CS202426B1 - Rotor of the high-revolution electric machine - Google Patents

Description

The invention relates to a rotor of a high-speed permanent magnet electric machine, preferably of rare earth.

High-speed valve motors are designed as multi-pole machines with external rotor, rare earth permanent magnets with high demagnetization resistance and high energy product are located and adhered to the inside of a steel ring that holds the magnets against centrifugal force while closing the return path magnetic flux. The ring is embedded in a cup-type part which is connected to the motor shaft. The disadvantage of these machines is the large surface of the rotor and thus the friction losses on the air, so that the maximum speed achieved is around 100,000 rpm. Solutions with welded magnets near the air gap of the machine are also known. However, these machines achieve even lower speeds.

These disadvantages are overcome by the rotor of the high-speed machine according to the invention, which consists of a hollow smooth cylinder welded from 2p magnetic segments forming machine poles and from 2p non-magnetic segments filling the space between the poles. axial planes, it is filled with a permanent magnet, the edges of the cylinder are provided with shoulder, on which are mounted and welded the front bores of non-magnetic material, on which the pins for bearing the rotor in bearings are formed. This design, together with the use of high-performance rare earth permanent magnets whose effect is enhanced by the magnetic flux concentration in the axial direction of the machine, allows the rotor to be small in diameter and can be operated at speeds in excess of 150,000 rpm. The limiting parameters here are the strength of the steel materials used and the size of the welds. Their precise design and mechanical strength ensures electron beam welding. Placing permanent magnets on the rotor axis means minimal mechanical stress during machine operation.

An exemplary embodiment of the rotor according to the invention is shown in the accompanying drawing, in which Fig. 1 shows a partial axial sectional view of the rotor, and Fig. 2 shows the rotor in section A-A according to Fig. 1.

The illustrated rotor of a high-speed two-pole electric machine consists of a hollow cylinder welded from two magnetic segments 1 and two non-magnetic segments 2. The square cavity of the cylinder is filled with a permanent magnet 3 magnetized so that the magnetic segments 1 form the poles of the machine. The cylinder is provided at the edges with shoulder 4 on which the front choke 5 of non-magnetic material is mounted and welded. To them are welded pins 6 of magnetic material for bearing the rotor in bearings. With respect to

202 426

202 426 precision of construction and for mechanical reasons all welds are made by electron beam under vacuum. The front punches 5 not only assist the mechanical strength and stiffness of the rotor, but also cause the magnetic flux concentration of the permanent magnets 3 in the axial direction of the machine.

A multi-pole rotor can be created in the same way as a two-pole. The permanent magnet 3 is a single piece, but can be divided in both the radial and axial directions of the machine. In order to achieve the highest possible speed, the cross-section of the magnet 3 in a plane perpendicular to the axis of rotation is symmetrical to two mutually perpendicular axes. The pins 6 may also be made of a non-magnetic material, then form a single unit together with the front socks S.

In order to manufacture the rotor, the hollow cylinder is first welded from the alternately arranged magnetic and non-magnetic segments 1, 2, then the cavity, the outer surface is machined, a shoulder 4 is formed, a front chuck 5 is fitted and welded into the cylinder cavity. The permanent magnet 3 is magnetized either before insertion into the rotor or after the entire rotor has been manufactured. In the latter case, there is no need to clean the rotor of any trapped material after all mechanical operations have been completed. If the pins 6 are made of a non-magnetic material, the use of which is preferable in terms of machining, they are welded on the front nipple 5 before being mounted on the shoulder 4 of the cylinder.

Claims (8)

OBJECT OF THE INVENTION A rare-earth high-speed electric machine, in particular a valve motor, with permanent magnets, characterized in that it consists of a hollow smooth cylinder welded from 2p (2p = bipolar) magnetic segments (1j forming the machine poles) and 2p non-magnetic segments (2). ) filling the spaces between the poles, where 2p is the number of poles of the machine, the cylinder cavity, symmetrical to two perpendicular axial planes, is filled with a permanent magnet (3), the edges of the cylinder are provided with shoulder (4j). 5) of a non-magnetic material on which the pins (6j) are formed to receive the rotor in the bearings. Rotor according to Claim 1, characterized in that the front bores (5) form a single unit with the pins (6). Rotor according to Claim 1, characterized in that pins (6) made of magnetic material are welded to the front shroud (51). 4. A method according to any one of claims 1 to 3, wherein the hollow cylinder is welded from the alternately arranged magnetic and non-magnetic segments, the cylinder cavity is machined, the outer surface is formed and a shoulder is formed, a permanent magnet is inserted into the cavities and the second shrink disk is welded on and welded. 5. Method according to claim 4, characterized in that the pins are made of non-magnetic material and welded to the front shroud before they are mounted on the cylinder stock. 6. A method according to any one of claims 4 and 5, characterized in that all welds are performed by electron beam under vacuum. 7. A method according to claim 4, wherein the permanent magnets are magnetized prior to insertion into the cavity of the rotor cylinder. 8. A method according to claim 4, wherein the permanent magnets are magnetized upon completion of the rotor.