What Is a Cam Sprocket?

A cam refers to a mechanical turning or sliding member (such as a wheel or a protruding part of a wheel) that transmits motion to a roller that moves close to its edge or a needle bar that moves freely on the groove surface, or it moves from such a roller and Bearing force in the needle bar. The cam follower can be designed to meet almost any input-output relationship within its range of motion. For some uses, the cam and the link mechanism can play the same role (the choice of the two studies often depends on the designer- (Translator's Note) For the work that can be used by both, cams are easier to design than link mechanisms, and cams can do many things that link mechanisms cannot do. On the other hand, cam structures are The machine is easy to manufacture. ^[1]

The main function of the cam mechanism is to make the follower rod complete various complicated movements according to the work requirements, including linear movement, swing, constant speed movement and unequal speed movement.

A cam is a member with a curved profile or groove.

Generally, they can be divided into three categories according to their appearance:

Disc cam : The cam is a disc-shaped member that rotates around a fixed axis and has a varying diameter;

Moving cam : The cam moves linearly relative to the frame;

Cylindrical cam : The cam is a cylinder, which can be seen as rolling a moving cam into a cylinder.

Classification by shape of follower :

Top follower;

Roller follower;

1. The law of motion of the air valve rod defines the contour of the cam. When the cam profile with a change in sagittal diameter contacts the flat bottom of the valve stem, the valve stem reciprocates; and when the contour of the arc segment with the center of rotation of the cam as the center contacts the valve stem, the valve stem will stand still . Therefore, with the continuous rotation of the cam, the valve stem can obtain intermittent, regular motion.

2. When the cylindrical cam rotates, the side of the groove forces the swing follower to swing, thereby driving the tool holder connected to it to move. As for the movement of the tool holder, it depends entirely on the shape of the groove.

1.The advantages of cam mechanism

Just by designing the proper cam profile, the follower can get any desired movement, and the structure is simple, compact and convenient to design. Therefore, it is suitable for automatic machine tools, light industry machinery, textile machinery, printing machinery, food machinery, packaging machinery and It is widely used in mechatronic products.

2. Disadvantages of the cam mechanism

1) There is point or line contact between the cam and the follower, which is easy to wear and should only be used in places where the force is not large;

2) The cam profile requires high accuracy, which needs to be processed by CNC machine tools;

3) The stroke of the follower must not be too large, otherwise the cam will become bulky.