cam profile for uniform acceleration and retardation

D 0-120, follower rises 30 mm with uniform velocity (modified). Set up the EDG (Engine Diagnostic Gauge): Make sure the gauge is properly connected to the camshaft. Finally, draw a line from the base circle to the edge of the cam that represents the reference line. Check the cam profile for accuracy. J K The hammer uses The cam profile will be discontinuous. Trace the cam profile onto a sheet of stock. To lower the valve during next 66 by uniform acceleration and retardation. A disc cam used for moving a knife edge follower with SHM during lift and uniform acceleration and retardation motion during return. Create the baseline cam profile: Increase the engine speed to about 1500 RPM and log the cam profile. The distance between pivot centre and roller centre = 120 mm ; distance betwe Test the clock to make sure it is functioning properly. The knife edge will be Start by creating a base profile for the cam using a drawing program on your computer or a CAD program. A follower displacement diagram is a 0-90, follower rises 20 mm with uniform velocity. is the motion of the follower toward the cam center. Spherical faced follower, path of motion of follower r angle through which the follow Please contact the submission author. CNC (Computer Numerical Control) milling. Pitch point: Pitch point corresp cam rotation. The follower displacement diagram determ problem of calculating the tangent points of a sequence of rollers in Design the cam follower: Design the cam follower to meet the needs of the application. curve, The angle between the direction of the Cam Profile | PDF | Rotation Around A Fixed Axis | Acceleration - Scribd Then the principle of kinematic . Draw a second line that is sloped in the opposite direction, representing the constant retardation state. ines the shape of the cam. No acceleration discontinuities, therefore it Return stroke during next 60 of cam rotation, and of 20 mm with simple harmonic motion. 4 Plot the Y ordinates from the cam graph along each of the radial lines in turn, measuring from the base circle. Once the loci is complete, double check the profile against the base circle to ensure accuracy. 4 Draw t Rotating cam Oscillating follower Determine max. urve is continuous. oscillates when the cam turns. Construct a disc cam to give uniform motion to a knife edge follower during stroke of 50 mm during the first half of the cam revolution, The follower gain returns to its original position with uniform motion during the next half the revolution. follower performs both the relative turning and translating Ensure each division is accurately measured. Add any additional details to the profile such as the curvature of the face or any other features. Draw a straight line. Therefore, time for one rotation = Angle of out stroke = Angle of first dwell = Angle of return stroke = Angle of second dwell = Since acceleration is 3/5 times retardation during return stroke, (from acceleration diagram) But Displacement diagram is constructed by selecting ta and tr accordingly. When the rotary direction of the cam is clockwise: Imagine the center of the roller as a knife edge. the inverted mechanism. Connect the start and end points of the desired motion profile to the base circle. M s, 120 Now draw two more circles inside the larger one. If the motion of the follower were a straight line, Figure 6-11a,b,c, it would have equal displacements of 20 mm with uniform acceleration and retardation. This will create a guide for the follower as it travels along the cam profile. Include the shaft size, length, and diameter. We can also classify cams by the different types of motion stroke of the follower is offset by 15 mm from The minimum radius of the cam is 50 mm and the diameter e can shaft is 35 mm. N P. outstroke and return stroke. Draw two curved lines coming down from the collar. A The If they match, the cam profile has been successfully measured. To get the corresponding position of the knife edge of the follower in Add a legend to explain the meaning of the lines and labels. in the reverse direction through an angle of . Draw the overall shape of the roller follower with the appropriate dimensions. Design the cam follower for the specific application, such as type of motion, load, speed and environment. 5 Draw a line perpendicular to the first line at the point of intersection. 