Rotor for external rotor motor and method for manufacturing the same

Abstract

This invention provides a rotor for an external rotor motor that can operate without generating noise, and a method for manufacturing it with minimal effort. [Solution] A filler material is filled into the gap between the outer surface of an annular laminate (1) of steel plates welded to the rotor of an external rotor motor and the inner surface of the carrier (3) into which the annular laminate (1) is inserted, through radially extending filling openings (5) such as continuous holes provided in the carrier (3). The filler material suppresses the relative movement between the annular laminate (1) and the carrier (3), and the associated noise, especially rattle.

Description

TECHNICAL FIELD

[0001] The present invention relates to a rotor for an external rotor motor, comprising an annular laminated body of steel sheets, permanent magnets mounted on the inner side of the laminated body, and a carrier into which the laminated body is inserted. A rotor having the features specified in the preamble of Claim 1 is disclosed in Patent Document 1. BACKGROUND ART

[0002] The problem with such rotors is that even a slight imbalance can cause relative movement between the carrier and the laminated body, which may in particular cause noise such as rattling sounds. To solve this problem, strict manufacturing tolerances are usually specified, and the rotor is carefully balanced, for example by removing material at specific positions. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0003] PATENT DOCUMENT 1 German Patent Application Publication No. 10 2023 119 408 A1 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0004] An object of the present invention is to provide a rotor for an external rotor motor that can operate without generating noise, and a method for manufacturing this rotor with less effort.

[0005] This problem is solved by a rotor having the features of Claim 1 and a method according to Claim 9. Advantageous improvements of the present invention are the subject matter of the dependent claims. MEANS FOR SOLVING THE PROBLEM

[0006] In the rotor according to the present invention, the gap between the outside of the laminate and the inside of the carrier is filled with a filler (e.g., adhesive). In conventional rotors, considerable effort was required to avoid such gaps and relative movements between the laminate and the carrier, but this is no longer necessary in the rotor according to the present invention. This is because the filler significantly suppresses the relative movement between the sheet and the carrier, and the associated noise, especially rattle.

[0007] The filler can be injected, for example, after the laminate has been inserted into the carrier, through radially extending openings such as a series of holes within the carrier. Preferably, the carrier is provided with multiple filler openings. The multiple filler openings can be arranged circumferentially. [Effects of the Invention]

[0008] An advantageous improvement of the present invention is that the filling opening is configured to widen outward from the carrier. For example, the opening has a conical portion that widens outward from the carrier, followed by a cylindrical portion that leads to the gap. This facilitates the injection of the filler material.

[0009] Another advantageous improvement of the present invention is that the carrier has a notch on its axial end face, the notch extending from the inside to the outside of the carrier. Such a notch makes it easier to control the injection of filler, for example, by visually monitoring the notch. When the filler from the gap enters the notch between the sheet metal laminate and the carrier, the gap can be considered sufficiently filled, and therefore the injection of filler can be stopped. The distance between the edge of the carrier and the filling opening can be minimal in the notch. Typically, during the filling process, the filler spreads uniformly in all directions in the gap between the laminate and the carrier. In other words, the filler forms a roughly disc-like shape between the sheet metal laminate and the carrier. This causes the filler to first flow out from the gap between the laminate and the carrier into the notch. To monitor the injection of filler, a small notch with a depth of no more than twice the width of the filling opening is sufficient. It is desirable that the notch be narrow so that the injection of filler can be stopped when only a small amount of filler has flowed in. For example, a notch with a width of no more than twice the width of the filling opening is sufficient. The width of the cut shall be measured in the circumferential direction of the carrier.

[0010] A further advantageous improvement of the present invention is to provide the carrier with slots extending in the axial direction of the rotor. Clamps can be placed in these slots to press the laminate against the carrier in the axial direction. When adhesive is used as the filler, the filler can support or even replace the mechanical connection between the carrier and the laminate. However, especially under high mechanical loads, it is generally possible to more securely fix the laminate to the carrier by using clamps.

