Table of Contents
How do you design a cam?
Design of the Cam Profile Draw the 100 mm diameter base circle. Now draw the outermost of the concentric circle. Since, there is no offset of the follower; hence the cam will be aligned with AB. Now divide the base circle and the outermost circle by 300 sectors.
What is the law of cam design?
Fundamental Law of Cam Design Any cam designed for operation at other than very low speeds must be designed with the following constraints: • The cam function must be continuous through the first and second derivatives of displacement across the entire interval (360°).
What are the three types of cam?
Cams Circular. Circular cams use an off-centre pivot to cause the follower to move up and down. Pear. Pear cams are called this as they have the shape of a pear. Snail or drop. Snail or drop cams have the appearance of a snail shell. Heart-shaped or constant velocity.
What is a typical cam shape?
Cams come in a variety of shapes and sizes – the most common types (from left to right): snail shaped, pear shaped and a circular with an off-centre hole. As the cams rotate, the followers reciprocate motion according to the profile of each cam.
What are the different types of cam profile?
Types of Cams Wedge or flat cam. Disk or Plate cam. Spiral cam. Cylindrical cam. Heart-shaped cam. Translating cam. Snail drop cam. Conjugate cam.
How do you avoid jerk in a cam and follower motion?
The way to avoid jerk is to reduce the rate of acceleration or deceleration. In motion control systems, this is done by using an S-curve motion profile, instead of the “jerky” trapezoidal profile. In a trapezoidal move profile, acceleration occurs instantly (at least in theory) and jerk is infinite.
What is the maximum value of pressure angle of cam?
15° 20°.
How many types of cam followers are there?
There are various types of cams available, that are listed below: Disk or Plate cam. Cylindrical cam. Translating cam.
What is cam profile?
CAM Nomenclature • Cam profile is the actual working surface contour of the cam. It is the surface in conta ct with the knife-edge, roller surface, or flat -faced follower. CAM Nomenclature Base circle is the smallest circle drawn to the cam profile from the radial cam center.
What is cam purpose?
A camshaft acts as a timing device that controls the opening and closing of the intake and exhaust valves, as well as setting the valve overlap that occurs at the top dead centre on the exhaust stroke. The shaft is constructed with several journals that ride on bearings within the engine.
What are some examples of cams?
Examples of CAM include: Traditional alternative medicine. This field includes the more mainstream and accepted forms of therapy, such as acupuncture, homeopathy, and Oriental practices. Body. Touch has been used in medicine since the early days of medical care. Diet and herbs. External energy. Mind. Senses.
What does a egg shaped cam do?
Cams are a simple mechanism that can be used to create quite complex movements. In a simple cam such as the egg shaped cam shown here, the cam follower is stationary for most of the turn before rising and falling smoothly but quickly in the last portion of the turn.
What do cam followers do?
Crowned cam followers are used to keep the load evenly distributed if it deflects or if there is any misalignment between the follower and the followed surface. They are also used in turntable type applications to reduce skidding.
What is the first step in drawing cam profile?
1 Draw the cam graph as shown. 2 Draw a 20 mm radius circle, and divide it into 30° divisions as shown. 3 Where the 30° lines touch the circumference of the 20 mm circle, draw tangents at these points. 4 Draw a circle of radius Q, as shown, from the centre of the camshaft to the centre of the roller follower.
What is a displacement diagram Why is it necessary to draw it before drawing a cam profile?
A Displacement Diagram is essentially a graph which plots the movement of a cam follower against time. Since the cam’s movement is usually constant then equal time intervals can be represented by equal distances along the horizontal axis and the resulting follower movement (or ‘displacement’) along the vertical axis.
What are the necessary elements of a cam mechanism?
The cam convert rotary motion of one element into reciprocating (linear motion) or into oscillatory motion. Cam is a driver member and follower is a driven member. A cam mechanism consists of three elements: a) the cam, b) the follower (or follower system), c) and the frame.
What is spherical cam?
Spherical cam-follower mechanisms are attractive alternatives to bevel gears, as they provide low backlash and low friction losses. The pressure angle, an important factor that governs the effective force transmission of cam mechanisms, is duly kept within acceptable limits.
What is base circle in cam?
Base circle It is the smallest circle that can be drawn tangential to the cam profile (contour) from the centre of rotation of a radial cam. The base circle decides the overall size of a cam and is, therefore, a fundamental feature of the cam.
How do you find the velocity of a cam?
Angular velocity of the cam is given as w=50*p/30 = 5.238 s-1, therefore p/3 cam rotation will take place within Dt= 0.2 s. If the speed of the follower is kept at 200 mm/s during this phase of the motion, then the amount of rise with constant velocity is H’=200*0.2= 40mm.
How do you calculate jerk?
Jerk is the rate of change of acceleration with time. This makes jerk the first derivative of acceleration, the second derivative of velocity, and the third derivative of position. The SI unit of jerk is the meter per second cubed . An alternate unit is the g per second .constant jerk. a = a 0 + jt [1] = a = f(s) [4].
How do you find the velocity of a cam and follower?
Conclusion. The velocity of any cam follower can be calculated using the deferential method provided you have the equation relating the angular displacement of the cam and the linear displacement of the follower. Also you need to have the rotational speed of the cam.
