著者

谷本 隆一 朝倉 孝征 今井 守之 鶴見 康昭 安田 仁彦

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.69, no.686, pp.2550-2555, 2003

---

In recent years one-box-cars are very popular in the market. So their interior noise level is required to be the same as that of passenger cars. To find an effective way to reduce the noise level, we studied why the noise level is high in a one-box-car as compared with a passenger car. We found that, because the diesel engine is placed under the front passenger seat, only narrow space is allowed between the engine and the engine cover, and this narrow space amplifies the noise. We confirmed by numerical simulation that this conclusion is appropriate. Based on the conclusion, we proposed to set up a silencer to lower the noise level, and found that it works effectively.

著者

川上 明 関森 秀伸 篠原 昭

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集C編 (ISSN:03875024)

巻号頁・発行日

vol.59, no.566, pp.3224-3229, 1993

---

In order to clarify the filament surface color for accident reconstruction, the experimental destruction of seven kinds of light bulbs was carried out by changing the time between the light bulb power off and bulb rupture. The following results were obtained. (1) According to the time, the oxidized color changes to dark grey, green, blue, purple, yellow, and light grey in this order. (2) The relationships among the time, color index number alloted to a typical filament surface color, and the light bulb's rated consumption of electricity were obtained as an approximate equation. (3) Elapsed time starting from the power off can be derived on the basis of the surface color or an approximate equation. (4) The oxidized color is very useful for traffic accident reconstruction. By means of this information along with conventional findings, drivers' behavior at the accident may be postulated more precisely.

著者

山口 勝美 菊澤 賢二 魏 源遷 洞口 巖 中根 正喜

出版者

一般社団法人日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.65, no.638, pp.4224-4229, 1999-10-25

参考文献数

5

被引用文献数

1 1

---

One of the authors invented a unique SiC whisker wheel in which the whiskers were aligned normally to the grinding wheel surface. In this paper, grindabilities of the SiC whisker wheel are investigated and compared with those of other wheels of SiC grains, Al<SUB>2</SUB>O<SUB>3</SUB> grains, as well as Al<SUB>2</SUB>O<SUB>3</SUB> long and short fibers which were also aligned normally to the grinding wheel surface, respectively. The main research contents grinding characteristics of a directionally aligned SiC whisker wheel such as material-removal rates, wheel-wear rates, integrity of the ground surfaces, grinding ratios and grinding efficiency. Furthermore, grinding wheels of whiskers and fibers have a common disadvantage : they tend to load easily. The authors introduced a simple method of loading-free grinding to overcome this propensity and investigate some related grinding characteristics under loading-free grinding conditions.

著者

灘野 宏正 中迫 正一 河野 正来 南 一郎 山口 博幸

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.70, no.690, pp.554-559, 2004-02-25 (Released:2011-03-04)

参考文献数

7

---

To clarify the wear resistance and seizure resistance of the vegetable oils with anti-wear additives of Dibenzyl-Disulfide (DBDS) and Phosphonic Acid-Dibutyl (DBPo), the four-ball tests were carried out under dip-feed lubrication using Soda-type four-ball machine. The width of the wear scar on the stationary balls lubricated with the vegetable oils containing DBPo additive was smaller than that without the additive, and was smaller than that containing DBDS additive. The seizure resistance of the vegetable oils with DBDS additive increased in following order : Turbine oil<Rapeseed oil<Soybean oil<Corn oil. On the other hand, the seizure resistance of the vegetable oils with DBPo additive increased in the following order : Turbine oil<Soybean oil<Corn oil<Rapeseed oil. The DBPo additive showed significant improvements in seizure resistance compared with DBDS additive.

著者

灘野 宏正 中迫 正一 河野 正来 南 一郎 山口 博幸

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.70, no.690, pp.554-559, 2004

---

To clarify the wear resistance and seizure resistance of the vegetable oils with anti-wear additives of Dibenzyl-Disulfide (DBDS) and Phosphonic Acid-Dibutyl (DBPo), the four-ball tests were carried out under dip-feed lubrication using Soda-type four-ball machine. The width of the wear scar on the stationary balls lubricated with the vegetable oils containing DBPo additive was smaller than that without the additive, and was smaller than that containing DBDS additive. The seizure resistance of the vegetable oils with DBDS additive increased in following order : Turbine oil<Rapeseed oil<Soybean oil<Corn oil. On the other hand, the seizure resistance of the vegetable oils with DBPo additive increased in the following order : Turbine oil<Soybean oil<Corn oil<Rapeseed oil. The DBPo additive showed significant improvements in seizure resistance compared with DBDS additive.

