JP6643386B2 - Electronically commutated DC motor and method of assembling electronically commutated DC motor - Google Patents

Description

  The present invention provides a stator with windings (2) having a stator sheet packet (3) and a cup-shaped housing (4), and a permanent magnet rotor (5) housed in the stator sheet packet (3). The invention relates to an electronically commutated DC motor (1) having a shaft (6), a plastic hub (7) and a magnetized permanent magnet (8).

  This type of DC motor is widely used and is used in various fields. They can be used in dry or wet areas, where they are filled with liquid or exposed to liquid from outside. For example, this type of DC motor is used as a drive device for an oil pump. If the sealing requirements are high, these motors often have a cup-shaped housing. This is because it reduces the number of interfaces to be sealed. Permanent magnet rotors used in electronically commutated DC motors are often magnetized in their final assembled state. In that case, however, the magnetization of the permanent magnet rotor is usually negatively affected by the stator geometry. To achieve better magnetization of the permanent magnet rotor and consequently optimum efficiency of the DC motor, the permanent magnet rotor is preferably magnetized in a magnetizing device before assembly. The problem then is the considerable radial forces acting between the permanent magnet rotor and the stator during the joining process. Radial forces can cause impact and / or chipping of the permanent magnet rotor, particularly of the permanent magnets in the stator sheet packet. In that case, shavings are generated, which negatively affect bearing characteristics, bearing life, wear characteristics, and the like. Also, the coating of the permanent magnet may be damaged. These also reduce motor life and affect the functionality of the motor due to corrosion of the magnetic material.

  In order to guarantee the non-contact mounting of the DC motor in the stator, a complex joining device is required, which houses the DC motor and the stator equally and joins them in a defined manner. In that case, the pre-assembled rotor must be accommodated in the shaft part of the device. In many applications, this shaft portion forms or has a customer interface, which can be damaged when housed in a welding tool. In addition, the device is formed individually for each rotor type, thereby not being economical.

  It is therefore an object of the present invention to insert a pre-magnetized permanent magnet rotor into a cup-shaped motor housing without damaging the magnetic coating, causing abrasion and without damaging the customer interface in the shaft part. To find a simple economic potential.

  This object is achieved according to the invention by the features of claim 1 or by the method features of claim 7. The permanent magnet is connected to the shaft by a plastic hub. This is one possibility for fixing the permanent magnet. The plastic hub also has the additional function of a guide that projects radially beyond the permanent magnet. This guide allows the permanent magnet rotor to come into contact with the stator in the area of the guide without damaging the permanent magnet coating. This is because the coating maintains a small spacing with respect to the stator sheet packet. This solution is feasible in a simple and economical way and allows joining permanent magnet rotors without damaging the customer interface at the shaft end.

  The development of the invention is described in detail in the subclaims. The cup-shaped housing has, on the one hand, a closed cup bottom and, on the other hand, a mounting opening. The guide is located at the end of the permanent magnet rotor near the bottom of the cup. It is thereby ensured that the guide is first introduced into the rotor notch of the stator lamination packet, followed by the permanent magnet.

  Preferably, the radially extending guide has a radial extension of less than half the inner diameter of the stator slat packet. This design ensures that the permanent magnet rotor can be joined into the stator without forced wear.

  Preferably, the guide has a ring-like shape. In this way, the permanent magnet rotor can be magnetically pulled in any arbitrary radial direction without damaging the permanent magnet or its coating.

  Further, an introduction slope is provided, and the introduction slope is 15 ° to 30 °, preferably 20 ° with respect to the joining direction. The introduction ramp increases the alignment tolerance between the stator shaft and the rotor shaft during the joining process.

  According to a development of the invention, the plastic hub is non-rotatably form-locked with the permanent magnet and the shaft by a primary deformation process. For this purpose, the permanent magnet is provided with a recess into which the projection of the plastic hub fits. A knurl is provided on the shaft. Polyamide is provided as a plastic material.

