Rotor for an outer rotor motor
By using shaft hub connection and welding technology in the outer rotor motor, the stack of laminated sheets is connected to the bracket, which solves the problem of unstable torque transmission, realizes an efficient and low-cost rotor design, and improves the performance of the motor.
Patent Information
- Application Number
- CN202421709365.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Priority Date
- 2023-07-21
- Filing Date
- 2024-07-18
- Publication Date
- 2025-08-26
- Estimated Expiration
- 2034-07-18
AI Technical Summary
The prior art is difficult to achieve reliable and cost-effective torque transfer from the stack of laminated sheets to the brackets in outer rotor motors.
By using a hub connection between the stack of the laminate sheet and the bracket, the stack of the laminate sheet is connected to the bracket by using axially extending protrusions and welding techniques, and the bracket is connected around the stack in part, using paired protrusions and slot structures to enhance mechanical stability and reduce material use.
Reliable torque transmission is achieved, while reducing the quality and material cost of the rotor, and improving the efficiency and stability of the motor.
Smart Images
Figure CN223273924U_ABST
Abstract
Description
Technical Field
[0001] The utility model is based on a rotor for an external rotor motor. Background Art
[0002] In such a rotor for an outer rotor motor, the stack of laminated sheets forming the short-circuit rings must be connected to a carrier having a hub for the shaft. Utility Model Content
[0003] The object of the present invention is to show a way in which this can be done cost-effectively while ensuring a reliable transmission of torque from the stack of laminate sheets to the support.
[0004] This object is achieved by a rotor having the following features:
[0005] A rotor for an outer rotor motor, the rotor comprising:
[0006] A stack of ferromagnetic steel sheets,
[0007] a permanent magnet fixed to the inner side of the stack, and
[0008] a bracket having a hub for an axle and attached to the stack,
[0009] The bracket is connected to the stack via a hub connection.
[0010] According to the invention, the stack of laminated sheets is connected to the bracket by means of a hub connection.The ferromagnetic steel sheets are preferably made of electrical steel, ie soft magnetic steel, such as silicon steel.
[0011] An advantageous further development of the present invention provides for welding together the metal sheets forming the stack of short-circuit rings. In this way, although the short-circuit rings consist of individual sheets, they are preassembled to form an easily handled assembly. However, the sheets can also be joined together in other ways, such as by stamping or using an interlocking system. The individual sheets of the sheet stack can be annular sheets or each can form only one ring segment.
[0012] Another advantageous further development of the invention provides that the sheets of the stack are connected by means of several welds, which extend in the axial direction and are preferably arranged on the outside of the stack of laminated sheets. Welding usually impairs the magnetic properties of the steel sheets. In the material melting region of the weld, the microstructure is typically adversely altered. It is therefore advantageous that the volume of the weld in the sheet stack is relatively small, so that the magnetic properties of the sheet stack are only slightly impaired. For example, the weld can be arranged in a protrusion on the outside of the stack of laminated sheets, in particular completely in a protrusion on the outside of the stack of laminated sheets. Such a protrusion can extend in the axial direction on the outside of the stack of laminated sheets and contribute to the connection of the stack of laminated sheets to the hub of the support.
[0013] Another advantageous further development of the invention provides that the hub connection of the laminate stack to the bracket is fixed by means of projections of the laminate stack which extend in the axial direction on the outside of the laminate stack and engage in slots of the bracket.
[0014] Another advantageous further development of the present invention provides for a bracket to carry a plurality of retainers on its outer side, which connect the stack of laminated sheets to the bracket. The retainers can engage around the stack of laminated sheets at one end and around the edge of the bracket at the other end, thereby preventing the stack of laminated sheets from moving axially relative to the bracket. For example, the retainers can be arranged on axially extending protrusions of the stack of laminated sheets. The bracket can be welded to the stack of laminated sheets. This has the advantage of increasing rotor stability.
[0015] Another advantageous further development of the present invention provides for the bracket to surround the stack of laminated sheets over only a portion of its axial length. Since the steel sheets of the stack are welded to one another, a shaft-hub connection over a portion of the axial length of the stack of laminated sheets is sufficient to transmit torque from the stack of laminated sheets to the bracket. This has the advantage of reducing the mass of the rotor and thus increasing the efficiency of the motor. For example, good results can be achieved if the bracket surrounds the stack of laminated sheets over 20% to 50% of its length.