著者

御手洗 毅 山浦 弘 小野 京右

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.72, no.723, pp.3576-3583, 2006-11-25 (Released:2011-03-04)

参考文献数

5

被引用文献数

1

---

Rhönrad is a gymnastic equipment that is interesting in terms of dynamics and control. We presented an analytical model and governing basic equations of the Rhönrad mechanism with a human body model. Then, a control method named as Synchronous control was proposed. In this control method, the human body moves synchronously with the rotation angle of the Rhönrad. The motion caused by Synchronous control was numerically analyzed. After that, a standalone miniature Rhonrad robot that consisted of three gyro sensors, an actuator, a micro-computer and batteries was manufactured. The validities of the Synchronous control were shown by experiments with the robot.

著者

古林 卓嗣

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.66, no.641, pp.306-313, 2000-01-25 (Released:2008-02-26)

参考文献数

12

被引用文献数

1 1

---

A numerical study of self-acting gas-lubricated wave journal bearings is presented for their dynamic performances : HFW(self-excited half-frequency whirl)stability and dynamic response of an out-of-balance rotor. The study is conducted under practical operating conditions by means of a nonlinear orbit approach. Numerical examples of wave bearings are compared with those of herringbone-grooved bearings, and it is found that wave bearings give relatively favorable dynamic performances. Considering both HFW stability and dynamic stiffness, three-wave bearings are recommended for a practical use. However, it should be pointed out that HFW stability of wave bearings is quite sensitive to the wave amplitude, and also the synchronous orbit geometry of an unbalanced rotor supported on a wave bearing can be complicated out of plain circle.

著者

古林 卓嗣

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.62, no.604, pp.4636-4643, 1996-12-25 (Released:2008-02-26)

参考文献数

20

被引用文献数

1 1

---

A multigrid method has been introduced as a fast alternative to conventional relaxation methods for obtaining a solution to the Reynolds equation for self-acting gas-lubricated bearings. This paper verifies the procedure applied to both static and time-dependent dynamic analyses of plain-cylindrical journal bearings. The method gives successful results with less computational effort compared with single grid-oriented iterative methods. In addition, the new approach does not require a trial and error process to optimize the overrelaxation parameter unlike a successive overrelaxation method. The nonlinear orbit method which is an accurate but time-consuming transient analysis is expected to be reduced to a handy design tool for a complicated bearing system on incorporating the multigrid technique.

著者

古林 卓嗣

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.65, no.629, pp.330-336, 1999-01-25 (Released:2008-02-26)

参考文献数

12

被引用文献数

1 1

---

Both experimental and numerical studies are conducted on half-frequency whirl (HFW) stability of axially-grooved self-acting gas-lubricated journal bearings. The studies demonstrate that 8-grooved bearings are unconditionally unstable with usual bearing clearance and rotational speed. On the other hand, 2 grooved bearings operate stably at relatively low values of bearing number which are obtained with usual clearance and speed. The physics of HFW stability is attributed to the pressure distribution geometry. Further, as a result of extensive numerical simulations, it is found that 3 grooved bearings with groove width ratio to total width of 0.3 through 0.5 give favorable stability performance.

著者

川副 嘉彦 武田 幸宏 中川 慎理

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.76, no.770, pp.2646-2655, 2010-10-25 (Released:2017-06-09)

参考文献数

18

被引用文献数

1 1

---

There has been no question that some strings do provide a better grip than others, but that did not guarantee that the ball will produce more spin. Furthermore, experiments with hand-held rackets has been needed to solve the vexed question of how players can tell the difference between different strings when laboratory tests indicate that they should play the same. The previous paper of the authors made clear the mechanism of top spin performance in actual tennis and its improvement by lubrication of notched nylon strings according to the high speed video analysis on the court for the first time. It succeeded in an experiment showing that as the main strings stretch and slide side ways more, the ball is given more spin due to restoring force parallel to the string face when the main strings spring back and the ball is released from the strings. Since the notches of strings decrease spin rate, the lubricant materials are effective to the notched strings. Furthermore, it showed that the more spin results in the reduction of shock vibrations of the wrist joint during impact. This paper showed that the ball is given less spin rate (40% decrease) with the notched used strings compared to that with the new strings in the case of the nylon in this experiment, which has remained to be seen which gives more spin between new strings and the lubricated used strings, and it showed that the ball is given more extra spin (30% increase) by oil lubrication at the string intersections compared to that with the notched used nylon strings. Furthermore, it also showed that the used natural gut with notches decrease 70% of spin rate compared to the new natural gut without notches in the another experiment, which has remained to be seen whether the same results will be obtained. It also showed the difference of the topspin behavior when a pro and an amateur hits a ball.

