scholarly journals PERSPECTIVES OF CYCLOID TRANSMISSION

2021 ◽  
Vol 05 (01) ◽  
pp. 72-80
Author(s):  
Alesker Aliyev ◽  
Aydan Qasimova
Keyword(s):  
Chemical Engineering ◽  
High Efficiency ◽  
Load Capacity ◽  
Planetary Gear ◽  
Contact Stresses ◽  
Minimum Size ◽  
Contact Areas ◽  
Technical Requirements ◽  
Maximum Transmission ◽  
Modern Solution

In modern mechanical engineering, transmissions with the use of an involute tooth profile are widespread. However, one of the main disadvantages of these transmissions is that they exposure to wear. In this study, research on the cycloid profile is conducted as an alternative option. Cycloid profiles are one of the profiles applied to the teeth in order to transmit motion. Although cycloid profiles are mainly used in instrumentation, satellites are made of cycloid profile in planetary gears. Cycloid profile teeth are less exposed to wear during operation. Practically, the shape of cycloidal teeth does not allow them to break, so there is no bending deformation in the teeth. In planetary gear transmission, the satellites are usually made of a cycloid profile. Cycloid profile teeth are exposed to less wear. Currently, planetary gear reducers are widely used mainly in the oil industry, drilling equipments, in the lifting mechanisms, gearboxes, on chain conveyors, rotary tables, in robotics, manufacturing, mechanical and chemical engineering fields and so on. The increased load capacity of the cycloid pinion gears is due to the multi-pair contact surface and it has a superior adhesion profile than the involute profile. The loading schemes of cycloidal and evolvent profile teeth shows that the normal force in contact Fn and its dangerous section on the tooth of the cycloidal profile is much less than in the case when the tooth has an involute profile. This is due to the fact that with cycloid profile transmission the number of teeth simultaneously transmitting the load is significantly greater than when implementing the same transmission with involute teeth. Cycloid profile gear reducers can be considered as a modern solution to current requirements such as high efficiency, smooth and quiet work, ability to accept short-term maximum loads, small overall size, minimum technical requirements etc. The simulation of the real load conditions and interference generated during the rotation of the shaft was developed in Solidworks in order to determine the contact stresses and the contact areas resulting from these stresses of the teeth of the gear and satellites of cycloid profile planetary gear reducers. This simulation determines the values of the teeth involved in the contact, the interference of those teeth, the contact areas and the contact stresses generated in these areas, depending on the angle of rotation of the shaft. The profile of the proposed teeth allows to achieve the minimum size with the maximum transmission ratio. Keywords: cycloid profile, cycloid transmission, planetary reducer, interference, simulation, contact area.

scholarly journals Existing problems and measures in safety management of chemical engineering

2018 ◽  
Author(s):  
Yuepeng Liu ◽  
Zhigang Zhang ◽  
Quan Yang ◽  
Qiang Zhang ◽  
Zhen’an Liu
Keyword(s):  
Economic Development ◽  
Chemical Industry ◽  
Chemical Engineering ◽  
Safety Management ◽  
Pollution Prevention ◽  
Construction Process ◽  
Technical Problems ◽  
Engineering Construction ◽  
Technical Requirements ◽  
Management Personnel

For a country, the industry is a very important system, the embodiment of the country's comprehensive national strength, the country's economic development level and the development of science and technology level has direct impact on industry. The development of chemical industry also has great impetus to the national economic development. The technical requirements for chemical engineering are particularly high. Because of the danger of the chemical itself, safety becomes the first thing to notice in the construction process. In order to prevent the occurrence of danger in the actual construction process, the safety of chemical engineering construction is made, and the effective safety management is the most critical step. A reliable safety management is the guarantee for the smooth construction of the construction, so the early safety management becomes the key to the development of the chemical industry. Chemical engineering is an extremely complex and changeable system, and the kinds of problems involved are very many, which requires the construction personnel to pay more attention to ensure the safety. In order to implement the safety management measures in the process of chemical engineering construction, it is necessary for the management personnel to strictly control the whole construction process. In case of any problem, we should deal with it in a timely manner and pay more attention to the details. We should pay attention to fire prevention, pollution prevention and anti-explosion prevention. Technical personnel should pay more attention to technical problems and eliminate safety hazards. The construction company must also strengthen the personal quality of the project management personnel and other issues. It is necessary to examine personal responsibility and safety awareness and avoid unnecessary losses caused by various construction safety issues to the company[1].

