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Takashi MORIYA
Article type: Article
Session ID: 3204
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper describes the measurements of traction coefficient between paper-web and steel roller under various operation conditions. The uncoated paper (newsprint) is used as test web. In the measurements, the web is wrapped over the rotating roller with the surface velocities from 0 to 40 m/s. The web tension is applied by the weight at the edge of web and the traction force between web and roller is measured by the load-cell at the other edge of the web. The traction coefficients are, then, obtained based on the Euler's belt theory. Two types of grooved steel roller are used, and the web-wrap angle, web tension, web width, roller diameter are changed as operation parameters. From the measured results, the effects of such various operation parameters on the traction coefficient between web and grooved roller are clarified.
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Takashi SUZUKI
Article type: Article
Session ID: 3205
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Superconducting magnets on Magnetically Levitated Vehicle are vibrated to 308 Hz by the electromagnetic disturbance which occurs during the train passes over ground coils. This vibration is a reason for the heat generation of the superconducting magnets. Therefore, the decrease in the evaporation of liquid helium which is used for cooling the magnets is necessary for the stable driving. In this study, the frictional device which can measure the high-frequency friction from 100 to 300 Hz was developed. Furthermore, we will investige the influence of high-frequency friction on the evaporation of liquid helium.
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Hiroshi HARA, Hiromu HASHIMOTO, Masahisa FURUKAWA
Article type: Article
Session ID: 3206
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The measurement method for bearing characteristics such as air film thickness and pressure distribution of the thrust air film bearings are presented. The specially designed test rig is need to measure these bearing characteristics for a wide range of operation speed from 20,000rpm to 40,000rpm. Two types of bearings, pocketed and spiral grooved are used in the measurements. From the results, the accuracy and repeatability of the measurements are confirmed.
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Lizhi Zhang
Article type: Article
Session ID: 3207
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Numerical analysis of a circular hydrostatic thrust bearing with an elastic pad is performed. Under the conditions of steady state, axi-symmetry and fluid film lubrication, the Reynolds and elastic equations are solved numerically. The effects of the pad thickness and the supply pressure on the frictional torque, leakage flow rate, power loss and the bearing stiffness are examined. In conclusion, as the pad is thinner and/or the supply pressure is higher, the elastic deformation becomes marked, which results in the fact that the central gap, the stiffness and the power losses decrease.
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Yasushi KAN
Article type: Article
Session ID: 3208
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Principles of laser therapy in dermatology are that laser light of a specific wavelength, which is optimally absorbed by the target tissue, is given to the lesion area to increase tissue temperature. Exposure duration that is less than the time necessary for cooling of the target structure, that is, less than the thermal relaxation time of the target is needed. Usually this can be achieved by using very short pulses of light or Q-switched devices. Thermal relaxation time is defined as the time required for a target to cool from the temperature acquired immediately after laser irradiation to half that temperature. If the exposure duration to the laser is greater than the time required for heat diffusion to the surrounding tissue of the target, the thermal damage will be extensive and nonspecific. In this paper we have developed new type of laser therapy apparatus with laser scanning technology.
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Shinji MIYAMURA
Article type: Article
Session ID: 3209
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The design procedure of the traction roller increaser using wedge action is examined. The features of the increaser are that an input axis and an output axis are eccentric and to generate a contact force in proportion to a transmitted torque. The traction coefficient and the contact force at each contact point are changed according to the roller placement. The optimum arrangement to prevent a gross slippage at the contact point with the maximum traction coefficient is obtained by the static analysis of force balance. The rollers move during transmitting a torque by the contact force generated by the wedge action. Displacements of sun roller and wedge roller are obtained by FEM. When the input torque is 10Nm, the displacement of sun roller is in the range between 11 to 16 μm and that of wedge roller is about 0.28 mm. The increase rate of displacement of wedge roller becomes small with the increase in input torque.
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Fumihiko CHIBA
Article type: Article
Session ID: 3210
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The contact between tooth surfaces of the conical involute gear is a point contact. Therefore, tooth surface strength of the conical involute gear is smaller than the cylindrical gear. In the design of the conical involute gear, the evaluation of tooth surface strength is more important than bending strength. Tooth surface strength is evaluated at the allowable contact stress of tooth surface. A fatigue test is performed in order to evaluate this allowable contact stress. But, tooth surface is worn out during this test. Therefore, it is difficult to calculate the contact stress. Wear of tooth surface is influenced slip. Slip is evaluated the spesific sliding. But, there is no theoretical formula of the conical involute gear's spesific sliding now, so this theoretical formula is asked on an approximation target in this research. The relation between wear of the test gear and the spesific sliding is considered.
