Three-dimensional, finite element method and a face-contact model of the gear teeth are combined with a mathematical programming method to do loaded tooth contact analysis and mesh stiffness calculations of a pair of spur gears with machining errors and tooth modifications. Effects of the tooth profile deviations, tooth pitch errors, tooth profile modification, tooth lead crowning and relieving on the mesh stiffness are investigated. It is found that the tooth profile deviations, tooth pitch errors and tooth profile modifications have significant effects on the mesh stiffness. It is also found that the lead crowning and relieving make the mesh stiffness smaller, but have no effects on load sharing ratios of the gears. Since the lead crowning makes the maximum contact stress of the teeth much greater and the lead relieving make the teeth have edge loads, it is necessary to pay a special attention to the quantity of the lead crowning and the length of the lead relieving, not to make the quantity of the crowning and the length of the relieving too larger.

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The life of the plastic crossed helical gears depends on the meshing teeth temperature, since the physical property of the plastic changes with the temperature. Therefore it is important to decrease meshing teeth temperature, in order to increase the life of the plastic crossed helical gears. There is probability that meshing teeth temperature of crossed helical gear which is combination of plastic and metal gear lower than meshing teeth temperature of the crossed helical gear which is combination of plastic gears, since the thermal conductivity of the metal is higher than the thermal conductivity of the plastic However, the estimation method of the meshing teeth temperature of the crossed helical gear which is combination of plastic and metal gear is not reported. In this study, the meshing teeth temperature of the crossed helical gear which is combination of plastic and metal gear was investigated experimentally Experiments were carried out under no-lubrication conditions. From the result of the experiments, we obtain the following results, (1) Meshing teeth temperature of crossed helical gear which is combination of plastic and metal gear is lower than meshing teeth temperature of crossed helical gear which is combination of plastic gears. Therefore, the life of the plastic crossed helical gear may increase by combining with metal gear,(2) With regard to the crossed helical gear which is combination of plastic and metal gear under no-lubrication conditions, the effect of the operating conditions and axial angle on the meshing teeth temperature can be evaluated by the mean flash temperature.

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The fatigue life of injection molded plastic gear is greatly affected by the plastic material and temperature. Because the stiffness of plastic depends on its material and temperature, and plastics are viscoelastic materials. On the other hand, natural materials are used to focus on the ecological recycling. The rice hull is a residual product of rice, and it contains natural silica about 20wt%. The authors focused on using the Rice-Hull-Silica-Carbon (RHSC) as a reinforcing material in plastic. In this study, Polyacetal (POM) and POM filled with RHSC, were used for the materials of test gears. The fatigue life and noise of test gear were investigated under fixed rotational speed and some torque. Then, the effects of RHSC on the fatigue and noise of plastic gear were studied experimentally. From the discussions, it seems reasonable to conclude:(1) In a RHSC-gear, RHSC-particles exist on a tooth surface, and these grind a tooth surface of partner. The size of grinding trace depends on the size of RHSC-particle. (2) The sliding-sound of tooth is lower when a tooth is worn out. However, since a tooth will be more worn if RHSC-particle is large, the sliding-sound increases.

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Gears with a different tooth profile from an involute curve might be effective for the reduction of energy loss in the running condition Sine-curve gears, of which teeth surfaces are formed using a sine-curve rack, have smaller sliding between tooth flanks than involute gears. The present paper describes the tooth surface temperature and the power transmission efficiency of plastic sine-curve gears The running tests for sine-curve gears and involute gears were performed under various running conditions. Test results showed that the power transmission efficiency of a sine-curve gear is higher than that of involute gears.

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Application of POM gears becomes widespread because of low manufacturing costs, light weight, and chemical stability However, POM gears cannot be operated in severe conditions due to tooth breakage and melting. In the present paper, deposition methods of DLC films for POM gears with UBM sputtering were investigated to improve tribological performance and endurance of POM gears. As a result, cleaning using organic solvents and deposition of Cr/C gradient interlayer enabled DLC films to be deposited on POM gear flanks However, deposited DLC films were not improve endurance of POM gears According to observations of tooth flanks, it was found that DLC films on tooth flanks were disappeared on contact area with sliding. To investigate deposition methods would permit the optimum ones to be found for a DLC film wear resistance of POM gears improving.

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The simulation of rolling contact fatigue strength of traction drive elements was proposed. It can consider the effect of size and distribution of inclusions in the material and the traction force generates on the contact surface. In this study, the rolling contact fatigue strengths in case of using ordinary and clean steel were estimated by using that simulation. The distributions and the densities of inclusions were decided by the observation of specimens. In case of using ordinary steel, 858 MPa of average rolling contact fatigue strength was obtained. The case of clean steel, 944 MPa was obtained, and it exceled 10% than the case of ordinary steel.

