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火车 轴承 拆装机 设计

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火车轴承拆装机设计,火车,轴承,拆装机,设计

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The Characterization and Experiment Research of Ultrasonic Rolling Machining for Column Surface Jinfu Dinga, Shiju Eb, Kehua Zhangc and Fujin Yud Institute of Machinery Equipment and Measurement & Control Technology, Zhejiang Normal University, JinHua 321004, China azsddif, besx_2001 , cmature, dzsdyfj Keywords: Ultrasonic vibration machining, Tool head, Rolling, Rolling characterization Abstract. The machining method and characteristic of the ultrasonic extrusion-rolling machining was introduced in the paper. According to the machining characteristic, the kinematic analysis of the machining mechanism and surface anamorphic was analyzed too. And then the correlative theory of tribology was adopted to discuss the relation between surface anamorphic quantity and the technological parameter. The theory foundation was afforded for the choice of technological parameter. Introduction The extrusion processing was a precision non-cutting machining method, and it was a metal surface reinforcement technic. The extrusion tools was made up of the hardness materials, in the processing, the tools vibrating on the workpiece surface and rolling the workpiece materials, it made the metal materials to generate perpetual deformation and enhance the hardness of the workpiece surface1. In recent years, the ultrasonic vibration processing was used largely for machining; the ultrasonic vibration was employed for rolling processing was a new technic method for finishing the workpiece surface, it would enhance the processing efficiency and improving the surface state 2. The toolhead of the tradition rolling machining and ultrasonic vibration finishing were the same, such as integral toolhead or welding toolhead 3,showed as Fig. 1, this structure a and b all not avoiding the toolhead accelerated wear. The c toolhead was design with a roller to avoiding accelerated wear and enlarge the work life. Use this toolhead in the rolling processing; the toolhead VS workpiece surface would take place rolling extrusion processing 4. In the paper kinematics and tribology theory were used to analysis the plasticity deformation, in order to research the relative between plasticity deformation and rolling parameter. Fig. 1 The schematic of the ultrasonic rolling device The rolling processing device and principle. The compose of the rolling processing device. The ultrasonic vibration rolling machining was designed according to the ultrasonic vibration principle; it was employed to carry the precision machining, using the super hard materials toolhead to reinforce and finishing processing the workpiece surface, this experiment was carried on the NC lathe. The device was showed in Fig. 1(2); it was composed of ultrasonic generator 8, transducer 6, amplitude transformer 5 and toolhead. The transducer translated the ultrasonic oscillation to mechanical vibration, and it were enlarged by the amplitude transformer and imparted energy to the toolhead for Advanced Materials Research Vols. 102-104 (2010) pp 559-563 (2010) Trans Tech Publications, Switzerlanddoi:10.4028/AMR.102-104.559All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of thepublisher: Trans Tech Publications Ltd, Switzerland, . (ID: 60-21/02/10,02:45:54) machining, the toolhead was screwed joint with the shell of the toolhead , the amplitude transformer made the roller to extrude the workpiece, so in processing the roller would generate relative rotation. The principle and characteristic. The ultrasonic signal were transformed and enlarged by the transducer and amplitude transformer, and then causing the toolhead vibrating, the workpiece were rolling processing by static pressure and impact load of the toolhead . So the asperity was planarization by the toolhead . The surface roughness was improved evidently and the residual compressive stress was generated. So the metal structure of workpiece was reinforced, the abrasion resistance, fatigue resistance, erosion resistance and mechanical properties were improved evidently 3, 5, 6. The ultrasonic rolling processing (USRP) have the characteristic: 1.extrusion characteristic, the static pressure on the toolhead would extrude the workpiece and cause plasticity deformation. 2. Impact characteristic, toolhead vibration would generated the effect of the shot peening 3, 5. 3. Rolling characteristic, in the ultrasonic rolling processing the roller generated roll on the workpiece. 4. Reduce the friction factor, in USRP the friction factor would be reduced by the toolhead vibration. Ultrasonic Vibration Rolling Mechanism Analysis Kinematic Model for the Rolling Processing. The mechanics model of ultrasonic rolling processing was shown as Fig. 2. When in vibration rolling processing, the ultrasonic sine wave that generated by ultrasonic generator was transferred to transducer, and enlarged by the amplitude transformer to come into being longitudinal mechanical vibrations. The vibration equation as follows 7, 8: sinyAt= (1) The vibration speed as follows: (2) Where A was the amplitude of the tools, was the angular velocity of the sine vibration, t was vibration time, and f was the frequency of the vibration. The Fig. 3 was the ultrasonic vibration speed curve. The speed of A and B was resolved into vertical direction and horizontal