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Yasutaka Sato
Article type: Article
Session ID: 3211
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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A development of a lapping system for minute ceramics spheres was carried out. This work is consists of design and trial manufacture of a lapping machine and a development of evaluation methods of accuracy of minute spheres. The main elements of a lapping machine are laps and a lower lap has one or several u-grooves. For measuring roundness of spheres, an instrument was designed and manufactured. A method for measuring surface roughness of minute spheres by using a roundness curve was suggested.
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Takamitsu TANAGAKI, Hiroyuki KOUSAKA, Noritsugu UMEHARA, Takuya ISHII, ...
Article type: Article
Session ID: 3212
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Slide-screw (JSCR) test using resin nuts (nuts made of resin materials) was conducted to research the load capacity of resin nuts. A nut made of PI2 (the resin material containing PI: Poliimid and PTFE : Polytetrafluoroethylene) withstood more cycles of SCR test under the axial load of 600 N than nuts made of any other materials tested, and thus we concluded that PI2 was the best material for resin nuts with high load capacity. Furthermore, pin-on-disk (POD) test was conducted to know the relation between the friction coefficient and specific wear rate in SCR test and those in POD test for the same resin material. The results showed that the friction coefficients were almost the same (〜0.08) in both of the tests, while the specific wear rate in SCR test tended to become larger than that in POD test. The increased specific wear rate in SCR test was ascribed to the longer contact length (the length of contact area along sliding direction), which was 550 mm between the screw and resin nuts and 3 mm between the disk and resin pins, hi practice, the specific wear rates was decreased in the SCR test using the resin nuts with 18 mm contact length, which was shortened by cutting the screw thread away over 1.5 mm width at every 180 degree seen from the axial direction.
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Atsuyoshi MIURA, Keiji IMAI, Kengo OHNISHI, Atsushi INAGAKI, Hidetaka ...
Article type: Article
Session ID: 3213
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In this paper, we describe the design and application of a wearable device to prevent low back pain of caregiver. Due to repeated actions in unstable working posture at the bedside, caregivers often suffer low back pain. Hoist and other robotic appliance have been proposed, but have difficulty installing in Japanese housing condition. We propose a simple device that is wearable, lightweight, and lowers the physical burden without restricting other motions. The effect of using this device is evaluated by simulation and experiment. The electromyogram of the erector spinae muscle and the pressures at working points on the body are measured. The experiments showed that the device is effective.
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Masuji NATATSHI, Keiji IMADO, Atuyosi MIURA, Hiroomi MIYAGAWA
Article type: Article
Session ID: 3214
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Blood in lower position is said to be pumped up to a heat by calf muscle. So stretching of an Achilles' tendon is good for our health. Stretching is quite easy for a healthy person, but it is not easy for either the aged or a disabled person. Accordingly the hamstring stretching equipment was developed and evaluated. As the results of this research, the blood flow rate was closely related to the pedal angle of stretching equipment. Through our research, it was concluded that varying the pedal angle was recommended for the sake of increasing blood flow rate. The change of blood flow rate was not observed in stretching goods on the market.
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Tadaaki IKEHARA, Naoki Fukaya, Satomitsu Imai, Eiichirou Tanaka
Article type: Article
Session ID: 3215
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Ankle-foot orthoses (AFOs) are used in people who have difficulty of working as ankle contracture splints and foot drop splints. Although utilization of AFOs has been expanding, it is still questionable if functions and structures of AFOs are suitable. In this paper, a new active ankle-foot orthosis (AAFO), which is dynamically controlled linked with muscle activities, is proposed. To discuss functions of the AAFO, using the electromyographies (EMGs), muscle activities during dynamic balancing of a body and changing of muscle activities during fatigue are considered. As the results, it's shown that to assist femoris muscles additionally to the tibialis anterior muscle is important as the function of the AAFO.
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Satoshi SHIROGANE, Toshiaki TANAKA, Takashi IZUMI, Yusuke MAEDA, Tshik ...
Article type: Article
Session ID: 3216
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In order to improve the standing balance of elderly people, a standing balance control device has been developed. It was for vibratory stimulation on soles. In this study, we experimented both young adults and elderly people (10 young people, mean 24.4 years, and 9 elderly, 86.8 years). The subjects were instructed to stand relaxed, with bare feet and their eyes closed on the mat over a force platform. The four areas of feet stimulation were 4 big toes, heels, and metatarsal bones in both feet. This result showed that the vibratory stimulation on soles induced a displacement of the center of pressure to the opposite direction. The results suggest that this device can be for the sensory feedback system and guiding device for balance stability.
