CNC Knowledge: Development and application of the cylindrical linear engine

The Rise of Cylindrical Linear Motors: A Revolutionary New Era in Machine Tools and Manufacturing

In recent years, the development of machine tools and manufacturing has been driven by the rapid advancement of technologies such as robotics, artificial intelligence, and nanotechnology. One area that has gained significant attention is the linear motor, a type of electric motor that generates linear motion without the need for gearboxes or belts. In this blog post, we will explore the current state of linear motors, particularly cylindrical linear motors, and their potential applications in machine tools and manufacturing.

History of Linear Motors

The first cylindrical linear motor was designed in 1917, and it was actually a reluctance motor with a primary coil switch. At that time, people tried to use it as a missile launcher, but its development exceeded the model phase. Until the mid-1950s, the rapid development of control, materials, and other technologies greatly favored the development of linear motors. In 1978, A. Mendrela and J. Turrowski designed a linear induction motor that can produce a spiral movement and was used in boring towers and machines; some people also used cylindrical linear motors in mechanical hands in machining centers.

Applications of Cylindrical Linear Motors

In recent years, the application of cylindrical linear motors in machine tools has increased and developed rapidly. Especially when the running length is less than 0.5m, the use of a cylindrical linear motor can better utilize the material, which makes the corresponding and more compact transmission structure, thus receiving high attention.

One example is the development of a stamping machine driven by a linear motor. It is mainly divided into three parts: the part of the fuselage, the part of the linear motor, and the part of the control system. The linear motor used is mainly the cylindrical linear induction motor. Its principle of basic work is to connect the power supply, start the power switch, provide the main power supply to the linear motor, generate a magnetic force, causing the secondary to linearly move, and then recover the secondary to the initial position and wait for the next stamping.

Linear Motors in Parallel Machine Tools

Another area where cylindrical linear motors are making a significant impact is in parallel machine tools. Parallel machine tools are the result of the combination of robotics technology and structural technology of machine tools. They form a mesh contrast with traditional CNC machine tools. The parallel machine adopts a parallel static or non-static stem structure, which has high rigidity, which considerably improves the dynamic response. This has drawn the attention of the global industry for manufacturing machine tools, and countries such as the United States, Japan, Europe, and Russia are extremely optimistic about the prospects for the application of engineering and the market potential of this new CNC equipment.

Measurement Machine for Parallel Coordinates

We have recently designed a measurement machine for parallel coordinates driven by a linear cylindrical engine, where the linear cylindrical engine and the drive rod are designed as a whole, and the cylindrical primary of the linear engine passes through a universal coupling and a stationary base. The principle of basic work is to transmit power to the primary winding of the linear cylindrical engine, generating a magnetic displacement wave field along the axis of the engine, and causing the secondary to telescopically contract and expand, leading to the calculation of spatial coordinates at the measurement point.

Advantages of Cylindrical Linear Motors

Compared to traditional rotary motors, cylindrical linear motors have several advantages. For example:

1. Simple structure: Cylindrical linear motors do not need to go through intermediate conversion mechanisms to directly generate linear motion, which simplifies the structure, reduces the moment of movement inertia, improves dynamic response performance, and positioning accuracy.
2. High-speed linear movement: There is no centrifugal force constraint, and ordinary materials can also reach higher speeds. Additionally, if the difference is recorded between primary and secondary levels with air cushions or magnetic cushions, there will be no mechanical contact during movement, so the mobile part will be free from friction and noise.
3. High utilization rate of primary winding: In cylindrical linear induction motors, the primary winding is of the cake and has no final winding, so the utilization rate of the winding is high.
4. No lateral edge effect: The lateral effect refers to the weakening of the magnetic field to the border caused by lateral rupture, and the cylindrical linear motor has no lateral interruption, so the magnetic field is distributed uniformly along the circumferential direction.
5. Easy to overcome the problem of unilateral magnetic tension: Radial tension forces are unnatural and there is essentially no problem with unilateral magnetic tension.
6. Easy to adjust and control: By adjusting voltage or frequency, or replacing the secondary material, different speeds and electromagnetic pushes can be obtained, which are suitable for alternative occasions at low speed.

Disadvantages of Cylindrical Linear Motors

However, cylindrical linear motors also have some disadvantages, including:

1. Low efficiency and power factor: The efficiency and power factor of the cylindrical linear motor is lower than that of the rotary motor of the same capacity, especially at low speed.
2. Sensitive starting thrust: The starting thrust of the cylindrical linear motor is sensitive to voltage fluctuations, which can cause the supply voltage to be relatively stable.
3. Limited operating speed range: The operating speed range of the cylindrical linear motor is limited by the distance from the engine post, and the engine operating speed depends to a large extent on the distance from the engine post.
4. Complex power supply: For primary linear motors, the power supply is more complicated when the speed is higher or the stroke is longer.
5. Difficult to dispel heat: The thermal dissipation conditions of cylindrical linear motors are worse than those of flat linear motors, which limits the electrical parameters authorized by the engine and thus limits the thrust of the engine.

In conclusion, cylindrical linear motors have the potential to revolutionize the field of machine tools and manufacturing, offering many advantages such as simple structure, high-speed linear movement, high utilization rate of primary winding, and easy adjustment and control. While there are some disadvantages, such as low efficiency and power factor, sensitive starting thrust, and limited operating speed range, the benefits of cylindrical linear motors make them an attractive option for many applications. As the technology continues to evolve, we can expect to see even more innovative and exciting applications of cylindrical linear motors in the future.