  In order to avoid material accumulation, a notch is provided between the shaft and the permanent magnet, and the notch is interrupted by spokes.

  The stator lamella packet consists of laminated individual lamellas, which have a chamfered inner edge at the first lamella-side edge facing the mounting opening of the cup-shaped housing. The chamfered inner edge results from a punching process (shear), in which the sheet material is usually drawn into the sheet plane on one side and from this sheet plane on the opposite side. The orientation of the lamellas is usually selected such that stator lamella packets having chamfered outer edges are first joined into the cup housing. Usually, in this case, the inner edge is likewise and oriented chamfered or has a ridge. The present invention avoids an increase in the shaving action because the punching direction when drilling the rotor housing is not parallel to the punching direction when cutting the stator outer diameter.

  For reasons of tolerances and to further reduce the scraping action of the sheet packet in the cup housing, the stator is fixed via radially projecting tongues. To facilitate the mounting of the stator in the housing, no tongues are provided at the end portion. In the next part, only every other sheet, and in the next part in each case two successive sheets, are provided with tongues, which are separated by a sheet without tongues. I have. This stator formation is used as a compensating measure to compensate for the slightly conical inner contour of the deep drawn housing. Sheets without tongues allow simple displacement (bending), thereby reducing the shaving action. The part with a relatively loose arrangement of the individual sheets with a gap after each tongue is provided for the part with a relatively small inner diameter of the housing, the part with a denser and stiffer arrangement of the individual sheets. Are provided for areas having a larger inner diameter.

  In the event that shavings are generated, in particular by shaving the end sheets in the housing, these shavings are trapped by the receiving pockets in one or both winding insulations. Other shavings scraped by the tongues usually remain trapped in the gaps between the tongues.

Another solution is a stator with windings (2) having a stator lamination packet (3) and a cup-shaped housing (4) and a permanent magnet rotor (5) housed inside the lamination stator packet (3). The permanent magnet rotor comprises a shaft (6), a plastic hub (7) and a magnetized permanent magnet (8), wherein the permanent magnet (8) is rotated by a shaft (6) by a plastic hub (7). ), The method comprising forming an electronically commutated DC motor (1), the method comprising the following steps:
a) preparing a shaft (6) with knurls;
b) providing a permanent magnet (8) having an interlocking geometry;
c) Insert the shaft (6) and the permanent magnet (8) into the cavity of the injection molding tool,
d) injecting a thermoplastic plastic material into the remaining hollow chamber of the cavity while forming a guide (9) having an inlet slope (14);
e) removing the permanent magnet rotor (5) from the injection molding machine,
f) magnetizing the permanent magnet (8) in a magnetizing device;
g) Fit housing bearing (20) on shaft (6),
h) prepare the housing (4),
i) preparing a pre-assembled stator (2),
j) Press-fit the stator (2) into the housing (4) with the chamfered side of the individual lamination (12),
k) joining the magnetized permanent magnet rotor (5) first by means of the guide (9) into the stator notch and joining the housing bearing (20) into the housing (4);
That is the feature.

  For complete assembly, other intermediate or final assembly steps are required, which are not the subject of the present invention.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

It is sectional drawing which shows a stator and a permanent magnet rotor. It is an exploded perspective view showing a permanent magnet rotor. It is a fragmentary sectional view of a stator. It is sectional drawing of a permanent magnet rotor. It is a front view of a permanent magnet rotor.

  Note: Reference signs with subscripts (a, b) and reference signs without subscripts indicate things with the same name in the drawings and the drawing description. In that case it is another embodiment, use in the prior art, and / or details are variations. The claims, the specification introduction, the reference list and the abstract have, for simplicity, only reference numerals without subscripts.

