日本機械学会論文集C編
Online ISSN : 1884-8354
ISSN-L : 1884-8354
77 巻, 779 号
選択された号の論文の35件中1~35を表示しています
機械力学,計測,自動制御
一般論文
  • 森 博輝, 長嶺 拓夫, 市村 龍美, 佐藤 勇一
    2011 年 77 巻 779 号 p. 2566-2575
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    This paper describes experimental study on self-excited vibration of an elastic rod in swirling flow. We investigate behavior of an elastic rod using two apparatuses, that is, swirling flow is induced by supplying water horizontally along a cylinder wall in an apparatus and by rotating a cylinder in the other. Consequently, two types of vibrations are observed. One is due to vortex shedding. The other is due to the asymmetry of the stiffness matrix of equations of motion.
  • 山田 泰之, 森田 寿郎
    2011 年 77 巻 779 号 p. 2576-2585
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    In this paper, we propose a passive gravity compensation mechanism with two cylinders connected pipeline and a spring element, which named “Hydraulic Gravity Canceller (HGC).” From development and experiments of a single link model equipped with the HGC, it is clarified that this new device has many advantages in comparison with the original ”Mechanical Gravity Canceller (MGC)”and other passive gravity compensation mechanisms. First, this paper describes the new mechanism generates accurate weight compensation torque as same as the MGC without restrictions of spring arrangement and spring constant, because it consists of Pascal's principle-driven mechanism. Next, it is shown that the new mechanism can be installed into heavy manipulators or carry heavy loads while ensuring high rigidity and safety, since there is no risk for amputation of wire. Finally, the new mechanism can be easily added other functions as well as compensation mechanism by fluid pipeline networks. From there, the HGC is new device succeeds to change basic concepts of weight compensation mechanism.
  • 岩本 宏之, 田中 信雄
    2011 年 77 巻 779 号 p. 2586-2600
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    This paper presents global noise reduction in an enclosed sound field using feedback control based on the affinity between cluster control and suppression of acoustical energy density. First, an enclosed sound field is expressed in terms of a state space method. This is followed by the discussion on the validity of the acoustical energy density as a performance index of a control system. It is clarified here that the introduction of acoustical energy density results in the avoidance of uncontrollability. Next, the novel cluster control which is based on the suppression of acoustical energy density is proposed, its stability being analytically verified. Furthermore, from the viewpoint of numerical analyses, the validity of the proposed method is clarified. Finally, the relation between the proposed method and orthogonal contributors in an enclosed sound field is discussed, revealing that the conventional cluster control is the special case of the proposed method.
  • 大田 慎一郎, 西山 修二
    2011 年 77 巻 779 号 p. 2601-2612
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    This paper describes an active control system intended to minimize the vertical vibrations transferred from the seat to the human body in a vehicle. This system controls mechanical properties such as the spring constants and damping coefficients of each part of the vehicle seat by using an optimization algorithm that comprises vibration analysis and an optimization method. To examine the feasibility of the optimization algorithm, we designed a vibration model for the seatoccupant system and calculated the reduction in vibration due to the algorithm by numerical analysis. The mechanical properties of the back and front side of the seat were controlled with reference to the standard condition in the range of 1/1.5-1.5 times, 1/2-2 times, and 1/4-4 times. These results suggest that the respective rates of vibration reduction for the head in the frequency range of 3.6 - 8.5 Hz are 36 % - 52 %, 40 % - 63 %, and 55 % - 76 % for the seat controlled with reference to the standard condition in the range of 1/1.5-1.5 times, 1/2-2 times, and 1/4-4 times, respectively. In summary, the proposed algorithm successfully reduced vibrations from the seat to the human body in a vehicle.
  • 小池 雅和, 中澤 裕司, 千田 有一, 池田 裕一, 安田 悦郎
    2011 年 77 巻 779 号 p. 2613-2626
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    The main focus of the research reported herein is the improvement of the transient vibration suppression performance for large displacements using the active control. A response speed is not sufficient if conventional linear control methods are used to control large displacements because linear input used those methods prevent valves from switching between maximum input and minimum input instantly. So, a solenoid valve is employed, which can switch between maximum input and minimum input instantly. Consequently, the plant includes an on-off action and an input time-delay as the control input. It is known that the stabilization of this kind of system is difficult using conventional linear feedback controls such as the optimal regulator. Herein, FBM (feedback modulator) which compensates on-off action and state feedback control considering time-delay is used as a controller. However, the response may be oscillatory if conventional FBM is directly applied because integral characteristic included in FBM. Hence, in order to avoid such oscillatory inputs, dead-band function is added to the controller in the improvement method 1. If thus configured, response is expected to be stable. Moreover, in order to reduce steady state error, a dead-band compensator is added to the controller in the improvement method 2. As a result, settling time can be shortened to one-fourth of without controlled cases. The effectiveness of the proposed methods is verified by numerical simulations and experiments.
