Recent Patents on Mechanical Engineering - Volume 8, Issue 2, 2015

Using viscosity of fluid between friction pair to transmit power is called the Hydro-viscous Drive (HVD), which has obvious energy-saving effects on soft start and speed regulation. In this review, we introduce the basic principle of HVD and HVD production development, and emphasize the potential of ever increasing power of HVD in future industrial applications. The current status of research in HVD is described which includes the improvements in the understanding of transmission mechanism of the oil film between the friction pair and in the development of intelligent control systems for HVD based devices. In particular, four aspects of HVD need to be further researched, which include the development of higher power HVD devices, new friction materials, multi-friction pair coupling issues and new intelligent control systems. The goal of this review is to attract the attention of researchers to these fertile areas of investigations related to HVD; and to provide an overview about the oil film transmission between friction pair by addressing recent patents and scholarly articles on the subject of design, control and application of such systems.

With the increasing application of mechanical engineering in medical areas, bone drilling has become one essential part of orthopedic surgery. Recently, there are more and more researches and developments on bone drilling for fixing implants or widening operative field and related equipments. However, the uncontrollable axial force and over high drilling temperature during bone drilling not only influence drilling quality and loose the prosthesis implants, but also are easy to cause fracture nonunion and various operative complications, thus prolonging the recovery time. All existing drilling equipments employ manual feed and depend to a greater extent on the experiences of doctors. Doctors could judge whether bone has been drilled through precise judgment. Excessive feeding because of lack of clinical experiences or misjudgment during operation will cause secondary injuries to patients. Therefore, the author designed a surgical bone drill with controllable axial force. It uses abrasive particle drill, brazed PCBN superhard material drill, step drill and brazed twist drill. It could judge whether the bone has been cut through according to voltage signal collected by the intelligent integrated control system and thereby stop feeding automatically. Moreover, a theoretical analysis and experimental research on influencing factors of drilling temperature have been conducted to provide references for clinical practice. This paper analyzed advances and patents about medical surgical operation bone drilling equipment in recent years, including cranial drills, bone drills with drillings cleaner, drilling depth adjustable bone drills, automatic stop bone drills and other bone drills.

In the era of miniature, multi-axle steering has been evolved as an expected developing trend for heavy-duty vehicle. The high-performance multi-axle steering system can significantly strengthen the maneuvering flexibility and handling stability of multi-axle vehicle, which is one of the key technologies for measuring the development level of modern large-scale and heavy-duty vehicles. A large number of patents and articles have recently been devoted to the development of multi-axle steering techniques that can significantly improve both maneuvering flexibility and handling stability. Firstly, the optimization, improvement and novel design of steering apparatuses are discussed. Secondly, the new steering systems about the control valves, the redundancy system and the centering and locking of rear steered wheels in electro-hydraulic steering control system are analyzed. Thirdly, the latest design of control methods of multi-axle steering is reviewed. The future research directions are also discussed in the paper. In a word, the paper provides a review of multi-axle steering vehicle, which is extracted from literature and is needed for promising development in multi-axle steering technologies.

The microchannel heat sink is proposed with the advantages of small volume, light weight, low noise, easy integration and high heat transfer coefficient, which can meet the cooling demand for the power density greater than 100 . The latest research status of micro-channel heat sinks is summarized in this paper, and the typical design structures are analyzed. In this paper, various patents have been discussed, and an overview of its application fields and the main problems are showed. The prospect and development trends are also described in this paper.

Blade flutter of wind turbine causes serious problems so as to hinder wind capture and utilization to a large extent. To cope with the problem and promote the flutter self-suppressing capability, a damping blade with high damping characteristic is proposed. The damping blade is mainly comprised of the girder and the panel which are respectively treated through the method of free damping layer and co-curing constrained damping layer. At the same time, its parameter identification including thickness of damping layer and structural loss factor is derived theoretically. For validation and evaluation of flutter suppression effect, dynamic model considering the aerodynamic and structural factors is established, and numerical simulation is carried out. The results indicate that the proposed damping blade displays outstanding flutter self-suppressing capability in contrast to the conventional blade. Recent patents on the blade flutter suppressing for wind turbine are also addressed.

