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EP-4353975-B1 - FAN MOTOR

EP4353975B1EP 4353975 B1EP4353975 B1EP 4353975B1EP-4353975-B1

Inventors

  • HWANG, JISU
  • Kim, Byungjik
  • HWANG, EUNJI
  • KIM, SUNGGI
  • Rhim, Yoonchul

Dates

Publication Date
20260506
Application Date
20230906

Claims (14)

  1. A fan motor comprising: a rotating shaft (102) to which an impeller (103) is mounted; a motor unit (111) including a rotor (112) connected to the rotating shaft (102) and a stator (114) enclosing the rotor (112), and driving the rotating shaft (102); a plurality of bearings (118; 118a, 118b) each having an inner ring (120) coupled to the rotating shaft (102), an outer ring (119) spaced apart from the inner ring (120) with a gap radially outward, and a plurality of balls (121) disposed to be rollable in contact between the outer ring (119) and the inner ring (120), and supporting the rotating shaft (102); a spring (130) having one axial side surface in contact with one axial side surface of the outer ring (119) of any one of the plurality of bearings (118); a cylinder (133) having one axial side in contact with another axial side surface of the spring (130), and another side in contact with one axial side surface of the outer ring (119) of another one of the plurality of bearings (118); a housing (100) in which the impeller (103) and the rotating shaft (102) are accommodated; a vane hub (106) accommodated inside the housing (100); a plurality of vanes (107) formed to protrude from an outer circumferential surface of the vane hub (106) to an inner circumferential surface of the housing (100) and coupled to the housing (100); and a bearing housing (108) accommodated inside the vane hub (106) and accommodating the plurality of bearings (118), the spring (130), and the cylinder (133), wherein the bearing housing (108) comprises a stopper (110) protruding radially inward from one axial end portion of the bearing housing (108), wherein the stopper (110) comes into contact with the outer ring (119) of a bearing (118b) that is arranged in an opposite direction to the impeller (103) among the plurality of bearings (118; 118a, 118b).
  2. The fan motor of claim 1, wherein the spring (130) is formed in a cylindrical shape enclosing the rotating shaft (102), and an axial length of the spring (130) is shorter than a diameter of the spring (130).
  3. The fan motor of claim 1 or 2, wherein the cylinder (133) surrounds the rotating shaft (102), and a spring mounting part (1331) to which the spring (130) is mounted is disposed on the one axial side of the cylinder (133), wherein the spring mounting part (1331) protrudes radially inward from the one axial side of the cylinder (133), a fixing protrusion protrudes from an inner end portion of the spring mounting part (1331) toward the bearing (118a), and the another axial side surface of the spring (130) surrounds the fixing protrusion and is fitted to the fixing protrusion.
  4. The fan motor of any one of claims 1 to 3, wherein a diameter of the cylinder (133) is equal to or smaller than a diameter of the bearing (118).
  5. The fan motor of any one of claims 1 to.4, wherein the spring (130) and the cylinder (133) are mounted between the outer rings (119) of the plurality of bearings (118), a sum of lengths of the spring (130) and the cylinder (133) before being mounted is larger than a spaced distance between the inner rings (120) of the plurality of bearings (118), and the spring (130) and the cylinder (133) after being mounted are configured to press the outer rings (119) of the plurality of bearings (118) in the axial direction, and a portion of the outer ring (119) of each of the plurality of bearings (118) protrudes axially from one axial side surface of the inner ring (120) of each of the plurality of bearings (118) by pressing force of the spring (130) and the cylinder (133).
  6. The fan motor of any one of claims 1 to 5, wherein a virtual straight line, which passes in a radial direction of the ball (121) through a first contact point where the outer ring (119) and the ball (121) are in contact with each other and a second contact point where the inner ring (120) and the ball (121) are in contact with each other, is inclined with respect to the axial direction.
  7. The fan motor of any one of claims 1 to 6, wherein the spring (130) comprises: a ring portion (131) disposed to be axially spaced apart from the one axial side surface of the outer ring (119) and surrounding the rotating shaft (102); and an arm portion (132) protruding from the ring portion (131) toward the bearing (118) to be in contact with the one axial side surface of the outer ring (119), and elastically deformed in the axial direction by the contact.
