DC motor and method for manufacturing a DC motor

Abstract

DC motor (1), with a permanent-magnetic inner rotor (2) mounted so as to be rotatable about a longitudinal motor axis (19) and a wound stator core (3) with pronounced inwardly directed poles (4), which are integral with a magnetic return ring (5) in the circumferential direction and separated from one another by stator slots (6), an insulating body (7) which lines the stator slots (6) and has a magnetic return ring cover (8) formed with axially parallel projections (9), which covers an axial end face of the magnetic return ring (5), wherein a winding wire (10) is wound around a respective pole (4) and guided around two projections (9) radially outward to the spatially adjacent pole, wherein each pole is assigned a projection (9), and wherein the winding wire (10) is arranged between two adjacent poles (4) and between two adjacent projections (9) radially within a circle defined by the outer contours of the projections (9). (11) runs and is contacted there,characterized in that the radially inwardly guided winding wire (10) rests against mutually facing side surfaces (12) or radial grooves (25) of two adjacent projections (9).

Description

[0001] The invention relates to a DC motor (1) with a permanent magnet inner rotor (2) rotatably mounted about a longitudinal motor axis (19) and a wound stator core (3) with pronounced inwardly directed poles (4) which are integrally formed with a backplate ring (5) in the circumferential direction and separated from each other by stator slots (6), an insulating body (7) which lines the stator slots (6) and has a backplate ring cover (8) formed with axially parallel projections (9) which covers an axial end face of the backplate ring (5), wherein a winding wire (10) is wound around each pole (4) and guided radially outwards around two projections (9) to the spatially adjacent pole, each pole being assigned a projection (9). The invention further relates to a method for such a DC motor.

[0002] External stators with pronounced poles can be single-piece or multi-piece. In multi-piece stators, the poles can be wound individually from the outside, for example, using a flyer. However, the multiple interruptions in the magnetic circuit significantly reduce efficiency; therefore, stators are often manufactured as single pieces along the direction of the magnetic field lines. Single-piece stators can consist of a stack of laminations or pressed metal powder; they are generally wound using a needle winder. This requires a hollow winding needle through which the winding wire is guided. The winding needle has a minimum diameter depending on the wire diameter. For reliable manufacturing, a minimum distance between the winding needle and stator components must also be maintained. For this reason, not all geometries that would be physically possible or desirable from an assembly perspective can be realized due to manufacturing limitations.

[0003] DE 10 2016 226 200 A1 discloses a DC motor with a permanent magnet inner rotor rotatably mounted about a longitudinal axis of the motor and a wound stator core with pronounced inwards-facing poles which are integrally formed with a backplate ring in the circumferential direction and separated from each other by stator slots, an insulating body which lines the stator slots and has a backplate ring cover formed with axially parallel projections which covers an axial end face of the backplate ring, wherein a winding wire is wound around each pole.

[0004] From DE 10 2010 049 620 A1, a DC motor is known with a permanent magnet inner rotor rotatably mounted about a longitudinal axis of the motor and a wound stator core with pronounced inwards-facing poles, which are integrally formed with a back-end ring in the circumferential direction and separated from each other by stator slots, an insulating body which lines the stator slots and has a back-end ring cover formed with axially parallel projections, which covers an axial end face of the back-end ring, wherein a winding wire is wound around each pole.

[0005] The object of the invention is therefore to ensure process-reliable manufacturing, simple assembly and good efficiency in a DC motor of the generic type.

[0006] This problem is solved according to the invention by the features of claim 1 and method claim 13.

[0007] Since the winding wire (10) runs radially between two adjacent poles (4) within a circle (11) defined by the outer contours of the projections (9) and is contacted there, a terminal assembly can be easily mounted without the risk of short circuits. Short circuits could occur, for example, between the terminal assembly and a motor housing, which is usually at ground potential. Conventional needle-wound stators do not have sufficient installation space to route a winding wire radially inwards, then twice at a right angle with sufficient spacing, and then radially outwards again. Therefore, the contact unit is often positioned far forward axially or radially upwards. To provide sufficient space for further assembly, the radially inward-directed winding wire (10) is designed to rest against the facing side surfaces (12) of two adjacent projections (9).

[0008] Further developments of the invention are described in more detail in the dependent claims. In particular, it is provided that the winding wire (10) runs radially further inwards by at least one wire diameter between two adjacent poles (4) and between two adjacent projections (9) than the wire sections (wire feed section 81 and wire discharge section 82) that are guided around the outside of the projections (9).

[0009] To provide sufficient space for further assembly, the radially inwardly directed winding wire (10) is designed to have a maximum spacing of one winding wire diameter. This leaves sufficient distance between the radially extending wire sections to allow a tangentially extending wire section to run freely.

