Fig. 7. endstream endobj 511 0 obj<>/W[1 1 1]/Type/XRef/Index[60 401]>>stream 220-360°, follower falls 30 mm with uniform velocity (modified). 30 mm diameter camshaft. Draw another circle of radius equal to the distance between cam center and follower pivot point. 0000088979 00000 n 3A�H���V�?f�g�u�$K�9Fy �{#Q�-��dK���*�ޔ�����t���6��\ke���(�?e^���\���K�@@=V�ڗb'���7�T�y����g�n�%y㐡�e��;��u���ۚ���؈H��y�1�Kn���X��p��}yϧ ���S@��%��vM�;��Le[��Wd ȇܭ�����%�l�>�\�s��Lc��v�K��s5�`d��+���v2z��pɢ=~%A����Ys�>K7'{,�e�͝�_s����YB���|t��4��A0ݻ�\}��r�y$�/ӌ�#�����ц�S�`ߏ�����9| Least radius of cam, 30 mm. Cam Segments. https://www.comsol.com/blogs/how-to-model-a-cam-follower-mechanism 240-360°, follower falls 30 mm with simple harmonic motion. Using the cam graph as the centre line for each position of the roller, draw 14 mm diameter circles as shown. The uniform-retardation parabola is constructed in a similar manner, but in the reverse position. Plot the depth of the track in the front elevation from the end elevation, as shown. 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. Different types of basic motions such as linear, simple harmonic, single parabolic, double parabolic and cycloidal for the heald shaft during its lifting and lowering movement have been 3. 240-330°, follower falls 49 mm with uniform velocity. 5.5(a) shows the particle paths for a flush ratio N FL of unity, with integration mesh superimposed. 1 Set out the cylinder blank and the end elevation as shown. 0000009149 00000 n 24.2. Motion of the Follower • The follower, during its travel, may have one of the following motions. 0000007156 00000 n Given that e is the amplitude, θ is the angle θ = ω t and ω is the angular velocity. Even there may be situation, where a part of the follower motion is of one type and rest of the motion is of another types. The tangents represent the face of the flat follower in each position. Radial lines are drawn from the start position to each of the follower division lines, and the parabola is obtained by drawing a line through successive intersections. The follower dwells during next 30° of ca m rotation. It is required to set out the profile of a cam to give the following motion to the reciprocating follower with a flat mushroom contact surface: (i) Follower to have a stroke of 20 mm during 120°of cam rotation, (ii) Follower to dwell for 30°of cam rotation, (iii) Follower to return to its initial position during 120° of cam rotation, (iv) Follower to dwell for remaining 90° of cam rotation. Mark the camshaft angles in the anticlockwise direction. 20 mm diameter roller follower set 20 mm to the right of the centre line for the camshaft. 3 Draw radial lines 30° apart from the cam centre, and number them in the reverse direction to the cam rotation. Follower**:** With the rotation of the cam, the follower (the shaft with the roller at bottom in the above picture) gets oscillated or translated according to the profile of the cam. How To Draw Animals Using The Lutz Method, Development of patterns from sheet materials, Virtual Pose Series Features Figure Models In Artistic Poses, The Mystery behind Dividend Yield Investing. Tracer Point The point at the knife edge of a follower, or the center of a roller, or the center of a spherical face. 0000011330 00000 n the nearest the follower approaches to the centre of rotation. Specifications of the cam: Base circle radius of the cam: 85. 0000023927 00000 n 461 0 obj<> endobj 180-240°, dwell period. 0000011685 00000 n 0000009101 00000 n This motion is used where the follower is required to rise or fall with uniform acceleration, that is, it's velocity is changing at a constant rate. 5 Draw the best curve through the points to give the required cam profile. 24.4. Pressure angle (ɸ): The common normal between the roller and the cam profile passing through the roller center and is normal to the cam profile. Uniform acceleration and retardation 4. The graphs for both parts of the motion are parabolic. Cam lift = 40 mm during 90° of cam rotation with simple harmonic motion. Cam Profile The contour of the working surface of the cam. To reduce the shock on the follower, the cam graph can be modified as indicated in Fig. 0000000016 00000 n 0000024153 00000 n Transcribed image text: 1. Cycloidal motion 12/25/2015 Mohammad Suliman Abuhiba, Ph.D., PE 21. 90-150°, follower rises 30 mm with simple harmonic motion. 0000132048 00000 n 12 mm diameter roller follower. Join the plotted points to complete the front elevation. %PDF-1.5 %���� In the illustration given, point P appears to be the greatest distance, and hence the follower will require to be at least R in radius to keep in contact with the cam profile at this point. Outward stroke angle: 65 0. 0-180°, rise 64 mm with simple harmonic motion. Displacement x … 0000007182 00000 n 0000002292 00000 n Plot the track on the surface of the cylinder by projecting the sides of the track in the plan view up to the front elevation. The 24.5 where the graph is a sine curve. 