표제지

목차

ABSTRACT 13

Ⅰ. 서론 16

1.1. 연구 배경 16

1.2. 연구 동향 21

1.2.1. 구름 베어링의 마찰 토크에 관한 연구 21

1.2.2. 구름 베어링의 내구 수명에 관한 연구 22

1.2.3. 변속기의 효율 개선에 관한 연구 22

1.3. 연구 목적 및 연구 내용 24

1.3.1. 연구 목적 24

1.3.2. 연구 내용 24

Ⅱ. 이론적 배경 27

2.1. 자동변속기의 구조 및 베어링 종류 27

2.1.1. 자동변속기의 구성요소 27

2.1.2. 자동변속기의 변속원리 29

2.1.3. 자동변속기용 베어링의 종류 32

2.2. 자동변속기용 베어링의 작용 하중 36

2.2.1. 헬리컬 기어 발생 하중 36

2.2.2. 유성기어용 베어링(planetary gear bearing, K1~K4) 38

2.2.3. 스러스트 니들 롤러 베어링(T1~T7) 41

2.2.4. 트랜스퍼 드라이브 기어 베어링(B1) 42

2.2.5. 아웃풋 샤프트용 베어링(R1, R2) 43

2.2.6. 디퍼렌셜 샤프트용 베어링(R3, R4) 45

2.3. 구름 베어링의 정격 수명 47

2.3.1. 볼 베어링(B1) 47

2.3.2. 롤러 베어링(K1~K4, T1~T7, R1~R4) 51

2.4. 구름 베어링의 정적 강도 54

2.5. 구름 베어링의 마찰 토크 56

2.5.1. 구름 저항 56

2.5.2. 미끄럼 마찰 59

Ⅲ. 본론 62

3.1. 수치 해석 조건 설정 62

3.1.1. 작동 온도 및 윤활 조건 62

3.1.2. 베어링 장착 예압 및 틈새 조건 65

3.1.3. 차량 주행 조건과 부하 조건 69

3.2. 기존 설계에 대한 수치 해석 결과 74

3.2.1. 유성기어 지지용 베어링(K1~K4) 74

3.2.2. 스러스트 니들 롤러 베어링(T1~T7) 79

3.2.3. 트랜스퍼 드라이브 기어 베어링(B1) 83

3.2.4. 테이퍼 롤러 베어링(R1~R4) 86

3.2.5. 베어링 수치 해석 결과 90

3.3. 효율 개선 설계 95

3.3.1. 효율 개선 설계 인자 선정 95

3.3.2. 복열 앵귤러 컨택트 볼 베어링(B1) 101

3.3.3. 테이퍼 롤러 베어링(R1~R4) 103

3.3.4. 스러스트 니들 롤러 베어링(T1~T7) 109

3.3.5. 효율 개선 설계 해석 결과 113

3.4. 개선 설계에 대한 시험 평가 115

3.4.1. 베어링 마찰 토크 시험 검증 115

3.4.2. 베어링 피로 수명 시험 평가 127

3.4.3. 베어링 정적 강도 시험 평가 142

Ⅳ. 결론 149

1) 자동변속기용 베어링의 하중 조건 설정 방법 제시 149

2) 자동변속기용 베어링의 정격 수명 및 동력 손실 수치 해석 149

3) 자동변속기용 베어링의 동력 손실 저감 설계 방법 제시 150

4) 자동변속기용 베어링의 시험 평가 150

참고문헌 151

Table 2.1. Gear ratio calculation of a planetary gear set 30

Table 2.2. Bearing applications on the automatic transmission 33

Table 2.3. Life modification factor for reliability 50

Table 3.1. Test results of the bearing temperature 63

Table 3.2. Operating condition of the lubricant 64

Table 3.3. Boundaiy condition of the operating clearance calculation 67

Table 3.4. Operating condition of the clearance 68

Table 3.5. Parameters of the driving resistance torque calculation 72

Table 3.6. Gear ratio and speed range of the transmission 72

Table 3.7. Classification of load data 73

Table 3.8. Specification of the radial needle roller bearings for planetaiy gear sets 75

Table 3.9. Calculation results of the radial needle roller bearings for planetary gear sets 78