[0016] Another advantageous further development of the present invention provides for the bracket to have a pair of protrusions extending axially outside the sheet stack, with a slot formed between the protrusions. This advantageously reduces the mass of the rotor, thereby improving the efficiency of the motor. Preferably, the protrusions have a raised portion at their edges facing the slots, i.e., they extend further radially at these edges. This advantageously improves the mechanical stability of the torque transmission from the stack to the bracket.
[0017] The number and width of the paired protrusions can be freely selected within a wide range. For example, a bracket with three to six pairs of protrusions can achieve a reliable hub-shaft connection. In one embodiment of the present invention, the distance between adjacent pairs of protrusions is at least twice the width of the slot, and can be, for example, five to ten times the width of the slot. In this way, the mass of the bracket can be advantageously kept low while still achieving a reliable hub-shaft connection between the bracket and the stack of sheets.
[0018] Another advantageous further development of the present invention provides that the stack of sheets has grooves on its inner side, which extend in the axial direction and in which permanent magnets are arranged. Thus, the permanent magnets can advantageously stabilize the stack of laminated sheets. For example, the permanent magnets can be glued into the grooves. The protrusions on the outside of the stack of laminated sheets can, for example, be arranged opposite the grooves and thus compensate for the radial thickness of the stack of laminated sheets that is locally reduced due to the grooves. However, not every groove necessarily has a protrusion opposite it.
[0019] Advantageously, the metal sheets of the stack are welded together.
[0020] Advantageously, the plates of the stack are welded together by a plurality of weld seams extending in the axial direction on the outside of the stack.
[0021] Advantageously, the stack has a first projection on its outer side, which extends in the axial direction and engages in a slot in the bracket.
[0022] Advantageously, the weld seam extends in the first projection.
[0023] Advantageously, the stack carries on its outer side holders connecting the stack to the support.
[0024] Advantageously, the support surrounds the stack over only a portion of its axial length.
[0025] Advantageously, the support surrounds the stack over 20% to 50% of the length of the stack.
[0026] Advantageously, the bracket includes a pair of second protrusions extending in the axial direction outside the stack, and the slot is formed between the pair of second protrusions.
[0027] Advantageously, the distance between adjacent pairs of second protrusions of the bracket is at least twice the width of the slot.
[0028] Advantageously, the distance between adjacent pairs of second protrusions of the bracket is five to ten times the width of the slot.
[0029] Advantageously, the second projection of the bracket has a raised portion on its edge facing the slot.
[0030] Advantageously, each of the first protrusions of the stack is arranged opposite one of the permanent magnets.
[0031] Advantageously, the first protrusion of the stack is positioned opposite only every other permanent magnet of the permanent magnets on the outside of the stack. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Further details and advantages of the present invention are explained with reference to the accompanying drawings.
[0033] Figure 1 The rotor for the external rotor motor is shown, and
[0034] Figure 2 A schematic representation of the hub connection between the sheet stack and the bracket is shown. DETAILED DESCRIPTION
[0035] Figure 1 The rotor shown in FIG has a stack 1 made of ferromagnetic steel sheets; permanent magnets 2 attached to the inside of stack 1; and a bracket 3 made of a non-ferromagnetic material attached to stack 1, with a hub for the shaft (not shown). Bracket 3 can be made of aluminum or an aluminum-based alloy, for example. The steel sheets of stack 1 are electron beam-formed (i.e., soft magnetic steel, such as silicon steel) and are stacked one on top of the other in the axial direction. Therefore, the planes of the individual sheets extend perpendicular to the axial direction.
[0036] The stack 1 has brackets 4 on its exterior that surround the two ends and preferably also the brackets 3. These brackets 4 can be welded to the stack. In the example shown, welds (not shown) pass through the stack of laminated sheets, thus connecting all the individual sheets of the shorting ring 1 together. However, the sheets of the stack of laminated sheets can also be mechanically connected to each other in other ways, such as by an interlocking system or with the aid of a punching pack.
[0037] In the example shown, the stack 1 has four brackets 4, and the sheets of the stack 1 are welded together by four welds 5. The number of brackets 4 and welds 5 can vary. Good results are generally achieved with three to six brackets 4 and welds 5. More brackets increase the manufacturing difficulty; fewer brackets make the stack 1 more difficult to handle.
[0038] In the embodiment shown, the brackets 4 are arranged on projections 6 of the stack 1, which extend in the axial direction outside the stack of laminated sheets. Advantageously, the welding thus impairs the magnetic properties of the sheets only to a negligible extent, in particular if the weld seam 5 extends only in the projections 6 inside the stack 1.