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The purpose of this research is to develop the high strength gears that can contribute to downsizing and weight saving of gear system. We verified the effects of temperature on micro-pitting strength by using two roller testing machine We confirmed that (1) At the end of the test, damage ratio was 7〜8% when the temperature of the test roller was 47 ℃ and 101 ℃. On the other hand, damage ratio was about 20% when the temperature of the test roller was 140 ℃. (2) Due to the rise of the temperature, micro-pitting strength fell to a low level.

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In previous studies, we have developed an involute-cycloid composite tooth profile gear, and proved that the gear has larger bending strength, greater surface durability, and higher power transmission efficiency than involute gear. However, wear resistance of the involute-cycloid composite tooth profile gear has not been clarified yet. Therefore, we investigated wear of the gears using a power circulating-type gear testing machine. In the experiments, we measured wear depth and tooth profile error for the involute-cycloid composite tooth profile gear and the involute gear Moreover, we developed a program to calculate the wear of these gears. Then we compared the experimental data with the calculation results. It is concluded that the involute-cycloid composite tooth profile gear has greater wear resistance than involute gear, and the calculation results are in agreement with the experimental data.

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In some cases where there is the deterioration of the vacuum tube oscillation in the induction hardening apparatus, poor hardened gears are usually produced by the induction hardening apparatus of deteriorated vacuum tube oscillation. Such poor hardened gears may be improved by re-hardening with the induction hardening apparatus of new vacuum tube oscillation. In this paper, measurements of the profile, the hardness and the micro-structure of hardened layer and the bending fatigue test were earned out for the poor induction hardened gears and the re-hardened gears. The validity of the re-hardening treatment for the poor induction hardened gear was determined to a considerable extent.

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Foreign object damage is attributed to dents formed by foreign objects such as debris and wear particles. It is important to clarify the behaviors of dent formation and stresses on contact surfaces in order to investigate the influence of foreign object damage on surface durability. Plastic deformation and formation of crown shape dent on contact surface were analyzed with elasto-plastic FEM analysis. A semispherical foreign object with a diameter of lOOμm was pressed against an elastic-perfectly plastic solid surface with a yield stress of 800 MPa or 1600 MPa Dent formation, crown height, contact pressure, and subsurface stress calculated with rigid foreign object were compared with those with elastic-perfectly plastic one.

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In order to obtain the high surface durability of power transmission gears and to promote environmental protection, the tooth surface-finishing method using a plastic material was developed. In this paper, the influence of machining condition on tooth surface texture of case-carburized gears was studied. First, the various plastic materials could be obtained by mixing the white petrolatum with the volcanic-ashes in different particle sizes Secondly, the tooth surface of case-carburized gear was finished by use of a plastic material. Thirdly, the tooth surface was investigated by using a scanning electron microscopy and a surface texture measuring instrument. From these experiments, the following results are obtained. By applying the designed tooth surface-finishing method in the case-carburized gear tooth, the randomly-rough surface after heat treatment process almost become smooth. In the case of finished tooth surface, it is found that the values of three dimensional roughness parameters decrease with the increase of finishing distance and particle size of the volcanic-ashes.

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Gear skiving is not a new method. It is a gear cutting method with a gear-type tool in which work- and tool-gears mesh with each other with a shaft angle between their axes, and the tool-gear is fed along the work-gear axis. The shaft angle yields flank sliding along a gear axis which can play a cutting action. Therefore, skiving can be expected to realize a high productive gear cutting method especially for internal gears. The present paper describes an example of tool edge shapes which are calculated on the basis of the gearing theory.

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Although the gearing of crossed helical gears theoretically takes place at a point, the contact point is spread over an elliptical area due to elastic deformation under loading. The contact stress between the tooth surfaces is comparatively high for this reason Furthermore, the sliding velocity on the tooth surfaces is higher than for other gears. For above mentioned reasons, crossed helical gears able to carry only small loads. To make the most of its good features, it is important to improve the load carrying capacity of crossed helical gears. To make the most of its good features, it is important to improve the load carrying capacity of crossed helical gears. Two factors, that is, high sliding velocity and high contact stress seem to be important, but here we limit the discussion to the contact stress state. It is worthwhile to examine the subject more closely. Also, it is important to understand the meshing geometry of crossed helical gears, since it forms the theoretical basis of the meshing geometry of other types of gearing. The contact ratio is an important criterion of load carrying capacity. The contact ratio increases as the normal generating pressure angle decreases. A high contact ratio was able to be obtained by adopting low normal generating pressure angle. The purpose of this paper is exactly to investigate the contact stress states on the tooth surface of crossed helical gears.

