ELECTRIC MOTOR FOR DRIVING A VEHICLE FLAP, USE AND METHOD OF MANUFACTURING OF THE ELECTRIC MOTOR

Abstract

An electric motor for driving a vehicle flap is provided, the electric motor including a hollow-cylindrical shaped stator made of a permanent-magnetic material and arranged coaxially to a motor axis, a motor shaft disposed coaxially with the motor axis and at least partially within the stator and mounted for rotation relative to the stator about the motor axis, and a drive rotor disposed within the stator and mounted on the motor shaft and including a plurality of coils for driving rotation of the motor shaft relative to the stator about the motor axis. The electric motor includes a braking rotor disposed in the stator, mounted on the motor shaft along the motor axis adjacent the drive rotor, the brake rotor being magnetisable by the stator. Use of the electric motor for driving a vehicle flap and to a method of manufacturing the electric motor is also provided.

Claims

1. An electric motor for driving a vehicle flap, the electric motor comprising: a. a hollow-cylindrical shaped stator having a permanent magnetic material and arranged coaxially to a motor axis; b. a motor shaft arranged coaxially to the motor axis and at least partially in the stator and mounted rotatably relative to the stator about the motor axis and c. a drive rotor disposed in the stator and mounted on the motor shaft, including a plurality of coils for driving rotation of the motor shaft relative to the stator about the motor axis; and d. wherein a brake rotor arranged in the stator and fixed along the motor axis next to the drive rotor on the motor shaft, the brake rotor being magnetisable by the stator.

2. The electric motor according to claim 1, wherein an outer radius of the brake rotor radially to the motor axis corresponds to an outer radius of the drive rotor radially to the motor axis.

3. The electric motor according to claim 1, wherein the brake rotor is spaced from the motor shaft radially to the motor axis by a spacer sleeve.

4. The electric motor according to claim 3, wherein the spacer sleeve is plastic.

5. The electric motor according to claim 3, wherein the spacer sleeve contains at least one recess for reducing thermal expansion of the spacer sleeve.

6. The electric motor according to claim 3, wherein the spacer sleeve is positively connected to the motor shaft and/or to the brake rotor with respect to a rotation about the motor axis and/or with respect to a translation along the motor axis.

7. The electric motor according to claim 1, wherein a distance along the motor axis between the brake rotor and the drive rotor for thermal and/or magnetic decoupling of the brake rotor from the drive rotor.

8. The electric motor according to claim 1, wherein a shielding element for thermal and/or magnetic shielding of the brake rotor from the drive rotor is arranged along the motor axis between the brake rotor and the drive rotor.

9. The electric motor according to claim 1, wherein a housing enclosing the stator, the drive rotor and the brake rotor, the stator being fixed to the housing, and the motor shaft being mounted on the housing rotatably about the motor axis.

10. The electric motor according to claim 9, wherein the stator is positively connected to the housing with respect to a rotation about the motor axis and/or a translation along the motor axis, wherein an adapter insert is arranged along the motor axis between the stator and the housing.

11. The electric motor according to claim 1, wherein the permanent magnetic material of the stator is a ferrite.

12. Use of the electric motor according to claim 1 for driving a vehicle flap.

13. A method of manufacturing the electric motor according to claim 1, wherein: a. fixing the drive rotor and the brake rotor on the motor shaft; and b. placing the motor shaft in the stator.

14. The method according to claim 13, wherein: injection moulding a spacer sleeve into the brake rotor prior to fixing the brake rotor to the motor shaft so that the spacer sleeve spaces the brake rotor radially to the motor axis from the motor shaft after fixing.

15. The method according to claim 13, wherein: balancing the motor shaft with respect to rotation about the motor axis by reworking the drive rotor after fixing the drive rotor and the brake rotor on the motor shaft and before placing the motor shaft in the stator.

