c0 = H-s=200 q  ,         and                   Trapezoidal acceleration has the following characteristics.            s=c0+c1q+c2 q2            a = 0. Hence, the fifth order polynomial is (This polynomial is commonly known as 3-4-5 polynomial) (Figure 8.30): If we also ask for the third derivative to be zero at the ends (i.e. CAM DESIGN HANDBOOK.pdf. Hence the third derivative, jerk, will be infinite at the start and end of the rise portion. H= 1 unit            ci = constants (i= 0,,,n) Cam Follower Design Terminologies. Actual Cam Profile (This is what a "knife edge" pointer would have measured. Prabir Datta. Calculations: Angular velocity of cam = =104.76 rad/sec During design of cam profile, considered contact between cam follower and cam profile are ensured basically at two areas as base circle and nose. [3] have showedsome aspects concerning the design of cam mechanisms with oscillating flat faced follower by low dwell angle, us-ing computer software. For  the deceleration period q2 < q < b  again we have a second order algebraic curve         s=c0+c1q+c2 q2 for the motion. 6 Draw the best profile for the cam so that the cam touches the rollers tangentially, as in the last example. Example 6.2. Additional quotes will be submitted on request. Camshaft Recommendation. Design of the cam transferred to a template or master. This means that the relative motion between them is a combination of a relative turning motion and a relative translating motion. Design of a plate cam with an In-Line knife edge follower . The acceleration of cubic#2 curve is a continuous line with a negative slope. The curve can further be modified by eliminating the sharp corners of the trapezoids. This curve will not be suitable for high or moderate speeds. The dip towards zero at the cam nose for Design E can be The optimization of the cam profile plays an important role to reduce noise and vibration in an internal combustion engine. Therefore they are not preferred.              2. It consists of a two-digit prefix designating the engine type, followed by a dash (-) and three consecutive zeros. Using the boundary conditions at the knots the coefficients are solved. However, note that the maximum velocity and acceleration within the rise period has increased. cam profile for the different constructions that follow . In a similar fashion the derivative ds/dq and  for the motion curves can be evaluated at every cam angle and the required formula can be entered into cells in Columns D and E respectively (w=1   s-1, constant).  These curves are shown below. Solving the two equations we obtain:  q1 =  p/6  (=300 ) and c2=360/p2 . Although the acceleration is finite, it will be of a high magnitude. All these methods have found use in cam design. 4. For each part a polynomial of order n is written. Pitch curve is created when we assume that the cam is fine and the tracepoint of the follower rotates around the cam. Howards2016_17_mid.pdf. It will yield a cam mechanism with the lowest vibration, stress, noise and shock characteristics. Next are The algorithm is written for ’CW’ rotation, but if the When q = q2 = p/2 s=50 mm, ; and when q = b,  s=H=60 mm and  . Note that for dwell-rise-return cams the main requirement is that there must be continuity of motion and its derivatives (velocity and acceleration). These cam profiles are typically defined in a table as a set of x-y points. 2. Jerk will be infinite at these points. In time, different ways of obtaining cam motion curves were devised. 7. Double Harmonic motion curve: This is the smallest circle of the cam profile formed from the centre rotation of the cam. when q = 0  and when q = b: ) since there are 8 boundary conditions a seventh order polynomial will be required and we obtain 4-5-6-7 polynomial as: 3-4-5 and 4-5-6-7 polynomials are compared in the above figure. It is best suited for D-R-R type of motion. The zeros indicate a custom ground cam. Camshaft diameter, 30 mm. As specified, the mapp technology multi-axis functions should be operated like the MpAxisBasic component. 180-240°, dwell period. This procedure does not give us flexibility on the motion itself. In order to compare the motion curves that were discussed we let:                   Â, w=1 rad/s Try our new cam form so we can help get you the cam that perfectly fits your needs. Simple harmonic motion curve is widely used since it is simple to design. As the cam continues to rotate the arm begins to rise as seen in diagram 4. Cam still needs to be improved for better performance of mechanical systems. 