[0011] A further advantageous improvement of the present invention is that the slots open toward the distal end, i.e., toward the side away from the rotor hub. Preferably, the slots widen toward the distal end. For example, the slots have funnel-shaped ends. This facilitates the insertion of the laminate into the carrier.

[0012] Details and advantages of the present invention will be described in the embodiments of the present invention with reference to the accompanying drawings. [Brief explanation of the drawing]

[0013] [Figure 1] Perspective view showing a rotor according to an embodiment of the present invention. [Figure 2] Perspective view of the rotor from a different angle. [Figure 3] A diagram showing details of the enlarged cross-section of the rotor. [Figure 4] A perspective view showing an enlarged view of the main part of Figure 2. [Figure 5] Enlarged perspective view showing details from inside the rotor carrier. [Modes for carrying out the invention]

[0014] Figures 1 and 2 show the rotor of an electric motor, more specifically, an external rotor motor. The rotor has a laminated core consisting of an annular laminate 1 of iron magnetic steel sheets, which are made of, for example, electromagnetic steel sheets or other soft magnetic steel sheets. The individual steel sheets of the laminate 1 may be annular steel sheets, or each may only form annular segments. Inside the laminate 1 is, for example, Nd2Fe 14 A permanent magnet 2, made of base material B, is attached. The permanent magnet 2 is placed, for example, in a groove in the laminate 1 and fixed with an adhesive or the like. The laminate 1 is inserted into a carrier 3 having a hub for the shaft.

[0015] Figure 3 shows a detailed cross-section of the rotor. Figure 4 shows a detailed external view of the rotor. Figure 5 shows a detailed internal view of the rotor carrier without the laminate.

[0016] In the illustrated rotor, a filler material 4 is placed between the outside of the laminate 1 and the inside of the carrier 3, filling at least partially the gap between the laminate 1 and the carrier 3. The filler material 4, for example, made of adhesive, prevents the carrier 3 from contacting the laminate 1 and generating rattling noises during operation. The carrier 3 has a filling opening 5 extending radially for injecting the filler material 4. To facilitate the injection of the filler material 4, the filling opening 5 may widen outward from the carrier 3, for example, by having a funnel-shaped portion, particularly a conical portion.

[0017] In the rotor manufacturing process, after the laminate 1 is inserted into the carrier 3, the filler material 4 is injected into the gap between the laminate 1 and the carrier 3 through these filling openings 5. Figure 5 shows the carrier 3 in cross-section with the laminate 1 omitted, and the interior is filled with the filler material 4. The filler material 4 is usually evenly distributed in all directions from the filling openings 5, forming a nearly disc-like shape as shown in Figure 5.

[0018] The carrier 3 may have a notch 6 on its axial end face, which extends from the inside to the outside of the carrier 3. As soon as the filler 4 is visible in this notch 6, the injection of the filler 4 through the filling opening 5 closest to the notch 6 can be stopped. In the region of the notch 6, the distance between the edge of the carrier 3 and the filling opening 5 is minimized, so the filler 4 usually first appears in the region of the notch 6 from the gap between the laminate 1 and the carrier 3. This prevents the filler 4 from leaking elsewhere by stopping the filling process.

[0019] In the illustrated embodiment, a plurality of filling openings 5, for example 6 to 8 filling openings 5, are evenly arranged in the circumferential direction on the carrier 3. Each of these filling openings 5 is associated with a notch 6 located on the axial end face of the carrier 3. When there are a plurality of filling openings 5 each associated with a notch 6, the injection of the filling material 4 into all the filling openings 5 can be stopped at the time when the filling material 4 is visually recognized in any of the notches 6. However, when the filling material 4 enters the notch 6, better results can be obtained if only the pouring from the closest filling opening 5 is stopped. Thereby, the filling amount can be adjusted to match the gap width that is non-uniform in the circumferential direction.

[0020] The edge of the carrier 3 has a minimum distance from the closest filling opening 5 within the notch 6. In the illustrated embodiment, the depth of the notch 6 and its width in the circumferential direction do not exceed twice the width of the filling opening 5.

