Transactions of the Japan Society of Mechanical Engineers Series C
Online ISSN : 1884-8354
Print ISSN : 0387-5024
Volume 73, Issue 732
Displaying 1-31 of 31 articles from this issue
  • 4th Report, Measuring Method on the μ Value Between Rails and Wheels
    Hironori HASHI, Yu SATO, Satoshi USHIWAKA, Kazuhiko NAGASE
    2007 Volume 73 Issue 732 Pages 2175-2181
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    Under the critical condition of a wheel climb derailment, the friction coefficient on the contact point position between a wheel flange and a rail is said to seriously affect on the occurrence of the derailment. However, the site of the contact point position is so variously and so complicatedly transferred on the rail side according to the rotation of the wheel set that it is said to be impossible to quantitatively and exactly evaluate the coefficient. At the critical derailment condition, the relation between the friction coefficient and the wheel climb derailment coefficient is shown by the Nadal's equation, and the critical conditions can identify though the investigation into the difference between the theoretically calculated wheel climb-up value and the practically measured one. Employing a model truck and a model track, experiments were done to investigate the friction coefficient using the above mentioned method. As the result of experiments, it was found that the friction coefficient on a dry rail was nearly equivalent to the adhesion coefficient.
    Download PDF (1138K)
  • Yuichi SATO, Takuo NAGAMINE, Koji OSHIMA
    2007 Volume 73 Issue 732 Pages 2182-2188
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    A soot blower is used to blow off soot on tubes in a tubular heat exchanger, or a gas heater. The soot blower has a long flexible tube, that is, a lance tube, about 10 m long and 76 mm in diameter, which is put slowly into/out of a gas heater. Steam flows through the lance tube and is discharged at the free end to blow off soot. The lance tube, rotating slowly about its axis at about 12 rpm, is supported at an intermediate position by a support bearing, that is, a lance bearing. Vibrations and noises occurred in operation while a lance tube is put into a gas heater. They are considered self-excited vibrations due to friction between the lance tube and the lance bearing. Experimental study is done to clarify the mechanism of the vibration. Accordingly, backward whirling motion of a shaft is observed. Analytical study is also done which clarify the mechanism and characteristics of friction induced vibrations.
    Download PDF (1056K)
  • Nobuhiro WAKABAYASHI, Kenichiro OHMATA, Hirokazu SAITO
    2007 Volume 73 Issue 732 Pages 2189-2196
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    In this paper, a friction damper that has resisting force characteristics of hardening type and returning to the original position was proposed. The friction damper is composed of stacked two sets of V-shaped links, coil springs, brake shoes, a load column, outside and inside frames. The resisting force characteristics of the damper, and the frequency and seismic responses of a single-degree-of-freedom system supported with the damper were analyzed. The trial damper was made, and the resisting force characteristics and the effects of vibration suppression of the damper were substantiated experimentally and numerically.
    Download PDF (933K)
  • Toshiharu ARAKAWA, Yuichi KODAIRA, Kenichiro OHMATA
    2007 Volume 73 Issue 732 Pages 2197-2203
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    A new type of two-dimensional dynamic vibration absorber which has a simple construction and low height has developed. The dynamic absorber is composed of a mass, semicircular arc springs, rare-earth magnets and free bears, and is able to move in every horizontal direction. The dynamic absorber is suitable for suppressing the vibration of small structures, such as three-story wooden houses, due to an earthquake, a wind or a ground motion. The modal mass and stiffness were calculated, and the optimum condition of the dynamic absorber was calculated using the fixed points theory and the area under the acceleration curve. The trial dynamic absorber was made and its resisting force characteristics were discussed experimentally and theoretically. The trial dynamic absorber was attached to the third story of a 3-story building model, and the frequency and seismic responses of the building model were measured using a permanent magnet type vibration table. The experimental results were compared with the calculated results, and the effects of vibration suppression of the dynamic absorber and the propriety of the calculations were confirmed.
