Electronically commutated motor with bearing chamber defined by opposing abutment surfaces
An easy-to-assemble electric motor ( 21 ) features an internal stator ( 50 ), an external rotor ( 22 ) having a shaft ( 34 ), which external rotor is configured as a rotor cup or bell ( 24 ) having an outer side and an inner side ( 25 ), a bearing tube ( 70 ) for receiving a bearing arrangement ( 60 ) journaling the shaft ( 34 ), which bearing tube ( 70 ) has a first end portion ( 71 ) facing toward the inner side ( 25 ) of the external rotor ( 22 ) and being formed with an inwardly protruding stop ( 73 ), the bearing tube having a second end portion ( 75 ) facing away from the first end portion ( 71 ) and being joined to a plastic part ( 80 ) that likewise forms an inwardly protruding stop ( 77 ) adjacent a second end portion ( 75 ), the bearing arrangement ( 60 ) being located in the bearing tube ( 70 ) in a chamber defined between said two inwardly protruding stops ( 73, 77 ).
1. An electric motor ( 21 ) that comprises:
an internal stator ( 50 );
an external rotor ( 22 ) having a shaft ( 34 ), which external rotor is configured as a rotor cup ( 24 ) having an outer side and an inner side ( 25 );
a bearing tube ( 70 ) for reception of a bearing arrangement ( 60 ) journaling the shaft ( 34 ), which bearing tube ( 70 ) has a first end portion ( 71 ) facing toward said inner side ( 25 ) of the external rotor ( 22 ) and being formed with an inwardly protruding stop ( 73 ),
said tube having a second end portion ( 75 ) facing away from the first end portion ( 71 ) and being joined to a plastic part ( 80 ) that likewise forms an inwardly protruding stop ( 77 ) adjacent said second end portion ( 75 ), the bearing arrangement ( 60 ) being arranged in a chamber defined by the bearing tube ( 70 ) between said two inwardly protruding stops ( 73 , 77 ).
2. The motor according to claim 1 , wherein
an inner side of the second end portion ( 75 ) of the bearing tube ( 70 ) has an enlargement ( 78 ) to facilitate introduction of the bearing arrangement ( 60 ) into the bearing tube ( 70 ).
3. The motor according to claim 2 , wherein
a plastic element ( 65 ′) is arranged in a region between the bearing arrangement ( 60 ) and the enlargement ( 78 ) of the second end portion ( 75 ) of the bearing tube ( 70 ).
4. The motor according to claim 2 , wherein the outer side of the bearing tube ( 70 ) comprises a shoulder ( 79 ) adjacent said enlargement ( 78 ) of the second end portion ( 75 ).
5. The motor according to claim 1 , wherein
the bearing arrangement ( 60 ) comprises a first rolling bearing ( 72 ) and a second rolling bearing ( 76 ) which each comprise an outer ring ( 72 ″, 76 ″) and an inner ring ( 72 ′, 76 ′),
the first rolling bearing ( 72 ) being arranged adjacent the first end portion ( 71 ), and the second rolling bearing ( 76 ) adjacent the second end portion ( 75 ), of the bearing tube ( 70 ).
6. The motor according to claim 5 , wherein
an end face ( 72 ′″) of the outer ring ( 72 ″) of the first rolling bearing ( 72 ) abuts against said stop ( 73 ) at the first end portion ( 71 ) of the bearing tube ( 70 ).
7. The motor according to claim 5 , wherein
an end face ( 76 ′″) of the outer ring ( 76 ″) of the second rolling bearing ( 76 ) abuts against said stop ( 77 ) at the second end portion ( 75 ) of the bearing tube ( 70 ).
8. The motor according to claim 5 , further comprising
between the outer ring ( 72 ″) of the first rolling bearing ( 72 ) and the outer ring ( 76 ″) of the second rolling bearing ( 76 ) a spacing member ( 74 ) which assures a predetermined distance between the outer bearing rings ( 72 ″, 76 ″).
9. The motor according to claim 8 , wherein
an end face ( 72 IV ) of the one outer ring ( 72 ″) abuts against a first face of the spacing member ( 74 ), and an end face ( 76 IV ) of the other outer ring ( 76 ″) abuts against a second face of the spacing member ( 74 ).
10. The motor according to claim 5 , wherein
the inner ring ( 76 ′) of the second rolling bearing ( 76 ) abuts an annular supporting member ( 92 ) which is secured on the shaft ( 34 ) of the external rotor ( 22 ).
11. The motor according to claim 10 , wherein the annular supporting member is implemented as a snap ring ( 92 ).
12. The motor according to claim 5 , wherein
there is provided, between an inner surface ( 25 ) of the external rotor ( 22 ) and the inner ring ( 72 ′) of the first rolling bearing ( 72 ″), a compression spring ( 94 ) that biases said inner ring ( 72 ′) in the direction of the second rolling bearing ( 76 ).
13. The motor according to claim 1 , wherein the bearing tube ( 70 ) is a shaped element made of metal.
14. The motor according to claim 1 , further comprising a fan wheel ( 20 , 23 ) coupled for rotation with said rotor ( 22 ).
15. The motor according to claim 14 , wherein the plastic part ( 80 ) is implemented as a flange of the fan ( 20 ).
16. The motor according to claim 15 , wherein the plastic part ( 80 ) is joined to a cover part ( 40 ) to form a fan housing.
17. The motor according to claim 16 , wherein the cover part ( 40 ) is coupled to the plastic part ( 80 ) by interengaging latching elements ( 42 ′, 47 ′).
18. The motor according to claim 1 , wherein a fan wheel ( 23 ) is provided on the rotor cup ( 24 ).
19. The motor according to claim 18 , further comprising a hub ( 30 ) which connects the rotor cup ( 24 ) to one end portion ( 32 ) of the shaft ( 34 ).
20. The motor according to claim 18 , further comprising fan blades ( 26 ) provided on the fan wheel ( 23 ).
21. The motor according to claim 14 , wherein the motor is an electronically commutated motor.
22. The motor according to claim 1 , wherein said plastic part ( 80 ) , which serves as an inwardly projecting stop ( 77 ) adjacent the second end section ( 75 ), is formed as an injection-molded part, which is pressed into the bearing tube ( 70 ).