Brushless DC motor and drain pump having the same

1. A motor, comprising:

a first housing having an opening;

a rotor including a rotation shaft extending in an axial direction, inserted into the opening and rotatably provided outside the first housing;

a second housing coupled to the first housing to form a predetermined space together with an outer circumferential surface of the opening;

a stator fixedly provided in the space;

and

a seal coupled to the first housing and positioned to surround the rotation shaft,

wherein:

the rotation shaft protrudes from the rotor and extends in an axial direction,

the seal includes:

a sealing base rotatably coupled to the rotation shaft,

a gasket positioned to contact a plurality of points on an outer circumferential surface of the rotation shaft, and

a sealing cover coupled to the sealing base to fix the gasket to the sealing base, and

the sealing base includes a first annular protrusion and a second annular protrusion that are radially spaced from the rotation shaft and are positioned to support the gasket,

the sealing cover includes:

a first vertical wall spaced apart from the rotation shaft to have a cylindrical shape,

a second vertical wall spaced apart from the first vertical wall to have a cylindrical shape,

a first horizontal plate coupled to an inner side of the first vertical wall,

a second horizontal plate coupled to an outer side of the first vertical wall and to an inner side of the second vertical wall, and

a rib protruded from an outer surface of the first horizontal plate and toward the gasket, and

a portion of the gasket in contact with the rib corresponds to a portion of the gasket in contact with the first annular protrusion.

2. The motor of claim 1 , wherein the first annular protrusion is formed radially closer to the rotation axis than the second annular protrusion.

3. The motor of claim 2 , wherein the first annular protrusion and the second annular protrusion extend from a surface of the sealing base facing the gasket.

4. The motor of claim 3 , wherein the second annular protrusion is further protruded from the surface of the sealing base than the first annular protrusion.

5. The motor of claim 2 , wherein the gasket has a thickness adjacent to the first annular protrusion that is relatively greater than a thickness adjacent to the second annular protrusion.

6. The motor of claim 5 , wherein an area of a surface of the second annular protrusion in contact with the gasket is relatively larger than an area of a surface of the first annular protrusion in contact with the gasket.

7. The motor of claim 2 , wherein:

a first opening is formed at a center of the sealing base,

the rotation shaft passes through the first opening, and

the first annular protrusion is formed closer to the first opening than the second annular protrusion.

8. The motor of claim 7 , wherein the sealing base has a thickness that is relatively greater between a circumference of the first opening and an inner circumferential surface of the first annular protrusion than between an outer circumferential surface of the first annular protrusion and an inner circumferential surface of the second annular protrusion.

9. The motor of claim 1 , wherein:

a second opening is formed at a center of the first horizontal plate,

the rotation shaft passes through the second opening, and

the sealing cover further includes another rib extending radially inward toward the rotation shaft from an inner end of the first horizontal plate and spaced apart from the rotation shaft.

10. The pump motor of claim 9 , wherein the rib protruded from the outer surface of the first horizontal plate is provided between the other rib and the first vertical wall, and is formed to contact the gasket.

11. The motor of claim 10 , wherein an area of a surface, of the rib protruded from the outer surface of the first horizontal plate, in contact with the gasket is smaller than an area of a surface of the first annular protrusion in contact with the gasket.

12. The motor of claim 1 , wherein the first horizontal plate is coupled to the first vertical wall and spaced apart from the second horizontal plate on an axial direction of the rotation shaft.

13. The motor of claim 12 , wherein the second vertical wall is protruded from an outer surface of the second horizontal plate and toward the gasket.

14. The motor of claim 13 , wherein the second vertical wall is inserted into an inner surface of the first housing.

15. The motor of claim 1 , wherein the gasket includes:

a gasket body in contact with the sealing cover and the sealing base,

an interior extension protruding from an inner surface of the gasket body with respect to the rotation shaft to be brought into contact with the rotation shaft, and

an exterior extension provided on an outer surface of the gasket body with respect to the rotation shaft to support the gasket body.

16. The pump motor of claim 15 ,

wherein:

a third opening is formed at the center of the interior extension to allow the rotation shaft to pass therethrough,

an inner circumferential surface of the third opening is formed in contact with an outer circumferential surface of the rotation shaft, and

the exterior extension includes a plurality of branches extending from the gasket body, and

wherein at least one of the branches extends toward the rotation shaft.

17. The pump motor of claim 16 , wherein the branches form one or more spaces to store a lubricant adjacent to the rotation shaft.

18. The motor of claim 1 , wherein a distance between the second horizontal plate and the sealing base is greater than a distance between the first horizontal plate and the sealing base.

19. The motor of claim 1 , wherein a width of the rib is less than a width of the first annular protrusion.

20. The motor of claim 1 , further comprising an impeller coupled to the rotation shaft.

21. A motor, comprising:

a first housing having an opening;

a rotor including a rotation shaft extending in an axial direction, inserted into the opening and rotatably provided outside the first housing;

a second housing coupled to the first housing to form a space together with an outer circumferential surface of the opening;

a stator fixedly provided in the space;

and

a seal coupled to the first housing and positioned to surround the rotation shaft,

wherein:

the rotation shaft protrudes from the rotor and extends in an axial direction,

the seal includes:

a sealing base rotatably coupled to the rotation shaft,

a gasket positioned to contact a plurality of points on an outer circumferential surface of the rotation shaft, and

a sealing cover coupled to the sealing base to fix the gasket to the sealing base,

the sealing base includes an annular protrusion positioned to support the gasket,

the gasket includes:

a gasket body in contact with the sealing cover and the sealing base, and

at least one branch, of a plurality of branches extending from the gasket body, to contact the rotation shaft,

the sealing cover includes:

a first vertical wall spaced apart from the rotation shaft to have a cylindrical shape,

a second vertical wall spaced apart from the first vertical wall to have a cylindrical shape,

a first horizontal plate coupled to an inner side of the first vertical wall,

a second horizontal plate coupled to an outer side of the first vertical wall and to an inner side of the second vertical wall, and

a rib protruded from an outer surface of the first horizontal plate and toward the gasket, and

a portion of the gasket in contact with the rib corresponds to a portion of the gasket in contact with the annular protrusion.