    Download PDF (1056K)
  • Nobuyuki KOBAYASHI, Kazuhiro HAKAMADA
    2007 Volume 73 Issue 732 Pages 2204-2210
    Published: August 25, 2007
    Released on J-STAGE: August 16, 2011
    JOURNAL FREE ACCESS
    A new type seismic isolator system for the tower crane is presented. The isolator system is composed of two components. One is an isolator for the mast of the crane using a cubic four bar links, springs, dampers and stoppers. The other is the elastic stay, which connects a stay supported type tower crane to the structure under construction. The natural period and the damping coefficient of the tower crane can be turned by adjusting spring constant, damping coefficient of dampers and the stiffness of stays. Numerical simulations for a self-stand tower crane and a stay supported type tower crane with the presented seismic isolator system and these without seismic isolator are carried out. The shaking table exciting test for a self-stand tower crane model with the presented seismic isolator is also carried out. As the results, the simulation results and the experimental results demonstrate that the presented isolator system is effective to decrease seismic inertia force.
    Download PDF (1123K)
  • Masanori SHINTANI, Naoya TAGUCHI, Yuichi HATTORI
    2007 Volume 73 Issue 732 Pages 2211-2216
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    This paper deals with development of new isolation device by using friction force. This isolation device carries out reduction of horizontal relative displacement by using friction force. The isolation device uses a slope plate. The Friction force acts on the slope plate. The restoring-force is given to the isolation device from the compression spring attached to the base. In the equation of motion of analytical model, the friction force changes in proportion to displacement. The restoring-force is also proportional to displacement. The restoring-force always works in the direction of a center. Therefore, the friction force and restoring-force are proportional to displacement. Simulation analysis is calculated on various conditions using the analysis model. Condition reducing both response acceleration and displacement effectively is examined. The reductions of the response acceleration and the relative displacement are shown by the simulation results. The isolation device for the experiment is designed using the analysis model.
    Download PDF (692K)
  • 1st Report, Derivation of Canonical Equations and Linear Analysis
    Kensuke HARA, Hiroki TAKAHARA
    2007 Volume 73 Issue 732 Pages 2217-2224
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    This paper deals with the internal waves between two bodies of immiscible fluid. In theoretical analysis, we give a formulation for the equations of motion of a system of two incompressible irrotational fluids with a dynamic free surface and interface by a variational formulation. In addition, we derive a Hamiltonian formulation of this problem. This derivation is posed from Hamilton's principle in that the canonical conjugate variables are deduced from the Lagrangian under a Legendre transform. Moreover, we have focused in particular on linearized problems and investigated the character of vibration modes and an amplitude-frequency response of a three-dimensional fluid. On the other hand, the vibration modes and the amplitude-frequency response are obtained experimentally by using a model tank. The theoretical results are shown to be in good agreement with the experimental results.
    Download PDF (1109K)
  • Keiichi HAYASHI, Kiwamu ASHIDA, Hiroshi YABUNO, Masaharu KURODA
    2007 Volume 73 Issue 732 Pages 2225-2231
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    Usage of self-excitation as an excitation method for cantilever-probe in atomic force microscopy (AFM) has been proposed in order to improve the low quality factor Q in liquid environments. For realization of non-contact mode AFM, it is necessary to reduce the amplitude of the self-excited cantilever-probe. In this study, the self-excited oscillation of the cantilever-probe is generated by the angular velocity feedback. In addition, the small steady state amplitude is achieved by nonlinear feedback proportional to the squared deflection angle and the angular velocity. Regarding the micro cantilever-probe as a micro cantilever beam, we show the equation of motion in which the geometrical nonlinear effect is taken into account. Averaged equation is derived by applying the method of multiple scales and the bifurcation diagram is theoretically described. Then, it is clarified that the amplitude of the cantilever-probe can be reduced by increasing the nonlinear feedback gain. By using our own making AFM, we demonstrate the nonlinear dynamics of a “van der Pol” type self-excited cantilever. Steady state amplitude of self-excited oscillation is reduced to 8 nm.
    Download PDF (1204K)
  • Mitsuaki ISHITOBI, Dai KAWASHIMA, Masatoshi NISHI, Makoto KUMON
    2007 Volume 73 Issue 732 Pages 2232-2237
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    This paper considers swinging up of a cart-pendulum system under the presence of modeling error. We propose a control method that swings the pendulum by bringing the behavior of the pendulum to the homoclinic orbit. It is achieved by introducing a new Lyapunov function candidate. However, the cart may move too widely during the swinging of the pendulum. Hence, constraining the cart within the cart track length is also considered to solve the problem. Experimental results show the effectiveness of the proposed control method.
