氏名　DOMINIC S. GUEVARRA
学位の種類　博士（工学）
学位記番号　博甲第254号
学位授与の日付　平成14年8月31日
学位論文題目　DEVELOPMENT OF AUTOMATIC LAPPING PROCESS FOR HIGH PRECISION BALL SCREW　（高精度ボールねじの自動ラッピングプロセスの開発）
論文審査委員
　主査　教授　久曽神　煌
　審査委員　教授　高田　孝次
　審査委員　教授　柳　和久
　審査委員　助教授　太田　浩之
　審査委員　助教授　木村　哲也

• 論文目次
• 論文要旨

［平成14（2002）年度博士論文題名一覧］ ［博士論文題名一覧］に戻る．

Chapter 1 INTRODUCTION
1.1 Background　p.3
1.2 Objectives of the Study　p.5
1.3 Principle of Lapping Process　p.6
1.4 Accuracy of Ball Screw　p.7
1.5 Present Trend of Conventional Lapping Process　p.10
　1.5.1 Hand Lapping Operations　p.10
　1.5.2 Conventional Lapping Tool　p.12

Chapter 2 DEVELOPMENT OF THE NEW TYPE LAPPING TOOL
2.1 Details of the New Type Lapping Tool　p.13
2.1.1 Theoretical Analysis of Cylindrical Shaft and Ball Screw　p.13
2.1.2 Comparison of Profile Error between Cylindrical Shaft and Ball Screw　p.17
2.1.3 Design Consideration and Mechanism of the New Type Lapping Tool　p.18
　2.1.3.1 Descriptions of the Major Components　p.20
2.2 Experimental Apparatus and Method　p.24
2.2.1 Specifications of the Test Piece　p.24
2.2.2 Vertical-Type Automatic Lapping Machine　p.25
　2.2.2.1 Operating System of Automatic Lapping Machine　p.26
　2.2.2.2 Mechanisms of the Pneumatic Tool Carriage　p.27
2.2.3 Experimental Procedure　p.28
2.2.4 Test Measuring Instruments　p.30
　2.2.4.1 Automatic Lead Measuring Instrument　p.30
　2.2.4.2 Surface Roughness Test Instrument　p.31
2.2.5 Experimental Conditions　p.33
　2.2.5.1 Lapping and Measurement Range　p.34
2.3 Experimental Results and Discussion　p.35
2.3.1 Data Analysis of the New Type Lapping Tool　p.35
　2.3.1.1 Error on Travel　p.35
　2.3.1.2 Spatial Frequency Analysis　p.38
　2.3.1.3 Surface Roughness　p.40
2.3.2 Comparison of Results between Conventional and New Type Lapping Tool　p.42
　2.3.2.1 Error on Travel　p.42
　2.3.2.2 Spatial Frequency Analysis　p.44
　2.3.2.3 Surface Roughness　p.46
2.4 Summary　p.47

Chapter 3 DESIGN AND MANUFACTURE OF THE NEW TYPE AUTOMATIC LAPPING MACHINE
3.1 Description of the New Type Automatic Lapping Machine　p.48
3.1.1 Design Concept　p.48
3.1.2 Mechanism of the Lapping Tool Assembly　p.50
3.2 Experiment Apparatus and Procedure　p.51
3.2.1 Experimental Conditions　p.52
3.2.2 Test Measurements　p.53
3.3 Results and Discussion　p.54
3.3.1 Influence of Lapping Torque on Effective Diameter and Error on Travel　p.54
3.3.2 Analysis on Lead Errors　p.56
3.4 Summary　p.58

Chapter 4 OPTIMIZATION APPROACH FOR AUTOMATIC LAPPING PROCESS
4.1 Principle of New Lapping Process　p.59
4.2 Lapping Operation Control　p.60
4.3 Experimental Procedure　p.63
4.4 Experimental Results　p.63
4.4.1 Effective Diameter Analysis　p.63
4.4.2 Lead Accuracy Analysis　p.65
4.5 Summary　p.68

Chapter 5 CONCLUSIONS　p.69

REFERENCES　p.70

APPENDIX A MANUFACTURING PROCESSES　p.73
A.1 Machine Tools and Equipment Used　p.73
A.2 Fabrication Process Flow　p.74
A.3 Machining Operations Used　p.75

APPENDIX B LEAD ACCURACY OF THE BALL SCREWS　p.77
B.1 Permissible Values of Actual Mean Travel Errors and Travel Variations in Respect to Positioning Ball Screws　p.77
B.2 Permissible Values of Travel Variation in Respect to Positioning Ball Screws　p.77

APPENDIX C SAMPLING LENGTHS FOR SURFACE ROUGHLESS MEASUREMENT　p.78
C.1 Sampling Lengths for the Measurement of Ra of Non-Periodic Profiles　p.78
C.2 Sampling Lengths for the Measurement of Ry and Rz of Non- Periodic Profiles　p.78

APPENDIX D EXPERIMENTAL RESULTS FOR 8-AND 10-SLITS NEW TYPE LAP　p.79
D.1 Lead Accuracy Analysis　p.79
D.2 Spatial Frequency Analysis　p.81

　In recent years, development on advanced technology has continued to focus on methods for creating higher accuracy products and involves high precision processing which are becoming more important in various industrial applications. Likewise, with the progress of ultra-precision machine tools, metrological instruments and semiconductor equipment, the demand for high speed and positioning accuracy of the motion drive system are steadily increasing. There are many types of linear actuators that were developed and utilized in high precision manufacturing industry. The most popular among the driving mechanism is the ball screw, which is extensively used for linear motion transmitting application due to its high mechanical efficiency with superior accuracy, over the other linear motion actuators.
　In general, high precision ball screws are being lapped as a finishing method after grinding process by a highly skilled operator to improve the lead accuracy and screw profile in order to satisfy the high accuracy requirements in precision manufacturing applications. However, the existing manufacturing process is labor intensive that requires a highly skilled operator to carry out the manual lapping process using the conventional lapping tool which has two or three slits. These highly skilled operators have the capability to control and maintain the proper lapping condition particularly the lapping torque and speed, which depend on his feeling and judgment. Before lapping process, the operator must measure the workpiece to determine any deformation of screw shaft due to dimensional errors on effective diameter. The portion that has a large deflection along the effective threaded length will be mainly lapped to reduce the lead errors. Hence, it is difficult for a semi-skilled operator to perform such delicate machining operation.
　In this research, a new approach in lapping process is proposed to provide a potential alternative in methodology and technique for the high-precise ball screw generation. The purpose of this study is to establish a control and measurement system for the new type lapping machine that could perform both measuring and finishing process automatically. A new type horizontal lapping machine with in-process torque monitoring system and especially designed flexible lapping tool has been designed, manufactured and tested perform like a highly skilled operator. Therefore, this thesis reports on prototype development of an automatic lapping machine to determine its effectiveness and suitability as a new approach of manufacturing technique for ball screw. Based on the experimental results, it indicates that the new lapping machine could possibly control and improve the effective diameter, lead accuracy, lapping time and even surface finish. Consequently, this new machining system can be applied to increase productivity and cost-effectiveness in high precision manufacturing industry.