著者

川副 嘉彦

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.58, no.552, pp.2467-2474, 1992-08-25 (Released:2008-02-26)

参考文献数

3

被引用文献数

2 4

---

There are a number of unclarified points regarding the impact phenomena and the optimum design of tennis rackets. The present study is based on the idea that the dynamics of a racket consists of the dynamics of a rigid body with an arm swing given at a grip as a boundary condition, an impact between a ball and strings with racket frame as an input force, and the structural vibration of the racket. In this paper, impact force and impact duration are investigated, considering the strong nonlinearity of the restoring force of ball and strings. Furthermore, the coefficient of restitution of the tennis racket is estimated using a personal computer on the basis of the impact phenomena and the experimental modal analysis. In order to predict the contact duration, which has an influence on the racket vibration, a simple impact model has been proposed, i.e., that the contact duration is determined by the natural period of a whole system composed of the mass of the ball, the stiffness of the ball and strings, and the reduced mass of the racket at the impact point on the racket face. The calculated results agree fairly well with the experimental results.

著者

川副 嘉彦 沖本 賢次 沖本 啓子

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.72, no.718, pp.1900-1907, 2006-06-25 (Released:2011-08-16)

参考文献数

15

被引用文献数

1 2

---

Players often say that some strings provide a better grip and more spin than others, but ball spin did not depend on string type, gauge or tension in the past laboratory experiment. There was no research work on the spin to uncover what is really happening during actual tennis impact owing to difficult experiment. This paper made clear the mechanism of top spin and its improvement by lubrication of strings according to the high speed video analysis. It also provided the more detailed explanations of spin behavior by comparison between a lubricant string racket and a famous 'Spaghetti strings racket' which was banned in 1978 by the International Tennis Federation since it used plastic spaghetti tubing over the strings to reduce friction resulting in the excessive spin on the ball. As the main strings stretch and slide side ways more, the ball is given more spin due to restoring force parallel to the string face when the main strings spring back and the ball is released from the strings. Furthermore, it showed that the more spin results in the reduction of shock vibrations of the wrist joint during impact.

著者

中山 信行 川本 広行

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.70, no.691, pp.804-811, 2004

被引用文献数

9

---

Formation of magnetic bead chains in a magnetic field was numerically simulated with the Distinct Element Method in order to apply for improvements of a magnetic brush development system in electrophotography. Simulated chain configurations, length and slant angle. and dynamic chain forming process were compared to the experimental results. The 2-D calculation could not simulate quantitatively well the chain configurations and the process, because the magnetic interaction between beads was under estimated due to the neglect of the interaction force between three-dimensionally distributed beads. On the other hand, 3-D calculation showed good agreement with experiments and it is concluded that 3-D calculation is indispensable for the quantitative evaluation. It was also confirmed that chain configurations were determined approximately to minimize its total potential energy given by the sum of magnetic energy and gravitational energy.

著者

今村 信昭 吉成 聡志 金子 真

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.59, no.564, pp.2395-2400, 1993-08-25 (Released:2008-02-26)

参考文献数

14

---

A simple torque sensor for a tendon-driven manipulator is proposed. The finger joint torque around a drive pulley is proportional to the tension difference on both ends of the pulley. With a coupling mechanism between tendons, this tension difference can be measured directly without detecting individual tendon tensions. The tension differential-type torque (T.D.T.) sensor is based on this idea and is useful for compensating for friction existing in the transmission system of the manipulator. However, so far, the T.D.T. sensor needs at least one tension pulley to support a driving tendon. This paper shows that it is possible to design a T.D.T. sensor without any tension pulley maintaing its basic principle. A torque sensor installation on the movable link makes it possible to eliminate the tension pulley and downsize it.