    Download PDF (628K)
  • Yasuhisa TASAKA, Tadashi EGAMI
    2007 Volume 73 Issue 732 Pages 2238-2245
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    In this paper, we present a new path control method with search and the application of the method. A desired point that is at a minimum distance from the present position is searched and the distance is set along the standard axis of the coordinate transformations. A mechanical system in an orthogonal coordinate system is transformed into a mechanical system in a rotational and moving coordinate system. The transformed system can be decoupled and decomposed into a path error component and a error component of moving direction. The path error component is approximately equal to the path error that can converge to zero by the control system of the path error component. The error componet of moving direction is evaluated by means of the total moving distance and the present position is converge to a desired position by the control system of the error component of moving direction. Subsequently, essential path control for arbitrary curve paths can be realized by using the proposed method. The proposed control method is applied to multi-axis linear motor tables, and its effectiveness is confirmed experimentally.
    Download PDF (1227K)
  • Itsuro KAJIWARA, Hirotoshi KATO, Masahiko KONDO, Yusuke SATO
    2007 Volume 73 Issue 732 Pages 2246-2254
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    This paper proposes an approach on broadband robust controller design of multi-frequency-band parallel control system in order to achieve a significant vibration reduction in broadband frequency range. Mechanical systems usually have vibration and noise problems in various frequency ranges. A complex high-order modeling has to be conducted to control the vibration and noise in broadband frequency range. In this case, the modeling error is generally increased, resulting in a degradation of control performance. This study designs the multiple subcontrollers based on the multiple sub-models derived in the corresponding frequency ranges. The order of each sub-model becomes small and so the modeling accuracy is improved. The total controller is constructed as the parallel circuit with each sub-controller designed in each frequency range. Each sub-controller is designed to satisfy the closed-loop stability against the interference to other sub-controllers in thisstudy. It is verified that the calculation efficiency and control performance can be enhanced by the proposed control strategy.
    Download PDF (1327K)
  • 1st Report, Evaluation Model and Characteristics of Pressure Pulsations Under Resonant Conditions
    Itsuro HAYASHI, Shigehiko KANEKO
    2007 Volume 73 Issue 732 Pages 2255-2262
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    Pressure pulsations in piping systems excited by a centrifugal compressor or fan at blade passing frequency were investigated by experiment and numerical simulation. A one-dimensional pressure excitation source model for a compressor was proposed based on the equation of motion, to establish the practical evaluation method for pressure pulsations in piping systems. As a result of experiment, the maximum pressure amplitude in a piping system increased as the location of a compressor was close to the node of the pressure distribution of the resonant mode. This relation between the maximum pressure amplitude in piping systems and the location of an excitation source under resonant conditions can be evaluated by introducing the equivalent resistance of a compressor and that of piping systems. The role of the system resistance to the response of pressure pulsations was discussed in detail.
    Download PDF (1108K)
  • Kohei FURUYA, Takuya YOSHIMURA
    2007 Volume 73 Issue 732 Pages 2263-2270
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    In Vibro-Acoustic System, [I] complex eigenvalue analysis and [II] CMS (unconstrained mode, without residual) are widely used for eigenvalue analysis. The method [I] needs huge computer resources, but it can obtain the exact eigen value and vector. In the opposite, the method [II] needs fewer resources, but accuracy of eigen-vector is not acceptable in some cases. To improve the accuracy, [III] CMS (unconstrained mode, with residual) can be used. But the method [III] deteriorates the advantage of the method [II], because physical degrees need to be remained in the equation of motion. In this paper, [IV] novel CMS method, based on unconstrained mode and residual mode, is proposed. The required computer resource is less than the methods [III], because the equation of motion is described on the modal coordinates. And the accuracy is better than the method [II]. In this paper, applying the methods [I] [II] and the proposed method [IV] to finite element models, it is shown that the proposed method is one of the effective methods for the eigenvalue analysis of Vibro-Acoustic System.
    Download PDF (1288K)
  • Shiro ARII, Hideyuki KATAOKA, Yoshitaka OCHIAI, Kensaku HASEGAWA, Toyo ...