FIG. 1 is a sectional view of an assembly including the stator 2, the permanent magnet rotor 5, and the bearing shield 36. The stator 2 has a stator laminar packet 3 comprising a cup-shaped housing 4, a housing bearing 20 and individual laminations 12, the individual laminations having chamfered edges 13 and ridges 28. The chamfered edges are formed in a stamping process. The punching direction when punching the rotor housing 43 is opposite to the punching direction when punching the outer periphery 44 of the individual thin plate 12. Thereby, both the stator thin plate packet 3 and the rotor 5 can be optimally mounted. The tongue 26 protrudes radially on the outer periphery 44. In order to be able to more clearly recognize the chamfered edges 13 and ridges 28 and their orientation, the stator 2 is shown simply (without windings, winding insulation and contacts), The individual sheets are exaggerated. The orientation of the stator lamella packets is selected such that the joining direction of the permanent magnet rotors 5 to be joined faces the chamfered side of the individual lamella 12. The end plates 49 at both ends of the stator plate packet do not have tongues and form a gap as small as possible with the housing 4. The housing 4 has a cylindrical area 29 and a cup bottom 10, the cup bottom being axially extended by a bearing housing 30. The permanent magnet rotor 5 has a shaft 6 with a flat 23 used as a customer interface, a plastic hub 7, a permanent magnet 8 and a guide 9 with a guide ramp 14 (see FIG. 3), in which case The guide 9 is located at the first end 11 of the permanent magnet rotor 5 facing the cup bottom 10. Since the diameter of the guide 9 is larger than the diameter of the permanent magnet 8, it is not possible for the permanent magnet 8 to contact the stator sheet packet 3. The housing bearing 20 is fixed by force coupling on a shaft end 31 facing the cup bottom 10. A ball bearing is used as the housing bearing 20, and its outer ring is
As soon as the stator 2 is mounted, it is slid into the cup housing 4, in particular the bearing housing 30. The spring disc 41 allows the ball bearing to be mounted without play. The bearing shield 36 has a seal in the shape of an O-ring 37, and the seal is inserted into the groove 38. The O-ring abuts the housing flange 42 in the assembled state. Further, a bearing shield bearing 39 is accommodated in the bearing shield 36, and is fixed by a beryllium clip disk 40.

  FIG. 2 shows an exploded perspective view of a permanent magnet rotor 5 having a shaft 6, a plastic hub 7 and a permanent magnet 8. The shaft 6 has a flat portion 23 as a customer interface, a guiding shaft end 31 and a knurl 15, and the knurl allows the plastic hub to be relatively non-rotatable and axially fixed on the shaft 6 so that it can be primarily molded. is there. The plastic hub 7 has a magnet receiving area 32, a guide 9, a retaining ring 21, a protrusion 19, a notch 16, a spoke 24, a cutout 17 and a shaft cutout 22. The magnet housing area 32 is defined in the axial direction by the holding ring 21 and the guide 9. The cutouts 16 are arranged between the shaft cutouts 22 and the magnet receiving area 32 and are separated from each other by spokes 24. The notches are used primarily to avoid material deposition. The permanent magnet 8 is here formed as a plastic-coupled permanent magnet ring, which is provided with a recess 18 corresponding to the protrusion of the plastic hub 7. The outer contour of the magnet housing 32 and the inner contour of the permanent magnet 8 are formed as polygons, thereby providing additional anti-rotation.