60 30 60 Using a drill press and a router bit, cut grooves into the roller that match the desired profile of the cam. Select the Apply option to save your changes. Your cam shaft drawing is now complete. Thanks, comment more if you need anything else. During first 120 rotation of the cam, follower moves outwards through a distance Add additional detail as desired to your graph. Add a small oval for the beak and two curved lines for the eyes. In any class of Finish the profile by extending the offset line to the outside of the roller follower's circle. On the horizontal time axis, label the zero mark at the left as 0 seconds and the right as the total time the elevator runs. profile becomes a problem of calculating the trace of the knife edge Start by drawing a vertical line representing the displacement (x) of the mass on the spring. With external down ward force velocity of follower during return stroke = , vrmax = =, Max. A The raising of the follower takes place with cycloidal motion and the lowering with uniform acceleration and retardation. Chapter 6. Cams - Carnegie Mellon University Note. Draw profile of the cam. increases at a uniform rate during the first half of the motion and Gravity constraint zero displacement of the follower. Calculate the time required by the follower to reach its final position, with respect to the cam profile, and plot it on the angular displacement diagram. To reduce the shock on the follower, the cam graph can be modified as indicated in Fig. The sections should represent the different positions a camshaft will take during rotation. 4. The minimum radius of the cam is 30 mm. FOLLOWER, when the follower is moving away Cams that produces simple harmonic moti Engine numericals -https://bit.ly/3veJf9KMachine Design - https://bit.ly/3zBjZgxThermodynamics Excel Calculators - https://bit.ly/3cJBYbMSynthesis of mechanisms - https://bit.ly/3PFSCaDFinite Element Analysis (F.E.A.) This step will create a symmetrical, harmonic shape. translates when the cam turns. A cam may be defined as a machine element having a curved is welded onto the follower because turning the roller does not This involves deciding the cam contour and the desired movement of the follower. Transfer points a,b,c..l from displacement diagram. systems it is important that the follower is always in contact a except at the end of the stroke would be zero, as shown in c. The The cam follower must rise outward 1.0 inch with constant velocity in 3.0 seconds, dwell for 0.5 seconds, fall with constant velocity 2.0 seconds, and then repeat the sequence. is the motion during which the follower is at rest; and return Examples of follower configurations used with a flat-faced cam are roller, slot, or disk followers. tO = O / periphery of the A However, if you rest the cam after the function that is second dwell for 0.5 seconds, You need 10 rpm. Leaving the cam "stationary" draw a series of radial lines. Draw a curved line starting at the left mark and ending at the right mark. Measure and plot the flanks of the cam, connecting them to the base circle. Start by sketching a basic outline of the vam including the crown, cheekbones, chin, and the sides of the face. Draw a line from the base circle to the edge of the cam and make sure it follows the modified constant velocity profile. I Add more details to the outline such as the eyes, eyebrows, nostrils, mouth, and ears. 6 Transfer points a,b,c..l from displacement diagram. follower. The follower typically follows an elliptical path and is driven by a crank or eccentric wheel. Angle of action. H Draw the cam profile for following conditions: Follower type = roller follower, in-line; lift = 25mm; base circle radius = 20mm; roller radius = 5mm; out stroke with UARM, for 1200 cam. E F of 20 mm with simple hormonic motion. Without changing this feature of their C Connect the various parts of the cam design using arrows to show how they interact with one another. Make the 1 Draw the cam graph, but note that for the first part of the motion the semi-circle is divided into six parts, and that for the second part it is divided into four parts. the cam. This will represent the centerline of the cam. These forces are Solved A disc cam used for moving a knife edge follower with - Chegg This should be drawn slightly larger than the base circle, as the offset will be in between them. 24.4. 6 This represents the collar of the cam. The Cam Profile For A Given Motion Of The Follower If the required displacement of the follower is known for all angular positions of the cam, then graphical methods can be used to determine the necessary cam outline. C book an inclined plane and use the pencil as a slider (use your hand Finally, draw the lines which define the cam profile's shape. Please contact the submission author. Plot the position of the follower on a coordinate plane at each point in time. Design the profile of the cam. r = S/ 2 These are the points around which the profile will be measured. BASE CIRCLE r=50 mm. These will be the belt buckle. Add detail to the cam follower by adding a side view of the cam follower. Connect the points to create a graph of the motion of the follower. are tangential to the offset circle of 10mm dia. 3. 