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Hiroki DAIRIKI, Mikiyasu HUZII, Keizou AWA, Takuzo IWATSUBO
Article type: Article
Session ID: 3217
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The first incidence factor of Pressure sour is persisting pressure that is continued. And, when shear force works on a skin surface in addition to pressure, producing complicated stress and pressure sore inside the living body, it has been researched in recent studies. It is mentioned as a problem that there is no clear evaluation about shear force, and that there is no prevention apparatus which consider a stress inside of a living body. Therefore, by experiment that the stress generated at the time of seating position using buttock models, we investigate about the influence that the external force affects the stress inside of the living body. And we examine the target value of shear force which considers the stress inside of the living body, and propose the optimal pressure sore prevention apparatus.
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Nobuyoshi MORITA, Tadashi KATO, Takashi MIZUNO, Bin FENG, Takao TORII
Article type: Article
Session ID: 3218
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper deals with a new bed for human body, called a multi-point press bed by air control. Air-cells and rubber-tubes are located lengthwise and sideways respectively, and pins are located on a point of the intersection of air-cells and rubber tubes. When pressures of the air-cells and rubber-tubes increase, the pins are moved up and balls on the pins push up the back of a human body. It is able to change the magnitude of the pressure to the back and the pressure distribution by controlling the pressure of the air-cells and rubber-tubes. This bed is useful for the prevention of bedsore or for the relaxation.
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Masaru HIGUCHI, Hitoshi NAKAMURA, Yukio TAKEDA, Koichi SUGIMOTO
Article type: Article
Session ID: 3219
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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alternative vehicle of a wheel chair that is driven by human cranking and actuators. One of the requirement to a power assisting system of the walking chair is that human power is utilized as much as possible while long distance movement can be achieved without much fatigue by human, hi this paper, we investigated kinetostatic characteristics of upper part of a human body through experiment. We proposed a model composed of 3-dof translations associated with the shoulder. 3-dof rotations associated with upper arm's flexion-extension, abduction-adduction and rotation, and a single dof associated with elbow's bending and stretching, hi the model, constraints on the maximum joint torque have been introduced in simultaneous actuation of multiple joints. Then, we applied the proposed model to design an appropriate axis position of the crank driven by human.
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SHIGEKI GOTO, MASAO TANAKA, TADAO YUUKI
Article type: Article
Session ID: 3220
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In recent years, electric wheelchairs have the development tendency of lightweight-izing and miniaturization. Users with the present model have dissatisfaction in the cruising range per 1 charge, the weight, the folding width and so on. We tackled lightweight-ized research of a frame, lightweight high capacity-ized research of a battery, and low noise-ized research of a drive unit in order to cancel such some dissatisfied points. The details of the above will be introduced hereunder.
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Yuki INOUE, Junichi KURATA, Hironobu UCHIYAMA
Article type: Article
Session ID: 3221
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Electric carts should be very useful as the life-supporting machine for elderly or physically handicapped people. Most of electric carts employ an oval steering handle mechanism, therefore a problem sometimes arises with the steering of electric carts. When the operator turns the handle, great flexion of the wrist joint occurs at both grips of the handle, causing distortion of the upper part of the body. To avoid this inconvenience in turning of the handle, the center of gravity of the cart and operator moved in the centrifugal direction. This movement may cause overturning with depending on the road situation and the force of inertia. To resolve this problem, we propose a new type handle, composed of four parallel links. The link-type handle mechanism, which can be operated with a straight-line motion, does not require bending of the wrist joint. This type of handle was quite comfortable for electric carts.
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Yuki OHTA, Hironobu UCHIYAMA, Junichi KURATA
Article type: Article
Session ID: 3222
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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A self-propelled type of wheelchair with hand-rims is diffused. Although the wheelchair gives users convenience, operator's motions to propel the wheelchair fatigue them. Recently the wheelchair has been equipped with a power assist control system, which mitigates fatigue and maintains athletic ability of upper-limb. However, this system is not general that corresponding to situations of a road surface and a change of operation. In this research, we propose the model of human-wheelchair system by acquiring the human characteristics in propelling wheelchair. And then, we propose the assist power control system based on the discussion about above model in which many factors on the interaction between human and wheelchair. We consider the propelling-force first as the factor depended on human. Subjects exercised the follow-up test fixing the wheelchair velocity to the reference velocity. We can perform modeling and verification experimentally in quest of a required element.