  • 安福 大輔, 藤井 彰, 山本 裕
    2011 年 77 巻 779 号 p. 2627-2641
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    In order to apply failure diagnosis of a rotating machine, normal and abnormal vibrations of a rotating-element bearing were formulated by Herzian contact theory and the results of numerical simulation were applied to decide the existence of a defect. In this paper, firstly three dimensional dynamics of a rotating-element bearing under thrust load were considered and motion equations of bearing elements were developed. And then, in order to consider abnormal vibrations by bearing defects, defects were classified to the three types of impulse train and these impulse trains were added to the motion equations. Moreover, some numerical simulations were conducted by Runge-Kutta method and compared with experimental examples. In the result, it was found that thrust vibrations of a rotating-element bearing has one eigen frequency and this eigen frequency does not change largely by rotating speed and presence of a defect. Using these characteristics, the new method of failure detection was applied to a rotating-element bearing at low speed and the effectiveness of this diagnosis method was confirmed by an example.
  • 木村 康治, 須田 紘司
    2011 年 77 巻 779 号 p. 2642-2649
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    Probability distribution of stationary responses of a nonlinear system subjected to a combined excitation of white noise and random train of impulses is analyzed. White noise and impulses are independent processes. The response distributions are obtained by employing moment equations approach and Gaussian sum approximation, which expresses the probability density function in terms of weighted sum of several Gaussian probability density functions. In the illustrative example, the response distributions of a Duffing oscillator are calculated and compared with simulation results. The effects of impulses upon a tail of these distributions are clarified.
  • 井上 剛志, 船戸 隆由, 高木 賢太郎
    2011 年 77 巻 779 号 p. 2650-2661
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    The magnetic levitation system has not only the strong nonlinearity in the magnetic force but also the delays in electric circuit and magnetic circuit. This paper investigates the modeling of the magnetically levitated body considering both of them. The dynamic coefficients of the electric circuit and magnetic circuit of control system are estimated independently by using the transfer function. The model and estimated parameter values are validated experimentally by comparing the resonance curves of numerical simulation and experiment.
  • 梶原 逸朗, 小原 賢也
    2011 年 77 巻 779 号 p. 2662-2672
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    This paper proposes an innovative vibration testing method for membrane structures based on impulse response excited by laser. Non-contact impulse force is generated by irradiating a high power pulse laser to a structure. The laser excitation makes a precise measurement of the frequency response in wide frequency range possible because an ideal impulse force is applied to a point on the structure. Using a laser Doppler vibrometer to detect a response of the structure, both non-contact laser excitation and measurement are achieved in the vibration testing system. Furthermore, a vibration measurement of the membrane structure in vacuum environment is effectively conducted by using the proposed vibration testing method with a vacuum chamber. The validity of the present vibration testing system is verified by evaluating the measured data of the membrane structure in the vacuum chamber.
  • 瀧山 武
    2011 年 77 巻 779 号 p. 2673-2683
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    The regulation about emission purification and fuel consumption of an automobile becomes increasingly strict for environmental issue. Especially, the performance while transient state is focused on because transient state was increased in the new JC08 emission test-mode. Emission purification of the gasoline engine is attained both using a three way catalyst and controlling air fuel ratio(AFR) by means of an oxygen sensor while steady state. However, while transient state, AFR is deteriorated because of non-linear character such as a fuel wall-wet flow balance, allowance of each engine, aging and ambient of operation. Therefore, highly performed controller is necessary for AFR control at transient state. In this paper, an application of simple adaptive control(SAC) is investigated for AFR regulate control to compensate a disturbance affection at transient state. SAC has two degrees freedom system that was consist of both a feed forward tracker and a feedback stabilizer. Then, SAC control the time response of a plant to agree with that of a reference model. However, there were few report that SAC was applied as a regulator to overcome a disturbance. This paper investigated the control system to apply SAC for AFR regulate control at transient state. Then, the experiment were carried out at different operating condition, and the results showed a good regulating performance as a transient state regulator.
