According to the geometry of the cam mechanism, it is divided into those three

A cam is a member with a curved profile or groove

Generally, it can be divided into three categories according to the appearance:

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

Moving cam: the cam moves in a straight line relative to the frame;

Cylindrical cam: A cam is a cylinder, which can be seen as a cylinder that rolls a moving cam into a cylinder.

The cam mechanism is generally a high auxiliary mechanism composed of three components: cam, follower and frame. The cam is usually rotated at a continuous constant velocity, and the follower is designed according to the requirements of use to make it obtain a certain regular movement The cam mechanism can realize complex motion requirements and is widely used in various automated and semi-automatic mechanical devices. The cam mechanism usually consists of two moving parts, the cam and the follower, both of which are fixed to the seat frame.

The cam mechanism is quite varied, so almost any movement can be generated by this mechanism. A cam can be defined as a mechanical component with a curved surface or groove that oscillates or rotates to provide a pre-set motion to another component, the follower. The path of the follower is mostly confined to a chute to obtain reciprocating motion.

In its recovery stroke, it sometimes relies on its own weight, but some mechanisms often use springs as the recovery force in order to obtain accurate movements, and some use guide grooves to make them move on a specific path. Simple cam structure [1] The role of the cam mechanism in this section The main function of the cam mechanism is to make the driven rod complete various complex movements according to the work requirements, including linear motion, swing, constant velocity motion and unequal velocity motion. Classification of this segment A cam is a member with a curved profile or groove.

Classified by cam shape.

1) Disc cam: This kind of cam is a disc part that rotates around a fixed shaft and has a variable diameter, such as. When it rotates around a fixed shaft, it propels the follower in a plane perpendicular to the cam shaft. It is the most basic type of cam, with simple structure and the most widely used.

2) Moving cam: When the rotating shaft of the disc cam is located at infinity, it evolves into the moving cam (or wedge cam) shown in Figure 3. The cam is plate-shaped, and it moves in a straight line relative to the frame.

3) Cylindrical cam: If the moving cam is rolled into a cylinder, it will evolve into a cylindrical cam. Fig. 4 is the feed mechanism of automatic machine tool. In this cam mechanism, the relative motion between the cam and the follower is space motion, so it belongs to the space cam mechanism.

Cam mechanisms are widely used in a variety of automatic machinery, instrumentation and manipulation controls. The reason why the cam mechanism has been so widely used is mainly because the cam mechanism can realize a variety of complex motion requirements, and the structure is simple and compact, and the required motion law can be accurately realized. As long as the contour curve of the cam is properly designed, the actuator can get various expected motion laws.

1. The movement law of the air valve stem stipulates the contour shape of the cam. When the cam profile with sagittal diameter change is in contact with the flat bottom of the air valve stem, the air valve stem produces reciprocating motion; When the arc profile centered on the center of the cam rotation comes into contact with the air valve stem, the air valve stem will be stationary. As a result, with the continuous rotation of the cam, the valve stem can be moved intermittently and regularly as expected.

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 all depends on the shape of the groove.

Structural composition. 1. Cam.

A cam is a rotating or sliding part of a machine (such as a wheel or a protruding part of a wheel) that transmits motion to a roller moving close to its edge or to a needle bar that moves freely on the groove surface, or from which it receives the force.

The cam follower can be designed to meet almost any input-output relationship in its range of motion - for some uses, the cam and the connecting rod can play the same role, for the work that can be used for both, the cam is easier to design than the connecting rod, and the cam can also do many things that the connecting rod can not do, on the other hand, the cam structure is easier to manufacture than the connecting rod machine.

2. a follower.

The member that is in contact with the cam contour and transmits power and realizes the predetermined motion law does reciprocating linear motion or swing, which is called a follower. The basic feature of the cam mechanism in the application is that it can make the follower obtain a more complex motion law. Because the motion law of the follower depends on the cam profile curve, in the application, as long as the cam profile curve is designed according to the motion law of the follower.

The above content reference: Encyclopedia - Cam.

Encyclopedia - Cam mechanism.

The cam mechanism is a high auxiliary mechanism composed of three basic components: cam, follower and frame. The cam is a component with a curved profile or groove, generally a moving member, which is used for constant velocity rotary motion or reciprocating linear motion. The rotary motion or reciprocating motion of the cam pushes the follower to make a mechanism for prescribed reciprocating movement or oscillation.

The cam has a curved profile or groove, and there are disc cams, cylindrical cams and moving cams, etc., wherein the groove curves of the cylindrical cam are space curves, so they belong to space cams. The follower is in point contact or line contact with the cam, and there are roller followers, flat-bottom followers and tip followers. The tip follower can maintain contact with any complex cam profile and can realize any movement, but the tip is easy to wear, and is suitable for low-speed mechanisms with low force transmission.

In order to keep the follower in contact with the cam at all times, a spring or gravity can be applied. The cam with groove can make the follower transmit a definite motion, which is a kind of confirmed cam. Generally, cams are active, but there are also driven or fixed cams.

Most cams are single-degree-of-freedom, but there are also splitting cone cams with dual degrees of freedom. The cam mechanism has a compact structure and is most suitable for occasions that require intermittent movement of followers. Compared with similar mechanisms in hydraulics and pneumatics, it moves reliably, so it is widely used in automatic machine tools, internal combustion engines, printing presses, and textile machines.

However, the cam mechanism is easy to wear and noise, and the design of the high-speed cam is more complex and the manufacturing requirements are higher.

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There are three types of spire followers, roller followers and flat-bottom followers.

Classified by follower shape.

1) Spire follower: The tip of the follower can maintain contact with any complex cam profile, so that the follower can achieve arbitrary motion law. This kind of follower has a simple structure, but it is easy to wear at the tip, so it is only suitable for occasions with low speed and low force transmission.

2) Roller follower: In order to reduce friction and wear, a roller is installed at the end of the follower, and the sliding friction between the follower and the cam is turned into rolling friction, so the friction and wear are small, and can be used to transmit larger power, so this form of follower is widely used.

3) Regular shed of flat bottom follower: the follower and the cam profile are in line contact, and the contact is easy to form an oil film, and the lubrication condition is good. In addition, when the friction is not counted, the force of the cam on the follower is always perpendicular to the flat bottom of the follower, the force is stable, the transmission efficiency is high, and it is often used in high-speed occasions.

The disadvantage is that the cam profile must be lifted, and all of them must be convex shaped.

4) Surface follower: In order to overcome the shortcomings of the tip follower, the end of the follower can be made into a curved surface, which is called a surface follower. This structural form of driven staring parts is widely used in production.

According to the shape of the cam, the cam mechanism can be divided into: disc cam, moving cam, cylindrical cam, and conical cam. According to the shape of the driven rod, the cam mechanism can be divided into the pointed driven rod cam mechanism, the roller driven rod cam mechanism and the flat bottom driven rod cam mechanism.