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Shinji HASHIMURA, Darrell F. Socie, Yukitaka MURAKAMI
Article type: Article
Session ID: 3223
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In this study, loosening-fatigue tests under small transverse vibrations have been performed to understand bolt behavior for the long life region. The results show that if a bolt has loosened within 10^3〜10^4 vibration cycles, damage such as crack nucleation at a root of the bolt thread is not observed, and loosening is due to bolt rotation. However, if loosening does not occur until approximately 10^5〜10^6 cycles, then a crack is observed at the root of the bolt thread in the all experiments. Loosening occurs due to loss of axial stiffness caused by crack propagation which then leads to bolt rotation. The results also show that the initial clamping force of bolted joint does not greatly influence the loosening-fatigue life. The amplitude of the transverse vibration force is the most significant influence on the loosening-fatigue life. This indicates that re-tightening a bolt during maintenance is not useful if the bolt has a crack.
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Susumu KUMAKURA, Kimiko SAITO, Daisuke IWAI
Article type: Article
Session ID: 3224
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The authors have proposed that one of the sources of self-loosening is due to the relative slips which are occurred by the radial deformations between the engaged screw threads and between the contact surfaces at the bearing surfaces of bolt and clamped parts when an external loading is applied to a bolted joint. In this study, the radial deformations of bolted joints fastened by a hexagon nut with flange and by a skirt nut with flange are calculated by Finite-element method. Using the calculated radial deformations, the self-loosening characteristics of the bolted joints are discussed. As the result, it is clarified that the self-loosening is not tended to be occurred in the bolted joint fastened with a nut of which the radial deformation is smaller.
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Shinji KASEI, Satoshi YOSHIDA, Hisanori ISHIBASHI, Manabu OKADA
Article type: Article
Session ID: 3225
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Our previous report suggests that the loosening rotation can occur when slip on bearing surfaces of bolt-nut joints, even if its magnitude is minute. It is the purpose of this report to continue considerations about this subject through loosening experiments which are carried out by adding transverse repeat loads. In the experiments, test joints with bolt-nut samples having duTerences of shape, pitch and surface treatment are employed. Experimental results shows that the loosening(loss of axial tension) exists in all test samples as far as the bearing-surface-slip occurs(even when its amplitude is 1〜2μm), and that the loosening rotation progresses in such conditions. The duTerences mentioned above only influences on speed of the loosening.
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Mitsuo KOBAYASHI, Hisami OISHI, Naotake NIWA, Michihiko TANAKA, Katsum ...
Article type: Article
Session ID: 3226
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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As a problem of the bolted joints, loosening of screw by impact external load and over tightening force of an impact wrench are often a problem. All are impact problems and it means that it is easy to move a bolt or nut by the friction of impact. In order to contribute to research of a bolted joints, this report considers impact friction from the amount of movements of the object to impact external load, and compares with the maximum static friction.
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Manabu OKADA, Shinji KASEI, Michihiko TANAKA
Article type: Article
Session ID: 3227
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Stress state in a region involving a bearing surface is an important subject to be investigated for higher reliability of bolted joints. This report shows equivalent stress distributions obtained from FEM analyses and particularly discusses stress states in both sides of bearing surfaces in cases of using several kinds of bolt It is found that a hexagon head bolt with flange with a proper concavity angle can bring improvements of unevenness of the stress distribution and strength reliability in the region. This effect is owing to uniforming of pressure distribution on a bearing surface caused by the concavity angle. However, application of this effect requires proper selection of this angle.
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Shuji HOSOKAWA
Article type: Article
Session ID: 3228
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The shape is not essentially symmetrical with the screw thread. The bending moment is caused in the bolt shank by the load distribution of screw thread which is not symmetrical in the tightening. It confirms that this bending moment is small by the analysis. However, the big bending moment in the bolt shank is caused by the inclination of the bearing surface at the tightening. The bending moment which influences relations between the torque on fitted portion of threads and torque on bearing surfaces is examined by the experiment.
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Ken-ichi Saitoh, Hiroki Matsumoto, Naoto Ebina
Article type: Article
Session ID: 3229
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Tapping torque, tightening torque and tightening force in the tightening of tapping screw are measured in consideration of the hole size for threading, the length of engagement and the condition of lubrication for the purpose of the optimum design of the joint with tapping screw. The results of these tests are compared with the theory proposed by G.W.Ehrenstein and et al.. As the result it is clarified that the tapping torque can be predicted fairy well, while the tightening torque and tightening force don't agree with these measurement, especially in case of large hole size.
