• 한국생산제조학회지
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• 제19권5호
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• pp.678-683
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• 2010

The drum cam with rotational follower is used to apply the ATC and index table of machine tools and it has the merit of minimizing the backlash. In general, to machine the drum cam with rotational follower, 5-axis CNC machine must be used and its kinematic principle must be included in modeling on CAM. So, the commercialized CAM software can't be applied to this machining of drum cam. Though some special software for machining drum cam was developed, it could be applied to special 5-axis CNC machine tools and the finish machining module was not applied. To solve this problem, this study includes the induction of the post processing algorithm for the rough machining of drum cam on several 5-axis CNC machine tools, type AC, AB and Be. The finish machining software will be treated in next study. A sample drum cam was machined on 5-axis CNC machine tool of AC type. The designed geometric profile of drum cam consist to the measured profile after machining well. This post processing algorithm for rough machining of the drum cam was clearly verified.

• 한국생산제조학회지
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• 제19권5호
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• pp.684-690
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• 2010

A drum cam with rotational follower has a cam mechanism and it is mainly used in its application such as index table and ATC of machine tool. Also its use can reduce the backlash in its kinematic movement. To machine the drum cam with rotational follower, 5-axis CNC machine tool is generally used and its kinematic principle is included in it's design. Until now, the commercialized CAM software can't cover the application of the drum cam machining. Even if, some special software was developed for machining a drum cam, the post processing method for finish machining was not developed yet. And to overcome the problem, the form tool is still used on the tool path of rough machining. This study includes the induction of the post processing technique for the finish machining of drum cam on three 5-axis CNC machine tools, type AC, AB and BC. To prove the finishing geometric profile, the result was clearly verified through inspection and geometric measurement after direct machining of the drum cam in AC type 5-axis machine tool in this study.

• Structural Engineering and Mechanics
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• 제16권5호
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• pp.533-556
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• 2003

The flutter and buckling analysis of a beam structure subjected to a static follower force is completely studied in the paper. The beam is fixed in the transverse direction and constrained by a rotational spring at one end, and by a translational spring and a rotational spring at the other end. The co-existence of flutter and buckling in this beam due to the presence of the follower force is an interesting and important phenomenon. The results from this theoretical analysis will be useful for the stability design of structures in engineering applications, such as the potential of flutter control of aircrafts by smart materials. The transition-curve surface for differentiating the two distinct instability regions of the beam is first obtained with respect to the variations of the stiffness of the springs at the two ends. Second, the capacity of the follower force is derived for flutter and buckling of the beam as a function of the stiffness of the springs by observing the variation of the first two frequencies obtained from dynamic analysis of the beam. The research in the paper may be used as a benchmark for the flutter and buckling analysis of beams.

• 대한기계학회논문집A
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• 제27권8호
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• pp.1324-1330
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• 2003

A cylindrical cam with a translating roller follower provides to change the rotational motion of the cam to the translation motion of the follower. It's a very useful mechanism in the automation. But, it's very difficult that the shape is defined accurately. This paper proposes a shape design method of the cylindrical cam with a translation roller follower using the relative velocity method$\^$(9,11-13)/ : The relative velocity method calculates the relative velocity of the follower versus the cam at a center of roller, and then determines a contact point by using the geometric relationships and the kinematical constraints. Finally, we present examples in order to prove the accuracy of the proposed methods.

• Tribology and Lubricants
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• 제16권4호
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• pp.289-294
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• 2000

This paper present the contact stresses, which considers the shear stress at the cam and follower interface in the direct acting type valve train system of a high speed engine. To determine the contact condition, the normal contact forces are calculated by using the lumped mass dynamic modeling. The line contact is considered between the cam and follower interface. The variations of dynamic stresses are presented as a function of camshaft rotational angle. Also the effects of various design parameters are investigated.

