• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.647-650
• /
• 2001

In case of bent axis type axial piston hydraulic pump or motor, hydrostatic bearing used to achieve the lubrication effect on the mechanical sliding contact areas between the following pairs ; piston shoe and swash plate, valve plate and cylinder block, piston and cylinder block, etc. In this research, we designed two pairs of spherical ball joint in witch connecting rod piston end. The one is not hydrostatic bearing, the other is designed with spherical hydrostatic bearing in point of view minimum pumping power loss. By varying supply pressure on the piston, we can know that it is possible to reduce the friction torque by using hydrostatic bearing designed one. Finally, by comparing the results of driving torque between the two models, it was verified that the spherical hydrostatic bearing is well designed.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.805-809
• /
• 2003

We developed a human-sized BWR(biped walking robot) named KUBIR1 driven by a new actuator based on the ball screw which has high strength and high gear ratio. KUBIR1 was developed to walk autonomously such that it is actuated by small torque motors and is boarded with DC battery and controllers. To utilize the information on the human walking motion and to analyze the walking mode of robot, a motion capture system was developed. The system is composed of the mechanical and electronic devices to obtain the joint angle data. By using the obtained data, a 3-D graphic interface was developed based on the OpenGL tool. Through the graphic interface, the control input of KUBIR1 is performed.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.9 no.4
• /
• pp.8-13
• /
• 2010

The constant velocity internal grinding is a popular process for studying axle machine design and process in automobile industry. In this study, The program which gives the data of wheel size and truing diameter of ball groove is developed. As a result I obtained the data of grinding conditions makes good surface roughness get a grinding conditions. The grinding characteristics and conditions of constant velocity joint were investigated with respect to grinding feed, cutting depth, grinding time. At machine failure, the results were suddenly increased and the detailed surfaces were extremely obtained. Grinding condition was big more affected by grinding depth, grinding speed and grinding time.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.486-489
• /
• 2003

To reduce lateral force of traditional plunger type piston in the swash plate type hydraulic piston pumps and motors, we have proposed rod type piston with ball joint on both ends. We have studied the theoretical reaction force on two types of piston moving in the cylinder block bore. and made an experiment for the resistance force measurement on a reciprocating motion of plunger and rod type piston, changing the test condition such as swash plate angel and supply oil pressure and so on. As a result. a rod type piston has more smaller resistance force, about 29%. than a plunger type one.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.24 no.4
• /
• pp.561-569
• /
• 2000

The purpose of this study is to construct a testing equipment with which several characteristics of the domestically developed swashplate type axial piston motor can be tested and to develop a software with which the data from experiment can be stored and can be applied. The results of the study are as follows; 1) The leakage flow and the torque of the motor being stopped is propotional to supply pressure and their relation can be showed by linear equations. 2) The motor movement is not smooth below 50 rpm but it moves smoothly up 170 rpm. 3) When the motor starts or stops, the pressure rise ratio effects decisively to the max. torque.

• Journal of the Korean housing association
• /
• v.14 no.5
• /
• pp.105-116
• /
• 2003

The purpose of this study is to suggest the method of prevention of staircase accidents, and to make housing environment better through researching the dimension of a housing staircase for Korean. The scope and method of this thesis is to investigate the dimension limits of a staircase (slope, minimum width of tread, maximum height of riser), and to analyze the characteristics of foot condition (jutting rate, foot angle, ball joint, nosing clearance, clearance distance) using the experiment which takes a photograph of foot motion during walking stairs. The results of this thesis are as follows. The slope of a staircase in house is $32.3^{\circ}$$^{\circ}$-$42.1^{\circ}$$^{\circ}$. The riser should be less than 190 mm. The minimum size of tread is 210 mm and proper size is 270 mm.

• Journal of Korean Foot and Ankle Society
• /
• v.20 no.1
• /
• pp.36-38
• /
• 2016

Tarsal coalition is an abnormal union between two or more bones of the hind- and mid-feet, which can occur at various rates from cartilaginous to osseous union. Talonavicular coalition is reported less frequently than calcaneonavicular or talocalcaneal coalition and has been associated with various abnormalities, including symphalangism, clinodactyly, ray anomaly, clubfoot, other tarsal coalitions, and a ball-and-socket ankle joint. Patients with talonavicular coalitions are usually asymptomatic and rarely require surgical treatment. We review the literature and report on a case of 59-year-old male patient with talonavicular coalition.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1994.10a
• /
• pp.648-652
• /
• 1994

Lower Arm은 전차축식 현가장치에 사용되는 자동차부품으로 바퀴에서 발생되는 제동력이나 코너링력 등을 지탱하는 장치이다. V형의 상하 2개의 서스펜션암의 축에 의해 츠레임에 장착되고 좌우에 있는 Lower Arm끝부분은 볼조인트 및 부싱에 의해 스티어링 너클에 부착된다. 압입부품들은 자동차의 주행중 발생하는 외력에 의하여 이탈될 수 있는 위험성에 항상 노출되어 있어 자동차에 사용하는 압입부품들의 이탈력은 매우 중요하지만 한번 이탈시킨 Lower Arm은 이탈력이 현저히 저하되기 때문에 이탈력 측정에 의한 품질관리는 전량검사가 불가능하게 된다. 본 연구는 Lower Arm에 압입되는 볼조인트의 압입력을 압입거리에 따라 측정하여 Lower Arm에 뚫어진 볼조인트 압입구멍의 크기와 압입력의 상관관계를 실험적으로 구할수 있는 크기와 압입력의 상관관계를 실험적으로 구할 수 있는 모니터링 시스템을 개발하고자 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.507-510
• /
• 2002

We developed a human-sized BWR(biped walking robot) named KUBIRI driven by a new actuator based on the ball screw which has high strength and high gear ratio. KUBIRI was developed to walk autonomously such that it is actuated by small torque motors and is boarded with DC battery and controllers. To utilize informations on the human walking motion and to analyze the walking mode of robot, a motion capture system was developed. The system is composed of the mechanical and electronic devices to obtain the joint angle data. By using the obtained data, a 3-D graphic interfacer was developed based on the open inventor tool. Through the graphic interfacer, the control input of KUBIRI is performed.

• Journal of the Korean Society for Precision Engineering
• /
• v.31 no.6
• /
• pp.535-541
• /
• 2014

In this research, three degree-of-freedom parallel spherical robot is developed for an artificial eyeball. The proposed system is comprised of a moving and a base plate, three prismatic actuators, and a ball joint for an angular movement of the moving plate. The vector analysis is employed to investigate the relationship between positions of the actuators and a pose of the moving plate. The required ranges for every actuators are calculated using the derived inverse kinematics in regard to the combination of two different levels for the size of the system component. Then the size of every components is determined from the analyzed trend. PI controller is employed for the position control of the moving plate. Finally the proposed system is verified using an arbitrary path of the angular movement.