The principle and use of permanent magnet lifter
Permanent magnet hoist
A: Introduction to permanent magnet lifting device:
In China's mechanical processing, mold manufacturing, metallurgical and other industries, some heavy steel or iron plate, there are precision requirements or surface roughness requirements of steel processing products or semi-finished products such as lifting, previously used mostly rope tied up and then lifted, or useful The electromagnets are lifted, but the electromagnets are bulky, costly, troublesome, and difficult to maintain. In addition, the electromagnets consume a large amount of electric power during work. In the event of a power outage, the electromagnets are prone to accidents. With the rise of high-performance neodymium-iron-boron rare-earth, it is an essential transportation tool for steel factories, mold factories, forging plants, steel mills, shipyards, etc., which can greatly increase the quality of blocks, columns, plates, and irregularities. Magnetically conductive steel material handling efficiency. The permanent magnet lifting device is made of high-performance rare earth material NdFeB (N>40) as the core, and the magnetic system of the NdFeB inside the sucker is changed by turning the handle of the sucker by hand, so as to achieve the holding of the workpiece to be carried. Or release.
II: The principle of permanent magnet lifter:
The permanent magnet lifting device is designed using the principle of magnetic flux continuity and the superposition principle of a magnetic field. The magnetic circuit of the permanent magnet lifting device is designed into a plurality of magnetic systems. By the relative movement of the magnetic system, the magnetic field intensity on the working magnetic pole surface is realized. Add or cancel, so as to achieve the purpose of suction and unloading.
Figure 1 Working principle of a permanent magnet lifter
Its working principle is shown in Fig. 1. When the pole of the permanent magnet lifting device is in the state of Fig. (a), the magnetic flux comes out from the N pole of the magnet, passes through the yoke, passes through the ferromagnetic workpiece, and then returns to the yoke and enters the S pole of the magnet. . In this way, the work piece can be firmly sucked on the work pole surface of the permanent magnet lifter. When the magnetic pole is in the state of figure (b), the magnetic flux is less than the working pole face of the permanent magnet lifting device, and a closed loop of the magnetic circuit is formed inside the permanent magnet lifting device, and almost no magnetic force lines emerge from the working pole face of the permanent magnet lifting device. , so the workpiece does not generate suction, you can successfully achieve the uninstall.
Design of permanent magnet lifter:
1. Magnet lifting system and yoke
When designing a permanent magnet hoist, the magnetic circuit should be carefully designed. A good magnetic circuit structure can concentrate more magnetic flux on the working surface to meet the lifting weight requirements, and neodymium iron boron material can be used as little as possible. At the same time, when designing the magnetic circuit, it is also necessary to carefully consider that the operator can easily achieve the work uninstallation. Solve the technical difficulties of the permanent magnet lifter with large suction and difficult to pull the handle.
The magnetic circuit of the permanent magnet lifting device is designed with two magnetic systems. The magnetic system is divided into two parts: active and fixed. Change the state of the active magnetic system so that the working polar planes are in a magnetic field superposition or a reverse magnetic field is generated, and the magnetic fields are canceled. At the same time, in the permanent magnet circuit, in order to reduce the magnetic resistance and increase the magnetic flux density at the critical part of the working polar surface, some soft magnetic materials are used as the yoke.
2. Working point selection of permanent magnet lifter
Due to the wide variety of workpieces that are hoisted, the distance between the work pole surface of the permanent magnet lifting device and the surface of the workpiece changes, and its magnetic circuit is a dynamic magnetic circuit. As shown in FIG. 2 , the recovery curve of the NdFeB permanent magnet of FIG. 2 and the working point diagram of the working point of the permanent magnet are changed on the recovery curve (AD). When the permanent magnet lifting device is in the open state, the working point of the permanent magnet is represented by point A on the demagnetization curve; when the working pole surface of the permanent magnet lifting device is completely and seamlessly engaged with the workpiece, the working point is D point. The flux of the permanent magnets all passes through the workpiece. During the process of the permanent magnet lifting device approaching the workpiece surface, the working state of the permanent magnet moves from the A point to the D point; in return, the permanent magnet lifting device moves away from the workpiece, and the working state of the permanent magnet moves from the D point to the A point. Since these two curves are very close, they can be approximately replaced by a straight line AD. OA is a permanent magnet load line. The useful recovery energy (Erec) is the product of the useful magnetic flux density B and the demagnetizing field strength H in the permanent magnet operating point (Erec=B*H).
That is, the area of the area line EFGC in FIG. 2 . The operating point of the E-point permanent magnet should be designed so that the E point is close to the midpoint of the return curve AD so that the useful recovery energy of A is the starting point.
Three: The characteristics of permanent magnet lifting device:
1) Permanent-magnet hoist The high-performance permanent magnet material Nd-Fe-B is used as the core of the product to make the product smaller, lifting and lifting force stronger, and the magnetic force will last forever.
2) The permanent magnet hoist has a safety factor of 3.5 times that of the high rated lifting capacity.
3) Permanent magnet lifting device The bottom "V" groove design can lift the corresponding round steel and steel plate.
4) The permanent magnet lifter can be used without electricity, eliminating the need for power supply.
5) Permanent magnet hoist The optimized magnetic circuit design makes the remanence almost zero.
6) Permanent magnet lifter The professionally designed appearance makes the product more beautiful.
How to use the permanent magnet lifting device:
1. Place the workpiece on the chuck table, then insert the wrench into the shaft hole and turn it clockwise 180 to "ON" to suck the workpiece for processing.
2. After the workpiece has been machined, insert the wrench into the shaft hole and turn it 180° to “OFF” counterclockwise to remove the workpiece.
Permanent magnet lifter maintenance and service:
1. The surface of the suction cup should be wiped before use to avoid scratches affecting the accuracy
2. The use of ambient temperature -40C--50C, is strictly prohibited tapping, to prevent the magnetic force is reduced.
3 After use, antirust oil is applied on the work surface to prevent corrosion.