[0010] A further development of the invention consists in the fact that the return ring cover (8) has open recesses (21) in the axial direction between the projections (9). These recesses serve to ensure a reliable connection of the winding wire (10) to a contact unit.

[0011] Advantageously, axial bearing surfaces (22) for the winding wire (10) are formed between the projections (9) and the recesses (21). These serve to ensure optimal routing of the winding wire (10).

[0012] Process reliability and the risk of short circuits are further optimized by the provision of axial grooves (24) in the contact surfaces (22) and / or radial grooves (25) in the projections (9) for receiving wire sections. This allows the winding wire to be laid in an organized manner and without contact between two adjacent wire sections.

[0013] The routing of the winding wire (10) is further improved by having a wire feed section (81) of the same winding wire (10) rest on a first support surface (22) and a subsequent wire discharge section (82) rest on a second support surface (23).

[0014] Furthermore, a contact section of the winding wire (10) between two adjacent poles (4) is electrically connected to the contact projection (13) of a busbar (14). This contact projection (13) is designed to fit between the radially extending winding wire sections. For contact reliability, the contact projection (13) must have a minimum width and must not damage or weaken the radially extending winding wire sections. The busbar connects the coils (39) of a phase to each other for electrical connection at a common terminal (32).

[0015] Hook-shaped contact projections (13) have proven to be useful, as they can be easily joined and electrically connected to exposed winding wire sections.

[0016] It is usefully provided that the contact protrusions (13) are each partially arranged in the area of ​​a free space (21).

[0017] The electrical connection can be most reliably established by a weld. This provides both a good electrical and a stable mechanical connection between the contact hooks (17) and the contact section (20) of the winding wire (10).

[0018] According to a further feature of the invention, the insulating body (7) does not have any wire deflection means around which the winding wire (10) is guided radially inwards. The winding wire would have to be guided around such wire deflection means sequentially during the winding process, which would be time-consuming. It would be more advantageous to position the contact sections (20) radially inwards in a single operation.

[0019] The invention is also solved by a method according to claim 13, in particular by the following method steps: a) providing a stator core (3) provided with an insulating body (7) and a needle winding machine; b) inserting the stator core into the needle winding machine; c) striking a winding wire against a fixed stop point on the stator or on a tool holder; d) guiding the winding wire (10) radially inwards from the stop point between two projections (9) of the insulating body (7); e) winding a coil around a pole (4); f) guiding the winding wire (10) radially outwards between two projections; g) guiding the winding wire (10) around a tool-fixed deflecting element radially outside the return ring; h) repeating steps d to g until the stator is wound and striking the winding wire against a fixed stop point on the stator or on a tool holder; i) Retraction of the tool-fixed deflection means;j) radially deforming the radially outer winding wire sections inwards, until they reach an area within the return ring; k) placing contact sections of a contact unit onto the exposed winding wire sections; i) welding the contact sections to the winding wire sections.

[0020] Exemplary embodiments of the invention are explained in more detail below with reference to the drawing. The drawing shows: Fig. 1 an insulating body, Fig. 2 a stator core, Fig. 3 an insulating body mounted on the stator core, Fig. 4 a stator equipped with a winding, Fig. 5 a top view of Fig. 4, Fig. 6 an addition of Fig. 5 with wire laying aids, Fig. 7 a spatial representation of Fig. 6, Fig. 8 a sectional view of a DC motor, Fig. 9 a representation of a bending process, Fig. 10 a spatial representation of the bending process, Fig. 11 a spatial representation of the wire path after the bending process and Fig. 12 a mounted stator with connection unit.

[0021] Fig. Figure 1 shows an insulating body 7 for a nine-pole stator, with thin-walled slot linings 29, a back-ring cover 8 which is hollow-cylindrical in its basic form and has recesses 21 and projections 9 on its axial surface opposite the slot linings 29. Between the recesses 21 and the projections 9, first bearing surfaces 22 and second bearing surfaces 23 are formed in a stepped manner. The first bearing surfaces 22 have axial grooves 24, and the second bearing surfaces 23 have radial grooves 25. These serve for the defined routing of a winding wire, whereby contact between individual wire sections should be avoided as far as possible. One side surface 12 of the projections has no groove structure. The slot linings 29 also have grooves 27, which ensure the orderly routing of the winding wire.Between the groove linings 29 and the projections 9, wire guide grooves 26 run parallel to a longitudinal motor axis 19. Guide grooves 28 are formed on the radially inner side of the projections 9, which serve to receive and guide a contact unit. The guide grooves 28 also have axial stop surfaces 35, which are also helpful for correct orientation during installation.

