WO2017008796A1 - Magnet wheel for an electric motor - Google Patents

Abstract

The invention relates to an electric motor (1) comprising a stator (19) and a rotor (18), which is rotatably mounted in a housing, and comprising a magnet wheel (2) which is mounted for conjoint rotation on the rotor (18). For an electric motor (1) comprising a magnet wheel (2), the object of the invention is to ensure that same is easy to produce and assemble, whereby a reduced axial construction length is required, and an accurate axial assignment and positioning in relation to a sensor secured to a stator is possible. This problem is solved according to the invention by the features of device claim 1 and the features of method claim 22.

Description

 Title: MAGNETIC GEBERPOLRAD FOR AN ELECTRIC MOTOR

description

The invention relates to an electric motor (1) with a stator (19) and a rotor (18) which is rotatably mounted in a housing, with a Geberpolrad (2) which is rotatably mounted on the rotor (18).

In DE 198 23 640 a mounted on a shaft Geberpolrad is described in which, despite different thermal expansion coefficients of

metallic shaft and a plastic-bonded permanent magnet to be made a press connection. The problem is solved in that the encoder wheel consists of two axial sections, with a first section is freed to the shaft and a second section by means of a ring-like

Auxiliary body is pressed as a reinforcing element. Because of the two

Axial sections an enlarged axial space is required. In addition, the Geberpolrad despite the great length is attached to one side only on a short section. The arrangement further requires an additional joining process for the assembly of the Verstärkungsmitteis.

The object of the invention is therefore to ensure in an electric motor with Geberpolrad that this is easy to manufacture and assemble, it requires a small axial length and accurate axial assignment and attitude adjustment to a statorfesten sensor is possible.

This object is achieved by the features of

Device claim 1 and solved by the features of method claim 22. It is proposed that the encoder pole wheel (2) consists of a magnetic ring (7), which is designed for the magnetic properties and from a support (3), which may consist of a simple plastic material, to which no particularly high demands on strength and Heat resistance are provided. Since the carrier (3) has fastening means (4) which extend axially extend in recesses (12) of the rotor (18) and engage in this, an excellent positive rotational drive is given.

Further developments of the invention are presented in the subclaims. It has proven to be advantageous if the carrier (3) comprises a support or a plurality of supports (6) which are supported on a shaft (25) of the rotor (18). This support prevents the Geberpolrad (2) has a tendency to tilt or tilted mountable.

In order to be able to ensure this effect permanently, it is provided that the support or the supports (6) has a shape adapted to a cylindrical surface

Bearing surface / bearing surfaces (34) has / which directly on the shaft (25) abuts / abut. Since the shaft (25) also has a cylindrical surface is given a large area, rich contact surface or contact surfaces (34), which undergo no change in shape even under vibration stress and lose the advantage described.

Preferably, three or more supports (6) are provided, to which radially a sleeve (29) adjoins or that in a support (6) this is sleeve-shaped. This results in a precise centering of the encoder pole wheel (2) on the shaft (25).

On the one hand to achieve a simple assembly without risk of damage to the encoder rotor (2) and on the other hand a possible backlash-free connection between encoder rotor (2) and shaft (25) is provided that the support or the supports (6) with the shaft (25) a transition fit is dimensioned / are.

According to a particularly advantageous embodiment of the invention, the

Transmitter (2) one or more axial stops (36), the axially projecting from this or projecting. The or the axial stop / axial stops (36) closes / close to the support or the supports (6) axially. As a result, during assembly, the final position of the Geberpolrads (2) by axial

Pressurization defined to be set. Radially on the sleeve (29) or on the sleeve-shaped support (6) is followed by an annular disc-shaped hub (30). The hub (30) serves to bridge a radial distance between the shaft (25) or the supports (6) and / or the sleeve (29) and the magnetic ring (7), wherein as possible no material accumulations should occur, the Deformations would lead after cooling of the injection molding compound. Therefore, the hub (30) is disc-shaped, so that the entire carrier (3) has approximately the same wall thickness in its different areas.

Conveniently, a magnetic receiving ring (9) connects radially to the hub (30). It is further provided that the magnet receiving ring (9) at its axial ends in each case by an annular wall (37) is axially expanded, wherein between the magnet receiving ring (9) and the annular walls (37) has a groove (33) is formed. This groove (33) serves as axial securing for the magnetic ring (7). Due to the

Annularity of the magnet ring (7) this is also held radially secure.

