The programmed control variable loading unit was constructed. This unit consists of hydraulic power unit, optical reader by photo-transistor, amplifier and prony brake for loading. The process of signal flow is as follows: The input signal is supplied by the punched tape and amplified. Then the relay acted and drives the directional valve. The change of the oil flow drives the hydraulic cylinder back and forth. The displacement of the hydraulic cylnder is related to the action of loading or unloading to the Prony brake. This unit was used for the hundred hours engine test. The effects of the STP additives will be discussed in the following report. Through the development of this unit, the followings are summarized: 1. The programmed control variable loading unit worked satisfactorily as the loading unit for engine test. 2. The outputs such as torque of axle and the displacement of the hydraulic cylinder were predicted through the punched tape signal input. The graphical integration method and the cycle diagram were applied to predict the output signals and the predicted output signals were compared with the ones obtained from the experiments. 3. The maximum frequency response of this unit is due to the ones of the directional valve and the relay, therefore it should be less than two or theree hertz. 4. For the simulation of the variable loading with high frequency, the electrical clutching device will be more effective instead of the hydraulic prony brake. 5. Further inspection how the real load variation in the field operation should be transfered onto the punched tape should be done.
We report the results of experiments on the static characteristics of engine output power constant control system and discuss them in this paper. This control system consists of the closed circuit PV-MF hydrostatic transmission system and the torque constant type servo-control regulator being its control device. If pump input speed is constant, this system has such a function as keeps constantly the pump input power, namely, engine output power in spite of great and small sizes of the disturbance of torque. For further details the reader should refer to previous report (I). A summary of the results is shown below. 1) It became evident that pump input torque had always a constant value regardless of great and small sizes of load pressure. But, it was difficult to find a certain relation between pump input torque and its speed. These results agreed approximately with the characteristics shown in design diagram. Thus, it have been proved that the pump output pressure detecting actuator acted successfully, but the pump input speed detecting one must be improved on a few points. (See. Fig. 3 (a)) 2) Overall efficiency of the variable-displacement type axial-plunger pump was about 60-85% in the region of normal load, and the efficiency of the fixed-displacement type axial-plunger motor was more than 90% in the same region. Judging from these effects, it was evident that efficiency performance was affected remarkably by the displacement of pump or motor. (See. Fig. 3 (d), (e), (f) and Fig. 5 (d), (e)) 3) In order to obtain quantitatively the optimum quantity for tractor operation about the control system used, we tried to represent the combination diagram of the engine governor setting and the pump stroke setting for pump output flow and motor differential pressure. As is evident from the design principle of this control system, it is shown that these combinations are the optimum setting values which give the best mechanical performances to engine and hydraulic system. This diagram is useful to simplify and speed up the tractor operations which were done by intuition and experiences up to this time. (See. Fig. 7) 4) In order to estimate effects of this control system, we compared the differences in following performances between the two cases of having the control action or not, i. e., transmission efficiency in the case of hydraulic system and power utilization rate (P. U. R) and specific fuel consumption (S. F. C) in the case of engine system. These experimental results proved that this control system was always operated under the optimum condition from the point of mechanical and economical performance, and that satisfied sufficiently the initial control purpose. (See. Fig. 9, Fig. 10 and Fig. 11)
In this paper, the theory based on the approximation that the contact pressure distribution area of the drive wheel consists of two zones, the compressing zone and the bulldozing one, was experimentally confirmed on the actual soil, using the soil bin testing facility. The following items were discussed or estimated: a. Relation between the pulling force and the slippage b. Thrust force, pulling force, running resistance and their relations. c. Forces acting on the driving wheel at running. Theoretical approach was quite valid compared with the experimental results. As the results of the experiments, the followings were found: 1) Some of the contact pressure distribution area diagrams obtained in the experiments showed two zones, especially at higher slippage more than 40%. 2) Relation between the thrust force and the pulling force was a linear. Thrust force was estimated by the equation developed in the measured values of the pulling force and the torque of the wheel axle. 3) Measured and estimated forces and other unknown factors showed quite reasonable results. For further study, an efficient transformation of the thrust force produced at the wheel-soil interface should be considered, and the optimal shape and dimension of the running device must be found.
In this paper, the slip sinkage phenomenon of a tractor drive wheel at 100% slip condition under the pulling load was discussed, especially on the slip sinkage transient curve and the torque of the drive wheel axle. In estimating the torque of the drive wheel axle, two kinds of method were applied. 1) The use of the relation between the mean contact pressure and sinkage, derived from the geometrical relation. 2) Application of the quadratic curve to the radial contact pressure measured with a pressure sensing beam on the wheel periphery. Shear force at the interface between the tread and the soil was estimated by multiplying the radial contact pressure by the frictional coefficient at the interface. The torque of the wheel axle was calculated by integrating the shear forces along the contact length. On the other hand, the relations between the rotational angle of the wheel axle and the sinkage were obtained from the tests under the constrained condition of the horizontal motion of the wheel. Tests were held for three kinds of soil hardness 0.2, 0.4 and 0.6kg/cm2 respectively. Those relations were applied to the model of the drive wheel shown in Fig. 2, and the results of the theory and the experiments on the sinkage were compared. It was found that the geometrical mean contact pressure in radial direction was more efficiently available to estimate the wheel axle torque. The estimated values using a geometrical mean contact pressure was quitely coincident with the experimental ones.