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The purpose of this study is to improve total regenerative energy of power-train driven by two motors by concurrently determining appropriate shift condition of Continuously Variable Transmission (CVT) of push belt type under braking. To improve the total regenerative energy, segmental change of regenerative energy by the motor was considered due to the change of number of revolutions. The initial speed-ratio of the CVT was changed to modify the path of speed-ratio where high speed-ratio was kept for long term during braking. In experiments and simulations, total regenerative energy was evaluated when speed of the vehicle was reduced from 40km/h to Okm/h with -1.23m/s^2 of acceleration and the change from 0.6 to 1.4 of the speed-ratio of the CVT, respectively. It is found that maximum improvement of total regenerative energy was obtained when initial speed ratio of CVT was i_<Cl>=0.84. The regenerative energy of the power-train driven by two motors was improved approximately 122% and 35.4% determining appropriate shift condition of CVT, compared with those of conventional power-trains driven by one motor and even by two motors transmitting through gears (i_g=0.6), respectively.

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A high-rate reduction ratio is obtained by using two kind of laminated planetary gear systems. One layer's planetary gear system is little difference in tooth number or diameter from opposite layer's planetary gear system. The input rotation is from sun gear and the output is not obtained from planet gear's carrier. The reduction revolution is given by the difference between the most out side two rings of internal gear. The first reduction mechanism of laminate type planetary gear is manufactured in one tooth difference In this case the sun gear exist on only one layer and opposite layer have no sun gear because of its each gears' tooth becomes a prim number. Then the planet gear have to be fixed through both layer and delivered on one earner, so named as perfect and imperfect layer lamination. The prime number tooth planet gear delivered on one earner as perfect layer's planet gear position. This manner requires quite fine tooth generating accuracy. This accuracy accomplishment were so difficult as to reach up to 30 % in the efficiency and the noise diminishing. Therefore the second type of perfect and perfect layer were designed, and manufactured in quite small difference in gear diameter. Here state those possibilities of more advanced thin and light weight reduction mechanism by lamination of two kinds of planetary gear system, and circumference multi v-grooved friction wheel planetary layer system, also in addition clutch mechanism for the output layer simultaneous-alternatively exchanging into rotation and counter-rotation on one way sun gear revolution direction.

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Face gears can be substituted for bevel gears or hypoid gears. They can be used only in restricted applications today. Recently, a new application of face gears for helicopter transmissions has been proposed and face gears have attracted special interest. The geometrical design method for face gear was also clarified. Especially, it was clear how the inner and outer diameters of ring gear are defined. In this paper, for avoiding the influence of machining and assembling error on tooth bearing, the design method of point-contact face gear with helical gear as pinion is described Concretely, the gear tooth surface is generated by the cutter gear with the same module as and larger number of teeth than the pinion. A numerical example was presented based on the proposed method and the method was validated by tooth contact analysis (T.C.A).

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Influence of alignment error and manufacturing error in face gear engagement is reported. Although many face gears are used for the fishing spinning reel, the time required for adjustment during the assembling of a reel has been increasing when the tooth flank is not modified (1). According to this report, it was shown when a suitable tooth flank modification was applied to a manufactured tooth flank by a pinion gear cutter, the influence of alignment error decreased. There are three types of alignment error "Height error", "Offset error" and "Difference error". In a mass production, however, it is also necessary to take into account manufacturing error of a pinion gear and a face gear as some factors which affect the rotation feeling of a reel in addition to alignment error. In this research, those factors of manufacturing error were considered in the assembly error and the factor effect analysis was conducted by 3D simulation. The problem when the modified tooth flank was adopted to real products was verified in advance.

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Let the marine transmission using conical gears be called "Conical Drive Marine Transmissions". For these years, marine transmissions having high capacity have become an urgent need. To answer this need, it is necessary to increase both the tooth surface strength and the bending strength. The authors have already developed concave conical gears which made it possible to increase the tooth surface strength. And now, as the gears which makes it possible to increase the bending strength, we invented a new type of concave conical gear, called "Hyper Conical Gear". That is to say, the Hyper Conical Gear is the gear having both the increased tooth surface strength and the increased bending strength. This research aims at developing the design and production system of the Hyper Conical Gear. In this report, the design and production method of Hyper Conical Gear used for marine transmissions is presented. First, the relationship between the basic dimensions and the mounting dimensions of Hyper Conical Gears used for marine transmissions is obtained. Thus, the design procedure of Hyper Conical Gears is presented Finally, test gears are designed and made for trial, the tooth bearing of the test gears measured and compared with analytical ones. And, it is proven that the design and production method of Hyper Conical Gears used for marine transmissions have the availability.

