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The composition and type of cam mechanism

Update:23-06-2022
Summary:

First, the composition of the cam mechanism 1. Cam: a m […]

First, the composition of the cam mechanism
1. Cam: a member with a curved profile or groove, when it moves, it contacts the high pair of the follower through the curved profile on it, so that the follower obtains the desired movement.
2. The composition of the cam mechanism: a high auxiliary mechanism composed of three basic components: cam, follower and frame.
Second, the type of cam mechanism
1. According to the shape of 304 stainless steel beer keg the cam:
Disc Cam: The cam is disc-shaped and has a variable radial diameter. It is the most basic form of cam and the most widely used.
Moving (wedge) cam: The cam is plate-like and moves linearly relative to the frame. The disc cam shaft is located at infinity.
Space cam mechanism:
Cylindrical cam: The contour curve of the cam is made on the cylinder.
2. According to the shape of the follower:
(1) Tip follower The tip of the follower can be in contact with a cam of any shape, so that the follower can achieve any law of motion. The structure is simple, but the tip is easy to wear, and it is suitable for occasions with low speed and low force transmission.
(2) Curved follower: The end of the follower is made of curved surface, which is not easy to wear and is widely used.
(3) Roller follower: Sliding friction becomes rolling friction, which transmits greater power.
(4) Flat-bottomed follower
Advantages: It is easy to form an oil film between the flat bottom and the cam, and the lubrication state is stable. When friction is not counted,
The force of the cam to 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 at high speed.
Disadvantage: The cam profile must be all convex.
3. According to the movement form of the follower: swing follower cam and move follower cam.
4. According to the method of maintaining high contact between the cam and the follower:
(1) Force-closed cam mechanism: use gravity, spring force or other external force to keep the follower in contact with the cam profile all the time. The closing method is simple, and there is no restriction on the movement law of the follower.
5. Other
Reverse cam mechanism: the swing rod is the driving part, and the cam is the driven part.
Application example: automatic groove milling machine uses reverse cam to realize hopper turnover

The cam mechanism is a common motion mechanism, which is a high sub-mechanism composed of a cam, a follower and a frame. When the displacement, speed and acceleration of the follower must be changed strictly according to the predetermined law, especially when the original mover moves continuously and the follower must move intermittently, the cam mechanism is the most convenient. The movement law of the cam follower depends on the contour of the cam or the shape of the groove. The cam can convert the continuous rotational movement into a reciprocating linear movement, which can realize complex movement laws. Cam mechanisms are widely used in various automatic machines, instruments and manipulation control devices. The reason why the cam mechanism is so widely used is mainly because the cam mechanism can realize various 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 push rod can obtain various expected motion laws.
When the cam mechanism is used for the transmission mechanism, it can produce complex motion laws, including non-constant speed motion with a large speed change range, and temporary stop or various stepping motions; the cam mechanism is also suitable for use as a guiding mechanism to make the work Components produce complex trajectory or planar motion; when a cam mechanism is used as a control mechanism, the automatic duty cycle of the actuator can be controlled. Therefore, the design and manufacturing method of the cam mechanism is of great significance to the modern manufacturing industry.

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