8. This must also be taken into account. This procedure is known as “normalization”. This study analyzes a method for the design and experimentation of different cam profiles. Now, let us transform these equations to the correct cam angles to obtain the equation s for 3600 cam shaft rotation: Using Excel the cam motion curve is drawn as shown in Figure 8.35. H��Wێ�6��7@��U���t�(�R�q_Y��X�V����wx�d]֋A�g��9�oh�vI#��`��4G�y���;*��|��;E�)��=|�L���o�1�_?�O0ّX In cases where the motion curve is composed of rise-return only, if the rise and return takes place for 1800 crank rotation each, simple harmonic motion curve results with a circular cam eccentrically pivoted (eccentricity = H/2, half the rise), as shown.       Â, The equations relating the follower displacement, velocity and acceleration to the cam rotation angle are: The cam profile will be discontinuous. The motion curve and velocity and acceleration curves are as shown. Depending on the application, manufacturing capabilities, etc. k���6�v�͖���xB�%s�L`g��ǯ�wU�Kg&�-�4"گ1z�B�&d<4�`��6��@X&���p�J���R�U^7�ꊺ�ո"��#�w�������z�����G��-R(�˗�ʪ�����_���+��Y5襩�✡�jѷ,���Bh����.�R����;{F]��̘۲�Q�9��)��9��&�RGۢ�T]ڬ}� X��-�с�8r�#��y}>�׬A]�������z���Hyo���7�$$���,Q��,rt�|mc< �n�=�3�O�����P�c8|� %�3�$�٥�����X�Ġ.���v ��I��T�Ba\NR�Ĵ[|N{^��-�� ��,��q7)���ѡ�V6e*����Շ���,��4�.�p��E�:��= �� Computer Program to Measure Cam Profiles (camshaft profiles) by Hand, or Analyze (graph and report) Several Various Computerized Cam File Formats like Cam Dr tm, Cam Pro Plus tm, .csv, .p, .svl, etc.. to view PDF file of user manual supplement of Version 4.3s new features with Adobe Acrobat. Base Circle: It is the smallest circle of a cam profile drawn from the center of rotation of the cam. This can be seen if we examine the diagram below. If we assume the rise for each constant acceleration periods is equal than there will be 10 mm rise for each interval. The curve is composed as the difference of two harmonics. CAM DESIGN HANDBOOK.pdf. Equation describing a linear motion with respect to time is: 3. Cubic or Constant Pulse  (#1):                                 The curve is the projection of a circle about the cam rotation axis as shown in the figure.            2c2q1w = 200mm/s •The tool begins its motion sequence from a target point PTARG located at x=0, y=-50mm and z=10mm. The maximum velocity and acceleration values are: Compared to parabolic motion curve the maximum acceleration is 57% larger. These transformations are shown below. In order to have a return starting at s=H at an angle q=g, any rise motion curve must first be subtracted from H and instead of q,  (q-g) must be substituted (s= f(q)=H-s(q-g) will be the return curve starting at q=g and s=H). Boost Logo. Due to the difference in acceleration, dynamic characteristics will all be different.            0= c1                                                                      (q=0, ) Since Cv=1.5, Ca=6, the maximum velocity and acceleration values will be: The Terminology of a Cam: Cam Profile: It is the surface area of a cam where follower touches. The mechanism of Cam and Follower is essential in the engineering field and has many different functions to the different machines. Cam Profile Drawing Example.pdf from ECON 2000 at Humber College. To avoid infinite acceleration at the ends of the rise motion, circles are drawn as shown. Or:           Let H= Total follower rise (Stroke) We have shown the motion curves for the rise and these curves start at q = 0 end at q = b with a rise s=H. CAM DESIGN HANDBOOK.pdf. Radius of curvature 9. Later we shall see how a full motion curve can be constructed. Return 20 mm in 600 cam rotation  (parabolic motion), When the follower reaches the top, the cylinder cam rotates in the opposite direction and follower moves back down. The boundary conditions is when q=0, s=0 and  (since the motion starts from a dwell period, we want continuity on velocity); and when q=q1, s=10 mm and  Using the conditions for q=0 results c0=c1=0. shows a radial cam with reciprocating roller follower. The radii of curvature of the three cam profiles are shown in Fig.5.            0= c1 + 2c2 b + 3c3 b2  +4c4 b3 +5c5 b4            (q=b,  ) Download Full PDF Package. Although it had the lowest acceleration characteristics, the third derivative was infinite at the start, midpoint and at the end of the rise period since there was a step change on the acceleration curves. 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