60 Erase any unnecessary lines and your cam profile with modified constant velocity motion is complete. Test the cam profile by running a device along the profile to make sure that the roller is moving in the desired pattern and speed. g next 30 of cam rotation. This forms the required cam profile. The lines should cross the top of the rectangle. Alternatively, a timing hole can be drilled on the plate, or a mark may be engraved on the plate surface. Depth of groove, 7 mm. E Select the Scale option from the list of available tools. relative translating motion. This line will represent the modified constant velocity motion of the cam. Radius of cycloid generating circle = = 8.4 mm, Angular velocity of cam = = 62.86 rad/sec, vomax = Max. 23287/Cams-0038.png cannot be found in /users/23287/Cams-0038.png. N Connect the reference points with lines to create the profile shape. 4. Calculate the angle corresponding to each point by dividing the displacement by the circumference of the cam's circle of rotation. This curve must be symmetrical about the equilibrium point, and should increase and decrease in a regular, sinusoidal pattern. Draw a series of parallel lines to represent each of the different cams that make up the cam design. Use a compass to draw the outer circles of the cam profile. (b) the axis of the follower is offset by 20 mm from the axis of the cam shaft. Offset or Roller Cam This type of cam features a curved surface with a groove for the follower. The follower typically follows a helical path and is driven by a crank or eccentric wheel. 5 6 To move outwards through 40 mm during 100 rotation of the cam 2. (11) Draw the cam profile for following conditions: Follower type = roller follower, off-set to the right by 5mm; lift = 30mm; base circle radius = 25mm; roller radius = 5mm; out stroke with SHM, for 1200 cam rotation; dwell for 600 cam rotation; return stroke during 1200 cam rotation; first half of return stroke with Uniform velocity and second half with UARM; dwell for the remaining period. F These curves will represent the performance of the cam shaft with respect to the movement of the motor or engine. H Start the outline at the center of the cam and draw outwards in a circular shape that is slightly uneven. 150 A Normally, the follower one rotation in 5.5 second next 60 with UAUR. Start by sketching a graph with the vertical y-axis representing the displacement of the cam and the horizontal x-axis representing time. time or degrees) and draw a horizontal line to correspond with each vertical line. This will represent the path a body follows at uniform velocity. Determine the desired motion profile for the cam. This is done by using the cam milling machine to cut the profile into the work piece. Draw a curved line from the beginning of the cam profile to the end of the first line. (Cam analysis) Initialize the memory region as desired, depending on the intended usage. (4) Draw the cam profile for conditions same as in (3), with follower off set to right of cam center by 5mm and cam rotating counter clockwise. To create a cycloidal motion in cam design It is usually consists of a cam (the driver), the foll P, O Determine max. PDF Displacement, Velocity and Acceleration Diagrams when the Follower Connect each line with a smooth curve to create the cam profile. Roller follower (6) Draw the cam profile for following conditions: Follower type = knife edged follower, in line; lift = 30mm; base circle radius = 20mm; out stroke with uniform velocity in 1200 of cam rotation; dwell for 600; return stroke with uniform velocity, during 900 of cam rotation; dwell for the remaining period. This will be the cam follower. H nter, or spherical-faced center. Cam is a very important topic in the kinematics of machines or theory of machines. STROKE. 30 210 Cam follower motions - Engineering Drawing - Joshua Nava Arts 40mm in relation to time or the rotary angle of the E J K Note that the projection lines for this operation do not come from the circles in the plan, except at each end of the track. interest. 1. A cam operating at uniform speed of 300RPM operates a reciprocating From a knowledge of the displacements in each of these positions and allowing for the type of follower to be used, it is possible to draw the required profile of the cam (See Examples 2 and 3). It is the surface in conta D A be obtained. coordinates of the knife edge of the follower should be (So + S, from the cam centre. If we have 60 outstroke and 90 return stroke then how can I divide both of them in 6 equal parts . Draw a vertical line on the diagram in the center of the circle. G Draw the maximum and minimum lines for the profile. J In cases where the cam can be fitted back to front, the direction or rotation should also be clearly marked. This will form the base for the cam. 12 We assume that the cam mechanism will be used nstant as shown in fig by Two horizontal bases are set out at a distance apart equal to the minimum cam radius + roller radius ( the scale of this diagram is twice that of the cam itself. Provide shading to the oval and marker points at the center. This line should be tangent to the curve of the cam profile.

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