  • 櫻田 巧, 水野 毅, 髙﨑 正也, 石野 裕二
    2011 年 77 巻 779 号 p. 2684-2694
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    The feasibility of parallel magnetic suspension is studied experimentally. Parallel magnetic suspension suspends multiple floators with a single power amplifier. Parallel magnetic suspension systems are classified according to the number of floators (multiplicity) , the output type of amplifier and the connection method of coils. This paper focuses on the current-controlled double suspension system with series connected coils. An experimental system is built by combining two magnetic suspension systems. A simultaneous stable levitation of the two floators was achieved by using PD control with a single power amplifier. Several dynamics characteristics were measured. They agreed with simulation results in tendency.
  • 佐藤 博則, 井関 雄士, 宇津野 秀夫, 松久 寛, 山田 啓介, 澤田 勝利
    2011 年 77 巻 779 号 p. 2695-2710
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    Blood pressure pulse wave is propagated from heart to peripheral blood vessels with changing its waveform according to characteristics of pass way. Dynamic characteristics of total arteries have been investigated by wave equation on multi-branched arterial model. Some diseases, such as an abdominal aortic aneurysm, can be predicted by using the relation between the pulse waveform and arterial stiffness. The aim of this research is to propose a new method to detect such diseases based on the pulse wave propagation model on an arterial tree. In this paper, influences of tissue surrounding an artery, model of peripheral arteries and elasticity of arteries are investigated to elaborate a multi-branched arterial model of human body.
  • 赤木 徹也, 堂田 周治郎, 趙 菲菲, 藤田 圭司
    2011 年 77 巻 779 号 p. 2711-2719
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    Due to the ageing and the decreasing birth rate in Japanese society, an important problem of providing nursing care for the elderly has occurred. Therefore, it is strongly desired to develop a wearable actuator to use in nursing care or rehabilitation. The purpose of this study is to develop a high-power flexible actuator which can be used in supporting a bathing. We proposed and tested a rubber artificial muscle with the inner diameter sensor which consisted of two photo reflectors. This inner diameter sensor can be expected to estimate the axial-direction displacement of the rubber artificial muscle. The position control was carried out using the actuator with the built-in inner diameter sensor and the quasi-servo valve. As a result, the axial-direction displacement of the actuator could be estimated well by the tested inner diameter sensor, and a good position control performance was obtained even when a load mass of 29.4N existed. As an application of the tested actuator, the large-scale bending actuator was also proposed and tested. As a result, its maximum bending angle is about 90 degrees. The bending angle of the actuator could be also estimated well using the tested inner diameter sensor.
  • 長瀬 賢二, 林 剛史
    2011 年 77 巻 779 号 p. 2720-2733
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    This paper considers a new feedback control design methodology for multi-fingered robot hands applicable to multiple contact situations. In our previous work, in the hard contact case, we proposed a control design method applicable to variable contact situations based on the relative motion of the grasp polyhedrons, whose vertexes are defined by the contact points on the fingers and the object. In this paper, we extend our previous results to the soft contact case, where deformation of the fingers and/or the object is included in the consideration. The proposed controller can directly handle the tasks with multiple contact situations such as the catching/releasing task by choosing appropriate desired trajectories without switching control architecture. A numerical example of the catching/releasing task for a moving object is conducted to show effectiveness of the proposed method.
  • 山田 萌, 佐野 滋則, 内山 直樹
    2011 年 77 巻 779 号 p. 2734-2741
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    This paper deals with landing control to achieve stable biped walking on unknown and uneven terrain, and presents a walking control method that consists of a walking motion generator and landing controller. It is important to suppress an impact force and to place a foot on the actual ground for landing on such terrain. Because the conventional foot generally has a rigid body, it is difficult to suppress the impulsive reaction force. To achieve the above two objectives simultaneously, a landing controller for adjusting a foot position by feeding back the reaction force has been proposed in our previous study. This controller provides the robust stability of control system with respect to terrain variance and exact positioning of the foot to actual ground without exceeding reaction force. In this study, this controller is applied to a simple biped robot that has spring embedded feet. The effectiveness of the proposed walking control method on unknown and uneven terrain is demonstrated experimentally.