  FIG. 3 shows a partial cross-section of a stator 2 (without housing) having a stator lamination packet 3 and individual laminations 12, the individual laminations having tongues 26 which partially extend radially. Usually, the individual lamellas 12 with tongues 26 are followed by individual lamellas without tongues. In one area, two sheets, each with a tongue, are continuous with one another and are separated from other sheets with tongues by a sheet without the tongue. The end thin plate 49 in the start end region 33 and the end region 34 has no tongue. In these areas, the sheet diameter is smaller than the inner diameter of the housing, so that a simple joining into the mounting opening 25 (see FIG. 1) is possible. Nevertheless, the gap between the terminal lamella 49 and the housing 4 is chosen as small as possible in order to avoid at least larger shavings inside the lamella packet. Furthermore, insulations 27a, 27b are shown, which are used to house the stator windings and to electrically insulate them from the stator laminar packet 3. The insulating portion 27a has a storage pocket 35 for storing and holding shavings generated when the stator thin plate packet 3 is mounted in the housing. The arrow indicates the joining direction of the stator thin plate packet 3 when joining into the housing. The first insulating part 27a first enters into the housing, followed by the start end area 33 of the stator sheet packet 3, the loosely stacked first area 45, the densely stacked second area 46, and the end. The region 34 and finally the second insulating portion 27b enters. In the loosely stacked area 45, the individual sheets 12a with tongues 26 and the individual sheets 12b without tongues alternate with one another. In the densely stacked second region 46, two adjacent individual laminations 12a with tongues 26 and individual laminations 12b without tongues respectively alternate with one another. The reason for this is the slight conical shape of the housing and the possibility of shaving off the preceding first area 45 with individual sheets. The tongue 26 in the first area 45 must be more severely deformed than the tongue 26 in the second area 46 due to the reduced housing diameter. The first insulation has a sealing edge 47, which abuts the housing.

  FIG. 4 shows the shaft 6, the flat portion 23, the guiding shaft end 31, the knurl 15, the plastic hub 7, the notch 16, the spoke 24, the retaining ring 21, the guide 9 of the first end of the permanent magnet rotor 5 and The front view of the permanent magnet rotor 5 having a cutout 17 for accommodating the permanent magnet 8 in a defined manner in the injection molding tool. Detail A shows the guide 9 having the guide slope (14) in an enlarged manner, and the guide slope is inclined at an angle α and 20 ° with respect to the joining direction (the direction parallel to the axis).

  FIG. 5 shows the front (side) of the permanent magnet rotor 5 with the guiding shaft end 31, the plastic hub 7, the notch 16, the spoke 24, the guide 9, the guide ramp 14 and the cutout 17. In the example shown, three cutouts 16 and six cutouts 17 are provided.

DESCRIPTION OF SYMBOLS 1 DC motor 2 Stator 3 Stator thin plate packet 4 Housing 5 Permanent magnet rotor 6 Shaft 7 Plastic hub 8 Permanent magnet 9 Guide 10 Cup bottom 11 1st end 12 Individual thin plate 13 Beveled edge 14 Introducing slope 15 Knurling 16 Notch REFERENCE SIGNS LIST 17 cutout 18 retraction 19 projecting part 20 housing bearing 21 retaining ring 22 shaft cutout 23 flat part 24 spoke 25 mounting opening 26 tongue piece 27 insulating part 28 ridgeline 29 cylindrical area 30 bearing receiving part 31 guiding shaft end 32 Magnet accommodating area 33 Start end area 34 End area 35 Housing pocket 36 Bearing shield 37 O-ring 38 Groove 39 Bearing shield bearing 40 Beryllium clip disk 41 Spring disk 42 Housing flange 43 Rotor housing 44 Outer circumference 4 5 First area 46 Second area 47 Seal edge 48 Outer edge 49 Terminating thin plate

Claims (13)