In order to investigate the dynamic side-overturning of tractor, the authors analyzed the problem mathematically and compared with the experimental results. In this paper, a tractor was idealized into a model of spring-mass system with two degrees of freedom, and the pneumatic tire was assumed as the parallel combination of linear spring and viscous damper. (1) It was supposed that a tractor overturned when its uphill wheel ran up a certain obstacle (sine curve, triangle) on a slope. The critical running speed which brought the tractor-overturning on several slopes was calculated under the above mentioned states. (2) When the upward velocity of the uphill wheel on an obstacle was larger than the critical upward velocity calculated by the equation (20), the tractor overturned sideways. (3) The calculated values indicated that the tractor was apt to overturn with the increase of the height of obstacle and the running speed. It became more difficult to overturn for a tractor as the spring rate decreased, and the tractor didnot overturn when the spring rate and the height of obstacle were smaller than the limited value, respectively. (4) On the model tractor, the experimental results with the triangle obstacle were nearly equal to the calculated values in the assuming that the tractor bounds up at the top of the obstacle.
Dynamic and geometrical similarities were tested in a fine dry sand using three kinds of model shoes with similar configuration (Tab. 2). Each model shoe consisted of three plates combined in such a state as shown in Fig. 1 to investigate the effects of space e. Horizontal draft and slip sinkage of model shoes were determined as the dependent variables and the pertinent variables of them were selected (Tab. 1). Design or operating conditions were obtained by dimensional analysis. Experiments were done under the three levels of v, p and e (Tab. 3) in the test apparatus shown in Fig. 2. In the test apparatus, the model shoes were drawn always in a horizontal posture. Draft and sinkage were measured by means of a strain gage type force transducer and a differential transformer, and forward displacement of model shoe was also recorded. Influences of independent variables to draft or sinkage of model shoes and similarity at four categories of IIs, were investigated mainly by the method of the analysis of variance. —ANOVA—. The results obtained were as follows. 1. Effects of v to D or Z were negligible within the range of velocity designed in this test. 2. The outstanding effects of p to D and of e to Z were recognized. 3. As the ineffectiveness of v was cleared, similarity was tested supposing that the same experiments were carried out three times in three levels of IIp and IIe. Each combination of IIp was considered to be a specific model shoe-sand system, and then, ANOVA was adapted to each system. 3.1 Dynamic similarity In most of the combinations of IIp and IIe, the existence of dynamic similarity was recognized (Tab. 7). However, beyond IIs=1.5, there were some cases that the similarity did not come into existence. It seems that the dissimilarity was brought from some differences of an initial condition of each shoe which were enlarged with its forward displacement 3.2 Geometrical similarity Geometrical similarity was recognized when IIe was zero. In other words, the gradient of sinkage plane of model shoe was similar when space was not given (Tab. 11). 4. IID or IIZ versus IIp and IIe Significance was cleared through the inspection of ANOVA (Tab. 8) that IID or IIZ varied with IIp and IIe, but interactions were not seen. Their relationships are presented as a plane in Fig. 4 and 5.
Analyzing the kneading effect on the shearing characteristics of artificial soils under the same kneading conditions as the report No. 2 of this study series, following results were found. 1) Representing the shear stress-displacement curve by an equation proposed by Kacigin and Guskov, the value of the displacement at peak stress Kτ changed slightly with the kneading time. 2) The kneading effect on the shear strength was proved to be significant through an analysis of variance. It was also shown, however, that the shear strengths of Soil A and B approached to constant values after more than 10 minutes kneading time. 3) The kneading effect on the soil values was not apparent due to minority of data. It was shown, however, that the soil values varied at the initial stage of kneading time. 4) Adopting Meyerhof Theory for the ultimate bearing capacity of long footings in order to consider the kneading effect on the penetrating resistance of a plate theoretically in relation to the kneading time effect on the soil values, it was derived that the variation trend of plate penetrating resistance due to kneading time was obtained through the theory. Theoretical values did not coincide with the measured values, and the problem of the measuring accuracy of soil values remained unsolved.
Wire type sugarcane stripping machine shown in Fig. 1 was experimented to improve the useful life of stripping wire with changing single wire diameter, fixing method of wire and rotating speed of stripping drum. To evaluate the effect of single wire diameter, rotating speed of stripping drum and stripping pitch on the rate of trash, broken mature stalks and broken immature tops, field tests were done on sugarcane variety Nco 310, The results obtained are as follows. (1) The useful life of wire was affected mainly by the fixing method of wire, rotating speed and the lap. The fixing method shown in Fig. 2 (b) revealed longer life of wire than Fig. 2 (a). (2) We can use single wire 1.04mm in diameter without bruising and shredding of cane. (3) As the rotating speed of stripping drum increased the rate of broken immature tops and broken mature stalks increased, but the rate of trash and the useful life of wire decreased. (4) An increase in stripping pitch did not affect the rate of broken mature stalks, but decreased the rate of trash. (5) In this machine, it was not enough to separate trash detached from the stalks. (6) The wire rapes should be replaced after stripping about 35 tons of cane, and the useful life of wire was about from sixty to seventy hours.