Automatic equipment greatly improves the industrial manufacturing efficiency, as its brain, the motion control system exerts significant influence over the operating performance. In recent decades, there has been an ever increasing concern for developing motion control systems with more applicable characteristics, especially those that can easily fit into various occasions. It is with such motivation that distinct features, schemes and developments of existing motion control systems are here identified and evaluated, including some recent patents and academic publications in the related area. The purpose of this study is to provide an overview of the typical motion control systems in terms of architecture, and summarize the potential directions of the future developments.

Recently developed heat transfer augmentation techniques, such as surface texturing (US20120274029) and built-in heat pipe (US20140327211), show potential in significantly lowering the rubbing face temperature of the parallel sliding tribocomponents, such as mechanical seals and bearings. In addition, recent experimental results have revealed that lowering the face temperature tends to lower the rubbing face friction coefficient and wear rate. As a result, implementation of heat transfer augmentation techniques, especially the built-in heat pipe, can dramatically improve lubrication between the parallel sliding components. While comparing a lubrication system with a conventional disk (CoD), the utilization of a built-in heat pipe disk (HPD) results in lower face temperature, more uniform face temperature distribution, and less thermal deformation. Although, the prototype HPD tested in this study has a thinner wall thickness compared to that of the CoD, numerical simulations of loading on the rubbing face reveal that the mechanical deformation has little impact on the surface lubrication.

In order to analyze the effect of rotation speed of a friction pair on transmission characteristics of a rotating oil film, a 3D computational model of an oil film between a friction pair is built; pressure, temperature, velocity, and torque transferred by the rotating oil film are investigated at rotation speeds of 1000r/min, 3000r/min, and 4000r/m using the computational fluid dynamics (CFD) software ANSYS Fluent. It is found that the highest pressure in the oil film decreases with increase in rotation speed and its value decreases gradually along the radial direction. However, the distributions of velocity and temperature are opposite to that of the pressure; the highest value of these quantities appears at the outer radius. The torque, which is proportional to the rotation speed, is also calculated theoretically and is compared with the CFD simulation results. The purpose of this study is to provide an overview about the effect of rotation speed of a friction pair on transmission characteristics of oil film by addressing recent patents and scholarly articles on the subject of design, control and application of such systems.

Electric Discharge Machining (EDM) is a prominent machining technique used mainly to machine difficult to cut metals and alloys. The major challenges faced in EDM are high Tool Wear Rate (TWR), overcut and poor surface quality. To overcome these challenges, this research aims to improve the TWR and overcut. The experiments were conducted on the EDM using Copper (Cu) electrode, Cryogenically Treated (CT) Cu electrode, Brass electrode and CT Brass electrode by changing the voltage, pulse on-time and discharge current values. Based on the conducted experiments CT Cu electrode, there is a significant improvement in TWR and overcut by 24 times and 2.5 times respectively compared to other electrodes. Further, the incidence of micro-cracks and void occurring in workpiece due to heating and cooling on the cutting surface is analysed through SEM analysis which substantiates that the CT tool produces the least number of cracks compared to other electrodes. Patents related to electrodes, issued since 1994 are selected for the survey. On comparing these patents, it is evident that the most of the patents aim to minimize the tool wear through various mechanisms.

In order to research the identification methods for shearer cutting status, some relevant patents and scientific references are studied and analyzed. A new method based on the integration of particle swarm optimization (PSO) and support vector data description (SVDD) is proposed to identify the shearer cutting status. The PSO is provided to solve the constraint optimization problem of SVDD. Some key technologies are proposed to balance the search ability and enhance the population diversity of PSO, and the flowchart of proposed method is designed. Furthermore, some simulation examples are carried out and the compared results indicate that the proposed method is feasible and efficient. Finally, an industrial application example of coal mining face is demonstrated to specify the effect of proposed system.