Depending on the design, at least part of the magnet ring (7) may be received in the groove (33) or the magnet ring (7) may extend radially beyond the groove (33). Furthermore, the magnetic ring (7) can extend axially outside the groove (33) so far that the axial boundary of the ring walls (37) and the magnet ring (7) lie in one plane. This results in a wider magnetic ring (7), which is more likely the encoder rotor (2) directly opposite. To amplify this effect could be the magnetic ring (7), depending on whether this is the

Ambient geometry allowed, even further over the ring walls (37)

survive.

The fastening means (4) are at least partially axially connected to the hub (30). But you can also at least partially axially to the

Connect the magnet retaining ring (9), depending on how the diameters of the

Fastening means (4) and the corresponding recesses (12) of the rotor (18) are dimensioned.

Particularly advantageous is the further embodiment of the fastening means (4) to the effect that they are to a remote from the encoder rotor (2)

Rejuvenate areas. On the one hand, this facilitates the joining process in the Recesses (12) and on the other hand, the press-in force increases depending on the Einpresstiefe. However, since the taper is relatively small, the axial position of the encoder pole wheel (2) can be adjusted without problems over a larger axial range.

This effect is further improved by the fastening means (4) along their axial extension recesses (14), which z. B. in the form of notches (40), slots (32) and / or cavities (31) may be formed, because in this way a certain flexibility is achieved.

A frictional connection is the better, the rougher a joining surface.

Therefore, it makes sense that the fastening means (4) in recesses (12) of a rotor core (26) axially positive fit in the direction of rotation form fit

are included.

To ensure that the Geberpolrad (2) remains in its axial position, is provided between the rotor core (26) and the Geberpolrad (2) to arrange a spring (42), which the Geberpolrad (2) axially to the second

Deep groove ball bearing (15) presses. Thus thereby the number of parts and the

Mounting effort is increased, it makes sense that the spring (42) consists of the material of the carrier (3) and is integral therewith.

A second solution of the problem is by a method with the following

Achieved method steps: a) providing a rotor assembly, consisting of a shaft (25), a pressed rotor laminated core (26) with mounted

Permanent magnets (27); b) pre-assembly of a Geberpolrads (2) in recesses (12) of the rotor core (26); c) pressing a deep groove ball bearing (15) on the shaft (25) and setting a defined distance measure between a

Shaft end and an inner ring (39) of the deep groove ball bearing (15), wherein the

Encoder pole (2) further into the recesses (12) of the rotor core (26) are pressed. By means of these measures, manufacturing tolerances of the individual parts of the electric motor (1), which have an influence on the position of a magnetic sensor, can be compensated in an elegant manner. For further assembly, the permanent magnets (27) and a magnetic ring (7) of the encoder pole wheel (2) are magnetized simultaneously. As a result, an additional process step is saved.

Finally, a stator assembly consisting of a housing pot (10) with a mounted stator (19) and mounted first deep groove ball bearing (8) serving as a fixed bearing is provided and the stator assembly is mounted on the rotor assembly with a sleeve-like tool attached to an inner ring (39 ) of the first deep groove ball bearing (8) brought into abutment and this defined on the shaft (25) is pressed.

An embodiment of the invention will be explained in more detail with reference to an example. Show it:

1 is an end view of a first embodiment of a Geberpolrads,

2 is a perspective view of the Geberpolrads shown in FIG. 1,

3 shows a representation according to FIG. 2 from a different perspective,

4 is a sectional view of the first embodiment of the Geberpolrads,

5 shows a further sectional view of the encoder pole wheel,

6 is another end view of the encoder pole,

7 is a rotor-mounted Geberpolrad,

8 shows a second embodiment of a Geberpolrads,

Fig. 9 shows a variant of the second embodiment of the Geberpolrads and

10 shows an electric motor with a Geberpolrad the first embodiment. Note: Reference numerals with apostrophe and corresponding reference numerals without apostrophe designate same-named details in the drawings and the description of the drawings. It is the use in another embodiment, the prior art and / or the detail is a variant. The claims, the introduction to the description, the list of reference numerals and the abstract contain, for the sake of simplicity, only reference symbols without an apostrophe.