An electronic device comprising a stator with windings (2) having a stator sheet packet (3) and a cup-shaped housing (4), and a permanent magnet rotor (5) housed inside the stator sheet packet (3). DC motor (1), wherein the permanent magnet rotor has a shaft (6), a plastic hub (7) and a magnetized permanent magnet (8), the permanent magnet (8) being a plastic hub. The plastic hub (7) has a guide (9) radially projecting beyond the permanent magnet (8), which is connected to the shaft (6) by (7), and the stator sheet packet (3) is laminated An inner edge (13) chamfered on the individual thin plate (12), comprising a central notch used as a rotor receiving part (43), comprising: Inside d The end faces the mounting opening (25) of the cup-shaped housing (4) and faces away from the cup bottom (10) of the housing (4), and in the first part after the end lamination, the tongue The individual lamella (12) with the strip (26) and the individual lamella without the tongue are continuous with one another, and in the second part at least two mutually adjacent individual lamellas with the tongue are formed by the tongue. An electronically commutated DC motor that takes the place of individual laminations without .   A cup-shaped housing (4) has, on the one hand, a closed cup bottom (10) and, on the other hand, a mounting opening (25), the guide (9) being the cup of the permanent magnet rotor (5). 2. The electronically commutated DC motor according to claim 1, wherein the DC motor is arranged at an end (11) close to the bottom (10).   Electronically according to claim 1 or 2, characterized in that the radially extending guide (9) has a radial extension smaller than half the inner diameter of the stator lamination packet (3). DC motor to be rectified.   Electronically commutated DC motor according to claim 1, 2 or 3, wherein the guide (9) has a ring-like shape. Electronically commutated DC motor according to claim 1, 2, 3 or 4, wherein the guide (9) has an inlet bevel (14) towards the cup bottom (10). 5. The plastic molding device according to claim 1, wherein the plastic hub is connected to the permanent magnet and the shaft in a non-rotatably complementary manner by a primary molding process. 6. The electronically commutated DC motor of claim 5. The same individual lamella (12) is provided on its outer periphery with a chamfered outer edge (48) facing away from the mounting opening (25) of the cup-shaped housing (4) and towards the cup bottom (10). An electronically commutated DC motor according to claim 1 , comprising: The stator lamination packet (3) consists of various laminations, and a number of individual laminations (12) have tongues (26) projecting into one angular region, by means of which the stator lamination packet (3) is formed. ) is an electronically commutated according to claim 7, wherein in that, it has a cutout in the housing (4) are clamped in, and a number of other individual thin same angular region DC motor. 9. The electronically commutated DC motor according to claim 8 , wherein the plurality of individual lamellas have neither tongues nor cutouts. 10. The electronically commutated DC motor according to claim 9 , wherein a gap as small as possible remains between the housing (4) and the end strip (49). 11. At least one of the claims 1 to 10 , wherein an insulating part (27) is continuous with the stator sheet packet (3), said insulating part having a storage pocket (35) for shavings. Electronically commutated DC motor as described. Electronically commutated DC motor according to claim 11 , characterized in that the sealing edge (47) of the storage pocket (35) abuts the housing (4). A stator (2) having windings, comprising a stator lamination packet (3) and a cup-shaped housing (4); and a permanent magnet rotor (5) housed inside the stator lamination packet (3), A permanent magnet rotor has a shaft (6), a plastic hub (7) and a magnetized permanent magnet (8), the permanent magnet (8) being coupled to the shaft (6) by a plastic hub (7), and a stator laminar packet. (3) consists of laminated individual sheets (12) and has a central notch used as a rotor receiving part (43), provided with an inner edge (13) chamfered on the individual sheets (12). The inner edge faces the mounting opening (25) of the cup-shaped housing (4) and faces away from the cup bottom (10) of the housing (4), and 1 In the part, the individual laminations (12) with tongues (26) and the individual laminations without tongues are continuous with one another, and in the second part at least two consecutive individual laminations with tongues (12) In the method of forming an electronically commutated DC motor (1) , which alternates with individual lamellae without tongues , the following method steps:
a) preparing a shaft (6) with knurls;
b) providing a permanent magnet (8) having an interlocking geometry;
c) Insert the shaft (6) and the permanent magnet (8) into the cavity of the injection molding tool,
d) injecting a thermoplastic plastic material into the remaining hollow chamber of the cavity while forming a guide (9) having an inlet slope (14);
e) removing the permanent magnet rotor (5) from the injection molding machine,
f) magnetizing the permanent magnet (8) in a magnetizing device;
g) Pull the housing bearing onto the shaft (6),
h) prepare the housing (4),
i) preparing a pre-assembled stator (2),
j) Press-fit the stator (2) into the housing (4),
k) previously joining the magnetized permanent magnet rotor (5) by means of a guide (9) into the rotor housing (43) and joining the housing bearing (20) into the housing (4);
A method of forming an electronically commutated DC motor.

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