The Gear Bearing Drive: A Novel Compact Actuator for Robotic Joints

2013 ◽  
Author(s):  
Elias Brassitos ◽  
Constantinos Mavroidis ◽  
Brian Weinberg
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Low Cost ◽  
Planetary Gear ◽  
Mechanical Efficiency ◽  
Torsional Stiffness ◽  
Maximum Output ◽  
Torque Density ◽  
Robotic Joints ◽  
Advanced Robotics

Advanced robotics requires a new generation of actuators able to exhibit a number of desirable characteristics ranging from high power density and high efficiency, high positioning resolution, high torque capacity and torsional stiffness, lightweight designs and low-cost packages. In this paper, we present the development and the experimental evaluation of a new actuator, aimed at improving the torque density and mechanical efficiency of actuated robotic joints, and enhancing the portability and effectiveness of robotic systems engaged in biomechanical applications such as rehabilitation robots and wearable exoskeletons. The new actuator, called the Gear Bearing Drive (GBD), consists of a two-stage planetary gear arrangement coupled through the planets and driven by an external rotor brushless motor that is inscribed within the input stage sun gear. This planetary configuration enables for incredible high-speed reductions and allows for embedding the motor directly within the gearbox saving significant space on the actuator length. Our initial experimental prototypes have demonstrated impressive performance with the potential to deliver more than 30Nm of continuous torque with 85% mechanical efficiency and 0.0005 degree of backlash, and up to 200 rpm maximum output speed in a highly compact and robust package.

Mixing, Mass Transfer, and Numerical Models

2021 ◽  
pp. 182-239
Author(s):  
Thorvald Abel Engh ◽  
Geoffrey K. Sigworth ◽  
Anne Kvithyld
Keyword(s):  
Mass Transfer ◽  
Water Vapour ◽  
Molten Metal ◽  
Chemical Engineering ◽  
Numerical Models ◽  
Reactor Design ◽  
Hydrogen Gas ◽  
Molten Metals ◽  
Main Metal ◽  
Contact Areas

We want to eliminate dissolved impurities to another phase: slag, gas, solid, or a molten metal that has limited solubility in the main metal. The various phases may be in the form of droplets, bubbles, particles, or walls. The contact areas with metal should be large. The aim in reactor design and operation is to achieve relatively high velocities and small dimensions. Relations for mass transfer are also included since the behaviour of systems with molten metals may be different from that usually treated in chemical engineering. In the field of turbulence the Prandtl eddy length is important for describing removal to walls. Hydrogen in aluminium and the pick-up of hydrogen in aluminium from water vapour is studied in some detail, measured, and modelled. It is taken into account that hydrogen gas is two-atomic. The approach concerning aluminium may be applied to a range of metals.

scholarly journals Implementation of Unbalanced Ternary Logic Gates with the Combination of Spintronic Memristor and CMOS

Electronics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 542 ◽  
Author(s):  
Haifeng Zhang ◽  
Zhaowei Zhang ◽  
Mingyu Gao ◽  
Li Luo ◽  
Shukai Duan ◽  
...  
Keyword(s):  
High Efficiency ◽  
Load Capacity ◽  
Complementary Metal Oxide Semiconductor ◽  
Logic Gates ◽  
Logic Circuit ◽  
Oxide Semiconductor ◽  
Ternary Logic ◽  
Logic Operations ◽  
Almost All ◽  
Logic Functions

A memristor is a nanoscale electronic element that displays a threshold property, non-volatility, and variable conductivity. Its composite circuits are promising for the implementation of intelligence computation, especially for logic operations. In this paper, a flexible logic circuit composed of a spintronic memristor and complementary metal-oxide-semiconductor (CMOS) switches is proposed for the implementation of the basic unbalanced ternary logic gates, including the NAND, NOR, AND, and OR gates. Meanwhile, due to the participation of the memristor and CMOS, the proposed circuit has advantages in terms of non-volatility and load capacity. Furthermore, the input and output of the proposed logic are both constant voltages without signal degradation. All these three merits make the proposed circuit capable of realizing the cascaded logic functions. In order to demonstrate the validity and effectiveness of the entire work, series circuit simulations were carried out. The experimental results indicated that the proposed logic circuit has the potential to realize almost all basic ternary logic gates, and even some more complicated cascaded logic functions with a compact circuit construction, high efficiency, and good robustness.

Technical Requirements for Rapid High-Efficiency Therapies

1986 ◽  
Vol 10 (3) ◽  
pp. 189-194 ◽  
Author(s):  
Prakash Keshaviah ◽  
Doug Luehmann ◽  
Karen Ilstrup ◽  
Allan Collins
Keyword(s):  
High Efficiency ◽  
Technical Requirements

Design and Test of Differential Planetary Gear System for Open Rotor Power Gearbox

2013 ◽  
Author(s):  
Hideyuki Imai ◽  
Tatsuhiko Goi ◽  
Kenichi Kijima ◽  
Tooru Nishida ◽  
Hidenori Arisawa ◽  
...  
Keyword(s):  
Performance Test ◽  
High Efficiency ◽  
High Reliability ◽  
Gear Tooth ◽  
Planetary Gear ◽  
Design Concept ◽  
Gear System ◽  
Open Rotor ◽  
Planetary Gear System ◽  
Validation Tests