  • 戸森 央貴, 前田 浩之, 中村 太郎
    2011 年 77 巻 779 号 p. 2742-2755
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    Robots have entered human life, and closer relationships are being formed between humans and robots. It is desirable that these robots be flexible and lightweight. For this reason, we studied and developed an artificial muscle actuator using straight-fiber-type artificial muscles derived from the McKibben-type muscles, which have excellent contraction rate and force characteristics. However, these muscles have highly nonlinear characteristics, as well as high compliance and a strong hysteresis characteristic. Hence, it is difficult to control the artificial muscle manipulator. In this study, we developed nonlinear dynamics model of the artificial muscle, investigate nonlinear dynamics characteristics of the muscle. In addition, considering nonlinear dynamic characteristics of the artificial muscle, we implore control speck of 6-DOF artificial muscle manipulator.
技術論文
  • 西 将志, 神田 亮, 渡辺 亨, 渡辺 昌宏, 田中 秀和
    2011 年 77 巻 779 号 p. 2756-2770
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    In the present papers, we propose a new approach for simulating the aerodynamic vibration of structures in a wind tunnel and discuss its application. The concept of the proposed approach is a step-by-step computer simulation using the measured external wind force acting on a structural model in the air flow of a wind tunnel. This approach is referred as to the Modified Hybrid Aerodynamic vibration Technique (MHAT). At first, the concept and advantages are explained. In the next place, the development of a simulation system based on this approach and the accuracy of this system are described. In additional, the outline of conducted simulation by means of this approach is indicated. In order to demonstrate the application of MHAT, two simulations are performed. First, the aerodynamic vibration of a square prism on a single-degree-of-freedom elastic model is simulated in three-dimensional flow. Then, the air pressure field acting on the model is analyzed by means of the Proper Orthogonal Decomposition. Second, the aerodynamic vibration of a square prism is simulated using a multi-degree-of freedom elasto-plastic model. These simulations prove the broad applicability of MHAT. In additional, it is discussed whether MHAT can simulate the vibration of structures in liquid sodium even under in air flow or not.
  • 湯村 敬, 宇都宮 健児, 福井 大樹, 岡本 健一, 大須賀 公一
    2011 年 77 巻 779 号 p. 2771-2781
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    A ride comfort of elevator system is one of the important factors to enhance the product value. Elevator lateral vibration is the main problem that affects ride comfort. In order to improve ride comfort, it is important to achieve an estimation and optimum design of the cage suspension system. In this paper, a time domain simulator for elevator lateral vibration is developed. We made detailed simulation models of roller guide system and slide guide system in order to evaluate ride comfort on the design stage. Comparing with the simulation results and experiment results, guide system behaviors under various conditions become clear. The simulation models are improved with these behaviors. Fine matching of simulation and experiment are confirmed with the improved models.
  • 山口 智也, 油田 信一
    2011 年 77 巻 779 号 p. 2782-2794
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    The purpose of this research is the development of a practical long distance navigation system of mobile robots in outdoor environment. We defined the research target as ”An autonomous mobile robot runs on the sidewalk of 3.5km loop-street at Univ. of Tsukuba” and we have developed a experimental system for autonomous travelling in the defined environment. In the developed system, the route was divided into sidewalk sections and intersection sections, and the suitable methods were installed for both type of sections. In sidewalk section, the robot travels based on the road edge detection by laser range sensor, and in the intersections, the robot runs based on the teaching-playback scheme using the scan data by laser range sensor. In this paper, we explain the defined problem and the basic structure of the navigation system, We also report the experimental results in the defined route and discuss on this results with findings got from this research.
再録論文
  • 舟木 治郎, 渕 拓也, 大西 祐介, 長坂 繁弥, 多久島 朗, 佐藤 誠司, 平田 勝哉
    2011 年 77 巻 779 号 p. 2795-2804
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    The present study is a fundamental approach to reveal the minute fluctuating pressures on three-dimensional blade surfaces of a basic propeller fan. Because, among the concerning physical quantities, the unsteady pressures on the rotating blades give us useful information for the fan flow and its sound-noise level. The authors correct the centrifugal-force effect, the gravitational-force effect and the other leading-error effects for accurate measurements of the minute pressures using a measuring technology developed by the authors (Hirata et al., 2009). As a result, we show the Reynolds-number effects and the spatial distributions on the blade of both time-mean pressure and pressure-fluctuation intensity.