0000001358 00000 n Displacement = ; [d1] Velocity = ; [d2] Acceleration = ; [d3] The construction for the parabola involves dividing the cam-displacement angle into a convenient number of parts, and the follower displacement into the same number of parts. Cam Follower Design Terminologies. 0-120°, follower rises 30 mm with uniform velocity (modified). Let S = Stroke of the follower, θ 0, θ r Angular displacement of the cam during out stroke and return stroke of the follower respectively, in radians, and ω = Angular velocity of the cam in rad/s. 4 Draw a curve on the inside and the outside, tangentially touching the rollers, for the cam track. The X axis has been drawn to scale, where 12 mm represents 30° of shaft rotation. The output of the cam profile, for the motion cu rve being simple harmonic motion, for the giv en specifications of the cam is shown below.. Motion Function f y (z) [ul] Reverse Ratio k r (only for motion Parabolic and Parabolic with linear part) Linear Part k l (only for motion Parabolic with linear part) Motion Start Position l 0 [°; mm, in] Motion End Position l [°; mm, in] Segment Motion Length dl = l - … For example, a follower motion may be combination of simple harmonic motion and constant velocity motion. The equations relating the follower displacement velocity and acceleration to the cam rotation angle are: In figure below the displacement, velocity and acceleration curves are shown. 0000002899 00000 n Despite this deficiency, this profile is popular for cam design in low-speed applications because it is easy to manufacture 8.1 Simple HarmonicMotion 27. 60 120 180 240 300 Shaft angle 12 mm represents 30°. The diameter of the roller is 20 mm and the minimum radius of the cam is 25 mm. The simple harmonic motion is a mathematical function that remain continuous throughout any number of diferentiations. Least distance from follower to cam centre, 30 mm. 0000001846 00000 n 330-360°, dwell period. Alternatively, a timing hole can be drilled on the plate, or a mark may be engraved on the plate surface. Take the line joining cam center and pivot point as reference and draw lines indicating successive angular displacements of cam. 3 From each of the base-circle points, plot the lengths of the Y ordinates. 180-360°, follower moves 70 mm to the left with simple harmonic motion. The construction involves drawing a semi-circle and dividing it into the same number of parts as the cam-displacement angle. The curve is the projection of a circle about the cam rotation axis as shown in the figure. Face cam, rotating clockwise. 0000006684 00000 n 0000089048 00000 n 4 Draw a circle of radius Q, as shown, from the centre of the camshaft to the centre of the roller follower. 0-180°, follower moves 70 mm to the right with simple harmonic motion. Now, according to the different types of motion the displacement equation will differ from case to case. Note that in practice the size of the radius frequently used here varies between one-third and the full lift of the follower for the uniform-velocity part of the graph; the actual value depends on the rate of velocity and the speed of rotation. 0-90°, follower rises 20 mm with uniform velocity. Stroke or lift of the follower: 60. In the previous cases, a spring or some resistance is required to keep the follower in contact with the cam profile at all times. Stroke or lift of the follower: 60. 1 Draw the cam graph as shown. Here, P moves with uniform angular velocity ω p, along a circle of radius r (r = s/2). For a Rise-dwell-fall-dwell (RDFD) cam profile, show that a simple harmonic dis- placement function for the rise motion is an unacceptable design h - COS where 0 is the camshaft angle, h is the total rise, and B is the total angle for the rise interval. It is normally connected with a prime mover, which rotates it. 0000011582 00000 n Second dwell period angle: 95 0 0-180°, rise 64 mm with simple harmonic motion. Radius to remove abrupt change in direction. 20 mm diameter roller follower. Least distance from the roller centre to the camshaft centre line, 50 mm. 240-360°, fall 64 mm with uniform velocity. 24.3 by adding radii to remove the sharp corners. First dwell period angle: 75 0. Motion of the Follower 1. The diameter of the semi-circle is equal to the rise or fall of the follower. 0000007318 00000 n 464 0 obj<>stream endstream endobj 462 0 obj<. Simple harmonic motion curve is widely used since it is simple to design. First dwell period angle: 75 0. Simple harmonic motion 3. 2 Draw a circle (shown as RAD Q) equal to the least radius of the cam plus the radius of the roller, and divide it into 30° divisions. Simple Harmonic motion: The displacement diagram, velocity diagram and acceleration diagram for SHM is shown in fig 1.7. Trigonometric form curves are simple harmonic motion (SHM), which has a cosine acceleration curve, cycloidal which has sine acceleration curve, double harmonic and elliptical and their modified forms. 