MOLDING-ON TOOL AND METHOD FOR PRODUCING A ROTOR

Abstract

A molding-on tool for producing a rotor, the rotor having a plurality of stacks, which are stacked one over the other in the axial direction and each have a magnet carrier and a plurality of magnets fastened thereto. Plastic is molded onto the magnets in order to fix the position on the magnet carrier, the molding-on tool having at least two molding-on plates, which are provided for feeding plastic in order to mold plastic onto the magnets.

Claims

1. A molding-on tool for producing a rotor, the rotor having a plurality of stacks, which are stacked one over the other in an axial direction and each have a magnet carrier and a plurality of magnets fastened thereto, the molding-on tool comprising: at least two molding-on plates, configured for feeding plastic in order to mold plastic onto the magnets to fix a position on the magnet carrier.

2. The molding-on tool according to claim 1, wherein one of the at least two molding-on plates is formed as a sprue plate arranged as an outermost molding-on plate on an axial side of all the stacks, and the other of the at least two molding-on plates is formed as an intermediate plate arranged as an inner molding-on plate inside an entirety of the stacks.

3. The molding-on tool according to claim 1, wherein the molding-on tool has its own molding-on plate for each stack.

4. The molding-on tool according to claim 1, wherein the molding-on plates each have a plastic guiding device for guiding the plastic and/or a plastic dispensing device for feeding the plastic to the stack associated with the molding-on plate.

5. The molding-on tool according to claim 4, wherein the plastic dispensing device is matched to the position of the magnets of the stacks to be molded in such a way that the magnets can be molded from behind.

6. A method for producing a rotor, the method comprising: in one step equipping a magnet carrier with magnets and stacking a plurality of magnet carriers equipped with magnets one over the other in an axial direction, in another step arranging at least one molding-on plate between two magnet carriers of the plurality of magnet carriers, and in a further step feeding plastic to the molding-on plate in order to mold the magnets associated with the magnet carrier onto the magnet carrier at a magnet carrier associated with the molding-on plate.

7. The method according to claim 6, further comprising: stacking the plurality of magnet carriers equipped with magnets one over the other in a same orientation in a circumferential direction.

8. The method according to claim 6, wherein the plastic fed to the molding-on plate predominantly or only molds the magnets of the magnet carrier associated with the molding-on plate onto the respective magnet carrier.

9. The method according to claim 6, further comprising: molding the stack of magnet carriers equipped with magnets with plastic from top to bottom in a direction of gravity.

10. The method according to claim 6, wherein the molding-on plate is fed the plastic from the magnet carrier adjacent on one side of the molding-on plate and/or the molding-on plate feeds the plastic to the magnet carrier adjacent on the other side of the molding-on plate via a plastic dispensing device.

11. A molding-on tool for producing a rotor, comprising: at least two molding-on plates configured for feeding plastic to mold plastic onto magnets to fix a position on a magnet carrier of the rotor, wherein the rotor has a plurality of stacks of magnet carriers, which are stacked one over the other in an axial direction, wherein one of the at least two molding-on plates is arranged as an outermost molding-on plate on an axial side of all the stacks, and the other of the at least two molding-on plates is arranged as an inner molding-on plate inside an entirety of the stacks.

12. The molding-on tool according to claim 11, wherein each of the at least two molding-on plates has a plastic guiding device for guiding the plastic and a plastic dispensing device for feeding the plastic to the stack associated with the molding-on plate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The disclosure is explained below with the aid of drawings. In the figures:

[0022] FIG. 1 shows a perspective view of a molding-on tool according to the disclosure with a plurality of molding-on plates for producing a rotor from a plurality of stacks,

[0023] FIG. 2 shows a molding-on plate in the form of an intermediate plate, and

[0024] FIG. 3 shows a perspective view of a section of a stack of the rotor.

DETAILED DESCRIPTION

[0025] The figures are only schematic in nature and serve only for understanding the disclosure. The same elements are provided with the same reference symbols.

[0026] FIG. 1 shows a molding-on tool 1 according to the disclosure for producing a rotor 2 for an electric motor. The rotor 2 is made up of a plurality of stacks 3. The rotor 2 has a plurality of stacks 3 stacked one over the other in the axial direction. The stacks 3 each have a magnet carrier 4 and a plurality of magnets 5 fastened thereto (cf. FIG. 3). The magnets 5 are molded onto the magnet carrier 4 in order to fix the position. For example, the magnets 5 are molded onto the magnet carrier 4 with plastic, such as epoxy resin.

[0027] According to the disclosure, the molding-on tool 1 has at least two molding-on plates 6. The molding-on plates 6 are prepared to feed the plastic to the stacks 3 in order to mold plastic onto the magnets 5.

[0028] One molding-on plate 6 of the at least two molding-on plates 6 is formed as a sprue plate 7. The sprue plate 7 is arranged as an outermost molding-on plate 6 on an axial side of all stacks 3. The sprue plate 7 is the uppermost molding-on plate 6 in the direction of gravity. The sprue plate 7 allows the plastic to be introduced into the molding-on tool 1 and distributed from there. In the embodiment shown, the plastic can be introduced from a press (not shown), in particular a transfer press, via openings 8. The plastic introduced can be distributed in the sprue plate 7 via a plastic guiding device 9. In the embodiment shown, the plastic guiding device 9 is designed as a channel system or path network of sprue channels. In the embodiment shown, the sprue channels are connected to each other in the manner of a snowflake. This means that the sprue channels branch radially outward and in the circumferential direction of the sprue plate 7.