FIGS. 1 to 6 show a first one from different perspectives

Embodiment of a Geberpolrads 2, consisting of a support 3 and a magnetic ring 7. The carrier 3 consists of an annular disc-shaped hub 30, to which six fastening means 4, a central sleeve 29 and a

Connect magnet receiving ring 9. The magnet receiving ring 9 (see Fig. 2) continues radially through two annular walls 37, which are spaced from each other. The magnet receiving ring 9 and the annular walls 37 together form a radially outwardly open groove 33 (see FIG. 2). The groove 33 is filled by a magnetic ring 7. The magnetic ring 7 continues radially over the annular walls 37 and forms a cylindrical outer contour. The axial boundary of the magnet ring 7 and the axial boundary of the annular walls 37 lie in one plane. The sleeve 29 projects axially relative to the magnetic ring 7 and the ring walls 37. Close to the sleeve 29 radially inward three by 120 ° angular distance from each other

Support 6, which serve as a support means. These have radially inner bearing surfaces 34 which are adapted to a cylinder jacket surface. In a mounted

Condition they form a transition fit with a shaft 25 (see Fig. 9). Axially, the supports 6 each have an axial stop 36 (see FIG. 2); these serve to rest on a second deep groove ball bearing 15 (see FIG. 9). The axial stops 36 project axially relative to the sleeve 29. The fastening means 4 have the form of tapered, slotted sleeves 29, with cavities 31 and one inwardly directed slot 32. The fastening means 4 serve as

Anti-rotation device for the Geberpolrad 2. A chamfer 35 (see Fig. 3, 4) at the end of the fastening means 4 and also the taper to the introduction into

Recesses 12 of a rotor core 26 facilitate (see Fig. 9). The

Rejuvenation is also intended for a firm, non-positive connection in these

Recesses 12 provide. The slots 32 allow a certain Resiliency of the fastening means 4, so that their diameter can be slightly reduced and adapted to the recesses 12 in the laminated core. The fastening means 4 extend radially from the sleeve 29 via the hub 30 to the magnet receiving ring 9. The carrier 3 is integral with the sleeve 29, the hub 30, the fastening means 4, the supports 6 and the magnet receiving ring 9. The magnetic ring 7 consists of a plastic-bonded permanent magnet 27 (see Fig. 1), z. A rare earth magnet such as NdFeB. The Geberpolrad 2 is produced by means of a two-component injection molding process, wherein first the carrier 3 is urgeformt of a plastically deformable plastic material in a first cavity and then the magnetic ring 7 from the

plastic-bonded permanent magnet material is joined in a second cavity with the carrier 3 by prototyping. On the material of the carrier 3 no very high demands are made, because due to the positive connection with the rotor core 26 can be dispensed with a press connection with the shaft 25. The supports 9 prevent tilting of the Geberpolrads 2 may occur. In Fig. 1, a cone-like Entformungsschräge 41 is indicated, which facilitates demolding of an injection molding tool. The supports 6 have no Entformungsschrägen 41 in order to provide a defined bearing surface.

Fig. 7. Shows in two by 150 ° to each other inclined cutting planes (see line AA in Fig. 1) the Geberpolrad 2 of the first embodiment mounted on a rotor 18, wherein the integral with the carrier 3 fastening means 4 in axially parallel recesses 12 of a rotor core 26 extend and are held therein non-positively. A support 6 of the encoder pole wheel 2, which is integral with the carrier 3, rests on a shaft 25. This prevents tilting of the encoder pole wheel 2. An axial stop 36 lies axially against the inner ring 39 of a

Deep groove ball bearings 15 on. This makes it possible that when joining the

Deep groove ball bearings 15, the press-in depth of the fastener 4 in the

Recesses 12 is set. Basically, the number of

Fastener 4 freely selectable, but it is recommended to provide at least two, preferably three or more fasteners 4.

Fig. 8 shows stylized a second embodiment of a Geberpolrads 2 ', with a carrier 3' and a magnetic ring 7 '. With the carrier 3 'here are two Fastener 4 'in one piece, which extend axially parallel to the carrier 3' away. The fastening means 4 'are each provided with four tapered ribs 38, which form a cross-shaped arrangement and are separated from one another by notches 40. Bearing 6 are omitted here for the sake of simplicity, but they can be shaped similar to the first embodiment. Instead of discrete supports, an annular support 6 'could also be used.

