the general three body problem. Many criteria estimated from the integrals of motion and zero velocity curves or from purely numerical simulations have been given in literature. In this paper we propose a different approach for the study of stability of triple systems based on the numerical computation of manifolds of periodic orbits and their linear stability. Such an approach has been used for the study of two-planet exosolar systems but here, applying the method of continuation with respect to the masses, we refer to systems where all bodies can have similar mass values. In the present work we apply the proposed approach by starting from the circular family of periodic orbits, which is known to exist for the planetary type problem, and we restrict our computations to the case of two equal masses. By considering that the system has a hierarchical structure, the constructed manifold of periodic solutions can be projected on a plane defined by the relative distance and the relative mass of the system. On such a plane a stability map can be constructed showing the stability limits on the manifold of periodic orbits.

Design and bearing characteristics of planetary roller screws based on aerospace high-load conditions

Under the background of the rapid development of today’s aerospace industry, the bearing characteristics of planetary roller screw drive under high overload conditions are studied. Designing a high-load, high-performance precision planetary roller screw drive is of practical and significant. An axially spaced RV type planetary roller screw with a single nut is designed under aerospace conditions. Under the conditions of the aerospace working load and efficiency, the parameters and structures of the planetary roller screw are completed. Based on this, the bearing characteristics of the planetary roller screw are studied and the equivalent finite element model of the planetary roller screw is analyzed. Those analyses include stress and strain, elastic–plastic properties, transmission efficiency, and dynamic load capacity. The results show that the design of planetary roller screw meets the design requirements for aerospace conditions. And the results can provide a basis for the design and manufacture of planetary roller screws under high loads.

Modeling of Epitaxial Silicon Growth From the DCS-H2-HCl System in a Large Scale CVD Reactor

Multi-wafer planetary type chemical vapor deposition (CVD) reactors are widely used in thin film growth and suitable for large scale production. In this paper, numerical modeling has been carried out to simulate transport phenomena and epitaxial silicon growth in a planetary CVD reactor for the SiH2Cl2–H2–HCl system. A chemical reaction model using temperature dependent reaction rate is proposed and validated using experimental data. Based on the model, the effect of various operation conditions such as satellite rotational speed, species concentration, operating temperature and pressure is considered to determine the key factor influencing the growth rate and uniformity. The results reveal that the growth rate and uniformity are strongly related to total flow rate, species concentration and operating pressure, but are not affected by rotational speed of the satellite in case of high flow rates. Growth rates are found to be increased from 0.02 $\mu \text{m}$ /min at operating pressure of 10 torr to approximately 0.16 $\mu \text{m}$ /min at 150 torr. Growth deposition non-uniformity decreases from 80% for total flow rate of 460 slm to 13% for total flow rate of 46 slm.

Influence of Milling Time on Structural and Microstructural Parameters of Ni50Ti50 Prepared by Mechanical Alloying Using Rietveld Analysis

Nanostructured Ni50Ti50 powders were prepared by mechanical alloying from elemental Ni and Ti micrometer-sized powders, using a planetary ball mill type Fritsch Pulverisette 7. In this study, the effect of milling time on the evolution of structural and microstructural parameters is investigated. Through Rietveld refinements of X-ray diffraction patterns, phase composition and structural/microstructural parameters such as lattice parameters, average crystallite size L, microstrain ε21/2, and stacking faults probability (SFP) in the frame of MAUD software have been obtained. For prolonged milling time, a mixture of amorphous phase, NiTi-martensite (B19′), and NiTi-austenite (B2) phases, in addition to FCC-Ni(Ti) and HCP-Ti(Ni) solid solutions, is formed. The crystallite size decreases to the nanometer scale while the internal strain increases. It is observed that, for longer milling time, plastic deformations introduce a large amount of stacking faults in HCP-Ti(Ni) rather than in FCC-Ni(Ti), which are mainly responsible for the observed large amount of the amorphous phase.