機械要素,潤滑,設計,生産加工,生産システムなど
研究展望
一般論文
  • 湯本 淳史, 上田 学, 進士 忠彦
    2011 年 77 巻 779 号 p. 2822-2831
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    We applied an axial flux motor to the one-degree-of-freedom controlled magnetic bearing (MB) which we had proposed and designed for centrifugal blood pumps. The axial flux motor, which has little effect on the stiffness of the magnetic bearing, consists of Halbach permanent magnet arrays in the rotor and coreless motor coils in the stators. An experimental rotor, which was 52mm in diameter 18.5mm in height and 0.14kg in weight, could levitate stably. The rotor could rotate at a rotational speed of up to 3,000rpm when the bearing and motor gaps were filled with the glycerin fluid whose density and viscosity were as same as human blood at room temperature.
  • 大塚 茂, 矢壁 正樹, 権田 岳, 徳島 秀和
    2011 年 77 巻 779 号 p. 2832-2841
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    This study proposes the combinations of some hydrodynamic shapes formed on the end or the annular surface of oil impregnated sintered porous bearing as a DC spindle motor's bearing system. Hydro Wave Bearing or Pump In as a thrust hydrodynamic shape, and Herring Bone (I&II), Three Lobed Type or Sleeve as a radial hydrodynamic shape were proposed, and the total of eight kinds of combinations were produced as thrust-radial coupled bearing. It examines to optimize the hydrodynamic shape combination experimentally as thrust-radial coupled bearing by measuring the lubrication characteristics. This research report is especially referred to the experimental examination for Settling Time, Lissajous Curve diagram or Shaft Whirling by measuring the Time History Waveform of shaft such as the lubrication characteristics under unsteady shaft starting condition.
  • 酒井 忍, 山崎 光悦, 鈴木 武之, 中野 正貴, 浅田 浩治
    2011 年 77 巻 779 号 p. 2842-2854
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    Crankshaft miller is a machine tool used to mill crankshafts for engines. The miller causes a great amount of heat during the cutting process, which combines heavy and intermittent cutting. In this paper, the approximation equation of thermal displacement which applied a method to estimate thermal deformation on the basis of a few machine temperatures and the finite element analysis is proposed. The thermal characteristics and the mechanisms of heat transformation in the crankshaft miller are made clear by numerical simulations using the finite element models of the miller and the experiments. The simulations tried a steady and transient state analyses of heat transformation to consider the heat transfer coefficient in the cutting process. From the results of the analyses, the temperature distribution and thermal deformation on each part of the miller were found. The results of analyses are compared with the experimental values using the actual miller. The point of efficient measuring temperature and the calorific values in order to revise each coefficient value in the approximation equation were examined. Additionally, the effectiveness of proposed approximation equation was shown.
  • 田辺 郁男, 近藤 大透, 井上 大和, 井山 徹郎
    2011 年 77 巻 779 号 p. 2855-2862
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    Recently, several machines with linear motor were developed for high productivity. Feed behaviour of these machines is required high speed, high acceleration and stable behaviour for feed. Other hand, mirror surface was required for adding high quality on the most products. We thought that this linear motor drive suit well for manufacturing on the mirror surface. Therefore, In this paper, high speed and fine polishing using linear motor was investigated for mirror surface. Polishing device was firstly developed for the experiment. The device consists of the NC milling machine, the linear motor driver and the polishing head. The linear motor driver with the polishing head was setted in the spindle of the NC milling machine. A shaver (=shaving device) was substituted for linear motor drive. Epoxy resin was used for the polishing head. Process for making the head, property of polishing and the optimum polishing condition are investigated in several experiments. This system was evaluated for high speed polishing on the flat surface and fine polishing using a minute part. It is concluded from the results that (1) Mirror surface was machined by this polishing system, (2) The polishing time using this polishing system is one tenth of that of the conventional polishing, (3) Minute part which size is about a few mm was machined for mirror surface by this polishing system.