    2007 Volume 73 Issue 732 Pages 2271-2278
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    Human voices are originated by vibration of vocal folds in the larynx. This vibration is induced by the airflow that is expelled through glottis, and causes a series of the pulses of the airflow. These pulses excite vocal tract and bring about the passive resonance of the vocal tract in all voiced sounds. Therefore, detailed study of this airflow is believed to be important to elucidate mechanism of human phonation. Thus in the present study experimental analysis of this airflow just above glottis was made to clarify phonation mechanism and seek better modeling of vocal folds, focusing on direct measurement of airflow velocity by means of a tiny hot-wire probe and simultaneous observation of vocal fold movement by means of a high-speed digital camera. The experimental results show that the periodic change of the airflow velocity occurs out of the phase of opening of glottis, though both have the same fundamental frequency. This fact is important since it gives a crucial hint for better simulation model of phonation mechanism.
    Download PDF (2479K)
  • Makoto SASAKI, Takehiro IWAMI, Goro OBINATA, Kazuto MIYAWAKI, Hiroki M ...
    2007 Volume 73 Issue 732 Pages 2279-2286
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    In this paper, we analyze a user-friendliness of wheelchair propulsion by using a dynamic index of the driving force. The index explains how much margin the user can take in joint moments to his maximum ability during wheelchair propulsion, and is expressed by the dynamic manipulating force ellipsoid (DMFE). The DMFE is illustrated from the measured values of maximum generated moments at the user's upper limb joints, and is used to understand quantitatively the margin of the user's ability for wheelchair propulsion. Based on the index, we have also proposed the concept of the driving force contribution figure (DFCF) to clarify how efficient the user accomplishes the wheelchair propulsion. The DFCF expresses the direction cosine of generated force on the handrim to the tangential direction. If the DFCF takes large value along the driving force direction, it means the applied force acts efficiently for wheelchair propulsion. In order to show the effectiveness of DMFE and DFCF, we measured the driving motion of the upper limb, hand force applied to the handrim, and the individual's muscular power characteristics for eight experienced wheelchair users. From the experimental data, it is shown that the users start driving the handrim at such posture where it is difficult to generate required hand force to drive the wheelchair. It is also shown that the user are driving the wheelchair taking the load of the upper limb and the efficiency of the wheelchair propulsion into consideration.
    Download PDF (1453K)
  • 6th Report, Gait for an Upward Step on Slope
    Shouichi MORIMURA, Shuro NAKAJIMA, Eiji NAKANO
    2007 Volume 73 Issue 732 Pages 2287-2294
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    A leg-wheel robot has mechanically separated four legs and two wheels, and it performs high mobility and stability on rough terrains. Although we have researched the adaptive gait for large rough terrains of the leg-wheel robot, it was limited to the terrain without a slant. To climb it over, the stability of the robot needs to be more considered. In this paper, the method to raise the stability for the upward step is described. If the robot needs larger stability at the upward step, the body trajectory has to go along to the terrain. In other words, the wheels have to touch the terrain. However the shape of the rough terrain is so complicated, that it is difficult to check with an external sensor. Therefore, the points are a judgment whether the wheels contact with the terrain and the control of the body. The robot judge whether the wheels contact with the terrain using rotation information of wheels or the load shearing ratio of legs. By deciding the body trajectory with these two methods, the robot can climb the rough terrain over more safely.
    Download PDF (1881K)
  • Yosuke MATSUKI, In HUR, Nobuyasu TOMOKUNI, Jian HUANG, Tetsuro YABUTA
    2007 Volume 73 Issue 732 Pages 2295-2304
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    In this paper, several models of approximating ZMP for humanoid are proposed without force sensors. Generally, ZMP is determined by using force sensor information. In this paper, this torque information is estimated by measuring motor-driving current. This paper discusses several estimation models whose results are compared by experiments. Furthermore, we examined effectiveness of proposed models. The results show that the proposed estimation methods are effective in semi-static condition. Specially, these proposed methods have advantages when a humanoid without a force sensor is controlled under change of gravity direction such as a slope condition.
    Download PDF (1603K)
  • Daisuke MATSUURA, Nobuyuki IWATSUKI
    2007 Volume 73 Issue 732 Pages 2305-2311
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    This paper describes the motion control of hyper redundant robots with a learning control scheme based on linear combination of error history. For a hyper redundant serial manipulator to achieve the motion of its end effector as a main task with a number of additional motions of other links as subtasks, several effective methods to set subtasks are proposed. The objectives of these methods are to reduce the interference between main task and subtasks, and to prevent from partially singular configuration of the manipulator. The backward learning scheme is also proposed to obtain the optimum initial configuration. Several simulations and experiments with a planar 10 R serial manipulator reveal that the proposed methods are effective and useful.