[0029] The plastic can flow through the plastic guiding device 9 to a plastic dispensing device 10, in the form of molding ports/molding nozzles in the embodiment shown. From the plastic dispensing device 10, the plastic is fed to the first stack 3a so that the magnets 5 of the first stack 3a, which are arranged in magnet recesses 14, are molded onto the magnet carrier 4 of the first stack 3a. The plastic dispensing device 10 is arranged to guide the plastic to suitable molding-on points 13. The molding-on points 13 are selected such that the magnets 5 are molded from behind. That is, the plastic dispensing device 10 is arranged to mold the back of the magnets 5. The position of the molding nozzles is thus matched to the position of the magnets 5 to be molded. The injection pressure pushes the magnets 5 into the desired position. In particular, the magnets 5 are molded in a targeted manner so that they abut on the outside. For example, the magnets 5 are thus molded from radially inside. Each molding nozzle can, for example, be arranged radially further inwards than a magnet 5 associated with it.

[0030] One molding-on plate 6 of the at least two molding-on plates 6 is formed as an intermediate plate 11. Preferably, the molding-on tool 1 can have a plurality of molding-on plates 6. In the embodiment shown, one intermediate plate 11 is arranged between each of two stacks 3. The intermediate plate 11 has a plastic dispensing device 12. In the embodiment shown, the plastic dispensing device 12 is formed by a plurality of molding nozzles, for example in the form of through holes, which are arranged distributed over the circumference of the intermediate plate 11. In particular, the molding nozzles can be arranged in an evenly distributed manner. The plastic dispensing device 12 is arranged to guide the plastic to the suitable molding-on points 13. That is, the plastic dispensing device 12 is arranged to mold the back of the magnets 5. The injection pressure pushes the magnets 5 into the desired position. In particular, the magnets 5 are molded in a targeted manner so that they abut on the outside. For example, the magnets 5 are thus molded from radially inside. Each molding nozzle can, for example, be arranged radially further inwards than a magnet 5 associated with it. The position of the molding nozzles is thus matched to the position of the magnets 5 to be molded. The intermediate plate 11 is thus designed in such a way that a melt flow analogous to the sprue plate 7 flows behind the magnets 5. From the plastic dispensing device 12, the plastic is fed to the stack 3b, 3c, 3d, 3e, 3f associated with the intermediate plate 11 so that the magnets 5 of the associated stack 3b, 3c, 3d, 3e, 3f, which are arranged in the magnet recesses 14, are molded onto the magnet carrier 4 of the associated stack 3b, 3c, 3d, 3e, 3f.

[0031] In FIG. 2, a contour of the stacks 3 is indicated. Each stack 3 has an inner toothing 15 on its radial inner side. The inner toothing 15 is arranged centrally. The inner toothing 15 allows the individual, axially stacked stacks 3 to be connected to each other in a non-rotatable manner via a shaft (not shown).

[0032] The disclosure also relates to a method for producing the rotor 2, which is explained with reference to FIG. 1. According to the disclosure, the magnet carrier 4 of one stack 3, preferably of all stacks 3, is equipped with the magnets 5 and the plurality of stacks 3, i.e., the magnet carriers 4 equipped with the magnets, are stacked one over the other in the axial direction. In another step, the molding-on plate 6, which is formed as an intermediate plate 11, is arranged between two of the magnet carriers 4. Preferably, a molding-on plate 6 in the form of an intermediate plate 11 is arranged between each pair of magnet carriers or stacks. In a further step, plastic is fed to the molding-on plate 6, preferably to the molding-on plates 6, in order to, at the magnet carrier 4 assigned to the molding-on plate 6, preferably at all magnet carriers 4 assigned in each case to a molding-on plate 6, mold the magnets 5 associated with the magnet carrier 4 onto the magnet carrier 4. Thus, the plastic fed to a molding-on plate 6 predominantly or only molds the magnets 5 of the magnet carrier 4 associated with the molding-on plate 6 onto the respective magnet carrier 4.

[0033] In the embodiment shown, the plurality of magnet carriers 4 equipped with magnets 5 are stacked one over the other in the same orientation in the circumferential direction. Alternatively, the plurality of magnet carriers 4 equipped with magnets 5 can be arranged offset in the circumferential direction by a predetermined circumferential distance, although this is not shown.

[0034] In the method according to the disclosure, the stack of magnet carriers 4 equipped with magnets 5 is molded with plastic from top to bottom in the direction of gravity. This means that the plastic melt flows through the stack in the direction of gravity. Thus, the magnets 5 are molded first in the first stack 3a, then in the second stack 3b, then in the third stack 3c, and so forth.

[0035] The plastic is introduced via the molding-on plate 6 (formed as a sprue plate 7) and the magnets 5 in the first stack 3a are molded. According to the disclosure, the plastic is then fed to each molding-on plate 6 (formed as an intermediate plate 7) from the magnet carrier 4 adjacent on one side of the respective molding-on plate 6, i.e., from the magnet carrier 4 adjacent at the top in the direction of gravity, and each molding-on plate 6 (formed as an intermediate plate 7) feeds the plastic to the magnet carrier 4 adjacent on the other side of the respective molding-on plate 6, i.e., to the magnet carrier 4 adjacent at the bottom in the direction of gravity, for example via the plastic dispensing device 12. As a result, each magnet 5 is molded in a targeted manner.

LIST OF REFERENCE SYMBOLS

[0036] 1 Molding-on tool

[0037] 2 Rotor

[0038] 3 Stack

[0039] 4 Magnet carrier

[0040] 5 Magnet

[0041] 6 Molding-on plate

[0042] 7 Sprue plate

[0043] 8 Opening

[0044] 9 Plastic guiding device

[0045] 10 Plastic dispensing device

[0046] 11 Intermediate plate

[0047] 12 Plastic dispensing device

[0048] 13 Molding-on point

[0049] 14 Magnet recess

[0050] 15 Inner toothing