Bi-Abundance Ionisation Structure of the Wolf–Rayet Planetary Nebula PB 8

AbstractThe planetary nebula PB 8 around a [WN/WC]-hybrid central star is one of planetary nebulae with moderate abundance discrepancy factors (ADFs ~ 2–3), which could be an indication of a tiny fraction of metal-rich inclusions embedded in the nebula (bi-abundance). In this work, we have constructed photoionisation models to reproduce the optical and infrared observations of the planetary nebula PB 8 using a non-LTE stellar model atmosphere ionising source. A chemically homogeneous model initially used cannot predict the optical recombination lines. However, a bi-abundance model provides a better fit to most of the observed optical recombination lines from N and O ions. The metal-rich inclusions in the bi-abundance model occupy 5.6% of the total volume of the nebula, and are roughly 1.7 times cooler and denser than the mean values of the surrounding nebula. The N/H and O/H abundance ratios in the metal-rich inclusions are ~1.0 and 1.7 dex larger than the diffuse warm nebula, respectively. To reproduce the Spitzer spectral energy distribution of PB 8, dust grains with a dust-to-gas ratio of 0.01 (by mass) were also included. It is found that the presence of metal-rich inclusions can explain the heavy element optical recombination lines, while a dual-dust chemistry with different grain species and discrete grain sizes likely produces the infrared continuum of this planetary nebula. This study demonstrates that the bi-abundance hypothesis, which was examined in a few planetary nebulae with large abundance discrepancies (ADFs > 10), could also be applied to those typical planetary nebulae with moderate abundance discrepancies.

Characterization of Ball Milled Al-Al2O3 sub-micron Composites

The purpose of this study is to investigate properties of the composite powders produced by ball milling process. Different weight ratio of high purity Al2O3 powders were added to the Al matrix as reinforcing element. Ball milling process was conducted by a planetary type ball mill with WC milling balls and vial at constant parameters like rotating speed, time, Ball-to-Powder ratio and Process Control Agent. Samples that taken from the powder mixtureby various time intervals were analyzed by SEM, XRD and BET surface area and porosity measurement systems.

Laser surface treatment of S235JRC carbon steel with Co2B nanocrystals

Abstract In this study, Co2B nanocrystals, which were synthesized in a planetary type mill by using the mechanochemical method, were pre-coated on the surface of S235JRC low carbon steel substrates, and then the surfaces were clad using a CO2 laser. In the experiments, laser scan speed was kept constant and laser power was specified as the variable parameter. The microstructure and phases of the coatings were investigated by using X-ray diffractometry, scanning electron microscopy, and optical microscopy. The mechanical properties of the coatings were characterized using micro-hardness, ball-on-disc wear, and scratch testing. The thickness of the coatings depending on the laser power was measured in the range 35–71 μm. The hardness and the wear resistance of the coatings were approximately 3 times higher compared to the base metal due to FeN0.0760, Fe15.1C, FeCo, and B2C5N2 phases of the coatings. The most durable coatings against wear were obtained at 174 W and 220 W laser powers.

Effect of silver nanoparticles on the microstructure and mechanical properties of alumina ceramics

ABSTRACTIn this work, the effect of additions of silver nanoparticles on the microstructure and mechanical properties of alumina-based ceramic was studied. The processing method for the manufacturing of alumina/silver composites imply high energy mechanical milling in a planetary type mill, cold uniaxial compaction and pressureless sintering in an inert atmosphere at 1500°C for 2 h. From the results after the milling step, approximately 45% of the powders have a particle size less than 1 μm. The microstructure observed by SEM is very fine and homogenous; the presence of silver apparently inhibits the grain growth of the alumina. With respect to mechanical properties, increases of the silver content in the matrix causes decrease of Young’s modulus and flexural strength of the composite obtained in 1.5 and 4.6%, respectively. On the other hand, the presence of silver greatly enhances the fracture toughness of alumina, from an increase of 4.2 MPa m−0.5 for monolithic alumina to 10 MPa m−0.5 for alumina with silver additions of 2 wt- %, representing an improvement of 138% in toughness of alumina. Lastly, hardness for this same sample was incremented in 12%.