2 Uniform acceleration and retardation motion is shown in Fig. 3 Simple harmonic motion is shown in Fig. A cam mechanism with the basic curve like g in Figure 6-7g will impart simple harmonic motion to the follower. The velocity diagram at h indicates smooth action. startxref Pitch Curve The path of the tracer point. Divide these into same number of divisions as in the displacement diagram. Where rapid changes in direction occur, or where there is uncertainty regarding the position of the profile, more points can be plotted at 10° or 15° intervals. 0000009528 00000 n 4.9 Displacement, velocity and acceleration diagrams when the follower moves with simple harmonic motion. Prof, DSCE, BLore-78 32 33. 4 Plot the Y ordinates from the cam graph along each of the radial lines in turn, measuring from the base circle. 3 Along each radial line plot the Y ordinates from the graph, and at each point draw a 20 mm circle to represent the roller. 0000002719 00000 n The drawing shows the completed cam together with a section through the vertical centre line. Note that the projection lines for this operation do not come from the circles in the plan, except at each end of the track. Draw a tangent at each of the plotted points, as shown, and draw the best curve to touch the tangents. Fig.5: Simple Harmonic Motion. Cylindrical cam, rotating anticlockwise, operating a roller follower 14 mm diameter. (d) Simple Harmonic Motion: In fig.5, the motion executed by point P l, which is the projection of point P on the vertical diameter is called simple harmonic motion. 0000089385 00000 n 30 60 90 120 150 180 Angular displacement of cam. 0000131852 00000 n 2 Draw a base circle 32 mm radius, and divide into 30° intervals. During next 120° of cam rotation, the follower moves inwards with simple harmonic motion. 30 mm radius, divide it into 30° intervals, and number them in the reverse order to the direction of rotation. Figure 5 3.3 HARMONIC MOTION Simple Harmonic Motion is when the shape of the displacement-time graph is sinusoidal. 461 51 2 To plot the cam, draw a 20 mm diameter circle to represent the bore for the camshaft, and another circle 30 mm radius to represent the base circle, or the least radius of the cam, i.e. Depth of groove, 7 mm. 0000132342 00000 n Camshaft diameter, 20 mm. Base Circle The smallest circle drawn, tangential to … 0000024305 00000 n 2. Simple-harmonic motion is a more appealing approximation to conditions in the Stirling engine than u = constant, and is such an elementary embellishment that it forms the basis for the example: Fig. 6 Draw the best profile for the cam so that the cam touches the rollers tangentially, as in the last example. Outward stroke angle: 65 0. Cam cylinder, 60 mm diameter. Plate cam, rotating anticlockwise. 0000089493 00000 n The x – t graph is shown with the cam profile. 0-180°, follower rises 30 mm with simple harmonic motion. 0000131595 00000 n 0000132022 00000 n Angle between the common normal / contacting force and the follower movement. Plate cam, rotating clockwise. 0000004615 00000 n 210-270°, follower falls 20 mm with uniform acceleration. 0000010123 00000 n %%EOF Flat follower. 0000009369 00000 n 4. The output of the cam profile, for the motion cu rve being simple harmonic motion, for the giv en specifications of the cam is shown below.. Dwell during the remaining 180°. Simple harmonic motion (SHM) 3. Abrupt changes in velocity with high-speed cams result in large accelerations and cause the followers to jerk or chatter. 2 Draw a circle (shown as RAD Q) equal to the least radius of the cam plus the radius of the roller, and divide it into 30° divisions. 2 Draw a 20 mm radius circle, and divide it into 30° divisions as shown. Cam**:** The cam is the driver. 0000007938 00000 n https://learnmech.com/cam-and-follower-types-diagram-parts-working During the next 60° of cam rotation, the follower returns to its original position with simple harmonic motion. Draw a cam profile to drive an oscillating roller follower to the Fig 1.7 Displacement, Velocity and Acceleration diagrams of SHM. Plate cam, rotating anticlockwise. 3 Where the 30° lines touch the circumference of the 20 mm circle, draw tangents at these points. 0000003212 00000 n 0000005480 00000 n This circle is the base circle. Point follower. 0 120 180 240 12 mm represents 30° camshaft angle. Cam Profile for Simple Harmonic Motion Uniform Acceleration/Retardation: Acceleration is the rate of change of velocity with respect to time. The dotted line in the end elevation indicates the depth of the track. 