Fig. 9 shows a variant of the second embodiment of the encoder rotor 2 ", in which a spring 42 made of plastic with the carrier 3" is in one piece. The spring 42 consists of two spaced-apart and interconnected by webs 17 rings 13. Further webs 17 connect the first of the rings 13 with the carrier 3 "The arranged between the rings 13 webs 17 are compared with the between the support 3" and the Sensor 43 (see Fig. 1 0) arranged webs 17 angularly offset by 90 °. On the outer ring 13 close axially two projections 23, which are angularly offset by 90 ° relative to the rings 13 connecting webs 17. The projections 23 serve as defined contact surfaces for installation on

Rotor sheet package 26. Due to the angular offset of the webs 17 with each other and the projections 23 with respect to the webs 17 a compliance of the spring 42 is made possible by the areas of the rings 13 between the webs 17 in

Axial direction are resiliently deflectable. By the spring 42 is always

ensures that the encoder rotor 2 "rests on the second deep groove ball bearing 15.

10 shows an assembly drawing of an electric motor 1, which is an electronically commutated DC motor, which comprises a rotor 18 equipped with permanent magnets 27, a stator 19 wound with a winding 24, and a housing. The housing consists of a bearing plate 20 and the housing pot 10. The rotor 18 consists of a smooth shaft 25, a rotor core 26, the permanent magnet 27 and a

Geberpolrad 2, which on a support 3 (see Fig. 1 to 6) is held, which is pressed axially via fastening means 4 in recesses 12 of the rotor core 26 lamination. With the Geberpolrad 2 a sensor 43 cooperates, which is arranged on a circuit board 21 radially to the Geberpolrad 2; Alternatively, an axial arrangement would be possible. The printed circuit board 21 is formed as an overmolded guide plate, which comprises a plug 22. Next is a first deep groove ball bearing 8, which is fixed to the spring steel disc 5, a second deep groove ball bearing 15, a cap 1 6, which is fixed in a recess 14, a flanged gear pump 28 and a laminated stator core 1 1 shown. When mounting the encoder pole wheel 2, the axial position relative to the rotor 18 can be adjusted within certain limits to the respective actual dimensions. Serve for this purpose, the axial stops 36 (see FIGS. 1 to 6), which can be supported on the inner ring 39 of the second deep groove ball bearing 15. In this way, a precise position assignment to the sensor 43 can be produced. The encoder pole wheel 2 and the rotor 18 each have three north poles and three south poles.