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Let the marine transmission using conical gears be called 'Conical Drive Marine Transmissions". For these years, marine gears having higji capacity have become an urgent need. To answer this need, it is necessary to increase both the tooth surface strength and the bending strength. And now, we invented a new type of conical gear, called "Hyper Conical Gear". That is to say, the Hyper conical gear is the having both the increased tooth surface strength and the increased bending strength. And for the design of hyper conical gear which can realize high performance, development of tooth surface analysis of hyper conical gear is indispensable. This research aims at developing the relative tooth surface analysis of a pair of hyper conical gears. First, ease off of hyper conical gears is calculated by means of a tooth contact analysis. Thus, we get it m the whole tooth surface and called "relative tooth surface" Secondly, gear tooth action is analyzed. Finally, compared to the experimental tooth bearing and the theoretical tooth bearing obtained from relative tooth surface, and clarify the validity of this analysis.

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The conical involute gears have been applied to automotive parts such as 4WD transfer. To apply for automobile, high capacity and higher quietness are required. In general, the tooth contact of conical gear pair is point contact, hence the large ease off happens even though each tooth surface has no manufacture error. From this characteristic, the tooth surface durability of conical gear pair is thought to be generally small. To clarify the tooth surface durability of conical gears we developed the evaluation method of tooth contact stress distribution on conical gear surface taking an ease off shape and a tooth surface modification into consideration and evaluated a pitting test result by this method. The relationship between the maximum contact stress and pitting life can be put on the pitting S-N curve of cylindrical gears. The edge contact found often cylindrical gear surface at heavy load isn't found on conical gear surface because of large ease off shape.

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When the simple equipment which moves with cross type 4 arms goes up stairs, drive torque changes with the rotation positions of an arm. Therefore, when designing the actuator of simple equipment, the motor set by the maximum torque needed for the axis of rotation will be selected. However, if selection of a motor is united with maximum torque, futility will arise in the size and energy consumed of equipment. This research examined how to equalize this changing driving torque with the noncircular gear. As a result of examination, the shape of the noncircular gear of decreasing the maximum of drive torque by not less than 30% was able to be searched. However, as a result of the experiment, the problem occurred in engagement of the noncircular gear, and the countermeasure became a new subject. In conclusion, the countermeasure was able to consider how to tie the noncircular gear to three.

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The development of new hourglass worm gear set which wheel material was hardened steel and its surface was ground by CBN deposited grinding wheel was challenged. The result performance of load carrying capacity and efficiency were not so good as expected, but the performance of the angular transmission error was astonishingly well. And the reason was searched and reported here.

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The purpose of the present study is to improve the performance characteristics of the electric sliding contacts and to extend their lifetime by using the rotating porous disk and the stationary nonporous rider with spherical surface. The theoretical and experimental analyses have been carried out to investigate the effects of the curvature radius of spherical surface of the rider on the frictional characteristics and the electrical conductivity. The experimental analysis is conducted with a pin-on-disk friction tester to measure the frictional force and the contact voltage between the sliding contacts. The oil-film force and the frictional force between the rider and the rotating disk are also calculated by simultaneously solving the modified Reynolds equation and the Laplace equation derived from Darcy's law. The numerical results qualitatively agree with the experimental results. These results show that reduction in the curvature radius of spherical surface extends the operating conditions under the continuous metal contact to a higher value of the bearing characteristic number S defined by ηU_0L(B/L)/W ( η:oil viscosity, U_0:sliding speed, L:length of rider in direction of motion, B:width of rider, W:applied load), and it also decreases the frictional force at the maximum S at which the rider could contact with the disk surface. This phenomenon is expected since upstream lubricant oil dragged into the contact region tends to easily leak out in the direction perpendicular to the sliding due to the diverging zone formed between the disk and the rider with spherical surface, yielding a lower oil-film force and enhancing the metal contacts.

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The influence of the positioning error, the eccentricity or shape error, which is made during the milling process, at the planetary gear center or the internal gear of the star type planetary gear trains to the torsional resonance are discussed using the simulating program. The program was previously confirmed that it can sufficiently simulate the vibration occurrence speed of the rotational shaft and the vibration orbit of the floating sun gear. In the conclusion, the positioning of the gears make the change of the self-centering position of the floating sun gear and the shape of the movable area of the sun gear. But they are not the cause of the resonance, because the resonance does not occur without the forced torque. The eccentricity of the planetary gear can be the cause of the resonance when the rotation speed of the planetary gear becomes the natural frequency of the rotating shaft. But the eccentricity of the internal gear is not the cause of the resonance. The triangle shape error of the internal gear, which is measured in the experiment, also simulated. And it is made clear that the shape error can be the cause of the resonance. This can be considered that the transmission error can be made by the coincidence of the shape and the number of planetary gears.