  8. The fan motor of claim 7, wherein the arm portion (132) includes a first arm portion (132a) and a second arm portion (132b) connected to outside of the ring portion (131), extending from the outside of the ring portion (131) in opposite directions along a circumferential direction, and forming a pair, the first arm portion (132a) and the second arm portion (132b) are provided in a plurality of pairs, and the plurality of pairs of arm portions are spaced apart from each other in a circumferential direction of the ring portion (131), and wherein each of the first arm portion (132a) and the second arm portion (132b) comprises: a connecting part (1321) connected to the outside of the ring portion (131); an inclined part (1322) inclined to protrude toward the bearing (118) from the connecting part (1321); and a contact part (1323) disposed on the inclined part (1322) and coming in contact with the one axial side surface of the outer ring (119).
  9. The fan motor of any one of claims 1 to 8, wherein the spring (230) comprises: a first contact portion (231) in contact with the one axial side surface of the outer ring (119); a second contact portion (233) spaced apart from the first contact portion (231) in the axial direction and coming in contact with the one axial side surface of the cylinder (133); and an elastic part (232) disposed between the first contact portion (231) and the second contact portion(233) to connect the first contact portion (231) and the second contact portion (233), and elastically deformed according to a distance between the first contact portion (231) and the second contact portion (233), wherein the first contact portion (231) and the second contact portion (233) are formed in a circular shape, the elastic part (232) comprises: a first curved part (2321) extending in a circumferential direction of the first contact part (1323) or the second contact part (1323) and convex toward the first contact part (1323); and a second curved part (2322) extending in the circumferential direction of the first contact part (1323) or the second contact part (1323), concave toward the second contact part (1323), and alternately disposed with the first curved part (2321) along the circumferential direction, the elastic part (232) is provided in plurality, and the plurality of elastic parts overlap each other in the axial direction, and the first curved part (2321) and the second curved part (2322) disposed on different layers in the axial direction are in contact with each other or spaced apart from each other in the axial direction.
  10. The fan motor of any one of claims 1 to 6, wherein the spring (330) is configured as a coil spring, and one side of the coil spring is in contact with the one axial side surface of the outer ring (119), and another side of the coil spring is in contact with the one axial side surface of the cylinder (133).
  11. The fan motor of any one of claims 1 to 10, wherein the plurality of bearings (118) are disposed between the impeller (103) and the rotor (112).
  12. The fan motor of any one of claims 1 to 11, wherein a plurality of bridges (109) extend between an inner circumferential surface of the vane hub (106) and an outer circumferential surface of the bearing housing (108) to connect the vane hub (106) and the bearing housing (108), wherein the stopper (110) restricts an axial movement of the outer ring (119), and the outer ring (119) is disposed to be in contact with the stopper (110), and the inner ring (120) is spaced apart from the stopper (110) in the axial direction.
  13. The fan motor of any one of claims 1 to 12, wherein the impeller (103) comprises: a hub (105) accommodated inside the housing (100) and having an accommodation space defined therein; and a plurality of blades (104) protruding from an outer circumferential surface of the hub (105) toward an inner circumferential surface of the housing (100), and a portion of the bearing housing (108) is accommodated in the accommodation space of the hub (105).
  14. The fan motor of claim 1, wherein the plurality of bearings (118) comprises: a first bearing (118a) disposed adjacent to the impeller (103); and a second bearing (118b) disposed adjacent to the motor unit (111), wherein the spring (130) in contact with one axial side surface of the first bearing (118a), to elastically press the one axial side surface of the first bearing (118a) in an axial direction, and the cylinder (133) disposed between the spring (130) and the second bearing (118b), to transfer elastic pressing force of the spring (130) to the second bearing (118b) through contact.