[0039] The protrusion 6 on the outside of the stack 1 also serves as a hub-and-shaft connection between the stack 1 and the support 3 . Figure 2 This shaft-hub connection is shown in . Figure 2 A schematic cross-sectional view of the stack 1 and the rotor support 3 is shown. The protrusion 6 of the short-circuit ring 1 (for simplicity, it is Figure 2 The bracket 3 is shown without a bracket in the figure and engages in the slot of the bracket 3 and thus enables the torque to be transmitted from the stack 1 to the bracket 3. The slot of the bracket 3 is formed between the protrusions 8 of the bracket 3, which extend in the axial direction outside the stack 1. Therefore, the slot is formed by the paired protrusions 8 of the bracket 3, which is particularly Figure 1 It can be seen in.
[0040] The projection 8 of the bracket 3 extends only over a portion of the axial length of the stack 1, for example, over 20% to 50% of the axial length of the stack 1. In this way, a corrugated hub connection between the stack 1 and the bracket 3 can be realized with low material costs and advantageously low weight.
[0041] The projection 8 of the bracket 3 has a raised portion 9 on its edge adjacent to the projection of the stack, ie the projection extends further in radial direction on this edge. The raised portion 9 is a thickening of the projection 8 and increases the mechanical stability of the torque transmission.
[0042] The distance between adjacent pairs of projections 8 of the bracket 3 is considerable, thereby saving material. In the example shown, the distance is greater than twice the width of the slot and is five to ten times the width of the slot.
[0043] like Figure 2 As shown, each of the protrusions 6 of the stack 1 is arranged opposite one of the permanent magnets 2. The permanent magnets 2 are glued into the grooves inside the stack 1. However, not every permanent magnet 2 faces the protrusion of the stack 1. Figure 1 As shown, the permanent magnets 2 have more protrusions 6 than the stack 1 .
[0044] List of Reference Numerals
[0045] 1 stack
[0046] 2 permanent magnets
[0047] 3 brackets
[0048] 4 brackets
[0049] 5. Welds
[0050] 6. Protrusion of stack
[0051] 8 bundles of protrusions
[0052] 9. Rise to the upper part
Claims
1. A rotor for an outer rotor motor, the rotor having a stack of ferromagnetic steel sheets (1), a permanent magnet (2) fixed to the inner side of the stack (1), and a bracket (3) having a hub for an axle and attached to the stack (1), It is characterized by: The bracket (3) is connected to the stack (1) via a hub connection.
2. The rotor according to claim 1, characterized in that The metal sheets of the stack (1) are welded together.
3. The rotor according to claim 2, characterized in that The plates of the stack (1) are welded together by a plurality of weld seams (5) extending in an axial direction on the outside of the stack (1).
4. The rotor according to claim 3, characterized in that The stack (1) has a first protrusion (6) on its outer side, which extends in the axial direction and engages in a slot in the bracket (3).
5. The rotor according to claim 4, characterized in that The weld seam (5) extends in the first projection (6).
6. The rotor according to any one of claims 1 to 5, characterized in that The stack (1) carries a holder (4) on its outer side, which connects the stack (1) to the support (3).
7. The rotor according to any one of claims 1 to 5, characterized in that The support (3) surrounds the stack (1) over only a portion of the axial length of the stack (1).
8. The rotor according to claim 7, characterized in that The support (3) surrounds the stack (1) over 20% to 50% of the length of the stack (1).
9. The rotor according to claim 4, characterized in that The bracket (3) comprises a pair of second protrusions (8), the pair of second protrusions extending in the axial direction outside the stacked body (1), and the narrow slot is formed between the pair of second protrusions.
10. The rotor according to claim 9, characterized in that The distance between adjacent pairs of second protrusions (8) of the bracket (3) is at least twice the width of the slot.
11. The rotor according to claim 10, characterized in that The distance between adjacent pairs of second protrusions (8) of the bracket (3) is five to ten times the width of the slot.
12. The rotor according to claim 9 or 10, characterized in that The second protrusion (8) of the bracket (3) has a raised portion (9) on its edge facing the slot.
13. The rotor according to claim 4, characterized in that Each of the first protrusions (6) of the stack (1) is arranged opposite to one of the permanent magnets (2).
14. The rotor according to claim 4, characterized in that The first protrusion (6) of the stack (1) is positioned on the outside of the stack (1) so as to be opposite only every other permanent magnet among the permanent magnets (2).