Table 3.10. Specification of the thrust needle roller bearing 81

Table 3.11. Calculation results of the thrust needle roller bearing 82

Table 3.12. Specification of the transfer drive gear bearing 83

Table 3.13. Calculation results of the transfer drive gear bearing 85

Table 3.14. Specification of the tapered roller bearing 86

Table 3.15. Calculation results of the tapered roller bearing 89

Table 3.16. Design variants of the transfer drive gear bearing 101

Table 3.17. Design variants of the output shaft front bearing 105

Table 3.18. Design variants of the output shaft rear bearing 106

Table 3.19. Design variants of the differential shaft front bearing 107

Table 3.20. Design variants of the differential shaft rear bearing 108

Table 3.21. Design variants of the thrust needle roller bearing 111

Table 3.22. The power loss calculation results of the thrust needle roller bearing 112

Table 3.23. Friction torque test conditions for the angular contact ball bearing 116

Table 3.24. Friction torque test conditions for the taper roller bearing 119

Table 3.25. Friction torque test conditions for the thrust needle roller bearing 124

Table 3.26. Rating life test conditions for the angular contact ball bearing 128

Table 3.27. Rating life test conditions for the tapered roller bearing 132

Table 3.28. Rating life test results for the tapered roller bearing, R1 134

Table 3.29. Rating life test results for the tapered roller bearing, R2 135

Table 3.30. Rating life test results for the tapered roller bearing, R3 137

Table 3.31. Rating life test conditions for thrust needle roller bearings 140

Table 3.32. Static strength test conditions for the angular contact ball bearing 143

Table 3.33. Static strength test conditions for tapered roller bearings 145

Table 3.34. Static strength test conditions for thrust needle roller bearings 146

Fig. 1.1. Historical fleet CO2 emissions performance and cuirent standards for passenger cars 16

Fig. 1.2. Fleet Specification of passenger car fleet 20

Fig. 1.3. Loss percentage of automatic transmission components 20

Fig. 1.4. Study procedure for the durability evaluation and the efficiency improvement technique of bearings in an automatic transmission 26

Fig. 2.1. Components of an automatic transmission 28

Fig. 2.2. Assembly of a planetary gear set 31

Fig. 2.3. Schematic diagram of planetary gear sets for the automatic transmission 31

Fig. 2.4. Application of bearings in the automatic transmission 32

Fig. 2.5. Assembly of the transfer drive gear bearing 34

Fig. 2.6. Assembly of the tapered roller bearing 34

Fig. 2.7. Assembly of the thrust needle roller bearing 35

Fig. 2.8. A helical gear set 37

Fig. 2.9. Loads transmitted by a helical gear 37

Fig. 2.10. Application of planetary gear bearings 38

Fig. 2.11. Loads transmitted by a planetaiy gear 40

Fig. 2.12. Static equilibrium of pinion gear loads 40

Fig. 2.13. Schematic diagram of a planetary gear operation 40

Fig. 2.14. Application of thrust needle roller bearings in the automatic transmission 41

Fig. 2.15. Static equilibrium of the transfer gear shaft system 42

Fig. 2.16. Output shaft of the automatic transmission 44

Fig. 2.17. Static equilibrium of the output shaft system 44

Fig. 2.18. Differential shaft of the automatic transmission 46

Fig. 2.19. Static equilibrium of the differential shaft system 46

Fig. 2.20. Bearing internal load distribution 49

Fig. 2.21. Auxiliaiy geometiy parameters 50

Fig. 2.22. Load distribution on laminas 53

Fig. 2.23. The dynamic equivalent load on a lamina 53

Fig. 2.24. Load distribution of rolling elements 55

Fig. 2.25. The maximum contact pressure of static condition 55

Fig. 2.26. Rolling deformation in roller-raceway contact 56

Fig. 2.27. Hysteresis loop for elastic material 57

Fig. 2.28. Compression of lubricant 58

Fig. 2.29. Sliding Speed in the contact area 59

Fig. 2.30. Spin on ball bearings 60

Fig. 2.31. Sliding friction on tapered roller bearings 61

Fig. 3.1. The Stribeck curve 63

Fig. 3.2. Measuring of the operating temperature in automatic transmission 63

Fig. 3.3. Churning losses of the lubricant 64

Fig. 3.4. Intemal clearance of the bearing 65

Fig. 3.5. Fitting condition of the bearing 66

Fig. 3.6. Preload changes of the tapered roller bearing 66

Fig. 3.7. Preload calculation results of the tapered roller bearing 68

Fig. 3.8. Contributing factors of total driving resistance torque 71

Fig. 3.9. New european driving cycle 71

Fig. 3.10. BEARINX modeling of the automatic transmission system 74

Fig. 3.11. Results of contact pressure calculation on pinion bearings 76

Fig. 3.12. Results of contact pressure calculation on thrust needle roller bearings 81