    Download PDF (1468K)
  • Hitoshi KINO, Dai NAKIRI, Tuyoshi NAKAMURA
    2007 Volume 73 Issue 732 Pages 2312-2319
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    The belt-formed pulley is a nonlinear spring device. Inserting the belt-formed pulleys into the route of wires, joint stiffness of the tendon-driven robot can be varied depending on internal force among wires. The system using belt-formed pulleys has many advantage such as low cost, low friction, light and so on, compared with other devices to vary joint stiffness. However, little is quantitatively known about static frictional property of belt-formed pulleys. In this paper, we propose the method of measuring static friction, and the static friction characteristic of the belt-formed pulley is shown through experimental result.
    Download PDF (1352K)
  • Nobutaka TSUJIUCHI, Takayuki KOIZUMI, Shinya NISHINO, Shigeki SHIRAI, ...
    2007 Volume 73 Issue 732 Pages 2320-2326
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    Recently, robot research that coexists with people and is helpful for them has been done. To coexist with people, it is necessary for robots to realize the same flexible motion as people. To grasp, a robot hand is required to control position accurately and treat the object flexibly. Additionally, when taking care of the elderly and patients, who are a typical example of personal service, safety and pliability are required because of much contact with people. Therefore, it is important to choose the proper materials, mechanics, drive systems, and control systems. Then, we propose pneumatic actuators as source of power of robot hand. But, to generate power, a past actuator needs a high compressed air. Then, in this research, a pneumatic actuator driven by low-pressure and low-volume is presented that is originally developed for driving a robot hand that works flexibly and is safer on the assumption of people contact. And this actuator is designed to get enough force to drive the hand in low-pressure. Because of the linear characteristics, this actuator can be easily controlled. And, the force control system that uses this actuator is constructed and the control performance to apply to the robot hand is examined. At the same time, five fingered robot hand using the pneumatic actuators is shown, and we show that the robot hand can do the same operation as man.
    Download PDF (1300K)
  • Yoshiaki HAYASHI, Motoji YAMAMOTO
    2007 Volume 73 Issue 732 Pages 2327-2334
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    When a positioning mechanism is used with human such as the case of human care machine, safety is the most important factor. To improve the safety, it is desirable that the mechanism has elasticity in itself. Authors have proposed a flexible positioning mechanism using wire constrains for such purpose. However, the mechanism does not realize multiple degrees of freedom motion. The paper thus proposes new positioning mechanism by multiple wires' constraints. The paper describes a motion analysis of the positioning mechanism which enables to form complex shapes of the mechanism. The mechanism consists of a flexible structure, support disks and multiple wires. As the flexible structure, a pneumatics hose is used. By changing the wire's length of the mechanism, the tip of the flexible mechanism can be positioned in three dimensional space. And also, intermediate points of the mechanism can be also controlled by manipulating wire's length. The relationship between wire's length and the position of flexible mechanism is complicated. In this paper, therefore, displacement of reference points of the mechanism is analyzed based on beam bending theory. Theoretical analysis is verified by an experimental flexible mechanism using pneumatic hose.
    Download PDF (1203K)
  • Application to Mechanical Design Problems
    Hiroyuki KAWAGISHI, Kazuhiko KUDO
    2007 Volume 73 Issue 732 Pages 2335-2342
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    A new optimization method which can search for the global optimum solution and decrease the number of iterations is described. The feature of the new method includes creating orthogonal arrays and changing the level value of design factors for every search step. The orthogonal array is selected based on the number of factors & levels, and the level values are changed based on the trend of the optimum solution. The performance of the method was observed on the optimization problems of mechanical design which involve discrete and continuous variables. The newly developed method is found to be very effective for searching the global optimum solution of the mechanical design problems with fewer numbers of the function evaluations.