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Masaya HAGIWARA, Shinya ITO, Masahiko HAMADA, Yoshio HIROOKA, Hiro OZE ...
Article type: Article
Session ID: 3230
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Tightening experiment for evaluating tightening characteristics is one of the most important issues to boost the reliability of bolted joints. However, the conventional testing machines have some problems in terms of the accuracy, the applicability and/or the rigidity to perform the experiment specified in ISO/DIS 16047. This study aims to develop the new equipment having the possibility to resolve such problems. The piezo electric force sensors to be used as the load cell and the torque cell have advantages that the rigidity is about 7 times lager than conventional ones, and that the accuracy and the linearity are very high and independent of the range to be measured. On the other hand, the characteristics of the senor eccentrically placed and preloaded have not been clarified. Experiments and analytical investigation using FEM have shown that the pressure distribution on the sensor surface affects the sensitivity value but that the linearity remains its ideal value, and it is concluded that the axial force sensor can be used as the load cell for tightening experiment. As for the torque measurement, it was clarified that the cross talk of the axial force on shear force sensors due to manufacturing and installation errors affects the virtual sensitivity. However, such a cross talk can be compensated by calculation, and finally the possibility to develop the newly designed load cell / torque cell unit with sufficient accuracy was confirmed.
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Masaya HAGIWARA, Takami OKUBAYASHI
Article type: Article
Session ID: 3231
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The revision of ISO 898-1 is now being worked out in ISO/TC 2/SC 1/WG9, in which tensile testing method for full-size bolts has been discussed to be specified. The tensile testing was originally proposed to check the yield strength and the ductility for the cold forged products (property classes of 4.8, 5.8 and 6.8) which cannot be measured by the test using machined test pieces, and the application is going to be expanded to all the property classes for better qualification of the property. The yield strength R_<pf> of full-size bolts is defined as the stress at 0.4% non-proportional elongation, and the permanent elongation at fracture A_f (%) is calculated based on the free thread length set to 1.2d. However, the testing conditions to obtain reliable results have not fully been discussed. The aim of this paper is to clarify the elastic-plastic behavior of full-size bolt in tensile test, and to propose the appropriate figures on values in accordance with those for machined test pieces. The results from FEM analysis show that the yield property is greatly affected by free thread length, and the load-elongation curve derived from FEM analysis represents the difference between the elastic-plastic behavior of full-size bolt and machined test piece well.
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Takumi TANDOU, Akihiko HASHIBA, Masamichi MORI, Tadatsu SATOMI
Article type: Article
Session ID: 3232
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The purpose of this study is to make clear analytically the fluctuation phenomenon of an aerostatic lead screw supposing to having an influence on its positioning accuracy. As the first step of its study, we succeeded measuring the fluctuation per 2π radian each screws experimentally, and considering theoretically. As the results, (1) The positioning accuracy was improved by using an air bearing effect, we call "Balancing effect". (2) It is assumed that the theoretical value of the female screw fluctuation is able to calculate by the balance of each axial loads.
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Peng ZHAO, Kazuya HATAKEYAMA, Tadaatsu SATOMI
Article type: Article
Session ID: 3233
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The contents of this research are the features of an air that flowed though orifice part. It is expected to measure the flux coefficient of orifice and the pressure distribution at the guiding surface experimentally, and create new formulas for it. When the calculation of static stiffness and its vibration of an aerostatic guidance are done, it is very important that the flux coefficient is presumed correctly. Especially the flux coefficient when the clearance less than 25 *m. In this study, the 30°slope orifice (Φ0.4mm) against guiding surface was designed and manufactured. The flux coefficient of this orifice will be calculated by experiment value.
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Kazuhiro YOSHIDA, Yeon-Oh JUNG, Takeshi SETO, Kunihiko TAKAGI, Jung-Ho ...
Article type: Article
Session ID: 3234
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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For microfactories and fluid microactuators, the authors have proposed a novel high output power micropump using inertia of pipeline that has an outlet pipeline element in place of a check valve and verified the effectiveness with a fabricated micropump. To increase the output power and to miniaturize the size, the paper investigates the optimal structure through simulations based on the proposed simple mathematical model with lumped parameters and experiments using fabricated micropumps with different sizes of the outlet pipeline. Also, the optimal diameter of the piston is investigated through simulations.