Fig. 3.13. Modeling of the main shaft system 84

Fig. 3.14. Results of contact pressure calculation on the transfer drive bearing 84

Fig. 3.15. Modeling of the output shaft 88

Fig. 3.16. Modeling of the differential shaft 88

Fig. 3.17. Calculation results of the equivalent load 90

Fig. 3.18. Calculation results of the equivalent speed 91

Fig. 3.19. Calculation results of the contact pressure 92

Fig. 3.20. Calculation results of the rating life 93

Fig. 3.21. Calculation results of the power loss 94

Fig. 3.22. Design parameters for friction torque 97

Fig. 3.23. Down sizing of the tapered roller bearing 98

Fig. 3.24. The reference diameter of the ball bearing 98

Fig. 3.25. The friction torque by the roughness 100

Fig. 3.26. The profile of the tapered roller bearing 100

Fig. 3.27. The contact angle of the angular contact ball bearing 101

Fig. 3.28. The rating life and the power loss of the transfer drive gear bearing 102

Fig. 3.29. Design parameters of the tapered roller bearing 104

Fig. 3.30. The rating life and the power loss of the output shaft front bearing 105

Fig. 3.31. The rating life and the power loss of the output shaft rear bearing 106

Fig. 3.32. The rating life and the power loss of the differential shaft front bearing 107

Fig. 3.33. The rating life and the power loss of the differential shaft rear bearing 108

Fig. 3.34. Design parameters of the thrust needle roller bearing 110

Fig. 3.35. The contact pressure and the power loss of the main bearings 113

Fig. 3.36. The contact pressure and the power loss of the thrust needle roller bearings 114

Fig. 3.37. Power loss of bearings in an automatic transmission 114

Fig. 3.38. The test rig of friction torque on the angular contac ball bearing 116

Fig. 3.39. Friction torque test results of the current bearings and new bearing on the angular contact ball bearing 117

Fig. 3.40. The test rig of friction torque on the tapered roller bearing 119

Fig. 3.41. Friction test torque results of the current bearings and new bearing on the output shaft front bearing 120

Fig. 3.42. Friction torque test results of the current bearings and new bearing on the output shaft rear bearing 120

Fig. 3.43. Friction torque test results of the current bearings and new bearing on the differential shaft bearing 121

Fig. 3.44. The test rig picture of friction torque on the thrust needle roller bearing 123

Fig. 3.45. The test rig drawing of friction torque on the thrust needle roller bearing 123

Fig. 3.46. Friction torque test results of the current bearings and new bearing on the T1 trust needle roller bearing 125

Fig. 3.47. Friction torque test results of the current bearings and new bearing on the T5 trust needle roller bearing 125

Fig. 3.48. Friction torque test results of the current bearings and new bearing on the T7 trust needle roller bearing 126

Fig. 3.49. The test rig of the rating life on the angular contact ball bearing 129

Fig. 3.50. The test rig picture of the rating life on the angular contact ball bearing 129

Fig. 3.51. Disassembly analysis of tested bearing B1 130

Fig. 3.52. The test rig of the rating life on the tapered roller bearing 133

Fig. 3.53. Disassembly analysis of tested bearing R1 134

Fig. 3.54. Disassembly analysis of tested bearing R2 136

Fig. 3.55. Disassembly analysis of test bearing R3 137

Fig. 3.56. The test rig of the rating life on thrust needle roller bearings 139

Fig. 3.57. The test rig picture of the rating life on thrust needle roller bearings 139

Fig. 3.58. Disassembly analysis of tested bearing T1 141

Fig. 3.59. The test rig of the rating life on the angular contact ball bearing 143

Fig. 3.60. Measuring results of the rolling elements defbnnation on angular contact ball bearings 144

Fig. 3.61. The test rig of the static strength on thrust needle roller bearings 147