• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.1
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• pp.110-122
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• 1996

The objective of this study is to understand the dynamic characterictics of OHV type valve trains and to design and optimal cam profile which will improve engine performance. A numerical model for valve train dynamics is presented, which aims at both accuracy and computational efficiency. The lumped mass model and distributed parameter model were used to describe the valve train dynamics. Nonlinear characterictics in the valve spring behavior were included in the model. Comprehensive experiments were carried out concerning the valve train dynamics, and the model was tuned based on the test results. The dynamic model was used in designing an optimal cam profile. Because the objective function has many local minima, a conventional local optimizer cannot be used to find an optimal solution. A modified adaptive random search method is successfully employed to solve the problem. Cam lobe area could be increased up to 7.3% without any penalties in kinematic and dynamic behaviors of the valve train.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.11
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• pp.2049-2058
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• 1992

In this work, a 6 degree of freedom lumped mass model is constructed for an OHC-type cam valve train analysis, and the model is verified experimentally. Using the verified model, an optimum cam profile is designed to minimize the maximum contact force between cam and follower under the constraints such as cam lift and cam event angle. The designed cam was carefully machined and tested experimentally. As operating the designed cam shaft on the test rig, the valve motion was precisely measured with laser displacement meter and the contact force was indirectly monitored by measuring strain at a certain point of the finger follower. Judging from the model simulation and experiment results, the maximum contact force can be reduced as much as more than 16.7 percent under maintaining the original valve flow area by adopting the optimum cam profile.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.283-289
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• 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.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.1
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• pp.106-112
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• 2008

In this paper, It does the profile measurement of the cam of diesel engine SOHC of the actual object. It uses the measurement of run-out method. This method is that the surface of the object is measured by the sensor when the object rotate, and calculated and displayed by the computer the signal which acquired by sensor. When we acquire the signals, we have two error because of motion and contacting between cam and probe. In this paper, we compensate the motion error while simply liner equation. And we have a solution that we change the figure of probe when we have a contacting error. We compared the data measuring on developed automatic cam profile measuring system with the data measured on CMM.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.112-119
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• 2009

Cam mechanisms are one of the most popular devices for generating irregular motion and are widely used in many automatic equipments, such as textile machinery, internal combustion engines and other automatic devices. In order to obtain the positive motion of follower by rotating cam, its shape should be correctly designed and manufactured. However, complex engineering tasks are required in a design and manufacturing of cams. And also, the manufacturing of general cam is demanded high costs. For the designing of cam, it must be decided that what kind of motion has to be transmitted to follower before selecting the curve of cam and designing profile of cam. However, even though the exact profile of cam is designed at the progress of design, if it doesn't have precision at the manufacturing progress, it's impossible to get expected result. We will develop cam simulation apparatus for measuring cam curve and get profile data before analyzing an error through comparison with design data of cam.

• Journal of Power System Engineering
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• v.1 no.1
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• pp.42-51
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• 1997

In this study, in order to investigate the influence of cam profile on the injection rate, the characteristics of injection in PLN (pump - line - nozzle) diesel injection system were simulated. Six types of the profile of fuel cam were used for simulation. The maximum injection pressure and maximum injection rate of initial and end phase were analyzed to demonstrate the characteristics of injection. The mathematical model of the injection system and the computation results were verified by experimental results. Simulation results showed that the maximum injection pressure, maximum injection rate, injection quantity and pressure drop in the end phase were proportional to the velocity of fuel cam during the effective stroke.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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• pp.129-140
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• 1998

A numerical method is proposed to optimize automotive cam profiles. An acceleration curve of a cam follower motion is described by Hermite spline curves. Because of the intrinsic characteristics of the Hermite curve, it is possible to design an acceleration curve with arbitrary shape. Design variables in the optimization problem are location of control points which define the acceleration curve. Objective function includes dynamic performances as well as kinematic properties of a valve train. Similar optimization procedure was also performed using Polydyne cam profile synthesis method. Optimized profiles using the Hermite curve are proved to be superior to those using the Polydyne method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1231-1232
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• 2010

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.204-209
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• 2003

Cam mechanisms are one of the most popular devices for generating intermittent motion and are widely used in many areas. Also, as being interested in research of precision field, cam mechanism is required high accuracy and continuity, In. In this paper, the cam mechanism of filament automatic assembly machine design for precision motion is proposed. The modelling of a cam mechanism, cam profile functions, and the design of the cam considering the precision positioning of the cam mechanism is studied. And, simulation of designed cam mechanism had been carried out dynamic analysis.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.5
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• pp.44-50
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• 2006

Cam mechanisms are one of the most popular devices for generating irregular motion and are widely used in many automatic equipments, such as textile machinery, internal combustion engines and other automatic devices. In order to obtain the positive motion of follower by rotating cam, its shape should be correctly designed and manufactured. In present paper, a CAD/CAM system is developed for shape design of disk cams using relative velocity method and NC code generation using the biarc curve interpolation. And, a disk cam is successfully manufactured by the developed CAD/CAM system. Thus, it is shown that the developed CAD/CAM system can be used for high precision cam profile CNC grinding machine.