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Kazuhiro YOSHIDA, Tsutomu SOGA, Shinichi YOKOTA, Masashi KAWACHI, Kazu ...
Article type: Article
Session ID: 3235
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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A manipulator using novel hydraulic actuators named the MR (Magneto-Rheological) cylinders is developed. The MR cylinder is composed of a piston with electromagnets and a cylinder. MR fluid that is a functional fluid whose apparent viscosity can be controlled through the applied magentic field flows in the gap between the piston and cylinder and the differential pressure is controlled by the current applied for the electromagnets. The MR cylinder features compactness and large stroke. In this paper, a 2-link manipulaor using the MR cylinders is fabricated and the static and dynamic characteristics are experimentally investigated.
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Kenjiro TAKEMURA, Shinichi YOKOTA, Kazuya EDAMURA
Article type: Article
Session ID: 3236
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Soft robot inspired from natural systems is one of keywords in the robotic field in last decade. Accordingly, there have been developed many types of artificial muscles including pneumatic ones, ion-exchange polymer composite ones, polymer gels, shape memory alloys, and so on. On the other hand, using the electro-conjugate fluid, which generates powerful jet flow with high voltage supply (〜 kV), we can construct a compact pressure source. In this study, authors propose a new type of micro artificial muscle (< 1 cm^3) utilizing electro-conjugate fluid. The essence of this study is to develop the micro artificial muscle integrated with micro pressure source, which enables us to construct an autonomous system and/or artificial muscle array.
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Yosuke NAKAGAWA, Akira Saito, Takashi Maeno
Article type: Article
Session ID: 3237
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In this paper, we discuss the dynamic characteristics of ultrasonic motors (USMs). Though USM is said that its response is high, its dynamic characteristics are not clear now. First, we measured the transient response of bar-type USM by Laser-Doppler-Velocimeter. Changing the frequency of the applied voltage, we checked the relationship between frequency and overshoot, delay time of the rotational speed of rotor. Furthermore, we developed the mathematical model of bar-type ultrasonic motors in mechanical part. Developed model can be used for consideration of the interaction between rotor and stator, stick-slip distribution at the contact area. Using developed model, we calculated the history of driving force, distribution of the contact condition.
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Koichi SUZUMORI, Takefumi KANDA, Takashi NAGATA, Shuichi MITANI, Yusak ...
Article type: Article
Session ID: 3238
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper shows two types of new functional fluidic devices for chemical micro reactors; (1) an active catalytic system and (2) a micro flask. The active catalytic system consists of a micro chamber with two electrode thin films and micro catalytic particles of 100 to 500 micron meter in diameter. Electrostatic force enables handling micro catalytic particles in micro chambers to realize uniform mixing and acceleration of chemical reactions. A micro flask is also fabricated using piezoelectric materials, which oscillates to work as a micro agitator and an ultrasonic cleaner. The potentials of these new functional fluidic devices in micro reactors are discussed.
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Shuichi WAKIMOTO, Koichi SUZUMORI, Takefumi KANDA
Article type: Article
Session ID: 3239
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This study aims at development of soft intelligent rubber actuator of McKibben style. McKibben rubber actuator is an artificial muscle, which is pneumatically driven. At present, almost servo systems using this rubber actuator are driven with external potentiometer or encoder. So the systems tend to grow in size and to takeaway from compliance. In the first report, a soft displacement sensor was developed, and it was incorporated in rubber actuator. We named its actuator Intelligent Rubber-actuator. In this report. We fabricated a robot arm system configured by two Intelligent Rubber-actuators set antagonistically. Experiments with its system show that Intelligent Rubber-actuator has high possibility for application of several robot systems.
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Koichi SUZUMORI, Takefumi KANDA, Junichi TANAKA, Yukihiro MIYASHITA
Article type: Article
Session ID: 3240
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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We developed an intelligent pneumatic cylinder that realizes positioning servo control using a built-in reflective optical encoder. The developed cylinder is 133mm long, the cylinder's stroke is 40mm, and positioning resolution is 338*m. In this report, we report a new adaptive control algorithm for this cylinder. This algorithm is based on a way that controls switching timing of valve to minimize overshoot of cylinder rod. We compared the adaptive control with servo control from the view point of positioning and convergence speed. We realized high speed positioning control and convergence in any positions, which is difficult for conventional pneumatic cylinders.
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Youichi MOTOMURA, Takeo SUZUKI, Tadayoshi ITABE, Tomoaki YANO, Toshiyu ...