Description

BRIEF DESCRIPTION

[0051] Some of the embodiments will be described in detail, with references to the following Figures, wherein like designations denote like members, wherein:

[0052] FIG. 1 shows a schematic longitudinal section of an electric motor according to embodiments of the invention;

[0053] FIG. 2 shows a schematic cross-section of the brake rotor of the electric motor from FIG. 1;

[0054] FIG. 3 shows an enlarged section of FIG. 1 in the area of the brake rotor;

[0055] FIG. 4 shows an enlarged section of FIG. 1 in the area of the brake rotor with an alternatively designed spacer sleeve;

[0056] FIG. 5 shows a schematic longitudinal section of another electric motor according to embodiments of the invention;

[0057] FIG. 6 shows a schematic view of the spacer sleeve of the electric motor from FIG. 1; and

[0058] FIG. 7 shows a schematic view of the motor shaft of the electric motor from FIG. 1.

DETAILED DESCRIPTION

[0059] FIG. 1 shows a schematic longitudinal section along the motor axis MA of an electric motor 100 according to embodiments of the invention.

[0060] The electric motor 100 shown comprises a stator 130 of hollow cylindrical shape and arranged coaxially with the motor axis MA and made of a permanent magnetic material, for example a ferrite.

[0061] The electric motor 100 shown includes a motor shaft 120 disposed coaxially with the motor axis MA and partially within the stator 130 and mounted for rotation relative to the stator 130 about the motor axis MA, and a drive rotor 140 disposed within the stator 130 and mounted on the motor shaft 120 and including a plurality of coils 141 for driving rotation of the motor shaft 120 relative to the stator 130 about the motor axis MA.

[0062] The electric motor 100 shown comprises a braking rotor 150, for example made of an aluminium-nickel-cobalt alloy, arranged in the stator 130, fixed along the motor axis MA at a distance of, for example, 3 mm to 5 mm next to the drive rotor 140 on the motor shaft 120 and magnetisable by the stator 130.

[0063] For example, an outer radius of the brake rotor 150 radial to the motor axis MA corresponds to an outer radius of the drive rotor 140 radial to the motor axis MA.

[0064] The brake rotor 150 is spaced from the motor shaft 120 radially to the motor axis MA by a spacer sleeve 160, for example made of a plastic material.

[0065] The brake rotor 150 and the spacer sleeve 160 are described in more detail with reference to FIGS. 2 to 4.

[0066] The electric motor 100 shown comprises a housing 110 enclosing the stator 130, the drive rotor 140 and the brake rotor 150, the stator 130 being fixed to the housing 110, and the motor shaft 120 being mounted on the housing 110 rotatably about the motor axis MA. For example, the motor shaft 120 is mounted to the housing 110 at each end of the housing 110 along the motor axis MA via a respective bearing 170.

[0067] FIG. 2 shows a schematic cross-section perpendicular to the motor axis MA through the brake rotor 150 of the electric motor 100 from FIG. 1.

[0068] FIG. 2 shows that the spacer sleeve 160 is positively connected to the motor shaft 120 and the brake rotor 150 with respect to rotation about the motor axis MA.

[0069] The spacer sleeve 160 shown has a number of projections 163, for example four projections 163 each offset by 90° about the motor axis MA, on an outer lateral cylinder surface of the spacer sleeve 160 (only two projections are visible in the sectional plane shown). The projections are rounded, for example. The brake rotor 150 comprises depressions 153 of complementary shape to the projections 163, in which the projections 163 engage positively with respect to rotation about the motor axis MA.

[0070] For positive connection of the spacer sleeve 160 to the motor shaft 120, an outer surface of the motor shaft 120 shown is flattened on one side, wherein an inner lateral cylindrical surface of the spacer sleeve 160 interacts positively with the flattening 121 of the motor shaft 120 with respect to a rotation about the motor axis MA.

[0071] The spacer sleeve 160 shown comprises an inner cylinder 165 abutting the motor shaft 120 and coaxial with the motor axis MA and an outer cylinder 166 abutting the brake rotor 150 and coaxial with the motor axis MA. The outer cylinder 166 is radially spaced from the inner cylinder 165 with respect to the motor axis MA and is connected to the inner cylinder 165 only by a number of, for example eight, curved webs 167. Recesses 168 are located between the webs 167.

[0072] FIG. 3 shows an enlarged section of FIG. 1 in the area of the brake rotor 150.

[0073] FIG. 3 shows that the spacer sleeve 160 is positively connected to the motor shaft 120 and to the brake rotor 150 with respect to a translation along the motor axis MA.

