• Tribology and Lubricants
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• 제16권4호
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• pp.259-265
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• 2000

Pump which is the fundamental device in the hydraulic system affects on overall system performance to a great deal. Such problems as leakage and solid friction loss become important in field applications, especially for the case of operation under high pressure and at high speed. So the research on this kind of subjects is necessary to improve the performance of hydraulic devices. A high pressure radial piston pump is analyzed here, which has a stationary cylinder block. It pumps hydraulic fluid by letting camring push a piston in a cylinder. Fluid leaks between the piston and cylinder so that it deteriorates the pump efficiency. Furthermore, the piston happens to touch the cylinder wall to increase the friction loss and wear. In this research, by means of FDA, volumetric, mechanical and overall efficiencies are observed by varying several design parameters and operation conditions. Design values or their trends are presented to improve these effciencies.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.66.1-66
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• 2002

Today it becomes a serious problem to exhaustion of a fossil fuel and air pollution by exhaust gases from road vehicles for environment preservation. To solve this problem, the developments of a hybrid vehicle have been processed for the purpose of reducing pollution and energy-savings. By the way, flywheel hybrid vehicle using variable pump/motor was proposed as one feasible hybrid system in place of hybrid vehicle system by the conventional storage battery. The proposed flywheel hybrid vehicle is composed of an accumulator or a flywheel as the energy generation and storage source and three variable hydraulic pump/motor as the energy transfer device. Flywheel has the characteristic of high...

• 연구논문집
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• 통권32호
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• pp.15-22
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• 2002

In offset or intaglio printing machine, it's operated with combination of blanket cylinder and impression cylinder. The blanket cylinder has some number of grooves to attach the blanket on surface. In case of operating the printing machine, it has generate mechanical impact noise when the two cylinders encounter with the grooves. So, in this study, we developed a printing pressure control algorithm with hydraulic servo control system. We also proposed simulation model of experimental device to analysis the throw on force response of hydraulic servo actuator. Finally, we have reduced the mechanical impact noise and improved printing quality with a groove detecting signal and PI control of hydraulic servo actuator.

• 수산해양기술연구
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• 제34권2호
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• pp.231-237
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• 1998

Generally, the three position solenoid valve has veen used for the hydraulic steering gear on account of it’s low cost, simplicity in device, etc. But, there is some off-set because of dead-zone which exists in on-off valves. In this paper, we proposed a combined controller which was added an integral controller to an only on-off one in hydraulic steering gear control system used low speed three position solenoid valve. Experimental results show that the off-set is removed, and the number of valve switching is reduced considerable. The validity of proposed method comparing with an only on-off control was proved by the response experiments.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 춘계학술대회 논문집
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• pp.87-92
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• 1999

This paper was undertaken to do morphological analysis of wear particles for sliding members hydraulic rotary actuator. The lubricating wear test was performed under different experimental conditions using the wear test device and wear specimens of the pin on disk type was rubbed in paraffinic base oil by three kinds of lubricating materials, varying applied load, sliding distance. The four-shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) are used for morphological analysis of wear particles. The results showed that the four shape parameters of wear particles depend on a kind of the lubricating materials. It was capable of presuming wear volume for three kinds of materials on driving time.

• 한국생산제조학회지
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• 제9권6호
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• pp.127-132
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• 2000

Morphological analysis of wear particles is one of useful methods for machine condition monitoring because it is well reflected in machine driving state. This paper was undertaken to apply to the condition monitoring of hydraulic piston motor. The lubricating wear test was performed under different experimental conditions using the wear test device and wear specimens of the pin on disk type was rubbed in paraffinic base oil by three kinds of lubricating materials, varying applied load, sliding distance. The four shape parameters(50% volumetric diameter, aspect, roundness and reflectivity) are used for morphological analysis of wear particles. The results showed that the four shape parameters of wear particles depend on a kind of the lubricating materials. It was capable of calculating presumed wear volume for three kinds of materials on driving time to foresee as damage condition of lubricating materials.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.181-186
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• 2002

Lately, as going on increasing in the demand of high power density(power/weight), it is necessary for hydraulic axial piston pump/motor to operate more high pressure and speed. But in these condition, there are some trouble like as friction loss. To reduce this friction loss, hydrostatic bearing is used far axial piston pump/motor frequently. In general, it is difficult to measure accurate friction torque of spherical hydrostatic bearing in the use of the existing devices. So, we have developed the measurement device using the reaction torque sensor to obtain the pure friction torque, fitted in the casing. In this report, we intend to make an introduction about this measurement device for friction torque of the spherical wear part and clarify the effect of friction characteristics on supply pressure and rotational speed with three types of pocket size by using this measurement device.

• 소음진동
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• 제7권5호
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• pp.765-772
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• 1997

This paper presents the swing motion analysis of the container crane headblock with the passive control device using hydraulic motors and anti-swing ropes. The device hauls at the headblock to opposite direction of its swing motion using the tension difference between anti-swing ropes connected to the headblock. To consider this control mechanism, the headblock is modelled as the rigid bar suspended by two hoist ropes at the overhead trolley and its non-linear equation of motion is derived using Lagrange's equation. Some numerical experiments using the equation are carried out to investigate the swing motion characteristics of the headblock under the variation of geometric relation among the cargo handling components and to evaluate the performance of the anti-swing device.

• 한국자동차공학회논문집
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• 제9권2호
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• pp.143-151
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• 2001

In the recent day, fatigue life prediction techniques play a major role in the design of components in the ground vehicle industry. Full scale durability testing in the laboratory is an essential of any fatigue life evaluation of components or structure of the automotive vehicle. Component testing is particularly important in todey's highly competitive industries where the design to reduce weight and production costs must be balanced with the necessity to avoid expensive service failure. Generally, Multi-axis durability testing device is used to carry out the fatigue test. In this paper, The operation software for simultaneously driving Multi-axis vibration testing device is developed and the input and output data are displayed in windows of PC controller with real time. Moteover the characteristics of the displacement and the load of Multi-axis actuators are calibrated separately.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2609-2614
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• 2007

Shell & Tube type Oil Cooler is widely used for hydraulic presses, die casting machines, generation equipments, machine tools and construction heavy machinery. Temperature of oil in the hydraulic system changes viscosity and thickness of oil film. They have a bad effect to performance and lubrication of hydraulic machinery, so it is important to know exactly the heat exchanging efficiency of oil cooler for controlling oil temperature. But most Korean manufacturers do not have test equipment for oil cooler, so they cannot carry out the efficiency test of oil cooler and it is impossible to verify its performance. This paper includes information of construction of necessary utilities for oil cooler test and design and manufacture of test equipment. One can select the optimum product by obtaining performance data through tests of various kinds of oil coolers. And also the paper developed a program which can be easily used for design of 2D and 3D drawings of oil cooler.