• Title/Summary/Keyword: Angular contact ball bearing

Search Result 67, Processing Time 0.02 seconds

Air Cooling Characteristics of a High Speed Spindle System for Machine Tools (공작기계용 고속주축계의 공기냉각특성에 관한 연구)

  • Choi, Dae-Bong;Kim, Suk-Il;Song, Ji-Bok
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.11 no.1
    • /
    • pp.123-128
    • /
    • 1994
  • A high speed spindle system for machine tools can be used to reduce the machining time, to improve the machining accuracy, to perform the machining of light metals and hard materials, and to unite the cutting and grinding processes. In this study, a high speed spindle system is developed by applying the oil-air lubrication method, angular contact ball bearings, injection nozzles with dual orifices, cooling jacket and so on. And an air cooling experiment for evaluating the performance of the spindle system is carried out. Especially, in ofder to establish the air cooling conditions related to the development of a high speed spindle system, the effects of cooling air pressure, oil supply rate, air supply rate and rotational spindle speed are studied and discussed on the bearing temperature rise and frictional torque. Also the effects of cooling air pressure, rotational spindle speed and spindle system structure is investigated on the bearing temperature distribution. The experiment on the test model reveals the usefulness of the air cooling method.

  • PDF

Dynamic Analysis of Spindle Supported by Multiple Bearings of Different Types (복합베어링으로 지지된 스핀들의 동적 해석)

  • Tong, Van-Canh;Bae, Gyu-Hyun;Hong, Seong-Wook
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.32 no.2
    • /
    • pp.117-125
    • /
    • 2015
  • This paper presents a dynamic modeling method for the indeterminate spindle-bearing system supported by multiple bearings of different types. A spindle-bearing system supported by ball and cylindrical roller bearings is considered. The de Mul's bearing model is extended for calculating ball and cylindrical roller bearing stiffness matrices with inclusion of centrifugal force and gyroscopic moment. The dependence between spindle shaft reaction forces and bearing stiffness is effectively resolved using an iterative approach. The spindle rotor dynamics is established with the Timoshenko beam theory based finite elements. The spindle reaction forces, bearings stiffness and spindle natural frequencies are obtained with taking into account spindle radial load, ball bearing axial preload and rotational speed effects. The developed method is verified by comparing the simulation results with those from a commercial program.

볼베어링 발열에 관한 실험적 고찰

  • 나희형;임윤철
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • 1997.04a
    • /
    • pp.190-197
    • /
    • 1997
  • The heat generation of angular contact ball bearings and deep groove ball bearings is studied with experiment and simulation. The temperature variation of inner, outer races and the temperature incresement distribution are measured by using thermocouples for the shaft speed, preload, viscosity of lubrucant and lubrication method. The measured values from experiment are used to estimate the heat generation rate. Oil-air lubrication using oils with different viscosities and grease lubrication are adopted.

  • PDF

A Study on the Oil-Jet Lubrication Characteristics of a Motor-Integrated High-Speed Spindle System with $\phi$65mm$\times$25,000rpm (오일제트윤활방식의 25,000rpm급 모터내장형 고속주축계의 윤활특성에 관한 연구)

  • 이용희;김석일;김태형;박보선
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.15 no.5
    • /
    • pp.59-64
    • /
    • 1998
  • In this study, a motor-integrated high-speed spindle system with $\psi$65mm $\times$ 25,000rpm is developed by introducing the oil-jet lubrication method, ceramic angular contact ball bearings, a built-in motor and so on. And oil-jet lubrication experiments fur evaluating the system performance are performed under various operation conditions. Especially, in order to establish the oillet lubrication conditions related to the development of a high-speed spindle system, the effects of oil supply rate and rotational spindle speed are investigated on the temperature rise, temperature distribution, motor current and so on.

