• Tribology and Lubricants
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• v.12 no.3
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• pp.100-106
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• 1996

Gerotor pumps and motors are widely used in lubrication and hydraulic actuator systems. Compared with internal gear pumps and motors, they have many advantages. However, the gerotor profiles have not been suff'lciently analyzed theoretically. Therefore, it is very difficult for designer to decide the specifications of the gemtor profiles, and calculation of flow rate and minimum distance of clearance in the contact point of inner and outer rotor is not yet confirmed. In this paper, when we design inner and outer rotor concurently, we have analyzed the gerotor profiles and displayed the calculated results such as flow rate, minimum distance between inner and outer rotor and gerotor profiles.

• Journal of Drive and Control
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• v.14 no.1
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• pp.29-34
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• 2017

This study analyzed a life test method for a power take-off (PTO) gearbox. An engine transfers mechanical power (rotation and torque) to a hydraulic pump through a PTO Gearbox with one input shaft and three output shafts. PTO gear box durability under high loads over long time periods was tested using dynamometers. In order to reflect the rated operating conditions, power must be distributed to each output shaft, and experiments were conducted under various conditions to verify the characteristics of the distributed power. An accelerated life test was designed using speed and torque as acceleration factors. Also, efficiency tests were conducted under various load conditions. Also, a lubrication oil composition analysis was performed to analyze gearbox wear status.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.2
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• pp.13-22
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• 1997

Power flow characteristics of a hydro-mechanical transmission system(HMT) are investigated for tracked vehicle in steering. A HMT consisting of two hydrostatic pump motors(HST), several planetary gear trains and steer differential gear is considered. In order to obtain the direction and magnitude of the power flow of the HMT, network theory for the general power transmission is used. Network model for the HMT in steering is developed, which consists of shafts, nodes and transmission elements such as clutch, gear, etc. Power flow analysis procedure consists of two stages : (1) traction force analysis in steering, (2) power flow analysis in HMT. Torque and speed of every transmission element of the HMT is determined from the network analysis. Also, efficiency, mechanical and hydraulic power loss including HST, are obtained. In addition, the regenerative power flow resulting from steering can be studied in graphic display. The power flow analysis program(PCSTEER) developed in this work can be used as a useful design tool for the tracked vehicle with HMT.

• Journal of Biosystems Engineering
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• v.36 no.4
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• pp.243-251
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• 2011

Purpose of this study was to analyze power requirement of an agricultural tractor for baler operation. First, a power measurement system was developed and installed in a 75 kW agricultural tractor. Strain-gages with a telemetry system were used to measure torques of transmission and PTO input shafts. An engine tachometer was used to measure rotational speed of transmission and PTO input shafts. The measurement system also included pressure sensors to measure pressure of hydraulic pumps, an I/O interface to acquire the sensor signals, and an embedded system to determine power requirements. Second, field experiments were conducted at two PTO speed levels, and proportion of utilization ratio of rated engine power and power consumption of major parts (transmission input shaft, PTO input shaft, main hydraulic pump, and auxiliary hydraulic pump) were analyzed. Results of usage proportion of engine power for PTO speed level 1 and 2 were 4.1 and 2.2%, 31.5 and 16.3%, 49.6 and 59.7%, 14.4 and 20.8%, and 0.4 and 1.0%, respectively, for ratio of measured engine power to rated engine power of less than 25%, 25 ~ 50%, 50 ~ 75%, 75 ~ 100%, and greater than 100%. The results showed that the usage proportion increased in the range with the ratio of power requirement to rated engine power of over than 50% when the PTO gear was shifted from P1 to P2. Averaged engine power requirement for baling operation, tying and discharging operation, and total operation were 43.3, 37.3, and 42.0 kW and 49.0, 37.0, and 47.4 kW, respectively, for PTO speed level 1 and 2. Paired t-test showed significant difference in power consumption of engine, transmission input shaft, and PTO input shaft for different PTO speed levels. Therefore, the power consumption of engine for baler operation increased when the PTO gear was shifted from P1 to P2. It was indicated that the power requirement of tractor was affected by the PTO rotational speed for baler operation.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.845-855
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• 2022