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In a bolt tightening, it is well known that the cause of tightening error of the torque control method is a variation of the frictional coefficients of thread surfaces and bearing surfaces. It is considered that the variations of the frictional coefficients are caused by the lubricated conditions and so on in the bolt tightening However if the bolt has some configuration errors, the frictional coefficients might be varied by them. In this study, an influence of the squareness error of bolt bearing surface on the clamping force error has been investigated using a simulated experiment. The results showed that the squareness error of bearing surface causes the clamping force error.

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It is known by past researches on the loosening of a screw that rotation of loosen will arise if the radius direction vibration is given to a bolt head or the bearing surface of a nut. On the other hand, it is known that it is effective in ultrasonic vibration reducing apparent friction, and the method of performing screw tightening with little variation is also studied, it is performed by tightening with the ultrasonic vibration. In use of ultrasonic vibration, a stronger effect can be acquired by using resonance. In this research, the bolt head or the nut was fastened with axial ultrasonic vibration by vibration resonance, and it is investigated about the effect.

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The purpose of this study is to investigate the effect of peening on the fatigue life of steel rollers. First, steel rollers were treated by three types of peenings to ensure the same surface roughness of peened rollers. One is the cavitation peening (CP) used a cavitating jet in water with an injection pressure of 30 MPa, and the others are the fine particle peening (FPP) with a shot diameter of 0.1 mm and the normal shot peening (NSP) with a shot diameter of 0.3 mm. The surface hardness and the surface compressive residual stress of the steel rollers were increased by all the peenings In particular, they were most increased by the FPP While, the work-hardened depth due to the CP and the NSP was larger than that due to the FPP. As a result of the roller tests, the fatigue lives of the steel rollers were improved by all the peenings, and they were most improved by the NSP. Judging from the P<max>-N curves and the [A(σ_y/Hv)]_<max>-N curves, the improvement m fatigue lives due to the FPP depended heavily on the increase in surface hardness due to that, and the effects of the CP and the NSP on the rolling contact fatigue were equivalent under the same surface roughness and the same surface hardness.

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In order to predict the fatigue strength of a bolt, two hypotheses had been presented Ishibashi's hypothesis is concerning the relationship between the local stress at the thread root of a bolt and the nominal stress, and Yoshimoto's one is concerning the effect of the axial residual stress at the first thread root of a bolt. However, these have not yet been verified since the local stress and the residual stress which may exist locally around the thread root cannot be measured or estimated with sufficient accuracy. This study aims to clarify the relationship between the residual stress and the fatigue strength quantitatively. In this report, simple 3-D FE analysis was done to calculate the axial residual stress distribution by using the interim FE model through the thread rolling process of the leadless bolt specimen, and the fatigue tests were performed for the leadless bolt specimens thread rolled before heat treatment (SV) and thread rolled after heat treatment (SG). Calculated result shows that the axial compressive residual stress about 440 MPa level is generated at the thread root at ε_0 = 30 μm layer of SG leadless bolt specimen. On the other hand, the difference between the fatigue strengths of SG leadless bolt specimen and SV specimen in the fatigue tests can be explained by the Ishibashi's and Yoshimoto's hypotheses if the axial compressive residual stress of 1200 MPa exists at the thread root of the SG specimen. Considering the residual stress distributions for grooved rolled specimen of the same material simulated and measured by X-ray diffraction method, the elements are too coarse around the root of the leadless bolt specimen, and can be improved by re-modeling.

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Bolt/double nuts assemblies are used for preventing the self loosening when the clamp force is relatively low. In general, the fatigue load acting on the bolt increases in the bolted joint with low clamp force due to the separation at the contact plane. However, the effect of the locking force on the fatigue strength of the bolt has not yet been clarified. This study aims to evaluate the fatigue strength of a bolt in bolt/double nuts assemblies quantitatively. Fatigue tests were performed for bolt/double nuts assemblies by taking the locking nut height as a parameter. FE stress analysis was also performed to predict the fatigue strength using Ishibashi's and Yoshimoto's hypotheses concerning the relationship between the local stress and the fatigue strength of the material. The results show that the locking force has the effect to decrease the local mean stress of the fatigue loading on the first thread root of the bolt mating with the lower nut, and leads to the increase of the fatigue strength of the bolt expressed by the nominal stress.

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Most studies of bolted joint fatigue have been conducted for a bolted joint subjected to only axial vibration or only transverse vibration. However it is considered that the actual bolted joints are subjected to multi-axial vibration. Bolted joint fatigue under multi-axial vibration, axial vibration and transverse vibration, has been investigated in this study. In the experiments, the two types of vibrations were applied to the test bolt with same phase and with different phase. The result shows that the obvious difference in each experiment could not be observed We have to conduct the experiment applying the heavier cyclic axial load to the bolted joints.