    Download PDF (1227K)
  • Shigeo YANABE, Kazuhiro INOMATA
    2007 Volume 73 Issue 732 Pages 2343-2349
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    Various kinds of films and tapes are produced and widely used in many industrial fields. In order to raise productivity, both speed-up of line velocity and widening film width are highly requested. However, many technical problems occur in film production lines. The problems are skew, wrinkles, winding distortions, and so on. In this study, motion and deformation of a film which is transferred by four rollers including a misaligned roller are simulated by FEM software, in order to clarify characteristics of film skew and wrinkle occurence and effects of main parameters on these characteristics. The simulation results show that the film skews to the direction in which the roller distance decreases and the film approaches a certain position, when the movement of film width direction is constrained. While, it continues to skew to the opposite direction when the constraint is removed. The skew becomes larger as the width, thickness, Young's modulus of the film or the misaligned roller angle increases or as the roller diameter or roller distance decreases. A wavy wrinkle (trough) of the film due to misaligned roller runs on to the roller, and the width of the wrinkle becomes smaller because of the difference of the skew velocities of the two film areas separated by the wrinkle on the roller, and finally it becomes a folded wrinkle. Decreasing the friction force suppresses the folded wrinkles.
    Download PDF (1193K)
  • Takanori FUJIWARA, Shinya TSUKAMOTO, Masahiro MIYAGAWA, Akinori OMORI, ...
    2007 Volume 73 Issue 732 Pages 2350-2356
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    Twin axes synchronous controlled type CNC crankshaft pin grinder has been widely used, but grinding mechanism with this type of pin grinder is not cleared well. In this study, the grinding mechanism is analyzed, and it is found that the cylindrical plunge grinding process carries on. From the investigation of substantial surface speed of both the wheel and the workpiece, grinding speed ratio is formulated. Furthermore, a simulation method, which predicts the grinding results, is developed. In order to realize high precision pin grinding, two methods, which control workpiece rotation speed adequately, are proposed, such as the controlled grinding speed ratio method and the controlled residual stock method. From the analysis, it is made clear that stable grinding force and surface roughness are generated by the controlled grinding speed ratio method, and also high dimensional accracy will be realized by the controlled residual stock method.
    Download PDF (1213K)
  • In Case of Plastic Spur Gears Pair
    Akio UEDA, Masayoshi YOSHIHARA, Hideo TAKAHASHI, Ichiro MORIWAKI
    2007 Volume 73 Issue 732 Pages 2357-2366
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    The application of injection molded plastic gears becomes widespread ; e.g., audio/video equipments, office equipments, and electronic equipments, because of their quietness. In addition, plastic gears are widely used even for power transmissions. When plastic gears are used for power transmissions, the strength evaluation of the gears is one of the most important issues. However, the allowable stress used for the strength calculations has been evaluated in consideration of only atmospheric temperature. Therefore, the strength calculations are not so reliable, because heat generation due to both friction between meshing tooth flanks and hysteresis of material were not considered. If the actual temperature of meshing teeth would be evaluated in consideration of the heat generation, more reliable allowable stress of the material could be obtained. The present paper describes three-dimensional analysis of heat generation and heat conduction of meshing plastic spur gears. As a result, the calculated increase in gear temperature coincided with measured one. Then, the allowable stress of material could be evaluated more accurately.
    Download PDF (2196K)
  • Derivation of Strict Analytical Solutions of Transmission Errors with Radial Eccentricity
    Syuhei KUROKAWA, Yasutsune ARIURA, Takuya NAKANISHI
    2007 Volume 73 Issue 732 Pages 2367-2374
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    Exact analytical equations to analyze transmission error with radial eccentricity of an involute cylindrical gear pair are proposed. The equations include the amount and a phase angle of eccentricity of each gear in two dimensions and the relation between rotational angles is found an implicit function. The procedure to calculate concrete transmission error is shown shortly with those equations. Using best-fit procedure between measured and calculated transmission error of a gear pair whose number of teeth are relatively prime, it is verified that the equations have enough capability to predict actual transmission error with gear eccentricity. The best-fit procedure can be used as a kind of a high-pass filter to transmission error curve so as to analyze mesh frequency for example. The equations are also applied to predict transmission error of micro gear systems. For micro gears, manufacturing error and misalignment is rather larger than conventional sized gears. It is pointed out that this may lead larger transmission error than conventional one.
    Download PDF (1030K)
  • 3rd Report, Proposal of Simplified Design Method
    Fumihiro OHSHIMA, Hidehiro YOSHINO
    2007 Volume 73 Issue 732 Pages 2375-2380
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    It is a troublesome problem to decide design parameters for face gears. In this paper, a simplified design method for face gears is proposed. In the method, meshing of face gears at a certain gear radius is approximately substituted with that of the pinion and a virtual rack. Under this approximation, the shape of the virtual rack (pressure angle and module) is decided and both root and tip interference limits and tip pointing limit in face gearing are analyzed by investigating the meshing of the pinion and the virtual rack. Those limits were almost agreed with that of the strict calculation shown in the first report. As a result, it was found that the simplified method could be used to estimate efficiently the design parameters for face gears. In addition, an equation to give an offset to design a compact face gear set will be proposed.