The purpose of this study is to develop a self-propelled underground crop harvester and its performance was evaluated by measuring the load during actual potato harvesting operations. This study was conducted at a constant working speed of 1 km·h^-1. A load measurement system was installed to measure the actual load and the required working power was analyzed. A hydraulic pressure sensor was also installed to measure the hydraulic pressure. The required hydraulic power was calculated using the hydraulic pressure and flow rate. The results showed that the engine speed, torque, and power during harvesting operation were in the range of 845 - 1,423 rpm, 95 - 228 Nm, and 9 - 31 kW, respectively. Traction power, excluding the hydraulic pump of the tractor and power take-off (PTO) output, was in the range of 9 - 28 kW, and it was confirmed that it occupies a ratio of 16.2 to 50% of the engine rated output. The engine can supply the minimum required traction power to move the vehicle. This means that the engine used in this study could be down-sized to be suitable for an underground crop harvester. In this study, the gear stages of the tractor were not considered. This research thus shows the possibility of developing a self-propelled underground crop harvester.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.3
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• pp.207-216
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• 2016

A gerotor is suitable for miniature manufacturing because it has high discharge per 1 cycle and a simple structure, while also being widely used for lubrication oil of engines and as a hydraulic source of automatic transmission. In the automobile industry, improvements in fuel efficiency and noise reduction have recently come to the fore. It has also been necessary to continuously improve the flow rate and noise of internal gear pumps for better fuel efficiency through optimal gerotor and port shape design. In this study, to develop an optimal gerotor with a new lobe shape, 2-ellipses-combined, the equation of the lobe shape was derived, and CFD analysis results were compared for 2-ellipses with those of the previous gerotors (3-ellipses and ellipse1-involuteellipse2). A performance test for the oil pump with the optimal rotor (2-ellipses) was carried out and showed good agreement with the results obtained from CFD analysis.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.11
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• pp.927-935
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• 2016

A gerotor is suitable for miniature manufacturing because it has a high discharge per cycle and a simple structure, while also being widely used as lubrication oil of engines and the hydraulic source of automatic transmission. In the automobile industry, it has been necessary to continuously improve the flow rate and noise of internal gear pumps for better fuel efficiency through optimal gerotor design. In this study, to obtain an optimal gerotor with an ellipse-elliptical involute-ellipse combined lobe shape, an automatic program was developed for calculating performance parameters and drawing a gerotor profile. An oil pump was assembled with the optimal gerotor together with the port used at the actual field and CFD analysis was performed on this assembly using Ansys-CFX. A performance test for the oil pump was carried out and showed good agreement with the results obtained from the theoretical analysis and the CFD analysis.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.6
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• pp.797-805
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• 2019

An important problem of offshore plant process piping is equipment accidents due to the removal of fine metal debris and foreign substances in the pipes that deliver fluids such as hydraulic oil, lubricating oil and thermal oil. Temporary flushing equipment to remove debris uses fluid equipment of centrifugal pump and gear pump to prevent equipment accident of offshore platform. The equipment manufacturer requires the shipyard to have a cleanliness rating inside the pipe to meet the international standards ISO4406 and NAS1638 quality levels to prevent damage to the equipment sold. The quality of the internal flushing of pipes conforms to the regulations suggested by the equipment manufacturer. In this paper, three types of electric heater capacity, which is a method of evaporating and removing water inside a pipe during an oil flushing process, were compared. In addition, the study was conducted to remove the flushing oil in the pipe and to improve oil quality.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.1
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• pp.103-110
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• 2017

Most commercial vehicles have adopted the hydraulic power steering system. To reduce fuel consumption and to improve steering controllability, a hybrid electric power steering system is being developed for commercial vehicles. In this study, the HILS (Hardware In the Loop Simulation) system equipped with a commercial vehicle hybrid electric power steering system was developed and the vehicle dynamic performance of a truck with the steering system was evaluated. The hybrid electric power steering system is composed of the EHPS motor pump, column mounted EPS system, and ball nut steering gear box for heavy commercial vehicles. The accuracy of vehicle models equipped with the HILS system was verified with comparisons between the simulation results and field test results. The road reaction forces of the steering system were generated from the vehicle model and verified using field test results. Step steering tests using the verified HILS system were carried out and the performance of a newly developed commercial vehicle hybrid electric power steering system was evaluated.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.75-81
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• 1999

In this paper, the details of electronically controlled CVT is described , which Kia Motor company recently developed in prototype form for hybrid passenger car. This transmission has two input shafts, one for engine and the other for traction motor. The shaft for traction motor is located at rear side which is extended from primary pulley shaft and connected to traction motor through adapter gear box. Adopting two input system, various driving mode is available such as motor alone driving in hybrid vehicle application. As far as electrohydraulic system concerned , this transmission uses two bleed type variable force solenoids for line pressure and ratio control, and one on-off solenoid for clutch control. Another feature for this transmission is that oil pump for transmission is separate from CVT for supplying oil pressure even at vehicle standstill.