Article type: Article
Session ID: 3241
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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A Laser tracking system useful for measuring large structures and robots with high accuracy and wide-range measurement is required. To meet this requirement, we have developed two axes spherical motor type laser tracker, which gives the mirror of the tracking system three-dimensional motion. In this report, we introduce the design concept and the experimental results.
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Masahisa FURUKAWA, Hiromu HASHIMOTO, Yasushi Endo
Article type: Article
Session ID: 3242
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper presents the numerical analysis modeling of thrust air bearings and its application to optimum design. In the modeling, the boundary fitted coordinates and divergence formulation method are suitably combined for improving the applicability to the complicated bearing geometry, such as spiral grooved and herring bone bearings. The load capacity, friction torque, spring and damping coefficients are obtained as a function of design variables such as groove depth, groove angle, bearing width ratio and groove width ratio. The calculated results are compared with the experimental results for the verification of validity. Then, using the numerical method, the design variables which optimize the objective function defined as the ratio of friction torque to spring coefficient are determined for a wide range of rotational speeds under various constraints by applying the hybrid optimization technique combining the direct search method and SQP. Some numerical examples are given in the graphical form.
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Hiromu HASHIMOTO, Hiroshi HARA, Masahisa FURUKAWA
Article type: Article
Session ID: 3243
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The measurement method for bearing characteristics such as air film thickness, friction torque, spring and damping coefficients and pressure distribution of the thrust air film bearings are presented. The specially designed test rig is need to measure these bearing characteristics for a wide range of operation speed from 20,000rpm to 40,000rpm. Two types of bearings, pocketed and spiral grooved are used in the measurements. From the results, the accuracy and repeatability of the measurements are confirmed.
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Ryozo NIMOTO, Eiichirou TANAKA, Hideo TAKAHASHI
Article type: Article
Session ID: 3244
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The meshing of teeth of crossed helical gears theoretically takes place at a point. The contact point extends over a small ellipse due to elastic deformation under power transmitting. Hence the contact stress between the tooth surface is comparatively high. Furthermore, the sliding velocity on the tooth surfaces is higher than for other kinds of gears. For these reasons, this meshing are able to carry only very small loading. Tb guard against the danger of surface failures, it is necessary to have a means of calculating the contact stress states. The details of variations of the contact ellipse on an imaginary rack of crossed helical gears were observed.
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Takeshi WATANABE, Yoshikazu MIYOSHI, Kohei SAIKI, Yoshihiko TAKENOUCHI
Article type: Article
Session ID: 3245
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Gear noise has been becoming a great influence on the comfortable driving, also lightweight transmission is required. Therefore, it is necessary to clarify the physical mechanism of each resonance peak by actual measurement. In this research, a helical gearing apparatus is developed to measure the 3-dimentional vibration of gear and gear shaft. As the result, gear mesh vibration and elastic bending vibration of gear shaft resound on low rotational speed and it causes some characteristic peaks of transverse vibration. Especially, if the drive and driven gears have different shape and weight, both gears vibrate simultaneously along Line of action (LOA), however, each gear vibrates individually at right angles to LOA.
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Masayasu HATAZAWA
Article type: Article
Session ID: 3246
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The viscosesl, in which sealant filled in the clearance between screw shaft and the housing is pressurized by screw pump effect, is a kind of non-contact seal. Some theories of their sealing performance both in laminar and in turbulent region have been proposed. But most experimental results of sealing performance are inferior to theoretical ones. Experiments and simulation on pressure distribution of the viscoseal are performed. Also, effects of screw shaft inclination on their performance are discussed.
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Yooichi MURAI, Yasuo FUKUSHIMA, Shigeru ARAI, Haruo MIURA
Article type: Article
Session ID: 3247
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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We carried out basic investigations of seal-rings for high-pressure hydrogen reciprocating compressors used in hydrogen fueling stations, that supply high-pressure gas for fuel cell automobiles. In the first step of this investigation, we compared the characteristics of copper alloys, engineering plastic materials (polyether ether ketone), and diamond-like carbon films on SUS304, in load carrying tests and wear tests with mock-up reciprocating equipment. We discovered that copper alloy has a low friction coefficient and low wear rate. Secondary, we set four seal-rings, made from this copper alloy, in series and measured the equipment sealing characteristics in mock-up seal-ring. In one of the results, a steep pressure drop in a specific seal-ring, instead of a gradual drop in each seal-ring. This phenomenon occurred because of a leak through the space between the seal-ring and the reciprocating rod.
