DE102004035675A1 - Rotor shaft for an electric motor has magnetized segments positioned alongside each other in a first axial area glued onto a rotor shaft - Google Patents

Abstract

Segments (2) as magnets have an inner radius (R1) turned towards a rotor (1) shaft. This inner radius is smaller than the radius (R2) of the rotor shaft in a first axial area, so that there is a presettable gluing/jointing gap. The segments are positioned alongside each other on the periphery and/or have alternating magnetizing directions. An independent claim is also included for a synchronous motor or brushless direct current motor.

Description

The The invention relates to a rotor shaft and a synchronous motor or brushless DC motor.

synchronous motors or brushless DC motors include a stator and a rotor, wherein the rotor carries permanent magnets.

Usually become the still unmagnetisierten magnets in manufacturing means Adhesive and a bandage fixed to the rotor. Then the rotor becomes placed in an oven until the implementation of the curing process of the adhesive is completed. Then the rotor, in particular with its magnets, in a magnetizing device exposed to such high magnetic field that the magnets reach the desired permanent magnetization. The disadvantage here is that the attachment of the bandage a manual and thus costly process. In addition, the not yet liable Magnets slip. Special magnet shapes, such as loaf magnets or the like, are not or only with difficulty by means of the bandage fixable.

Of the Invention is therefore based on the object, an electric motor or to further develop the rotor shaft, the quality of manufacture and the life should be improved.

According to the invention Task with the rotor shaft according to the claim 1 and in the synchronous motor or brushless DC motor solved according to the features specified in claim 8.

basics Features of the invention in the rotor shaft are that the rotor shaft Magnetized bonded to the rotor shaft in a first axial region Segments includes, wherein the segments facing one of the rotor shaft Inner radius R1 have, which is so smaller than the radius R2 of the rotor shaft in this axial range, that is a predeterminable Adhesive gap is provided.

From The advantage here is that the adhesive gap is defined executable. This means that when specifying the radii even when occurring Manufacturing deviations sufficient greater and expedient adhesive gap can be produced. The radii are like that selectable, that within the manufacturing tolerance a sufficient adhesive gap produced is and thus a sufficient bond for securing the segments can be reached on the rotor shaft, resulting in great manufacturing process reliability leads.

at an advantageous embodiment, the segments on the circumference are positioned side by side and / or alternating magnetization directions on. The advantage here is that the invention in a simple round wave contour of a brushless DC or a permanent-magnet synchronous motor is applicable, including with servomotors comprehensive drives.

at an advantageous embodiment, the adjacent to the circumference Segments above a critical temperature, in particular lowest permissible storage temperature or operating temperature, spaced, so non-contact, arranged. The advantage here is that the segments no pressure on each other exercise can and thus can not break off.

at According to an advantageous embodiment, the outer radius of the segments is smaller as the inner radius of the segment. The advantage here is that the Nutrasten is reducible in this way.

at an advantageous embodiment, the rotor shaft in a further axial region thickening. It is advantageous that imbalance is compensable.

at According to an advantageous embodiment, the rotor shaft comprises a keyway. The advantage here is that on the output side other components form-fitting connectable are, in particular for torque transmission.

at an advantageous embodiment, the adhesive gap in the radial Direction a maximum height on, the values between 0.05 mm and 0.3 mm assumes. Advantageous is there that a particularly good adhesive strength with a long service life is reachable.

basics Features of the invention in the synchronous motor are that at least one of said rotor shafts is provided in it. Advantageous is that the synchronous motor has only slight clogging and its rotor shaft from a cost-effective rotating part safely manufacturable is.

Further Advantages emerge from the subclaims.

1

rotor

2

segment

21

balancing

22

keyway

R1

inner radius a segment

R2

radius of the rotor

R3

outer radius a segment

The invention will now be explained in more detail with reference to figures:
In the 1 is a schematic section through the rotor 1 an electric motor according to the invention shown. The magnets are as segments 2 alternately magnetized juxtaposed and glued to the rotor.

The rotor 1 has a radius R2 that is greater than the inner radius R1 of a segment. Thus, there is enough space as an adhesive gap for receiving adhesive.

By the determination of the radii R1 and R2 is also the gluing gap exactly definable. By limitation the inhomogeneities the bond is improved overall.

Of the outer radius of the segment R3. Advantageously, this is smaller than R2 and also smaller as R1. Thus, the segment has a loaf shape, with which the Polrasten the electric motor, in particular a servo motor, reducible is.

The distance X is used to compensate thermally induced expansions. At the lowest permissible storage temperature or operating temperature it assumes negligible values. In the context of manufacturing tolerances then also mutual contact of the segments occur 2 on. As the temperature increases, the distance X becomes larger because of the magnetizable material of the segments 2 a different thermal expansion coefficient than the material of the rotor shaft 1 Has. As material of the rotor shaft 1 Advantageously, steel is used.

The segments 2 are either straight running in the axial direction, that is designed according to a spur gear with helix angle zero. This means that the inner surface is an inner cylinder section with inner radius R1 and the outer surface is an outer cylinder with radius R3.

2 shows such a rotor shaft, with a thickening as unbalance compensation 21 and a feather keyway 22 is shown for positive connection.

at further embodiments a finite non-zero skew angle is implemented. Thereby let yourself Further reduce groove and / or pile locks.

The adhesive gap points in at its maximum height 1 Advantageously, a height of 0.1 mm. But there are also adhesive gaps advantageous, the values between 0.05 mm and 0.3 mm. In this area it was found that surprisingly good adhesion effects can be achieved.

Claims (8)

Rotor shaft comprising in a first axial region of the rotor shaft glued on magnetized segments, characterized in that the segments have an inner radius R1 facing the rotor shaft, which is smaller than the radius R2 of the rotor shaft in this axial region, that a predeterminable adhesive gap is provided , Rotor shaft according to at least one of the preceding Claims, characterized in that the segments on the periphery next to each other are positioned and / or alternating magnetization directions exhibit. Rotor shaft according to at least one of the preceding Claims, characterized in that the circumferentially adjacent segments above a critical temperature, in particular lowest permissible storage temperature or operating temperature, spaced, so non-contact, arranged are. Rotor shaft according to at least one of the preceding Claims, characterized in that the outer radius of the segments smaller is the inner radius of the segment, in particular for reduction of the grouts. Rotor shaft according to at least one of the preceding Claims, characterized in that the rotor shaft in a further axial Area has a thickening for balancing. Rotor shaft according to at least one of the preceding Claims, characterized in that the rotor shaft comprises a keyway. Rotor shaft according to at least one of the preceding Claims, characterized in that the adhesive gap in the radial direction a maximum height having values between 0.05 mm and 0.3 mm. Synchronous motor or brushless DC motor, characterized in that the rotor shaft after at least one of the preceding claims accomplished is.