Tài liệu Valve Cam Mechanism docx

Valve Cam Mechanism 1 ME-430 INTRODUCTION TO COMPUTER AIDED DESIGN Valve Cam Mechanism Pro/ENGINEER Wildfire 3.0 Dr. Herli Surjanhata There are 6 parts that will be used in this mechanism analysis: • shaft_mount.prt — the ground body. • camshaft.prt (rotating body) • rocker.prt (oscillating body) 2 • valve_guide.prt (ground body) • valve.prt (sliding body) • rocker_shaft.prt (rotating body) PART: SHAFT_MOUNT.PRT 3 PART: CAMSHAFT.PRT 4 PART: ROCKER.PRT PART: ROCKER_SHAFT.PRT 5 PART: VALVE.PRT 6 PART: VALVE_GUIDE.PRT 7 CREATE AN ASSEMBLY – rocker_arm.asm Create a new assembly called rocker_arm. Uncheck Use default template. The New File Options dialog box appears. 8 Select System of Units of mmns_asm_design. Under Parameters, fill DESCRIPTION and MODEL BY with Rocker Arm Assembly and your name. OK. The assembly should have default datum planes – ASM_FRONT, ASM_RIGHT, and ASM_TOP. 9 Click to open rocker_shaft.prt Select to assemble the rocker_shaft.prt at default location. Click to finish the assembly operation. Click and open rocker.prt, Keep default setup for assembly. Apply the following constraints between rocker_shaft and rocker – see below. • Align the axis of the rocker.prt with the axis of the of rocker_shaft.prt Align constraint. • Align OFFSET the FRONT datum plane of the rocker.prt with the ASM_FRONT datum plane of the rocker_arm.asm assembly Align constraint. The offset distance is 25 mm. [...]... Save the assembly The rocker_arm.asm will be sub-assembly for total valve_ cam assembly 10 CREATE AN ASSEMBLY – valve_ cam. asm Create a new assembly called valve_ cam Uncheck Use default template The New File Options dialog box appears 11 Select System of Units of mmns_asm_design Under Parameters, fill DESCRIPTION and MODEL BY with Valve Cam Mechanism and your name OK The assembly should have default datum... constraint Pick and pick the camshaft Try to move the valve up and down to test the slider connection 25 CREATING A CAM- FOLLOWER CONNECTION AND SPRING CREATING A CAM- FOLLOWER CONNECTION From Application pull down menu select, Mechanism - Mechanism Design begins 26 Click The Cam- Follower Connection Definition dialog box opens On the Cam1 tab, select the Autoselect check box Mechanism Design completes... OK to accept and exit the CamFollower Connections Definition dialog box Mechanism Design adds a cam- follower icon to your mechanism Click (Point Drag) and rotate camshaft.prt Note that the motion of the follower subassembly is now linked to the motion of the cam Click The Cam- Follower Connection Definition dialog box opens 28 On the Cam1 tab, keep the Autoselect un-checked Mechanism Design completes... ADTM1 datum plane of the valve_ cam. asm assembly as Translation constraint 22 Pick and pick the camshaft Try to rotate the camshaft about the shaft_mount Open valve_ guide.prt and assemble the valve_ guide to the assembly with the following constraints: • Align the TOP datum plane of the valve_ guide.prt with the inclined ADTM5 datum plane of the assembly 23 • Align the axis A_2 of the valve_ guide.prt with... the valve and valve_ guide Open valve. prt in the assembly 24 From the list, select slider for creating a slider connection Apply the following constraints for slider connection between valve and valve_ guide – see below • Align the axis A_2 of the valve. prt with the AA_1 axis of the assembly as Axis alignment constraint • Align the RIGHT datum plane of the valve. prt with the RIGHT datum plane of the valve_ guide.prt... to your mechanism 29 Verify the motion of the mechanism by selecting parts will also move Rotate the camshaft and all other 30 CREATING A SPRING A point-to-point spring between valve_ guide and valve will be added Click (Define Springs) The Spring Definition dialog box opens 31 Select Point-to-Point under Reference Type, and use the arrow button to select PNT0 on valve_ guide.prt and PNT0 on valve. prt... automatically computed Note that U is the unstretched spring length Click OK to accept the definition Mechanism Design adds a spring icon to valve cam mechanism 32 CREATING A SERVO MOTOR On the MECHANISM Model Tree, under CONNECTIONS -> JOINTS, expand the second connection e.g Connection_8 (VALVE_ CAM) by clicking the plus sign (see figure) Highlight ROTATION AXIS, right-click, and select Servo Motor... to define a cam Pick the top flat surface of the valve For the Front Reference, pick datum point PNT0, and for Back Reference, pick datum point PNT1 Select the Cam2 tab Keep the Autoselect un-checked Use the arrow button to select the curved surface on rocker.prt – see figure below OK Click OK to accept and exit the Cam- Follower Connections Definition dialog box Mechanism Design adds a cam- follower... connection for the camshaft and shaft_mount Open camshaft.prt in the assembly From the list, select Pin for creating a pin connection Apply the following constraints for pin connection between camshaft and shaft_mount – see below • Align the axis A_5 of the camshaft.prt with the axis A_4 of the bottom hole of shaft_mount.prt as Axis alignment constraint • Align the FRONT datum plane of the camshaft.prt with... Mechanism Design completes the selection of a set of surfaces after you select enough surfaces to define a cam in the Use the arrow button Surfaces/Curves area to select the curved surface on camshaft.prt Note: Use Right-Mouse-Button pop-up menu Pick From List to pick the needed surfaces OK 27 Select the Cam2 tab Keep the Autoselect un-checked Use the arrow button to select the curved surface on rocker.prt . Valve Cam Mechanism 1 ME-430 INTRODUCTION TO COMPUTER AIDED DESIGN Valve Cam Mechanism Pro/ENGINEER Wildfire 3.0 Dr will be sub-assembly for total valve_ cam assembly. 11 CREATE AN ASSEMBLY – valve_ cam. asm Create a new assembly called valve_ cam. Uncheck Use default template.