  • PDF

Efficiency Improvement of Transfer Drive Gear Bearings for an Automotive Automatic Transmission (승용차 자동변속기용 트랜스퍼 드라이브 기어 베어링의 효율개선 방법에 관한 연구)

  • Lee, In Wook;Han, Sung Gil;Gwak, Beom-Seop;Lee, Ho Sung;Song, Chul Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.20 no.3
    • /
    • pp.40-46
    • /
    • 2021
  • An automatic transmission of automobiles enables comfortable driving experience with lower transmission shifting jerks. However, the assembly structure is more complicated and requires additional components with lower efficiency than the manual transmission system. Extensive research has been conducted to improve the overall transmission efficiency by optimizing each component of the automatic transmission assembly. This study focuses on enhancing the friction torque of double angular contact ball bearings used in automatic transmission. The friction torque of the bearing varies with the operating conditions such as the operational load and rotating speed. Since reducing the friction torque of the bearing tends to deteriorate the durability of the bearing, it is necessary to design the bearing having a minimum required friction torque by determining the durability life of an automatic transmission assembly, In this study, the theoretical life and friction torque of conventional and newly-developed bearings are calculated. The difference in the friction torque between the new and existing bearings are also evaluated.

Thermal Characteristic Analysis of a High-Speed Horizontal Machining Center with Built-in Motor and Linear Motors (내장형 모터와 리니어 모터를 적용한 초고속 수평형 머시닝센터의 열 특성 해석)

  • 김석일;조재완
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2004.04a
    • /
    • pp.416-423
    • /
    • 2004
  • This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m/fin. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

  • PDF

Thermal Characteristic Analysis of a High-Speed Horizontal Machining Center with Built-in Motor and Linear Motors (내장형 모터와 리니어 모터를 적용한 초고속 수평형 머시닝센터의 열 특성 해석)

  • Kim Seok-ll;Cho Jae-Wan
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.13 no.5
    • /
    • pp.30-37
    • /
    • 2004
  • This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m/min. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

Design Methodology of Automotive Wheel Bearing Unit with Discrete Design Variables (이산 설계변수를 포함하고 있는 자동차용 휠 베어링 유닛의 설계방법)

  • 윤기찬;최동훈
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.9 no.1
    • /
    • pp.122-130
    • /
    • 2001
  • In order to improve the efficiency of the design process and the quality of the resulting design, this study proposes a design method for determining design variables of an automotive wheel-bearing unit of double-row angular-contact ball bearing type by using a genetic algorithm. The desired performance of the wheel-bearing unit is to maximize system life while satisfying geometrical and operational constraints without enlarging mounting spae. The use of gradient-based optimization methods for the design of the unit is restricted because this design problem is characterized by the presence of discrete design variables such as the number of balls and standard ball diameter. Therefore, the design problem of rolling element bearings is a constrained discrete optimization problem. A genetic algorithm using real coding and dynamic mutation rate is used to efficiently find the optimum discrete design values. To effectively deal with the design constraints, a ranking method is suggested for constructing a fitness function in the genetic algorithm. A computer program is developed and applied to the design of a real wheel-bearing unit model to evaluate the proposed design method. Optimum design results demonstrate the effectiveness of the design method suggested in this study by showing that the system life of an optimally designed wheel-bearing unit is enhanced in comparison with that of the current design without any constraint violations.

  • PDF

Genetic-Based Combinatorial Optimization Method for Design of Rolling Element Bearing (구름 베어링 설계를 위한 유전 알고리듬 기반 조합형 최적설계 방법)

  • 윤기찬;최동훈;박창남
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • 2001.11a
    • /
    • pp.166-171
    • /
    • 2001
  • In order to improve the efficiency of the design process and the quality of the resulting design for the application-based exclusive rolling element bearings, this study propose design methodologies by using a genetic-based combinatorial optimization. By the presence of discrete variables such as the number of rolling element (standard component) and by the engineering point of views, the design problem of the rolling element bearing can be characterized by the combinatorial optimization problem as a fully discrete optimization. A genetic algorithm is used to efficiently find a set of the optimum discrete design values from the pre-defined variable sets. To effectively deal with the design constraints and the multi-objective problem, a ranking penalty method is suggested for constructing a fitness function in the genetic-based combinatorial optimization. To evaluate the proposed design method, a robust performance analyzer of ball bearing based on quasi-static analysis is developed and the computer program is applied to some design problems, 1) maximize fatigue life, 2) maximize stiffness, 3) maximize fatigue life and stiffness, of a angular contact ball bearing. Optimum design results are demonstrate the effectiveness of the design method suggested in this study. It believed that the proposed methodologies can be effectively applied to other multi-objective discrete optimization problems.

  • PDF