A parametric design and simulation system for globoidal indexing cam mechanisms

The paper researched on the globoidal indexing cam, and established the parameter designsystem based on VC++ ObjectOriented method and ProE secondary development, which can guideuser to complete the data input with the friendly interface. It made synthesis of the mechanism andgeneration of the cam profile automatic. The system is proximate, easy to operate and adjust. Thenthe assembly model was built under the circumstance of ProENGINEER directly. And meanwhilethe movement of the mechanism was simulated and the interference was checked so that we cancertify the design. This is a new method for the mechanisms deep research and extensive application.

A Parametric Design and Simulation System for

Globoidal Indexing Cam Mechanisms

1 School of Mechanical and Electric Engineering, Tianjin Polytechnic University, Tianjin, 300160, China a

gonghuiTJPU@126.com, byinmingfu@163.com

Keywords: globoidal indexing cam; Pro/ENGINEER secondary development; parameter design;

simulation

Abstract The paper researched on the globoidal indexing cam, and established the parameter design

system based on VC++ Object-Oriented method and Pro/E secondary development, which can guide user to complete the data input with the friendly interface It made synthesis of the mechanism and generation of the cam profile automatic The system is proximate, easy to operate and adjust Then the assembly model was built under the circumstance of Pro/ENGINEER directly And meanwhile the movement of the mechanism was simulated and the interference was checked so that we can certify the design This is a new method for the mechanism's deep research and extensive application

Introduction

Globoidal indexing cam (Fig.1) is a kind of intermittent indexing step transmission mechanism used between two vertical axis and has been widely used in the packaging machinery, machine tool industry, food processing and other fields for its good performance and unique structure

Fig 1 Globoidal indexing cam mechanism

However, the agency's design theory and manufacturing technology is relatively complex, and the study of it in China started relatively late, some of the key theoretical analysis were still in further investigation So the research of globoidal indexing cam has important practical significance for the technological advances of mechanical automation

Profile Equation

Based on the analysis of space mesh theory, and according to the coordinate transformation, the profile equation[1]of globoid indexing cam can be expressed as:











+

=

+

− +

−

=

−

−

−

=

φ φ

θ θ

θ φ θ

φ

θ θ

θ φ θ

φ

cos sin

sin cos

sin sin sin

cos

cos sin

cos sin cos

cos

2 2

1

2 2

2

1

2 2

2

1

y px

z

C z

py x

y

C z

py x

x

All rights reserved No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans

where x1,y1,z1are three-dimensional coordinates of the cylindrical roller surface conjugate contact point in the coordinate system S2 θis rotational angle of cam, andθ equals zero at the beginning

of the indexing, facing arrow to see z′ -axis, counter-clockwise is positive, 0 0≤θ ≤θf,θfis cam indexing rotational angle In the above equation:φ =φ0 + pφi, in whichφ0is roller start position angle and φi is roller angular displacement

Parametric System

System Design In order to improve the design automation of the globoidal indexing cam mechanism

, the design process will be encapsulated within the system (object-oriented approach)and only the user interactive interface is displayed to user, from which the user can input or modify geometry parameters and motion parameters of the indexing cam, then the data will be passed to the Pro/ENGINEER database through the design system to generate a three-dimensional model Design

of the system is shown in Fig.2, in which HCI(Human-Computer Interaction) is marked by dashed frame

Fig 2 System design

System Work Flow Once system design is determined, the various functions of the system will

be initially set, in order to achieve these functions, the system design process needs detailed planning Specific design flow chart is shown in Fig 3

Parametric Dialogue Design

MFC (Microsoft Foundation Class) is used to design the dialog interface[2~4] to achieve the parametric design of indexing cam mechanism MFC is an important software resources of VC+ + program, and

it provides powerful support for windows applications Using MFC can take advantage of advanced technology tools provided by VC+ + development environment to realize the visual design of the program interface

Fig 3 System work flow chart

Fig 4 Turntable parameter input dialog

Fig 5 Hub parameter input dialog

Fig 6 Globodial indexing cam basic parameter dialog

Fig 7 Globoidal indexing cam secondary parameter dialog Parameters in each parameter input dialog can be modified for model regeneration so as to meet the design requirements.Furthermore, when a parameter in Fig.7 is set, the range of the next parameter value can be determined to facilitate the selection of specific parameter value After all the parameters have been identified , the arc data can be output with format as follows:

Open Arclength

Begin Section ! 1

Begin Curve ! 1

1 -105.061638 -0.000003 7.227856

2 -103.213882 -0.000003 7.993223

……

16 -77.345253 -0.000003 18.708359

Begin Section ! 2

Begin Curve ! 1

1 -104.996208 3.716893 7.231058

2 -103.149529 3.654662 7.996508

……

Begin Section ! 61

Begin Curve ! 1

1 66.060722 114.420525 58.100292

2 65.678040 113.757698 59.948051

……

16 60.320473 104.478119 85.816673

Read in data from Pro / E and the resulting surface is shown in Fig 8 and the first work surface generated after identified can be seen in Fig 9

Fig 8 Surface generated by the data

Fig 9 Surface generated after identifed Fig 10 Four surfaces generate

After a series of repair in the Pro/E, it is ultimately assembled with the generated hub to get a complete globoidal indexing cam, shown in Fig 11

Then through the turntable parametric input dialog to generate a specified dial shown in Fig 12:

Fig 11 The final model of globoidal

indexing cam

Fig 12 The turntable model generated

by dialog

Simulation Globoid Indexing Cam

Enter the assembly module and assemble the designed globoid indexing cam with the turntable, then define the institution to motivate, the simulation process is shown in Fig 13:

(a) Indexing begin (b) Indexing end (c) Stopover

Fig 13 Simulation

Interference Detection

Interference detection can be carried out both in the process of assembly and simulation, if there is interference, interference area will be displayed at high brightness, interference detection in the simulation process is shown as follows:

Fig 14 Intervention test during the simulation

Conclusion

In this paper, a practical and visual virtual design system for indexing cam mechanism was established, which gives the user-friendly parameter input dialog to complete the automatic synthesis

of institutional parameters and automatic generation of cam profile With virtues of intuitive, easy operation and adjustment,the system provides a new method for wide application of the agency

References:

[1] Yuan Enhui, Zhang Chun, Dong Jixian: Journal of Northwest Institute of Light Industry Vol.19 (2001), No.1, pp.41-43

[2] PTC: Pro / TOOLKIT user's guide (PTC, 2004)

[3] Li Shiguo: Pro / TOOLKIT programming (China Mechine Press Beijing 2003)

[4] II Long Zhen studio: Pro/TOOLKIT Wildfire 2.0 plug-in design (Publishing House of Electronics Industry Beijing 2005)

A Parametric Design and Simulation System for Globoidal Indexing Cam Mechanisms

10.4028/www.scientific.net/AMM.66-68.916