The open rotor engine is a next generation aero-engine that satisfies the demand for high fuel efficiency and low CO2 emission. A differential planetary gear system is incorporated in the open rotor engine to connect the turbine output shaft and fan rotors in order to counter-rotate the fan rotors as well as allow the turbine and fan rotors to operate at more efficient speeds. The open rotor gear system is required to have not only 20,000 hp high power transmission, but also an increasingly high efficiency, high reliability and light weight. To achieve these requirements, the following design works were conducted; (1) a low misalignment and lightweight carrier, (2) a flexible structure to absorb the displacement caused by the flight load, (3) an optimum gear tooth modification and (4) reduction of oil churning and windage losses. Also, extensive analyses and simulations such as lube oil flow CFD, FEA and tooth contact analysis were conducted. A full scale prototype gear system was manufactured and validation tests were conducted using a newly constructed test rig to validate the design concept. A slow roll test, rated performance test and efficiency test were conducted. And the design concept was found to be valid. This paper describes details of the prototype design and the results of the validation tests.

scholarly journals Genetic Approach for Multiobjective Optimization of Epicyclical Gear Train

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Kaoutar Daoudi ◽  
El Mosthapha Boudi ◽  
Mohsine Abdellah
Keyword(s):  
Multiobjective Optimization ◽  
High Efficiency ◽  
Bending Strength ◽  
Power Transmission ◽  
Planetary Gear ◽  
Operating Mode ◽  
Optimization Methods ◽  
Gear Train ◽  
Tooth Width ◽  
Power Transmission Systems

The determination of optimal design of the planetary gear train with a lightweight, a short center distance, and a high efficiency is an important issue in the preliminary design of power transmission systems. Conventional and traditional methods have been widely used in optimization. They are deterministic and limited to solve some mechanical problems with several variables and constraints. Therefore, some optimization methods have been developed, such as the nonconventional method, the genetic algorithm (GA). This paper describes a multiobjective optimization for the epicyclical gear train system using the GA. It is aimed to obtain the optimal dimensions for epicyclical gear components like a module, number of teeth, the tooth width, the shaft diameter of the gears, and a performed efficiency under the variation of operating mode of PGT system. The problem is formulated under the satisfaction of assembly and balance constraints, bending strength, contact strength of teeth, and other dimension conditions. The mathematical model and all steps of the GA are presented in detail.

Integrating chemical engineering and crystallographic texturing design strategy for the realization of practically viable lead-free sodium bismuth titanate-based incipient piezoceramics

2020 ◽  
Vol 49 (25) ◽  
pp. 8661-8671 ◽  
Author(s):  
Wangfeng Bai ◽  
Xinyu Zhao ◽  
Yanwei Huang ◽  
Yuqin Ding ◽  
Leijie Wang ◽  
...  
Keyword(s):  
Chemical Engineering ◽  
Bismuth Titanate ◽  
High Efficiency ◽  
Design Strategy ◽  
Lead Free ◽  
Design Strategies ◽  
Sodium Bismuth Titanate

Realization of practically viable lead-free sodium bismuth titanate-based incipient piezoceramics via the integration of chemical engineering and crystallographic texturing design strategies for high-efficiency actuator applications.

Effect of Patellar Tendon Shortening on Tracking of the Patella

2005 ◽  
Vol 33 (10) ◽  
pp. 1565-1574 ◽  
Author(s):  
Neil Upadhyay ◽  
Samuel R. Vollans ◽  
Bahaa B. Seedhom ◽  
Roger W. Soames
Keyword(s):  
Patellar Tendon ◽  
Contact Area ◽  
Knee Flexion ◽  
Patellofemoral Joint ◽  
Contact Stresses ◽  
Contact Areas ◽  
Before And After ◽  
Joint Contact ◽  
Joint Biomechanics ◽  
Patellar Tendon Shortening

Background Although 10% postoperative patellar tendon shortening after bone–patellar tendon–bone autograft reconstruction of the anterior cruciate ligament has been reported, there are no published studies assessing the effect of shortening on patellofemoral joint biomechanics under physiological loading conditions. Purpose To investigate the influence of patellar tendon shortening on patellofemoral joint biomechanics. Study Design Controlled laboratory study. Methods The authors evaluated the patellofemoral contact area, the location of contact, and the patellofemoral joint reaction force and contact stresses in 7 cadaveric knees before and after 10% patellar tendon shortening. Shortening was achieved using a specially designed device. Experimental conditions simulating those occurring during level walking were employed: physiological quadriceps loads and corresponding angles of tibial rotation were applied at 15 °, 30 °, and 60 ° flexion of the knee. Patellofemoral joint contact areas were measured before and after shortening using the silicone oil–carbon black powder suspension squeeze technique. Results After patellar tendon shortening, patellofemoral joint contact areas were displaced proximally on the patellar surface and distally on the femoral surface. Although the contact area increased by 18% at 15 ° of knee flexion (P=. 04), no significant change occurred at 30 ° or 60 ° of knee flexion (P>. 05). Patellofemoral contact stress remained unchanged after patellar tendon shortening (P>. 05) at each flexion angle. Conclusion Our results suggest that a 10% shortening of the patellar tendon does not alter patellar contact stresses during locomotion. It is not clear whether apparent changes in contact location in all positions and contact area at 15 ° would have clinical consequences.

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