    Download PDF (892K)
  • Masahiro HIGUCHI, Tomomi YAMAGUCHI, Noboru MATSUMORI, Hidekazu OGURA
    2007 Volume 73 Issue 732 Pages 2381-2386
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    A geometric modeling technique of the complex vitrified superabrasive stone surfaces has been developed for the purpose of describing their topographies with desired characteristics. It is based on the generating algorithms for random fractals, such as midpoint displacement and successive random additions, and yields a three-dimensional topographic map of the stone surface. Compari-sons between the simulated topographic map and the measured one show a good match ; the spatial distribution of abrasives on both the stone surfaces exhibits a fractal structure, indicating that the simulated stone surface is a good representation of the real one. Therefore, the computer modeling could be used advantageously when the designer makes drawings of stone surfaces
    Download PDF (1391K)
  • Takeshi UMEHARA, Tohru ISHIDA, Koji TERAMOTO, Yoshimi TAKEUCHI
    2007 Volume 73 Issue 732 Pages 2387-2393
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    In recent years, 3-axis control machining is generally performed in roughing process. However, 3-axis control machining is not efficient in case of roughing complicated shapes, i. e., parts with overhanging shape, because it requires to reset the workpiece. To solve this problem, 5-axis control machining has been developed. However, there has been no roughing procedure in 5-axis control machining. The study deals with roughing by 3+2-axis control machining, which performes 3 translational axis machining after determining a suitable tool axis vector by 2 rotational axis movement. For 3+2-axis control machining, the determination of tool axis vectors and tool diameters largely affects the rough machining time. The study proposes a method of determining the optimal tool axis vectors and selecting the tool diameters for efficient roughing. At first, the method searches candidate of tool axis vectors after calculating machinable area in each tool axis vector, applying the multi-stage decision process. Then, the method determines the combination of tool axis vectors and tool diameters, using a peformance index. The effectiveness of the proposed method was demonstrated by the machining experiment of an impeller.
    Download PDF (1375K)
  • Tetsuro YAMAGUCHI, Takuya SEMBA
    2007 Volume 73 Issue 732 Pages 2394-2400
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    A high-speed microfabrication technique using a focused laser beam was developed. A conventional CAD/CAM system was used, and the beam was scanned mechanically by attaching both optical mirror arrays and a focal lens to the column of an ultraprecision machining center. The measured groove width and pocket depth obtained by grooving and pocket machining were used as the tool diameter and the axial depth of cut, respectively. Glasslike carbon with a laser beam absorptivity of over 80% and a hardness of 650 MHv was employed as a workpiece. It was verified through a machining test that pseudo-3-dimensional concave prisms can be fabricated by digging square pockets with different square sizes but the same pocket depth in the negative Z direction. Shifting the laser's focal point away from the work surface can decrease the depth of the square pocket, so that high-speed roughing by adjusting the focal point on to the work surface and highspeed finishing by shifting the focal point away from the work surface can be conducted.
    Download PDF (1750K)
  • Haruo NAGATANI
    2007 Volume 73 Issue 732 Pages 2401-2408
    Published: August 25, 2007
    Released on J-STAGE: March 04, 2011
    JOURNAL FREE ACCESS
    When Hertzian theory is not available and it can be considered contact area is existing on the plane, numerical calculation is performed with superposing Boussinesq or Cerruti solution. In that calculation, generally, uniform pressure is assumed in element. On the other hand, MLMI method has spread, and contact pressure can be able to calculate with high accuracy because of using high-order interpolation of influence coefficient. But concerning sub-surface stress calculation, there are little announcement of solutions. Author developed both quadrangle linear pressure element and subsurface shear stress calculation method which uses linear pressure element. In this paper, author explains the derivation process of those. In addition, one case are taken up, and sub-surface shear stress by linear pressure element is compared with that by conventional uniform pressure element. As a result, in the case of uniform pressure element, the waving phenomenon of shear stress was seen near the contact surface. On the other hand, in the case of linear pressure element, correct solution was obtained in whole area.
    Download PDF (845K)
feedback
Top