0000132587 00000 n To accomplish the computational plotting of the cam profile, some basic weaves like plain and twill have been chosen with one third dwell period. Least radius of cam, 26 mm. 0000009127 00000 n 1 Draw the cam graph as shown, and modify the curve to remove the sharp corners. 4 Draw the best profile for the cam so that the cam touches the rollers tangentially, as shown. Part of a uniform-velocity cam graph is shown in Fig. Mark the camshaft angles in the anticlockwise direction. Underneath the front elevation, draw a development of the cylindrical cam surface, and on this surface draw the cam graph. This type of motion is not desirable for high speeds. The acceleration, as shown at i, is maximum at the initial position, zero at the mid-position, and negative maximum at the final position. 0000008748 00000 n Exact dimensions are used for the Y axis, where the follower lift is plotted. 120-210°, follower rises 21 mm with uniform retardation. 240-360°, fall 64 mm with uniform velocity. 0000011165 00000 n 0000004121 00000 n 0000002169 00000 n Cam profile by Praveen Chugh About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features © 2020 Google LLC Return stroke angle: 125 0. Camshaft diameter, 30 mm. 4 Check the point of contact between the curve and each tangent and its distance from the radial line. Note that the follower runs in a track in this example. Although the axis of the follower and the face are at 90° in this example, other angles are in common use. 0000089424 00000 n Note. Cam profile: Draw base circle and prime circle. A cam drives a flat reciprocating follower in the following manner : During first 120° rotation of the cam, follower moves outwards through a distance of 20 mm with simple harmonic motion. 1 Draw the graph as shown. Return stroke angle: 125 0. 0000002032 00000 n Design a cam to raise a valve with simple harmonic motion through 50 mm in 1/3 of a revolution, keep if fully raised through 1/12 revolution and to lower it with harmonic motion in 1/6 revolution. 0-120°, follower rises 28 mm with uniform acceleration. Dwell for the next 30°. Note that, although the roller shown is parallel, tapered rollers are often used, since points on the outside of the cylinder travel at a greater linear speed than points at the bottom of the groove, and a parallel roller follower tends to skid. Specifications of the cam: Base circle radius of the cam: 85. Cam Nomenclature 19. 0000004295 00000 n <<84bd6d316314a446a542607b754c2fa7>]>> �A�y���%ѽ�;�U=�j�7rQy�+aR�!kj�� 2 Draw the base circle as before. Draw the profile of the cam when x�bb2a`b``Ń3� ���ţ�1T� � ��] However, this action results in an increase in the average rate of rise or fall of the follower. Divide the end elevation into 30° divisions. 0000003451 00000 n The valve remains closed during the rest of the revolution. Plate cam, rotating clockwise. 270-360°, follower falls 30 mm with uniform retardation. 0000003887 00000 n Least radius of cam, 35. been developed or applied to Cam follower mechanisms, including simple polynomial curves and trigonometric curves. Uniform velocity (UV) 2. 5 From the base circle, mark lengths equal to the lengths of the Y ordinates from the graph, and at each position draw a 20 mm diameter circle for the roller follower. The graph passes through successive intersections as indicated. 0000008625 00000 n 0000004436 00000 n Second dwell period angle: 95 0 The user will require to know where the cam program commences, and the zero can be conveniently established on the same centre line as the shaft keyway. xref 0000005299 00000 n – Uniform velocity – Simple harmonic motion – Uniform acceleration and retardation – Cycloidal motion 1/27/2014 Hareesha N G, Asst. 3 Plot the Y ordinates from the graph, radially from the base circle along each 30° interval line. 1 Uniform velocity This motion is used where the follower is required to rise or fall at a constant speed, and is often referred to as straight-line motion. Camshaft diameter, 20 mm. Since the follower moves with a simple harmonic motion, therefore velocity diagram consists of a sine curve and the acceleration diagram consists of a cosine curve. Draw a circle at each point for the roller follower. 0000011754 00000 n 0000010618 00000 n 0000006090 00000 n 25 mm diameter camshaft. trailer Mark the position of the widest point of contact. https://sites.google.com/view/b-vishwash/kinematics-of-machines/unit-5-cams In cases where the cam can be fitted back to front, the direction or rotation should also be clearly marked. The application of the various motions to different combinations of cams and followers is shown by the following practical example. Draw the cam track with the sides tangential to the rollers. Note also that a flat follower can be used only where the cam profile is always convex.

Gsx Coin Price Prediction 2030, Fiserv Ireland Address, Rapamycin Dog Aging Project, Breaking News In Yuba County Online, Violette _fr Lipstick, Peter Lincoln Focusing, Bobby Meaning In Urdu,