[0022] Fig. Figure 2 shows a stator core 3, consisting of a stack of magnetically conductive laminations insulated from one another. In the example shown, the stator core comprises nine pronounced poles 4 directed inwards towards the motor's longitudinal axis 19. Pole shoes 42 are located at the inner end of each pole, widening the pole area. The pole width is limited by the width of a winding needle and its required freedom of movement during stator winding. The poles 4 define stator slots 6, which serve as winding receiving spaces. The poles 4 are integrally formed with a backing ring 5 within a single lamination. Clamping tongues 31 are partially stamped onto the radial outer surface of the backing ring 5; these serve to secure the poles in a motor housing.

[0023] Fig. Figure 3 shows a stator 30, consisting of a stator core 3, an axially mounted insulating body 7, and an insulating cap 34 mounted on the axially opposite side, which also serves as a slot lining and back-ring cover. The motor's longitudinal axis 19 is also shown.

[0024] Fig. Figure 4 shows a stator 30 according to Fig. 3 with additional winding by a winding wire 10. The insulating cap 34, the stator core 3 with the backing ring 5 and the poles 4, the insulating body 7 with the backing ring cover 8, the first contact surfaces 22, the recesses 21, and the projections 9 are shown in detail. The winding wire 10 is wound around each pole 4, then routed radially outwards from a first stator slot 6, guided around two adjacent projections 9, and then radially inwards to an adjacent pole in an adjacent stator slot. The remaining poles are wound in the same manner. The motor's longitudinal axis 19 is also shown.

[0025] Fig. 5 shows a top view of Fig. 4, with the stator 30, with the insulating body 7, the poles 4, the winding wire 10, the clearances 21 and the projections 9.

[0026] Fig. 6 shows an addition to Fig. 5 with the stator 30, wire laying aids 33, which consist of tool-resistant deflection pins that are removed after winding. Also visible are the insulating body 7, the poles 4, the winding wire 10, the clearances 21 and the projections 9.

[0027] Fig. Figure 7 shows a spatial representation of Fig. 6, with the stator 30, the wire laying aids 33, the insulation cap 34, the stator core 3, the insulating body 7, the winding wire 10, the clearances 21, the reverse ring cover 8, the motor longitudinal axis 19 and the projections 9.

[0028] Fig. Figure 8 shows a sectional view of a DC motor 1 with a motor housing 15 and an inner rotor 2. Also visible is the stator 30, with the insulating body 7, the winding wire 10, the cutouts 21, coils 39, and projections 9. The radially outward-projecting parts of the winding wire 10 are shown only to illustrate the geometric relationships.

[0029] The Fig. Figures 4 to 8 show an intermediate state of the stator 30 during manufacturing.

[0030] Fig. 9 and Fig. Figure 10 shows illustrations of a bending process and the spatial shape of the stator winding 40, which consists of a plurality of coils 39. Several bending dies 36, of which only one is shown, with two wire forming contours 37 and a recess 38, are moved radially inwards (see arrow) and thereby deform the winding wire 10 in the region of the radially outward-facing sections such that it runs radially within a circle 11 defined by the outer contours of the projections between two adjacent poles (not shown) and between two adjacent projections (not shown). This region of the winding wire serves as a contact section 20. A wire feed section 81 and a wire discharge section 82 are connected to each contact section 20. The wire feed section 81 runs axially closer to the stator core 3 than the wire discharge section 82.The wire feed section 81 and the wire discharge section 82 are guided around the outside via a projection 9.

[0031] Fig. Figure 11 shows a spatial representation of the path of the winding wire 10 after the bending process. Between two adjacent poles, the winding wire 10 runs such that it originates from a coil wound around a first pole (see Figure 11). Fig. 9) from a stator slot, first axially and then radially outwards, then tangentially, radially inwards, again tangentially, radially outwards, tangentially and again radially inwards and to the adjacent pole, where it leads to a second coil (see Fig. 9) forms. The area between a wire discharge section 82 and a wire feed section 81 forms a wire connection 18 between the coils of spatially adjacent poles. The contact section 20 is located between the wire discharge section 82 and the wire feed section 81.

[0032] Fig. Figure 12 shows a mounted stator 30, with the insulating cap 34, the stator core 3, the insulating body 7, and a contact unit 16. The contact unit 16 consists of busbars with hook-shaped contact projections 13 (contact hooks 17). Due to the orientation of the contact projections 13, the contact unit 16 can be mounted axially onto the stator 30. The contact projections 13 are spatially aligned with the recesses 21. The recesses are dimensioned so that a welding gun can easily reach both sides of the contact projections 13. Recesses 41 on the contact unit 16 serve the same purpose. Each busbar also has terminals 32 through which the winding is energized. Reference symbol list 1 DC motor 2 inner rotors 3 Stator core 4 pole 5 Return ring 6 Stator slot 7 insulating body 8 Backing ring cover 9 lead 10 winding wire 11th district 12 side surface 13 Contact advantage 14 busbar 15 Motor housings 16 contact units 17 contact hooks 18 wire connection 19 Engine longitudinal axis 20 Contact section 21 Free savings 22 first contact surface 23 second support surface 24 Axial groove 25 radial groove 26 Wire guide groove 27 groove 28 guide groove 29 Groove lining 30 Stator 31 Clamping tongue 32 Connection flag 33 Wire laying aid 34 Insulation cap 35 axial stop surface 36 bending dies 37 Wire forming contour 38 Exclusion 39 coil 40 Stator winding 41 In-depth study 42 Pole shoe 81 Wire feed section 82 Wire discharge section