direction. The horizontal component was V cos and the vertical component was vibration speed of the tools, supposed the extrusion speed was V0, and the superposition extrusion speed and radial vibration speed as follows: sinVV=2 (3) 100VV=V +Vcos1V (4) Fig. 2 Schematic of the Rolling processing So the conclusion could obtain from the equation (3) and (4): 1. when t=k+/2,the roller of the toolhead was contacted with plastic deformation structure of the workpiece, the ultrasonic vibration phenomenon became complete obliteration, the instantaneous velocity of the extrusion velocity was the same value as the conventionality extrusion processing, this cos2cos(2)dyAtfAftdt=V560Digital Design and Manufacturing Technology velocity could call critical extrusion velocity. Apart from this, the ultrasonic vibration extrusion speed was obvious greater than the conventionality extrusion velocity. 2. The vertical component was the vibration velocity of the roller caused by the ultrasonic vibration. It caused the roller knocked on the workpiece surface regularly, the results was similar to the shot peening. Fig. 3 Schematic of the vibration speed curve The Deformation Procedure of the Metal Surface. The resemblance of the ultrasonic rolling processing and extrusion processing was the plasticity deformation of the metal; the contact stress must greater than yield strength of the workpiece materials 3. Fig. 4 The deformation process of the metal surface The static load was imposed on the workpiece surface, and combined with ultrasonic rolling, all of this action made the metal generating plasticity flow, and improved the surface state as Fig. 4 showed. The reasons of plasticity deformation were that: 1.with the static pressure, the ultrasonic rolling processing worked as the conventionality rolling process; 2. The vibration of the roller of the toolhead knocked on the workpiece surface acted as shot peening; 3. The ultrasonic rolling processing combined with the static pressure and the vibration impact improved the friction factor 4. Quantitative Analysis the Extrusion Deformation Before the ultrasonic rolling, the toolhead would be loaded a static pressure, namely static extrusion force 2, 3, 9. In the ultrasonic rolling processing, the static pressure and ultrasonic vibration extrusion force were combined with to process; the extrusion friction would be generated between the roller and workpiece, and there were relative rotation too. When the relative rotation was taken place, the relative motion between the roller and workpiece was the combination of roll, slide and rotation, so the elasticity deformation transform to the plasticity deformation took place on the surface of the workpiece. The contact pressure obeyed the Hertz distribution 4. The contact surface taken on the ellipse distribution, distribution the contact area would used the equivalent radii or curvature, showed Fig. 5. Because the ultrasonic rolling processing was a complex process, and the allowance was 0.010.02mm. In the productivity applications, in order to study the ultrasonic rolling processing parameter, the ultrasonic transducer decided the impact load 9. So the plasticity deformation in certain range were direct proportion the static pressure, the relative speed of the workpiece with tools, and were inverse variation with hardness of the surface. Advanced Materials Research Vols. 102-104561 Fig. 5 Schematic of Hertz contact Experiment Method and Results The processing technic experiment on the hydraulic prop was employed to validate the high-effective and practicability of the ultrasonic rolling processing (showed as Fig. 6). The workpiece materials were 27SiMn,97980mm，2731HRC. The conventional processing technic of hydraulic prop were lapping first and then polishing, the final needed surface roughness value was Ra 0.4m. In this experiment, the ultrasonic rolling processing was used to substrate the lapping and polishing. The experiment was carried on NC turning machine, the locale processing photo was shown in Fig. 6. The surface roughness value was measured by the Mahr S2. The finishing surface 500X photo was shown in Fig. 7. The test was carried after processing; the contrast result was shown in Fig. 8, the surface roughness reduced obviously. The surface roughness value was Ra 0.9 m before the processing, and the surface roughness reduced to Ra 0.1m by the ultrasonic rolling processing shown as Fig. 8. All in all, the ultrasonic rolling processing could meet the demand of the produce practice and the productive efficiency was enhanced obviously. Fig. 6 The photo of processor Fig. 7 The microscopy photo of processed surface Fig. 8 The measured value of surface roughness Ra (before processing Ra=0.9 and after processing Ra=0.1) 562Digital Design and Manufacturing Technology Conclusions In the paper, the ultrasonic rolling processing mechanism and characteristic were analyzed, the processing experiment were employed to validate the results that he ultrasonic rolling processing had more superiority than the general rolling processing, as follows: 1. The technic of ultrasonic rolling processing have the characteristic of impulsiveness and the energy crowding effect, so the processing result had not only the rolling characteristic but also the shot peening effect, it was favorable for improving the surface quality. 2. In the rolling processing, the ultrasonic vibration device improved the friction manner; the wear of the toolhe