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Hiroyasu YAMAMOTO, Yusuke NAKAMURA, Toru FUKUZAKI
Article type: Article
Session ID: 3248
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In order to clarify the effect of contact load and lubrication conditions on wear amount and plastic flow in the subsurface layer of a contact rotating roll, the experiments for contact rotating of two disks were made under the lubrication condition of water and 5% solution of lubricant. As a result, it has been found that the wear amount of a roll disk decreases with the increase of contact load, and that the engineering shear strain on the surface of the roll disk under the condition of water is about one and a half times larger than that under the condition of 5% solution of lubricant in the case of 12.5kN contact load.
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Hiroyoshi Tanaka
Article type: Article
Session ID: 3249
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In this study, effects of surface temperature on the pitting fatigue life with two-disc machine were investigated. The pitting fatigue life can be described from the degree of separation, so (1) The extent of metallic contact of two disc surfaces (2) traction curves, (3) surface temperature were measured with some lubricants containing of viscosity index improver(VII). These results should be estimated comprehensively. The results were summarized as follows. (1) The VII additives can improve the degree of separation compared with its base oil, but not with the same viscosity paraffin oil. (2) The VII containing oils increase the surface temperature compared with the base oil or the same viscosity paraffin oil.
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Toshiharu KAZAMA, Mitsuru FUJIWARA, Shin'ichi MITSUMOTO
Article type: Article
Session ID: 3250
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Temperature of a swash plate of an axial piston pump was measured and seven kinds of hydraulic oils were assessed. Five thermo-couples were embedded in the swash plate and one thermistor was placed in the suction conduit of the pump. The test oils were mineral and synthetic type oils with the viscosity grade of 32 to 46, adding friction modifiers. The maximum discharge pressure was 20 MPa, discharge flow rate was 161/min, and the inlet oil temperature was 30℃. At the atmospheric to maximum discharge pressures, the temperatures, flow rates and the torque were measured, and then the swash plate temperature rises and the pump performance curve were obtained. In conclusion, i) A low viscous oil with the friction modifier gave a lower temperature rise; ii) As the discharge pressure increased, the temperature rises became larger, and iii) The types of the oils tested less influenced the performance curves.
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Yuji YAMAMOTO, Hideo SHIBUTANI, Yoichi TAKAHASHI, Osamu HORIUCHI, Hiro ...
Article type: Article
Session ID: 3301
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper describes about a development of granulated abrasive wheel and the polishing characteristics of granulated abrasives wheel. The granulated abrasive wheel was mad for trial by the next processes. At first, abrasives were mixed with sodium alginate aqueous solution and secondary it was dropped in the calcium chloride bath. Finally, granulated abrasives were fixed with the binder. To evaluate the feasibility of the wheel, the granulated abrasive wheel performed grinding test of fused silica glass.
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Masayoshi MIZUTANI, Fumihito MAEHAMA, Jun KOMOTORI, Kazutoshi KATAHIRA ...
Article type: Article
Session ID: 3302
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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To clarify the effects of ELID (Electrolytic In-process Dressing) grinding on fatigue properties of a stainless steel (SUSS 16L), bending fatigue tests were carried out. To measure the hardness of ground surface, nano-hardness tests were performed by using a Nano-Hardness Tester (NHT). Residual stress of the specimen surface created by grinding was also examined by an X-ray diffraction technique. Results show that the ELID grinding improves fatigue properties of metallic materials; this process increases fatigue strength of the stainless steel. This is due to the existence of hardened layer and compressive residual stress. Consequently, the ELID grinding method appears to offer significant future promise for use in biomaterials and other engineering components.
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Takanori FUJIWARA, Masahiro MIYAGAWA, Shinya TSUKAMOTO
Article type: Article
Session ID: 3303
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In this study, the grinding mechanism of the crankshaft pin carried out by the CNC crankshaft pin grinder, is theoretically analyzed. By this grinder in the grinding process, the geometrical interference form varies continuously, because the substantial grinding speed at the grinding point changes due to the revolution of the pin. Therefore, the grinding mechanism in the CNC camshaft pin grinder is made clear, from the investigation of the various relation of the speed at the grinding point. Furthermore, the control methods of the constant grinding velocity ratio and of the constant residual stock are proposed in order to regulate the variations of the grinding results. In these methods, the journal rotation angle velocity is controlled to maintain the size of the geometrical chip shape constant, and the high performance pin grinding ability is verified.
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