[0021] When an adhesive is used as the filling material, no additional means for securing the carrier to the laminate is required. In order to increase the mechanical load capacity, in the illustrated embodiment, the laminate 1 of sheet metal is fixed to the carrier 3 by a clamp 8. The clamp 8 surrounds the radially outer edge of the carrier 3 and presses the carrier 3 axially against the laminate 1 of sheet metal.

[0022] The laminate 1 has radially outward projections 9 between its axial ends, which form pressure surfaces against which one end of the clamp 8 abuts. Thereby, the clamp 8 grips so as to enclose the associated projection 9 acting against its pressure surface.

[0023] In the illustrated embodiment, the laminate 1 is composed of identical steel sheets within manufacturing tolerances. These annular steel sheets have projections arranged at equal intervals on the outer periphery, for example 4 to 10 projections.

[0024] To assemble the laminate 1, steel plates are stacked in groups, with steel plates within the same group overlapping at the same rotational angle, and adjacent groups being rotated relative to each other by a rotational angle (45° in the illustrated example). The protrusions 9 of adjacent groups are offset from each other, so that the interface between the first group and the second group is accessible by the clamp 8. A group may consist of, for example, 4 to 25 sheets.

[0025] To assemble the rotor, the laminate 1 is inserted into the carrier 3. The carrier 3 is provided with axially extending slots 10 into which the protrusions 9 of the laminate 1 are positioned. To facilitate the insertion of the laminate 1 into the carrier 3, the slots 10 may widen toward the distal end. In the illustrated embodiment, the slots 10 have funnel-shaped ends. As shown in Figure 5, this reduces the gap area between the carrier 3 and the laminate 1. In particular, the gap area not filled with the filler material 4 is significantly reduced. [Explanation of Symbols]

[0026] 1…Laminate 2…Permanent magnets 3… Career 4…Filling material 5… Filling opening 6...cut 8… Clamp 9…Protrusion 10... Slots

Claims

1. The device comprises an annular laminate of welded steel plates (1), a permanent magnet (2) mounted inside the laminate (1), and a carrier (3) into which the laminate (1) is inserted. A rotor for an external rotor motor, characterized in that a filler material (4) is contained in the gap between the outer surface of the laminate (1) and the inner surface of the carrier (3).

2. In claim 1, A rotor for an external rotor motor, characterized in that the filler (4) is an adhesive.

3. In claim 1 or 2, Rotor for an external rotor motor, characterized in that the carrier (3) has a radially extending filling opening (5) for injecting the filler material (4).

4. In any of claims 1 to 3, A rotor for an external rotor motor, characterized in that the carrier (3) has a notch (6) on its axial end face, and the notch (6) extends from the inside to the outside of the carrier (3).

5. In claims 3 and 4, A rotor for an external rotor motor, characterized in that the depth of the cut (6) is twice or less the width of the filling opening (5).

6. In any of claims 1 to 5, A rotor for an external rotor motor, characterized in that the carrier (3) has a slot (10) extending in the axial direction, and a clamp (8) is arranged in the slot (10) to press the laminate (1) against the carrier (3) in the axial direction.

7. In claim 6, A rotor for an external rotor motor, characterized in that the slot (10) is open at one end and widens toward the open end.

8. In claim 6 or 7, Rotor for an external rotor motor, characterized in that the carrier (3) has the filling opening (5) for injecting the filler (4) between adjacent slots (10).

9. A process for manufacturing an annular laminate (1) from a steel plate, A step of welding the steel plates of the annular laminate (1), and a step of inserting the annular laminate (1) into the carrier (3), A method for manufacturing a rotor for an external rotor motor, characterized by filling the gap between the outer surface of the annular laminate (1) and the inner surface of the carrier (3) through the filling opening (5) of the carrier (3).

10. In claim 9, During the injection of the filler material (4), it is monitored whether the filler material (4) enters a notch (6) provided on the axial end face of the carrier (3) and extending from the inside to the outside of the carrier (3). A method for manufacturing a rotor for an external rotor motor, characterized in that when the filler material (4) enters the notch (6), the injection of the filler material (4) through the filling opening (5) closest to the notch (6) is immediately stopped.

Images