• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.96-101
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• 2001

This paper shows the temperature characteristics of a high speed angular contact ball gearing which is 7004C type with ISO P2 tolerance class. A built-in motor type high speed spindle which adopts an oil-air lubrication system was used to measure the temperature rise up to 60,000rpm. The gearing temperature was measured using thermocouples that were attached to the outside surfaces of the outer rings. The result showed that the continuous test method which was suggested in this paper is more effective than on and off method and the lubrication oil supply rate should be reduced in high speed rolling bearings as long as the seizure does not occur. And the result were confirmed that the bearings packed with ceramic balls are superior to those with steel balls in temperature characteristics.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.43-45
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• 2007

This Paper proposes a simple identification method of the moment of inertia for high performance spindle motor of machine tool. It uses the dynamic equation of a simple mechanical system, the torque reference of a speed controller, and the actual rotating speed of machine. The identified inertia can be for auto-tuning of the gains in the speed controller. The effectiveness of the proposed method is proved by the computer simulation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.646-650
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• 1996

In this paper, A hydrostatic bearing spindle for high precision machining and a motor built-in spindle for high speed machining are developed toobtain the high precision machining accuracy of the prototype lathe. The sliding bearing with fluoric resin (turcite) pad is adopted for improving the damping charateristics of guide ways. The funning accuracy of moving elements isestimated to confirm the validity of application on the prototype; the high precision CNC lathe. The surface roughness of Cupper and Aluminum machined by the hydrostatic spindle are 0.07 .mu. m and 0.10 .mu. mRmax. The surface roughness of Aluminium machined by the built-in spindle are 0.10 .mu. mRmax. From this results, it is venified that the prototype lathe is effective to high precision maching.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.307-311
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• 1997

This paper describes influence of thermal deformation on nosic characteristics in high speed spindle systems. Heat generation in front, rear spindle bearings and built in motor lead to diverse thermal deformation of headstock with time. This deformation changes assemble tolerance in bearing housing, especially to elliptic form. The elliptic assemble tolerance generate high nosie level with dominant amplitude in double rotational frequency.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.238-244
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• 2017

A spindle with a built-in motor can be used to simplify the structure of a machine tool system, but the rotor inevitably has unbalanced mass. This paper presents an analysis of the dynamic behavior. The spindle was used in a CNC lathe and investigated using the finite element method and transfer matrices. The high-speed spindle can be very sensitive to the rotation of an unbalanced mass, which has a harmful effect on many machine tools. Thus, a balancing procedure was performed with a spindle-bearing system for the CNC lathe by numerical analysis. The balancing was performed through the influence coefficient method, and the whirl orbit radii before and after balancing were compared to evaluate the effects. The results show that the rotational speed of the spindle seriously affects the whirl responses of the spindle. The whirl responses were also affected by other factors, such as the unbalanced mass and bearing stiffness. The balancing of the assembled spindle model significantly reduced the whirl orbit magnitude.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.4
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• pp.96-103
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• 1998

With the advance of processing technology , so as to spare fuel, piston heads used in automobile reciprocating engine have complex 3-dimension, with respect to shape such as ovality, profile, eccentricity, offset, recess. Therefore, coming out of the existing process work used master cam. the process work is performed using a CNC lathe. For a precision processing, the processing work is need to make study of high speed feed gear synchronized with the rotative speed of main spindle. And then the high speed feeding system must maintain high dynamic stiffness, high speed and high positioning accuracy . In this paper, in order to achieve high speed cutting tool feeding. The linear brushless DC motor is used for satisfying this process work. The ball bush and turicite is used as the guidance of the feed gear system. Also linear encoders, digital servo amplifiers and controller are used for controlling driving motor. This paper presents the design and simulation of the new tool feed system for noncircular machining.

• Composites Research
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• v.14 no.3
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• pp.77-89
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• 2001

Since the critical whirling vibration frequency of high speed built-in type motor spindle systems is dependent on the rotor mass of the built-in motor and the spindle specific bending modulus, the rotor and the shaft were designed using magnetic powder containing epoxy and high modulus carbon fiber epoxy composite, respectively. In order to increase the amount of the magnetic flux of the composite squirrel cage rotor of an AC induction motor, a steel core was inserted into the composite rotor. From the magnetic analysis, the optimal configurations of steel core and conductor bars for the dynamic characteristics of the rotor system were determined and proposed. The temperature dependence of composite squirrel cage rotor materials was investigated by various experiments such as TMA, DMA and VSM.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.2
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• pp.91-93
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• 2011

This paper is presented for the performance of the Fluid Dynamic Bearing(FDB) by the groove design and the tooling condition. Recently, spindle motors which require smaller size, lower sound noise, lower vibration, and higher speed of the rotation have been placed in high value-added products including Digital Lightening Processors(DLP), Hard Disk Drives(HDD), and ODDs. The spindle motors using the sintered porous metal bearing have higher vibration and acoustic noise by dry contact and large tolerance of the bearing parts. The Fluid Dynamic Bearing (FDB) with grooves is appropriate for spindle motors adequate in regards to mechanical vibration and acoustic noise. The paper shows the performance comparisons of between sintered porous metal bearing and FDB, and each FDBs according to the tooling deviations of grooves by the Finite Element Analysis(FEA) of the mechanical field. This paper shows the methods to make the grooves, the groove's depth, and the prototype of the motor with the fluid dynamic bearing. The performance characteristics of the grooves with the FDB are verified by the experimental results.

• Tribology and Lubricants
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• v.17 no.1
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• pp.10-15
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• 2001

Generally, it is said that the heat generation of air bearing is negligible. But the air bearing using at the built-in spindle is different from the general air bearing itself because of the thermal effects from the spindle motor and high-speed conditions. In this paper, in order to analysis the characteristics of air bearing by the heat, We made easy -heating-bearing-system (EHBS) and hard-heating-bearing-system (HHBS) and could identify the changes between the two bearing systems from the experiments and simulation. When spindle system reached at thermal steady-state, the changes means that the stiffness of air bearing becomes change due to the clearance change between bearing and journal. It is shown that the temperature rise and thermal effects to cause the thormal expansions have to be considered when designing air spindle system.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1179-1181
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• 2001

For high performance induction motor drives such as mill drives, elevator, spindle drive, NC and so on, smart speed controls is usually required, that requires a precise current control. This paper is proposes design of fuzzy controller which makes use of the output voltage of the space vector PWM inverter. Also, proposes the performance fuzzy controller for high performance vector control of induction motor drive system. The performance of a fuzzy controller is compared with that of an PI controller in an internal loop. The validity of the proposed technique is confirmed by simulation results for induction motor drive system.