  • 梅崎 洋二, 舟木 義行, 黒河 周平, 大西 修, 土肥 俊郎
    2011 年 77 巻 779 号 p. 2863-2874
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    The wear resistance of coating films on hob cutting teeth is investigated by intermittent cutting tests with a flytool. The coating films on hob teeth are titanium family ceramics such as TiN, TiCN, TiSiN and TiAlN and aluminum chromium family ceramics such as AlCrN and AlCrSiN. The wear resistance of coating films is shown with regard to film thickness, film materials, ingredient ratio in a film component and the effect of the oxidization on coating films. The oxidization is clarified through the influence on the crater wear propagation through wear cutting tests in atmosphere such as nitrogen gas or oxygen gas. The oxidization of TiAlN coating films produces oxidation on the tool rake face, and this oxidation relates to the amount of crater wear. The increase of aluminum concentration in the TiAlN film improves the crater wear resistance in air, while it has a reverse effect in nitrogen gases, though. The AlCrSiN film has effective resistance against the wear such as abrasive wear and/or oxidization wear. The oxidation film formed on the AlCrSiN film is very firm and this suppresses the oxidations wear on the rake face and works against the abrasive wear advantageously.
  • 山中 将, 土屋 慎治, 成田 幸仁, 井上 克己
    2011 年 77 巻 779 号 p. 2875-2883
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    A novel CVT mechanism (a shaft drive CVT) was developed by the authors. In the mechanism, the input and output shafts with conical disks are parallel and an idler shaft with conical rollers at both ends is placed perpendicular to the input/output shafts. This idler shaft transmits torque from the input shaft to the output shaft and its linear motion causes the speed to vary by changing the contact point between the input/output disks and the idler roller. The backup disks are connected to the input/output shafts and do not contribute to power transmission. In this paper, we propose a mechanism to transmit torque between the backup disks and input/output shafts to enlarge the amount of transmitted torque. A gear train was added behind the backup disk for new torque path. Its effect is examined and confirmed by the experiment using the prototype CVT. The efficiency of 3 percentage points was improved and the torque capacity became twice by the contribution of backup disk.
  • 平山 朋子, 鳥居 誉司, 小西 庸平, 前田 成志, 松岡 敬, 井上 和子, 日野 正裕, 山崎 大, 武田 全康
    2011 年 77 巻 779 号 p. 2884-2893
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    Thicknesses and densities of additive adsorbed layers on metal surfaces under lubrication were directly measured by neutron reflectometry. Two kinds of metal surfaces, iron and copper, on ultra-flat silicon blocks were prepared by physical vacuum deposition. After that, each target surface was analyzed by neutron reflectometer SUIREN in air, in base oil (poli-alpha-olefin) and in base oil with deuterated acids as additives. Fitting operation based on Parratt's theory showed that the thicknesses of additive adsorbed layer on the iron and copper surfaces were quite thin, only 1.5-2.0 nm. The friction coefficients of the metal surfaces, measured by a ball-on-disk friction tester, decreased considerably when the additive was added to the base oil. We concluded that the additive adsorbed layers on the metal surfaces considerably affected friction properties despite being only several nanometers thick.
  • 野口 昭治, 松尾 和昭, 吉川 悟史, 野木 高
    2011 年 77 巻 779 号 p. 2894-2904
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    In general, rolling bearings are used in continuous one-way rotation. Additionally, they are used in oscillating site such as a swing arm in a hard disk drive. In the swinging movement for several tens of degree in angle, the rolling elements contact the limited range of race surface. Therefore, fretting is easy to occur at the both ends of the contacting range. Then, lubricant agent and addition agent are applied to prevent the occurrence of fretting. However, in the experiment of swinging movement for small ball bearing, the revolution of the rolling elements could be seen and the fretting did not occur in the small ball bearing. Thus, in this research, the authors considered that fretting could be prevented by changing the contacting range caused by the revolution of rolling elements. Then, experimental analysis on observation of revolution of rolling elements and acceleration technique of the revolution was conducted. Accordingly, the following points were clarified. (1) Giving speed variation between to-motion and from-motion in the swinging movement will bring the revolution into existence. (2) The direction of revolution depends on the frictional condition between the rolling elements and the track surface.