• 한국생산제조학회지
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• 제19권6호
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• pp.739-745
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• 2010

The roller gear cam can control the rotational follower periodically by attaching several roller on the circumstance of follower shaft and it is widely used in non-backlash and precise actuating mechanism such as index table or ATC of machine tools. For machining the roller gear cam, 5 axis CNC machine tool is used and the geometric principle of CAM mechanism must be adopted to generate the NC-code and to develop the special CAD/CAM software because there is not commercial CAM system to machine the roller gear cam. The maker of the specially developed software in domestic user is generally from Japan or Taiwan. However these softwares do not reflect the post processing technique for finish machining in the module. Also, there is some limitation for further new application of itself and it needs higher costs for further application. In this study, the CAD/CAM software to overcome these problem was developed. And its reliability was verified by applying it in 5-axis CNC machining. Finally, the experimental result conducted in the 5-axis machining show good consistency in the movement of follower along the flute and in its Size.

• 연구논문집
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• 통권33호
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• pp.89-97
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• 2003

A barrel cam is used as a very important part of an index drive unit. The index drive unit must have an intermittent-rotational motion. The barrel typed cam and roller gear mechanism has the advantages of high reliability to perform a prescribed motion of a follower. This paper proposes a new method for the shape design of the barrel cam and also a CAD program is developed by using the proposed method. As defined in this paper, the relative velocity method for the shape design calculates the relative velocity of the follower versus cam at a center of roller, and then detemines a contact point by using the geometric relationships and the kinematic constraints, where the direction of the relative velocity must be parallel to a common tangential line at the contact point of two independent bodies, i.e. the cam and the follower. Then, the shape of the cam is defined by the coordinate transformation of the trace of the contact points. This paper presents shape design of the barrel cam in order to prove the accuracy of the proposed methods

• 한국정밀공학회지
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• 제19권8호
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• pp.47-54
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• 2002

A barrel cam is used as a very important part of an index drive unit. The index drive unit must have an intermittent-rotational motion. The barrel typed cam and roller gear mechanism has the advantages of high reliability to perform a prescribed motion of a follower. This paper proposes a new method for the shape design of the barrel cam and also a CAD program is developed by using the proposed method. As defined in this paper, the relative velocity method for the shape design calculates the relative velocity of the follower versus cam at a center of roller, and then determines a contact point by using the geometric relationships and the kinematic constraints, where the direction of the relative velocity must be parallel to a common tangential line at the contact point of two independent bodies, i.e. the cam and the follower Then, the shape of the cam is defined by the coordinate transformation of the trace of the contact points. This paper presents two examples for the shape design of the barrel cam in order to prove the accuracy of the proposed methods.

• Journal of Yeungnam Medical Science
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• 제20권2호
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• pp.160-168
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• 2003

요추부 척추에 기구를 시술한 유한요소 복합체 모델을 이용하여 제 4-5 요추간판에 대한 해석을 수행한 결과, 근육의 작용을 케이블과 케이블 가이드로써 단순화 모사한 follower 하중에서 수직하중인 경우보다 높은 압축력을 나타내어 더욱 안정함을 보였고 불안정성의 원인이 되는 전단력과 굽힘모멘트의 발생은 미미하였다. 장분절 고정에 의한 인접 분절에 전단력이 증가됨을 실험적으로 보였는데, 이는 장분절 고정이 퇴행성 변화 촉진에 기여할 것으로 추정된다.

• Structural Engineering and Mechanics
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• 제54권3호
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• pp.433-451
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• 2015

This paper focuses on large deflection static behavior of edge cracked simple supported beams subjected to a non-follower transversal point load at the midpoint of the beam by using the total Lagrangian Timoshenko beam element approximation. The cross section of the beam is circular. The cracked beam is modeled as an assembly of two sub-beams connected through a massless elastic rotational spring. It is known that large deflection problems are geometrically nonlinear problems. The considered highly nonlinear problem is solved considering full geometric non-linearity by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. There is no restriction on the magnitudes of deflections and rotations in contradistinction to von-Karman strain displacement relations of the beam. The beams considered in numerical examples are made of Aluminum. In the study, the effects of the location of crack and the depth of the crack on the non-linear static response of the beam are investigated in detail. The relationships between deflections, end rotational angles, end constraint forces, deflection configuration, Cauchy stresses of the edge-cracked beams and load rising are illustrated in detail in nonlinear case. Also, the difference between the geometrically linear and nonlinear analysis of edge-cracked beam is investigated in detail.