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Bolt can bend and become loose while they are use. However, there has been very little research on the loosening that can occur under repetitive actions, particuiary concerning the early stage of repetition. In the present study, rotation bending looseness testing machine was manufactured and used to investigate loosening of M8 steel bolted test piece following a small number (abou 500) of rotation bending cycles. As a result, at rotation bending, the difference was observed in the tendency of looseness by the case where load is loaded on a clamped part and a bolted test piece. It was hard to produce a slide with big clamp force, and the loosening produced by rotation bending in the presence of a load acting on the clamped part is similar to the initial loosening phenomenon.

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Nowadays, various kinds of locking devices are widely used in bolted joints for anti-loosening purposes. The prevailing torque type nuts have been widely developed and used in bolted joints for preventing self-loosening and dropout from bolt. Thus, the standards on prevailing torque type nuts have been specified in JIS and ISO. In this paper, experiments were earned out to measure the tightening and prevailing torque of bolted joints with two types calking prevailing torque-type-nuts. As the result, the bolted joint using the calking biggest nut shows the good performance for preventing the loosening compared with the bolted joints using thread calking type of the nut of which the calking deformation is the biggest, moderate and smaller.

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In recent years, many assist devices have been developing to enable the users to walk by an electric control system. However, introducing an electric control system makes the price rise of the device. It is difficult for users to purchase an expensive device, even if it is easy to use. In order to spread an assist device in daily life, a development with a low price and simple device is expected. The purpose of this study is the design and the development of the simple device for assisting walking movement to reduce the load of the human leg. The assist device is designed by using a planar 6-link mechanism which transforms a rotational motion into an oscillating motion. By this method, it's expected that the device is widely spread to general household because of inexpensive and simple structure. In this research, a height of kicking backward is controlled to stabilize the posture when using the device. We evaluate this device by inclination of the device from the viewpoint of disability and necessary input torque to drive the device Based on these inspections, we consider power source. We investigate the mechanism to drive by the swing motion of user's arm.

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With aging, the number of cases of knee joint inflammation is increasing now. The general treatment for the knee joint inflammation is adding external force on the knee and correcting in a normal state by the knee orthosis. Daily walking is important for the knee joint from getting worse, but the restricting the knee joint prevents the walking, so the knee orthosis is required to have the function of the assistance of the walk. The purpose of this study is design and development of the knee orthosis which promotes daily walking movement and reduce a burden to the knee joint of the walk. The knee orthosis is designed by using a planar 6-link mechanism. It is the system which gives a leg region an oscillating motion using the rotation of metatarsophalangeal joint as the input. The experimental device is manufactured on a trial basis to measure the knee joint angular displacement. And the efficiency is evaluated by comparing these values of the angular displacements, the joint torque and the electromyogram among not using orthosis, using orthosis whose input is linear rotation and using orthosis whose input is rotation.

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ER(electro-rheological) gel is one of functional materials, which adhesive force increases when an electric field is impressed. In this study, an ER gel is equipped for the human body directly to realize effective rehabilitation or force display. The property of ER gel in such case is applied to a brake element ER gel is generally used in a plane However, ER gel is used at a curved form, when it is set up on the human body. The force property of ER gels on the curved surface is not known well. Therefore, we develop an experimental device for pre-study on force display, and measure the adhesive force using the device. Then, we confirm the usefulness of ER gel for force display.

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In this paper, we propose a new device for determining a direction of a gas source using thermal air currents generated by Peltier elements. The use of thermal convective flow is advantageous in gas sensing. For example, a gaseous chemical substance trailing along the floor can be collected toward a gas sensor placed at an elevated height using thermal flow because it tends to rise. In the proposed device, heat is transferred using Peltier elements from the center of the device to its left and right ends. Spatially separated ascending air currents are generated from the warmer parts of the device, which bring a gaseous chemical substance trailing along the floor toward the left and right gas sensors. At the same time, a descending air current is generated from the colder central part of the device. This air current works as an air curtain to expand the difference between the right and left gas sensor responses. Experimental results are presented to show the soundness of the device design.

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The authors constructed the load distribution theory that considers the deformation of the carnage and rail by using FEM. As a result, the analytical accuracy of Linear Motion Guide has improved greatly Next, the authors extended this theory, reduced the analytical cost, and constructed Linear Motion Ball Guide System load distribution theory that considers the deformation of table and base by using FEM. The authors experimented to verify this new theory. In this paper, the authors report on the result of comparing the experimental and theoretical.

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A new fuel economy Continuous Variable Transmission Fluid (CVT Fluid) has been developed with the aim of improving fuel economy by reducing fluid churning resistance and drag resistance. One feature of the fuel economy CVT Fluid is that it has high performance of shear stability and lubrication even though it has reduced viscosity. That was achieved by innovatively blending the base oil and viscosity index improver. This article describes the characteristics of a new CVT Fluid.