[0074] For positive connection of the spacer sleeve 160 to the brake rotor 150 with respect to a translation along the motor axis MA, the spacer sleeve 160 shown has a number of projections 163, for example four projections 163 each offset by 90° about the motor axis MA on an outer lateral cylinder surface of the spacer sleeve 160 (only two projections are visible in the sectional plane shown). The brake rotor 150 comprises depressions 153 of complementary shape to the projections 163, in which the projections 163 engage positively with respect to a translation along the motor axis MA.

[0075] For positive connection of the spacer sleeve 160 to the motor shaft 120 with respect to translation along the motor axis MA, the motor shaft 120 shown comprises a shoulder 122 arranged around the motor axis MA and a ring 123 fixed to the motor shaft 120, for example a steel ring pressed onto the motor shaft 120, the spacer sleeve 160 being arranged along the motor axis MA between the shoulder 122 and the ring 123.

[0076] FIG. 4 shows an enlarged section of FIG. 1 in the area of the brake rotor 150 with an alternatively designed spacer sleeve 160.

[0077] The spacer sleeve 160 shown in FIG. 4 differs from the spacer sleeve 160 shown in FIG. 3 in that it has a guide section 164 extended relative to the brake rotor 150 along the motor axis MA for guiding the motor shaft 120 in the spacer sleeve 160. The guide section 164 prevents tilting of the spacer sleeve 160 relative to the motor shaft 120 and thereby improves the smooth running and durability of the electric motor 100.

[0078] FIG. 5 shows a schematic longitudinal section along the motor axis MA of a further electric motor 100 according to embodiments of the invention.

[0079] The electric motor 100 shown in FIG. 5 differs from the electric motor 100 shown in FIG. 1 in that the stator 130 is positively connected to the housing 110 with respect to a translation along the motor axis MA, wherein an adapter insert 111, for example an adapter ring arranged around the motor axis MA, is arranged along the motor axis MA between the stator 130 and the housing 110.

[0080] FIG. 6 shows a schematic view of the spacer sleeve 160 of the electric motor 100 from FIG. 1.

[0081] The spacer sleeve 160 shown has a number of projections 163, for example four projections 163 each offset by 90°, on an outer cylindrical surface of the spacer sleeve 160 for positive connection of the spacer sleeve 160 to the brake rotor (not shown) of the electric motor 100 (only three projections are visible in the view shown). The projections are rounded, for example.

[0082] For positive connection of the spacer sleeve 160 to the motor shaft (not shown) of the electric motor 100, an inner cylindrical surface of the spacer sleeve has a flattening 169.

[0083] The spacer sleeve 160 shown comprises an inner cylinder 165 for contact with the motor shaft 120 of the electric motor 100 and an outer cylinder 166 for contact with the brake rotor 150. The outer cylinder 166 is spaced from the inner cylinder 165 and is connected to the inner cylinder 165 only by a number of, for example eight, curved webs 167. Recesses 168 are located between the webs 167.

[0084] FIG. 7 shows a schematic view of the motor shaft 120 of the electric motor 100 of FIG. 1.

[0085] For positive connection of the spacer sleeve (not shown) of the electric motor 100 to the motor shaft 120 with respect to a rotation about the motor shaft 120, an outer surface of the motor shaft 120 shown is provided with a flattening 121 on one side. An edge of the flattening 121 also defines a shoulder 122 for positive connection of the motor shaft 120 to the spacer sleeve 160 with respect to translation along the motor shaft 120.

[0086] A ring (not shown) may be secured to the motor shaft 120 at a further shoulder 122a, such that the spacer sleeve 160 is positively retained along the motor shaft 120 between the shoulder 122 and the ring with respect to translation along the motor shaft 120.

TABLE-US-00001 List of reference signs 100 Electric motor 110 Housing 111 Adapter insert 120 Motor shaft 121 Flattening 122 Shoulder 123 Ring 130 Stator 140 Drive rotor 141 Coil 150 Brake rotor 153 Depression 160 Spacer sleeve 163 Projection 164 Guide section 165 Inner cylinder 166 Outer cylinder 167 Web 168 Recess 169 Flattening 170 Bearing MA Motor axis