Claims

[1] DC motor (1), comprising a permanent magnet inner rotor (2) rotatably mounted about a longitudinal axis (19) of the motor and a wound stator core (3) with pronounced inwardly directed poles (4) which are integrally formed in the circumferential direction with a back-end ring (5) and separated from each other by stator slots (6), an insulating body (7) which lines the stator slots (6) and has a back-end ring cover (8) formed with axially parallel projections (9) which covers an axial end face of the back-end ring (5), wherein a winding wire (10) is wound around each pole (4) and guided radially around two projections (9) to the spatially adjacent pole,wherein each pole is assigned a projection (9) and wherein the winding wire (10) runs radially within a circle (11) defined by the outer contours of the projections (9) between two adjacent poles (4) and between two adjacent projections (9) and is contacted there, , characterized by , that the radially inwardly guided winding wire (10) rests against mutually facing side surfaces (12) or radial grooves (25) of two adjacent projections (9). [2] DC motor according to claim 1, characterized by , that the winding wire (10) runs radially further inwards by at least one wire diameter between two adjacent poles (4) and between two adjacent projections (9) than the wire sections (wire feed section 81 and wire discharge section 82) guided around the projections (9). [3] DC motor according to claim 1, characterized by, that the radially inwardly guided winding wire (10) has a distance of only a maximum of one winding wire diameter to the respective side surface (12) or radial groove (25). [4] DC motor according to claim 1, 2 or 3, characterized by , that the back-ring cover (8) has open recesses (21) between the projections (9) in the axial direction. [5] DC motor according to claim 4, characterized by , that axial bearing surfaces (22) for the winding wire (10) are formed between the projections (9) and the recesses (21). [6] DC motor according to claim 5, characterized by , that axial grooves (24) and / or radial grooves (25) for receiving wire sections are present in the bearing surfaces (22) and / or in the projections (9). [7] DC motor according to claim 5 or 6, characterized by, that each wire feed section (81) of the same winding wire (10) rests on a first support surface (22) and a subsequent wire discharge section (82) rests on a second support surface (23). [8] DC motor according to at least one of claims 1 to 7, characterized by , that a contact section (20) of the winding wire (10) between two adjacent poles (4) is electrically connected to a contact projection (13) of a busbar (14). [9] DC motor according to claim 8, characterized by , that the contact projection (13) is hook-shaped. [10] DC motor according to claim 8 or 9, characterized by , that the contact projection (13) is partially located in the area of ​​a free space (21). [11] DC motor according to at least one of the preceding claims, characterized by, that the contact section (20) of the winding wire (10) between two adjacent poles (4) is contacted by a welded connection. [12] DC motor according to at least one of the preceding claims, characterized by , that the insulating body (7) has no wire deflection means by which the winding wire (10) is guided radially inside. [13] Method for manufacturing a DC motor (1) comprising a permanent magnet inner rotor (2) rotatably mounted about a motor longitudinal axis (19) and a wound stator core (3) with pronounced inwardly directed poles (4) which are integrally formed in the circumferential direction with a back-end ring (5) and separated from each other by stator slots (6), an insulating body (7) which lines the stator slots (6) and has a back-end ring cover (8) formed with axially parallel projections (9) which covers an axial end face of the back-end ring (5), wherein a winding wire (10) is wound around each pole (4) and guided radially around two projections (9) to the spatially adjacent pole, wherein each pole is assigned a projection (9), characterized byThe following process steps are performed: a) providing a stator core (3) with an insulating body (7) and a needle winding machine; b) inserting the stator core into the needle winding machine; c) striking a winding wire against a fixed stop point on the stator or on a tool holder; d) guiding the winding wire (10) radially inwards from the stop point between two projections (9) of the insulating body (7); e) winding a coil around a pole (4); f) guiding the winding wire (10) radially outwards between two projections; g) guiding the winding wire (10) around a tool-fixed deflector radially outside the return ring; h) repeating steps d to g until the stator is wound and striking the winding wire against a fixed stop point on the stator or on a tool holder; i) retracting the tool-fixed deflectors;j) radially deforming the radially outer winding wire sections inwards, until they reach an area within the return ring; k) placing contact sections of a contact unit onto the exposed winding wire sections; i) welding the contact sections to the winding wire sections.

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