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In this study, effective use of exhaust heat as one of the way saving energy of vessels is described. Recent years, the depletion of fossil fuels, air pollution by exhaust gas has become a serious problem. Therefore, the technologies about fuel saving and effective use of energy are required Vessels also use fossil fuel as an energy source. Large vessels generate steam in the boiler. This steam is used for heating and hot water supply in the vessel. But surplus low-pressure steam is discarded. If it is possible to generate electric power using the surplus low-pressure steam, that can contribute to energy saving of vessels. Therefore, prototype steam engine for generation using low-pressure steam was developed. This new steam engine is use the grooved cam as a motion conversion mechanism. First, prototype steam engine is introduced for the principle and structure Secondly, this steam engine is introduced for the configuration and design. Next, this engine is tested by low-pressure compressed-air and saturated steam. Finally, test result of the prototype steam engine is reported on this paper.

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A novel microstepping linear mechanism is designed for aiming at high-speed and high-resolution positioning. The mechanism employs two electromagnets for clumping the rail, and one electromagnet for longitudinal actuation of the mechanism Use of the electromagnet enables to high-speed feed rate and use of inexpensive low-voltage amplifiers. Moreover, toggle mechanisms are used for reducing the actuator's displacement and enlarging the actuator's force. Because the relation between the input and output displacements of the toggle mechanism is non-linear, the microstepper achieves both high-speed and high-resolution positioning as necessary. This paper describes experimental mechanisms equipped with two types of actuators and shows their experimental result. It was demonstrated that these mechanisms had 0.57 mm/s and 1.0 mm/s maximum speeds and the positioning resolution less than 0.1 μm.

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There have been a number of issues concerning the sliding characteristics of oil-impregnated sintered bearings caused at the temperature below freezing. However, the relationship between bearing design parameters and tribological characteristics below freezing has not been clarified yet. In this study, we experimentally investigated the coefficient of friction and separation degree between the oil-impregnated sintered bearing and the journal operating at below-freezing temperature. As a result, the following factors were found as the influence of the ambient temperature to the friction characteristics of the oil impregnated sintered bearings. One is that, in below freezing conditions, the friction coefficient μ increases along with the increase of Sommerfeld number (S). In addition, if the value of S is the same (1.e. the viscosity is the same), the coefficient becomes smaller as the ambient temperature lowers. The other is that the friction characteristics in below freezing conditions are influenced by the increase of the lubricating oil viscosity due to the temperature decrease and the permeability of the bearing. Depending on a balance between them, the ambient temperature has different effects on the ju-S curve.

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In this study, stress distributions in a con-rod of an engine are studied using a 3 Dimensional Computer Aided Design Software, 3D-CAD CATIA. A structural CAD model of a con-rod is made with the CATIA. A FEM structural analysis is performed in the CATIA for making a compliance matrix which expresses relation between bearing deformation and oil film pressure distribution and is used in an Elastohydrodynamic Lubrication, EHL, analysis. Pressure distributions and deformation on a con-rod bearing is calculated with the EHL analysis under a dynamic load of the engine. The pressure distributions are used for calculation of nodal forces on the bearing surface which are used in the structural analysis of the con-rod. Finally, stress distributions in the con-rod under the engine operation can be obtained.

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The occurrence conditions of electrical pitting in ball bearing for applying direct current have been made known. However, the report on the electrical pitting in applying alternative current is very few. In this research, experiments on electrical pitting of ball bearing in applying alternative current. In consequence, the travelling mark on the surface of raceway track was thin and the deterioration was minor. Therefore, the authors considered the concernment between the discharging energy and the deterioration very likely.

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Advances in various areas of precision mechanics such as semi-conductor exposure apparatus, MEMS/NEMS, nano-imprint lithography devices and other nano-technology applications, have required ultraprecise positioning techniques with nanometer-scale accuracy to be developed. Our laboratory has developed a 'pneumatic servo bearing actuator (PSBA)' as a novel actuator that uses pneumatic servo technology for ultraprecise positioning. The actuator mainly consists of an aerostatic thrust bearing and a pneumatic servo valve. In the actuator, the pressurized air controlled by the servo valve moves an actuated spool supported by the aerostatic bearing ultraprecisely. However, the stroke of developed actuator was short, less than several dozen of micrometer, because the bearing clearance directly corresponded to the displacement of actuated spool. To expand the actuator stroke, the PSBA with multiple thrust bearing pads arranged in laminate structure was newly proposed and developed. The experiment using the developed actuator with thirty bearing pads showed that the actuator stiffness was kept constant even in long stroke up to 150 um and the step response and settling time improved as compared with those of the actuator with a single bearing pad. In addition, we confirmed that the minimum resolution of the actuator was less than 10 nm even without feedback controls, which was enough to meet the demands of current ultraprecise positioning technology.