Description

TECHNICAL FIELD The present disclosure relates to a fan motor, and more particularly, to a fan motor capable of easily securing reliability of a bearing. BACKGROUND Electric motors may be installed in home appliances such as cleaners, hair dryers, and the like. A cleaner or a hair dryer may generate rotational force by using an electric motor as a power source. For example, an electric motor may be fastened to a fan. The fan may generate airflow by being rotated as driving force is applied from the electric motor. A handy stick cleaner or a hair dryer is operated while a user directly holds it by hand. In order to enhance user portability and convenience, there is a need to reduce size and weight of a cleaner or a hair dryer. In order to reduce a weight of a fan motor of a cleaner, it is preferable to use a plastic material, instead of a metal material, as a material for producing a housing. On the other hand, a plurality of bearings rotatably support a rotating shaft. Such bearings may have a double-side bearing support structure and a center bearing support structure depending on positions of the bearings disposed on a rotating shaft. FIG. 1 is a conceptual view illustrating a both-side bearing supporting structure. FIG. 2 is a conceptual view illustrating a center bearing supporting structure. According to a both-side bearing supporting structure of FIG. 1, a plurality of bearings 2a and 2b are mounted on both sides of a rotating shaft with a permanent magnet interposed therebetween. The rotating shaft may rotate while being supported by the plurality of bearings 2a and 2b. The both-side bearing supporting structure is configured such that the bearings 2a and 2b are disposed on both sides of the rotating shaft with the relatively heavy permanent magnet interposed therebetween, which provides an advantage of stably supporting the rotating shaft. However, the both-side bearing supporting structure separately requires a first housing supporting the first bearing 2a as one of the plurality of bearings 2a and 2b, and a second housing supporting the second bearing 2b as another one of the plurality of bearings 2a and 2b, which causes a disadvantage in view of reducing size and weight of a fan motor. Also, when the two different housings are assembled, an axial alignment between the first bearing 2a and the second bearing 2b may be failed. According to a center bearing supporting structure of FIG. 2, a plurality of bearings 11 and 12 are mounted on the middle of a rotating shaft 10 between an impeller 14 and a permanent magnet 13. The rotating shaft 10 may be supported and rotated by the plurality of bearings 11 and 12. In the case of the center bearing supporting structure, the plurality of bearings 11 and 12 may be disposed adjacent to each other and supported by one housing. This excludes the need of two separate housings, which is advantageous in reducing size and weight of a fan motor. In addition, in the case of the center bearing supporting structure, since the plurality of bearings 11 and 12 are accommodated and supported in the one housing, an axial mis-alignment between the bearings 11 and 12 is not caused. A bearing supporting a rotating shaft 20 may be configured as a ball bearing 24. FIG. 3 is a conceptual view for explaining the problem of the ball bearing 24 mounted on the rotating shaft 20. The ball bearing 24 includes an inner ring 21, an outer ring 22, and a plurality of balls 23. The inner ring 21 is configured to surround the rotating shaft 20. The outer ring 22 is disposed outside the inner ring 21 and surrounds the inner ring 21. The plurality of balls 23 are disposed between the inner ring 21 and the outer ring 22. The plurality of balls 23 may support the inner ring 21 so that the rotating shaft 20 and the inner ring 21 are rotatable relative to the outer ring 22. Ball accommodating grooves 25a and 25b are formed concavely on an inner circumferential surface of the outer ring 22 and an outer circumferential surface of the inner ring 21, respectively. The ball accommodating grooves 25a and 25b surround portions of the ball 23. An oil accommodating space S is defined between the ball 23 and the ball accommodating grooves 25a and 25b of the outer ring 22 and the inner ring 21. Oil accommodated in the oil accommodating space S may reduce friction between the outer ring 22 and the inner ring 21 and the ball 23. However, the ball 23 may move minutely to one side in the oil accommodating space between the outer ring 22 and the inner ring 21. Due to the movement, the ball 23 rubs against the outer ring 22 and the inner ring 21 during high-speed rotation, so as to be worn. In addition, there is a problem in that reliability of the bearing is lowered due to vibration and noise of the bearing. In order to solve this problem, force (preload) may be applied to the outer ring 22 in the axial direction, to minimize such minute movement of the ball 23 between the outer ring 22 and the inner ring 21. For