• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.428-432
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• 2004

The important problem in the high speed spindles is to reduce and minimize the thermal effect by the motor and ball bearings. Thermal characteristics according to the bearing preload and hollow shaft cooling are studied for the test spindle with the oil mist lubrication and high frequency motor. Bearings and motor e main heat generation, and heat generation by ball bearings as a function of load, viscosity and gyroscopic moment effect are considered. Temperature distribution and thermal displacement according to the speed of spindle are measured by thermocouple and gap sensor. The results show that the fitting preload and hollow haft cooling are very effective to minimize the thermal effect by the motor and ball bearings.

• Journal of the Korean Society of Mechanical Technology
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• v.20 no.6
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• pp.751-756
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• 2018

A study on the weight reduction of a motor shaft in electric vehicle by using optimum design technique was carried out. The structural analysis of a motor shaft was performed by using ANSYS to investigate the structural safety. We also used HEEDS to find the optimal hollow shaft thickness. When the material of the hollow shaft is changed to SCM822H by using ANSYS 14.5 and HEEDS MDO, the weight could be reduced by about 53 % compared to the conventional solid one. From this study, the optimized dimensions of a hollow shaft were determined for light weight design.

• Progress in Superconductivity and Cryogenics
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• v.10 no.1
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• pp.57-61
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• 2008

A 1MW class HTS(High-Temperature Superconducting) synchronous motor has been developed. This motor was aimed to be utilized for industrial application such as large motors operating in large plants. The HTS field windings of the developed motor is cooled by way of Neon thermosiphon mechanism and the stator coil is cooled by water through hollow copper conductor. This paper describes performance test results of our motor, which was conducted at steady state in generator mode and motor mode.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.2
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• pp.417-423
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• 2012

In this paper, In order to make up for the weak point of driving structure that existing used single motor in motor design, as a method to make use of advantage for joint of hollow type, we propose implementation methods for high torque, high precision, backlash less, and design of secondary safety device, and application method through joint organization using multiple motors.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.138-143
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• 2005

The important problem in the high speed spindles is to reduce and minimize the thermal effect by the motor and ball bearings. Thermal characteristics according to the bearing preload and hollow shaft cooling are studied for the spindle with the oil mist lubrication and high frequency motor. Temperature distribution and thermal deformation according to the spindle speed, preload and flow rate are measured by thermocouple and gap sensor. Temperature distribution and thermal deformation are analyzed by using the finite element method. The results of analysis are compared with the measured data. This paper show that the suitable preload and hollow shaft cooling are very effective to minimize the thermal effect by the motor and ball bearings. This study indicates that temperature distribution and thermal deformation of the high speed spindle system can be estimated reasonably by using the three dimensional model through the finite element method and supports thermal optimization and more effective cooling method.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.6
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• pp.843-847
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• 2010

Recently, one of the most interesting issue in the intelligent robot and the industrial robot area is the design and an implementation of servo driver module based on motion network for hollow type joint module of all-in-one structure. In this paper, we designed and implemented for hollow type driver, and also verified the performance of the developed module through the experiment.

• Composites Research
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• v.12 no.2
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• pp.36-45
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• 1999

Since carbon fiber epoxy composite materials have excellent properties for structures due to their high specific strength, high modulus, high damping and low thermal expansion, the hollow shafts made of carbon fiber epoxy composites have been widely used for power transmission shafts for motor vehicles, spindles of machine tools and rollers for film manufacturing. However, the molded composite shafts are not usually accurate enough for mechanical machine elements, which require turning or grinding of composite hollow shafts. In this paper, the grinding characteristics of composite hollow shafts, which are flexible in the radial and circumferential directions, were investiaged experimentally and analytically with respect to the stacking angle, thickness and outer diameter.

• Progress in Superconductivity and Cryogenics
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• v.11 no.2
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• pp.33-36
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• 2009

A 1 MW class HTS (High-Temperature Superconducting) synchronous motor has been developed. This motor is aimed to be utilized for industrial application such as large motors operating in large plants. The HTS field coil of the developed motor is cooled by way of neon thermo siphonmechanism and the stator (armature) coil is cooled by water through hollow copper conductor. This paper also describes evaluation of some electrical parameters from performance test results of our motor, which was conducted at steady state in generator mode and motor mode. Open and short circuit tests were conducted in generator mode while a 1.1 MW rated induction machine was rotating the HTS machine. Electrical parameters such as mutual inductance and synchronous inductance are deduced from these tests. Load test was done upto rating torque during motor mode and efficiency was measured at each load torque.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.289-290
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• 2012

• Journal of Welding and Joining
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• v.18 no.5
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• pp.49-54
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• 2000

High speed rotating arc process, forming a flat bead surface with shallow penetration depth, can be applied to the automatic seam tracking, because the amplitude of current waveform increases at high rotation speed. Two high speed arc rotation mechanisms have been developed in Japan and Germany b rotating the electrode nozzle using an external motor, which are used prevalently for narrow gap and conventional seam welding. In this study, a new rotation mechanism was developed by using a hallow shaft motor designed to be installed in the electrode nozzle. By rotating the welding arc, the amplitude of current waveform increases remarkably since the self-regulation of arc is not fully performed. Experiments show that the arc sensor with high-speed rotation arc has improved its responsiveness and sensitivity.