  • 竹内 彰敏, 北邑 有希雄
    2011 年 77 巻 779 号 p. 2905-2915
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    In this study, a flat thrust bearing is developed by active exploiting the slip flow generated on a water-repellent surface. In order to produce a load, this bearing has a structure that generates a pressure flow by using the discontinuity of shear flow rate between a water-repellent surface and an untreated or a hydrophilic surface. This structure results in the completely flat bearing that has no geometrical variations in its surface. Friction tests were carried out with respect to the water-repellent thrust bearing that consists of three water-repellent parts and untreated or hydrophilic parts. The results verified that this partial water-repellent thrust bearing functioned well with a low and stable friction coefficient (less than 0.002). And lubrication surfaces had no damages at all because both surfaces are separated with fluid film which enables to avoid the solid contact. The friction coefficient became lower for the bearing having large difference of contact angle (thus, shear flow rate) between both parts. Furthermore, a friction coefficient for the bearing of which water-repellent part and hydrophilic part had same area was the lowest, and friction coefficient became larger than its value in case of not only wide water-repellent part but also narrow one. These results suggest a possibility that this thrust bearing operates by the same mechanism as a conventional bearing under fluid lubrication.
  • 中島 悠也, 梅原 徳次, 野老山 貴行, 赤上 陽一
    2011 年 77 巻 779 号 p. 2916-2921
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    Radio knife is a common tool in surgery. However it has a severe issue that it strongly adheres to the human body frequently through the coagulation of blood and/or human tissues. In order to overcome this issue, we developed the new tip for the radio knife that have many micro grooves on the tip and the grooves were filled with several kinds of materials. It was conducted that the new tip was evaluated in the adhesion test between the tips and porcine liver. As a result, adhesion force for the patterned tip which was filled with several kinds of material decreased to 8% comparing to normal tip. Consecutive cutting time increased to 5 times comparing to the normal tip.
技術論文
  • 菅澤 昌之, 大場 光太郎
    2011 年 77 巻 779 号 p. 2922-2931
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    In the digital video camera and the digital still camera, it is necessary to cover to protect the lens, because lens is prevented being damaged by grit and dust storm etc. of outside environment. There are a lot of manufacturers that has a lot of defective products of the lens cover. Many of lens cover products have caused the defect that the cover doesn't open even if it turns on power. A reason of many causes is as follow. When the grit the dust storm enters to the internal mechanism of the lens cover, the gear doesn't rotate. The lens cover is set to defend the lens from the scratch and protect from dirt and pollution, and to reduce the trouble of the product, but it yields opposite effects. "To defend the lens from the scratch, we want to close the cover firmly at any condition." Is above-mentioned the demand definition of the lens cover really correct really? We pursue a blind spot of the idea and target rationality. We redefine the demand of the lens cover.
  • 竹内 純一, 山崎 良, 谷 和美, 高橋 康夫
    2011 年 77 巻 779 号 p. 2932-2939
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    In state-of-the art semiconductor manufacturing equipments such as Etch, CVD and PVD chambers, it is very important to consistently fix silicon wafers on the susceptor. The electro-static chuck is used for the susceptor. The main functions are to improve the accuracy of positioning and temperature controlling. In this study, Al2O3 coatings were developed using Atmospheric Plasma Spray (APS) and Vacuum Plasma Spray (VPS) and their basic electrical and mechanical characteristics were investigated. In the investigation, several characteristics of Al2O3 coatings by using both plasma spraying processes were resembled. It was found that the dielectric constant value of the APS Al2O3 coating is higher than that of the VPS coating below 373K. APS'ed coatings also had the advantage of thermal conductivity in the range of from 373K to 500K over the VPS'ed coating. The results showed that APS'ed coatings have advantages over VPS'ed coatings for electro-static chucks. The results also suggest the feasibility for using the APS'ed Al2O3 coatings as a dielectric layer on electro-static chuck
  • 久保 登, 森 みどり
    2011 年 77 巻 779 号 p. 2940-2952
    発行日: 2011年
    公開日: 2011/07/25
    ジャーナル フリー
    Drive video recorders (DRs) have been installed on a plenty number of the taxicabs in large cities in Japan. This paper discusses how to carry out a detailed traffic accidents analysis using drive video recorder data obtained in Tokyo. The sequential motions of the cars concerned before and after the crash are illustrated throughout a process in the case studies of two traffic accidents. The causes of the accidents are discussed as well as measures to prevent the accidents and the DR data requirements for effective analysis based on the motion picture and the log data recorded by the commercial DRs. This newly-developed approach makes those possible to carry out the reproduction of the accident process, the estimation of the causes and the background factors, and the consideration of the preventive safety measures. It is more effective to make such analysis by using not only the DR data but also the Internet resources such as a map, an aerial photograph and other information. The requirements of DR hardware and DR data for the proper analysis of the accidents were also examined.
feedback
Top