Study on Nonlinear Dynamic Characteristics of 2K-H Planetary Gear System

A 2K-H type planetary gear reducer with involute spur gear is adopted as the research object. Considering the time-varying meshing stiffness, the time-varying backlash of the gear meshing and the time varying pressure angle and other nonlinear factors, the lateral-torsional-swing coupled nonlinear dynamic model of the planetary gear transmission system is established. According to the equations of Lagrange, the dynamic differential equations are derived. By introducing the state variable, the second-order differential equation of the coupled system is reduced to the first-order differential equation. The fifth-order step-varying adaptive Runge-Kutta numerical integration method is used to solve the dynamic equation. Compared with the previous dynamic models, this nonlinear dynamic model for the planetary gear transmission system is more closely to the practical operating conditions of the transmission system, which has laid a foundation for further evaluating the dynamic characteristics of the planetary gear transmission system in the future

Characterization of Al Matrix SiC Reinforced Sub-Micron Composites Produced by Mechanical Alloying

In this study, properties of the aluminum matrix silicon carbide reinforced sub-micron composite powders produced by mechanical alloying were investigated. High purity Al and SiC powders were used as initial powders. To investigate the effect of SiC quantity 5, 10, 15 and 20% weight ratio of SiC particles were added to the aluminum matrix. Milling operations were conducted at 250 rpm under high purity argon atmosphere for 120 h by planetary type ball mill. Milling balls and vial were made of tungsten carbide. The milling system stopped for by various time intervals and samples were taken from the powder mixture. After milling operations taken samples were analyzed by SEM, XRD and BET surface area and porosity measurement systems.

Method for Deriving Carboxymethyl Cellulose

<p>Chemical conversions proceeding in solid substances under mechanical effects are of great practical importance. At solid-phase mechanochemical interaction of powder cellulose and rice husks with a carboxymethylation agent, i.e. sodium monochloracetate, one obtained a product, the composition and properties of which are similar to commercial carboxymethyl cellulose. The given products were synthesized using laboratory microgrinder of a planetary type MA-1. Carboxymethyl cellulose obtained from powder cellulose is water-soluble product. Solubility of carboxymethyl cellulose synthesized from rice husks is about 80-95%. Viscosity of 5% aqueous solutions of the products from powder cellulose is about 2-5 mPa⋅s and viscosity of 10% aqueous solutions of the products from rice husks is about 4-6 mPa⋅s. It corresponds to viscosity of 1% solution of the commercial carboxymethyl cellulose. Carboxymethyl cellulose, obtained from powder cellulose and rice husks, represents a cheap product for petroleum, gas and building branches. Application of efficient and ecologically convenient solid-phase mechanochemical technology of carboxymethylation cellulose-containing products allows using accessible cellulose-containing scraps as raw material without their preliminary preparation and clearing. One can use carboxymethyl cellulose obtained by the solid-phase technology developed to control viscosity of water-based drilling fluids. Solubility and viscosity of these products depend on parameters of the processing and are compared to similar properties of commercial carboxymethyl cellulose.</p>

Load distribution of planetary roller screw mechanism and its improvement approach

A model of load distribution over threads of planetary roller screw mechanism (PRSM) is developed according to the relationships of deformation compatibility and force equilibrium. In order to make the applied load of PRSM uniformly distributed over threads, an improvement approach is proposed, in which the parameters of thread form of roller and nut are redesigned, and the contact conditions of roller with screw and nut are changed to compensate the axial accumulative deformation of shaft sections of screw and nut. A typical planetary roller screw mechanism is taken as example to analyze the load distribution, and the effects of installation configurations, load conditions and thread form parameters on load distribution are studied. Furthermore, the improvement approach is applied to the PRSM, and it is proved to be beneficial to reach uniform load distribution over threads.

Innovation design and experiment research on the N–N type planetary gear apparatus with small tooth number difference

The three high-performance indicators (low retrace tolerance, long life and low vibration) of N–N type planetary gear apparatus with small tooth number difference (abbrev “N–N–PGA”) are hardly achieved simultaneously until recently. At present, the root cause analysis (RCA) and TRIZ are considered to be comprehensive and systematic new theories for technological innovation, which provides a new way to figure out the conundrum existed in the N–N–PGA. In the present study, the “root cause” of the problem is proposed with the RCA approach and two contradictions existed in the N–N–PGA have been revealed: Harmful side effect and stability of composition; harmful side effect and durability of a moving object. Besides, two reasonable principles (“Dynamicity” and “Composite materials”) for the N–N–PGA design recommended by the TRIZ method are used to eliminate these contradictions. In addition, a prototype of the obtained new type N–N–PGA design is developed for experimental testing. The obtained result demonstrates the capability of the above method for obtaining low retrace tolerance, long life, and low vibration.

