ISU (In-arm hydropneumatic Suspension Unit) are popularly applied to recently developed tracked vehicles because of better performance of ISU than the one of the conventional HSU (Hydraulic Suspension Unit). However, function deterioration and malfunction phenomena of the several ISUs were observed due to leakage of hydraulic fluid during operation of the tracked vehicles. The objective of this study is the investigation of fundamental leakage mechanism of hydraulic fluid for the ISU. The leakage mechanism was investigated by comparing both results of the technical data analysis and overhaul inspection of the ISU which occurred leakage of hydraulic fluid. Finally, the leakage mechanism found in the current investigation was verified by using experimental methods.

ABSTRACT
 1. 서 론
 2. ISU의 구조 및 작동
  2.1 ISU 구조
  2.2 ISU 작동
 3. 작동유 누유 발생 분석
  3.1 작동유 누유 경로
  3.2 작동유 누유품 분석 결과
  3.3 씰 관련 문헌 검토 결과
  3.4 누유 메카니즘규명
 4. 누유 메카니즘 검증
 5. 결 론
 References

• 김형현(Defense Agency for Technology and Quality) | Hyeong-Hyeon Kim Corresponding Author