著者

章国 光 古荘 純次

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.61, no.592, pp.4687-4695, 1995-12-25 (Released:2008-02-26)

参考文献数

11

---

Friction in joint driving systems constitutes an important source of nonlinearity that makes it difficult to achieve high-precision control. In this paper, a method of estimating friction is proposed, which requires a joint torque signal, armature current and motor angular velocity. Considering disturbance rejection, a position control method is proposed as follows. Vibration is restrained by bandpass joint torque feedback, and high-precision position control is realized by friction feedforward compensation. Assignment of pole distribution is employed to determine three control coefficients, and the effect of disturbance rejection is compared and evaluated for three kinds of pole distributions. Properties of the proposed control are discussed, and experimental results are also Presented.

著者

橋本 卓弥 平松 幸男 辻 俊明 小林 宏

出版者

社団法人日本機械学会

雑誌

日本機械学會論文集. C編 = Transactions of the Japan Society of Mechanical Engineers. C (ISSN:03875024)

巻号頁・発行日

vol.73, no.735, pp.3046-3054, 2007

---

rights: 社団法人日本機械学会rights: 本文データは学協会の許諾に基づきCiNiiから複製したものであるrelation: IsVersionOf: http://ci.nii.ac.jp/naid/110006453882/

著者

橋本 巨 石本 早霧

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.63, no.607, pp.723-731, 1997-03-25 (Released:2008-02-26)

参考文献数

20

被引用文献数

1 1

---

Elucidation of the vibration mechanism of winged insect from the viewpoint of bionic design might aid in development and design of the driving systems for small- or micro-size actuators, because some flying insects easily overcome scale effects through use of wing vibration and achieve flight with high robustness and speed under conditions of large air viscosity. The aim of this report is to describe a theoretical model of the dynamics of relatively large-size insect wings powered by the direct-flight-muscle and of the dynamics of small-size insect wings powered by the indirect-flight-muscle. Based on morphological consideration of these two types of insect wing dynamics, the equations of motion for the wings are formulated. In the model, the dry friction-type and van der Pol-type forces are employed to power the wings of direct-flight-muscle-type insects, and the periodic impulsive force is assumed to power the wings of indirect-flight-muscle-type insects. Applying the equations of motion to the wings of insects such as dragonflies and flies, the wing vibration is analyzed under various conditions. From the numerical results, the vibration mechanism of two types of flying insects' wings is clarified.

著者

小泉 孝之 辻内 伸好 松原 真己 松山 幸司 相川 将隆 大島 裕子

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.77, no.777, pp.2018-2029, 2011

被引用文献数

1 5

---

Structure borne noise is dominant in vehicle interior noise as frequencies below approximately 300Hz. Spindle force is a critical factor in structure borne noise for vehicle interior noise. To research the vibration characteristic of a rolling tire is essential for prediction of spindle force. This paper describes vibration analysis of a tire on the static and operational condition. Firstly, the surface vibration velocities are measured in the operational condition to comprehend the vibration behavior of a rolling tire using the scanning Laser Doppler Vibrometers. Secondly, the tire vibration model based on the cylindrical shell theory is build up. The basic equation, including the effects of the initial tension and the Coriolis force due to rotation, is derived by thin rotating cylindrical shell model and Hamilton principal. The results of the experiment and the theoretical analysis for a rolling tire are presented. Consequently, it is found that same shape of traveling-wave modes occur for a rolling tire, and the excited frequency of forward wave is different from that of backward wave. Finally, it is revealed that whether the rotation effect have affect on the vibration characteristics of a rolling tire.

著者

山口 哲郎 仙波 卓弥

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.73, no.732, pp.2394-2400, 2007-08-25 (Released:2011-03-04)

参考文献数

10

被引用文献数

2 2

---

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.

著者

富岡 隆弘 瀧上 唯夫

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.70, no.696, pp.2419-2426, 2004-08-25 (Released:2011-03-04)

参考文献数

15

被引用文献数

3 11

---

This paper presents a method to suppress the vertical bending vibration of railway vehicle carbody by using carbody-truck (or bogie) interaction. It is shown from the running test result of an actual Shinkansen vehicle that the bending vibration can greatly be reduced when the rigidity of carbody-truck connecting elements in the longitudinal direction (i.e., rubber bush rigidity of traction links and anti-yaw dampers) Kx is set at the optimum value. The mechanism of the effect to reduce such vibration is analyzed theoretically. As a result, it is found that the truck frames and wheelsets act as dynamic vibration absorbers against the bending vibration of carbody. A formula to adjust Kx to its suitable value is derived. The accuracy and validity of the formula is evaluated numerically.