This investigation was carried out to find out the effect of temporary storage on the qualities of rough rice which was dried to 15% moisture content after temporary storage. Half-dried rough rice of different moisture contents (20%, 18%, 17% and 15%) was obtained from the rough rice of different initial moisture contents (23.0%, 19.7%) by two types of commercial dryers (Tempering dryer and Continuous dryer), and was stored in 18 plastic bins. On 99th day after starting of temporary storage, a half portion quantity of samples was dried to 15% moisture content, and on the 165th day the remaining half portion of samples was dried to same moisture content. Both samples finished in this way were stored under the laboratory condititions for storage tests. Storage stabilty was evaluated by measurement of temperature, moisture content, germination viability, mold population and fat acidity. The temperature of initial rough rice was 16-4°C during temporary storage and was 8-11°C on 99-165th beginning of storage tests. Then it started to rise slowly with rising of room temperature and reached about 23°C at the end of storage tests. There was about 1% decrease in moisture content for all samples over the storage period. The germination viability of rough rices (below 18% moisture content) maintained over 80% T. Z. value, and percentage viability of stored samples for short period was higher than that of stored samples for long period. The mold contamination of husked rice occured during temporary storage but molds populations did not increase in the half-dried rough rice dried to 15% moisture content. Some of the mold contaminations were lost mechanically during the drying proess. Changes of fat acidity were govered by moisture content of samples in temporary storage. Once the increasing tendency of fat acidity appeared, they were unable to be stopped increasing, even if samples were dried to 15% moisture content. Conversely some examples showed that fat acidity of samples increased after being dried to 15% moisture content. In other case, changes of fat acidity was influensed by the initial moisture content. Hereafter the authors intend to investigate the relation of the drying time of half-dried rough rice, the drying conditions and the initial moisture content of half-dried rough rice on the qualities of stored rice.
Modern agriculture has brought about the harvesting, handling and processing of agricultural products by various specific machines or devices. Despite of the fact that the design of these are associated with the physical characteristics such as shape, size, volume, density and mechanical properties, little is known about the basic physical characteristics and properties of agricultural products. This experiment was run to obtain the data of the shape, density and other physical properties on cucumber, KURUME-H, harvested in greenhouse. The results were as follows: 1) Shape, and some physical properties; the stem-end side (portion I in Fig. 1) is bigger than the middle and apex side (portion II and III). The ratio of the mean diameter to the length is 0.132, and the means of the specific weight and the moisture content are 0.98 gram per cucic centimeter and 95.3 percent W. B., respectively. 2) Compression test (crosshead speed; 10mm/min.); the overall toughness is about 1.37kg-cm/cm3 (c. v. 28.9%), and the mean of longitudinal compressive elasticity is 23.0kg/cm2 (c. v. 4.3%). Also the difference is found between stem-end and apex portion. The compressive crushed stress and elasticity of homogeneous flesh, removed the seed portion and skin, are about 11kg/cm2 and 29kg/cm2, respectively. 3) Tensile test (c. s.; 10mm/min.); the break down stress of tension on homogeneous flesh is about a fourth of the rupture stress in compressive test. Also, tensile elasticity is about a half or the less of compressive elasticity. 4) Penetrating test (c. s.; 10mm/min, ); the results, using flat die plungers of 4mm and 2mm dia., show that difference by the portion and the freshness are in the penetrating energy and the lateral elasticity by the die. 5) Creep-recovery test (c. s.; 10mm/mn.); plate quasistatic load-deformation and the deformamation-recovery ratio, have high correlations, respectively. Under the test conditions, critical creep load is about 400 gram per unit length (cm), and the critical strain is about 0.09 in lateral, diameter (cm/cm) of the cucumber, KURUME-H..
The ultrasonic measurements of the physical properties of soybeans were found to be an effective means to determine dynamic moduli of elasticity at various moisture contents. The followings can be derived from this experiments. 1. Ultrasonic waves were effectively used for the nondestructive determination of dynamic moduli of elasticity and dynamic Poisson's ratio. 2 The propagation velocity of ultrasonic wave in a soybean increased with the decrease of the moisture contents. This relationship can be used for the continuous and non-destructive detecting of soybean moisture under storage or processing. 3. The dynamic moduli of elasticity of soybeans decreased with the inrease of moisture contents. The effects of moisture content upon the shear modulus and Poisson's ratio were not clear in this experiment. 4. Further research will be suggested to find the effects of moisture content upon the damping characteristics of the ultrasonic wave passing through a soybean. 5. The propagation characteristics of ultrasonic wave in the soybeans in bulk should be studied in the future.