LIST OF REFERENCE NUMBERS

Electric motor 30 hub

 Encoder pole wheel 31 cavity

 Carrier 32 slot

 Fastener 33 groove

 Spring steel disc 34 bearing surface

Support 35 chamfer

 Magnetic ring 36 Axial stop first deep groove ball bearing 37 Ring wall

 Magnetic receiving ring 38 rib

 Housing pot 39 inner ring

 Stator laminated core 40 notch

 Recesses 41 Draft bevel

Ring 42 spring

 Clearance 43 sensor

second deep groove ball bearing

 cap

 web

 rotor

 stator

 end shield

 circuit board

 plug

 head Start

 winding

 wave

 Laminated core

 permanent magnet

 gear pump

 shell

Claims

claims 1 . Electric motor (1) with a stator (19) and a rotor (18) which is rotatably mounted in a housing, with a Geberpolrad (2) which is rotatably mounted on the rotor (18), characterized in that the  Encoder pole (2) consists of a carrier material consisting of plastic material (3) and a magnetic ring (7) and the carrier (3) fastening means (4) which engage axially in recesses (12) of the rotor (18). 2. Electric motor (1) according to claim 1, characterized in that the carrier (3) comprises a support or a plurality of supports (6) which are supported on a shaft (25) of the rotor (18). 3. Electric motor (1) according to claim 2, characterized in that the  Support or the supports (6) has / adapted to a cylinder surface surface bearing surface / bearing surfaces (34) / have, which bear directly on the shaft (25). 4. Electric motor (1) according to claim 2 or 3, characterized in that the support or the supports (6) with the shaft (25) according to a  Transitional fit is dimensioned / are. 5. Electric motor (1) according to one of claims 2 to 4, characterized  in that three or more supports (6) are provided, to which a sleeve (29) radially adjoins or that in the case of a support (6), this is sleeve-shaped. 6. Electric motor (1) according to claim 1, 2, 3, 4 or 5, characterized in that the Geberpolrad (2) has one or more axial stops (36), which projects axially from this or projecting. 7. Electric motor (1) according to claim 6, characterized in that the or the axial stop / axial stops (36) to the support or the supports (6) axially connects / connect. 8. Electric motor (1) according to at least one of claims 2 to 7, characterized in that the Geberpolrad (2) via the axial stops (36) on a bearing, in particular the inner ring (39) of a deep groove ball bearing (15) are axially supportable. 9. Electric motor (1) according to claim 5, 6, 7 or 8, characterized in that radially adjoins the sleeve (29) or the sleeve-shaped support (6) an annular disc-shaped hub (30). 10. Electric motor (1) according to claim 9, characterized in that radially adjoins the hub (30) has a magnetic receiving ring (9). 1 1. Electric motor (1) according to claim 10, characterized in that the  Magnetic receiving ring (9) at its axial ends in each case by a  Ring wall (37) is axially expanded, wherein between the magnet receiving ring (9) and the annular walls (37) has a groove (33) is formed. 12. Electric motor (1) according to claim 1 1, characterized in that  at least part of the magnet ring (7) is received in the groove (33). 13. Electric motor (1) according to claim 12, characterized in that the  Magnetic ring (7) extends radially over the groove (33). 14. Electric motor (1) according to claim 13, characterized in that the  Magnetic ring (7) extends axially outside the groove (33) so far that the axial boundary of the ring walls (37) and the magnet ring (7) lie in one plane. 15. Electric motor (1) according to at least one of claims 9 to 14, characterized  characterized in that the fastening means (4) at least partially axially to the hub (30). 16. Electric motor (1) according to at least one of claims 9 to 15, characterized characterized in that the fastening means (4) at least partially axially to the magnetic receiving ring (9). 17. Electric motor (1) according to at least one of the preceding claims, characterized in that the fastening means (4) taper towards one of the encoder rotor (2) remote areas. 18. Electric motor (1) according to at least one of the preceding claims,  characterized in that the fastening means (4) along their axial extension recesses (14) which z. B. in the form of notches (40), slots (32) and / or cavities (31) may be formed. 19. Electric motor (1) according to at least one of the preceding claims,  characterized in that the fastening means (4) in recesses (12) of a rotor laminated core (26) are positively received in a non-positively locking and rotational direction. 20. Electric motor (1) according to at least one of the preceding claims,  characterized in that between the rotor laminated core (26) and the Geberpolrad (2) a spring (42) is arranged, which presses the Geberpolrad (2) axially to the second deep groove ball bearing (15). 21. Electric motor (1) according to claim 20, characterized in that the  Spring (42) consists of the material of the carrier (3) and is integral therewith. 22. A method for mounting a Geberpolrads (2) on a rotor (18) of an electric motor (1) comprising a housing and a stator (19), characterized by the following method steps: a) providing a rotor assembly consisting of a shaft (25 ), a pressed rotor laminated core (26) with mounted permanent magnets (27); b)  Pre - installation of an encoder rotor (2) in recesses (12) of the Rotor laminated core (26); c) pressing a deep groove ball bearing (15) onto the shaft (25) and setting a defined distance between a shaft end and an inner ring (39) of the deep groove ball bearing (15), wherein the encoder rotor (2) further into the recesses (12) of the rotor core ( 26) is pressed. 23. A method for mounting a encoder rotor (2) according to claim 22,  characterized by the further method step: d) magnetizing the rotor (18), wherein the permanent magnets (27) and a magnetic ring (7) of the encoder pole wheel (2) are magnetized simultaneously. 24. A method for mounting a Geberpolrads (2) according to claim 22 or 23, characterized by the further process step: e) providing a stator assembly consisting of housing pot (10) with mounted stator (19) and mounted first deep groove ball bearing (8), which as Fixed camp serves; f) Pressing the stator assembly on the rotor assembly, wherein a tool by an inner ring (39) of the first deep groove ball bearing (8) defined on the shaft (25) is pressed.