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Oiliness additives used under boundary lubrication forms adsorption layer on a surface of metal, and reduce friction and wear by preventing a severe contact between two surfaces. This study investigated chemical characteristic of the adsorption layer by means of Fourier transform infrared spectroscopy (FT-IR) and its effect on the tribological properties by using a ball-on-disk friction tester. The sample surface we used for the study was copper-coated silicon wafer prepared by physical vapor deposition. The oiliness additive and the base oil were palmitic acid and poly-alpha-olefine (PAO) respectively, and we mixed the acid into PAO with various concentrations before the test. Experimental results showed that all coefficients of friction with the acid greatly reduced, 60% down at a maximum, as compared with those without the acid. Then, the absorbance peak of polar group (COO) and non-polar hydrocarbon group (CH_2), and (CH_3) were detected by FT-IR for the surfaces under the base oil containing the acid as a proof of the formation of adsorption layer. When the oil temperature was raised up to 50°C, the coefficient of friction increased up to the same level as those without acid, and then the absorbance peaks from polar functional groups were not detected, meaning that the adsorption layer began to be desorbed over 50°C.

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In general, not only an actual driving test using an automobile but also a laboratory test using a small rubber specimen are performed to study the friction and wear properties of tires. Laboratory test can be carried out easier than actual driving test. On the other hand, it is said that the result of the experiment in laboratory often differs from that of actual driving test. The differences in the experimental conditions such as contact areas, the contact shape, the mating surface, and so on are believed to cause the differences in the results. In this study, rubber specimens with various contact areas were rubbed against mating abrasive paper under same contact pressure for the basic study of the linkage between the laboratory test and the actual driving test. As a result, the friction and wear properties of rubber having different contact area differed, though the same kind of rubber was rubbed under the same contact pressure. Considering the ratio of contact area to thickness of the rubber specimen, the rubber with identical ratio showed approximately the same wear properties when the ratio is high. It seems that the specimen thickness affects the friction and wear properties of rubber.

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In recent years, silica filled styrene butadiene rubber have been used in tread rubber of low rolling resistance tires for automobile. The purpose of this study is to clarify the wear property of silica filled rubber. The experiment was carried out using pin-on-disk tribometer, six types of styrene butadiene rubber blended with butadiene rubber with different contents of silica and carbon black filler were used as rubber specimens and the specimen was rubbed against metal gauze in silicone oil. As a result, it was founded that the more specimen contains silica filler, the more smaller specific wear rate K and coefficient of friction u. The worn surface of specimen was observed by scanning electron microscope (SEM), and all specimens have abrasion pattern. Fatigue test was also conducted and surface area in the vicinity of a crack was observed by an atomic force microscope.

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In the current work a numerical elastohydrodynamic simulation is conducted for a one-dimensional step bearing. The effect of elastic deformation of the bounding surfaces and piezoviscous effect were simultaneously solved. The present numerical results indicate that the elastic deformation less than 200 nm was responsible for the film formation when the film thickness was small. The small elastic deformation changed the film shape over the contact area with decreasing the film thickness. A divergent film shape in the step zone appeared while a convergent film shape was produced because of the elastic deformation. The step film shape was still remained, which played an important role in the pressure generation. Such a film shape produced the delay in pressure generation in the step zone, i.e. the starting point of the pressure generation was located around the centre of the contact area. The delay in pressure generation resulted in significant reduction in load capacity.

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The present study describes erosive wear of hardened chromium alloy steel against fine sphere particle. A sand blast apparatus consisted from double walled nozzle and rubber balls enclosed tank used for the experiment. Alumina beads of 50 um in diameter were impacted to the mirror finished specimen surface at various treatment times. Results showed that the eroded surface has hardened by the particle impacts at initial stage of the experiment. The increase of the erosive wear loss corresponded to that of the hardness. Consequently, it was estimated that the erosive wear of the alloy steel against the fine particle impact occurred in the work hardened region.

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Running-in process is important for sliding parts of machines, because it has an influence on friction and wear properties of the sliding materials. If the running-in process is not well done, serious troubles such as seizure and abnormal wear may occur in the machines. DLC (Diamond-like carbon) films are used in various fields as an excellent tribo-material because of their low friction coefficient and their high wear resistance. However, the running-in behavior of DLC films is not clarified quantitatively. In the present work, we investigated an influence of loading rate to running-in process of DLC films from the stand point of friction coefficient and worn surface. As a result, in case of combination DLC films and FC230, friction coefficient increased with increasing loading rate. Also there was good correlation between protruding peak height and friction coefficient.

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