• 한국생산제조학회지
• /
• 제21권1호
• /
• pp.95-101
• /
• 2012

An internal type roller ring gear(RRG) system composed of either a pin or a roller ring gear and its conjugated cam pinion can improve the gear endurance from that of a conventional gear system by reducing the sliding contact, while increasing the rolling motion. In this paper, we first proposed the exact cam gear profile and the self-intersection conditions obtained when the profile shift coefficient is introduced. Then, we investigated contact stresses and surface pitting life to fmd characteristics for surface fatigue by varying the shape design parameters. The results show that the pitting life can be extended significantly by increasing the profile shift coefficient.

• 한국정밀공학회지
• /
• 제27권11호
• /
• pp.92-97
• /
• 2010

The object of this study is to investigate the definite method for pitting damaged surfaces. Pitting is a sort of fatigue damages and it is made by a repetitive load. For a judgment between damages or not, sensing vibrations of test equipment is simple. However, it is not only difficult to observe a growth of pitting but also impossible to detect the juncture of initial pitting. Therefore, a method for the pitting damaged area measuring technique was effectively implemented by Two Roller Machine. The change of surface damaged area was measured by an optical microscope in regular time and calculated by the use of dark and bright ratio of test specimens' pictures taken by optical microscope. In conclusion, S - N Curves gained by Failure rate - Cycle graph was led and the curves are able to be chosen as occasion demands for a failure area percentage.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2010년도 춘계학술대회 논문집
• /
• pp.1281-1282
• /
• 2010

• Tribology and Lubricants
• /
• 제27권1호
• /
• pp.40-44
• /
• 2011

The object of this study is to investigate influences of supplied lubricant quantities on spur gear's pitting life. Pitting is a sort of contact fatigue failures and made by a repetitive load. Basically, pitting is difficult to predict its life by an analysis due to many factors to be considered about tribology problems. In this paper, pitting life was proved by experiment using two roller machine. For a contact fatigue test, operating circumstances should be considered. During the test, temperature and lubricant quantities are considered and to investigate an influence of lubricant quantities, a comparison between optimally enough and not enough lubricant quantity was implemented.

• 대한기계학회논문집A
• /
• 제35권11호
• /
• pp.1453-1459
• /
• 2011

외접기어의 어느 한쪽 기어를 핀 또는 롤러로 대체한 롤러 피니언 기어 (RPG) 시스템은 기어 치물림 시 미끄럼 접촉을 줄이고 구름운동을 증대시켜 기어 내구성을 향상시킬 수 있다. 우선 본 논문에서는 전위계수(profile shift coefficient)를 고려하여 RPG 시스템의 캠 기어(cam gear)의 엄밀 치형설계 방법 및 치 꼬임으로 인한 간섭 방지조건을 제시하였다. 또 기어구동에 있어 치면에서 발생되는 진동이나 소음의 원인이 되는 피팅(pitting) 발생수명을 고려하기 위해, 설계인자의 변화에 따른 Hertz 접촉응력 및 하중응력계수(load stress factor)의 변화를 검토하였다. 이를 통해 RPG 시스템의 내구성을 향상시킬 수 있는 방안으로 전위계수의 증가를 제안하였다.

• 대한기계학회논문집A
• /
• 제36권11호
• /
• pp.1391-1397
• /
• 2012

하이포 트로코이드 기반의 CRG(Cam ring gear) 시스템은 핀 또는 롤러 치형을 가지는 기어와 공액인 캠 링기어로 구성된 내접기어 시스템이다. 본 논문에서는 CRG 시스템의 엄밀 치형설계를 바탕으로 기어 치면에서의 접촉특성을 분석하였으며 형상설계변수인 치형수정계수에 따른 기어의 내구수명을 검토하였다. 결과적으로 치형수정계수의 증가를 통해 기 설계된 CRG 시스템에 영향을 미치지 않으면서 기어의 접촉 피로수명을 향상시킬 수 있다.

• 한국생산제조학회지
• /
• 제21권2호
• /
• pp.283-289
• /
• 2012

Cam rack pinion (CRP) system which consists of cam rack and roller pinion transforms the rotation motion into linear one. The roller pinion has the plurality of rollers and meshes with its conjugated cam rack. The exact tooth profile of the cam rack and the non-undercut condition to satisfy the required performance have been proposed by introducing the profile shift coefficient. The load stress factors are investigated by varying the shape design parameters to predict the gear surface fatigue limit which is strongly related to the gear noise and vibration at the contact patch. The results show that the pitting life can be extended significantly by increasing the profile shift coefficient.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2009년도 춘계학술대회 논문집
• /
• pp.173-174
• /
• 2009

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 추계학술대회
• /
• pp.136-141
• /
• 2004

The gear in various mechanical components easily occurs at damages by the external torque. The main failure modes of the gear are surface pitting with the tooth surface and breakage with tooth root by caused fatigue. Therefore, the gear is very important role in the reliability research since it may cause fatal damage of entire system such as the gear box in automobile transmission. In this study, the failure mode of the gear was analyzed and accelerated durability analysis was employed for the life estimation of spur gears. In the case of assumed load spectrums, the reliability of spur gears was evaluated by inverse power law-Weibull accelerated life test model with cumulative damage exposure.

• Tribology and Lubricants
• /
• 제25권6호
• /
• pp.399-403
• /
• 2009

The objective of this paper is to predict pitting initiation by using a contact analysis and subsurface stress. Contact stresses are obtained by contact analysis of a semi-infinite solid based on the use of influence functions. Subsurface stress field is obtained using rectangular patch solutions. It is used Mesoscopic multiaxial fatigue criterion to predict contact fatigue life. It is important to predict pitting initiation to enhance reliability of the mechanical elements. Pitting life prediction in the spur gears which are fundamental mechanical element is presented in this paper.