Elaboration and research of planetary precessional multiplier type K-H-V

The multiplier is an indispensable part of the micro hydropower plant and high power wind turbine. It helps to increase rotor low speeds limited by the water flow small velocity and by the relative big placement diameter of the blades that participate in the energy conversion. For example, the microhydrostation rotor's speed is (2 - 3) min'1 for water flow velocity V= (1...1,6) m/s and for blade placement diameter D = 4 m. Diversity of requirements forwarded by the beneficiaries of mechanical transmissions consists, in particular, in increasing reliability, efficiency and lifting capacity, and in reducing the mass and dimensions. It becomes more and more difficult to satisfy the mentioned demands by partial updating of traditional transmissions. The target problem can be solved with special effects by developing new types of multipliers based on precessional planetary transmissions with multiple gear, that were developed by the authors. Absolute multiplicity of precessional gear (up to 100% pairs of teeth simultaneously involved in gearing, compared to 5%-7% - in classical gearings) provides increased lifting capacity and small mass and dimensions. To mention that until now precessional planetary transmissions have been researched and applied mainly in reducers. Therefore it was necessary to carry out theoretical research to determine the geometrical parameters of the precessional gear that operates in multiplier mode. Also, it was necessary to develop new conceptual diagrams of precessional transmissions that function under multiplier regime. The majority of precessional planetary transmissions diagrams developed previously operate efficiently in reducer's regime. Depending on the structural diagram, precessional transmissions fall into two main types - K-H-V and 2K-H, from which a wide range of constructive solutions with wide kinematical and functional options that operate in multiplier regime.

An eight-speed rear transmission hub with a novel cam-type gear-shifting mechanism for bicycles

In this study, the conceptual design of an eight-speed rear transmission hub with a novel cam-type gear-shifting mechanism for bicycles is proposed. The main body of the transmission hub is a distributed-flow type planetary gear mechanism to provide eight forward gears. A design process for the embodiment design of a rotary-type gear-shifting mechanism is presented and illustrated. By combining the planetary gear mechanism with the gear-shifting mechanism, a novel eight-speed rear transmission hub for bicycles is generated. A 3-D printed prototype is also manufactured for further testing.

コイルばね型形状記憶合金素子を駆動源に用いた遊星歯車型SMA熱エンジンの試作とその動作特性

Sharp memory alloy (SMA) is one of the functional material which shows the shape memory effect and superelasticities. Since the shape recovery temperature of Ti-Ni system SMA is below at 373K, this alloy is expected the element of heat-engine driven by low-temperature thermal of energy. Previous SMA heat-engines have not became commonplace because of short product life. Last year, we reported the planetary geared type SMA heat-engine using SMA spiral spring actuator. This heat-engine targeted an improvement life cycle of SMA and reduction mechanism. However, spiral spring actuator did not operate by the energy of hot water when this engine was soused a hot water, for this type actuator was low output power. Therefore, we attempt to use SMA coil spring element for improving the planetary geared type SMA heat-engine. In this research, we investigated the operating characteristic of planetary geared type SMA heat-engine using SMA coil spring element.

粉砕棒を用いた土壌粉砕特性

This is the study to understand the pulverizing of soil by using the planetary type rotation machine. We are focusing on the process of soil pulverizing in a container by pulverizing rod. Akadama uses for the experiments. This is known as a common soil in Japan for agriculture. We measure the compressive strength and the water content in a soil to understand the physical property of soil. The pulverizing in a container is visualized. The results show that the rod moves in a container continuously during the planetary movement. The soil pulverized when the rod impacts from the longitudinal direction of rod.

대형 산업 차량에 적용되는 유성기어형 고감속 중간변속기 구현에 관한 연구

A high-speed reduction transfer case is usually employed by an excavator, wheel loader, or bulldozer. When powerful torque is required in the case of climbing steep roads or towing heavy equipment, the high-speed reduction mode of the gearbox is used. Generally, a transfer case using a spur gear type with a speed reduction system has a speed reduction ratio of 1 to 1 or 2 to 1. However, the structure of a transfer case achieved at a high speed of 1 to 1 and a low speed of 4.5 or under 5.5 to 1 with the speed reduction by use of a planetary gear type with a speed reduction system was proposed in this study. By employing a planetary gear type with a speed reduction system, the compact structure of the transfer case was achieved, and the impact or the partial defect of gear teeth was eliminated.